WorldWideScience

Sample records for faa lightning protection

  1. Faraday Cage Protects Against Lightning

    Science.gov (United States)

    Jafferis, W.; Hasbrouck, R. T.; Johnson, J. P.

    1992-01-01

    Faraday cage protects electronic and electronically actuated equipment from lightning. Follows standard lightning-protection principles. Whether lightning strikes cage or cables running to equipment, current canceled or minimized in equipment and discharged into ground. Applicable to protection of scientific instruments, computers, radio transmitters and receivers, and power-switching equipment.

  2. Lightning protection of PV systems

    OpenAIRE

    Pons, Enrico; Tommasini, Riccardo

    2013-01-01

    Lightning strikes can affect photovoltaic (PV) generators and their installations, involving also the inverter's electronics. It is therefore necessary to evaluate the risk connected to lightning strikes in order to adopt the correct protective measures for the system. The Standard IEC (EN) 62305-2 reports the procedures for the risk calculation and for the choice of proper lightning protection systems. Usually the technical guidelines suggest protecting with SPDs (surge protective devices) b...

  3. Wind turbine with lightning protection system

    DEFF Research Database (Denmark)

    2016-01-01

    The present invention relates to a wind turbine comprising a lightning protection system comprising a waveguide interconnecting a communication device and a signal-carrying structure. In other aspects, the present invention relates to the use of a waveguide in a lightning protection system...... of a wind turbine, a power splitter and its use in a lightning protection system of a wind turbine....

  4. Space Launching Site Protection against Lightning Hazards

    OpenAIRE

    Issac, F.; Bachelier, E.; Prost, D.; Enjalbert, V.; Mohedano, L.

    2012-01-01

    International audience; A launching pad, because of its activity, is particularly sensitive to the risk of lightning. The use of Standard IEC62305 "Protection against lightning" establishes the general framework for the Lightning Protection System (LPS). However, the specific activity of a launching pad requires special analysis on specific points of the LPS. Indeed, it is necessary to take into account the lightning conductor system particularity on the one hand, and the launcher electromagn...

  5. Lightning protection of wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, T.; Brask, M.H. [DEFU (Denmark); Jensen, F.V.; Raben, N. [SEAS (Denmark); Saxov, J. [Nordjyllandsvaerket (Denmark); Nielsen, L. [Vestkraft (Denmark); Soerensen, P.E. [Risoe National Lab. (Denmark)

    1999-03-01

    Lightning damage to wind turbines is a serious problem for Danish power companies, who have experienced some cases with very costly lightning damage and a large number of cases with minor damage. The most costly cases include one catastrophic damage to an entire wind turbine, and several cases of destruction of blades, main bearings, generators and control systems. Over the years there have been several hundreds of cases with minor damage - typically damage and interruptions of the control and communication systems, or the power systems. The Danish power companies anticipate that the lightning threat will be even bigger for the large off-shore wind turbine installations that are currently being planned in Denmark. Furthermore, it is known from the off-shore wind turbines at Vindeby in Denmark that the costs of inspection and particularly repair work must be expected to be much higher off-shore as compared to wind turbines on land. These considerations was the background for a two year project concerned with investigation of lighting damages and with the formulation of a DEFU Recommendation for lightning protection of wind turbines, which was published in January 1999. The project was funded by the Danish power companies Elsam, Eltra, Elkraft and by DEFU. (au)

  6. Protection of LV system against lightning

    OpenAIRE

    Yordanova Nedyalkova, Greta

    2010-01-01

    Lightning is a natural hazard and one of the greatest local mysteries. Scientists have not fully understood the mechanism of lightning. It is one of the most beautiful displays in nature and one of the nature's most dangerous phenomenon known to man. Overvoltage due to lightning is a very important problem of LV systems. Some lightning flashes damage buildings and a few kill or injure people and animals, either directly or indirectly, by causing fire and explosions. The need for protect...

  7. The 1st Asian Lightning Protection Forum

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ The First Asian Lightning Protection Forum was held on October 28-29, 2003 in Beijing, China.The forum was sponsored by the China Association for Standardization and was organized by Chinese National Committee for Lightning Protection Technology Standardization, Department of Electrical Engineering Tsinghua University, China Electricity Council, Zhongguang High-tech Industrial Development Co.,Ltd, and Lightning Protection Center of Guangdong Province.

  8. Lightning Protection and Detection System

    Science.gov (United States)

    Dudley, Kenneth L. (Inventor); Szatkowski, George N. (Inventor); Woodard, Marie (Inventor); Nguyen, Truong X. (Inventor); Ely, Jay J. (Inventor); Wang, Chuantong (Inventor); Mielnik, John J. (Inventor); Koppen, Sandra V. (Inventor); Smith, Laura J. (Inventor)

    2017-01-01

    A lightning protection and detection system includes a non-conductive substrate material of an apparatus; a sensor formed of a conductive material and deposited on the non-conductive substrate material of the apparatus. The sensor includes a conductive trace formed in a continuous spiral winding starting at a first end at a center region of the sensor and ending at a second end at an outer corner region of the sensor, the first and second ends being open and unconnected. An electrical measurement system is in communication with the sensor and receives a resonant response from the sensor, to perform detection, in real-time, of lightning strike occurrences and damage therefrom to the sensor and the non-conductive substrate material.

  9. 76 FR 33129 - Airworthiness Standards; Electrical and Electronic System Lightning Protection

    Science.gov (United States)

    2011-06-08

    ...). Under that section, the FAA is charged with prescribing regulations to promote safe flight of civil... History Existing regulations for the lightning protection of electrical and electronic systems installed...-by- case evaluation based on engineering and flight crew assessment of the specific function and...

  10. 75 FR 16676 - Airworthiness Standards; Electrical and Electronic System Lightning Protection

    Science.gov (United States)

    2010-04-02

    ... concepts, terminology, and practices. Parts 23, 27 and 29 regulations for lightning protection are less... Transportation Order DOT 2100.5 prescribes policies and procedures for simplification, analysis, and review of... recommendations of the ARAC are available at the following Web address: http://www.faa.gov/regulations_policies...

  11. Integral lightning protection system in petroleum facilities

    Energy Technology Data Exchange (ETDEWEB)

    Torres, Horacio; Gallego, Luis; Montana, Johny; Younes, Camilo; Rondon, Daniel; Gonzalez, Diego; Herrera, Javier; Perez, Ernesto; Vargas, Mauricio; Quintana, Carlos; Salgado, Milton [Universidad Nacional de Colombia, Bogota (Colombia)]. E-mail: paas@paas.unal.edu.co

    2001-07-01

    This paper presents an Integral Lightning Protection System, focused mainly in petroleum facilities and applied to a real case in Colombia, South America. As introduction it is presented a summary of the incidents happened in last years, a diagnosis and the proposal of solution. Finally, as part of the analysis, a lightning risk assessment for the Central Process Facility is showed. (author)

  12. Lightning protection system for a wind turbine

    Science.gov (United States)

    Costin, Daniel P [Chelsea, VT; Petter, Jeffrey K [Williston, VT

    2008-05-27

    In a wind turbine (104, 500, 704) having a plurality of blades (132, 404, 516, 744) and a blade rotor hub (120, 712), a lightning protection system (100, 504, 700) for conducting lightning strikes to any one of the blades and the region surrounding the blade hub along a path around the blade hub and critical components of the wind turbine, such as the generator (112, 716), gearbox (708) and main turbine bearings (176, 724).

  13. Numerical tools for lightning protection of wind turbines

    DEFF Research Database (Denmark)

    Madsen, Søren Find; Mieritz, Casper Falkenstrøm; Candela Garolera, Anna

    2013-01-01

    The present paper presents the different numerical tools used for lightning protection analysis. Initially the risk assessment considering attachment point distribution and location of vulnerable points on the wind turbine will be discussed, where also the term Lightning Protection Coordination (...

  14. Frequency domain analysis of lightning protection using four lightning protection rods

    Directory of Open Access Journals (Sweden)

    Javor Vesna

    2008-01-01

    Full Text Available In this paper the lightning discharge channel is modeled as a vertical monopole antenna excited by a pulse generator at its base. The lightning electromagnetic field of a nearby lightning discharge in the case of lightning protection using four vertical lightning protection rods was determined in the frequency domain. Unknown current distributions were determined by numerical solving of a system of integral equations of two potentials using the Point Matching Method and polynomial approximation of the current distributions. The influence of the real ground, treated as homogeneous loss half-space of known electrical parameters, expressed through a Sommerfeld integral kernel, was modeled using a new Two-image approximation which gives good results in both near and far fields.

  15. Application and Analysis for Surge Arrester on Lightning Protection of Distribution Network

    Directory of Open Access Journals (Sweden)

    Wang Daxing

    2016-01-01

    Full Text Available In order to effectively reduce lightning stroke outage rate, effect of lightning protection with surge arrester on transmission line has been generally acknowledged relative to other lightning protection measures. This article introduces in such aspects as the working principle of line surge arrester and effect of lightning protection, and also explores application for lightning arrester of distribution network to achieve difference lightning protection and improve the lightning protection performance of distribution network.

  16. Application and Analysis for Surge Arrester on Lightning Protection of Distribution Network

    Directory of Open Access Journals (Sweden)

    Wang Daxing

    2015-01-01

    Full Text Available In order to effectively reduce lightning stroke outage rate, effect of lightning protection with surge arrester on transmission line has been generally acknowledged relative to other lightning protection measures. This article introduces in such aspects as the working principle of line surge arrester and effect of lightning protection, and also explores application for lightning arrester of distribution network to achieve difference lightning protection and improve the lightning protection performance of distribution network.

  17. 14 CFR 29.610 - Lightning and static electricity protection.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Lightning and static electricity protection... § 29.610 Lightning and static electricity protection. (a) The rotorcraft structure must be protected... electricity must— (1) Minimize the accumulation of electrostatic charge; (2) Minimize the risk of electric...

  18. 14 CFR 27.610 - Lightning and static electricity protection.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Lightning and static electricity protection....610 Lightning and static electricity protection. (a) The rotorcraft must be protected against... static electricity must— (1) Minimize the accumulation of electrostatic charge; (2) Minimize the risk of...

  19. 14 CFR 23.954 - Fuel system lightning protection.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel system lightning protection. 23.954 Section 23.954 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Fuel System § 23.954 Fuel system lightning protection. The fuel system must be designed and arranged...

  20. Properties of Lightning Strike Protection Coatings

    Science.gov (United States)

    Gagne, Martin

    Composite materials are being increasingly used by many industries. In the case of aerospace companies, those materials are installed on their aircraft to save weight, and thus, fuel costs. These aircraft are lighter, but the loss of electrical conductivity makes aircraft vulnerable to lightning strikes, which hit commercial aircrafts on average once per year. This makes lightning strike protection very important, and while current metallic expanded copper foils offer good protection, they increase the weight of composites. Therefore, under the CRIAQ COMP-502 project, a team of industrial partners and academic researchers are investigating new conductive coatings with the following characteristics: High electromagnetic protection, high mechanical resistance, good environmental protection, manufacturability and moderate cost. The main objectives of this thesis, as part of this project, was to determine the main characteristics, such as electrical and tribomechanical properties, of conductive coatings on composite panels. Their properties were also to be tested after destructive tests such as current injection and environmental testing. Bombardier Aerospace provided the substrate, a composite of carbon fiber reinforced epoxy matrix, and the current commercial product, a surfacing film that includes an expanded copper foil used to compare with the other coatings. The conductive coatings fabricated by the students are: silver nanoparticles inside a binding matrix (PEDOT:PSS or a mix of Epoxy and PEDOT:PSS), silvered carbon nanofibers embedded in the surfacing film, cold sprayed tin, graphene oxide functionalized with silver nanowires, and electroless plated silver. Additionally as part of the project and thesis, magnetron sputtered aluminum coated samples were fabricated. There are three main types of tests to characterize the conductive coatings: electrical, mechanical and environmental. Electrical tests consist of finding the sheet resistance and specific resistivity

  1. Protection of large wind turbine blades against lightning

    OpenAIRE

    Montañá Puig, Juan; Rachidi-Haeri, Farhad; Rubinstein, Marcos; Bermúdez, José Luis; Solà de Las Fuentes, Gloria; Hermoso Alameda, Blas

    2008-01-01

    Lightning protection of modern wind turbines presents a number of new challenges due to the geometrical, electrical and mechanical particularities of the turbines. The risk assessment requires the estimation of the number of expected strikes. In the case of modern turbines, most of the expected lightning flashes will be upward. In addition, due to the rotation of the blades, modern wind turbines may trigger their own lightning. Moreover, since wind turbines are becoming tall struc...

  2. General Survey for Lightning Protection Standards Development in China

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ The introduction of IEC/TC81 Thunderstorms are natural weather phenomena and there are no devices or methods capable of preventing lightning discharges. Lightning flashes striking structures or services entering the structures, or striking earth nearby are hazardous to people, to the structures themselves, their contents and installations, as well as to services.Hence lightning protection is very important for national economic development. The international trade in lightning protection measures integrat ed in plants or buildings is of increasing importance:more than 500 million USD, world wide are estimated today; consequent loss, where protection measures are not provided, is some order of magnitude higher.The number of countries where lightning protection is required either by law or by insurance companies is growing. Some countries have conflicting national rules and many developing countries do not have the relevant international standards, making the need for such standards all the more urgent.

  3. Designing concept on lightning protection of overhead power distribution line

    Energy Technology Data Exchange (ETDEWEB)

    Yokoyama, Shigeru [Central Research Institute of Electric Power Industry, Kanagawa-ken (Japan)], E-mail: yokoyama@criepi.denken.or.jp

    2007-07-01

    The principle is shown for lightning protection of power distribution lines taking the effects of surge arresters, overhead ground wires and their combined use into consideration. Moreover an outline of a rational design method targeting direct lightning hits, induced over voltages and back flow currents from high structures. (author)

  4. 21st Century Lightning Protection for High Altitude Observatories

    Science.gov (United States)

    Kithil, Richard

    2013-05-01

    One of the first recorded lightning insults to an observatory was in January 1890 at the Ben Nevis Observatory in Scotland. In more recent times lightning has caused equipment losses and data destruction at the US Air Force Maui Space Surveillance Complex, the Cerro Tololo observatory and the nearby La Serena scientific and technical office, the VLLA, and the Apache Point Observatory. In August 1997 NOAA's Climate Monitoring and Diagnostic Laboratory at Mauna Loa Observatory was out of commission for a month due to lightning outages to data acquisition computers and connected cabling. The University of Arizona has reported "lightning strikes have taken a heavy toll at all Steward Observatory sites." At Kitt Peak, extensive power down protocols are in place where lightning protection for personnel, electrical systems, associated electronics and data are critical. Designstage lightning protection defenses are to be incorporated at NSO's ATST Hawaii facility. For high altitude observatories lightning protection no longer is as simple as Franklin's 1752 invention of a rod in the air, one in the ground and a connecting conductor. This paper discusses selection of engineered lightning protection subsystems in a carefully planned methodology which is specific to each site.

  5. Common Practice Lightning Strike Protection Characterization Technique to Quantify Damage Mechanisms on Composite Substrates

    Science.gov (United States)

    Szatkowski, George N.; Dudley, Kenneth L.; Koppen, Sandra V.; Ely, Jay J.; Nguyen, Truong X.; Ticatch, Larry A.; Mielnik, John J.; Mcneill, Patrick A.

    2013-01-01

    To support FAA certification airworthiness standards, composite substrates are subjected to lightning direct-effect electrical waveforms to determine performance characteristics of the lightning strike protection (LSP) conductive layers used to protect composite substrates. Test results collected from independent LSP studies are often incomparable due to variability in test procedures & applied practices at different organizations, which impairs performance correlations between different LSP data sets. Under a NASA supported contract, The Boeing Company developed technical procedures and documentation as guidance in order to facilitate a test method for conducting universal common practice lightning strike protection test procedures. The procedures obtain conformity in future lightning strike protection evaluations to allow meaningful performance correlations across data sets. This universal common practice guidance provides the manufacturing specifications to fabricate carbon fiber reinforced plastic (CFRP) test panels, including finish, grounding configuration, and acceptable methods for pretest nondestructive inspection (NDI) and posttest destructive inspection. The test operations guidance elaborates on the provisions contained in SAE ARP5416 to address inconsistencies in the generation of damage protection performance data, so as to provide for maximum achievable correlation across capable lab facilities. In addition, the guidance details a direct effects test bed design to aid in quantification of the multi-physical phenomena surrounding a lightning direct attachment supporting validation data requirements for the development of predictive computational modeling. The lightning test bed is designed to accommodate a repeatable installation procedure to secure the test panel and eliminate test installation uncertainty. It also facilitates a means to capture the electrical waveform parameters in 2 dimensions, along with the mechanical displacement and thermal

  6. Lightning protection of oil and gas industrial plants

    Energy Technology Data Exchange (ETDEWEB)

    Bouquegneau, Christian [Polytechnical University of Mons (Belgium)

    2007-07-01

    The paper brings some cases and presents the general principles, what the IEC 62305 international standard says, the warning and avoidance and the conclusion about lightning protection of oil and gas industrial plants.

  7. Direct Write Lightning Protection and Damage Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project aims to improve conventional lightning strike protection in composite aircraft and proposes a novel method to monitor structures for damage upon...

  8. FAA Lightning Protection Study: Lightning-Induced Transients on Buried Shielded Transmission Lines

    Science.gov (United States)

    1975-06-01

    the use of the impedance transfer functions for a coaxial cable, as developed In Appendix B. As shown in the Appendix B, Ex PP’> Zee ext + Zel Int E x p...Laboratory. Kirtland AFB, New Mexico , May 1966. (9) Ref. 5, P. 33. 100) Sunde, E.D., Earth Conduction Effects In Transmission Systems, Dover Publications...Therefore, by superposition, E -PWP> Zee Iext+Z el Int (0.37) ExIP p< Zielx+Zii Iit (B.38) Notice that A rnA Therefore e - Ze Zei 60 For solid conductors (p

  9. Lightning protecting materials used on radar system

    NARCIS (Netherlands)

    Blaj, M.A.; Damstra, Geert C.; Buesink, Frederik Johannes Karel; Leferink, Frank Bernardus Johannes

    2009-01-01

    Because of the extensive use in modern systems of very sensitive electronic components, lightning strikes does not represent only a threat, but something that cannot be neglected anymore and safety hazards caused by direct and indirect lightning to the aircraft or naval industry. Everyday new materi

  10. Lightning Protection of Floating Roof Tanks

    Directory of Open Access Journals (Sweden)

    Adekitan,

    2013-10-01

    Full Text Available Prior to export, processed crude oil is stored in Floating Roof Tanks (FRT to further allow any trapped gas within the crude oil to escape, as this stabilises the crude oil. In the oil and gas industry, FRT’s are vital in the processing of crude oil to the acceptable export specification.In the tropics and other lightning prone regions, lightning induced floating roof tank fire constitutes a major threat to crude oil production. Among others, a single lightning incident could result in the loss of life, product and production time, avoidable incident review time, damaged equipment, wasted repair cost, bad publicity and loss of income.This paper therefore, is aimed at providing an effective solution to the menace of lightning induced tank fire by focussing on the starting process of the lightning induced fire and proposing alternative concepts for breaking the fire triangle before fire ensues

  11. Electromagnetic computation methods for lightning surge protection studies

    CERN Document Server

    Baba, Yoshihiro

    2016-01-01

    This book is the first to consolidate current research and to examine the theories of electromagnetic computation methods in relation to lightning surge protection. The authors introduce and compare existing electromagnetic computation methods such as the method of moments (MOM), the partial element equivalent circuit (PEEC), the finite element method (FEM), the transmission-line modeling (TLM) method, and the finite-difference time-domain (FDTD) method. The application of FDTD method to lightning protection studies is a topic that has matured through many practical applications in the past decade, and the authors explain the derivation of Maxwell's equations required by the FDTD, and modeling of various electrical components needed in computing lightning electromagnetic fields and surges with the FDTD method. The book describes the application of FDTD method to current and emerging problems of lightning surge protection of continuously more complex installations, particularly in critical infrastructures of e...

  12. Lightning protection for wind turbines in Vietnam

    Directory of Open Access Journals (Sweden)

    Thuan Nguyen

    2017-01-01

    Full Text Available Wind energy has become increasingly important in the total electrical energy supply mix in Vietnam over the last few years. Small, kW turbines were installed in isolated areas a decade ago, while wind farms of several MW to few hundred MW are now being connected directly to national grid, with many additional projects in planning or under construction to fulfill an objective of 6% of the total installed capacity by 2030 (approximately 6200 MW of wind energy component. The increase in wind farm generation results in increased damage from lightning. In this paper, the annual frequency of lightning strikes to wind turbines in Vietnam is calculated using electrogeometric model. Reported lightning incidents to three major wind farms in Vietnam are summarized. Possible causes of failure are discussed, and an EMTP simulation for each incident was performed accordingly. The simulations suggest the failure mechanisms as well the potential of improved grounding to reduce lightning induced damage in future windfarms.

  13. Lightning protection of flap system for wind turbine blades

    DEFF Research Database (Denmark)

    Candela Garolera, Anna; Madsen, Søren Find

    The aim of this PhD project was to investigate the behaviour of a Controllable Rubber Trailing Edge Flap (CRTEF) in a wind turbine blade when it is exposed to lightning discharges, and find the best technical solution to protect the CRTEF and the controlling system against lightning, based...... on the results of simulation models and high voltage tests. Wind turbines are a common target of lightning due to their height and location, and blades are the components most exposed to direct discharges. Protecting the blades against lightning is specially challenging, mainly because of the combination...... of a broader, EUDP funded project, whose overall objective was to develop a prototype active trailing edge flap system for a wind turbine blade which constitutes a complete, reliable and robust load control flap system for a full scale turbine, ready for prototype testing....

  14. A novel lightning protection technique of wind turbine components

    Directory of Open Access Journals (Sweden)

    M.A. Abd-Allah

    2015-12-01

    Full Text Available The lightning energy can be very harmful to wind turbine (WT farm components; therefore an effective lightning protection technique is required. In this study, a novel technique for WT components protection is presented. This technique used ferromagnetic rings placed around the WT blade roots. Ferrite ring was moulded into particular shapes from the powder of compounds of ferric oxide, manganese, and zinc, and then sintered. The dimensions of rings used are 990 mm (inner diameter, 1030 mm (outer diameter, and 100 mm (thickness. The effectiveness of the novel technique in overvoltage mitigation during lightning strokes is presented and discussed. The results show that the overvoltage is effectively damped with using this technique. The transient overvoltage at control devices is reduced to 16% of its original value, while at distribution system; it is reduced to 5% of its original value.

  15. Lightning Protection for the Orion Space Vehicle

    Science.gov (United States)

    Scully, Robert

    2015-01-01

    The Orion space vehicle is designed to requirements for both direct attachment and indirect effects of lightning. Both sets of requirements are based on a full threat 200kA strike, in accordance with constraints and guidelines contained in SAE ARP documents applicable to both commercial and military aircraft and space vehicles. This paper describes the requirements as levied against the vehicle, as well as the means whereby the design shows full compliance.

  16. National Renewable Energy Laboratory program on lightning risk and wind turbine generator protection

    Energy Technology Data Exchange (ETDEWEB)

    Muljadi, E [National Renewable Energy Lab., Golden, CO (United States); McNiff, B [McNiff Light Industry, Blue Hill, ME (United States)

    1997-09-01

    This paper will describe the NREL program for addressing lightning protection for wind turbines. A test program will begin this summer at the Central and South West Services Inc. (CSW) wind farm near Fort Davis, Texas, to assess lightning risk, the frequency of lightning strikes on wind turbines compared to risk assessment predictions, and the effectiveness of some protection techniques. A Web page will be assembled to provide resources for designers and operators and feedback for issues as they arise. Also, a database of lightning events (and corresponding damage) will be collected to assist in maturing the understanding of wind turbine lightning protection.

  17. Lightning

    Science.gov (United States)

    Pampe, William R.

    1970-01-01

    Presents basic physical theory for movement of electric charges in clouds, earth, and air during production of lightning and thunder. Amount of electrical energy produced and heating effects during typical thunderstorms is described. Generalized safety practices are given. (JM)

  18. Lightning Protection System for HE Facilities at LLNL - Certification Template

    Energy Technology Data Exchange (ETDEWEB)

    Clancy, T J; Ong, M M; Brown, C G

    2005-12-08

    This document is meant as a template to assist in the development of your own lighting certification process. Aside from this introduction and the mock representative name of the building (Building A), this document is nearly identical to a lightning certification report issued by the Engineering Directorate at Lawrence Livermore National Laboratory. At the date of this release, we have certified over 70 HE processing and storage cells at our Site 300 facilities. In Chapters 1 and 2 respectively, we address the need and methods of lightning certification for HE processing and storage facilities at LLNL. We present the preferred method of lightning protection in Chapter 3, as well as the likely building modifications that are needed to comply with this method. In Chapter 4, we present the threat assessment and resulting safe work areas within a cell. After certification, there may be changes to operations during a lightning alert, and this is discussed in Chapter 5. Chapter 6 lists the maintenance requirements for the continuation of lighting certification status. Appendices of this document are meant as an aid in developing your own certification process, and they include a bonding list, an inventory of measurement equipment, surge suppressors in use at LLNL, an Integrated Work and Safety form (IWS), and a template certification sign-off sheet. The lightning certification process involves more that what is spelled out in this document. The first steps involve considerable planning, the securing of funds, and management and explosives safety buy-in. Permits must be obtained, measurement equipment must be assembled and tested, and engineers and technicians must be trained in their use. Cursory building inspections are also recommended, and surge suppression for power systems must be addressed. Upon completion of a certification report and its sign-off by management, additional work is required. Training will be needed in order to educate workers and facility managers

  19. Draft IEC 61400-24 wind turbines: lightning protection blades

    OpenAIRE

    Hermoso Alameda, Blas; Montañá Puig, Juan

    2009-01-01

    Wind turbine blades are the most exposed parts of the turbine, and would experience the full impact from the electric fields as associated with the lightning attachment process, the lightning currents, and the magnetic field associated with lightning currents.At some point in time hopes were high that lightning would not strike blades made of non-conducting material only, but practical experiences have clearly demonstrated that this is not the case. Lightning does in fact st...

  20. The protection of photovoltaic power systems from lightning

    Science.gov (United States)

    Rogers, C. B.

    Lightning protection techniques at nine prototype photovoltaic power system sites with outputs from 18-225 kW are described. Noting that protection schemes are devised to fit isokeraunic data for specific sites, grounding is cited as a common feature for all systems. The grounds are, in separate instances, connected to junction boxes, frames of the solar cell panels, lead from the dc center, from the dc negative terminal, from the frames and equipment, at the array turntable, or from the building rebar frames. The dc power cables are protected by either metal conduit, metal conduit ground wire, direct burial, by rigid metal conduit, ground conductors, or by ground conductors at the ends of the conduit run. Costs run from 0.01-0.28$/W, with all the systems outfitted with bypass and blocking diodes. Direct stroke protection is viewed as less important than isokeraunic data.

  1. National Renewable Energy Laboratory program on lightning risk and wind turbine generator protection

    Energy Technology Data Exchange (ETDEWEB)

    Muljadi, E. [National Renewable Energy Lab., Golden, CO (United States); McNiff, B. [McNiff Light Industry, Blue Hill, ME (United States)

    1997-12-31

    In the early development of wind turbine generators (WTG) in the United States, wind farms were primarily located in California where lightning activity is the lowest in the United States. As such, lightning protection for wind turbines was not considered to be a major issue for designers or wind farm operators. However, wind turbine installations are expanding into the Midwest, Southwest and other regions of the United States where lightning activity is significantly more intense and lightning damage to wind turbines is more common. There is a growing need, therefore, to better understand lightning activity on wind farms and to improve wind turbine lightning protection systems. In support of the U.S. Department of Energy/Electric Power Research Institute (DOE/EPRI) Utility Wind Turbine Verification Program (TVP), the National Renewable Energy Laboratory (NREL) has recently begun to take steps to determine the extent of damage due to lightning and the effectiveness of various lightning protection techniques for wind power plants. Working through the TVP program, NREL will also perform outreach and education to (1) help manufacturers to provide equipment that is adequately designed to survive lightning, (2) make sure that operators are aware of effective safety procedures, and (3) help site designers and wind farm developers take the risk of lightning into account as effectively as possible.

  2. 14 CFR 23.867 - Electrical bonding and protection against lightning and static electricity.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Electrical bonding and protection against lightning and static electricity. 23.867 Section 23.867 Aeronautics and Space FEDERAL AVIATION... Electrical bonding and protection against lightning and static electricity. (a) The airplane must be...

  3. Building the International Testing and Certification Service for Lightning Protection Products

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Lightning Protective Devices Testing Center affiliated to Shanghai Lightning Protection Center (hereinafter referred to as “Testing Center”) is a third-party technical institution specialized in the testing of lightning protection equipment,which has passed the qualification certification and metrology accreditation of Certification and Accreditation Administratin of the People's Republic of China and is approved by China National Accreditation Service for Conformity Assessment Meanwhile,it is also a lightning products quality inspection institution authorized by Shanghai Municipal Bureau of Quality and Technical Superwsion and the only lightning products testing laboratory authorized by China Quality Certification Center.The Center has always attached great importance to the standardization work,and accumulated rich successful experiences in enhancing the testing capability and technical service level by means of standardization.

  4. Cyclic hygrothermal aging of aircraft lightning protections: Phenomenological overview

    KAUST Repository

    Lubineau, Gilles

    2012-04-23

    The recent transition to full composite fuselages is a major breakthrough in aeronautical design. To ensure satisfactory lightning protection, the electrical properties of the primary composite structure need to be improved and a design solution lies on bonding a metallic fishnet to the fuselage. An important issue is the prediction of the aging behavior of this top layer when exposed to severe aging conditions representative of flight environment. Multiple aging mechanisms affect this top layer made of thermoset resin and metallic fishnet with complex geometry and a first modeling strategy is a necessary starting point to better understand its evolution. This paper describes the overall phenomenology and the different mechanisms that can be expected in such a structure.

  5. Effects of Location, Size and Number of Wind Turbine Receptors on Blade Lightning Protection

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Electric and magnetic fields generated by lightning cause a serious hazard to various systems. Now wind turbine installations with higher power capacity are increasing. Higher power capacity requires higher height and so there is more probability of lightning strike. Blades are the most probable components )to be struck by lightning. The most common lightning protection system for the blades consists of several metallic receptors on the blade surface. Those are connected to the ground by metallic down-conductors placed inside the blade shell. This paper studies effects of the receptor configurations on protecting the blade against lightning strike, For this purpose, an analysis procedure based on finite element method (FEM) in COMSOL Multiphysics software environment is used. The voltage distribution around the blade is simulated for various configurations of receptors. The best configuration is presented. Simulations are performed on the blade model of a special wind turbine, which is "VESTAS V47".

  6. Lightning protection for the process canyons at the Savannah River site

    Energy Technology Data Exchange (ETDEWEB)

    McAfee, D.E.

    1995-12-31

    Westinghouse Savannah River Company (WSRC) has performed Lightning Studies for the existing Process Canyons at the Savannah River Site (SRS). These studies were initiated to verify the lightning protection systems for the facilities and to compare the installations to the National Fire Protection (NFPA) Standard 780, Lighting Protection Code, 1992. The original study of the F-Canyon was initiated to develop answers to concerns raised by the Defense Nuclear Facility Safety Board (DNFSB). Once this study was completed it was determined that a similar study for H-Canyon would be prudent; followed by an evaluation of the Defense Waste Processing Facility (DWPF) Vitrification Building (S-Canyon). This paper will provide an overview of the nature of lightning and the principals of lightning protection. This will provide the reader with a basic understanding of the phenomena of lighting and its potential for damaging structures, components, and injuring personnel in or near the structure.

  7. Seminar for National Lightning Protection and Standardization Held in Chengdu,Sichuan

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ Seminar for National Lightning Protection and Standardization was held in Chengdu of Sichuan province in China on July 30-31. It was sponsored by the Chinese National Technical Committee for Lightning Protection Standardization and was organized by ZhongGuang High-tech Industrial Development Co.,Ltd. About 70 participants engaged in R&D, management and education of lightning protection technology and in design, manufacturing, test of lightning protection products from different industries, such as railway, telecommunication, meteorology, traffic, construction etc, attended the seminar. Prof. LuChonghui, Mr. Wang Deyan and Prof. He Jinliang presided it respectively, who are the chairman and vice chairmen of the committee. Mr. Ma Lincong,secretary-general of China Association for Standardization, made the opening address.

  8. Design of Lightning Arresters for Electrical Power Systems Protection

    Directory of Open Access Journals (Sweden)

    Shehab Abdulwadood

    2013-01-01

    Full Text Available This paper presents an overview of how the lightning strikes and their effects on power distribution systems can be modeled, where the results give a clear picture of how to eliminate the devastating impact, caused by lightning, by using lightning arresters. The program ATP-Draw (Alternative Transient Program was used to simulate the problem and was applied on a part of a power network.The simulation was done once when the lightning strikes a transmission line and a substation with no lightning arresters in use and once more with their use. The source of the lightning was represented by the ATP models (Type-15 surge function and Type-13 ramp function and the surge arrester was represented by the MOV-Type 92 component. The voltage was recorded at the substation 110/22 kV and at all loads in the electric network, and was drawn by the PlotXWin program. The results obtained indicate that the voltages induced by the lightning can reach values of the order of millions over insulation flashover levels for 22 kV equipment, where is clearly seen in Fig. 12 to 16 and Tab.10, which requires the installation of lightning arresters.

  9. Lightning Protection Performance Assessment of Transmission Line Based on ATP model Automatic Generation

    Directory of Open Access Journals (Sweden)

    Luo Hanwu

    2016-01-01

    Full Text Available This paper presents a novel method to solve the initial lightning breakdown current by combing ATP and MATLAB simulation software effectively, with the aims to evaluate the lightning protection performance of transmission line. Firstly, the executable ATP simulation model is generated automatically according to the required information such as power source parameters, tower parameters, overhead line parameters, grounding resistance and lightning current parameters, etc. through an interface program coded by MATLAB. Then, the data are extracted from the generated LIS files which can be obtained by executing the ATP simulation model, the occurrence of transmission lie breakdown can be determined by the relative data in LIS file. The lightning current amplitude should be reduced when the breakdown occurs, and vice the verse. Thus the initial lightning breakdown current of a transmission line with given parameters can be determined accurately by continuously changing the lightning current amplitude, which is realized by a loop computing algorithm that is coded by MATLAB software. The method proposed in this paper can generate the ATP simulation program automatically, and facilitates the lightning protection performance assessment of transmission line.

  10. Protection characteristics of a Faraday cage compromised by lightning burnthrough.

    Energy Technology Data Exchange (ETDEWEB)

    Warne, Larry Kevin; Bystrom, Edward; Jorgenson, Roy Eberhardt; Montoya, Sandra L.; Merewether, Kimball O.; Coats, Rebecca Sue; Martinez, Leonard E.; Jojola, John M.

    2012-01-01

    A lightning flash consists of multiple, high-amplitude but short duration return strokes. Between the return strokes is a lower amplitude, continuing current which flows for longer duration. If the walls of a Faraday cage are made of thin enough metal, the continuing current can melt a hole through the metal in a process called burnthrough. A subsequent return stroke can couple energy through this newly-formed hole. This LDRD is a study of the protection provided by a Faraday cage when it has been compromised by burnthrough. We initially repeated some previous experiments and expanded on them in terms of scope and diagnostics to form a knowledge baseline of the coupling phenomena. We then used a combination of experiment, analysis and numerical modeling to study four coupling mechanisms: indirect electric field coupling, indirect magnetic field coupling, conduction through plasma and breakdown through the hole. We discovered voltages higher than those encountered in the previous set of experiments (on the order of several hundreds of volts).

  11. 采用架空接闪线的防直击雷设计%Direct Lightning Protection Design of Overhead Lightning Line

    Institute of Scientific and Technical Information of China (English)

    黄旭; 李红旭

    2015-01-01

    Based on an example of a building,this paper introduced the lightning protection design of a certain first-class direct lighting protection buildings.The different layouts of adopting single lightning rod and single overhead lightning conductor were calculated and contrasted,and ultimately a plan which uses several overhead lightning conductors was confirmed.During the comparison,the protective range and its difference between dual overhead lightning conductors and designed specifications of lightning protection were analyzed.Finally,the rolling ball method was adopted to do the checking computation of the final plan,which confirms that it can play a role in direct lightning protection.%以某厂房为例,介绍了一类防雷建筑物的防直击雷设计。计算比较了独立接闪杆、架空接闪线的几种不同布置方式,并确定一种数根架空接闪线的方案。在方案比较中,着重分析了双架空接闪线的保护范围及其与防雷设计规范中的不同。采用滚球法对最终方案进行了防雷验算,确认其能起到防直击雷的作用。

  12. Electrically conductive carbon fibre-reinforced composite for aircraft lightning strike protection

    Science.gov (United States)

    Katunin, Andrzej; Krukiewicz, Katarzyna; Turczyn, Roman; Sul, Przemysław; Bilewicz, Marcin

    2017-05-01

    Aircraft elements, especially elements of exterior fuselage, are subjected to damage caused by lightning strikes. Due to the fact that these elements are manufactured from polymeric composites in modern aircraft, and thus, they cannot conduct electrical charges, the lightning strikes cause burnouts in composite structures. Therefore, the effective lightning strike protection for such structures is highly desired. The solution presented in this paper is based on application of organic conductive fillers in the form of intrinsically conducting polymers and carbon fabric in order to ensure electrical conductivity of whole composite and simultaneously retain superior mechanical properties. The presented studies cover synthesis and manufacturing of the electrically conductive composite as well as its characterization with respect to mechanical and electrical properties. The performed studies indicate that the proposed material can be potentially considered as a constructional material for aircraft industry, which characterizes by good operational properties and low cost of manufacturing with respect to current lightning strike protection materials solutions.

  13. Lightning, surge and transient protection. Citations from the NTIS data base

    Science.gov (United States)

    Reed, W. E.

    1980-06-01

    Techniques and devices for the protection of electronic and electrical equipment are presented in these Federally sponsored research reports. The citations include research on suppressors, limiters, lightning arresters, electromagnetic pulse protection devices, and overvoltage protection networks. Electromagnetic shielding is excluded. This updated bibliography contains 106 abstracts, 44 of which are new entries to the previous edition.

  14. Lightning protection design and testing of an all composite wet wing for the Egrett

    Science.gov (United States)

    Burrows, B. J. C.; Haigh, S. J.; Chessum, C.; Dunkley, V. P.

    1991-01-01

    The Egrett aircraft has an all composite wing comprising CFC(carbon fiber composite)/Nomex sandwich skins, full length CFC main spar caps, and GFRP (glass fiber reinforced plastics) main and auxiliary spar webs. It also has short inboard CFC auxiliary spar caps. It has fine aluminum wires woven into the surface for protection. It has an integral fuel tank using the CFC/Nomex skins as the upper and lower tank walls, and lies between the forward auxiliary spar and the forward of the two main spar webs. The fuel tank is not bagged, i.e., it is in effect a wet wing tank. It has conventional capacitive type fuel gauging. The aircraft was cleared to IFR standards and so required full lightning protection and demonstration that it would survive the lightning environment. The lightning protection was designed for the wing (and also for the remainder of the aircraft). An inner wing test samples (which included a part of the fuel tank) were tested as part of the proving program. The protection design and the testing process are described. The intrinsic structural features are indicated that improve lightning protection design and which therefore minimize the weight and cost of any added lightning protection components.

  15. Manual for lightning protection and earthing. Electrical- and facility engineering. 5. tot. new rev. and enl. ed.; Handbuch fuer Blitzschutz und Erdung. Elektro- und Gebaeudetechnik

    Energy Technology Data Exchange (ETDEWEB)

    Hasse, P.; Wiesinger, J.; Zischank, W.

    2006-07-01

    Recent research and international lightning protection conferences (ICLP) and standardisation committees (IEC) brought about new findings on lightning protection which are considered in this 5th edition. The book outlines the history of lightning research and protection, the development of storm cells and lightning discharges, the incidence of lightning and warning, the electricity characteristics of earthborne lightnings, magnetic lightning fields, the electromagnetic field of the lightning path, the principles and types of lightning protectors, potential equalisation in lightning protection, lightning protection of electric and computer systems, magnetic shields, test methods and generators for lightning protection components and protectors, lightning protection of persons, and legal regulations on lightning protection in Germany. (orig./GL) [German] Aus aktuellen Forschungsergebnissen haben sich ebenso wie aus den internationalen Blitzschutzkonferenzen (ICLP) und Normungsgremien (IEC) neue, weiterfuehrende Aspekte der Blitzschutztechnik ergeben, die in der 5. Auflage dieses Buch ihren Niederschlag gefunden haben. Es befasst sich eingehend mit der Historie der Blitzforschung und des Blitzschutzes, der Entstehung von Gewitterzellen und Blitzentladungen, der Blitzhaufigkeit und Gewitterwarnung, den Stromkennwerten von Erdblitzen, den magnetischen Blitzfeldern, dem elektromagnetischen Feld des Blitzkanals, den Prinzipien des Blitzschutzes, den Fangeinrichtungen, Ableitungen und Erdungen, dem Blitzschutz-Potentialausgleich, dem Blitzschutz elektrischer und informationstechnischer Anlagen, den magnetischen Schirmen, den Pruefverfahren und -generatoren fuer Blitzschutz-Komponenten und -Schutzgeraete, dem Blitzschutz fuer Personen, den Blitzschutzbestimmungen in der Bundesrepublik Deutschland. (orig./GL)

  16. Protecting electronic equipment in composite structures against lightning

    NARCIS (Netherlands)

    Blaj, Mihai Alexandru

    2015-01-01

    Damage resulting from an interaction with lightning current in a military naval vessel, especially in a conflict zone and at the time of a conflict, which leads to the incapacitation of vital activities on the ship, is unacceptable. Because many potential conflict zones are in littoral areas, and be

  17. Lightning protection of ships in maritime and costal environment

    NARCIS (Netherlands)

    Blaj, M.A.; Leferink, Frank Bernardus Johannes

    2009-01-01

    An electromagnetic pulse due to a nearby lightning stroke generates a high intensity magnetic field. Thin metal layers as applied in composite structures cannot shield such a magnetic field. Electronic equipment inside such structures will suffer from high-induced voltages and damage and interferenc

  18. Experimental study of lightning protection effects to a overhead ground wire by a lightning rod and projection rods; Yuraishin oyobi dosshi wo mochiita kakuchisen no raigai boshi ni kansuru jikkenteki kento

    Energy Technology Data Exchange (ETDEWEB)

    Katsuragi, Y. [Chubu Electric Power Co. Inc., Nagoya (Japan); Aihara, Y. [Central Research Institute of Electric Power Industry, Tokyo (Japan)

    1995-04-20

    The overhead ground wire is generally used on transmission lines as one of the lightning protection devices for the power conductors. In recent years, the ground wire with an optical fiber cable in it (OPGW) has been employed on the transmission systems. The strands of the ground wire are, however, frequently melted down because of lightning strokes to them not only in summer but also in winter. For this reason, it is necessary to devise the new lightning protection method for the ground wire. As the protection method, lightning rods installed on the transmission tower arms and projection rods wound around a ground wire are proposed by authors. Lightning protection effects of these methods are shown by model experiments which simulate summer and winter lightning strokes. It has been made clear that these methods are useful as one of the lightning protection methods for transmission lines, and application conditions of them for practical use are also shown. 4 refs., 12 figs., 2 tabs.

  19. Lightning protection for roof-mounted solar cell using two masts

    Directory of Open Access Journals (Sweden)

    N. Petcharaks

    2013-03-01

    Full Text Available Houses invested in roof-mounted solar cell need protection from direct lightning. This paper presents the application of numerical method in designing the height and location of masts based on protection angle method according to international standard IEC 62305. An isolated external lightning protection system using two isolated masts is designed. The protected zone which is in the volume according to the protection angle method, depends on the protection level, the rolling sphere radius and the height of the masts which must be less than the rolling sphere radius defined in IEC standard. Furthermore, separation distance between the protected house and mast depends on the height of the mast. This paper develops a program using heuristic numerical method to design masts to protect a house with roof-mounted solar cell. Input data such as the house dimensions and the lightning protection class should be provided. This program is tested on houses with different dimensions. The height and location of two masts are obtained. The numerical results show that this program can be used effectively and correctly.

  20. 30 CFR 57.12069 - Lightning protection for telephone wires and ungrounded conductors.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Lightning protection for telephone wires and ungrounded conductors. 57.12069 Section 57.12069 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... ungrounded conductors. Each ungrounded conductor or telephone wire that leads underground and is...

  1. 30 CFR 56.12069 - Lightning protection for telephone wires and ungrounded conductors.

    Science.gov (United States)

    2010-07-01

    ... ungrounded conductors. 56.12069 Section 56.12069 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... NONMETAL MINES Electricity § 56.12069 Lightning protection for telephone wires and ungrounded conductors. Each ungrounded power conductor or telephone wire that leads underground and is directly exposed...

  2. Evaluation of the protection of rural lines transformers against lightning discharges

    Energy Technology Data Exchange (ETDEWEB)

    Mello, Darcy Ramalho de; Oliveira, Ana Angelica da Silva; Medeiros, Carmem Polycarpo; Rodrigues, Jose Antonio P. [Centro de Pesquisas de Energia Eletrica (CEPEL), Nova Iguacu, RJ (Brazil)], Emails: darcy@cepel.br, aaso@cepel.br, carmem@cepel.br, japr@cepel.br

    2007-07-01

    This article describe the tests made in order to evaluate the efficacy and the limitations of several methods used to protect 15 kV and 34.5 kV rural lines transformers against lightning discharges. The results obtained showed that the equipment used in the H V side of the transformers offer a good protection against lightning but, high values of the reflected voltage at the secondary side of the transformers were measured and the use of low voltage arresters, from several manufacturers, do not present a good result for the consumer. Due to the results obtained with the protections, an evaluation of the response frequency curve of the transformer was made. The results showed that is necessary to develop a new project for the transformers or a new protection for the low voltage side of the actual transformers to protect the consumer. (author)

  3. Studying energy evolution in the discharge chamber of a multichamber lightning protection system

    Science.gov (United States)

    Pinchuk, M. E.; Budin, A. V.; Kumkova, I. I.; Chusov, A. N.

    2016-04-01

    We present experimental data on the distribution of energy deposition along the discharge chamber of a multichamber lightning protection system at the initial stage of a discharge process modeling a lightning current pulse with 10 kA amplitude. The multichamber system comprised serially connected gas-discharge chambers. The breakdown between electrodes situated on the bottom of a channel in each chamber induces the formation of a shock wave. Subsequent energy evolution during the development of discharge proceeds in the entire volume bounded by the shock wave.

  4. Interception efficiency of CVM-based lightning protection systems for buildings and the fractional Poisson model

    CERN Document Server

    Haller, Harold S

    2016-01-01

    The purpose of this paper is to resolve a question regarding efficiency of a lightning protection system (LPS) for buildings based on the collection volume method (CVM) . The paper has two components. The first, following suggestions of other authors [Abidin and Ibrahim 2004], takes advantage of count data from installed devices, and independent installation-site inspections to develop our statistical analysis. The second component investigates the validity of the underlying theory by introducing a novel methodology of fractional Poisson processes, which are able to reproduce the burstiness of lightning strikes, an essential feature of stochastic time dependence of incidence of lightning strikes. The standard Poisson processes used in the past efforts in this area cannot do that.

  5. Concept of a Conducting Composite Material for Lightning Strike Protection

    Directory of Open Access Journals (Sweden)

    Katunin A.

    2016-06-01

    Full Text Available The paper focuses on development of a multifunctional material which allows conducting of electrical current and simultaneously holds mechanical properties of a polymeric composite. Such material could be applied for exterior fuselage elements of an aircraft in order to minimize damage occurring during lightning strikes. The concept introduced in this paper is presented from the points of view of various scientific disciplines including materials science, chemistry, structural physics and mechanical engineering with a discussion on results achieved to-date and further plans of research.

  6. Protection against lightning and surges in photovoltaic installations; Protecao contra descargas atmosfericas e surtos em instalacoes fotovoltaicas

    Energy Technology Data Exchange (ETDEWEB)

    Schultz, Brigitte [Siemens AG (Germany); Wettingfeld, Juergen [W. Wettingfeld GmbH (Germany)

    2010-09-15

    Besides damaging in the photovoltaic panels, lightning can also involve electronic equipment through cables that penetrate in buildings. A supplement for photovoltaic systems located on the roof of buildings was published by the German standardization committees in order to integrate them into lightning protection. In this paper, it is analyzed the requirements of the standards and application case studies.

  7. Research on Protection against Lightning for Roof Fixture%屋顶固定物防雷击研究

    Institute of Scientific and Technical Information of China (English)

    洪友白

    2013-01-01

    I n th is paper, the incorrect design of connecting roof fixture to lightning protection device without considering any lightning protection premise is analyzed and corrected; the standard IEC 62305 - 3:2010 Edition 2. 0 Protection against Lightning -Part 3:Physical Damage to Structures and Life Hazard has been studied so as to understand whether or not the roof fixture needs to be protected against lightning or connected to lightning protection device, as well as the basis part terms of GB 50057-2010 Code for Design Protection of Structures against Lightning.%针对屋顶固定物不考虑任何防雷击前提而与防雷装置相连的错误设计进行剖析和纠正,研读 IEC 62305-3:2010 Edition 2.0《Protection against Lightning -Part 3: Physical Damage to Struc-tures and Life Hazard》标准,理解屋顶固定物要不要防雷击、要不要与防雷装置连接及其原因,以及GB 50057-2010《建筑物防雷设计规范》部分条款的依据所在。

  8. Demonstration project of rural lightning protection%浅淡农村防雷示范工程工作

    Institute of Scientific and Technical Information of China (English)

    韦翔; 姚志东; 王春丽

    2011-01-01

    Demonstra and lightning safety lightning protection lightning shelter for tion project of rual lightning protection includes:installation of electroni warning signs to transfer meteorological information, lightning approac knowledge; installation of lightning protection tower villager; improvement of lightning protection facilities as village committee, houses and factories efficiency antenna, of lightning school, farm produce market; installation of lightnin easily attacked protection line and solar water heater by lightning; installation E; taking lightning protec c display hing and and gloriette to provide of public buildings, such g protection facilities for SPD for great value of interception tion measures on TV antenna, satellite%农村(示范村)防雷工程主要包括:安装电子显示屏和防雷击安全警示牌,为村民传递气象信息、预警雷电临近、宣传防雷知识;安装避雷铁塔、避雷亭,为村民提供避雷场所;完善村委会、学校、农贸市场等公共建筑物的防雷设施;雷电灾害风险值大的民房、厂房的防雷装置安装;对防雷装置拦截效率E值大的线路安装SPD;对电视天线、卫星天线、太阳能热水器采取防雷措施等。

  9. How to verify lightning protection efficiency for electrical systems? Testing procedures and practical applications

    Energy Technology Data Exchange (ETDEWEB)

    Birkl, Josef; Zahlmann, Peter [DEHN and SOEHNE, Neumarkt (Germany)], Emails: Josef.Birkl@technik.dehn.de, Peter.Zahlmann@technik.dehn.de

    2007-07-01

    There are increasing numbers of applications, installing Surge Protective Devices (SPDs), through which partial lightning currents flow, and highly sensitive, electronic devices to be protected closely next to each other due to the design of electric distribution systems and switchgear installations which is getting more and more compact. In these cases, the protective function of the SPDs has to be co-ordinated with the individual immunity of the equipment against energetic, conductive impulse voltages and impulse currents. In order to verify the immunity against partial lightning currents of the complete system laboratory tests on a system level are a suitable approach. The proposed test schemes for complete systems have been successfully performed on various applications. Examples will be presented. (author)

  10. Synthesis and testing of a conducting polymeric composite material for lightning strike protection applications

    Science.gov (United States)

    Katunin, A.; Krukiewicz, K.; Turczyn, R.; Sul, P.; Łasica, A.; Catalanotti, G.; Bilewicz, M.

    2017-02-01

    Lightning strike protection is one of the important issues in the modern maintenance problems of aircraft. This is due to a fact that the most of exterior elements of modern aircraft is manufactured from polymeric composites which are characterized by isolating electrical properties, and thus cannot carry the giant electrical charge when the lightning strikes. This causes serious damage of an aircraft structure and necessity of repairs and tests before returning a vehicle to operation. In order to overcome this problem, usually metallic meshes are immersed in the polymeric elements. This approach is quite effective, but increases a mass of an aircraft and significantly complicates the manufacturing process. The approach proposed by the authors is based on a mixture of conducting and dielectric polymers. Numerous modeling studies which are based on percolation clustering using kinetic Monte Carlo methods, finite element modeling of electrical and mechanical properties, and preliminary experimental studies, allow achieving an optimal content of conducting particles in a dielectric matrix in order to achieve possibly the best electrical conductivity and mechanical properties, simultaneously. After manufacturing the samples with optimal content of a conducting polymer, mechanical and electrical characterization as well as high-voltage testing was performed. The application of such a material simplifies manufacturing process and ensures unique properties of aircraft structures, which allows for minimizing damage after lightning strike, as well as provide electrical bounding and grounding, interference shielding, etc. The proposed solution can minimize costs of repair, testing and certification of aircraft structures damaged by lightning strikes.

  11. 基于IEC62305避雷针最大保护角法防雷效果分析%Analysis of Lightning Protection Effect Based on Lightning Rod Maximum Protection Angle in IEC 62305

    Institute of Scientific and Technical Information of China (English)

    李家启; 王代新; 江孟蜀

    2012-01-01

    针对闪电对地物发生闪击的瞬间状态,采用库仑定律重点分析研究IEC62305推荐的避雷针最大保护角法的雷电防护效果.结果表明:IEC62305推荐的避雷针最大保护角,其保护域内不仅可免遭雷电正击,还可免遭雷电侧击;而GBJ57推荐的最大保护角保护域内仅可免遭雷电正击.基于此,为GB50057采用IEC62305推荐最大保护角而不继续采用GBJ57推荐最大保护角提供了理论支撑和科学依据.%Aiming at the instantaneous state of the cloud-ground lightning and using the Coulomb's law, we analyze the lightning protection effect in this study based on the lightning rod maximum protection an gle in IEC 62305. The result shows that the lightning rod maximum protection angle recommended by IEC 62305 can not only protect direct-strike lightning but also flank striking lightning, while the maximum protection angle recommended by GBJ57 can only protect direct-strike lightning, thus providing a theoreti- cal support and a scientific basis for the adoption of the maximum protection angle recommended by IEC 62305 instead of that by GBJ57 in GB50057.

  12. Effectiveness of Lightning Protection Devices%雷电保护装置的有效性研究

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In addition to the conventional Franklin Rod, many non-conventional air terminals are being used as lightning protection devices. As cited in previous works, these non-conventional devices emit space charge in the vicinity of the terminals during the process of lightning stroke. A number of factors affect the performance of these lightning protection devices, among them are geometry and dimension of the devices, location of the device above the ground, height of the cloud above the ground, and polarity of the lightning stroke. The performance of these lightning protection devices has been a topic of discussion by researchers for many years. Some studies focused on the magnitude of emission current from these devices as a criterion to evaluate their performances. The critical flashover voltage (CFO) between the devices and a metal screen simulating cloud can also be used as another criterion to evaluate the performance of the devices. Laboratory measurements were conducted in controlled conditions on different types of lightning protection devices to compare their performance. Four different types of devices were used in the present study:Franklin Rod, TerraStat models TS 100, TS 400, and Spline Ball Ionizer. The study focused on the CFO voltage of the air gap between devices and the metal screen. The CFO voltage was evaluated using standard switching and lightning impulses. The measurements were recorded for positive as well as negative polarity. The air gap between the devices and metal screen was selected at 2 m and 3 m. The results obtained provide a better understanding of the electrical performance of lightning protection devices.

  13. Modeling and Simulation of the Current Quenching Behavior of a Line Lightning Protection Device

    CERN Document Server

    Mürmann, Mario; Fuchs, Roman; Nefedov, Alexander; Nordborg, Henrik

    2016-01-01

    We develop a consistent model for a Line Lightning Protection Device and demonstrate that this model can explain the two modes of current quenching -- impulse quenching and current zero quenching -- observed in such devices. A dimensional analysis shows that impulse quenching can always be obtained if the power loss from the electric arcs is large enough as compared to $U_0 I_f$, where $U_0$ is the grid voltage and $I_f$ is the maximum follow current after a lightning strike. We further show that the two modes of quenching can be reproduced in a full 3D arc simulations coupled to the appropriate circuit model. This means the arc simulations can be used for optimization and development of future LLPDs.

  14. Research on New Airworthiness Requirements of Lightning Protection for Civil Aircraft Fuel Tank Explosion Prevention%民机燃油箱防爆闪电防护新适航要求研究

    Institute of Scientific and Technical Information of China (English)

    张斌; 岳鹏; 薛勇; 周宇穗

    2015-01-01

    民用飞机燃油箱系统防爆设计是飞机设计的一个重要方面,其中适航对燃油箱系统闪电防护设计要求作为燃油箱防爆设计及验证的一个重要组成部分,历来受到航空工业界及美国联邦航空局( FAA )的普遍关注.通过研究FAA关于民用飞机燃油箱系统防爆方面闪电防护的最新适航要求,总结了相关条款的变化内容及相应的符合性验证方法,并预判了未来航空工业界由此产生的影响,对民用飞机适航验证有一定借鉴意义.%Fuel tank system explosion prevention of civil aircraft is an important part of aircraft design, and air-worthiness requirements lightning protection regulatory for fuel tank system as an important part of fuel tank explo-sion proof design and validation, has attracted widespread attention in the aviation industry and Federal Aviation Administration( FAA) . This paper studies the latest FAA lightning protection airworthiness requirements of civil aircraft fuel tank system, summarized the evolution of the corresponding provisions and compliance validation meth-od, and also predicted the future effect on aviation industry. The results show the method can provide useful refer-ence for the civil aircraft airworthiness certification.

  15. Designing an Optimal Lightning Protection Scheme for Substations Using Shielding Wires

    Directory of Open Access Journals (Sweden)

    A. Khodadadi

    2017-06-01

    Full Text Available An optimal lightning protection scheme for a substation using shielding wires is investigated in this paper through computer software analysis. An economic approach is utilized by choosing a reasonable trade-off between protection, the number of shielding wires and the heights of them from the ground. This study is initially applied to a simple two-wire system and then extended to a sample substation. The solution for each problem is executed in MATLAB and 3-D realization is shown.

  16. Lightning Protection and Structural Bonding for the B2 Test Stand

    Science.gov (United States)

    Kinard, Brandon

    2015-01-01

    With the privatization of the space industry, NASA has entered a new era. To explore deeper parts of the solar system, NASA is developing a new spacecraft, the Space Launch System (SLS), capable of reaching these destinations, such as an asteroid or Mars. However, the test stand that is capable of testing the stage has been unused for many years. In addition to the updating/repair of the stand, more steel is being added to fully support the SLS. With all these modifications, the lightning protection system must be brought up to code to assure the protection of all personnel and assets. Structural bonding is a part of the lightning protection system. The focus of this project was to assure proper structural bonding. To begin, all relevant technical standards and the construction specifications were reviewed. This included both the specifications for the lightning protection and for general construction. The drawings were reviewed as well. From the drawings, bolted structural joints were reviewed to determine whether bonding was necessary. Several bolted joints were determined to need bonding according to the notes in the drawings. This exceeds the industry standards. The bolted joints are an electrically continuous joint. During tests, the stand experiences heavy vibration that may weaken the continuity of the bolted joint. Therefore, the secondary bonding is implemented to ensure that the structural joint has low resistance. If the structural joint has a high resistance because of corrosion, a potential gradient can occur that can cause a side flash. Damage, injury, or death can occur from a side flash so they are to be prevented. A list of the identified structural joints was compiled and sent to the contractor to be bonded. That covers the scope of this project.

  17. Corona discharges from a windmill and its lightning protection tower in winter thunderstorms

    Science.gov (United States)

    Wu, Ting; Wang, Daohong; Rison, William; Thomas, Ronald J.; Edens, Harald E.; Takagi, Nobuyuki; Krehbiel, Paul R.

    2017-05-01

    This paper presents lightning mapping array (LMA) observations of corona discharges from a windmill and its lightning protection tower in winter thunderstorms in Japan. Corona discharges from the windmill, called windmill coronas, and those from the tower, called tower coronas, are distinctly different. Windmill coronas occur with periodic bursts, generally radiate larger power, and possibly develop to higher altitudes than tower coronas do. A strong negative electric field is necessary for the frequent production of tower coronas but is not apparently related with windmill coronas. These differences are due to the periodic rotation of the windmill and the moving blades which can escape space charges produced by corona discharges and sustain a large local electric field. The production period of windmill coronas is related with the rotation period of the windmill. Surprisingly, for one rotation of the windmill, only two out of the three blades produce detectable discharges and source powers of discharges from these two blades are different. The reason for this phenomenon is still unclear. For tower coronas, the source rate can get very high only when there is a strong negative electric field, and the source power can get very high only when the source rate is very low. The relationship between corona discharges and lightning flashes is investigated. There is no direct evidence that corona discharges can increase the chance of upward leader initiation, but nearby lightning flashes can increase the source rate of corona discharges right after the flashes. The peak of the source height distribution of corona discharges is about 100 m higher than the top of the windmill and the top of the tower. Possible reasons for this result are discussed.

  18. Lightning Protection Design of Ammunition Warehouse%某弹药库房防雷设计方案

    Institute of Scientific and Technical Information of China (English)

    张宝华; 刘振宇; 严凤斌; 林义

    2012-01-01

    Direct lightning stroke, lightning, lightning invasion wave, electrostatic and other protective measures were designed scientifically through field investigation and reasonable terms against high risk for the treasury vulnerable to lightning. The specific implementation plan was developed. The purpose was to provide technical guidance and reference for safety of the warehouse.%针对弹药库房危险性高、易受雷击等特点,笔者通过实地勘测,合理计算,科学地设计了直击雷、感应雷、雷电波侵入、静电等防护措施,并制定了具体的实施方案,对仓库的安全工作有一定的技术指导和借鉴作用.

  19. Reduction of the visual impact of overhead transmission line systems through utilisation of line surge arresters as lightning protection

    DEFF Research Database (Denmark)

    Sørensen, Thomas Kjærsgaard; Holbøll, Joachim

    2008-01-01

    in line performance and lightning protection of the nearest substations requires thorough modelling of the new line including all electrical parameters necessary for performance evaluation under all conditions. In this paper, explicit use of line surge arresters as lightning protection on the line...... of the line and the required protection level in substations. The use of line surge arresters gives the possibility to decrease the height of towers thereby improving the visual impression of the overhead line transmission systems. However the usage of line surge arresters will, dependent upon line surge...

  20. Lightning protection guidelines and test data for adhesively bonded aircraft structures

    Science.gov (United States)

    Pryzby, J. E.; Plumer, J. A.

    1984-01-01

    The highly competitive marketplace and increasing cost of energy has motivated manufacturers of general aviation aircraft to utilize composite materials and metal-to-metal bonding in place of conventional fasteners and rivets to reduce weight, obtain smoother outside surfaces and reduce drag. The purpose of this program is protection of these new structures from hazardous lightning effects. The program began with a survey of advance-technology materials and fabrication methods under consideration for future designs. Sub-element specimens were subjected to simulated lightning voltages and currents. Measurements of bond line voltages, electrical sparking, and mechanical strength degradation were made to comprise a data base of electrical properties for new technology materials and basic structural configurations. The second hase of the program involved tests on full scale wing structures which contained integral fuel tanks and which were representative of examples of new technology structures and fuel systems. The purpose of these tests was to provide a comparison between full scale structural measurements and those obtained from the sub-element specimens.

  1. Frequency domain model for transient analysis of lightning protection systems of buildings.

    Science.gov (United States)

    Gómez, Pablo

    2016-10-01

    A frequency domain modeling approach for lightning protection systems (LPS) of buildings is described and validated in this paper. The model is based on a 2-port transmission line representation of each conductor, and the further assembling of a network representing the complete structure. Horizontal and vertical conductors are modeled using formulas based on the complex images method, in order to take into account frequency dependence. Variation of electrical parameters with height is also considered for vertical conductors. This is accomplished by means of a non-uniform modeling approach based on conductor subdivision and cascaded connection of chain matrices computed for each segment. The results from the model are validated by means of comparisons with measurements reported elsewhere, as well as simulations using PSCAD/EMTDC.

  2. 水质自动监测站综合防雷技术研究%Research on Integrated Lightning Protection Technology of Automatic Water Quality Monitoring Station

    Institute of Scientific and Technical Information of China (English)

    樊希彬; 于淼; 梁铁军

    2011-01-01

    基于建筑物雷击风险评估方法,得出本地可能遭受到的雷击形式和雷电破坏电子设备途径.以鸭绿江丹东江桥水质自动监测站综合防雷系统工程设计与施工为基础,对水质自动监测站外部、内部综合防雷技术体系进行阐述,通过现代防雷技术方法,有效降低监测设备因雷击而产生的故障率、最大限度预防和减少雷击所发生的人身伤亡和国家财产损失.%According to the method of building lightning risk assessment, ways of local lightning and means that lightning damages to electronic devices are obtained. Based on the design and construction of integrated lightning protection system of Yalu River automatic water quality monitoring stations in Dandong, external and internal integrated lightning protection system of automatic water quality monitoring stations is illustrated. Through methods of modern lightning protection technology, the failure rate generated from monitoring equipment stuck by lightning can be effectively reduced, the body injuries, deaths and the loss of state property led by lightning can be maximally prevented and reduced.

  3. 高速铁路避雷器与防雷线技术综合应用研究%Integrated Research on Application of Technology of Lightning Arrester and Lightning Protection Rod in High-speed Railway System

    Institute of Scientific and Technical Information of China (English)

    孙巍

    2016-01-01

    In China,high-speed railways,in most cases,are to take path through diverse landform,topography where differed geography,climate and operational conditions at varied areas would make lightning protection even tougher for the development of high-speed railways,but what even more challenging is that the technology of lightning arrester and lightning protection rod are still self-deficient.Thus,any separate use of certain lightning protection technology can hardly help to achieve technological promotion of lightning arrestment and lightning protection in high-speed railways, optimally.It is constructively rendered a conformation in this article that at all the sections where high-speed railways are to travel through,lightning arrester and lightning protection rod as a set of comprehensive engineering system can be applied to high-speed railway catenary,which designed to make the entire lines subject to overall protection and control under a system of lightning arrestment and lightning protection and therefore,to form an organic combination and reciprocal advantage between these two mature technologies.As attested by certain researches,at the geographic locations where are allocated with mountainous areas,areas with a varied topography and specially distributed landform, catenary onto high-speed railways is primarily being furnished with lightning arrester meanwhile at the geographic locations where intense lightning/thunderstorm being likely distributed,topography flat and main electrical equipment installed,erection of lightning arrestment rod would be empirical.These two afore said means would have to account for differed topographic areas,intended to form full coverage of lightning arrestment and lightning protection,and thus,to effectively secure safety of high-speed railway lines and facilities.%我国高速铁路线路大多要经过多种地形、地貌,不同区域地理、气候、运行条件的差异增加了高速铁路防范雷击的难度,且避雷

  4. Lightning hazards overview: Aviation requirements and interests

    Science.gov (United States)

    Corn, P. B.

    1979-01-01

    A ten-year history of USAF lightning incidents is presented along with a discussion of the problems posed by lightning to current aircraft, and the hazards it constitutes to the electrical and electronic subsystems of new technology aircraft. Lightning technical protection technical needs, both engineering and operational, include: (1) in-flight data on lightning electrical parameters; (2) tech base and guidelines for protection of advanced systems and structures; (3) improved laboratory test techniques; (4) analysis techniques for predicting induced effects; (5) lightning strike incident data from general aviation; (6) lightning detection systems; (7) pilot reports on lightning strikes; and (8) better training in lightning awareness.

  5. 现代智能建筑电子系统防雷技术浅析%The modern intelligent building electrical system lightning protection technology is analysed

    Institute of Scientific and Technical Information of China (English)

    徐国栋; 窦坤; 董东; 董永红

    2015-01-01

    现代智能建筑电子系统防雷包括直击雷和雷电感应防护,既要考虑雷电来自电路的侵入又要考虑来自磁场的干扰,既要拦截来自带电线路的雷电危害又要考虑非带电金属体的反击,为此综合提出屋面直击雷、电源、信号线缆防护等全方位防雷方案,供同行参考.%Lightning protection of modern electronic systems, inteligent buildings including direct lightning and thunder and lightning induction protection, should not only consider the thunder from the invasion of the circuit and to consider from the interference of magnetic field, both to intercept from live line lightning harm and to consider the charged metal body, this paper provides comprehensive roof lightning, power supply, signal cable protection, such as comprehensive lightning protection scheme, for the coleague reference.

  6. Hydro-Quebec TransEnergie's perspective on overhead transmission line protection against lightning

    Energy Technology Data Exchange (ETDEWEB)

    Dutil, A. [Hydro-Quebec, Montreal, PQ (Canada). TransEnergie Div.

    2006-07-01

    Hydro-Quebec TransEnergie's interest in transmission line surge arresters (TLSA) was discussed. The utility conducted studies regarding the use of TLSAs to reduce outages caused by lightning in overhead transmission lines having voltages of 52 to 330 kV. It was determined that in some cases, TLSA is the only solution to reducing flashover initiated by lightning. This paper presented the results of 4 different TLSA configurations in which the impact of grounding resistance on TLSA performance was examined in an effort to determine the most effective configuration. The study revealed that lightning flashovers could be reduced by 70 per cent by installing 1 TLSA on every 2 poles of a 52 kV transmission line. The TLSA should be mounted on one pole structure and the earth wire on the unprotected poles should be removed. According to several tests conducted at Hydro-Quebec's Institut de Recherche en Electricite du Quebec (IREQ), the energy absorption capability of arresters from 4 different manufacturers proved to be at least 6 kJ/kv. The arresters failure rate was estimated to 3 per cent every time a lightning strike occurred on a transmission line. It was suggested that a 100 km long line with one pole every 60 meters should not have more than one arrester failure per year. The arresters must be installed with a mechanical device that could disconnect a failed unit from the transmission system to avoid a permanent fault on the network. It was concluded that TLSAs are useful in reducing lightning flashovers caused by lightning. However, Hydro-Quebec TransEnergie still has concerns regarding their cost, reliability, impact on line maintenance, testing difficulties in the field, mechanical stress on the conductors, and their ability to withstand dielectric behaviour under ice. tabs., figs.

  7. Protection of ± 500 kV HVDC Double-circuit Converter Station from Lightning Induced Overvoltage

    Institute of Scientific and Technical Information of China (English)

    DONG Manling; YUAN Zhiyong; LI Tianwei; ZHAO Xiangen; ZHANG Jiaxin; HE Junjia

    2013-01-01

    In order to obtain reasonable schemes of arrester in converter stations,the arrester scheme of"Xiluodu-Guangdong HVDC ±500 kV double circuit transmission" project against lighting induced overvoltage,which was designed according to the main principle of lightning protection in converter station,is discussed.A calculation of the lighting induced overvoltage in Zhaotong converter station under various operation modes is performed with ATP-EMTP software,then the surge arrester configuration of the converter station is decided,and the arrester protection schemes of smoothing reactor and neutral line are studied.It is concluded that additional protection is necessary because of the relatively large gap between protected disconnecting switch and arrester of metallic return transfer bus.Plus,the smoothing reactor (SR) arrester near the valve hall could be removed to improve the scheme's economic performance.

  8. 配电网线路防雷系统的保护研究%Protection Research of Line Lightning Protection System for Distribution Network

    Institute of Scientific and Technical Information of China (English)

    徐航航

    2011-01-01

    Since the complex network structure and low insulation levels for distribution networks. it is easy to lead to lightning accident. And further it will cause power outages and great economic losses. This paper analyzes the principle and the features of lightning protection technology for the powers and the technical program for discribution network is proposed.%由于配电网的网络结构复杂、绝缘水平较低,配电网很容易遭受雷害事故,引起停电事故,从而导致很大的经济损失.本文就电网防雷技术的原理及特点进行分析,并结合实际,提出适用于配电网防雷的技术方案.

  9. Phase Retrieval from Modulus Using Homeomorphic Signal Processing and the Complex Cepstrum: An Algorithm for Lightning Protection Systems

    Energy Technology Data Exchange (ETDEWEB)

    Clark, G A

    2004-06-08

    In general, the Phase Retrieval from Modulus problem is very difficult. In this report, we solve the difficult, but somewhat more tractable case in which we constrain the solution to a minimum phase reconstruction. We exploit the real-and imaginary part sufficiency properties of the Fourier and Hilbert Transforms of causal sequences to develop an algorithm for reconstructing spectral phase given only spectral modulus. The algorithm uses homeomorphic signal processing methods with the complex cepstrum. The formal problem of interest is: Given measurements of only the modulus {vert_bar}H(k){vert_bar} (no phase) of the Discrete Fourier Transform (DFT) of a real, finite-length, stable, causal time domain signal h(n), compute a minimum phase reconstruction {cflx h}(n) of the signal. Then compute the phase of {cflx h}(n) using a DFT, and exploit the result as an estimate of the phase of h(n). The development of the algorithm is quite involved, but the final algorithm and its implementation are very simple. This work was motivated by a Phase Retrieval from Modulus Problem that arose in LLNL Defense Sciences Engineering Division (DSED) projects in lightning protection for buildings. The measurements are limited to modulus-only spectra from a spectrum analyzer. However, it is desired to perform system identification on the building to compute impulse responses and transfer functions that describe the amount of lightning energy that will be transferred from the outside of the building to the inside. This calculation requires knowledge of the entire signals (both modulus and phase). The algorithm and software described in this report are proposed as an approach to phase retrieval that can be used for programmatic needs. This report presents a brief tutorial description of the mathematical problem and the derivation of the phase retrieval algorithm. The efficacy of the theory is demonstrated using simulated signals that meet the assumptions of the algorithm. We see that for

  10. 计算机网络系统的雷电防护研究%A study on lightning protection of computer network system

    Institute of Scientific and Technical Information of China (English)

    周中伟; 周中意; 陈海辉

    2011-01-01

    Taking lightning protection of computer network system as an object of study* the different channels of lightning invade of computer network system was analyzed. According to the characteristic of highly integrated den-sification of electronic components in computer network system! The design ideas about the internal protection and external protection were put forward. In the design, the importance of the internal protection was especially emphasized. Taking into account lightning electromagnetism impulse, the lightning induction and the physical characteristic of the computer network system, the requirements and techniques for lightning protection of the computer network system were emphatically elaborated, and then the lightning protection measures for the computer network system were presented, which have better reference value and maneuverability.%以计算机网络系统雷电防护为研究对象,分析了雷电入侵计算机网络系统的不同途径;针对计算机网络系统电子元件高度集成密集化的特点,提出了内部防雷和外部防雷的设计观点;强调计算机网络系统内部防雷设计的重要性,并结合雷电电磁脉冲、雷电感应及计算机网络系统物理原件组成特征,着重论述计算机网络系统雷电防护的技术性及实践性要求;进而提出了计算机网络系统雷电防护的措施,具有较好的操作性和参考价值.

  11. Simulation Analysis of Lightning Protection Characteristics of Photovoltaic System%光伏系统雷电防护特性仿真分析

    Institute of Scientific and Technical Information of China (English)

    陈坤; 谭进; 吉容佩

    2012-01-01

    由于光伏系统具有面积较大、暴露设备较多且需考虑直击雷防护装置阴影对太阳能电池板的遮挡影响等特点,因此其雷电屏蔽与传统电站存在差异.为更深入地了解光伏系统的雷电防护特性,结合光伏系统结构和雷电侵入途径,采用ATPDraw仿真软件,对光伏阵列及其电气设备进行建模,仿真计算了雷击光伏阵列不同位置、不同雷电流幅值及不同接地电阻情况下光伏阵列的损坏程度和对光伏系统内部设备过电压的影响,并根据计算结果提出了光伏系统雷电防护的重点.%photovoltaic system has characteristics, such as large area, many exposed device and the impact of direct lightning protection device shadows on the shelter of solar panels. Therefore, it exist difference between lightning shiel ding for photovoltaic system and conventional power plants. For a better understanding of photovoltaic system lightning protection performance, simulation software ATPDrawiis used to modeling photovoltaic array and electrical equipment by considering photovoltaic system structure and lightning invasion way. Under the conditions of lightning photovoltaic array of different position, different lightning current amplitude and different grounding resistance, it simulates the damaged condition of photovoltaic array and the impact of photovoltaic system internal equipment over-voltage. According to the calculation results, it puts forward the focal point of lightning protection of photovoltaic system.

  12. Discussion on Lightning Protection Measures of Electrification Railway Catenary%电气化铁路接触网防雷措施的探讨

    Institute of Scientific and Technical Information of China (English)

    刘立方

    2013-01-01

      针对国内电气化铁道部分线路遭受雷击较频繁的现状,本文对接触网遭受雷击跳闸情况进行了统计分析,借鉴国外接触网防雷措施,结合我国电气化铁道防雷措施的现状,同时参考国内电气化铁路防雷措施的研究成果,提出了我国电气化铁路接触网系统的防雷措施原则及建议。%Aiming at the situation that the domestic electrified railway line often suffers from lightning, the paper makes a statistical analysis on lightning trip-out times of catenary; combined with foreign catenary lightning protection measures and domestic lightning protection measures of electrification railway, it puts forward the principle and suggestion on lightning protection measures of electrification railway catenary.

  13. 曼型储气柜的防雷接地设计%Lightning Protection & grounding Design of M.A.N Gasholder

    Institute of Scientific and Technical Information of China (English)

    侯彪

    2015-01-01

    That the M.A.N gasholder belongs to the second lightning protection building was clarified, lightning protection parameters and countermeasures introduced, and the reason that the internal piston does not produce and accumulate static electricity has been given as well.%明确了曼型储气柜属于第二类防雷建筑物,介绍了相应的雷电参数和防雷措施,并给出了曼型储气柜内部活塞不会产生和积聚静电的理由。

  14. Lightning in aeronautics

    Science.gov (United States)

    Lago, F.

    2014-11-01

    It is generally accepted that a civilian aircraft is struck, on average, once or twice per year. This number tends to indicate that a lightning strike risk is far from being marginal and so requires that aircraft manufacturers have to demonstrate that their aircraft is protected against lightning. The first generation of aircrafts, which were manufactured mainly in aluminium alloy and had electromechanical and pneumatic controls, had a natural immunity to the effects of lightning. Nowadays, aircraft structures are made primarily with composite materials and flight controls are mostly electronic. This aspect of the "more composite and more electric" aircraft demands to aircraft manufacturers to pay a particular attention to the lightning protection and to its certification by testing and/or analysis. It is therefore essential to take this risk into account when designing the aircraft. Nevertheless, it is currently impossible to reproduce the entire lightning phenomenon in testing laboratories and the best way to analyse the lightning protection is to reproduce its effects. In this context, a number of standards and guides are produced by standards committees to help laboratories and aircraft manufacturers to perform realistic tests. Although the environment of a laboratory is quite different from those of a storm cloud, the rules of aircraft design, the know-how of aircraft manufacturers, the existence of international work leading to a better understanding of the lightning phenomenon and standards more precise, permit, today, to consider the risk as properly controlled.

  15. 古建筑群防雷安全隐患及其对策研究%Study on the Lightning-Protection of Ancient Buildings

    Institute of Scientific and Technical Information of China (English)

    樊希彬; 熊群峰; 夏志刚

    2011-01-01

    By reviewing ancient buildings that were destroyed by lightning strike or fire caused by lightning, lightning protection of ancient buildings was discussed, ancient architectural complex in Dagu Mountain, a provincial-level scenic area of Liaoning, was taken for an example to detect potential safety hazards in lightning-protection of those ancient buildings, 5 types of potential safety hazards were summarized. By studying the classification of ancient buildings'lightning-protection, protection level, lightning-protection measures, design basis of lightningprotection engineering, construction and new construction technology, relevant technical specifications were taken as references for proposing 4 countermeasures against those potential safety hazards from the perspectives of exterior and interior parts of ancient buildings, lightning -protection of ancient trees and so on. In view of actual conditions of the ancient architectural complex in Dagu Mountain, construction plan, personnel placement, labor planning, construction quality control system, acceptance of works, technical documentation and such matters were specifically discussed to give useful support to the future lightning-protection of ancient buildings.%回顾了古建筑被雷电击毁或因雷电引起火灾的历史事件,由此引发了对古建筑群防雷安全问题的探讨,以辽宁省级风景名胜区大孤山古建筑群为例,对古建筑群防雷安全隐患进行勘查和检测,总结出5种防雷安全隐患类型.从古建筑防雷类别划分、保护级别、防雷措施、防雷工程设计依据、工程施工、新施工工艺等6个方面进行研究,依据相应技术规范分别从古建筑物外部、内部和古树木防雷等方面提出4项防雷安全隐患应对措施,并具体针对大孤山古建筑群的实际情况,详细探讨了施工方案、人员安排、劳务计划和施工质量保证体系、工程验收、技术文档等问题,以期为切实做好古建筑

  16. 雷电电磁脉冲防护及 SPD 选择%Lightning Electromagnetic Impulse Protection and SPD Selection

    Institute of Scientific and Technical Information of China (English)

    陈谦

    2016-01-01

    Key points for the protection of lightning electromagnetic impulse are analyzed according to the component features of lightning current. According to relevant documents of various committees of IEC, SPD selection for power inlet of building is discussed and technical progress and work direction of IEC lightning protection committee (TC81 committee) are introduced.%根据雷电流的分量特征,分析雷电电磁脉冲的防护要点。结合IEC各委员会的相关文件,讨论建筑物电源引入处SPD的选择,并介绍IEC雷电防护委员会(TC81委员会)技术进展和工作方向。

  17. 机场空管设备雷电防护%Lightning Protection of Airport Electronic Facilities

    Institute of Scientific and Technical Information of China (English)

    黄裕文; 钟秉武

    2012-01-01

    绵阳南郊机场2004年以来多普勒全向信标/测距仪(DVOR/DME)、仪表着陆系统(ILS)、无向信标机(NDB)、卫星站(TES)、航空气象自动观测系统(AWOS)、甚高频对空电台(VHF)等空管系统设备先后多次发生雷电灾害事故,不同程度地造成了设备故障和工作中断现象,对该机场的飞行保障造成了较为严重的影响.通过对雷灾案例的分析,介绍多级SPD保护,逐级消除雷电残压,同一建筑内设备联合接地和等电位处理,规范综合布线及建立定期维护检测制度,及时排查防雷安全隐患等措施,总结了切实有效解决通信导航设施发生雷电灾害事故的经验和方法.%Since 2004, there occurred lightning accidents many times to airport facilities at Mianyang Airport,such as the Doppler VHF Omnidirectional Radio/Distance Measurement Equipment, Instrument Landing System, No-Directional Beacon, Transportable Earth Stations, Aviation Automated Weather Observing Systems, Very High Frequency radio and so on, which caused equipment failure and work interruptions in different degrees. Through analyzing the lightning cases, some countermeasures are introduced, such as multi-level SPD protection, eliminating lightning residual voltage step by step, integrated grounding and equipotential bonding for all the equipments within the same building, standardizing the generic cabling and establishing the regular maintenance and detection system, checking potential safety hazard timely, etc. Some experiences and effective means to clear up faults in communication and navigation facilities induced by lightning accidents are summarized.

  18. Lightning protection of mobile phone stations in high voltage towers; Blitzschutz bei Mobilfunkstationen auf Mittel- und Hochspannungsmasten. Schutz vor Ueberspannungen

    Energy Technology Data Exchange (ETDEWEB)

    Balzer, G. [TU Darmstadt (Germany); Richter, B. [ABB Hochpannungstechnik, Baden (Switzerland); Schmitt, O. [RWE Net AG, Siegen (Germany)

    2002-12-02

    Transmitter units for mobile phone networks are often installed in existing high voltage towers. In these cases a strict separation of the grounding systems is essential to avoid interferences between the high voltage area and the low voltage energy supply for the mobile phone transmitter station. In order to protect the safety transformer of the mobile phone installation against lightning surges a metall-oxide (MO-) surge arrester is necessary, which furthermore has to withstand the power frequency voltage in case of a single-phase fault in the high voltage power line. For a 110 kV system the power frequency voltage in case of a single-phase short circuit as well as the lightning current stress for a MO-surge arrester is calculated. (orig.) [German] Der weltweit zunehmende Ausbau der Mobilfunknetze erfordert eine grosse Anzahl von Standorten fuer Sende- und Empfangsanlagen. Dabei werden neben neuen Mobilfunkmasten auch Mittel- und Hochspannungsmaste genutzt. Zum Schutz der in den Mobilfunkanlagen eingesetzten Trenntransformatoren gegen moegliche Blitzeinwirkungen werden Metalloxid-Ueberspannungsableiter (MO-Ableiter) eingesetzt. Die Verfasser erlaeutern die geeignete Dimensionierung anhand praktischer Anwendungsbeispiele. (orig.)

  19. Lightning Injuries

    Science.gov (United States)

    ... to electrical equipment or telephone lines inside a house. Lightning can injure a person several ways: Lightning ... a feathering, branching pattern, consist of clusters of tiny pinpoint spots like a cigarette burn, or consist ...

  20. Lightning Protection of Monitored Control System in Oil Depot%油库监控系统的雷电防护

    Institute of Scientific and Technical Information of China (English)

    金炼

    2012-01-01

    Analysis damage and aftermath of lightning strike to oil depot,and analysis prime cause and intrusion path of lightning strike.According to design code for protection of Structures against lightning(GB50057-2010),adopt method of subdivision protection,synthetically protect monitored control system of storage and transportation of oil,security surveillance system and oil control system,to avoid damage of lightning strike because of careless omission.%综合分析雷击对油库造成的损害和后果,以及雷击损害的主要原因和侵入途径,依据《建筑物防雷设计规范》GB50057-2010,采用"分单元防护思想",对油库的储油监控系统、现场安防监控系统、输油控制系统等进行了全面综合防护,防止了因疏漏带来的雷击危害。

  1. Lightning protection for electric utility and industrial applications; Blitzschutz fuer Stromversorgungs- und Industrieanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Benda, S. [ABB EMC Certification AB, Vaesteraas (Sweden)

    1998-10-01

    Lightning strokes generate high interference voltages in industrial plants and high-voltage substations. The characteristics of the transients, the amplitudes of the voltages and their number vary considerably from one network to another. A sound understanding of the phenomena involved and of the implications of certain industry practices are necessary to ensure the safe and reliable operation of the installed electrotechnical equipment. (orig.) [Deutsch] Blitzeinschlaege verursachen in Industrieanlagen und Hochspannungsstationen hohe Stoerspannungen. Die Kennwerte der Ausgleichsspannungen, die Amplituden der Spannungen und deren Anzahl sind von Netz zu Netz verschieden. Um einen sicheren und zuverlaessigen Betrieb der installierten elektrischen Ausruestung sicherzustellen, ist es wichtig, die Phaenomene, die dabei eine Rolle spielen, und die Auswirkungen bestimmter Praktiken in der Industrie gut verstehen. (orig.)

  2. Lightning transient analysis in wind turbine blades

    DEFF Research Database (Denmark)

    Candela Garolera, Anna; Holbøll, Joachim; Madsen, Søren Find

    2013-01-01

    The transient behavior of lightning surges in the lightning protection system of wind turbine blades has been investigated in this paper. The study is based on PSCAD models consisting of electric equivalent circuits with lumped and distributed parameters involving different lightning current...

  3. 昌北雷达站防雷改造工程浅析%Brief Analysis of Lightning Protection Engineering in Changbei Radar Station

    Institute of Scientific and Technical Information of China (English)

    陈浩

    2016-01-01

    Secondary radar is the air traffic controllers "clairvoyance",the normal operation of which is one of the keys to ensure the safety and ordered flight. The position of the secondary radar station is relatively high and isolated, which is very easy to be struck by lightning. Now the lightning accident has become an important factor in the failure of the radar station equipment,so a sound radar station lightning protection system is of great significance. This paper introduces some lightning accidents in Nanchang Changbei Radar Station in recent years,and discusses the problems and treatment methods in the lightning protection engineering.%航管二次雷达是空中交通管制员的“千里眼”,保障其正常运行是保证飞机安全、有序飞行的关键之一。由于二次雷达站所处的位置一般地势相对较高、且孤立,极易遭受雷击,已成为雷达站设备故障停机的一个重要因素,因此做好雷达站的防雷保护系统意义重大。本文介绍了近年来南昌昌北雷达站雷击案例,以及在防雷改造工程施工监督过程中出现的问题及处理方法。

  4. Lightning Phenomenology

    Science.gov (United States)

    Kawasaki, Zen

    This paper presents a phenomenological idea about lightning flash to share the back ground understanding for this special issue. Lightning discharges are one of the terrible phenomena, and Benjamin Franklin has led this natural phenomenon to the stage of scientific investigation. Technical aspects like monitoring and location are also summarized in this article.

  5. 关于特殊仓库易燃易爆场所雷电防护的探讨%Lightning Protection of Special Warehouse and Flammable and Explosive Places

    Institute of Scientific and Technical Information of China (English)

    廖严峰; 秦玉新

    2012-01-01

    Basing on the lightning protection design and the construction of the special warehouses, flammable and explosive places under the new norms, the construction program and the notes of direct lightning and induced lightning were analyzed.%介绍特殊仓库内易燃易爆场所在新规范下如何进行防雷工程的设计与施工,重点针对直击雷与感应雷防护措施的施工方案及施工要点进行分析。

  6. Protection Method of Biological Lightning Safety around Power Grid Based on Grounding Electrode Structure

    Science.gov (United States)

    Sixiang, Chen; Daopin, Chen; Ming, Zhang; Xiao, Huang; Jian, He; Zhijie, He

    2017-05-01

    Aimed at the actual situation of fish death in fish ponds near the power transmission line towers after the thunderstorm happened in Guangdong Province in China, this paper studied the influence of the ground current on fish in the pond. Firstly, This paper studied the current density of the fish without protection. On this basis, paper studied the horizontal pole with full-shielded, the vertical pole with half-shielded, the horizontal pole with extension three kinds of protective measures and effects. Finally an effective protection scheme was put forward according to the engineering practice. The results can provide some engineering guidance and quantitative basis for the design and modification of grounding devices when the tower is adjacent to the fish ponds in southern China.

  7. The Quality Control Algorithms Used in the Creation of NASA Kennedy Space Center Lightning Protection System Towers Meteorological Database

    Science.gov (United States)

    Orcutt, John M.; Brenton, James C.

    2016-01-01

    An accurate database of meteorological data is essential for designing any aerospace vehicle and for preparing launch commit criteria. Meteorological instrumentation were recently placed on the three Lightning Protection System (LPS) towers at Kennedy Space Center (KSC) launch complex 39B (LC-39B), which provide a unique meteorological dataset existing at the launch complex over an extensive altitude range. Data records of temperature, dew point, relative humidity, wind speed, and wind direction are produced at 40, 78, 116, and 139 m at each tower. The Marshall Space Flight Center Natural Environments Branch (EV44) received an archive that consists of one-minute averaged measurements for the period of record of January 2011 - April 2015. However, before the received database could be used EV44 needed to remove any erroneous data from within the database through a comprehensive quality control (QC) process. The QC process applied to the LPS towers' meteorological data is similar to other QC processes developed by EV44, which were used in the creation of meteorological databases for other towers at KSC. The QC process utilized in this study has been modified specifically for use with the LPS tower database. The QC process first includes a check of each individual sensor. This check includes removing any unrealistic data and checking the temporal consistency of each variable. Next, data from all three sensors at each height are checked against each other, checked against climatology, and checked for sensors that erroneously report a constant value. Then, a vertical consistency check of each variable at each tower is completed. Last, the upwind sensor at each level is selected to minimize the influence of the towers and other structures at LC-39B on the measurements. The selection process for the upwind sensor implemented a study of tower-induced turbulence. This paper describes in detail the QC process, QC results, and the attributes of the LPS towers meteorological

  8. Evaluation of Grounding Impedance of a Complex Lightning Protective System Using Earth Ground Clamp Measurements and ATP Modeling

    Science.gov (United States)

    Mata, Carlos T.; Rakov, V. A.; Mata, Angel G.

    2010-01-01

    A new Lightning Protection System (LPS) was designed and built at Launch Complex 39B (LC39B), at the Kennedy Space Center (KSC), Florida, which consists of a catenary wire system (at a height of about 181 meters above ground level) supported by three insulators installed atop three towers in a triangular configuration. A total of nine downconductors (each about 250 meters long, on average) are connected to the catenary wire system. Each of the nine downconductors is connected to a 7.62-meter radius circular counterpoise conductor with six equally spaced 6-meter long vertical grounding rods. Grounding requirements at LC39B call for all underground and above ground metallic piping, enclosures, raceways, and cable trays, within 7.62 meters of the counterpoise, to be bounded to the counterpoise, which results in a complex interconnected grounding system, given the many metallic piping, raceways, and cable trays that run in multiple direction around LC39B. The complexity of this grounding system makes the fall of potential method, which uses multiple metallic rods or stakes, unsuitable for measuring the grounding impedances of the downconductors. To calculate the downconductors grounding impedance, an Earth Ground Clamp (a stakeless grounding resistance measuring device) and a LPS Alternative Transient Program (ATP) model are used. The Earth Ground Clamp is used to measure the loop impedance plus the grounding impedance of each downconductor and the ATP model is used to calculate the loop impedance of each downconductor circuit. The grounding impedance of the downconductors is then calculated by subtracting the ATP calculated loop impedances from the Earth Ground Clamp measurements.

  9. Aircraft Lightning Electromagnetic Environment Measurement

    Science.gov (United States)

    Ely, Jay J.; Nguyen, Truong X.; Szatkowski, George N.

    2011-01-01

    This paper outlines a NASA project plan for demonstrating a prototype lightning strike measurement system that is suitable for installation onto research aircraft that already operate in thunderstorms. This work builds upon past data from the NASA F106, FAA CV-580, and Transall C-180 flight projects, SAE ARP5412, and the European ILDAS Program. The primary focus is to capture airframe current waveforms during attachment, but may also consider pre and post-attachment current, electric field, and radiated field phenomena. New sensor technologies are being developed for this system, including a fiber-optic Faraday polarization sensor that measures lightning current waveforms from DC to over several Megahertz, and has dynamic range covering hundreds-of-volts to tens-of-thousands-of-volts. A study of the electromagnetic emission spectrum of lightning (including radio wave, microwave, optical, X-Rays and Gamma-Rays), and a compilation of aircraft transfer-function data (including composite aircraft) are included, to aid in the development of other new lightning environment sensors, their placement on-board research aircraft, and triggering of the onboard instrumentation system. The instrumentation system will leverage recent advances in high-speed, high dynamic range, deep memory data acquisition equipment, and fiber-optic interconnect.

  10. 78 FR 76775 - Special Conditions: Airbus, Model A350-900 Series Airplane; Lightning Protection of Fuel Tank...

    Science.gov (United States)

    2013-12-19

    ... may be viewed at: http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgPolicy.nsf/0... has determined that the risk reduction provided by this additional performance will provide... fault tolerance is practical, and through a performance-based standard for the risk due to any...

  11. Lightning attachment process to common buildings

    Science.gov (United States)

    Saba, M. M. F.; Paiva, A. R.; Schumann, C.; Ferro, M. A. S.; Naccarato, K. P.; Silva, J. C. O.; Siqueira, F. V. C.; Custódio, D. M.

    2017-05-01

    The physical mechanism of lightning attachment to grounded structures is one of the most important issues in lightning physics research, and it is the basis for the design of the lightning protection systems. Most of what is known about the attachment process comes from leader propagation models that are mostly based on laboratory observations of long electrical discharges or from observations of lightning attachment to tall structures. In this paper we use high-speed videos to analyze the attachment process of downward lightning flashes to an ordinary residential building. For the first time, we present characteristics of the attachment process to common structures that are present in almost every city (in this case, two buildings under 60 m in São Paulo City, Brazil). Parameters like striking distance and connecting leaders speed, largely used in lightning attachment models and in lightning protection standards, are revealed in this work.Plain Language SummarySince the time of Benjamin Franklin, no one has ever recorded high-speed video images of a lightning connection to a common building. It is very difficult to do it. Cameras need to be very close to the structure chosen to be observed, and long observation time is required to register one lightning strike to that particular structure. Models and theories used to determine the zone of protection of a lightning rod have been developed, but they all suffer from the lack of field data. The submitted manuscript provides results from high-speed video observations of lightning attachment to low buildings that are commonly found in almost every populated area around the world. The proximity of the camera and the high frame rate allowed us to see interesting details that will improve the understanding of the attachment process and, consequently, the models and theories used by lightning protection standards. This paper also presents spectacular images and videos of lightning flashes connecting lightning rods that

  12. 中美外部雷电防护系统设计规范比较%Comparation of External Lightning Protection Systems Design Requirements between American Standards and Chinese Standards

    Institute of Scientific and Technical Information of China (English)

    傅剑锋; 杨凯; 徐定成

    2012-01-01

    The related technical requirements of external lightning protection in NFPA 780—2011,such as earthing electrode,downlead,air-termination system,materials of lightning protection system,risk assessment were introduced.NFPA 780—2011 was compared with the related Chinese lightning protection standard,regulations and standards.It could provide reference for more and more overseas project.%从风险评估、防雷系统的材料、接闪器、引下线、接地体等几个方面,介绍了NFPA780—2011外部防雷的相关技术要求,并与中国防雷设计规范的要求进行比较,为海外设计项目提供了设计参考。

  13. Analysis on Improvement of Lightning Protection of Nuclear Auxiliary Building Ventilation System of LING AO PhaseⅡ%岭澳二期核辅助厂房通风系统防雷改进分析

    Institute of Scientific and Technical Information of China (English)

    李明钢; 王耀刚; 李东; 关济实; 张立蕊

    2016-01-01

    Affected by climate, it is always raining in Guang Dong province and the Daya bay nuclear power plant always suffers from lightning. Therefore, it is very important to improve the lightning protection facilities. In order to solve the problems that lightning protection of nuclear auxiliary building ventilation system and other related component in Daya bay nuclear power plant reactor protection system, and improve the lightning protection level, a plan about improving the lightning protection facilities is proposed, and further analysis and demonstration are made as well, which are based on the actual situation. The plan of improving the lightning protection facilities is of great significance to the safe and stable operation of Daya bay nuclear power station.%受气候影响,广东大亚湾核电站多发雷雨,而雷击会严重威胁核电站的安全稳定运行。因此,提高防雷设施十分重要。针对大亚湾核电站反应堆保护系统相关的核辅助厂房通风系统的信号回路结构及容易受到雷电干扰部分的防雷保护问题,结合实际情况,对核辅助厂房通风系统的防雷设施进行改进及分析论证,提高防雷等级。该防雷设施改进方案对大亚湾核电站的安全稳定运行有着重要的意义。

  14. Lightning protection design for hydrological automatic measurement system of for middle and small rivers%中小河流水文自动测报系统防雷工程设计

    Institute of Scientific and Technical Information of China (English)

    黄余文

    2014-01-01

    In the consideration of environmental factors and lightning activity in the surrounding area of the central station of hydrological automatic measurement system for middle and small rivers in Wenshan Prefecture of Yunnan Province, the approach of artificial-triggered lightning for the system is systematically analyzed, and based on the principles of safety, economy, practi-cability and compliance with national standards, the feasible lightning protection schemes of external and internal structures are put forward. The external lightning protection is mainly realized by lightning rod (belt, network), down lead, grounding grid while the inner lightning protection is mainly realized by electromagnetic shielding, equipotential connection, lightning arrester ( SPD) . In addition, a common grounding body scheme shared with lightning protection body, work exchange ground body, static electricity ground, shielding ground, insulating ground is put forward, which not only safeguard the safety of lightning protection device, but also save the investment.%结合云南省文山州中小河流水文监测系统中心站周围的环境因素、雷电活动规律等,系统分析了水文自动测报系统的引雷途径,本着安全、经济、实用的原则,在遵循国家有关防雷标准的基础上,提出了切实可行的建筑物外部防雷和内部防雷设计方案。水文自动测报系统外部防雷设计侧重考虑避雷针(带、网)、引下线、接地网等方面,内部防雷设计则主要考虑电磁屏蔽、等电位连接、避雷器(SPD)3部分。并且,参考IEC国际电工委员会的有关防雷技术标准,提出了水文自动测报系统设备防雷地、工作交流地(N线)、静电地、屏蔽地、绝缘地等共用一个接地体的方案,既保证了防雷设备的安全性,又节约了工程投资。

  15. Influence of line isolation overlappings on formation of lightning overvoltages

    Directory of Open Access Journals (Sweden)

    Antropov I. M.

    2015-12-01

    Full Text Available The model of substation protection against lightning waves with considered multiple overlappings of line isolation has been presented. Influence of multiple overlapping of isolation on line support on formation of lightning overvoltages has been shown. Ambiguity of determination of lightning current dangerous parameters at the fixed length of its front has been revealed

  16. 太阳能光伏建筑雷电防护问题研究%Study of Lightning Protection for Solar Photovoltaic Building

    Institute of Scientific and Technical Information of China (English)

    郭福雁; 王宁

    2016-01-01

    Photovoltaic building is a combination of photovoltaic power generation technology and construction technology, which is not only a new trend of photovoltaic applications, but also a new development of green building. Because of the solar photovoltaic panels installed in the roof of buildings, the solar PV system is large and its installation height is high. Therefore, the probability of the lightning strike is apt to be higher than that of the common building. Moreover, the connect-ing wire between the components of the PV system is long, that is extremely vulnerable to the attack of lightning electromag-netic pulse, especially, the core parts of the system are vulnerable to be damaged. So, it is very important to design and install a set of safe, reliable and perfect lightning protection measures for photovoltaic building.%光伏建筑是光伏发电技术与建筑技术的结合,既是光伏应用的新趋势,也是绿色建筑的新发展。由于光伏发电系统的太阳能光伏板安装在建筑物的屋顶,占地面积大,安装高度高,因此,其遭受雷击的概率较一般建筑雷击概率高。而且,构成光伏系统的各部分组件间的连接线缆长,极易遭受雷击电磁脉冲的袭击,损坏系统中的核心部件。因此,设计、安装一套安全、可靠、完善的雷电防护措施对太阳能光伏建筑非常重要。

  17. Relativistic-microwave theory of ball lightning

    Science.gov (United States)

    Wu, H.-C.

    2016-06-01

    Ball lightning, a fireball sometimes observed during lightnings, has remained unexplained. Here we present a comprehensive theory for the phenomenon: At the tip of a lightning stroke reaching the ground, a relativistic electron bunch can be produced, which in turn excites intense microwave radiation. The latter ionizes the local air and the radiation pressure evacuates the resulting plasma, forming a spherical plasma bubble that stably traps the radiation. This mechanism is verified by particle simulations. The many known properties of ball lightning, such as the occurrence site, relation to the lightning channels, appearance in aircraft, its shape, size, sound, spark, spectrum, motion, as well as the resulting injuries and damages, are also explained. Our theory suggests that ball lighting can be created in the laboratory or triggered during thunderstorms. Our results should be useful for lightning protection and aviation safety, as well as stimulate research interest in the relativistic regime of microwave physics.

  18. Relativistic-microwave theory of ball lightning.

    Science.gov (United States)

    Wu, H-C

    2016-06-22

    Ball lightning, a fireball sometimes observed during lightnings, has remained unexplained. Here we present a comprehensive theory for the phenomenon: At the tip of a lightning stroke reaching the ground, a relativistic electron bunch can be produced, which in turn excites intense microwave radiation. The latter ionizes the local air and the radiation pressure evacuates the resulting plasma, forming a spherical plasma bubble that stably traps the radiation. This mechanism is verified by particle simulations. The many known properties of ball lightning, such as the occurrence site, relation to the lightning channels, appearance in aircraft, its shape, size, sound, spark, spectrum, motion, as well as the resulting injuries and damages, are also explained. Our theory suggests that ball lighting can be created in the laboratory or triggered during thunderstorms. Our results should be useful for lightning protection and aviation safety, as well as stimulate research interest in the relativistic regime of microwave physics.

  19. Aircraft Lightning Protection Handbook

    Science.gov (United States)

    1989-09-01

    ac generator tripoff (6 Instances of tripoff All of these effects will be considered indirect effects Autopilot I- in this discussion, even though...lines = 10’ kilolines (18.8) 0.Flux density: Flux density may be measured in teslas 00 (webers per square meter), gauss (or lines per square centimeter...e-’J (18.12) 1 tesla = 1 weber per meter2 = 1 tesla = 104 gauss the total volt-second product is 1 tesla = 1.550 x 10-5 lines/in 2 1 tesla

  20. Study on Secondary Equipment Lightning Protection for Traction Power Supply System%牵引供电系统二次设备防雷保护研究

    Institute of Scientific and Technical Information of China (English)

    温建民

    2012-01-01

    针对铁路牵引供电系统二次回路防雷问题进行研究和分析,提出在所用变压器、交直流电源回路、UPS电源回路、弱电回路等应采取分级防护方案以防过电压。%Study and analysis are made with respect of the problems of the secondary equipment lightning protection for the railway traction power supply system,the paper puts forward the graded protection plan for the auxiliary transformer circuit,AC or DC power circuit,UPS circuit and low voltage circuit so as to prevent the overvoltage.

  1. 官地矿6 kV送配电线路的防雷保护%Lightning protection for 6 kV power transmission and distribution lines of Guandi mine

    Institute of Scientific and Technical Information of China (English)

    刘彬

    2014-01-01

    6 kV送配电线路和雷击跳闸一直是困扰矿井安全供电的一个难题,雷击事故几乎占线路全部跳闸事故的一半以上。找到更好更有效的线路防雷保护措施是每个电力工作者关注的难题。通过对雷击线路的危害的分析,找出各种改善线路雷电性能的措施。%6 kV power transmission and distribution lines and lightning trip is always a problem in coal mine safety power supply lightning accident, accounting for almost half of the line all trip accident. In order to find a better line lightning protection meas-ures more effectively, is a problem to pay attention to each electricity workers. We analyzed the harm of lightning lines, find out all kinds of measures to improve the lightning performance of transmission lines.

  2. Lightning Performance on Overhead Distribution Lines : After Improvement Field Observation

    Directory of Open Access Journals (Sweden)

    Reynaldo Zoro

    2009-11-01

    Full Text Available Two feeders of 20 kV overhead distribution lines which are located in a high lightning density area are chosen to be observed as a field study due to their good lightning performance after improvement of lightning protection system. These two feeders used the new overhead ground wire and new line arrester equipped with lightning counter on the main lines. The significant reduced of lines outages are reported. Study was carried out to observe these improvements by comparing to the other two feeders line which are not improved and not equipped yet with the ground wire and line arrester. These two feeders located in the nearby area. Two cameras were installed to record the trajectory of the lightning strikes on the improved lines. Lightning peak currents are measured using magnetic tape measurement system installed on the grounding lead of lightning arrester. Lightning overvoltage calculations are carried out by using several scenarios based on observation results and historical lightning data derived from lightning detection network. Lightning overvoltages caused by indirect or direct strikes are analyzed to get the lightning performance of the lines. The best scenario was chosen and performance of the lines were improved significantly by installing overhead ground wire and improvement of lightning arrester installation.

  3. Protection against lightning surges provided by line arresters - Furnas' experience on 138 kV system

    Energy Technology Data Exchange (ETDEWEB)

    Camara, Alessandra S.B.; Esmeraldo, Paulo C.V.; Nigri, Armando [FURNAS Centrais Eletricas S.A., Rio de Janeiro, RJ (Brazil)

    1999-07-01

    Furnas is about to make use of the line surge arrester technology in its network, based on studies that have been developed regarding with line performance improvement. In association to such studies, Furnas has installed six line arresters units on a 138 kV line with an arrester manufacturer cooperation, in order to get some experience on installation and maintenance, besides lightning incidence monitoring and line arrester behavior analysis. This paper presents first results and conclusions related to this 138 kV experimental installation on Furnas system. (author)

  4. Breakdown tests of glass fibre reinforced polymers (GFRP) as part of improved lightning protection of wind turbine blades

    DEFF Research Database (Denmark)

    Madsen, Søren Find; Holbøll, Joachim; Henriksen, Mogens;

    2004-01-01

    This paper addresses a need for analysing the interaction between electrical discharges and GFRP. A test method for evaluating the breakdown and withstand voltages for materials used in wind turbine blades has been developed. The method is based on IEC 243-3, methods of test for electrical strength...... of solid insulating materials, and simulates the situation in a wind turbine blade, where a lightning discharge penetrates an insulating layer towards an inner earth conductor. Different GFRP materials supplied by Danish wind turbine blade manufacturers have been tested. In the subsequent experiments, both...

  5. Lightning Science: Five Ways Lightning Strikes People

    Science.gov (United States)

    ... Hurricanes Lightning Rip Currents Space Thunderstorms, Hail Tornadoes Tsunamis Ultraviolet (UV) Wildland Fires Wind Winter Weather INFORMATION ... affects a much larger area than the other causes of lightning casualties, the ground current causes the ...

  6. Over-voltage surge arrester for lightning protection; Einsatz von Ueberspannungsableitern beim Blitzschutz. Notwendige Strombelastbarkeit von Varistoren in induktiv gekoppelten Schleifen

    Energy Technology Data Exchange (ETDEWEB)

    Haeberlin, H. [Berner Fachhochschule, Hochschule fuer Technik und Architektur (HTA), Burgdorf, (Switzerland)

    2001-07-01

    The article discusses the necessary loading characteristics of varistors that are used in inductively coupled loops to provide protection against over-voltages produced by lightning strikes. An overview of various types of commercially available surge arresters is presented; their function and their use in photovoltaic installations is discussed in detail. The calculation of the inductively induced currents is discussed in depth for loops with and without varistors. Diagrams with graphs of current against time and mathematical solutions for the representation of the induced currents are presented in detail. The article is supplemented by examples of the calculation of varistor current and a simplified procedure is presented for the definition of the varistor currents necessary for a particular application.

  7. Towards FAA Certification of UAVs

    Science.gov (United States)

    Nelson, Stacy

    2003-01-01

    As of June 30, 2003, all Unmanned Aerial Vehicles (UAV), no matter how small, must adhere to the same FAA regulations as human-piloted aircraft. These regulations include certification for flying in controlled airspace and certification of flight software based on RTCA DO-178B. This paper provides an overview of the steps necessary to obtain certification, as well as a discussion about the challenges UAV's face when trying to meet these requirements. It is divided into two parts: 1) Certifications for Flying in Controlled Airspace; 2) Certification of Flight Software per RTCA DO-178B.

  8. Fine Selection of Lightning Protection Method of Distributed Photovoltaic Power Station%分布式光伏发电防雷措施的精细化选择

    Institute of Scientific and Technical Information of China (English)

    邓海利; 郭业才; 宋兆俊

    2015-01-01

    利用闪电监测系统确定光伏电站所在地的雷击大地密度,从而计算电站的年预计雷击次数,并划分防雷类别。提出用雷电统计资料来确定滚球半径,使直击雷保护范围计算更为精确。针对避雷针阴影对光伏电池板产生的热斑效应,提出使用太阳高度角及方位角来选择避雷针的安装位置,降低阴影对光伏电池板的影响。为降低热斑效应,建议大型光伏电站使用避雷线防护。提出利用雷电流幅值选取浪涌保护器(SPD )的冲击放电电流,降低SPD的钳制电压,优化SPD保护效果。提议控制机房结构内筋兼做屏蔽层,并根据雷电统计数据确定内筋的网格尺寸。最后提出根据光伏电池阵列的布局,结合当地土壤电阻率,分区域建设环形接地系统。%The lightning density around photovoltaic (PV ) power station is determined based on lightning location system . This density is used to calculate and predict the number of lightning at a year on average of the power station and divide lightning protection categories .Lightning statistical data is used to determine the ball radius ,making the lightning protection range calculation more accurate .The lightning rod shadow will produce hot spot effect on the PV cell panel ,so the average height and azimuth angle of sun is used to choose the installation location of lightning rod ,so as to reduce the effect of shadow for the PV cell panel .In order to reduce the hot spot effect it is suggested that the lightning line should be used in large-scale PV power station .It is proposed that the lightning current amplitude is applied to select Surge Protection Device (SPD ) ,reduce the max clamping voltage of SPD and to optimize the protection effect of SPD .The reinforced room is controlled to be shielding layer and according to the lightning statistical data ,the reinforced grid size is determined .At the end ,the regional constructed ring

  9. Seasonal and Local Characteristics of Lightning Outages of Power Distribution Lines in Hokuriku Area

    Science.gov (United States)

    Sugimoto, Hitoshi; Shimasaki, Katsuhiko

    The proportion of the lightning outages in all outages on Japanese 6.6kV distribution lines is high with approximately 20 percent, and then lightning protections are very important for supply reliability of 6.6kV lines. It is effective for the lightning performance to apply countermeasures in order of the area where a large number of the lightning outages occur. Winter lightning occurs in Hokuriku area, therefore it is also important to understand the seasonal characteristics of the lightning outages. In summer 70 percent of the lightning outages on distribution lines in Hokuriku area were due to sparkover, such as power wire breakings and failures of pole-mounted transformers. However, in winter almost half of lightning-damaged equipments were surge arrester failures. The number of the lightning outages per lightning strokes detected by the lightning location system (LLS) in winter was 4.4 times larger than that in summer. The authors have presumed the occurrence of lightning outages from lightning stroke density, 50% value of lightning current and installation rate of lightning protection equipments and overhead ground wire by multiple regression analysis. The presumed results suggest the local difference in the lightning outages.

  10. Development of lightning-resistant overhead ground wire

    Energy Technology Data Exchange (ETDEWEB)

    Yokoya, Munehisa; Katsuragi, Yukio (Chubu Electric Power Co., Inc., Nagoya (Japan)); Goda, Yutaka (Central Research Inst. of the Electric Power Industry, Yokosuka (Japan)); Nagata, Yutaka; Asano, Yuji (Fujikura Ltd., Tokyo (Japan))

    1994-07-01

    Overhead ground wires (GW) are vulnerable to strand breakage due to lightning strikes. With the wider application in recent years of Composite Fiber Optic Ground Wire (OPGW), it becomes more important to protect GW from such damage. In this paper, the authors present the results of various investigations made in developing lightning-resistant GW/OPGW. Investigations included field experiments using rocket-triggered lightning, studies on materials and designs to improve lightning characteristics and various evaluation tests, such as DC arc tests, of several prototypes. As a result, the authors have developed excellent lightning-resistant GW/OPGW applicable for conventional transmission lines.

  11. 配电网雷电防护措施总结分析及其应用%The Summary of Lightning Protection Measures and Its Applications for the Distribution Network

    Institute of Scientific and Technical Information of China (English)

    李德峰; 陈述

    2014-01-01

    配电网很容易遭受雷害引起停电或跳闸事故,影响电网的安全稳定运行。总结了现行的配网防雷的主要措施,对每项措施的优缺点进行分析研究。把总结的防雷措施应用在实际的配电网中,通过2个成功提高配网雷电水平的应用案例,为配电网中心供电所防雷改造及10 kV配网线路防雷改造提供了借鉴。%Distribution network is vulnerable to lightning damage and caused power outages or tripping accidents,which affect the safe and stable operation of the power grid. This paper summarizes the main measures of the Lightning Protection Measures for distribution network. advantages and disadvantages of each of these measures were analyzed. The summary of of the lightning protection measures was applied in the actual distribu-tion network,This paper provides a reference for the Distribu-tion Network to Improve the ability to respond to lightning.

  12. Lightning Technology.

    Science.gov (United States)

    1980-04-01

    33-38, 1975. 6. Schonland, B.F.J., The Lightning Discharge, Handbuch der Physik , 22, 576-628, Springer-Verlag, OHG, Berlin, 1956. 25 (K,z) R GROUND o... Dictionary of Electrical and Electronic Terms, IEEE Std 100-1977, New York, John Wiley & Sons, Inc., 1977. 313 cc C 0J 0J o -4 0$4j 4j)4J 0 1.4 >- ~ o 0 0 .,.C...Electric Power Research Institute) EL-1140, Project 1141 Final Report, Sept. 1979. 8. IEEE Standard Dictionary of Electrical and Electronics Terms, Wiley

  13. Discussion on the Lightning Protection Construction Technology and Announcements in Building Electrical Installation%关于建筑电气安装中防雷接地施工技术与注意事项的探讨

    Institute of Scientific and Technical Information of China (English)

    朱春健

    2013-01-01

    现代建筑电气安装中防雷接地施工是比较关键的环节,其施工质量的好坏直接影响着电气安装的安全性。因防雷接地施工是一项系统的工程,在施工过程中要严格把控各个技术环节,做好相关的管理工作与注意事项。%Lightning protection and grounding construction in modern building electrical instal ation is the key link, its cons-truction quality directly affects the safety of electrical instal a-tion. Because of the lightning protection and grounding constr-uction is a systematic project, it needs to strictly control the various links in the construction process, do a good job in the relevant administrations and announcements.

  14. Design and Implementation of the Lightning Protection in Jiaxiang GNSS Base Station of CMONOC%陆态网络嘉祥基准站防雷避雷的设计实施

    Institute of Scientific and Technical Information of China (English)

    刘作华; 冯志军

    2014-01-01

    According to the actual situation of Jiaxiang GNSS base station,This article has been given a detailed de-scription of lightning protection measures for base station. Especially lightning protection in mountain area ,what jiaxiang GNSS base station to do is relatively successful,which can be used for reference to other base stations and some similar geological conditions stations ,microwave radar stations,television stations and other stations.%本文对陆态网络嘉祥基准站的所采取的避雷措施进行了详细的说明。对有类似地质情况的基站、微波站、电视差转台等做好防雷避雷能够起到一定的借鉴作用。

  15. International Aerospace and Ground Conference on Lightning and Static Electricity. 1984 technical papers. Supplement

    Science.gov (United States)

    1984-01-01

    The indirect effects of lightning on digital systems, ground system protection, and the corrosion properties of conductive materials are addressed. The responses of a UH-60A helicopter and tactical shelters to lightning and nuclear electromagnetic pulses are discussed.

  16. Statistical analysis of lightning electric field measured under Malaysian condition

    Science.gov (United States)

    Salimi, Behnam; Mehranzamir, Kamyar; Abdul-Malek, Zulkurnain

    2014-02-01

    Lightning is an electrical discharge during thunderstorms that can be either within clouds (Inter-Cloud), or between clouds and ground (Cloud-Ground). The Lightning characteristics and their statistical information are the foundation for the design of lightning protection system as well as for the calculation of lightning radiated fields. Nowadays, there are various techniques to detect lightning signals and to determine various parameters produced by a lightning flash. Each technique provides its own claimed performances. In this paper, the characteristics of captured broadband electric fields generated by cloud-to-ground lightning discharges in South of Malaysia are analyzed. A total of 130 cloud-to-ground lightning flashes from 3 separate thunderstorm events (each event lasts for about 4-5 hours) were examined. Statistical analyses of the following signal parameters were presented: preliminary breakdown pulse train time duration, time interval between preliminary breakdowns and return stroke, multiplicity of stroke, and percentages of single stroke only. The BIL model is also introduced to characterize the lightning signature patterns. Observations on the statistical analyses show that about 79% of lightning signals fit well with the BIL model. The maximum and minimum of preliminary breakdown time duration of the observed lightning signals are 84 ms and 560 us, respectively. The findings of the statistical results show that 7.6% of the flashes were single stroke flashes, and the maximum number of strokes recorded was 14 multiple strokes per flash. A preliminary breakdown signature in more than 95% of the flashes can be identified.

  17. Characteristics of Lightning Discharges and Electric Structure of Thunderstorm

    Institute of Scientific and Technical Information of China (English)

    Qie Xiushu; Zhang Yijun; Zhang Qilin

    2006-01-01

    Progresses in the research on physical processes of lightning discharge and electric structure of thunderstorm in the last decade in China have been reviewed. By using the self-developed lightning detecting and locating techniques with high temporal and spatial resolution, the characteristics and parameters of lightning discharge in some representative areas in China have been obtained. Observations on lightning activity were conducted for the first time in the Qinghai-Tibetan Plateau in 2002-2005, and the special characteristics of the thunderstorm and lightning activity in the plateau were revealed. The lightning spectra in the band of visible light were recorded, and the spectral lines were identified in detail with introduction of modern theories of atomic structure. The techniques on artificially altitude triggered lightning and related measurements under a harsh electromagnetic environment have been well developed. Evidences of bi-directional leader propagation were observed by means of optics and VHF radiation during the triggered lightning discharges. Some lightning protection devices have been tested using the artificial lightning triggering techniques. In addition, the correlation between lightning activities and weather and climate was preliminarily studied.

  18. Theory of ball lightning

    CERN Document Server

    Wu, H -C

    2014-01-01

    We present a comprehensive explanation on ball lightning, a luminous sphere occasionally witnessed after ordinary lightning. In the last decade, it has been well established that natural lightning routinely generates relativistic electrons, which account for observed x rays. So we assume that, in a ball lightning event, a well-defined relativistic electron bunch is produced by the stepped leader of lightning. When this electron bunch strikes various media, a powerful microwave pulse is emitted by the coherent transition radiation mechanism. This intense microwave ionizes air, evacuates plasmas by its radiation pressure to form a globular plasma cavity, and then gets trapped inside the cavity. This theory successfully explains all characteristics of ball lightning, especially the appearance of ball lightning in fully-screened aircraft. Moreover, the proposed radiation mechanism fully explains the strongest radio signals from lightning and nanosecond spikes in the signals are direct evidences on the generation ...

  19. The lightning flash

    CERN Document Server

    Cooray, Vernon

    2014-01-01

    With contributions from today's leading lightning engineers and researchers, this updated 2nd edition of Vernon Cooray's classic text, The Lightning Flash provides the reader with an essential introduction to lightning and its impact on electrical and electronic equipment. Providing the reader with a thorough background into almost every aspect of lightning and its impact on electrical and electronic equipment, this new edition is updated throughout and features eight new chapters that bring the science up to date.

  20. Lightning safety of animals.

    Science.gov (United States)

    Gomes, Chandima

    2012-11-01

    This paper addresses a concurrent multidisciplinary problem: animal safety against lightning hazards. In regions where lightning is prevalent, either seasonally or throughout the year, a considerable number of wild, captive and tame animals are injured due to lightning generated effects. The paper discusses all possible injury mechanisms, focusing mainly on animals with commercial value. A large number of cases from several countries have been analyzed. Economically and practically viable engineering solutions are proposed to address the issues related to the lightning threats discussed.

  1. The Quality Control Algorithms Used in the Process of Creating the NASA Kennedy Space Center Lightning Protection System Towers Meteorological Database

    Science.gov (United States)

    Orcutt, John M.; Brenton, James C.

    2016-01-01

    The methodology and the results of the quality control (QC) process of the meteorological data from the Lightning Protection System (LPS) towers located at Kennedy Space Center (KSC) launch complex 39B (LC-39B) are documented in this paper. Meteorological data are used to design a launch vehicle, determine operational constraints, and to apply defined constraints on day-of-launch (DOL). In order to properly accomplish these tasks, a representative climatological database of meteorological records is needed because the database needs to represent the climate the vehicle will encounter. Numerous meteorological measurement towers exist at KSC; however, the engineering tasks need measurements at specific heights, some of which can only be provided by a few towers. Other than the LPS towers, Tower 313 is the only tower that provides observations up to 150 m. This tower is located approximately 3.5 km from LC-39B. In addition, data need to be QC'ed to remove erroneous reports that could pollute the results of an engineering analysis, mislead the development of operational constraints, or provide a false image of the atmosphere at the tower's location.

  2. Fire and lightning: what are the risks and how to be protected?; Incendie et foudre: Quel sont les risques et comment se proteger?

    Energy Technology Data Exchange (ETDEWEB)

    Rigal, F.

    2011-04-15

    This article reviews the risks of fire and lightning on photovoltaic panels installed on roofs. It appears that the risk of lighting must be taken into account since the direct impact of lightning on photovoltaic panels can be disastrous. The installation of lightning rods or lightning protector is recommended. Concerning fire risks, technical failures or the presence of electric arcs can put fire on solar panels but their occurrence is very low (only about 20 cases reported in Europe for the last 10 years). Tests have shown that standard photovoltaic panels play a low part in the progressing of a fire. There is an electrocution hazard for firemen intervening on a roof bearing solar panels. A device cutting the continuous current generating by the panels is being studied. (A.C.)

  3. Analysis on Lightning Protection Performance of Metal Oxide Surge Arresters for Transmission Lines%复合绝缘外套线路型ZnO避雷器防雷运行分析

    Institute of Scientific and Technical Information of China (English)

    李谦; 钟定珠; 彭向阳; 樊灵孟; 罗真海; 林火华

    2001-01-01

    According to analysis of the lightning protection practice of Metal Oxide Surge Arresters on the Guangdong 110 kV and 220 kV Transmission Lines in recent years, the positive effectiveness of Metal Oxide Surge Arresters on lowering the lightning stroke tripp efficiency has been preliminarily affirmed. The existing issues in the site-selection, installation and maintenance are discussed, the beneficial suggestions for popularizationis also presented.%总结了复合绝缘外套线路型ZnO避雷器近年在广东省110、220 kV输电线路的运行经验;肯定了线路避雷器降低线路雷击跳闸率的积极效果;讨论了在解决选点、安装和运行维护等方面存在的问题并提出了建议。

  4. 关中环线站场仪表系统防雷工程设计浅析%Analysis of Instrument System Lightning Surge Protection on Guanzhong Pipeline Station

    Institute of Scientific and Technical Information of China (English)

    李娇媚; 王贵波

    2014-01-01

    Natural gas station instrument system lightning current intrusion caused equipment damage and affected production in high frequency region. Taken Guanzhong natural gas storage peak shaving pipeline project for instance, in the sight of loop and system, integrated consideration of lightning surge protection, improved the security and the stability of system.%针对天然气站场仪表系统在高雷区受雷电流入侵,导致设备损坏,从而影响生产的问题。以关中环线天然气储气调峰管道工程为例,从回路和系统的角度,综合考虑防雷措施,使系统防雷的可靠性得到提升。

  5. Application of Soil Resistivity Test in Airport Lightning Protection Design%土壤电阻率检测分析在机场防雷设计中的应用

    Institute of Scientific and Technical Information of China (English)

    李衣长; 王婷婷; 龚成龙; 龚伟; 巫圣灿

    2015-01-01

    对某民用机场开展雷电灾害风险评估,采用温纳四极法测试土壤电阻率,对检测数据进行水平分布和垂直分布分析,利用土壤结构反演方法,得到一个等效的均匀土壤电阻率,为机场防雷接地装置设计提供了科学化、精细化的依据。%Lightning disaster risk assessment is conducted for a civil airport; Wenner quadrupole method is adopted to test the soil resistivity. An equivalent and uniform soil resistivity, which is obtained through horizontal and vertical distribution analysis on tested data and by soil structure inversion method, provides a scientific and precise basis for grounding device design for airport lightning protection.

  6. MSFC shuttle lightning research

    Science.gov (United States)

    Vaughan, Otha H., Jr.

    1993-01-01

    The shuttle mesoscale lightning experiment (MLE), flown on earlier shuttle flights, and most recently flown on the following space transportation systems (STS's), STS-31, -32, -35, -37, -38, -40, -41, and -48, has continued to focus on obtaining additional quantitative measurements of lightning characteristics and to create a data base for use in demonstrating observation simulations for future spaceborne lightning mapping systems. These flights are also providing design criteria data for the design of a proposed shuttle MLE-type lightning research instrument called mesoscale lightning observational sensors (MELOS), which are currently under development here at MSFC.

  7. Experiments of Wind Turbine Blades with Rocket Triggered Lightning

    Science.gov (United States)

    Minowa, Masayuki; Sumi, Shinichi; Minami, Masayasu; Horii, Kenji

    This paper describes the results of the experiments of wind turbine blades with rocket triggered lightning. A number of wind power stations have been projected and planted. Lightning damage to wind turbines has been an increasing problem recently. So development on protection of wind power plants from lightning is necessary to be fully run for the future. In the experiments, the 1.8m long blade was struck by the lightning discharge triggered by rocket. For the blade kept dry inside, the very strong discharge of positive peak current 28kV, total charge 520 Coulombs, was triggered, but the breakdown did not occur through the blade into inside. Another blade polluted by salty wet inside was struck by the lightning discharge of negative peak current of 4kA with 0.5 Coulombs. The lightning was small, nevertheless, the blade was broken at the upper edge and the blade was disconnected by crack. For the protection of blade, the blade surface was covered with stainless steel plate. The blade itself was safe when the big positive lightning discharged, while most part of stainless steel cover was burned out. Supplement breakdown tests of wind turbine blade were carried out with lightning impulse voltage in laboratory. As a result, it became clear that the blade kept dry inside was an effective lightning protection of wind turbine blades.

  8. Self-response multi-functional composite material base on carbon nanotube paper using deicing, flame retardancy, thermal insulation, and lightning-strike protection

    Science.gov (United States)

    Chu, Hetao; Zhang, Zhichun; Liu, Yanju; Leng, Jinsong

    2015-04-01

    Carbon nanotube paper (CNP) based multi-functional composite material is an attractive candidate for deicing, flame retardancy, thermal insulation and lighting strike protection due to the excellent conductivity, light weight and thin dimensions. In this article, multi-functional carbon nanotube paper was fabricated successfully by using commercial carbon nanotube. As a deicing composite material, carbon nanotube was used directly without pretreatment in fabricating carbon nanotube paper. The conductivities of the carbon nanotube paper and deicing composite were 77.8S/cm and 64.9S/ respectively. Electrical heating and deicing performance were test by infrared camera with deicing time less than 220s and 450s to melt a certain amount of ice under different ambient condition. CNT was grafted by zirconium (IV) butoxide solution and dimethyl dichlorosilicane to form co-oligomers on the tube surface while oligomers decompose under a certain temperature to develop an inorganic layer of silicon zirconium oxide. The oxidizing temperature of carbon nanotube increases more than 20°C and the weight loss rate decreases 20% than the untreated carbon nanotube. Lightning protection material required high electro conductivity, due to the utmost high current in a short time. Therefore, silver nanoparticles were deposited on the surface of carbon nanotube with the diameter around 100nm. The conductivity increased sharply from 84s/cm to1756s/cm with the mount of 5.9wt% Ag of the modified carbon nanotube paper because the silver nanoparticles deposited on the surface. In addition, the silver modified also can be used as thermal insulation material decreasing the infrared radiation.

  9. 30 CFR 77.508-1 - Lightning arresters; wires entering buildings.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Lightning arresters; wires entering buildings... OF UNDERGROUND COAL MINES Electrical Equipment-General § 77.508-1 Lightning arresters; wires entering buildings. Lightning arresters protecting exposed telephone wires entering buildings shall be provided...

  10. Discussion on Matters Involving Protection against Lightning Back Flashover for Trees and Nearby Civilian Houses%树木及邻近民居防雷电反击相关问题探讨

    Institute of Scientific and Technical Information of China (English)

    汝洪博; 马金福; 王海芳

    2016-01-01

    Based on the research on the mutual effect of protection against lightning measures adopted for trees and nearby civilian houses, the article analyzes the requirements on protection against lightning back flashover for trees and nearby civilian houses where air-termination system are provided, and comes to the following conclusions: requirements on protection against lightning back flashover can be understood as the constraints on the impulse earthing resistance ( Ri) and safe distance ( Sa1) of tree’s earthing electrode; the design value of Ri and Sa1 shall be set according to specification and such constraints; safe distance among underground earthing electrodes and metal pipelines shall be considered for trees and civilian houses adopting separate protection against lightning device; in case Ri and Sa1 in actual works cannot meet protection requirements, other protection measures shall be taken.%以树木及其邻近民居防雷措施的相互影响为研究对象,详细分析安装接闪装置的树木与邻近民居防雷电反击相关要求,得出:防雷电反击相关要求可以看作是树木接地体的冲击接地电阻Ri与安全距离Sa1二者的约束条件, Ri和Sa1的设计要求值除了依照规范设计外,还应结合该约束条件综合考虑;各自独立设计防雷装置的树木与民居建筑尚应考虑地下接地体间及与金属管道的安全距离;当实际工程中Ri和Sa1无法满足防反击要求时,应采取其他防护措施。

  11. Research on the Lightning Indirect Effects Harm and Protection for Aircraft%飞行器雷电间接效应危害及其防护研究

    Institute of Scientific and Technical Information of China (English)

    滕向如; 刘光斌; 余志勇; 庄信武

    2014-01-01

    雷电对飞行器的损伤作用分为直接效应和间接效应,间接效应可能导致内部电子电气设备及系统功能紊乱或丧失。本文在分析雷电特性的基础上,应用理论分析和计算的方法,探究了飞行器雷电间接效应的作用机理,并结合GJB 1389A[1]、GJB 2639-1996[2]等标准对间接效应试验和雷电防护方案进行了设计。%The possible damage effects of lightning to aircraft can be divided into direct effects and indirect effects. The indirect effects may lead the function of the inner electrical/electronic equipments and systems to disorder or lose. Work mechanism of the lightning indirect effects is mainly analyzed by the method of theoretical analysis and calculating, which is on the basis of the characters of lightning, the indirect effects test and protection project are designed by referring to the standards GJB 1389A, GJB 2639-1996, etc.

  12. Simulation of lightning attachment to open ground, tall towers and aircraft

    Energy Technology Data Exchange (ETDEWEB)

    Ratnamahilan, P.; Hoole, P. (Univ. of Technology, Lae (Papua New Guinea). Dept. of Electrical and Telecommunications Engineering); Ratnajeevan, S.; Hoole, H. (Harvey Mudd College, Claremont, CA (United States). Dept. of Engineering)

    1993-04-01

    The characteristics of lightning waveforms are important in taking protective measures against it. However, many of these characteristics cannot be measured. This paper employs a mathematical model of lightning currents to write a software package to simulate all manner of lightning flashes. The capabilities available to us through this are demonstrated by extracting the behavior of lightning waveforms following attachment to open ground, tall towers and aircraft.

  13. Installation rules for low-voltage lightning arresters; Regles d'installation des parafoudres basse tension

    Energy Technology Data Exchange (ETDEWEB)

    Mignardot, D. [Schneider Electric, 38 - Grenoble (France)

    1998-06-01

    Following assessment of lightning risk and selection of a suitable lightning arrester for the installation, knowledge of good practice in arrester installation is crucial in obtaining genuinely effective protection. Major concepts here include earthing diagrams, building equipotentiality, lightning arrester cascade arrangements, and device disconnection and coordination plans. Understanding of these concepts is important in ensuring effective protection against overvoltages of atmospheric origin. (authors)

  14. Lightning Injury: A Review

    Science.gov (United States)

    2008-01-01

    bilateral perilymphatic fistulas from a lightning strike have been reported [65,68]. Other neuro-otologic findings have included transient vertigo...Keraunopathology. An analysis of 45 fatalities. Am J Forensic Med Pathol 1996;17(2):89–98. [7] Blumenthal R. Lightning fatalities on the South African...Trauma 1989;29(5):665–71. [65] Sun GH, Simons JP, Mandell DL. Bilateral perilymphatic fistulas from a lightning strike: a case report. Laryngoscope

  15. Nowcasting of Lightning-Related Accidents in Africa

    Science.gov (United States)

    Ihrlich, Laura; Price, Colin

    2016-04-01

    Tropical Africa is the world capital of thunderstorm activity with the highest density of strikes per square kilometer per year. As a result it is also the continent with perhaps the highest casualties and injuries from direct lightning strikes. This region of the globe also has little lightning protection of rural homes and schools, while many casualties occur during outdoor activities (e.g. farming, fishing, sports, etc.) In this study we investigated two lightning-caused accidents that got wide press coverage: A lightning strike to a Cheetah Center in Namibia which caused a huge fire and great destruction (16 October 2013), and a plane crash in Mali where 116 people died (24 July 2014). Using data from the World Wide Lightning Location Network (WWLLN) we show that the lightning data alone can provide important early warning information that can be used to reduce risks and damages and loss of life from lightning strikes. We have developed a now-casting scheme that allows for early warnings across Africa with a relatively low false alarm rate. To verify the accuracy of our now-cast, we have performed some statistical analysis showing relatively high skill at providing early warnings (lead time of a few hours) based on lightning alone. Furthermore, our analysis can be used in forensic meteorology for determining if such accidents are caused by lightning strikes.

  16. Effect of Multiple Lightning Strikes on .the Performance of ZnOLightning Arrester Block%Effect of Multiple Lightning Strikes on .the Performance of ZnOLightning Arrester Block

    Institute of Scientific and Technical Information of China (English)

    Haryono T; Sirait K T; Tumiran; Hamzah Berahim

    2011-01-01

    A lightning arrester is used for electrical equipment protection against damage due to lightning strikes. One example of protected electrical equipment is electrical power transformer. If there is no lightning arrester installed to the transformer, when a lightning strike happens, it may receive a very high lightning overvoltage, which is certainly resulted in the transformer damage at its insulation. Usually, a lightning arrester specification data attached to a light- ning arrester contains the rating data of the lightning arrester current and voltage. In the use of lightning arrester, the possibility of receiving multiple lightning strikes is not taken into account sometimes. In fact, in some places, the number of multiple strikes in short duration is quiet high in number. This condition makes the lightning arrester being stroked by multiple lightning strikes. Therefore, it may change the lightning arrester's properties, and then the arrester may not be able to provide good electrical equipment protection against lightning strike anymore. This condition will result in great loss to electrical companies and electrical consumers. Therefore, this research studied the effect of applying multiple lightning strikes to ZnO lightning arrester block. Every time a group of lightning impulse current is applied to the ZnO lightning arrester block, it is followed by the measuring of its 50 Hz voltage and current characteristic. The changing in the ZnO lightning arrester block 50 Hz characteristic then can be analyzed. It was found that by applying more numbers of lightning strikes which made the arrester becoming worse, even though, actually, the lightning impulse peak current was still under the rating of the lightning arrester current. In this ease for a 5 kA, 24 kV lightning arrester, even though the lightning impulse peak current flowing through the ZnO lightning arrester block was still 2500 A, the lightning arrester ZnO block had already been damaged. Having been

  17. Lightning injury: a review.

    Science.gov (United States)

    Ritenour, Amber E; Morton, Melinda J; McManus, John G; Barillo, David J; Cancio, Leopoldo C

    2008-08-01

    Lightning is an uncommon but potentially devastating cause of injury in patients presenting to burn centers. These injuries feature unusual symptoms, high mortality, and significant long-term morbidity. This paper will review the epidemiology, physics, clinical presentation, management principles, and prevention of lightning injuries.

  18. The physics of lightning

    Energy Technology Data Exchange (ETDEWEB)

    Dwyer, Joseph R., E-mail: jdwyer@fit.edu [Department of Physics and Space Sciences, Florida Institute of Technology, Melbourne, FL 32901 (United States); Uman, Martin A. [Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL 32611 (United States)

    2014-01-30

    Despite being one of the most familiar and widely recognized natural phenomena, lightning remains relatively poorly understood. Even the most basic questions of how lightning is initiated inside thunderclouds and how it then propagates for many tens of kilometers have only begun to be addressed. In the past, progress was hampered by the unpredictable and transient nature of lightning and the difficulties in making direct measurements inside thunderstorms, but advances in instrumentation, remote sensing methods, and rocket-triggered lightning experiments are now providing new insights into the physics of lightning. Furthermore, the recent discoveries of intense bursts of X-rays and gamma-rays associated with thunderstorms and lightning illustrate that new and interesting physics is still being discovered in our atmosphere. The study of lightning and related phenomena involves the synthesis of many branches of physics, from atmospheric physics to plasma physics to quantum electrodynamics, and provides a plethora of challenging unsolved problems. In this review, we provide an introduction to the physics of lightning with the goal of providing interested researchers a useful resource for starting work in this fascinating field.

  19. Fractal model of lightning channel for simulating lightning strikes to transmission lines

    Institute of Scientific and Technical Information of China (English)

    HE JinLiang; ZHANG XueWei; DONG Lin; ZENG Rong; LIU ZeHong

    2009-01-01

    How to accurately evaluate the direct-strike lightning protection is one of the key issues in the design of transmission lines.In this paper, three important issues in applying the fractal simulation to the lightning protection of transmission lines were discussed, including the criteria and implementation of upward leader inception, the connection with the magnitude of lightning current, and the calculation and control of fractal dimensions.Then we conducted the simulation iterately, leading to statistical results, which indicate that even if the transmission line satisfies the perfect shielding condition, shielding failure fault remains possible.Furthermore, we calculated the shielding failure fault rates of an EHV line with different ground obliquities and distribution of strike points over the interval between two neighboring towers along a UHV-DC line to find out the weak point of transmission-line lightning protection.This work provides a promising approach for improving the lightning protection property of transmission lines by optimizing the configuration of shielding wires and phase or pole conductors.

  20. Fractal model of lightning channel for simulating lightning strikes to transmission lines

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    How to accurately evaluate the direct-strike lightning protection is one of the key issues in the design of transmission lines. In this paper, three important issues in applying the fractal simulation to the lightning protection of transmission lines were discussed, including the criteria and implementation of upward leader inception, the connection with the magnitude of lightning current, and the calculation and control of fractal dimensions. Then we conducted the simulation iterately, leading to statistical results, which indicate that even if the transmission line satisfies the perfect shielding condition, shielding failure fault remains possible. Furthermore, we calculated the shielding failure fault rates of an EHV line with different ground obliquities and distribution of strike points over the interval between two neighboring towers along a UHV-DC line to find out the weak point of transmission-line lightning protection. This work provides a promising approach for improving the lightning protection property of transmission lines by optimizing the configuration of shielding wires and phase or pole conductors.

  1. 基于防雷接地需求的土壤结构模型研究%Model Research of Soil Structure Based on Demand of Lightning Protection Grounding

    Institute of Scientific and Technical Information of China (English)

    李虹

    2012-01-01

    确定大地模型和土壤参数是大型地网防雷接地计算的首要工作。土壤电阻率是影响接地阻抗的主要因素之一,它对防雷接地的效果起着重要作用。根据等距四极法测得的土壤视在电阻率,使用遗传算法建立的反演多层水平分层土壤电阻率模型,可反演出土壤的分层结构。三个实例计算结果表明,本模型计算结果和国际著名软件包CDEGS的计算结果非常接近。%Confirming the ground model and soil parameter is the most important work protection grounding computation for large grounding system. The soil resistivity is one of affe of lightning cting ground impedance primary factors; it plays an important role in the lightning protection grounding effect. Based on the equal-space four-pole method measured soil apparent resistivity, the use of genetic algorithm to build the inversion of muhilayer horizontal layered soil resistivity model can be inverted soil layer structure. Three cases show the model calculation results and the famous international software package CDEGS calculation results are close.

  2. Lightning Damage to Wind Turbine Blades From Wind Farms in the U.S

    DEFF Research Database (Denmark)

    Candela Garolera, Anna; Madsen, Søren Find; Nissim, Maya;

    2016-01-01

    This paper presents statistical data about lightning damage on wind turbine blades reported at different wind farms in the U.S. The analysis is based on 304 cases of damage due to direct lightning attachment on the blade surface. This study includes a large variety of blades with different lengths......, laminate structure, and lightning protection systems. The statistics consist of the distribution of lightning damage along the blade and classify the damage by severity. In addition, the frequency of lightning damage to more than one blade of a wind turbine after a thunderstorm is assessed. The results...

  3. Indirect Lightning Safety Assessment Methodology

    Energy Technology Data Exchange (ETDEWEB)

    Ong, M M; Perkins, M P; Brown, C G; Crull, E W; Streit, R D

    2009-04-24

    facility, when the facility is struck by lightning. In the following examples we will use Dr. Merewether's calculations from a poor quality Faraday cage as the input for the RF coupling analysis. coupling of radio frequency (RF) energy to explosive components is an indirect effect of currents [1]. If HE is adequately separated from the walls of the facility that is struck by disassembled have been turned into Faraday-cage structures to protect against lightning is initiation of the HE. last couple of decades, DOE facilities where HE is manufactured, assembled, stored or lightning. The most sensitive component is typically a detonator, and the safety concern lightning, electrons discharged from the clouds should not reach the HE components. radio receiver, the metal cable of a detonator can extract energy from the EM fields. This to the earth will create electromagnetic (EM) fields in the facility. Like an antenna in a

  4. Infrasound Observations from Lightning

    Science.gov (United States)

    Arechiga, R. O.; Johnson, J. B.; Edens, H. E.; Thomas, R. J.; Jones, K. R.

    2008-12-01

    To provide additional insight into the nature of lightning, we have investigated its infrasound manifestations. An array of three stations in a triangular configuration, with three sensors each, was deployed during the Summer of 2008 (July 24 to July 28) in the Magdalena mountains of New Mexico, to monitor infrasound (below 20 Hz) sources due to lightning. Hyperbolic formulations of time of arrival (TOA) measurements and interferometric techniques were used to locate lightning sources occurring over and outside the network. A comparative analysis of simultaneous Lightning Mapping Array (LMA) data and infrasound measurements operating in the same area was made. The LMA locates the sources of impulsive RF radiation produced by lightning flashes in three spatial dimensions and time, operating in the 60 - 66 MHz television band. The comparison showed strong evidence that lightning does produce infrasound. This work is a continuation of the study of the frequency spectrum of thunder conducted by Holmes et al., who reported measurements of infrasound frequencies. The integration of infrasound measurements with RF source localization by the LMA shows great potential for improved understanding of lightning processes.

  5. Note on lightning temperature

    Energy Technology Data Exchange (ETDEWEB)

    Alanakyan, Yu. R., E-mail: yralanak@mail.ru [Department of General and Applied Physics, Moscow Institute of Physics and Technology (State University), Dolgoprudny, 141700 Moscow Region (Russian Federation)

    2015-10-15

    In this paper, some features of the dynamics of a lightning channel that emerges after the leader-streamer process, are theoretically studied. It is shown that the dynamic pinch effect in the channel becomes possible if a discharge current before the main (quasi-steady) stage of a lightning discharge increases rapidly. The ensuing magnetic compression of the channel increases plasma temperature to several million degrees leading to a soft x-ray flash within the highly ionized plasma. The relation between the plasma temperature and the channel radius during the main stage of a lightning discharge is derived.

  6. Lightning hazards to aircraft

    Science.gov (United States)

    Corn, P. B.

    1978-01-01

    Lightning hazards and, more generally, aircraft static electricity are discussed by a representative for the Air Force Flight Dynamics Laboratory. An overview of these atmospheric electricity hazards to aircraft and their systems is presented with emphasis on electrical and electronic subsystems. The discussion includes reviewing some of the characteristics of lightning and static electrification, trends in weather and lightning-related mishaps, some specific threat mechanisms and susceptible aircraft subsystems and some of the present technology gaps. A roadmap (flow chart) is presented to show the direction needed to address these problems.

  7. TVA's experience with the SUNYA lightning detection network

    Energy Technology Data Exchange (ETDEWEB)

    Whitehead, J.; Driggans, R. (Tennessee Valley Authority, Chattanooga, TN (USA))

    1990-10-01

    Since 1987 the Tennessee Valley Authority (TVA) has had access to real-time data on cloud-to-ground lightning strikes in its service area through the Lightning Detection Network (LDN) operated by the State University of New York at Albany (SUNYA). Lightning data are displayed in real-time on personal computer workstations connected to SUNYA via satellite link and are recorded for later analysis. TVA is using these data to analyze transmission line outages (real-time and historical), provide warning of approaching lightning to line crews, develop ground flash density maps to replace isokeraunic maps previously used in designing transmission lines for lightning protection, and to learn more about lightning and its effect on TVA's transmission system. Lightning flashes that cause particular line outages have been identified and their current and multiplicity characteristics studied. This information may be used to allow more cost-effective transmission line design in the future.

  8. The effects of lightning on digital flight control systems

    Science.gov (United States)

    Plumer, J. A.; Malloy, W. A.; Craft, J. B.

    1976-01-01

    Present practices in lightning protection of aircraft deal primarily with the direct effects of lightning, such as structural damage and ignition of fuel vapors. There is increasing evidence of troublesome electromagnetic effects, however, in aircraft employing solid-state microelectronics in critical navigation, instrumentation and control functions. The potential impact of these indirect effects on critical systems such as digital fly by wire (DFBW) flight controls was studied. The results indicate a need for positive steps to be taken during the design of future fly by wire systems to minimize the possibility of hazardous effects from lightning.

  9. Lightning Threat Analysis for the Space Shuttle Launch Pad and the Payload Changeout Room Using Finite Difference Methods

    Science.gov (United States)

    Collier, Richard S.

    1997-01-01

    This report describes finite difference computer calculations for the Space Shuttle Launch Pad which predict lightning induced electric currents and electric and magnetic fields caused by a lightning strike to the Lightning Protection System caternary wire. Description of possible lightning threats to Shuttle Payload components together with specifications for protection of these components, result from the calculation of lightning induced electric and magnetic fields inside and outside the during a lightning event. These fields also induce currents and voltages on cables and circuits which may be connected to, or a part of, shuttle payload components. These currents and voltages are also calculated. These threat levels are intended as a guide for designers of payload equipment to specify any shielding and/or lightning protection mitigation which may be required for payload components which are in the process of preparation or being transferred into the Shuttle Orbiter.

  10. Jet Stream Interrupter Gap Lightning Protection Device for 35 kV Overhead Transmission Lines%35kV架空输电线路间隙灭弧的研究

    Institute of Scientific and Technical Information of China (English)

    王巨丰; 黄维; 曲振旭; 刘儒

    2012-01-01

    To address the problem of lightning stroke on 35 kV overhead transmission lines, a jet stream interrupter gap lightning protection device (JSGLPD) for 35 kV overhead transmission lines was developed. When a lightning stroke on the transmission line causes AC flashover on insulator strings, the device is able to quickly cut off the power frequency freewheeling arc to effectively protect the insulator strings against ablation of the power frequency arc. The JSGLPD can achieve the function of limiting the external over-voltage on insulators and avoiding frequent tripping of circuit breaker. Moreover, the movement characteristics of electric arc in jet stream were investigated on the basis of an arc model, in which the arc is assumed to be a chain of small rigid cylindrical current elements, and the arc quenching process was discussed. In addition, a high speed camera system and an oscillograph were used to observe the changes in the current of arc, and the result shows that the arc can be cut off instantly by the high-speed air jet stream.%为解决35 kV架空输电线路的雷击问题,研制了在35 kV架空输电线路上的防雷保护间隙喷射气流灭弧装置.该装置运用了“瞬时疏导”的防雷理念,能够在线路发生雷击闪络时有效地保护绝缘子串免受工频电弧的灼烧,在疏导雷电能量后能够迅速切断工频续流电弧,实现既可以限制绝缘子的外部过电压又可以避免断路器频繁跳闸的功能.笔者在链式电弧模型的基础上结合激波理论研究喷射气流条件下电弧的运动,对电弧的熄灭过程进行了讨论.在高压试验中借助高速摄像机和数字示波器,获取了在高速气流作用下电弧被迅速熄灭的过程图像和数据.

  11. Explore the Technical and Maintenance of Transmission Lines Lightning Protection Measures%输电线路防雷技术及维护措施探讨

    Institute of Scientific and Technical Information of China (English)

    郭志刚

    2014-01-01

    电力资源对社会的进步和发展起着非常大的促进作用。我国地域广阔,输电线路十分复杂,在对电力输电线路产生影响的诸多因素中,雷击是影响输电线路安全的关键。结合学习和工作实践经验,对输电线路防雷技术及其维护措施进行了分析,并提出了粗浅的建议。%Electric power resource of social progress and development plays a great role in promoting. China's vast, transmission lines is very complex, many factors have an impact on electricity transmission lines, and lightning is the key to safe power transmission line impact. Combining study and work experience, technology and transmission lines lightning maintenance measures were analyzed, and made superficial recommendations.

  12. 电子信息系统工程中防雷接地探讨%Electronic Information Systems Engineering Lightning Protection and Grounding Discussion

    Institute of Scientific and Technical Information of China (English)

    徐宝春; 徐亚东

    2014-01-01

    随着信息与控制技术的飞速发展,电子信息系统日益增加,这些电子信息系统中的电子器件的集成和超大规模集成化,普遍存在着绝缘强度低、过电压耐受能力差等弱点。雷电对这些电子设备潜伏着严重的不安全性,一旦发生雷击事件,导致信息系统无法实时对外提供服务,将造成不可估量的直接与间接的经济损失和影响。%With the rapid development of information and control technology, electronic information systems increasing integration and ultra-large-scale integration, the prevalence of low dielectric strength of these electronic information system of electronic devices, over-voltage tolerance of poor weakness. Lightning serious of these electronic devices lurking insecurity, once lightning incident occurred not real-time information systems to provide services, it will cause immeasurable direct and indirect economic loss and impact.

  13. Lightning detection in planetary atmospheres

    CERN Document Server

    Aplin, Karen L

    2016-01-01

    Lightning in planetary atmospheres is now a well-established concept. Here we discuss the available detection techniques for, and observations of, planetary lightning by spacecraft, planetary landers and, increasingly, sophisticated terrestrial radio telescopes. Future space missions carrying lightning-related instrumentation are also summarised, specifically the European ExoMars mission and Japanese Akatsuki mission to Venus, which could both yield lightning observations in 2016.

  14. Lightning medicine in South Africa.

    Science.gov (United States)

    Blumenthal, Ryan; Trengrove, Estelle; Jandrell, Ian R; Saayman, Gert

    2012-06-06

    South Africa has a rich history of lightning research; however, research on the clinical and pathological effects and features of lightning-related injury (keraunomedicine or lightning medicine) remains neglected locally. By providing an overview of keraunomedicine and focussing on South African perspectives, we hope to raise awareness and propose that a concerted and co-ordinated attempt be made to report and collate data regarding lightning strike victims in South Africa.

  15. A review of advances in lightning observations during the past decade in Guangdong, China

    Science.gov (United States)

    Zhang, Yijun; Lü, Weitao; Chen, Shaodong; Zheng, Dong; Zhang, Yang; Yan, Xu; Chen, Lüwen; Dong, Wansheng; Dan, Jianru; Pan, Hanbo

    2016-08-01

    This paper reviews recent advances in understanding the physical processes of artificially triggered lightning and natural lightning as well as the progress in testing lightning protection technologies, based on a series of lightning field campaigns jointly conducted by the Chinese Academy of Meteorological Sciences and Guangdong Meteorological Bureau since 2006. During the decade-long series of lightning field experiments, the technology of rocket-wire artificially triggered lightning has been improved, and has successfully triggered 94 lightning flashes. Through direct lightning current waveform measurements, an average return stroke peak current of 16 kA was obtained. The phenomenon that the downward leader connects to the lateral surface of the upward leader in the attachment process was discovered, and the speed of the upward leader during the connection process being significantly greater than that of the downward leader was revealed. The characteristics of several return strokes in cloud-to-ground lighting have also been unveiled, and the mechanism causing damage to lightning protection devices (i.e., ground potential rise within the rated current) was established. The performance of three lightning monitoring systems in Guangdong Province has also been quantitatively assessed.

  16. Lightning incidents in Mongolia

    Directory of Open Access Journals (Sweden)

    Myagmar Doljinsuren

    2015-11-01

    Full Text Available This is one of the first studies that has been conducted in Mongolia on the distribution of lightning incidents. The study covers a 10-year period from 2004 to 2013. The country records a human death rate of 15.4 deaths per 10 million people per year, which is much higher than that of many countries with similar isokeraunic level. The reason may be the low-grown vegetation observed in most rural areas of Mongolia, a surface topography, typical to steppe climate. We suggest modifications to Gomes–Kadir equation for such countries, as it predicts a much lower annual death rate for Mongolia. The lightning incidents spread over the period from May to August with the peak of the number of incidents occurring in July. The worst lightning affected region in the country is the central part. Compared with impacts of other convective disasters such as squalls, thunderstorms and hail, lightning stands as the second highest in the number of incidents, human deaths and animal deaths. Economic losses due to lightning is only about 1% of the total losses due to the four extreme weather phenomena. However, unless precautionary measures are not promoted among the public, this figure of losses may significantly increase with time as the country is undergoing rapid industrialization at present.

  17. Exploring Lightning Jump Characteristics

    Science.gov (United States)

    Chronis, Themis; Carey, Larry D.; Schultz, Christopher J.; Schultz, Elise; Calhoun, Kristin; Goodman, Steven J.

    2014-01-01

    This study is concerned with the characteristics of storms exhibiting an abrupt temporal increase in the total lightning flash rate (i.e., lightning jump, LJ). An automated storm tracking method is used to identify storm "clusters" and total lightning activity from three different lightning detection systems over Oklahoma, northern Alabama and Washington, D.C. On average and for different employed thresholds, the clusters that encompass at least one LJ (LJ1) last longer, relate to higher Maximum Expected Size of Hail, Vertical Integrated Liquid and lightning flash rates (area-normalized) than the clusters that did not exhibit any LJ (LJ0). The respective mean values for LJ1 (LJ0) clusters are 80 min (35 min), 14 mm (8 mm), 25 kg per square meter (18 kg per square meter) and 0.05 flash per min per square kilometer (0.01 flash per min per square kilometer). Furthermore, the LJ1 clusters are also characterized by slower decaying autocorrelation functions, a result that implies a less "random" behavior in the temporal flash rate evolution. In addition, the temporal occurrence of the last LJ provides an estimate of the time remaining to the storm's dissipation. Depending of the LJ strength (i.e., varying thresholds), these values typically range between 20-60 min, with stronger jumps indicating more time until storm decay. This study's results support the hypothesis that the LJ is a proxy for the storm's kinematic and microphysical state rather than a coincidental value.

  18. The start of lightning: Evidence of bidirectional lightning initiation

    Science.gov (United States)

    Montanyà, Joan; van der Velde, Oscar; Williams, Earle R.

    2015-10-01

    Lightning flashes are known to initiate in regions of strong electric fields inside thunderstorms, between layers of positively and negatively charged precipitation particles. For that reason, lightning inception is typically hidden from sight of camera systems used in research. Other technology such as lightning mapping systems based on radio waves can typically detect only some aspects of the lightning initiation process and subsequent development of positive and negative leaders. We report here a serendipitous recording of bidirectional lightning initiation in virgin air under the cloud base at ~11,000 images per second, and the differences in characteristics of opposite polarity leader sections during the earliest stages of the discharge. This case reveals natural lightning initiation, propagation and a return stroke as in negative cloud-to-ground flashes, upon connection to another lightning channel - without any masking by cloud.

  19. Examination of Height of Transmission Line and Lightning Striking Distance concerning Lightning Shielding Effect Prediction

    Science.gov (United States)

    Sakata, Tadashi; Yamamoto, Kazuo; Sekioka, Shozo; Yokoyama, Shigeru

    We examined the lightning frequency reported by Eriksson and the lightning current distribution shown in IEC 62305-1. The lightning striking coefficient is assumed to be related to height of structures. The lightning current distribution to ground which was applicable to the electro-geometric model is estimated. Using the assumption of lightning striking distance coefficient and the estimated lightning current distribution, we calculated the lightning frequency and the lightning current distribution, concerning lightning shielding effect in transmission lines. The calculation results of the lightning frequency and the lightning current distributions were compared with the observation results, and agree satisfactorily with them.

  20. Lightning not detected on Titan

    Science.gov (United States)

    Tretkoff, Ernie

    2011-05-01

    Scientists have speculated that lightning on Saturn's moon Titan could produce changes in atmospheric chemistry and could even spark production of organic compounds that could be precursors to the evolution of life, but so far there has been no conclusive detection of lightning on Titan. Extending previous searches for lightning on Titan, Fischer and Gurnett analyzed radio data up to the 72nd close flyby of Titan by the Cassini spacecraft. They found no evidence of lightning and concluded that if lightning occurs at all on Titan, it is probably a very rare event. (Geophysical Research Letters, doi:10.1029/2011GL047316, 2011)

  1. 浅谈防雷装置对环境安全的影响%Discussion about Influence of Environment Safety Caused by Lightning Protection Equipment

    Institute of Scientific and Technical Information of China (English)

    吕许君; 钟国明; 王涪德

    2011-01-01

    The causes of waking wohage & touch voltage and their harms to people and livestock were analyzed to arouse the attention for the details of the grounding system construction. The measures to prevent the accident caused by waking voltage & touch voltage were summarized, to reduce the lightning strike injury as far as possible.%通过分析跨步电压和接触电压的成因及它们对人畜的危害。以此引起人们对接地装置施工细节的重视。最后总结出防止跨步电压和接触电压事故的措施。希望尽可能减少由此造成的雷击伤人事故。

  2. Application Investigation on Parallel Gap Lightning Protection Device of Composite Insulators for 110 kV Transmission Line%110kV线路复合绝缘子防雷保护并联间隙的应用研究

    Institute of Scientific and Technical Information of China (English)

    陈锡阳; 尹创荣; 葛栋; 张翠霞; 王献丽; 贺子鸣; 杨挺; 王伟然

    2012-01-01

    笔者介绍东莞供电局110 kV线路复合绝缘子防雷保护并联间隙的应用研究成果,对安装并联间隙后线路雷电性能进行计算,对其引导雷电放电、转移疏导工频电弧、均匀工频电场3种功能加以试验验证,并介绍所研制的110 kV线路复合绝缘子防雷保护并联间隙的现场运行情况.研究结果表明,设计的110 kV输电线路复合绝缘子用并联间隙满足要求,现场运行情况良好,能够作为现有防雷措施的有利补充,具有广阔的应用前景.%The application investigation on parallel gap lightning protection device of composite insulators for the 110 kV overhead transmission line used in Dongguan Power Supply Company is present in this article. The lightning performance calculation after the installation of parallel gap device is carried out. The functions of its guiding lightning discharge,transferring power frequency arc,uniforming power frequency electric field are verified by tests. The operation situation of the 110 kV line parallel gap lightning protection of composite insulator is introduced. The results show that the designs of the parallel gap for 110 kV transmission line composite insulators meet the requirements. The parallel gap is in good on-site operation condition, which can be used as the positive complement the existing lightning protection measures, and has broad application prospects.

  3. Analysis on Lightning Surge Propagation in Wind Farm

    Science.gov (United States)

    Yasuda, Yoh; Hara, Takehisa; Funabashi, Toshihisa

    Wind power generation is expected to become more important in the future distribution system. Although several prospective reports such as IEC 61400-24 and NREL SR-500-31115 indicate on insulation scheme and grounding design for lightning protection, it still seems that there are not many investigations on the problems. This paper therefore discusses lightning surge analysis using wind farm model with 2 or 10 ideal wind turbines. Changing parameters such as grounding resistance and lightning strike points, several cases were studied. As the result of the analysis using digital simulator ARENE, it is clear that the surge tends to propagate toward the end of a distribution line in a wind farm and there is possibility of insulation accidents at the other wind turbines when lightning attacks a wind turbine.

  4. High-altitude electrical discharges associated with thunderstorms and lightning

    Science.gov (United States)

    Liu, Ningyu; McHarg, Matthew G.; Stenbaek-Nielsen, Hans C.

    2015-12-01

    The purpose of this paper is to introduce electrical discharge phenomena known as transient luminous events above thunderstorms to the lightning protection community. Transient luminous events include the upward electrical discharges from thunderstorms known as starters, jets, and gigantic jets, and electrical discharges initiated in the lower ionosphere such as sprites, halos, and elves. We give an overview of these phenomena with a focus on starters, jets, gigantic jets, and sprites, because similar to ordinary lightning, streamers and leaders are basic components of these four types of transient luminous events. We present a few recent observations to illustrate their main properties and briefly review the theories. The research in transient luminous events has not only advanced our understanding of the effects of thunderstorms and lightning in the middle and upper atmosphere, but also improved our knowledge of basic electrical discharge processes critical for sparks and lightning.

  5. Applications of triggered lightning to space vehicle operations

    Science.gov (United States)

    Jafferis, William; Sanicandro, Rocco; Rompalla, John; Wohlman, Richard

    1992-11-01

    Kennedy Space Center (KSC) and the USAF Eastern Space Missile Center (ESMC) covering an area of 25 x 40 km are frequently called America's Spaceport. This title is earned through the integration, by labor and management, of many skills in a wide variety of engineering fields to solve many technical problems that occur during the launch processing of space vehicles. Weather is one of these problems, and although less frequent in time and duration when compared to engineering type problems, has caused costly and life threatening situations. This sensitivity to weather, especially lightning, was recognized in the very early pioneer days of space operations. The need to protect the many v\\facilities, space flight hardware, and personnel from electrified clouds capable of producing lightning was a critical element in improving launch operations. A KSC lightning committee was formed and directed to improve lightning protection, detection, and measuring systems and required that all theoretical studies be confirmed by KSC field data. Over the years, there have been several lightning incidents involving flight vehicles during ground processing as well as launch. Subsequent investigations revealed the need to improve these systems as well as the knowledge of the electrical atmosphere and its effects on operations in regard to cost and safety. Presented here is how, KSC Atmospheric Science Field Laboratory (AFSL), in particular Rocket Triggered Lightning, is being used to solve these problems.

  6. Lightning Imaging with LOFAR

    Directory of Open Access Journals (Sweden)

    Scholten Olaf

    2017-01-01

    Full Text Available We show that LOFAR can be used as a lightning mapping array with a resolution that is orders of magnitude better than existing arrays. In addition the polarization of the radiation can be used to track the direction of the stepping discharges.

  7. The Origin of Lightning.

    Science.gov (United States)

    Weewish Tree, 1979

    1979-01-01

    A heavenly source gives an orphaned Cherokee boy 12 silver arrows and directs him to kill the chief of the cruel Manitos (spirits). When the boy fails in his mission, the angry Manitos turn him into lightning, condemning him to flash like his silver arrows across the skies forever. (DS)

  8. On peculiarities of the method for determining the probability of lightning striking terrestrial explosive objects

    Science.gov (United States)

    Gundareva, S. V.; Kalugina, I. E.; Temnikov, A. G.

    2016-10-01

    We have described a new probabilistic method for calculating and assessing lightning striking terrestrial explosive objects using a combined criterion for the emergence of upward streamer and leader discharges from the elements of the object being protected and lightning rods taking into account the probabilistic nature of the avalanche-streamer and streamer-leader transitions, the trajectories of a downward stepped lightning leader and lightning current. It has been shown that the disregard of possible formation of uncompleted streamer discharges from the elements of the object in the electric field of a downward lightning leader, which can ignite explosive emission, decreases the rated probability of the object being damaged by a lightning stroke by several times.

  9. Analysis and Assessment of Peak Lightning Current Probabilities at the NASA Kennedy Space Center

    Science.gov (United States)

    Johnson, D. L.; Vaughan, W. W.

    1999-01-01

    This technical memorandum presents a summary by the Electromagnetics and Aerospace Environments Branch at the Marshall Space Flight Center of lightning characteristics and lightning criteria for the protection of aerospace vehicles. Probability estimates are included for certain lightning strikes (peak currents of 200, 100, and 50 kA) applicable to the National Aeronautics and Space Administration Space Shuttle at the Kennedy Space Center, Florida, during rollout, on-pad, and boost/launch phases. Results of an extensive literature search to compile information on this subject are presented in order to answer key questions posed by the Space Shuttle Program Office at the Johnson Space Center concerning peak lightning current probabilities if a vehicle is hit by a lightning cloud-to-ground stroke. Vehicle-triggered lightning probability estimates for the aforementioned peak currents are still being worked. Section 4.5, however, does provide some insight on estimating these same peaks.

  10. Science of Ball Lightning (Fire Ball)

    Science.gov (United States)

    Ohtsuki, Yoshi-Hiko

    1989-08-01

    The Table of Contents for the full book PDF is as follows: * Organizing Committee * Preface * Ball Lightning -- The Continuing Challenge * Hungarian Ball Lightning Observations in 1987 * Nature of Ball Lightning in Japan * Phenomenological and Psychological Analysis of 150 Austrian Ball Lightning Reports * Physical Problems and Physical Properties of Ball Lightning * Statistical Analysis of the Ball Lightning Properties * A Fluid-Dynamical Model for Ball Lightning and Bead Lightning * The Lifetime of Hill's Vortex * Electrical and Radiative Properties of Ball Lightning * The Candle Flame as a Model of Ball Lightning * A Model for Ball Lightning * The High-Temperature Physico-Chemical Processes in the Lightning Storm Atmosphere (A Physico-Chemical Model of Ball Lightning) * New Approach to Ball Lightning * A Calculation of Electric Field of Ball Lightning * The Physical Explanation to the UFO over Xinjiang, Northern West China * Electric Reconnection, Critical Ionization Velocity, Ponderomotive Force, and Their Applications to Triggered and Ball Lightning * The PLASMAK™ Configuration and Ball Lightning * Experimental Research on Ball Lightning * Performance of High-Voltage Test Facility Designed for Investigation of Ball Lightning * List of Participants

  11. Attempts to Create Ball Lightning with Triggered Lightning

    Science.gov (United States)

    2009-10-01

    fluids, solids, and vegetation , as described in the next section. The experiments were performed during Summer 2008 at the International Center for... filters were used on all 35 mm cameras to prevent over-exposure. There were a total of eight successful triggered lightning events during the ball...Dinnis, Ball Lightning Caused by Oxidation of Nanoparticle Networks from Normal Lightning Strikes in Soil, Nature 403, 519-521, 2000 Paiva, G. and Pavão

  12. Industrial accidents triggered by lightning.

    Science.gov (United States)

    Renni, Elisabetta; Krausmann, Elisabeth; Cozzani, Valerio

    2010-12-15

    Natural disasters can cause major accidents in chemical facilities where they can lead to the release of hazardous materials which in turn can result in fires, explosions or toxic dispersion. Lightning strikes are the most frequent cause of major accidents triggered by natural events. In order to contribute towards the development of a quantitative approach for assessing lightning risk at industrial facilities, lightning-triggered accident case histories were retrieved from the major industrial accident databases and analysed to extract information on types of vulnerable equipment, failure dynamics and damage states, as well as on the final consequences of the event. The most vulnerable category of equipment is storage tanks. Lightning damage is incurred by immediate ignition, electrical and electronic systems failure or structural damage with subsequent release. Toxic releases and tank fires tend to be the most common scenarios associated with lightning strikes. Oil, diesel and gasoline are the substances most frequently released during lightning-triggered Natech accidents.

  13. Research on Lightning Protection of 220 kV Power Supply Lines of Double-circuit Railway Traction Station on the Same Tower and Improvement Strategy%220 kV 同塔双回铁路牵引站供电线路防雷问题及改进策略研究

    Institute of Scientific and Technical Information of China (English)

    周华敏; 王锐; 周原; 彭向阳; 顾温国

    2015-01-01

    Aiming at the problem of frequent lightning tripping of 220 kV power supply lines of double-circuit railway trac-tion station on the same tower,reason for tripping was summarized and analyzed and pertinent improvement was made com-bining existing lightning protection measures.Idle conductors were transformed into coupling grounding wires and electro-magnetic transient simulation software ATP/EMTP was used for working out lightning back-flashover level of the tower so as to determine optimal way to transform the upper phase conductor.Differentiation lightning protection strategy was used, configuration way of line arresters was optimized and simultaneous tripping ability to prevent lightning of double-circuit lines were improved.Air gap distance between jumper wires and tower cross arm was adjusted to meet operational demand and jumper wire strings or windage protection insulators were increased considering of wind protection requirement.Grounding resistance of lines was generally surveyed and grounding devices of the tower in those areas with high earth resistivity and high ground flash density were preferentially transformed for reducing resistance.By means of using above comprehensive transformation measures for lightning protection and differentiation lightning protection,performance of lightning protec-tion of 220 kV power supply lines of double-circuit railway traction station on the same tower might be greatly improved.%针对220 kV 同塔双回铁路牵引站供电线路自投运以来频繁发生雷击跳闸问题,总结分析跳闸原因,结合线路已有防雷措施,进行有针对性的改进。将闲置导线改造为耦合地线,并利用电磁暂态仿真软件 ATP/EMTP计算杆塔反击耐雷水平,确定对上相导线进行改造的最佳方式;采取差异化防雷策略,优化线路避雷器配置方式,提高双回线路防雷击同时跳闸能力;调整跳线与铁塔横担空气间隙距离以满足运行要求,同时结合防风需要,

  14. Lightning Initiation and Propagation

    Science.gov (United States)

    2009-08-22

    measured by the Thunderstorm Energetic Radiation Array ( TERA ), J. Geophys. Res, Vol. 114, accepted for publication, Z. Saleh, 1. Dwyer,1. Howard, M...triggered lightning as measured by the Thunderstorm Energetic Radiation Array ( TERA ), 1. Geophys. Res. VoL 114 accepted for publication, Z. Saleh, 1. Dwyer, 1...Howard, M. Uman, M. Bakhtiari, D. Concha, M. Stapleton, D. Hill, C. Biagi, and H. Rassoul Abstract The Thunderstorm Energetic Radiation Array ( TERA

  15. TRIP illumines lightning

    Science.gov (United States)

    Hill, R. D.

    It is 8 yr since important measurements of lightning in single-cell thunderstorms were made during the Thunderstorm Research International Project (TRIP), yet no theoretical interpretation of the lightning generation mechanism from the data has been made. This tardiness in interpreting the data is undoubtedly related to the existing confusion in lightning generation theories.According to Chalmers [1967], there are two classes of thunderstorm charge separation theories: those that rely on gravitation and those that do not involve gravitation. In the gravitational class, Chalmers again distinguished two types of processes: those in which ions are naturally generated (e.g., by cosmic rays, etc.) and are then attached to particles in the cloud and those in which some process (e.g., collision, coagulation, etc.) generates positive and negatively charged particles from neutrals in the cloud. Some of these two process types, cited in Chalmers' work, are given in Table 1, together with some of the scientists who originally proposed these processes.

  16. The Power of the Point: Benjamin Franklin, the Lightning Rod and Two Misconceptions That Have Plagued Us to This Day

    Science.gov (United States)

    Aulich, G. D.; Moore, C. B.; Rison, W.

    2006-12-01

    Most people know that Ben Franklin invented the lightning rod and that his rods have successfully protected structures for over 250 years. What people don't know is that he invented them on the basis of two misconceptions. The first, that an elevated pointed conductor would discharge a thunderstorm, thereby preventing lightning. The second, that, should the first process fail, the elevated conductor, by virtue of its pointed tip, would serve as a preferred receptor for any lightning strokes that did occur. It has long been known that grounded, elevated, pointed conductors can not discharge thunderstorms and experiments conducted at the Langmuir Laboratory during the 1990s have shown that moderately blunt, rather than pointed, rods are the best receptors for lightning strokes. Nevertheless, Franklin's incorrect ideas about lightning rods persist in many minds, even among some people in the lightning protection business.

  17. 14 CFR 193.17 - How must design and production approval holders handle information they receive from the FAA...

    Science.gov (United States)

    2010-01-01

    ... REGULATIONS PROTECTION OF VOLUNTARILY SUBMITTED INFORMATION § 193.17 How must design and production approval... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false How must design and production approval holders handle information they receive from the FAA under this part? 193.17 Section 193.17...

  18. Low voltage lightning arresters. Components. Low voltage grids; Parafoudres basse tension. Composants. Reseaux basse tension

    Energy Technology Data Exchange (ETDEWEB)

    Rousseau, A. [Assistance Protection System SAS, 94 - Cachan (France)

    2003-08-01

    Electrical equipments used in domestic and industrial applications are more and more sensible to overvoltages because of the massive use of electronic components in these equipments and appliances. Overvoltages do not propagate only with power lines but also through phone lines, coaxial cables, data networks, and even through grounding circuits. The informations about low voltage grids, useful for the selection of lightning arresters are presented in this article. In the ideal case, each possible way of input for overvoltage currents must be protected. The components used in lightning arresters have improved for a better reliability, a better energy resistance and a better protection level. These components are also presented in this article: 1 - technical and standard evolution: improvement of the understanding of low voltage phenomena, standards evolution, recall of basic definitions and data about lightning protection; 2 - components: varistors, spark gaps, silicon-based solid components, aging and end of life, decoupling components (thermistors, resistors, inductors); 3 - low voltage grids: different types of energy networks, transmission of overvoltages on low voltage networks (overvoltages due to lightning, or power station actuating, temporary overvoltages), influence of lightning conductors and lightning strikes close to the building structure, statistical data about lightning overvoltages on low voltage grids, protection and risk analysis. (J.S.)

  19. Research on Winter Lightning in Japan

    Science.gov (United States)

    Ishii, Masaru

    Winter lightning in Japan is known for such characteristics as frequent occurrence of upward lightning and of positive ground flashes. On the engineering side, higher frequencies of troubles at transmission lines or wind turbines in winter due to lightning than those in summer have been experienced in the winter thunderstorm area of Japan, despite the much smaller number of lightning strokes in winter observed by lightning location systems (LLS). Such frequent troubles by lightning in the cold season are unique in Japan, which have promoted intensive research on winter lightning in Japan since 1980s.

  20. Lightning and thermal injuries.

    Science.gov (United States)

    Sanford, Arthur; Gamelli, Richard L

    2014-01-01

    Electrical burns are classified as either high voltage (1000 volts and higher) or low voltage (Lightning strikes may conduct millions of volts of electricity, yet the effects can range from minimal cutaneous injuries to significant injury comparable to a high-voltage industrial accident. Lightning strikes commonly result in cardiorespiratory arrest, for which CPR is effective when begun promptly. Neurologic complications from electrical and lightning injuries are highly variable and may present early or late (up to 2 years) after the injury. The prognosis for electricity-related neurologic injuries is generally better than for other types of traumatic causes, suggesting a conservative approach with serial neurologic examinations after an initial CT scan to rule out correctable causes. One of the most common complications of electrical injury is a cardiac dysrhythmia. Because of the potential for large volumes of muscle loss and the release of myoglobin, the presence of heme pigments in the urine must be evaluated promptly. Presence of these products of breakdown of myoglobin and hemoglobin puts the injured at risk for acute renal failure and must be treated. The exact mechanism of nerve injury has not been explained, but both direct injury by electrical current overload or a vascular cause receive the most attention. Because electrical injuries carry both externally visible cutaneous injuries and possible hidden musculoskeletal damage, conventional burn resuscitation formulas based on body surface area injured may not provide enough fluid to maintain urine output. Damaged muscle resulting in swelling within the investing fascia of an extremity may result in compartment syndromes, requiring further attention. If myoglobin has been detected in the urine, treatment is aggressive volume resuscitation and possibly alkalinization of the urine or mannitol is given IV push to minimize pigment precipitation in the renal tubules. Approximately 15% of electrical burn victims

  1. The CHUVA Lightning Mapping Campaign

    Science.gov (United States)

    Goodman, Steven J.; Blakeslee, Richard J.; Bailey, Jeffrey C.; Carey, Lawrence D.; Hoeller, Hartmut; Albrecht, Rachel I.; Morales, Carlos; Pinto, Osmar; Saba, Marcelo M.; Naccarato, Kleber; Hembury, Nikki; Nag, Amitabh; Heckman, Stan; Holzworth, Robert H.; Rudlosky, Scott D.; Betz, Hans-Dieter; Said, Ryan; Rauenzahn, Kim

    2011-01-01

    The primary science objective for the CHUVA lightning mapping campaign is to combine measurements of total lightning activity, lightning channel mapping, and detailed information on the locations of cloud charge regions of thunderstorms with the planned observations of the CHUVA (Cloud processes of tHe main precipitation systems in Brazil: A contribUtion to cloud resolVing modeling and to the GPM (GlobAl Precipitation Measurement) field campaign. The lightning campaign takes place during the CHUVA intensive observation period October-December 2011 in the vicinity of S o Luiz do Paraitinga with Brazilian, US, and European government, university and industry participants. Total lightning measurements that can be provided by ground-based regional 2-D and 3-D total lightning mapping networks coincident with overpasses of the Tropical Rainfall Measuring Mission Lightning Imaging Sensor (LIS) and the SEVIRI (Spinning Enhanced Visible and Infrared Imager) on the Meteosat Second Generation satellite in geostationary earth orbit will be used to generate proxy data sets for the next generation US and European geostationary satellites. Proxy data, which play an important role in the pre-launch mission development and in user readiness preparation, are used to develop and validate algorithms so that they will be ready for operational use quickly following the planned launch of the GOES-R Geostationary Lightning Mapper (GLM) in 2015 and the Meteosat Third Generation Lightning Imager (LI) in 2017. To date there is no well-characterized total lightning data set coincident with the imagers. Therefore, to take the greatest advantage of this opportunity to collect detailed and comprehensive total lightning data sets, test and validate multi-sensor nowcasting applications for the monitoring, tracking, warning, and prediction of severe and high impact weather, and to advance our knowledge of thunderstorm physics, extensive measurements from lightning mapping networks will be collected

  2. Using Total Lightning Observations to Enhance Lightning Safety

    Science.gov (United States)

    Stano, Geoffrey T.

    2012-01-01

    Lightning is often the underrated threat faced by the public when it comes to dangerous weather phenomena. Typically, larger scale events such as floods, hurricanes, and tornadoes receive the vast majority of attention by both the general population and the media. This comes from the fact that these phenomena are large, longer lasting, can impact a large swath of society at one time, and are dangerous events. The threat of lightning is far more isolated on a case by case basis, although millions of cloud-to-ground lightning strikes hit this United States each year. While attention is given to larger meteorological events, lightning is the second leading cause of weather related deaths in the United States. This information raises the question of what steps can be taken to improve lightning safety. Already, the meteorological community s understanding of lightning has increased over the last 20 years. Lightning safety is now better addressed with the National Weather Service s access to the National Lightning Detection Network data and enhanced wording in their severe weather warnings. Also, local groups and organizations are working to improve public awareness of lightning safety with easy phrases to remember, such as "When Thunder Roars, Go Indoors." The impacts can be seen in the greater array of contingency plans, from airports to sports stadiums, addressing the threat of lightning. Improvements can still be made and newer technologies may offer new tools as we look towards the future. One of these tools is a network of sensors called a lightning mapping array (LMA). Several of these networks exist across the United States. NASA s Short-term Prediction Research and Transition Center (SPoRT), part of the Marshall Spaceflight Center, has access to three of these networks from Huntsville, Alabama, the Kennedy Space Center, and Washington D.C. The SPoRT program s mission is to help transition unique products and observations into the operational forecast environment

  3. 2000~2007年输电线路雷击闪络统计分析%Statistics and Analysis of Lightning Flashovers of Transmission Lines During 2000~2007

    Institute of Scientific and Technical Information of China (English)

    李晓岚; 陈家宏; 谷山强

    2009-01-01

    Lightning stroke is one of the important causes of the accidents that occur on transmission lines. With the development of power system, the proportion of outages on transmission lines because of lightning stroke also increases. And according to the lightning accidents results, the lightning stroke characteristics is related to the time factors tightly. In order to analyze the correlativity between the lightning flashover amount and the time factors, about 425 times lightning flashover on 187 lines in l0 power supply companies of 220 kV and 500 kV transmission lines during 2000~2007 are investigated in this paper. The correlativity between the lightning flashover amount and the time factors is analyzed. According to the lightning stroke accidents investigation records, the lightning flashover amount of transmission line increases from the year of 2000 to 2007. In each year lightning flashovers mostly happen in the month of June, July and August. Similarly in each day the flashover amount also varies with the time of day obviously. These lightning flashovers mainly occur during 14:00~21:00 in the afternoon. The analysis results in this paper have a good agreement with the meteorological observations and lightning detection data of lightning location system (LLS). And these results provide good reference for the lightning protection work in power system.

  4. A stepped leader model for lightning including charge distribution in branched channels

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Wei; Zhang, Li [School of Electrical Engineering, Shandong University, Jinan 250061 (China); Li, Qingmin, E-mail: lqmeee@ncepu.edu.cn [Beijing Key Lab of HV and EMC, North China Electric Power University, Beijing 102206 (China); State Key Lab of Alternate Electrical Power System with Renewable Energy Sources, Beijing 102206 (China)

    2014-09-14

    The stepped leader process in negative cloud-to-ground lightning plays a vital role in lightning protection analysis. As lightning discharge usually presents significant branched or tortuous channels, the charge distribution along the branched channels and the stochastic feature of stepped leader propagation were investigated in this paper. The charge density along the leader channel and the charge in the leader tip for each lightning branch were approximated by introducing branch correlation coefficients. In combination with geometric characteristics of natural lightning discharge, a stochastic stepped leader propagation model was presented based on the fractal theory. By comparing simulation results with the statistics of natural lightning discharges, it was found that the fractal dimension of lightning trajectory in simulation was in the range of that observed in nature and the calculation results of electric field at ground level were in good agreement with the measurements of a negative flash, which shows the validity of this proposed model. Furthermore, a new equation to estimate the lightning striking distance to flat ground was suggested based on the present model. The striking distance obtained by this new equation is smaller than the value estimated by previous equations, which indicates that the traditional equations may somewhat overestimate the attractive effect of the ground.

  5. Lightning and Gunpowder in the 18th Century

    Science.gov (United States)

    Krider, E. P.

    2006-12-01

    On or before June, 1751, Benjamin Franklin and co-workers showed that gunpowder could be ignited by a small electric spark, and subsequently people used gunpowder to enhance the explosions of "thunder houses" to demonstrate that grounded metallic rods would protect model structures against lightning damage. Even before the sentry box and kite experiments proved that thunderclouds are electrified and that lightning is an electrical discharge in 1752, Franklin had hypothesized that a tall, well-grounded conductor might reduce or prevent lightning damage by silently discharging the cloud, and if a discharge did occur, then the tall rod would offer a preferred place for the lightning to strike, and the grounding conductors would guide the current into the ground in a harmless fashion. Over the next 10 years, experience gained through practice showed that grounded rods did indeed protect ordinary structures from lightning damage, but a question remained about the best way to protect gunpowder magazines. In 1762, Franklin recommended a tall "mast not far from it, which may reach 15 or 20 feet above the top of it, with a thick iron rod in one piece fastened to it, pointed at the highest end, and reaching down through the earth till it comes to water," and in 1772 he made a similar recommendation for protecting the British powder magazine at Purfleet. In 1780, Jan Ingenhousz asked Franklin to "communicate to me some short hints, which may occur to you about the most convenient manner of constructing gun powder magazines, the manner of preserving the powder from moisture and securing the building in the best manner from the effects of lightning." In his reply, Franklin detailed a method of protection that is almost perfect, "they should be constructed in the Ground; that the Walls should be lin'd with Lead, the Floor Lead, all 1/4 Inch thick & the Joints well solder'd; the Cover Copper; with a little Scuttle to enter, the whole in the Form of a Canister for Tea. If the

  6. Lightning Observations with the Upgraded Lanmguir Lab Lightning Mapping Array

    Science.gov (United States)

    Rison, W.; Krehbiel, P. R.; Hunyady, S.; Edens, H. E.; Aulich, G. D.

    2010-12-01

    The Langmuir Lab Lightning Mapping Array (LMA) is located on and around the Magdalena Mountains in central New Mexico. Recently there have been several improvements to the LMA which have dramatically increased its sensitivity. By switching most stations to solar power (which allows us to place them far from buildings and power lines) and reducing the noise of the power supply, the station-generated and local environmental noise has been reduced to levels near the theoretical thermal value. Because of the recent switch to digital television, the LMA is no longer degraded by the anthropogenic noise of distant VHF television transmitters, due to the stations mostly being switched to UHF. The distant interference was a particularly bad problem for the stations located high in the Magdalena Mountains. The combination of lower threshold values and increasing the number of stations to 16 enables lower-power sources to be detected above the local noise levels and hence located by the system. We are now able to observe the positive leaders (which produce a much lower level of VHF radiation than negative leaders) which propagate upward from a triggering rocket. Lightning channels in natural lightning discharges are also much more clearly defined than in the past. Minor discharges (with one or a few LMA-detected sources) between larger lightning flashes are routinely observed. Much more detail is observed from distant lightning discharges. (However, the increased sensitivity does not reduce the vertical and radial errors for lightning observed outside the array.) In addition to the more sensitive LMA, we continue to improve our array of high-resolution electrostatic field change stations, which provides considerable information on lightning-induced charge transfer. We will present examples of observations of natural and triggered lightning, showing the increased detail now available from the recent improvements to the Langmuir Lab LMA.

  7. Variation in Regional and Global Lightning

    Science.gov (United States)

    Holzworth, R. H., II; Brundell, J. B.; McCarthy, M.; Virts, K.; Hutchins, M. L.; Jacobson, A. R.; Heckman, S.

    2015-12-01

    Daily global lightning variation over oceans and orography, caused by major weather patterns such as typhoons and seasonal weather oscillations, are determined with high time resolution. Observations of strong variations in global lightning are used to study possible variations in magnetospheric particle densities. Strong lightning patterns associated with ocean currents are demonstrated with a study of the Gulf Stream. We located all major lightning producing storms, using a clustering algorithm on 10 years of World Wide Lightning Location Network (WWLLN) data to reduce the influence of rapidly increasing lightning network detection efficiency on temporal studies. The clustered storms are used to study the variations and patterns of global and regional lightning activity. WWLLN and Earth Networks lightning detection networks have been used to show the energy per flash of lightning over the oceans is higher than over land, and the sharp contrast at the coasts will be examined.

  8. 2016 T Division Lightning Talks

    Energy Technology Data Exchange (ETDEWEB)

    Ramsey, Marilyn Leann [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Adams, Luke Clyde [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Ferre, Gregoire Robing [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Grantcharov, Vesselin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Iaroshenko, Oleksandr [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Krishnapriyan, Aditi [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Kurtakoti, Prajvala Kishore [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Le Thien, Minh Quan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Lim, Jonathan Ng [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Low, Thaddeus Song En [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Lystrom, Levi Aaron [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Ma, Xiaoyu [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Nguyen, Hong T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Pogue, Sabine Silvia [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Orandle, Zoe Ann [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Reisner, Andrew Ray [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Revard, Benjamin Charles [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Roy, Julien [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Sandor, Csanad [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Slavkova, Kalina Polet [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Weichman, Kathleen Joy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Wu, Fei [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Yang, Yang [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division

    2016-11-29

    These are the slides for all of the 2016 T Division lightning talks. There are 350 pages worth of slides from different presentations, all of which cover different topics within the theoretical division at Los Alamos National Laboratory (LANL).

  9. Lightning Caused Fires and Acres

    Data.gov (United States)

    Bureau of Land Management, Department of the Interior — Number of wildland fires and acres burned as a result of lightning, from 2001 through 2008 (updated annually). Displayed by the eleven Geographic Areas used by the...

  10. Full scale lightning test technique

    Science.gov (United States)

    Walko, L. C.; Schneider, J. G.

    1980-01-01

    A test technique was developed for applying a full scale mean value (30 kiloampere peak) simulated lightning return stroke current on a complete flight ready aircraft to assess the threat of lightning to aircraft electrical circuits. A computer-aided generator design was used to establish the parameters of the test system. Data from previous work done on development of low inductance current paths determined the basic system configuration.

  11. A LIGHTNING CONDUCTOR MONITORING SYSTEM BASED ON A WIRELESS SENSOR NETWORK

    Directory of Open Access Journals (Sweden)

    Jan Mikeš

    2013-12-01

    Full Text Available Automated heating, lighting and irrigation systems are nowadays standard features of industrial and commercial buildings, and are also increasingly found in ordinary housing. In addition to the benefits of user comfort, automated technology for buildings saves energy and, above all, it provides enhanced protection against leakage of water and hazardous gases, and against fire hazards. Lightning strikes are a natural phenomenon that poses a significant threat to the safety of buildings. The statistics of the Fire and Rescue Service of the Czech Republic show that buildings are in many cases inadequately protected against lightning strikes, or that systems have been damaged by previous strikes. A subsequent strike can occur within the period between regular inspections, which are normally made at intervals of 2–4 years. Over the whole of Europe, thousands of buildings are subjected to the effects of direct lightning strikes each year. This paper presents ways to carry out wireless monitoring of lightning strikes on buildings and to deal with their impact on lightning conductors. By intervening promptly (disconnecting the power supply, disconnecting the gas supply, sending an engineer to inspect the structure, submitting a report to ARC, etc. we can prevent many downstream effects of direct lightning strikes on buildings (fires, electric shocks, etc. This paper introduces a way to enhance contemporary home automation systems for monitoring lightning strikes based on wireless sensor networks technology.

  12. Lightning in superconductors.

    Science.gov (United States)

    Vestgården, J I; Shantsev, D V; Galperin, Y M; Johansen, T H

    2012-01-01

    Crucially important for application of type-II superconductor films is the stability of the vortex matter--magnetic flux lines penetrating the material. If some vortices get detached from pinning centres, the energy dissipated by their motion will facilitate further depinning, and may trigger a massive electromagnetic breakdown. Up to now, the time-resolved behaviour of these ultra-fast events was essentially unknown. We report numerical simulation results revealing the detailed dynamics during breakdown as within nanoseconds it develops branching structures in the electromagnetic fields and temperature, with striking resemblance of atmospheric lightning. During a dendritic avalanche the superconductor is locally heated above its critical temperature, while electrical fields rise to several kV/m as the front propagates at instant speeds near up to 100 km/s. The numerical approach provides an efficient framework for understanding the ultra-fast coupled non-local dynamics of electromagnetic fields and dissipation in superconductor films.

  13. Lightning Imaging via VHF Emission

    Science.gov (United States)

    Kawasaki, Z.

    2015-12-01

    Osaka University has been developing interferometric lightning mapping systems for some time, first with narrow band VHF interferometers, and then with broadband digital VHF interferometers (DITF). Recently, a collaboration between New Mexico Tech and Osaka University resulted in the development of the NMT INTF. All of these interferometric lightning mapping systems have added greatly to our understanding of lightning physics. The next generation of digital broadband VHF interferometer is now being developed in Osaka, called the Lightning Imaging via VHF Emission (LIVE) interferometer. LIVE is capable of mapping lightning in real-time with sub-millisecond time resolution, or through post processing with sub-microsecond time resolution. Near-field corrections have been developed, so that sources very close to the array can be located accurately, and so that the baselines can lengthened for improved angular resolution. LIVE is capable of locating lighting over more than a 75 dB range of brightnesses, allowing the system to be extremely sensitive, and the long baselines allow for location uncertainties as low as tens of meters. Presented are observations of lightning recorded in the Kasai area of Japan, as well as the Pengerang region of Malaysia showing the capabilities of the LIVE interferometer.

  14. 车载通信系统电源对感应雷击的防护研究%Indirect Lightning Protection on Power of Vehicle Communication System

    Institute of Scientific and Technical Information of China (English)

    梁亚冲

    2007-01-01

    首先建立了雷电流的模型,并对雷电流的时域和频域特征进行分析,通过计算典型雷电流对车载通信系统电源线上的感应电压,进而确定了带有天线的车载通信系统防雷区域以及相应的浪涌保护器(SPD-Surge Protective Device)的通流量、残压等相关技术指标,并对SPD的电路以及安装进行了相应的设计.

  15. Competition Mechanism of Lightning Upward Leaders Issued from UHVDC Transmission Lines

    Institute of Scientific and Technical Information of China (English)

    SHI Wei; LI Qingmin; LU Xinchang; ZOU Liang; SUN Qiuqin

    2012-01-01

    Research on the lightning shielding failure characteristics of UHVDC transmission lines is important for adequate transmission line protection and safe operation of a power grid. Focusing the competition characteristics of upward leaders in the lightning attachment process, this work provides technical reference for efficient evaluations of lightning shielding failures and reliable lightning protection designs of UHVDC transmission lines. The charge simulation method is employed to calculate electric field distributions. Based on the calculation and some data obtained by recent long-gap discharge and lightning observations, the effect of several upward leaders starting from UHVDC transmission lines on lightning attachment processes is studied by numerical simulation. The results show that the upward leader inception is delayed, the propagation velocity is smaller, and the propagation direction of the upward leader is changed with interaction among all upward leaders, which influences the selection of lightning striking point. Therefore, in order to improve the accuracy of calculating the lightning shielding failure rate of UHVDC transmission lines, the interaction characteristics of upward leaders should be taken into account . In addition, an analysis of the influence of operating voltage and the protection angle of UHVDC transmission lines based on competition mechanism of upward leaders is made. It is found that the existence of operating voltage mainly affects the ability of the conductor and the overhead ground wire at the same side to incept upward leaders, while the protection angle mainly affects the position of the "starting points" of upward leaders. The results indicate that positive polar conductors should be installed closer to hillsides and the negative protection angle of towers is suggested.

  16. Assessment of Proposed Cab Glass Coating for FAA Control Towers

    Science.gov (United States)

    2015-11-16

    To) Jun 2012 – Jun 2013 4. TITLE AND SUBTITLE Evaluation of Proposed Cab Glass Coating for FAA Control Towers 5a. CONTRACT NUMBER In- House 5b...Lite 2: 12CL N/A C 12"x12"x1 1/2" Insulated; 1/2" STARPHIRE; .060 CLEAR PVB; 1/2" STARPHIRE Bubble Pack Sheet Stuck to Surface N/A D 12...determine if this improvement (if any) degrades over time. Participants: In- house Wright-Patterson personnel and/or FAA-provided “guest

  17. Interaction between Adjacent Lightning Discharges in Clouds

    Institute of Scientific and Technical Information of China (English)

    WANG Yanhui; ZHANG Guangshu; ZHANG Tong; LI Yajun; WU Bin; ZHANG Tinglong

    2013-01-01

    Using a 3D lightning radiation source locating system (LLS),three pairs of associated lightning discharges (two or more adjacent lightning discharges following an arbitrary rule that their space-gap was less than 10 km and their time-gap was less than 800 ms) were observed,and the interaction between associated lightning discharges was analyzed.All these three pairs of associated lightning discharges were found to involve three or more charge regions (the ground was considered as a special charge region).Moreover,at least one charge region involved two lightning discharges per pair of associated lightning discharges.Identified from electric field changes,the subsequent lightning discharges were suppressed by the prior lightning discharges.However,it is possible that the prior lightning discharge provided a remaining discharge channel to facilitate the subsequent lightning discharge.The third case provided evidence of this possibility.Together,the results suggested that,if the charges in the main negative charge region can be consumed using artificial lightning above the main negative charge regions,lightning accidents on the ground could be greatly reduced,on the condition that the height of the main negative charge region and the charge intensity of the lower positive charge region are suitable.

  18. Analysis of Transient Phenomena Due to a Direct Lightning Strike on a Wind Energy System

    Directory of Open Access Journals (Sweden)

    João P. S. Catalão

    2012-07-01

    Full Text Available This paper is concerned with the protection of wind energy systems against the direct effects of lightning. As wind power generation undergoes rapid growth, lightning damages involving wind turbines have come to be regarded as a serious problem. Nevertheless, very few studies exist yet in Portugal regarding lightning protection of wind energy systems using numerical codes. A new case study is presented in this paper, based on a wind turbine with an interconnecting transformer, for the analysis of transient phenomena due to a direct lightning strike to the blade. Comprehensive simulation results are provided by using models of the Restructured Version of the Electro-Magnetic Transients Program (EMTP, and conclusions are duly drawn.

  19. Measuring Method for Lightning Channel Temperature

    Science.gov (United States)

    Li, X.; Zhang, J.; Chen, L.; Xue, Q.; Zhu, R.

    2016-01-01

    In this paper, we demonstrate the temperature of lightning channel utilizing the theory of lightning spectra and the model of local thermodynamic equilibrium (LTE). The impulse current generator platform (ICGS) was used to simulate the lightning discharge channel, and the spectral energy of infrared spectroscopy (930 nm) and the visible spectroscopy (648.2 nm) of the simulated lightning has been calculated. Results indicate that the peaks of luminous intensity of both infrared and visible spectra increase with the lightning current intensity in range of 5–50 kA. Based on the results, the temperature of the lightning channel is derived to be 6140.8–10424 K. Moreover, the temperature of the channel is approximately exponential to the lightning current intensity, which shows good agreement with that of the natural lightning cases. PMID:27665937

  20. Measuring Method for Lightning Channel Temperature

    Science.gov (United States)

    Li, X.; Zhang, J.; Chen, L.; Xue, Q.; Zhu, R.

    2016-09-01

    In this paper, we demonstrate the temperature of lightning channel utilizing the theory of lightning spectra and the model of local thermodynamic equilibrium (LTE). The impulse current generator platform (ICGS) was used to simulate the lightning discharge channel, and the spectral energy of infrared spectroscopy (930 nm) and the visible spectroscopy (648.2 nm) of the simulated lightning has been calculated. Results indicate that the peaks of luminous intensity of both infrared and visible spectra increase with the lightning current intensity in range of 5-50 kA. Based on the results, the temperature of the lightning channel is derived to be 6140.8-10424 K. Moreover, the temperature of the channel is approximately exponential to the lightning current intensity, which shows good agreement with that of the natural lightning cases.

  1. Lightning NOx and Impacts on Air Quality

    Science.gov (United States)

    Murray, Lee T.

    2016-01-01

    Lightning generates relatively large but uncertain quantities of nitrogen oxides, critical precursors for ozone and hydroxyl radical (OH), the primary tropospheric oxidants. Lightning nitrogen oxide strongly influences background ozone and OH due to high ozone production efficiencies in the free troposphere, effecting small but non-negligible contributions to surface pollutant concentrations. Lightning globally contributes 3-4 ppbv of simulated annual-mean policy-relevant background (PRB) surface ozone, comprised of local, regional, and hemispheric components, and up to 18 ppbv during individual events. Feedbacks via methane may counter some of these effects on decadal time scales. Lightning contributes approximately 1 percent to annual-mean surface particulate matter, as a direct precursor and by promoting faster oxidation of other precursors. Lightning also ignites wildfires and contributes to nitrogen deposition. Urban pollution influences lightning itself, with implications for regional lightning-nitrogen oxide production and feedbacks on downwind surface pollution. How lightning emissions will change in a warming world remains uncertain.

  2. Measuring Method for Lightning Channel Temperature.

    Science.gov (United States)

    Li, X; Zhang, J; Chen, L; Xue, Q; Zhu, R

    2016-09-26

    In this paper, we demonstrate the temperature of lightning channel utilizing the theory of lightning spectra and the model of local thermodynamic equilibrium (LTE). The impulse current generator platform (ICGS) was used to simulate the lightning discharge channel, and the spectral energy of infrared spectroscopy (930 nm) and the visible spectroscopy (648.2 nm) of the simulated lightning has been calculated. Results indicate that the peaks of luminous intensity of both infrared and visible spectra increase with the lightning current intensity in range of 5-50 kA. Based on the results, the temperature of the lightning channel is derived to be 6140.8-10424 K. Moreover, the temperature of the channel is approximately exponential to the lightning current intensity, which shows good agreement with that of the natural lightning cases.

  3. Multivariate Statistical Inference of Lightning Occurrence, and Using Lightning Observations

    Science.gov (United States)

    Boccippio, Dennis

    2004-01-01

    Two classes of multivariate statistical inference using TRMM Lightning Imaging Sensor, Precipitation Radar, and Microwave Imager observation are studied, using nonlinear classification neural networks as inferential tools. The very large and globally representative data sample provided by TRMM allows both training and validation (without overfitting) of neural networks with many degrees of freedom. In the first study, the flashing / or flashing condition of storm complexes is diagnosed using radar, passive microwave and/or environmental observations as neural network inputs. The diagnostic skill of these simple lightning/no-lightning classifiers can be quite high, over land (above 80% Probability of Detection; below 20% False Alarm Rate). In the second, passive microwave and lightning observations are used to diagnose radar reflectivity vertical structure. A priori diagnosis of hydrometeor vertical structure is highly important for improved rainfall retrieval from either orbital radars (e.g., the future Global Precipitation Mission "mothership") or radiometers (e.g., operational SSM/I and future Global Precipitation Mission passive microwave constellation platforms), we explore the incremental benefit to such diagnosis provided by lightning observations.

  4. Infrasonic Observations from Triggered Lightning

    Science.gov (United States)

    Arechiga, R. O.; Johnson, J. B.; Edens, H. E.; Rison, W.; Thomas, R. J.; Eack, K.; Eastvedt, E. M.

    2009-12-01

    We measured acoustic signals during both triggered and natural lightning. A comparative analysis of simultaneous data from the Lightning Mapping Array (LMA), acoustic measurements and digital high-speed photography operating in the same area was made. Acoustic emissions, providing quantitative estimates of acoustic power and spectral content, will complement coincident investigations, such as X-ray emissions. Most cloud-to-ground lightning flashes lower negative charge to ground, but flashes that lower positive charge to ground are often unusually destructive and are less understood. The New Mexico Tech Lightning Mapping Array (LMA) locates the sources of impulsive RF radiation produced by lightning flashes in three spatial dimensions and time, operating in the 60 - 66 MHz television band. However, positive breakdown is rarely detected by the LMA and positive leader channels are outlined only by recoil events. Positive cloud-to-ground (CG) channels are usually not mapped (or partially mapped because they may have recoil events). Acoustic and electric field instruments are a good complement to the LMA, since they can detect both negative and positive leaders. An array of five stations was deployed during the Summer of 2009 (July 20 to August 13) in the Magdalena mountains of New Mexico, to monitor infrasound (below 20 Hz) and audio range sources due to natural and triggered lightning. The stations were located at close (57 m), medium (303 and 537 m) and far (1403 and 2556 m) distances surrounding the triggering site. Each station consisted of five sensors, one infrasonic and one in the audio range at the center, and three infrasonic in a triangular configuration. This research will provide a more complete picture, and provide further insight into the nature of lightning.

  5. Diagnosis of a tank fire due to a lightning strike in a petroleum facility

    Energy Technology Data Exchange (ETDEWEB)

    Torres, Horacio; Rondon, Daniel; Gonzalez, Diego; Gallego, Luis; Montana, Johny; Herrera, Javier; Perz, Ernesto; Vargas, Mauricio; Quintana, Carlos; Younes, Camilo; Salgado, Milton; Gonzalez, Jose [Universidad Nacional de Colombia, Bogota (Colombia)]. E-mail: paas@paas.unal.edu.co

    2001-07-01

    The aim of this paper is to present ana analysis of the cause of fire in a crude storage tank, which was strike by a lightning discharge in a Petroleum facility located in Colombia, South America. In order to avoid accidents in futures, necessary modifications for the improvement of lightning protection system in crude storage tanks are suggested. Additionally, as pertinent description of the electrical pointy of view, diagnosis and recommendations are presented. (author)

  6. Experimental generation of volcanic lightning

    Science.gov (United States)

    Cimarelli, Corrado; Alatorre-Ibargüengoitia, Miguel; Kueppers, Ulrich; Scheu, Bettina; Dingwell, Donald B.

    2014-05-01

    Ash-rich volcanic plumes that are responsible for injecting large quantities of aerosols into the atmosphere are often associated with intense electrical activity. Direct measurement of the electric potential at the crater, where the electric activity in the volcanic plume is first observed, is severely impeded, limiting progress in its investigation. We have achieved volcanic lightning in the laboratory during rapid decompression experiments of gas-particle mixtures under controlled conditions. Upon decompression (from ~100 bar argon pressure to atmospheric pressure), loose particles are vertically accelerated and ejected through a nozzle of 2.8 cm diameter into a large tank filled with air at atmospheric conditions. Because of their impulsive character, our experiments most closely represent the conditions encountered in the gas-thrust region of the plume, when ash is first ejected from the crater. We used sieved natural ash with different grain sizes from Popocatépetl (Mexico), Eyjafjallajökull (Iceland), and Soufrière Hills (Montserrat) volcanoes, as well as micrometric glass beads to constrain the influence of material properties on lightning. We monitored the dynamics of the particle-laden jets with a high-speed camera and the pressure and electric potential at the nozzle using a pressure transducer and two copper ring antennas connected to a high-impedance data acquisition system, respectively. We find that lightning is controlled by the dynamics of the particle-laden jet and by the abundance of fine particles. Two main conditions are required to generate lightning: 1) self-electrification of the particles and 2) clustering of the particles driven by the jet fluid dynamics. The relative movement of clusters of charged particles within the plume generates the gradient in electrical potential, which is necessary for lightning. In this manner it is the gas-particle dynamics together with the evolving particle-density distribution within different regions of

  7. Tropic lightning: myth or menace?

    Science.gov (United States)

    McCarthy, John

    2014-11-01

    Lightning is one of the leading causes of death related to environmental disaster. Of all lightning fatalities documented between 2006 and 2012, leisure activities contributed the largest proportion of deaths, with water-associated, sports, and camping being the most common. Despite the prevalence of these activities throughout the islands, Hawai'i has had zero documented lightning fatalities since weather data tracking was initiated in 1959. There is a common misconception that lightning does not strike the ground in Hawai'i. This myth may contribute to a potentially dangerous false sense of security, and recognition of warning signs and risk factor modification remain the most important prevention strategies. Lightning damage occurs on a spectrum, from minor burns to multi-organ dysfunction. After injury, initial treatment should focus on "reverse triage" and immediate cardiopulmonary resuscitation when indicated, followed by transfer to a healthcare facility. Definitive treatment entails monitoring and management of potential sequelae, to include cardiovascular, neurologic, dermatologic, ophthalmologic, audiovestibular, and psychiatric complications.

  8. Positive lightning and severe weather

    Science.gov (United States)

    Price, C.; Murphy, B.

    2003-04-01

    In recent years researchers have noticed that severe weather (tornados, hail and damaging winds) are closely related to the amount of positive lightning occurring in thunderstorms. On 4 July 1999, a severe derecho (wind storm) caused extensive damage to forested regions along the United States/Canada border, west of Lake Superior. There were 665,000 acres of forest destroyed in the Boundary Waters Canoe Area Wilderness (BWCAW) in Minnesota and Quetico Provincial Park in Canada, with approximately 12.5 million trees blown down. This storm resulted in additional severe weather before and after the occurrence of the derecho, with continuous cloud-to-ground (CG) lightning occurring for more than 34 hours during its path across North America. At the time of the derecho the percentage of positive cloud-to-ground (+CG) lightning measured by the Canadian Lightning Detection Network (CLDN) was greater than 70% for more than three hours, with peak values reaching 97% positive CG lightning. Such high ratios of +CG are rare, and may be useful indicators for short-term forecasts of severe weather.

  9. Fire Environment Mechanism of Lightning Fire for Daxing an Mountains

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Lightning fire is one of natural fires; its mechanism is very complex and difficult to control. Daxing'an Mountain is the main region that lightning fires occur in China. Research on lightning fires indicates that special fuel, dry-storm weather and high altitude form the lightning fire environment. Lightning fires have close relation with lights. When lightning occurs, especially dry-lightning which brings little precipitation with surface temperature growing and fuel dehydrating, these often lead to l...

  10. THE EFFECT OF LIGHTNING ON HIGH VOLTAGE ELECTRICAL SUBSTATIONS’ LOW VOLTAGE SYSTEMS

    Directory of Open Access Journals (Sweden)

    M. I. Fursanov

    2016-01-01

    Full Text Available The article presents the results of studies of the effects of lightning on low voltage systems of high voltage electrical substations with outdoor switchgears of 110 kV. The topicality of research is associated with a wide spreading of such substations as well as with a high reliability requirements of their work and, also, with their widespread distribution and high probability of lightning strikes to the substation or around it. The highest probable and the most dangerous effects of lightning on low voltage systems of a substation are determined on the basis of critical review and special literature analysis and, also, of systematization of practical information that had been collected during the survey of operating substations. Adequate physical models were developed for the list of hazardous effects based on physical processes of lightning. A model of each effect was studied on the basis of the sensitivity theory. The accuracy and adequacy of the models were verified by means of comparison of calculation results for the models under investigation with the results of calculations fulfilled in accordance with specialized programs, as well as from practical or theoretical data obtained by other authors. The factors that had been included in the models were studied and were defined in accordance with their nature (natural or artificial, the range of possible values in a substation was determined; the coefficients of elasticity were calculated. The obtained results enable to ascertain the contribution of the factor in the effect of lightning and the ability to control the factor. The relationship between the factors and the effects of lightning are shown as graphs. For practical application the information, obtained as the result of the research, was organized in the form of checklists that can be applied when collecting baseline information to develop the lightning protection of the substation, to examine the existing lightning protection, to

  11. A Study on EMTP-Analysis Model for Switch-Board SPD with Gap and Propagation Characteristics of Lightning Surge on Simple Indoor Distribution Line

    Science.gov (United States)

    Sakamoto, Yoshiki; Miyazaki, Teru; Okabe, Shigemitsu

    The numbers of damages of home electric appliances due to lightning surges have recently increased. Installing Surge Protective Devices (SPDs) for indoor distribution line is one of countermeasures against the damages, and is also spreading after an amendment of the regulation on indoor wires in 2005. Past studies have showed that the SPDs installed on the switchboard are effective for protecting all the equipment supplied by indoor distribution lines against lightning strokes. However, it is difficult to evaluate the protective effects of the SPDs against lightning strikes when considering complex indoor wires in houses. Thus, a high-precision analysis method is required to clarify the lightning performance of the SPDs for interior wiring. In this research, experiments were conducted to grasp the protective effects of the SPDs installed on a switchboard against lightning surges invading into a house, and an analysis model by the EMTP was proposed. The calculated results relatively agreed with the experimental results.

  12. Lightning current parameters according to IEC 62305. Background, experience and outlook; Blitzstromparameter nach IEC 62305. Hintergrund, Erfahrung und Ausblick

    Energy Technology Data Exchange (ETDEWEB)

    Heidler, Fridolin [Universitaet der Bundeswehr Muenchen, Neubiberg (Germany). Inst. fuer Elektrische Energieversorgung

    2009-01-15

    Lightning protection measures are specified in the international standard series IEC 62305, which were integrated in European and German standards immediately upon publication in early 2006. The German version is the DIN EN 62 305 (VDE 0185-305). Investigations have shown that lightning currents present the biggest hazard. It is therefore the main danger at which all protective measures of the IEC 62305 standard series are aimed. The lightning current parameters to which the standards refer are based on long-term measurements carried out by Prof. Karl Berger on two telecommunication towers on San Salvatore mountain, Switzerland. (orig.)

  13. Modeling Lightning Impact Thermo-Mechanical Damage on Composite Materials

    Science.gov (United States)

    Muñoz, Raúl; Delgado, Sofía; González, Carlos; López-Romano, Bernardo; Wang, De-Yi; LLorca, Javier

    2014-02-01

    Carbon fiber-reinforced polymers, used in primary structures for aircraft due to an excellent strength-to-weight ratio when compared with conventional aluminium alloy counterparts, may nowadays be considered as mature structural materials. Their use has been extended in recent decades, with several aircraft manufacturers delivering fuselages entirely manufactured with carbon composites and using advanced processing technologies. However, one of the main drawbacks of using such composites entails their poor electrical conductivity when compared with aluminium alloy competitors that leads to lightning strikes being considered a significant threat during the service life of the aircraft. Traditionally, this problem was overcome with the use of a protective copper/bronze mesh that added additional weight and reduced the effectiveness of use of the material. Moreover, this traditional sizing method is based on vast experimental campaigns carried out by subjecting composite panels to simulated lightning strike events. While this method has proven its validity, and is necessary for certification of the structure, it may be optimized with the aid provided by physically based numerical models. This paper presents a model based on the finite element method that includes the sources of damage observed in a lightning strike, such as thermal damage caused by Joule overheating and electromagnetic/acoustic pressures induced by the arc around the attachment points. The results of the model are compared with lightning strike experiments carried out in a carbon woven composite.

  14. Lightning and Life on Exoplanets

    Science.gov (United States)

    Rimmer, Paul; Ardaseva, Aleksandra; Hodosan, Gabriella; Helling, Christiane

    2016-07-01

    Miller and Urey performed a ground-breaking experiment, in which they discovered that electric discharges through a low redox ratio gas of methane, ammonia, water vapor and hydrogen produced a variety of amino acids, the building blocks of proteins. Since this experiment, there has been significant interest on the connection between lightning chemistry and the origin of life. Investigation into the atmosphere of the Early Earth has generated a serious challenge for this project, as it has been determined both that Earth's early atmosphere was likely dominated by carbon dioxide and molecular nitrogen with only small amounts of hydrogen, having a very high redox ratio, and that discharges in gases with high redox ratios fail to yield more than trace amounts of biologically relevant products. This challenge has motivated several origin of life researchers to abandon lightning chemistry, and to concentrate on other pathways for prebiotic synthesis. The discovery of over 2000 exoplanets includes a handful of rocky planets within the habitable zones around their host stars. These planets can be viewed as remote laboratories in which efficient lightning driven prebiotic synthesis may take place. This is because many of these rocky exoplanets, called super-Earths, have masses significantly greater than that of Earth. This higher mass would allow them to more retain greater amounts hydrogen within their atmosphere, reducing the redox ratio. Discharges in super-Earth atmospheres can therefore result in a significant yield of amino acids. In this talk, I will discuss new work on what lightning might look like on exoplanets, and on lightning driven chemistry on super-Earths. Using a chemical kinetics model for a super-Earth atmosphere with smaller redox ratios, I will show that in the presence of lightning, the production of the amino acid glycine is enhanced up to a certain point, but with very low redox ratios, the production of glycine is again inhibited. I will conclude

  15. The Anthropogenic/Lightning Effects Around Houston: The Houston Environmental Aerosol Thunderstorm (HEAT) Project - 2005

    Science.gov (United States)

    Orville, R. E.

    2004-12-01

    A major field program will occur in summer 2005 to determine the sources and causes for the enhanced cloud-to-ground lightning over Houston, Texas. This program will be in association with simultaneous experiments supported by the Environmental Protection Agency (EPA) and the Texas Commission on Environmental Quality (TCEQ), formally the Texas Natural Resource Conservation Commission (TNRCC). Recent studies covering the period 1989-2002 document a 60 percent increase of cloud-to-ground lightning in the Houston area as compared to surrounding background values, which is second in flash density only to the Tampa Bay, Florida area. We suggest that the elevated flash densities could result from several factors, including 1) the convergence due to the urban heat island effect and complex sea breeze (thermal hypothesis), and 2) the increasing levels of air pollution from anthropogenic sources producing numerous small cloud droplets and thereby suppressing mean droplet size (aerosol hypothesis). The latter effect would enable more cloud water to reach the mixed phase region where it is involved in the formation of precipitation and the separation of electric charge, leading to an enhancement of lightning. The primary goals of HEAT are to examine the effects of (1) pollution, (2) the urban heat island, and (3) the complex coastline on storms and lightning characteristics in the Houston area. The transport of air pollutants by Houston thunderstorms will be investigated. In particular, the relative amounts of lightning-produced and convectively transported NOx into the upper troposphere will be determined, and a comparison of the different NOx sources in the urban area of Houston will be developed. The HEAT project is based on the observation that there is an enhancement in cloud-to-ground (CG) lightning. Total lightning (intracloud (IC) and CG) will be measured using a lightning mapping system (LDAR II) to observe if there is an enhancement in intracloud lightning as well.

  16. Artificially triggered lightning and its characteristic discharge parameters in two severe thunderstorms

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The lightning-induced-damages in the mid-latitude regions are usually caused during severe thunder-storms. But the discharge parameters of natural lightning are difficult to be measured. Five lightning flashes have been artificially triggered with the rocket-wire technique during the passage of two severe thunderstorms. The discharge current and close electric field of return stroke in artificially triggered lightning have been obtained in microsecond time resolution by using current measuring systems and electric field change sensors. The results show that the five triggered lightning flashes include 1 to 10 return strokes, and the average return stroke current is 11.9 kA with a maximum of 21.0 kA and a mini-mum of 6.6 kA, similar to the subsequent return strokes in natural lightning. The half peak width of the current waveform is 39 μs, which is much larger than the usual result. The peak current of stroke Ip (kA) and the neutralized charge Q(C) has a relationship of Ip = 18.5Q0.65. The radiation field of return stroke is 5.9 kV·m-1 and 0.39 kV·m-1 at 60 m and 550 m, respectively. The radiation field decreases as r -1.119 with increase of horizontal distance r from the discharge channel. Based on the well-accepted transmission line model, the speed of return stroke is estimated to be about 1.4×108 m·s-1, with a variation range of (1.1―1.6)×108 m·s-1. Because of the similarities of the triggered lightning and natural lightning, the results in this article can be used in the protection design of natural lightning.

  17. Upgraded FAA Airfield Capacity Model Compiled from the Following Reports: FAA-RD-76-128 and FAA-EM-81-1-VOL-1

    Science.gov (United States)

    1981-05-01

    Arrival-Arrival Separations: DLTAIJ: 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 103 ** FAA CAPACITY MODEL - REVISED JANUARY, 1980 ** "t AIRFIELD HOURLY CAPACITY MODELO ...OLTEI:N1IIi Alifl1AL D1LAY rOi, z.rIrf XIJAL DEIIAjiD? 110- D’O YOU 1’ ISI ( TO FILIWRPNl ANOTHER1 CALCIAIVIO:1? 110! rIGU~n 6-3 (Cont.) 178 CHAPTER 7 - ON

  18. Lightning hazard reduction at wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Kithil, R. [National Lightning Safety Institute, Louisville, CO (United States)

    1997-12-31

    The USA wind farm industry (WFI) largely is centered in low-lightning areas of the State of California. While some evidence of lightning incidents is reported here, the problem is not regarded as serious by most participants. The USA WFI now is moving eastward, into higher areas of lightning activity. The European WFI has had many years experience with lightning problems. One 1995 German study estimated that 80% of wind turbine insurance claims paid for damage compensation were caused by lightning strikes. The European and USA WFI have not adopted site criteria, design fundamentals, or certification techniques aimed at lightning safety. Sufficient evidence about lightning at wind farms is available to confirm that serious potential problems exist.

  19. A Study of Lightning Protection Systems

    Science.gov (United States)

    1981-10-01

    cording systems extended from agnetic field systems from 1 ic and magnetic fields, the about 0.3 microsecond, ly at two Florida stations th the result...voltages can occur, it is often necessary to utilize one or more voltage limiting devices to hold or clamp these transients to a harmless level...channels triggered by Apollo 12 at an altitude of about 2 km struck the high-pressure gas facility within 30 m of the base of the 160 m launch umbilical

  20. 14 CFR 420.71 - Lightning protection.

    Science.gov (United States)

    2010-01-01

    ... metallic power, communication, and instrumentation lines entering an explosive hazard facility. (3... tests, including any action taken to correct deficiencies noted. (b) Electrical power lines. A licensee shall ensure that electric power lines at its launch site meet the following requirements: (1)...

  1. Probability, consequences, and mitigation for lightning strikes of Hanford high level waste tanks

    Energy Technology Data Exchange (ETDEWEB)

    Zach, J.J.

    1996-06-05

    The purpose of this report is to summarize selected lightning issues concerning the Hanford Waste Tanks. These issues include the probability of a lightning discharge striking the area immediately adjacent to a tank including a riser, the consequences of significant energy deposition from a lightning strike in a tank, and mitigating actions that have been or are being taken. The major conclusion of this report is that the probability of a lightning strike deposition sufficient energy in a tank to cause an effect on employees or the public is unlikely;but there are insufficient, quantitative data on the tanks and waste to prove that. Protection, such as grounding of risers and air terminals on existing light poles, is recommended.

  2. Probability, consequences, and mitigation for lightning strikes to Hanford site high-level waste tanks

    Energy Technology Data Exchange (ETDEWEB)

    Zach, J.J.

    1996-08-01

    The purpose of this report is to summarize selected lightning issues concerning the Hanford Waste Tanks. These issues include the probability of lightning discharge striking the area immediately adjacent to a tank including a riser, the consequences of significant energy deposition from a lightning strike in a tank, and mitigating actions that have been or are being taken. The major conclusion of this report is that the probability of a lightning strike depositing sufficient energy in a tank to cause an effect on employees or the public is unlikely;but there are insufficient, quantitative data on the tanks and waste to prove that. Protection, such as grounding of risers and air terminals on existing light poles, is recommended.

  3. Simulation of Lightning Overvoltage Distribution on Stator Windings of Wind Turbine Generators

    Institute of Scientific and Technical Information of China (English)

    LIU Rong; LIU Xue-zhong; WANG Ying; LI Dan-dan

    2011-01-01

    This paper analyzes lightning surge on the stator windings of wind turbine generators. The path of lightning in the wind turbines was analyzed. An equivalent circuit model for megawatt direct-driven wind turbine system was developed, in which high-frequency distributed parameters of the blade conducts, tower, power cables and stator windings of generator were calculated based on finite element method, and the models of converter, grounding, loads, surge protection devices and power grid were established. The voltage distribution along stator windings, when struck by lightning with 10/350 ~ts wave form and different amplitude current between 50 kA and 200 kA, was simulated u- sing electro-magnetic transient analysis method. The simulated results show that the highest coil-to-core voltage peak appears on the last coil or near the neutral of stator windings, and the voltage distribution along the windings is non- uniform initially. The voltage drops of each coil fall from first to last coil, and the highest voltage drop appears on the first coil. The insulation damage may occur on the windings under lightning overvoltage. The surge arresters can re- strain the lightning surge in effect and protect the insulation. The coil-to-core voltage in the end of windings is nearly 19.5 kV under the 200 kA lightning current without surge arresters on the terminal of generator, but is only 2.7 kV with arresters.

  4. A Methodology to Reduce the Computational Effort in the Evaluation of the Lightning Performance of Distribution Networks

    Directory of Open Access Journals (Sweden)

    Ilaria Bendato

    2016-11-01

    Full Text Available The estimation of the lightning performance of a power distribution network is of great importance to design its protection system against lightning. An accurate evaluation of the number of lightning events that can create dangerous overvoltages requires a huge computational effort, as it implies the adoption of a Monte Carlo procedure. Such a procedure consists of generating many different random lightning events and calculating the corresponding overvoltages. The paper proposes a methodology to deal with the problem in two computationally efficient ways: (i finding out the minimum number of Monte Carlo runs that lead to reliable results; and (ii setting up a procedure that bypasses the lightning field-to-line coupling problem for each Monte Carlo run. The proposed approach is shown to provide results consistent with existing approaches while exhibiting superior Central Processing Unit (CPU time performances.

  5. First Annual FAA General Aviation Forecast Conference Proceedings

    Science.gov (United States)

    1991-03-01

    pilot’s perspective. I have a 30-year background as an executive in communications, principally in television , but I am also an aircraft owner and have...contrasting this with the business I came from -- television , which is gauged and governed by the TV rating business, which includes overnight ratings. We...ago following the Ceritos, California midair collision between a general aviation aircraft and a Mexicana airliner, the FAA released a study calling for

  6. A Conjecture Concerning Ball Lightning

    CERN Document Server

    Sturrock, P A

    2016-01-01

    There is at present no theory that can explain the curious properties of ball lightning. This suggests that we may not be using the most appropriate concepts. The concept of a 'parallel space' may point the way to a valid theory.

  7. Jovian Lightning and Moonlit Clouds

    Science.gov (United States)

    1997-01-01

    Jovian lightning and moonlit clouds. These two images, taken 75 minutes apart, show lightning storms on the night side of Jupiter along with clouds dimly lit by moonlight from Io, Jupiter's closest moon. The images were taken in visible light and are displayed in shades of red. The images used an exposure time of about one minute, and were taken when the spacecraft was on the opposite side of Jupiter from the Earth and Sun. Bright storms are present at two latitudes in the left image, and at three latitudes in the right image. Each storm was made visible by multiple lightning strikes during the exposure. Other Galileo images were deliberately scanned from east to west in order to separate individual flashes. The images show that Jovian and terrestrial lightning storms have similar flash rates, but that Jovian lightning strikes are a few orders of magnitude brighter in visible light.The moonlight from Io allows the lightning storms to be correlated with visible cloud features. The latitude bands where the storms are seen seem to coincide with the 'disturbed regions' in daylight images, where short-lived chaotic motions push clouds to high altitudes, much like thunderstorms on Earth. The storms in these images are roughly one to two thousand kilometers across, while individual flashes appear hundreds of kilometer across. The lightning probably originates from the deep water cloud layer and illuminates a large region of the visible ammonia cloud layer from 100 kilometers below it.There are several small light and dark patches that are artifacts of data compression. North is at the top of the picture. The images span approximately 50 degrees in latitude and longitude. The lower edges of the images are aligned with the equator. The images were taken on October 5th and 6th, 1997 at a range of 6.6 million kilometers by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft.The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office

  8. The Colorado Lightning Mapping Array

    Science.gov (United States)

    Rison, W.; Krehbiel, P. R.; Thomas, R. J.; Rodeheffer, D.; Fuchs, B.

    2012-12-01

    A fifteen station Lightning Mapping Array (LMA) was installed in northern Colorado in the spring of 2012. While the driving force for the array was to produce 3-dimensional lightning data to support the Deep Convective Clouds and Chemistry (DC3) Experiment (Barth, this conference), data from the array are being used for several other projects. These include: electrification studies in conjunction with the CSU CHILL radar (Lang et al, this conference); observations of the parent lightning discharges of sprites (Lyons et al, this conference); trying to detect upward discharges triggered by wind turbines, characterizing conditions in which aircraft flying through clouds produce discharges which can be detected by the LMA, and other opportunities, such as observations of lightning in pyrocumulus clouds produced by the High Park Fire west of Fort Collins, CO. All the COLMA stations are solar-powered, and use broadband cellular modems for data communications. This makes the stations completely self-contained and autonomous, allowing a station to be installed anywhere a cellular signal is available. Because most of the stations were installed well away from anthropogenic noise sources, the COLMA is very sensitive. This is evidenced by the numerous plane tracks detected in its the vicinity. The diameter, D, of the COLMA is about 100 km, significantly larger than other LMAs. Because the error in the radial distance r is proportional to (r/D)2, and the error in the altitude z is proportional to (z/D)2, the larger array diameter greatly expands the usable range of the COLMA. The COLMA is able to detect and characterize lighting flashes to a distance of about 350 km from the array center. In addition to a web-based display (lightning.nmt.edu/colma), geo-referenced images are produced and updated at one-minute intervals. These geo-referenced images can be used to overlay the real-time lightning data on Google Earth and other mapping software. These displays were used by the DC3

  9. On the Relationship between Observed NLDN Lightning ...

    Science.gov (United States)

    Lightning-produced nitrogen oxides (NOX=NO+NO2) in the middle and upper troposphere play an essential role in the production of ozone (O3) and influence the oxidizing capacity of the troposphere. Despite much effort in both observing and modeling lightning NOX during the past decade, considerable uncertainties still exist with the quantification of lightning NOX production and distribution in the troposphere. It is even more challenging for regional chemistry and transport models to accurately parameterize lightning NOX production and distribution in time and space. The Community Multiscale Air Quality Model (CMAQ) parameterizes the lightning NO emissions using local scaling factors adjusted by the convective precipitation rate that is predicted by the upstream meteorological model; the adjustment is based on the observed lightning strikes from the National Lightning Detection Network (NLDN). For this parameterization to be valid, the existence of an a priori reasonable relationship between the observed lightning strikes and the modeled convective precipitation rates is needed. In this study, we will present an analysis leveraged on the observed NLDN lightning strikes and CMAQ model simulations over the continental United States for a time period spanning over a decade. Based on the analysis, new parameterization scheme for lightning NOX will be proposed and the results will be evaluated. The proposed scheme will be beneficial to modeling exercises where the obs

  10. Where are the lightning hotspots on Earth?

    Science.gov (United States)

    Albrecht, R. I.; Goodman, S. J.; Buechler, D. E.; Blakeslee, R. J.; Christian, H. J., Jr.

    2015-12-01

    The first lightning observations from space date from the early 1960s and more than a dozen spacecraft orbiting the Earth have flown instruments that recorded lightning signals from thunderstorms over the past 45 years. In this respect, the Tropical Rainfall Measuring Mission (TRMM) Lightning Imaging Sensor (LIS), having just completed its mission (1997-2015), provides the longest and best total (intracloud and cloud-to-ground) lightning data base over the tropics.We present a 16 year (1998-2013) reprocessed data set to create very high resolution (0.1°) TRMM LIS total lightning climatology. This detailed very high resolution climatology is used to identify the Earth's lightning hotspots and other regional features. Earlier studies located the lightning hotspot within the Congo Basin in Africa, but our very high resolution lightning climatology found that the highest lightning flash rate on Earth actually occurs in Venezuela over Lake Maracaibo, with a distinct maximum during the night. The higher resolution dataset clearly shows that similar phenomenon also occurs over other inland lakes with similar conditions, i.e., locally forced convergent flow over a warm lake surface which drives deep nocturnal convection. Although Africa does not have the top lightning hotspot, it comes in a close second and it is the continent with the highest number of lightning hotspots, followed by Asia, South America, North America, and Oceania. We also present climatological maps for local hour and month of lightning maxima, along with a ranking of the highest five hundred lightning maxima, focusing discussion on each continent's 10 highest lightning maxima. Most of the highest continental maxima are located near major mountain ranges, revealing the importance of local topography in thunderstorm development. These results are especially relevant in anticipation of the upcoming availability of continuous total lightning observations from the Geostationary Lightning Mapping (GLM

  11. The Acyl-CoA synthetases encoded within FAA1 and FAA4 in Saccharomyces cerevisiae function as components of the fatty acid transport system linking import, activation, and intracellular Utilization

    DEFF Research Database (Denmark)

    Færgeman, Nils J.; Black, P N; Zhao, X D

    2001-01-01

    Exogenous long-chain fatty acids are activated to coenzyme A derivatives prior to metabolic utilization. In the yeast Saccharomyces cerevisiae, the activation of these compounds prior to metabolic utilization proceeds through the fatty acyl-CoA synthetases Faa1p and Faa4p. Faa1p or Faa4p are esse...

  12. Modelling of lightning streamer formation and propagation in wind turbine blades

    DEFF Research Database (Denmark)

    Candela Garolera, Anna; Holbøll, Joachim; Madsen, Søren Find

    2013-01-01

    The positioning of lightning air terminations along a wind turbine blade is a complex issue to consider when designing the lightning protection of wind turbine blades. According to the IEC 61400-24 on lightning protection of wind turbines, the interception efficiency depends on the effectiveness ...... models can involve a high level of detail and therefore be used in the detailed positioning of air terminations in blades equipped with conductive elements such as carbon fiber or electrical monitoring systems (load, temperature, etc.)....... setups. Furthermore, the tests may need to be repeated when a new conducting element is included in the blade with unpredictable effects for the lightning protection system. Numerical methods to determine the areas of a structure more likely to be struck by lightning have proved to be a useful tool....... The present paper presents a method to investigate the origin and propagation of streamers from different conductive elements of the blade when exposed to a high electric field. The calculations are performed using dynamic simulations with the finite element method, and the results have been correlated...

  13. Geological Effects on Lightning Strike Distributions

    KAUST Repository

    Berdahl, J. Scott

    2016-05-16

    Recent advances in lightning detection networks allow for detailed mapping of lightning flash locations. Longstanding rumors of geological influence on cloud-to-ground (CG) lightning distribution and recent commercial claims based on such influence can now be tested empirically. If present, such influence could represent a new, cheap and efficient geophysical tool with applications in mineral, hydrothermal and oil exploration, regional geological mapping, and infrastructure planning. This project applies statistical analysis to lightning data collected by the United States National Lightning Detection Network from 2006 through 2015 in order to assess whether the huge range in electrical conductivities of geological materials plays a role in the spatial distribution of CG lightning. CG flash densities are mapped for twelve areas in the contiguous United States and compared to elevation and geology, as well as to the locations of faults, railroads and tall towers including wind turbines. Overall spatial randomness is assessed, along with spatial correlation of attributes. Negative and positive polarity lightning are considered separately and together. Topography and tower locations show a strong influence on CG distribution patterns. Geology, faults and railroads do not. This suggests that ground conductivity is not an important factor in determining lightning strike location on scales larger than current flash location accuracies, which are generally several hundred meters. Once a lightning channel is established, however, ground properties at the contact point may play a role in determining properties of the subsequent stroke.

  14. Overview of Saturn lightning observations

    CERN Document Server

    Fischer, G; Kurth, W S; Gurnett, D A; Zarka, P; Barry, T; Delcroix, M; Go, C; Peach, D; Vandebergh, R; Wesley, A

    2011-01-01

    The lightning activity in Saturn's atmosphere has been monitored by Cassini for more than six years. The continuous observations of the radio signatures called SEDs (Saturn Electrostatic Discharges) combine favorably with imaging observations of related cloud features as well as direct observations of flash-illuminated cloud tops. The Cassini RPWS (Radio and Plasma Wave Science) instrument and ISS (Imaging Science Subsystem) in orbit around Saturn also received ground-based support: The intense SED radio waves were also detected by the giant UTR-2 radio telescope, and committed amateurs observed SED-related white spots with their backyard optical telescopes. Furthermore, the Cassini VIMS (Visual and Infrared Mapping Spectrometer) and CIRS (Composite Infrared Spectrometer) instruments have provided some information on chemical constituents possibly created by the lightning discharges and transported upward to Saturn's upper atmosphere by vertical convection. In this paper we summarize the main results on Satur...

  15. EMC Practices focused in the mitigation of Lightning Electromagnetic Pulse (LEMP): Earthing and bonding approach of the IEC 62305

    OpenAIRE

    Malagón-Carvajal, Gabriel; Giraldo-Picón, Wilson; Ordoñez-Plata, Gabriel; Chacón, Julio Cesar

    2013-01-01

    This paper presents the results obtained during the parameter identification of electromagnetic compatibility in lightning protection systems. It sets out a number of good engineering practices, aimed at mitigation of disturbances, transient type, created by an electromagnetic pulse, generated during the grounding of lightning. These disturbances are often reflected as overvoltage and / or overcurrent radiated and conducted or also called surges, the latter a strong impact on the operation of...

  16. [Lightning strikes and lightning injuries in prehospital emergency medicine. Relevance, results, and practical implications].

    Science.gov (United States)

    Hinkelbein, J; Spelten, O; Wetsch, W A

    2013-01-01

    Up to 32.2% of patients in a burn center suffer from electrical injuries. Of these patients, 2-4% present with lightning injuries. In Germany, approximately 50 people per year are injured by a lightning strike and 3-7 fatally. Typically, people involved in outdoor activities are endangered and affected. A lightning strike usually produces significantly higher energy doses as compared to those in common electrical injuries. Therefore, injury patterns vary significantly. Especially in high voltage injuries and lightning injuries, internal injuries are of special importance. Mortality ranges between 10 and 30% after a lightning strike. Emergency medical treatment is similar to common electrical injuries. Patients with lightning injuries should be transported to a regional or supraregional trauma center. In 15% of all cases multiple people may be injured. Therefore, it is of outstanding importance to create emergency plans and evacuation plans in good time for mass gatherings endangered by possible lightning.

  17. Lightning-caused fires in Central Spain

    DEFF Research Database (Denmark)

    Nieto Solana, Hector; Aguado, Inmaculada; García, Mariano;

    2012-01-01

    a high occurrence. The research was conducted between May and September, which happens to be the most lightning-fire prone period in Spain, for a three year interval starting in 2002 up to 2004. A time-invariant model for lightning-caused fire occurrence was developed for each region at a spatial...

  18. A model for lightning in littoral areas

    NARCIS (Netherlands)

    Blaj, M.A.; Leferink, Frank Bernardus Johannes

    2009-01-01

    The littoral or coastal areas are different compared to the maritime or continental areas considering lightning. Only the last years some research about these areas has been carried out. The need for a model, regarding the lightning activity in these areas is much needed. And now, with the changes i

  19. When Lightning Strikes a Second Time

    Science.gov (United States)

    Allen, Kent

    2017-01-01

    The chances of lightning striking twice are infinitesimal, at best. What are the odds, in middle age, of being struck with a jarring bolt of figurative lightning, then a few months later being an eyewitness as the same sizzle in the sky jolts a group of students--those decision-makers of tomorrow? The author describes two experiences that proved…

  20. The GOES-R Lightning Mapper Sensor

    Science.gov (United States)

    Buechler, Dennis; Christian, Hugh; Goodman, Steve

    2004-01-01

    The Lightning Mapper Sensor on GOES-R builds on previous measurements of lightning from low earth orbit by the OTD (Optical Transient Detector) and LIS (Lightning Imaging Sensor) sensors. Unlike observations from low earth orbit, the GOES-R platform will allow continuous monitoring of lightning activity over the Continental United States and southern Canada, Central and South America, and portions of the Atlantic and Pacific Oceans. The LMS will detect total (cloud-to-ground and intracloud) lightning at storm scale resolution (approx. 8 km) using a highly sensitive Charge Coupled Device (CCD) detector array. Discrimination between lightning optical transients and a bright sunlit background scene is accomplished by employing spectral, spatial, and temporal filtering along with a background subtraction technique. The result is 24 hour detection capability of total lightning. These total lightning observations can be made available to users within about 20 seconds. Research indicates a number of ways that total lightning observations from LMS could benefit operational activities, including 1) potential increases in lead times and reduced false alarms for severe thunderstorm and tornado Warnings, 2) improved routing of &rail around thunderstorms, 3) support for spacecraft launches and landings, 4) improved ability to monitor tropical cyclone intensity, 5) ability to monitor thunderstorm intensification/weakening during radar outages or where radar coverage is poor, 6) better identification of deep convection for the initialization of numerical prediction models, 7) improved forest fire forecasts, 8) identification of convective initiation, 9) identification of heavy convective snowfall, and 10) enhanced temporal resolution of storm evolution (1 minute) than is available from radar observations. Total lightning data has been used in an operational environment since July 2003 at the Huntsville, Alabama National Weather Service office. Total lightning measurements are

  1. Lightning-caused fires in Central Spain

    DEFF Research Database (Denmark)

    Nieto Solana, Hector; Aguado, Inmaculada; García, Mariano;

    2012-01-01

    Lightning-caused fire occurrence has been modelled for two different Spanish regions, Madrid andAragon, based on meteorological, terrain, and vegetation variables. The model was built on two very contrasting regions, one presenting low number of lightning-caused fires whereas the other presented...... a high occurrence. The research was conducted between May and September, which happens to be the most lightning-fire prone period in Spain, for a three year interval starting in 2002 up to 2004. A time-invariant model for lightning-caused fire occurrence was developed for each region at a spatial...... resolution of 3 km ×3 km. The probabilistic models were based on the logistic regression, aiming to explain the probability of having at least a lightning-fire during the three year period. Results showed that the number of thunderstorms during the three-year period was the most significantvariable...

  2. Lightning injuries in sports and recreation.

    Science.gov (United States)

    Thomson, Eric M; Howard, Thomas M

    2013-01-01

    The powers of lightning have been worshiped and feared by all known human cultures. While the chance of being struck by lightning is statistically very low, that risk becomes much greater in those who frequently work or play outdoors. Over the past 2 yr, there have been nearly 50 lightning-related deaths reported within the United States, with a majority of them associated with outdoor recreational activities. Recent publications primarily have been case studies, review articles, and a discussion of a sixth method of injury. The challenge in reducing lightning-related injuries in organized sports has been addressed well by both the National Athletic Trainers' Association and the National Collegiate Athletic Association in their guidelines on lightning safety. Challenges remain in educating the general population involved in recreational outdoor activities that do not fall under the guidelines of organized sports.

  3. GOES Infrared and Reflectance 0-1 hour Lightning Initiation Indicators: Development and Initial Testing within a Convective Nowcasting System

    Science.gov (United States)

    Mecikalski, J. R.; Harris, R.; MacKenzie, W.; Durkee, P. A.; Iskenderian, H.; Bickmeier, L.; Nielsen, K. E.

    2010-12-01

    Within cumulus cloud fields that develop in conditionally unstable air masses, only a fraction of the cumuli may eventually develop into deep convection. Identifying which of these convective clouds most likely to generate lightning often starts with little more than a qualitative visual satellite analysis. The goal of this study is to identify the observed satellite infrared (IR) signatures associated with growing cumulus clouds prior to the first lightning strike, so-called lightning initiation (LI). This study quantifies the behavior of ten Geostationary Operational Environmental Satellite (GOES-12) IR interest fields in the 1-hour in advance of LI. A total of 172 lightning-producing storms that occurred during the 2009 convective season are manually tracked and studied over four regions: Northern Alabama, Central Oklahoma, the Kennedy Space Center and Washington D.C. Four-dimensional and cloud-to-ground lightning array data provide a total cloud lightning picture (in-cloud, cloud-to-cloud, cloud-to-air, cloud-to-ground) and thus precise LI points for each storm in both time and space. Statistical significance tests are conducted on observed trends for each of the ten LI fields to determine the unique information each field provides in terms of behavior prior to LI. Eight out of ten LI fields exhibited useful information at least 15 min in advance of LI, with 35 min being the average. Statistical tests on these eight fields are compared for separate large geographical areas. IR temperature thresholds are then determined as an outcome, which may be valuable when implementing a LI prediction algorithm into real-time satellite-based systems. The key LI indicators from GOES IR data (as well as 3.9 μm reflectance) will be presented. Beginning in 2010, the feasibility of using the satellite-based LI indicators found in the above analysis to forecast first lightning will be assessed within the Federal Aviation Administration’s (FAA) CoSPA nowcasting system. The goal

  4. New Observations of the Attachment Process in Natural Lightning

    Science.gov (United States)

    Tran, M. D.; Rakov, V. A.; Mallick, S.

    2015-12-01

    We examined the natural-lightning attachment process using high-speed (HS) video records in conjunction with electric field and electric field derivative measurements, all obtained at the Lightning Observatory in Gainesville (LOG), Florida. In different types of strokes (negative first, negative subsequent, and positive first), we observed faintly luminous formations (FLFs) connecting the downward leader to ground. The 2-D lengths of FLFs ranged from 51 to 200 m in negative first strokes (N = 11), from 130 to 908 m in negative subsequent strokes (N=5), and it was 177 m in 1 positive first stroke. The nature of FLFs in negative first strokes differs from that in negative subsequent strokes. We inferred that in first strokes FLFs are mostly composed of positive streamers that developed from the prospective strike point (without a significant upward connecting leader), tens of microseconds prior to the return-stroke onset, while in subsequent strokes they are manifestations of elevated conduction current (of the order of 1 A) in the weakly-conducting defunct channel, occurring in response to the increasing average electric field of the descending leader. The FLF in the positive stroke appeared to be similar to its counterparts in negative first strokes. The streamer connection of the first-stroke leader tip to ground constitutes the break-through phase of the attachment process. Establishment of this connection tens of microseconds prior to the lightning return-stroke onset has never been reported before. We found that the streamer connection did not significantly influence the propagation characteristics of descending leader (and the upward connecting leader, if any), except for always guiding it to the origin of streamers on the grounded object. Implications of the new observations for lightning protection will be discussed. AcknowledgementsThis research was supported in part by NSF and DARPA.

  5. Modeling the spatial differentiation in cloud-to-ground lightning: A case study in Atlanta, Georgia, USA

    Science.gov (United States)

    Strikas, Ona

    Urban cloud-to-ground (CG) lightning enhancement has been well documented for Atlanta, Georgia. This study builds on those investigations using modeling techniques. Numerous styles of analyses and regressions were conducted to establish patterns of CG lightning over the North Georgia region. CG lightning demonstrated clustering for all years of data: 1995--2008. However, the first strike of each day with lightning was randomly distributed according to a Poisson distribution, demonstrating the clustering is not due to permanent features. Attempts were unsuccessful to model CG lightning clusters as either a Matern or Thomas Poisson point process. Regressions of CG lightning with built environment covariates---FAA aviation obstacle locations and heights, population density, road length density, distance to the center of Atlanta, PM10 emissions data, distance to highways, and coal plant locations---as well as natural variables such as projected coordinate easting, northing, and NWS severe thunderstorm status were executed at resolutions of 1km, 2km, 4km, and 8km. Analyses demonstrated significantly higher flash frequency near FAA aviation obstacles. With an R2 value of 0.22, taller obstacles are struck more frequently than shorter obstacles. Regressions with road length density revealed little explanatory power (maximum R2=0.19), but demonstrated a positive correlation independent of scale. A multi-level visualization technique demonstrates the road length density correlation loses accuracy within dense urban corridors. Distance from Atlanta shows a negative correlation, but only at larger scales. Subsetting both regressions by direction reveals a significant difference on the Eastern and Western sides of Atlanta. Subsetting both regressions only to Gwinnett County, Georgia illustrates road length density has no correlation with flash frequency, and distance to Atlanta is still a scale dependent process. PM10 emissions analysis suggests that CG amplification is most

  6. Spatial Variation of the Correlated Color Temperature of Lightning Channel

    OpenAIRE

    Shimoji, Nobuaki; Aoyama, Ryoma

    2014-01-01

    In present work, we propose the analysis method of lightning based on the color analysis. We analyzed the digital still images in which the cloud-to-ground (CG) and intracloud (IC) lightning flashes are shown. Applying some digital image processing techniques, we extracted lightning channels. Then, the correlated color temperature (CCT) of the extracted lightning channels was obtained by mapping digital pixels of the extracted lightning channels to CIE 1931 xy-chromaticity diagram. Our result...

  7. An Integrated 0-1 Hour First-Flash Lightning Nowcasting, Lightning Amount and Lightning Jump Warning Capability

    Science.gov (United States)

    Mecikalski, John; Jewett, Chris; Carey, Larry; Zavodsky, Brad; Stano, Geoffrey

    2015-01-01

    Lightning one of the most dangerous weather-related phenomena, especially as many jobs and activities occur outdoors, presenting risk from a lightning strike. Cloud-to-ground (CG) lightning represents a considerable safety threat to people at airfields, marinas, and outdoor facilities-from airfield personnel, to people attending outdoor stadium events, on beaches and golf courses, to mariners, as well as emergency personnel. Holle et al. (2005) show that 90% of lightning deaths occurred outdoors, while 10% occurred indoors despite the perception of safety when inside buildings. Curran et al. (2000) found that nearly half of fatalities due to weather were related to convective weather in the 1992-1994 timeframe, with lightning causing a large component of the fatalities, in addition to tornadoes and flash flooding. Related to the aviation industry, CG lightning represents a considerable hazard to baggage-handlers, aircraft refuelers, food caterers, and emergency personnel, who all become exposed to the risk of being struck within short time periods while convective storm clouds develop. Airport safety protocols require that ramp operations be modified or discontinued when lightning is in the vicinity (typically 16 km), which becomes very costly and disruptive to flight operations. Therefore, much focus has been paid to nowcasting the first-time initiation and extent of lightning, both of CG and of any lightning (e.g, in-cloud, cloud-to-cloud). For this project three lightning nowcasting methodologies will be combined: (1) a GOESbased 0-1 hour lightning initiation (LI) product (Harris et al. 2010; Iskenderian et al. 2012), (2) a High Resolution Rapid Refresh (HRRR) lightning probability and forecasted lightning flash density product, such that a quantitative amount of lightning (QL) can be assigned to a location of expected LI, and (3) an algorithm that relates Pseudo-GLM data (Stano et al. 2012, 2014) to the so-called "lightning jump" (LJ) methodology (Shultz et al

  8. Study on Lightning Proof of a Vehicle Radar%某车载雷达的防雷研究

    Institute of Scientific and Technical Information of China (English)

    陈世荣; 常继根

    2014-01-01

    The vehicle radar is easy to get lightning strike when it works on dry and wide highland .The meth-od of protection against direct lightning strike and indirect lightning strike is introduced .The three-dimensional model of the protection range of single lightning rod is obtained via MATLAB programming .Changing soil , embedding electrode deeply , adding resistance-reducing agents are introduced for reducing grounding resist-ance of lightning rod on dry land .The lightning proof of vehicle radar in dry land is improved effectively .%针对车载雷达在高地势开阔、干燥地区容易受到雷击威胁的情况,分别介绍了直击雷和感应雷的车载雷达防雷措施,并通过MATLAB进行了单根避雷针保护范围的三维分析;采用更换土壤、深埋电极、添加降阻剂等多种措施降低干燥地区避雷针的接地电阻,有效地提高了干燥地区车载雷达的防雷效果。

  9. Laboratory Investigation on Lightning Flashes to High Voltage Transmission Lines%Laboratory Investigation on Lightning Flashes to High Voltage Transmission Lines

    Institute of Scientific and Technical Information of China (English)

    Thongchai Disyadej; Stanislaw Grzybowski

    2011-01-01

    This paper presents an investigation on the attractive width of high voltage transmission lines to lightning strikes. In order to design the optimal lightning protection, the estimated number of lightning flashes on the line, which is based on its attractive width, needs to be determined. The investigation was performed using experiments with model tests at the Mississippi State University High Voltage Laboratory. For laboratory experiments, a total of 2,100 negative and positive switching impulse voltages were applied to transmission line models from a conducting rod, which represented a lightning downward leader. Different tested models of transmission lines on a scale of 1:100 were used. The effects of overhead ground wires, phase conductors, tower structures, and the magnitude and polarity of lightning strokes were also studied. The attractive width increased gradually with the height of overhead ground wires and towers as well as the magnitude of the lightning stroke current. Impulse polarity had an impact on the at- tractive width, and the attractive width for negative polarity was larger than that {or positive polarity. The taller tower had more effect on flash distribution to transmission lines than the shorter one. The experimental results agree with the actual transmission line observations published in literature. The new expressions for the attractive width of transmission lines, based on the experimental results, were established. The accurate estimation of the attractive width can help electric power utilities plan transmission systems reliably and economically. The detailed description of the back- ground problem, proposed method, experimental results, and analysis are presented in this paper.

  10. Infrasound from lightning measured in Ivory Coast

    Science.gov (United States)

    Farges, T.; Millet, C.; Matoza, R. S.

    2012-04-01

    It is well established that more than 2,000 thunderstorms occur continuously around the world and that about 45 lightning flashes are produced per second over the globe. More than two thirds (42) of the infrasound stations of the International Monitoring System (IMS) of the CTBTO (Comprehensive nuclear Test Ban Treaty Organisation) are now certified and routinely measure signals due to natural activity (e.g., airflow over mountains, aurora, microbaroms, surf, volcanoes, severe weather including lightning flashes, …). Some of the IMS stations are located where worldwide lightning detection networks (e.g. WWLLN) have a weak detection capability but lightning activity is high (e.g. Africa, South America). These infrasound stations are well localised to study lightning flash activity and its disparity, which is a good proxy for global warming. Progress in infrasound array data processing over the past ten years makes such lightning studies possible. For example, Farges and Blanc (2010) show clearly that it is possible to measure lightning infrasound from thunderstorms within a range of distances from the infrasound station. Infrasound from lightning can be detected when the thunderstorm is within about 75 km from the station. The motion of the squall zone is very well measured inside this zone. Up to 25% of lightning flashes can be detected with this technique, giving better results locally than worldwide lightning detection networks. An IMS infrasound station has been installed in Ivory Coast for 9 years. The lightning rate of this region is 10-20 flashes/km2/year from space-based instrument OTD (Christian et al., 2003). Ivory Coast is therefore a good place to study infrasound data associated with lightning activity and its temporal variation. First statistical results will be presented in this paper based on 4 years of data (2005-2009). For short lightning distances (less than 20 km), up to 60 % of lightning detected by WWLLN has been one-to-one correlated

  11. Lightning activity and precipitation structure of hailstorms

    Institute of Scientific and Technical Information of China (English)

    FENG GuiLi; QIE XiuShu; YUAN Tie; NIU ShuZhen

    2007-01-01

    By using the cloud-to-ground (CG) lightning location data from the lightning detection network of Henan Province, surface Doppler radar data and standard orbit data of PR, TMI and LIS on TRMM satellite, the apatjal and temporal characteristice of CG lightning flashes in 10 severe hailstorms are analyzed. The results show that the percentage of+CG lightning in these hailstorms is high with an average value of 45.5%.There is a distinct increase in CG flash rate during the rapid development stage of hailstorms. The hailstone falling corresponds to an active positive flash period, and the increase of+CG flash rate is generally accompanied with a decrease of-CG flash rate. The flash rate declines rapidly during the dissipating stage of hailstorms. The precipitation structure and lightning activity in two typical hailstorms are studied in detail. It is found that strong convective cells with reflectivity greater than 30dBZ mainly are situated in the front region of hailstorms, whereas the trailing stratiform region is in the rear part of the hailstorme. The maximum heights of echo top are higher than 14km.Convective rain contributes much more rainfall to the total than stratiform rain, and the convective rain takes about 85% and 97% of the total in the two cases, respectively. Total lightning in the hailstorms is very active with the flash rate up to 183 fl/min and 55 fl/min, respectively. The results also indicate that most lightning flashes occurred in the echo region greater than 30dBZ and its immediate periphery. The probability of lightning occurrence is 20 times higher in the convective region than in the stratiform region. The result suggests that the lightning information is helpful to the identification of convective rain region. The linear relationship between flash rate and ice water content is disclosed primarily.

  12. Lightning activity and precipitation structure of hailstorms

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    By using the cloud-to-ground (CG) lightning location data from the lightning detection network of He- nan Province, surface Doppler radar data and standard orbit data of PR, TMI and LIS on TRMM satellite, the spatial and temporal characteristics of CG lightning flashes in 10 severe hailstorms are analyzed. The results show that the percentage of +CG lightning in these hailstorms is high with an average value of 45.5%. There is a distinct increase in CG flash rate during the rapid development stage of hailstorms. The hailstone falling corresponds to an active positive flash period, and the increase of +CG flash rate is generally accompanied with a decrease of –CG flash rate. The flash rate declines rapidly during the dissipating stage of hailstorms. The precipitation structure and lightning activity in two typical hail- storms are studied in detail. It is found that strong convective cells with reflectivity greater than 30dBZ mainly are situated in the front region of hailstorms, whereas the trailing stratiform region is in the rear part of the hailstorms. The maximum heights of echo top are higher than 14 km. Convective rain con- tributes much more rainfall to the total than stratiform rain, and the convective rain takes about 85% and 97% of the total in the two cases, respectively. Total lightning in the hailstorms is very active with the flash rate up to 183 fl/min and 55 fl/min, respectively. The results also indicate that most lightning flashes occurred in the echo region greater than 30 dBZ and its immediate periphery. The probability of lightning occurrence is 20 times higher in the convective region than in the stratiform region. The result suggests that the lightning information is helpful to the identification of convective rain region. The linear relationship between flash rate and ice water content is disclosed primarily.

  13. FAA-NASA Sixth International Conference on the Continued Airworthiness of Aircraft Structures

    Science.gov (United States)

    1995-12-01

    British Airways Human Factors in Aviation Maintenance: Current FAA Research .............................. 91 William T. Shepherd, Federal Aviation...Development of Advanced Structural Analysis Methodologies for Predicting W idespread Fatigue Damage in Aircraft Structures...where satellite communications to transmit aircraft position data derived from GPS directly to controllers via data link. On June 21, FAA and Qantas

  14. 78 FR 63276 - Interim Policy, FAA Review of Solar Energy System Projects on Federally Obligated Airports

    Science.gov (United States)

    2013-10-23

    ... Federal Aviation Administration Interim Policy, FAA Review of Solar Energy System Projects on Federally... federally obligated airports to construct solar energy systems on airport property. FAA is adopting an... for measuring ocular impact of proposed solar energy systems which are effective upon publication....

  15. Inferring the correlation between lightning events and voltage dips in distribution networks

    Energy Technology Data Exchange (ETDEWEB)

    Nucci, C.A. [University of Bologna (Italy)], E-mail: carloalberto.nucci@unibo.it

    2007-07-01

    To appropriately infer the correlation between lightning events and flashover/voltage dips on real distribution networks, data coming from lightning location systems are certainly needed, but need to be complemented on the one hand by data coming from distributed measurement systems able to record both protection manoeuvres and lightning-originated transients, and on the other hand by accurate calculation results. Additionally, the analysis needs to be performed on a statistical basis. The paper illustrates the main concepts used in developing a procedure aimed at inferring the above mentioned correlation, which is based on the integrated use of experimental data obtained from the Italian lightning location system CESI-SIRF, a monitoring system of relay operation, a distributed monitoring system of lightning-induced transients and of calculations performed using the LIOV-EMTP code. The application of the procedure to the portion of a real distribution network located in Italy in a high level keraunic area is presented by making use of some CESI-SIRF-detected events. (author)

  16. Direct Measurement of Lightning Current Through a Wind-Turbine-Generator-Structure

    Science.gov (United States)

    Shiraishi, Yasuhiro; Otsuka, Takahiro

    In recent years, a wind turbine generator system is expected as one of clean energies to solve energy resources and global environmental problems. Those systems are installed in places with a strong wind. However, those places have also many winter lightning, which cause heavy damage to electric power facilities. Especially, these system in dozen of meter height are facing to severe problems such as an outage of the electric power and a maintenance check against lightning damage. In order to supply the stable energy, it is necessary to set up a lightning protection of the system. So, we developed the large diameter Rogowski coil, which can surround the steel pipe of the leg, and proved the performance by experiment. And using this Rogowski coil, we observed lightning current in some wind turbine generator systems in Japan. As the results of these observations, we got some observation data of lightning current, which struck the wind turbine generator system. This paper reports these observation techniques and results.

  17. Numerical modeling of initiation of lightning leaders from tall structures by sprite-producing lightning discharges

    Science.gov (United States)

    Pasko, V. P.

    2011-12-01

    It is well established by now that large charge transfers between cloud and ground in positive cloud-to-ground lightning discharges (+CGs) can lead to transient electric field enhancements at mesospheric and lower ionospheric altitudes. In these events the electric field can exceed the conventional breakdown field and lead to formation of transient luminous events referred to as sprites and sprite halos [e.g., Qin et al., JGR, 116, A06305, 2011, and references therein]. Stanley and Heavner [Proc. 12th International Conference on Atmospheric Electricity, Versailles, France, 2003] reported that the large and rapid charge transfer of +CGs producing sprites can also initiate upward positive leaders from tall structures. These authors also presented data analysis indicating that structures with >400 m height have a significantly enhanced probability of launching upward positive leaders that may culminate in a -CG return stroke to the structure. The effect can be understood by considering the field intensification at the top of the tall structure combined with fast application of the field preventing formation and shielding effects of ion corona [Brook et al., JGR, 66, 3967, 1961]. In the present work we utilize the most recent modeling approaches developed at Penn State [e.g., Riousset et al., JGR, 115, A00E10, 2010] to quantify the conditions leading to initiation of positive leaders from tall structures following sprite-producing +CGs. Experiments show that the streamer zone transforms into leader when voltage drop along the streamer zone exceeds 400 kV [e.g., Aleksandrov et al., J. Phys. D: Appl. Phys., 38, 1225, 2005]. For a formed leader half of the voltage drops in the streamer zone, and another half in free space ahead of the streamer zone [Bazelyan and Raizer, Lightning physics and lightning protection, p. 62, 2000]. In our analysis therefore we assume that minimum voltage at the tip of the tower should exceed 800 kV for sustainment of upward propagating leader

  18. Lightning strike-induced brachial plexopathy.

    Science.gov (United States)

    Bhargava, Amita N; Kasundra, Gaurav M; Khichar, Subhakaran; Bhushan, Bharat S K

    2014-10-01

    We describe a patient who presented with a history of lightning strike injury. Following the injury, he sustained acute right upper limb weakness with pain. Clinically, the lesion was located to the upper and middle trunk of the right brachial plexus, and the same confirmed with electrophysiological studies. Nerve damage due to lightning injuries is considered very rare, and a plexus damage has been described infrequently, if ever. Thus, the proposed hypothesis that lightning rarely causes neuropathy, as against high-voltage electric current, due to its shorter duration of exposure not causing severe burns which lead to nerve damage, needs to be reconsidered.

  19. Accuracy of LLP system and lightning frequency map evaluated from transmission line faults; Rakurai ichi hyotei system no seido to rakurai hindo map no sodensen torippu jiko ni motozuku hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Shinjo, K.; Wakai, T.; Sakai, T. [Hokuriku Electric Power Co., Inc., Toyama (Japan)] Ishii, M. [Tokyo Univ. (Japan)

    1997-10-20

    Accuracy of an LLP system and a lightning frequency map is evaluated by using transmission line faults in Hokuriku area from November in 1993 to October in 1996. The accuracy and efficiency of the system were calculated by statistical methods. From the above results, the lightning frequency map with 10 minutes meshes was proved capable of replacing the Isokeraunic Level Map with 15 minutes meshes used now for lightning protection design. However, the correlation between the number of detected lightning flashes and transmission line faults in each mesh was found to be week. This result suggests that more detailed analysis taking account of the length of transmission lines in each mesh is necessary. The correlation is stronger in winter than in summer, despite the fact that there is difference in the lightning current distribution in each mesh in winter. This characteristic can be explained if upward flashes from transmission lines are dominant among lightning faults in winter. 19 refs., 11 figs., 6 tabs.

  20. Lightning Attachment Estimation to Wind Turbines by Utilizing Lightning Location Systems

    DEFF Research Database (Denmark)

    Vogel, Stephan; Holbøll, Joachim; Lopez, Javier

    2016-01-01

    The goal of a lightning exposure assessment is to identify the number, type and characteristics of lightning discharges to a certain structure. There are various Lightning Location System (LLS) technologies available, each of them are characterized by individual performance characteristics...... three different wind power plant locations are analyzed and the impact of varying data qualities is evaluated regarding the ability to detect upward lightning. This work provides a variety of background information which is relevant to the exposure assessment of wind turbine and includes practical...

  1. Federal Aviation Administration (FAA airworthiness certification for ceramic matrix composite components in civil aircraft systems

    Directory of Open Access Journals (Sweden)

    Gonczy Stephen T.

    2015-01-01

    Full Text Available Ceramic matrix composites (CMCs are being designed and developed for engine and exhaust components in commercial aviation, because they offer higher temperature capabilities, weight savings, and improved durability compared to metals. The United States Federal Aviation Administration (FAA issues and enforces regulations and minimum standards covering the safe manufacture, operation, and maintenance of civil aircraft. As new materials, these ceramic composite components will have to meet the certification regulations of the FAA for “airworthiness”. The FAA certification process is defined in the Federal Aviation Regulations (Title 14 of the Code of Federal Regulations, FAA policy statements, orders, advisory circulars, technical standard orders, and FAA airworthiness directives. These regulations and documents provide the fundamental requirements and guidelines for design, testing, manufacture, quality assurance, registration, operation, inspection, maintenance, and repair of aircraft systems and parts. For metallic parts in aircraft, the FAA certification and compliance process is well-established for type and airworthiness certification, using ASTM and SAE standards, the MMPDS data handbook, and FAA advisory circulars. In a similar manner for polymer matrix composites (PMC, the PMC industry and the FAA have jointly developed and are refining parallel guidelines for polymer matrix composites (PMCs, using guidance in FAA circulars and the CMH-17 PMC handbook. These documents discuss design methods and codes, material testing, property data development, life/durability assessment, production processes, QA procedures, inspection methods, operational limits, and repairs for PMCs. For ceramic composites, the FAA and the CMC and aerospace community are working together (primarily through the CMH-17 CMC handbook to define and codify key design, production, and regulatory issues that have to be addressed in the certification of CMC components in

  2. Lightning activity during the 1999 Superior derecho

    Science.gov (United States)

    Price, Colin G.; Murphy, Brian P.

    2002-12-01

    On 4 July 1999, a severe convective windstorm, known as a derecho, caused extensive damage to forested regions along the United States/Canada border, west of Lake Superior. There were 665,000 acres of forest destroyed in the Boundary Waters Canoe Area Wilderness (BWCAW) in Minnesota and Quetico Provincial Park in Canada, with approximately 12.5 million trees blown down. This storm resulted in additional severe weather before and after the occurrence of the derecho, with continuous cloud-to-ground (CG) lightning occurring for more than 34 hours during its path across North America. At the time of the derecho the percentage of positive cloud-to-ground (+CG) lightning measured by the Canadian Lightning Detection Network (CLDN) was greater than 70% for more than three hours, with peak values reaching 97% positive CG lightning. Such high ratios of +CG are rare, and may be useful indicators of severe weather.

  3. Lightning phenomenology in the Tampa Bay Area

    Science.gov (United States)

    Peckham, D. W.; Uman, M. A.; Wilcox, C. E., Jr.

    1984-01-01

    A commercial lightning-locating system (LLS) was employed in the study of lightning phenomenology in the Tampa Bay area of Florida. The LLS output included the time, location, number of strokes per flash, and initial peak magnetic field value of first strokes for lightning ground flashes lowering negative charge. Attention is given to the design and the operation of the LLS, and the experimental results. Measured properties of each of 111 storms are given in a number of tables. It was observed that the apparent motion associated with the lightning activity in storm systems was not due to the motion of the individual single-peak and multiple-peak storms but rather to the successive growth of new storms near previously active storms.

  4. Central hyperadrenergic state after lightning strike.

    Science.gov (United States)

    Parsaik, Ajay K; Ahlskog, J Eric; Singer, Wolfgang; Gelfman, Russell; Sheldon, Seth H; Seime, Richard J; Craft, Jennifer M; Staab, Jeffrey P; Kantor, Birgit; Low, Phillip A

    2013-08-01

    To describe and review autonomic complications of lightning strike. Case report and laboratory data including autonomic function tests in a subject who was struck by lightning. A 24-year-old man was struck by lightning. Following that, he developed dysautonomia, with persistent inappropriate sinus tachycardia and autonomic storms, as well as posttraumatic stress disorder (PTSD) and functional neurologic problems. The combination of persistent sinus tachycardia and episodic exacerbations associated with hypertension, diaphoresis, and agitation was highly suggestive of a central hyperadrenergic state with superimposed autonomic storms. Whether the additional PTSD and functional neurologic deficits were due to a direct effect of the lightning strike on the central nervous system or a secondary response is open to speculation.

  5. Lightning frequency over the Italian peninsula

    Science.gov (United States)

    Turoldo, F.; Stel, F.; Giaiotti, D. B.; Bernardi, M.; Adamo, C.; Rovelli, C.; Dietrich, S.; Goi, D.

    2010-09-01

    The aim of this work is to analize the spatial frequency of lightning over Italy and to interpret the observed features in relationship with topography and with the climatic characteristics of the area. The data used to perform this analysis are : i) cloud to ground measurem ents (CG) from 1995 to 2000 given by CESI/SIRF (Sistem a Italiano Rilevamento Fulmini); ii) total flash measurements from 1995 to 2000 obtained trough the OTD system (Optical Transient Detector) given by NASA; iii) topography measurements obtained trough the ETOPO -2 database downloaded from NOAA. Both the yearly number of positive and negative CG lightning decrease with the increasing of topographic height. The number of positive and negative CG lightning decreases with the same derivative even if it seems that only below 1000 m it is possible to reach ratios between positive over negative CG lightning higher than 1. These values are observed only in the North African area present in the ranges of our analysis , that is from longitude 5 to 11 °E and from latitude 36 to 37 °N. Future studies will confirm if this is a real effect or an observational bias. The behavior of total lightning activity (IC and CG) in relationship with CG lightning activity and with topography is studied by means of OTD data. Being OTD data retrieved trough satellites, the analysis is done making us e of the flash rate per squared kilometer and per year instead of the number of lightning. Flash rate is computed using data on a re solution of 0.5°x0.5° and keping into account the changes in the surface due to the changes in latitude and longitude. This work confirms the observation (made even by other authors) that CG lightning frequency decreases as topographic height increases. A similar trend is found in total lightning flash rate, which is essentially due to the contribution of IC lightning. These observations are explained assuming that thunderstorm activity decreases with the increasing of topographic height

  6. Development of a Technique for Representing Lightning Arresters in the Surge Simulations based on the FDTD Method and its Application to the Calculation of Lightning-Induced Voltages on a Distribution Line

    Science.gov (United States)

    Tatematsu, Akiyoshi; Noda, Taku

    Recently, the FDTD (Finite Difference Time Domain) method, which directly solves Maxwell's equations, has been applied to lightning surge problems involving electrical wires in three-dimensional arrangements, such as power and telecommunication circuits. Lightning arresters are installed to protect the circuits from abnormal voltages due to lightning, for example. We have already proposed a technique for representing a lightning arrester in the FDTD method. However, this technique simply represents the V-I characteristics of the arrester using just three parameters and requires a method for avoiding the numerical oscillation due to the nonlinear characteristics of the arrester. In this paper, we propose a new technique for representing the V-I characteristics of the arrester in detail using the piecewise linear function defined by several points and for improving the numerical stability without the method for avoiding the numerical oscillation. Using a test circuit, the proposed technique is validated by comparing the results calculated by the FDTD method with those by the EMTP (ElectroMagnetic Transients Program) which is a circuit-theory-based simulation program. Finally, as an example of applying the proposed technique, we calculate lightning-induced voltages on a distribution line with a lightning arrester. The calculated results by the FDTD method agree well with those by a conventional method based on circuit theroy.

  7. Scientific Lightning Detection Network for Kazakhstan

    Science.gov (United States)

    Streltsov, A. V.; Lozbin, A.; Inchin, A.; Shpadi, Y.; Inchin, P.; Shpadi, M.; Ayazbayev, G.; Bykayev, R.; Mailibayeva, L.

    2015-12-01

    In the frame of grant financing of the scientific research in 2015-2017 the project "To Develop Electromagnetic System for lightning location and atmosphere-lithosphere coupling research" was found. The project was start in January, 2015 and should be done during 3 years. The purpose is to create a system of electromagnetic measurements for lightning location and atmosphere-lithosphere coupling research consisting of a network of electric and magnetic sensors and the dedicated complex for data processing and transfer to the end user. The main tasks are to set several points for electromagnetic measurements with 100-200 km distance between them, to develop equipment for these points, to develop the techniques and software for lightning location (Time-of-arrival and Direction Finding (TOA+DF)) and provide a lightning activity research in North Tien-Shan region with respect to seismicity and other natural and manmade activities. Also, it is planned to use lightning data for Global Electric Circuit (GEC) investigation. Currently, there are lightning detection networks in many countries. In Kazakhstan we have only separate units in airports. So, we don't have full lightning information for our region. It is planned, to setup 8-10 measurement points with magnetic and electric filed antennas for VLF range. The final data set should be including each stroke location, time, type (CG+, CG-, CC+ or CC-) and waveform from each station. As the magnetic field lightning antenna the ferrite rod VLF antenna will be used. As the electric field antenna the wide range antenna with specific frequencies filters will be used. For true event detection TOA and DF methods needs detected stroke from minimum 4 stations. In this case we can get location accuracy about 2-3 km and better.

  8. Z-M in Lightning Forecasting

    Science.gov (United States)

    2009-03-01

    reflectivity 20-25 dBZ which maintained their electric field for many tens of minutes well downstream of the 34 convective core. Dye and Willett (2007...concede that although the two anvils did not produce lightning, the electric field was probably sufficient to trigger lightning for many tens of minutes...online at: http://ghrc.msfc.nasa.gov/ uso /readme/ldar.html.] Greene, Douglas R. and Robert A. Clark, 1972: Vertically integrated liquid water—A new

  9. A Fossilized Energy Distribution of Lightning

    Science.gov (United States)

    Pasek, Matthew A.; Hurst, Marc

    2016-07-01

    When lightning strikes soil, it may generate a cylindrical tube of glass known as a fulgurite. The morphology of a fulgurite is ultimately a consequence of the energy of the lightning strike that formed it, and hence fulgurites may be useful in elucidating the energy distribution frequency of cloud-to-ground lightning. Fulgurites from sand mines in Polk County, Florida, USA were collected and analyzed to determine morphologic properties. Here we show that the energy per unit length of lightning strikes within quartz sand has a geometric mean of ~1.0 MJ/m, and that the distribution is lognormal with respect to energy per length and frequency. Energy per length is determined from fulgurites as a function of diameter, and frequency is determined both by cumulative number and by cumulative length. This distribution parallels those determined for a number of lightning parameters measured in actual atmospheric discharge events, such as charge transferred, voltage, and action integral. This methodology suggests a potential useful pathway for elucidating lightning energy and damage potential of strikes.

  10. On the initiation of lightning in thunderclouds.

    Science.gov (United States)

    Chilingarian, Ashot; Chilingaryan, Suren; Karapetyan, Tigran; Kozliner, Lev; Khanikyants, Yeghia; Hovsepyan, Gagik; Pokhsraryan, David; Soghomonyan, Suren

    2017-05-02

    The relationship of lightning and elementary particle fluxes in the thunderclouds is not fully understood to date. Using the particle beams (the so-called Thunderstorm Ground Enhancements - TGEs) as a probe we investigate the characteristics of the interrelated atmospheric processes. The well-known effect of the TGE dynamics is the abrupt termination of the particle flux by the lightning flash. With new precise electronics, we can see that particle flux decline occurred simultaneously with the rearranging of the charge centers in the cloud. The analysis of the TGE energy spectra before and after the lightning demonstrates that the high-energy part of the TGE energy spectra disappeared just after lightning. The decline of particle flux coincides on millisecond time scale with first atmospheric discharges and we can conclude that Relativistic Runaway Electron Avalanches (RREA) in the thundercloud assist initiation of the negative cloud to ground lightning. Thus, RREA can provide enough ionization to play a significant role in the unleashing of the lightning flash.

  11. Process Analysis of Double Circuit Transmission Line Trip-out on the Same Tower Due to Lightning

    Institute of Scientific and Technical Information of China (English)

    DUAN Da-peng; REN Zhi-gang; WANG Peng; YE Kuan; CHANG Xiao-qi; LI Wei

    2011-01-01

    In recent years,several failures of double circuit transmission line on the same tower due to lightning were happened in Beijing power grid.Although it can be reclosed successful,the lightning strike caused a grave threat to the power grid security.The cause of the accident and the accident process were studied for the sake of further understanding of the impact of lightning on power grid.As an example,110 kV double circuit transmission line(Xilong-line) was analyzed.At first,the system topology was given.Through the analysis on relay protection actions and the fault recorder data,over voltageon the insulator strings was calculated.Based on the analysis and the calculation,accident cause and the process were presented respectively.Secondly,it comes to the conclusion that the lightning failure was caused by counterattack.The wave of the lightning over voltage would spread to the not grounded neutral point of the transformers,and make the neutral protective gap breakdown,then cause freewheeling with the frequency of 50 Hz.As results of the relay protection,the double circuit transmission line all tripped out.Finally,the causes of the accident were proposed that included terrain features,large corner towers,strong thunderstorm weather and poor grounded contact of the tower.

  12. Lightning NOx Production in CMAQ Part I – Using Hourly NLDN Lightning Strike Data

    Science.gov (United States)

    Lightning-produced nitrogen oxides (NOX=NO+NO2) in the middle and upper troposphere play an essential role in the production of ozone (O3) and influence the oxidizing capacity of the troposphere. Despite much effort in both observing and modeling lightning NOX during the past dec...

  13. Multiple Lightning Discharges in Wind Turbines Associated with Nearby Cloud-to-Ground Lightning

    DEFF Research Database (Denmark)

    Candela Garolera, Anna; Cummins, Kenneth L.; Madsen, Søren Find;

    2015-01-01

    This paper presents the analysis of five events where simultaneous lightning currents were registered in different wind turbines of a wind farm with lightning monitoring equipment installed. Measurements from current monitoring devices installed at the wind turbines and observations from auto-tri...

  14. Lightning NOx Production in CMAQ Part I – Using Hourly NLDN Lightning Strike Data

    Science.gov (United States)

    Lightning-produced nitrogen oxides (NOX=NO+NO2) in the middle and upper troposphere play an essential role in the production of ozone (O3) and influence the oxidizing capacity of the troposphere. Despite much effort in both observing and modeling lightning NOX during the past dec...

  15. Spatiotemporal characteristics of positive cloud-to-ground lightning discharges and bidirectional leader of the lightning

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The three-dimension spatiotemporal development characteristics of positive cloud-toground (CG) lightning discharges have been analyzed by using the data measured by the lightning mapping array system with high time and space resolution. The results indicate that a positive CG lightning discharge can be divided into three stages based on the characteristics of its development. The first stage is discharge process in cloud with a long duration preceding the return stroke. This process with an average of 370 ms propagated at velocity of 105 m/s and produced intensive radiation with a magnitude equal to that of the negative leader. During this stage, the lightning channels developed horizontally in the positive charge region with few branches as the negative polarity breakdown. During the stage after the return stroke of the positive CG lightning, the lightning channels propagated at velocity of 2 times faster than that before the return stroke. This stage involved lots of positive fast impulses and corresponded to the continuing current process producing less and dispersed radiation points and more intensive radiation powers. During the final stage of the positive CG lightning, the lightning channels developed at velocity equal to that before the return stroke and the radiation points appeared mainly at the ends of channel. The spatiotemporal development characteristics of the positive CG lightning are very different from that of the negative CG lightning. All of the radiation points of the positive CG lightning appeared in the positive charge region of cloud. Little or no radiation was detected during the positive leader just before the return stroke. The duration of the positive CG lightning was an average of 730 ms. The positive CG lightning discharges with lasting time of 500-600 ms were 43%. 90% of the positive CG lightning discharges involved one return stroke, the most return stroke number being four. The current of the return stroke was an average of 36.5 k

  16. Franklin Lecture: Lightning in Planetary Atmospheres

    Science.gov (United States)

    Gurnett, D. A.

    2006-12-01

    A broad overview is given of lightning in planetary atmospheres. Searches for lightning using spacecraft-borne instrumentation have now been conducted at almost all of the planets in the solar system, the exceptions being Mercury, which has no appreciable atmosphere, and Pluto which has not yet been visited by a spacecraft. The techniques used include (1) imaging observations to detect optical flashes produced by lightning; (2) high-frequency radio measurements to detect the impulsive broadband radio bursts, called spherics, produced by lightning discharges; and (3) low-frequency plasma wave measurements to detect the whistling tones, called whistlers, produced by lightning. Using these techniques, lightning has been reported at five planets other than Earth. These are: Venus, Jupiter, Saturn, Uranus, and Neptune. Of these, the existence of lightning at Venus is doubtful, and the evidence of lightning at Neptune is at best marginal. Jupiter and Saturn have by far the most intense and well documented lightning activity. During the Voyager 1 flyby of Jupiter, whistlers and intense optical flashes, comparable to those from terrestrial superbolts, were observed by the plasma wave and optical imaging instruments. However, no impulsive high-frequency radio bursts were observed. Two factors may be responsible for the absence of high-frequency radio signals: (1) the very strong magnetic field of Jupiter, which blocks the escape of the extra-ordinary mode; and (2) the relatively high electron collision frequency in the ionosphere, which increases the absorption of radio waves. During the Voyager 1 and 2 flybys of Saturn many very strong high-frequency radio bursts, called Saturn Electrostatic Discharges (SEDs), were detected. Although the origin of these impulsive radio bursts was initially uncertain, strong evidence now exists that SEDs are produced by lightning. Recent optical imaging and radio measurements from the Cassini spacecraft clearly show that SEDs originate from

  17. Lightning: Nature's Probe of Severe Weather for Research and Operations

    Science.gov (United States)

    Blakeslee, R.J.

    2007-01-01

    Lightning, the energetic and broadband electrical discharge produced by thunderstorms, provides a natural remote sensing signal for the study of severe storms and related phenomena on global, regional and local scales. Using this strong signal- one of nature's own probes of severe weather -lightning measurements prove to be straightforward and take advantage of a variety of measurement techniques that have advanced considerably in recent years. We briefly review some of the leading lightning detection systems including satellite-based optical detectors such as the Lightning Imaging Sensor, and ground-based radio frequency systems such as Vaisala's National Lightning Detection Network (NLDN), long range lightning detection systems, and the Lightning Mapping Array (LMA) networks. In addition, we examine some of the exciting new research results and operational capabilities (e.g., shortened tornado warning lead times) derived from these observations. Finally we look forward to the next measurement advance - lightning observations from geostationary orbit.

  18. Research and Application on Lightning Protection Grounding Technology for Large Scale Photovol-taic Power Generation System in Mountainous Areas%山区大型光伏发电系统防雷接地技术探究与应用

    Institute of Scientific and Technical Information of China (English)

    孙录贵

    2015-01-01

    Photovoltaic power generation system is based on a film area of solar panels. In order to avoid the waste of land resources,generally large-scale solar photovoltaic generation stations are built on the hillside far away from the town,where is empty,without high-buildings,in high risk area of lightning.It is especially important to make sure the quality of lightning protection earthing electrodes for the electrical resistivity of mountains soil is very high ,fur-thermore it with largescope of radiation,much electrical equipment in power station.In this article,explored the pho-tovoltaic power generation system on the slope of the high resistance of grounding technology theory method by twen-ty MW ground actual problems in the first phase of the photovoltaic powers station project in Xuanyang village Xieji town Yongqiao district. Make the photovoltaic power grounding system in accordance with the requirements of the drawings design basis.Achieve"adjust measures to local conditions,economic and reasonable". Finally the popular-ization and application of the conclution can be maken.%光伏发电系统需要成片区的太阳能电池板作为基础,为了尽量减小对土地的浪费,大型太阳能光伏发电站往往都建设在偏离城镇的山坡上,环境空旷,周边没有高大建筑物防护,其本身就处于雷击高风险区域,而且山区土壤电阻率较高,辐射范围大,电站内电气设备较多,因而确保防雷接地质量尤为重要.该文通过分析埇桥区谢集乡宣杨村20MW地面光伏电站项目一期工程遇到的实际问题,探究在高阻区的山坡上完成光伏发电系统防雷接地技术的方法,使光伏发电接地系统在符合图纸设计要求的基础上,做到"因地制宜、经济合理"并加以推广运用.

  19. An Operational Perspective of Total Lightning Information

    Science.gov (United States)

    Nadler, David J.; Darden, Christopher B.; Stano, Geoffrey; Buechler, Dennis E.

    2009-01-01

    The close and productive collaborations between the NWS Warning and Forecast Office, the Short Term Prediction and Research Transition Center at NASA Marshall Space Flight Center and the University of Alabama in Huntsville have provided a unique opportunity for science sharing and technology transfer. One significant technology transfer that has provided immediate benefits to NWS forecast and warning operations is the use of data from the North Alabama Lightning Mapping Array. This network consists of ten VHF receivers deployed across northern Alabama and a base station located at the National Space Science and Technology Center. Preliminary investigations done at WFO Huntsville, along with other similar total lightning networks across the country, have shown distinct correlations between the time rate-of-change of total lightning and trends in intensity/severity of the parent convective cell. Since May 2003 when WFO HUN began receiving these data - in conjunction with other more traditional remotely sensed data (radar, satellite, and surface observations) -- have improved the situational awareness of the WFO staff. The use of total lightning information, either from current ground based systems or future space borne instrumentation, may substantially contribute to the NWS mission, by enhancing severe weather warning and decision-making processes. Operational use of the data has been maximized at WFO Huntsville through a process that includes forecaster training, product implementation, and post event analysis and assessments. Since receiving these data, over 50 surveys have been completed highlighting the use of total lightning information during significant events across the Tennessee Valley. In addition, around 150 specific cases of interest have been archived for collaborative post storm analysis. From these datasets, detailed trending information from radar and total lightning can be compared to corresponding damage reports. This presentation will emphasize

  20. Lightning chemistry on Earth-like exoplanets

    Science.gov (United States)

    Ardaseva, Aleksandra; Rimmer, Paul B.; Waldmann, Ingo; Rocchetto, Marco; Yurchenko, Sergey N.; Helling, Christiane; Tennyson, Jonathan

    2017-09-01

    We present a model for lightning shock-induced chemistry that can be applied to atmospheres of arbitrary H/C/N/O chemistry, hence for extrasolar planets and brown dwarfs. The model couples hydrodynamics and the STAND2015 kinetic gas-phase chemistry. For an exoplanet analogue to the contemporary Earth, our model predicts NO and NO2 yields in agreement with observation. We predict height-dependent mixing ratios during a storm soon after a lightning shock of NO ≈10-3 at 40 km and NO2 ≈10-4 below 40 km, with O3 reduced to trace quantities (≪10-10). For an Earth-like exoplanet with a CO2/N2 dominated atmosphere and with an extremely intense lightning storm over its entire surface, we predict significant changes in the amount of NO, NO2, O3, H2O, H2 and predict a significant abundance of C2N. We find that, for the Early Earth, O2 is formed in large quantities by lightning but is rapidly processed by the photochemistry, consistent with previous work on lightning. The chemical effect of persistent global lightning storms are predicted to be significant, primarily due to NO2, with the largest spectral features present at ∼3.4 and ∼6.2 μm. The features within the transmission spectrum are on the order of 1 ppm and therefore are not likely detectable with the James Webb Space Telescope. Depending on its spectral properties, C2N could be a key tracer for lightning on Earth-like exoplanets with a N2/CO2 bulk atmosphere, unless destroyed by yet unknown chemical reactions.

  1. Lightning-induced overvoltages in low-voltage systems

    Energy Technology Data Exchange (ETDEWEB)

    Hoeidalen, Hans Kristian

    1997-12-31

    Lightning-induced overvoltages (LIOs) are a main source of failures in low-voltage overhead line systems. This thesis deals mainly with calculations of LIOs aiming to enable the design of a proper voltage protection. Models for calculation of LIOs are adapted from the literature or developed based on measurements. The models used are believed to be fairly accurate for the first few microseconds, which is usually sufficient for predicting the maximum induced voltage in the system. The lightning channel is modelled by the Modified Transmission Line (MTL) model with the Transmission Line (TL) model as a special case. The coupling between the electrical fields from a lightning channel and an overhead line is modelled by Agrawal`s model. The attenuation of electrical fields over a lossy ground is modelled by Norton`s- or the Surface Impedance methods. The validity of all the applied models is analysed. In addition, measurements have been performed in order to develop models of distribution transformers and low-voltage power installation (LVPI) networks. Simple models of typical transformers and LVPIs are developed for calculations when specific data are unavailable. The practical range of values and its influence on the LIOs in a system is investigated. The main frequency range of interest related to LIOs is 10 kHz - 1 MHz in which all the models are accurate. The adapted or developed models are used to calculate LIOs in low-voltage systems. The influence of various key parameters in the system is investigated. Most important are the return stroke amplitude and rise time, the overhead line height and location, the termination of overhead line segments, neutral grounding, and the ground conductivity. 135 refs., 136 figs., 12 tabs.

  2. North Alabama Total Lightning Climatology in Support of Lightning Safety Operations

    Science.gov (United States)

    Stano, G. T.; Schultz, C. J.; Koshak, W. J.

    2015-12-01

    The North Alabama Lightning Mapping Array (NALMA) was installed in 2001 to observe total lightning (cloud-to-ground and intra-cloud) and study its relationship to convective activity. NALMA has served as ground-truth for the Tropical Rainfall Measuring Mission Lightning Imager (TRMM-LIS) and will again for the GOES-R Geostationary Lightning Mapper (GLM). Also, NASA's Short-term Prediction Research and Transition Center (SPoRT) has transitioned these data to National Weather Service Weather Forecast Offices to evaluate the impact in operations since 2003. This study focuses on seasonal and diurnal observations from NALMA's 14 year history. This is initially intended to improve lightning safety at Marshall Space Flight Center, but has other potential applications. Improvements will be made by creating a dataset to investigate temporal, spatial, and seasonal patterns in total lightning over the Tennessee Valley, compare these observations to background environmental parameters and the TRMM-LIS climatology, and investigate applying these data to specific points of interest. Unique characteristics, such as flash extent density and length of flashes can be investigated, which are unavailable from other lightning networks like the National Lightning Detection Network (NLDN). The NALMA and NLDN data can be combined such that end users can use total lightning to gain lead time on the initial cloud-to-ground flash of a storm and identify if lightning is extending far from the storm's core. This spatial extent can be analyzed to determine how often intra-cloud activity may impinge on a region of interest and how often a cloud-to-ground strike may occur in the region. The seasonal and diurnal lightning maps can aid with planning of various experiments or tests that often require some knowledge about future weather patterns months in advance. The main goal is to develop a protocol to enhance lightning safety everywhere once the Geostationary Lightning Mapper (GLM) is on orbit

  3. Modelling lightning caused transmission line outages in Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Wu, M.; Shen, S.S.P. [Alberta Univ., Edmonton, AB (Canada). Dept. of Mathematical and Statistical Sciences; Koval, D.O. [Alberta Univ., Edmonton, AB (Canada). Dept. of Electrical Engineering

    2005-07-01

    The characteristics of lightning and the relationship between lightning and transmission line outages is not fully understood by utility planners. This study used 20 year data sets of lightning events to investigate the spatial and temporal patterns of lightning in Alberta. Studies of geographical and temporal characteristics of lightning caused transmission line outages for several voltage level transmission lines were also examined. A lasso regression variable selection procedure and Cp criterion were used to model the duration of the lightning-caused transmission line outages as a function of weather and lightning patterns. The province was divided into 110 by 110 grids, and lightning variables were calculated for each cell. All the lightning variables for each cell were then averaged based on their areas. The overall cloud-ground lightning flashes 20-year mean frequency and the physical locations of power transmission lines were then plotted. Estimated probability density functions of the duration of lightning caused transmission line outages were classified by their voltage levels. The study showed that the characteristics of the lightning caused outages were different for different voltage levels of the transmission lines. Results suggested that the findings will have a significant impact on the accuracy of reliability methodologies that use the average duration of transmission line outages in their calculations. It was concluded that the new methodology can be applied to any transmission line system operating in a unique geographical environmental area. 11 refs., 3 tabs., 5 figs.

  4. Statistical Evolution of the Lightning Flash

    Science.gov (United States)

    Zoghzoghy, F. G.; Cohen, M.; Said, R.; Inan, U. S.

    2012-12-01

    Natural lightning is one of the most fascinating and powerful electrical processes on Earth. To date, the physics behind this natural phenomenon are not fully understood, due primarily to the difficulty of obtaining measurements inside thunderstorms and to the wide range of timescales involved (from nanoseconds to seconds). Our aim is to use accurate lightning geo-location data from the National Lightning Detection Network (NLDN) to study statistical patterns in lightning, taking advantage of the fact that millions of lightning flashes occur around the globe every day. We present two sets of results, one involving the patterns of flashes in a storm, and a second involving the patterns of strokes in a flash. These patterns can provide a surrogate measure of the timescales and the spatial extents of the underlying physical processes. First, we study the timescales of charge buildup inside thunderstorms. We find that, following a lightning flash, the probability of another neighboring flash decreases and takes tens of seconds to recover. We find that this suppression effect is a function of flash type, stroke peak current, cloud-to-ground (CG) stroke multiplicity, and other lightning and geographical parameters. We find that the probabilities of subsequent flashes are more suppressed following oceanic lightning, or following flashes with higher peak currents and/or higher multiplicities (for CG flashes). Second, we use NLDN data to study the evolution of the strokes within a CG flash. A CG flash typically includes multiple return strokes, which can occur in the same channel or in multiple channels within a few kilometers. We cluster NLDN stroke data into flashes and produce the probability density function of subsequent strokes as a function of distance and time-delays relative to the previous stroke. Using this technique, we investigate processes which occur during the CG lightning flash with nanosecond to millisecond timescales. For instance, our results suggest

  5. Classification of Small Negative Lightning Reports at the KSC-ER

    Science.gov (United States)

    Ward, Jennifer G.; Cummins, Kenneth L.; Krider, Philip

    2008-01-01

    The NASA Kennedy Space Center (KSC) and Air Force Eastern Range (ER) operate an extensive suite of lightning sensors because Florida experiences the highest area density of ground strikes in the United States, with area densities approaching 16 fl/sq km/yr when accumulated in 10x10 km (100 sq km) grids. The KSC-ER use data derived from two cloud-to-ground (CG) lightning detection networks, the "Cloud-to-Ground Lightning Surveillance System" (CGLSS) and the U.S. National Lightning Detection Network (TradeMark) (NLDN) plus a 3-dimensional lightning mapping system, the Lightning Detection and Ranging (LDAR) system, to provide warnings for ground operations and to insure mission safety during space launches. For operational applications at the KSC-ER it is important to understand the performance of each lightning detection system in considerable detail. In this work we examine a specific subset of the CGLSS stroke reports that have low values of the negative inferred peak current, Ip, i.e. values between 0 and -7 kA, and were thought to produce a new ground contact (NGC). When possible, the NLDN and LDAR systems were used to validate the CGLSS classification and to determine how many of these reported strokes were first strokes, subsequent strokes in a pre-existing channel (PEC), or cloud pulses that the CGLSS misclassified as CG strokes. It is scientifically important to determine the smallest current that can reach the ground either in the form of a first stroke or by way of a subsequent stroke that creates a new ground contact. In Biagi et al (2007), 52 low amplitude, negative return strokes ([Ip] strokes) on the basis of video and waveform recordings. Low amplitude return strokes are interesting because they are usually difficult to detect, and they are thought to bypass conventional lightning protection that relies on a sufficient attractive radius to prevent "shielding failure" (Golde, 1977). They also have larger location errors compared to the larger current

  6. Climate Change and Tropical Total Lightning

    Science.gov (United States)

    Albrecht, R.; Petersen, W.; Buechler, D.; Goodman, S.; Blakeslee, R.; Christian, H.

    2009-01-01

    While global warming is regarded as a fact by many in the scientific community, its future impact remains a challenge to be determined and measured. The International Panel on Climate Change (IPCC) assessment report (IPCC, 2007) shows inconclusive answers on global rainfall trends and general agreement on a future drier climate with increased global warming. The relationship between temperature, humidity and convection is not linear and is strongly dependent on regional scale features, such as topography and land cover. Furthermore, the relationship between convective lightning production (thunderstorms) and temperature is even more complicated, being subjected to the cloud dynamics and microphysics. Total lightning (intracloud and cloud-to-ground) monitoring is a relatively new field of observation. Global and tropical total lightning began to be more extensively measured by satellites in the mid 90s. In this scope, the Lightning Imaging Sensor (LIS) onboard of the Tropical Rainfall Measurement Mission (TRMM) has been operational for over 11 years. Here we address total lightning trends observed by LIS from 1998 to 2008 in different temporal (annual and seasonal) and spatial (large and regional) scales. The observed 11-year trends are then associate to different predicted/hypothesized climate change scenarios.

  7. Lightning flash sizes relative to storm structure and turbulence during the Kinematic Texture and Lightning Experiment

    Science.gov (United States)

    Bruning, E. C.; Salinas, V.; Berkseth, S.; Chmielewski, V.; Brothers, M.

    2016-12-01

    Ongoing work as part of the Kinematic Texture and Lightning Experiment at Texas Tech University has quantified the lightning flash size, rate, and energy alongside the turbulent structure of thunderclouds. 2016 was the final year of observations, which fielded two high-resolution mobile Ka-band radars and mobile environmental soundings. Lightning measurements were made by a VHF Lightning Mapping Array. In order to enhance the detection of the smallest lightning discharges in the turbulent portions of the thundercloud, a rapidly-deployable mobile Lightning Mapping Array (LMA) station augmented a traditional fixed LMA. This capability of targeting particular storm complexes with LMA measurements will be described, and the improved detection capability quantified. The complete set of field measurements from 2014-16 sampled numerous individual cells and storm complexes, ranging in intensity from multicellular convection to supercells and mesoscale convective systems. Flash measurements coincident with radar observations included deep, highly turbulent convective cores and extensive anvil regions. Comparison of flash characteristics across these storm morphologies will be shown, with a focus on the dynamical organization of storms and the turbulent kinematics that drive differences in lightning flash sizes and rates.

  8. Precision Departure Release Capability (PDRC): NASA to FAA Research Transition

    Science.gov (United States)

    Engelland, Shawn; Davis, Thomas J.

    2013-01-01

    departure runway assignments to the Center scheduling tool. The PDRC concept also incorporates earlier NASA and FAA research into automation-assisted CFR coordination. The PDRC concept reduces uncertainty by automatically communicating coordinated release times with seconds-level precision enabling TMCs and FLMs to work with target times rather than windows. NASA has developed a PDRC prototype system that integrates the Center's TMA system with a research prototype Tower decision support tool. A two-phase field evaluation was conducted at NASA's North Texas Research Station in Dallas-Fort Worth. The field evaluation validated the PDRC concept and demonstrated reduced release time uncertainty while being used for tactical departure scheduling of more than 230 operational flights over 29 weeks of operations.

  9. Objective Lightning Probability Forecast Tool Phase II

    Science.gov (United States)

    Lambert, Winnie

    2007-01-01

    This presentation describes the improvement of a set of lightning probability forecast equations that are used by the 45th Weather Squadron forecasters for their daily 1100 UTC (0700 EDT) weather briefing during the warm season months of May-September. This information is used for general scheduling of operations at Cape Canaveral Air Force Station and Kennedy Space Center. Forecasters at the Spaceflight Meteorology Group also make thunderstorm forecasts during Shuttle flight operations. Five modifications were made by the Applied Meteorology Unit: increased the period of record from 15 to 17 years, changed the method of calculating the flow regime of the day, calculated a new optimal layer relative humidity, used a new smoothing technique for the daily climatology, and used a new valid area. The test results indicated that the modified equations showed and increase in skill over the current equations, good reliability, and an ability to distinguish between lightning and non-lightning days.

  10. Lightning and severe thunderstorms in event management.

    Science.gov (United States)

    Walsh, Katie M

    2012-01-01

    There are a few national position stands/guidelines that address environmental conditions in athletics, yet they do not govern all outdoor sports. Extreme heat and cold, lightning, and severe wind can all be fatal, yet the majority of outdoor sports have no published guidelines addressing these conditions in relation to activity. Available research on extreme heat and cold conditions in athletics provides prevention strategies, to include acclimatization. Lightning and severe wind are two environmental conditions to which humans cannot accommodate, and they both can be deadly. There are strong positions on extreme heat/cold and lightning safety in athletics, but none affiliated with severe winds. Medical personnel involved in planning large outdoor sporting events must know of the presence of nationally published weather-related documents and apply them to their event. In addition, research needs to be expanded in the realm of establishing guidelines for safety to participants and spectators in severe wind conditions.

  11. On ULF Signatures of Lightning Discharges

    Science.gov (United States)

    Bösinger, T.; Shalimov, S. L.

    2008-06-01

    Recent works on magnetic signatures due to distant lightning discharges are reviewed. Emphasis is laid on magnetic signatures in the ULF range (in the old definition from less than 1 mHz up to 1 Hz), that is in the frequency range below the Schumann resonance. These signatures are known to be of importance for the excitation of the ionospheric Alfvén resonator (IAR) which works only at night time conditions. This emphasizes the difference between night and day time ULF signatures of lightning. The IAR forms a link between the atmosphere and magnetosphere. Similarities and differences of this link in the VLF (Trimpi effect) and ULF range are worked out. A search for a unique signature of sprite-associated positive cloud-to-ground (+CG) lightning discharges ended with a negative result. In this context, however, a new model of lightning-associated induced mesospheric currents was built. Depending on mesospheric condition it can produce magnetic signatures in the entire frequency range from VLF, ELF to ULF. In the latter case it can explain signatures known as the Ultra Slow Tail of +CG lightning discharges. A current problem on the magnetic background noise intensity has been solved by taking more seriously the contribution of +CG lightning discharges to the overall background noise. Their low occurrence rate is more than compensated by their large and long lasting continuing currents. By superposed epoch analysis it could be shown that the ULF response to -CG is one to two orders smaller that in case of +CG with similar peak current values of the return stroke.

  12. Artificial Neural Network applied to lightning flashes

    Science.gov (United States)

    Gin, R. B.; Guedes, D.; Bianchi, R.

    2013-05-01

    The development of video cameras enabled cientists to study lightning discharges comportment with more precision. The main goal of this project is to create a system able to detect images of lightning discharges stored in videos and classify them using an Artificial Neural Network (ANN)using C Language and OpenCV libraries. The developed system, can be split in two different modules: detection module and classification module. The detection module uses OpenCV`s computer vision libraries and image processing techniques to detect if there are significant differences between frames in a sequence, indicating that something, still not classified, occurred. Whenever there is a significant difference between two consecutive frames, two main algorithms are used to analyze the frame image: brightness and shape algorithms. These algorithms detect both shape and brightness of the event, removing irrelevant events like birds, as well as detecting the relevant events exact position, allowing the system to track it over time. The classification module uses a neural network to classify the relevant events as horizontal or vertical lightning, save the event`s images and calculates his number of discharges. The Neural Network was implemented using the backpropagation algorithm, and was trained with 42 training images , containing 57 lightning events (one image can have more than one lightning). TheANN was tested with one to five hidden layers, with up to 50 neurons each. The best configuration achieved a success rate of 95%, with one layer containing 20 neurons (33 test images with 42 events were used in this phase). This configuration was implemented in the developed system to analyze 20 video files, containing 63 lightning discharges previously manually detected. Results showed that all the lightning discharges were detected, many irrelevant events were unconsidered, and the event's number of discharges was correctly computed. The neural network used in this project achieved a

  13. Visual Analysis for Nowcasting of Multidimensional Lightning Data

    Directory of Open Access Journals (Sweden)

    Stefan Peters

    2013-08-01

    Full Text Available Globally, most weather-related damages are caused by thunderstorms. Besides floods, strong wind, and hail, one of the major thunderstorm ground effects is lightning. Therefore, lightning investigations, including detection, cluster identification, tracking, and nowcasting are essential. To enable reliable decisions, current and predicted lightning cluster- and track features as well as analysis results have to be represented in the most appropriate way. Our paper introduces a framework which includes identification, tracking, nowcasting, and in particular visualization and statistical analysis of dynamic lightning data in three-dimensional space. The paper is specifically focused on enabling users to conduct the visual analysis of lightning data for the purpose of identification and interpretation of spatial-temporal patterns embedded in lightning data, and their dynamics. A graphic user interface (GUI is developed, wherein lightning tracks and predicted lightning clusters, including their prediction certainty, can be investigated within a 3D view or within a Space-Time-Cube. In contrast to previous work, our approach provides insight into the dynamics of past and predicted 3D lightning clusters and cluster features over time. We conclude that an interactive visual exploration in combination with a statistical analysis can provide new knowledge within lightning investigations and, thus, support decision-making in weather forecast or lightning damage prevention.

  14. The lightning activities in super typhoons over the Northwest Pacific

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The spatial and temporal characteristics of lightning activities have been studied in seven super typhoons from 2005 to 2008 over the Northwest Pacific, using data from the World Wide Lightning Location Network (WWLLN). The results indicated that there were three distinct lightning flash regions in mature typhoon, a significant maximum in the eyewall regions (20-80 km from the center), a minimum from 80-200 km, and a strong maximum in the outer rainbands (out of 200 km from the center). The lightning flashes in the outer rainbands were much more than those in the inner rainbands, and less than 1% of flashes occurred within 100 km of the center. Each typhoon produced eyewall lightning outbreak during the periods of its intensification, usually several hours prior to its maximum intensity, indicating that lightning activity might be used as a proxy of intensification of super typhoon. Little lightning occurred near the center after landing of the typhoon.

  15. Irregularities of ionospheric VTEC during lightning activity over Antarctic Peninsula

    Science.gov (United States)

    Suparta, W.; Nor, W. N. A. Wan Mohd

    2017-05-01

    This paper investigates the irregularities of vertical total electron content (VTEC) during lightning activity and geomagnetic quiet days over Antarctic Peninsula in year 2014. During the lightning event, the ionosphere may be disturbed which may cause disruption in the radio signal. Thus, it is important to understand the influence of lightning on VTEC in the study of upper-lower interaction. The lightning data is obtained from World Wide Lightning Location Network (WWLLN) and the VTEC data has analyzed from Global Positioning System (GPS) for O’Higgins (OHI3), Palmer (PALV), and Rothera (ROTH). The results demonstrate the VTEC variation of ∼0.2 TECU during low lightning activity which could be caused by energy dissipation through lightning discharges from troposphere into the thermosphere.

  16. 78 FR 71706 - Advisory Committee for Aviation Consumer Protection

    Science.gov (United States)

    2013-11-29

    ... mandated by Section 411 of the FAA Modernization and Reform Act of 2012 (Pub. L. 112-95, 126 Stat. 11 (2012... passengers arriving on international flights through the U.S. Customs and Border Protection facilities at...

  17. Lightning Surge Analysis in 154 kV S/S due to Flashover on the 4 Circuits Tower

    Energy Technology Data Exchange (ETDEWEB)

    Woo, J. W.; Shim, E. B.; Kwak, J. S.; Choi, B. J. [Korea Electric Power Corporation (Korea)

    2000-07-01

    This paper describes the analysis results for the protection of lightning surge at 154 kV substation. We found that the surge arrester is needed at the inlet structure. The maximum overvoltage is about 1,500 kV at the circuit breaker without the surge arrester at the inlet structure. This value can be lower than 600 kV by installing the surge arrester at the inlet structure. In addition to the shield wire should be considered to prevent the shielding failure by the direct lightning stroke. (author). 6 refs., 8 figs.

  18. The verification of lightning location accuracy in Finland deduced from lightning strikes to trees

    Science.gov (United States)

    Mäkelä, Antti; Mäkelä, Jakke; Haapalainen, Jussi; Porjo, Niko

    2016-05-01

    We present a new method to determine the ground truth and accuracy of lightning location systems (LLS), using natural lightning strikes to trees. Observations of strikes to trees are being collected with a Web-based survey tool at the Finnish Meteorological Institute. Since the Finnish thunderstorms tend to have on average a low flash rate, it is often possible to identify from the LLS data unambiguously the stroke that caused damage to a given tree. The coordinates of the tree are then the ground truth for that stroke. The technique has clear advantages over other methods used to determine the ground truth. Instrumented towers and rocket launches measure upward-propagating lightning. Video and audio records, even with triangulation, are rarely capable of high accuracy. We present data for 36 quality-controlled tree strikes in the years 2007-2008. We show that the average inaccuracy of the lightning location network for that period was 600 m. In addition, we show that the 50% confidence ellipse calculated by the lightning location network and used operationally for describing the location accuracy is physically meaningful: half of all the strikes were located within the uncertainty ellipse of the nearest recorded stroke. Using tree strike data thus allows not only the accuracy of the LLS to be estimated but also the reliability of the uncertainty ellipse. To our knowledge, this method has not been attempted before for natural lightning.

  19. The influence of lightning induced voltage on the distribution power line polymer insulators

    Science.gov (United States)

    Ab-Kadir, Mohd Zainal Abidin; Gomes, Chandima; Jasni, Jasronita; Hajikhani, Maryam

    2017-01-01

    Protection of medium voltage (MV) overhead lines against the indirect effects of lightning is an important issue in Malaysia and other tropical countries. Protection of these lines against the indirect effects of lightning is a major concern and can be improved by several ways. The choice of insulator to be used for instance, between the glass, ceramic or polymer, can help to improve the line performance from the perspective of increasing the breakdown strength. In this paper, the electrical performance of a 10 kV polymer insulator under different conditions for impulse, weather and insulator angle with respect to a cross-arm were studied (both experimental and modelling) and the results were discussed accordingly. Results show that the weather and insulator angle (with respect to the cross-arm) are surprisingly influenced the values of breakdown voltage and leakage current for both negative and positive impulses. Therefore, in order to select a proper protection system for MV lines against lightning induced voltage, consideration of the local information concerning the weather and also the insulator angles with respect to the cross-arm are very useful for line stability and performance. PMID:28234930

  20. The influence of lightning induced voltage on the distribution power line polymer insulators.

    Science.gov (United States)

    Izadi, Mahdi; Abd Rahman, Muhammad Syahmi; Ab-Kadir, Mohd Zainal Abidin; Gomes, Chandima; Jasni, Jasronita; Hajikhani, Maryam

    2017-01-01

    Protection of medium voltage (MV) overhead lines against the indirect effects of lightning is an important issue in Malaysia and other tropical countries. Protection of these lines against the indirect effects of lightning is a major concern and can be improved by several ways. The choice of insulator to be used for instance, between the glass, ceramic or polymer, can help to improve the line performance from the perspective of increasing the breakdown strength. In this paper, the electrical performance of a 10 kV polymer insulator under different conditions for impulse, weather and insulator angle with respect to a cross-arm were studied (both experimental and modelling) and the results were discussed accordingly. Results show that the weather and insulator angle (with respect to the cross-arm) are surprisingly influenced the values of breakdown voltage and leakage current for both negative and positive impulses. Therefore, in order to select a proper protection system for MV lines against lightning induced voltage, consideration of the local information concerning the weather and also the insulator angles with respect to the cross-arm are very useful for line stability and performance.

  1. Lightning Pin Injection Testing on MOSFETS

    Science.gov (United States)

    Ely, Jay J.; Nguyen, Truong X.; Szatkowski, George N.; Koppen, Sandra V.; Mielnik, John J.; Vaughan, Roger K.; Wysocki, Philip F.; Celaya, Jose R.; Saha, Sankalita

    2009-01-01

    Lightning transients were pin-injected into metal-oxide-semiconductor field-effect transistors (MOSFETs) to induce fault modes. This report documents the test process and results, and provides a basis for subsequent lightning tests. MOSFETs may be present in DC-DC power supplies and electromechanical actuator circuits that may be used on board aircraft. Results show that unprotected MOSFET Gates are susceptible to failure, even when installed in systems in well-shielded and partial-shielded locations. MOSFET Drains and Sources are significantly less susceptible. Device impedance decreased (current increased) after every failure. Such a failure mode may lead to cascading failures, as the damaged MOSFET may allow excessive current to flow through other circuitry. Preliminary assessments on a MOSFET subjected to 20-stroke pin-injection testing demonstrate that Breakdown Voltage, Leakage Current and Threshold Voltage characteristics show damage, while the device continues to meet manufacturer performance specifications. The purpose of this research is to develop validated tools, technologies, and techniques for automated detection, diagnosis and prognosis that enable mitigation of adverse events during flight, such as from lightning transients; and to understand the interplay between lightning-induced surges and aging (i.e. humidity, vibration thermal stress, etc.) on component degradation.

  2. Lightning driven EMP in the upper atmosphere

    Science.gov (United States)

    Rowland, H. L.; Fernsler, R. F.; Huba, J. D.; Bernhardt, P. A.

    1995-01-01

    Large lightning discharges can drive electromagnetic pulses (EMP) that cause breakdown of the neutral atmosphere between 80 and 95 km leading to order of magnitude increases in the plasma density. The increase in the plasma density leads to increased reflection and absorption, and limits the pulse strength that propagates higher into the ionosphere.

  3. 14 CFR 35.38 - Lightning strike.

    Science.gov (United States)

    2010-01-01

    ... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: PROPELLERS Tests and Inspections § 35.38 Lightning strike. The applicant must demonstrate, by tests, analysis based on tests, or experience on similar designs, that the propeller can withstand...

  4. Lightning detection and exposure algorithms for smartphones

    Science.gov (United States)

    Wang, Haixin; Shao, Xiaopeng; Wang, Lin; Su, Laili; Huang, Yining

    2015-05-01

    This study focuses on the key theory of lightning detection, exposure and the experiments. Firstly, the algorithm based on differential operation between two adjacent frames is selected to remove the lightning background information and extract lighting signal, and the threshold detection algorithm is applied to achieve the purpose of precise detection of lightning. Secondly, an algorithm is proposed to obtain scene exposure value, which can automatically detect external illumination status. Subsequently, a look-up table could be built on the basis of the relationships between the exposure value and average image brightness to achieve rapid automatic exposure. Finally, based on a USB 3.0 industrial camera including a CMOS imaging sensor, a set of hardware test platform is established and experiments are carried out on this platform to verify the performances of the proposed algorithms. The algorithms can effectively and fast capture clear lightning pictures such as special nighttime scenes, which will provide beneficial supporting to the smartphone industry, since the current exposure methods in smartphones often lost capture or induce overexposed or underexposed pictures.

  5. 基于雷电定位系统与行波实测数据的雷击故障关联度分析%The Correlation Degree of Lightning Location System and Measured Field Traveling Wave Data for Lightning Induced Fault Distinguishing

    Institute of Scientific and Technical Information of China (English)

    曹璞璘; 束洪春; 马仪; 黄然; 董俊; 余多; 白冰

    2015-01-01

    The identification of lightning induced fault and fault without lightning striking is a significant factor for lightning protection design to reduce number of lightning induced fault. In order to analyze the possibility of the information fusion of lightning location system (LLS) record and traveling wave data, this paper dissected different time and space domain characteristic of these two systems records. Considered the height difference influence, the fault distance calculated by traveling wave was transformed to suspected fault tower to calculating the difference between lightning records and traveling wave data. The polarity of traveling wave and lightning current was taken into account to remove some lightning records with different polarity. For computing the correlation degree of lightning records and traveling wave data, the number of detection station demonstrated the accuracy of lightning records is considered. The lightning induced fault and fault without lightning is identified based on the incidence of lightning records and traveling wave data. The proposed method was confirmed by the line patrolling results.%准确识别雷击故障与非雷击性故障对针对化防雷设计、降低雷击跳闸率具有重要意义.从雷电定位系统记录与行波数据所包含时空信息的不同特点入手,分析雷电地闪记录与行波数据在时间与空间上的关联可能性,计及高程差对线路长度影响,将行波测距结果换算为故障参考杆塔坐标,使行波测距结果能够与雷电地闪记录位置进行空间层面的匹配.引入雷电流极性与初始行波极性排除部分极性不一致的雷电地闪记录干扰,以地闪观测站数作为必要的附加条件,构造雷击记录与行波数据之间的关联度函数,对具体一次实际故障是否为雷击故障计算出关联度,在此基础上对雷击故障与非雷击性故障进行判断.并以实际巡线结果为依据,验证了所提算法的可行性.

  6. Acute transient hemiparesis induced by lightning strike.

    Science.gov (United States)

    Rahmani, Seyed Hesam; Faridaalaee, Gholamreza; Jahangard, Samira

    2015-07-01

    According to data from the National Oceanic and Atmospheric Administration,in the years from 1959 to 1994, lightning was responsible for more than 3000 deaths and nearly 10,000 casualties. The most important characteristic features of lightning injuries are multisystem involvement and widely variable severity. Lightning strikes are primarily a neurologic injury that affects all 3 components of the nervous system: central, autonomic,and peripheral. Neurologic complications of lightning strikes vary from transient benign symptoms to permanent disability. Many patients experience a temporary paralysis called keraunoparalysis. Here we reported a 22-year-old mountaineer man with complaining of left sided hemiparesis after being hit by a lightning strike in the mountain 3 hours ago. There was no loss of consciousness at hitting time. On arrival the patient was alert, awake and hemodynamically stable. In neurologic examination cranial nerves were intact, left sided upper and lower extremity muscle force was I/V with a combination of complete sensory loss, and right-sided muscle force and sensory examination were normal. There is not any evidence of significant vascular impairment in the affected extremities. Brain MRI and CT scan and cervical MRI were normal. During 2 days of admission, with intravenous hydration, heparin 5000 unit SC q12hr and physical therapy of the affected limbs, motor and sensory function improved and was normal except mild paresthesia. He was discharged 1 day later for outpatient follow up while vitamin B1 100mg orally was prescribed.Paresthesia improved after 3 days without further sequels.

  7. Ionospheric effects of whistler waves from rocket-triggered lightning

    Science.gov (United States)

    Cotts, B. R. T.; Gołkowski, M.; Moore, R. C.

    2011-12-01

    Lightning-induced electron precipitation (LEP) is one of the primary mechanisms for energetic electron loss from Earth's radiation belts. While previous works have emphasized lightning location and the return stroke peak current in quantifying lightning's role in radiation belt electron loss, the spectrum of the lightning return stroke has received far less attention. Rocket-triggered lightning experiments performed at the International Center for Lightning Research and Testing (ICLRT) at Camp Blanding, Florida, provide a means to directly measure the spectral content of individual lightning return strokes. Using an integrated set of numerical models and directly observed rocket-triggered lightning channel-base currents we calculate the latitudinal dependence of the precipitation signature. Model results indicate that rocket-triggered lightning may produce detectable LEP events and that return strokes with higher ELF (3 Hz-3 kHz) content cause proportionally more ionospheric ionization and precipitate more electrons at higher latitudes than return strokes with proportionally higher VLF (3 kHz-30 kHz) content. The predicted spatio-temporal signature of the induced electron precipitation is highly dependent upon the return stroke spectral content. As a result, we postulate that rocket-triggered lightning experiments enable us to the estimate the spectral profile of energetic electrons precipitated from the Earth's radiation belts.

  8. Lightning Sensors for Observing, Tracking and Nowcasting Severe Weather

    Science.gov (United States)

    Price, Colin

    2008-01-01

    Severe and extreme weather is a major natural hazard all over the world, often resulting in major natural disasters such as hail storms, tornados, wind storms, flash floods, forest fires and lightning damages. While precipitation, wind, hail, tornados, turbulence, etc. can only be observed at close distances, lightning activity in these damaging storms can be monitored at all spatial scales, from local (using very high frequency [VHF] sensors), to regional (using very low frequency [VLF] sensors), and even global scales (using extremely low frequency [ELF] sensors). Using sensors that detect the radio waves emitted by each lightning discharge, it is now possible to observe and track continuously distant thunderstorms using ground networks of sensors. In addition to the number of lightning discharges, these sensors can also provide information on lightning characteristics such as the ratio between intra-cloud and cloud-to-ground lightning, the polarity of the lightning discharge, peak currents, charge removal, etc. It has been shown that changes in some of these lightning characteristics during thunderstorms are often related to changes in the severity of the storms. In this paper different lightning observing systems are described, and a few examples are provided showing how lightning may be used to monitor storm hazards around the globe, while also providing the possibility of supplying short term forecasts, called nowcasting. PMID:27879700

  9. A qualitative phenomenological study: Enhanced, risk-based FAA oversight on part 145 maintenance practices

    Science.gov (United States)

    Sheehan, Bryan G.

    The purpose of this qualitative phenomenological study was to examine the phenomenon of enhanced, risk-based Federal Aviation Administration (FAA) oversight of Part 145 repair stations that performed aircraft maintenance for Part 121 air carriers between 2007 and 2014 in Oklahoma. Specifically, this research was utilized to explore what operational changes have occurred in the domestic Part 145 repair station industry such as variations in management or hiring practices, training, recordkeeping and technical data, inventory and aircraft parts supply-chain logistics, equipment, and facilities. After interviewing 12 managers from Part 145 repair stations in Oklahoma, six major theme codes emerged from the data: quality of oversight before 2007, quality of oversight after 2007, advantages of oversight, disadvantages of oversight, status quo of oversight, and process improvement . Of those six major theme codes, 17 subthemes appeared from the data that were used to explain the phenomenon of enhanced oversight in the Part 145 repair station industry. Forty-two percent of the participants indicated a weak FAA oversight system that has hindered the continuous process improvement program in their repair stations. Some of them were financially burdened after hiring additional full-time quality assurance inspectors to specifically manage enhanced FAA oversight. Notwithstanding, the participants of the study indicated that the FAA must apply its surveillance on a more standardized and consistent basis. They want to see this standardization in how FAA inspectors interpret regulations and practice the same quality of oversight for all repair stations, particularly those that are repeat violators and fail to comply with federal aviation regulations. They believed that when the FAA enforces standardization on a consistent basis, repair stations can become more efficient and safer in the performance of their scope of work for the U.S. commercial air transportation industry.

  10. Electric Field Change and VHF Radiation during Lightning Initiation

    Science.gov (United States)

    Marshall, T. C.; Karunarathne, S.; Bandara, S. A.; Karunarathne, N. D.; Siedlecki, R.; Stolzenburg, M.

    2016-12-01

    Recent studies of lightning initiation [e.g., Marshall et al., JGR 2014; Marshall et al., AGU 2015] have shown that an initial electric field change (IEC) occurs for about 1 ms before the first initial breakdown (IB) pulse in most (and perhaps all) lightning flashes. The same studies indicate that the IEC itself begins after an event that radiates strongly in the VHF radio band; this event seems to be the real lightning initiation event [e.g., Rison et al., Nature Communications 2016]. During the summer of 2016 we used an array of E-change sensors and VHF sensors located in north Mississippi to obtain correlated data on the VHF lightning initiation event, the IEC, and the IB pulses of nearby lightning flashes. In this presentation we show examples of lightning initiation events and their subsequent IECs at multiple sensors. In addition, we show examples of the VHF radiation associated with IB pulses.

  11. Weekly Cycle of Lightning: Evidence of Storm Invigoration by Pollution

    Science.gov (United States)

    Bell, Thomas L.; Rosenfeld, Daniel; Kim, Kyu-Myong

    2009-01-01

    We have examined summertime 1998 2009 U.S. lightning data from the National Lightning Detection Network (NLDN) to look for weekly cycles in lightning activity. As was found by Bell et al. (2008) for rain over the southeast U.S., there is a significant weekly cycle in afternoon lightning activity that peaks in the middle of the week there. The weekly cycle appears to be reduced over population centers. Lightning activity peaks on weekends over waters near the SE U.S. The statistical significance of weekly cycles over the western half of the country is generally small. We found no evidence of a weekly cycle of synoptic-scale forcing that might explain these patterns. The lightning behavior is entirely consistent with the explanation suggested by Bell et al. (2008) for the cycles in rainfall and other atmospheric data from the SE U.S., that aerosols can cause storms to intensify in humid, convectively unstable environments.

  12. Chasing Lightning: Sferics, Tweeks and Whistlers

    Science.gov (United States)

    Webb, P. A.; Franzen, K.; Garcia, L.; Schou, P.; Rous, P.

    2008-12-01

    We all know what lightning looks like during a thunderstorm, but the visible flash we see is only part of the story. This is because lightning also generates light with other frequencies that we cannot perceive with our eyes, but which are just as real as visible light. Unlike the visible light from lightning, these other frequencies can carry the lightning's energy hundreds or thousands of miles across the surface of the Earth in the form of special signals called "tweeks" and "sferics". Some of these emissions can even travel tens of thousands of miles out into space before returning to the Earth as "whistlers". The INSPIRE Project, Inc is a non-profit scientific and educational corporation whose beginning mission was to bring the excitement of observing these very low frequency (VLF) natural radio waves emissions from lightning to high school students. Since 1989, INSPIRE has provided specially designed radio receiver kits to over 2,600 participants around the world to make observations of signals in the VLF frequency range. Many of these participants are using the VLF data they collect in very creative projects that include fiction, music and art exhibitions. During the Fall 2008 semester, the first INSPIRE based university-level course was taught at University of Maryland Baltimore County (UMBC) as part of its First-Year Seminar (FYS) series. The FYS classes are limited to 20 first-year students per class and are designed to create an active-learning environment that encourages student participation and discussion that might not otherwise occur in larger first-year classes. This presentation will cover the experiences gained from using the INSPIRE kits as the basis of a university course. This will include the lecture material that covers the basic physics of lightning, thunderstorms and the Earth's atmosphere, as well as the electronics required to understand the basic workings of the VLF kit. It will also cover the students assembly of the kit in an

  13. The impact of lightning on tropospheric ozone chemistry using a new global lightning parametrisation

    Science.gov (United States)

    Finney, D. L.; Doherty, R. M.; Wild, O.; Abraham, N. L.

    2016-06-01

    A lightning parametrisation based on upward cloud ice flux is implemented in a chemistry-climate model (CCM) for the first time. The UK Chemistry and Aerosols model is used to study the impact of these lightning nitric oxide (NO) emissions on ozone. Comparisons are then made between the new ice flux parametrisation and the commonly used, cloud-top height parametrisation. The ice flux approach improves the simulation of lightning and the temporal correlations with ozone sonde measurements in the middle and upper troposphere. Peak values of ozone in these regions are attributed to high lightning NO emissions. The ice flux approach reduces the overestimation of tropical lightning apparent in this CCM when using the cloud-top approach. This results in less NO emission in the tropical upper troposphere and more in the extratropics when using the ice flux scheme. In the tropical upper troposphere the reduction in ozone concentration is around 5-10 %. Surprisingly, there is only a small reduction in tropospheric ozone burden when using the ice flux approach. The greatest absolute change in ozone burden is found in the lower stratosphere, suggesting that much of the ozone produced in the upper troposphere is transported to higher altitudes. Major differences in the frequency distribution of flash rates for the two approaches are found. The cloud-top height scheme has lower maximum flash rates and more mid-range flash rates than the ice flux scheme. The initial Ox (odd oxygen species) production associated with the frequency distribution of continental lightning is analysed to show that higher flash rates are less efficient at producing Ox; low flash rates initially produce around 10 times more Ox per flash than high-end flash rates. We find that the newly implemented lightning scheme performs favourably compared to the cloud-top scheme with respect to simulation of lightning and tropospheric ozone. This alternative lightning scheme shows spatial and temporal differences in

  14. Total Lightning Characteristics and Electric Structure Evolution in a Hailstorm

    Institute of Scientific and Technical Information of China (English)

    ZHENG Dong; ZHANG Yijun; MENG Qing; LU Weitao; YI Xiaoyuan

    2009-01-01

    In this paper, total lightning data observed by SAFIR3000 3-D Lightning Locating System was combined with radar data to analyze characteristics of the lightning activity and electric structure of a hailstorm that occurred in Beijing on 31 May 2005. The results indicated that there were two active periods for the lightning activity during the hailstorm process. The hail shooting was found in the first period. After the end of the hail shooting, lightning frequency decreased suddenly. However, more active lightning activities occurred in the second period with lots of them appearing in the cloud anvil region. The peak of the lightning frequency came about 5 rain prior to the hail shooting. Only 6.16% of the total lightning was cloud-to-ground (CG) lightning, among which 20% had positive polarity. This percentage was higher than that in normal thunderstorms. In addition, heavier positive CG lightning discharge occurred before rather than after the hail shooting. In the stage of the hail shooting, the electric structure of the hailstorm was inverted, with the main negative charge region located around the -40℃ level and the main positive charge region around the -15℃ level. In addition, a weak negative charge region existed below the positive charge region transitorily. After the hail shooting, the electric structure underwent fast and persistent adjustments and became a normal tripole, with positive charge in the upper and lower levels and negative charge in the middle levels. However, the electric structure was tilted under the influence of the westerly wind in the middle and upper levels. The lightning activity and electric structure were closely related to the dynamic and microphysical processes of the hailstorm. It was believed that severe storms with stronger updrafts were more conducive to an inverted tripolar electric structure than normal thunderstorms, and the inverted distribution could then facilitate more positive CG lightning in the severe storms.

  15. OBSERVATIONAL STUDY OF LIGHTNING CHARACTERISTICS IN HAIL-PRODUCING CLOUDS

    Institute of Scientific and Technical Information of China (English)

    LI Zhao-rong; FU Shuang-xi; LI Bao-zi; JIANG Lin

    2006-01-01

    @@ 1 INTRODUCTION Lightning is a phenomenon of atmospheric electricity with convective storms. Since the 1960's, its characteristics during weather processes of torrential rain, hails and tornadoes have been widely studied and a lot of attempts made to probe into the mechanisms responsible for the formation of lightning[1], giving rise to two theories explaining the lightning genesis, from the points of convection and ice-phase precipitation,respectively.

  16. New method for lightning location using optical ground wire

    Institute of Scientific and Technical Information of China (English)

    Zhaoyu Qin; Zhaogu Cheng; Zhiping Zhang; Jianqiang Zhu; Feng Li

    2006-01-01

    A new technology of lightning location is described, which is based on detecting the state of polarization(SOP) fluctuation of the laser light in the optic ground wire (OPGW). Compared with the conventional lightning location method, the new method is more accurate, more stable, and cheaper. Theories of Stokes generated by lightning strike can still be accurately identified by detecting the velocity of polarization motion. A new algorithm to quantify the velocity is also introduced.

  17. Lightning Radio Source Retrieval Using Advanced Lightning Direction Finder (ALDF) Networks

    Science.gov (United States)

    Koshak, William J.; Blakeslee, Richard J.; Bailey, J. C.

    1998-01-01

    A linear algebraic solution is provided for the problem of retrieving the location and time of occurrence of lightning ground strikes from an Advanced Lightning Direction Finder (ALDF) network. The ALDF network measures field strength, magnetic bearing and arrival time of lightning radio emissions. Solutions for the plane (i.e., no Earth curvature) are provided that implement all of tile measurements mentioned above. Tests of the retrieval method are provided using computer-simulated data sets. We also introduce a quadratic planar solution that is useful when only three arrival time measurements are available. The algebra of the quadratic root results are examined in detail to clarify what portions of the analysis region lead to fundamental ambiguities in source location. Complex root results are shown to be associated with the presence of measurement errors when the lightning source lies near an outer sensor baseline of the ALDF network. In the absence of measurement errors, quadratic root degeneracy (no source location ambiguity) is shown to exist exactly on the outer sensor baselines for arbitrary non-collinear network geometries. The accuracy of the quadratic planar method is tested with computer generated data sets. The results are generally better than those obtained from the three station linear planar method when bearing errors are about 2 deg. We also note some of the advantages and disadvantages of these methods over the nonlinear method of chi(sup 2) minimization employed by the National Lightning Detection Network (NLDN) and discussed in Cummins et al.(1993, 1995, 1998).

  18. The lightning heart: a case report and brief review of the cardiovascular complications of lightning injury.

    Science.gov (United States)

    McIntyre, William F; Simpson, Christopher S; Redfearn, Damian P; Abdollah, Hoshiar; Baranchuk, Adrian

    2010-09-05

    Lightning strike is a rare natural phenomenon, which carries a risk of dramatic medical complications to multiple organ systems and a high risk of fatality. The known complications include but are not limited to: myocardial infarction, arrhythmia, cardiac contusion, stroke, cutaneous burns, respiratory disorders, neurological disorders, acute kidney injury and death. We report a case of a healthy young man who suffered a lightning injury and discuss the cardiovascular complications of lightning injury, ranging from ECG changes to death. The patient in our case, a 27-year old previously healthy male, developed a syndrome of rhabdomyolysis and symptomatic cardiogenic pulmonary edema. Electrocardiographic findings included transient T-wave inversions, late transition shift and long QT. His clinical condition improved with supportive measures.Early recognition of lightning injury syndromes and anticipation of complications may help us improve outcomes for these patients. Evaluation of patients having experienced a lightning injury should include a minimum of a detailed history and physical examination, 12-lead ECG and drawing of baseline troponins. Prolonged electrocardiographical monitoring (for monitoring of ventricular arrhythmias) and assessment for signs and symptoms of hemodynamic compromise may be warranted.

  19. Protective

    Directory of Open Access Journals (Sweden)

    Wessam M. Abdel-Wahab

    2013-10-01

    Full Text Available Many active ingredients extracted from herbal and medicinal plants are extensively studied for their beneficial effects. Antioxidant activity and free radical scavenging properties of thymoquinone (TQ have been reported. The present study evaluated the possible protective effects of TQ against the toxicity and oxidative stress of sodium fluoride (NaF in the liver of rats. Rats were divided into four groups, the first group served as the control group and was administered distilled water whereas the NaF group received NaF orally at a dose of 10 mg/kg for 4 weeks, TQ group was administered TQ orally at a dose of 10 mg/kg for 5 weeks, and the NaF-TQ group was first given TQ for 1 week and was secondly administered 10 mg/kg/day NaF in association with 10 mg/kg TQ for 4 weeks. Rats intoxicated with NaF showed a significant increase in lipid peroxidation whereas the level of reduced glutathione (GSH and the activity of superoxide dismutase (SOD, catalase (CAT, glutathione S-transferase (GST and glutathione peroxidase (GPx were reduced in hepatic tissues. The proper functioning of the liver was also disrupted as indicated by alterations in the measured liver function indices and biochemical parameters. TQ supplementation counteracted the NaF-induced hepatotoxicity probably due to its strong antioxidant activity. In conclusion, the results obtained clearly indicated the role of oxidative stress in the induction of NaF toxicity and suggested hepatoprotective effects of TQ against the toxicity of fluoride compounds.

  20. High lightning activity in maritime clouds near Mexico

    Directory of Open Access Journals (Sweden)

    B. Kucienska

    2012-01-01

    Full Text Available Lightning activity detected by the World Wide Lightning Location Network (WWLLN over oceanic regions adjacent to Mexico is often as high as that observed over the continent. In order to explore the possible cause of the observed high flash density over those regions, the relationships between lightning, rainfall, vertical hydrometeor profiles, latent heating, wind variability and aerosol optical thickness are analyzed. The characteristics of lightning and precipitation over four oceanic zones adjacent to Mexican coastlines are contrasted against those over the continent. In addition, we compare two smaller regions over the Tropical Pacific Ocean: one located within the Inter-Tropical Converge Zone and characterized by high rainfall and weak lightning activity and the other influenced by a continental jet and presenting high rainfall and strong lightning activity over the Gulf of Tehuantepec. Maritime precipitating clouds that develop within the region influenced by offshore winds exhibit similar properties to continental clouds: large content of precipitation ice and an increased height range of coexistence of precipitation ice and cloud water. During the rainy season, monthly distribution of lightning within the region influenced by the continental jet is contrary to that of rainfall. Moreover, the monthly variability of lightning is very similar to the variability of the meridional wind component and it is also related to the variability of aerosol optical depth. The analysis strongly suggests that the high lightning activity observed over the Gulf of Tehuantepec is caused by continental cloud condensation nuclei advected over the ocean.

  1. Predicting the Probability of Lightning Occurrence with Generalized Additive Models

    Science.gov (United States)

    Fabsic, Peter; Mayr, Georg; Simon, Thorsten; Zeileis, Achim

    2017-04-01

    This study investigates the predictability of lightning in complex terrain. The main objective is to estimate the probability of lightning occurrence in the Alpine region during summertime afternoons (12-18 UTC) at a spatial resolution of 64 × 64 km2. Lightning observations are obtained from the ALDIS lightning detection network. The probability of lightning occurrence is estimated using generalized additive models (GAM). GAMs provide a flexible modelling framework to estimate the relationship between covariates and the observations. The covariates, besides spatial and temporal effects, include numerous meteorological fields from the ECMWF ensemble system. The optimal model is chosen based on a forward selection procedure with out-of-sample mean squared error as a performance criterion. Our investigation shows that convective precipitation and mid-layer stability are the most influential meteorological predictors. Both exhibit intuitive, non-linear trends: higher values of convective precipitation indicate higher probability of lightning, and large values of the mid-layer stability measure imply low lightning potential. The performance of the model was evaluated against a climatology model containing both spatial and temporal effects. Taking the climatology model as a reference forecast, our model attains a Brier Skill Score of approximately 46%. The model's performance can be further enhanced by incorporating the information about lightning activity from the previous time step, which yields a Brier Skill Score of 48%. These scores show that the method is able to extract valuable information from the ensemble to produce reliable spatial forecasts of the lightning potential in the Alps.

  2. Analysis of Conditions favorable for Ball Lightning Creation

    CERN Document Server

    Boerner, H

    2016-01-01

    This report uses a few well documented cases of Ball Lightning (or BL for short) observations to demonstrate a correlation between BL and positive lightning, especially strong positive lightning. This allows to draw conclusions and predictions about future BL observations and the pro- duction of these objects in the laboratory. Contrary to many current BL theories, these objects can be created without direct contact to a lightning channel. Very high electric fields appear to be essential for the creation, together with the proper temporal structure of the field. So far no experiments have been performed along the ideas presented in this report.

  3. Cochlear implantation for severe sensorineural hearing loss caused by lightning.

    Science.gov (United States)

    Myung, Nam-Suk; Lee, Il-Woo; Goh, Eui-Kyung; Kong, Soo-Keun

    2012-01-01

    Lightning strike can produce an array of clinical symptoms and injuries. It may damage multiple organs and cause auditory injuries ranging from transient hearing loss and vertigo to complete disruption of the auditory system. Tympanic-membrane rupture is relatively common in patients with lightning injury. The exact pathogenetic mechanisms of auditory lesions in lightning survivors have not been fully elucidated. We report the case of a 45-year-old woman with bilateral profound sensorineural hearing loss caused by a lightning strike, who was successfully rehabilitated after a cochlear implantation. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. New method for lightning location using optical ground wire

    Science.gov (United States)

    Qin, Zhaoyu; Cheng, Zhaogu; Zhang, Zhiping; Zhu, Jianqiang; Li, Feng

    2006-12-01

    A new technology of lightning location is described, which is based on detecting the state of polarization (SOP) fluctuation of the laser light in the optic ground wire (OPGW). Compared with the conventional lightning location method, the new method is more accurate, more stable, and cheaper. Theories of Stokes parameters and Poincare sphere are introduced to analyze the SOP at the lightning strike point. It can be concluded that although the initial points of SOP on the Poincare sphere are random, the SOP fluctuation generated by lightning strike can still be accurately identified by detecting the velocity of polarization motion. A new algorithm to quantify the velocity is also introduced.

  5. Numerical Simulation of the Lightning Return Stroke.

    Science.gov (United States)

    da Frota Mattos, Marcos Andre

    Available from UMI in association with The British Library. Requires signed TDF. Several lightning return stroke models were developed in this work. Initially very simple models were developed, and subsequently many of the main features of the channel were added. The corona effect, the geometrical parameters, non-linear losses and the cloud losses are these features. To solve the RLC network model of the channel the numerical technique known as TLM was used. A numerical sensitivity study was made to analyse the influence of the filtering and the Gibbs effects on the results. A sensitivity study of the channel's parameters was also made. For the first time three of the main measured lightning channel quantities were calculated showing good agreement with observations. These quantities are the electromagnetic field, current waveshape at ground and the velocity of propagation. The surge impedence and the current rise-time were also calculated at all heights.

  6. Dust cloud lightning in extraterrestrial atmospheres

    CERN Document Server

    Helling, Christiane; Diver, Declan; Witte, Soeren

    2012-01-01

    Lightning is present in all solar system planets which form clouds in their atmospheres. Cloud formation outside our solar system is possible in objects with much higher temperatures than on Earth or on Jupiter: Brown dwarfs and giant extrasolar gas planets form clouds made of mixed materials and a large spectrum of grain sizes. These clouds are globally neutral obeying dust-gas charge equilibrium which is, on short timescales, inconsistent with the observation of stochastic ionization events of the solar system planets. We argue that a significant volume of the clouds in brown dwarfs and extrasolar planets is susceptible to local discharge events and that the upper cloud layers are most suitable for powerful lightning-like discharge events. We discuss various sources of atmospheric ionisation, including thermal ionisation and a first estimate of ionisation by cosmic rays, and argue that we should expect thunderstorms also in the atmospheres of brown dwarfs and giant gas planets which contain mineral clouds.

  7. Lightning Strikes and Attribution of Climatic Change

    CERN Document Server

    Webster, Anthony J

    2015-01-01

    Using lightning strikes as an example, two possible schemes are discussed for the attribution of changes in event frequency to climate change, and estimating the cost associated with them. The schemes determine the fraction of events that should be attributed to climatic change, and the fraction that should be attributed to natural chance. They both allow for the expected increase in claims and the fluctuations about this expected value. Importantly, the attribution fraction proposed in the second of these schemes is necessarily different to that found in epidemiological studies. This ensures that the statistically expected fraction of attributed claims is correctly equal to the expected increase in claims. The analysis of lightning data highlights two particular difficulties with data-driven, as opposed to modeled, attribution studies. The first is the possibility of unknown "confounding" variables that can influence the strike frequency. This is partly accounted for here by considering the influence of temp...

  8. Ionospheric effects of thunderstorms and lightning

    Energy Technology Data Exchange (ETDEWEB)

    Lay, Erin H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-02-03

    Tropospheric thunderstorms have been reported to disturb the lower ionosphere (~65-90 km) by convective atmospheric gravity waves and by electromagnetic field changes produced by lightning discharges. However, due to the low electron density in the lower ionosphere, active probing of its electron distribution is difficult, and the various perturbative effects are poorly understood. Recently, we have demonstrated that by using remotely-detected ?me waveforms of lightning radio signals it is possible to probe the lower ionosphere and its fluctuations in a spatially and temporally-resolved manner. Here we report evidence of gravity wave effects on the lower ionosphere originating from the thunderstorm. We also report variations in the nighttime ionosphere atop a small thunderstorm and associate the variations with the storm’s electrical activity. Finally, we present a data analysis technique to map ionospheric acoustic waves near thunderstorms.

  9. Runaway breakdown and hydrometeors in lightning initiation.

    Science.gov (United States)

    Gurevich, A V; Karashtin, A N

    2013-05-03

    The particular electric pulse discharges are observed in thunderclouds during the initiation stage of negative cloud-to-ground lightning. The discharges are quite different from conventional streamers or leaders. A detailed analysis reveals that the shape of the pulses is determined by the runaway breakdown of air in the thundercloud electric field initiated by extensive atmospheric showers (RB-EAS). The high amplitude of the pulse electric current is due to the multiple microdischarges at hydrometeors stimulated and synchronized by the low-energy electrons generated in the RB-EAS process. The series of specific pulse discharges leads to charge reset from hydrometeors to the free ions and creates numerous stretched ion clusters, both positive and negative. As a result, a wide region in the thundercloud with a sufficiently high fractal ion conductivity is formed. The charge transport by ions plays a decisive role in the lightning leader preconditioning.

  10. Enhanced FAA-hybrid III numerical dummy model in Madymo for aircraft occupant safety assessment

    NARCIS (Netherlands)

    Boucher, H.; Waagmeester, C.D.

    2003-01-01

    To improve survivability and to minimize the risk of injury to occupants in helicopter crash events, a complete Cabin Safety System concept including safety features and an enhanced FAA-Hybrid III dummy were developed within the HeliSafe project. A numerical tool was also created and validated to al

  11. 47 CFR 17.7 - Antenna structures requiring notification to the FAA.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Antenna structures requiring notification to..., MARKING, AND LIGHTING OF ANTENNA STRUCTURES Federal Aviation Administration Notification Criteria § 17.7 Antenna structures requiring notification to the FAA. A notification to the Federal...

  12. Investigation of the radiation risk due to environmental contamination by 241Am from lightning rods disposed at uncontrolled garbage dumps.

    Science.gov (United States)

    Marumo, Júlio T; Isiki, Vera L K; Miyamoto, Hissae; Ferreira, Rafael V P; Bellini, Maria H; de Lima, Luis F C P

    2008-02-01

    Radioactive lightning rods were manufactured in Brazil until 1989, when the licenses for using radioactive sources in these products were lifted by the national nuclear authority. Since then, these rods have been replaced by the Franklin type and collected as radioactive waste. However, only 20% of the estimated total number of installed rods has been delivered to the Brazilian Nuclear Commission. This situation causes concern, since there is the possibility of the rods to be disposed as domestic waste. In Brazil, 64% of the municipal solid waste is disposed at garbage dumps without sufficient control. In addition, (241)Am, the radionuclide most commonly employed, is classified as a high-toxicity element, when incorporated. In the present study, (241)Am migration experiments were performed by means of a lysimeter system, in order to evaluate the risk of contamination caused by radioactive lightning rods disposed as common solid waste. (241)Am sources removed from lightning rods were placed inside lysimeters filled with organic waste that was collected at the restaurant of the Instituto de Pesquisas Energéticas e Nucleares. The generated leachate was periodically analyzed, and characteristics such as pH, redox potential, solid content and the concentration of the radioactive material were determined. The equivalent dose for members of the public was calculated considering ingestion of contaminated drinking water as the major path of exposure. Estimated doses were about 20-times below the effective dose limit of 1 mSv year(-1) for members of the public as recommended by the International Commission on Radiological Protection. This suggests the radiation risk caused by lightning rods disposed at uncontrolled garbage dumps to be low. It should be noted, however, that the number of investigated lightning rods was quite small. The results of this study might therefore not be entirely representative and should be interpreted with care. They provide, however, a very first

  13. Lightning Risk Evaluation on Thermal Power Plant%热电厂雷电灾害风险评估

    Institute of Scientific and Technical Information of China (English)

    金雯晴; 王涪德; 陈晓东

    2012-01-01

    雷电灾害风险评估是防雷设计之前最重要的环节。从风险理论入手,简单介绍了风险、风险评估、自然灾害风险评估等概念,建立了一个较清晰的风险评估框架体系。针对热电厂的特殊结构,简化风险评估模型,用IEC 62305-2雷电灾害风险评估的评估方法对其进行雷击风险评估。结果显示,雷击风险主要是来自雷击建筑物及其相连线路造成的物理损害所引起的,需要在入户的架空电缆等设施上安装浪涌保护器,使热电厂达到高效防雷的目的。%The risk evaluation work of lightning is the most important procedure of the lightning prevention work. Starting from the risk theory, the concept of risk, risk evaluation and risk evaluation for natural disasters were introduced. A specific framework for risk evaluation was established. Then aiming at the special structure of thermal power plant, the evaluation model was simplified and the evaluation work using the method in IEC 62305-2 risk evaluation for lightning disaster were done. The results showed that the lightning risk is mainly attributed to the physical damage in the main building and the circuit caused by lightning. Thus we should install surge protection device on aerial cable connecting to indoor space, to achieve the purpose of efficient lightning prevention work for thermal power plant.

  14. An Assessment of Land Surface and Lightning Characteristics Associated with Lightning-Initiated Wildfires

    Science.gov (United States)

    Coy, James; Schultz, Christopher J.; Case, Jonathan L.

    2017-01-01

    Can we use modeled information of the land surface and characteristics of lightning beyond flash occurrence to increase the identification and prediction of wildfires? Combine observed cloud-to-ground (CG) flashes with real-time land surface model output, and Compare data with areas where lightning did not start a wildfire to determine what land surface conditions and lightning characteristics were responsible for causing wildfires. Statistical differences between suspected fire-starters and non-fire-starters were peak-current dependent 0-10 cm Volumetric and Relative Soil Moisture comparisons were statistically dependent to at least the p = 0.05 independence level for both polarity flash types Suspected fire-starters typically occurred in areas of lower soil moisture than non-fire-starters. GVF value comparisons were only found to be statistically dependent for -CG flashes. However, random sampling of the -CG non-fire starter dataset revealed that this relationship may not always hold.

  15. Joint voltages resulting from lightning currents.

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, William Arthur; Warne, Larry Kevin; Merewether, Kimball O.; Chen, Kenneth C.

    2007-03-01

    Simple formulas are given for the interior voltages appearing across bolted joints from exterior lightning currents. External slot and bolt inductances as well as internal slot and bolt diffusion effects are included. Both linear and ferromagnetic wall materials are considered. A useful simplification of the slot current distribution into linear stripline and cylindrical parts (near the bolts) allows the nonlinear voltages to be estimated in closed form.

  16. Simulation of Meteosat Third Generation-Lightning Imager through tropical rainfall measuring mission: Lightning Imaging Sensor data

    Science.gov (United States)

    Biron, Daniele; De Leonibus, Luigi; Laquale, Paolo; Labate, Demetrio; Zauli, Francesco; Melfi, Davide

    2008-08-01

    The Centro Nazionale di Meteorologia e Climatologia Aeronautica recently hosted a fellowship sponsored by Galileo Avionica, with the intent to study and perform a simulation of Meteosat Third Generation - Lightning Imager (MTG-LI) sensor behavior through Tropical Rainfall Measuring Mission - Lightning Imaging Sensor data (TRMM-LIS). For the next generation of earth observation geostationary satellite, major operating agencies are planning to insert an optical imaging mission, that continuously observes lightning pulses in the atmosphere; EUMETSAT has decided in recent years that one of the three candidate mission to be flown on MTG is LI, a Lightning Imager. MTG-LI mission has no Meteosat Second Generation heritage, but users need to evaluate the possible real time data output of the instrument to agree in inserting it on MTG payload. Authors took the expected LI design from MTG Mission Requirement Document, and reprocess real lightning dataset, acquired from space by TRMM-LIS instrument, to produce a simulated MTG-LI lightning dataset. The simulation is performed in several run, varying Minimum Detectable Energy, taking into account processing steps from event detection to final lightning information. A definition of the specific meteorological requirements is given from the potential use in meteorology of lightning final information for convection estimation and numerical cloud modeling. Study results show the range of instrument requirements relaxation which lead to minimal reduction in the final lightning information.

  17. An Optical Lightning Simulator in an Electrified Cloud-Resolving Model to Prepare the Future Space Lightning Missions

    Science.gov (United States)

    Bovalo, Christophe; Defer, Eric; Pinty, Jean-Pierre

    2016-04-01

    The future decade will see the launch of several space missions designed to monitor the total lightning activity. Among these missions, the American (Geostationary Lightning Mapper - GLM) and European (Lightning Imager - LI) optical detectors will be onboard geostationary satellites (GOES-R and MTG, respectively). For the first time, the total lightning activity will be monitored over the full Earth disk and at a very high temporal resolution (2 and 1 ms, respectively). Missions like the French Tool for the Analysis of Radiation from lightNIng and Sprites (TARANIS) and ISS-LIS will bring complementary information in order to better understand the lightning physics and to improve the weather prediction (nowcasting and forecasting). Such missions will generate a huge volume of new and original observations for the scientific community and weather prediction centers that have to be prepared. Moreover, before the launch of these missions, fundamental questions regarding the interpretation of the optical signal property and its relation to cloud optical thickness and lightning discharge processes need to be further investigated. An innovative approach proposed here is to use the synergy existing in the French MesoNH Cloud-Resolving Model (CRM). Indeed, MesoNH is one of the only CRM able to simulate the lifecycle of electrical charges generated within clouds through non-inductive charging process (dependent of the 1-moment microphysical scheme). The lightning flash geometry is based on a fractal law while the electrical field is diagnosed thanks to the Gauss' law. The lightning optical simulator is linked to the electrical scheme as the lightning radiance at 777.4 nm is a function of the lightning current, approximated by the charges neutralized along the lightning path. Another important part is the scattering of this signal by the hydrometeors (mainly ice particles) that is taken into account. Simulations at 1-km resolution are done over the Langmuir Laboratory (New

  18. Acoustic vs Interferometric Measurements of Lightning

    Science.gov (United States)

    Arechiga, R. O.; Erives, H.; Sonnenfeld, R. G.; Stanley, M. A.; Rison, W.; Thomas, R. J.; Edens, H. E.; Lapierre, J. L.; Stock, M.; Jensen, D.; Morris, K.

    2015-12-01

    During the summer of 2015 we acquired acoustic and RF data on severalflashes from thunderstorms over Fort Morgan CO. and Langmuir Laboratoryin the Magdalena mountains of central New Mexico. The acoustic arrayswere located at a distance of roughly 150 m from the interferometers.Lightning mapping array and slow antenna data were also obtained. Theacoustic arrays consist of arrays of five audio-range and six infrasoundmicrophones operating at 50 KHz and 1 KHz respectively. The lightninginterferometer at Fort Morgan CO. consists of three flat-plate, 13" diameterantennas at the vertices of an equilateral 50 m per side triangle. Theinterferometer at Langmuir Laboratory consists of three 13" dishes separatedby about 15 m. Both interferometers, operating at 180 Megasamples persecond, use the analysis software and digitizer hardware pioneered byStanley, Stock et al. The high data rate allows for excellent spatialresolution of high speed (and typically high current) processes such asK-changes, return strokes and dart-leaders. In previous studies, we haveshown the usefulness of acoustic recordings to locate thunder sources aswell as infrasound pulses from lightning. This work will present acomparison of Acoustic and Interferometric measurements from lightning,using some interesting flashes, including a positive cloud to ground,that occurred in these campaigns.

  19. Aerodynamically generated noise by lightning arrester

    Directory of Open Access Journals (Sweden)

    Váchová J.

    2007-10-01

    Full Text Available This paper presents the general solution of aerodynamically generated noise by lightning arrester. Governing equations are presented in form of Lighthill acoustic analogy, as embodied in the Ffowcs Williams-Hawkings (FW-H equation. This equation is based on conservation laws of fluid mechanics rather than on the wave equation. Thus, the FW-H equation is valid even if the integration surface is in nonlinear region. That’s why the FWH method is superior in aeroacoustics. The FW-H method is implemented in program Fluent and the numerical solution is acquired by Fluent code.The general solution of acoustic signal generated by lightning arrester is shown and the results in form of acoustic pressure and frequency spectrum are presented. The verification of accuracy was made by evaluation of Strouhal number. A comparison of Strouhal number for circumfluence of a cylinder and the lightning arrester was done, because the experimental data for cylinder case are known and these solids are supposed to be respectively in shape relation.

  20. Impact of lightning strikes on hospital functions.

    Science.gov (United States)

    Mortelmans, Luc J M; Van Springel, Gert L J; Van Boxstael, Sam; Herrijgers, Jan; Hoflacks, Stefaan

    2009-01-01

    Two regional hospitals were struck by lightning during a one-month period. The first hospital, which had 236 beds, suffered a direct strike to the building. This resulted in a direct spread of the power peak and temporary failure of the standard power supply. The principle problems, after restoring standard power supply, were with the fire alarm system and peripheral network connections in the digital radiology systems. No direct impact on the hardware could be found. Restarting the servers resolved all problems. The second hospital, which had 436 beds, had a lightning strike on the premises and mainly experienced problems due to induction. All affected installations had a cable connection from outside in one way or another. The power supplies never were endangered. The main problem was the failure of different communication systems (telephone, radio, intercom, fire alarm system). Also, the electronic entrance control went out. During the days after the lightening strike, multiple software problems became apparent, as well as failures of the network connections controlling the technical support systems. There are very few ways to prepare for induction problems. The use of fiber-optic networks can limit damage. To the knowledge of the authors, these are the first cases of lightning striking hospitals in medical literature.

  1. Lightning flash multiplicity in eastern Mediterranean thunderstorms

    Science.gov (United States)

    Yair, Y.; Shalev, S.; Erlich, Z.; Agrachov, A.; Katz, E.; Saaroni, H.; Price, C.; Ziv, B.

    2014-02-01

    Cloud-to-ground lightning flashes usually consist of one or several strokes coming in very short temporal succession and close spatial proximity. A commonly used method for converting stroke data into flashes is using the National Lightning Detection Network (NLDN) thresholds of maximum temporal separation of 0.5 s and maximum lateral distance of 10 km radius between successive strokes. In the present study, we tested a location-based algorithm with several spatial and temporal ranges, and analyzed stroke data obtained by the Israel Lightning Location System (ILLS) during one year (1.8.2009-31.7.2010). We computed the multiplicity, the percentage of single stroke flashes and the geographical distribution of average multiplicity values for thunderstorms in the Eastern Mediterranean region. Results show that for the NLDN thresholds, the percentage of single stroke flashes in Israel was 37% and the average multiplicity was 1.7. We reanalyzed the data with a spatial range that equals twice the ILLS location error and shorter times. For the new thresholds of maximum distance of 2.5 km and maximum allowed temporal separation of 0.2 s we find that the mean multiplicity of negative CGs is lowered to 1.4 and find a percentage of 58% of single stroke flashes. A unique severe storm from 30 October 2009 is analyzed and compared with the annual average of 2009/2010, showing that large deviations from the mean values can occur in specific events.

  2. Comparison between EDXRF and FAAS for Zn determination in terrestrial molluscs

    Energy Technology Data Exchange (ETDEWEB)

    Melo, Julyanne T.B.; Cantinha, Rebeca S.; Santos, Mariana L.O.; Santos, Katarine M.B.; Franca, Elvis J., E-mail: julyanne.melo@ufpe.br, E-mail: rebecanuclear@gmail.com, E-mail: marianasantos_ufpe@hotmail.com, E-mail: katarine.mizan@gmail.com, E-mail: ejfranca@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Melo, Ana M.M.A., E-mail: amdemelo@hotmail.com [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Biofisica e Radiobiologia

    2015-07-01

    Even with the most advanced analytical techniques, achieving the true values of a given analyte in a sample cannot be an easy task. Energy Dispersive X-Ray Fluorescence (EDXRF) and Flame Atomic Absorption Spectrometry (FAAS) have been widely used for analysis of the chemical composition of biological matrices in environmental studies. However, depending on the sample matrix, a combination of techniques could be needed for the correct determination of the analyte. Zinc distribution in Littoraria angulifera and Melampus coffea is quite dependent on the environment, so that, diverse methods could be necessary to evaluate the chemical composition of these mollusks. This study aimed at the comparison between EDXRF and FAAS techniques for determining Zn in the soft tissues of terrestrial mollusks. The animals were collected in three mangroves in the State of Pernambuco, Brazil. After shell removal, tissues were lyophilized and milled in a mortar. Test portions of 500 mg were analyzed by EDXRF, followed by chemical treatment for FAAS analysis. For the quality of the analytical procedure, the standard reference material SRM 2976 Mussel Tissue was analyzed together with the samples. The results for the analysis of the certified reference material SRM 2976 indicated the quality of the analytical procedure for both techniques. Adjusted-R{sup 2} between EDXRF and FAAS results was 0.95, indicating a good equivalence of Zn determination by both techniques. However, some improvement of EDXRF determination could be necessary because of the tendency of lower results compared to FAAS, probably related to spectral interferences during the analysis. (author)

  3. Review of the Lightning Shielding Against Direct Lightning Strokes Based on Laboratory Long Air Gap Discharges

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    It is one of the most effective ways to use laboratory long air gap discharges tbr investigating the fundamental process involved in the lightning strike. During the 1960s and the 1970s, the electro-geometrical method (EGM) and the rolling sphere method were developed base on the breakdown characteristics of negative long spark discharges, which have been widely used to design the lightning shielding system of transmission lines and structures. In recent years, the scale of the power facilities is increased dramatically with the rising of power grid's voltage level.

  4. Estimates of lightning NOx production from GOME satellite observations

    Directory of Open Access Journals (Sweden)

    K. F. Boersma

    2005-01-01

    Full Text Available Tropospheric NO2 column retrievals from the Global Ozone Monitoring Experiment (GOME satellite spectrometer are used to quantify the source strength and 3-D distribution of lightning produced nitrogen oxides (NOx=NO+NO2. A sharp increase of NO2 is observed at convective cloud tops with increasing cloud top height, consistent with a power-law behaviour with power 5±2. Convective production of clouds with the same cloud height are found to produce NO2 with a ratio 1.6/1 for continents compared to oceans. This relation between cloud properties and NO2 is used to construct a 10:30 local time global lightning NO2 production map for 1997. An extensive statistical comparison is conducted to investigate the capability of the TM3 chemistry transport model to reproduce observed patterns of lightning NO2 in time and space. This comparison uses the averaging kernel to relate modelled profiles of NO2 to observed NO2 columns. It exploits a masking scheme to minimise the interference of other NOx sources on the observed total columns. Simulations are performed with two lightning parameterizations, one relating convective preciptation (CP scheme to lightning flash distributions, and the other relating the fifth power of the cloud top height (H5 scheme to lightning distributions. The satellite-retrieved NO2 fields show significant correlations with the simulated lightning contribution to the NO2 concentrations for both parameterizations. Over tropical continents modelled lightning NO2 shows remarkable quantitative agreement with observations. Over the oceans however, the two model lightning parameterizations overestimate the retrieved NO2 attributed to lightning. Possible explanations for these overestimations are discussed. The ratio between satellite-retrieved NO2 and modelled lightning NO2 is used to rescale the original modelled lightning NOx production. Eight estimates of the lightning NOx production in 1997 are obtained from spatial and temporal

  5. Estimates of lightning NOx production from GOME satellite observations

    Directory of Open Access Journals (Sweden)

    H. M. Kelder

    2005-05-01

    Full Text Available Tropospheric NO2 column retrievals from the Global Ozone Monitoring Experiment (GOME satellite spectrometer are used to quantify the source strength and 3D distribution of lightning produced nitrogen oxides (NOx=NO2+NO2. A sharp increase of NO2 is observed at convective cloud tops with increasing cloud top height, consistent with a power-law behaviour with power 5±2. Convective production of clouds with the same cloud height are found to produce NO2 with a ratio 1.6/1 for continents compared to oceans. This relation between cloud properties and NO2 is used to construct a 10:30 local time global lightning NO2 production map for 1997. An extensive statistical comparison is conducted to investigate the capability of the TM3 chemistry transport model to reproduce observed patterns of lightning NO2 in time and space. This comparison uses the averaging kernel to relate modelled profiles of NO2 to observed NO2 columns. It exploits a masking scheme to minimise the interference of other NOx sources on the observed total columns. Simulations are performed with two lightning parametrisations, one relating convective preciptation (CP scheme to lightning flash distributions, and the other relating the fifth power of the cloud top height (H5 scheme to lightning distributions. The satellite-retrieved NO2 fields show significant correlations with the simulated lightning contribution to the NO2 concentrations for both parametrisations. Over tropical continents modelled lightning NO2 shows remarkable quantitative agreement with observations. Over the oceans however, the two model lightning parametrisations overestimate the retrieved NO2 attributed to lightning. Possible explanations for these overestimations are discussed. The ratio between satellite-retrieved NO2 and modelled lightning NO2 is used to rescale the original modelled lightning NOx production. Eight estimates of the lightning NOx production in 1997 are obtained from spatial and temporal correlation

  6. Quantification and identification of lightning damage in tropical forests.

    Science.gov (United States)

    Yanoviak, Stephen P; Gora, Evan M; Burchfield, Jeffrey M; Bitzer, Phillip M; Detto, Matteo

    2017-07-01

    Accurate estimates of tree mortality are essential for the development of mechanistic forest dynamics models, and for estimating carbon storage and cycling. However, identifying agents of tree mortality is difficult and imprecise. Although lightning kills thousands of trees each year and is an important agent of mortality in some forests, the frequency and distribution of lightning-caused tree death remain unknown for most forests. Moreover, because all evidence regarding the effects of lightning on trees is necessarily anecdotal and post hoc, rigorous tests of hypotheses regarding the ecological effects of lightning are impossible. We developed a combined electronic sensor/camera-based system for the location and characterization of lightning strikes to the forest canopy in near real time and tested the system in the forest of Barro Colorado Island, Panama. Cameras mounted on towers provided continuous video recordings of the forest canopy that were analyzed to determine the locations of lightning strikes. We used a preliminary version of this system to record and locate 18 lightning strikes to the forest over a 3-year period. Data from field surveys of known lightning strike locations (obtained from the camera system) enabled us to develop a protocol for reliable, ground-based identification of suspected lightning damage to tropical trees. In all cases, lightning damage was relatively inconspicuous; it would have been overlooked by ground-based observers having no knowledge of the event. We identified three types of evidence that can be used to consistently identify lightning strike damage in tropical forests: (1) localized and directionally biased branch mortality associated with flashover among tree and sapling crowns, (2) mortality of lianas or saplings near lianas, and (3) scorched or wilting epiphytic and hemiepiphytic plants. The longitudinal trunk scars that are typical of lightning-damaged temperate trees were never observed in this study. Given the

  7. 电视转播台雷电防范及措施%Prevention and Measures for Alpine TV Station Lightning

    Institute of Scientific and Technical Information of China (English)

    吴少芳

    2016-01-01

    Based on the fact that the mountain stations vulnerable to lightning,this paper demonstrates light-ning protection measures from the perspective of ground grid,equipotential connection and multilevel lightning protection respectively.After modification,the probability of accidents caused by lighting are greatly reduced, and has attained remarkable results.%针对高山台站易受雷击破坏的特点,分别从接地网、等电位连接和多级浪涌避雷防护等方面叙述了雷击的防范措施,通过防雷技术改造后,雷击造成设备事故的概率大大减少,取得了明显的成效。

  8. Lightning climatology in the Congo Basin

    Science.gov (United States)

    Soula, S.; Kasereka, J. Kigotsi; Georgis, J. F.; Barthe, C.

    2016-09-01

    The lightning climatology of the Congo Basin including several countries of Central Africa is analysed in detail for the first time. It is based on data from the World Wide Lightning Location Network (WWLLN), for the period from 2005 to 2013. A comparison of these data with Lightning Imaging Sensor (LIS) data for the same period shows the relative detection efficiency of the WWLLN (DE) in the 2500 km × 2500 km region increases from about 1.70% in the beginning of the period to 5.90% in 2013, and it is in agreement with previous results for other regions of the world. However, the increase of DE is not uniform over the whole region. The average monthly flash rate describes an annual cycle with a strong activity from October to March and a low one from June to August, associated with the ITCZ migration but not exactly symmetrical on both sides of the equator. The zonal distribution of the lightning flashes exhibits a maximum between 1°S and 2°S and about 56% of the flashes are located south of the equator in the 10°S-10°N interval. The diurnal evolution of the flash rate has a maximum between 1400 and 1700 UTC, according to the reference year. The annual flash density and number of stormy days show a sharp maximum localized in the eastern part of Democratic Republic of Congo (DRC) regardless of the reference year and the period of the year. These maxima reach 12.86 fl km- 2 and 189 days, respectively, in 2013, and correspond to a very active region located at the rear of the Virunga mountain range at altitudes that exceed 3000 m. The presence of these mountains plays a role in the thunderstorm development along the year. The estimation of this local maximum of the lightning density by taking into account the DE, leads to a value consistent with that of the global climatology by Christian et al. (2003).

  9. METHODS OF MEASURING THE EFFECTS OF LIGHTNING BY SIMULATING ITS STRIKES WITH THE INTERVAL ASSESSMENT OF THE RESULTS OF MEASUREMENTS

    Directory of Open Access Journals (Sweden)

    P. V. Kriksin

    2017-01-01

    Full Text Available The article presents the results of the development of new methods aimed at more accurate interval estimate of the experimental values of voltages on grounding devices of substations and circuits in the control cables, that occur when lightning strikes to lightning rods; the abovementioned estimate made it possible to increase the accuracy of the results of the study of lightning noise by 28 %. A more accurate value of interval estimation were achieved by developing a measurement model that takes into account, along with the measured values, different measurement errors and includes the special processing of the measurement results. As a result, the interval of finding the true value of the sought voltage is determined with an accuracy of 95 %. The methods can be applied to the IK-1 and IKP-1 measurement complexes, consisting in the aperiodic pulse generator, the generator of high-frequency pulses and selective voltmeters, respectively. To evaluate the effectiveness of the developed methods series of experimental voltage assessments of grounding devices of ten active high-voltage substation have been fulfilled in accordance with the developed methods and traditional techniques. The evaluation results confirmed the possibility of finding the true values of voltage over a wide range, that ought to be considered in the process of technical diagnostics of lightning protection of substations when the analysis of the measurement results and the development of measures to reduce the effects of lightning are being fulfilled. Also, a comparative analysis of the results of measurements made in accordance with the developed methods and traditional techniques has demonstrated that the true value of the sought voltage may exceed the measured value at an average of 28 %, that ought to be considered in the further analysis of the parameters of lightning protection at the facility and in the development of corrective actions. The developed methods have been

  10. 常州雷灾分布特征及风险区划%Characteristics of lightning disaster distribution and risk zoning of Changzhou

    Institute of Scientific and Technical Information of China (English)

    钟颖颖; 束建; 朱恺; 刘红银

    2014-01-01

    The correlation between thunderstorm and lightning disaster is analyzed,based on thunderstorm data in past 60 years,lightning data in recent 5 years and lightning disasters in past 10 years of Changzhou. Results show that the occurrence of lightning disaster can not be solely attributed to natural factors like thunderstorm,flash;an-thropogenic factors like economic development,population density,and lightning protection level may also influence the occurrence and level of lightning disaster.In the loss caused by lightning,failure of electrical and electronic sys-tem accounts for the largest proportion.And the local residents are the most vulnerable to lightning disasters in all industries,which is associated with people�s indifference to lightning protection and short of lightning protection de-vice for residential buildings.Combined with actual situation,7 indexes are put forward to evaluate the lightning dis-aster vulnerability of Changzhou, including thunderstorm days, lightning density, lightning disaster frequency, eco-nomic development, population density, vulnerability of economy and population. Based on data about the population,area and economy in all districts of Changzhou from the statistical yearbook of Jiangsu,lightning disaster vulnerability risk of each district is calculated by analytic hierarchy method,and the risk zoning is classified as high risk area(Wujin district),relatively high risk area(Tianning district and Jintan city),middle risk area(Zhonglou district,Qishuyan district and Liyang city) and low risk area( Xinbei district) .%根据常州近50 a的雷暴数据、近5 a的闪电数据和近10 a的雷灾资料,分析了雷暴和雷灾的相关性,结果表明:雷灾的发生不止与雷暴、闪电等自然因素有关,还可能与地区经济人口分布、区域雷电防护水平等人为因素有关;在雷击造成的损失中,电气和电子系统失效的损害占的比例最大,居民用户遭受雷灾的比重最大

  11. Unusual features caused by lightning impact in West Greenland

    DEFF Research Database (Denmark)

    Appel, P.; Abrahamsen, N.; Rasmussen, T.

    2006-01-01

    that a strong electric current indeed traversed the boulder. A few years later a second lightning impacted on a mountaintop close to the first impact. The second lightning left a trail on the rock surface covered by a thin layer of glass. The glass displays spectacular colours ranging from metallic blue, to red...

  12. Lightning location system supervising Swedish power transmission network

    Science.gov (United States)

    Melin, Stefan A.

    1991-01-01

    For electric utilities, the ability to prevent or minimize lightning damage on personnel and power systems is of great importance. Therefore, the Swedish State Power Board, has been using data since 1983 from a nationwide lightning location system (LLS) for accurately locating lightning ground strikes. Lightning data is distributed and presented on color graphic displays at regional power network control centers as well as at the national power system control center for optimal data use. The main objectives for use of LLS data are: supervising the power system for optimal and safe use of the transmission and generating capacity during periods of thunderstorms; warning service to maintenance and service crews at power line and substations to end operations hazardous when lightning; rapid positioning of emergency crews to locate network damage at areas of detected lightning; and post analysis of power outages and transmission faults in relation to lightning, using archived lightning data for determination of appropriate design and insulation levels of equipment. Staff have found LLS data useful and economically justified since the availability of power system has increased as well as level of personnel safety.

  13. Integration of Lightning- and Human-Caused Wildfire Occurrence Models

    DEFF Research Database (Denmark)

    Vilar, Lara; Nieto Solana, Hector; Martín, M. Pilar

    2010-01-01

    Fire risk indices are useful tools for fire prevention actions by fire managers. A fire ignition is either the result of lightning or human activities. In European Mediterranean countries most forest fires are due to human activities. However, lightning is still an important fire ignition source ...

  14. Lightning characteristics of derecho producing mesoscale convective systems

    Science.gov (United States)

    Bentley, Mace L.; Franks, John R.; Suranovic, Katelyn R.; Barbachem, Brent; Cannon, Declan; Cooper, Stonie R.

    2016-06-01

    Derechos, or widespread, convectively induced wind storms, are a common warm season phenomenon in the Central and Eastern United States. These damaging and severe weather events are known to sweep quickly across large spatial regions of more than 400 km and produce wind speeds exceeding 121 km h-1. Although extensive research concerning derechos and their parent mesoscale convective systems already exists, there have been few investigations of the spatial and temporal distribution of associated cloud-to-ground lightning with these events. This study analyzes twenty warm season (May through August) derecho events between 2003 and 2013 in an effort to discern their lightning characteristics. Data used in the study included cloud-to-ground flash data derived from the National Lightning Detection Network, WSR-88D imagery from the University Corporation for Atmospheric Research, and damaging wind report data obtained from the Storm Prediction Center. A spatial and temporal analysis was conducted by incorporating these data into a geographic information system to determine the distribution and lightning characteristics of the environments of derecho producing mesoscale convective systems. Primary foci of this research include: (1) finding the approximate size of the lightning activity region for individual and combined event(s); (2) determining the intensity of each event by examining the density and polarity of lightning flashes; (3) locating areas of highest lightning flash density; and (4) to provide a lightning spatial analysis that outlines the temporal and spatial distribution of flash activity for particularly strong derecho producing thunderstorm episodes.

  15. Lightning, IT Diffusion and Economic Growth across US States

    DEFF Research Database (Denmark)

    Andersen, Thomas Barnebeck; Bentzen, Jeanet; Dalgaard, Carl-Johan Lars;

    Empirically, a higher frequency of lightning strikes is associated with slower growth in labor productivity across the 48 contiguous US states after 1990; before 1990 there is no correlation between growth and lightning. Other climate variables (e.g., temperature, rainfall and tornadoes) do not c...

  16. Lightning Sensors for Observing, Tracking and Nowcasting Severe Weather.

    Science.gov (United States)

    Price, Colin

    2008-01-21

    Severe and extreme weather is a major natural hazard all over the world, oftenresulting in major natural disasters such as hail storms, tornados, wind storms, flash floods,forest fires and lightning damages. While precipitation, wind, hail, tornados, turbulence,etc. can only be observed at close distances, lightning activity in these damaging stormscan be monitored at all spatial scales, from local (using very high frequency [VHF]sensors), to regional (using very low frequency [VLF] sensors), and even global scales(using extremely low frequency [ELF] sensors). Using sensors that detect the radio wavesemitted by each lightning discharge, it is now possible to observe and track continuouslydistant thunderstorms using ground networks of sensors. In addition to the number oflightning discharges, these sensors can also provide information on lightningcharacteristics such as the ratio between intra-cloud and cloud-to-ground lightning, thepolarity of the lightning discharge, peak currents, charge removal, etc. It has been shownthat changes in some of these lightning characteristics during thunderstorms are oftenrelated to changes in the severity of the storms. In this paper different lightning observingsystems are described, and a few examples are provided showing how lightning may beused to monitor storm hazards around the globe, while also providing the possibility ofsupplying short term forecasts, called nowcasting.

  17. Lightning severity in Malaysia and some parameters of interest for engineering applications

    Directory of Open Access Journals (Sweden)

    Ab-Kadir Mohd Zainal Abidin

    2016-01-01

    Full Text Available To the electric utility engineer, the parameters of the flash that are of primary interest are the crest current for the first and subsequent strokes, the waveshape of these currents, correlation between the parameters, the number of strokes per flash and flash incidence rates where the ground flash density, denoted as flashes per square km-year and symbolized by Ng. The first three parameters, as we know them today, are to a very large extent based on the measurements of Berger. Berger's masts, 70 and 80 meters high, were mounted atop Mt. San Salvatore (Switzerland, which is 650 meters above Lake Lugano, where it can be readily noted that these 125 records represent one of the best and most extensive set of data available to the industry to date. This paper focuses on the lightning severity scenario in Malaysia, which could also applicable to other tropic countries, and some of the useful parameters for lightning protection system design and forensic study. Some specific engineering applications have also been summarised, taking into account various lightning parameters, available from past and current measurements available.

  18. A Lightning Detector Onboard Austrian Nanosatellite (LiNSAT)

    Science.gov (United States)

    Jaffer, G.; Koudelka, O.; Schwingenschuh, K.; Eichelberger, H.

    2010-12-01

    This paper presents architecture of a lightning detector onboard future Austrian Lightning Nanosatellite (LiNSAT) in low-earth-orbit (LEO) and results of two terrestrial measurement campaigns to geo-locate and discriminate lightning types in presence of noise sources. The LiNSAT is proposed to be launched with three satellites constellation for the purpose of Time-of-Arrival technique. Our main scientific objective is to investigate lightning events by the observation of VHF electromagnetic signals (Sferics) and to derive the signatures of lightning. One of the important parameters is lightning flash rate, which can be used as a proxy for locating severe weather activity. Another objective is to discriminate the discharges of lightning events evaluated by the inherent features and to differentiate cloud discharges (IC; intercloud and Intracloud) from ground discharges (CG; cloud-to-ground), return strokes, leaders and transionospheric pulse pairs. The discrimination is important because the ratio of the two (IC/CG) is a good indicator of convective storm development. We conducted two measurement campaigns; one for artificial lightning produced in high voltage chamber and second natural lightning recorded at urban environment. We focus mainly on envelopes of the received time series including noisy features and narrowband carriers to extract characteristic parameters. We determined the chamber inter-walls distance by considering reflections in the first measurements. Initially the algorithm for the instruments onboard electronics has been developed and verified in Matlab and will be transformed to machine language. Next consideration is to use existing lightning data from previous French mission “DEMETER” to validate the accomplished results. The lightning detector onboard has to perform tasks like determination of pulse-width, pulse-count, pulse rise/fall time etc; we get noise possibly from narrowband carriers and artifacts from satellite itself (EMC) in

  19. Bayesian techniques to analyze and merge lightning locating system data

    Science.gov (United States)

    Bitzer, Phillip M.; Burchfield, Jeffrey C.

    2016-12-01

    As more lightning locating systems (LLSs) become available, there is a growing need to assess how each LLS performs and how to best merge data from multiple LLSs. A Bayesian analysis is used to compare the worldwide data of LLSs from three providers for November 2014 to October 2015: Earth Networks Total Lightning Network (ENTLN, Earth Networks), the combined data from the Global Lightning Detection 360 and National Lightning Detection Network (Vaisala), and the World Wide Lightning Location Network (WWLLN, University of Washington). By using the union of the data sets we are able to determine an estimate for the upper limit of the absolute detection efficiency of each system. Globally, ENTLN detected 56.8% of the discharges, the combined Vaisala networks detected 59.8%, and WWLLN detected 7.9%. In addition, there were 2.842 × 109 unique discharges detected by these LLSs, an average of 90.1 strokes/s.

  20. Spatial Variation of the Correlated Color Temperature of Lightning Channel

    CERN Document Server

    Shimoji, Nobuaki; Sakihama, Singo

    2014-01-01

    In this paper, we studied the spatial variation of the correlated color temperature (CCT) of lightning channel. We also discussed the energy of lightning channels relating to the CCT . First we applied digital image processing techniques to lightning images. In order to reduce the chromatic aberration, we created the reduction technique algorithm of the chromatic aberration on digital still images. We applied the reduction technique of the chromatic aberration to digital still images, and then the obtained results was mapped to the xy-chromaticity diagram. The CCT of the lightning channel was decided on the xy-chromaticity diagram. From results, the spatial variation of the CCT of the lightning channel was confirmed. Then the energy associated with the the CCT was discussed.

  1. Integration of Lightning- and Human-Caused Wildfire Occurrence Models

    DEFF Research Database (Denmark)

    Vilar, Lara; Nieto Solana, Hector; Martín, M. Pilar

    2010-01-01

    Fire risk indices are useful tools for fire prevention actions by fire managers. A fire ignition is either the result of lightning or human activities. In European Mediterranean countries most forest fires are due to human activities. However, lightning is still an important fire ignition source...... in some regions. Integration of lightning and human fire occurrence probability into fire risk indices would be necessary to have a complete picture of the causal agents and their relative importance in fire occurrence. We present two methods for the integration of lightning and human fire occurrence...... probability models at 1 × 1 km grid cell resolution in two regions of Spain: Madrid, which presents a high fire incidence due to human activities; and Aragón, one of the most affected regions in Spain by lightning-fires. For validation, independent fire ignition points were used to compute the Receiver...

  2. Lightning, IT Diffusion and Economic Growth across US States

    DEFF Research Database (Denmark)

    Andersen, Thomas Barnebeck; Bentzen, Jeanet; Dalgaard, Carl-Johan Lars

    Empirically, a higher frequency of lightning strikes is associated with slower growth in labor productivity across the 48 contiguous US states after 1990; before 1990 there is no correlation between growth and lightning. Other climate variables (e.g., temperature, rainfall and tornadoes) do...... not conform to this pattern. A viable explanation is that lightning influences IT diffusion. By causing voltage spikes and dips, a higher frequency of ground strikes leads to damaged digital equipment and thus higher IT user costs. Accordingly, the flash density (strikes per square km per year) should...... adversely affect the speed of IT diffusion. We find that lightning indeed seems to have slowed IT diffusion, conditional on standard controls. Hence, an increasing macroeconomic sensitivity to lightning may be due to the increasing importance of digital technologies for the growth process....

  3. Time domain simulations of preliminary breakdown pulses in natural lightning

    CERN Document Server

    Carlson, B E; Bitzer, P; Christian, H

    2016-01-01

    Lightning discharge is a complicated process with relevant physical scales spanning many orders of magnitude. In an effort to understand the electrodynamics of lightning and connect physical properties of the channel to observed behavior, we construct a simulation of charge and current flow on a narrow conducting channel embedded in three-dimensional space with the time domain electric field integral equation, the method of moments, and the thin-wire approximation. The method includes approximate treatment of resistance evolution due to lightning channel heating and the corona sheath of charge surrounding the lightning channel. Focusing our attention on preliminary breakdown in natural lightning by simulating stepwise channel extension with a simplified geometry, our simulation reproduces the broad features observed in data collected with the Huntsville Alabama Marx Meter Array. Some deviations in pulse shape details are evident, suggesting future work focusing on the detailed properties of the stepping mecha...

  4. Lightning Jump Algorithm and Relation to Thunderstorm Cell Tracking, GLM Proxy and other Meteorological Measurements

    Science.gov (United States)

    Schultz, Christopher J.; Carey, Larry; Cecil, Dan; Bateman, Monte; Stano, Geoffrey; Goodman, Steve

    2012-01-01

    Objective of project is to refine, adapt and demonstrate the Lightning Jump Algorithm (LJA) for transition to GOES -R GLM (Geostationary Lightning Mapper) readiness and to establish a path to operations Ongoing work . reducing risk in GLM lightning proxy, cell tracking, LJA algorithm automation, and data fusion (e.g., radar + lightning).

  5. Observation of Lightning Ball (Ball Lightning): A new phenomenological description of the phenomenon

    CERN Document Server

    Tar, Domokos

    2009-01-01

    The author (physicist)has observed the very strange,beautiful and frightening Lightning Ball (LB). He has never forgotten this phenomenon. During his working life he could not devote himself to the problem of LB-formation.Only two years ago as he has been reading different unbelievable models of LB-formation, he decided to work on this problem. By studying the literature and the crucial points of his observation the author succeeded in creating a completely new model of Lightning Ball(LB) and Ball Lightning(BL)-formation based on the symmetry breaking of the hydrodynamic vortex ring.This agrees fully with the observation and overcomes the shortcomings of current models of LB formation. This model provides answers to the questions: Why are LBs so rarely observed,why do BLs in rare cases have such a high energy and how can we generate LB in the laboratory? Moreover the author differentiates between LB and BL, the latter having a high energy and occuring in 5 % of the observations. Keywords: ball lightning, hydr...

  6. Lightning rod ionizing natural ionca - Ionic electrode active trimetallictriac of grounding - Definitive and total solution against 'blackouts' and electrical faults generated by atmospheric charges (lightning)

    Energy Technology Data Exchange (ETDEWEB)

    Cabareda, Luis

    2010-09-15

    The Natural Ionizing System of Electrical Protection conformed by: Lightning Rod Ionizing Natural Ionca and Ionic Electrode Active Trimetallic Triac of Grounding offers Total Protection, Maximum Security and Zero Risk to Clinics, Hospitals, Integral Diagnostic Center, avoiding ''the burning'' of Electronics Cards; Refineries, Tanks and Stations of Fuel Provision; Electrical Substations, Towers and Transmission Lines with transformer protection, motors, elevators, A/C, mechanicals stairs, portable and cooling equipment, electrical plants, others. This New High Technology is the solution to the paradigm of Benjamin Franklin and it's the mechanism to end the 'Blackouts' that produces so many damages and losses throughout the world.

  7. The Integration of Total Lightning Information Into National Weather Service Operations

    Science.gov (United States)

    Darden, C.; Burks, J.; Bradshaw, T.; Boccippio, D.; Goodman, S.; Blakeslee, R.; McCaul, E.; Buechler, D.; Hall, J.; Bailey, J.

    2003-12-01

    The collocation of a National Weather Service (NWS) Forecast Office with atmospheric scientists from NASA/Marshall Space Flight Center (MSFC) and the University of Alabama in Huntsville (UAH) has afforded a unique opportunity for science sharing and technology transfer. One such technology transfer is the utilization of the North Alabama Lightning Mapping Array (LMA) in daily forecast and warning operations. The LMA consists of ten VHF receivers deployed across northern Alabama and a base station located at the National Space Science and Technology Center (NSSTC) on the UAH campus. Preliminary investigations have shown a strong correlation between the time rate-of-change (trending) of total lightning and changes in intensity/severity of the parent convective cell. It is hoped that through the use of near real-time total lightning information, in conjunction with other remote sensing datasets (radar, satellite, observations), that the forecaster can achieve an even greater level of situational awareness. The primary mission of the NWS is to protect life and property. The utilization of the LMA data may prove to be a vital contributor to this mission by enhancing severe weather warning and decision-making, improving warning lead times, and increasing the probability of detection of severe and hazardous weather. To maximize the use of total lightning information, the LMA data is being ingested in real-time into the NWS Advanced Weather Interactive Processing System (AWIPS) decision support system. The presentation will focus on the collaborative process, technology transfer methodologies and a look to the future. In addition, a brief review of recent LMA case studies will be provided.

  8. On the Relationship between Observed NLDN Lightning Strikes and Modeled Convective Precipitation Rates Parameterization of Lightning NOx Production in CMAQ

    Science.gov (United States)

    Lightning-produced nitrogen oxides (NOX=NO+NO2) in the middle and upper troposphere play an essential role in the production of ozone (O3) and influence the oxidizing capacity of the troposphere. Despite much effort in both observing and modeling lightning NOX during the past dec...

  9. Do cosmic ray air showers initiate lightning?: A statistical analysis of cosmic ray air showers and lightning mapping array data

    Science.gov (United States)

    Hare, B. M.; Dwyer, J. R.; Winner, L. H.; Uman, M. A.; Jordan, D. M.; Kotovsky, D. A.; Caicedo, J. A.; Wilkes, R. A.; Carvalho, F. L.; Pilkey, J. T.; Ngin, T. K.; Gamerota, W. R.; Rassoul, H. K.

    2017-08-01

    It has been argued in the technical literature, and widely reported in the popular press, that cosmic ray air showers (CRASs) can initiate lightning via a mechanism known as relativistic runaway electron avalanche (RREA), where large numbers of high-energy and low-energy electrons can, somehow, cause the local atmosphere in a thundercloud to transition to a conducting state. In response to this claim, other researchers have published simulations showing that the electron density produced by RREA is far too small to be able to affect the conductivity in the cloud sufficiently to initiate lightning. In this paper, we compare 74 days of cosmic ray air shower data collected in north central Florida during 2013-2015, the recorded CRASs having primary energies on the order of 1016 eV to 1018 eV and zenith angles less than 38°, with Lightning Mapping Array (LMA) data, and we show that there is no evidence that the detected cosmic ray air showers initiated lightning. Furthermore, we show that the average probability of any of our detected cosmic ray air showers to initiate a lightning flash can be no more than 5%. If all lightning flashes were initiated by cosmic ray air showers, then about 1.6% of detected CRASs would initiate lightning; therefore, we do not have enough data to exclude the possibility that lightning flashes could be initiated by cosmic ray air showers.

  10. Lightning Location With Single-Station Observation of VLF Spherics

    Science.gov (United States)

    Nagano, I.; Yagitani, S.; Komonmae, H.; Takezono, N.

    2001-12-01

    Most of the lightning location systems recently available require the simultaneous reception of lightning-generated radio pulses (spherics) at multiple stations. In this work, we develop a lightning location system to determine both the direction and range of a lightning stroke with a single-station observation of VLF spherics. The technique used here is a rather classical one, but we try to improve the ranging accuracy by applying sophisticated signal processing techniques, and our final goal is to develop a portable lightning locator. We observe wave forms of two horizontal magnetic fields and one vertical electric field of VLF spherics, each of which usually consists of a couple of sequential pulses. The first pulse comes directly from a lightning return stroke, and is used for the direction finding of the stroke. On the other hand, the second and later pulses are the multiple reflections of the first pulse inside the Earth-ionosphere waveguide. Since the time-of-arrival (ToA) of each pulse is determined by its propagation path length in the waveguide, by using the observed difference in ToA of two or more pulses, we can inversely estimate not only the reflection height at the ionosphere but also the range of the lightning stroke. By installing the developed system at Kanazawa University, we have been observing lightning-generated spherics since April, 2000. Compared with the lightning location data provided by a local power company, preliminary analysis shows that this system can locate each lightning stroke within several hundred km with a sufficient accuracy.

  11. High lightning activity in maritime clouds near Mexico

    Science.gov (United States)

    Kucienska, B.; Raga, G. B.; Romero-Centeno, R.

    2012-09-01

    Lightning activity detected by the World Wide Lightning Location Network (WWLLN) over oceanic regions adjacent to Mexico is often as high as that observed over the continent. In order to explore the possible causes of the observed high flash density over those regions, the relationships between lightning, rainfall, vertical hydrometeor profiles, latent heating, wind variability and aerosol optical depth are analyzed. The characteristics of lightning and precipitation over four oceanic zones adjacent to Mexican coastlines are contrasted against those over the continent. The number of flashes per rainfall over some coastal maritime regions is found to be higher than over the continent. The largest number of flashes per rainfall is observed during the biomass burning season. In addition, we compare two smaller areas of the Tropical Pacific Ocean: one located within the Inter-Tropical Convergence Zone and characterized by high rainfall and weak lightning activity and the other one influenced by a continental wind jet and characterized by high rainfall and strong lightning activity. During the rainy season, the monthly distribution of lightning within the region influenced by the continental wind jet is contrary to that of rainfall. Moreover, the monthly variability of lightning is very similar to the variability of the meridional wind component and it is also related to the variability of aerosol optical depth. The analysis suggests that the high lightning activity observed over coastal Pacific region is linked to the continental cloud condensation nuclei advected over the ocean. Analysis of daily observations indicates that the greatest lightning density is observed for moderate values of the aerosol optical depth, between 0.2 and 0.35.

  12. Extraction of nickel from edible oils with a complexing agent prior to determination by FAAS.

    Science.gov (United States)

    Tokay, Feyzullah; Bağdat, Sema

    2016-04-15

    In the present work, a new extraction method for separation of nickel from edible oils and determination by FAAS is reported. This method is based on extraction of Ni(II) ions from the oil to aqueous phase with N,N'-bis(4-methoxysalicylidene) ethylenediamine (MSE) and determination by FAAS. Properties of the complex formed between MSE and Ni(II) were investigated spectrophotometrically. Central composite design (CCD) was utilized for optimization of MSE to oil, stirring time and temperature, which were 0.97 mL g(-1), 15.4 min, and 29.7°C, respectively. The developed method was tested with an oil-based metal standard and the recovery was 93.8±3.9%. The proposed method was applied with five different edible oils.

  13. Lightning Magnetic Field Measurements around Langmuir Laboratory

    Science.gov (United States)

    Stock, M.; Krehbiel, P. R.; Rison, W.; Aulich, G. D.; Edens, H. E.; Sonnenfeld, R. G.

    2010-12-01

    In the absence of artificial conductors, underground lightning transients are produced by diffusion of the horizontal surface magnetic field of a return stroke vertically downward into the conducting earth. The changing magnetic flux produces an orthogonal horizontal electric field, generating a dispersive, lossy transverse electromagnetic wave that penetrates a hundred meters or more into the ground according to the skin depth of the medium. In turn, the electric field produces currents that flow toward or away from the channel to ground depending on the stroke polarity. The underground transients can produce large radial horizontal potential gradients depending on the distance from the discharge and depth below the surface. In this study we focus on the surface excitation field. The goal of the work is to compare measurements of surface magnetic field waveforms B(t) at different distances from natural lightning discharges with simple and detailed models of the return stroke fields. In addition to providing input to the diffusion mechanism, the results should aid in further understanding return stroke field generation processes. The observational data are to be obtained using orthogonal sets of straightened Rogowski coils to measure magnetic field waveforms in N-S and E-W directions. The waveforms are sampled at 500 kS/s over 1.024 second time intervals and recorded directly onto secure digital cards. The instrument operates off of battery power for several days or weeks at a time in remote, unattended locations and measures magnetic field strengths of up to several tens of amperes/meter. The observations are being made in conjunction with collocated slow electric field change measurements and under good 3-D lightning mapping array (LMA) and fast electric field change coverage.

  14. Detection of lightning in Saturn's Northern Hemisphere

    CERN Document Server

    Moghimi, Mohsen Hassanzadeh

    2012-01-01

    During Cassini flyby of Saturn at a radial distance 6.18R_s (Saturn Radius), a signal was detected from about 200 to 430 Hz that had the proper dispersion characteristics to be a whistler. The frequency-time dispersion of the whistler was found to be 81 Hz1/2s. Based on this dispersion constant, we determined, from a travel time computation, that the whistler must have originated from lightning in the northern hemisphere of Saturn. Using a simple centrifugal potential model consisting of water group ions, and hydrogen ions we also determine the fractional concentration and scale height that gave the best fit to the observed dispersion.

  15. ADSORPTION BEHAVIOUR OF Mn(Ⅱ) AND Zn(Ⅱ) ON ATTAPULGITE WITH FAAS METHOD

    Institute of Scientific and Technical Information of China (English)

    LI Bingbing; LI Chunxiang; LIU Aiqin; XIAO Bo

    2008-01-01

    Active attapulbgite as adsorptive reagent, the adsorptive behavior of Mn(Ⅱ) and Zn(Ⅱ) was studied with Flame atomic absorption spectroscopy (FAAS) method.The mainly factors of influencing the adsorption and desorption of Mn(Ⅱ) and Zn(Ⅱ) were discussed.The interference of coexisting ions was investigated, and the actual sample determination from adzuki beans, mung beans and phosphating waste water was conducted with good result.

  16. ADSORPTION BEHAVIOUR OF Mn(Ⅱ) AND Zn(Ⅱ) ON ATTAPULGITE WITH FAAS METHOD

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Active attapulbgite as adsorptive reagent, the adsorptive behavior of Mn(II) and Zn(II) was studied with Flame atomic absorption spectroscopy (FAAS) method. The mainly factors of influencing the adsorption and desorption of Mn(II) and Zn(II) were discussed. The interference of coexisting ions was investigated, and the actual sample determination from adzuki beans, mung beans and phosphating waste water was conducted with good result.

  17. NextGen Technologies on the FAA's Standard Terminal Automation Replacement System

    Science.gov (United States)

    Witzberger, Kevin; Swenson, Harry; Martin, Lynne; Lin, Melody; Cheng, Jinn-Hwei

    2014-01-01

    This paper describes the integration, evaluation, and results from a high-fidelity human-in-the-loop (HITL) simulation of key NASA Air Traffic Management Technology Demonstration - 1 (ATD- 1) technologies implemented in an enhanced version of the FAA's Standard Terminal Automation Replacement System (STARS) platform. These ATD-1 technologies include: (1) a NASA enhanced version of the FAA's Time-Based Flow Management, (2) a NASA ground-based automation technology known as controller-managed spacing (CMS), and (3) a NASA advanced avionics airborne technology known as flight-deck interval management (FIM). These ATD-1 technologies have been extensively tested in large-scale HITL simulations using general-purpose workstations to study air transportation technologies. These general purpose workstations perform multiple functions and are collectively referred to as the Multi-Aircraft Control System (MACS). Researchers at NASA Ames Research Center and Raytheon collaborated to augment the STARS platform by including CMS and FIM advisory tools to validate the feasibility of integrating these automation enhancements into the current FAA automation infrastructure. NASA Ames acquired three STARS terminal controller workstations, and then integrated the ATD-1 technologies. HITL simulations were conducted to evaluate the ATD-1 technologies when using the STARS platform. These results were compared with the results obtained when the ATD-1 technologies were tested in the MACS environment. Results collected from the numerical data show acceptably minor differences, and, together with the subjective controller questionnaires showing a trend towards preferring STARS, validate the ATD-1/STARS integration.

  18. Radioactive lightning rods: radiologic evaluation and regulatory policy related to its use in Cuba; Pararrayos radiactivos: evaluacion radiologica de su empleo y politica regulatoria com relacion a su utilizacion en Cuba

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Forteza, Yamil; Quevedo Garcia, Jose R.; Diaz Guerra, Pedro I.; Cruz Dumenico, Gonzalez; Fuente Puch, Andres de la [Centro Nacional de Seguridad Nuclear, La Habana (Cuba)

    2001-07-01

    The radioactive lightning rod employment for the protection of facilities against atmospheric discharges reached its maximum splendor in the eighties. It was in fact at the end of this decade when the technical considerations related to the justification of this practice finally conclude that the production of such teams was abolished. For the regulatory authorities, however, it continues having validity the question related to the control of lightning rod still in use as well as the question related to the establishment of a coherent with the international practice national policy. The paper shows the results of the last 10 years of control of the radioactive lightning rod use in Cuba and the radiological evaluation carried out on the base of this experience. Lastly, it exposes the regulatory policy referred to the employment of the radioactive lightning rod in the country. (author)

  19. Lightning prevention risk assessment technology and control measures of Transmission line%输电线路防雷风险评估技术及治理措施

    Institute of Scientific and Technical Information of China (English)

    吴波

    2016-01-01

    Introduce the influence of lightning disturbance on the transmission line, describe the purpose of differential lightning prevention risk assessment and assessment process. Besides, lightning prevention risk assessment and control measures of transmission line were put forward by using application of differential evaluation system. Lightning protection work once again rose to new heights.%介绍雷害对输电线路的影响,描述开展差异化防雷风险评估的目的和评估流程。另外,应用差异化评估系统对输电线路进行防雷风险评估并提出治理措施,使防雷工作更上一个新的台阶。

  20. Sistem Informasi Petir (SIP dengan Metode Lightning Distribution (LD di Wilayah Sumatera Barat

    Directory of Open Access Journals (Sweden)

    Andrew Kurniawan Vadreas

    2014-09-01

    Full Text Available This paper mapped 200 locations of lightning strikes in West Sumatra province. Mapping the location of lightning strikes as part of Lightning Information System was designed with the method of Lightning Distribution (LD. To get the location of lightning strikes obtained from the calculation reflection of ionosphere method to determine the distance of a lightning strike from stations of lightning and methods of Magnetic Direction Finding (MDF to get directions from the lightning strike. Direction data obtained processed to generate a lightning incident location, then that location will be displayed on Google Maps. After that in the process of Lightning Distribution method which is a form of lightning strike density mapping by using the "File Format" grid, where each grid was measured to be 1 x 1 km2 called the Local Density Flash (LFD. If there are multiple point strikes on the grid will change the color that is on the map fit how many number of strikes on the grid which is a Probabilistic computation Flash Density (PFD. The depiction of the scale of danger lightning in the form of variations color changes at the point where the bolt of green color represents the minimum number density of lightning strikes that contains a single point and the red color represents the maximum number density of strikes which contains more than ten points strike. Based on the color distribution of lightning strikes and Payakumbuh Agam area has the highest rate of lightning strikes in the study period.

  1. New lightning current resistant low voltage limiting device for DC railway systems; Neue blitzstromtragfaehige Niederspannungsbegrenzungseinrichtung zum Potenzialschutz von Gleichstrombahnsystemen

    Energy Technology Data Exchange (ETDEWEB)

    Rocks, A.; Hinrichsen, V. [Technische Univ. Darmstadt (Germany). Fachgebiet Hochspannungstechnik; Richter, B. [ABB Schweiz AG, Wettingen (Switzerland); Zayer, H. [ESN Bahngeraete GmbH, Mannheim (Germany)

    2007-07-01

    In dc railway systems, low voltage limiters are applied to limit potential rises in case of failures by forming a permanent short-circuit between return circuit and Earth. These devices can usually carry only moderate lightning currents without permanent failure. In this contribution, a new concept is introduced which provides personal as well as equipment protection by combining a surge arrester and a low voltage limiter in a suited way. (orig.)

  2. Beijing Lightning Network (BLNET): Configuration, Function and Preliminary Results

    Science.gov (United States)

    Qie, X.; Wang, D.; Wang, Y.; Liu, M.; Tian, Y.; Lu, G.

    2015-12-01

    A regional multi-frequency-band lightning detection network in Beijing (BLNET) has been developed for both research and operational purposes. The network is employed in the experiment of Dynamic-microphysical-electrical Processes in Severe Thunderstorms and Lightning Hazards (Storm973), supported by Ministry of Science and Technology as National Key Basic Research Program of China or 973 Program. The network consisted of 16 stations in 2015 covering most part of The "Jing-Jin-Ji" (Beijing-Tianjin-Hebei) metropolis zone, one of the most developed areas in China. Four different sensors, including slow antenna, fast antenna, magnetic antenna, and VHF antenna, are integrated in each station to detect lightning radiation signals in different frequency band. The Chan algorithm and Levenberg-Marquardt method are adopted jointly in the lightning location algorithm. In addition to locate the lightning radiation pulses in two-dimension or three-dimension in different band, the charge source neutralized by the lightning discharge can be retrieved either. The theoretical horizontal error over the network is less than 200 m and the vertical error is less than 500 m over the network. The comparison of total lightning location results with corresponding radar echoes for thunderstorm cases indicates the good performance of BLNET in the severe convection surveillance. The actual two-dimensional location error in VLF/LF band, compared with a ground truth that acquired with a GPS-synchronized high-speed video camera, is about 250 m.

  3. Extensive air showers, lightning, and thunderstorm ground enhancements

    Science.gov (United States)

    Chilingarian, A.; Hovsepyan, G.; Kozliner, L.

    2016-09-01

    For lightning research, we monitor particle fluxes from thunderclouds, the so-called thunderstorm ground enhancements (TGEs) initiated by runaway electrons, and extensive air showers (EASs) originating from high-energy protons or fully stripped nuclei that enter the Earth's atmosphere. We also monitor the near-surface electric field and atmospheric discharges using a network of electric field mills. The Aragats "electron accelerator" produced several TGEs and lightning events in the spring of 2015. Using 1-s time series, we investigated the relationship between lightning and particle fluxes. Lightning flashes often terminated the particle flux; in particular, during some TGEs, lightning events would terminate the particle flux thrice after successive recovery. It was postulated that a lightning terminates a particle flux mostly in the beginning of a TGE or in its decay phase; however, we observed two events (19 October 2013 and 20 April 2015) when the huge particle flux was terminated just at the peak of its development. We discuss the possibility of a huge EAS facilitating lightning leader to find its path to the ground.

  4. Lightning flash density in relation to aerosol over Nanjing (China)

    Science.gov (United States)

    Tan, Y. B.; Peng, L.; Shi, Z.; Chen, H. R.

    2016-06-01

    Time series data of lightning flash density, aerosol optical depth (AOD), surface temperature, convective available potential energy (CAPE) and thunderstorm days for 10 years (2002-2011), cloud-to-ground lightning (CG), and AOD of 5 years for summer season, i.e., June, July, and August over Nanjing, China, have been analyzed, to investigate the impact of aerosols on lightning. The results indicate that the radiative effect of aerosol may be one of the main reason for the decrease of the lightning flash density in a long period, while the aerosol microphysical effect may be a major role in the increase of the percent of + CG flashes (P+ CG). The dependence of surface temperature, CAPE, and thunderstorm days on AOD (R = - 0.748, - 0.741, - 0.744), and the negative correlation (R = - 0.634) between lightning flash density and AOD may lend support for the radiative effect of aerosol on lightning. In addition, elevated aerosols may change the charge distribution in thundercloud, hence enhancing the positive cloud-to-ground lightning (+ CG) activity, as P+ CG is positively correlated with AOD.

  5. Simulating lightning into the RAMS model: implementation and preliminary results

    Directory of Open Access Journals (Sweden)

    S. Federico

    2014-05-01

    Full Text Available This paper shows the results of a tailored version of a previously published methodology, designed to simulate lightning activity, implemented into the Regional Atmospheric Modeling System (RAMS. The method gives the flash density at the resolution of the RAMS grid-scale allowing for a detailed analysis of the evolution of simulated lightning activity. The system is applied in detail to two case studies occurred over the Lazio Region, in Central Italy. Simulations are compared with the lightning activity detected by the LINET network. The cases refer to two thunderstorms of different intensity. Results show that the model predicts reasonably well both cases and that the lightning activity is well reproduced especially for the most intense case. However, there are errors in timing and positioning of the convection, whose magnitude depends on the case study, which mirrors in timing and positioning errors of the lightning distribution. To assess objectively the performance of the methodology, standard scores are presented for four additional case studies. Scores show the ability of the methodology to simulate the daily lightning activity for different spatial scales and for two different minimum thresholds of flash number density. The performance decreases at finer spatial scales and for higher thresholds. The comparison of simulated and observed lighting activity is an immediate and powerful tool to assess the model ability to reproduce the intensity and the evolution of the convection. This shows the importance of the use of computationally efficient lightning schemes, such as the one described in this paper, in forecast models.

  6. A Lightning Channel Retrieval Algorithm for the North Alabama Lightning Mapping Array (LMA)

    Science.gov (United States)

    Koshak, William; Arnold, James E. (Technical Monitor)

    2002-01-01

    A new multi-station VHF time-of-arrival (TOA) antenna network is, at the time of this writing, coming on-line in Northern Alabama. The network, called the Lightning Mapping Array (LMA), employs GPS timing and detects VHF radiation from discrete segments (effectively point emitters) that comprise the channel of lightning strokes within cloud and ground flashes. The network will support on-going ground validation activities of the low Earth orbiting Lightning Imaging Sensor (LIS) satellite developed at NASA Marshall Space Flight Center (MSFC) in Huntsville, Alabama. It will also provide for many interesting and detailed studies of the distribution and evolution of thunderstorms and lightning in the Tennessee Valley, and will offer many interesting comparisons with other meteorological/geophysical wets associated with lightning and thunderstorms. In order to take full advantage of these benefits, it is essential that the LMA channel mapping accuracy (in both space and time) be fully characterized and optimized. In this study, a new revised channel mapping retrieval algorithm is introduced. The algorithm is an extension of earlier work provided in Koshak and Solakiewicz (1996) in the analysis of the NASA Kennedy Space Center (KSC) Lightning Detection and Ranging (LDAR) system. As in the 1996 study, direct algebraic solutions are obtained by inverting a simple linear system of equations, thereby making computer searches through a multi-dimensional parameter domain of a Chi-Squared function unnecessary. However, the new algorithm is developed completely in spherical Earth-centered coordinates (longitude, latitude, altitude), rather than in the (x, y, z) cartesian coordinates employed in the 1996 study. Hence, no mathematical transformations from (x, y, z) into spherical coordinates are required (such transformations involve more numerical error propagation, more computer program coding, and slightly more CPU computing time). The new algorithm also has a more realistic

  7. Lightning in hybrid cable-overhead lines and consequent transient overvoltages

    DEFF Research Database (Denmark)

    Silva, Filipe Miguel Faria da; Schultz Pedersen, Kasper; Bak, Claus Leth

    2017-01-01

    Whereas lines that consist entirely of underground cable are naturally protected from lightning, the phenomenon must be considered for lines that are a mix of overhead lines and underground cables. The difference between overhead lines and underground cables wave impedances may lead to transient...... overvoltages caused by reflections at the transitions points. This paper explains the phenomenon and analyses the influence of modelling Corona effect, the grounding of the towers and of the cable’s screen on the overvoltage magnitude. The analysis is made both for direct strokes on the overhead line phase......, Transient Overvoltages...

  8. Lightning and radar observations of hurricane Rita landfall

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, Bradley G [Los Alamos National Laboratory; Suszcynsky, David M [Los Alamos National Laboratory; Hamlin, Timothy E [Los Alamos National Laboratory; Jeffery, C A [Los Alamos National Laboratory; Wiens, Kyle C [TEXAS TECH U.; Orville, R E [TEXAS A& M

    2009-01-01

    Los Alamos National Laboratory (LANL) owns and operates an array of Very-Low Frequency (VLF) sensors that measure the Radio-Frequency (RF) waveforms emitted by Cloud-to-Ground (CG) and InCloud (IC) lightning. This array, the Los Alamos Sferic Array (LASA), has approximately 15 sensors concentrated in the Great Plains and Florida, which detect electric field changes in a bandwidth from 200 Hz to 500 kHz (Smith et al., 2002). Recently, LANL has begun development of a new dual-band RF sensor array that includes the Very-High Frequency (VHF) band as well as the VLF. Whereas VLF lightning emissions can be used to deduce physical parameters such as lightning type and peak current, VHF emissions can be used to perform precise 3d mapping of individual radiation sources, which can number in the thousands for a typical CG flash. These new dual-band sensors will be used to monitor lightning activity in hurricanes in an effort to better predict intensification cycles. Although the new LANL dual-band array is not yet operational, we have begun initial work utilizing both VLF and VHF lightning data to monitor hurricane evolution. In this paper, we present the temporal evolution of Rita's landfall using VLF and VHF lightning data, and also WSR-88D radar. At landfall, Rita's northern eyewall experienced strong updrafts and significant lightning activity that appear to mark a transition between oceanic hurricane dynamics and continental thunderstorm dynamics. In section 2, we give a brief overview of Hurricane Rita, including its development as a hurricane and its lightning history. In the following section, we present WSR-88D data of Rita's landfall, including reflectivity images and temporal variation. In section 4, we present both VHF and VLF lightning data, overplotted on radar reflectivity images. Finally, we discuss our observations, including a comparison to previous studies and a brief conclusion.

  9. Near ground gamma radiation associated with lightning

    Science.gov (United States)

    Sakuma, K.; Greenfield, M. B.; Ikeda, Y.; Kubo, K.

    2004-03-01

    Increases in the atmospheric gamma radiation of 22 to 82above normal background have been observed after the onset of lightning fifteen times since March 2001[1]. Gamma rays have been observed with up to four 12.9 cm3 NaI detectors and recently with a high resolution Ge detector positioned 6-21 m and 15 m above ground, respectively. The tail of the observed background subtracted gamma ray rates GRR were fitted with exponential decay curves yielding typical correlation coefficients of 0.95 to 0.99 and half-lives of 52.7 +/-4.81 min and 52.8+/-10.95 min, without and with precipitation, respectively. The GRR above 300 KeV from radon progeny due to precipitation were subtracted [2]. The 3x3 Ge detector with 2 KeV resolution positioned about 2 m from one of the NaI detectors observed increases in GRR minutes after the onset of lightning with a delayed 50 min exponential decay which was concurrently observed in the NaI detector. [1] M. B. Greenfield et al., Journal of Applied Physics 93 no. 3 (2003) pp 1839-1844. [2] M. B. Greenfield et al., Journal of Applied Physics 93 no. 9 (2003) pp 5733-5741.

  10. Fast radio bursts as pulsar lightning

    Science.gov (United States)

    Katz, J. I.

    2017-07-01

    There are striking phenomenological similarities between fast radio bursts (FRBs) and lightning in the Earth's and planetary atmospheres. Both have very low duty factors, ≲10-8-10-5 for FRBs and (very roughly) ˜10-4 for the main return strokes in an active thundercloud. Lightning occurs in an electrified insulating atmosphere when a conducting path is created by and permits current flow. FRBs may occur in neutron star magnetospheres whose plasma is believed to be divided by vacuum gaps. Vacuum is a perfect insulator unless electric fields are sufficient for electron-positron pair production by curvature radiation, a high-energy analogue of electrostatic breakdown in an insulating gas. FRB may be 'electrars' powered by the release of stored electrostatic energy, counterparts to soft gamma repeaters powered by the release of stored magnetostatic energy (magnetars). This frees pulsar FRB models from the constraint that their power not exceeds the instantaneous spin-down power. Energetic constraints imply that the sources of more energetic FRBs have shorter spin-down lifetimes, perhaps even less than the 3 yr over which FRB 121102 has been observed to repeat.

  11. Magnetotelluric distortions directly observed with lightning data

    Science.gov (United States)

    Hennessy, Lachlan; Macnae, James

    2017-08-01

    Galvanic distortions complicate magnetotelluric (MT) soundings. In this research, we use lightning network data to identify specific sferics in MT measurements and analyse these events on the basis of the lightning source location. Without source information, identification and removal of galvanic distortion is a fundamentally ill-posed problem, unless data are statistically decomposed into determinable and indeterminable parts. We use realistic assumptions of the earth-ionosphere waveguide propagation velocity to accurately predict the time of arrival, azimuth and amplitude for every significant sferic in our time-series data. For each sferic with large amplitude, we calculate the rotation of the electric field from the measured to the predicted arrival azimuth. This rotation of the electric field is a primary parameter of distortion. Our results demonstrate that a rudimentary model for near-surface galvanic distortion consistently fits observed electric field rotations. When local features rotate regional electric fields, then counter-rotating data to predicted arrival azimuths should correct the directional dependence of static shift. Although we used amplitude thresholds to simplify statistical processing, future developments should incorporate both signal-to-noise improvements and multisite decompositions. Lower amplitude signal may also be useful after the appropriate signal processing for noise reduction. We anticipate our approach will be useful for further work on MT distortion.

  12. 雷电电磁脉冲(LEMP)的特性分析及屏蔽%Characteristic Analysis and Shielding of Lightning Electromagnetism Impulse

    Institute of Scientific and Technical Information of China (English)

    王庆祥; 姚烨; 崔喆; 孙冬迪; 薛文安

    2014-01-01

    This paper discusses the dangers of lightning electromagnetic pulses, including surges conduction, electromagnetic radiation, and induced voltage. Then it analyzes the characteristics of lightning electromagnetic pulses. Finally, it introduces lightning electromagnetic pulse protection, mainly magnetic shielding, as well as the selection of magnetic shielding material.%本文讨论了雷电电磁脉冲的危害,包括传导浪涌、辐射电磁场、感应电压,分析雷电电磁脉冲的特性;并以磁屏蔽为主介绍雷电电磁脉冲的防护,以及磁屏蔽材料的选择。

  13. Transcranial stimulability of phosphenes by long lightning electromagnetic pulses

    CERN Document Server

    Peer, J

    2010-01-01

    The electromagnetic pulses of rare long (order of seconds) repetitive lightning discharges near strike point (order of 100m) are analyzed and compared to magnetic fields applied in standard clinical transcranial magnetic stimulation (TMS) practice. It is shown that the time-varying lightning magnetic fields and locally induced potentials are in the same order of magnitude and frequency as those established in TMS experiments to study stimulated perception phenomena, like magnetophosphenes. Lightning electromagnetic pulse induced transcranial magnetic stimulation of phosphenes in the visual cortex is concluded to be a plausible interpretation of a large class of reports on luminous perceptions during thunderstorms.

  14. Transcranial stimulability of phosphenes by long lightning electromagnetic pulses

    Energy Technology Data Exchange (ETDEWEB)

    Peer, J. [Institut fuer Ionenphysik und Angewandte Physik, Universitaet Innsbruck, A-6020 Innsbruck (Austria); Kendl, A., E-mail: alexander.kendl@uibk.ac.a [Institut fuer Ionenphysik und Angewandte Physik, Universitaet Innsbruck, A-6020 Innsbruck (Austria)

    2010-06-28

    The electromagnetic pulses of rare long (order of seconds) repetitive lightning discharges near strike point (order of 100 m) are analyzed and compared to magnetic fields applied in standard clinical transcranial magnetic stimulation (TMS) practice. It is shown that the time-varying lightning magnetic fields and locally induced electric fields are in the same order of magnitude and frequency as those established in TMS experiments to study stimulated perception phenomena, like magnetophosphenes. Lightning electromagnetic pulse induced transcranial magnetic stimulation of phosphenes in the visual cortex is concluded to be a plausible interpretation of a large class of reports on luminous perceptions during thunderstorms.

  15. Airborne Laser Scanning Quantification of Disturbances from Hurricanes and Lightning Strikes to Mangrove Forests in Everglades National Park, USA

    Directory of Open Access Journals (Sweden)

    Kevin Whelan

    2008-04-01

    Full Text Available Airborne light detection and ranging (LIDAR measurements derived before and after Hurricanes Katrina and Wilma (2005 were used to quantify the impact of hurricanes and lightning strikes on the mangrove forest at two sites in Everglades National Park (ENP. Analysis of LIDAR measurements covering 61 and 68 ha areas of mangrove forest at the Shark River and Broad River sites showed that the proportion of high tree canopy detected by the LIDAR after the 2005 hurricane season decreased significantly due to defoliation and breakage of branches and trunks, while the proportion of low canopy and the ground increased drastically. Tall mangrove forests distant from tidal creeks suffered more damage than lower mangrove forests adjacent to the tidal creeks. The hurricanes created numerous canopy gaps, and the number of gaps per square kilometer increased from about 400~500 to 4000 after Katrina and Wilma. The total area of gaps in the forest increased from about 1~2% of the total forest area to 12%. The relative contribution of hurricanes to mangrove forest disturbance in ENP is at least 2 times more than that from lightning strikes. However, hurricanes and lightning strikes disturb the mangrove forest in a related way. Most seedlings in lightning gaps survived the hurricane impact due to the protection of trees surrounding the gaps, and therefore provide an important resource for forest recovery after the hurricane. This research demonstrated that LIDAR is an effective remote sensing tool to quantify the effects of disturbances such as hurricanes and lightning strikes in the mangrove forest.

  16. Lightning arrester models enabling highly accurate lightning surge analysis; Koseidona kaminari surge kaiseki wo kano ni suru hiraiki model

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, T. [Chubu Electric Power Co. Inc., Nagoya (Japan); Funabashi, T.; Hagiwara, T.; Watanabe, H. [Meidensha Corp., Tokyo (Japan)

    1998-12-28

    Introduced herein are a dynamic behavior model for lightning arresters designed for power stations and substations and a flashover model for a lightning arresting device designed for transmission, both developed by the author et al. The author et al base their zinc oxide type lightning arrester model on the conventional static V-I characteristics, and supplement them with difference in voltage between static and dynamic characteristics. The model is easily simulated using EMTP (Electromagnetic Transients Program) etc. There is good agreement between the results of calculation performed using this model and actually measured values. Lightning arresting devices for transmission have come into practical use, and their effectiveness is introduced on various occasions. For the proper application of such devices, an analysis model capable of faithfully describing the flashover characteristics of arcing horns installed in great numbers along transmission lines, and of lightning arresting devices for transmission, are required. The author et al have newly developed a flashover model for the devices and uses the model for the analysis of lightning surges. It is found that the actually measured values of discharge characteristics of lightning arresting devices for transmission agree well with the values calculated by use of the model. (NEDO)

  17. A brief review of the problem of lightning initiation and a hypothesis of initial lightning leader formation

    Science.gov (United States)

    Petersen, Danyal; Bailey, Matthew; Beasley, William H.; Hallett, John

    2008-09-01

    A brief review of hypothesized mechanisms of lightning initiation is presented, with the suggestion that these mechanisms provide an incomplete picture of lightning initiation. This is followed by two ideas: (1) a combination of previously hypothesized lightning initiation mechanisms as a means for local intensification of the thundercloud electric field, and (2) a process for the formation of a hot lightning leader channel that is analogous to the space leader phase of the laboratory negative stepped leader. Thundercloud electric field observations have consistently yielded peak values that are an order of magnitude weaker than the dielectric strength of air. Various mechanisms have been proposed to explain how lightning can initiate in such weak electric fields, including hydrometeor-initiated positive streamers and cosmic ray-initiated runaway breakdown. The historically favored positive streamer mechanisms are problematic due to requiring electric fields two to three times larger than peak observed fields. The recently favored runaway breakdown mechanisms appear capable of developing in conditions comparable to peak observed fields although it is not clear how these diffuse discharges can lead to creation of a lightning leader. This paper proposes a solution whereby runaway breakdown and hydrometeor-initiated positive streamer systems serve to locally intensify the electric field. Following this local field intensification, it is hypothesized that formation of the initial lightning leader channel is analogous to the formation of a space leader in a laboratory negative stepped leader.

  18. Study on Impulse Current of Low-voltage Systems Initiated by Lightning Stroke%雷击引发低压系统冲击电流研究

    Institute of Scientific and Technical Information of China (English)

    洪友白

    2014-01-01

    以IEC标准和GB 50054-2010《建筑物防雷设计规范》为指导,从雷击损害源、雷击损害类型、雷击电磁脉冲、雷击电涌电流、冲击电流、最大冲击电流入手,逐步深入研究低压系统雷击冲击电流发生的种种情况,进而推断最大冲击电流的起因,作出“雷击建筑物时引发低压系统的最大冲击电流缘于电气系统与防雷系统‘共地’,应在最靠近引来线路入户处安装Ⅰ级试验的SPD”的重要结论及与此结论紧密相关的三条重要推论。%IEC standard and GB 50054 - 2010 Code for Design Protection of Structures against Lightning are used as a guidance to gradually and deeply study various occurrences of lightning impulse current of low-voltage systems via damage sources, damage types, lightning electromagnetic impulse, lightning surge current, impulse current, maximum impulse current. An important conclusion that “the maximum impulse current of the low-voltage systems when the lightning strikes buildings is caused due to‘common ground’ of an electrical system and a lightning protection system, so Class I test SPD shall be set at an entrance closest to the lead-in line” is presented. And three important inferences closely related to the conclusion of this paper are also presented.

  19. The NASA Lightning Nitrogen Oxides Model (LNOM): Application to Air Quality Modeling

    Science.gov (United States)

    Koshak, William; Peterson, Harold; Khan, Maudood; Biazar, Arastoo; Wang, Lihua

    2011-01-01

    Recent improvements to the NASA Marshall Space Flight Center Lightning Nitrogen Oxides Model (LNOM) and its application to the Community Multiscale Air Quality (CMAQ) modeling system are discussed. The LNOM analyzes Lightning Mapping Array (LMA) and National Lightning Detection Network(TradeMark)(NLDN) data to estimate the raw (i.e., unmixed and otherwise environmentally unmodified) vertical profile of lightning NO(x) (= NO + NO2). The latest LNOM estimates of lightning channel length distributions, lightning 1-m segment altitude distributions, and the vertical profile of lightning NO(x) are presented. The primary improvement to the LNOM is the inclusion of non-return stroke lightning NOx production due to: (1) hot core stepped and dart leaders, (2) stepped leader corona sheath, K-changes, continuing currents, and M-components. The impact of including LNOM-estimates of lightning NO(x) for an August 2006 run of CMAQ is discussed.

  20. Lightning related fatalities in livestock: veterinary expertise and the added value of lightning location data.

    Science.gov (United States)

    Vanneste, E; Weyens, P; Poelman, D R; Chiers, K; Deprez, P; Pardon, B

    2015-01-01

    Although lightning strike is an important cause of sudden death in livestock on pasture and among the main reasons why insurance companies consult an expert veterinarian, scientific information on this subject is limited. The aim of the present study was to provide objective information on the circumstantial evidence and pathological findings in lightning related fatalities (LRF), based on a retrospective analysis of 410 declarations, examined by a single expert veterinarian in Flanders, Belgium, from 1998 to 2012. Predictive logistic models for compatibility with LRF were constructed based on anamnestic, environmental and pathological factors. In addition, the added value of lightning location data (LLD) was evaluated. Pathognomonic singe lesions were present in 84/194 (43%) confirmed reports. Factors which remained significantly associated with LRF in the multivariable model were age, presence of a tree or open water in the near surroundings, tympany and presence of feed in the oral cavity at the time of investigation. This basic model had a sensitivity (Se) of 53.8% and a specificity (Sp) of 88.2%. Relying only on LLD to confirm LRF in livestock resulted in a high Se (91.3%), but a low Sp (41.2%), leading to a high probability that a negative case would be wrongly accepted as an LRF. The best results were obtained when combining the model based on the veterinary expert investigation (circumstantial evidence and pathological findings), together with the detection of cloud-to-ground (CG) lightning at the time and location of death (Se 89.1%; Sp 66.7%). Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Using lightning locating system based on time-of-arrival technique to study three-dimensional lightning discharge processes

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A time-of-arrival(TOA) system based on GPS technology for locating VHF radiation sources from lightning has been developed and used in observation sites in the northern Shandong Province,China.The 3D images of the lightning progression have been obtained successfully for the first time in China.The 3D-channel evolutions of typical negative CG,positive CG and IC lightning flashes have been discussed together with the data of fast electric field change.It was found that significant differences existed between the negative and positive CG lightning flashes in terms of the initiation and propagation of the radiation sources.The preliminary breakdown of a negative CG lightning flash propagated at a speed about 5.2×104 m/s.The stepped leader of negative CG lightning flashes was trigged by negative initial breakdown.Thereafter,it propagated downward at a speed of 1.3×105 m/s.The initial process of the positive CG lightning flashes was also a propagation process of negative streamer.These streamers propagated dominantly horizontally in the positive charge region and accumulated positive charges at the origin of the lightning,and as a consequence,initiated downward positive streamers.A new type of lightning discharge that was triggered by a narrow bipolar pulse(NBP) is discussed in this study.The NBP was originated at altitude of about 10.5 km in the upper positive charge region.As a distinct difference from normal IC flash,its channels extended horizontally all around and produced a lot of radiation sources.The source power of the NBP could approach 16.7 kW,which is much greater than that of normal lightning discharge ranging between 100 mW and 500 W.The 3D propagation of this new type of lightning discharge was observed and obtained for the first time in China.The possible initiation mechanism of this new type of light-ning is discussed here.

  2. Simulation of quasi-linear mesoscale convective systems in northern China: Lightning activities and storm structure

    Science.gov (United States)

    Li, Wanli; Qie, Xiushu; Fu, Shenming; Su, Debin; Shen, Yonghai

    2016-01-01

    Two intense quasi-linear mesoscale convective systems (QLMCSs) in northern China were simulated using the WRF (Weather Research and Forecasting) model and the 3D-Var (three-dimensional variational) analysis system of the ARPS (Advanced Regional Prediction System) model. A new method in which the lightning density is calculated using both the precipitation and non-precipitation ice mass was developed to reveal the relationship between the lightning activities and QLMCS structures. Results indicate that, compared with calculating the results using two previous methods, the lightning density calculated using the new method presented in this study is in better accordance with observations. Based on the calculated lightning densities using the new method, it was found that most lightning activity was initiated on the right side and at the front of the QLMCSs, where the surface wind field converged intensely. The CAPE was much stronger ahead of the southeastward progressing QLMCS than to the back it, and their lightning events mainly occurred in regions with a large gradient of CAPE. Comparisons between lightning and non-lightning regions indicated that lightning regions featured more intense ascending motion than non-lightning regions; the vertical ranges of maximum reflectivity between lightning and non-lightning regions were very different; and the ice mixing ratio featured no significant differences between the lightning and non-lightning regions.

  3. 75 FR 8001 - Airworthiness Directives; Hawker Beechcraft Corporation (Type Certificate No. A00010WI Previously...

    Science.gov (United States)

    2010-02-23

    ... gap wiring. This proposed AD would also require you to rework the wiring as necessary to achieve the... rework as necessary to achieve the required lightning strike/surge protection. FAA's Determination and... rework the wiring as necessary to achieve the required lightning strike/surge protection. Costs...

  4. Spatially adaptive probabilistic computation of a sub-kilometre resolution lightning climatology for New Zealand

    Science.gov (United States)

    Etherington, Thomas R.; Perry, George L. W.

    2017-01-01

    Lightning is a key component of the Earth's atmosphere and climate systems, and there is a potential positive feedback between a warming climate and increased lightning activity. In the biosphere, lightning is important as the main natural ignition source for wildfires and because of its contribution to the nitrogen cycle. Therefore, it is important to develop lightning climatologies to characterise and monitor lightning activity. While traditional methods for constructing lightning climatologies are suitable for examining lightning's influence on atmospheric processes, they are less well suited for examining questions about biosphere-lightning interactions. For example, examining the interaction between lightning and wildfires requires linking atmospheric processes to finer scale terrestrial processes and patterns. Most wildfires ignited by lightning are less than one hectare in size, and so require lightning climatologies at a comparable spatial resolution. However, such high resolution lightning climatologies cannot be derived using the traditional cell-count methodology. Here we present a novel geocomputational approach for analysing lightning data at high spatial resolutions. Our approach is based on probabilistic computational methods and is capable of producing a sub-kilometre lightning climatology that honours the spatial accuracy of the strike locations and is adaptive to underlying spatial patterns. We demonstrate our methods by applying them to the mid-latitude oceanic landmass of New Zealand, an area with geographic conditions that are under-represented in existing lightning climatologies. Our resulting lightning climatology has unparalleled spatial resolution, and the spatial and temporal patterns we observe in it are consistent with other continental and tropical lightning climatologies. To encourage further use and development of our probabilistic approach, we provide Python scripts that demonstrate the method alongside our resulting New Zealand

  5. Lightning and middle atmospheric discharges in the atmosphere

    Science.gov (United States)

    Siingh, Devendraa; Singh, R. P.; Kumar, Sarvan; Dharmaraj, T.; Singh, Abhay K.; Singh, Ashok K.; Patil, M. N.; Singh, Shubha

    2015-11-01

    Recent development in lightning discharges including transient luminous events (TLEs) and global electric circuit are discussed. Role of solar activity, convective available potential energy, surface temperature and difference of land-ocean surfaces on convection process are discussed. Different processes of discharge initiation are discussed. Events like sprites and halos are caused by the upward quasi-electrostatic fields associated with intense cloud-to-ground discharges while jets (blue starter, blue jet, gigantic jet) are caused by charge imbalance in thunderstorm during lightning discharges but they are not associated with a particular discharge flash. Elves are generated by the electromagnetic pulse radiated during lightning discharges. The present understanding of global electric circuit is also reviewed. Relation between lightning activity/global electric circuit and climate is discussed.

  6. A Probabilistic, Facility-Centric Approach to Lightning Strike Location

    Science.gov (United States)

    Huddleston, Lisa L.; Roeder, William p.; Merceret, Francis J.

    2012-01-01

    A new probabilistic facility-centric approach to lightning strike location has been developed. This process uses the bivariate Gaussian distribution of probability density provided by the current lightning location error ellipse for the most likely location of a lightning stroke and integrates it to determine the probability that the stroke is inside any specified radius of any location, even if that location is not centered on or even with the location error ellipse. This technique is adapted from a method of calculating the probability of debris collisionith spacecraft. Such a technique is important in spaceport processing activities because it allows engineers to quantify the risk of induced current damage to critical electronics due to nearby lightning strokes. This technique was tested extensively and is now in use by space launch organizations at Kennedy Space Center and Cape Canaveral Air Force Station. Future applications could include forensic meteorology.

  7. A Simple Lightning Assimilation Technique For Improving Retrospective WRF Simulations

    Science.gov (United States)

    Convective rainfall is often a large source of error in retrospective modeling applications. In particular, positive rainfall biases commonly exist during summer months due to overactive convective parameterizations. In this study, lightning assimilation was applied in the Kain...

  8. Effects of Lightning Injection on Power-MOSFETs

    Data.gov (United States)

    National Aeronautics and Space Administration — Lightning induced damage is one of the major concerns in aircraft health monitoring. Such short-duration high voltages can cause significant damage to electronic...

  9. An unusual case of late ocular changes after lightning injury.

    Directory of Open Access Journals (Sweden)

    Datta Himadri

    2002-01-01

    Full Text Available We describe a case of late ocular changes after lightning injury. One year after the injury, complete ankyloblepharon, severe dry eye, corneal opacity, healed iritis and mature cataracts were noted in both eyes of the patient.

  10. A simple lightning assimilation technique for improving retrospective WRF simulations.

    Science.gov (United States)

    Convective rainfall is often a large source of error in retrospective modeling applications. In particular, positive rainfall biases commonly exist during summer months due to overactive convective parameterizations. In this study, lightning assimilation was applied in the Kain-F...

  11. Convective Induced Turbulence (CIT) Detection via Total Lightning Sensing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We proposes to build a prototype Convective-Induced Turbulence (CIT) hazard detection system based on total lightning sensing as an indicator of the location and...

  12. Challenge of lightning detection with LAC on board Akatsuki spacecraft

    Science.gov (United States)

    Takahashi, Yukihiro; Sato, Mitsutero; Imai, Masataka; Yair, Yoav; Fischer, Georg; Aplin, Karen

    2016-04-01

    Even after extensive investigations with spacecraft and ground-based observations, there is still no consensus on the existence of lightning in Venus. It has been reported that the magnetometer on board Venus Express detected whistler mode waves whose source could be lightning discharge occurring well below the spacecraft. On the other hand, with an infrared sensor, VIRTIS of Venus Express, does not show the positive indication of lightning flashes. In order to identify the optical flashes caused by electrical discharge in the atmosphere of Venus, at least, with an optical intensity of 1/10 of the average lightning in the Earth, we built a high-speed optical detector, LAC (Lightning and Airglow Camera), on board Akatsuki spacecraft. The unique performance of the LAC compared to other instruments is the high-speed sampling rate at 32 us interval for all 32 pixels, enabling us to distinguish the optical lightning flash from other pulsing noises. Though, unfortunately, the first attempt of the insertion of Akatsuki into the orbit around Venus failed in December 2010, the second one carried out in December 7 in 2015 was quite successful. We checked out the condition of the LAC on January 5, 2016, and it is healthy as in 2010. Due to some elongated orbit than that planned originally, we have umbra for ~30 min to observe the lightning flash in the night side of Venus every ~10 days, starting on April 2016. Here we would report the instrumental status of LAC and the preliminary results of the first attempt to observe optical lightning emissions.

  13. Usage of Lightning Arrester Line to Feed Light Electrical Loads

    Directory of Open Access Journals (Sweden)

    Hani B. Odeh

    2009-01-01

    Full Text Available In remote areas, light loads (tens of kilowatts are scattered and situated in the field of high voltage lines (66KV and above. These loads are very far from the main feeders/sub-stations (33KV-0.380KV. Feeding such loads in the traditional ways like provision of Diesel-Powered Stations, installation of new distribution lines from the Feeding Centers, or building new Sub-Stations are not practical ways from the economical point of view, because it requires huge additional expenses and will increase electrical power losses. These expenses are not worthy for such loads and therefore, it is necessary to search for other methods to supply them. One of these methods is to use the lightning arrester line as capacitive divider to supply the light loads. In this research, the induced voltage of the lightning arrester line was calculated when it is isolated from the earth. We found the capacitance between lightning arrester line versus the phases and lightning arrester. It was also found the selective power out of the lightning arrester line and the required length which is to be isolated from the earth keeping the main function of the lightning arrester line. When economically comparing between supplying the light electrical loads by traditional ways and the method of lightning arrester, it was found the advantage of using lightning arresters to supply such loads. Also, by using the traditional methods, it was noted that there is a power loss in the power transmission lines by a percentage of 1.8%.

  14. Reliability of lightning resistant overhead distribution lines

    Energy Technology Data Exchange (ETDEWEB)

    Tolbert, L.M.; Cleveland, J.T.; Degenhardt, L.J.

    1995-04-01

    An assessment of the 32 year historical reliability of the 13.8 kV electrical distribution system at the Oak Ridge National Laboratory (ORNL) in Tennessee has yielded several conclusions useful In the planning of Industrial power Systems. The system configuration at ORNL has essentially remained unchanged in the last 32 years which allows a meaningful comparison of reliability trends for the plant`s eight overhead distribution lines, two of which were built in the 1960`s with lightning resistant construction techniques. Meticulous records indicating the cause, duration, and location of 135 electric outages in the plant`s distribution system have allowed a reliability assessment to be performed. The assessment clearly shows how differences in voltage construction class, length, age, and maximum elevation above a reference elevation influence the reliability of overhead power distribution lines. Comparisons are also made between the ORNL historical data and predicted failure rates from ANSI and IEEE industry surveys.

  15. Broadband interferometer observations of a triggered lightning

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The development of positive leader of an artificially triggered lightning has been analyzed based on the data of electric field change, location of radiation source and frequency spectrum obtained by using the broadband interferometer system. The results indicate that radiation from positive leader could be detected within close distance in spite of the relatively weak radiation, while the radiation from negative breakdown processes was relatively stronger.Positive leader developed with few branches, and the initial progression velocity was of the order of 10s m/s. The distribution of power spectrum by 25 MHz high pass filter indicated that the radiation frequency from positive leader maximized at 25-30 MHz, while that from negative breakdown processes maximized at 60-70 MHz.

  16. Brazil Lightning Bolts Set Shocking World Record

    Institute of Scientific and Technical Information of China (English)

    卞小翩

    2002-01-01

    巴西是世界上最大的地处热带地区的国家,因此,它就成了世界“雷电之国”。让我们吃惊的是,10%of all lightning-rylated deaths in the world竟然发生在巴西!文章出现一个名词词组 power blackouts,而擅长使用词汇connotation的英语也常常“活用”此词。 He had had a blackout after the accident./事故发生后,他晕过去一阵子。

  17. Greased Lightning (GL-10) Flight Testing Campaign

    Science.gov (United States)

    Fredericks, William J.; McSwain, Robert G.; Beaton, Brian F.; Klassman, David W.; Theodore, Colin R.

    2017-01-01

    Greased Lightning (GL-10) is an aircraft configuration that combines the characteristics of a cruise efficient airplane with the ability to perform vertical takeoff and landing (VTOL). This aircraft has been designed, fabricated and flight tested at the small unmanned aerial system (UAS) scale. This technical memorandum will document the procedures and findings of the flight test experiments. The GL-10 design utilized two key technologies to enable this unique aircraft design; namely, distributed electric propulsion (DEP) and inexpensive closed loop controllers. These technologies enabled the flight of this inherently unstable aircraft. Overall it has been determined thru flight test that a design that leverages these new technologies can yield a useful VTOL cruise efficient aircraft.

  18. Sprites, Elves and Intense Lightning Discharges

    CERN Document Server

    Füllekrug, Martin; Rycroft, Michael J

    2006-01-01

    Particularly intense lightning discharges can produce transient luminous events above thunderclouds, termed sprites, elves and jets. These short lived optical emissions in the mesosphere can reach from the tops of thunderclouds up to the ionosphere; they provide direct evidence of coupling from the lower atmosphere to the upper atmosphere. Sprites are arguably the most dramatic recent discovery in solar-terrestrial physics. Shortly after the first ground based video recordings of sprites, observations on board the Space Shuttle detected sprites and elves occurring all around the world. These reports led to detailed sprite observations in North America, South America, Australia, Japan, and Europe. Subsequently, sprites were detected from other space platforms such as the International Space Station and the ROCSAT satellite. During the past 15 years, more than 200 contributions on sprites have been published in the scientific literature to document this rapidly evolving new research area.

  19. Modeling of overhead transmission lines for lightning overvoltage calculations

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Velasco, J.A.; Castro-Aranda, F.

    2010-10-15

    This article discussed the modelling of overhead transmission lines for lightning overvoltage calculations. Such a model must include those parts of the line that get involved when a lightning return stroke hits a wire or a tower and that have some influence on the voltage developed across insulator strings. Modelling guidelines differ depending on whether the goal is to estimate overvoltages or to determine arrester energy stresses. Modelling guidelines were summarized for each component, including shield wires and phase conductors; transmission line towers; insulators; phase voltages at the instant lightning hits the line; surge arresters; and the lightning stroke. The applied Monte Carlo procedure was summarized. For line span models, a constant-parameter model generally suffices when the goal is to calculate overvoltages across insulators or to obtain the flashover rate, but a frequency-dependent parameter model is necessary to estimate the energy discharged by arresters. The model selected for representing towers can have some influence on both flashover rates and arrester energy stresses. The representation of footing impedances is critical for calculating overvoltages and arrester energy stresses, but different modelling techniques produce significantly different results. The models are limited in that the corona effect is not included in the line models, the voltages induced by the electric and magnetic fields of lightning channels to shield wires and phase conductors are neglected, and the footing models are too simple, but they are nonetheless realistic approaches for simulating lightning effects. 2 tabs., 9 figs.

  20. Lightning and 85-GHz MCSs in the Global Tropics

    Science.gov (United States)

    Toracinta, E. Richard; Zipser, E. J.

    1999-01-01

    Numerous observations of tropical convection show that tropical continental mesoscale convective systems (MCSs) are much more prolific lightning producers than their oceanic counterparts. Satellite-based climatologies using 85-GHz passive microwave ice-scattering signatures from the Special Sensor Microwave/Imager (SSM/I) indicate that MCSs of various size and intensity are found throughout the global tropics. In contrast, global lightning distributions show a strong land bias with an order of magnitude difference between land and ocean lightning. This is somewhat puzzling, since 85-GHz ice-scattering and the charge separation processes that lead to lightning are both thought to depend upon the existence of large graupel particles. The fact that low 85-GHz brightness temperatures are observed in tropical oceanic MCSs containing virtually no lightning leads to the postulate that tropical oceanic and tropical continental MCSs have fundamentally different hydrometeor profiles through the mixed phase region of the cloud (0 C mind, this research undertakes a systematic comparison of 85-GHz-defined MCSs and lightning over the global tropics for a full year, as an initial step toward quantifying differences between land and ocean convective systems.

  1. The spectra and temperature of cloud lightning discharge channel

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Spectra of seven cloud lightning discharges are reported for the first time after captured with a Slit-less Spectrograph on Chinese Tibet Plateau. The structural characters are analyzed and compared with the spectra of cloud-to-ground lightning, and the results indicate that the spectra of cloud lightning show two different kinds of structure characteristics. One has the similar structure as those of cloud-to-ground lightning discharge, and the other is absolutely different. Meanwhile, more lines of OII with high excited energy are recorded in the spectra of cloud lightning discharge in comparison with that of cloud-to-ground lighting happening in the same region. Temperatures at different positions are calculated and temperature characteristics of these two sorts are analyzed, based to the wavelength, relative intensities and other transition parameters. We suggest that the physical process in the cloud discharge channels changes with much more rapid velocity and wider range compared to cloud-to-ground lightning. The differences between the two types of cloud discharge also reflect some discrepancies between the discharge characteristics.

  2. [Determination of Rh in removal solution of the catalyst from HNBR by FAAS].

    Science.gov (United States)

    Yao, Ming; Zhao, Wei-dong; Wang, Shu-jun; Xu, Rui-qing

    2003-04-01

    The content of Rhodium in extraction solution of the catalyst from HNBR was determined by FAAS. The results showed that this method was simple, rapid, accurate and convenient. Furthermore, this method was used as a means to investigate the optimum process conditions for removing catalyst from HNBR by ligation-extraction technology. When sulfocarbmide was used as a ligation agent and 88% formic acid as an extraction agent, the removal rate of Rh was greater than 98% under the condition of 100 degrees C and two hours of reaction time.

  3. RSRM top hat cover simulator lightning test, volume 2. Appendix A: Resistance measurements. Appendix B: Lightning test data plots

    Science.gov (United States)

    1990-01-01

    Resistance measurements are given in graphical for when a simulated lightning discharge strikes on an exposed top hat cover simulator. The test sequence was to measure the electric and magnetic fields induced inside a redesigned solid rocket motor case.

  4. Terrestrial gamma-ray flash production by lightning

    Science.gov (United States)

    Carlson, Brant E.

    Terrestrial gamma-ray flashes (TGFs) are brief flashes of gamma-rays originating in the Earth's atmosphere and observed by satellites. First observed in 1994 by the Burst And Transient Source Experiment on board the Compton Gamma-Ray Observatory, TGFs consist of one or more ˜1 ms pulses of gamma-rays with a total fluence of ˜1/cm2, typically observed when the satellite is near active thunderstorms. TGFs have subsequently been observed by other satellites to have a very hard spectrum (harder than dN/d E ∝ 1/ E ) that extends from below 25 keV to above 20 MeV. When good lightning data exists, TGFs are closely associated with measurable lightning discharge. Such discharges are typically observed to occur within 300 km of the sub-satellite point and within several milliseconds of the TGF observation. The production of these intense energetic bursts of photons is the puzzle addressed herein. The presence of high-energy photons implies a source of bremsstrahlung, while bremsstrahlung implies a source of energetic electrons. As TGFs are associated with lightning, fields produced by lightning are naturally suggested to accelerate these electrons. Initial ideas about TGF production involved electric fields high above thunderstorms as suggested by upper atmospheric lightning research and the extreme energies required for lower-altitude sources. These fields, produced either quasi-statically by charges in the cloud and ionosphere or dynamically by radiation from lightning strokes, can indeed drive TGF production, but the requirements on the source lightning are too extreme and therefore not common enough to account for all existing observations. In this work, studies of satellite data, the physics of energetic electron and photon production, and consideration of lightning physics motivate a new mechanism for TGF production by lightning current pulses. This mechanism is then developed and used to make testable predictions. TGF data from satellite observations are compared

  5. A History of the Lightning Launch Commit Criteria and the Lightning Advisory Panel for America's Space Program

    Science.gov (United States)

    Merceret, Francis J. (Editor); Willett, John C.; Christian, Hugh J.; Dye, James E.; Krider, E. Phillip; Madura, John T.; OBrien, T. Paul; Rust, W. David; Walterscheid, Richard L.

    2010-01-01

    The history of the Lightning Launch Commit Criteria (LLCC) used at all spaceports under the jurisdiction of the United States is provided. The formation and history of the Lightning Advisory Panel (LAP) that now advises NASA, the Air Force and the Federal Aviation Administration on LLCC development and improvement is emphasized. The period covered extends from the early days of space flight through 2010. Extensive appendices provide significant detail about important aspects that are only summarized in the main text.

  6. Evaluation of 1-phase, 3-phase and Lightning Faults on Wind Farms using EMTP-RV

    Directory of Open Access Journals (Sweden)

    Saber Arabi Nowdeh

    2014-12-01

    Full Text Available Since the development of wind power plants installation is growing, problems which are related to network connecting, stability and voltage effects become more important. On the other hand, wind farms are often open to lightning because of their long height and specific appearance. In this paper, modeling and simulation of 1-phase, 3-phase and lightning faults in a wind farm consisting of 40 wind turbines and faults impact on wind farm and the network is investigated in EMTP-RV environment. In this field, it’s necessary to develop a precise modeling out of wind power plant in order to evaluate the effects of these power plants on dynamical behavior of the power system. These models can be used in designing new protection systems, new protection algorithms, and new strategies for power plants exploitation improvement. Each wind unit in the farm is connected to the whole units that are connected to the network using a doubly fed induction generator (DFIG.

  7. Statistical Analysis for Probable Varying Potential Lightnings Strokes to Extended Objects%Statistical Analysis for Probable Varying Potential Lightnings Strokes to Extended Objects

    Institute of Scientific and Technical Information of China (English)

    M. Rezinkina; O. Rezinkin; C. Bean; S.R. Chalise; J. Grastya

    2011-01-01

    In the paper, the statistical modeling method of the lightning attachment process to extended objects has been proposed. The modeling takes into account the probabilities of lightning occurrence with current of different am- plitudes, and nonlinear variation of spark resistance at leader channel growth. The method also takes into considera- tion the dependency of velocity and acceleration of a lightning leader on its potential. The propagation of lightning channel towards the earth is tortuous and random in orientation and does not depend upon ground objects until it en- ters into "last stroke zone". It assumes that the lightning leader channel orientation begins when its streamer zone touches the earth, a grounded object, a grounded lightning rod or a streamer zone of the ascending leader. The proba- ble frequency of lightning strikes to an investigated object can be obtained by the summation of the total probable number of strikes of all possible potentials at each node of the object, appearing with the assigned probability, as well as the points of origin of the heads of lightning leaders from all nodes on the plain (over the object) at corresponding heights. The proposed method is implemented to ealculate the lightning stroke probability to a high voltage substation. Due to lightning attraction from the territory greater than that of the investigated object, the total number of annual probable lightning strokes to the object is increased by 1.28 times in comparison with the case of the same flat territory.

  8. Relationship between lightning activity and tropospheric nitrogen dioxide and the estimation of lightning-produced nitrogen oxides over China

    Science.gov (United States)

    Guo, Fengxia; Ju, Xiaoyu; Bao, Min; Lu, Ganyi; Liu, Zupei; Li, Yawen; Mu, Yijun

    2017-02-01

    To better understand the relationship between lightning activity and nitrogen oxides (NO X ) in the troposphere and to estimate lightning-produced NO X (LNO X ) production in China more precisely, spatial and temporal distributions of vertical column densities of tropospheric nitrogen dioxide (NO2 VCDs) and lightning activity were analyzed using satellite measurements. The results showed that the spatial distribution of lightning activity is greater in the east than in the west of China, as with NO2 VCDs. However, the seasonal and annual variation between lightning and NO2 density show different trends in the east and west. The central Tibetan Plateau is sparsely populated without modern industry, and NO2 VCDs across the plateau are barely affected by anthropogenic sources. The plateau is an ideal area to study LNO X . By analyzing 15 years of satellite data from that region, it was found that lightning density is in strong agreement with annual, spatial and seasonal variations of NO2 VCDs, with a correlation coefficient of 0.79 from the linear fit. Combining Beirle's method and the linear fit equation, LNO X production in the Chinese interior was determined to be 0.07 (0.02-0.27) TgN yr-1 for 1997-2012, within the range of 0.016-0.384 TgN yr-1 from previous estimates.

  9. 1000 Year-old Trees Protected

    Institute of Scientific and Technical Information of China (English)

    柏凤文

    2000-01-01

    Wuhan (Xinhua) : Ninety-seven ginkgo(银杏) trees in the city of Suizhou, each more than 1 000 years old, have been equipped with lightning rods(避雷针) and placed under special protection by local villagers in Central China's Hubei Province.

  10. The FAA's postmortem forensic toxicology self-evaluated proficiency test program: the second seven years.

    Science.gov (United States)

    Chaturvedi, Arvind K; Craft, Kristi J; Cardona, Patrick S; Rogers, Paul B; Canfield, Dennis V

    2009-05-01

    During toxicological evaluations of samples from fatally injured pilots involved in civil aviation accidents, a high degree of quality control/quality assurance (QC/QA) is maintained. Under this philosophy, the Federal Aviation Administration (FAA) started a forensic toxicology proficiency-testing (PT) program in July 1991. In continuation of the first seven years of the PT findings reported earlier, PT findings of the next seven years are summarized herein. Twenty-eight survey samples (12 urine, 9 blood, and 7 tissue homogenate) with/without alcohols/volatiles, drugs, and/or putrefactive amine(s) were submitted to an average of 31 laboratories, of which an average of 25 participants returned their results. Analytes in survey samples were correctly identified and quantitated by a large number of participants, but some false positives of concern were reported. It is anticipated that the FAA's PT program will continue to serve the forensic toxicology community through this important part of the QC/QA for laboratory accreditations.

  11. TRAMWAY SYSTEM VULNERABILITIES CAUSED BY STORM. CASE STUDY: LIGHTNING IN ORADEA, 10-TH JUNE 2013

    Directory of Open Access Journals (Sweden)

    CSUZI I.

    2016-09-01

    Full Text Available Short history, theoretical presentation, risk analysis of damage probability of extreme weather effects, lightning and storm, technical and economic aspects, recommendation for public transport operators. Case study: example of a lightning damage effects in Oradea.

  12. Lightning Detection Efficiency Analysis Process: Modeling Based on Empirical Data

    Science.gov (United States)

    Rompala, John T.

    2005-01-01

    A ground based lightning detection system employs a grid of sensors, which record and evaluate the electromagnetic signal produced by a lightning strike. Several detectors gather information on that signal s strength, time of arrival, and behavior over time. By coordinating the information from several detectors, an event solution can be generated. That solution includes the signal s point of origin, strength and polarity. Determination of the location of the lightning strike uses algorithms based on long used techniques of triangulation. Determination of the event s original signal strength relies on the behavior of the generated magnetic field over distance and time. In general the signal from the event undergoes geometric dispersion and environmental attenuation as it progresses. Our knowledge of that radial behavior together with the strength of the signal received by detecting sites permits an extrapolation and evaluation of the original strength of the lightning strike. It also limits the detection efficiency (DE) of the network. For expansive grids and with a sparse density of detectors, the DE varies widely over the area served. This limits the utility of the network in gathering information on regional lightning strike density and applying it to meteorological studies. A network of this type is a grid of four detectors in the Rondonian region of Brazil. The service area extends over a million square kilometers. Much of that area is covered by rain forests. Thus knowledge of lightning strike characteristics over the expanse is of particular value. I have been developing a process that determines the DE over the region [3]. In turn, this provides a way to produce lightning strike density maps, corrected for DE, over the entire region of interest. This report offers a survey of that development to date and a record of present activity.

  13. Lightning climatology in the Congo Basin: methodology and first results

    Science.gov (United States)

    Kigotsi, Jean; Soula, Serge; Georgis, Jean-François; Barthe, Christelle

    2016-04-01

    The global climatology of lightning issued from space observations (OTD and LIS) clearly showed the maximum of the thunderstorm activity is located in a large area of the Congo Basin, especially in the Democratic Republic of Congo (DRC). The first goal of the present study is to compare observations from the World Wide Lightning Location Network (WWLLN) from the Lightning Imaging Sensor (LIS) over a 9-year period (2005-2013) in this 2750 km × 2750 km area. The second goal is to analyse the lightning activity in terms of time and space variability. The detection efficiency (DE) of the WWLLN relative to LIS has increased between 2005 and 2013, typically from about 1.70 % to 5.90 %, in agreement with previous results for other regions of the world. The mean monthly flash rate describes an annual cycle with a maximum between November and March and a minimum between June and August, associated with the ICTZ migration but not exactly symmetrical on both sides of the equator. The diurnal evolution of the flash rate has a maximum between 1400 and 1700 UTC, depending on the reference year, in agreement with previous works in other regions of the world. The annual flash density shows a sharp maximum localized in eastern DRC regardless of the reference year and the period of the year. This annual maximum systematically located west of Kivu Lake corresponds to that previously identified by many authors as the worldwide maximum which Christian et al. (2013) falsely attributed to Rwanda. Another more extended region within the Congo Basin exhibits moderately large values, especially during the beginning of the period analyzed. A comparison of both patterns of lightning density from the WWLLN and from LIS allows to validate the representativeness of this world network and to restitute the total lightning activity in terms of lightning density and rate.

  14. Nearshore regional behavior of lightning interaction with wind turbines

    Directory of Open Access Journals (Sweden)

    Gilbert A. Malinga

    2016-01-01

    Full Text Available The severity of lightning strikes on offshore wind turbines built along coastal and nearshore regions can pose safety concerns that are often overlooked. In this research study the behavior of electrical discharges for wind turbines that might be located in the nearshore regions along the East Coast of China and Sea of Japan were characterized using a physics-based model that accounted for a total of eleven different geometrical and lightning parameters. Utilizing the electrical potential field predicted using this model it was then possible to estimate the frequency of lightning strikes and the distribution of electrical loads utilizing established semi-empirical relationships and available data. The total number of annual lightning strikes on an offshore wind turbine was found to vary with hub elevation, extent of cloud cover, season and geographical location. The annual lightning strike rate on a wind turbine along the nearshore region on the Sea of Japan during the winter season was shown to be moderately larger compared to the lightning strike frequency on a turbine structure on the East Coast of China. Short duration electrical discharges, represented using marginal probability functions, were found to vary with season and geographical location, exhibiting trends consistent with the distribution of the electrical peak current. It was demonstrated that electrical discharges of moderately long duration typically occur in the winter months on the East Coast of China and the summer season along the Sea of Japan. In contrast, severe electrical discharges are typical of summer thunderstorms on the East Coast of China and winter frontal storm systems along the West Coast of Japan. The electrical charge and specific energy dissipated during lightning discharges on an offshore wind turbine was found to vary stochastically, with severe electrical discharges corresponding to large electrical currents of long duration.

  15. Analysis of Channel Luminosity Characteristics in Rocket-Triggered Lightning

    Institute of Scientific and Technical Information of China (English)

    LU Weitao; ZHANG Yijun; ZHOU Xiuji; MENG Qing; ZHENG Dong; MA Ming; WANG Fei; CHEN Shaodong; QIE Xiushu

    2008-01-01

    A comparison is made of the high-speed(2000 fps)photographic records in rocket-triggered negative lightning between two techniques.The analysis shows that:the initial speed of upward positive leader (UPL)in altitude-triggered negative lightning(ATNL)is about one order of magnitude less than that in classically triggered negative lightning(CTNL),while the triggering height of ATNL is higher than that of CTNL;the afterglow time of metal-vaporized part of the lightning channel Call endure for about 160-170 ms,thus the luminosity of the air-ionized part can reflect the characteristics of the current in the lightning channel better than that of the metal-vaporized part.According to the different characteristics of the luminosity change of the lightning channel,together with the observation of the electric field changes,three kinds of processes after return-stroke(RS)can be distinguished:the continuous decaying type without M component,the isolated type and the continuing type with M component,corresponding to different wave shapes of the continuous current.The geometric mean of the interval of RS with M component is 77 ms,longer than that(37 ms)of RS without M component.And the initial continuous current(ICC)with M component also has a longer duration compared to the ICC without M component.The distinction in the relative luminosity between the lightning channel before RS and that before M component is obvious:the former is very weak or even cannot be observed,while the latter is still considerably luminous.

  16. Lightning safety awareness of visitors in three California national parks.

    Science.gov (United States)

    Weichenthal, Lori; Allen, Jacoby; Davis, Kyle P; Campagne, Danielle; Snowden, Brandy; Hughes, Susan

    2011-09-01

    To assess the level of lightning safety awareness among visitors at 3 national parks in the Sierra Nevada Mountains of California. A 12-question, short answer convenience sample survey was administered to participants 18 years of age and over concerning popular trails and points of interest with known lightning activity. There were 6 identifying questions and 5 knowledge-based questions pertaining to lightning that were scored on a binary value of 0 or 1 for a total of 10 points for the survey instrument. Volunteers in Fresno, California, were used as a control group. Participants were categorized as Sequoia and Kings Canyon National Park (SEKI), frontcountry (FC), or backcountry (BC); Yosemite National Park (YNP) FC or BC; and Fresno. Analysis of variance (ANOVA) was used to test for differences between groups. 467 surveys were included for analysis: 77 in Fresno, 192 in SEKI, and 198 in YNP. National park participants demonstrated greater familiarity with lightning safety than individuals from the metropolitan community (YNP 5.84 and SEKI 5.65 vs Fresno 5.14, P = .0032). There were also differences noted between the BC and FC subgroups (YNP FC 6.07 vs YNP BC 5.62, P = .02; YNP FC 6.07 vs SEKI FC 5.58, P = .02). Overall results showed that participants had certain basic lightning knowledge but lacked familiarity with other key lightning safety recommendations. While there are statistically significant differences in lightning safety awareness between national parks and metropolitan participants, the clinical impact of these findings are debatable. This study provides a starting point for providing educational outreach to visitors in these national parks. Copyright © 2011 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

  17. Learning from concurrent Lightning Imaging Sensor and Lightning Mapping Array observations in preparation for the MTG-LI mission

    Science.gov (United States)

    Defer, Eric; Bovalo, Christophe; Coquillat, Sylvain; Pinty, Jean-Pierre; Farges, Thomas; Krehbiel, Paul; Rison, William

    2016-04-01

    The upcoming decade will see the deployment and the operation of French, European and American space-based missions dedicated to the detection and the characterization of the lightning activity on Earth. For instance the Tool for the Analysis of Radiation from lightNIng and Sprites (TARANIS) mission, with an expected launch in 2018, is a CNES mission dedicated to the study of impulsive energy transfers between the atmosphere of the Earth and the space environment. It will carry a package of Micro Cameras and Photometers (MCP) to detect and locate lightning flashes and triggered Transient Luminous Events (TLEs). At the European level, the Meteosat Third Generation Imager (MTG-I) satellites will carry in 2019 the Lightning Imager (LI) aimed at detecting and locating the lightning activity over almost the full disk of Earth as usually observed with Meteosat geostationary infrared/visible imagers. The American community plans to operate a similar instrument on the GOES-R mission for an effective operation in early 2016. In addition NASA will install in 2016 on the International Space Station the spare version of the Lightning Imaging Sensor (LIS) that has proved its capability to optically detect the tropical lightning activity from the Tropical Rainfall Measuring Mission (TRMM) spacecraft. We will present concurrent observations recorded by the optical space-borne Lightning Imaging Sensor (LIS) and the ground-based Very High Frequency (VHF) Lightning Mapping Array (LMA) for different types of lightning flashes. The properties of the cloud environment will also be considered in the analysis thanks to coincident observations of the different TRMM cloud sensors. The characteristics of the optical signal will be discussed according to the nature of the parent flash components and the cloud properties. This study should provide some insights not only on the expected optical signal that will be recorded by LI, but also on the definition of the validation strategy of LI, and

  18. Lightning Observations from the International Space Station (ISS) for Science Research and Operational Applications

    Science.gov (United States)

    Blakeslee, R. J.; Christian, H. J.; Mach, D. M.; Buechler, D. E.; Koshak, W. J.; Walker, T. D.; Bateman, M.; Stewart, M. F.; O'Brien, S.; Wilson, T.; hide

    2015-01-01

    There exist several core science applications of LIS lightning observations, that range from weather and climate to atmospheric chemistry and lightning physics due to strong quantitative connections that can be made between lightning and other geophysical processes of interest. The space-base vantage point, such as provided by ISS LIS, still remains an ideal location to obtain total lightning observations on a global basis.

  19. Technique for the comparison of light spectra from natural and laboratory generated lightning current arcs

    Science.gov (United States)

    Mitchard, D.; Clark, D.; Carr, D.; Haddad, A.

    2016-08-01

    A technique was developed for the comparison of observed emission spectra from lightning current arcs generated through self-breakdown in air and the use of two types of initiation wire, aluminum bronze and nichrome, against previously published spectra of natural lightning events. A spectrograph system was used in which the wavelength of light emitted by the lightning arc was analyzed to derive elemental interactions. A lightning impulse of up to 100 kA was applied to a two hemispherical tungsten electrode configuration which allowed the effect of the lightning current and lightning arc length to be investigated. A natural lightning reference spectrum was reconstructed from literature, and generated lightning spectra were obtained from self-breakdown across a 14.0 mm air gap and triggered along initiation wires of length up to 72.4 mm. A comparison of the spectra showed that the generated lightning arc induced via self-breakdown produced a very similar spectrum to that of natural lightning, with the addition of only a few lines from the tungsten electrodes. A comparison of the results from the aluminum bronze initiation wire showed several more lines, whereas results from the nichrome initiation wire differed greatly across large parts of the spectrum. This work highlights the potential use for spectrographic techniques in the study of lightning interactions with surrounding media and materials, and in natural phenomena such as recently observed ball lightning.

  20. Technique for the comparison of light spectra from natural and laboratory generated lightning current arcs

    Energy Technology Data Exchange (ETDEWEB)

    Mitchard, D., E-mail: mitcharddr@cardiff.ac.uk; Clark, D.; Carr, D.; Haddad, A. [Morgan-Botti Lightning Laboratory, Advanced High Voltage Research Centre, School of Engineering, Cardiff University, CF24 3AA Wales (United Kingdom)

    2016-08-29

    A technique was developed for the comparison of observed emission spectra from lightning current arcs generated through self-breakdown in air and the use of two types of initiation wire, aluminum bronze and nichrome, against previously published spectra of natural lightning events. A spectrograph system was used in which the wavelength of light emitted by the lightning arc was analyzed to derive elemental interactions. A lightning impulse of up to 100 kA was applied to a two hemispherical tungsten electrode configuration which allowed the effect of the lightning current and lightning arc length to be investigated. A natural lightning reference spectrum was reconstructed from literature, and generated lightning spectra were obtained from self-breakdown across a 14.0 mm air gap and triggered along initiation wires of length up to 72.4 mm. A comparison of the spectra showed that the generated lightning arc induced via self-breakdown produced a very similar spectrum to that of natural lightning, with the addition of only a few lines from the tungsten electrodes. A comparison of the results from the aluminum bronze initiation wire showed several more lines, whereas results from the nichrome initiation wire differed greatly across large parts of the spectrum. This work highlights the potential use for spectrographic techniques in the study of lightning interactions with surrounding media and materials, and in natural phenomena such as recently observed ball lightning.

  1. Laboratory Calibration of the Optical Transient Detector (OTD) and the Lightning Imaging Sensor (LIS)

    Science.gov (United States)

    Koshak, William J.; Stewart, Mike F.; Christian, Hugh J.; Bergstrom, James W.; Hall, John M.; Solakiewicz, Richard J.

    1994-01-01

    We present in detail the laboratory apparatus and techniques that were used to complete a full radiometric calibration of two space-based lightning detectors developed at NASA Marshall Space Flight Center (MSFC). A discussion of the methods applied to geolocate lightning and to estimate lightning detection efficiency are provided.

  2. Spatial and temporal characteristics of VHF radiation source produced by lightning in supercell thunderstorms

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yijun; MENG Qing; P. R. Krehbiel; LIU Xinsheng; ZHOU Xiuji

    2004-01-01

    The three-dimensional temporal and spatial characteristics of VHF radiation events produced by lightning discharges in three supercell thunderstorms have been analyzed based on the data measured by the lightning mapping array system with high time and space resolution. The results indicate that lightning hole (lighting free region) with about 5-6 km in diameter or lighting ring (annular lighting free region) is associated with the strong updraft in thunderstorm. The lasting time of lightning holes is either short or long, being about 20 min in a tornado-producing thunderstorm. The lightning holes appear before the occurrence of tornado. The lightning hole is the most obvious during the occurrence of tornado and some self-existent lighting radiation events appear at a height of 15-16 km. The lightning channels of inter-cloud (IC) lightning discharge exhibit clockwise rotary structures and do not have clear bilevel structures in the vicinity of the tornado. The lightning holes are corresponding to the strong updraft region. The temporal and spatial distribution of lightning radiation events reveals the structure of strong updraft in supercell thunderstorms.Positive cloud-to-ground (CG) lightning discharges dominate in these thunderstorms and the peak of positive CG lightning flash rate appears, with the maximum of 6 per minute, after or before the occurrence of tornado.

  3. Global lightning and severe storm monitoring from GPS orbit

    Energy Technology Data Exchange (ETDEWEB)

    Suszcynsky, D. M. (David M.); Jacobson, A. R.; Linford, J (Justin); Pongratz, M. B. (Morris B.); Light, T. (Tracy E.); Shao, X. (Xuan-Min)

    2004-01-01

    Over the last few decades, there has been a growing interest to develop and deploy an automated and continuously operating satellite-based global lightning mapper [e.g. Christian et al., 1989; Weber et al., 1998; Suszcynsky et al., 2000]. Lightning is a direct consequence of the electrification and breakdown processes that take place during the convective stages of thunderstorm development. Satellite-based lightning mappers are designed to exploit this relationship by using lightning detection as a proxy for remotely identifying, locating and characterizing strong convective activity on a global basis. Global lightning and convection mapping promises to provide users with (1) an enhanced global severe weather monitoring and early warning capability [e.g. Weber et al., 1998] (2) improved ability to optimize aviation flight paths around convective cells, particularly over oceanic and remote regions that are not sufficiently serviced by existing weather radar [e.g. Weber et al., 1998], and (3) access to regional and global proxy data sets that can be used for scientific studies and as input into meteorological forecast and global climatology models. The physical foundation for satellite-based remote sensing of convection by way of lightning detection is provided by the basic interplay between the electrical and convective states of a thundercloud. It is widely believed that convection is a driving mechanism behind the hydrometeor charging and transport that produces charge separation and lightning discharges within thunderclouds [e.g. see chapter 3 in MacGorman and Rust, 1998]. Although cloud electrification and discharge processes are a complex function of the convective dynamics and microphysics of the cloud, the fundamental relationship between convection and electrification is easy to observe. For example, studies have shown that the strength of the convective process within a thundercell can be loosely parameterized (with large variance) by the intensity of the

  4. Direct satellite observation of lightning-produced NOx

    Directory of Open Access Journals (Sweden)

    T. Wagner

    2010-08-01

    Full Text Available Lightning is an important source of NOx in the free troposphere, especially in the tropics, with high impact on ozone production. However, estimates of lightning NOx (LNOx production efficiency (LNOx per flash are still quite uncertain. In this study we present a systematic analysis of NO2 column densities from SCIAMACHY measurements over active thunderstorms, as detected by the World-Wide Lightning Location Network (WWLLN, where the WWLLN detection efficiency was estimated using the flash climatology of the satellite lightning sensors LIS/OTD. Only events with high lightning activity are considered, where corrected WWLLN flash rate densities inside the satellite pixel within the last hour are above 1 /km2/h. For typical SCIAMACHY ground pixels of 30×60 km2, this threshold corresponds to 1800 flashes over the last hour, which, for literature estimates of lightning NOx production, should result in clearly enhanced NO2 column densities. From 2004–2008, we find 287 coincidences of SCIAMACHY measurements and high WWLLN flash rate densities. For some of these events, a clear enhancement of column densities of NO2 could be observed, indeed. But overall, the measured column densities are below the expected values by more than one order of magnitude, and in most of the cases, no enhanced NO2 could be found at all. Our results are in contradiction to the currently accepted range of LNOx production per flash of 15 (2–40×1025 molec/flash. This probably partly results from the specific conditions for the events under investigation, i.e. events of high lightning activity in the morning (local time and mostly (for 162 out of 287 events over ocean. Within the detected coincidences, the highest NO2 column densities were observed around the US Eastcoast. This might be partly due to interference with ground sources of NOx being uplifted by the convective systems. However, it could also indicate that flashes in this region are particularly productive. We

  5. 76 FR 8917 - Special Conditions: Gulfstream Model GVI Airplane; Automatic Speed Protection for Design Dive Speed

    Science.gov (United States)

    2011-02-16

    ...; Automatic Speed Protection for Design Dive Speed AGENCY: Federal Aviation Administration (FAA), DOT. ACTION... design features include a high speed protection system. These proposed special conditions contain the... Design Features The GVI is equipped with a high speed protection system that limits nose down...

  6. Time domain simulations of preliminary breakdown pulses in natural lightning

    Science.gov (United States)

    Carlson, B E; Liang, C; Bitzer, P; Christian, H

    2015-01-01

    Lightning discharge is a complicated process with relevant physical scales spanning many orders of magnitude. In an effort to understand the electrodynamics of lightning and connect physical properties of the channel to observed behavior, we construct a simulation of charge and current flow on a narrow conducting channel embedded in three-dimensional space with the time domain electric field integral equation, the method of moments, and the thin-wire approximation. The method includes approximate treatment of resistance evolution due to lightning channel heating and the corona sheath of charge surrounding the lightning channel. Focusing our attention on preliminary breakdown in natural lightning by simulating stepwise channel extension with a simplified geometry, our simulation reproduces the broad features observed in data collected with the Huntsville Alabama Marx Meter Array. Some deviations in pulse shape details are evident, suggesting future work focusing on the detailed properties of the stepping mechanism. Key Points Preliminary breakdown pulses can be reproduced by simulated channel extension Channel heating and corona sheath formation are crucial to proper pulse shape Extension processes and channel orientation significantly affect observations PMID:26664815

  7. Response of global lightning activity to air temperature variation

    Institute of Scientific and Technical Information of China (English)

    MA Ming; TAO Shanchang; ZHU Baoyou; L(U) Weitao; TAN Yongbo

    2005-01-01

    It is an issue of great attention but yet not very clear whether lightning activities increase or decrease on a warmer world. Reeve et al. presented that lightning activities in global land and the Northern Hemisphere land have positive response to the increase of wet bulb temperature at 1000hPa. Is this positive response restricted only to wet bulb temperature or in land? What is the response of global lightning activities (in both land and ocean) to the global surface air temperature variation like? This paper, based on the 5-year or 8-year OTD/LIS satellite-based lightning detecting data and the NCEP reanalysis data, makes a reanalysis of the response of the global and regional lightning activities to temperature variations. The results show that on the interannual time scale the global total flash rate has positive response to the variation in global surface air temperature, with the sensitivity of 17±7% K-1. Also, the seasonal mean flash rate of continents all over the world and that of continents in the Northern Hemisphere have sensitive positive response to increase of global surface air temperature and wet bulb temperature, with the sensitivity of about 13±5% K-1, a bit lower than estimation of 40% K-1 in Reeve et al. However, the Southern Hemisphere and other areas like the tropics show no significant correlation.

  8. Lightning-based propagation of convective rain fields

    Directory of Open Access Journals (Sweden)

    S. Dietrich

    2011-05-01

    Full Text Available This paper describes a new multi-sensor approach for continuously monitoring convective rain cells. It exploits lightning data from surface networks to propagate rain fields estimated from multi-frequency brightness temperature measurements taken by the AMSU/MHS microwave radiometers onboard NOAA/EUMETSAT low Earth orbiting operational satellites. Specifically, the method allows inferring the development (movement, morphology and intensity of convective rain cells from the spatial and temporal distribution of lightning strokes following any observation by a satellite-borne microwave radiometer. Obviously, this is particularly attractive for real-time operational purposes, due to the sporadic nature of the low Earth orbiting satellite measurements and the continuous availability of ground-based lightning measurements – as is the case in most of the Mediterranean region. A preliminary assessment of the lightning-based rainfall propagation algorithm has been successfully made by using two pairs of consecutive AMSU observations, in conjunction with lightning measurements from the ZEUS network, for two convective events. Specifically, we show that the evolving rain fields, which are estimated by applying the algorithm to the satellite-based rainfall estimates for the first AMSU overpass, show an overall agreement with the satellite-based rainfall estimates for the second AMSU overpass.

  9. Time domain simulations of preliminary breakdown pulses in natural lightning.

    Science.gov (United States)

    Carlson, B E; Liang, C; Bitzer, P; Christian, H

    2015-06-16

    Lightning discharge is a complicated process with relevant physical scales spanning many orders of magnitude. In an effort to understand the electrodynamics of lightning and connect physical properties of the channel to observed behavior, we construct a simulation of charge and current flow on a narrow conducting channel embedded in three-dimensional space with the time domain electric field integral equation, the method of moments, and the thin-wire approximation. The method includes approximate treatment of resistance evolution due to lightning channel heating and the corona sheath of charge surrounding the lightning channel. Focusing our attention on preliminary breakdown in natural lightning by simulating stepwise channel extension with a simplified geometry, our simulation reproduces the broad features observed in data collected with the Huntsville Alabama Marx Meter Array. Some deviations in pulse shape details are evident, suggesting future work focusing on the detailed properties of the stepping mechanism. Preliminary breakdown pulses can be reproduced by simulated channel extension Channel heating and corona sheath formation are crucial to proper pulse shape Extension processes and channel orientation significantly affect observations.

  10. Lightning-induced overvoltages in medium voltage distribution systems and customer experienced voltage spikes

    Energy Technology Data Exchange (ETDEWEB)

    Sabiha, N. A.

    2010-07-01

    In Finland, distribution transformers are frequently subjected to lightning strokes for which they are continuously protected by spark-gaps. So, the breakdown probability of medium voltage (MV) spark-gaps is modeled using the Gaussian distribution function under an impulse voltage test in accordance with the IEC 60060-1 standard. The model is presented in the form of the well-known Gaussian tail probability. Accordingly, a modified probabilistic model is proposed to study the effect of impulse voltage superimposed on the ac voltage on the breakdown probability of MV spark-gaps. The modified model is verified using experimental data, where the experimental setup is arranged to generate a range of impulse voltages superimposed on the ac voltages. The experimental verification shows evidence of the efficacy of the proposed probabilistic model. Furthermore, the proposed model is used to evaluate single-phase, two-phase and three-phase spark-gap breakdown probabilities in the case of lightning induced overvoltages. These breakdown probabilities are used along with the simplified Rusck expression to evaluate the performance of MV overhead lines above a perfectly conducting ground under lightning-induced overvoltages using a statistical approach. In order to study the overvoltages propagating through the transformer to its low voltage side, the high frequency model of the transformer is investigated. First, the investigation is carried out using model introduced by Piantini at no-load condition. This model is modified to take more than one resonance frequency into consideration. Therefore, the frequency response of the simulated transient voltage is improved. A verification of the modified model is carried out through the comparison between the experimental and simulation results, in which the time domain simulation is carried out using ATP/EMTP while MATLAB is used to identify the model parameters. As this model is found suitable only for unloaded transformer, an

  11. Broadband electromagnetic sensors for aircraft lightning research. [electromagnetic effects of lightning on aircraft digital equipment

    Science.gov (United States)

    Trost, T. F.; Zaepfel, K. P.

    1980-01-01

    A set of electromagnetic sensors, or electrically-small antennas, is described. The sensors are designed for installation on an F-106 research aircraft for the measurement of electric and magnetic fields and currents during a lightning strike. The electric and magnetic field sensors mount on the aircraft skin. The current sensor mounts between the nose boom and the fuselage. The sensors are all on the order of 10 cm in size and should produce up to about 100 V for the estimated lightning fields. The basic designs are the same as those developed for nuclear electromagnetic pulse studies. The most important electrical parameters of the sensors are the sensitivity, or equivalent area, and the bandwidth (or rise time). Calibration of sensors with simple geometries is reliably accomplished by a geometric analysis; all the sensors discussed possess geometries for which the sensitivities have been calculated. For the calibration of sensors with more complex geometries and for general testing of all sensors, two transmission lines were constructed to transmit known pulsed fields and currents over the sensors.

  12. Ice multiplication by mechanical breakup and lightning

    Science.gov (United States)

    Phillips, Vaughan; Yano, Jun-Ichi

    2016-04-01

    Laboratory studies have proven the existence of several pathways for fragmentation of ice. One of these is the rime-splintering of graupel or hail in the -3 to -8 degC region (the Hallett-Mossop process). In some clouds, however, the cloud-base is too cold for this process to be active. Instead, breakup can occur by fragmentation of ice mechanically in re-bounding collisions between crystals, snow, graupel or hail. A new theoretical formulation of this mechanical breakup process of multiplication is presented for these types of ice. A numerical scheme is derived by simulation of published laboratory experiments. The role of such breakup in clouds is quantified by 3D simulations with a cloud-resolving aerosol-cloud model with emulated bin microphysics, detailed treatment of ice morphology and 7 chemical species of aerosol. Graupel-graupel collisions are predicted to produce copious numbers of ice crystals in the cold-base convective cloud simulated over Kansas. Implications for lightning from such multiplication, also simulated numerically, are discussed.

  13. ADSORPTION BEHAVIOR OF Pb(II) ON POTASSIUM HEXATITANATE WHISKER BY FAAS

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Based on the advantage of high surface area and strong adsorption ability of potassium hexatitanate whisker, a method to determine trace Pb(II) content by combining solid phase extraction with Flame atomic absorption spectrometry (FAAS) was established. The adsorptive behavior of potassium hexatitanate whisker to Pb(II), primary influencing factors of adsorption and elution and effect of coexistence ions were investigated systemically. The optimal analytical conditions were discussed and examined. It was found that the adsorption rate of potassium hexatitanate whisker to Pb(II) was 100% at pH 4.0. Pb(II) could be eluted from potassium tetratitanate whisker with HCl (2mol/L) under boiling water for 30min. The detection limit was 5.75ng/mL, and relative standard deviation was 1.66% (n=9, CPb=2.0μg/mL).

  14. Precision Departure Release Capability (PDRC) Overview and Results: NASA to FAA Research Transition

    Science.gov (United States)

    Engelland, Shawn; Davis, Tom.

    2013-01-01

    NASA researchers developed the Precision Departure Release Capability (PDRC) concept to improve the tactical departure scheduling process. The PDRC system is comprised of: 1) a surface automation system that computes ready time predictions and departure runway assignments, 2) an en route scheduling automation tool that uses this information to estimate ascent trajectories to the merge point and computes release times and, 3) an interface that provides two-way communication between the two systems. To minimize technology transfer issues and facilitate its adoption by TMCs and Frontline Managers (FLM), NASA developed the PDRC prototype using the Surface Decision Support System (SDSS) for the Tower surface automation tool, a research version of the FAA TMA (RTMA) for en route automation tool and a digital interface between the two DSTs to facilitate coordination.

  15. ADSORPTION BEHAVIOR OF Pb(Ⅱ) ON POTASSIUM HEXATITANATE WHISKER BY FAAS

    Institute of Scientific and Technical Information of China (English)

    CHENG Yonghua; XU Wanzhen; YAN Yongsheng; JING Junjie

    2008-01-01

    Based on the advantage of high surface area and strong adsorption ability of potassium hexatitanate whisker, a method to determine trace Pb(Ⅱ) content by combining solid phase extraction with Flame atomic absorption spectrometry (FAAS) was established.The adsorptive behavior of potassium hexatitanate whisker to Pb(Ⅱ), primary influencing factors of adsorption and elation and effect of coexistence ions were investigated systemically.The optimal analytical conditions were discussed and examined.It was found that the adsorption rate of potassium hexatitanate whisker to Pb(Ⅱ) was 100% at pH 4.0.Pb(Ⅱ) could be elated from potassium tetratitanate whisker with HCI (2mol/L) under boiling water for 30min.The detection limit was 5.75ng/mL, and relative standard deviation was 1.66% (n=9, CPb=2.0μg/mL).

  16. NASA,FAA,ONERA Swept-Wing Icing and Aerodynamics: Summary of Research and Current Status

    Science.gov (United States)

    Broeren, Andy

    2015-01-01

    NASA, FAA, ONERA, and other partner organizations have embarked on a significant, collaborative research effort to address the technical challenges associated with icing on large scale, three-dimensional swept wings. These are extremely complex phenomena important to the design, certification and safe operation of small and large transport aircraft. There is increasing demand to balance trade-offs in aircraft efficiency, cost and noise that tend to compete directly with allowable performance degradations over an increasing range of icing conditions. Computational fluid dynamics codes have reached a level of maturity that they are being proposed by manufacturers for use in certification of aircraft for flight in icing. However, sufficient high-quality data to evaluate their performance on iced swept wings are not currently available in the public domain and significant knowledge gaps remain.

  17. FAA Air Traffic Control Operations Concepts. Volume 7. ATCT (Airport Traffic Control Towers) Tower Controllers

    Science.gov (United States)

    1989-04-21

    DEVIATION SI’UATION RESORVE DEVIA11ON SITUATION REU IRED ý1.2.4.3 f i f FOCMULATE ADVSORY/ SAFETY GEERATE CLEARANCE ALERT GWENTET T1.3.1.6 PISSUEIH...l BN AIRCRAFT VEHICLEJ L~ Z S CTP1T1.4.2.2 11 .2.4.1___ RECEIVE NOT IC OF S’ECIAL OBERVE A-IRCRAFT! VEHICLE Cct-7ION~c-/ EMERGIEFNY PERCEIVE. PRESE...1RESPF•WIUNGTO 1 RANSIENT M( Z •NIlC4,11(11 FAILURES T1.7.8 . . . RESPO!&IrC TO AIRPORT EQUI, .T FAILURES ] T1".7.9 RESPOV0G "TO HOST FAILURES DOT/FAA/AP

  18. Calculations of lightning-induced voltages in medium voltage distribution lines

    Energy Technology Data Exchange (ETDEWEB)

    Munhoz Rojas, Patricio E. [Instituto de Tecnologia para o Desenvolvimento (LACTEC/UFPR), Curitiba, PR (Brazil)], E-mail: patricio@lactec.org.br; Pinto, Cleverson Luiz da Silva [Companhia Paranaense de Energia (COPEL), Curitiba, PR (Brazil)], E-mail: cleverson@copel.com

    2007-07-01

    The objective of this paper is to show the results of a new computer program, written in Mat Lab environment, that is intended to calculate the lightning induced voltages in multi-conductor non-homogeneous lines, in order to be able to evaluate the impact of the usual protective measures implemented against lightning-induced disturbances. The main new features of this program are: a coupling model in terms of the scalar potentials referred to a remote ground was adopted; the coupling to the vertical conductors was considered in a manner similar to rest of the line; the describing equations were converted into a system of coupled ordinary differential equations, by a discretization only in space, which was subsequently solved using the powerful ODE solvers existing in Mat Lab. The validation of the new program has been performed by comparing its predicted results with other theoretical and computational results available in the literature and also with other experimental results published in the literature. It is shown that the agreement with other well established theoretical results is very good and, also, that the agreement between the newly calculated results and some published experimental results is better than previously obtained results. (author)

  19. Total Lightning Flash Activity Response to Aerosol over China Area

    Directory of Open Access Journals (Sweden)

    Pengguo Zhao

    2017-01-01

    Full Text Available Twelve years of measurements of aerosol optical depth (AOD, cloud fraction, cloud top height, ice cloud optical thickness and lightning flash density from 2001 to 2012 have been analyzed to investigate the effect of aerosols on electrical activity over an area of China. The results show that increasing aerosol loading inspires the convective intensity, and then increases the lightning flash density. The spatial distribution of the correlation between aerosol loading and electrical activity shows a remarkable regional difference over China. The high-correlation regions embody the positive aerosol microphysical effect on the intensity of the electrical activity, while the large-scale processes may play the main role in convection development and producing lightning in low-correlation regions.

  20. Estimation of the Current Peak Value Distribution of All Lightning to the Ground by Electro-Geometric Model

    Science.gov (United States)

    Sakata, Tadashi; Yamamoto, Kazuo; Sekioka, Shozo; Yokoyama, Shigeru

    When we examine the lightning frequency and the lightning shielding effect by EGM (electro-geometric model), we need the current distribution of all lightning to the ground. The lightning current distribution to structures is different from this distribution, but it has been used in EGM conventionally. We assumed the lightning striking distance coefficient related to height of structures for getting the result which corresponds to observed lightning frequency to structures, and estimated the current distribution of all lightning to the ground from data listed in IEC 62305 series by EGM. The estimated distribution adjusted by detection efficiency of LLS almost corresponded to observed distribution by LLS.

  1. Research on Line Patrol Strategy of 110kV Transmission Line after Lightning Strike

    Directory of Open Access Journals (Sweden)

    Li Mingjun

    2016-01-01

    Full Text Available Lightning faults occupy in the majority of instantaneous fault and reclosing can usually be successful, so power supply can be restored without immediate patrol in many cases. Firstly, this paper introduces the lightning fault positioning and identifying method. Then test electrical performance of insulators after lightning strike from 110kV lines. Data shows that lightning strike has little effect on the electric performance of insulator. Finally, illustrating disposal process of the 110 kV transmission line after lightning fault, certifying that the power supply reliability be ensured without line patrol.

  2. Fire Environment Mechanism of Lightning-groundfire for Daxing anling Mountains

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Ground fire is an igniting phenomenon that is difficult to control and lightning is the main cause of ground fire. The mechanism of lightning-ground fire is very complex. Daxing'anling Mountains forest region is the place that lighting-groundfire occurs more often and regularly. Our study on lightning-groundfire of this zone in 2002 shows: much more soil near the surface and the ground fuel is the matter preconditions of lightning-groundfire, and the weather conditions hasten the occurrence of lightning...

  3. 电子信息机房的雷灾调查分析%Diagnosis of Lightning Accident for Electronic Information Room

    Institute of Scientific and Technical Information of China (English)

    王涪德; 郑汉军; 黄延刚

    2014-01-01

    以对某电梯机房进行雷灾调查为例,对电梯机房遭受雷灾的可能性进行量化分析,找出雷电入侵的环节,并提出针对性的防护措施。总结了对电子信息系统进行雷灾调查的一般程序及方法,可为类似的机房调查提供参考。%Based on the example of electronic information room of elevator,this paper quantitatively analyzed the possibility of lightning accident for electronic information room.The steps of lightning invasion were found and the specific protective measures were put forward.The general procedure and methods of lightning accident diagnosis were summarized.It could provide references for lightning accident diagnosis of similar electronic information room.

  4. First results of the Colombia Lightning Mapping Array

    Science.gov (United States)

    López, Jesus; Montanyà, Joan; van der Velde, Oscar; Romero, David; Fabró, Ferran; Taborda, John; Aranguren, Daniel; Torres, Horacio

    2016-04-01

    In April 2015 the 3D Lightning Mapping Array (COLMA) network was installed on Santa Marta area (north of Colombia). The COLMA maps VHF radio emissions of lightning leaders in three dimensions by the time-of-arrival technique (Rison et al., 1999). This array has six sensors with base lines between 5 km to 20 km. The COLMA is the first VHF 3D network operating in the tropics and it has been installed in the frame of ASIM (Atmosphere-Space Interactions Monitor) ESA's mission in order to investigate the electrical characteristics of tropical thunderstorms favorable for the production of Terrestrial Gamma ray Flashes (TGF). In this paper we present COLMA data of several storms. We discuss lightning activity, lightning leader altitudes and thunderstorm charge structures compared to data form our ELMA (Ebro Lightning Mapping Array) at the north-east coast of Spain. The data confirm what we expected, lightning leaders can propagate at higher altitudes compared to mid latitude thunderstorms because the higher vertical development of tropical thunderstorms. A simple inspection of a ten minute period of the 16th of November of 2015 storm shows a tripolar electric charge structure. In that case, the midlevel negative charge region was located between 7 to 9 km. The structure presented a lower positive charge below the midlevel negative and centred at 6.5 km and an upper positive charge region extending from 9 km to slightly more than 15 km. This vertical extension of the upper positive charge where negative leaders evolve is significantly larger compared to the storms at the ELMA area in Spain. COLMA has shown frequent activity of negative leaders reaching altitudes of more than 15 km.

  5. Recent Developments With the New Mexico Tech Lightning Mapping Array

    Science.gov (United States)

    Krehbiel, P. R.; Rison, W. R.; Thomas, R. J.; Edens, H. E.; Aulich, G. D.

    2005-12-01

    Lightning mapping arrays (LMAs) are being operated by NASA in northern Alabama, by the University of Oklahoma and National Severe Storms Laboratory in central Oklahoma, and at Langmuir Laboratory and most recently at White Sands Missile Range in central and south-central New Mexico. In addition we have been developing a portable mapping system for use in field and demonstration programs. Data from the permanently-installed systems are being processed in real time and, in addition to research studies, are being used or are starting to be used in weather nowcasting applications. New metric-based code and algorithms have been developed for optimally processing the time-of-arrival measurements, which provide better solutions in less time than our previous code and have given us new insights into the basic processing issues. We are continuing to develop new techniques and approaches for analyzing the mapping data, such as using them to infer storm charge structure and for determining the direction and speed of initial breakdown of individual flashes, and combining the results with simple theoretical models for electrification and lightning initiation studies. We have also been working to obtain detailed pictures of individual lightning discharges using a compact array having 10-microsecond time resolution at Langmuir Laboratory and to combine these data with slow and fast electric field change measurements to advance our understanding of basic breakdown processes. Finally, the portable LMA will provide new and unique opportunities for studies of convective storms and lightning, such as fully mobile field campaigns, studies of lightning initiation in conjunction with cosmic ray and high energy particle observations, and the development of techniques and systems for monitoring lightning in urban and noisy metropolitan areas.

  6. Lightning climatology in the Congo Basin: detailed analysis

    Science.gov (United States)

    Soula, Serge; Kigotsi, Jean; Georgis, Jean-François; Barthe, Christelle

    2016-04-01

    The lightning climatology of the Congo Basin including several countries of Central Africa is analyzed in detail for the first time. It is based on World Wide Lightning Location Network (WWLLN) data for the period from 2005 to 2013. A comparison of these data with the Lightning Imaging Sensor (LIS) data for the same period shows the WWLLN detection efficiency (DE) in the region increases from about 1.70 % in the beginning of the period to 5.90 % in 2013, relative to LIS data, but not uniformly over the whole 2750 km × 2750 km area. Both the annual flash density and the number of stormy days show sharp maximum values localized in eastern of Democratic Republic of Congo (DRC) and west of Kivu Lake, regardless of the reference year and the period of the year. These maxima reach 12.86 fl km-2 and 189 days, respectively, in 2013, and correspond with a very active region located at the rear of the Virunga mountain range characterised with summits that can reach 3000 m. The presence of this range plays a role in the thunderstorm development along the year. The estimation of this local maximum of the lightning density by taking into account the DE, leads to a value consistent with that of the global climatology by Christian et al. (2003) and other authors. Thus, a mean maximum value of about 157 fl km-2 y-1 is found for the annual lightning density. The zonal distribution of the lightning flashes exhibits a maximum between 1°S and 2°S and about 56 % of the flashes located below the equator in the 10°S - 10°N interval. The diurnal evolution of the flash rate has a maximum between 1400 and 1700 UTC, according to the reference year, in agreement with previous works in other regions of the world.

  7. Relationship between lightning activity and vertical airflow characteristics in thunderstorms

    Science.gov (United States)

    Wang, Chenxi; Zheng, Dong; Zhang, Yijun; Liu, Liping

    2017-07-01

    Cloud-to-ground (CG) lightning data, wind field data derived from dual-Doppler radars, and radar reflectivity data are combined to investigate the relationships between CG lightning and the parameters associated with vertical airflow. A new method for the identification of thunderstorm cells based on the aggregation of flashes is developed. It is found that approximately 79.1% of CG flashes are located in the region featuring weak vertical velocity at the 0 °C level, ranging from - 5 to 5 m s- 1, with the majority in the weak updraft region, especially for negative CG lightning and the CG lightning in the initial stage of thunderstorms. The CG lightning rate is correlated with the volume of updraft for vertical velocities within certain limits. The sum of absolute precipitation ice mass flux in the region from 7 to 11 km is more significantly correlated with the CG flash rate, with correlation coefficients of 0.73, 0.71, and 0.74 for the initial, mature, and dissipating stages of thunderstorms, respectively. On average, the updraft in the thunderstorm at the stage when the last CG flash occurs accounts for a much smaller ratio to the whole volume of the thunderstorm than that corresponding to the first CG flash. The maximum updraft and maximum height of the 10 and 20 m s- 1 updraft speeds are close for the first and last CG flashes, indicating the dependence of the lightning on strength of updraft. It is deduced that layered large-range charges may be more conducive to the generation of CG flashes than charge pockets in the thunderstorm.

  8. Lightning electromagnetic field generated by grounding electrode considering soil ionization

    Institute of Scientific and Technical Information of China (English)

    ZENG Rong; HE Jinliang; ZHANG Bo; GAO Yanqing

    2006-01-01

    A circuit model with lumped time-variable parameter is proposed to calculate the transient characteristic of grounding electrode under lightning current, which takes into consideration the dynamic and nonlinear effect of soil ionization around the grounding electrode. The ionization phenomena in the soil are simulated by means of time-variable parameters under appropriate conditions. The generated electromagnetic field in the air is analyzed by using electrical dipole theory and image theory when the lightning current flows into the grounding electrode. The influence of soil ionization on the electromagnetic field is investigated.

  9. A possible relationship between Global Warming and Lightning Activity in India during the period 1998-2009

    CERN Document Server

    B., Felix Pereira; Girish, T E

    2010-01-01

    Lightning activity on a global scale has been studied season wise using satellite data for the period from 1998 to 2009. Lightning activity shows an increasing trend during the period of study which is highly correlated with atmospheric warming. A similar increasing trend of lightning activity is observed in the Indian region during the pre-monsoon season which is correlated with global lightning trends and warming trends of surface temperature in India. Key words: Global warming, lightning activity, Solar cycle changes

  10. Evaluation of Horizontal Electric Field Under Different Lightning Current Models by Perfect Ground Assumption

    Institute of Scientific and Technical Information of China (English)

    LIANG Jianfeng; LI Yanming

    2012-01-01

    Lightning electromagnetics can affect the reliability of the power system or communication system.Therefore,evaluation of electromagnetic fields generated by lightning return stroke is indispensable.Arnold sommerfeld proposed a model to calculate the electromagnetic field,but it involved the time-consuming sommerfeld integral.However,perfect conductor ground assumption can account for fast calculation,thus this paper reviews the perfect ground equation for evaluation of lightning electromagnetic fields,presents three engineering lightning return stroke models,and calculates the horizontal electric field caused by three lightning return stroke models.According to the results,the amplitude of lightning return stroke has a strong impact on horizontal electric fields,and the steepness of lightning return stroke influences the horizontal electric fields.Moreover,the perfect ground method is faster than the sommerfeld integral method.

  11. Thunderbolt in biogeochemistry: galvanic effects of lightning as another source for metal remobilization.

    Science.gov (United States)

    Schaller, Jörg; Weiske, Arndt; Berger, Frank

    2013-11-04

    Iron and manganese are relevant constituents of the earth's crust and both show increasing mobility when reduced by free electrons. This reduction is known to be controlled by microbial dissimilation processes. Alternative sources of free electrons in nature are cloud-to-ground lightning events with thermal and galvanic effects. Where thermal effects of lightning events are well described, less is known about the impact of galvanic lightning effects on metal mobilization. Here we show that a significant mobilization of manganese occurs due to galvanic effects of both positive and negative lightning, where iron seems to be unaffected with manganese being abundant in oxic forms in soils/sediments. A mean of 0.025 mmol manganese (negative lightning) or 0.08 mmol manganese (positive lightning) mobilization may occur. We suggest that lightning possibly influences biogeochemical cycles of redox sensitive elements in continental parts of the tropics/subtropics on a regional/local scale.

  12. 49 CFR 23.45 - What are the requirements for submitting overall goal information to the FAA?

    Science.gov (United States)

    2010-10-01

    ... Transportation PARTICIPATION OF DISADVANTAGED BUSINESS ENTERPRISE IN AIRPORT CONCESSIONS Goals, Good Faith...-conscious means, respectively, and the basis for making this projection (see § 23.51(d)(5)) (g) FAA may approve or disapprove the way you calculated your goal, including your race-neutral/race-conscious “split...

  13. 14 CFR 11.21 - What are the most common kinds of rulemaking actions for which FAA follows the Administrative...

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false What are the most common kinds of rulemaking actions for which FAA follows the Administrative Procedure Act? 11.21 Section 11.21 Aeronautics... RULEMAKING PROCEDURES Rulemaking Procedures General § 11.21 What are the most common kinds of...

  14. The Consequences of the FAA not Offering Emergency Agricultural UAS Rules for Water Conservation During the 2012 Drought

    Science.gov (United States)

    Darling, R. G.

    2016-12-01

    The FAA's policies for agricultural Unmanned Aerial Systems (UAS) is essential towards preservation and optimization of water use in the parched Western United States. Had FAA applied emergency rules putting farmers on equal-footing with hobbyists for sUAS use at the beginning of the 2012 drought, the Western US could have been able to save approximately 3 Million/AF of water through improved irrigation management. For perspective, Los Angeles city's annual current consumption is 587,000 acre-feet. This study uses various assumptions about developed water use in agriculture and urban areas to determine water use, energy consumption, monetary loss through delay in FAA regulations. If the saved water was added to the ground the energy savings could have been approximately 1.27 Terra-Watt hours, enough energy to power the entire University of California system for 5 years. It remains unclear if new FAA regulations are sufficiently permissive to allow for widespread adoption of sUAS based precision agriculture. Substantial opportunities exist for utilizing UAS traffic management software in rural areas of less crowed airspace: incorporating geofencing and a notification system to operators and air traffic control as an alternative to a difficult examination process.

  15. 41 CFR 102-37.535 - What information must FAA provide to GSA on its administration of the public airport donation...

    Science.gov (United States)

    2010-07-01

    ... FAA provide to GSA on its administration of the public airport donation program? 102-37.535 Section... (Continued) FEDERAL MANAGEMENT REGULATION PERSONAL PROPERTY 37-DONATION OF SURPLUS PERSONAL PROPERTY Donations to Public Airports § 102-37.535 What information must FAA provide to GSA on its administration...

  16. Potential of convective rainfall estimation from lightning data in the context of the "Simulation of Meteosat Third Generation - Lightning Imager through Tropical Rainfall Measuring Mission - Lightning Imaging Sensor data

    Science.gov (United States)

    Biron, D.; de Leonibus, L.; Zauli, F.; Melfi, D.; Laquale, P.; Labate, D.

    2009-04-01

    The Centro Nazionale di Meteorologia e Climatologia Aeronautica recently hosted a fellowship sponsored by Selex Galileo, with the intent to study and perform a simulation of Meteosat Third Generation - Lightning Imager (MTG-LI) sensor behavior through Tropical Rainfall Measuring Mission - Lightning Imaging Sensor data (TRMM-LIS). For the next generation of earth observation geostationary satellite, major operating agencies are planning to insert an optical imaging mission, that continuously observes lightning pulses in the atmosphere; EUMETSAT has decided in recent years that one of the candidate mission to be flown on MTG is LI, a Lightning Imager. MTG-LI mission has no Meteosat Second Generation heritage, but users need to evaluate the possible real time data output of the instrument to agree in inserting it on MTG payload. Authors took the expected LI design from MTG Mission Requirement Document, and reprocess real lightning dataset, acquired from space by TRMM-LIS instrument, to produce a simulated MTG-LI lightning dataset. The simulation is performed in several run, varying Minimum Detectable Energy, taking into account processing steps from event detection to final lightning information. A definition of the specific meteorological requirements is given from the potential use in meteorology of lightning final information for convection estimation and numerical cloud modeling. Study results show the range of instrument requirements relaxation which lead to minimal reduction in the final lightning information. Potential in convective rainfall estimation over ocean from space lightning observation is addressed and a retrieval example making use of lightning ground network data is reported both with validation by radar observation.

  17. Does a sixth mechanism exist to explain lightning injuries?: investigating a possible new injury mechanism to determine the cause of injuries related to close lightning flashes.

    Science.gov (United States)

    Blumenthal, Ryan; Jandrell, Ian R; West, Nicholas J

    2012-09-01

    Five mechanisms have been described in the literature regarding lightning injury mechanisms. A sixth mechanism is proposed in this article, namely, lightning barotrauma. A simple laboratory experiment was conducted using ordnance gelatin for ballistic studies. Lightning was simulated in a high-voltage laboratory using an 8/20-microsecond current impulse generator and discharged through ballistic gel. Temporary and permanent cavity formations were confirmed. The cavities formed were directly proportional to the currents used. Findings suggest that a sixth mechanism of lightning injury, namely, barotrauma, should be considered.

  18. Location accuracy evaluation of lightning location systems using natural lightning flashes recorded by a network of high-speed cameras

    Science.gov (United States)

    Alves, J.; Saraiva, A. C. V.; Campos, L. Z. D. S.; Pinto, O., Jr.; Antunes, L.

    2014-12-01

    This work presents a method for the evaluation of location accuracy of all Lightning Location System (LLS) in operation in southeastern Brazil, using natural cloud-to-ground (CG) lightning flashes. This can be done through a multiple high-speed cameras network (RAMMER network) installed in the Paraiba Valley region - SP - Brazil. The RAMMER network (Automated Multi-camera Network for Monitoring and Study of Lightning) is composed by four high-speed cameras operating at 2,500 frames per second. Three stationary black-and-white (B&W) cameras were situated in the cities of São José dos Campos and Caçapava. A fourth color camera was mobile (installed in a car), but operated in a fixed location during the observation period, within the city of São José dos Campos. The average distance among cameras was 13 kilometers. Each RAMMER sensor position was determined so that the network can observe the same lightning flash from different angles and all recorded videos were GPS (Global Position System) time stamped, allowing comparisons of events between cameras and the LLS. The RAMMER sensor is basically composed by a computer, a Phantom high-speed camera version 9.1 and a GPS unit. The lightning cases analyzed in the present work were observed by at least two cameras, their position was visually triangulated and the results compared with BrasilDAT network, during the summer seasons of 2011/2012 and 2012/2013. The visual triangulation method is presented in details. The calibration procedure showed an accuracy of 9 meters between the accurate GPS position of the object triangulated and the result from the visual triangulation method. Lightning return stroke positions, estimated with the visual triangulation method, were compared with LLS locations. Differences between solutions were not greater than 1.8 km.

  19. Aerosols and lightning activity: The effect of vertical profile and aerosol type

    Science.gov (United States)

    Proestakis, E.; Kazadzis, S.; Lagouvardos, K.; Kotroni, V.; Amiridis, V.; Marinou, E.; Price, C.; Kazantzidis, A.

    2016-12-01

    The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument on board the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite has been utilized for the first time in a study regarding lightning activity modulation due to aerosols. Lightning activity observations, obtained by the ZEUS long range Lightning Detection Network, European Centre for Medium range Weather Forecasts (ECMWF) Convective Available Potential Energy (CAPE) data and Cloud Fraction (CF) retrieved by MODIS on board Aqua satellite have been combined with CALIPSO CALIOP data over the Mediterranean basin and for the period March to November, from 2007 to 2014. The results indicate that lightning activity is enhanced during days characterized by higher Aerosol Optical Depth (AOD) values, compared to days with no lightning. This study contributes to existing studies on the link between lightning activity and aerosols, which have been based just on columnar AOD satellite retrievals, by performing a deeper analysis into the effect of aerosol profiles and aerosol types. Correlation coefficients of R = 0.73 between the CALIPSO AOD and the number of lightning strikes detected by ZEUS and of R = 0.93 between ECMWF CAPE and lightning activity are obtained. The analysis of extinction coefficient values at 532 nm indicates that at an altitudinal range exists, between 1.1 km and 2.9 km, where the values for extinction coefficient of lightning-active and non-lightning-active cases are statistically significantly different. Finally, based on the CALIPSO aerosol subtype classification, we have investigated the aerosol conditions of lightning-active and non-lightning-active cases. According to the results polluted dust aerosols are more frequently observed during non-lightning-active days, while dust and smoke aerosols are more abundant in the atmosphere during the lightning-active days.

  20. Climatology of lightning activity in South China and its relationships to precipitation and convective available potential energy

    Science.gov (United States)

    Zheng, Dong; Zhang, Yijun; Meng, Qing; Chen, Luwen; Dan, Jianru

    2016-03-01

    This study examined lightning activity and its relationship to precipitation and convective available potential energy (CAPE) in South China during 2001-12, based on data from the Guangdong Lightning Location System, the Tropical Rainfall Measuring Mission satellite, and the ERA-Interim dataset. Two areas of high lightning density are identified: one over the Pearl River Delta, and the other to the north of Leizhou Peninsula. Large peak-current cloud-to-ground (LPCCG) lightning (>75 kA) shows weaker land-offshore contrasts than total CG lightning, in which negative cloud-to-ground (NCG) lightning occurs more prominently than positive cloud-to-ground (PCG) lightning on land. While the frequency of total CG lightning shows a main peak in June and a second peak in August, the LPCCG lightning over land shows only a single peak in June. The ratio of positive LPCCG to total lightning is significantly greater during February-April than during other times of the year. Diurnally, CG lightning over land shows only one peak in the afternoon, whereas CG lightning offshore shows morning and afternoon peaks. The rain yield per flash is on the order of 107-108 kg per flash across the analysis region, and its spatial distribution is opposite to that of lightning density. Our data show that lightning activity over land is more sensitive than that over offshore waters to CAPE. The relationships between lightning activity and both precipitation and CAPE are associated with convection activity in the analysis region.