WorldWideScience

Sample records for high voltage distribution

  1. DISTRIBUTION OF HIGH-FREQUENCY VOLTAGE IN DISTRIBUTION NETWORK

    Directory of Open Access Journals (Sweden)

    M. I. Polujanov

    2005-01-01

    Full Text Available The paper reveals a method for remote determination of a location of single-phase short circuit on the ground in distribution networks with isolated neutral point. The method is based on measurement of high-frequency (a tone  range inter-phase voltage at all transformer substations and it creates preconditions for automation of searching process.  

  2. A STUDY ON LOSS & COST MINIMIZATION BY USING HIGH VOLTAGE DISTRIBUTION SYSTEM

    OpenAIRE

    P. Hussain Khan*, Ch. Punya Sekhar

    2016-01-01

    This paper presents a converter free system to improve the loss minimization and to reduce the cost of power distribution. The high voltage distribution system is implemented to reduce the loss in the present distribution system. The detailed cost estimation and loss minimization in high voltage distribution system is calculated through simulation results. These performance analysis are presented in this paper.      

  3. Enhanced Local Grid Voltage Support Method for High Penetration of Distributed Generators

    DEFF Research Database (Denmark)

    Demirok, Erhan; Sera, Dezso; Rodriguez, Pedro

    2011-01-01

    Grid voltage rise and thermal loading of network components are the most remarkable barriers to allow high number of distributed generator (DG) connections on the medium voltage (MV) and low voltage (LV) electricity networks. The other barriers such as grid power quality (harmonics, voltage...... unbalance, flicker etc.) and network protection mechanisms can be figured out once the maximum DG connection capacity of the network is reached. In this paper, additional reactive power reserve of inverter interfaced DGs is exploited to lower the grid voltage level by means of location-adaptive Q(U) droop...... function. The proposed method aims to achieve less grid voltage violations thus more DG connection on the electricity distribution networks can be allowed....

  4. Distributed Control of Battery Energy Storage Systems for Voltage Regulation in Distribution Networks with High PV Penetration

    DEFF Research Database (Denmark)

    Zeraati, Mehdi; Golshan, Mohamad Esmaeil Hamedani; Guerrero, Josep M.

    2017-01-01

    issues of distribution networks. In this paper, the battery energy storage (BES) systems are used in order to solve the voltage rise during the peak PV generation as well as the voltage drop while meeting the peak load. A coordinated control strategy is proposed to regulate the charge/discharge of BESs......The voltage rise problem in low voltage (LV) distribution networks with high penetration of photovoltaic (PV) resources is one of the most important challenges in the development of these renewable resources since it may prevent the maximum PV penetration considering the reliability and security...... using a combination of the local droop based control method and a distributed control scheme which ensures the voltages of feeder remain within allowed limits. Therefore, two different consensus algorithms are used: The first algorithm determines the BESs participation in voltage regulation in terms...

  5. Voltage management of distribution networks with high penetration of distributed photovoltaic generation sources

    Science.gov (United States)

    Alyami, Saeed

    Installation of photovoltaic (PV) units could lead to great challenges to the existing electrical systems. Issues such as voltage rise, protection coordination, islanding detection, harmonics, increased or changed short-circuit levels, etc., need to be carefully addressed before we can see a wide adoption of this environmentally friendly technology. Voltage rise or overvoltage issues are of particular importance to be addressed for deploying more PV systems to distribution networks. This dissertation proposes a comprehensive solution to deal with the voltage violations in distribution networks, from controlling PV power outputs and electricity consumption of smart appliances in real time to optimal placement of PVs at the planning stage. The dissertation is composed of three parts: the literature review, the work that has already been done and the future research tasks. An overview on renewable energy generation and its challenges are given in Chapter 1. The overall literature survey, motivation and the scope of study are also outlined in the chapter. Detailed literature reviews are given in the rest of chapters. The overvoltage and undervoltage phenomena in typical distribution networks with integration of PVs are further explained in Chapter 2. Possible approaches for voltage quality control are also discussed in this chapter, followed by the discussion on the importance of the load management for PHEVs and appliances and its benefits to electric utilities and end users. A new real power capping method is presented in Chapter 3 to prevent overvoltage by adaptively setting the power caps for PV inverters in real time. The proposed method can maintain voltage profiles below a pre-set upper limit while maximizing the PV generation and fairly distributing the real power curtailments among all the PV systems in the network. As a result, each of the PV systems in the network has equal opportunity to generate electricity and shares the responsibility of voltage

  6. Voltage Based Detection Method for High Impedance Fault in a Distribution System

    Science.gov (United States)

    Thomas, Mini Shaji; Bhaskar, Namrata; Prakash, Anupama

    2016-09-01

    High-impedance faults (HIFs) on distribution feeders cannot be detected by conventional protection schemes, as HIFs are characterized by their low fault current level and waveform distortion due to the nonlinearity of the ground return path. This paper proposes a method to identify the HIFs in distribution system and isolate the faulty section, to reduce downtime. This method is based on voltage measurements along the distribution feeder and utilizes the sequence components of the voltages. Three models of high impedance faults have been considered and source side and load side breaking of the conductor have been studied in this work to capture a wide range of scenarios. The effect of neutral grounding of the source side transformer is also accounted in this study. The results show that the algorithm detects the HIFs accurately and rapidly. Thus, the faulty section can be isolated and service can be restored to the rest of the consumers.

  7. Preparation of Power Distribution System for High Penetration of Renewable Energy Part I. Dynamic Voltage Restorer for Voltage Regulation Pat II. Distribution Circuit Modeling and Validation

    Science.gov (United States)

    Khoshkbar Sadigh, Arash

    Part I: Dynamic Voltage Restorer In the present power grids, voltage sags are recognized as a serious threat and a frequently occurring power-quality problem and have costly consequence such as sensitive loads tripping and production loss. Consequently, the demand for high power quality and voltage stability becomes a pressing issue. Dynamic voltage restorer (DVR), as a custom power device, is more effective and direct solutions for "restoring" the quality of voltage at its load-side terminals when the quality of voltage at its source-side terminals is disturbed. In the first part of this thesis, a DVR configuration with no need of bulky dc link capacitor or energy storage is proposed. This fact causes to reduce the size of the DVR and increase the reliability of the circuit. In addition, the proposed DVR topology is based on high-frequency isolation transformer resulting in the size reduction of transformer. The proposed DVR circuit, which is suitable for both low- and medium-voltage applications, is based on dc-ac converters connected in series to split the main dc link between the inputs of dc-ac converters. This feature makes it possible to use modular dc-ac converters and utilize low-voltage components in these converters whenever it is required to use DVR in medium-voltage application. The proposed configuration is tested under different conditions of load power factor and grid voltage harmonic. It has been shown that proposed DVR can compensate the voltage sag effectively and protect the sensitive loads. Following the proposition of the DVR topology, a fundamental voltage amplitude detection method which is applicable in both single/three-phase systems for DVR applications is proposed. The advantages of proposed method include application in distorted power grid with no need of any low-pass filter, precise and reliable detection, simple computation and implementation without using a phased locked loop and lookup table. The proposed method has been verified

  8. Voltage Support Study of Smart PV Inverters on a High-Photovoltaic Penetration Utility Distribution Feeder

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Fei; Pratt, Annabelle; Bialek, Tom; Bell, Frances; McCarty, Michael; Atef, Kahveh; Nagarajan, Adarsh; Gotseff, Peter

    2016-11-21

    This paper reports on tools and methodologies developed to study the impact of adding rooftop photovoltaic (PV) systems, with and without the ability to provide voltage support, on the voltage profile of distribution feeders. Simulation results are provided from a study of a specific utility feeder. The simulation model of the utility distribution feeder was built in OpenDSS and verified by comparing the simulated voltages to field measurements. First, we set all PV systems to operate at unity power factor and analyzed the impact on feeder voltages. Then we conducted multiple simulations with voltage support activated for all the smart PV inverters. These included different constant power factor settings and volt/VAR controls.

  9. Dynamic voltage stability of a distribution system with high penetration of grid-connected photovoltaic type solar generators

    Directory of Open Access Journals (Sweden)

    Zetty Adibah Kamaruzzaman

    2016-06-01

    Full Text Available This paper presents the impact of grid-connected photovoltaic (PV generator on dynamic voltage stability of a power distribution system by considering solar intermittency, PV penetration level, and contingencies such as line outage and load increase. The IEEE 13 node test feeder is used as a test system, and a solar PV of 0.48 kV/0.5 MVA is integrated into the test system. Test results show that system voltage is stable at high PV penetration levels. Increase in load causes voltage instability, in which voltage drops below its allowable operating limit. Thus, increase in PV penetration level does not improve system voltage stability because the system experiences voltage collapse during line outage.

  10. Index-Based Assessment of Voltage Rise and Reverse Power Flow Phenomena in a Distribution Feeder Under High PV Penetration

    DEFF Research Database (Denmark)

    Hasheminamin, Maryam; Agelidis, Vassilios G.; Salehi, Vahid

    2015-01-01

    The proliferation of photovoltaic (PV) generation in low- and medium-voltage distribution networks is expected to continue. Qualified studies can quantify adverse impacts of high PV penetration on distribution networks and assist utilities in decision making. This paper proposes an index-based me......The proliferation of photovoltaic (PV) generation in low- and medium-voltage distribution networks is expected to continue. Qualified studies can quantify adverse impacts of high PV penetration on distribution networks and assist utilities in decision making. This paper proposes an index...... are used to confirm the effectiveness of the proposed indices. This paper derives the acceptable range of the proposed indices and safe margin, which have been compared with the basic active power curtailment method with no constraint, in order to avoid voltage rise. The IEEE 69-bus network is also...

  11. Demand Response in Low Voltage Distribution Networks with High PV Penetration

    DEFF Research Database (Denmark)

    Nainar, Karthikeyan; Pokhrel, Basanta Raj; Pillai, Jayakrishnan Radhakrishna

    2017-01-01

    generation and load forecasts, network topology and market price signals as inputs, limits of network voltages, line power flows, transformer loading and demand response dynamics as constraints to find the required demand response at each time step. The proposed method can be used by the DSOs to purchase...... the required flexibility from the electricity market through an aggregator. The optimum demand response enables consumption of maximum renewable energy within the network constraints. Simulation studies are conducted using Matlab and DigSilent Power factory software on a Danish low-voltage distribution system...

  12. Technological Aspects: High Voltage

    CERN Document Server

    Faircloth, D.C.

    2013-12-16

    This paper covers the theory and technological aspects of high-voltage design for ion sources. Electric field strengths are critical to understanding high-voltage breakdown. The equations governing electric fields and the techniques to solve them are discussed. The fundamental physics of high-voltage breakdown and electrical discharges are outlined. Different types of electrical discharges are catalogued and their behaviour in environments ranging from air to vacuum are detailed. The importance of surfaces is discussed. The principles of designing electrodes and insulators are introduced. The use of high-voltage platforms and their relation to system design are discussed. The use of commercially available high-voltage technology such as connectors, feedthroughs and cables are considered. Different power supply technologies and their procurement are briefly outlined. High-voltage safety, electric shocks and system design rules are covered.

  13. High voltage engineering

    CERN Document Server

    Rizk, Farouk AM

    2014-01-01

    Inspired by a new revival of worldwide interest in extra-high-voltage (EHV) and ultra-high-voltage (UHV) transmission, High Voltage Engineering merges the latest research with the extensive experience of the best in the field to deliver a comprehensive treatment of electrical insulation systems for the next generation of utility engineers and electric power professionals. The book offers extensive coverage of the physical basis of high-voltage engineering, from insulation stress and strength to lightning attachment and protection and beyond. Presenting information critical to the design, selec

  14. High voltage test techniques

    CERN Document Server

    Kind, Dieter

    2001-01-01

    The second edition of High Voltage Test Techniques has been completely revised. The present revision takes into account the latest international developments in High Voltage and Measurement technology, making it an essential reference for engineers in the testing field.High Voltage Technology belongs to the traditional area of Electrical Engineering. However, this is not to say that the area has stood still. New insulating materials, computing methods and voltage levels repeatedly pose new problems or open up methods of solution; electromagnetic compatibility (EMC) or components and systems al

  15. Efficient kesterite solar cells with high open-circuit voltage for applications in powering distributed devices

    Science.gov (United States)

    Antunez, Priscilla D.; Bishop, Douglas M.; Luo, Yu; Haight, Richard

    2017-11-01

    Simultaneously achieving high voltage and high efficiency in thin-film solar cells is of paramount importance for real-world applications. While solar cells fabricated from the Earth-abundant kesterite absorber Cu2ZnSn(SxSe1-x)4 provide an attractive, non-toxic, energy harvesting solution, their utilization has been constrained by relatively low open-circuit voltages that limit efficiency. Increasing the sulfur content to widen the bandgap boosts the voltage, but usually at the expense of efficiency. Here, we report important progress on this fundamental problem by fabricating solar cells with high sulfur content that exhibit efficiencies up to 11.89% with open-circuit voltages as high as 670 mV. In a multistep process, fully functional solar cells are separated from their growth substrate, and a high-work-function back contact is subsequently deposited. With this approach, we fabricated a series-connected device that produces 5.7 V under 1 Sun illumination and 2 V under low lighting conditions, below 10-3 Suns.

  16. Control of Grid Interactive PV Inverters for High Penetration in Low Voltage Distribution Networks

    DEFF Research Database (Denmark)

    Demirok, Erhan

    distorted conditions. Chapter 2, therefore; overviews the latest ancillary services such as real power reduction during over frequency/over voltage events and reactive power control for static grid voltage support function of PV inverters. In case of high density of PV integration, grid connection rules...... of these inverters may depend on grid connection rules which are forced by DSOs. Minimum requirement expected from PV inverters is to transfer maximum power by taking direct current (DC) form from PV modules and release it into AC grid and also continuously keep the inverters synchronized to the grid even under...... widespread usage in residential areas and are usually single-phase connected to 230/400-V grid. Since realistic assessment of PV integration should include both single- and three-phase PV connections, a three-phase load flow script which is able to allow more precise estimation of PV hosting capacity...

  17. High voltage engineering fundamentals

    CERN Document Server

    Kuffel, E; Hammond, P

    1984-01-01

    Provides a comprehensive treatment of high voltage engineering fundamentals at the introductory and intermediate levels. It covers: techniques used for generation and measurement of high direct, alternating and surge voltages for general application in industrial testing and selected special examples found in basic research; analytical and numerical calculation of electrostatic fields in simple practical insulation system; basic ionisation and decay processes in gases and breakdown mechanisms of gaseous, liquid and solid dielectrics; partial discharges and modern discharge detectors; and over

  18. Voltage Weak DC Distribution Grids

    NARCIS (Netherlands)

    Hailu, T.G.; Mackay, L.J.; Ramirez Elizondo, L.M.; Ferreira, J.A.

    2017-01-01

    This paper describes the behavior of voltage weak DC distribution systems. These systems have relatively small system capacitance. The size of system capacitance, which stores energy, has a considerable effect on the value of fault currents, control complexity, and system reliability. A number of

  19. Coordinated Voltage Control of Distributed PV Inverters for Voltage Regulation in Low Voltage Distribution Networks

    DEFF Research Database (Denmark)

    Nainar, Karthikeyan; Pokhrel, Basanta Raj; Pillai, Jayakrishnan Radhakrishna

    2017-01-01

    This paper reviews and analyzes the existing voltage control methods of distributed solar PV inverters to improve the voltage regulation and thereby the hosting capacity of a low-voltage distribution network. A novel coordinated voltage control method is proposed based on voltage sensitivity...... optimization. The proposed method is used to calculate the voltage bands and droop settings of PV inverters at each node by the supervisory controller. The local controller of each PV inverter implements the volt/var control and if necessary, the active power curtailment as per the received settings and based...... on measured local voltages. The advantage of the proposed method is that the calculated reactive power and active power droop settings enable fair contribution of the PV inverters at each node to the voltage regulation. Simulation studies are conducted using DigSilent Power factory software on a simplified...

  20. Coordinated Voltage Control of Distributed PV Inverters for Voltage Regulation in Low Voltage Distribution Networks

    DEFF Research Database (Denmark)

    Nainar, Karthikeyan; Pokhrel, Basanta Raj; Pillai, Jayakrishnan Radhakrishna

    2017-01-01

    This paper reviews and analyzes the existing voltage control methods of distributed solar PV inverters to improve the voltage regulation and thereby the hosting capacity of a low-voltage distribution network. A novel coordinated voltage control method is proposed based on voltage sensitivity...... analysis, which is simple for computation and requires moderate automation and communication infrastructure. The proposed method is suitable for a hierarchical control structure where a supervisory controller has the provision to adapt the settings of local PV inverter controllers for overall system...

  1. Mitigation of Voltage Sags in CIGRE Low Voltage Distribution Network

    DEFF Research Database (Denmark)

    Mustafa, Ghullam; Bak-Jensen, Birgitte; Mahat, Pukar

    2013-01-01

    problems in the distribution system. The voltage problems dealt with in this paper are to show how to mitigate voltage sags in the CIGRE Low Voltage (LV) test network and networks like this. The voltage sags, for the tested cases in the CIGRE LV test network are mainly due to three phase faults....... The compensation of voltage sags in the different parts of CIGRE distribution network is done by using the four STATCOM compensators already existing in the test grid. The simulations are carried out in DIgSILENT power factory software version 15.0.......Any problem in voltage in a power network is undesirable as it aggravates the quality of the power. Power electronic devices such as Voltage Source Converter (VSC) based Static Synchronous Compensator (STATCOM), Dynamic Voltage Restorer (DVR) etc. are commonly used for the mitigation of voltage...

  2. Transient voltage sharing in series-coupled high voltage switches

    Directory of Open Access Journals (Sweden)

    Editorial Office

    1992-07-01

    Full Text Available For switching voltages in excess of the maximum blocking voltage of a switching element (for example, thyristor, MOSFET or bipolar transistor such elements are often coupled in series - and additional circuitry has to be provided to ensure equal voltage sharing. Between each such series element and system ground there is a certain parasitic capacitance that may draw a significant current during high-speed voltage transients. The "open" switch is modelled as a ladder network. Analy­sis reveals an exponential progression in the distribution of the applied voltage across the elements. Overstressing thus oc­curs in some of the elements at levels of the total voltage that are significantly below the design value. This difficulty is overcome by grading the voltage sharing circuitry, coupled in parallel with each element, in a prescribed manner, as set out here.

  3. High Voltage Seismic Generator

    Science.gov (United States)

    Bogacz, Adrian; Pala, Damian; Knafel, Marcin

    2015-04-01

    This contribution describes the preliminary result of annual cooperation of three student research groups from AGH UST in Krakow, Poland. The aim of this cooperation was to develop and construct a high voltage seismic wave generator. Constructed device uses a high-energy electrical discharge to generate seismic wave in ground. This type of device can be applied in several different methods of seismic measurement, but because of its limited power it is mainly dedicated for engineering geophysics. The source operates on a basic physical principles. The energy is stored in capacitor bank, which is charged by two stage low to high voltage converter. Stored energy is then released in very short time through high voltage thyristor in spark gap. The whole appliance is powered from li-ion battery and controlled by ATmega microcontroller. It is possible to construct larger and more powerful device. In this contribution the structure of device with technical specifications is resented. As a part of the investigation the prototype was built and series of experiments conducted. System parameter was measured, on this basis specification of elements for the final device were chosen. First stage of the project was successful. It was possible to efficiently generate seismic waves with constructed device. Then the field test was conducted. Spark gap wasplaced in shallowborehole(0.5 m) filled with salt water. Geophones were placed on the ground in straight line. The comparison of signal registered with hammer source and sparker source was made. The results of the test measurements are presented and discussed. Analysis of the collected data shows that characteristic of generated seismic signal is very promising, thus confirms possibility of practical application of the new high voltage generator. The biggest advantage of presented device after signal characteristics is its size which is 0.5 x 0.25 x 0.2 m and weight approximately 7 kg. This features with small li-ion battery makes

  4. High-voltage engineering and testing

    CERN Document Server

    Ryan, Hugh M

    2013-01-01

    This 3rd edition of High Voltage Engineering Testing describes strategic developments in the field and reflects on how they can best be managed. All the key components of high voltage and distribution systems are covered including electric power networks, UHV and HV. Distribution systems including HVDC and power electronic systems are also considered.

  5. Intelligent Distribution Voltage Control with Distributed Generation =

    Science.gov (United States)

    Castro Mendieta, Jose

    In this thesis, three methods for the optimal participation of the reactive power of distributed generations (DGs) in unbalanced distributed network have been proposed, developed, and tested. These new methods were developed with the objectives of maintain voltage within permissible limits and reduce losses. The first method proposes an optimal participation of reactive power of all devices available in the network. The propose approach is validated by comparing the results with other methods reported in the literature. The proposed method was implemented using Simulink of Matlab and OpenDSS. Optimization techniques and the presentation of results are from Matlab. The co-simulation of Electric Power Research Institute's (EPRI) OpenDSS program solves a three-phase optimal power flow problem in the unbalanced IEEE 13 and 34-node test feeders. The results from this work showed a better loss reduction compared to the Coordinated Voltage Control (CVC) method. The second method aims to minimize the voltage variation on the pilot bus on distribution network using DGs. It uses Pareto and Fuzzy-PID logic to reduce the voltage variation. Results indicate that the proposed method reduces the voltage variation more than the other methods. Simulink of Matlab and OpenDSS is used in the development of the proposed approach. The performance of the method is evaluated on IEEE 13-node test feeder with one and three DGs. Variables and unbalanced loads are used, based on real consumption data, over a time window of 48 hours. The third method aims to minimize the reactive losses using DGs on distribution networks. This method analyzes the problem using the IEEE 13-node test feeder with three different loads and the IEEE 123-node test feeder with four DGs. The DGs can be fixed or variables. Results indicate that integration of DGs to optimize the reactive power of the network helps to maintain the voltage within the allowed limits and to reduce the reactive power losses. The thesis is

  6. High Voltage Charge Pump

    KAUST Repository

    Emira, Ahmed A.

    2014-10-09

    Various embodiments of a high voltage charge pump are described. One embodiment is a charge pump circuit that comprises a plurality of switching stages each including a clock input, a clock input inverse, a clock output, and a clock output inverse. The circuit further comprises a plurality of pumping capacitors, wherein one or more pumping capacitors are coupled to a corresponding switching stage. The circuit also comprises a maximum selection circuit coupled to a last switching stage among the plurality of switching stages, the maximum selection circuit configured to filter noise on the output clock and the output clock inverse of the last switching stage, the maximum selection circuit further configured to generate a DC output voltage based on the output clock and the output clock inverse of the last switching stage.

  7. Plasma sheath effects and voltage distributions of large high-power satellite solar arrays

    Science.gov (United States)

    Parker, L. W.

    1979-01-01

    Knowledge of the floating voltage configuration of a large array in orbit is needed in order to estimate various plasma-interaction effects. The equilibrium configuration of array voltages relative to space depends on the sheath structure. The latter dependence for an exposed array is examined in the light of two finite-sheath effects. One effect is that electron currents may be seriously underestimated. The other is that a potential barrier for electrons can occur, restricting electron currents. A conducting surface is assumed on the basis of a conductivity argument. Finite-sheath effects are investigated. The results of assuming thin-sheath and thick-sheath limits on the floating configuration of a linearly connected array are studied. Sheath thickness and parasitic power leakage are estimated. Numerically computed fields using a 3-D code are displayed in the thick-sheath limit.

  8. Low power, scalable multichannel high voltage controller

    Science.gov (United States)

    Stamps, James Frederick [Livermore, CA; Crocker, Robert Ward [Fremont, CA; Yee, Daniel Dadwa [Dublin, CA; Dils, David Wright [Fort Worth, TX

    2008-03-25

    A low voltage control circuit is provided for individually controlling high voltage power provided over bus lines to a multitude of interconnected loads. An example of a load is a drive for capillary channels in a microfluidic system. Control is distributed from a central high voltage circuit, rather than using a number of large expensive central high voltage circuits to enable reducing circuit size and cost. Voltage is distributed to each individual load and controlled using a number of high voltage controller channel switches connected to high voltage bus lines. The channel switches each include complementary pull up and pull down photo isolator relays with photo isolator switching controlled from the central high voltage circuit to provide a desired bus line voltage. Switching of the photo isolator relays is further controlled in each channel switch using feedback from a resistor divider circuit to maintain the bus voltage swing within desired limits. Current sensing is provided using a switched resistive load in each channel switch, with switching of the resistive loads controlled from the central high voltage circuit.

  9. Deployment of low-voltage regulator considering existing voltage control in medium-voltage distribution systems

    Directory of Open Access Journals (Sweden)

    Hiroshi Kikusato

    2016-01-01

    Full Text Available Many photovoltaic (PV systems have been installed in distribution systems. This installation complicates the maintenance of all voltages within the appropriate range in all low-voltage distribution systems (LVDSs because the trends in voltage fluctuation differ in each LVDS. The installation of a low-voltage regulator (LVR that can accordingly control the voltage in each LVDS has been studied as a solution to this problem. Voltage control in a medium-voltage distribution system must be considered to study the deployment of LVRs. In this study, we installed LVRs in the LVDSs in which the existing voltage-control scheme cannot prevent voltage deviation and performed a numerical simulation by using a distribution system model with PV to evaluate the deployment of the LVRs.

  10. High voltage variable diameter insulator

    Science.gov (United States)

    Vanecek, David L.; Pike, Chester D.

    1984-01-01

    A high voltage feedthrough assembly (10) having a tubular insulator (15) extending between the ground plane ring (16) and the high voltage ring (30). The insulator (15) is made of Pyrex and decreases in diameter from the ground plane ring (16) to the high voltage ring (30), producing equipotential lines almost perpendicular to the wall (27) of the insulator (15) to optimize the voltage-holding capability of the feedthrough assembly (10).

  11. Mitigation of Unbalanced Voltage Sags and Voltage Unbalance in CIGRE Low Voltage Distribution Network

    DEFF Research Database (Denmark)

    Mustafa, Ghullam; Bak-Jensen, Birgitte; Mahat, Pukar

    2013-01-01

    . The voltage problems dealt with in this paper are to show how to mitigate unbalanced voltage sags and voltage unbalance in the CIGRE Low Voltage (LV) test network and net-works like this. The voltage unbalances, for the tested cases in the CIGRE LV test network are mainly due to single phase loads and due...... to unbalanced faults. The compensation of unbalanced voltage sags and voltage unbalance in the CIGRE distribution network is done by using the four STATCOM compensators already existing in the test grid. The simulations are carried out in DIgSILENT power factory software version 15.0.......Any problem with voltage in a power network is undesirable as it aggravates the quality of the power. Power electronic devices such as Voltage Source Converter (VSC) based Static Synchronous Compensator (STATCOM) etc. can be used to mitigate the voltage problems in the distribution system...

  12. Demand Response in Low Voltage Distribution Networks with High PV Penetration

    DEFF Research Database (Denmark)

    Nainar, Karthikeyan; Pokhrel, Basanta Raj; Pillai, Jayakrishnan Radhakrishna

    2017-01-01

    . Simulation results show that the proposed method is effective for calculating the optimum demand response. From the test scenarios, it is inferred that absorption of renewable energy from PV increased by 38% applying optimum demand response during the evaluation period in the studied distribution network....

  13. A distributed parameter model of transmission line transformer for high voltage nanosecond pulse generation.

    Science.gov (United States)

    Li, Jiangtao; Zhao, Zheng; Li, Longjie; He, Jiaxin; Li, Chenjie; Wang, Yifeng; Su, Can

    2017-09-01

    A transmission line transformer has potential advantages for nanosecond pulse generation including excellent frequency response and no leakage inductance. The wave propagation process in a secondary mode line is indispensable due to an obvious inside transient electromagnetic transition in this scenario. The equivalent model of the transmission line transformer is crucial for predicting the output waveform and evaluating the effects of magnetic cores on output performance. However, traditional lumped parameter models are not sufficient for nanosecond pulse generation due to the natural neglect of wave propagations in secondary mode lines based on a lumped parameter assumption. In this paper, a distributed parameter model of transmission line transformer was established to investigate wave propagation in the secondary mode line and its influential factors through theoretical analysis and experimental verification. The wave propagation discontinuity in the secondary mode line induced by magnetic cores is emphasized. Characteristics of the magnetic core under a nanosecond pulse were obtained by experiments. Distribution and formation of the secondary mode current were determined for revealing essential wave propagation processes in secondary mode lines. The output waveform and efficiency were found to be affected dramatically by wave propagation discontinuity in secondary mode lines induced by magnetic cores. The proposed distributed parameter model was proved more suitable for nanosecond pulse generation in aspects of secondary mode current, output efficiency, and output waveform. In depth, comprehension of underlying mechanisms and a broader view of the working principle of the transmission line transformer for nanosecond pulse generation can be obtained through this research.

  14. A distributed parameter model of transmission line transformer for high voltage nanosecond pulse generation

    Science.gov (United States)

    Li, Jiangtao; Zhao, Zheng; Li, Longjie; He, Jiaxin; Li, Chenjie; Wang, Yifeng; Su, Can

    2017-09-01

    A transmission line transformer has potential advantages for nanosecond pulse generation including excellent frequency response and no leakage inductance. The wave propagation process in a secondary mode line is indispensable due to an obvious inside transient electromagnetic transition in this scenario. The equivalent model of the transmission line transformer is crucial for predicting the output waveform and evaluating the effects of magnetic cores on output performance. However, traditional lumped parameter models are not sufficient for nanosecond pulse generation due to the natural neglect of wave propagations in secondary mode lines based on a lumped parameter assumption. In this paper, a distributed parameter model of transmission line transformer was established to investigate wave propagation in the secondary mode line and its influential factors through theoretical analysis and experimental verification. The wave propagation discontinuity in the secondary mode line induced by magnetic cores is emphasized. Characteristics of the magnetic core under a nanosecond pulse were obtained by experiments. Distribution and formation of the secondary mode current were determined for revealing essential wave propagation processes in secondary mode lines. The output waveform and efficiency were found to be affected dramatically by wave propagation discontinuity in secondary mode lines induced by magnetic cores. The proposed distributed parameter model was proved more suitable for nanosecond pulse generation in aspects of secondary mode current, output efficiency, and output waveform. In depth, comprehension of underlying mechanisms and a broader view of the working principle of the transmission line transformer for nanosecond pulse generation can be obtained through this research.

  15. Voltage Support from Electric Vehicles in Distribution Grid

    DEFF Research Database (Denmark)

    Huang, Shaojun; Pillai, Jayakrishnan Radhakrishna; Bak-Jensen, Birgitte

    2013-01-01

    The paper evaluates the voltage support functions from electric vehicles (EVs) on a typical Danish distribution grid with high EV penetration. In addition to the popular voltage control modes, such as voltage droop charging (low voltage level leads to low charging power) and reactive power support......, the combination of these two methods is also examined for controlled EV charging. Simulation results show that the combination of the two individual supporting methods has the best performance in terms of voltage regulation as well as improving EV penetration level at weak distribution grids....

  16. 30 CFR 75.804 - Underground high-voltage cables.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Underground high-voltage cables. 75.804 Section... AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution § 75.804 Underground high-voltage cables. (a) Underground high-voltage cables used in resistance...

  17. 30 CFR 77.810 - High-voltage equipment; grounding.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage equipment; grounding. 77.810... COAL MINES Surface High-Voltage Distribution § 77.810 High-voltage equipment; grounding. Frames, supporting structures, and enclosures of stationary, portable, or mobile high-voltage equipment shall be...

  18. Distribution System Voltage Regulation by Distributed Energy Resources

    Energy Technology Data Exchange (ETDEWEB)

    Ceylan, Oguzhan [ORNL; Liu, Guodong [ORNL; Xu, Yan [ORNL; Tomsovic, Kevin [University of Tennessee, Knoxville (UTK)

    2014-01-01

    This paper proposes a control method to regulate voltages in 3 phase unbalanced electrical distribution systems. A constrained optimization problem to minimize voltage deviations and maximize distributed energy resource (DER) active power output is solved by harmony search algorithm. IEEE 13 Bus Distribution Test System was modified to test three different cases: a) only voltage regulator controlled system b) only DER controlled system and c) both voltage regulator and DER controlled system. The simulation results show that systems with both voltage regulators and DER control provide better voltage profile.

  19. Measured Current Distribution Functions Describing an Array of High Voltage Needles Operating In the Avalanche and Streamer Modes

    Science.gov (United States)

    Wemlinger, Erik; Pedrow, Patrick; Garcia-Perez, Manuel; Ha, Su; Marin-Flores, Oscar; Pitts, Marvin

    2009-10-01

    It is hypothesized that cold plasma processing of small oxygenated molecules present in bio-oil will reduce coking in a catalytic steam reformer. The cold plasma reactor will be placed upstream of the reformer and will consist of an array of needles held at a DC voltage in the 5-10 kV range. The distribution of current pulses on each needle will be measured for gas mixtures consisting of varying amounts of argon, water, methanol, oxygen, and carbon dioxide. The small oxygenated hydrocarbon molecules from bio-oil can be reduced to hydrogen and synthesis gas by the catalytic steam reformer. However, the steam reforming of these oxygenated hydrocarbon molecules has a high tendency of coke formation. In this work, catalyst coking will be reduced by integrating the atmospheric pressure cold plasma reactor. Studying how distribution functions for elements in a small array (< 10 needles) ``interact'' will facilitate design of larger needle arrays that can be used for the commercial processing of biofuels.

  20. Calibration of Voltage Transformers and High- Voltage Capacitors at NIST

    Science.gov (United States)

    Anderson, William E.

    1989-01-01

    The National Institute of Standards and Technology (NIST) calibration service for voltage transformers and high-voltage capacitors is described. The service for voltage transformers provides measurements of ratio correction factors and phase angles at primary voltages up to 170 kV and secondary voltages as low as 10 V at 60 Hz. Calibrations at frequencies from 50–400 Hz are available over a more limited voltage range. The service for high-voltage capacitors provides measurements of capacitance and dissipation factor at applied voltages ranging from 100 V to 170 kV at 60 Hz depending on the nominal capacitance. Calibrations over a reduced voltage range at other frequencies are also available. As in the case with voltage transformers, these voltage constraints are determined by the facilities at NIST. PMID:28053409

  1. SYNTHESIS OF ACTIVE SCREENING SYSTEM OF MAGNETIC FIELD OF HIGH VOLTAGE POWER LINES OF DIFFERENT DESIGN TAKING INTO ACCOUNT SPATIAL AND TEMPORAL DISTRIBUTION OF MAGNETIC FIELD

    Directory of Open Access Journals (Sweden)

    B.I. Kuznetsov

    2017-04-01

    Full Text Available Purpose. Analyze the spatial and temporal distribution of the magnetic field of high voltage power lines with different design allowing and development of recommendations for the design of active screening systems by magnetic field of high voltage power lines. Methodology. Analysis of the spatial and temporal distribution of the magnetic field of high voltage power lines of different design allowing is made on the basis of Maxwell's equations solutions in the quasi-stationary approximation. Determination of the number, configuration, spatial arrangement and the compensation coil currents is formulated in the form of multiobjective optimization problem that is solved by multi-agent multiswarm stochastic optimization based on Pareto optimal solutions. Results of active screening system for the synthesis of various types of transmission lines with different numbers of windings controlled. The possibility of a significant reduction in the level of the flux density of the magnetic field source within a given region of space. Originality. For the first time an analysis of the spatial and temporal distribution of the magnetic field of power lines with different types and based on findings developed recommendations for the design of active screening system by magnetic field of high voltage power lines. Practical value. Practical recommendations on reasonable choice of the number and spatial arrangement of compensating windings of active screening system by magnetic field of high voltage power lines of different design allowing for the spatial and temporal distribution of the magnetic field. Results of active screening system synthesis of the magnetic field of industrial frequency generated by single-circuit 110 kV high voltage power lines with the supports have 330 - 1T «triangle» rotating magnetic field with full polarization in a residential five-storey building, located near the power lines. The system contains three compensating coil and reduces

  2. Coordinated Voltage Control of Active Distribution Network

    Directory of Open Access Journals (Sweden)

    Xie Jiang

    2016-01-01

    Full Text Available This paper presents a centralized coordinated voltage control method for active distribution network to solve off-limit problem of voltage after incorporation of distributed generation (DG. The proposed method consists of two parts, it coordinated primal-dual interior point method-based voltage regulation schemes of DG reactive powers and capacitors with centralized on-load tap changer (OLTC controlling method which utilizes system’s maximum and minimum voltages, to improve the qualified rate of voltage and reduce the operation numbers of OLTC. The proposed coordination has considered the cost of capacitors. The method is tested using a radial edited IEEE-33 nodes distribution network which is modelled using MATLAB.

  3. Modular High Voltage Power Supply

    Energy Technology Data Exchange (ETDEWEB)

    Newell, Matthew R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-05-18

    The goal of this project is to develop a modular high voltage power supply that will meet the needs of safeguards applications and provide a modular plug and play supply for use with standard electronic racks.

  4. Voltage control in active, intelligent low-voltage distribution networks; Spannungshaltung in aktiven, intelligenten Niederspannungsnetzen

    Energy Technology Data Exchange (ETDEWEB)

    Buelo, Thorsten; Mende, Denis [SMA Solar Technology AG, Niestetal (Germany); Geibel, Dominik [Fraunhofer Institut fuer Windenergie und Energiesystemtechnik (IWES), Kassel (Germany)] [and others

    2012-07-01

    This paper describes approaches for the voltage control in low-voltage distribution networks with a high share of distributed energy resources (DER). Taken into account are devices such as distribution transformers with on-load tap changer (OLTC), photovoltaic-inverters with reactive power capability and electronic voltage controllers (EVC). After a short description regarding voltage control, the devices and selected system concepts as well as the advantages and disadvantages of the different devices are described. Finally, the system-concepts are compared using the example of a real low voltage network, taking into account the possible increase of hosting capacity of the network, curtailing losses and the amount of reactive energy to be provided. (orig.)

  5. Reduced Voltage Scaling in Clock Distribution Networks

    Directory of Open Access Journals (Sweden)

    Khader Mohammad

    2009-01-01

    Full Text Available We propose a novel circuit technique to generate a reduced voltage swing (RVS signals for active power reduction on main buses and clocks. This is achieved without performance degradation, without extra power supply requirement, and with minimum area overhead. The technique stops the discharge path on the net that is swinging low at a certain voltage value. It reduces active power on the target net by as much as 33% compared to traditional full swing signaling. The logic 0 voltage value is programmable through control bits. If desired, the reduced-swing mode can also be disabled. The approach assumes that the logic 0 voltage value is always less than the threshold voltage of the nMOS receivers, which eliminate the need of the low to high voltage translation. The reduced noise margin and the increased leakage on the receiver transistors using this approach have been addressed through the selective usage of multithreshold voltage (MTV devices and the programmability of the low voltage value.

  6. Portable High Voltage Impulse Generator

    Directory of Open Access Journals (Sweden)

    S. Gómez

    2011-06-01

    Full Text Available This paper presents a portable high voltage impulse generator which was designed and built with insulation up to 20 kV. This design was based on previous work in which simulation software for standard waves was developed. Commercial components and low-cost components were used in this work; however, these particular elements are not generally used for high voltage applications. The impulse generators used in industry and laboratories are usually expensive; they are built to withstand extra high voltage and they are big, making them impossible to transport. The proposed generator is portable, thereby allowing tests to be made on devices that cannot be moved from their location. The results obtained with the proposed impulse generator were satisfactory in terms of time and waveforms compared to other commercial impulse generators and the standard impulse wave simulator.

  7. Network-Cognizant Voltage Droop Control for Distribution Grids

    Energy Technology Data Exchange (ETDEWEB)

    Baker, Kyri; Bernstein, Andrey; Dall' Anese, Emiliano; Zhao, Changhong

    2017-01-01

    This paper examines distribution systems with a high integration of distributed energy resources (DERs) and addresses the design of local control methods for real-time voltage regulation. Particularly, the paper focuses on proportional control strategies where the active and reactive output-powers of DERs are adjusted in response to (and proportionally to) local changes in voltage levels. The design of the voltage-active power and voltage-reactive power characteristics leverages suitable linear approximation of the AC power-flow equations and is network-cognizant; that is, the coefficients of the controllers embed information on the location of the DERs and forecasted non-controllable loads/injections and, consequently, on the effect of DER power adjustments on the overall voltage profile. A robust approach is pursued to cope with uncertainty in the forecasted non-controllable loads/power injections. Stability of the proposed local controllers is analytically assessed and numerically corroborated.

  8. High-voltage test and measuring techniques

    CERN Document Server

    Hauschild, Wolfgang

    2014-01-01

    It is the intent of this book to combine high-voltage (HV) engineering with HV testing technique and HV measuring technique. Based on long-term experience gained by the authors as lecturer and researcher as well as member in international organizations, such as IEC and CIGRE, the book will reflect the state of the art as well as the future trends in testing and diagnostics of HV equipment to ensure a reliable generation, transmission and distribution of electrical energy. The book is intended not only for experts but also for students in electrical engineering and high-voltage engineering.

  9. Voltage Sags Matching to Locate Faults for Underground Distribution Networks

    Directory of Open Access Journals (Sweden)

    BAKAR, A. H. A.

    2011-05-01

    Full Text Available A voltage sags matching to locate a fault for underground distribution network is presented in this paper. Firstly the method identifies the faulted section by matching a voltage sags measured at the primary substation during a fault with pre-developed voltage sag database. From the identified faulted section, the distance of a fault from sending-end is calculated. The problem of multiple sections is addressed by ranking approach. Test results on an underground distribution network shows most faults can be located by the first attempt within high accuracy distance. Only few faulted sections found by the second attempt. Since the method is using only voltage sag data, monitored at the primary substation, the method is considers economical to be implemented for a rural distribution network.

  10. High-Voltage Droplet Dispenser

    Science.gov (United States)

    Eichenberg, Dennis J.

    2003-01-01

    An apparatus that is extremely effective in dispensing a wide range of droplets has been developed. This droplet dispenser is unique in that it utilizes a droplet bias voltage, as well as an ionization pulse, to release a droplet. Apparatuses that deploy individual droplets have been used in many applications, including, notably, study of combustion of liquid fuels. Experiments on isolated droplets are useful in that they enable the study of droplet phenomena under well-controlled and simplified conditions. In this apparatus, a syringe dispenses a known value of liquid, which emerges from, and hangs onto, the outer end of a flat-tipped, stainless steel needle. Somewhat below the needle tip and droplet is a ring electrode. A bias high voltage, followed by a high-voltage pulse, is applied so as to attract the droplet sufficiently to pull it off the needle. The voltages are such that the droplet and needle are negatively charged and the ring electrode is positively charged.

  11. TRANSISTOR HIGH VOLTAGE POWER SUPPLY

    Science.gov (United States)

    Driver, G.E.

    1958-07-15

    High voltage, direct current power supplies are described for use with battery powered nuclear detection equipment. The particular advantages of the power supply described, are increased efficiency and reduced size and welght brought about by the use of transistors in the circuit. An important feature resides tn the employment of a pair of transistors in an alternatefiring oscillator circuit having a coupling transformer and other circuit components which are used for interconnecting the various electrodes of the transistors.

  12. Advances in high voltage engineering

    CERN Document Server

    Haddad, A

    2005-01-01

    This book addresses the very latest research and development issues in high voltage technology and is intended as a reference source for researchers and students in the field, specifically covering developments throughout the past decade. This unique blend of expert authors and comprehensive subject coverage means that this book is ideally suited as a reference source for engineers and academics in the field for years to come.

  13. Energy Storage Options for Voltage Support in Low-Voltage Grids with High Penetration of Photovoltaic

    DEFF Research Database (Denmark)

    Marra, Francesco; Tarek Fawzy, Y.; Bülo, Thorsten

    2012-01-01

    The generation of power by photovoltaic (PV) systems is constantly increasing in low-voltage (LV) distribution grids, in line with the European environmental targets. To cope with the effects on grid voltage profiles during high generation and low demand periods, new solutions need to be establis......The generation of power by photovoltaic (PV) systems is constantly increasing in low-voltage (LV) distribution grids, in line with the European environmental targets. To cope with the effects on grid voltage profiles during high generation and low demand periods, new solutions need...... to be established. In the long term, these solutions should also aim to allow further more PV installed capacity, while meeting the power quality requirements. In this paper, different concepts of energy storage are proposed to ensure the voltage quality requirements in a LV grid with high PV penetration...

  14. Distribution of high-voltage-activated calcium channels in cultured gamma-aminobutyric acidergic neurons from mouse cerebral cortex.

    Science.gov (United States)

    Timmermann, Daniel B; Westenbroek, Ruth E; Schousboe, Arne; Catterall, William A

    2002-01-01

    The localization of voltage-gated calcium channel (VGCC) alpha(1) subunits in cultured GABAergic mouse cortical neurons was examined by immunocytochemical methods. Ca(v)1.2 and Ca(v)1.3 subunits of L-type VGCCs were found in cell bodies and dendrites of GABA-immunopositive neurons. Likewise, the Ca(v)2.3 subunit of R-type VGCCs was expressed in a somatodendritic pattern. Ca(v)2.2 subunits of N-type channels were found exclusively in small varicosities that were identified as presynaptic nerve terminals based on their expression of synaptic marker proteins. Two splice variants of the Ca(v)2.1 subunit of P/Q-type VGCCs showed widely differing expression patterns. The rbA isoform displayed a purely somatodendritic staining pattern, whereas the BI isoform was confined to axon-like fibers and nerve terminals. The nerve terminals of these cultured GABAergic neurons express Ca(v)2.2 either alone or in combination with Ca(v)2.1 (BI isoform) but never express Ca(v)2.1 alone. The functional association between VGCCs and the neurotransmitter release machinery was probed using the FM1-43 dye-labeling technique. N-type VGCCs were found to be tightly coupled to exocytosis in these cultured cortical neurons, and P-type VGCCs were also important in a fraction of the cells. The predominant role of N-type VGCCs in neurotransmitter release and the specific localization of the BI isoform of Ca(v)2.1 in the nerve terminals of these neurons distinguish them from previously studied central neurons. The complementary localization patterns observed for two different isoforms of the Ca(v)2.1 subunits provide direct evidence for alternative splicing as a means of generating functional diversity among neuronal calcium channels. Copyright 2002 Wiley-Liss, Inc.

  15. 30 CFR 75.810 - High-voltage trailing cables; splices.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage trailing cables; splices. 75.810... SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution § 75.810 High-voltage trailing cables; splices. In the case of high-voltage cables used as trailing...

  16. 30 CFR 77.807-1 - High-voltage powerlines; clearances above ground.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage powerlines; clearances above... OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.807-1 High-voltage powerlines; clearances above ground. High-voltage powerlines located above driveways, haulageways, and railroad tracks...

  17. 30 CFR 75.800 - High-voltage circuits; circuit breakers.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage circuits; circuit breakers. 75.800... SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution § 75.800 High-voltage circuits; circuit breakers. High-voltage circuits entering the underground area...

  18. 30 CFR 75.812-2 - High-voltage power centers and transformers; record of examination.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage power centers and transformers... High-Voltage Distribution § 75.812-2 High-voltage power centers and transformers; record of examination... record shall be kept in a book approved by the Secretary. High-Voltage Longwalls Source: 67 FR 11001, Mar...

  19. 30 CFR 77.800 - High-voltage circuits; circuit breakers.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage circuits; circuit breakers. 77.800... COAL MINES Surface High-Voltage Distribution § 77.800 High-voltage circuits; circuit breakers. High-voltage circuits supplying power to portable or mobile equipment shall be protected by suitable circuit...

  20. 30 CFR 77.804 - High-voltage trailing cables; minimum design requirements.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage trailing cables; minimum design... OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.804 High-voltage trailing cables; minimum design requirements. (a) High-voltage trailing cables used in resistance grounded systems shall be...

  1. Advanced High Voltage Power Device Concepts

    CERN Document Server

    Baliga, B Jayant

    2012-01-01

    Advanced High Voltage Power Device Concepts describes devices utilized in power transmission and distribution equipment, and for very high power motor control in electric trains and steel-mills. Since these devices must be capable of supporting more than 5000-volts in the blocking mode, this books covers operation of devices rated at 5,000-V, 10,000-V and 20,000-V. Advanced concepts (the MCT, the BRT, and the EST) that enable MOS-gated control of power thyristor structures are described and analyzed in detail. In addition, detailed analyses of the silicon IGBT, as well as the silicon carbide MOSFET and IGBT, are provided for comparison purposes. Throughout the book, analytical models are generated to give a better understanding of the physics of operation for all the structures. This book provides readers with: The first comprehensive treatment of high voltage (over 5000-volts) power devices suitable for the power distribution, traction, and motor-control markets;  Analytical formulations for all the device ...

  2. High voltage MOSFET switching circuit

    Science.gov (United States)

    McEwan, Thomas E.

    1994-01-01

    The problem of source lead inductance in a MOSFET switching circuit is compensated for by adding an inductor to the gate circuit. The gate circuit inductor produces an inductive spike which counters the source lead inductive drop to produce a rectangular drive voltage waveform at the internal gate-source terminals of the MOSFET.

  3. High-voltage power supply unit

    CERN Document Server

    Garipov, G K; Silaev, A A; Shirokov, A V

    2002-01-01

    A unit comprising four high-voltage power sources (HPS) is designed for power supply of four independent photomultipliers. Each HPS comprises a pulse-width modulator, digital-to-analog converter, base voltage source and digital interface. HPS unit supplies up to 2000 V output voltage, up to 2.5 mA current and long-term stability equal to +- 0.03%

  4. Voltage Control in Distribution Systems Considered Reactive Power Output Sharing

    Science.gov (United States)

    Oshiro, Masato; Senjyu, Tomonobu; Yona, Atsushi; Urasaki, Naomitsu; Funabashi, Toshihisa

    In recent years, distributed generation (DG) and renewable energy source (RES) are attracting special attention to distribution systems. Renewable energy such as photovoltaic (PV) system and wind turbine generator are used as a source of clean energy. However, the large amount of distributed generation causes voltage deviation beyond a statutory range in distribution systems. This paper proposes a methodology for voltage control by using inverters interfaced with DG and tap changing transformers. In the proposed method a one-day schedule of voltage references for the control devices are determined by an optimization technique based on predicted values of load demand and PV power generation. Furthermore, decided reactive power output according to the locally measurable voltage based on droop characteristic. Slope and base value on droop characteristic are selected by fuzzy control. The proposed method accomplishes improvement against voltage distribution considered the reactive power output sharing and reduction of distribution loss. The effectiveness of the proposed method is verified by using MATLAB®.

  5. Small Distributed Renewable Energy Generation for Low Voltage Distribution Networks

    Directory of Open Access Journals (Sweden)

    Chindris M.

    2016-08-01

    Full Text Available Driven by the existing energy policies, the use of renewable energy has increased considerably all over the world in order to respond to the increasing energy consumption and to reduce the environmental impact of the electricity generation. Although most policy makers and companies are focusing on large applications, the use of cheap small generation units, based on local renewable resources, has become increasingly attractive for the general public, small farms and remote communities. The paper presents several results of a research project aiming to identify the power quality issues and the impact of RES based distributed generation (DG or other non-linear loads on low voltage (LV distribution networks in Romania; the final goal is to develop a Universal Power Quality Conditioner (UPQC able to diminish the existing disturbances. Basically, the work analyses the existing DG technologies and identifies possible solutions for their integration in Romania; taking into account the existent state of the art, the attention was paid on small systems, using wind and solar energy, and on possibility to integrate them into suburban and rural LV distribution networks. The presence of DG units at distribution voltage level means the transition from traditional passive to active distribution networks. In general, the relatively low penetration levels of DG does not produce problems; however, the nowadays massive increase of local power generation have led to new integration challenges in order to ensure the reliability and quality of the power supply. Power quality issues are identified and their assessment is the key element in the design of measures aiming to diminish all existing disturbances.

  6. Enhancement of AC high voltage measurements’ uncertainty using a high voltage divider calibration method

    Directory of Open Access Journals (Sweden)

    El-Rifaie Ali M.

    2015-01-01

    Full Text Available This paper discusses enhancing of the measurements’ uncertainty for AC high voltage up to 100 kV. This is achieved by using a high voltage divider calibration method. Voltage measurements have been carried out at the Egyptian national institute for standards (NIS, using a high voltage measuring system (Phenix-KVM100, that consists of a high voltage divider and a voltage display. The voltage divider and display have been calibrated in low and high voltage ranges. Reference standard digital voltmeter and a multifunction calibrator have been used to calibrate the KVM100 for achieving accurate and traceable results. All calibrations have been performed automatically using Laboratory Virtual Instrument Engineering Workbench (LabVIEW programs specially designed for this task. Uncertainty budget has been evaluated to get the measurements’ expanded uncertainties.

  7. Compact, Lightweight, High Voltage Propellant Isolators Project

    Data.gov (United States)

    National Aeronautics and Space Administration — TA&T, Inc. proposes an enabling fabrication process for high voltage isolators required in high power solar electric and nuclear electric propulsion (SEP and...

  8. High voltage electricity installations a planning perspective

    CERN Document Server

    Jay, Stephen Andrew

    2006-01-01

    The presence of high voltage power lines has provoked widespread concern for many years. High Voltage Electricity Installations presents an in-depth study of policy surrounding the planning of high voltage installations, discussing the manner in which they are percieved by the public, and the associated environmental issues. An analysis of these concerns, along with the geographical, environmental and political influences that shape their expression, is presented. Investigates local planning policy in an area of the energy sector that is of highly topical environmental and public concern Cover

  9. Integration of 100% Micro-Distributed Energy Resources in the Low Voltage Distribution Network

    DEFF Research Database (Denmark)

    You, Shi; Segerberg, Helena

    2014-01-01

    The existing electricity infrastructure may to a great extent limit a high penetration of the micro-sized Distributed Energy Resources (DERs), due to the physical bottlenecks, e.g. thermal capacitates of cables, transformers and the voltage limitations. In this study, the integration impacts...... of heat pumps (HPs) and plug-in electric vehicles (PEVs) at 100% penetration level on a representative urban residential low voltage (LV) distribution network of Denmark are investigated by performing a steady-state load flow analysis through an integrated simulation setup. Three DERs integration...

  10. Protection of Low Voltage CIGRE distribution Network

    DEFF Research Database (Denmark)

    Mustafa, Ghullam; Bak-Jensen, Birgitte; Bak, Claus Leth

    2013-01-01

    the inverters used for Photovoltaic (PV) and battery applications. The disconnection of the PV solar panels when in island mode is made by proposing switch dis-connecting devices. ABB is currently using these kinds of disconnection devices for the purpose of protecting solar panels against over voltages...

  11. High voltage and electrical insulation engineering

    CERN Document Server

    Arora, Ravindra

    2011-01-01

    "The book is written for students as well as for teachers and researchers in the field of High Voltage and Insulation Engineering. It is based on the advance level courses conducted at TU Dresden, Germany and Indian Institute of Technology Kanpur, India. The book has a novel approach describing the fundamental concept of field dependent behavior of dielectrics subjected to high voltage. There is no other book in the field of high voltage engineering following this new approach in describing the behavior of dielectrics. The contents begin with the description of fundamental terminology in the subject of high voltage engineering. It is followed by the classification of electric fields and the techniques of field estimation. Performance of gaseous, liquid and solid dielectrics under different field conditions is described in the subsequent chapters. Separate chapters on vacuum as insulation and the lightning phenomenon are included"--

  12. Impact of Voltage Conditions on Distributed Generation Connectivity in Medium Voltage Grids

    OpenAIRE

    Ireneusz Grządzielski; Krzysztof Marszałkiewicz; Andrzej Trzeciak

    2015-01-01

    A significant increase in the distributed generating sources connected and planned for connection to medium voltage (MV) grids makes voltage criteria very important in assessing the sources’ connectivity. Many requests have been submitted for connection of distributed generation sources at a considerable distance (even a dozen or so kilometres) from a main supply substation’s MV buses. As a rule, these are requests for the interconnection deep in an existing MV bus, but also directly to MV sw...

  13. Methods and Strategies for Overvoltage Prevention in Low Voltage Distribution Systems with PV

    DEFF Research Database (Denmark)

    Hashemi Toghroljerdi, Seyedmostafa; Østergaard, Jacob

    2016-01-01

    absorption by PV inverters, application of active medium voltage to low voltage (MV/LV) transformers, active power curtailment, and demand response (DR). Coordination between voltage control units by localized, distributed, and centralized voltage control methods is compared using the voltage sensitivity...... to handle a high share of PV power. This paper provides an in-depth review of methods and strategies proposed to prevent overvoltage in LV grids with PV, and discusses the effectiveness, advantages, and disadvantages of them in detail. Based on the mathematical framework presented in the paper...

  14. Impact of Voltage Conditions on Distributed Generation Connectivity in Medium Voltage Grids

    Directory of Open Access Journals (Sweden)

    Ireneusz Grządzielski

    2015-12-01

    Full Text Available A significant increase in the distributed generating sources connected and planned for connection to medium voltage (MV grids makes voltage criteria very important in assessing the sources’ connectivity. Many requests have been submitted for connection of distributed generation sources at a considerable distance (even a dozen or so kilometres from a main supply substation’s MV buses. As a rule, these are requests for the interconnection deep in an existing MV bus, but also directly to MV switching substation bays. Then maintaining appropriate voltage levels becomes a basic technical problem. Another technical problem relates to meeting the power quality criteria. THD index, and the level of individual harmonics, significantly increases, in many cases reaching or even exceeding the boundary values. With their extensive experience, the authors present examples and results of some analyses herewith. They indicate the impact of voltage conditions on the connection possibilities of distributed generation to MV grids.

  15. Experimental investigation of SDBD plasma actuator driven by AC high voltage with a superimposed positive pulse bias voltage

    Science.gov (United States)

    Qi, Xiao-Hua; Yan, Hui-Jie; Yang, Liang; Hua, Yue; Ren, Chun-Sheng

    2017-08-01

    In this work, a driven voltage consisting of AC high voltage with a superimposed positive pulse bias voltage ("AC+ Positive pulse bias" voltage) is adopted to study the performance of a surface dielectric barrier discharge plasma actuator under atmospheric conditions. To compare the performance of the actuator driven by single-AC voltage and "AC+ Positive pulse bias" voltage, the actuator-induced thrust force and power consumption are measured as a function of the applied AC voltage, and the measured results indicate that the thrust force can be promoted significantly after superimposing the positive pulse bias voltage. The physical mechanism behind the thrust force changes is analyzed by measuring the optical properties, electrical characteristics, and surface potential distribution. Experimental results indicate that the glow-like discharge in the AC voltage half-cycle, next to the cycle where a bias voltage pulse has been applied, is enhanced after applying the positive pulse bias voltage, and this perhaps is the main reason for the thrust force increase. Moreover, surface potential measurement results reveal that the spatial electric field formed by the surface charge accumulation after positive pulse discharge can significantly affect the applied external electric field, and this perhaps can be responsible for the experimental phenomenon that the decrease of thrust force is delayed by pulse bias voltage action after the filament discharge occurs in the glow-like discharge region. The schlieren images further verify that the actuator-induced airflow velocity increases with the positive pulse voltage.

  16. Feasibility of high-speed power line carrier system to Japanese overhead low voltage distribution lines; Teiatsu haidensen hanso no kosokuka no kanosei (hanso sningo denpa purogram no kanosei)

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, T.; Takeshita, K.; Ishino, R.

    2000-06-01

    The high-speed distribution line carrier systems on underground distribution lines are being developed in Germany. To estimate these systems on Japanese overhead low voltage distribution lines, the Carrier Propagation Program has been developed and applicability of OFDM system was roughly estimated. 1. Carrier Propagation Program Carrier Propagation Program that calculates the carrier propagation characteristics of any line structure was developed. 2. Carrier propagation characteristics Carrier propagation characteristics on typical Japanese overhead low voltage distribution lines were calculated 3.Rough estimation of OFDM system Electric fields caused by carrier at near point were calculated on the basis on carrier propagation characteristics. Results of rough estimation are as follows: - Electric field caused by carrier of more than 2Mbps system exceeds the value of the regulation. (author)

  17. Feeder Voltage Regulation with High-Penetration PV Using Advanced Inverters and a Distribution Management System: A Duke Energy Case Study

    Energy Technology Data Exchange (ETDEWEB)

    Palmintier, Bryan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Giraldez, Julieta [National Renewable Energy Lab. (NREL), Golden, CO (United States); Gruchalla, Kenny [National Renewable Energy Lab. (NREL), Golden, CO (United States); Gotseff, Peter [National Renewable Energy Lab. (NREL), Golden, CO (United States); Nagarajan, Adarsh [National Renewable Energy Lab. (NREL), Golden, CO (United States); Harris, Tom [National Renewable Energy Lab. (NREL), Golden, CO (United States); Bugbee, Bruce [National Renewable Energy Lab. (NREL), Golden, CO (United States); Baggu, Murali [National Renewable Energy Lab. (NREL), Golden, CO (United States); Gantz, Jesse [GE Grid Solutions, Fairfield, CT (United States); Boardman, Ethan [GE Grid Solutions, Fairfield, CT (United States)

    2016-11-01

    Duke Energy, Alstom Grid, and the National Renewable Energy Laboratory teamed up to better understand the impacts of solar photovoltaics (PV) on distribution system operations. The core goal of the project is to compare the operational - specifically, voltage regulation - impacts of three classes of PV inverter operations: 1.) Active power only (Baseline); 2.) Local inverter control (e.g., PF...not equal...1, Q(V), etc.); and 3.) Integrated volt-VAR control (centralized through the distribution management system). These comparisons were made using multiple approaches, each of which represents an important research-and-development effort on its own: a) Quasi-steady-state time-series modeling for approximately 1 year of operations using the Alstom eTerra (DOTS) system as a simulation engine, augmented by Python scripting for scenario and time-series control and using external models for an advanced inverter; b) Power-hardware-in-the-loop (PHIL) testing of a 500-kVA-class advanced inverter and traditional voltage regulating equipment. This PHIL testing used cosimulation to link full-scale feeder simulation using DOTS in real time to hardware testing; c) Advanced visualization to provide improved insights into time-series results and other PV operational impacts; and d) Cost-benefit analysis to compare the financial and business-model impacts of each integration approach.

  18. Power Capability in Low Voltage DC Distribution Systems

    Directory of Open Access Journals (Sweden)

    C.O. Gecan

    2009-12-01

    Full Text Available Recent developments in power electronics components enable the use of power electronics in Low Voltage (LV networks. This development makes the model of a Low Voltage Direct Current (LVDC distribution system possible. The technical and economical benefits of this technology make possible the alternative hypothesis of using DC instead of AC distribution systems. Some aspects, such as increasing the capability of the existing lines, interconnecting distributed generation units and even supplying in DC some loads are creating additional requirements of using a LVDC distribution system. The paper presents some general considerations regarding cables used in a LVAC distribution system and different line reconfigurations witch enable the use of cobles in a LVDC distribution system. The reconfigurations are presented in respect of the DC network topologies: unipolar and bipolar. The central aim of this paper is to investigate capability of power transmission and to calculate the transmission distance for cables used in Low Voltage AC and DC distribution systems. Capability computation is considered in respect of two constrains imposed in the cables cross section selection: cable thermal limit and the maximum allowable voltage drop. Cable thermal limit is represented in calculations by the maximum rated current. The equations used to calculate the power capability are presented for single-phase and threephase AC networks and unipolar and bipolar DC networks. Based on these equations, comparisons between power capability of cables with different cross sections used in Low Voltage DC and AC distribution systems are realized and presented.

  19. High voltage testing for the Majorana Demonstrator

    Energy Technology Data Exchange (ETDEWEB)

    Abgrall, N.; Arnquist, Isaac J.; Avignone, F. T.; Barabash, A.; Bertrand, F.; Bradley, A. W.; Brudanin, V.; Busch, Matthew; Buuck, M.; Byram, D.; Caldwell, A. S.; Chan, Yuen-Dat; Christofferson, C. D.; Chu, Pamela M.; Cuesta, C.; Detwiler, Jason A.; Doe, P. J.; Dunagan, C.; Efremenko, Yuri; Ejiri, H.; Elliott, S. R.; Fu, Z.; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guinn, I.; Guiseppe, V. E.; Henning, R.; Hoppe, Eric W.; Howard, S.; Howe, M. A.; Jasinski, B. R.; Keeter, K.; Kidd, M. F.; Konovalov, S.; Kouzes, Richard T.; Laferriere, Brian D.; Leon, Jonathan D.; Li, Alexander D.; MacMullin, J.; Martin, R. D.; Massarcyk, R.; Meijer, S. J.; Mertens, S.; Orrell, John L.; O' Shaughnessy, C.; Poon, Alan W.; Radford, D. C.; Rager, J.; Rielage, Keith; Robertson, R. G. H.; Romero Romo, M.; Shanks, B.; Shirchenko, M.; Snyder, N.; Suriano, Anne-Marie E.; Tedeschi, D.; Thompson, Andrew; Ton, K. T.; Trimble, J. E.; Varner, R. L.; Vasilyev, Sergey; Vetter, Kai; Vorren, Kris R.; White, Brandon R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Yu, Chang-Hong; Yumatov, V.

    2016-07-01

    The Majorana Collaboration is constructing theMajorana Demonstrator, an ultra-low background, 44-kg modular high-purity Ge (HPGe) detector array to search for neutrinoless double-beta decay in 76Ge. The phenomenon of surface micro-discharge induced by high-voltage has been studied in the context of theMajorana Demonstrator. This effect can damage the front-end electronics or mimic detector signals. To ensure the correct performance, every high-voltage cable and feedthrough must be capable of supplying HPGe detector operating voltages as high as 5 kV without exhibiting discharge. R&D measurements were carried out to understand the testing system and determine the optimum design configuration of the high-voltage path, including different improvements of the cable layout and feedthrough flange model selection. Every cable and feedthrough to be used at the Majorana Demonstrator was characterized and the micro-discharge effects during theMajorana Demonstrator commissioning phase were studied. A stable configuration has been achieved, and the cables and connectors can supply HPGe detector operating voltages without exhibiting discharge.

  20. 30 CFR 75.811 - High-voltage underground equipment; grounding.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage underground equipment; grounding... COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution § 75.811 High-voltage underground equipment; grounding. Frames, supporting structures and...

  1. 30 CFR 77.807-3 - Movement of equipment; minimum distance from high-voltage lines.

    Science.gov (United States)

    2010-07-01

    ... high-voltage lines. 77.807-3 Section 77.807-3 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... WORK AREAS OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.807-3 Movement of equipment; minimum distance from high-voltage lines. When any part of any equipment operated on the surface of any...

  2. Development of an Analysis System for Low Voltage Distribution System

    Science.gov (United States)

    Matsuda, Katsuhiro; Wada, Masaru; Hirano, Shinichiro; Hirai, Yoshihiro; Tsuboe, Yasuhiro; Watanabe, Masahiro; Furukawa, Toshiyuki

    In recent years, distributed resources such as photovoltaic power generation system or wind-turbine generator system are increased, therefore the distributed resources which connect to distribution networks are increased gradually. Under the situation there are several problems such as expansion of the voltage fluctuation, increase of the short circuit current, increase of harmonics phenomenon which we have to consider, and the problems make us difficult to examine the effect of interconnection and to design the distribution system. However, analysis support system to evaluate the influence to connect distributed resources to low voltage distribution system has not developed. Therefore We have developed the analysis system for low voltage for low voltage distribution systems. We can evaluate the influence of distributed resources accurately, examine the interconnection and design the configuration of distribution networks by using the analysis system. In this paper, the concept of the analysis system, the load flow method for unbalanced V-connection 3-phase 4-line distribution system and the calculation method for the connectable capacity of distributed resources. Outline of the man/machine interface and examples of calculation results for sample network are also described.

  3. 76 FR 70721 - Voltage Coordination on High Voltage Grids; Notice of Staff Workshop

    Science.gov (United States)

    2011-11-15

    ... Energy Regulatory Commission Voltage Coordination on High Voltage Grids; Notice of Staff Workshop Take notice that the Federal Energy Regulatory Commission will hold a Workshop on Voltage Coordination on High Voltage Grids on Thursday, December 1, 2011 from 9 a.m. to 4:30 p.m. This staff-led workshop will be held...

  4. High Efficiency Power Converter for Low Voltage High Power Applications

    DEFF Research Database (Denmark)

    Nymand, Morten

    . A detailed analysis of dominant loss factors in high power converters for low voltage applications is presented. The analysis concludes that: • Power transformers for low voltage high power, if properly designed, will have extremely low leakage inductance. • If optimally designed, boost converters......The topic of this thesis is the design of high efficiency power electronic dc-to-dc converters for high-power, low-input-voltage to high-output-voltage applications. These converters are increasingly required for emerging sustainable energy systems such as fuel cell, battery or photo voltaic based......, if a converter is properly designed, primary side voltage clamp circuits will not even work in low voltage high power converters. • Very high conversion efficiency can be achieved. Peak efficiency of 98% and worst case minimum efficiency of 96.8% are demonstrated on a 1.5 kW converter. The ability...

  5. High Efficiency Power Converter for Low Voltage High Power Applications

    DEFF Research Database (Denmark)

    Nymand, Morten

    and maximum output power. In chapter 3, a detailed analysis of dominant loss factors in high power converters for low voltage applications is presented. The analysis concludes that: • Power transformers for low voltage high power, if properly designed, will have extremely low leakage inductance......The topic of this thesis is the design of high efficiency power electronic dc-to-dc converters for high-power, low-input-voltage to high-output-voltage applications. These converters are increasingly required for emerging sustainable energy systems such as fuel cell, battery or photo voltaic based....... • If optimally designed, boost converters will be much more efficient than comparable buck type converters for high power low voltage applications. • The use of voltage clamp circuits to protect primary switches in boost converters is no longer needed for device protection. On the other hand...

  6. Pulsed high voltage discharge induce hematologic changes

    African Journals Online (AJOL)

    STORAGESEVER

    2009-10-19

    Oct 19, 2009 ... The aim of this work to examine the effect of the gas-liquid hybrid discharge treatment system on some hematological ... liquid phase. The high energy plasma arc produces a pressure shock wave, electromagnetic radiations, .... through a 50 kilo-ohm resistor by a negative dc high-voltage power supply and ...

  7. Distributed Control to Ensure Proportional Load Sharing and Improve Voltage Regulation in Low-Voltage DC Microgrids

    DEFF Research Database (Denmark)

    Anand, Sandeep; G. Fernandes, Baylon; Guerrero, Josep M.

    2013-01-01

    of the system. Conventional droop controllers are not effective in achieving both the aforementioned objectives simultaneously. Reasons for this are identified to be the error in nominal voltages and load distribution. Though centralized controller achieves these objectives, it requires high-speed communication......DC microgrids are gaining popularity due to high efficiency, high reliability, and easy interconnection of renewable sources as compared to the ac system. Control objectives of dc microgrid are: 1) to ensure equal load sharing (in per unit) among sources; and 2) to maintain low-voltage regulation...... and offers less reliability due to single point of failure. To address these limitations, this paper proposes a new decentralized controller for dc microgrid. Key advantages are high reliability, low-voltage regulation, and equal load sharing, utilizing low-bandwidth communication. To evaluate the dynamic...

  8. Optically triggered high voltage switch network and method for switching a high voltage

    Science.gov (United States)

    El-Sharkawi, Mohamed A.; Andexler, George; Silberkleit, Lee I.

    1993-01-19

    An optically triggered solid state switch and method for switching a high voltage electrical current. A plurality of solid state switches (350) are connected in series for controlling electrical current flow between a compensation capacitor (112) and ground in a reactive power compensator (50, 50') that monitors the voltage and current flowing through each of three distribution lines (52a, 52b and 52c), which are supplying three-phase power to one or more inductive loads. An optical transmitter (100) controlled by the reactive power compensation system produces light pulses that are conveyed over optical fibers (102) to a switch driver (110') that includes a plurality of series connected optical triger circuits (288). Each of the optical trigger circuits controls a pair of the solid state switches and includes a plurality of series connected resistors (294, 326, 330, and 334) that equalize or balance the potential across the plurality of trigger circuits. The trigger circuits are connected to one of the distribution lines through a trigger capacitor (340). In each switch driver, the light signals activate a phototransistor (300) so that an electrical current flows from one of the energy reservoir capacitors through a pulse transformer (306) in the trigger circuit, producing gate signals that turn on the pair of serially connected solid state switches (350).

  9. 76 FR 72203 - Voltage Coordination on High Voltage Grids; Notice of Reliability Workshop Agenda

    Science.gov (United States)

    2011-11-22

    ... Energy Regulatory Commission Voltage Coordination on High Voltage Grids; Notice of Reliability Workshop... between voltage control, reliability, and economic dispatch. In addition, the Commission will consider how improvements to dispatch and voltage control software could improve reliability and market efficiency. This...

  10. Resonance analysis in parallel voltage-controlled Distributed Generation inverters

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Blaabjerg, Frede; Chen, Zhe

    2013-01-01

    of the inverters and the remaining system dynamics. This paper addresses the later interactions and the consequent resonances through the frequency-domain analysis of the inverters output impedances and the remaining equivalent network impedance. Furthermore, impacts of the virtual output impedance loop......Thanks to the fast responses of the inner voltage and current control loops, the dynamic behaviors of parallel voltage-controlled Distributed Generation (DG) inverters not only relies on the stability of load sharing among them, but subjects to the interactions between the voltage control loops...

  11. 30 CFR 77.807-2 - Booms and masts; minimum distance from high-voltage lines.

    Science.gov (United States)

    2010-07-01

    ...-voltage lines. 77.807-2 Section 77.807-2 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... WORK AREAS OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.807-2 Booms and masts; minimum distance from high-voltage lines. The booms and masts of equipment operated on the surface of any...

  12. Voltage regulator placement in radial distribution system using plant ...

    African Journals Online (AJOL)

    Voltage regulator placement in radial distribution system using plant growth simulation algorithm. ... The effectiveness of the proposed method is illustrated with 33 bus and 69 bus radial distribution systems and these results are compared with Discrete Particle Swarm Optimization method. International Journal of ...

  13. Modular high voltage power supply for chemical analysis

    Science.gov (United States)

    Stamps, James F [Livermore, CA; Yee, Daniel D [Dublin, CA

    2008-07-15

    A high voltage power supply for use in a system such as a microfluidics system, uses a DC-DC converter in parallel with a voltage-controlled resistor. A feedback circuit provides a control signal for the DC-DC converter and voltage-controlled resistor so as to regulate the output voltage of the high voltage power supply, as well as, to sink or source current from the high voltage supply.

  14. An Inexpensive Source of High Voltage

    Science.gov (United States)

    Saraiva, Carlos

    2012-01-01

    As a physics teacher I like recycling old apparatus and using them for demonstrations in my classes. In physics laboratories in schools, sources of high voltage include induction coils or electronic systems that can be bought from companies that sell lab equipment. But these sources can be very expensive. In this article, I will explain how you…

  15. Recycling potential for low voltage and high voltage high rupturing capacity fuse links.

    Science.gov (United States)

    Psomopoulos, Constantinos S; Barkas, Dimitrios A; Kaminaris, Stavros D; Ioannidis, George C; Karagiannopoulos, Panagiotis

    2017-12-01

    Low voltage and high voltage high-rupturing-capacity fuse links are used in LV and HV installations respectively, protecting mainly the LV and HV electricity distribution and transportation networks. The Waste Electrical and Electronic Equipment Directive (2002/96/EC) for "Waste of electrical and electronic equipment" is the main related legislation and as it concerns electrical and electronic equipment, it includes electric fuses. Although, the fuse links consist of recyclable materials, only small scale actions have been implemented for their recycling around Europe. This work presents the possibilities for material recovery from this specialized industrial waste for which there are only limited volume data. Furthermore, in order to present the huge possibilities and environmental benefits, it presents the potential for recycling of HRC fuses used by the Public Power Corporation of Greece, which is the major consumer for the country, but one of the smallest ones in Europe and globally, emphasizing in this way in the issue. According to the obtained results, fuse recycling could contribute to the effort for minimize the impacts on the environment through materials recovery and reduction of the wastes' volume disposed of in landfills. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Voltage Impacts of Utility-Scale Distributed Wind

    Energy Technology Data Exchange (ETDEWEB)

    Allen, A.

    2014-09-01

    Although most utility-scale wind turbines in the United States are added at the transmission level in large wind power plants, distributed wind power offers an alternative that could increase the overall wind power penetration without the need for additional transmission. This report examines the distribution feeder-level voltage issues that can arise when adding utility-scale wind turbines to the distribution system. Four of the Pacific Northwest National Laboratory taxonomy feeders were examined in detail to study the voltage issues associated with adding wind turbines at different distances from the sub-station. General rules relating feeder resistance up to the point of turbine interconnection to the expected maximum voltage change levels were developed. Additional analysis examined line and transformer overvoltage conditions.

  17. Optimal operation control of low-voltage grids with a high share of distributed power generation[Dissertation 17063]; Optimierte Betriebsfuehrung von Niederspannungsnetzen mit einem hohen Anteil an dezentraler Erzeugung

    Energy Technology Data Exchange (ETDEWEB)

    Malte, C. T.

    2007-07-01

    The importance of renewable energy sources and combined heat and power generation for electricity production will further increase in the next years, not only in Germany but all over Europe. Beside the conventional more or less centrally organised generation and distribution structure, more and more distributed generation (DG) units of different technologies will come to the forefront. Today's centrally organised electricity supply structure is comparatively stable, relatively simple to control and guarantees a high degree of supply quality. But it requests large investments with a long commitment, is less flexible and can barely use efficiency potentials. Distribution grids (low and medium voltage) are essentially passive; this means that the network management is carried out at the higher voltage levels. As more and more DG units feed in the grid, the distribution grids have to become more 'active'. With a high share of wind power, combined heat and power as well as photovoltaic generation, more duties of grid management have to be carried out at the point of common coupling of DG units. This requests for more communication und new control strategies in the distribution grids. At the same time grids with DG have in the mid-term the potential to reduce the susceptibility for large scale black-outs, because, on one hand, with a high number of smaller and individually controlled DG units the breakdown of one unit does not have a major impact and, on the other hand, with a specific grid management the option exists to build up islanded grids during interruptions on the higher voltage levels and to continue to supply the connected customers. In the European research project 'DISPOWER' 38 institutions from all over Europe dealt these topics. In this context a new kind of energy management system for low voltage grids was developed: 'PoMS'. PoMS is the acronym for 'Power Flow and Power Quality Management System'. Major

  18. APPLICATION OF HIGH VOLTAGE DIVIDERS FOR POWER QUALITY INDICES MEASUREMENT

    Directory of Open Access Journals (Sweden)

    Y. L. Anokhin

    2017-12-01

    Full Text Available Introduction. Determination of power quality indices in high-voltage power grids allows to find the reasons for the deterioration of the power quality. The relevant national and International Standards for power quality contain relevant norms of quality indices and requirements for their accuracy measurement. Problem. The most complicated part in the process of measuring the power quality indices at high voltage is the selection of the corresponding high-voltage scale voltage converters. Therefore, comparing the requirements of IEC 61000-4-30 to high voltage scale voltage converters is an important task. Goal. Analysis of the International Standard IEC 61000-4-30 requirements feasibility for measuring the indices of power quality in high-voltage electrical networks using different types of high-voltage scale voltage converters. Methodology. Comparison of the requirements of IEC 61000-4-30 Standard to high-voltage scale voltage converters, when measuring power quality indices, with the characteristics of high voltage electromagnetic transformers used in Ukraine, and with promising developments of high-voltage converters of other types. Results. It is shown in the study that in order to fulfill some of the requirements for class A of IEC 61000-4-30, the characteristics of electromagnetic voltage transformers should be determined in the substation conditions using mobile calibration high-voltage laboratories. To meet all the requirements for Class A IEC 61000-4-30, it is recommended to use broadband high-voltage dividers of resistive-capacitive type. Originality. In study it is shown firstly that all the requirements of the IEC 61000-4-30 Standard for high-voltage scale voltage converters can be performed on the basis of the use of broadband resistive-capacitive damped voltage dividers. Practical value. Expositions of specific types of resistive-capacitive high-voltage dividers are presented, their parameters are confirmed by the results of state

  19. Method for calculating voltage distribution along lengthy insulator strings

    Energy Technology Data Exchange (ETDEWEB)

    Perelman, L.S.

    1978-01-01

    This computer method is based on the simultaneous solution of a set of equations with potential coefficients for charges of conductors, tower and insulator caps, and a set of equations for the insulator capacitance chain. The effect of various factors on the voltage distribution along strings for 750 and 1150/1500 kV lines is considered.

  20. APF for harmonic voltage resonance suppression in distribution system

    DEFF Research Database (Denmark)

    Sun, Xiaofeng; Zeng, Jian; Chen, Zhe

    2010-01-01

    Traditional active power filter (APF) can prevent harmonic current from injecting into power system, but can not damp harmonic propagation in distribution system whereas voltage detection can do. This paper proposes a compound control method of APF based on detection of load current and harmonic...

  1. an improved voltage regulation of a distribution network using facts

    African Journals Online (AJOL)

    OMEJE CO

    2013-07-02

    Jul 2, 2013 ... trouble free, since the TCR achieves its fundamental frequency steady-state operating point at the .... injected by the generator at bus K. PLK and. QLK represent the active and reactive powers drawn by ..... energy efficiency of the power distribution networks. Figure 10: Comparative plot of the bus voltage ...

  2. Voltage regulator placement in radial distribution system using plant ...

    African Journals Online (AJOL)

    user

    Voltage regulator placement in radial distribution system using plant growth simulation algorithm. P.V.V. Rama Rao1*, S. Sivanaga Raju 2. 1*Department of Electrical & Electronics Engineering, Arjun College of Technology & Science, Hyderabad, INDIA. 2 Department of Electrical & Electronics Engineering, JNTUK College ...

  3. Voltage Estimation in Active Distribution Grids Using Neural Networks

    DEFF Research Database (Denmark)

    Pertl, Michael; Heussen, Kai; Gehrke, Oliver

    2016-01-01

    the observability of distribution systems has to be improved. To increase the situational awareness of the power system operator data driven methods can be employed. These methods benefit from newly available data sources such as smart meters. This paper presents a voltage estimation method based on neural networks...

  4. High-voltage multijunction photovoltaic solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Doroshenko, V.G.; Zaks, M.B.; Kalash' yan, V.A.; Lozovskiy, V.N.; Skokov, Yu.V.; Solodukha, O.I.

    1979-01-01

    The possibility of developing a high-voltage multijunction photovoltaic cell (HMPC) based on a single crystal with multiple vertical p-n junctions formed by heavily doped zones at right angles to the illuminated surface of the instrument is demonstrated. A laboratory technology for producing HMPC based on the zone recrystallization method with a temperature gradient and linear zones is presented. The investigated variant of HMPC was made of n-type silicon with resistivity of 1 ohm.cm in which are formed vertical p/sup +/ type zones doped with aluminum or an aluminum-boron alloy. The performance HMPC (with 11 and 5 vertical p-n junctions) was experimentally investigated in the presence of 400 to 500 ms light pulses from a xenon lamp with a near-solar spectrum and the current-voltage characteristic of the HMPC was found to be then virtually unaffected.

  5. Energy harvesting in high voltage measuring techniques

    Science.gov (United States)

    Żyłka, Pawel; Doliński, Marcin

    2016-02-01

    The paper discusses selected problems related to application of energy harvesting (that is, generating electricity from surplus energy present in the environment) to supply autonomous ultra-low-power measurement systems applicable in high voltage engineering. As a practical example of such implementation a laboratory model of a remote temperature sensor is presented, which is self-powered by heat generated in a current-carrying busbar in HV- switchgear. Presented system exploits a thermoelectric harvester based on a passively cooled Peltier module supplying micro-power low-voltage dc-dc converter driving energy-efficient temperature sensor, microcontroller and a fibre-optic transmitter. Performance of the model in laboratory simulated conditions are presented and discussed.

  6. Voltage Control of Distribution Grids with Multi-Microgrids Using Reactive Power Management

    Directory of Open Access Journals (Sweden)

    WLODARCZYK, P.

    2015-02-01

    Full Text Available Low-voltage Microgrids can be valuable sources of ancillary services for the Distribution System Operators (DSOs. The aim of this paper was to study if and how multi-microgrids can contribute to Voltage Control (VC in medium-voltage distribution grids by means of reactive power generation and/or absorption. The hierarchical control strategy was proposed with the main focus on the tertiary control which was defined as optimal power flow problem. The interior-point algorithm was applied to optimise experimental benchmark grid with the presence of Distributed Energy Resources (DERs. Moreover, two primary objectives were formulated: active power losses and amount of reactive power used to reach the voltage profile. As a result the active power losses were minimised to the high extent achieving the savings around 22% during entire day.

  7. Guidelines for Distribution System Operators on Reactive Power Provision by Electric Vehicles in Low Voltage Grids

    DEFF Research Database (Denmark)

    Zecchino, Antonio; Marinelli, Mattia; Træholt, Chresten

    2017-01-01

    The increasing success of electric vehicles is bringing new technical challenges to power system operators. This work intends to provide guidelines for distribution system operators in terms of reactive power requirements when evaluating and authorizing electric vehicles supply equipment with fast...... the amount of reactive power that an individual electric vehicle is expected to provide when connected to a low voltage feeder, in order to benefit of the desired voltage rise effect in comparison to the case of unitary power factor....... charging capability in existing low voltage distribution feeders. The aim is to prevent the voltage to exceed the permitted values when charging at high power, by exploiting the effect of the reactive power. The proposed guidelines for distribution system operators are reported in a matrix, which indicates...

  8. A hierarchical voltage control method for multi-terminal AC/DC distribution system

    Science.gov (United States)

    Ma, Zhoujun; Zhu, Hong; Zhou, Dahong; Wang, Chunning; Tang, Renquan; Xu, Honghua

    2017-08-01

    A hierarchical control system is proposed in this paper to control the voltage of multi-terminal AC/DC distribution system. The hierarchical control system consists of PCC voltage control system, DG voltage control system and voltage regulator control system. The functions of three systems are to control the voltage of DC distribution network, AC bus voltage and area voltage. A method is proposed to deal with the whole control system. And a case study indicates that when voltage fluctuating, three layers of power flow control system is running orderly, and can maintain voltage stability.

  9. High Voltage in Noble Liquids for High Energy Physics

    Energy Technology Data Exchange (ETDEWEB)

    Rebel, B. [Fermilab; Bernard, E. [Yale U.; Faham, C. H. [LBL, Berkeley; Ito, T. M. [Los Alamos; Lundberg, B. [Maryland U.; Messina, M. [Columbia U.; Monrabal, F. [Valencia U., IFIC; Pereverzev, S. P. [LLNL, Livermore; Resnati, F. [Zurich, ETH; Rowson, P. C. [SLAC; Soderberg, M. [Fermilab; Strauss, T. [Bern U.; Tomas, A. [Imperial Coll., London; Va' vra, J. [SLAC; Wang, H. [UCLA

    2014-08-22

    A workshop was held at Fermilab November 8-9, 2013 to discuss the challenges of using high voltage in noble liquids. The participants spanned the fields of neutrino, dark matter, and electric dipole moment physics. All presentations at the workshop were made in plenary sessions. This document summarizes the experiences and lessons learned from experiments in these fields at developing high voltage systems in noble liquids.

  10. Maintenance Optimization of High Voltage Substation Model

    Directory of Open Access Journals (Sweden)

    Radim Bris

    2008-01-01

    Full Text Available The real system from practice is selected for optimization purpose in this paper. We describe the real scheme of a high voltage (HV substation in different work states. Model scheme of the HV substation 22 kV is demonstrated within the paper. The scheme serves as input model scheme for the maintenance optimization. The input reliability and cost parameters of all components are given: the preventive and corrective maintenance costs, the actual maintenance period (being optimized, the failure rate and mean time to repair - MTTR.

  11. Incentive-Based Voltage Regulation in Distribution Networks

    Energy Technology Data Exchange (ETDEWEB)

    Dall-Anese, Emiliano [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Baker, Kyri A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Zhou, Xinyang [University of Colorado; Chen, Lijun [University of Colorado

    2017-07-03

    This paper considers distribution networks fea- turing distributed energy resources, and designs incentive-based mechanisms that allow the network operator and end-customers to pursue given operational and economic objectives, while concurrently ensuring that voltages are within prescribed limits. Two different network-customer coordination mechanisms that require different amounts of information shared between the network operator and end-customers are developed to identify a solution of a well-defined social-welfare maximization prob- lem. Notably, the signals broadcast by the network operator assume the connotation of prices/incentives that induce the end- customers to adjust the generated/consumed powers in order to avoid the violation of the voltage constraints. Stability of the proposed schemes is analytically established and numerically corroborated.

  12. Incentive-Based Voltage Regulation in Distribution Networks: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xinyang; Chen, Lijun; Dall' Anese, Emiliano; Baker, Kyri

    2017-03-03

    This paper considers distribution networks fea- turing distributed energy resources, and designs incentive-based mechanisms that allow the network operator and end-customers to pursue given operational and economic objectives, while concurrently ensuring that voltages are within prescribed limits. Two different network-customer coordination mechanisms that require different amounts of information shared between the network operator and end-customers are developed to identify a solution of a well-defined social-welfare maximization prob- lem. Notably, the signals broadcast by the network operator assume the connotation of prices/incentives that induce the end- customers to adjust the generated/consumed powers in order to avoid the violation of the voltage constraints. Stability of the proposed schemes is analytically established and numerically corroborated.

  13. High Voltage GaN Schottky Rectifiers

    Energy Technology Data Exchange (ETDEWEB)

    CAO,X.A.; CHO,H.; CHU,S.N.G.; CHUO,C.-C.; CHYI,J.-I.; DANG,G.T.; HAN,JUNG; LEE,C.-M.; PEARTON,S.J.; REN,F.; WILSON,R.G.; ZHANG,A.P.

    1999-10-25

    Mesa and planar GaN Schottky diode rectifiers with reverse breakdown voltages (V{sub RB}) up to 550V and >2000V, respectively, have been fabricated. The on-state resistance, R{sub ON}, was 6m{Omega}{center_dot} cm{sup 2} and 0.8{Omega}cm{sup 2}, respectively, producing figure-of-merit values for (V{sub RB}){sup 2}/R{sub ON} in the range 5-48 MW{center_dot}cm{sup -2}. At low biases the reverse leakage current was proportional to the size of the rectifying contact perimeter, while at high biases the current was proportional to the area of this contact. These results suggest that at low reverse biases, the leakage is dominated by the surface component, while at higher biases the bulk component dominates. On-state voltages were 3.5V for the 550V diodes and {ge}15 for the 2kV diodes. Reverse recovery times were <0.2{micro}sec for devices switched from a forward current density of {approx}500A{center_dot}cm{sup -2} to a reverse bias of 100V.

  14. A High-Voltage Level Tolerant Transistor Circuit

    NARCIS (Netherlands)

    Annema, Anne J.; Geelen, Godefridus Johannes Gertrudis Maria

    2001-01-01

    A high-voltage level tolerant transistor circuit, comprising a plurality of cascoded transistors, including a first transistor (T1) operatively connected to a high-voltage level node (3) and a second transistor (T2) operatively connected to a low-voltage level node (2). The first transistor (T1)

  15. Prediction of breakdown voltages in novel gases for high voltage insulation

    Energy Technology Data Exchange (ETDEWEB)

    Koch, M.

    2015-07-01

    This thesis submitted to the Swiss Federal Institute of Technology ETH in Zurich examines the use of sulphur hexafluoride (SF{sub 6}) and similar gases as important insulation media for high voltage equipment. Due to its superior insulation properties, SF{sub 6} is widely used in gas-insulated switchgear. However, the gas also has a very high global warming potential and the content of SF{sub 6} in the atmosphere is constantly increasing. The search for new insulation gases using classical breakdown experiments is discussed. A model for SF{sub 6} based on the stepped leader model is described. This calculates the breakdown voltages in arbitrary electrode configurations and under standard voltage waveforms. Thus, the thesis provides a method for the prediction of breakdown voltages of arbitrary field configurations under standard voltage waveforms for gases with electron-attaching properties. With this, further gases can be characterized for usage as high voltage insulation media.

  16. Activate distributed energy resources' services: Hierarchical voltage controller as an application

    DEFF Research Database (Denmark)

    Han, Xue; Kosek, Anna Magdalena; Gehrke, Oliver

    2014-01-01

    The flexibilities from controllable distributed energy resources (DERs) offer the opportunities to mitigate some of the operation problems in the power distribution grid. The provision of system services requires the aggregation and coordination of their flexibilities, in order to obtain...... the efficient aggregation and dispatch, and it simplifies the optimization complexity; the involvement of DER flexibilities in voltage services can significantly improve the voltage quality and reduce the grid power loss without additional regulating devices....... the flexible capacity of large scale. In this paper, a hierarchical controller is presented to activate the aggregation, and tries to obtain a global optimum of the grid operation. A distribution grid with large penetration of highly varying generation or load is under the risk that the voltage quality...

  17. RICH High Voltages & PDF Analysis @ LHCb

    CERN Multimedia

    Fanchini, E

    2009-01-01

    In the LHCb experiment an important issue is the identification of the hadrons of the final states of the B mesons decays. Two RICH subdetectors are devoted to this task, and the Hybrid Photon Detectors (HPDs) are the photodetectors used to detect Cherenkov light. In this poster there is a description of how the very high voltage (-18 KV) supply stability used to power the HPDs is monitored. It is also presented the basics of a study which can be done with the first collision data: the analysis of the dimuons from the Drell-Yan process. This process is well known and the acceptance of the LHCb detector in terms of pseudorapidity will be very useful to improve the knowledge of the proton structure functions or, alternatively, try to estimate the luminosity from it.

  18. Impact of Distributed Generation on the Voltage Sag Performance of Transmission Systems

    Directory of Open Access Journals (Sweden)

    Pierluigi Caramia

    2017-07-01

    Full Text Available In this paper, we analysed the growing penetration of generating units from renewable energy sources in transmission power systems. Among the possible effects of the interaction of distributed generation (DG with transmission systems, we considered the abnormal operating conditions caused by short circuits in the transmission systems and the resulting voltage sags that occur in the network. A systematic method is presented for analysing the voltage sag behaviour of any transmission system in which large DG units are connected to the transmission system by means of High Voltage/Medium Voltage (HV/MV stations. The method proposed for obtaining the voltage sags is the fault position method (FPM, from which we derived a graphical visualization of the during-fault voltage (DFV matrix as a valuable tool to obtain an immediate measure of the propagation of voltage sags in the network. The results obtained were based on a portion of a real transmission system. The system that we considered is an actual portion of the Italian transmission system, and all of the quantities we used were obtained from the data of the Transmission system operator (TSO.

  19. Large Scale Solar Power Integration in Distribution Grids : PV Modelling, Voltage Support and Aggregation Studies

    NARCIS (Netherlands)

    Samadi, A.

    2014-01-01

    Long term supporting schemes for photovoltaic (PV) system installation have led to accommodating large numbers of PV systems within load pockets in distribution grids. High penetrations of PV systems can cause new technical challenges, such as voltage rise due to reverse power flow during light load

  20. Temperature and Voltage Offsets in High-ZT Thermoelectrics

    Science.gov (United States)

    Levy, George S.

    2017-10-01

    Thermodynamic temperature can take on different meanings. Kinetic temperature is an expectation value and a function of the kinetic energy distribution. Statistical temperature is a parameter of the distribution. Kinetic temperature and statistical temperature, identical in Maxwell-Boltzmann statistics, can differ in other statistics such as those of Fermi-Dirac or Bose-Einstein when a field is present. Thermal equilibrium corresponds to zero statistical temperature gradient, not zero kinetic temperature gradient. Since heat carriers in thermoelectrics are fermions, the difference between these two temperatures may explain voltage and temperature offsets observed during meticulous Seebeck measurements in which the temperature-voltage curve does not go through the origin. In conventional semiconductors, temperature offsets produced by fermionic electrical carriers are not observable because they are shorted by heat phonons in the lattice. In high-ZT materials, however, these offsets have been detected but attributed to faulty laboratory procedures. Additional supporting evidence for spontaneous voltages and temperature gradients includes data collected in epistatic experiments and in the plasma Q-machine. Device fabrication guidelines for testing the hypothesis are suggested including using unipolar junctions stacked in a superlattice, alternating n/n + and p/p + junctions, selecting appropriate dimensions, doping, and loading.

  1. Voltage Impact of a Wave Energy Converter on an Unbalanced Distribution Grid and Corrective Actions

    Directory of Open Access Journals (Sweden)

    Hugo Mendonça

    2017-10-01

    Full Text Available Renewable energy is steadily increasing its penetration level in electric power systems. Wind and solar energy have reached a high degree of maturity, and their impacts on the grid are well known. However, this is not the case for emerging sources like wave energy. This work explores the impact of the fluctuating power injected by a wave energy converter on the distribution grid voltage and proposes a strategy for mitigating the induced voltage fluctuations. The paper describes the mechanics of how a fluctuating active power injection leads to grid voltage fluctuations and presents an unbalanced three-phase power flow tool that allows one to quantitatively analyze the voltage evolution at every phase and bus of a distribution grid driven by this power injection. The paper also proposes a corrective action for mitigating the voltage fluctuations that makes use of the hardware resources already available in the wave energy converter, by means of a control strategy on the reactive capability of the grid-side inverter. The use of a STATCOM as additional reactive compensation equipment is also explored. The effectiveness of the proposal is assessed in the IEEE 13-bus test feeder showing that, in some cases, the wave energy converter by itself is able to mitigate the voltage fluctuations that it causes. If not, a STATCOM can provide the extra reactive capability needed.

  2. A Communication-Less Distributed Voltage Control Strategy for a Multi-Bus AC Islanded Microgrid

    DEFF Research Database (Denmark)

    Wang, Yanbo; Tan, Yongdong; Chen, Zhe

    2014-01-01

    optimal controller using MPC (Model Predictive Control) are developed to implement voltage optimal control. The contributions of this paper are demonstrated: (1) The proposed voltage estimator can dynamically obtain network voltage responses just through local voltage and current associated with each DG......This paper presents a communication-less distributed voltage control strategy for a multi-bus AC islanded microgrid. First, a Kalman Filter-based network voltage estimator is proposed to obtain voltage responses without communication links in the presence of load disturbances. Then, a voltage...

  3. External loading of High Voltage Pylons

    Directory of Open Access Journals (Sweden)

    Peter Polák

    2013-12-01

    Full Text Available This contribution is devoted to issues of long term safe service of high-voltage pylons, which are loaded during service by variable loading with simultaneous acting of external environment. There were proved the procedures ensuring that the limit state will not occur during the period of technical life and the service will be safe for a long time. A draft of diagnostic procedures was elaborated, applied in suitable inspection intervals, following from the analysis of failure risks. The maintenance and repair procedures, assuring the safety of service until next inspection are planned on the basis of application of analytic methods of dynamic fracture mechanics. This procedure of controlled ageing is designed for the new and serviced pylons as well. The controlled ageing at the same time prolongs the technical life of structure with a high measure of safety. Residual life can be determined in each phase of pylon life. Controlled ageing allows saving high economic values at spending considerable lower costs for inspection and maintenance.

  4. Design and development of high voltage high power operational ...

    Indian Academy of Sciences (India)

    systems and the electron deflection systems. Power operational amplifiers have ... approach is cost and availability of high voltage devices in chip form. 2.2 Amplifier with opamp input stage .... power opamp, using chip passive components, semiconductor bare dice minimizes the size while increasing the reliability.

  5. Low-voltage and high-voltage TEM observations on MWCNTs of rat in vivo.

    Science.gov (United States)

    Sakaguchi, Norihito; Watari, Fumio; Yokoyama, Atsuro; Nodasaka, Yoshinobu; Ichinose, Hideki

    2009-01-01

    In the present study, we focused on the optimal conditions for observation of morphology and atomic structure of carbon nanotube (CNT) in vivo by transmission electron microscopy (TEM). Either low-voltage or high-voltage TEMs was chosen for the high-contrast or high-resolution imaging of subcutaneous tissue and the multi-wall CNT (MWCNT). The morphology and structure of each cell organelle were well recognized using the low-voltage TEM at 75 kV. Individual MWCNTs forming the cluster were also visible by the low-voltage TEM. On the contrary, the high-voltage TEM image at 1250 kV shows poor contrast on both the cell organelles and MWCNTs. However, graphene layers of MWCNT were clearly visible in the HRTEM image using the high-voltage TEM. The influence of the surrounding biological tissue can be disregarded by the high-energy electrons due to their weak scattering/absorption effect in the tissue. It was indicated that the usage of the high-voltage TEM is quite effective to the atomic structure analysis of nano-crystalline materials in vivo.

  6. Response of low voltage networks with high penetration of photovoltaic systems to transmission network faults

    NARCIS (Netherlands)

    Skaloumpakas, K.; Boemer, J.C.; Van Ruitenbeek, E.; Gibescu, M.

    2014-01-01

    The installed capacity of photovoltaic (PV) systems connected to low voltage (LV) networks in Germany has increased to more than 25 GW. Current grid codes still mandate these PV systems to disconnect in case of voltage dips below 0.8 p.u. The resulting response of LV distribution systems with high

  7. LED-Based High-Voltage Lines Warning System

    Directory of Open Access Journals (Sweden)

    Eldar MUSA

    2013-04-01

    Full Text Available LED-based system, running with the current of high-voltage lines and converting the current flowing through the line into the light by using a toroid transformer, has been developed. The transformer’s primary winding is constituted by the high voltage power line. Toroidal core consists of two equal parts and the secondary windings are evenly placed on these two parts. The system is mounted on the high-voltage lines as a clamp. The secondary winding ends are connected in series by the connector on the clamp. LEDs are supplied by the voltage at the ends of secondary. Current flowing through highvoltage transmission lines is converted to voltage by the toroidal transformer and the light emitting LEDs are supplied with this voltage. The theory of the conversion of the current flowing through the line into the light is given. The system, running with the current of the line and converting the current into the light, has been developed. System has many application areas such as warning high voltage lines (warning winches to not hinder the high-voltage lines when working under the lines, warning planes to not touch the high-voltage lines, remote measurement of high-voltage line currents, and local illumination of the line area

  8. High impedance fault detection in low voltage networks

    Energy Technology Data Exchange (ETDEWEB)

    Christie, R.D. (Univ. of Washington, Seattle, WA (United States). Dept. of Electrical Engineering); Zadehgol, H.; Habib, M.M. (Seattle City Light, WA (United States))

    1993-10-01

    High impedance faults are those with fault current magnitude similar to load currents. Experimental results were obtained that conform operating experience that such faults can occur in the low voltage (600V and below) underground distribution networks typically found in urban power systems. These faults produce current waveforms qualitatively similar to those found on overhead feeders, but quantitatively smaller. Loose connectors can produce similar, but cleaner current characteristics. Noisy loads remain a major impediment to reliable detection. Design and installation of an inexpensive prototype fault detector on the Seattle City Light street network is described.

  9. Containment and Consensus-based Distributed Coordination Control for Voltage Bound and Reactive Power Sharing in AC Microgrid

    DEFF Research Database (Denmark)

    Han, Renke; Meng, Lexuan; Ferrari-Trecate, Giancarlo

    2017-01-01

    This paper offers a highly flexible and reliable control strategy to achieve voltage bounded regulation and accurate reactive power sharing coordinately in AC Micro-Grids. A containment and consensus-based distributed coordination controller is proposed, by which each output voltage magnitude can...

  10. Effect of the electrode material on the breakdown voltage and space charge distribution of propylene carbonate under impulse voltage

    OpenAIRE

    Qing Yang; Yang Jin; Wenxia Sima; Mengna Liu

    2016-01-01

    This paper reports three types of electrode materials (copper, aluminum, and stainless steel) that are used to measure the impulse breakdown voltage of propylene carbonate. The breakdown voltage of propylene carbonate with these electrode materials is different and is in decreasing order of stainless steel, copper, and aluminum. To explore how the electrode material affects the insulating properties of the liquid dielectric, the electric field distribution and space charge distribution of pro...

  11. High Voltage Application of Explosively Formed Fuses

    Energy Technology Data Exchange (ETDEWEB)

    Tasker, D.G.; Goforth, J.H.; Fowler, C.M.; Lopez, E.M.; Oona, H.; Marsh, S.P.; King, J.C.; Herrera, D.H.; Torres, D.T.; Sena, F.C.; Martinez, E.C.; Reinovsky, R.E.; Stokes, J.L.; Tabaka, L.J.; Kiuttu, G.; Degnan, J.

    1998-10-18

    At Los Alamos, the authors have primarily applied Explosively Formed Fuse (EFF) techniques to high current systems. In these systems, the EFF has interrupted currents from 19 to 25 MA, thus diverting the current to low inductance loads. The magnitude of transferred current is determined by the ratio of storage inductance to load inductance, and with dynamic loads, the current has ranged from 12 to 20 MA. In a system with 18 MJ stored energy, the switch operates at a power up to 6 TW. The authors are now investigating the use of the EFF technique to apply high voltages to high impedance loads in systems that are more compact. In these systems, they are exploring circuits with EFF lengths from 43 to 100 cm, which have storage inductances large enough to apply 300 to 500 kV across high impedance loads. Experimental results and design considerations are presented. Using cylindrical EFF switches of 10 cm diameter and 43 cm length, currents of approximately 3 MA were interrupted producing {approximately}200 kV. This indicate s the switch had an effective resistance of {approximately}100 m{Omega} where 150--200 m{Omega} was expected. To understand the lower performance, several parameters were studied, including: electrical conduction through the explosive products; current density; explosive initiation; insulator type; conductor thickness; and so on. The results show a number of interesting features, most notably that the primary mechanism of switch operation is mechanical and not electrical fusing of the conductor. Switches opening on a 10 to 10 {micro}s time scale with resistances starting at 50 {micro}{Omega} and increasing to perhaps 1 {Omega} now seem possible to construct, using explosive charges as small as a few pounds.

  12. Study of the plasma interference with high voltage electrode array for space power application

    OpenAIRE

    Iwasa, Minoru; Tanaka, Koji; Sasaki, Susumu; Odawara, Osamu; 岩佐 稔; 田中 孝治; 佐々木 進; 小田原 修

    2005-01-01

    We are studying the problems associated with high voltage power systems in space. Especially we are interested in the potential distribution of the solar array that is resistant to the electrical discharge. We have carried out experiments on the interaction between the high voltage solar array and the ambient plasma. In the experiment, an array of electrodes distributed on the insulation panel was used to simulate the inter-connectors of the solar array. An electrode array without the insulat...

  13. Artificial neural networks in high voltage transmission line problems

    Science.gov (United States)

    Ekonomou, L.; Kontargyri, V. T.; Kourtesi, St.; Maris, T. I.; Stathopulos, I. A.

    2007-07-01

    According to the literature high voltage transmission line problems are faced using conventional analytical methods, which include in most cases empirical and/or approximating equations. Artificial intelligence and more specifically artificial neural networks (ANN) are addressed in this work, in order to give accurate solutions to high voltage transmission line problems using in the calculations only actual field data. Two different case studies are studied, i.e., the estimation of critical flashover voltage on polluted insulators and the estimation of lightning performance of high voltage transmission lines. ANN models are developed and are tested on operating high voltage transmission lines and polluted insulators, producing very satisfactory results. These two ANN models can be used in electrical engineers' studies aiming at the more effective protection of high voltage equipment.

  14. CFD Simulation of Transonic Flow in High-Voltage Circuit Breaker

    Directory of Open Access Journals (Sweden)

    Xiangyang Ye

    2012-01-01

    Full Text Available A high-voltage circuit breaker is an indispensable piece of equipment in the electric transmission and distribution systems. Transonic flow typically occurs inside breaking chamber during the current interruption, which determines the insulating characteristics of gas. Therefore, accurate compressible flow simulations are required to improve the prediction of the breakdown voltages in various test duties of high-voltage circuit breakers. In this work, investigation of the impact of the solvers on the prediction capability of the breakdown voltages in capacitive switching is presented. For this purpose, a number of compressible nozzle flow validation cases have been presented. The investigation is then further extended for a real high-voltage circuit breaker geometry. The correlation between the flow prediction accuracy and the breakdown voltage prediction capability is identified.

  15. Voltage-Sensitive Load Controllers for Voltage Regulation and Increased Load Factor in Distribution Systems

    DEFF Research Database (Denmark)

    Douglass, Philip James; Garcia-Valle, Rodrigo; Østergaard, Jacob

    2014-01-01

    This paper presents a novel controller design for controlling appliances based on local measurements of voltage. The controller finds the normalized voltage deviation accounting for the sensitivity of voltage measurements to appliance state. The controller produces a signal indicating desired pow...

  16. Impacts of distributed generation on low-voltage distribution network protection

    OpenAIRE

    Ogden, Richard; Yang, Jin

    2015-01-01

    This paper reports work of a MEng student final year project, which looks in detail at the impacts that distributed generation can have on existing low-voltage distribution network protection systems. After a review of up-to-date protection issues, this paper will investigate several key issues that face distributed generation connections when it comes to network protection systems. These issues include, the blinding of protection systems, failure to automatically reclose, unintentional islan...

  17. High-Voltage Digital-To-Analog Converter

    Science.gov (United States)

    Huston, Steven W.

    1990-01-01

    High-voltage 10-bit digital-to-analog converter operates under computer control to put out voltages up to 500 V at currents up to 35 mA. Circuit includes high-voltage power supply used to generate high-voltage square wave at frequency set by computer at value between 0.2 Hz and 10 Hz. Used to drive 0.02-microfarad, 1-kV capacitor at slewing rate of 1 V/microsecond to provide signal for robotic imaging system.

  18. Distributed Reactive Power Control based Conservation Voltage Reduction in Active Distribution Systems

    Directory of Open Access Journals (Sweden)

    EMIROGLU, S.

    2017-11-01

    Full Text Available This paper proposes a distributed reactive power control based approach to deploy Volt/VAr optimization (VVO / Conservation Voltage Reduction (CVR algorithm in a distribution network with distributed generations (DG units and distribution static synchronous compensators (D-STATCOM. A three-phase VVO/CVR problem is formulated and the reactive power references of D-STATCOMs and DGs are determined in a distributed way by decomposing the VVO/CVR problem into voltage and reactive power control. The main purpose is to determine the coordination between voltage regulator (VR and reactive power sources (Capacitors, D-STATCOMs and DGs based on VVO/CVR. The study shows that the reactive power injection capability of DG units may play an important role in VVO/CVR. In addition, it is shown that the coordination of VR and reactive power sources does not only save more energy and power but also reduces the power losses. Moreover, the proposed VVO/CVR algorithm reduces the computational burden and finds fast solutions. To illustrate the effectiveness of the proposed method, the VVO/CVR is performed on the IEEE 13-node test system feeder considering unbalanced loading and line configurations. The tests are performed taking the practical voltage-dependent load modeling and different customer types into consideration to improve accuracy.

  19. Integration of Electric Vehicles in Low Voltage Danish Distribution Grids

    DEFF Research Database (Denmark)

    Pillai, Jayakrishnan Radhakrishna; Thøgersen, Paul; Møller, Jan

    2012-01-01

    in the electricity grid operation, a careful examination in the local electricity system is essential. This paper investigates the degree of EV penetration and its key influence on the low voltage distribution grids. Three detailed models of residential grids in Denmark are considered as test cases in this study......Electric Vehicles (EVs) are considered as one of the important components of the future intelligent grids. Their role as energy storages in the electricity grid could provide local sustainable solutions to support more renewable energy. In order to estimate the extent of interaction of EVs...... are reflected as the major technical constraint to the stable operation of the electricity grids for integrating more EVs, when compared to the thermal loading on the cables....

  20. ON SELECTION OF CIRCUIT-BREAKERS SWITCHING ELECTRICAL INSTALLATIONS OF HIGH AND EXTRA-HIGH VOLTAGE

    Directory of Open Access Journals (Sweden)

    T. M. Lazimov

    2005-01-01

    Full Text Available The paper proposes some additional conditions for high-voltage circuit-breaker selection keeping in mind coordination of the switched over-voltages and voltages induced in secondary circuits with their permissible values.

  1. High voltage switches having one or more floating conductor layers

    Science.gov (United States)

    Werne, Roger W.; Sampayan, Stephen; Harris, John Richardson

    2015-11-24

    This patent document discloses high voltage switches that include one or more electrically floating conductor layers that are isolated from one another in the dielectric medium between the top and bottom switch electrodes. The presence of the one or more electrically floating conductor layers between the top and bottom switch electrodes allow the dielectric medium between the top and bottom switch electrodes to exhibit a higher breakdown voltage than the breakdown voltage when the one or more electrically floating conductor layers are not present between the top and bottom switch electrodes. This increased breakdown voltage in the presence of one or more electrically floating conductor layers in a dielectric medium enables the switch to supply a higher voltage for various high voltage circuits and electric systems.

  2. Integrated reconfigurable high-voltage transmitting circuit for CMUTs

    DEFF Research Database (Denmark)

    Llimos Muntal, Pere; Larsen, Dennis Øland; Jørgensen, Ivan Harald Holger

    2015-01-01

    In this paper a high-voltage transmitting circuit aimed for capacitive micromachined ultrasonic transducers (CMUTs) used in scanners for medical applications is designed and implemented in a 0.35 μm high-voltage CMOS process. The transmitting circuit is reconfigurable externally making it able...

  3. An estimator-based distributed voltage-predictive control strategy for ac islanded microgrids

    DEFF Research Database (Denmark)

    Wang, Yanbo; Chen, Zhe; Wang, Xiongfei

    2015-01-01

    distributed generator, where the voltage estimator serves as an essential tool to obtain network voltages response without using communication links, while the voltage predictive controller is able to implement offset-free voltage control for a specified bus. The dynamic performance of the proposed voltage......This paper presents an estimator-based voltage predictive control strategy for AC islanded microgrids, which is able to perform voltage control without any communication facilities. The proposed control strategy is composed of a network voltage estimator and a voltage predictive controller for each...... perturbation, load parameters variation, different disturbance locations, LC filters perturbation, output impedances perturbation and DG unit fault. The simulation and experimental results show that the proposed control approach is able to perform offset-free voltage control without any communication links...

  4. Effect of the electrode material on the breakdown voltage and space charge distribution of propylene carbonate under impulse voltage

    Directory of Open Access Journals (Sweden)

    Qing Yang

    2016-04-01

    Full Text Available This paper reports three types of electrode materials (copper, aluminum, and stainless steel that are used to measure the impulse breakdown voltage of propylene carbonate. The breakdown voltage of propylene carbonate with these electrode materials is different and is in decreasing order of stainless steel, copper, and aluminum. To explore how the electrode material affects the insulating properties of the liquid dielectric, the electric field distribution and space charge distribution of propylene carbonate under impulse voltage with the three electrode materials are measured on the basis of a Kerr electro-optic test. The space charge injection ability is highest for aluminum, followed by copper, and then the stainless steel electrodes. Furthermore, the electric field distortion rate decreased in the order of the aluminum, copper, and then the stainless steel electrode. This paper explains that the difference in the electric field distortion rate between the three electrode materials led to the difference in the impulse breakdown voltage of propylene carbonate.

  5. Optimal Voltage Regulation for Unbalanced Distribution Networks Considering Distributed Energy Resources

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yan [ORNL; Tomsovic, Kevin [University of Tennessee, Knoxville (UTK)

    2015-01-01

    With increasing penetration of distributed generation in the distribution networks (DN), the secure and optimal operation of DN has become an important concern. In this paper, an iterative quadratic constrained quadratic programming model to minimize voltage deviations and maximize distributed energy resource (DER) active power output in a three phase unbalanced distribution system is developed. The optimization model is based on the linearized sensitivity coefficients between controlled variables (e.g., node voltages) and control variables (e.g., real and reactive power injections of DERs). To avoid the oscillation of solution when it is close to the optimum, a golden search method is introduced to control the step size. Numerical simulations on modified IEEE 13 nodes test feeders show the efficiency of the proposed model. Compared to the results solved by heuristic search (harmony algorithm), the proposed model converges quickly to the global optimum.

  6. A Conservation Voltage Reduction Scheme for a Distribution Systems with Intermittent Distributed Generators

    Directory of Open Access Journals (Sweden)

    Pyeong-Ik Hwang

    2016-08-01

    Full Text Available In this paper, a conservation voltage reduction (CVR scheme is proposed for a distribution system with intermittent distributed generators (DGs, such as photovoltaics and wind turbines. The CVR is a scheme designed to reduce energy consumption by lowering the voltages supplied to customers. Therefore, an unexpected under-voltage violation can occur due to the variation of active power output from the intermittent DGs. In order to prevent the under-voltage violation and improve the CVR effect, a new reactive power controller which complies with the IEEE Std. 1547TM, and a parameter determination method for the controller are proposed. In addition, an optimal power flow (OPF problem to determine references for the resources of CVR is formulated with consideration of the intermittent DGs. The proposed method is validated using a modified IEEE 123-node test feeder. With the proposed method, the voltages of the test system are maintained to be greater than the lower bound, even though the active power outputs of the DGs are varied. Moreover, the CVR effect is improved compared to that used with the conventional reactive power control methods.

  7. 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

  8. PV source based high voltage gain current fed converter

    Science.gov (United States)

    Saha, Soumya; Poddar, Sahityika; Chimonyo, Kudzai B.; Arunkumar, G.; Elangovan, D.

    2017-11-01

    This work involves designing and simulation of a PV source based high voltage gain, current fed converter. It deals with an isolated DC-DC converter which utilizes boost converter topology. The proposed converter is capable of high voltage gain and above all have very high efficiency levels as proved by the simulation results. The project intends to produce an output of 800 V dc from a 48 V dc input. The simulation results obtained from PSIM application interface were used to analyze the performance of the proposed converter. Transformer used in the circuit steps up the voltage as well as to provide electrical isolation between the low voltage and high voltage side. Since the converter involves high switching frequency of 100 kHz, ultrafast recovery diodes are employed in the circuitry. The major application of the project is for future modeling of solar powered electric hybrid cars.

  9. Multiple High Voltage Pulse Stressing of Polymer Thick Film Resistors

    Directory of Open Access Journals (Sweden)

    Busi Rambabu

    2014-01-01

    Full Text Available The purpose of this paper is to study high voltage interactions in polymer thick film resistors, namely, polyvinyl chloride- (PVC- graphite thick film resistors, and their applications in universal trimming of these resistors. High voltages in the form of impulses for various pulse durations and with different amplitudes have been applied to polymer thick film resistors and we observed the variation of resistance of these resistors with high voltages. It has been found that the resistance of polymer thick film resistors decreases in the case of higher resistivity materials and the resistance of polymer thick film resistor increases in the case of lower resistivity materials when high voltage impulses are applied to them. It has been also found that multiple high voltage pulse (MHVP stressing can be used to trim the polymer thick film resistors either upwards or downwards.

  10. Artifical Excitation of Ferro-Resonance for Testing Electrotechnical Equipment in Distribution Devices with Increased Voltage

    Directory of Open Access Journals (Sweden)

    Ye. V. Dmitriev

    2006-01-01

    Full Text Available On the basis of the developed device for protection against of ferro-resonant and high-frequency cumulative over-voltages an algorithm for obtaining a voltage imitating ferro-resonant over-voltages is proposed in the paper. This algorithm presupposes to apply a voltage to the secondary transformer side from an extraneous source is proposed.

  11. Electrical system architecture having high voltage bus

    Science.gov (United States)

    Hoff, Brian Douglas [East Peoria, IL; Akasam, Sivaprasad [Peoria, IL

    2011-03-22

    An electrical system architecture is disclosed. The architecture has a power source configured to generate a first power, and a first bus configured to receive the first power from the power source. The architecture also has a converter configured to receive the first power from the first bus and convert the first power to a second power, wherein a voltage of the second power is greater than a voltage of the first power, and a second bus configured to receive the second power from the converter. The architecture further has a power storage device configured to receive the second power from the second bus and deliver the second power to the second bus, a propulsion motor configured to receive the second power from the second bus, and an accessory motor configured to receive the second power from the second bus.

  12. Planar LTCC transformers for high voltage flyback converters.

    Energy Technology Data Exchange (ETDEWEB)

    Schofield, Daryl (NASCENT Technology Inc. , Watertown, SD); Schare, Joshua M.; Glass, Sarah Jill; Roesler, Alexander William; Ewsuk, Kevin Gregory; Slama, George (NASCENT Technology Inc. , Watertown, SD); Abel, Dave (NASCENT Technology Inc. , Watertown, SD)

    2007-06-01

    This paper discusses the design and use of low-temperature (850 C to 950 C) co-fired ceramic (LTCC) planar magnetic flyback transformers for applications that require conversion of a low voltage to high voltage (> 100V) with significant volumetric constraints. Measured performance and modeling results for multiple designs showed that the LTCC flyback transformer design and construction imposes serious limitations on the achievable coupling and significantly impacts the transformer performance and output voltage. This paper discusses the impact of various design factors that can provide improved performance by increasing transformer coupling and output voltage. The experiments performed on prototype units demonstrated LTCC transformer designs capable of greater than 2 kV output. Finally, the work investigated the effect of the LTCC microstructure on transformer insulation. Although this paper focuses on generating voltages in the kV range, the experimental characterization and discussion presented in this work applies to designs requiring lower voltage.

  13. Properties of Polymer Composites Used in High-Voltage Applications

    Directory of Open Access Journals (Sweden)

    Ilona Pleşa

    2016-04-01

    Full Text Available The present review article represents a comprehensive study on polymer micro/nanocomposites that are used in high-voltage applications. Particular focus is on the structure-property relationship of composite materials used in power engineering, by exploiting fundamental theory as well as numerical/analytical models and the influence of material design on electrical, mechanical and thermal properties. In addition to describing the scientific development of micro/nanocomposites electrical features desired in power engineering, the study is mainly focused on the electrical properties of insulating materials, particularly cross-linked polyethylene (XLPE and epoxy resins, unfilled and filled with different types of filler. Polymer micro/nanocomposites based on XLPE and epoxy resins are usually used as insulating systems for high-voltage applications, such as: cables, generators, motors, cast resin dry-type transformers, etc. Furthermore, this paper includes ample discussions regarding the advantages and disadvantages resulting in the electrical, mechanical and thermal properties by the addition of micro- and nanofillers into the base polymer. The study goals are to determine the impact of filler size, type and distribution of the particles into the polymer matrix on the electrical, mechanical and thermal properties of the polymer micro/nanocomposites compared to the neat polymer and traditionally materials used as insulation systems in high-voltage engineering. Properties such as electrical conductivity, relative permittivity, dielectric losses, partial discharges, erosion resistance, space charge behavior, electric breakdown, tracking and electrical tree resistance, thermal conductivity, tensile strength and modulus, elongation at break of micro- and nanocomposites based on epoxy resin and XLPE are analyzed. Finally, it was concluded that the use of polymer micro/nanocomposites in electrical engineering is very promising and further research work

  14. High Voltage Piezoelectric System for Generating Neutrons

    Science.gov (United States)

    2013-06-01

    10 mm × 1.5 mm -45-degree rotated y-cut lithium niobate slabs. Input electrodes, shown as gray regions on the top and bottom (not visible) surfaces on...the left portion of the bar in Fig. ??, were used to deliver electrical power to the crystal and applied using silver paint with a measured layer ...voltage, stress, and displacement. The crystals for the PTPS were disks of lithium niobate with 5 mm radius and 2 mm thickness, shown in Fig

  15. A Consensus-Based Cooperative Control of PEV Battery and PV Active Power Curtailment for Voltage Regulation in Distribution Networks

    DEFF Research Database (Denmark)

    Zeraati, Mehdi; Golshan, Mohamad Esmail Hamedani; Guerrero, Josep M.

    2018-01-01

    The rapid growth of rooftop photovoltaic (PV) arrays installed in residential houses leads to serious voltage quality problems in low voltage distribution networks (LVDNs). In this paper, a combined method using the battery energy management of plug-in electric vehicles (PEVs) and the active power...... curtailment (APC) of PV arrays is proposed to regulate voltage in LVDNs with high penetration level of PV resources. A distributed control strategy composed of two consensus algorithms is used to reach an effective utilization of limited storage capacity of PEV battery considering its power/capacity and state...... of charge (SoC). A consensus control algorithm is also developed to fairly share the required power curtailment among PVs during overvoltage periods. The main objective is to mitigate the voltage rise due to the reverse power flow and to compensate the voltage drop resulting from the peak load. Overall...

  16. Voltage Control Support and Coordination between Renewable Generation Plants in MV Distribution Systems

    DEFF Research Database (Denmark)

    Petersen, Lennart; Iov, Florin; D. Hansen, Anca

    2016-01-01

    This paper focusses on voltage control support and coordination between renewable generation plants in medium voltage distribution systems. An exemplary benchmark grid in Denmark, including a number of flexible ReGen plants providing voltage control functionality, is used as a base case. First...

  17. Impacts of Voltage Control Methods on Distribution Circuit’s Photovoltaic (PV Integration Limits

    Directory of Open Access Journals (Sweden)

    Anamika Dubey

    2017-10-01

    Full Text Available The widespread integration of photovoltaic (PV units may result in a number of operational issues for the utility distribution system. The advances in smart-grid technologies with better communication and control capabilities may help to mitigate these challenges. The objective of this paper is to evaluate multiple voltage control methods and compare their effectiveness in mitigating the impacts of high levels of PV penetrations on distribution system voltages. A Monte Carlo based stochastic analysis framework is used to evaluate the impacts of PV integration, with and without voltage control. Both snapshot power flow and time-series analysis are conducted for the feeder with varying levels of PV penetrations. The methods are compared for their impacts on (1 the feeder’s PV hosting capacity; (2 the number of voltage violations and the magnitude of the largest bus voltage; (3 the net reactive power demand from the substation; and (4 the number of switching operations of feeder’s legacy voltage support devices i.e., capacitor banks and load tap changers (LTCs. The simulation results show that voltage control help in mitigating overvoltage concerns and increasing the feeder’s hosting capacity. Although, the legacy control solves the voltage concerns for primary feeders, a smart inverter control is required to mitigate both primary and secondary feeder voltage regulation issues. The smart inverter control, however, increases the feeder’s reactive power demand and the number of LTC and capacitor switching operations. For the 34.5-kV test circuit, it is observed that the reactive power demand increases from 0 to 6.8 MVAR on enabling Volt-VAR control for PV inverters. The total number of capacitor and LTC operations over a 1-year period also increases from 455 operations to 1991 operations with Volt-VAR control mode. It is also demonstrated that by simply changing the control mode of capacitor banks, a significant reduction in the unnecessary

  18. A high-voltage rechargeable magnesium-sodium hybrid battery

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yifei; An, Qinyou; Cheng, Yingwen; Liang, Yanliang; Ren, Yang; Sun, Cheng-Jun; Dong, Hui; Tang, Zhongjia; Li, Guosheng; Yao, Yan

    2017-04-01

    Growing global demand of safe and low-cost energy storage technology triggers strong interests in novel battery concepts beyond state-of-art Li-ion batteries. Here we report a high-voltage rechargeable Mg–Na hybrid battery featuring dendrite-free deposition of Mg anode and Na-intercalation cathode as a low-cost and safe alternative to Li-ion batteries for large-scale energy storage. A prototype device using a Na3V2(PO4)3 cathode, a Mg anode, and a Mg–Na dual salt electrolyte exhibits the highest voltage (2.60 V vs. Mg) and best rate performance (86% capacity retention at 10C rate) among reported hybrid batteries. Synchrotron radiation-based X-ray absorption near edge structure (XANES), atomic-pair distribution function (PDF), and high-resolution X-ray diffraction (HRXRD) studies reveal the chemical environment and structural change of Na3V2(PO4)3 cathode during the Na ion insertion/deinsertion process. XANES study shows a clear reversible shift of vanadium K-edge and HRXRD and PDF studies reveal a reversible two-phase transformation and V–O bond length change during cycling. The energy density of the hybrid cell could be further improved by developing electrolytes with a higher salt concentration and wider electrochemical window. This work represents a significant step forward for practical safe and low-cost hybrid batteries.

  19. Loss minimization and voltage control in smart distribution grid

    DEFF Research Database (Denmark)

    Juelsgaard, Morten; Sloth, Christoffer; Wisniewski, Rafael

    2014-01-01

    This work presents a strategy for increasing the installation of electric vehicles and solar panels in low-voltage grids, while obeying voltage variation constraints. Our approach employs minimization of active power losses for coordinating consumption and generation of power, as well as reactive...... power control to maintain satisfactory grid operation. Numerical case studies illustrate how our approach can significantly increase installation of both electric vehicles and solar panels, while avoiding unsatisfactory over- and under-voltages throughout the grid....

  20. Loss Minimization and Voltage Control in Smart Distribution Grid

    DEFF Research Database (Denmark)

    Juelsgaard, Morten; Sloth, Christoffer; Wisniewski, Rafal

    2014-01-01

    This work presents a strategy for increasing the installation of electric vehicles and solar panels in low-voltage grids, while obeying voltage variation constraints. Our approach employs minimization of active power losses for coordinating consumption and generation of power, as well as reactive...... power control to maintain satisfactory grid operation. Numerical case studies illustrate how our approach can significantly increase installation of both electric vehicles and solar panels, while avoiding unsatisfactory over- and under-voltages throughout the grid....

  1. Flexible voltage support control for three-phase distributed generation inverters under grid fault

    DEFF Research Database (Denmark)

    Camacho, Antonio; Castilla, Miguel; Miret, Jaume

    2013-01-01

    Operators describe the behavior of the energy source, regulating voltage limits and reactive power injection to remain connected and support the grid under fault. On the basis that different kinds of voltage sags require different voltage support strategies, a flexible control scheme for three phase grid...... connected inverters is proposed. In three phase balanced voltage sags, the inverter should inject reactive power in order to raise the voltage in all phases. In one or two phase faults, the main concern of the distributed generation inverter is to equalize voltages by reducing the negative symmetric...... of this work is the introduction of a control algorithm for reference current generation that provides flexible voltage support under grid faults. Two different voltage sags have been experimentally tested to illustrate the behavior of the proposed voltage support control scheme....

  2. High voltage high repetition rate pulse using Marx topology

    Science.gov (United States)

    Hakki, A.; Kashapov, N.

    2015-06-01

    The paper describes Marx topology using MOSFET transistors. Marx circuit with 10 stages has been done, to obtain pulses about 5.5KV amplitude, and the width of the pulses was about 30μsec with a high repetition rate (PPS > 100), Vdc = 535VDC is the input voltage for supplying the Marx circuit. Two Ferrite ring core transformers were used to control the MOSFET transistors of the Marx circuit (the first transformer to control the charging MOSFET transistors, the second transformer to control the discharging MOSFET transistors).

  3. Mechanical Properties of Composites Used in High-Voltage Applications

    Directory of Open Access Journals (Sweden)

    Andreas Moser

    2016-07-01

    Full Text Available Materials used in high voltage applications have to meet a lot of regulations for their safety and functional usage during their lifetime. For high voltage applications the electrical properties are the most relevant designing criteria. However, the mechanical properties of such materials have rarely been considered for application dimensioning over the last decades. This article gives an overview of composite materials used in high voltage applications and some basic mechanical and thermo-mechanical characterization methods of such materials, including a discussion of influences on practically used epoxy based thermosets.

  4. Voltage quality enhancement in distribution system using artificial ...

    African Journals Online (AJOL)

    The aim was to employ artificial intelligence to provide smart triggering pulses for the DVR to mitigate and to provide compensation against voltage sags and swells. The Artificial Neural Network (ANN) was trained online by data gener ated via a 3 - phase programmable voltage generator and these were used as inputs to ...

  5. Process engineering of high voltage alginate encapsulation of mesenchymal stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Gryshkov, Oleksandr, E-mail: gryshkov@imp.uni-hannover.de [Institute for Multiphase Processes, Leibniz University Hannover, D-30167 Hannover (Germany); Pogozhykh, Denys, E-mail: pogozhykh@imp.uni-hannover.de [Institute for Multiphase Processes, Leibniz University Hannover, D-30167 Hannover (Germany); Zernetsch, Holger, E-mail: zernetsch@imp.uni-hannover.de [Institute for Multiphase Processes, Leibniz University Hannover, D-30167 Hannover (Germany); Hofmann, Nicola, E-mail: hofmann@imp.uni-hannover.de [Institute for Multiphase Processes, Leibniz University Hannover, D-30167 Hannover (Germany); Mueller, Thomas, E-mail: mueller.thomas@mh-hannover.de [Institute for Transfusion Medicine, Medical School Hannover, D-30625 Hannover (Germany); Glasmacher, Birgit, E-mail: glasmacher@imp.uni-hannover.de [Institute for Multiphase Processes, Leibniz University Hannover, D-30167 Hannover (Germany)

    2014-03-01

    Encapsulation of stem cells in alginate beads is promising as a sophisticated drug delivery system in treatment of a wide range of acute and chronic diseases. However, common use of air flow encapsulation of cells in alginate beads fails to produce beads with narrow size distribution, intact spherical structure and controllable sizes that can be scaled up. Here we show that high voltage encapsulation (≥ 15 kV) can be used to reproducibly generate spherical alginate beads (200–400 μm) with narrow size distribution (± 5–7%) in a controlled manner under optimized process parameters. Flow rate of alginate solution ranged from 0.5 to 10 ml/h allowed producing alginate beads with a size of 320 and 350 μm respectively, suggesting that this approach can be scaled up. Moreover, we found that applied voltages (15–25 kV) did not alter the viability and proliferation of encapsulated mesenchymal stem cells post-encapsulation and cryopreservation as compared to air flow. We are the first who employed a comparative analysis of electro-spraying and air flow encapsulation to study the effect of high voltage on alginate encapsulated cells. This report provides background in application of high voltage to encapsulate living cells for further medical purposes. Long-term comparison and work on alginate–cell interaction within these structures will be forthcoming. - Highlights: • High voltage alginate encapsulation of mesenchymal stem cells (MSCs) was designed. • Reproducible and spherical alginate beads were generated via high voltage. • Air flow encapsulation was utilized as a comparative approach to high voltage. • High voltage did not alter the viability and proliferation of encapsulated MSCs. • High voltage encapsulation can be scaled up and applied in cell-based therapy.

  6. Integrated differential high-voltage transmitting circuit for CMUTs

    DEFF Research Database (Denmark)

    Llimos Muntal, Pere; Larsen, Dennis Øland; Farch, Kjartan

    2015-01-01

    In this paper an integrated differential high-voltage transmitting circuit for capacitive micromachined ultrasonic transducers (CMUTs) used in portable ultrasound scanners is designed and implemented in a 0.35 μm high-voltage process. Measurements are performed on the integrated circuit in order...... to assess its performance. The circuit generates pulses at differential voltage levels of 60V, 80V and 100 V, a frequency up to 5MHz and a measured driving strength of 1.75 V/ns with the CMUT connected. The total on-chip area occupied by the transmitting circuit is 0.18 mm2 and the power consumption...

  7. Enhanced Model of Nonlinear Spiral High Voltage Divider

    Directory of Open Access Journals (Sweden)

    V. Panko

    2015-04-01

    Full Text Available This paper deals with the enhanced accurate DC and RF model of nonlinear spiral polysilicon voltage divider. The high resistance polysilicon divider is a sensing part of the high voltage start-up MOSFET transistor that can operate up to 700 V. This paper presents the structure of a proposed model, implemented voltage, frequency and temperature dependency, and scalability. A special attention is paid to the ability of the created model to cover the mismatch and influence of a variation of process parameters on the device characteristics. Finally, the comparison of measured data vs. simulation is presented in order to confirm the model validity and a typical application is demonstrated.

  8. Highly-Efficient and Modular Medium-Voltage Converters

    Science.gov (United States)

    2015-09-28

    of the modular multilevel converter based on si and sic switching devices for medium/high-voltage applications," IEEE Trans. Electron Devices, vol...4. TITLE AND SUBTITLE Highly-Efficient and Modula Medium-Voltage Converters 6. AUTHOR(S) Maryam Saeedifard 7. PERFORMING ORGANIZATIC i NAME(S...improving the converter’s efficiency and power density. 15. SUBJECT TERMS Modular Multilevel Converters , DC-DC Conversion, DC-AC Conversion 16

  9. A Half-Bridge Voltage Balancer with New Controller for Bipolar DC Distribution Systems

    Directory of Open Access Journals (Sweden)

    Byung-Moon Han

    2016-03-01

    Full Text Available This paper proposes a half-bridge voltage balancer with a new controller for bipolar DC distribution systems. The proposed control scheme consists of two cascaded Proportional Integral (PI controls rather than one PI control for balancing the pole voltage. In order to confirm the excellence of voltage balancing performance, a typical bipolar DC distribution system including a half-bridge voltage balancer with proposed controller was analyzed by computer simulations. Experiments with a scaled prototype were also carried out to confirm the simulation results. The half-bridge voltage balancer with proposed controller shows better performance than the half-bridge voltage balancer with one PI control for balancing the pole voltage.

  10. Multi-objective optimization control of plug-in electric vehicles in low voltage distribution networks

    DEFF Research Database (Denmark)

    García-Villalobos, J.; Zamora, I.; Knezovic, Katarina

    2016-01-01

    The massive introduction of plug-in electric vehicles (PEVs) into low voltage (LV) distribution networks will lead to several problems, such as: increase of energy losses, decrease of distribution transformer lifetime, lines and transformer overload issues, voltage drops and unbalances. In this c...

  11. High Voltage Bi-directional Flyback Converter for Capacitive Actuator

    DEFF Research Database (Denmark)

    Thummala, Prasanth; Zhang, Zhe; Andersen, Michael A. E.

    2013-01-01

    This paper presents a high voltage DC-DC converter topology for bi-directional energy transfer between a low voltage DC source and a high voltage capacitive load. The topology is a bi-directional flyback converter with variable switching frequency control during the charge mode, and constant...... switching frequency control during the discharge mode. The converter is capable of charging the capacitive load from 24 V DC source to 2.5 kV, and discharges it to 0 V. The flyback converter has been analyzed in detail during both charge and discharge modes, by considering all the parasitic elements...... in the converter, including the most dominating parameters of the high voltage transformer viz., self-capacitance and leakage inductance. The specific capacitive load for this converter is a dielectric electro active polymer (DEAP) actuator, which can be used as an effective replacement for conventional actuators...

  12. High Input Voltage, Silicon Carbide Power Processing Unit Performance Demonstration

    Science.gov (United States)

    Bozak, Karin E.; Pinero, Luis R.; Scheidegger, Robert J.; Aulisio, Michael V.; Gonzalez, Marcelo C.; Birchenough, Arthur G.

    2015-01-01

    A silicon carbide brassboard power processing unit has been developed by the NASA Glenn Research Center in Cleveland, Ohio. The power processing unit operates from two sources: a nominal 300 Volt high voltage input bus and a nominal 28 Volt low voltage input bus. The design of the power processing unit includes four low voltage, low power auxiliary supplies, and two parallel 7.5 kilowatt (kW) discharge power supplies that are capable of providing up to 15 kilowatts of total power at 300 to 500 Volts (V) to the thruster. Additionally, the unit contains a housekeeping supply, high voltage input filter, low voltage input filter, and master control board, such that the complete brassboard unit is capable of operating a 12.5 kilowatt Hall effect thruster. The performance of the unit was characterized under both ambient and thermal vacuum test conditions, and the results demonstrate exceptional performance with full power efficiencies exceeding 97%. The unit was also tested with a 12.5kW Hall effect thruster to verify compatibility and output filter specifications. With space-qualified silicon carbide or similar high voltage, high efficiency power devices, this would provide a design solution to address the need for high power electric propulsion systems.

  13. High Input Voltage, Silicon Carbide Power Processing Unit Performance Demonstration

    Science.gov (United States)

    Bozak, Karin E.; Pinero, Luis R.; Scheidegger, Robert J.; Aulisio, Michael V.; Gonzalez, Marcelo C.; Birchenough, Arthur G.

    2015-01-01

    A silicon carbide brassboard power processing unit has been developed by the NASA Glenn Research Center in Cleveland, Ohio. The power processing unit operates from two sources - a nominal 300-Volt high voltage input bus and a nominal 28-Volt low voltage input bus. The design of the power processing unit includes four low voltage, low power supplies that provide power to the thruster auxiliary supplies, and two parallel 7.5 kilowatt power supplies that are capable of providing up to 15 kilowatts of total power at 300-Volts to 500-Volts to the thruster discharge supply. Additionally, the unit contains a housekeeping supply, high voltage input filter, low voltage input filter, and master control board, such that the complete brassboard unit is capable of operating a 12.5 kilowatt Hall Effect Thruster. The performance of unit was characterized under both ambient and thermal vacuum test conditions, and the results demonstrate the exceptional performance with full power efficiencies exceeding 97. With a space-qualified silicon carbide or similar high voltage, high efficiency power device, this design could evolve into a flight design for future missions that require high power electric propulsion systems.

  14. Planar LTCC transformers for high voltage flyback converters: Part II.

    Energy Technology Data Exchange (ETDEWEB)

    Schofield, Daryl (NASCENTechnology, Inc., Watertown, SD); Schare, Joshua M., Ph.D.; Slama, George (NASCENTechnology, Inc., Watertown, SD); Abel, David (NASCENTechnology, Inc., Watertown, SD)

    2009-02-01

    This paper is a continuation of the work presented in SAND2007-2591 'Planar LTCC Transformers for High Voltage Flyback Converters'. The designs in that SAND report were all based on a ferrite tape/dielectric paste system originally developed by NASCENTechnoloy, Inc, who collaborated in the design and manufacturing of the planar LTCC flyback converters. The output/volume requirements were targeted to DoD application for hard target/mini fuzing at around 1500 V for reasonable primary peak currents. High voltages could be obtained but with considerable higher current. Work had begun on higher voltage systems and is where this report begins. Limits in material properties and processing capabilities show that the state-of-the-art has limited our practical output voltage from such a small part volume. In other words, the technology is currently limited within the allowable funding and interest.

  15. A High-Voltage Test Bed for the Evaluation of High-Voltage Dividers for Pulsed Applications

    CERN Document Server

    Bastos, M C; Hammarquist, M

    2011-01-01

    The design, evaluation, and commissioning of a high-voltage reference test bed for pulsed applications to be used in the precision testing of high-voltage dividers is described. The test bed is composed of a pulsed power supply, a reference divider based on compressed-gas capacitor technology, and an acquisition system that makes use of the fast measurement capabilities of the HP3458 digital voltmeter. The results of the evaluation of the reference system are presented.

  16. On-chip High-Voltage Generator Design

    CERN Document Server

    Tanzawa, Toru

    2013-01-01

    This book describes high-voltage generator design with switched-capacitor multiplier techniques.  The author provides various design techniques for switched-capacitor on-chip high-voltage generators, including charge pump circuits, regulators, level shifters, references, and oscillators.  Readers will see these techniques applied to system design in order to address the challenge of how the on-chip high-voltage generator is designed for Flash memories, LCD drivers, and other semiconductor devices to optimize the entire circuit area and power efficiency with a low voltage supply, while minimizing the cost.   ·         Shows readers how to design charge pump circuits with lower voltage operation, higher power efficiency, and smaller circuit area; ·         Describes comprehensive circuits and systems design of on-chip high-voltage generators; ·         Covers all the component circuit blocks, including charge pumps, pump regulators, level shifters, oscillators, and references.

  17. Reliability and Characterization of High Voltage Power Capacitors

    Science.gov (United States)

    2014-03-01

    permittivity EVCS electric vehicle charging system GPIB general-purpose interface bus GW giga-watt HVST high voltage stress test IV current voltage...traditional fossil fuel . The typical solar power system requires multiple subsystems as well as the physical infrastructure to support the solar panels. The...that will last, reducing the militaries overall dependence on traditional fossil fuel . B. CONVERTER OVERVIEW The typical solar power system

  18. Electric Field Simulations and Analysis for High Voltage High Power Medium Frequency Transformer

    Directory of Open Access Journals (Sweden)

    Pei Huang

    2017-03-01

    Full Text Available The electronic power transformer (EPT raises concerns for its notable size and volume reduction compared with traditional line frequency transformers. Medium frequency transformers (MFTs are important components in high voltage and high power energy conversion systems such as EPTs. High voltage and high power make the reliable insulation design of MFT more difficult. In this paper, the influence of wire type and interleaved winding structure on the electric field distribution of MFT is discussed in detail. The electric field distributions for six kinds of typical non-interleaved windings with different wire types are researched using a 2-D finite element method (FEM. The electric field distributions for one non-interleaved winding and two interleaved windings are also studied using 2-D FEM. Furthermore, the maximum electric field intensities are obtained and compared. The results show that, in this case study, compared with foil conductor, smaller maximum electric field intensity can be achieved using litz wire in secondary winding. Besides, interleaving can increase the maximum electric field intensity when insulation distance is constant. The proposed method of studying the electric field distribution and analysis results are expected to make a contribution to the improvement of electric field distribution in transformers.

  19. Enhancement of Surface Flashover Performance of High Voltage Ceramic Disc Insulators

    Science.gov (United States)

    Subba Reddy, B.; Kumar, Udaya

    2011-02-01

    In this paper, an effort is made to study accurately the field distribution for various types of ceramic insulators used for high-voltage transmission. The surface charge simulation method (SCSM) is employed for the field computation. With the help of SCSM program, a Novel field reduction electrode is designed and developed to reduce the maximum field around the pin region. In order to experimentally analyze the performance of discs with field reduction electrode, special artificial pollution test facility was built and utilized. The experimental results show better surface flashover performance of ceramic insulators used in high-voltage transmission and distribution systems.

  20. Unequal Input Voltages Distribution Between the Serial Connected Halfbridges

    Directory of Open Access Journals (Sweden)

    Radovan Ovcarcik

    2006-01-01

    Full Text Available This paper describes a topology of DC-DC converter consisting in two serial connected half-bridges. Secondary circuit is realized like a conventional full-wave rectifier. The main advantage of this topology is the possibility of dividing the input voltage between the half-bridges. The converter is controlled using the phase-shift modulation, which allows a ZVSoperation mode. The voltage unbalance between the inputs causes an important problem of the presented topology. It is necessary to avoid it by the control algorithm, which is described in the text. The practical results show a zero voltage switching technique and the limits of the chosen topology and of the control.

  1. Fuzzy-driven energy storage system for mitigating voltage unbalance factor on distribution network with photovoltaic system

    Science.gov (United States)

    Wong, Jianhui; Lim, Yun Seng; Morris, Stella; Morris, Ezra; Chua, Kein Huat

    2017-04-01

    The amount of small-scaled renewable energy sources is anticipated to increase on the low-voltage distribution networks for the improvement of energy efficiency and reduction of greenhouse gas emission. The growth of the PV systems on the low-voltage distribution networks can create voltage unbalance, voltage rise, and reverse-power flow. Usually these issues happen with little fluctuation. However, it tends to fluctuate severely as Malaysia is a region with low clear sky index. A large amount of clouds often passes over the country, hence making the solar irradiance to be highly scattered. Therefore, the PV power output fluctuates substantially. These issues can lead to the malfunction of the electronic based equipment, reduction in the network efficiency and improper operation of the power protection system. At the current practice, the amount of PV system installed on the distribution network is constraint by the utility company. As a result, this can limit the reduction of carbon footprint. Therefore, energy storage system is proposed as a solution for these power quality issues. To ensure an effective operation of the distribution network with PV system, a fuzzy control system is developed and implemented to govern the operation of an energy storage system. The fuzzy driven energy storage system is able to mitigate the fluctuating voltage rise and voltage unbalance on the electrical grid by actively manipulates the flow of real power between the grid and the batteries. To verify the effectiveness of the proposed fuzzy driven energy storage system, an experimental network integrated with 7.2kWp PV system was setup. Several case studies are performed to evaluate the response of the proposed solution to mitigate voltage rises, voltage unbalance and reduce the amount of reverse power flow under highly intermittent PV power output.

  2. Stability Boundaries for Offshore Wind Park Distributed Voltage Control

    DEFF Research Database (Denmark)

    Gryning, Mikkel P.S.; Wu, Qiuwei; Kocewiak, Lukasz

    2017-01-01

    In order to identify mechanisms causing slow reactive power oscillations observed in an existing offshore wind power plant, and be able to avoid similar events in the future, voltage control is studied in this paper for a plant with a static synchronous compensator, type-4 wind turbines and a park...... pilot control. Using data from the actual wind power plant, all stabilizing subsystem voltage proportional-integral controller parameters are first characterized based on their Hurwitz signature. Inner loop current control is then designed using Internal Mode Control principles, and guidelines for feed...

  3. DETERMINATION OF ANALYTICAL CALCULATION ERROR OF MAGNETIC FIELD OF HIGH-VOLTAGE CABLE LINES WITH TWO-POINT BONDED CABLE SHIELDS CAUSED BY NON-UNIFORM CURRENT DISTRIBUTION IN THE SHIELDS

    Directory of Open Access Journals (Sweden)

    M. I. Baranov

    2017-06-01

    Full Text Available Purpose. To obtain new calculation correlations, determining approximate energy dissipation and electric erosion of massive basic metallic electrodes in the high-voltage high-current air switchboard (HVCAS of atmospheric pressure, in-use in the bit chain of the high-voltage electrophysics setting (HVES with the powerful capacity store of energy (CSE. Methodology. Electrophysics bases of technique of high-voltage and large impulsive currents (LIC, scientific and technical bases of development and planning of high-voltage heavy-current impulsive electro-devices, including HVES and powerful CSE, and also methods of measuring in their bit chains of LIC of the microsecond temporal range. Results. On the basis of new engineering approach the results of calculation estimation of excretions energy and electric erosion of massive basic metallic electrodes are resulted in probed HVCAS. New correlations are obtained for the approximate calculation of thermal energy, selected in an impulsive air spark and on the workings surfaces of anode and cathode of HVCAS. It is entered and a new electrophysics concept, touching equivalent active resistance of impulsive air spark, is mathematically certain. New formulas are obtained for the approximate calculation of most depth of single round crater of destruction on the workings surfaces of basic metallic electrodes of HVCAS, and also mass of metal, thrown out magnetic pressure from this crater of destruction on the electrodes of switch for one electric discharge through them powerful CSE HVES. It is shown that the radius of the indicated single crater of destruction is approximately equal to the maximal radius of plasma channel of a spark discharge between a cathode and anode of HVCAS. The executed high-current experiments in the bit chain of HVES with powerful CSE validated row of the got and in-use calculation correlations for the estimation of energy dissipation and electric erosion of metallic electrodes in

  4. Statistical characteristics of transient enclosure voltage in ultra-high-voltage gas-insulated switchgear

    Science.gov (United States)

    Cai, Yuanji; Guan, Yonggang; Liu, Weidong

    2017-06-01

    Transient enclosure voltage (TEV), which is a phenomenon induced by the inner dielectric breakdown of SF6 during disconnector operations in a gas-insulated switchgear (GIS), may cause issues relating to shock hazard and electromagnetic interference to secondary equipment. This is a critical factor regarding the electromagnetic compatibility of ultra-high-voltage (UHV) substations. In this paper, the statistical characteristics of TEV at UHV level are collected from field experiments, and are analyzed and compared to those from a repeated strike process. The TEV waveforms during disconnector operations are recorded by a self-developed measurement system first. Then, statistical characteristics, such as the pulse number, duration of pulses, frequency components, magnitude and single pulse duration, are extracted. The transmission line theory is introduced to analyze the TEV and is validated by the experimental results. Finally, the relationship between the TEV and the repeated strike process is analyzed. This proves that the pulse voltage of the TEV is proportional to the corresponding breakdown voltage. The results contribute to the definition of the standard testing waveform of the TEV, and can aid the protection of electronic devices in substations by minimizing the threat of this phenomenon.

  5. Temperature Stabilized Characterization of High Voltage Power Supplies

    CERN Document Server

    Krarup, Ole

    2017-01-01

    High precision measurements of the masses of nuclear ions in the ISOLTRAP experiment relies on an MR-ToF. A major source of noise and drift is the instability of the high voltage power supplies employed. Electrical noise and temperature changes can broaden peaks in time-of-flight spectra and shift the position of peaks between runs. In this report we investigate how the noise and drift of high-voltage power supplies can be characterized. Results indicate that analog power supplies generally have better relative stability than digitally controlled ones, and that the high temperature coefficients of all power supplies merit efforts to stabilize them.

  6. High voltage switch triggered by a laser-photocathode subsystem

    Science.gov (United States)

    Chen, Ping; Lundquist, Martin L.; Yu, David U. L.

    2013-01-08

    A spark gap switch for controlling the output of a high voltage pulse from a high voltage source, for example, a capacitor bank or a pulse forming network, to an external load such as a high gradient electron gun, laser, pulsed power accelerator or wide band radar. The combination of a UV laser and a high vacuum quartz cell, in which a photocathode and an anode are installed, is utilized as triggering devices to switch the spark gap from a non-conducting state to a conducting state with low delay and low jitter.

  7. Short-Term State Forecasting-Based Optimal Voltage Regulation in Distribution Systems: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Rui; Jiang, Huaiguang; Zhang, Yingchen

    2017-05-17

    A novel short-term state forecasting-based optimal power flow (OPF) approach for distribution system voltage regulation is proposed in this paper. An extreme learning machine (ELM) based state forecaster is developed to accurately predict system states (voltage magnitudes and angles) in the near future. Based on the forecast system states, a dynamically weighted three-phase AC OPF problem is formulated to minimize the voltage violations with higher penalization on buses which are forecast to have higher voltage violations in the near future. By solving the proposed OPF problem, the controllable resources in the system are optimally coordinated to alleviate the potential severe voltage violations and improve the overall voltage profile. The proposed approach has been tested in a 12-bus distribution system and simulation results are presented to demonstrate the performance of the proposed approach.

  8. High-Voltage Converter for the Traction Application

    Directory of Open Access Journals (Sweden)

    Sergey Volskiy

    2016-01-01

    Full Text Available High-voltage converter employing IGCT switches (VDC=2800 V for traction application is presented. Such a power traction drive operates with an unstable input voltage over 2000⋯4000 V DC and with an output power up to 1200 kW. The original power circuit of the high-voltage converter is demonstrated. Development of the attractive approach to designing the low-loss snubber circuits of the high-frequency IGCT switches is proposed. It is established on the complex multilevel analysis of the transient phenomena and power losses. The essential characteristics of the critical parameters under transient modes and the relation between the snubber circuit parameters and the losses are discussed. Experimental results for the prototype demonstrate the properties of new power circuit. The test results confirm the proposed high-voltage converter performance capability as well as verifying the suitability of the conception for its use in the Russian suburban train power system and other high-voltage applications.

  9. An Improved Voltage Regulation of a Distribution Network Using ...

    African Journals Online (AJOL)

    The Newton-Raphson Load flow equation modeling was a veritable tool applied in this analysis to determine the convergence points for the voltage magnitude, power (load) angle, power losses along the lines, sending end and receiving end power values at the various buses that make up the thirteen bus network.

  10. High-Capacity, High-Voltage Composite Oxide Cathode Materials

    Science.gov (United States)

    Hagh, Nader M.

    2015-01-01

    This SBIR project integrates theoretical and experimental work to enable a new generation of high-capacity, high-voltage cathode materials that will lead to high-performance, robust energy storage systems. At low operating temperatures, commercially available electrode materials for lithium-ion (Li-ion) batteries do not meet energy and power requirements for NASA's planned exploration activities. NEI Corporation, in partnership with the University of California, San Diego, has developed layered composite cathode materials that increase power and energy densities at temperatures as low as 0 degC and considerably reduce the overall volume and weight of battery packs. In Phase I of the project, through innovations in the structure and morphology of composite electrode particles, the partners successfully demonstrated an energy density exceeding 1,000 Wh/kg at 4 V at room temperature. In Phase II, the team enhanced the kinetics of Li-ion transport and electronic conductivity at 0 degC. An important feature of the composite cathode is that it has at least two components that are structurally integrated. The layered material is electrochemically inactive; however, upon structural integration with a spinel material, the layered material can be electrochemically activated and deliver a large amount of energy with stable cycling.

  11. E-beam high voltage switching power supply

    Science.gov (United States)

    Shimer, Daniel W.; Lange, Arnold C.

    1997-01-01

    A high power, solid state power supply is described for producing a controllable, constant high voltage output under varying and arcing loads suitable for powering an electron beam gun or other ion source. The present power supply is most useful for outputs in a range of about 100-400 kW or more. The power supply is comprised of a plurality of discrete switching type dc-dc converter modules, each comprising a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, and an output rectifier for producing a dc voltage at the output of each module. The inputs to the converter modules are fed from a common dc rectifier/filter and are linked together in parallel through decoupling networks to suppress high frequency input interactions. The outputs of the converter modules are linked together in series and connected to the input of the transmission line to the load through a decoupling and line matching network. The dc-dc converter modules are phase activated such that for n modules, each module is activated equally 360.degree./n out of phase with respect to a successive module. The phased activation of the converter modules, combined with the square current waveforms out of the step up transformers, allows the power supply to operate with greatly reduced output capacitance values which minimizes the stored energy available for discharge into an electron beam gun or the like during arcing. The present power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle using simulated voltage feedback signals and voltage feedback loops. Circuitry is also provided for sensing incipient arc currents reflected at the output of the power supply and for simultaneously decoupling the power supply circuitry from the arcing load.

  12. Gaseous insulators for high voltage electrical equipment

    Science.gov (United States)

    Christophorou, Loucas G.; James, David R.; Pace, Marshall O.; Pai, Robert Y.

    1979-01-01

    Gaseous insulators comprise compounds having high attachment cross sections for electrons having energies in the 0-1.3 electron volt range. Multi-component gaseous insulators comprise compounds and mixtures having overall high electron attachment cross sections in the 0-1.3 electron volt range and moderating gases having high cross sections for inelastic interactions with electrons of energies 1-4 electron volts. Suitable electron attachment components include hexafluorobutyne, perfluorobutene-2, perfluorocyclobutane, perfluorodimethylcyclobutane, perfluorocyclohexene, perfluoromethylcyclohexane, hexafluorobutadiene, perfluoroheptene-1 and hexafluoroazomethane. Suitable moderating gases include N.sub.2, CO, CO.sub.2 and H.sub.2. The gaseous insulating mixture can also contain SF.sub.6, perfluoropropane and perfluorobenzene.

  13. Modeling of long High Voltage AC Underground

    DEFF Research Database (Denmark)

    Gudmundsdottir, Unnur Stella; Bak, Claus Leth; Wiechowski, W. T.

    2010-01-01

    cable models, perform highly accurate field measurements for validating the model and identifying possible disadvantages of the cable model. Furthermore the project suggests and implements improvements and validates them against several field measurements. It is shown in this paper how a new method...

  14. Potential distribution on stress grading of inverter-fed rotating machines under DC biased voltage

    Directory of Open Access Journals (Sweden)

    Takahiro Nakamura

    2016-01-01

    Full Text Available The erosion of the stress grading system of converter-fed rotating machines may occur by partial discharges and heat generation. There remain unclear issues in the formation of the potential and temperature distributions along the stress grading system of coils. In this paper, the potential distributions on the stress grading system of the model coil bar are measured under the application of 1 kHz square wave voltages of 10 kV in peak to peak value with/without 5 kV DC biased voltage. It turns out that DC bias voltage has little effect on potential distribution on a coil surface.

  15. Power capability in low voltage dc distribution systems

    National Research Council Canada - National Science Library

    CO Gecan; Chindris; R Bindiu

    2009-01-01

    ... a LVDC distribution system. The paper presents some general considerations regarding cables used in a LVAC distribution system and different line reconfigurations witch enable the use of cobles in a LVDC distribution system...

  16. Reconnection of the islanded portion of the CIGRE low voltage distribution network

    DEFF Research Database (Denmark)

    Bhutto, G.M.; Bak, Claus Leth; Somro, Duur M.

    2016-01-01

    is less as compared to that of the grid connected system. The islanded portion of the distribution network can be reconnected to the transmission grid if the voltage magnitudes, voltage phase angles and the frequencies of the two systems are synchronized. The main objective of this paper is to facilitate...

  17. High-Voltage Multiplexing for ATLAS ITk

    CERN Document Server

    Hommels, Bart; The ATLAS collaboration

    2017-01-01

    The High Luminosity upgrade to the Large Hadron Collider (HL-LHC) requires a replacement of the present ATLAS inner tracker with an all-silicon inner tracker (ITk). The outer radii of the ITk will consist of groups of silicon strip sensors mounted on common support structures. Lack of space for additional cabling will require groups of sensors to share a common HV bus (-500 V). This creates a need to remotely disable a failing sensor from the common HV bus to permit continued operation of the other sensors. We have developed circuitry consisting of a Gallium Nitride Field-Effect transistor (GaNFET) and a HV Multiplier circuit to disable a failed sensor. The devices have been shown to survive radiation doses as high as 1 x 1016 neutrons/cm2 and ionizing doses over 200 Mrad. We will present the HV Mux circuitry and show irradiation results on individual components with an emphasis on the GaNFET results with neutrons, protons, pions, and gammas. We will present a dual-stage variation of the HV Mux that will perm...

  18. A flexible low-voltage ride-through operation for the distributed generation converters

    DEFF Research Database (Denmark)

    Chen, Hsin-Chih; Lee, Chia-Tse; Cheng, Po-Tai

    2013-01-01

    With more and more distributed energy resources (DERs) are installed in the utility grid, the utility requires the DER generation system to remain grid-connected and injects reactive and active power to support grid voltage during voltage sags. In this paper, a positive- and negative......-sequence current injection method is proposed to meet the low-voltage ride through (LVRT) requirement. The proposed method predefined a current constraint to avoid the overcurrent during the LVRT operation and adjust the positive-sequence reactive current to reduce the DC-bus voltage ripple. Comparisons...

  19. High voltage pulsed cable design: a practical example

    Energy Technology Data Exchange (ETDEWEB)

    Kewish, R.W. Jr.; Boicourt, G.P.

    1979-01-01

    The design of optimum high voltage pulse cable is difficult because very little emperical data are available on performance in pulsed applications. This paper follows the design and testing of one high voltage pulse cable, 40/100 trigger cable. The design was based on an unproven theory and the impressive outcome lends support to the theory. The theory is outlined and it is shown that there exists an inductance which gives a cable of minimum size for a given maximum stress. Test results on cable manufactured according to the design are presented and compared with the test results on the cable that 40/100 replaces.

  20. Ultra High Voltage Surge Waveforms Measurement Using an Optical Transducer

    Directory of Open Access Journals (Sweden)

    Francisco G. PEÑA-LECONA

    2010-05-01

    Full Text Available Ultra high voltage surge waveforms measurement by means of a portable optical transducer is presented. The sensor system uses a transducer element based on the longitudinal electro-optic effect with a double pass configuration to obtain a better sensitivity. The transducer head is allocated to one meter of distance from the generating element of electric field and it is able to measure waveform surges from 515 kV up to 1090 kV with fast response. It is demonstrated that the telemetry of ultra high voltage surge waveforms can be successfully done by means of this proposed optical transducer.

  1. Digitally gain controlled linear high voltage amplifier for laboratory applications

    Science.gov (United States)

    Koçum, C.

    2011-08-01

    The design of a digitally gain controlled high-voltage non-inverting bipolar linear amplifier is presented. This cost efficient and relatively simple circuit has stable operation range from dc to 90 kHz under the load of 10 kΩ and 39 pF. The amplifier can swing up to 360 Vpp under these conditions and it has 2.5 μs rise time. The gain can be changed by the aid of JFETs. The amplifiers have been realized using a combination of operational amplifiers and high-voltage discrete bipolar junction transistors. The circuit details and performance characteristics are discussed.

  2. The research of high voltage switchgear detecting unit

    Science.gov (United States)

    Ji, Tong; Xie, Wei; Wang, Xiaoqing; Zhang, Jinbo

    2017-07-01

    In order to understand the status of the high voltage switch in the whole life circle, you must monitor the mechanical and electrical parameters that affect device health. So this paper gives a new high voltage switchgear detecting unit based on ARM technology. It can measure closing-opening mechanical wave, storage motor current wave and contactor temperature to judge the device’s health status. When something goes wrong, it can be on alert and give some advice. The practice showed that it can meet the requirements of circuit breaker mechanical properties temperature online detection.

  3. High-voltage, high-current, solid-state closing switch

    Energy Technology Data Exchange (ETDEWEB)

    Focia, Ronald Jeffrey

    2017-08-22

    A high-voltage, high-current, solid-state closing switch uses a field-effect transistor (e.g., a MOSFET) to trigger a high-voltage stack of thyristors. The switch can have a high hold-off voltage, high current carrying capacity, and high time-rate-of-change of current, di/dt. The fast closing switch can be used in pulsed power applications.

  4. Diagnosis of High Voltage Insulators Made of Ceramic Using Spectrophotometry

    Directory of Open Access Journals (Sweden)

    Paweł Frącz

    2016-01-01

    Full Text Available The paper presents results of comparative analysis of optical signals emitted by partial discharges occurring on three types of high voltage insulators made of porcelain. The research work consisted of diagnosis of the following devices: a long rod insulator, a cap insulator, and an insulating cylinder. For optical signal registration a spectrophotometer was applied. All measurements were performed under laboratory conditions by changing the value of partial discharges generation voltage. For the cylindrical insulator also the distance between high voltage and ground electrodes was subjected for investigation as a factor having influence on partial discharges. The main contribution which resulted from the studies is statement that application of spectrophotometer enables faster recognition of partial discharges, as compared to standard methods.

  5. Digitally Programmable High-Q Voltage Mode Universal Filter

    Directory of Open Access Journals (Sweden)

    D. Singh

    2013-12-01

    Full Text Available A new low-voltage low-power CMOS current feedback amplifier (CFA is presented in this paper. This is used to realize a novel digitally programmable CFA (DPCFA using transistor arrays and MOS switches. The proposed realizations nearly allow rail-to-rail swing capability at all the ports. Class-AB output stage ensures low power dissipation and high current drive capability. The proposed CFA/ DPCFA operates at supply voltage of ±0.75 V and exhibits bandwidth better than 95 MHz. An application of the DPCFA to realize a novel voltage mode high-Q digitally programmable universal filter (UF is given. Performances of all the proposed circuits are verified by PSPICE simulation using TSMC 0.25μm technology parameters.

  6. Architecture, Voltage, and Components for a Turboelectric Distributed Propulsion Electric Grid

    Science.gov (United States)

    Armstrong, Michael J.; Blackwelder, Mark; Bollman, Andrew; Ross, Christine; Campbell, Angela; Jones, Catherine; Norman, Patrick

    2015-01-01

    The development of a wholly superconducting turboelectric distributed propulsion system presents unique opportunities for the aerospace industry. However, this transition from normally conducting systems to superconducting systems significantly increases the equipment complexity necessary to manage the electrical power systems. Due to the low technology readiness level (TRL) nature of all components and systems, current Turboelectric Distributed Propulsion (TeDP) technology developments are driven by an ambiguous set of system-level electrical integration standards for an airborne microgrid system (Figure 1). While multiple decades' worth of advancements are still required for concept realization, current system-level studies are necessary to focus the technology development, target specific technological shortcomings, and enable accurate prediction of concept feasibility and viability. An understanding of the performance sensitivity to operating voltages and an early definition of advantageous voltage regulation standards for unconventional airborne microgrids will allow for more accurate targeting of technology development. Propulsive power-rated microgrid systems necessitate the introduction of new aircraft distribution system voltage standards. All protection, distribution, control, power conversion, generation, and cryocooling equipment are affected by voltage regulation standards. Information on the desired operating voltage and voltage regulation is required to determine nominal and maximum currents for sizing distribution and fault isolation equipment, developing machine topologies and machine controls, and the physical attributes of all component shielding and insulation. Voltage impacts many components and system performance.

  7. High-voltage discharge in supersonic jet of plumbum vapor

    Science.gov (United States)

    Amirov, R. Kh; Antonov, N. N.; Liziakin, G. D.; Polistchook, V. P.; Samoylov, I. S.; Usmanov, R. A.; Yartsev, I. M.

    2015-11-01

    During study of vacuum discharge in plumbum evaporating from molybdenum crucible in identical geometry of discharge gap and the same crucible temperature existence of two different discharge forms were observed. These two forms are vacuum arc with current above 10 A and voltage about 15 V and high-voltage discharge with current about 10 mA and voltage of 340 V. Plumbum was placed in heat-isolated crucible (cathode). Electron-beam heater was situated under the crucible. At the temperature of 1.25 kK that corresponds to plumbum saturated vapor pressure about 0.1 kPa voltage from power source (380 V, 200 A) was applied to anode and high-voltage discharge initiated with characteristics mentioned above. After a few seconds this discharge could turn into arc or could exist hundreds of seconds until total plumbum evaporation. Glow of discharge could take the form of a cone, harness or plasma bunch that hanged at the appreciable distance from the electrodes. The estimations of plasma parameters are presented.

  8. Overhead high-voltage lines - a electromagnetic environment restrictions on use areas

    Directory of Open Access Journals (Sweden)

    Jacek Paś

    2014-09-01

    Full Text Available The paper presents the influence of exploitation of high voltage overhead lines in the vicinity of the lands that are intended for built-up areas. Near distribution stations and high voltage overhead lines can be present some physical and chemical factors which under certain conditions and at their high levels will be inconvenient to the environment. The environmental impacts of these factors are complex problems which are analysed both in technical and biological-medical aspects. [b]Keywords[/b]: overhead lines, electric field and magnetic, lines of force

  9. Design of high voltage DC power supply based on LCC resonant converter

    Science.gov (United States)

    Wang, Z. Q.; Liu, Z. G.; Wang, J. J.; Li, G. F.

    2013-03-01

    The aim of this paper is to design a small size, light weight high frequency high voltage (HFHV) power supply. It presents a comprehensive procedure for designing a high output voltage power supply based on series-parallel (LCC) resonant converter, aiming to realize the soft-switching. Through mathematical calculation based on an extensive of the first harmonic analysis, the paper derives the approach of determining the resonant parameters of the LCC converter. Then, a 35 kV power supply featuring a series-parallel resonant converter topology to compensate the distributed parameter is built to verify the correctness of the theory.

  10. Game Changing Usage of High-Voltage Power Transmission Systems as Extremely Large Antennas for Space Physical and Geophysical Remote Imaging Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Geomagnetic storms drive geomagnetically induced currents (GIC) in high-voltage power transmission systems worldwide. GIC distribution in the transmission system is...

  11. High impulse voltage and current measurement techniques fundamentals, measuring instruments, measuring methods

    CERN Document Server

    Schon, Klaus

    2013-01-01

    Equipment to be installed in electric power-transmission and distribution systems must pass acceptance tests with standardized high-voltage or high-current test impulses which simulate the stress on the insulation caused by external lightning discharges and switching operations in the grid. High impulse voltages and currents are also used in many other fields of science and engineering for various applications. Therefore, precise impulse-measurement techniques are necessary, either to prevent an over- or understressing of the insulation or to guarantee the effectiveness and quality of the application. The book deals with: principal generator circuits for generating high-voltage and high-current impulses measuring systems and their calibration according to IEC 60060 and IEC 62475 methods of estimating uncertainties of measurement mathematical and experimental basis for characterizing the transfer behavior of spatially extended systems used for measuring fast transients. This book is intended for engineers and ...

  12. High-Voltage LED Light Engine with Integrated Driver

    Energy Technology Data Exchange (ETDEWEB)

    Soer, Wouter [Lumileds LLC, San Jose, CA (United States)

    2016-02-29

    LED luminaires have seen dramatic changes in cost breakdown over the past few years. The LED component cost, which until recently was the dominant portion of luminaire cost, has fallen to a level of the same order as the other luminaire components, such as the driver, housing, optics etc. With the current state of the technology, further luminaire performance improvement and cost reduction is realized most effectively by optimization of the whole system, rather than a single component. This project focuses on improving the integration between LEDs and drivers. Lumileds has developed a light engine platform based on low-cost high-power LEDs and driver topologies optimized for integration with these LEDs on a single substrate. The integration of driver and LEDs enables an estimated luminaire cost reduction of about 25% for targeted applications, mostly due to significant reductions in driver and housing cost. The high-power LEDs are based on Lumileds’ patterned sapphire substrate flip-chip (PSS-FC) technology, affording reduced die fabrication and packaging cost compared to existing technology. Two general versions of PSS-FC die were developed in order to create the desired voltage and flux increments for driver integration: (i) small single-junction die (0.5 mm2), optimal for distributed lighting applications, and (ii) larger multi-junction die (2 mm2 and 4 mm2) for high-power directional applications. Two driver topologies were developed: a tapped linear driver topology and a single-stage switch-mode topology, taking advantage of the flexible voltage configurations of the new PSS-FC die and the simplification opportunities enabled by integration of LEDs and driver on the same board. A prototype light engine was developed for an outdoor “core module” application based on the multi-junction PSS-FC die and the single-stage switch-mode driver. The light engine meets the project efficacy target of 128 lm/W at a luminous flux

  13. Design of Plasma Generator Driven by High-frequency High-voltage Power Supply

    OpenAIRE

    Yong-Nong, C.; K. Chih-Ming

    2013-01-01

    In this research, a high-frequency high-voltage power supply designed for plasma generator is presented. The power supply mainly consists of a series resonant converter with a high-frequency high-voltage boost transformer. Due to the indispensable high-voltage inheritance in the operation of plasma generator, the analysis of transformer need considering not only winding resistance, leakage inductance, magnetizing inductance, and core-loss resistance, but also parasitic capacitance resulted fr...

  14. Ultra-compact Marx-type high-voltage generator

    Science.gov (United States)

    Goerz, David A.; Wilson, Michael J.

    2000-01-01

    An ultra-compact Marx-type high-voltage generator includes individual high-performance components that are closely coupled and integrated into an extremely compact assembly. In one embodiment, a repetitively-switched, ultra-compact Marx generator includes low-profile, annular-shaped, high-voltage, ceramic capacitors with contoured edges and coplanar extended electrodes used for primary energy storage; low-profile, low-inductance, high-voltage, pressurized gas switches with compact gas envelopes suitably designed to be integrated with the annular capacitors; feed-forward, high-voltage, ceramic capacitors attached across successive switch-capacitor-switch stages to couple the necessary energy forward to sufficiently overvoltage the spark gap of the next in-line switch; optimally shaped electrodes and insulator surfaces to reduce electric field stresses in the weakest regions where dissimilar materials meet, and to spread the fields more evenly throughout the dielectric materials, allowing them to operate closer to their intrinsic breakdown levels; and uses manufacturing and assembly methods to integrate the capacitors and switches into stages that can be arranged into a low-profile Marx generator.

  15. Nanoscopic voltage distribution of operating cascade laser devices in cryogenic temperature.

    Science.gov (United States)

    Dhar, R S; Ban, D

    2016-06-01

    A nanoscopic exploratory measurement technique to measure voltage distribution across an operating semiconductor device in cryogenic temperature has been developed and established. The cross-section surface of the terahertz (THz) quantum cascade laser (QCL) has been measured that resolves the voltage distribution at nanometer scales. The electric field dissemination across the active region of the device has been attained under the device's lasing conditions at cryogenic temperature of 77 K. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

  16. Special features of large-size resistors for high-voltage pulsed installations

    Science.gov (United States)

    Minakova, N. N.; Ushakov, V. Ya.

    2017-12-01

    Many structural materials in pulsed power engineering operate under extreme conditions. For example, in high-voltage electrophysical installations among which there are multistage high-voltage pulse generators (HVPG), rigid requirements are imposed on characteristics of solid-state resistors that are more promising in comparison with widely used liquid resistors. Materials of such resistors shall be able to withstand strong electric fields, operate at elevated temperatures, in transformer oil, etc. Effective charge of high-voltage capacitors distributed over the HVPG steps (levels) requires uniform voltage distribution along the steps of the installation that can be obtained using large-size resistors. For such applications, polymer composite materials are considered rather promising. They can work in transformer oil and have small mass in comparison with bulky resistors on inorganic basis. This allows technical solutions already developed and implemented in HVPG with liquid resistors to be employed. This paper is devoted to the solution of some tasks related to the application of filled polymers in high-voltage engineering.

  17. Integration of 100% heat pumps and electric vehicles in the low voltage distribution network: A Danish case story

    DEFF Research Database (Denmark)

    Shao, Nan; You, Shi; Segerberg, Helena

    2013-01-01

    The existing electricity infrastructure may to a great extent limit a high penetration of micro-sized Distributed Energy Rescores (DERs), due to physical bottlenecks, e.g. load capacities of cables and transformers and voltage limitations. In this study, integration impacts of heat pumps (HPs...

  18. Study of a High Voltage Ion Engine Power Supply

    Science.gov (United States)

    Stuart, Thomas A.; King, Roger J.; Mayer, Eric

    1996-01-01

    A complete laboratory breadboard version of a ion engine power converter was built and tested. This prototype operated on a line voltage of 80-120 Vdc, and provided output ratings of 1100 V at 1.8 kW, and 250 V at 20 mA. The high-voltage (HV) output voltage rating was revised from the original value of 1350 V at the beginning of the project. The LV output was designed to hold up during a 1-A surge current lasting up to 1 second. The prototype power converter included a internal housekeeping power supply which also operated from the line input. The power consumed in housekeeping was included in the overall energy budget presented for the ion engine converter. HV and LV output voltage setpoints were commanded through potentiometers. The HV converter itself reached its highest power efficiency of slightly over 93% at low line and maximum output. This would dip below 90% at high line. The no-load (rated output voltages, zero load current) power consumption of the entire system was less than 13 W. A careful loss breakdown shows that converter losses are predominately Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET) conduction losses and HV rectifier snubbing losses, with the rectifier snubbing losses becoming predominant at high line. This suggests that further improvements in power efficiency could best be obtained by either developing a rectifier that was adequately protected against voltage overshoot with less snubbing, or by developing a pre-regulator to reduced the range of line voltage on the converter. The transient testing showed the converter to be fully protected against load faults, including a direct short-circuit from the HV output to the LV output terminals. Two currents sensors were used: one to directly detect any core ratcheting on the output transformer and re-initiate a soft start, and the other to directly detect a load fault and quickly shut down the converter for load protection. The finished converter has been extensively fault tested

  19. Digital measurement system for the LHC klystron high voltage modulator.

    CERN Document Server

    Mikkelsen, Anders

    Accelerating voltage in the Large Hadron Collider (LHC) is created by a means of 16 superconducting standing wave RF cavities, each fed by a 400MHz/300kW continuous wave klystron amplifier. Part of the upgrade program for the LHC long shutdown one is to replace the obsolete analogue current and voltage measurement circuitry located in the high voltage bunkers by a new, digital system, using ADCs and optical fibres. A digital measurement card is implemented and integrated into the current HV modulator oil tank (floating at -58kV) and interfaced to the existing digital VME boards collecting the data for several klystrons at the ground potential. Measured signals are stored for the logging, diagnostics and post-mortem analysis purposes.

  20. A new high-voltage interconnection shielding method for SOI monolithic ICs

    Science.gov (United States)

    Zhang, Long; Zhu, Jing; Sun, Weifeng; Huang, Xuequan; Zhao, Minna; Chen, Jiajun; Shi, Longxing; Chen, Jian; Ding, Desheng

    2017-07-01

    The high-voltage interconnection (HVI) issue becomes severe in the high-voltage monolithic ICs when single-layer metal is used for lowering the cost. This paper proposes a dual deep-oxide trenches (DDOT) structure for 500 V Silicon-on-Insulator Lateral Insulated Gate Bipolar Transistor (SOI-LIGBT) to shield the influence of HVI on the breakdown voltage. Compared with the conventional DDOT structure, HVI region of the proposed DDOT structure is shrunk by employing a shallow trench (T1) and a deep trench (T2). Besides the breakdown mechanism in the off-state, the current density and impact ionization rate distributions in the on-state of the proposed structure are also investigated. The experiments demonstrate that the proposed DDOT structure can fully shield the influence of HVI with significant reduction in the area of silicon region beneath the HVI. With almost the same off-state breakdown voltage (BVoff) of 550 V as the conventional DDOT structure, the length of the silicon region under the HVI in the proposed structure is shortened from 45 μm to 15 μm. Meanwhile, no on-state breakdown voltage (BVon) degradation is observed according to the measured results. The new method proposed in this work can also be used for other types of high-voltage devices such as LDMOS and free-wheeling diode in SOI Monolithic ICs.

  1. Proximity effects of high voltage electric power transmission lines on ...

    African Journals Online (AJOL)

    Yomi

    Zeki Demir. Department of Landscape Architecture, Faculty of Forestry, Düzce University. Konuralp, 81620 Düzce, Turkey. E-mail: zekidemir@duzce.edu.tr. Tel: +90-380-5421136. Fax: +90-380-5421136. Accepted 18 August, 2010. The proximity effects of high voltage electric power transmission lines on Leyland Cypress.

  2. A Review of High Voltage Drive Amplifiers for Capacitive Actuators

    DEFF Research Database (Denmark)

    Huang, Lina; Zhang, Zhe; Andersen, Michael A. E.

    2012-01-01

    This paper gives an overview of the high voltage amplifiers, which are used to drive capacitive actuators. The amplifiers for both piezoelectric and DEAP (dielectric electroactive polymer) actuator are discussed. The suitable topologies for driving capacitive actuators are illustrated in detail...

  3. High Voltage Electrical Injuries In The University Of Calabar ...

    African Journals Online (AJOL)

    Background: Burn injuries are a common presentation in Nigerian hospitals and result from a variety of causes. Recently, many have resulted from Petroleum related fire incidents. High voltage electrical injuries are relatively rare; lightning strikes even rarer. In traditional societies where Traditional medicine practitioners are ...

  4. Proximity effects of high voltage electric power transmission lines on ...

    African Journals Online (AJOL)

    The proximity effects of high voltage electric power transmission lines on Leyland Cypress (xCupressocyparis leylandii (Dallim. and A.B. Jacks.) Dallim) and Japanese Privet (Ligustrum japonicum Thunb.) growth were examined in a private nursery located in Sakarya, Turkey. Five transect were randomly chosen in both ...

  5. Pulsed high voltage discharge induce hematologic changes | El ...

    African Journals Online (AJOL)

    The aim of this work to examine the effect of the gas-liquid hybrid discharge treatment system on some hematological parameters. The gas-liquid hybrid discharge (HD) reactor consists of high voltage point discharge electrode above blood surface and cylinderical ground copper electrode containing the blood (in the same ...

  6. 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)

  7. 30 CFR 18.53 - High-voltage longwall mining systems.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage longwall mining systems. 18.53... and Design Requirements § 18.53 High-voltage longwall mining systems. (a) In each high-voltage motor-starter enclosure, with the exception of a controller on a high-voltage shearer, the disconnect device...

  8. Integrating Multi-Domain Distributed Energy Systems with Electric Vehicle PQ Flexibility: Optimal Design and Operation Scheduling for Sustainable Low-Voltage Distribution Grids

    DEFF Research Database (Denmark)

    Morvaj, Boran; Knezovic, Katarina; Evins, Ralph

    2016-01-01

    Electricity and transport sectors have to be decarbonised in order to mitigate climate change effects leading to increased penetration of distributed energy systems (DES) and electric vehicles (EV) which can threaten the security of distribution grid operation. Proper design and operation...... in the stable operation. The model was applied to a real low-voltage Danish distribution grid where measurement data is available on hourly basis in order to determine EV flexibility impacts on carbon emissions, as well as the benefits of optimal DES design. The influence of EV reactive power control...... for minimising carbon emission in low-voltage distribution grids with high share of distributed energy resources and electric vehicles. The framework determines optimal EV flexibility usage (both active and reactive) while satisfying electric and thermal building demands, and maintaining the distribution grid...

  9. Experimental observation of high-voltage, low-current vacuum arcs

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, R.Y.; Puzanov, S.V.; Yashnov, Y.M. [Scientific-Research Inst. Titan, Moscow (Russian Federation)

    1995-12-01

    A poorly explored type of discharge has been investigated in high vacuum (10{sup {minus}7} to 10{sup {minus}6} torr), with a DC high voltage across 0.2- to 0.8-mm gaps. The discharge has been found to be quite different from other widely known types of vacuum and gas discharges by the combination of its voltage-current characteristics (hyperbola-type), source and carriers of current (mostly electrons), and spatial potential distribution (a considerable electric field across the gap and a steep potential fall near the cathode).

  10. Optimal coordinated voltage control in active distribution networks using backtracking search algorithm.

    Science.gov (United States)

    Tengku Hashim, Tengku Juhana; Mohamed, Azah

    2017-01-01

    The growing interest in distributed generation (DG) in recent years has led to a number of generators connected to a distribution system. The integration of DGs in a distribution system has resulted in a network known as active distribution network due to the existence of bidirectional power flow in the system. Voltage rise issue is one of the predominantly important technical issues to be addressed when DGs exist in an active distribution network. This paper presents the application of the backtracking search algorithm (BSA), which is relatively new optimisation technique to determine the optimal settings of coordinated voltage control in a distribution system. The coordinated voltage control considers power factor, on-load tap-changer and generation curtailment control to manage voltage rise issue. A multi-objective function is formulated to minimise total losses and voltage deviation in a distribution system. The proposed BSA is compared with that of particle swarm optimisation (PSO) so as to evaluate its effectiveness in determining the optimal settings of power factor, tap-changer and percentage active power generation to be curtailed. The load flow algorithm from MATPOWER is integrated in the MATLAB environment to solve the multi-objective optimisation problem. Both the BSA and PSO optimisation techniques have been tested on a radial 13-bus distribution system and the results show that the BSA performs better than PSO by providing better fitness value and convergence rate.

  11. An Optimized Reactive Power Control of Distributed Solar Inverters in Low Voltage Networks

    DEFF Research Database (Denmark)

    Demirok, Erhan; Sera, Dezso; Teodorescu, Remus

    2011-01-01

    This study examines the reactive power ancillary services of solar inverters which are connected to low voltage (LV) distribution networks by giving attention to the grid voltage support service and grid losses. Two typical reference LV distribution network models as suburban and farm...... are introduced from the literature in order to evaluate contribution of two static droop strategies cosφ(P) and Q(U) on the grid voltage. Photovoltaic (PV) hosting capacities of the suburban and farm networks are estimated and the most predominant limitations of connecting more solar inverters are emphasized...... for each network type. Regarding the overloading of MV/LV distribution transformers, overloading of lines and the grid overvoltage limitations, new local grid voltage support methods (cosφ(P,U) and Q(U,P)) are also proposed. Resulting maximum allowable penetration levels with different reactive power...

  12. Secondary Frequency and Voltage Control of Islanded Microgrids via Distributed Averaging

    DEFF Research Database (Denmark)

    W. Simpson-Porco, John; Shafiee, Qobad; Dorfler, Florian

    2015-01-01

    actions. The frequency controller rapidly regulates the microgrid frequency to its nominal value while maintaining active power sharing among the distributed generators. Tuning of the voltage controller provides a simple and intuitive trade-off between the conflicting goals of voltage regulation......In this work we present new distributed controllers for secondary frequency and voltage control in islanded microgrids. Inspired by techniques from cooperative control, the proposed controllers use localized information and nearest neighbour communication to collectively perform secondary control...... and reactive power sharing. Our designs require no knowledge of the microgrid topology, impedances or loads. The distributed architecture allows for flexibility and redundancy, and eliminates the need for a central microgrid controller. We provide a voltage stability analysis and present extensive experimental...

  13. Control of total voltage in the large distributed RF system of LEP

    CERN Document Server

    Ciapala, Edmond

    1995-01-01

    The LEP RF system is made up of a large number of independent RF units situated around the ring near the interaction points. These have different available RF voltages depending on their type and they may be inactive or unable to provide full voltage for certain periods. The original RF voltage control system was based on local RF unit voltage function generators pre-loaded with individual tables for energy ramping. This was replaced this year by a more flexible global RF voltage control system. A central controller in the main control room has direct access to the units over the LEP TDM system via multiplexers and local serial links. It continuously checks the state of all the units and adjusts their voltages to maintain the desired total voltage under all conditions. This voltage is distributed among the individual units to reduce the adverse effects of RF voltage asymmetry around the machine as far as possible. The central controller is a VME system with 68040 CPU and real time multitasking operating syste...

  14. Surges in low voltage distribution networks: some of conducted studies; Surtos em redes de baixa tensao: alguns estudos realizados

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-04-01

    This article presents an experience conducted by the Brazilian CELESC - Centrais Electricas de Santa Catarina, by installing two low voltage Si C lightning rods, one near of a batch of distribution transformers, and the other in the protection and measurement cabinet. That installation considered the high number of damages in transformers and meters in a region where 118 days of storm are detected. For the study, two regions presented similar climate characteristics and high number of damaged equipment. The low voltage lightning rods were installed only in one of the regions.

  15. Design and development of high voltage high power operational ...

    Indian Academy of Sciences (India)

    Normally power opamps can deliver current more than 50 mA and can operate on the supply voltage more than ±25 V. This paper gives the details of one of the power opamps developed to drive the Piezo Actuators for Active Vibration Control (AVC) of aircraft/aerospace structures. The designed power opamp will work on ...

  16. Voltage and frequency control in the Islanded portion of the CIGRE Low Voltage distribution network

    DEFF Research Database (Denmark)

    Mustafa, Ghullam; Bak, Claus Leth; Buriro, Ehsan Ali

    2017-01-01

    Islanding is a condition where a portion of the power network comprising of the loads and Distributed Generation units is isolated from the rest of the power grid and forms a Micro Grid. In this condition, it becomes essential for the islanded MG to operate in a stable and controlled manner by pr...

  17. Multi-objective optimization of distributed generation with voltage ...

    African Journals Online (AJOL)

    DR OKE

    The limitation of traditional power generation, increasing power demand and benefits of distributed generation (DG) have been .... used in wind farms, mainly come under this category. ..... research interests are distributed generation planning, state estimation, short term forecasting, and AI application in power systems.

  18. Operational characteristics of a high voltage dense plasma focus

    Science.gov (United States)

    Woodall, D. M.

    1985-11-01

    A high voltage dense plasma focus powered by a single stage Marx bank was designed, built and operated. The maximum bank parameters are: voltage--120 kV, energy--20 kJ, short circuit current--600kA. The bank impedance is about 200 millohms. The plasma focus center electrode diameter is 1.27 cm. The outer electrode diameter is 10.16 cm. Rundown length is about 10 cm, corresponding to a bank quarter period of about 900 millohms ns. Rundown L is about 50 milliohms. The context of this work is established with a review of previous plasma focus theoretical, experimental and computational work and related topics. Theoretical motivation for high voltage operation is presented. The design, construction and operation of this device are discussed in detail. Results and analysis of measurements obtained are presented. Device operation was investigated primarily at 80 kV (9 kJ), with a gas fill of about 1 torr H2, plus 3-5 percent A. The following diagnostics were used: gun voltage and current measurements; filtered, time resolved x ray PIN measurements of the pinch region; time integrated x ray pinhole photographs of the pinch region; fast frame visible light photographs of the sheath during rundown; and B probe measurements of the current sheath shortly before collapse.

  19. Electronic Current Transducer (ECT) for high voltage dc lines

    Science.gov (United States)

    Houston, J. M.; Peters, P. H., Jr.; Summerayes, H. R., Jr.; Carlson, G. J.; Itani, A. M.

    1980-02-01

    The development of a bipolar electronic current transducer (ECT) for measuring the current in a high voltage dc (HVDC) power line at line potential is discussed. The design and construction of a free standing ECT for use on a 400 kV line having a nominal line current of 2000 A is described. Line current is measured by a 0.0001 ohm shunt whose voltage output is sampled by a 14 bit digital data link. The high voltage interface between line and ground is traversed by optical fibers which carry digital light signals as far as 300 m to a control room where the digital signal is converted back to an analog representation of the shunt voltage. Two redundant electronic and optical data links are used in the prototype. Power to operate digital and optical electronics and temperature controlling heaters at the line is supplied by a resistively and capacitively graded 10 stage cascade of ferrite core transformers located inside the hollow, SF6 filled, porcelain support insulator. The cascade is driven by a silicon controlled rectifier inverter which supplies about 100 W of power at 30 kHz.

  20. High transmembrane voltage raised by close contact initiates fusion pore

    Directory of Open Access Journals (Sweden)

    Bing Bu

    2016-12-01

    Full Text Available Membrane fusion lies at the heart of neuronal communication but the detailed mechanism of a critical step, fusion pore initiation, remains poorly understood. Here, through atomistic molecular dynamics simulations, a transient pore formation induced by a close contact of two apposed bilayers is firstly reported. Such a close contact gives rise to a high local transmembrane voltage that induces the transient pore formation. Through simulations on two apposed bilayers fixed at a series of given distances, the process in which two bilayers approaching to each other under the pulling force from fusion proteins for membrane fusion was mimicked. Of note, this close contact induced fusion pore formation is contrasted with previous reported electroporation under ad hoc applied external electric field or ionic charge in-balance. We show that the transmembrane voltage increases with the decrease of the distance between the bilayers. Below a critical distance, depending on the lipid composition, the local transmembrane voltage can be sufficiently high to induce the transient pores. The size of these pores is approximately 1~2 nm in diameter, which is large enough to allow passing of neurotransmitters. A resealing of the membrane pores resulting from the neutralization of the transmembrane voltage by ions through the pores was then observed. We also found that the membrane tension can either prolong the lifetime of transient pores or cause them to dilate for full collapse. This result provides a possible mechanism for fusion pore formation and regulation of pathway of fusion process.

  1. 30 CFR 18.54 - High-voltage continuous mining machines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage continuous mining machines. 18.54... and Design Requirements § 18.54 High-voltage continuous mining machines. (a) Separation of high-voltage components from lower voltage components. In each motor-starter enclosure, barriers, partitions...

  2. 30 CFR 75.705-2 - Repairs to energized surface high-voltage lines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Repairs to energized surface high-voltage lines... Repairs to energized surface high-voltage lines. An energized high-voltage surface line may be repaired... on power circuits with a phase-to-phase nominal voltage no greater than 15,000 volts; (3) Such...

  3. Square-Wave Voltage Injection Algorithm for PMSM Position Sensorless Control With High Robustness to Voltage Errors

    DEFF Research Database (Denmark)

    Ni, Ronggang; Xu, Dianguo; Blaabjerg, Frede

    2017-01-01

    relationship with the magnetic field distortion. Position estimation errors caused by higher order harmonic inductances and voltage harmonics generated by the SVPWM are also discussed. Both simulations and experiments are carried out based on a commercial PMSM to verify the superiority of the proposed method......Rotor position estimated with high-frequency (HF) voltage injection methods can be distorted by voltage errors due to inverter nonlinearities, motor resistance, and rotational voltage drops, etc. This paper proposes an improved HF square-wave voltage injection algorithm, which is robust to voltage...... errors without any compensations meanwhile has less fluctuation in the position estimation error. The average position estimation error is investigated based on the analysis of phase harmonic inductances, and deduced in the form of the phase shift of the second-order harmonic inductances to derive its...

  4. High-voltage plasma interactions calculations using NASCAP/LEO

    Science.gov (United States)

    Mandell, M. J.; Katz, I.

    1990-01-01

    This paper reviews four previous simulations (two laboratory and two space-flight) of interactions of a high-voltage spacecraft with a plasma under low-earth orbit conditions, performed using a three-dimensional computer code NASCAP/LEO. Results show that NASCAP/LEO can perform meaningful simulations of high-voltage plasma interactions taking into account three-dimensional effects of geometry, spacecraft motion, and magnetic field. Two new calculations are presented: (1) for current collection by 1-mm pinholes in wires (showing that a pinhole in a wire can collect far more current than a similar pinhole in a flat plate); and (2) current collection by Charge-2 mother vehicle launched in December 1985. It is shown that the Charge-2 calculations predicted successfully ion collection at negative bias, the floating potential of a probe outside or inside the sheath under negative bias conditions, and magnetically limited electron collection under electron beam operation at high altitude.

  5. Highly Reliable NPP Instrumentation Using Constant Voltage Feedback Circuits

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Seung J.; Choi, Bo H.; Kim, Ji H.; Rim, Chun T. [KAIST, Daejeon (Korea, Republic of)

    2014-08-15

    A highly reliable nuclear power plant (NPP) instrumentation using constant voltage feedback circuits is proposed. Contrary to conventional NPP instrumentation, two operational amplifiers are used at auxiliary building to supply constant DC voltage across the potentiometer or wheatstone bridge type sensors, such as resistance temperature detectors (RTD) and strain gauges. The proposed constant voltage feedback circuits maintain its output voltage as constant regardless of the length of lead wire from the auxiliary building to the sensors. A detail analysis of the proposed feedback circuits and design procedures including the internal resistance and parasitic LC components of lead wire are presented. A prototype with lumped RLC values for modeling lead wires is fabricated and experimentally verified to supply constant 10V up to 200m distance under 0.8% error. Due to its versatile characteristics with cost effective structure, the proposed scheme can be generally extended to pressure meters and water-level recorders to guarantee robust measurements without conventional current transducers under severe accidents.

  6. Locational Pricing to Mitigate Voltage Problems Caused by High PV Penetration

    Directory of Open Access Journals (Sweden)

    Sam Weckx

    2015-05-01

    Full Text Available In this paper, a locational marginal pricing algorithm is proposed to control the voltage in unbalanced distribution grids. The increasing amount of photovoltaic (PV generation installed in the grid may cause the voltage to rise to unacceptable levels during periods of low consumption. With locational prices, the distribution system operator can steer the reactive power consumption and active power curtailment of PV panels to guarantee a safe network operation. Flexible loads also respond to these prices. A distributed gradient algorithm automatically defines the locational prices that avoid voltage problems. Using these locational prices results in a minimum cost for the distribution operator to control the voltage. Locational prices can differ between the three phases in unbalanced grids. This is caused by a higher consumption or production in one of the phases compared to the other phases and provides the opportunity for arbitrage, where power is transferred from a phase with a low price to a phase with a high price. The effect of arbitrage is analyzed. The proposed algorithm is applied to an existing three-phase four-wire radial grid. Several simulations with realistic data are performed.

  7. High Voltage Power Converter for Large Wind Turbine

    DEFF Research Database (Denmark)

    Sztykiel, Michal

    system operates at 20 kV level - identical as for the collector distribution network. Medium voltage operation allows the converter unit along with the filter to be installed on the base platform inside the tower. In this manner, more space in the nacelle can be flexibly accommodated by the mechanical...... application. System B consists of the generator-side 2-level converter, DC/DC boost unit and a grid-side NPC-3L converter. System C is made of a seriesconnected full-bridge cells on the generator-side, and a grid-side NPC-5L converter. The performance of the proposed topologies is analyzed both under...

  8. Guidelines for Distribution System Operators on Reactive Power Provision by Electric Vehicles in Low Voltage Grids

    DEFF Research Database (Denmark)

    Zecchino, Antonio; Marinelli, Mattia; Træholt, Chresten

    2017-01-01

    The increasing success of electric vehicles is bringing new technical challenges to power system operators. This work intends to provide guidelines for distribution system operators in terms of reactive power requirements when evaluating and authorizing electric vehicles supply equipment with fast...... the amount of reactive power that an individual electric vehicle is expected to provide when connected to a low voltage feeder, in order to benefit of the desired voltage rise effect in comparison to the case of unitary power factor....

  9. A high voltage method for measuring low capacitance for tomography.

    Science.gov (United States)

    Lu, Decai; Shao, Fuqun; Guo, Zhiheng

    2009-05-01

    Low capacitance measurement is involved in many industrial applications, especially in the applications of electrical capacitance tomography (ECT). Most of the low capacitance measurement circuits employ an ac-based method or a charge/discharge method because of high sensitivity, high resolution, and immunity to stray capacitance; and its excitation or charge voltage are not more than 20 V. When ECT techniques for large industrial equipment such as blast furnaces or grain barns are explored, the existing methods for measuring low capacitance have some limitations. This paper proposes a high excitation voltage ac-based method for measuring low capacitance to improve the resolution of measurement. The method uses a high excitation voltage of several hundred volts and a transformer ratio arms as the C/V transducer. Experimental results indicate that the new method has a resolution of 0.005 fF, a good stability (about 0.003 fF over 4 h) and linearity (0.9992).

  10. Bottlenecks reduction using superconductors in high voltage transmission lines

    Directory of Open Access Journals (Sweden)

    Daloub Labib

    2016-01-01

    Full Text Available Energy flow bottlenecks in high voltage transmission lines known as congestions are one of the challenges facing power utilities in fast developing countries. Bottlenecks occur in selected power lines when transmission systems are operated at or beyond their transfer limits. In these cases, congestions result in preventing new power supply contracts, infeasibility in existing contracts, price spike and market power abuse. The “Superconductor Technology” in electric power transmission cables has been used as a solution to solve the problem of bottlenecks in energy transmission at high voltage underground cables and overhead lines. The increase in demand on power generation and transmission happening due to fast development and linked to the intensive usage of transmission network in certain points, which in turn, lead to often frequent congestion in getting the required power across to where it is needed. In this paper, a bottleneck in high voltage double overhead transmission line with Aluminum Conductor Steel Reinforced was modeled using conductor parameters and replaced by Gap-Type Superconductor to assess the benefit of upgrading to higher temperature superconductor and obtain higher current carrying capacity. This proved to reduce the high loading of traditional aluminum conductors and allow more power transfer over the line using superconductor within the same existing right-of-way, steel towers, insulators and fittings, thus reducing the upgrade cost of building new lines.

  11. Voltage-Level Selection of Future Two-Level LVdc Distribution Grids

    DEFF Research Database (Denmark)

    Diaz, Enrique Rodriguez; Chen, Fang; Quintero, Juan Carlos Vasquez

    2016-01-01

    significantly. Microgrids (MGs) come as a suitable solution for the installation of distributed sources in the low voltage grid, where most of the consumers are sparsely located. Microgrids ease the integration of distributed generators (DGs), especially renewable energy sources like solar panels and small wind...

  12. Rad-Hard, Miniaturized, Scalable, High-Voltage Switching Module for Power Applications Rad-Hard, Miniaturized

    Science.gov (United States)

    Adell, Philippe C.; Mojarradi, Mohammad; DelCastillo, Linda Y.; Vo, Tuan A.

    2011-01-01

    A paper discusses the successful development of a miniaturized radiation hardened high-voltage switching module operating at 2.5 kV suitable for space application. The high-voltage architecture was designed, fabricated, and tested using a commercial process that uses a unique combination of 0.25 micrometer CMOS (complementary metal oxide semiconductor) transistors and high-voltage lateral DMOS (diffusion metal oxide semiconductor) device with high breakdown voltage (greater than 650 V). The high-voltage requirements are achieved by stacking a number of DMOS devices within one module, while two modules can be placed in series to achieve higher voltages. Besides the high-voltage requirements, a second generation prototype is currently being developed to provide improved switching capabilities (rise time and fall time for full range of target voltages and currents), the ability to scale the output voltage to a desired value with good accuracy (few percent) up to 10 kV, to cover a wide range of high-voltage applications. In addition, to ensure miniaturization, long life, and high reliability, the assemblies will require intensive high-voltage electrostatic modeling (optimized E-field distribution throughout the module) to complete the proposed packaging approach and test the applicability of using advanced materials in a space-like environment (temperature and pressure) to help prevent potential arcing and corona due to high field regions. Finally, a single-event effect evaluation would have to be performed and single-event mitigation methods implemented at the design and system level or developed to ensure complete radiation hardness of the module.

  13. Pollution Maintenance Techniques in Coastal High Voltage Installations

    OpenAIRE

    Pyrgioti, E.; I. Vitellas; Thalassinakis, E.; D. Pylarinos; K. Siderakis

    2011-01-01

    Pollution of outdoor high voltage insulators is a common problem for utilities, with a considerable impact to power system reliability. In an effort to prevent possible flashovers due to pollution, many methods have been applied, aiming to improve the insulation performance, either by suppressing the formation of surface conductivity or by increasing the possible insulation level. In the case of substations, the selection of the appropriate technique is complex due to certain issues correlate...

  14. Prototype high voltage bushing: Configuration to its operational demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Sejal, E-mail: sshah@iter-india.org [ITER-India, Institute for Plasma Research, Bhat, Gandhinagar 382428 (India); Sharma, D. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India); Parmar, D.; Tyagi, H.; Joshi, K.; Shishangiya, H.; Bandyopadhyay, M.; Rotti, C.; Chakraborty, A. [ITER-India, Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)

    2016-12-15

    High Voltage Bushing (HVB) is the key component of Diagnostic Neutral Beam (DNB) system of ITER as it provides access to high voltage electrical, hydraulic, gas and diagnostic feedlines to the beam source with isolation from grounded vessel. HVB also provides primary vacuum confinement for the DNB system. Being Safety Important Class (SIC) component of ITER, it involves several configurational, technological and operational challenges. To ensure its operational performance & reliability, particularly electrostatic behavior, half scale down Prototype High Voltage Bushing (PHVB) is designed considering same design criteria of DNB HVB. Design optimization has been carried out followed by finite element (FE) analysis to obtain DNB HVB equivalent electric stress on different parts of PHVB, taking into account all design, manufacturing & space constraints. PHVB was tested up to 60 kV without breakdown, which validates its design for the envisaged operation of 50 kV DC. This paper presents the design of PHVB, FEA validation, manufacturing constraints, experimental layout with interfacing auxiliary systems and operational results related to functional performance.

  15. Health problems from radiation of high-voltage facilities

    Directory of Open Access Journals (Sweden)

    Hossein Ali Yousefi Rizi

    2013-01-01

    Full Text Available Aims: The aim of this study was to survey the health problems caused by exposure to high-voltage facility radiation. Materials and Methods: Sampling included workers exposed to electromagnetic fields at high-voltage facilities. The strength of the electric and magnetic fields was determined by a field meter. A questionnaire was used to evaluate the prevalence of subjective and psychological symptoms. Statistical descriptive used and data analyzed by a Student′s t-tests. Results: This study indicates that increased symptoms among the exposed workers including depression, anxiety, hostility, paranoia, inter-sensitivity, and obsession-compulsion. Some of the self-reported symptoms were, headache (53.5%, fatigue (35.6%, difficulties in concentration (32.5%, vertigo/dizziness (30.4%, attention disorders (28.8%, nervousness (28.1%, and palpitations (14.7%. A significant relationship was observed between the exposure to the electromagnetic field and psychological symptoms (P < 0.05. Conclusion: Radiation of high-voltage facilities probably increased the risk of mental disorders and intensified them in susceptible workers, especially depression. This finding confirmed the results obtained in provocative studies that indicated an increase in the risk of psychological symptoms, which was put forth by several investigators Observation of occupational health and other control measures play an important role in decreasing the symptoms.

  16. Design and Implementation of a High-Voltage Generator with Output Voltage Control for Vehicle ER Shock-Absorber Applications

    Directory of Open Access Journals (Sweden)

    Chih-Lung Shen

    2013-01-01

    Full Text Available A self-oscillating high-voltage generator is proposed to supply voltage for a suspension system in order to control the damping force of an electrorheological (ER fluid shock absorber. By controlling the output voltage level of the generator, the damping force in the ER fluid shock absorber can be adjusted immediately. The shock absorber is part of the suspension system. The high-voltage generator drives a power transistor based on self-excited oscillation, which converts dc to ac. A high-frequency transformer with high turns ratio is used to increase the voltage. In addition, the system uses the car battery as dc power supply. By regulating the duty cycle of the main switch in the buck converter, the output voltage of the buck converter can be linearly adjusted so as to obtain a specific high voltage for ER. The driving system is self-excited; that is, no additional external driving circuit is required. Thus, it reduces cost and simplifies system structure. A prototype version of the actual product is studied to measure and evaluate the key waveforms. The feasibility of the proposed system is verified based on experimental results.

  17. High Voltage Power Supply With High Output Current and Low Power Consumption for Photomultiplier Tubes

    Science.gov (United States)

    Cunha, José Paulo V. S.; Begalli, Marcia; Bellar, Maria Dias

    2012-04-01

    In some applications, photomultiplier tubes (PMTs) are powered by battery based circuits, where the available energy is severely limited. The most simple approach to design high voltage power supplies (HVPS) for PMTs has considered resistive voltage dividers in order to bias the dynodes. However, this approach usually results in high power losses and, consequently, this undermines the PMT performance. In this work, the proposed solution is the use of a power circuit based on the forward converter connected to a transformer built with several secondary windings. Each secondary voltage is rectified and filtered to eliminate voltage ripple. Each dynode voltage is supplied by a rectified secondary voltage. The proposed topology provides low power consumption as well as low sensitivity of the PMT gain with respect to the dynode currents. Taking into account the Waste Electrical and Electronic Equipment Directive (WEEE), this HVPS has been designed to allow the recycling of old PMTs.

  18. PHENIX Resistive Plate Chambers High Voltage Performance Analysis

    Science.gov (United States)

    Towell, Marshall; Phenix Collaboration

    2013-10-01

    The PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory studies polarized proton-proton collisions to better understand the spin structure of the proton. While RHIC is operating there are millions of collisions each second, but the PHENIX data acquisition system can only record a few thousand each second. To help select the rare events of interest, a new forward trigger has been commissioned that includes four stations of Resistive Plate Chambers (RPCs). During the most recent RHIC run, significant polarized proton-proton data were recorded with the new trigger for the first time. The RPC high voltage was recorded and studied for each module and each run. Every physics run was classified into one of four categories depending on its high voltage conditions, including the number of trips and the number and magnitude of mismatches between the HV set point and readback voltage. Each condition that was required to consider a run to have good HV was investigated systematically to determine the appropriate set points. The methods and results of this systematic study will be presented. This research was supported in part by the DOE under grant number DE-FG03-94ER40860.

  19. Process engineering of high voltage alginate encapsulation of mesenchymal stem cells.

    Science.gov (United States)

    Gryshkov, Oleksandr; Pogozhykh, Denys; Zernetsch, Holger; Hofmann, Nicola; Mueller, Thomas; Glasmacher, Birgit

    2014-03-01

    Encapsulation of stem cells in alginate beads is promising as a sophisticated drug delivery system in treatment of a wide range of acute and chronic diseases. However, common use of air flow encapsulation of cells in alginate beads fails to produce beads with narrow size distribution, intact spherical structure and controllable sizes that can be scaled up. Here we show that high voltage encapsulation (≥ 15 kV) can be used to reproducibly generate spherical alginate beads (200-400 μm) with narrow size distribution (± 5-7%) in a controlled manner under optimized process parameters. Flow rate of alginate solution ranged from 0.5 to 10 ml/h allowed producing alginate beads with a size of 320 and 350 μm respectively, suggesting that this approach can be scaled up. Moreover, we found that applied voltages (15-25 kV) did not alter the viability and proliferation of encapsulated mesenchymal stem cells post-encapsulation and cryopreservation as compared to air flow. We are the first who employed a comparative analysis of electro-spraying and air flow encapsulation to study the effect of high voltage on alginate encapsulated cells. This report provides background in application of high voltage to encapsulate living cells for further medical purposes. Long-term comparison and work on alginate-cell interaction within these structures will be forthcoming. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. New Requirements of the Voltage/VAR Function for Smart Inverter in Distributed Generation Control

    Directory of Open Access Journals (Sweden)

    Yun-Su Kim

    2016-11-01

    Full Text Available International Electronical Committee (IEC 61850-90-7 is a part of the IEC 61850 series which specifies the advanced functions and object models for power converter based Distributed Energy Resources (DERs. One of its functions, the Voltage/VAR (V/V control function, is used to enhance the stability and the reliability of the voltage in the distribution system. The conventional V/V function acts mainly for flattening the voltage profile as for a basic grid support function. Currently, other objectives such as the minimization of line loss and the operational costs reduction are coming into the spotlight. In order to attain these objectives, the V/V function and hence the DER units shall actively respond to the change of distribution system conditions. In this paper, the modification of V/V function and new requirements are proposed. To derive new requirements of V/V function, loss minimization is applied to a particle swarm optimization (PSO algorithm where the condition of voltage constraint is considered not to deteriorate the voltage stability of the distribution system.

  1. Optimal reactive power and voltage control in distribution networks with distributed generators by fuzzy adaptive hybrid particle swarm optimisation method

    DEFF Research Database (Denmark)

    Chen, Shuheng; Hu, Weihao; Su, Chi

    2015-01-01

    A new and efficient methodology for optimal reactive power and voltage control of distribution networks with distributed generators based on fuzzy adaptive hybrid PSO (FAHPSO) is proposed. The objective is to minimize comprehensive cost, consisting of power loss and operation cost of transformers...... that the proposed method can search a more promising control schedule of all transformers, all capacitors and all distributed generators with less time consumption, compared with other listed artificial intelligent methods....

  2. High voltage characteristics of junctionless poly-silicon thin film transistors

    Science.gov (United States)

    Cheng, Ya-Chi; Wu, Yung-Chun; Chen, Hung-Bin; Han, Ming-Hung; Lu, Nan-Heng; Su, Jun-Ji; Chang, Chun-Yen

    2013-09-01

    The breakdown voltage (VBD) and breakdown mechanism of junctionless (JL) poly-Si thin film transistor (TFT) were compared to the conventional inversion-mode (IM) TFT using fabricated devices and 3D quantum-corrected hydrodynamic transport device simulation. The simulated results are correspondent with experimental ones. The analyses of electric field distributions in on-state show that the channel of JL devices can equally share the voltage like a resistor, because there are no junctions formed between channel and source/drain. The JL TFT shows excellent breakdown characteristics; the off-state VBD of 53.4 V is several times larger than VBD of 9.5 V in IM TFT with same device size. JL devices have large potential for high voltage power metal-oxide-semiconductor devices and circuit applications.

  3. Measurements and interpretations concerning leakage currents on polluted high voltage insulators

    Science.gov (United States)

    Thalassinakis, E.; Karagiannopoulos, C. G.

    2003-04-01

    This paper presents data that may aid physical interpretation of leakage currents on insulators suffering pollution under real physical conditions. The measurements were performed on the power distribution system on the island of Crete. An on-line recording system has been installed on the insulators of the 150 kV network, in order to monitor the leakage currents on the polluted insulators and investigate the various parameters of the phenomena. It is convincingly shown that in the timeframe of one period of 50 Hz, above a threshold voltage value (smaller than the peak voltage) a non-linear i-v relationship may develop, leading to bistability and non-linear conductance phenomena. The well-established theory regarding leakage currents on high voltage insulators, as well as that concerning dielectrics in strong electric fields, provide the required theoretical basis for the interpretation of the experimental results obtained.

  4. Local Voltage Control in Distribution Networks: A Game-Theoretic Perspective: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xinyang; Tian, Jie; Chen, Lijun; Dall' Anese, Emiliano

    2016-09-01

    Inverter-based voltage regulation is gaining importance to alleviate emerging reliability and power-quality concerns related to distribution systems with high penetration of photovoltaic (PV) systems. This paper seeks contribution in the domain of reactive power compensation by establishing stability of local Volt/VAr controllers. In lieu of the approximate linear surrogate used in the existing work, the paper establishes existence and uniqueness of an equilibrium point using nonlinear AC power flow model. Key to this end is to consider a nonlinear dynamical system with non-incremental local Volt/VAr control, cast the Volt/VAr dynamics as a game, and leverage the fixed-point theorem as well as pertinent contraction mapping argument. Numerical examples are provided to complement the analytical results.

  5. Dynamic Consensus Algorithm based Distributed Voltage Harmonic Compensation in Islanded Microgrids

    DEFF Research Database (Denmark)

    Meng, Lexuan; Tang, Fen; Firoozabadi, Mehdi Savaghebi

    2015-01-01

    In islanded microgrids, the existence of nonlinear electric loads may cause voltage distortion and affect the performance of power quality sensitive equipment. Thanks to the prevalent utilization of interfacing power electronic devices and information/communication technologies, distributed...... generators can be employed as compensators to enhance the power quality on consumer side. However, conventional centralized control is facing obstacles because of the distributed fashion of generation and consumption. Accordingly, this paper proposes a consensus algorithm based distributed hierarchical...

  6. Experimental validation of a high voltage pulse measurement method.

    Energy Technology Data Exchange (ETDEWEB)

    Cular, Stefan; Patel, Nishant Bhupendra; Branch, Darren W.

    2013-09-01

    This report describes X-cut lithium niobates (LiNbO3) utilization for voltage sensing by monitoring the acoustic wave propagation changes through LiNbO3 resulting from applied voltage. Direct current (DC), alternating current (AC) and pulsed voltage signals were applied to the crystal. Voltage induced shift in acoustic wave propagation time scaled quadratically for DC and AC voltages and linearly for pulsed voltages. The measured values ranged from 10 - 273 ps and 189 ps 2 ns for DC and non-DC voltages, respectively. Data suggests LiNbO3 has a frequency sensitive response to voltage. If voltage source error is eliminated through physical modeling from the uncertainty budget, the sensors U95 estimated combined uncertainty could decrease to ~0.025% for DC, AC, and pulsed voltage measurements.

  7. A High Voltage Swing 1.9 GHz PA in Standard CMOS

    NARCIS (Netherlands)

    Aartsen, W.A.J.; Annema, Anne J.; Nauta, Bram

    A circuit technique for RF power amplifiers that reliably handle voltage peaks well above the nominal supply voltage is presented. To achieve this high-voltage tolerance the circuit implements switched-cascode transistors that yield reliable operation for voltages up to 7V at RF frequencies in a

  8. Smart Demand for Improving Short-term Voltage Control on Distribution Networks

    DEFF Research Database (Denmark)

    Garcia-Valle, Rodrigo; P. Da Silva, Luiz C.; Xu, Zhao

    2009-01-01

    Smart grids must involve active roles from end users in order to be truly smart. The energy consumption has to be done in a flexible and intelligent manner, in accordance with the current conditions of the power system. Moreover, with the advent of dispersed and renewable generation, increasing...... customer integration to aid power system performance is almost inevitable. This study introduces a new type of smart demand side technology, denoted demand as voltage controlled reserve (DVR), to improve short-term voltage control, where customers are expected to play a more dynamic role to improve voltage...... control. The technology can be provided by thermostatically controlled loads as well as other types of load. This technology is proven to be effective in case of distribution systems with a large composition of induction motors, where the voltage presents a slow recovery characteristic due to deceleration...

  9. Impact of Solar Array Designs on High Voltage Operations

    Science.gov (United States)

    Brandhorst, Henry W., Jr.; Ferguson, Dale; Piszczor, Mike; ONeill, Mark

    2006-01-01

    As power levels of advanced spacecraft climb above 25 kW, higher solar array operating voltages become attractive. Even in today s satellites, operating spacecraft buses at 100 V and above has led to arcing in GEO communications satellites, so the issue of spacecraft charging and solar array arcing remains a design problem. In addition, micrometeoroid impacts on all of these arrays can also lead to arcing if the spacecraft is at an elevated potential. For example, tests on space station hardware disclosed arcing at 75V on anodized A1 structures that were struck with hypervelocity particles in Low Earth Orbit (LEO) plasmas. Thus an understanding of these effects is necessary to design reliable high voltage solar arrays of the future, especially in light of the Vision for Space Exploration of NASA. In the future, large GEO communication satellites, lunar bases, solar electric propulsion missions, high power communication systems around Mars can lead to power levels well above 100 kW. As noted above, it will be essential to increase operating voltages of the solar arrays well above 80 V to keep the mass of cabling needed to carry the high currents to an acceptable level. Thus, the purpose of this paper is to discuss various solar array approaches, to discuss the results of testing them at high voltages, in the presence of simulated space plasma and under hypervelocity impact. Three different types of arrays will be considered. One will be a planar array using thin film cells, the second will use planar single or multijunction cells and the last will use the Stretched Lens Array (SLA - 8-fold concentration). Each of these has different approaches for protection from the space environment. The thin film cell based arrays have minimal covering due to their inherent radiation tolerance, conventional GaAs and multijunction cells have the traditional cerium-doped microsheet glasses (of appropriate thickness) that are usually attached with Dow Corning DC 93-500 silicone

  10. Study on cathode high voltage pulse control in image intensifier

    Science.gov (United States)

    Yang, Ye; Yan, Bo; Ni, Xiao-bing; Zhi, Qiang; Li, Jun-guo; Yao, Ze; Deng, Guang-xu

    2016-03-01

    This paper briefly introduces the basic working principle of auto-gating power source. Due to the presence of noise in the circuit, the cathode pulse signal generated by the AD converter is unstable. In this paper, the circuit of the AD converter is adjusted to improve the instability of the cathode high voltage pulse signal, especially in the case of low light and high illumination to avoid the jitter of the pulse. The experiment was carried out. And it could guide the implementation of this part of the circuit.

  11. Spacecraft-generated plasma interaction with high voltage solar array

    Science.gov (United States)

    Parks, D. E.; Katz, I.

    1978-01-01

    Calculations are made of the effect of interactions of spacecraft-generated plasmas and high voltage solar array components on an advanced Solar Electric Propulsion system. The plasma consists of mercury ions and electrons resulting from the operation of ion thrusters and associated hollow cathode neutralizers. Because large areas of the solar array are at high potential and not completely insulated from the surrounding plasma, the array can, under some conditions, collect excessive electron currents. Results are given for the parasitic currents collected by the solar arrays and means for reducing these currents are considered.

  12. New perspectives in vacuum high voltage insulation. II. Gas desorption

    CERN Document Server

    Diamond, W T

    1998-01-01

    An examination has been made of gas desorption from unbaked electrodes of copper, niobium, aluminum, and titanium subjected to high voltage in vacuum. It has been shown that the gas is composed of water vapor, carbon monoxide, and carbon dioxide, the usual components of vacuum outgassing, plus an increased yield of hydrogen and light hydrocarbons. The gas desorption was driven by anode conditioning as the voltage was increased between the electrodes. The gas is often desorbed as microdischarges-pulses of a few to hundreds of microseconds-and less frequently in a more continuous manner without the obvious pulsed structure characteristic of microdischarge activity. The quantity of gas released was equivalent to many monolayers and consisted mostly of neutral molecules with an ionic component of a few percent. A very significant observation was that the gas desorption was more dependent on the total voltage between the electrodes than on the electric field. It was not triggered by field-emitted electrons but oft...

  13. Design of Plasma Generator Driven by High-frequency High-voltage Power Supply

    Directory of Open Access Journals (Sweden)

    C. Yong-Nong

    2013-04-01

    Full Text Available In this research, a high-frequency high-voltage power supply designed for plasma generator is presented. The power supply mainly consists of a series resonant converter with a high-frequency high-voltage boost transformer. Due to the indispensable high-voltage inheritance in the operation of plasma generator, the analysis of transformer need considering not only winding resistance, leakage inductance, magnetizing inductance, and core-loss resistance, but also parasitic capacitance resulted from the insulation wrappings on the high-voltage side. This research exhibits a simple approach to measuring equivalent circuit parameters of the high-frequency, high-voltage transformer with stray capacitance being introduced into the conventional modeling. The proposed modeling scheme provides not only a precise measurement procedure but also effective design information for series-load resonant converter. The plasma discharging plate is designed as part of the electric circuit in the series load-resonant converter and the circuit model of the plasma discharging plate is also conducted as well. Thus, the overall model of the high-voltage plasma generator is built and the designing procedures for appropriate selections of the corresponding resonant-circuit parameters can be established. Finally, a high-voltage plasma generator with 220V, 60Hz, and 1kW input, along with a 22 kHz and over 8kV output, is realized and implemented.

  14. Design of Plasma Generator Driven by High-frequency High-voltage Power Supply

    Directory of Open Access Journals (Sweden)

    C. Yong-Nong

    2013-03-01

    Full Text Available In this research, a high-frequency high-voltage power supply designed for plasma generator is presented. The powersupply mainly consists of a series resonant converter with a high-frequency high-voltage boost transformer. Due to theindispensable high-voltage inheritance in the operation of plasma generator, the analysis of transformer needconsidering not only winding resistance, leakage inductance, magnetizing inductance, and core-loss resistance, butalso parasitic capacitance resulted from the insulation wrappings on the high-voltage side. This research exhibits asimple approach to measuring equivalent circuit parameters of the high-frequency, high-voltage transformer with straycapacitance being introduced into the conventional modeling. The proposed modeling scheme provides not only aprecise measurement procedure but also effective design information for series-load resonant converter. The plasmadischarging plate is designed as part of the electric circuit in the series load-resonant converter and the circuit modelof the plasma discharging plate is also conducted as well. Thus, the overall model of the high-voltage plasmagenerator is built and the designing procedures for appropriate selections of the corresponding resonant-circuitparameters can be established. Finally, a high-voltage plasma generator with 220V, 60Hz, and 1kW input, along witha 22 kHz and over 8kV output, is realized and implemented.

  15. Distributed voltage control and load sharing for inverter-interfaced microdrid with resistive lines

    DEFF Research Database (Denmark)

    Golsorkhi, Mohammad S.; Lu, D. D C; Shafiee, Q.

    2016-01-01

    method is based upon the practical assumption of resistive network impedance. In this context, a V-I droop mechanism is adopted in the primary control level, where GPS timing is used to synchronize the control agents. A new distributed secondary control method based on consensus protocol is introduced......This paper proposes a new distributed control method for coordination of distributed energy resources (DERs) in low-voltage resistive microgrids. The proposed framework consists of two level structure; primary and secondary control. Unlike the existing distributed control methods, the proposed......-axis component of voltage is adjusted to perform proper current and, accordingly reactive power sharing. The proposed control methodology accounts for the distribution line impedances. It features a plug-and-play environment; prior system knowledge is not required, and an arbitrary DER can enter the microgrid...

  16. Calculation of surface leakage currents on high voltage insulators by ant colony algorithm-supported FEM

    OpenAIRE

    ÖZTÜRK, DURSUN; CEBECİ, MEHMET

    2015-01-01

    The weakness of the outer insulation at high voltages is the reduction of the surface resistance as a result of the environmental pollution yielding formation of flashover due to the surface leakage currents. In this study, it was shown how to calculate the surface leakage currents resulting in flashover in polluted insulators and therefore power cuts by means of the ant colony algorithm (ACA). For this purpose, first, field distribution on the sample insulator surface in question was defined...

  17. SEMICONDUCTOR DEVICES: A novel high voltage start up circuit for an integrated switched mode power supply

    Science.gov (United States)

    Hao, Hu; Xingbi, Chen

    2010-09-01

    A novel high voltage start up circuit for providing an initial bias voltage to an integrated switched mode power supply (SMPS) is presented. An enhanced mode VDMOS transistor, the gate of which is biased by a floating p-island, is used to provide start up current and sustain high voltage. An NMOS transistor having a high source to ground breakdown voltage is included to extend the bias voltage range to the SMPS. Simulation results indicate that the high voltage start up circuit can start and restart as designed. The proposed structure is believed to be more energy saving and cost-effective compared with other solutions.

  18. Calibration of the ISOLDE acceleration voltage using a high-precision voltage divider and applying collinear fast beam laser spectroscopy

    CERN Document Server

    Krieger, A.; Catherall, R.; Hochschulz, F.; Kramer, J.; Neugart, R.; Rosendahl, S.; Schipper, J.; Siesling, E.; Weinheimer, Ch.; Yordanov, D.T.; Nortershauser, W.

    2011-01-01

    A high-voltage divider with accuracy at the ppm level and collinear laser spectroscopy were used to calibrate the highvoltage installation at the radioactive ion beam facility ISOLDE at CERN. The accurate knowledge of this voltage is particularly important for collinear laser spectroscopy measurements. Beam velocity measurements using frequencycomb based collinear laser spectroscopy agree with the new calibration. Applying this, one obtains consistent results for isotope shifts of stable magnesium isotopes measured using collinear spectroscopy and laser spectroscopy on laser-cooled ions in a trap. The long-term stability and the transient behavior during recovery from a voltage dropout were investigated for the different power supplies currently applied at ISOLDE.

  19. Test Results from a Simulated High Voltage Lunar Power Transmission Line

    Science.gov (United States)

    Birchenough, Arthur; Hervol, David

    2008-01-01

    The Alternator Test Unit (ATU) in the Lunar Power System Facility (LPSF) located at the NASA Glenn Research Center (GRC) in Cleveland, OH was modified to simulate high voltage transmission capability. The testbed simulated a 1 km transmission cable length from the ATU to the LPSF using resistors and inductors installed between the distribution transformers. Power factor correction circuitry was used to compensate for the reactance of the distribution system to improve the overall power factor. This test demonstrated that a permanent magnet alternator can successfully provide high frequency AC power to a lunar facility located at a distance.

  20. Test Results From a Simulated High-Voltage Lunar Power Transmission Line

    Science.gov (United States)

    Birchenough, Arthur; Hervol, David

    2008-01-01

    The Alternator Test Unit (ATU) in the Lunar Power System Facility (LPSF) located at the NASA Glenn Research Center (GRC) in Cleveland, Ohio was modified to simulate high-voltage transmission capability. The testbed simulated a 1 km transmission cable length from the ATU to the LPSF using resistors and inductors installed between the distribution transformers. Power factor correction circuitry was used to compensate for the reactance of the distribution system to improve the overall power factor. This test demonstrated that a permanent magnet alternator can successfully provide high-frequency ac power to a lunar facility located at a distance.

  1. Distributed Optimal Control of Reactive Power and Voltage in Islanded Microgrids

    DEFF Research Database (Denmark)

    Wang, Yanbo; Wang, Xiongfei; Chen, Zhe

    2017-01-01

    This paper presents a distributed optimal control strategy for islanded microgrids, which allows to perform reactive power sharing and voltage regulation without using communication system. To perform the twofold objectives, a small signal model is first developed to reconstruct the system input...... performance of the optimal controller is analyzed, from which the guideline for choosing controller parameters is formulated. The results obtained from sensitivity analysis, simulations and experiments show that the proposed approach provides the expected reliability and flexibility for optimizing......-output relationship, which is evaluated through sensitivity analysis. A state estimator is then constructed to observe reactive power distribution and system voltages by local measurement. An optimal regulator is developed to perform both reactive power sharing and system voltage restoration. And the dynamic...

  2. Distributed Optimal Control of Reactive Power and Voltage in Islanded Microgrids

    DEFF Research Database (Denmark)

    Wang, Yanbo; Wang, Xiongfei; Chen, Zhe

    2016-01-01

    The paper proposes a distributed optimal control strategy for islanded microgrids, which allows to perform reactive power sharing and voltage regulation without communication system. To realize the twofold objective, an improved small signal model is developed first to reconstruct the system input...... power sharing and system voltage restoration. And the dynamic performance of the optimal controller is analyzed, from which the guideline for choosing controller parameters is formulated. The results obtained from sensitivity analysis, simulations and experiments show that the proposed approach provides......-output relationship, where the relationship is evaluated with sensitivity analysis. A state estimator is then constructed based on the new input-output relationship in order to observe reactive power distribution and system voltages by local measurement. An optimal regulator is developed to perform both reactive...

  3. Self-monitoring high voltage transmission line suspension insulator

    Science.gov (United States)

    Stemler, Gary E.; Scott, Donald N.

    1981-01-01

    A high voltage transmission line suspension insulator (18 or 22) which monitors its own dielectric integrity. A dielectric rod (10) has one larger diameter end fitting attachable to a transmission line and another larger diameter end fitting attachable to a support tower. The rod is enclosed in a dielectric tube (14) which is hermetically sealed to the rod's end fittings such that a liquidtight space (20) is formed between the rod and the tube. A pressurized dielectric liquid is placed within that space. A discoloring dye placed within this space is used to detect the loss of the pressurized liquid.

  4. Distribution-Connected PV's Response to Voltage Sags at Transmission-Scale

    Energy Technology Data Exchange (ETDEWEB)

    Mather, Barry; Ding, Fei

    2016-11-21

    The ever increasing amount of residential- and commercial-scale distribution-connected PV generation being installed and operated on the U.S.'s electric power system necessitates the use of increased fidelity representative distribution system models for transmission stability studies in order to ensure the continued safe and reliable operation of the grid. This paper describes a distribution model-based analysis that determines the amount of distribution-connected PV that trips off-line for a given voltage sag seen at the distribution circuit's substation. Such sags are what could potentially be experienced over a wide area of an interconnection during a transmission-level line fault. The results of this analysis show that the voltage diversity of the distribution system does cause different amounts of PV generation to be lost for differing severity of voltage sags. The variation of the response is most directly a function of the loading of the distribution system. At low load levels the inversion of the circuit's voltage profile results in considerable differences in the aggregated response of distribution-connected PV Less variation is seen in the response to specific PV deployment scenarios, unless pushed to extremes, and in the total amount of PV penetration attained. A simplified version of the combined CMPLDW and PVD1 models is compared to the results from the model-based analysis. Furthermore, the parameters of the simplified model are tuned to better match the determined response. The resulting tuning parameters do not match the expected physical model of the distribution system and PV systems and thus may indicate that another modeling approach would be warranted.

  5. Voltage Control Scheme with Distributed Generation and Grid Connected Converter in a DC Microgrid

    Directory of Open Access Journals (Sweden)

    Jong-Chan Choi

    2014-10-01

    Full Text Available Direct Current (DC microgrids are expected to become larger due to the rapid growth of DC energy sources and power loads. As the scale of the system expends, the importance of voltage control will be increased to operate power systems stably. Many studies have been performed on voltage control methods in a DC microgrid, but most of them focused only on a small scale microgrid, such as a building microgrid. Therefore, a new control method is needed for a middle or large scale DC microgrid. This paper analyzes voltage drop problems in a large DC microgrid and proposes a cooperative voltage control scheme with a distributed generator (DG and a grid connected converter (GCC. For the voltage control with DGs, their location and capacity should be considered for economic operation in the systems. Accordingly, an optimal DG allocation algorithm is proposed to minimize the capacity of a DG for voltage control in DC microgrids. The proposed methods are verified with typical load types by a simulation using MATLAB and PSCAD/EMTDC.

  6. Spatial and temporal instabilities in high voltage power devices

    Energy Technology Data Exchange (ETDEWEB)

    Milady, Saeed

    2010-01-29

    Dynamic avalanche can occur during the turn-off process of high voltage bipolar devices, e.g. IGBTs and p{sup +}n{sup -}n{sup +} power diodes, that may result in spatial instabilities of the homogeneous current density distribution across the device and the formation of current filaments. Filaments may cause the destruction of the device, mainly because of the high local temperatures. The first part of this work is dedicated to the current filament behavior. The positive feedback mechanisms caused by the transient current flow through the gate capacitance of an IGBT operating under short circuit conditions may result in oscillations and temporal instabilities of the IGBT current. The oscillations may cause electromagnetic interference (EMI). Furthermore, the positive feedback mechanism may accelerate the over-heating of the device and result in a thermal run-away. This is the subject of the second part of this work. In the first part of this work using the device simulation results of power diodes the underlying physical mechanisms of the filament dynamic is investigated. Simulation results of diode structures with evenly distributed doping inhomogeneities show that, the filament motion gets smoother as the distance between the inhomogeneities decreases. Hopping to faraway inhomogeneities turns into the hopping to neighboring ones and finally a smooth motion. In homogeneous structures the slow inhibitory effect of the electron-hole plasma extraction and the fast activation, due to hole current flowing along the filament, result in a smooth filament motion. An analytical model for the filament velocity under isothermal conditions is presented that can reproduce the simulation data satisfactorily. The influence of the boundary conditions on the filament behavior is discussed. The positive beveled edge termination prohibits a long stay of the filament at the edge reducing the risk of filament pinning. Self-heating effects may turn the initially electrically triggered

  7. 30 CFR 77.704-1 - Work on high-voltage lines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Work on high-voltage lines. 77.704-1 Section 77... MINES Grounding § 77.704-1 Work on high-voltage lines. (a) No high-voltage line shall be regarded as... provided in § 77.103) that such high-voltage line has been deenergized and grounded. Such qualified person...

  8. Impact and Cost Evaluation of Electric Vehicle Integration on Medium Voltage Distribution Networks

    DEFF Research Database (Denmark)

    Wu, Qiuwei; Cheng, Lin; Pineau, Ulysse

    2013-01-01

    This paper presents the analysis of the impact of electric vehicle (EV) integration on medium voltage (MV) distribution networks and the cost evaluation of replacing the overloaded grid components. A number of EV charging scenarios have been studied. A 10 kV grid from the Bornholm Island...

  9. Grid Voltage Synchronization for Distributed Generation Systems under Grid Fault Conditions

    DEFF Research Database (Denmark)

    Luna, Alvaro; Rocabert, J.; Candela, I.

    2015-01-01

    The actual grid code requirements for the grid connection of distributed generation systems, mainly wind and PV systems, are becoming very demanding. The Transmission System Operators (TSOs) are especially concerned about the Low Voltage Ride Through requirements. Solutions based on the installat...

  10. A structured approach to increase situational awareness in low voltage distribution grids

    NARCIS (Netherlands)

    Helmholt, K.A.; Groote Schaarsberg, M.; Broersma, T.; Morren, J.; Kruizinga, B.; Wouters, P.A.A.F.; Steennis, E.F.; Baldinger, F.

    2015-01-01

    Wear and tear, electrification and aging of (low voltage) distribution grids require maintenance in order to assure continuous provision of electricity. Situational awareness is required to find out when parts of the grid need maintenance and which parts should be prioritized. The paper proposes a

  11. Grid modeling, analysis and simulation of different scenarios for a smart low-voltage distribution grid

    DEFF Research Database (Denmark)

    Mihet-Popa, Lucian; Han, Xue; Bindner, Henrik W.

    2013-01-01

    , the number of cabinets and customers and the load per customer. The aim of the model is to design, implement and test the proposed configuration and to investigate whether the low-voltage distribution grid is prepared for the expected future increase of PV penetration, heat pumps and electric cars. The model...

  12. Deployment strategy for battery energy storage system in distribution network based on voltage violation regulation

    Science.gov (United States)

    Wu, H.; Zhou, L.; Xu, T.; Fang, W. L.; He, W. G.; Liu, H. M.

    2017-11-01

    In order to improve the situation of voltage violation caused by the grid-connection of photovoltaic (PV) system in a distribution network, a bi-level programming model is proposed for battery energy storage system (BESS) deployment. The objective function of inner level programming is to minimize voltage violation, with the power of PV and BESS as the variables. The objective function of outer level programming is to minimize the comprehensive function originated from inner layer programming and all the BESS operating parameters, with the capacity and rated power of BESS as the variables. The differential evolution (DE) algorithm is applied to solve the model. Based on distribution network operation scenarios with photovoltaic generation under multiple alternative output modes, the simulation results of IEEE 33-bus system prove that the deployment strategy of BESS proposed in this paper is well adapted to voltage violation regulation invariable distribution network operation scenarios. It contributes to regulating voltage violation in distribution network, as well as to improve the utilization of PV systems.

  13. An accurate continuous calibration system for high voltage current transformer.

    Science.gov (United States)

    Tong, Yue; Li, Bin Hong

    2011-02-01

    A continuous calibration system for high voltage current transformers is presented in this paper. The sensor of this system is based on a kind of electronic instrument current transformer, which is a clamp-shape air core coil. This system uses an optical fiber transmission system for its signal transmission and power supply. Finally the digital integrator and fourth-order convolution window algorithm as error calculation methods are realized by the virtual instrument with a personal computer. It is found that this system can calibrate a high voltage current transformer while energized, which means avoiding a long calibrating period in the power system and the loss of power metering expense. At the same time, it has a wide dynamic range and frequency band, and it can achieve a high accuracy measurement in a complex electromagnetic field environment. The experimental results and the on-site operation results presented in the last part of the paper, prove that it can reach the 0.05 accuracy class and is easy to operate on site.

  14. Survey of high voltage electron microscopy worldwide in 1998.

    Energy Technology Data Exchange (ETDEWEB)

    Allen, C. W.

    1998-03-05

    High voltage TEMs were introduced commercially thirty years ago, with the installations of 500 kV Hitachi instruments at the Universities of Nagoya and Tokyo. Since that time 53 commercial instruments, having maximum accelerating potentials of 0.5-3.5 MV, will have been delivered by the end of 1998. Table 1 summarizes the sites and some information regarding those HVEMS which are available in 1998. This corrects, updates and expands an earlier report of this sort [2]. There have been three commercial HVEM manufacturers: AEI (UK), Hitachi and JEOL (Japan). The proportion of the total number of HVEMS produced by each manufacturer is similar to that reflected in Table 1: AEI and Kratos/AEI (12), Hitachi (20) and JEOL (21). The term Kratos/AEI refers to instruments delivered after the takeover of AEI by Grates in the late 1970's. In Table 1 only maximum accelerating potentials are listed, which is generally also the design value for which the resolution for imaging was optimized. It is important to realize that in many applications, especially those studying irradiation effects, much lower voltages may be employed somewhat routinely to minimize atom displacements by the incident electron beam during analysis. These minimum values range from 100 kV for the AEI and Kratos/AEI instruments to typically 400 kV for the current generation of atomic resolution instruments, the latter being well above the thresholds for displacement in light elements such as Al and Si and for displacement of anions in many ceramic materials such as the high Tc superconductors, for example. An additional potential problem is electron-induced sputtering and differential sputtering (unequal sputtering rates in multicomponent materials), especially when accurate elemental microanalysis is being attempted. These same issues may arise for intermediate voltage TEMs as well, of course.

  15. Distributed Voltage Unbalance Compensation in Islanded Microgrids by Using Dynamic-Consensus-Algorithm

    DEFF Research Database (Denmark)

    Meng, Lexuan; Zhao, Xin; Tang, Fen

    2016-01-01

    In islanded microgrids (MGs), distributed generators (DGs) can be employed as distributed compensators for improving the power quality in the consumer side. Two-level hierarchical control can be used for voltage unbalance compensation. Primary level, consisting of droop control and virtual...... impedance, can be applied to help the positive sequence active and reactive power sharing. Secondary level is used to assist voltage unbalance compensation. However, if distribution line differences are considered, the negative sequence current cannot be well shared among DGs. In order to overcome...... this problem, this paper proposes a distributed negative sequence current sharing method by using a dynamic consensus algorithm (DCA). In clear contrast with the previously proposed methods, this approach does not require a dedicated central controller and the communication links are only required between...

  16. An evaluation method of voltage sag using a risk assessment model in power distribution systems

    Energy Technology Data Exchange (ETDEWEB)

    Sang Yun Yun [LG Industrial Systems, Cheongju (Korea). Electrotechnology R and D Center; Jae Chul Kim [Soongsil Univ., Seoul (Korea). Dept. of Electrical Engineering

    2003-12-01

    In this paper we explore a new method for evaluating the impact of voltage sags in the power distribution systems. The proposed method incorporates the generalization of the evaluation method as well as the effects of voltage sags on customers. To generalize the evaluation method, historical reliability data will be used. We take into account the impact of voltage sags on customers using a representative power acceptability curve and a fuzzy model. The final result of the evaluation model yields on a yearly basis the magnitude of customers' risk caused by voltage sags. The evaluation methodology is divided into the analytic and probabilistic method. The time sequential Monte Carlo simulation is used as probabilistic method. The proposed method is tested using the modified Roy Billinton Test System (RBTS) form and the reliability data of Korea Electric Power Corporation (KEPCO) system. Through the case study, we verify that the proposed method evaluate the actual impact of voltage sags and can be effectively applied to the real system using the historical reliability data as the conventional reliability indices in power distribution systems. (author)

  17. Low power, high voltage power supply with fast rise/fall time

    Science.gov (United States)

    Bearden, Douglas B. (Inventor)

    2007-01-01

    A low power, high voltage power supply system includes a high voltage power supply stage and a preregulator for programming the power supply stage so as to produce an output voltage which is a predetermined fraction of a desired voltage level. The power supply stage includes a high voltage, voltage doubler stage connected to receive the output voltage from the preregulator and for, when activated, providing amplification of the output voltage to the desired voltage level. A first feedback loop is connected between the output of the preregulator and an input of the preregulator while a second feedback loop is connected between the output of the power supply stage and the input of the preregulator.

  18. Novel Interleaved Converter with Extra-High Voltage Gain to Process Low-Voltage Renewable-Energy Generation

    Directory of Open Access Journals (Sweden)

    Chih-Lung Shen

    2016-10-01

    Full Text Available This paper presents a novel interleaved converter (NIC with extra-high voltage gain to process the power of low-voltage renewable-energy generators such as photovoltaic (PV panel, wind turbine, and fuel cells. The NIC can boost a low input voltage to a much higher voltage level to inject renewable energy to DC bus for grid applications. Since the NIC has two circuit branches in parallel at frond end to share input current, it is suitable for high power applications. In addition, the NIC is controlled in an interleaving pattern, which has the advantages that the NIC has lower input current ripple, and the frequency of the ripple is twice the switching frequency. Two coupled inductors and two switched capacitors are incorporated to achieve a much higher voltage gain than conventional high step-up converters. The proposed NIC has intrinsic features such as leakage energy totally recycling and low voltage stress on power semiconductor. Thorough theoretical analysis and key parameter design are presented in this paper. A prototype is built for practical measurements to validate the proposed NIC.

  19. Evaluation of higher distribution and/or utilization voltages. Fourth interim report (August 1980): assessment of optimum distribution configuration

    Energy Technology Data Exchange (ETDEWEB)

    1981-04-01

    This interim report provides documentation on the fourth task, Assessment of Optimum Distribution Configuration, of DOE Contract No. ET-78-C-01-2866, Evaluation of Higher Distribution and/or Utilization Voltages. The work performed under this task includes the development of a computer model for assessment of life cycle costs for the distribution and utilization systems, the development of an optimization algorithm to enable distribution system configuration optimization and a net energy analysis to determine potential net energy savings. Input data for this task derive from Task 3. The major output of this task is a documented computer code.

  20. A New High Frequency Injection Method Based on Duty Cycle Shifting without Maximum Voltage Magnitude Loss

    DEFF Research Database (Denmark)

    Wang, Dong; Lu, Kaiyuan; Rasmussen, Peter Omand

    2015-01-01

    The conventional high frequency signal injection method is to superimpose a high frequency voltage signal to the commanded stator voltage before space vector modulation. Therefore, the magnitude of the voltage used for machine torque production is limited. In this paper, a new high frequency...

  1. 76 FR 19698 - Safety Zone; Repair of High Voltage Transmission Lines to Logan International Airport, Saugus...

    Science.gov (United States)

    2011-04-08

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Repair of High Voltage Transmission Lines..., within the Captain of the Port (COTP) Boston Zone to allow for repair of high voltage transmission lines... during the repair of high voltage transmission lines. Entering into, transiting through, mooring or...

  2. 76 FR 4575 - Safety Zone; Repair of High Voltage Transmission Lines to Logan International Airport, Saugus...

    Science.gov (United States)

    2011-01-26

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AAOO Safety Zone; Repair of High Voltage Transmission Lines... of high voltage transmission lines to Logan Airport. This safety zone is required to provide for the safety of life on navigable waters during the repair of high voltage transmission lines. Entering into...

  3. 30 CFR 75.705-10 - Tying into energized high-voltage surface circuits.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Tying into energized high-voltage surface....705-10 Tying into energized high-voltage surface circuits. If the work of forming an additional circuit by tying into an energized high-voltage surface line is performed from the ground, any person...

  4. 21 CFR 892.1700 - Diagnostic x-ray high voltage generator.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Diagnostic x-ray high voltage generator. 892.1700... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1700 Diagnostic x-ray high voltage generator. (a) Identification. A diagnostic x-ray high voltage generator is a device that is intended to...

  5. 30 CFR 77.704-10 - Tying into energized high-voltage surface circuits.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Tying into energized high-voltage surface... AREAS OF UNDERGROUND COAL MINES Grounding § 77.704-10 Tying into energized high-voltage surface circuits. If the work of forming an additional circuit by tying into an energized high-voltage surface line is...

  6. 30 CFR 75.705-1 - Work on high-voltage lines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Work on high-voltage lines. 75.705-1 Section 75... AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Grounding § 75.705-1 Work on high-voltage lines. (a) Section 75.705 specifically prohibits work on energized high-voltage lines underground; (b...

  7. An evaluation of options to mitigate voltage rise due to increasing PV penetration in distribution networks

    Directory of Open Access Journals (Sweden)

    Carter Craig E.

    2017-01-01

    Full Text Available Australia and most other countries are adopting renewable energy generation as the dominant means of reducing dependence on fossil fuels. This has been made more feasible by the exponential take-up of solar photovoltaic (PV systems and their concurrent production scale-up and cost decline. Rooftop solar PV, combined with battery storage, seems likely to be the dominant means of providing household electricity needs. In response to the technical challenges from rooftop PV, network utilities have implemented various low cost options to cope with PV’s impact on network voltages. However, if we want this clean energy technology to fully utilise the available roof space and eventually meet residential electricity needs, additional hardware, control and commercial options will need to be adopted by both network utilities and their customers to overcome the technical barriers, especially voltage rise. This paper presents the authors’ evaluations of options to mitigate voltage rise, including operating solar inverters with reactive power absorption (var absorbing, dependent only on solar power output or operating the solar inverters in a volt–var response mode (voltage droop control where the inverter adjusts its reactive power (Q in response to changes in its terminal voltage – Q(V. This paper also considers the fulltime Q(V option, where an inverter’s reactive power capacity is independent of solar conditions – statcom mode. The network utility option of using line drop compensation (LDC – used on long rural MV feeders on urban MV feeders during daylight hours is assessed to lessen voltage rise on LV feeders with low net loading or reverse power flow due to high solar PV generation. The paper concludes that a combination of solar inverters performing fast fulltime voltage droop control outside a voltage deadband (statcom mode and HV/MV substation transformers with slow acting daytime LDC mitigates voltage rise, whilst limiting feeder

  8. Pollution Maintenance Techniques in Coastal High Voltage Installations

    Directory of Open Access Journals (Sweden)

    E. Pyrgioti

    2011-02-01

    Full Text Available Pollution of outdoor high voltage insulators is a common problem for utilities, with a considerable impact to power system reliability. In an effort to prevent possible flashovers due to pollution, many methods have been applied, aiming to improve the insulation performance, either by suppressing the formation of surface conductivity or by increasing the possible insulation level. In the case of substations, the selection of the appropriate technique is complex due to certain issues correlated to the nature of the installation. In this paper, several techniques usually implemented by utilities, are investigated based on the experienced gained in the case of Crete, a Greek island in southern Europe, where due to the coastal development of the power system, the majority of high voltage installations are exposed to intense marine pollution. The technique of coating insulators with Room Temperature Vulcanized Silicone Rubber (RTV SIR has proved rather efficient and therefore is presented extendedly. Correlation of the material behaviour with environmental conditions is discussed and results from long term monitoring, including environmental parameters and leakage current measurements, in a 150 kV Substation are presented. It is shown that RTV SIR coatings have remarkably suppressed surface activity and that porcelain insulators exhibit different activity period when coated.

  9. High-Speed Fuses in IGBT based Voltage Source Converters

    DEFF Research Database (Denmark)

    Iov, Florin; Blaabjerg, Frede; Rasmussen, Henrik

    2005-01-01

    The demand for protection of power electronic applications has during the last couple of years increased regarding the high-power IGBT modules. Even with an active protection, a high power IGBT still has a risk of exhibiting a violent rupture in the case of a fault if IGBT fuses do not protect it....... By introducing fuses into voltage source converters a better protection of IGBTs can be achieved. This paper is a complete overview of a research project carried out in cooperation by Aalborg University, Denmark and Cooper Bussmann International. This paper discusses three main issues regarding the IGBT fuse...... protection. First, the problem of adding inductance in the DC-link circuit is treated, second a short discussion of the protection of the IGBT module is done, and finally, the impact of the high frequency loading on the current carrying capability of the fuses is presented....

  10. 30 CFR 77.704-2 - Repairs to energized high-voltage lines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Repairs to energized high-voltage lines. 77.704... UNDERGROUND COAL MINES Grounding § 77.704-2 Repairs to energized high-voltage lines. An energized high-voltage... repairs will be performed on power circuits with a phase-to-phase nominal voltage no greater than 15,000...

  11. ANALYSIS OF GRID-CONNECTED PHOTOVOLTAIC SYSTEM INTEGRATON ON LOW-VOLTAGE DISTRIBUTION NETWORK

    Directory of Open Access Journals (Sweden)

    NEMES C.

    2016-03-01

    Full Text Available The introduction of new local sources on the distribution network will impact the quality of power in different ways. The low-voltage customers are strongly affected by the level of power quality, especially by harmonic distortions. In present paper, the impact on the power quality of a low-voltage utility network with an integrated PV system has been assessed at the point of common coupling of the PV system. In this order, the most representative power quality indices concerning the harmonic distortion have been monitored and compared with the limits set by the corresponding standards.

  12. Modeling and Control of Low Voltage Flexible Units for Enhanced Operation of Distribution Feeders

    DEFF Research Database (Denmark)

    Raboni, Pietro; Hu, Weihao; Chaudhary, Sanjay

    2013-01-01

    Battery (EVB) is proposed for providing primary regulation in grid connected mode and for hierarchically manage an islanded LV distribution feeder. The unit models are described and a novel EVB model directly based on manufacturer’s data is proposed and evaluated comparing its performances with Sim......PowerSystems library block. Moreover a voltage dependant power term is applied to the Voltage-Source Converter (VSC) control scheme of the EVB for improving the performances of the islanded feeder. The control is tested in case of under frequency and consequent load shedding occurring at the residential feeder...

  13. The High Voltage Line Becomes a Power Distributor: A Successful Test in Congo Brazzaville

    Directory of Open Access Journals (Sweden)

    A. Omboua

    2006-03-01

    Full Text Available The high line voltage passes over the head but we don’t have electricity to have our mill functioned, we continue to live without the power! In many developing countries, we have a lot of high lines voltage which cross many regions to supply electricity to the main towns or connect to networks the distanced electric stations.These booked lines for supplying electricity to big towns cross a lot of villages whose people broadly poor hope to be supplied with electricity without a suitable solution. However it seems very deplorable that the power conducted by these lines doesn’t profit to surrounding population. Unfortunately, for these villages, the use of classical stations is too expensive to the power distributors because of high cost of investment and production for these potential scattered consumers with the feeble demand of electricity.This paper presents the original solution, settled in 2002 in one of the village located in Congo Brazzaville, and continues to function correctly. It is a new power transformer with one phase called PLX which is connected on one phase of the high line voltage 220kV and which produces extraordinary the low voltage 230 V directly useful by the rural population. This conceived sample for the rural electrification has been dimensioned for the power of 50kVA. A cheap and resistant advice! It requires a large popularization and mainly in sub saharian Africa that has got many opportunities. Outside the role of conduction of the power, the high line voltage distributes it

  14. High precision, low disturbance calibration of the High Voltage system of the CMS Barrel Electromagnetic Calorimeter

    CERN Document Server

    Marzocchi, Badder

    2017-01-01

    The CMS Electromagnetic Calorimeter is made of scintillating lead tungstate crystals, using avalanche photodiodes (APD) as photo-detectors in the barrel part. The high voltage system, consisting of 1224 channels, biases groups of 50 APD pairs, each at a voltage of about 380 V. The APD gain dependence on the voltage is 3pct/V. A stability of better than 60 mV is needed to have negligible impact on the calorimeter energy resolution. Until 2015 manual calibrations were performed yearly. A new calibration system was deployed recently, which satisfies the requirement of low disturbance and high precision. The system is discussed in detail and first operational experience is presented.

  15. Understanding and Prevention of Transient Voltages and Dielectric Breakdown in High Voltage Battery Systems

    Science.gov (United States)

    2017-07-31

    other provision of law , no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a...in high current battery systems and how vented Li-ion electrolyte gas impacts the dielectric breakdown strength of ambient air. 1S. SUBJECTTERMS...electrical grid, either in homes or in the distribution network, but the loads being sourced in those applications are vastly different than those being

  16. Study of flow behavior in all-vanadium redox flow battery using spatially resolved voltage distribution

    Science.gov (United States)

    Bhattarai, Arjun; Wai, Nyunt; Schweiss, Rüdiger; Whitehead, Adam; Scherer, Günther G.; Ghimire, Purna C.; Nguyen, Tam D.; Hng, Huey Hoon

    2017-08-01

    Uniform flow distribution through the porous electrodes in a flow battery cell is very important for reducing Ohmic and mass transport polarization. A segmented cell approach can be used to obtain in-situ information on flow behaviour, through the local voltage or current mapping. Lateral flow of current within the thick felts in the flow battery can hamper the interpretation of the data. In this study, a new method of segmenting a conventional flow cell is introduced, which for the first time, splits up both the porous felt as well as the current collector. This dual segmentation results in higher resolution and distinct separation of voltages between flow inlet to outlet. To study the flow behavior for an undivided felt, monitoring the OCV is found to be a reliable method, instead of voltage or current mapping during charging and discharging. Our approach to segmentation is simple and applicable to any size of the cell.

  17. A high voltage asymmetric waveform generator for FAIMS.

    Science.gov (United States)

    Canterbury, Jesse D; Gladden, James; Buck, Lon; Olund, Roy; MacCoss, Michael J

    2010-07-01

    High field asymmetric waveform ion mobility spectrometry (FAIMS) has been used increasingly in recent years as an additional method of ion separation and selection before mass spectrometry. The FAIMS electrodes are relatively simple to design and fabricate for laboratories wishing to implement their own FAIMS designs. However, construction of the electronics apparatus needed to produce the required high magnitude asymmetric electric field oscillating at a frequency of several hundred kilohertz is not trivial. Here we present an entirely custom-built electronics setup capable of supplying the required waveforms and voltages. The apparatus is relatively simple and inexpensive to implement. We also present data acquired on this system demonstrating the use of FAIMS as a gas-phase ion filter interface to an ion trap mass spectrometer. Copyright 2010 American Society for Mass Spectrometry. Published by Elsevier Inc. All rights reserved.

  18. High-voltage atmospheric breakdown across intervening rutile dielectrics.

    Energy Technology Data Exchange (ETDEWEB)

    Williamson, Kenneth Martin; Simpson, Sean; Coats, Rebecca Sue; Jorgenson, Roy Eberhardt; Hjalmarson, Harold Paul; Pasik, Michael Francis

    2013-09-01

    This report documents work conducted in FY13 on electrical discharge experiments performed to develop predictive computational models of the fundamental processes of surface breakdown in the vicinity of high-permittivity material interfaces. Further, experiments were conducted to determine if free carrier electrons could be excited into the conduction band thus lowering the effective breakdown voltage when UV photons (4.66 eV) from a high energy pulsed laser were incident on the rutile sample. This report documents the numerical approach, the experimental setup, and summarizes the data and simulations. Lastly, it describes the path forward and challenges that must be overcome in order to improve future experiments for characterizing the breakdown behavior for rutile.

  19. Unique Power Dense, Configurable, Robust, High-Voltage Power Supplies Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Princeton Power will develop and deliver three small, lightweight 50 W high-voltage power supplies that have a configurable output voltage range from 500 to 50 kVDC....

  20. 75 FR 17529 - High-Voltage Continuous Mining Machine Standard for Underground Coal Mines

    Science.gov (United States)

    2010-04-06

    ... condition occurs. Ungrounded circuits include high-voltage transformers that power low- and medium-voltage... transformers in the power center. This will provide a safe means of de-energizing high-voltage circuits in the... machines in underground coal mines. It also revises MSHA's design requirements for approval of these mining...

  1. Battery powered high output voltage bidirectional flyback converter for cylindrical DEAP actuator

    DEFF Research Database (Denmark)

    Huang, Lina; Thummala, Prasanth; Zhang, Zhe

    2012-01-01

    DEAP (Dielectric Electro Active Polymer) actuator is essentially a capacitive load and can be applied in various actuation occasions. However, high voltage is needed to actuate it. In this paper, a high voltage bidirectional flyback converter with low input voltage is presented. The fundamental...

  2. On-load Tap Changer Diagnosis on High-Voltage Power Transformers using Dynamic Resistance Measurements

    NARCIS (Netherlands)

    Erbrink, J.J.

    2011-01-01

    High-voltage transformers have tap changers to regulate the voltage in the high-voltage network when the load changes. Those tap changers are subject to different degradation mechanisms and need regular maintenance. Various defects, like contact degradation, often remain undetected and the

  3. 30 CFR 57.12071 - Movement or operation of equipment near high-voltage powerlines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Movement or operation of equipment near high-voltage powerlines. 57.12071 Section 57.12071 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION...-voltage powerlines. When equipment must be moved or operated near energized high-voltage powerlines (other...

  4. 30 CFR 56.12071 - Movement or operation of equipment near high-voltage power lines.

    Science.gov (United States)

    2010-07-01

    ...-voltage power lines. 56.12071 Section 56.12071 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... NONMETAL MINES Electricity § 56.12071 Movement or operation of equipment near high-voltage power lines. When equipment must be moved or operated near energized high-voltage powerlines (other than trolley...

  5. IEDF distortion and resolution considerations for RFEA operation at high voltages

    Science.gov (United States)

    Talley, M. L.; Shannon, S.; Chen, L.; Verboncoeur, J. P.

    2017-12-01

    Retarding field energy analyzers (RFEA) have been used extensively to measure the ion flux energy distribution function of plasmas. For consistency, the ion flux energy distribution function is referred to as the ion energy distribution function (IEDf) even though it more accurately represents the one-dimensional ion velocity distribution function. In the past, these devices have operated at voltages less than 1 kV. Higher operating voltages (>2 kV) are currently desired. For an RFEA to operate at these voltages, design changes are necessary that impact the energy resolution and cause space charge build-up. To investigate the effect the design changes have for a high voltage RFEA, electromagnetic simulations and particle-in-cell (PIC) simulations were used to analyze the electric field between the grids, the potential drop in the grid holes, and space charge build-up between the grids. Non-unique optimized dimensions for the RFEA increased the electric field uniformity. The optimization minimizes the electric field from distorting the IV curve or adversely affecting the energy resolution. It was found that a larger grid gap distance and smaller grid hole diameter decreases the potential drop in the grid holes improving energy resolution. IV curves from the PIC simulation were used to obtain space charge distorted IEDfs. The point at which space charge distorts the IV curve is dependent on the grid gap distance and incoming flux. Space charge build-up was found to only affect low energy ions which manifested by cutting off the low energy portion of the IEDf. To fix space charge distortions, the flux into the probe can be limited or it may be possible to account for the distortion when calculating the IEDf.

  6. Simulation on Temperature and Ampacity of Mining Flame-proof High Voltage Cable Connector

    Directory of Open Access Journals (Sweden)

    Li Haiying

    2017-01-01

    Full Text Available To investigate the accident causes of mining flame-proof high voltage (F-HV cable connector, the temperature and ampacity of LBG1-200/6 high voltage cable connector are analyzed. At first, the material properties and structure of connector are introduced from the aspects of electrical, insulation and thermal. Then the electromagnetic field and thermal field coupling model of cable connector are established by the finite element method. Finally, in the numerical examples, temperature distribution and ampacity change caused by power harmonics, dielectric loss and slight structure change are quantitatively plotted and analyzed. The paper provides great insight into the security operation of F-HV cable connector.

  7. Electric field analysis of extra high voltage (EHV) underground cables using finite element method

    DEFF Research Database (Denmark)

    Kumar, Mantosh; Bhaskar, Mahajan Sagar; Padmanaban, Sanjeevikumar

    2017-01-01

    Transmission and Distribution of electric power through underground cables is a viable alternative to overhead lines, particularly in residential or highly populated areas. The electrical stresses are consequences of regular voltages and over voltages and the thermal stresses are related to heat...... produced inside the conductor due to flow of high rated current which is the main factors that affect its reliability. The performance of these underground power cables is important for proper operation of the power system. Long-term problems with them are related to the degradation of polymer materials...... used for the insulator due electrical, thermal or environmental stress. Most of these problems are related to the electric field stress on the insulation of the underground cables. The objective of the electric field analysis by using different numerical techniques is to find electric field stress...

  8. Simulation Model solves exact the Enigma named Generating high Voltages and high Frequencies by Tesla Coil

    Directory of Open Access Journals (Sweden)

    Simo Janjanin

    2016-11-01

    Full Text Available Simulation model of Tesla coil has been successfully completed, and has been verified the procedure and functioning. The literature and documentation for the model were taken from the rich sources, especially the copies of Tesla patents. The oscillating system‟s electrical scheme consists of the voltage supply 220/50 Hz, Fe transformer, capacitor and belonging chosen electrical components, the air gap in the primary Tesla coil (air transformer and spark gap in the exit of the coil. The investigation of the oscillating process Tesla coil‟s system using the simulation model in MATLAB & SIMULINK have given the exact solution the enigma named the generating high voltage and high frequency the Tesla‟s coil. The inductance voltage from the spark current in the primary (coil with its high voltage impulse excites the oscillating series circuit Ce-L3-R3 on the secondary of the air transformer to its own damped oscillations

  9. Understanding and Improving High Voltage Vacuum Insulators for Microsecond Pulses

    Energy Technology Data Exchange (ETDEWEB)

    Javedani, J B; Goerz, D A; Houck, T L; Lauer, E J; Speer, R D; Tully, L K; Vogtlin, G E; White, A D

    2007-03-05

    High voltage insulation is one of the main areas of pulsed power research and development, and dielectric breakdown is usually the limiting factor in attaining the highest possible performance in pulsed power devices. For many applications the delivery of pulsed power into a vacuum region is the most critical aspect of operation. The surface of an insulator exposed to vacuum can fail electrically at an applied field more than an order or magnitude below the bulk dielectric strength of the insulator. This mode of breakdown, called surface flashover, imposes serious limitations on the power flow into a vacuum region. This is especially troublesome for applications where high voltage conditioning of the insulator and electrodes is not practical and for applications where relatively long pulses, on the order of several microseconds, are required. The goal of this project is to establish a sound fundamental understanding of the mechanisms that lead to surface flashover, and then evaluate the most promising techniques to improve vacuum insulators and enable high voltage operation at stress levels near the intrinsic bulk breakdown limits of the material. The approach we proposed and followed was to develop this understanding through a combination of theoretical and computation methods coupled with experiments to validate and quantify expected behaviors. In this report we summarize our modeling and simulation efforts, theoretical studies, and experimental investigations. The computational work began by exploring the limits of commercially available codes and demonstrating methods to examine field enhancements and defect mechanisms at microscopic levels. Plasma simulations with particle codes used in conjunction with circuit models of the experimental apparatus enabled comparisons with experimental measurements. The large scale plasma (LSP) particle-in-cell (PIC) code was run on multiprocessor platforms and used to simulate expanding plasma conditions in vacuum gap regions

  10. Hybrid-PIC Modeling of a High-Voltage, High-Specific-Impulse Hall Thruster

    Science.gov (United States)

    Smith, Brandon D.; Boyd, Iain D.; Kamhawi, Hani; Huang, Wensheng

    2013-01-01

    The primary life-limiting mechanism of Hall thrusters is the sputter erosion of the discharge channel walls by high-energy propellant ions. Because of the difficulty involved in characterizing this erosion experimentally, many past efforts have focused on numerical modeling to predict erosion rates and thruster lifespan, but those analyses were limited to Hall thrusters operating in the 200-400V discharge voltage range. Thrusters operating at higher discharge voltages (V(sub d) >= 500 V) present an erosion environment that may differ greatly from that of the lower-voltage thrusters modeled in the past. In this work, HPHall, a well-established hybrid-PIC code, is used to simulate NASA's High-Voltage Hall Accelerator (HiVHAc) at discharge voltages of 300, 400, and 500V as a first step towards modeling the discharge channel erosion. It is found that the model accurately predicts the thruster performance at all operating conditions to within 6%. The model predicts a normalized plasma potential profile that is consistent between all three operating points, with the acceleration zone appearing in the same approximate location. The expected trend of increasing electron temperature with increasing discharge voltage is observed. An analysis of the discharge current oscillations shows that the model predicts oscillations that are much greater in amplitude than those measured experimentally at all operating points, suggesting that the differences in oscillation amplitude are not strongly associated with discharge voltage.

  11. Investigating Enhancement Mode Gallium Nitride Power FETs in High Voltage, High Frequency Soft Switching Converters

    DEFF Research Database (Denmark)

    Nour, Yasser; Knott, Arnold; Jørgensen, Ivan Harald Holger

    2016-01-01

    of using enhancement mode gallium nitride switches to form a 50V quasi-square-wave zero-voltage-switching buck converter running at 2-6 MHz under full load. The designed converter achieved 83% efficiency converting 50V input voltage to 12.2V at 9W load.......An increased attention has been detected to develop smaller and lighter high voltage power converters in the range of 50V to 400V domain. The main applications for these converters are mainly focused for Power over Ethernet (PoE), LED lighting and AC adapters. This work will discuss a study...

  12. Investigating Enhancement Mode Gallium Nitride Power FETs in High Voltage, High Frequency Soft Switching Converters

    DEFF Research Database (Denmark)

    Nour, Yasser; Knott, Arnold; Jørgensen, Ivan Harald Holger

    2016-01-01

    An increased attention has been detected to develop smaller and lighter high voltage power converters in the range of 50V to 400V domain. The main applications for these converters are mainly focused for Power over Ethernet (PoE), LED lighting and AC adapters. This work will discuss a study of us...... of using enhancement mode gallium nitride switches to form a 50V quasi-square-wave zero-voltage-switching buck converter running at 2-6 MHz under full load. The designed converter achieved 83% efficiency converting 50V input voltage to 12.2V at 9W load....

  13. The Simulation Study of a Restructured Residential Low-Voltage Distribution System Microgrid

    Directory of Open Access Journals (Sweden)

    L. Ramesh

    2016-12-01

    Full Text Available A primary and necessary focus in creating a greener environment is the conversion of existing power-generation sources to renewable power sources in the near future. Another important focus is to develop sustainable household power generation to a low-voltage electricity grid with a power purchase and selling facility. To help with achieving the above vision, the objective of this work is to critically analyze the existing low-voltage distribution system and make suggestions for restructuring it to the low-voltage interconnected microgrid (MG. The test was carried out in the Tamil Nadu Electricity Board (TNEB 100kVA transformer feeder which was connected to supply around 100 houses with electricity. The performance analysis of the proposed system was examined through different case studies, represented as a normal operating condition of the existing distribution system and a reconstructed and interconnected MG to the TNEB grid. The project was designed and analyzed using PSCAD software. The results discussed in the project are helpful in examining the effects of multiple distributed energy resources on distributed generation. In future, knowledge of these effects may be helpful for rural area electrification.

  14. Electric and magnetic field measurements in a high voltage center.

    Science.gov (United States)

    Safigianni, Anastasia S; Spyridopoulos, Anastasios I; Kanas, Vasilis L

    2012-01-01

    This paper investigates the electric and magnetic fields inside a large high voltage center constituted both of 400/150 and 150/20 kV substation areas. Results of previous field measurements and calculations in substations, made by the authors of this paper or other researchers, are presented first. The basic data distinguishing the examined center from previously examined substations follow. The main results of the field measurements in the areas of the above-mentioned center are presented in relevant diagrams. General conclusions arising from the comparison of the measured field values with relevant reference levels in force for safe public and occupational exposure as well as with the results of previous research are finally given.

  15. High Voltage Installation of PS Linac 1 Preinjector

    CERN Multimedia

    CERN PhotoLab

    1974-01-01

    The high-voltage installation of the linac 1 preinjector in its house-sized Faraday cage. Originally driven by a 520 kV Cockcroft-Walton generator, at the time of this picture the HV came from a 520 kV SAMES generator. The column in the front carries a capacitor. The cubicle in the right background is the electronics platform (see 7403120). The round structure at left houses the ion source, from where the protons (and sometimes other ions), electrostatically accelerated to 520 keV, enter the Alvarez structure of linac 1, to be accelerated to 50 MeV. Jean-Luc Vallet is busy with servicing the installation. See also 7403064X, 7403066X.

  16. Growing of semiinsulating Si for high-voltage devices

    Directory of Open Access Journals (Sweden)

    Turtsevich A. S.

    2008-02-01

    Full Text Available The effect of the N2O/SiH4 flow ratio ( on the peculiarities of initial stages, structural, morphological and electrophysical properties of the SiPOS film has been investigates. The average roughness of thin SiPOS films (Ra is 0.09 nm (for polysilicon films - 1.52 nm. The films having 2.5-22.0 at.% oxygen have quasi-crystal structure. Explanation of the obtained results on the base of multi-route layer deposition process in SiH4-N2O gas system has been presented. The obtained results have been used for the optimization of SiPOS film deposition process under high-voltage device.

  17. Push-pull with recovery stage high-voltage DC converter for PV solar generator

    Science.gov (United States)

    Nguyen, The Vinh; Aillerie, Michel; Petit, Pierre; Pham, Hong Thang; Vo, Thành Vinh

    2017-02-01

    A lot of systems are basically developed on DC-DC or DC-AC converters including electronic switches such as MOS or bipolar transistors. The limits of efficiency are quickly reached when high output voltages and high input currents are needed. This work presents a new high-efficiency-high-step-up based on push-pull DC-DC converter integrating recovery stages dedicated to smart HVDC distributed architecture in PV solar energy production systems. Appropriate duty cycle ratio assumes that the recovery stage work with parallel charge and discharge to achieve high step-up voltage gain. Besides, the voltage stress on the main switch is reduced with a passive clamp circuit and thus, low on-state resistance Rdson of the main switch can be adopted to reduce conduction losses. Thus, the efficiency of a basic DC-HVDC converter dedicated to renewable energy production can be further improved with such topology. A prototype converter is developed, and experimentally tested for validation.

  18. Architecture for a High-to-Medium-Voltage Power Converter

    Science.gov (United States)

    Vorpenian, Vatche

    2008-01-01

    A power converter now undergoing development is required to operate at a DC input potential ranging between 5.5 and 10 kV and a DC output potential of 400 V at a current up to 25 A. This power converter is also required to be sufficiently compact and reliable to fit and operate within the confines of a high-pressure case to be lowered to several miles (approx.5 km) below the surface of the ocean. The architecture chosen to satisfy these requirements calls for a series/ parallel arrangement of 48 high-frequency, pulse-width-modulation (PWM), transformer-isolation DC-to-DC power converter blocks. The input sides of the converter blocks would be connected in series so that the input potential would be divided among them, each of them being exposed to an input potential of no more than 10 kV/48 . 210 V. The series connection of inputs would also enforce a requirement that all the converter blocks operate at the same input current. The outputs of the converter blocks would be connected in a matrix comprising 6 parallel legs, each leg being a cascade of eight outputs wired in series (see figure). All the converter blocks would be identical within the tolerances of the values of their components. A single voltage feedback loop would regulate the output potential. All the converter blocks would be driven by the same PWM waveform generated by this feedback loop. The power transformer of each converter block would have a unity turns ratio and would be capable of withstanding as much as 10 kVDC between its primary and secondary windings. (Although, in general, the turns ratio could be different from unity, the simplest construction for minimizing leakage and maximizing breakdown voltage is attained at a turns ratio of unity.)

  19. DISTRIBUTION NETWORK RECONFIGURATION FOR POWER LOSS MINIMIZATION AND VOLTAGE PROFILE ENHANCEMENT USING ANT LION ALGORITHM

    Directory of Open Access Journals (Sweden)

    Maryam Shokouhi

    2017-06-01

    Full Text Available Distribution networks are designed as a ring and operated as a radial form. Therefore, the reconfiguration is a simple and cost-effective way to use existing facilities without the need for any new equipment in distribution networks to achieve various objectives such as: power loss reduction, feeder overload reduction, load balancing, voltage profile improvement, reducing the number of switching considering constraints that ultimately result in the power loss reduction. In this paper, a new method based on the Ant Lion algorithm (a modern meta-heuristic algorithm is provided for the reconfiguration of distribution networks. Considering the extension of the distribution networks and complexity of their communications networks, and the various parameters, using smart techniques is inevitable. The proposed approach is tested on the IEEE 33 & 69-bus radial standard distribution networks. The Evaluation of results in MATLAB software shows the effectiveness of the Ant Lion algorithm in the distribution network reconfiguration.

  20. First high-voltage measurements using Ca+ ions at the ALIVE experiment

    Science.gov (United States)

    König, K.; Geppert, Ch.; Krämer, J.; Maaß, B.; Otten, E. W.; Ratajczyk, T.; Nörtershäuser, W.

    2017-11-01

    Many physics experiments depend on accurate high-voltage measurements to determine for example the exact retardation potential of an electron spectrometer as in the KATRIN experiment or the acceleration voltage of the ions at ISOL facilities. Until now only precision high-voltage dividers can be used to measure voltages up to 65 kV with an accuracy of 1 ppm. However, these dividers need frequent calibration and cross-checking and the direct traceability is not given. In this article we will describe the status of an experiment which aims to measure high voltages using collinear laser spectroscopy and which has the potential to provide a high-voltage standard and hence, a calibration source for precision high-voltage dividers on the 1 ppm level.

  1. First high-voltage measurements using Ca{sup +} ions at the ALIVE experiment

    Energy Technology Data Exchange (ETDEWEB)

    König, K., E-mail: kkoenig@ikp.tu-darmstadt.de [Technische Universität Darmstadt, Institut für Kernphysik (Germany); Geppert, Ch. [Universität Mainz, Institut für Kernchemie (Germany); Krämer, J.; Maaß, B. [Technische Universität Darmstadt, Institut für Kernphysik (Germany); Otten, E. W. [Universität Mainz, Institut für Physik (Germany); Ratajczyk, T.; Nörtershäuser, W. [Technische Universität Darmstadt, Institut für Kernphysik (Germany)

    2017-11-15

    Many physics experiments depend on accurate high-voltage measurements to determine for example the exact retardation potential of an electron spectrometer as in the KATRIN experiment or the acceleration voltage of the ions at ISOL facilities. Until now only precision high-voltage dividers can be used to measure voltages up to 65 kV with an accuracy of 1 ppm. However, these dividers need frequent calibration and cross-checking and the direct traceability is not given. In this article we will describe the status of an experiment which aims to measure high voltages using collinear laser spectroscopy and which has the potential to provide a high-voltage standard and hence, a calibration source for precision high-voltage dividers on the 1 ppm level.

  2. High voltage and high specific capacity dual intercalating electrode Li-ion batteries

    Science.gov (United States)

    West, William C. (Inventor); Blanco, Mario (Inventor)

    2010-01-01

    The present invention provides high capacity and high voltage Li-ion batteries that have a carbonaceous cathode and a nonaqueous electrolyte solution comprising LiF salt and an anion receptor that binds the fluoride ion. The batteries can comprise dual intercalating electrode Li ion batteries. Methods of the present invention use a cathode and electrode pair, wherein each of the electrodes reversibly intercalate ions provided by a LiF salt to make a high voltage and high specific capacity dual intercalating electrode Li-ion battery. The present methods and systems provide high-capacity batteries particularly useful in powering devices where minimizing battery mass is important.

  3. Distributed Low Voltage Ride-Through Operation of Power Converters in Grid-Connected Microgrids under Voltage Sags

    DEFF Research Database (Denmark)

    Zhao, Xin; Meng, Lexuan; Dragicevic, Tomislav

    2015-01-01

    it can make the MG a contributor in smooth ride through the faults. In this paper, a reactive power support strategy using droop controlled converters is proposed to aid MG riding through three phase symmetrical voltage sags. In such a case, the MGs should inject reactive power to the grid to boost...... the voltage in all phases at AC common bus. However, since the line admittances from each converter to point of common coupling (PCC) are not identical, the injected reactive power may not be equally shared. In order to achieve low voltage ride through (LVRT) capability along with a good power sharing...

  4. High-Voltage-Input Level Translator Using Standard CMOS

    Science.gov (United States)

    Yager, Jeremy A.; Mojarradi, Mohammad M.; Vo, Tuan A.; Blalock, Benjamin J.

    2011-01-01

    proposed integrated circuit would translate (1) a pair of input signals having a low differential potential and a possibly high common-mode potential into (2) a pair of output signals having the same low differential potential and a low common-mode potential. As used here, "low" and "high" refer to potentials that are, respectively, below or above the nominal supply potential (3.3 V) at which standard complementary metal oxide/semiconductor (CMOS) integrated circuits are designed to operate. The input common-mode potential could lie between 0 and 10 V; the output common-mode potential would be 2 V. This translation would make it possible to process the pair of signals by use of standard 3.3-V CMOS analog and/or mixed-signal (analog and digital) circuitry on the same integrated-circuit chip. A schematic of the circuit is shown in the figure. Standard 3.3-V CMOS circuitry cannot withstand input potentials greater than about 4 V. However, there are many applications that involve low-differential-potential, high-common-mode-potential input signal pairs and in which standard 3.3-V CMOS circuitry, which is relatively inexpensive, would be the most appropriate circuitry for performing other functions on the integrated-circuit chip that handles the high-potential input signals. Thus, there is a need to combine high-voltage input circuitry with standard low-voltage CMOS circuitry on the same integrated-circuit chip. The proposed circuit would satisfy this need. In the proposed circuit, the input signals would be coupled into both a level-shifting pair and a common-mode-sensing pair of CMOS transistors. The output of the level-shifting pair would be fed as input to a differential pair of transistors. The resulting differential current output would pass through six standoff transistors to be mirrored into an output branch by four heterojunction bipolar transistors. The mirrored differential current would be converted back to potential by a pair of diode-connected transistors

  5. Advances in high voltage insulation and arc interruption in SF6 and vacuum

    CERN Document Server

    Maller, V N

    1982-01-01

    Advances in High Voltage Insulation and Arc Interruption in SF6 and Vacuum deals with high voltage breakdown and arc extinction in sulfur hexafluoride (SF6) and high vacuum, with special emphasis on the application of these insulating media in high voltage power apparatus and devices. The design and developmental aspects of various high voltage power apparatus using SF6 and high vacuum are highlighted. This book is comprised of eight chapters and opens with a discussion on electrical discharges in SF6 and high vacuum, along with the properties and handling of SF6 gas. The following chapters fo

  6. Using the Direct Search Method for Optimal Dispatch of Distributed Generation in a Medium-Voltage Microgrid

    Directory of Open Access Journals (Sweden)

    Wei-Tzer Huang

    2014-12-01

    Full Text Available This paper proposes a simple and efficient approach for the optimal dispatch in a medium-voltage microgrid (MG with various types of distributed generation (DG. The fuel costs generated by these DGs are determined using quadratic and linear functions dependent on the types of DGs. Instead of using the traditional Lagrange multiplier method for power system economic dispatch, the proposed direct search method (DSM approach is able to handle several inequality constraints without introducing any multipliers and furthermore it can solve the non-derivative problems or the fuel cost functions being much more complicated. Accordingly, the DSM is proposed for determining the optimal dispatch of MGs with various types of DG to minimize generation costs under grid-tied and autonomous operations. Results demonstrate that the proposed DSM is a highly suitable and simple approach to determining the optimal dispatch in medium-voltage MGs with various types of DG.

  7. Method and system for a gas tube switch-based voltage source high voltage direct current transmission system

    Energy Technology Data Exchange (ETDEWEB)

    She, Xu; Chokhawala, Rahul Shantilal; Zhou, Rui; Zhang, Di; Sommerer, Timothy John; Bray, James William

    2016-12-13

    A voltage source converter based high-voltage direct-current (HVDC) transmission system includes a voltage source converter (VSC)-based power converter channel. The VSC-based power converter channel includes an AC-DC converter and a DC-AC inverter electrically coupled to the AC-DC converter. The AC-DC converter and a DC-AC inverter include at least one gas tube switching device coupled in electrical anti-parallel with a respective gas tube diode. The VSC-based power converter channel includes a commutating circuit communicatively coupled to one or more of the at least one gas tube switching devices. The commutating circuit is configured to "switch on" a respective one of the one or more gas tube switching devices during a first portion of an operational cycle and "switch off" the respective one of the one or more gas tube switching devices during a second portion of the operational cycle.

  8. Megahertz high voltage pulse generator suitable for capacitive load

    Science.gov (United States)

    Xu, Yu; Chen, Wei; Liang, Hao; Li, Yu-Huai; Liang, Fu-Tian; Shen, Qi; Liao, Sheng-Kai; Peng, Cheng-Zhi

    2017-11-01

    A high voltage pulse generator is presented to drive Pockels cell. The Pockels cell behaves like a capacitor which slows the rise/fall time of the pulse and restrains the repetition rate of the generator. To drive the Pockels cell applied in quantum communication system, it requires about 1 MHz repetition rate with the rise/fall time of the pulse less than 50 ns, adjustable amplitude up to 800 V and an adjustable duration. With the assistance of self-designed transformers, the circuits is simplified that a pair of high current radio frequency (RF) MOSFET drivers are employed to switch the power MOSFETs at a high speed, and the power MOSFETs shape the final output pulse with the requirements. From the tests, the generator can produce 800 V square pulses continously at 1 MHz rate with 46 ns in risetime and 31 ns in falltime when driving a 51 pF capacitive load. And the generator is now used to drive Pockels cell for encoding the polarization of photons.

  9. Megahertz high voltage pulse generator suitable for capacitive load

    Directory of Open Access Journals (Sweden)

    Yu Xu

    2017-11-01

    Full Text Available A high voltage pulse generator is presented to drive Pockels cell. The Pockels cell behaves like a capacitor which slows the rise/fall time of the pulse and restrains the repetition rate of the generator. To drive the Pockels cell applied in quantum communication system, it requires about 1 MHz repetition rate with the rise/fall time of the pulse less than 50 ns, adjustable amplitude up to 800 V and an adjustable duration. With the assistance of self-designed transformers, the circuits is simplified that a pair of high current radio frequency (RF MOSFET drivers are employed to switch the power MOSFETs at a high speed, and the power MOSFETs shape the final output pulse with the requirements. From the tests, the generator can produce 800 V square pulses continously at 1 MHz rate with 46 ns in risetime and 31 ns in falltime when driving a 51 pF capacitive load. And the generator is now used to drive Pockels cell for encoding the polarization of photons.

  10. A VOLTAGE STABILIZER FOR A MICROGRID SYSTEM WITH TWO TYPES OF DISTRIBUTED GENERATION RESOURCES

    Directory of Open Access Journals (Sweden)

    Maedeh Mahzarnia

    2013-11-01

    Full Text Available ABSTRACT: Microgrids are used as controllable units connected to power grid, in which the electrical distances between reactive power sources and the loads that need the reactive compensation are not too much. Thus, a coordinated compensation of reactive sources has to be implemented in order to avoid a fast voltage collapse by proposing a Microgrid Voltage Stabilizer (MGVS. This stabilizer is desirable to improve the dynamic voltage profile and is tested at a 21-bus IEEE microgrid system. In order to verify the performance of this stabilizer, three distributed generation (DG resources are utilized in this microgrid (Two PV resources which are categorized as power-electronic converter based on DG and a diesel generator which is known as synchronous machine-based on DG. At first, the mentioned resources and all of their needed equipments are modeled. Then a control model of the stabilizer with appropriate parameters for the proposed microgrid is presented. Voltage deficiency of the system is the input of the stabilizer, and the output signal of the stabilizer, is divided between the DGs in order to provide required reactive power. The dynamic voltage profile of buses in the presence of MGVS and its absence has been compared by implying disturbances. Simulation results in MATLAB/SIMULINK show that the dynamic voltage profile of the buses improves satisfactorily with the addition of MGVS. ABSTRAK: Grid mikro digunakan sebagai unit kawalan yang disambungkan kepada grid kuasa, di mana jarak elektrikal antara sumber kuasa reaktif dan bebanan yang memerlukan kompensasi reaktif tidak terlalu besar.  Dengan itu, kompensasi yang selaras dengan sumber reaktif perlu diimplimentasikan untuk mengelak kegagalan voltan pantas dengan menggunakan Grid Mikro Penstabil Voltan (Microgrid Voltage Stabilizer - MGVS. Penstabil ini sesuai digunakan untuk meningkatkan profil voltan dinamik dan telah diuji ke atas sistem mikro grid 21-bus IEEE. Untuk memastikan

  11. The Investigation of Field Plate Design in 500 V High Voltage NLDMOS

    Directory of Open Access Journals (Sweden)

    Donghua Liu

    2015-01-01

    Full Text Available This paper presents a 500 V high voltage NLDMOS with breakdown voltage (VBD improved by field plate technology. Effect of metal field plate (MFP and polysilicon field plate (PFP on breakdown voltage improvement of high voltage NLDMOS is studied. The coeffect of MFP and PFP on drain side has also been investigated. A 500 V NLDMOS is demonstrated with a 37 μm drift length and optimized MFP and PFP design. Finally the breakdown voltage 590 V and excellent on-resistance performance (Rsp = 7.88 ohm * mm2 are achieved.

  12. Low voltage main distribution with redundant feeding; Niederspannungshauptverteilung mit redundanter Einspeisung

    Energy Technology Data Exchange (ETDEWEB)

    Schell, Michael [Rittal GmbH und Co. KG, Herborn (Germany). Produktmanagement Power Distribution; Koch, Hans-Robert [Rittal GmbH und Co. KG, Herborn (Germany). Presse- und Oeffentlichkeitsarbeit

    2012-08-15

    Low voltage switching stations for power plants must operate without interruption. Therefore, these switchgears often are built up redundantly. A lignite power plant in Central Europe commissioned the medium-sized company A+H Steuer- und Regeltechnik (Remscheid, Federal Republic of Germany) to build a low-voltage switching station in which the supply redundantly is realized by means of two transformers. The main feeders and the switching network place high demands on design, construction and installation. The complex requirements were fulfilled using the solution kit 'Ri4Power' and the engineering tool 'Power Engineering' from Rittal easily and quickly fulfilled.

  13. Improvement of high-voltage staircase drive circuit waveform for high-intensity therapeutic ultrasound

    Science.gov (United States)

    Tamano, Satoshi; Jimbo, Hayato; Azuma, Takashi; Yoshizawa, Shin; Fujiwara, Keisuke; Itani, Kazunori; Umemura, Shin-Ichiro

    2016-07-01

    Recently, in the treatment of diseases such as cancer, noninvasive or low-invasive modality, such as high-intensity focused ultrasound (HIFU), has been put into practice as an alternative to open surgery. HIFU induces thermal ablation of the target tissue to be treated. To improve the efficiency of HIFU, we have proposed a “triggered-HIFU” technique, which uses the combination of a short-duration, high-voltage transmission and a long-duration, medium-voltage transmission. In this method, the transmission device must endure high peak voltage for the former and the high time-average power for the latter. The triggered-HIFU sequence requires electronic scanning of the HIFU focus to maximize its thermal efficiency. Therefore, the transmission device must drive an array transducer with the number of elements on the order of a hundred or more, which requires that each part of the device that drives each element must be compact. The purpose of this work is to propose and construct such a transmission device by improving the staircase drive circuit, which we previously proposed. The main point of improvement is that both N and P MOSFETs are provided for each staircase voltage level instead of only one of them. Compared with the previous ultrasonic transmission circuit, high-voltage spikes were significantly reduced, the power consumption was decreased by 26.7%, and the transmission circuit temperature rise was decreased by 14.5 °C in the triggered-HIFU heating mode.

  14. Characteristics and Breakdown Behaviors of Polysilicon Resistors for High Voltage Applications

    Directory of Open Access Journals (Sweden)

    Xiao-Yu Tang

    2015-01-01

    Full Text Available With the rapid development of the power integrated circuit technology, polysilicon resistors have been widely used not only in traditional CMOS circuits, but also in the high voltage applications. However, there have been few detailed reports about the polysilicon resistors’ characteristics, like voltage and temperature coefficients and breakdown behaviors which are critical parameters of high voltage applications. In this study, we experimentally find that the resistance of the polysilicon resistor with a relatively low doping concentration shows negative voltage and temperature coefficients, while that of the polysilicon resistor with a high doping concentration has positive voltage and temperature coefficients. Moreover, from the experimental results of breakdown voltages of the polysilicon resistors, it could be deduced that the breakdown of polysilicon resistors is thermally rather than electrically induced. We also proposed to add an N-type well underneath the oxide to increase the breakdown voltage in the vertical direction when the substrate is P-type doped.

  15. Battery Storage Systems as Grid-Balancing Measure in Low-Voltage Distribution Grids with Distributed Generation

    Directory of Open Access Journals (Sweden)

    Bernhard Faessler

    2017-12-01

    Full Text Available Due to the promoted integration of renewable sources, a further growth of strongly transient, distributed generation is expected. Thus, the existing electrical grid may reach its physical limits. To counteract this, and to fully exploit the viable potential of renewables, grid-balancing measures are crucial. In this work, battery storage systems are embedded in a grid simulation to evaluate their potential for grid balancing. The overall setup is based on a real, low-voltage distribution grid topology, real smart meter household load profiles, and real photovoltaics load data. An autonomous optimization routine, driven by a one-way communicated incentive, determines the prospective battery operation mode. Different battery positions and incentives are compared to evaluate their impact. The configurations incorporate a baseline simulation without storage, a single, central battery storage or multiple, distributed battery storages which together have the same power and capacity. The incentives address either market conditions, grid balancing, optimal photovoltaic utilization, load shifting, or self-consumption. Simulations show that grid-balancing incentives result in lowest peak-to-average power ratios, while maintaining negligible voltage changes in comparison to a reference case. Incentives reflecting market conditions for electricity generation, such as real-time pricing, negatively influence the power quality, especially with respect to the peak-to-average power ratio. A central, feed-in-tied storage performs better in terms of minimizing the voltage drop/rise and shows lower distribution losses, while distributed storages attached at nodes with electricity generation by photovoltaics achieve lower peak-to-average power ratios.

  16. Development of high voltage lead wires using electron beam irradiation

    Science.gov (United States)

    Hun-Jai, Bae; Ho-Soung, Sohn; Dong-Jung, Choi

    1995-09-01

    It is known to those skilled to the art that the electric wires used in high voltage operating electric equipments such as TV sets, microwave ovens, duplicators and etc., have such a structure that a conductor is coated with an insulating layer which is encapsulated with a protecting jacket layer. The electric wire specification such as UL and CSA requires superior cut-through property and flame-retardant property of the wire for utilization safety. The cut-through property of insulation material, for example, high density polyethylene, can be increased by crosslinking of the polymer. Also the flame-retardant property of jacket material which protects the flammable inner insulation can be raised by flame-retardant formulating of the material. In the wire and cable industry, crosslinking by electron beam processing is more effective than that by chemical processing in the viewpoint of through-put rate of the products. The jacket layer of the wire plays the role of protecting the insulation material from burning. The protecting ability of the jacket is related to its inherent flammability and formability of swollen carbonated layer when burned. Crosslinking of the material gives a good formability of swollen carbonated layer, and it protects the insulation material from direct flame. In formulating the flame-retardant jacket material, a crosslinking system must be considered with base polymers and other flame-retardant additives.

  17. Photoconductivity of high-voltage space insulating materials

    Science.gov (United States)

    Coffey, H. T.; Nanevicz, J. E.; Adamo, R. C.

    1975-01-01

    The dark and photoconductivities of four high voltage spacecraft insulators, Kapton-H, FEP Teflon, Parylene, and fused quartz, were studied under a variety of conditions intended to simulate a space environment. All measurements were made in a vacuum of less than .00001 torr while the temperature was varied from 22 C to 100 C. Some of the samples used employed conventional deposited metal electrodes--others employed electrodes composed either of an electron beam or a plasma formed by ionization of the residual gas in the test chamber. Test results show: (1) Kapton had unusual conduction properties; it conductivity decreased by more than an order of magnitude when heated at 100 C in a vacuum, but ultimately attained a stable and reproducible value. (2) Both Teflon and fused quartz had high dark resistivities but low photoresistivities when exposed to UV. Optical-density measurements revealed that both materials transmitted UV with little attenuation. (3) Parylene was found to have a low but relatively stable resistivity--comparatively minor changes occurred upon heating or illuminating the sample. Optical-density measurements showed that Parylene was absorbent in the UV and would prevent photoemission from the metal electrode on the back surface.

  18. High breakdown voltage GaN-on-insulator based heterojunction field effect transistor with a partial back barrier layer

    Science.gov (United States)

    Du, Jiangfeng; Li, Ruonan; Bai, Zhiyuan; Liu, Yong; Yu, Qi

    2017-11-01

    A high breakdown voltage GaN-on-Insulator based heterojunction field effect transistor with a partial back barrier (PB-GOI HFET) is proposed in this paper. The partial back barrier (PB) formed by AlGaN is located in the GaN channel layer, which can make the breakdown voltage improved significantly by modulating the distribution of electric field along the channel. PB-GOI HFET can not only maintain the original advantages of GOI structure, but also improve the breakdown voltage without degradation of frequency performance. Compared with a conventional GOI HFET, the proposed PB-GOI HFET with gate-drain distance of 5 μm possesses the breakdown voltage of 1200 V and the FOM of 3.12 GW/cm2, which increased by more than 353% and 976%. The novel PB-GOI HFET shows great prospects in power electronics applications.

  19. BEHAVIOUR OF BACKFILL MATERIALS FOR ELECTRICAL GROUNDING SYSTEMS UNDER HIGH VOLTAGE CONDITIONS

    Directory of Open Access Journals (Sweden)

    S. C. LIM

    2015-06-01

    Full Text Available Backfill materials like Bentonite and cement are effective in lowering grounding resistance of electrodes for a considerable period. During lightning, switching impulses and earth fault occurrences in medium and high voltage networks, the grounding system needs to handle extremely high currents either for a short duration or prolonged period respectively. This paper investigates the behaviour of bentonite, cement and sand under impulse and alternating high voltage (50Hz conditions. Fulguritic-formation was observed in all materials under alternating high voltage. The findings reveal that performance of grounding systems under high voltage conditions may significantly change from the outcomes anticipated at design stage.

  20. Determination of exposure to electric fields in extra high voltage substations.

    Science.gov (United States)

    Lövstrand, K G

    1976-09-01

    Electrophysical effects related to extra high voltage are surveyed for the determination of the exposure of personnel to electric fields in substations. It is concluded that the electric field strengths and the electrical discharges to the personnel are the important electrophysical factors. Instruments for measuring the field strength at grounded surfaces and at nonzero potentials were constructed. Results are presented of measurements with these instruments in substations. A dummy was used for the measurement of the distribution of capacitive currents to a man. The dummy can also be used for measuring the effectiveness of special shielding clothes.

  1. Anatomical distribution of voltage-dependent membrane capacitance in frog skeletal muscle fibers.

    Science.gov (United States)

    Huang, C L; Peachey, L D

    1989-03-01

    Components of nonlinear capacitance, or charge movement, were localized in the membranes of frog skeletal muscle fibers by studying the effect of 'detubulation' resulting from sudden withdrawal of glycerol from a glycerol-hypertonic solution in which the muscles had been immersed. Linear capacitance was evaluated from the integral of the transient current elicited by imposed voltage clamp steps near the holding potential using bathing solutions that minimized tubular voltage attenuation. The dependence of linear membrane capacitance on fiber diameter in intact fibers was consistent with surface and tubular capacitances and a term attributable to the capacitance of the fiber end. A reduction in this dependence in detubulated fibers suggested that sudden glycerol withdrawal isolated between 75 and 100% of the transverse tubules from the fiber surface. Glycerol withdrawal in two stages did not cause appreciable detubulation. Such glycerol-treated but not detubulated fibers were used as controls. Detubulation reduced delayed (q gamma) charging currents to an extent not explicable simply in terms of tubular conduction delays. Nonlinear membrane capacitance measured at different voltages was expressed normalized to accessible linear fiber membrane capacitance. In control fibers it was strongly voltage dependent. Both the magnitude and steepness of the function were markedly reduced by adding tetracaine, which removed a component in agreement with earlier reports for q gamma charge. In contrast, detubulated fibers had nonlinear capacitances resembling those of q beta charge, and were not affected by adding tetracaine. These findings are discussed in terms of a preferential localization of tetracaine-sensitive (q gamma) charge in transverse tubule membrane, in contrast to a more even distribution of the tetracaine-resistant (q beta) charge in both transverse tubule and surface membranes. These results suggest that q beta and q gamma are due to different molecules and that

  2. An evaluation of high voltage cable-coupler performance for underground mine power systems

    Energy Technology Data Exchange (ETDEWEB)

    Bise, C.; Morley, L.A.

    1982-07-01

    High voltage cable couplers are convenient and widely used accessories in modern coal-mine power distribution systems for aiding in the extension and retraction of power-feeder cables throughout a mine. Coupler design has tried to keep pace with the industry's desire to move to higher distribution levels, but the increase in recorded failures of 15 kV-class couplers, which serve the distribution levels of 12.47 kV and above, have inhibited this transition. The problems associated with high-voltage cable couplers are analyzed. Manufacturing, testing, and mounting practices are reviewed. A discussion of a coupler's operating environment is also included. On the basis of the aforementioned conditions, a testing standard is developed and various coupler designs are subjected to its requirements. An analysis of the test results is provided. Although new couplers can satisfy the performance requirements of the cables to which they are mounted, partial discharge appears to be the failure mechanism of concern. The effects of partial discharge are magnified where voids, either in the insulation, cable termination, or potting compound, occur. In this regard, it is shown that the quality of installation of a coupler onto cable is quite critical. By slightly altering the mounting procedure satisfactory partial-discharge readings are produced on a test coupler.

  3. A compact high-voltage pulse generator based on pulse transformer with closed magnetic core.

    Science.gov (United States)

    Zhang, Yu; Liu, Jinliang; Cheng, Xinbing; Bai, Guoqiang; Zhang, Hongbo; Feng, Jiahuai; Liang, Bo

    2010-03-01

    A compact high-voltage nanosecond pulse generator, based on a pulse transformer with a closed magnetic core, is presented in this paper. The pulse generator consists of a miniaturized pulse transformer, a curled parallel strip pulse forming line (PFL), a spark gap, and a matched load. The innovative design is characterized by the compact structure of the transformer and the curled strip PFL. A new structure of transformer windings was designed to keep good insulation and decrease distributed capacitance between turns of windings. A three-copper-strip structure was adopted to avoid asymmetric coupling of the curled strip PFL. When the 31 microF primary capacitor is charged to 2 kV, the pulse transformer can charge the PFL to 165 kV, and the 3.5 ohm matched load can deliver a high-voltage pulse with a duration of 9 ns, amplitude of 84 kV, and rise time of 5.1 ns. When the load is changed to 50 ohms, the output peak voltage of the generator can be 165 kV, the full width at half maximum is 68 ns, and the rise time is 6.5 ns.

  4. Analytical Assessment of Voltage Support via Reactive Power from new Electric Vehicles Supply Equipment in Radial Distribution Grids with Voltage-Dependent Loads

    DEFF Research Database (Denmark)

    Zecchino, Antonio; Marinelli, Mattia

    2018-01-01

    Grid operators have to cope with secure electric vehicles integration in the power system, which may lead to violations of the allowed voltage band. This work intends to provide an analytical assessment and guidelines for distribution system operators when evaluating new electric vehicle supply...

  5. Architecture, Voltage, and Components for a Turboelectric Distributed Propulsion Electric Grid (AVC-TeDP)

    Science.gov (United States)

    Gemin, Paul; Kupiszewski, Tom; Radun, Arthur; Pan, Yan; Lai, Rixin; Zhang, Di; Wang, Ruxi; Wu, Xinhui; Jiang, Yan; Galioto, Steve; hide

    2015-01-01

    The purpose of this effort was to advance the selection, characterization, and modeling of a propulsion electric grid for a Turboelectric Distributed Propulsion (TeDP) system for transport aircraft. The TeDP aircraft would constitute a miniature electric grid with 50 MW or more of total power, two or more generators, redundant transmission lines, and multiple electric motors driving propulsion fans. The study proposed power system architectures, investigated electromechanical and solid state circuit breakers, estimated the impact of the system voltage on system mass, and recommended DC bus voltage range. The study assumed an all cryogenic power system. Detailed assumptions within the study include hybrid circuit breakers, a two cryogen system, and supercritical cyrogens. A dynamic model was developed to investigate control and parameter selection.

  6. Distribution and function of voltage-gated sodium channels in the nervous system.

    Science.gov (United States)

    Wang, Jun; Ou, Shao-Wu; Wang, Yun-Jie

    2017-09-18

    Voltage-gated sodium channels (VGSCs) are the basic ion channels for neuronal excitability, which are crucial for the resting potential and the generation and propagation of action potentials in neurons. To date, at least nine distinct sodium channel isoforms have been detected in the nervous system. Recent studies have identified that voltage-gated sodium channels not only play an essential role in the normal electrophysiological activities of neurons but also have a close relationship with neurological diseases. In this study, the latest research findings regarding the structure, type, distribution, and function of VGSCs in the nervous system and their relationship to neurological diseases, such as epilepsy, neuropathic pain, brain tumors, neural trauma, and multiple sclerosis, are reviewed in detail.

  7. An Underappreciated Radiation Hazard from High Voltage Electrodes in Vacuum.

    Science.gov (United States)

    West, Adam D; Lasner, Zack; DeMille, David; West, Elizabeth P; Panda, Cristian D; Doyle, John M; Gabrielse, Gerald; Kryskow, Adam; Mitchell, Corinne

    2017-01-01

    The use of high voltage (HV) electrodes in vacuum is commonplace in physics laboratories. In such systems, it has long been known that electron emission from an HV cathode can lead to bremsstrahlung x rays; indeed, this is the basic principle behind the operation of standard x-ray sources. However, in laboratory setups where x-ray production is not the goal and no electron source is deliberately introduced, field-emitted electrons accelerated by HV can produce x rays as an unintended hazardous byproduct. Both the level of hazard and the safe operating regimes for HV vacuum electrode systems are not widely appreciated, at least in university laboratories. A reinforced awareness of the radiation hazards associated with vacuum HV setups would be beneficial. The authors present a case study of a HV vacuum electrode device operated in a university atomic physics laboratory. They describe the characterization of the observed x-ray radiation, its relation to the observed leakage current in the device, the steps taken to contain and mitigate the radiation hazard, and suggested safety guidelines.

  8. An Underappreciated Radiation Hazard from High Voltage Electrodes in Vacuum

    CERN Document Server

    West, Adam; DeMille, David; West, Elizabeth; Panda, Cristian; Doyle, John; Gabrielse, Gerald; Kryskow, Adam; Mitchell, Corinne

    2016-01-01

    The use of high voltage (HV) electrodes in vacuum is commonplace in physics laboratories. In such systems, it has long been known that electron emission from an HV cathode can lead to bremsstrahlung X-rays; indeed, this is the basic principle behind the operation of standard X-ray sources. However, in laboratory setups where X-ray production is not the goal and no electron source is deliberately introduced, field-emitted electrons accelerated by HV can produce X-rays as an unintended hazardous byproduct. Both the level of hazard and the safe operating regimes for HV vacuum electrode systems are not widely appreciated, at least in university laboratories. A reinforced awareness of the radiation hazards associated with vacuum HV setups would be beneficial. We present a case study of a HV vacuum electrode device operated in a university atomic physics laboratory. We describe the characterisation of the observed X-ray radiation, its relation to the observed leakage current in the device, the steps taken to contai...

  9. Performance of a Remote High Voltage Power Supply for the Phase II Upgrade of the ATLAS Tile Calorimeter

    CERN Document Server

    Vazeille, Francois; The ATLAS collaboration

    2015-01-01

    The experience gained in the working of the present High Voltage system of the Tile calorimeter of the ATLAS detector and the new HL-LHC constraints, in particular the increase of the radiation, lead to the proposal of moving the embedded regulation system to be a remote system in the counting room, by adding easily new functionalities. This system is using the same regulation scheme as the current one and distributes the individual High Voltage settings with multi-conductor cables. The tests show that it reaches the same performance in terms of regulation stability and noise, with a permanent access to the electronics.

  10. Charge and fluence lifetime measurements of a dc high voltage GaAs photogun at high average current

    Directory of Open Access Journals (Sweden)

    J. Grames

    2011-04-01

    Full Text Available GaAs-based dc high voltage photoguns used at accelerators with extensive user programs must exhibit long photocathode operating lifetime. Achieving this goal represents a significant challenge for proposed high average current facilities that must operate at tens of milliamperes or more. This paper describes techniques to maintain good vacuum while delivering beam, and techniques that minimize the ill effects of ion bombardment, the dominant mechanism that reduces photocathode yield of a GaAs-based dc high voltage photogun. Experimental results presented here demonstrate enhanced lifetime at high beam currents by: (a operating with the drive laser beam positioned away from the electrostatic center of the photocathode, (b limiting the photocathode active area to eliminate photoemission from regions of the photocathode that do not support efficient beam delivery, (c using a large drive laser beam to distribute ion damage over a larger area, and (d by applying a relatively low bias voltage to the anode to repel ions created within the downstream beam line. A combination of these techniques provided the best total charge extracted lifetimes in excess of 1000 C at dc beam currents up to 9.5 mA, using green light illumination of bulk GaAs inside a 100 kV photogun.

  11. Charge and fluence lifetime measurements of a dc high voltage GaAs photogun at high average current

    Energy Technology Data Exchange (ETDEWEB)

    J. Grames, R. Suleiman, P.A. Adderley, J. Clark, J. Hansknecht, D. Machie, M. Poelker, M.L. Stutzman

    2011-04-01

    GaAs-based dc high voltage photoguns used at accelerators with extensive user programs must exhibit long photocathode operating lifetime. Achieving this goal represents a significant challenge for proposed high average current facilities that must operate at tens of milliamperes or more. This paper describes techniques to maintain good vacuum while delivering beam, and techniques that minimize the ill effects of ion bombardment, the dominant mechanism that reduces photocathode yield of a GaAs-based dc high voltage photogun. Experimental results presented here demonstrate enhanced lifetime at high beam currents by: (a) operating with the drive laser beam positioned away from the electrostatic center of the photocathode, (b) limiting the photocathode active area to eliminate photoemission from regions of the photocathode that do not support efficient beam delivery, (c) using a large drive laser beam to distribute ion damage over a larger area, and (d) by applying a relatively low bias voltage to the anode to repel ions created within the downstream beam line. A combination of these techniques provided the best total charge extracted lifetimes in excess of 1000 C at dc beam currents up to 9.5 mA, using green light illumination of bulk GaAs inside a 100 kV photogun.

  12. Increase the threshold voltage of high voltage GaN transistors by low temperature atomic hydrogen treatment

    Energy Technology Data Exchange (ETDEWEB)

    Erofeev, E. V., E-mail: erofeev@micran.ru [Tomsk State University of Control Systems and Radioelectronics, Research Institute of Electrical-Communication Systems (Russian Federation); Fedin, I. V.; Kutkov, I. V. [Research and Production Company “Micran” (Russian Federation); Yuryev, Yu. N. [National Research Tomsk Polytechnic University, Institute of Physics and Technology (Russian Federation)

    2017-02-15

    High-electron-mobility transistors (HEMTs) based on AlGaN/GaN epitaxial heterostructures are a promising element base for the fabrication of high voltage electronic devices of the next generation. This is caused by both the high mobility of charge carriers in the transistor channel and the high electric strength of the material, which makes it possible to attain high breakdown voltages. For use in high-power switches, normally off-mode GaN transistors operating under enhancement conditions are required. To fabricate normally off GaN transistors, one most frequently uses a subgate region based on magnesium-doped p-GaN. However, optimization of the p-GaN epitaxial-layer thickness and the doping level makes it possible to attain a threshold voltage of GaN transistors close to V{sub th} = +2 V. In this study, it is shown that the use of low temperature treatment in an atomic hydrogen flow for the p-GaN-based subgate region before the deposition of gate-metallization layers makes it possible to increase the transistor threshold voltage to V{sub th} = +3.5 V. The effects under observation can be caused by the formation of a dipole layer on the p-GaN surface induced by the effect of atomic hydrogen. The heat treatment of hydrogen-treated GaN transistors in a nitrogen environment at a temperature of T = 250°C for 12 h reveals no degradation of the transistor’s electrical parameters, which can be caused by the formation of a thermally stable dipole layer at the metal/p-GaN interface as a result of hydrogenation.

  13. Phase-wise enhanced voltage support from electric vehicles in a Danish low-voltage distribution grid

    DEFF Research Database (Denmark)

    Knezovic, Katarina; Marinelli, Mattia

    2016-01-01

    while the energy losses are not notably increased. Further on, since the control is voltage dependent, provided reactive power is unequal among the phases leading to greater support on heavily loaded phases and decreased unbalances caused by residential consumption. Hence, implementation of such a phase-wise...

  14. High-Mixed-Voltage Analog and RF Circuit Techniques for Nanoscale CMOS

    CERN Document Server

    Mak, Pui-In

    2012-01-01

    This book presents high-/mixed-voltage analog and radio frequency (RF) circuit techniques for developing low-cost multistandard wireless receivers in nm-length CMOS processes.  Key benefits of high-/mixed-voltage RF and analog CMOS circuits are explained, state-of-the-art examples are studied, and circuit solutions before and after voltage-conscious design are compared. Three real design examples are included, which demonstrate the feasibility of high-/mixed-voltage circuit techniques.    Provides a valuable summary and real case studies of the state-of-the-art in high-/mixed-voltage circuits and systems; Includes novel high-/mixed-voltage analog and RF circuit techniques – from concept to practice; Describes the first high-voltage-enabled mobile-TVRF front-end in 90nm CMOS and the first mixed-voltage full-band mobile-TV Receiver in 65nm CMOS; Demonstrates the feasibility of high-/mixed-voltage circuit techniques with real design examples.  

  15. Locational Pricing to Mitigate Voltage Problems Caused by High PV Penetration

    OpenAIRE

    Sam Weckx; Reinhilde D'hulst; Johan Driesen

    2015-01-01

    In this paper, a locational marginal pricing algorithm is proposed to control the voltage in unbalanced distribution grids. The increasing amount of photovoltaic (PV) generation installed in the grid may cause the voltage to rise to unacceptable levels during periods of low consumption. With locational prices, the distribution system operator can steer the reactive power consumption and active power curtailment of PV panels to guarantee a safe network operation. Flexible loads also respond to...

  16. Distributed Secondary Voltage and Frequency Control for Islanded Microgrids with Uncertain Communication Links

    DEFF Research Database (Denmark)

    Lu, Xiaoqing; Yu, Xinghuo; Lai, Jingang

    2017-01-01

    This paper presents a robust distributed secondary control (DSC) scheme for inverter-based microgrids (MGs) in a distribution sparse network with uncertain communication links. By using the iterative learning mechanics, two discrete-time DSC controllers are designed, which enable all distributed...... intermittently in a low-bandwidth communication manner. This way, the communication costs are greatly reduced, and some sufficient conditions on the system stability and robustness to the uncertainties are also derived by using the tools of Lyapunov stability theory, algebraic graph theory, and matrix inequality...... theory. The proposed controllers are implemented on local DERs, and thus no central controller is required. Moreover, the desired control objective can also be guaranteed even if all DERs are subject to internal uncertainties and external noises including initial voltage and/or frequency resetting errors...

  17. Electric Power High-Voltage Transmission Lines: Design Options, Cost, and Electric and Magnetic Field Levels

    Energy Technology Data Exchange (ETDEWEB)

    Stoffel, J. B. [Argonne National Lab. (ANL), Argonne, IL (United States). Environmental Assessment Division. Electronics and Computing Technologies Division; Pentecost, E. D. [Argonne National Lab. (ANL), Argonne, IL (United States). Environmental Assessment Division; Roman, R. D. [Argonne National Lab. (ANL), Argonne, IL (United States). Environmental Assessment Division; Traczyk, P. A. [Argonne National Lab. (ANL), Argonne, IL (United States). Environmental Assessment Division

    1994-11-01

    The aim of this report is to provide background information about (1) the electric and magnetic fields (EMFs) of high-voltage transmission lines at typical voltages and line configurations and (2) typical transmission line costs to assist preparers and reviewers of the section on alternatives in environmental documents. This report will give the reviewing individual a better appreciation of the factors affecting EMF strengths near high-voltage transmission lines and the approaches that might be used to reduce EMF impacts on humans and other biological species in the vicinity of high-voltage overhead or underground alternating-current (ac) or direct-current (dc) transmission lines.

  18. Validation of a Cochlear Implant Patient Specific Model of the Voltage Distribution in a Clinical Setting

    Directory of Open Access Journals (Sweden)

    Waldo Nogueira

    2016-11-01

    Full Text Available Cochlear Implants (CIs are medical implantable devices that can restore the sense of hearing in people with profound hearing loss. Clinical trials assessing speech intelligibility in CI users have found large inter-subject variability. One possibility to explain the variability is the individual differences in the interface created between electrodes of the CI and the auditory nerve. In order to understand the variability, models of the voltage distribution of the electrically stimulated cochlea may be useful. With this purpose in mind, we developed a parametric model that can be adapted to each CI user based on landmarks from individual cone beam computed tomography (CBCT scans of the cochlea before and after implantation. The conductivity values of each cochlea compartment as well as the weighting factors of different grounding modes have been also parameterized. Simulations were performed modeling the cochlea and electrode positions of 12 CI users. Three models were compared with different levels of detail: A homogeneous model (HM, a non-patient specific model (NPSM and a patient specific model (PSM. The model simulations were compared with voltage distribution measurements obtained from the backward telemetry of the 12 CI users. Results show that the PSM produces the lowest error when predicting individual voltage distributions. Given a patient specific geometry and electrode positions we show an example on how to optimize the parameters of the model and how to couple it to an auditory nerve model. The model here presented may help to understand speech performance variability and support the development of new sound coding strategies for CIs.

  19. CLASSIFICATION OF POWER QUALITY CONSIDERING VOLTAGE SAGS IN DISTRIBUTION SYSTEMS USING KDD PROCESS

    Directory of Open Access Journals (Sweden)

    Anderson Roges Teixeira Góes

    2015-08-01

    Full Text Available In this paper, we propose a methodology to classify Power Quality (PQ in distribution systems based on voltage sags. The methodology uses the KDD process (Knowledge Discovery in Databases in order to establish a quality level to be printed in labels. The methodology was applied to feeders on a substation located in Curitiba, Paraná, Brazil, considering attributes such as sag length (remnant voltage, duration and frequency (number of occurrences on a given period of time. On the Data Mining Stage (the main stage on KDD Process, three different techniques were used, in a comparative way, for pattern recognition, in order to achieve the quality classification for the feeders: Artificial Neural Networks (ANN; Support Vector Machines (SVM and Genetic Algorithms (GA. By printing a label with quality level information, utilities companies (power concessionaires can get better organized for mitigation procedures by establishing clear targets. Moreover, the same way costumers already receive information regarding PQ based on interruptions, they will also be able to receive information based on voltage sags.

  20. Novel methods for earth fault management in medium voltage distribution networks

    Energy Technology Data Exchange (ETDEWEB)

    Nikander, A.; Jaerventausta, P. [Tampere Univ. of Technology (Finland)

    1998-08-01

    Customers have become less and less tolerable against even short interruptions of supply. Rapid autoreclosures are especially harmful for those commercial and private customers who have equipment which will be disturbed by these under half second interruptions. Mainly due to increasing use of distribution automation (eg. remote controlled switching devices, fault detectors, computational fault location) the average interruption period per customer has been reduced. Simultaneously the amount of equipment sensitive to short voltage break or dip has increased. Therefore reducing the number of the interruptions has become a more essential target

  1. High precision, low disturbance calibration of the High Voltage system of the CMS Barrel Electromagnetic Calorimeter

    CERN Document Server

    Fasanella, Giuseppe

    2016-01-01

    The CMS Electromagnetic Calorimeter utilizes scintillating lead tungstate crystals, with avalanche photodiodes (APD) as photo-detectors in the barrel part. 1224 HV channels bias groups of 50 APD pairs, each at a voltage of about 380 V. The APD gain dependence on the voltage is 3pct/V. A stability of better than 60 mV is needed to have negligible impact on the calorimeter energy resolution. Until 2015 manual calibrations were performed yearly. A new calibration system was deployed recently, which satisfies the requirement of low disturbance and high precision. The system is discussed in detail and first operational experience is presented.

  2. High Bandwidth Zero Voltage Injection Method for Sensorless Control of PMSM

    DEFF Research Database (Denmark)

    Ge, Xie; Lu, Kaiyuan; Kumar, Dwivedi Sanjeet

    2014-01-01

    High frequency signal injection is widely used in PMSM sensorless control system for low speed operations. The conventional voltage injection method often needs filters to obtain particular harmonic component in order to estimate the rotor position; or it requires several voltage pulses to be inj......High frequency signal injection is widely used in PMSM sensorless control system for low speed operations. The conventional voltage injection method often needs filters to obtain particular harmonic component in order to estimate the rotor position; or it requires several voltage pulses...

  3. Integrated Reconfigurable High-Voltage Transmitting Circuit for CMUTs

    DEFF Research Database (Denmark)

    Llimos Muntal, Pere; Larsen, Dennis Øland; Jørgensen, Ivan Harald Holger

    2014-01-01

    -out and measurements are performed on the integrated circuit. The transmitting circuit is reconfigurable externally making it able to drive a wide variety of CMUTs. The transmitting circuit can generate several pulse shapes, pulse voltages up to 100 V, maximum pulse range of 50 V and frequencies up to 5 MHz. The area...

  4. Estimation of Backward Impedance on Low-Voltage Distribution System using Measured Resonant Current

    Science.gov (United States)

    Miki, Toru; Konishi, Kazuki; Morimoto, Koji; Nagaoka, Naoto; Ametani, Akihiro

    Two estimation methods for a backward impedance of a power distribution system are proposed in this paper. A frequency response of a transient current flowing into a capacitor, which connected to a distribution line, has information of the backward impedance. The impedance is obtained from an attenuation constant and a resonance frequency determined by the capacitance and the impedance of power distribution system. These parameters are stably obtained from a frequency response of the transient current using a least square method. The accuracy of the method heavily depends on the origin on the time-axis for Fourier transform. Additional time-origin estimation is required for an accurate estimation of the backward impedance. The second method estimates the backward impedance using two transient current waveforms obtained by connecting alternately different capacitors to a distribution line. The backward impedance can be represented as a function of the frequency responses of these current. This method is suitable for an automatic measurement of the backward impedance because the method is independent from the time-origin. The proposed methods are applicable to an estimation of a harmonic current of the distribution system. In this paper, a harmonic current flowing through a distribution wire is estimated from the estimated backward impedance and the measured results of harmonic voltages obtained by an instrument developed by the authors.

  5. A novel series connected batteries state of high voltage safety monitor system for electric vehicle application.

    Science.gov (United States)

    Jiaxi, Qiang; Lin, Yang; Jianhui, He; Qisheng, Zhou

    2013-01-01

    Batteries, as the main or assistant power source of EV (Electric Vehicle), are usually connected in series with high voltage to improve the drivability and energy efficiency. Today, more and more batteries are connected in series with high voltage, if there is any fault in high voltage system (HVS), the consequence is serious and dangerous. Therefore, it is necessary to monitor the electric parameters of HVS to ensure the high voltage safety and protect personal safety. In this study, a high voltage safety monitor system is developed to solve this critical issue. Four key electric parameters including precharge, contact resistance, insulation resistance, and remaining capacity are monitored and analyzed based on the equivalent models presented in this study. The high voltage safety controller which integrates the equivalent models and control strategy is developed. By the help of hardware-in-loop system, the equivalent models integrated in the high voltage safety controller are validated, and the online electric parameters monitor strategy is analyzed and discussed. The test results indicate that the high voltage safety monitor system designed in this paper is suitable for EV application.

  6. 30 CFR 77.704 - Work on high-voltage lines; deenergizing and grounding.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Work on high-voltage lines; deenergizing and grounding. 77.704 Section 77.704 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... OF UNDERGROUND COAL MINES Grounding § 77.704 Work on high-voltage lines; deenergizing and grounding...

  7. 30 CFR 75.705 - Work on high-voltage lines; deenergizing and grounding.

    Science.gov (United States)

    2010-07-01

    ... grounding. 75.705 Section 75.705 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Grounding § 75.705 Work on high-voltage lines; deenergizing and grounding. High-voltage lines, both on the surface and...

  8. 30 CFR 77.802 - Protection of high-voltage circuits; neutral grounding resistors; disconnecting devices.

    Science.gov (United States)

    2010-07-01

    ... grounding resistors; disconnecting devices. 77.802 Section 77.802 Mineral Resources MINE SAFETY AND HEALTH... of high-voltage circuits; neutral grounding resistors; disconnecting devices. High-voltage circuits... grounded through a suitable resistor at the source transformers, and a grounding circuit, originating at...

  9. 76 FR 26183 - Safety Zone; Repair of High Voltage Transmission Lines to Logan International Airport, Saugus...

    Science.gov (United States)

    2011-05-06

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Repair of High Voltage Transmission Lines... transmission lines to Logan Airport. This safety zone is required to provide for the safety of life on navigable waters during the repair of high voltage transmission lines. Entering into, transiting through...

  10. 75 FR 20918 - High-Voltage Continuous Mining Machine Standard for Underground Coal Mines

    Science.gov (United States)

    2010-04-22

    ... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF LABOR Mine Safety and Health Administration 30 CFR Parts 18 and 75 RIN 1219-AB34 High-Voltage Continuous Mining... the table titled Table 10--HIGH VOLTAGE TRAILING CABLE AMPACITIES AND OUTSIDE DIAMETERS, the first...

  11. A Novel Series Connected Batteries State of High Voltage Safety Monitor System for Electric Vehicle Application

    Directory of Open Access Journals (Sweden)

    Qiang Jiaxi

    2013-01-01

    Full Text Available Batteries, as the main or assistant power source of EV (Electric Vehicle, are usually connected in series with high voltage to improve the drivability and energy efficiency. Today, more and more batteries are connected in series with high voltage, if there is any fault in high voltage system (HVS, the consequence is serious and dangerous. Therefore, it is necessary to monitor the electric parameters of HVS to ensure the high voltage safety and protect personal safety. In this study, a high voltage safety monitor system is developed to solve this critical issue. Four key electric parameters including precharge, contact resistance, insulation resistance, and remaining capacity are monitored and analyzed based on the equivalent models presented in this study. The high voltage safety controller which integrates the equivalent models and control strategy is developed. By the help of hardware-in-loop system, the equivalent models integrated in the high voltage safety controller are validated, and the online electric parameters monitor strategy is analyzed and discussed. The test results indicate that the high voltage safety monitor system designed in this paper is suitable for EV application.

  12. High voltage bus and auxiliary heater control system for an electric or hybrid vehicle

    Science.gov (United States)

    Murty, Balarama Vempaty

    2000-01-01

    A control system for an electric or hybrid electric vehicle includes a vehicle system controller and a control circuit having an electric immersion heater. The heater is electrically connected to the vehicle's high voltage bus and is thermally coupled to a coolant loop containing a heater core for the vehicle's climate control system. The system controller responds to cabin heat requests from the climate control system by generating a pulse width modulated signal that is used by the control circuit to operate the heater at a duty cycle appropriate for the amount of cabin heating requested. The control system also uses the heater to dissipate excess energy produced by an auxiliary power unit and to provide electric braking when regenerative braking is not desirable and manual braking is not necessary. The control system further utilizes the heater to provide a safe discharge of a bank of energy storage capacitors following disconnection of the battery or one of the high voltage connectors used to transmit high voltage operating power to the various vehicle systems. The control circuit includes a high voltage clamping circuit that monitors the voltage on the bus and operates the heater to clamp down the bus voltage when it exceeds a pre-selected maximum voltage. The control system can also be used to phase in operation of the heater when the bus voltage exceeds a lower threshold voltage and can be used to phase out the auxiliary power unit charging and regenerative braking when the battery becomes fully charged.

  13. Particle flows to shape and voltage surface discontinuities in the electron sheath surrounding a high voltage solar array in LEO

    Science.gov (United States)

    Metz, Roger N.

    1991-01-01

    This paper discusses the numerical modeling of electron flows from the sheath surrounding high positively biased objects in LEO (Low Earth Orbit) to regions of voltage or shape discontinuity on the biased surfaces. The sheath equations are derived from the Two-fluid, Warm Plasma Model. An equipotential corner and a plane containing strips of alternating voltage bias are treated in two dimensions. A self-consistent field solution of the sheath equations is outlined and is pursued through one cycle. The electron density field is determined by numerical solution of Poisson's equation for the electrostatic potential in the sheath using the NASCAP-LEO relation between electrostatic potential and charge density. Electron flows are calculated numerically from the electron continuity equation. Magnetic field effects are not treated.

  14. A Study on Real-Time Pricing Method of Reactive Power in Voltage Profile Control Method of Future Distribution Network

    Science.gov (United States)

    Koide, Akira; Tsuji, Takao; Oyama, Tsutomu; Hashiguchi, Takuhei; Goda, Tadahiro; Shinji, Takao; Tsujita, Shinsuke

    It is of prime importance to solve the voltage maintenance problem caused by the introduction of a large number of distributed generators. The authors have proposed “voltage profile control method” using reactive power control of distributed generators and developed new systems which can give economical incentives to DG owners who cooperate the voltage profile management in the previous works. However, it is difficult to apply the proposed economical systems to real-time operation because they are based on the optimization technology and the specific amount of incentive is informed after the control action has finished. Therefore, in this paper, we develop a new method that can determine the amount of incentives in real-time and encourage the costumers to cooperate voltage profile control method. The proposed method is tested in one feeder distribution network and its effectiveness is shown.

  15. Effect of recovery time of fault current limiter on over current from distributed generator in micro grid after voltage sag

    Directory of Open Access Journals (Sweden)

    Daisuke Iioka

    2016-01-01

    Full Text Available This paper describes an effect of recovery time of fault current limiter on over current from a micro grid system which is interconnected to a power distribution system. We have assumed that the semi-conductor type fault current limiter is installed between the micro grid system with the synchronous generator and the power distribution system, measured the over current after a voltage sag occurrence in the power distribution system and a recovery of fault current limiter by experiments in our laboratory. Finally, it was found that the introduction of recovery time for fault current limiter after voltage sag is useful for suppressing the over current from the distributed generator.

  16. Statistical Feature Extraction for Fault Locations in Nonintrusive Fault Detection of Low Voltage Distribution Systems

    Directory of Open Access Journals (Sweden)

    Hsueh-Hsien Chang

    2017-04-01

    Full Text Available This paper proposes statistical feature extraction methods combined with artificial intelligence (AI approaches for fault locations in non-intrusive single-line-to-ground fault (SLGF detection of low voltage distribution systems. The input features of the AI algorithms are extracted using statistical moment transformation for reducing the dimensions of the power signature inputs measured by using non-intrusive fault monitoring (NIFM techniques. The data required to develop the network are generated by simulating SLGF using the Electromagnetic Transient Program (EMTP in a test system. To enhance the identification accuracy, these features after normalization are given to AI algorithms for presenting and evaluating in this paper. Different AI techniques are then utilized to compare which identification algorithms are suitable to diagnose the SLGF for various power signatures in a NIFM system. The simulation results show that the proposed method is effective and can identify the fault locations by using non-intrusive monitoring techniques for low voltage distribution systems.

  17. Measurements of power loss distribution in a typical stator core under PWM voltage excitation

    Science.gov (United States)

    Tutkun, N.; Moses, A. J.

    2003-06-01

    The pulse width modulated (PWM) inverter is widely used to feed small induction motors for variable speed and torque control. When a laminated stator core is energised in this way additional iron losses occur due to localised distorted flux. Flux density and power loss distribution under PWM and sinusoidal voltage excitations were measured in a typical induction motor stator core lamination at 1.3 T, 50 Hz by using a computer-aided magnetising system to set up flux distribution as would occur in a practical three-phase stator core. The iron loss increased 15-20% under PWM excitation. The loss increase under PWM excitation in the stator core laminations was 3% lower than in Epstein strips of the same electrical steel under the same conditions showing an effect of the magnetic circuit geometry.

  18. Extension of the Accurate Voltage-Sag Fault Location Method in Electrical Power Distribution Systems

    Directory of Open Access Journals (Sweden)

    Youssef Menchafou

    2016-03-01

    Full Text Available Accurate Fault location in an Electric Power Distribution System (EPDS is important in maintaining system reliability. Several methods have been proposed in the past. However, the performances of these methods either show to be inefficient or are a function of the fault type (Fault Classification, because they require the use of an appropriate algorithm for each fault type. In contrast to traditional approaches, an accurate impedance-based Fault Location (FL method is presented in this paper. It is based on the voltage-sag calculation between two measurement points chosen carefully from the available strategic measurement points of the line, network topology and current measurements at substation. The effectiveness and the accuracy of the proposed technique are demonstrated for different fault types using a radial power flow system. The test results are achieved from the numerical simulation using the data of a distribution line recognized in the literature.

  19. Voltage Unbalance and Harmonic Compensation in Microgrids by Cooperation of Distributed Generators and Active Power Filters

    DEFF Research Database (Denmark)

    Hashempour, Mohammad M.; Savaghebi, Mehdi; Quintero, Juan Carlos Vasquez

    2016-01-01

    , selective virtual impedance and voltage/current regulators. Based on the secondary control, at first voltage harmonic compensation and voltage unbalance compensation of point of common coupling (PCC), that might includes sensitive loads, is carried out by DGs. Voltage compensation of PCC by DGs may cause...

  20. High-Capacity Cathode Material with High Voltage for Li-Ion Batteries.

    Science.gov (United States)

    Shi, Ji-Lei; Xiao, Dong-Dong; Ge, Mingyuan; Yu, Xiqian; Chu, Yong; Huang, Xiaojing; Zhang, Xu-Dong; Yin, Ya-Xia; Yang, Xiao-Qing; Guo, Yu-Guo; Gu, Lin; Wan, Li-Jun

    2018-01-15

    Electrochemical energy storage devices with a high energy density are an important technology in modern society, especially for electric vehicles. The most effective approach to improve the energy density of batteries is to search for high-capacity electrode materials. According to the concept of energy quality, a high-voltage battery delivers a highly useful energy, thus providing a new insight to improve energy density. Based on this concept, a novel and successful strategy to increase the energy density and energy quality by increasing the discharge voltage of cathode materials and preserving high capacity is proposed. The proposal is realized in high-capacity Li-rich cathode materials. The average discharge voltage is increased from 3.5 to 3.8 V by increasing the nickel content and applying a simple after-treatment, and the specific energy is improved from 912 to 1033 Wh kg-1 . The current work provides an insightful universal principle for developing, designing, and screening electrode materials for high energy density and energy quality. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Tesla’s high voltage and high frequency generators with oscillatory circuits

    OpenAIRE

    Cvetić Jovan M.

    2016-01-01

    The principles that represent the basics of the work of the high voltage and high frequency generator with oscillating circuits will be discussed. Until 1891, Tesla made and used mechanical generators with a large number of extruded poles for the frequencies up to about 20 kHz. The first electric generators based on a new principle of a weakly coupled oscillatory circuits he used for the wireless signal transmission, for the study of the discharges in vacuu...

  2. A high-voltage test for the ATLAS RPC qualification

    CERN Document Server

    Aielli, G; Cardarelli, R; Di Ciaccio, A; Di Simone, A; Liberti, B; Santonico, R

    2004-01-01

    The RPC production sequence for the ATLAS experiment includes a specific test of current absorption at the operating point, which concerns the RPC "gas volumes", namely the bare detectors not yet assembled with the read-out panels and the mechanical support structures. The test, which is carried out at the production site, consists of two phases. The gas volumes are initially conditioned with pure argon, keeping the voltage constant just above the breakdown value of about 2 kV. The final test, performed after the volumes have undergone inner surface varnishing with linseed oil, is based on the measurement of the current-voltage characteristics with the binary operating gas, C//2H//2F//4/i-C//4H//1//0 = 95/5. The results presented here concern 45% of the total foreseen production.

  3. Fast Coordinated Control of DFIG Wind Turbine Generators for Low and High Voltage Ride-Through

    DEFF Research Database (Denmark)

    Wang, Yun; Wu, Qiuwei; Xu, Honghua

    2014-01-01

    (HVRT) capability of the DFIG WTGs. The characteristics of DFIG WTGs under voltage sags and swells were studied focusing on the DFIG WTG stator flux and rotor voltages during the transient periods of grid voltage changes. The protection schemes of the rotor crowbar circuit and the dc chopper circuit......This paper presents a fast coordinated control scheme of the rotor side converter (RSC), the DC chopper and the grid side converter (GSC) of doubly fed induction generator (DFIG) wind turbine generators (WTGs) which is to improve the low voltage ride through (LVRT) and high voltage ride through...... were proposed considering the characteristics of the DFIG WTGs during voltage changes. The fast coordinated control of RSC and GSC were developed based on the characteristic analysis in order to realize efficient LVRT and HVRT of the DFIG WTGs. The proposed fast coordinated control schemes were...

  4. Fast Coordinated Control of DFIG Wind Turbine Generators for Low and High Voltage Ride-Through

    Directory of Open Access Journals (Sweden)

    Yun Wang

    2014-06-01

    Full Text Available This paper presents a fast coordinated control scheme of the rotor side converter (RSC, the Direct Current (DC chopper and the grid side converter (GSC of doubly fed induction generator (DFIG wind turbine generators (WTGs to improve the low voltage ride through (LVRT and high voltage ride through (HVRT capability of the DFIG WTGs. The characteristics of DFIG WTGs under voltage sags and swells were studied focusing on the DFIG WTG stator flux and rotor voltages during the transient periods of grid voltage changes. The protection schemes of the rotor crowbar circuit and the DC chopper circuit were proposed considering the characteristics of the DFIG WTGs during voltage changes. The fast coordinated control of RSC and GSC were developed based on the characteristic analysis in order to realize efficient LVRT and HVRT of the DFIG WTGs. The proposed fast coordinated control schemes were verified by time domain simulations using Matlab-Simulink.

  5. A Novel Method for In-Situ Monitoring of Local Voltage, Temperature and Humidity Distributions in Fuel Cells Using Flexible Multi-Functional Micro Sensors

    Directory of Open Access Journals (Sweden)

    Chih-Ping Chang

    2011-01-01

    Full Text Available In this investigation, micro voltage, temperature and humidity sensors were fabricated and integrated for the first time on a stainless steel foil using micro-electro-mechanical systems (MEMS. These flexible multi-functional micro sensors have the advantages of high temperature resistance, flexibility, smallness, high sensitivity and precision of location. They were embedded in a proton exchange membrane fuel cell (PEMFC and used to simultaneously measure variations in the inner voltage, temperature and humidity. The accuracy and reproducibility of the calibrated results obtained using the proposed micro sensors is excellent. The experimental results indicate that, at high current density and 100%RH or 75%RH, the relative humidity midstream and downstream saturates due to severe flooding. The performance of the PEM fuel cell can be stabilized using home-made flexible multi-functional micro sensors by the in-situ monitoring of local voltage, temperature and humidity distributions within it.

  6. A Novel Method for In-Situ Monitoring of Local Voltage, Temperature and Humidity Distributions in Fuel Cells Using Flexible Multi-Functional Micro Sensors

    Science.gov (United States)

    Lee, Chi-Yuan; Fan, Wei-Yuan; Chang, Chih-Ping

    2011-01-01

    In this investigation, micro voltage, temperature and humidity sensors were fabricated and integrated for the first time on a stainless steel foil using micro-electro-mechanical systems (MEMS). These flexible multi-functional micro sensors have the advantages of high temperature resistance, flexibility, smallness, high sensitivity and precision of location. They were embedded in a proton exchange membrane fuel cell (PEMFC) and used to simultaneously measure variations in the inner voltage, temperature and humidity. The accuracy and reproducibility of the calibrated results obtained using the proposed micro sensors is excellent. The experimental results indicate that, at high current density and 100%RH or 75%RH, the relative humidity midstream and downstream saturates due to severe flooding. The performance of the PEM fuel cell can be stabilized using home-made flexible multi-functional micro sensors by the in-situ monitoring of local voltage, temperature and humidity distributions within it. PMID:22319361

  7. Analysis and Design of a DSTATCOM Based on Sliding Mode Control Strategy for Improvement of Voltage Sag in Distribution Systems

    Directory of Open Access Journals (Sweden)

    Ghazanfar Shahgholian

    2016-07-01

    Full Text Available Voltage sag is considered to be the most serious problem of power quality. It is caused by faults in the power system or by the starting of large induction motors. Voltage sag causes about 80% of the power quality problems in power systems. One of the main reasons for voltage sag is short circuit fault, which can be compensated for by a distribution static compensator (DSTATCOM as an efficient and economical flexible AC transmission system (FACTS device. In this paper, compensation of this voltage sag using DSTATCOM is reviewed, in which a sliding mode control (SMC technique is employed. The results of this control system are compared with a P+Resonant control system. It will be shown that this control system is able to compensate the voltage sag over a broader range compared to other common control systems. Simulation results are obtained using PSCAD/EMTDC software and compared to that of a similar method.

  8. Design of a pulsewidth-modulated resonant converter for a high-output-voltage power supply

    Science.gov (United States)

    Turnbull, Fred G.; Tompkins, Russell E.

    1987-12-01

    The design and fabrication of a parallel resonant converter circuit and a high-frequency step-up transformer used to supply an adjustable dc voltage to a load is described. The 500-W system is operated from 115/230 V single-phase 60Hz power, which is rectified and filtered to form a 310-V dc link. A two-transistor half-bridge circuit operating at a fixed frequency above the ciruits resonant frequency converts the dc voltage to an ac voltage at approximately 20 kHx. This high-frequency voltage is transformed with a low-capacitance oil-impregnated ferrite transformer. The output voltage is rectified to form a dc voltage with a maximum value of 90-kV peak. The output voltage is adjustable using pulsewidth modulation of the conduction time of the two transistors in the power circuit. The energy stored in the resonant circuit provides a sinusoidal transformer voltage at fixed frequency over a wide range of control. The system is provided with a closed-loop peak-voltage regulator and an on-off capability from the control electronics. The transformer is designed for a specific value of inductance and capacitance to operate at the desired resonant frequency and characteristic impedance.

  9. Evaluation of high-voltage, high-power, solid-state remote power controllers for amps

    Science.gov (United States)

    Callis, Charles P.

    1987-01-01

    The Electrical Power Branch at Marshall Space Flight Center has a Power System Development Facility where various power circuit breadboards are tested and evaluated. This project relates to the evaluation of a particular remote power controller (RPC) energizing high power loads. The Facility equipment permits the thorough testing and evaluation of high-voltage, high-power solid-state remote power controllers. The purpose is to evaluate a Type E, 30 Ampere, 200 V dc remote power controller. Three phases of the RPC evaluation are presented. The RPC is evaluated within a low-voltage, low-power circuit to check its operational capability. The RPC is then evaluated while performing switch/circuit breaker functions within a 200 V dc, 30 Ampere power circuit. The final effort of the project relates to the recommended procedures for installing these RPC's into the existing Autonomously Managed Power System (AMPS) breadboard/test facility at MSFC.

  10. High Input Voltage Discharge Supply for High Power Hall Thrusters Using Silicon Carbide Devices

    Science.gov (United States)

    Pinero, Luis R.; Scheidegger, Robert J.; Aulsio, Michael V.; Birchenough, Arthur G.

    2014-01-01

    A power processing unit for a 15 kW Hall thruster is under development at NASA Glenn Research Center. The unit produces up to 400 VDC with two parallel 7.5 kW discharge modules that operate from a 300 VDC nominal input voltage. Silicon carbide MOSFETs and diodes were used in this design because they were the best choice to handle the high voltage stress while delivering high efficiency and low specific mass. Efficiencies in excess of 97 percent were demonstrated during integration testing with the NASA-300M 20 kW Hall thruster. Electromagnet, cathode keeper, and heater supplies were also developed and will be integrated with the discharge supply into a vacuum-rated brassboard power processing unit with full flight functionality. This design could be evolved into a flight unit for future missions that requires high power electric propulsion.

  11. DEVELOPMENT OF HIGH-VOLTAGE HIGH-FREQUENCY POWER SUPPLY FOR OZONE GENERATION

    Directory of Open Access Journals (Sweden)

    NACERA HAMMADI

    2016-05-01

    Full Text Available A high-voltage high-frequency power supply for ozone generation is presented in this paper. Ozone generation is intended to be used in air and in water disinfection. A power stage consisting of a single-phase full bridge inverter for regulating the output power, a current push-pull inverter (driver and a control circuit are described and analyzed. This laboratory build power supply using a high voltage ferrite transformer and a PIC microcontroller was employed to energize a dielectric barrier discharge (DBD ozone generator. The inverter working on the basis of control strategy is of simple structure and has a variation range of the working frequency in order to obtain the optimal frequency value. The experimental results concerning electrical characterization and water treatment using a cylindrical DBD ozone generator supplied by this power supply are given in the end.

  12. Loss Distribution and Thermal Behaviour of the Y-source Converter for a Wide Power and Voltage Range

    DEFF Research Database (Denmark)

    Gadalla, Brwene Salah Abdelkarim; Schaltz, Erik; Siwakoti, Yam Prasad

    2017-01-01

    The Y-source converter is one of the recent proposed impedance source converters. It has some advantages as having a high voltage gain between the input and output voltage sides using very small duty cycle ratios. For many applications, the input voltage needs to be boosted to higher output voltage...... and power range is presented. The influence of the heat losses generated in the converter is also considered for different analysis. A simulation model is developed and verified experimentally rated at 300 W....

  13. An Integrated Chip High-Voltage Power Receiver for Wireless Biomedical Implants

    Directory of Open Access Journals (Sweden)

    Vijith Vijayakumaran Nair

    2015-06-01

    Full Text Available In near-field wireless-powered biomedical implants, the receiver voltage largely overrides the compliance of low-voltage power receiver systems. To limit the induced voltage, generally, low-voltage topologies utilize limiter circuits, voltage clippers or shunt regulators, which are power-inefficient methods. In order to overcome the voltage limitation and improve power efficiency, we propose an integrated chip high-voltage power receiver based on the step down approach. The topology accommodates voltages as high as 30 V and comprises a high-voltage semi-active rectifier, a voltage reference generator and a series regulator. Further, a battery management circuit that enables safe and reliable implant battery charging based on analog control is proposed and realized. The power receiver is fabricated in 0.35-μm high-voltage Bipolar-CMOS-DMOStechnology based on the LOCOS0.35-μm CMOS process. Measurement results indicate 83.5% power conversion efficiency for a rectifier at 2.1 mA load current. The low drop-out regulator based on the current buffer compensation and buffer impedance attenuation scheme operates with low quiescent current, reduces the power consumption and provides good stability. The topology also provides good power supply rejection, which is adequate for the design application. Measurement results indicate regulator output of 4 ± 0.03 V for input from 5 to 30 V and 10 ± 0.05 V output for input from 11 to 30 V with load current 0.01–100 mA. The charger circuit manages the charging of the Li-ion battery through all if the typical stages of the Li-ion battery charging profile.

  14. High performance AC–DC control power supply for low voltage ride ...

    Indian Academy of Sciences (India)

    Home; Journals; Sadhana; Volume 41; Issue 2 ... The CPS design presented here maintains a constant 24Vdc output even over a wide (90Vrms to 270Vrms ) ac voltage variation at its input for a High Power Converter (HPC). ... The CPS was tested for wide input voltage range (vin) and the performance validates the design.

  15. High voltage conversion ratio, switched C & L cells, step-down DC-DC converter

    DEFF Research Database (Denmark)

    Pelan, Ovidiu; Muntean, Nicolae; Cornea, Octavian

    2013-01-01

    The paper presents a high voltage conversion ratio DC-DC step-down topology obtained from a classical buck converter associated with an input switched-capacitor cell and an output switched-inductor cell. Analytical descriptions, the voltage and current limits of the main components are synthesize...

  16. Nonlinear Parasitic Capacitance Modelling of High Voltage Power MOSFETs in Partial SOI Process

    DEFF Research Database (Denmark)

    Fan, Lin; Knott, Arnold; Jørgensen, Ivan Harald Holger

    2016-01-01

    : off-state, sub-threshold region, and on-state in the linear region. A high voltage power MOSFET is designed in a partial Silicon on Insulator (SOI) process, with the bulk as a separate terminal. 3D plots and contour plots of the capacitances versus bias voltages for the transistor summarize...

  17. A Complex Permittivity Based Sensor for the Electrical Characterization of High-Voltage Transformer Oils

    Directory of Open Access Journals (Sweden)

    Panayota Vassiliou

    2005-05-01

    Full Text Available This work investigates the use of a specially designed cylindrical metal cell, inorder to obtain complex permittivity and tanδ data of highly insulating High Voltage (HVtransformer oil samples. The data are obtained at a wide range of frequencies and operationtemperatures to demonstrate the polarization phenomena and the thermally stimulatedeffects. Such complex permittivity measurements may be utilized as a criterion for theservice life prediction of oil field electrical equipment (OFEE. Therefore, by one set ofmeasurements on a small oil volume, data may be provided on the impending termination,or continuation of the transformer oil service life. The oil incorporating cell, attached to theappropriate measuring units, could be described as a complex permittivity sensor. In thiswork, the acquired dielectric data from a great number of operating distribution networkpower transformers were correlated to corresponding physicochemical ones to demonstratethe future potential employment of the proposed measuring technique.

  18. A Complex Permittivity Based Sensor for the Electrical Characterization of High-Voltage Transformer Oils

    Science.gov (United States)

    Dervos, Constantine T.; Paraskevas, Christos D.; Skafidas, Panayotis D.; Vassiliou, Panayota

    2005-01-01

    This work investigates the use of a specially designed cylindrical metal cell, in order to obtain complex permittivity and tanδ data of highly insulating High Voltage (HV) transformer oil samples. The data are obtained at a wide range of frequencies and operation temperatures to demonstrate the polarization phenomena and the thermally stimulated effects. Such complex permittivity measurements may be utilized as a criterion for the service life prediction of oil field electrical equipment (OFEE). Therefore, by one set of measurements on a small oil volume, data may be provided on the impending termination, or continuation of the transformer oil service life. The oil incorporating cell, attached to the appropriate measuring units, could be described as a complex permittivity sensor. In this work, the acquired dielectric data from a great number of operating distribution network power transformers were correlated to corresponding physicochemical ones to demonstrate the future potential employment of the proposed measuring technique.

  19. Development and Field Test of Voltage VAR Optimization in the Korean Smart Distribution Management System

    Directory of Open Access Journals (Sweden)

    Sang-Yun Yun

    2014-02-01

    Full Text Available This paper is a summary of the development and demonstration of an optimization program, voltage VAR optimization (VVO, in the Korean Smart Distribution Management System (KSDMS. KSDMS was developed to address the lack of receptivity of distributed generators (DGs, standardization and compatibility, and manual failure recovery in the existing Korean automated distribution system. Focusing on the lack of receptivity of DGs, we developed a real-time system analysis and control program. The KSDMS VVO enhances manual system operation of the existing distribution system and provides a solution with all control equipment operated at a system level. The developed VVO is an optimal power flow (OPF method that resolves violations, minimizes switching costs, and minimizes loss, and its function can vary depending on the operator’s command. The sequential mixed integer linear programming (SMILP method was adopted to find the solution of the OPF. We tested the precision of the proposed VVO on selected simulated systems and its applicability to actual systems at two substations on the Jeju Island. Running the KSDMS VVO on a regular basis improved system stability, and it also raised no issues regarding its applicability to actual systems.

  20. Nano silver diffusion behaviour on conductive polymer during doping process for high voltage application

    Science.gov (United States)

    Mohammad, A.; Mahmood, A.; Chin, K. T.; Danquah, M. K.; van Stratan, S.

    2017-06-01

    Conductive polymer had opened a new era of engineering for microelectronics and semiconductor applications. However, it is still a challenge for high voltage applications due to lower electrical conductivity compare to metals. This results tremendous energy losses during transmission and restricts its usage. In order to address such problem a novel method was investigated using nano silver particle doped iodothiophene since silver is the highest electrical conductive material. The experiments were carried out to study the organometallic diffusion behaviour of nanosilver doped iodothiophene with different concentration of iodothiophene. Five different mixing ratio between nanosilver and the solution of iodothiophene dissolved in diethyl ether were used which are 1:1.25, 1:1.5, 1:2.5, 1:3 and l:5. It was revealed that there is an effective threshold concentration of which the nano silver evenly distributed and there was no coagulation observed. These parameters laid the foundation of better doping process between the nano silver and the polymer significantly which would contribute developing conductive polymer towards high voltage application for industries that are vulnerable to corrosive environment.

  1. Analysis and Comparison of Voltage Dependent Charging Strategies for Single-Phase Electric Vehicles in an Unbalanced Danish Distribution Grid

    DEFF Research Database (Denmark)

    Álvarez, Jorge Nájera; Knezovic, Katarina; Marinelli, Mattia

    2016-01-01

    This paper studies four voltage dependent solutions for modulating the charging of multiple Electric Vehicles (EVs) in a real Danish network. Uncontrolled EV charging, especially in grid with high EV penetration, can result in overloaded lines and transformers, low-voltages and other performance ...

  2. Distribution transformer with automatic voltage adjustment - performance; Transformador de distribucion con ajuste automatico de tension - desempeno

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez Ruiz, Gustavo A.; Delgadillo Bocanegra, Alfonso; Betancourt Ramirez, Enrique [PROLEC-GE, Apodaca, Nuevo Leon (Mexico)]. E-mail: gustavo1.hernandez@ge.com; alfonso.delgadillobocanegra@ge.com; enrique.betancourt@ge.com; Ramirez Arredondo, Juan M. [CINVESTAV-Guadalajara, Zapopan, Jalisco (Mexico)]. E-mail: jramirez@gdl.cinvestav.mx

    2010-11-15

    In the electric power distribution systems, the power quality is strongly linked with the service stability voltage. In the radial kind systems, it is virtually impossible to achieve a flat voltage along the lines, so it is desirable to count with transformers that can adjust automatically the turns ratio. In this work, it is described the development and the performance of a transformer with an integrated electronic tap changer, that allows to change the turns ratio along the standard range of +/-5%, and it was identified the application limits of the technology. [Spanish] En los sistemas de distribucion de energia electrica, la calidad del suministro de energia esta fuertemente ligada con la estabilidad del voltaje de servicio. En sistemas de tipo radial, es virtualmente imposible mantener uniforme la tension a lo largo de las lineas, por lo que se hace deseable contar con transformadores que puedan ajustar automaticamente la relacion de transformacion. En este trabajo, se describe el desarrollo y desempeno de un transformador con switch electronico integrado, que permite variar la relacion de transformacion dentro del rango estandarizado de +/-5%, y se identifican los limites de aplicacion de la tecnologia.

  3. Load Concentration Factor Based Analytical Method for Optimal Placement of Multiple Distribution Generators for Loss Minimization and Voltage Profile Improvement

    NARCIS (Netherlands)

    Shahzad, Mohsin; Ahmad, Ishtiaq; Gawlik, Wolfgang; Palensky, P.

    2016-01-01

    This paper presents novel separate methods for finding optimal locations, sizes of multiple distributed generators (DGs) simultaneously and operational power factor in order to minimize power loss and improve the voltage profile in the distribution system. A load concentration factor (LCF) is

  4. Efficient Parametric Identification Method for High Voltage Pulse Transformers

    CERN Document Server

    Aguglia, D; Viarouge, P; Cros, J

    2014-01-01

    This paper presents a new identification method for a pulse transformer equivalent circuit. It is based on an analytical approximation of the frequency-domain impedance data derived from a no-load test with open-circuited secondary winding and only requires measurements of primary current and voltage without phase data. Compared with time consuming and complex methods based on off-line non-linear identification procedures, this simple method also gives an estimation of the error on the identified parameters. The method is validated on an existing pulse transformer.

  5. Light-weight DC to very high voltage DC converter

    Science.gov (United States)

    Druce, R.L.; Kirbie, H.C.; Newton, M.A.

    1998-06-30

    A DC-DC converter capable of generating outputs of 100 KV without a transformer comprises a silicon opening switch (SOS) diode connected to allow a charging current from a capacitor to flow into an inductor. When a specified amount of charge has flowed through the SOS diode, it opens up abruptly; and the consequential collapsing field of the inductor causes a voltage and current reversal that is steered into a load capacitor by an output diode. A switch across the series combination of the capacitor, inductor, and SOS diode closes to periodically reset the SOS diode by inducing a forward-biased current. 1 fig.

  6. On-chip high-voltage generator design design methodology for charge pumps

    CERN Document Server

    Tanzawa, Toru

    2016-01-01

    This book provides various design techniques for switched-capacitor on-chip high-voltage generators, including charge pump circuits, regulators, level shifters, references, and oscillators.  Readers will see these techniques applied to system design in order to address the challenge of how the on-chip high-voltage generator is designed for Flash memories, LCD drivers, and other semiconductor devices to optimize the entire circuit area and power efficiency with a low voltage supply, while minimizing the cost.  This new edition includes a variety of useful updates, including coverage of power efficiency and comprehensive optimization methodologies for DC-DC voltage multipliers, modeling of extremely low voltage Dickson charge pumps, and modeling and optimum design of AC-DC switched-capacitor multipliers for energy harvesting and power transfer for RFID.

  7. Stray voltage mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Jamali, B.; Piercy, R.; Dick, P. [Kinetrics Inc., Toronto, ON (Canada). Transmission and Distribution Technologies

    2008-04-09

    This report discussed issues related to farm stray voltage and evaluated mitigation strategies and costs for limiting voltage to farms. A 3-phase, 3-wire system with no neutral ground was used throughout North America before the 1930s. Transformers were connected phase to phase without any electrical connection between the primary and secondary sides of the transformers. Distribution voltage levels were then increased and multi-grounded neutral wires were added. The earth now forms a parallel return path for the neutral current that allows part of the neutral current to flow continuously through the earth. The arrangement is responsible for causing stray voltage. Stray voltage causes uneven milk production, increased incidences of mastitis, and can create a reluctance to drink water amongst cows when stray voltages are present. Off-farm sources of stray voltage include phase unbalances, undersized neutral wire, and high resistance splices on the neutral wire. Mitigation strategies for reducing stray voltage include phase balancing; conversion from single to 3-phase; increasing distribution voltage levels, and changing pole configurations. 22 refs., 5 tabs., 13 figs.

  8. SiC heat pump converters with support for voltage unbalance in distribution grids

    DEFF Research Database (Denmark)

    Trintis, Ionut; Douglass, Philip; Maheshwari, Ramkrishan

    2015-01-01

    This paper studies the impact of involving the demand side of the LV grid into the grid conditioning process. Heat pumps are distribution loads with a substation capacity increase in the last years, with expectancy of growth in the coming years. Controlling the loads is the first step...... in the transition to smart grids, and heat pumps are to be the first promising smart loads. They can be used for load shedding but also for unbalance compensation purposes. When they are equipped with a back to back compressor drive and a proper control strategy, grid support can be provided to reduce the negative...... sequence component in the voltage at the installation point. Two control strategies are proposed and investigated experimentally on a SiC heat pump converter prototype....

  9. Differential distribution of voltage-gated ion channels in cortical neurons: implications for epilepsy.

    Science.gov (United States)

    Child, Nicholas D; Benarroch, Eduardo E

    2014-03-18

    Neurons contain different functional somatodendritic and axonal domains, each with a characteristic distribution of voltage-gated ion channels, synaptic inputs, and function. The dendritic tree of a cortical pyramidal neuron has 2 distinct domains, the basal and the apical dendrites, both containing dendritic spines; the different domains of the axon are the axonal initial segment (AIS), axon proper (which in myelinated axons includes the node of Ranvier, paranodes, juxtaparanodes, and internodes), and the axon terminals. In the cerebral cortex, the dendritic spines of the pyramidal neurons receive most of the excitatory synapses; distinct populations of γ-aminobutyric acid (GABA)ergic interneurons target specific cellular domains and thus exert different influences on pyramidal neurons. The multiple synaptic inputs reaching the somatodendritic region and generating excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs) sum and elicit changes in membrane potential at the AIS, the site of initiation of the action potential.

  10. Stochastic Dual Algorithm for Voltage Regulation in Distribution Networks with Discrete Loads: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Dall-Anese, Emiliano [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Zhou, Xinyang [University of Colorado; Liu, Zhiyuan [University of Colorado; Chen, Lijun [University of Colorado

    2017-10-03

    This paper considers distribution networks with distributed energy resources and discrete-rate loads, and designs an incentive-based algorithm that allows the network operator and the customers to pursue given operational and economic objectives, while concurrently ensuring that voltages are within prescribed limits. Four major challenges include: (1) the non-convexity from discrete decision variables, (2) the non-convexity due to a Stackelberg game structure, (3) unavailable private information from customers, and (4) different update frequency from two types of devices. In this paper, we first make convex relaxation for discrete variables, then reformulate the non-convex structure into a convex optimization problem together with pricing/reward signal design, and propose a distributed stochastic dual algorithm for solving the reformulated problem while restoring feasible power rates for discrete devices. By doing so, we are able to statistically achieve the solution of the reformulated problem without exposure of any private information from customers. Stability of the proposed schemes is analytically established and numerically corroborated.

  11. Results of the 2015 testbeam of a 180 nm AMS High-Voltage CMOS sensor prototype

    CERN Document Server

    Benoit, M.

    2016-07-21

    Active pixel sensors based on the High-Voltage CMOS technology are being investigated as a viable option for the future pixel tracker of the ATLAS experiment at the High-Luminosity LHC. This paper reports on the testbeam measurements performed at the H8 beamline of the CERN Super Proton Synchrotron on a High-Voltage CMOS sensor prototype produced in 180 nm AMS technology. Results in terms of tracking efficiency and timing performance, for different threshold and bias conditions, are shown.

  12. Urban exposure to ELF magnetic field due to high-, medium- and low-voltage electricity supply networks.

    Science.gov (United States)

    Bottura, V; Cappio Borlino, M; Carta, N; Cerise, L; Imperial, E

    2009-12-01

    The regional environment protection agency (ARPA) of the Aosta Valley region in north Italy performed a survey of magnetic field triggered by the power supply network in high, medium and low voltages on the entire area of Aosta town. The electrical distribution system for houses was not however taken into account. The aim of the survey was to evaluate the global population exposure and not simply the assessment of the legal exposure limit compliance.

  13. Preparation methodology and possible treatments for improved ceramics for high voltage vacuum applications

    CERN Document Server

    Tan, J

    1998-01-01

    The flashover characteristics of an insulator bridged high voltage vacuum gap can play an important role in the overall performance of a high voltage device, for example in the extreme environments of high energy particle accelerators. The detailed preparation of the insulators is, at present, governed by the commercial production methods and by standard bulk cleaning processes, which for a particular application may be far from optimum. The influence of the mechanical preparation, thermal history and particular cleaning technique have been investigated for commercially available alumina samples, with measurement of surface characteristics by scanning electron microscopy and laser diffraction, measurement of the secondary electron emission curve and analysis of the high voltage performance with the possibility of applied fields up to 200kV/cm. The results of the different measurements are discussed in the overall context of the problems encountered in the full sized high voltage devices, and suggestions are m...

  14. TCAD simulations of High-Voltage-CMOS Pixel structures for the CLIC vertex detector

    CERN Document Server

    Buckland, Matthew Daniel

    2016-01-01

    The requirements for precision physics and the experimental conditions at CLIC result in stringent constraints for the vertex detector. Capacitively coupled active pixel sensors with 25 μm pitch implemented in a commercial 180 nm High-Voltage CMOS (HV-CMOS) process are currently under study as a candidate technology for the CLIC vertex detector. Laboratory calibration measurements and beam tests with prototypes are complemented by detailed TCAD and electronic circuit simulations, aiming for a comprehensive understanding of the signal formation in the HV-CMOS sensors and subsequent readout stages. In this note 2D and 3D TCAD simulation results of the prototype sensor, the Capacitively Coupled Pixel Detector version three (CCPDv3), will be presented. These include the electric field distribution, leakage current, well capacitance, transient response to minimum ionising particles and charge-collection.

  15. Investigation of the Ampacity of a Prefabricated Straight-Through Joint of High Voltage Cable

    Directory of Open Access Journals (Sweden)

    Pengyu Wang

    2017-12-01

    Full Text Available This paper presents a theoretical and experimental study on the ampacity of the prefabricated straight-through joint of a 110 kV high voltage cable. Thermal modelling revealed that the critical spot limiting the ampacity of this type of cable joint is located on its crosslinked polyethylene (XLPE insulation section. The axial distribution of the thermal field in this type of cable joint was also determined. An algorithm for assessing ampacity in this type of cable joint was developed. Experiments were conducted on a real cable system with a prefabricated straight-through joint under different loading conditions. The experiments show a good agreement with the thermal modelling results.

  16. Efficiency Optimization by Considering the High Voltage Flyback Transformer Parasitics using an Automatic Winding Layout Technique

    DEFF Research Database (Denmark)

    Thummala, Prasanth; Schneider, Henrik; Zhang, Zhe

    2015-01-01

    .The energy efficiency is optimized using a proposed new automatic winding layout (AWL) technique and a comprehensive loss model.The AWL technique generates a large number of transformer winding layouts.The transformer parasitics such as dc resistance, leakage inductance and self-capacitance are calculated...... for each winding layout.An optimization technique is formulated to minimize the sum of energy losses during charge and discharge operations.The efficiency and energy loss distribution results from the optimization routine provide a deep insight into the high voltage transformer designand its impact...... on the total converter efficiency.The proposed efficiency optimization approach is experimentally verified on a25 W (average charging power) with100 W (peakpower) flyback dc-dc prototype....

  17. Effect of Doubly Fed Induction GeneratorTidal Current Turbines on Stability of a Distribution Grid under Unbalanced Voltage Conditions

    Directory of Open Access Journals (Sweden)

    Dahai Zhang

    2017-02-01

    Full Text Available This paper analyses the effects of doubly fed induction generator (DFIG tidal current turbines on a distribution grid under unbalanced voltage conditions of the grid. A dynamic model of an electrical power system under the unbalanced network is described in the paper, aiming to compare the system performance when connected with and without DFIG at the same location in a distribution grid. Extensive simulations of investigating the effect of DFIG tidal current turbine on stability of the distribution grid are performed, taking into account factors such as the power rating, the connection distance of the turbine and the grid voltage dip. The dynamic responses of the distribution system are examined, especially its ability to ride through fault events under unbalanced grid voltage conditions. The research has shown that DFIG tidal current turbines can provide a good damping performance and that modern DFIG tidal current power plants, equipped with power electronics and low-voltage ride-through capability, can stay connected to weak electrical grids even under the unbalanced voltage conditions, whilst not reducing system stability.

  18. An Annotated Bibliography of High-Voltage Direct-Current Transmission and Flexible AC Transmission (FACTS) Devices, 1991-1993.

    Energy Technology Data Exchange (ETDEWEB)

    Litzenberger, Wayne; Lava, Val

    1994-08-01

    References are contained for HVDC systems, converter stations and components, overhead transmission lines, cable transmission, system design and operations, simulation of high voltage direct current systems, high-voltage direct current installations, and flexible AC transmission system (FACTS).

  19. Quantum-well charge and voltage distribution in a metal–insulator–semiconductor structure upon resonant electron Tunneling

    Energy Technology Data Exchange (ETDEWEB)

    Vexler, M. I., E-mail: vexler@mail.ioffe.ru; Illarionov, Yu. Yu.; Grekhov, I. V. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation)

    2017-04-15

    The prerequisites for electron storage in the quantum well of a metal–oxide–p{sup +}-Si resonant-tunneling structure and the effect of the stored charge on the voltage distribution are theoretically investigated. Systems with SiO{sub 2}, HfO{sub 2}, and TiO{sub 2} insulators are studied. It is demonstrated that the occurrence of a charge in the well in the case of resonant transport can be expected in structures on substrates with an acceptor concentration from (5–6) × 10{sup 18} to (2–3) × 10{sup 19} cm{sup –3} in the range of oxide thicknesses dependent on this concentration. In particular, the oxide layer thickness in the structures with SiO{sub 2}/p{sup +}-Si(10{sup 19} cm{sup –3}) should exceed ~3 nm. The electron density in the well can reach ~10{sup 12} cm{sup –2} and higher. However, the effect of this charge on the electrostatics of the structure becomes noticeable only at relatively high voltages far above the activation of resonant transport through the first subband.

  20. Insulation co-ordination in high-voltage electric power systems

    CERN Document Server

    Diesendorf, W

    2015-01-01

    Insulation Co-ordination in High-Voltage Electric Power Systems deals with the methods of insulation needed in different circumstances. The book covers topics such as overvoltages and lightning surges; disruptive discharge and withstand voltages; self-restoring and non-self-restoring insulation; lightning overvoltages on transmission lines; and the attenuation and distortion of lightning surges. Also covered in the book are topics such as the switching surge designs of transmission lines, as well as the insulation coordination of high-voltage stations. The text is recommended for electrical en

  1. Bidirectional Flyback Converter with Multiple Series Connected Outputs for High Voltage Capacitive Charge and Discharge Applications

    DEFF Research Database (Denmark)

    Thummala, Prasanth; Schneider, Henrik; Zhang, Zhe

    2015-01-01

    V) in series with a high voltage blocking diode is added, in parallel with a high voltage freewheeling diode of a conventional flyback topology, to enable bidirectional operation. Experimental result from a digitally controlled bidirectional flyback converter shows that the discharge energy efficiency...... by lower voltage rating MOSFETs driven by a gate drive transformer. Simulation results to compare the operation of conventional and proposed converters are provided. The advantages of proposed implementation are improved energy efficiency and lower cost. Experimental results with two series connected...

  2. A Sepic-Type Single-Stage Electronic Ballast for High Line Voltage Applications

    Science.gov (United States)

    Shen, Chih-Lung; Chen, Kuo-Kuang

    In this paper, a sepic-type single-stage electronic ballast (STSSEB) is proposed, which is derived from the combination of a sepic converter and a half-bridge inverter. The ballast can not only step down input voltage directly but achieve high power factor, reduce voltage stress, improve efficiency and lower cost. Since component stress is reduced significantly, the presented ballast can be applied to high voltage mains. Derivation of the STSSEB is first presented. Then, analysis, design and practical consideration for the STSSEB are discussed. A 347Vac 60W prototype has been simulated and implemented. Simulations and experimental results have verified the feasibility of the proposed STSSEB.

  3. A high voltage gain quasi Z-source isolated DC/DC converter

    DEFF Research Database (Denmark)

    Siwakoti, Yam P.; Blaabjerg, Frede; Loh, Poh Chiang

    2014-01-01

    by a voltage doubling output rectifier. The converter is well-suited to applications requiring a high voltage gain, especially renewable energy sources such as photovoltaic and fuel-cell power supplies. To demonstrate the converter's performance a prototype designed to output 400 V at 500 W was constructed......A compact quasi-Z-source DC/DC converter is presented with high voltage gain, isolated output, and improved efficiency. The improvements in size and performance were achieved by using a square wave inverter with only two output switches driving an isolating transformer in push-pull mode, followed...

  4. A low knee voltage and high breakdown voltage of 4H-SiC TSBS employing poly-Si/Ni Schottky scheme

    Science.gov (United States)

    Kim, Dong Young; Seok, Ogyun; Park, Himchan; Bahng, Wook; Kim, Hyoung Woo; Park, Ki Cheol

    2018-02-01

    We report a low knee voltage and high breakdown voltage 4H-SiC TSBS employing poly-Si/Ni dual Schottky contacts. A knee voltage was significantly improved from 0.75 to 0.48 V by utilizing an alternative low work-function material of poly-Si as an anode electrode. Also, reverse breakdown voltage was successfully improved from 901 to 1154 V due to a shrunk low-work-function Schottky region by a proposed self-align etching process between poly-Si and SiC. SiC TSBS with poly-Si/Ni dual Schottky scheme is a suitable structure for high-efficiency rectification and high-voltage blocking operation.

  5. Coordination of voltage and reactive power control in the extra high voltage substations based on the example of solutions applied in the national power system

    Directory of Open Access Journals (Sweden)

    Dariusz Kołodziej

    2012-06-01

    Full Text Available This paper presents examples of coordination between automatic voltage and reactive power control systems (ARST covering adjacent and strongly related extra high voltage substations. Included are conclusions resulting from the use of these solutions. The Institute of Power Engineering, Gdańsk Division has developed and deployed ARST systems in the national power system for a dozen or so years.

  6. A high voltage, constant current stimulator for electrocutaneous stimulation through small electrodes.

    Science.gov (United States)

    Poletto, C J; Van Doren, C L

    1999-08-01

    A high-voltage stimulator has been designed to allow transcutaneous stimulation of tactile fibers of the fingertip. The stimulator's output stage was based upon an improved Howland current pump topology, modified to allow high load impedances and small currents. The compliance voltage of approximately 800 V is achieved using commercially available high-voltage operational amplifiers. The output current accuracy is better than +/- 5% over the range of 1 to 25 mA for 30 microseconds or longer pulses. The rise time for square pulses is less than 1 microsecond. High-voltage, common-mode, latch-up power supply problems and solutions are discussed. The stimulator's input stage is optically coupled to the controlling computer and complies with applicable safety standards for use in a hospital environment. The design presented here is for monophasic stimulation only, but could be modified for biphasic stimulation.

  7. Demonstration of the two-chamber approach for high-voltage measurements using collinear laser spectroscopy

    Science.gov (United States)

    Will, Elisa; Ullmann, Johannes; Frömmgen, Nadja; Geppert, Christopher; Gorges, Christian; Hammen, Michael; Kaufmann, Simon; Krieger, Andreas; Nörtershäuser, Wilfried

    2014-06-01

    An electronic measurement of high-voltages of several ten kV with accuracy as required for precision experiments is currently only feasible using highly sophisticated voltage dividers. Collinear laser spectroscopy can provide a direct and precise measurement of high-voltages using the Doppler shift of accelerated ions. Although proposed already in 1982, a measurement with relative accuracy better than 10-4 was not reported so far. To improve this accuracy, a dedicated new setup for high-voltage measurements will be installed at the Technische Universität Darmstadt. A two-chamber approach will be used to remove uncertainties due to the insufficiently known starting potential inside the ion source. Here we present a demonstration of the pump-and-probe technique performed in preparatory studies at the TRIGA-LASER experiment in Mainz.

  8. Project resumes: biological effects from electric fields associated with high-voltage transmission lines

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-01-01

    Abstracts of research projects are presented in the following areas: measurements and special facilities; cellular and subcellular studies; physiology; behavior; environmental effects; modeling, scaling and dosimetry; and high voltage direct current. (ACR)

  9. Lithium-Ion Electrolytes with Improved Safety Tolerance to High Voltage Systems

    Science.gov (United States)

    Smart, Marshall C. (Inventor); Bugga, Ratnakumar V. (Inventor); Prakash, Surya G. (Inventor); Krause, Frederick C. (Inventor)

    2015-01-01

    The invention discloses various embodiments of electrolytes for use in lithium-ion batteries, the electrolytes having improved safety and the ability to operate with high capacity anodes and high voltage cathodes. In one embodiment there is provided an electrolyte for use in a lithium-ion battery comprising an anode and a high voltage cathode. The electrolyte has a mixture of a cyclic carbonate of ethylene carbonate (EC) or mono-fluoroethylene carbonate (FEC) co-solvent, ethyl methyl carbonate (EMC), a flame retardant additive, a lithium salt, and an electrolyte additive that improves compatibility and performance of the lithium-ion battery with a high voltage cathode. The lithium-ion battery is charged to a voltage in a range of from about 2.0 V (Volts) to about 5.0 V (Volts).

  10. Spontaneous aggregation of lithium ion coordination polymers in fluorinated electrolytes for high-voltage batteries.

    Science.gov (United States)

    Malliakas, Christos D; Leung, Kevin; Pupek, Krzysztof Z; Shkrob, Ilya A; Abraham, Daniel P

    2016-04-28

    Fluorinated carbonates are pursued as liquid electrolyte solvents for high-voltage Li-ion batteries. Here we report aggregation of [Li(+)(FEC)3]n polymer species in fluoroethylene carbonate containing electrolytes and scrutinize the causes for this behavior.

  11. AC Voltage Control of DC/DC Converters Based on Modular Multilevel Converters in Multi-Terminal High-Voltage Direct Current Transmission Systems

    Directory of Open Access Journals (Sweden)

    Rui Li

    2016-12-01

    Full Text Available The AC voltage control of a DC/DC converter based on the modular multilevel converter (MMC is considered under normal operation and during a local DC fault. By actively setting the AC voltage according to the two DC voltages of the DC/DC converter, the modulation index can be near unity, and the DC voltage is effectively utilized to output higher AC voltage. This significantly decreases submodule (SM capacitance and conduction losses of the DC/DC converter, yielding reduced capital cost, volume, and higher efficiency. Additionally, the AC voltage is limited in the controllable range of both the MMCs in the DC/DC converter; thus, over-modulation and uncontrolled currents are actively avoided. The AC voltage control of the DC/DC converter during local DC faults, i.e., standby operation, is also proposed, where only the MMC connected on the faulty cable is blocked, while the other MMC remains operational with zero AC voltage output. Thus, the capacitor voltages can be regulated at the rated value and the decrease of the SM capacitor voltages after the blocking of the DC/DC converter is avoided. Moreover, the fault can still be isolated as quickly as the conventional approach, where both MMCs are blocked and the DC/DC converter is not exposed to the risk of overcurrent. The proposed AC voltage control strategy is assessed in a three-terminal high-voltage direct current (HVDC system incorporating a DC/DC converter, and the simulation results confirm its feasibility.

  12. Risk assessment of desert pollution on composite high voltage insulators.

    Science.gov (United States)

    El-Shahat, Mohammed; Anis, Hussein

    2014-09-01

    Transmission lines located in the desert are subjected to desert climate, one of whose features is sandstorms. With long accumulation of sand and with the advent of moisture from rain, ambient humidity and dew, a conductive layer forms and the subsequent leakage current may lead to surface discharge, which may shorten the insulator life or lead to flashover thus interrupting the power supply. Strategically erected power lines in the Egyptian Sinai desert are typically subject to such a risk, where sandstorms are known to be common especially in the spring. In view of the very high cost of insulator cleaning operation, composite (silicon rubber) insulators are nominated to replace ceramic insulators on transmission lines in Sinai. This paper examines the flow of leakage current on sand-polluted composite insulators, which in turn enables a risk assessment of insulator failure. The study uses realistic data compiled and reported in an earlier research project about Sinai, which primarily included grain sizes of polluting sand as well as their salinity content. The paper also uses as a case study an ABB-designed composite insulator. A three-dimensional finite element technique is used to simulate the insulator and seek the potential and electric field distribution as well as the resulting leakage current flow on its polluted surface. A novel method is used to derive the probabilistic features of the insulator's leakage current, which in turn enables a risk assessment of insulator failure. This study is expected to help in critically assessing - and thus justifying - the use of this type of insulators in Sinai and similar critical areas.

  13. Risk assessment of desert pollution on composite high voltage insulators

    Directory of Open Access Journals (Sweden)

    Mohammed El-Shahat

    2014-09-01

    Full Text Available Transmission lines located in the desert are subjected to desert climate, one of whose features is sandstorms. With long accumulation of sand and with the advent of moisture from rain, ambient humidity and dew, a conductive layer forms and the subsequent leakage current may lead to surface discharge, which may shorten the insulator life or lead to flashover thus interrupting the power supply. Strategically erected power lines in the Egyptian Sinai desert are typically subject to such a risk, where sandstorms are known to be common especially in the spring. In view of the very high cost of insulator cleaning operation, composite (silicon rubber insulators are nominated to replace ceramic insulators on transmission lines in Sinai. This paper examines the flow of leakage current on sand-polluted composite insulators, which in turn enables a risk assessment of insulator failure. The study uses realistic data compiled and reported in an earlier research project about Sinai, which primarily included grain sizes of polluting sand as well as their salinity content. The paper also uses as a case study an ABB-designed composite insulator. A three-dimensional finite element technique is used to simulate the insulator and seek the potential and electric field distribution as well as the resulting leakage current flow on its polluted surface. A novel method is used to derive the probabilistic features of the insulator’s leakage current, which in turn enables a risk assessment of insulator failure. This study is expected to help in critically assessing – and thus justifying – the use of this type of insulators in Sinai and similar critical areas.

  14. Detailed Behavior Analysis for High Voltage Bidirectional Flyback Converter Driving DEAP Actuator

    DEFF Research Database (Denmark)

    Huang, Lina; Zhang, Zhe; Andersen, Michael A. E.

    2013-01-01

    flyback based converter has been implemented. The parasitic elements have serious influence for the operation of the converter, especially in the high output voltage condition. The detailed behavior analysis has been performed considering the impact of the critical parasitic parameters. The converter has...... been analyzed for both charging and discharging processes in low and high output voltage operating occasions. The experimental waveforms can validate the analysis....

  15. Preparation and characterization of EPDM-silica nano/micro composites for high voltage insulation applications

    OpenAIRE

    Ali Muhammad; Choudhry Muhammad Ahmad

    2015-01-01

    The rising market for substitute materials in high voltage insulation components is stimulated largely by the need to reduce overall costs. In this respect, polymer insulators offer significant advantages over old traditional materials. In the present research, efforts have been made to quantify the effect of silica (having different particle size nano, micro and hybrid) loading on the mechanical and thermal behaviors of Ethylene-Propylene-Diene Monomer (EPDM) based high voltage electrical in...

  16. Static Electricity as Part of Electromagnetic Environment on High-Voltage Electrical Substation

    Directory of Open Access Journals (Sweden)

    M. I. Fursanov

    2012-01-01

    Full Text Available Causes of occurrences electrostatic discharges (ESD on high-voltage electric substation were investigated and dependences values ESD’s on parameters interaction structures, humidity of air were found. Experimental research values ESD’s on high-voltage electric substation and in man-made conditions was fulfilled. Uncertainty measurement’s was taken into consideration by research results analyze. Matching with research of other authors was made. Danger ESD’s for electric devises was established.

  17. High-voltage electroporation of bacteria: genetic transformation of Campylobacter jejuni with plasmid DNA.

    OpenAIRE

    Miller, J F; Dower, W J; Tompkins, L S

    1988-01-01

    Electroporation permits the uptake of DNA by mammalian cells and plant protoplasts because it induces transient permeability of the cell membrane. We investigated the utility of high-voltage electroporation as a method for genetic transformation of intact bacterial cells by using the enteric pathogen Campylobacter jejuni as a model system. This report demonstrates that the application of high-voltage discharges to bacterial cells permits genetic transformation. Our method involves exposure of...

  18. Analysis and mitigation of external factors induced failures in high voltage equipment

    OpenAIRE

    AKALP, Onur; Kaya, İbrahim; Efe, Serhat Berat

    2016-01-01

    In this study, insulators and switchyard equipment with porcelain outer surface with the most experienced equipment failures in high voltage power systems have been investigated. The effects of the external environment cause malfunctions in these equipments are determined. Due to the external environment effects failures occurring in equipment were examined. Firstly, high-voltage switchgear equipments which are the subject of study are explained. These include circuit breakers, disconnectors,...

  19. A New Approach to High Efficincy in Isolated Boost Converters for High-Power Low-Voltage Fuel Cell Apllications

    DEFF Research Database (Denmark)

    Nymand, Morten; Andersen, Michael A. E.

    2008-01-01

    A new low-leakage-inductance low-resistance design approach to low-voltage high-power isolated boost converters is presented. Very low levels of parasitic circuit inductances are achieved by optimizing transformer design and circuit lay-out. Primary side voltage clamp circuits can be eliminated b...

  20. Design and Development of Autonomous High Voltage Driving System for DEAP Actuator in Radiator Thermostat

    DEFF Research Database (Denmark)

    Huang, Lina; Zhang, Zhe; Andersen, Michael A. E.

    2014-01-01

    make a high voltage capacitive load driving system to be necessary. The only energy source battery determines it needs to be an autonomous system. The detailed system specifications have been introduced and the corresponding system level design has been proposed. In addition, the detailed design......In radiator thermostat applications, DEAP (Dielectric Electro Active Polymer) actuator tends to be a good candidate to replace the conventional self-actuating or step motor based actuator due to its intrinsic advantages. The capacitive property and high voltage (HV) driving demand of DEAP actuator...... and implementation information has been provided as well, including the power and control stage inside the high voltage converter, the output voltage measurement circuit, the feedback control, etc. Finally, the experimental results have been provided to validate the capability and performance of the driving system....

  1. Environmental and biotechnological applications of high-voltage pulsed discharges in water

    Science.gov (United States)

    Sato, Masayuki

    2008-05-01

    A high-voltage pulse has wide application in fields such as chemistry, physics and biology and their combinations. The high-voltage pulse forms two kinds of physical processes in water, namely (a) a pulsed electric field (PEF) in the parallel electrode configuration and (b) plasma generation by a pulsed discharge in the water phase with a concentrated electric field. The PEF can be used for inactivation of bacteria in liquid foods as a non-thermal process, and the underwater plasma is applicable not only for the decomposition of organic materials in water but also for biological treatment of wastewater. These discharge states are controlled mainly by the applied pulse voltage and the electrode shape. Some examples of environmental and biotechnological applications of a high-voltage pulse are reviewed.

  2. Self-Healable Electrical Insulation for High Voltage Applications

    Science.gov (United States)

    Williams, Tiffany S.

    2017-01-01

    Polymeric aircraft electrical insulation normally degrades by partial discharge with increasing voltage, which causes excessive localized Joule heating in the material and ultimately leads to dielectric failure of the insulator through thermal breakdown. Developing self-healing insulation could be a viable option to mitigate permanent mechanical degradation, thus increasing the longevity of the insulation. Instead of relying on catalyst and monomer-filled microcapsules to crack, flow, and cure at the damaged sites described in well-published mechanisms, establishment of ionic crosslinks could allow for multiple healing events to occur with the added benefit of achieving full recovery strength under certain thermal environments. This could be possible if the operating temperature of the insulator is the same as or close to the temperature where ionic crosslinks are formed. Surlyn, a commercial material with ionic crosslinks, was investigated as a candidate self-healing insulator based off prior demonstrations of self-healing behavior. Thin films of varying thicknesses were investigated and the effects of thickness on the dielectric strength were evaluated and compared to representative polymer insulators. The effects of thermal conditioning on the recovery strength and healing were observed as a function of time following dielectric breakdown. Moisture absorption was also studied to determine if moisture absorption rates in Surlyn were lower than that of common polyimides.

  3. Modulation of High-Voltage Activated Ca2+ Channels by Membrane Phosphatidylinositol 4,5-Bisphosphate

    Science.gov (United States)

    Suh, Byung-Chang; Leal, Karina; Hille, Bertil

    2010-01-01

    SUMMARY Modulation of voltage-gated Ca2+ channels controls activities of excitable cells. We show that high-voltage activated Ca2+ channels are regulated by membrane phosphatidylinositol 4,5-bisphosphate (PIP2) with different sensitivities. Plasma membrane PIP2 depletion by rapamycin-induced translocation of an inositol lipid 5-phosphatase or by a voltage-sensitive 5-phosphatase (VSP) suppresses CaV1.2 and CaV1.3 channel currents by ~35%, and CaV2.1 and CaV2.2 currents by 29 and 55%, respectively. Other CaV channels are less sensitive. Inhibition is not relieved by strong depolarizing prepulses. It changes the voltage dependence of channel gating little. Recovery of currents from inhibition needs intracellular hydrolysable ATP, presumably for PIP2 resynthesis. When PIP2 is increased by overexpressing PIP 5-kinase, activation and inactivation of CaV2.2 current slow and voltage-dependent gating shifts to slightly higher voltages. Thus, endogenous membrane PIP2 supports high-voltage activated L-, N-, and P/Q- type Ca2+ channels, and stimuli that activate phospholipase C deplete PIP2 and reduce those Ca2+ channel currents. PMID:20670831

  4. Photovoltaic Impact Assessment of Smart Inverter Volt-VAR Control on Distribution System Conservation Voltage Reduction and Power Quality

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Fei [National Renewable Energy Lab. (NREL), Golden, CO (United States); Nagarajan, Adarsh [National Renewable Energy Lab. (NREL), Golden, CO (United States); Chakraborty, Sudipta [National Renewable Energy Lab. (NREL), Golden, CO (United States); Baggu, Murali [National Renewable Energy Lab. (NREL), Golden, CO (United States); Nguyen, Andu [SolarCity, San Mateo, CA (United States); Walinga, Sarah [SolarCity, San Mateo, CA (United States); McCarty, Michael [SolarCity, San Mateo, CA (United States); Bell, Frances [SolarCity, San Mateo, CA (United States)

    2016-12-01

    This report presents an impact assessment study of distributed photovoltaic (PV) with smart inverter Volt-VAR control on conservation voltage reduction (CVR) energy savings and distribution system power quality. CVR is a methodology of flattening and lowering a distribution system voltage profile in order to conserve energy. Traditional CVR relies on operating utility voltage regulators and switched capacitors. However, with the increased penetration of distributed PV systems, smart inverters provide the new opportunity to control local voltage and power factor by regulating the reactive power output, leading to a potential increase in CVR energy savings. This report proposes a methodology to implement CVR scheme by operating voltage regulators, capacitors, and autonomous smart inverter Volt-VAR control in order to achieve increased CVR benefit. Power quality is an important consideration when operating a distribution system, especially when implementing CVR. It is easy to measure the individual components that make up power quality, but a comprehensive method to incorporate all of these values into a single score has yet to be undertaken. As a result, this report proposes a power quality scoring mechanism to measure the relative power quality of distribution systems using a single number, which is aptly named the 'power quality score' (PQS). Both the CVR and PQS methodologies were applied to two distribution system models, one obtained from the Hawaiian Electric Company (HECO) and another obtained from Pacific Gas and Electric (PG&E). These two models were converted to the OpenDSS platform using previous model conversion tools that were developed by NREL. Multiple scenarios including various PV penetration levels and smart inverter densities were simulated to analyze the impact of smart inverter Volt-VAR support on CVR energy savings and feeder power quality. In order to analyze the CVR benefit and PQS, an annual simulation was conducted for each

  5. Voltage magnitude and margin controller for remote industrial microgrid with high wind penetration

    DEFF Research Database (Denmark)

    Cai, Yu; Lin, Jin; Song, Yonghua

    2013-01-01

    It is well known that the remote industrial microgrid is located at the periphery of the grid, which is weakly connected to the main grid. In order to enhance the voltage stability and ensure a good power quality for industries, a voltage magnitude and margin controller based on wind turbines...... is proposed in this paper. This controller includes two parts to improve voltage stability in different time scales by using local measurements. Case studies conducted for a remote microgrid with high wind penetration have proved the effectiveness of the proposed control scheme....

  6. A Novel Quasi-SEPIC High-Voltage Boost DC-DC Converter

    DEFF Research Database (Denmark)

    Siwakoti, Yam Prasad; N. Soltani, Mohsen; Blaabjerg, Frede

    2017-01-01

    This paper proposes a modified coupled-inductor SEPIC dc-dc converter for low power and high voltage gain applications such as for piezoelectric drive systems. The converter uses the same components as of SEPIC converter with an additional diode. Compared to conventional topologies with similar...... voltage gain expression, the proposed topology uses less components to achieve same or even higher voltage gain. This helps to design a very compact and light weight converter with higher power density at lower cost. Due to brevity, the principle of operation, theoretical analysis and comparison supported...

  7. Behavior of AC High Voltage Polyamide Insulators: Evolution of Leakage Current in Different Surface Conditions

    OpenAIRE

    Mohammed El Amine Slama; Abderrahmane Beroual

    2015-01-01

    This paper is aimed at a systematic study of the leakage current of high voltage polyamide insulator string under different conditions of pollution for possible application in the electric locomotive systems. It is shown that in the case of clean/dry and clean/wetted insulators, the leakage current and applied voltage are linear. While in the case of pollution with saline spray, the leakage current and the applied voltage are not linear; the leakage current changes from a linear regime to a n...

  8. Behavior of AC High Voltage Polyamide Insulators: Evolution of Leakage Current in Different Surface Conditions

    Directory of Open Access Journals (Sweden)

    Mohammed El Amine Slama

    2015-01-01

    Full Text Available This paper is aimed at a systematic study of the leakage current of high voltage polyamide insulator string under different conditions of pollution for possible application in the electric locomotive systems. It is shown that in the case of clean/dry and clean/wetted insulators, the leakage current and applied voltage are linear. While in the case of pollution with saline spray, the leakage current and the applied voltage are not linear; the leakage current changes from a linear regime to a nonlinear regime up to total flashover of the insulators sting. Traces of erosion and tracking of insulators resulting of partial discharges are observed.

  9. A stochastic model of gamma-ray induced oxide charge distribution and threshold voltage shift of MOS transistors

    Directory of Open Access Journals (Sweden)

    Kevkić Tijana S.

    2012-01-01

    Full Text Available A stochastic model of gamma-ray radiation effects on the density of the induced charge in silicon dioxide films of MOS transistors is presented in this paper. It is assumed that both radiation induced charge generation and trapped charge recombination are stochastic processes. For estimating gamma-ray induced charges spatially distributed in silicon dioxide films, a procedure similar to the Monte Carlo method was used. The proposed model implemented in the programming language MATHEMATICA enables us, for the first time, to show the gamma-ray induced charge distribution as a function of gamma-ray doses. Using the developed model, we have also calculated the corresponding threshold voltage shifts of MOS transistors. These results were compared with the experimentally determined threshold voltage shift of MOS transistors with different voltages applied during irradiation vs. gamma radiation doses. Satisfactory agreements were obtained.

  10. High-Voltage, High-Power Gaseous Electronics Switch For Electric Grid Power Conversion

    Science.gov (United States)

    Sommerer, Timothy J.

    2014-05-01

    We are developing a high-voltage, high-power gas switch for use in low-cost power conversion terminals on the electric power grid. Direct-current (dc) power transmission has many advantages over alternating current (ac) transmission, but at present the high cost of ac-dc power interconversion limits the use of dc. The gas switch we are developing conducts current through a magnetized cold cathode plasma in hydrogen or helium to reach practical current densities > 1 A/cm2. Thermal and sputter damage of the cathode by the incident ion flux is a major technical risk, and is being addressed through use of a ``self-healing'' liquid metal cathode (eg, gallium). Plasma conditions and cathode sputtering loss are estimated by analyzing plasma spectral emission. A particle-in-cell plasma model is used to understand various aspects of switch operation, including the conduction phase (where plasma densities can exceed 1013 cm-3), the switch-open phase (where the high-voltage must be held against gas breakdown on the left side of Paschen's curve), and the switching transitions (especially the opening process, which is initiated by forming an ion-matrix sheath adjacent to a control grid). The information, data, or work presented herein was funded in part by the Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR0000298.

  11. Controlled operation of the Islanded portion of the CIGRE Low Voltage distribution network

    DEFF Research Database (Denmark)

    Mustafa, Ghullam; Bak, Claus Leth; Ali, Ehsan

    2017-01-01

    in islanding condition. Under normal operating conditions the control system of each DG unit operates in either active-reactive power (PQ) or active power-voltage (PV) control mode. When MG is cut-off from the main grid, the DG units must detect this islanding condition and one of the controllers should...... manner by providing some ancillary services. The main focus of this paper is about the development of a control system for the islanded MG, the selection of Voltage-Frequency (VF) controller for the most suitable DG unit of the Low Voltage (LV) test network and the control of voltage and frequency...

  12. A Novel Transformerless DC–DC Converters With High Step-Up Voltage Gain And Low Voltage Stress On The Switch

    Directory of Open Access Journals (Sweden)

    hossein ajdarfaeghi

    2016-10-01

    Full Text Available In this paper, a single switch transformerless high step up dc-dc converter with low voltage stress on the switch is proposed. In the proposed converter only one switch is used which makes the control scheme simple as well as reducing the switching power loss. The voltage gain of the proposed converter is higher than the conventional boost converter and buck boost converter and Proposed converter works in wide rang than conventional converters. The proposed converter has low voltage stress on the switch which makes reducing the switching power loss. The proposed converter can be operated in the continuous conduction mode (CCM and the discontinuous conduction mode (DCM. In this paper, different operation modes of the proposed converter, calculation of the voltage gain, the currents that flow through the components, efficiency and capacitors voltage ripple are presented. To verify the operation of the proposed converter, simulation results via PSCAD software and experimental results are provided.

  13. Derivation of Parabolic Current Control with High Precision, Fast Convergence and Extended Voltage Control Application

    OpenAIRE

    Zhang, Lanhua

    2016-01-01

    Current control is an important topic in modern power electronics system. For voltage source inverters, current control loop ensures the waveform quality at steady state and the fast response at transient state. To improve the current control performance, quite a few nonlinear control strategies have been presented and one well-known strategy is the hysteresis current control. It achieves fast response without stability issue and it has high control precision. However, for voltage source inve...

  14. Simulation models developed for voltage control in a distribution network using energy storage systems for PV penetration

    DEFF Research Database (Denmark)

    Mihet-Popa, Lucian; Bindner, Henrik W.

    2013-01-01

    This paper presents the development of simulation models for DER components in a distribution network, with focus on voltage controllers using energy storage systems for PV penetration. The Vanadium Redox Battery (VRB) system model, used as an energy storage system, was implemented in MATLAB...

  15. FPGA-based voltage and current dual drive system for high frame rate electrical impedance tomography.

    Science.gov (United States)

    Khan, Shadab; Manwaring, Preston; Borsic, Andrea; Halter, Ryan

    2015-04-01

    Electrical impedance tomography (EIT) is used to image the electrical property distribution of a tissue under test. An EIT system comprises complex hardware and software modules, which are typically designed for a specific application. Upgrading these modules is a time-consuming process, and requires rigorous testing to ensure proper functioning of new modules with the existing ones. To this end, we developed a modular and reconfigurable data acquisition (DAQ) system using National Instruments' (NI) hardware and software modules, which offer inherent compatibility over generations of hardware and software revisions. The system can be configured to use up to 32-channels. This EIT system can be used to interchangeably apply current or voltage signal, and measure the tissue response in a semi-parallel fashion. A novel signal averaging algorithm, and 512-point fast Fourier transform (FFT) computation block was implemented on the FPGA. FFT output bins were classified as signal or noise. Signal bins constitute a tissue's response to a pure or mixed tone signal. Signal bins' data can be used for traditional applications, as well as synchronous frequency-difference imaging. Noise bins were used to compute noise power on the FPGA. Noise power represents a metric of signal quality, and can be used to ensure proper tissue-electrode contact. Allocation of these computationally expensive tasks to the FPGA reduced the required bandwidth between PC, and the FPGA for high frame rate EIT. In 16-channel configuration, with a signal-averaging factor of 8, the DAQ frame rate at 100 kHz exceeded 110 frames s (-1), and signal-to-noise ratio exceeded 90 dB across the spectrum. Reciprocity error was found to be for frequencies up to 1 MHz. Static imaging experiments were performed on a high-conductivity inclusion placed in a saline filled tank; the inclusion was clearly localized in the reconstructions obtained for both absolute current and voltage mode data.

  16. Fast response double series resonant high-voltage DC-DC converter

    Science.gov (United States)

    Lee, S. S.; Iqbal, S.; Kamarol, M.

    2012-10-01

    In this paper, a novel double series resonant high-voltage dc-dc converter with dual-mode pulse frequency modulation (PFM) control scheme is proposed. The proposed topology consists of two series resonant tanks and hence two resonant currents flow in each switching period. Moreover, it consists of two high-voltage transformer with the leakage inductances are absorbed as resonant inductor in the series resonant tanks. The secondary output of both transformers are rectified and mixed before supplying to load. In the resonant mode operation, the series resonant tanks are energized alternately by controlling two Insulated Gate Bipolar Transistor (IGBT) switches with pulse frequency modulation (PFM). This topology operates in discontinuous conduction mode (DCM) with all IGBT switches operating in zero current switching (ZCS) condition and hence no switching loss occurs. To achieve fast rise in output voltage, a dual-mode PFM control during start-up of the converter is proposed. In this operation, the inverter is started at a high switching frequency and as the output voltage reaches 90% of the target value, the switching frequency is reduced to a value which corresponds to the target output voltage. This can effectively reduce the rise time of the output voltage and prevent overshoot. Experimental results collected from a 100-W laboratory prototype are presented to verify the effectiveness of the proposed system.

  17. Response characteristic of high-speed on/off valve with double voltage driving circuit

    Science.gov (United States)

    Li, P. X.; Su, M.; Zhang, D. B.

    2017-07-01

    High-speed on/off valve, an important part of turbocharging system, its quick response has a direct impact on the turbocharger pressure cycle. The methods of improving the response characteristic of high speed on/off valve include increasing the magnetic force of armature and the voltage, decreasing the mass and current of coil. The less coil number of turns, the solenoid force is smaller. The special armature structure and the magnetic material will raise cost. In this paper a new scheme of double voltage driving circuit is investigated, in which the original driving circuit of high-speed on/off valve is replaced by double voltage driving circuit. The detailed theoretical analysis and simulations were carried out on the double voltage driving circuit, it showed that the switching time and delay time of the valve respectively are 3.3ms, 5.3ms, 1.9ms and 1.8ms. When it is driven by the double voltage driving circuit, the switching time and delay time of this valve are reduced, optimizing its response characteristic. By the comparison related factors (such as duty cycle or working frequency) about influences on response characteristic, the superior of double voltage driving circuit has been further confirmed.

  18. Generic inertia emulation controller for multi-terminal voltage-source-converter high voltage direct current systems

    DEFF Research Database (Denmark)

    Zhu, Jiebei; Guerrero, Josep M.; Hung, William

    2014-01-01

    A generic Inertia Emulation Controller (INEC) scheme for Multi-Terminal Voltage-Source-Converter based HVDC (VSC-MTDC) systems is proposed and presented in this paper. The proposed INEC can be incorporated in any Grid-side Voltage-Source-Converter (GVSC) station, allowing the MTDC terminal to con...

  19. Single-point reactive power control method on voltage rise mitigation in residential networks with high PV penetration

    DEFF Research Database (Denmark)

    Hasheminamin, Maryam; Agelidis, Vassilios; Ahmadi, Abdollah

    2018-01-01

    Voltage rise (VR) due to reverse power flow is an important obstacle for high integration of Photovoltaic (PV) into residential networks. This paper introduces and elaborates a novel methodology of an index-based single-point-reactive power-control (SPRPC) methodology to mitigate voltage rise by ...... system with high r/x ratio. Efficacy, effectiveness and cost study of SPRPC is compared to droop control to evaluate its advantages....... by absorbing adequate reactive power from one selected point. The proposed index utilizes short circuit analysis to select the best point to apply this Volt/Var control method. SPRPC is supported technically and financially by distribution network operator that makes it cost effective, simple and efficient...

  20. Efficiency of the Compact Controlled High -Voltage Power Lines

    Directory of Open Access Journals (Sweden)

    Postolaty V.M.

    2015-12-01

    Full Text Available The basic theoretical principles to create compact controlled transmission lines are analyzed in the paper. The results of technical and project elaboration of some variants of such type of power transmission lines are presented and the comparison between their technical and economic indicators with those of traditional power transmission lines and foreign analogues is made in the paper. The efficiency of compact controlled transmission lines application to form power systems and to create intersystem ties as well as distribution electric network is also stated in the paper.

  1. General and Simple Decision Method for DG Penetration Level in View of Voltage Regulation at Distribution Substation Transformers

    Directory of Open Access Journals (Sweden)

    Joon-Ho Choi

    2013-09-01

    Full Text Available A distribution system was designed and operated by considering unidirectional power flow from a utility source to end-use loads. The large penetrations of distributed generation (DG into the existing distribution system causes a variety of technical problems, such as frequent tap changing problems of the on-load tap changer (OLTC transformer, local voltage rise, protection coordination, exceeding short-circuit capacity, and harmonic distortion. In view of voltage regulation, the intermittent fluctuation of the DG output power results in frequent tap changing operations of the OLTC transformer. Thus, many utilities limit the penetration level of DG and are eager to find the reasonable penetration limits of DG in the distribution system. To overcome this technical problem, utilities have developed a new voltage regulation method in the distribution system with a large DG penetration level. In this paper, the impact of DG on the OLTC operations controlled by the line drop compensation (LDC method is analyzed. In addition, a generalized determination methodology for the DG penetration limits in a distribution substation transformer is proposed. The proposed DG penetration limits could be adopted for a simplified interconnection process in DG interconnection guidelines.

  2. High-voltage pulse generator with inductive energy storage and thyratron

    CERN Document Server

    Vereshchagin, N M

    2002-01-01

    The high-voltage pulse generator with the energy storage on the basis of the single layer solenoid with inductivity of 10-35 mu H is described. The TGI2-500/20 thyratron able of breaking reliably the current with the amplitude of 800-850 A was used as the current breaker. The voltage on the load is formed in two stages. The first stage is characterized by the voltage of 20-25 kV and the growth time of 150-200 m. At the second stage there takes place fast (approx 60 ns) formation of the voltage up 90 kV. The scheme of the charge quenching decreases the instability of the current breaker time

  3. Low Voltage, High-Q SOI MEMS Varactors for RF Applications

    DEFF Research Database (Denmark)

    Yalcinkaya, Arda Deniz; Jensen, Søren; Hansen, Ole

    2003-01-01

    A micro electromechanical tunable capacitor with a low control voltage, a wide tuning range and high electrical quality factor is presented with detailed characterizations. A 50μm thick single-crystalline silicon layer was etched using deep reactive ion etching (DRIE) for obtaining high-aspect ra......A micro electromechanical tunable capacitor with a low control voltage, a wide tuning range and high electrical quality factor is presented with detailed characterizations. A 50μm thick single-crystalline silicon layer was etched using deep reactive ion etching (DRIE) for obtaining high...

  4. Overview of power converter designs feasible for high voltage transformer-less wind turbine

    DEFF Research Database (Denmark)

    Sztykiel, Michal

    2011-01-01

    Many leading wind turbine manufacturers are pushing forward in variable-speed wind turbines, often exceeding 5 MW. Therefore, novel designs and concepts for optimal high power wind turbines appeared. One of the most promising concepts is the high voltage (10-35 kV) transformer-less topology. High...... topology along with an overview of most promising candidates for optimal full-scale power converter design. Study is carried with proposed and justified high voltage wind turbine application along with selection of existing and most promising multilevel power converter topologies, which could...

  5. Multiloop Rapid-Rise/Rapid Fall High-Voltage Power Supply

    Science.gov (United States)

    Bearden, Douglas

    2007-01-01

    A proposed multiloop power supply would generate a potential as high as 1.25 kV with rise and fall times rise-time, and fall-time requirements. The power supply would include a preregulator that would be used to program a voltage 1/30 of the desired output voltage. By means of a circuit that would include a pulse-width modulator (PWM), two voltage doublers, and a transformer having two primary and two secondary windings, the preregulator output voltage would be amplified by a factor of 30. A resistor would limit the current by controlling a drive voltage applied to field-effect transistors (FETs) during turn-on of the PWM. Two feedback loops would be used to regulate the high output voltage. A pulse transformer would be used to turn on four FETs to short-circuit output capacitors when the outputs of the PWM were disabled. Application of a 0-to-5-V square to a PWM shut-down pin would cause a 20-to-1,250-V square wave to appear at the output.

  6. Design and power management of an offshore medium voltage DC microgrid realized through high voltage power electronics technologies and control

    Science.gov (United States)

    Grainger, Brandon Michael

    The growth in the electric power industry's portfolio of Direct Current (DC) based generation and loads have captured the attention of many leading research institutions. Opportunities for using DC based systems have been explored in electric ship design and have been a proven, reliable solution for transmitting bulk power onshore and offshore. To integrate many of the renewable resources into our existing AC grid, a number of power conversions through power electronics are required to condition the equipment for direct connection. Within the power conversion stages, there is always a requirement to convert to or from DC. The AC microgrid is a conceptual solution proposed for integrating various types of renewable generation resources. The fundamental microgrid requirements include the capability of operating in islanding mode and/or grid connected modes. The technical challenges associated with microgrids include (1) operation modes and transitions that comply with IEEE1547 without extensive custom engineering and (2) control architecture and communication. The Medium Voltage DC (MVDC) architecture, explored by the University of Pittsburgh, can be visualized as a special type of DC microgrid. This dissertation is multi-faceted, focused on many design aspects of an offshore DC microgrid. The focal points of the discussion are focused on optimized high power, high frequency magnetic material performance in electric machines, transformers, and DC/DC power converters---all components found within offshore, power system architectures. A new controller design based upon model reference control is proposed and shown to stabilize the electric motor drives (modeled as constant power loads), which serve as the largest power consuming entities in the microgrid. The design and simulation of a state-of-the-art multilevel converter for High Voltage DC (HVDC) is discussed and a component sensitivity analysis on fault current peaks is explored. A power management routine is

  7. High voltage plasma sheath analysis related to TSS-1

    Science.gov (United States)

    Sheldon, John W.

    1991-01-01

    On the first mission of the Tethered Satellite System (TSS-1), a 1.8 m diameter spherical satellite will be deployed a distance of 20 km above the space shuttle Orbiter on an insulated conducting tether. The satellite will be held at electric potentials up to 5000 volts positive with respect to the ambient plasma. Due to the passage of the conducting tether through the Earth's magnetic field, an emf will be created, driving electrons down the tether to the orbiter, out through an electron gun into the ionosphere and back into the positive biased satellite. Instrumentation on the satellite will measure electron flow to the surface at several locations, but these detectors have a limited range of acceptance angle. The problem addressed herein is the determination of the electron current distribution over the satellite surface and the angle of incidence of the incoming electrons relative to the surface normal.

  8. Analytical Model of Rain-Wind Induced Vibration of High-Voltage Transmission Line

    Directory of Open Access Journals (Sweden)

    Chao Zhou

    2014-10-01

    Full Text Available Under rainfall conditions, rain-wind induced vibration occurs on high-voltage transmission line occasionally. This phenomenon is caused by raindrops hitting the high-voltage conductor with a certain velocity and suspends to the bottom surface of the high-voltage conductor. By action of wind velocity and high-voltage conductor's motion, some suspended raindrops will be blown away or shaken off. The remaining water may be reformed as upper rivulet and lower rivulet. Like the effect of icing galloping, this type of vibration can cause metal fatigue on fittings and towers, while its mechanism remains unknown. The objective of this paper is to validate an analytical model of rain-wind induced vibration of the high-voltage transmission line and to investigate the effect of wind velocity, rivulet motion, raindrop velocity, and time varying mass on the vibration amplitude. Taking Tuo-chang transmission line as an example, the analytical model is solved by Galerkin weighted residual method and central difference method. The numerical results are in agreement with the experimental data available in the literature. The analytical model enables more comprehensive understanding of the rain-wind induced vibration mechanism.

  9. High Input Voltage Hall Thruster Discharge Converter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The overall scope of this Phase I/II effort is the development of a high efficiency 15kW (nominal) Hall thruster discharge converter. In Phase I, Busek Co. Inc. will...

  10. Power MOSFET Linearizer of a High-Voltage Power Amplifier for High-Frequency Pulse-Echo Instrumentation

    OpenAIRE

    Hojong Choi; Park Chul Woo; Jung-Yeol Yeom; Changhan Yoon

    2017-01-01

    A power MOSFET linearizer is proposed for a high-voltage power amplifier (HVPA) used in high-frequency pulse-echo instrumentation. The power MOSFET linearizer is composed of a DC bias-controlled series power MOSFET shunt with parallel inductors and capacitors. The proposed scheme is designed to improve the gain deviation characteristics of the HVPA at higher input powers. By controlling the MOSFET bias voltage in the linearizer, the gain reduction into the HVPA was compensated, thereby reduci...

  11. Benchmarking of Voltage Sag Generators

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede; Zou, Zhixiang

    2012-01-01

    to guide these grid-connected distributed power generation systems. In order to verify the response of such systems for voltage disturbance, mainly for evaluation of voltage sags/dips, a Voltage Sag Generator (VSG) is needed. This paper evaluates such sag test devices according to IEC 61000 in order...... to provide cheaper solutions to test against voltage sags. Simulation and experimental results demonstrate that the shunt impedance based VSG solution is the easiest and cheapest one for laboratory test applications. The back-to-back fully controlled converter based VSG is the most flexible solution......The increased penetration of renewable energy systems, like photovoltaic and wind power systems, rises the concern about the power quality and stability of the utility grid. Some regulations for Low Voltage Ride-Through (LVRT) for medium voltage or high voltage applications, are coming into force...

  12. Serially Connected Micro Amorphous Silicon Solar Cells for Compact High-Voltage Sources

    Directory of Open Access Journals (Sweden)

    Jiyoon Nam

    2016-01-01

    Full Text Available We demonstrate a compact amorphous silicon (a-Si solar module to be used as high-voltage power supply. In comparison with the organic solar module, the main advantages of the a-Si solar module are its compatibility with photolithography techniques and relatively high power conversion efficiency. The open circuit voltage of a-Si solar cells can be easily controlled by serially interconnecting a-Si solar cells. Moreover, the a-Si solar module can be easily patterned by photolithography in any desired shapes with high areal densities. Using the photolithographic technique, we fabricate a compact a-Si solar module with noticeable photovoltaic characteristics as compared with the reported values for high-voltage power supplies.

  13. Solid-Body Fuse Developed for High- Voltage Space Power Missions

    Science.gov (United States)

    Dolce, James L.; Baez, Anastacio N.

    2001-01-01

    AEM Incorporated has completed the development, under a NASA Glenn Research Center contract, of a solid-body fuse for high-voltage power systems of satellites and spacecraft systems. High-reliability fuses presently defined by MIL-PRF-23419 do not meet the increased voltage and amperage requirements for the next generation of spacecraft. Solid-body fuses exhibit electrical and mechanical attributes that enable these fuses to perform reliably in the vacuum and high-vibration and -shock environments typically present in spacecraft applications. The construction and screening techniques for solid-body fuses described by MIL-PRF-23419/12 offer an excellent roadmap for the development of high-voltage solid-body fuses.

  14. High power, medium voltage, series resonant converter for DC wind turbines

    DEFF Research Database (Denmark)

    Dincan, Catalin Gabriel; Kjær, Philip Carne; Chen, Yu-Hsing

    2017-01-01

    A new modulation scheme is introduced for a single-phase series-resonant converter, which permits continuous regulation of power from nominal level to zero, in presence of variable input and output dc voltage levels. Rearranging the circuit to locate the resonant LC tank on the rectifier side...... of the high turns-ratio transformer combined with frequency control and phase-shifted inverter modulation keep transformer flux constant from nominal frequency down to DC, always in sub-resonant continuous or discontinuous conduction mode. This overcomes the principal deficit of series-resonant converters......, and the resulting compact and efficient transformer, and soft-commutated inverter, present particular advantages in high-power, high-voltage applications, like DC offshore wind turbines. With transformer excitation frequency in hundreds of Hz range, line-frequency diodes can be employed in the high-voltage...

  15. The design, construction, and operation of long-distance high-voltage electricity transmission technologies.

    Energy Technology Data Exchange (ETDEWEB)

    Molburg, J. C.; Kavicky, J. A.; Picel, K. C.

    2008-03-03

    This report focuses on transmission lines, which operate at voltages of 115 kV and higher. Currently, the highest voltage lines comprising the North American power grid are at 765 kV. The grid is the network of transmission lines that interconnect most large power plants on the North American continent. One transmission line at this high voltage was built near Chicago as part of the interconnection for three large nuclear power plants southwest of the city. Lines at this voltage also serve markets in New York and New England, also very high demand regions. The large power transfers along the West Coast are generally at 230 or 500 kV. Just as there are practical limits to centralization of power production, there are practical limits to increasing line voltage. As voltage increases, the height of the supporting towers, the size of the insulators, the distance between conductors on a tower, and even the width of the right-of-way (ROW) required increase. These design features safely isolate the electric power, which has an increasing tendency to arc to ground as the voltage (or electrical potential) increases. In addition, very high voltages (345 kV and above) are subject to corona losses. These losses are a result of ionization of the atmosphere, and can amount to several megawatts of wasted power. Furthermore, they are a local nuisance to radio transmission and can produce a noticeable hum. Centralized power production has advantages of economies of scale and special resource availability (for instance, hydro resources), but centralized power requires long-distance transfers of power both to reach customers and to provide interconnections for reliability. Long distances are most economically served at high voltages, which require large-scale equipment and impose a substantial footprint on the corridors through which power passes. The most visible components of the transmission system are the conductors that provide paths for the power and the towers that keep these

  16. Controlled Operation of the Islanded Portion of the International Council on Large Electric Systems (CIGRE) Low Voltage Distribution Network

    DEFF Research Database (Denmark)

    Mustafa, Ghullam; Bak, Claus Leth; Ali, Ehsan

    2017-01-01

    is established by a VF controller. The voltage and the frequency of the islanded MG deviate when disconnected from the transmission grid and these deviations are caused by the load-generation imbalance. The voltage and the frequency of the islanded MG can be restored to the permissible limits if the desired......In islanding, a portion of the power network, comprised of the loads and distributed generation (DG) units, is isolated from the rest of the power grid and forms a micro grid (MG). In this condition, it becomes essential for the islanded MG to operate in a stable and controlled manner by providing...... ancillary services. When the MG is cut off from the main grid, the islanding must be detected by the DG units. In this condition it is essential that one of the controllers should be switched to the voltage-frequency (VF) control mode. In islanding, the network loses it slack reference and this reference...

  17. Charged residues distribution modulates selectivity of the open state of human isoforms of the voltage dependent anion-selective channel.

    Directory of Open Access Journals (Sweden)

    Giuseppe Federico Amodeo

    Full Text Available Voltage Dependent Anion-selective Channels (VDACs are pore-forming proteins located in the outer mitochondrial membrane. They are responsible for the access of ions and energetic metabolites into the inner membrane transport systems. Three VDAC isoforms exist in mammalian, but their specific role is unknown. In this work we have performed extensive (overall ∼5 µs Molecular Dynamics (MD simulations of the human VDAC isoforms to detect structural and conformational variations among them, possibly related to specific functional roles of these proteins. Secondary structure analysis of the N-terminal domain shows a high similarity among the three human isoforms of VDAC but with a different plasticity. In particular, the N-terminal domain of the hVDAC1 is characterized by a higher plasticity, with a ∼20% occurrence for the 'unstructured' conformation throughout the folded segment, while hVDAC2, containing a peculiar extension of 11 amino acids at the N-terminal end, presents an additional 310-helical folded portion comprising residues 10' to 3, adhering to the barrel wall. The N-terminal sequences of hVDAC isoforms are predicted to have a low flexibility, with possible consequences in the dynamics of the human VDACs. Clear differences were found between hVDAC1 and hVDAC3 against hVDAC2: a significantly modified dynamics with possible important consequence on the voltage-gating mechanism. Charge distribution inside and at the mouth of the pore is responsible for a different preferential localization of ions with opposite charge and provide a valuable rationale for hVDAC1 and hVDAC3 having a Cl-/K+ selectivity ratio of 1.8, whereas hVDAC2 of 1.4. Our conclusion is that hVDAC isoforms, despite sharing a similar scaffold, have modified working features and a biological work is now requested to give evidence to the described dissimilarities.

  18. Charged residues distribution modulates selectivity of the open state of human isoforms of the voltage dependent anion-selective channel.

    Science.gov (United States)

    Amodeo, Giuseppe Federico; Scorciapino, Mariano Andrea; Messina, Angela; De Pinto, Vito; Ceccarelli, Matteo

    2014-01-01

    Voltage Dependent Anion-selective Channels (VDACs) are pore-forming proteins located in the outer mitochondrial membrane. They are responsible for the access of ions and energetic metabolites into the inner membrane transport systems. Three VDAC isoforms exist in mammalian, but their specific role is unknown. In this work we have performed extensive (overall ∼5 µs) Molecular Dynamics (MD) simulations of the human VDAC isoforms to detect structural and conformational variations among them, possibly related to specific functional roles of these proteins. Secondary structure analysis of the N-terminal domain shows a high similarity among the three human isoforms of VDAC but with a different plasticity. In particular, the N-terminal domain of the hVDAC1 is characterized by a higher plasticity, with a ∼20% occurrence for the 'unstructured' conformation throughout the folded segment, while hVDAC2, containing a peculiar extension of 11 amino acids at the N-terminal end, presents an additional 310-helical folded portion comprising residues 10' to 3, adhering to the barrel wall. The N-terminal sequences of hVDAC isoforms are predicted to have a low flexibility, with possible consequences in the dynamics of the human VDACs. Clear differences were found between hVDAC1 and hVDAC3 against hVDAC2: a significantly modified dynamics with possible important consequence on the voltage-gating mechanism. Charge distribution inside and at the mouth of the pore is responsible for a different preferential localization of ions with opposite charge and provide a valuable rationale for hVDAC1 and hVDAC3 having a Cl-/K+ selectivity ratio of 1.8, whereas hVDAC2 of 1.4. Our conclusion is that hVDAC isoforms, despite sharing a similar scaffold, have modified working features and a biological work is now requested to give evidence to the described dissimilarities.

  19. An interleaved structure for a high-voltage planar transformer for a Travelling-wave Tube

    DEFF Research Database (Denmark)

    Zhao, Bin; Wang, Gang; Hurley, William G.

    2016-01-01

    is proposed to reduce leakage inductance and the insulation’s thickness is adjusted to optimize the electric isolation. In addition, the resistance and parasitic capacitance are investigated. With this method, a planar transformer used for a Travelling-Wave Tube Amplifier (TWTA) is designed. Calculations......Fully interleaved structure can significantly reduce leakage inductance in transformers, However, it is hard to apply them into high-voltage applications due to the electric insulation. In this paper, a partially interleaved structure that is suitable for high-voltage high frequency applications...

  20. Non-aqueous electrolyte for high voltage rechargeable magnesium batteries

    Science.gov (United States)

    Doe, Robert Ellis; Lane, George Hamilton; Jilek, Robert E; Hwang, Jaehee

    2015-02-10

    An electrolyte for use in electrochemical cells is provided. The properties of the electrolyte include high conductivity, high Coulombic efficiency, and an electrochemical window that can exceed 3.5 V vs. Mg/Mg.sup.+2. The use of the electrolyte promotes the electrochemical deposition and dissolution of Mg without the use of any Grignard reagents, other organometallic materials, tetraphenyl borate, or tetrachloroaluminate derived anions. Other Mg-containing electrolyte systems that are expected to be suitable for use in secondary batteries are also described.