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Sample records for ac transmission systems

  1. Flexible AC transmission systems modelling and control

    CERN Document Server

    Zhang, Xiao-Ping; Pal, Bikash

    2012-01-01

    The extended and revised second edition of this successful monograph presents advanced modeling, analysis and control techniques of Flexible AC Transmission Systems (FACTS). The book covers comprehensively a range of power-system control problems: from steady-state voltage and power flow control, to voltage and reactive power control, to voltage stability control, to small signal stability control using FACTS controllers. In the six years since the first edition of the book has been published research on the FACTS has continued to flourish while renewable energy has developed into a mature and

  2. Flexible AC transmission systems: the state of the art

    Energy Technology Data Exchange (ETDEWEB)

    Edris, Abdel-Aty [Electric Power Research Inst., Palo Alto, CA (United States). Electric Systems Division

    1994-12-31

    Flexible AC transmission systems (FACTS) is a concept promoting the use of power electronic controllers to enhance the controllability and usable capacity of AC transmission. This paper presents the state of the art of FACTS and the status of the current projects for the application of the FACTS controllers in transmission systems. (author) 8 refs., 8 figs.

  3. Development of the Field of Flexible AC Transmission Systems (FACTS)

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@ Theoretical and technological development of large capacity power electronics and flexible AC transmission systems are one of the most important projects developed by Tsinghua University. The Flexible AC Transmission System (FACTS) technology which uses power electronics to improve the efficiency and quality of the electrical generation, transmission and distribution system is considered to be one of the most significant technological innovations for power systems in the 20th century. The advanced static var generator (ASVG) is a key FACTS device.

  4. Guiding Principles in Selecting AC To DC Converters For Power Factor Corrections in AC Transmission System

    Directory of Open Access Journals (Sweden)

    Ibekwe B.E

    2014-10-01

    Full Text Available The ac to dc converters’ power factors correction in ac transmission system were investigated. The studies include: phase-controlled converter; pulse width modulated (PWM converter and ac input current shaped converter. Using Fourier series, power factors of these converters were calculated and simulated using MATLAB. The resulting curves are displayed in the hard copies for practical guides in the choice of converters; and comparatively, current shaped type is the best.

  5. High Voltage AC underground cable systems for power transmission

    DEFF Research Database (Denmark)

    Bak, Claus Leth; Silva, Filipe Miguel Faria da

    2016-01-01

    This paper is a second of two presenting a review of research results in underground cable transmission obtained by the Department of Energy Technology, Aalborg University ET/AAU and Danish TSO Energinet.dk within the last six years. The main core of the results are obtained by PhD students...... researching electrical engineering topics related to using underground cables for power transmission at EHV level and including the 420 kV level. The research topics were laid down by ET/AAU and Energinet.dk in the DANPAC (DANish Power systems with Ac Cables) research project. The main topics are discussed...

  6. High Voltage AC underground cable systems for power transmission

    DEFF Research Database (Denmark)

    Bak, Claus Leth; Silva, Filipe Miguel Faria da

    2016-01-01

    This paper is a first of two presenting a review of research results in underground cable transmission obtained by the Department of Energy Technology, Aalborg University ET/AAU and Danish TSO Energinet.dk within the last 6 years. The main core of the results are obtained by PhD students research......This paper is a first of two presenting a review of research results in underground cable transmission obtained by the Department of Energy Technology, Aalborg University ET/AAU and Danish TSO Energinet.dk within the last 6 years. The main core of the results are obtained by PhD students...... researching electrical engineering topics related to using underground cables for power transmission at EHV level and including the 420 kV level. The research topics were laid down by ET/AAU and Energinet.dk in the DANPAC (DANish Power systems with AC Cables) research project. The main topics are discussed...

  7. A Proposal on Low Frequency AC Transmission as a Multi-Terminal Transmission System

    Directory of Open Access Journals (Sweden)

    Achara Pichetjamroen

    2016-08-01

    Full Text Available This paper is focused on the discussion and comparison of characteristics and behavior of three low frequency ac (LFAC transmission system configurations operating under the same control scheme and conditions to identify the most promising operation system for LFAC. Merits of LFAC over high voltage direct current (HVDC are mentioned first. By changing power flow direction without auxiliary switches in multi-terminal application and easiness of short circuit protection are explained. The three configurations of LFACs are described and applied by the control scheme with the aid of the tool of the PSCAD/EMTDC software to consider the behavior of each LFAC system on line frequency and low frequency sides. For two-phase system, no fluctuation occurs on the line frequency side, which is the advantage over single-phase system. Furthermore, current rating on thyristor devices during operation and number of devices that used in each type of LFAC are calculated and compared. These results can lead to determine the most suitable transmission system for the LFAC system operation.

  8. DistFlow Extensions for AC Transmission Systems

    OpenAIRE

    Coffrin, Carleton; Hijazi, Hassan L.; Van Hentenryck, Pascal

    2015-01-01

    Convex relaxations of the power flow equations and, in particular, the Semi-Definite Programming (SDP), Second-Order Cone (SOC), and Convex DistFlow (CDF) relaxations, have attracted significant interest in recent years. Thus far, studies of the CDF model and its connection to the other relaxations have been limited to power distribution systems, which omit several parameters necessary for modeling transmission systems. To increase the applicability of the CDF relaxation, this paper develops ...

  9. Asymmetric operation of AC power transmission systems : the key to optimizing power system reliability and economics

    Energy Technology Data Exchange (ETDEWEB)

    Marceau, R.J. [University of Ontario Inst. of Technology, Oshawa, ON (Canada); McGillis, D.T. [McGill Univ., Montreal, PQ (Canada). Dept. of Electrical and Computer Engineering]|[Concordia Univ., Montreal, PQ (Canada). Dept. of Electrical and Computer Engineering; Sana, A.R.

    2006-07-01

    This book provides an invaluable tool for professionals working in the field of electrical engineering and applied science. It presents a simple and cost-effective strategy to operate alternating current (AC) power transmission systems more reliably and economically. Typically, bulk power transmission systems are operated symmetrically. When a problem such as a short-circuit occurs on a 3-phase line on an individual phase, all 3 phases are taken out of service. Such a strategy is fundamentally inefficient, given that most faults are single-line-to-ground faults. The more effective operating strategy presented in this book is based on the concept of asymmetric operation, which defines the operation of a 3-phase AC transmission line as 3 independently operated entities. As such, a 3-phase line can be operated with 1 or 2 phases out of service for single-line transmission corridors or with 1 , 2 or 3 phases out of service in the case of multiple-line corridors. This approach also maintains 3-phase symmetrical operation at its extremities, thereby protecting loads and power plants from undesirable voltages and currents. The overall integrity of 3-phase transmission is maintained in terms of power delivery, balanced voltages and currents even in the event of failures in part of the transmission system. The result is improved security. 67 refs., 42 tabs., 73 figs., 2 appendices.

  10. Scalable Heuristics for Planning, Placement and Sizing of Flexible AC Transmission System Devices

    Energy Technology Data Exchange (ETDEWEB)

    Frolov, Vladmir [Skolkovo Institute of Science and Technology, Skolkovo (Russia); Backhaus, Scott N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chertkov, Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-07-02

    Aiming to relieve transmission grid congestion and improve or extend feasibility domain of the operations, we build optimization heuristics, generalizing standard AC Optimal Power Flow (OPF), for placement and sizing of Flexible Alternating Current Transmission System (FACTS) devices of the Series Compensation (SC) and Static VAR Compensation (SVC) type. One use of these devices is in resolving the case when the AC OPF solution does not exist because of congestion. Another application is developing a long-term investment strategy for placement and sizing of the SC and SVC devices to reduce operational cost and improve power system operation. SC and SVC devices are represented by modification of the transmission line inductances and reactive power nodal corrections respectively. We find one placement and sizing of FACTs devices for multiple scenarios and optimal settings for each scenario simultaneously. Our solution of the nonlinear and nonconvex generalized AC-OPF consists of building a convergent sequence of convex optimizations containing only linear constraints and shows good computational scaling to larger systems. The approach is illustrated on single- and multi-scenario examples of the Matpower case-30 model.

  11. Mathematical model for the power supply system of an autonomous object with an AC power transmission over a cable rope

    Science.gov (United States)

    Rulevskiy, V. M.; Bukreev, V. G.; Shandarova, E. B.; Kuleshova, E. O.; Shandarov, S. M.; Vasilyeva, Yu Z.

    2017-02-01

    A modeling problem of the power system, which provides an AC power transmission to a submersible device over the conducting rope, was considered. The power supply system units and their parameters are described. The system multi-dimensional mathematical model in the variables state space with regard to the nonlinear characteristic of system elements is proposed.

  12. Enhancing power transfer capability through flexible AC transmission system devices:a review

    Institute of Scientific and Technical Information of China (English)

    Fadi M ALBATSH; Saad MEKHILEF; Shameem AHMAD; H MOKHLIS; M A HASSAN

    2015-01-01

    Global demand for power has significantly increased, but power generation and transmission capacities have not increased proportionally with this demand. As a result, power consumers suffer from various problems, such as voltage and frequency instability and power quality issues. To overcome these problems, the capacity for available power transfer of a transmission network should be enhanced. Researchers worldwide have addressed this issue by using flexible AC transmission system (FACTS) devices. We have conducted a comprehensive review of how FACTS controllers are used to enhance the avail-able transfer capability (ATC) and power transfer capability (PTC) of power system networks. This review includes a discussion of the classification of different FACTS devices according to different factors. The popularity and applications of these devices are discussed together with relevant statistics. The operating principles of six major FACTS devices and their application in increasing ATC and PTC are also presented. Finally, we evaluate the performance of FACTS devices in ATC and PTC im-provement with respect to different control algorithms.

  13. Stability Enhancement of Power System by Controlling Hvdc Power Flow through the Same Ac Transmission Line

    Directory of Open Access Journals (Sweden)

    P. Upendra Kumar

    2014-04-01

    Full Text Available Long extra high voltage (EHV ac lines cannot be loaded to their thermal limits in order to keep sufficient margin against transient instability. With the scheme proposed in this paper, it is possible to load these lines very close to their thermal limits. The conductors are allowed to carry usual ac along with dc superimposed on it. The added dc power flow does not cause any transient instability. This paper presents the feasibility of converting a double circuit ac line into composite ac–dc power transmission line to get the advantages of parallel ac–dc transmission to improve stability and damping out oscillations. Simulation and experimental studies are carried out for the coordinated control as well as independent control of ac and dc power transmissions. No alterations of conductors, insulator strings, and towers of the original line are needed. Substantial gain in the loadability of the line is obtained. Master current controller senses ac current and regulates the dc current orders for converters online such that conductor current never exceeds its thermal limit. The present paper is implemented by using MATLAB/SIMULINK.

  14. A novel power control strategy of Modular Multi-level Converter in HVDC-AC hybrid transmission systems for passive networks

    DEFF Research Database (Denmark)

    Hu, Zhenda; Wu, Rui; Yang, Xiaodong;

    2014-01-01

    With the development of High Voltage DC Transmission (HVDC) technology, there will be more and more HVDC-AC hybrid transmission system in the world. A basic challenge in HVDC-AC hybrid transmission systems is to optimize the power sharing between DC and AC lines, which become more severe when...... supplying power for passive networks, as the surplus power can only flow back to power grids through the AC lines. To deal with this issue, it demands not only accurate system capability design but also flexible power control strategy of power converters in VSC-HVDC. This paper proposes a novel power...

  15. The power supply system model of the process submersible device with AC power transmission over the cable-rope

    Science.gov (United States)

    Rulevskiy, V. M.; Bukreev, V. G.; Kuleshova, E. O.; Shandarova, E. B.; Shandarov, S. M.; Vasilyeva, Yu Z.

    2017-02-01

    A practical problem of power supply system modeling for the process submersible device with AC power transmission over the cable-rope was considered. The problem is highly relevant in developing and operation of submersible centrifugal pumps and submersibles. The results of modeling a symmetrical three-phase power supply system and their compliance with the real data are given at the paper. The obtained results in the mathematical and simulation models were similar.

  16. State of the art analysis of online fault location on AC cables in underground transmission systems

    DEFF Research Database (Denmark)

    Jensen, Christian Flytkjær; Gudmundsdottir, Unnur Stella; Bak, Claus Leth

    2011-01-01

    In this article the state of the art research for online fault location on cross-bonded transmission level cables is presented. The article is focused on the difficulties in using the algorithms developed for OHL-systems and distribution cables directly on cross-bonded transmission cables. Impeda...

  17. Online Location of Faults on AC Cables in Underground Transmission Systems

    DEFF Research Database (Denmark)

    Jensen, Christian Flytkjær

    parts; The preliminaries, a part which deals with the use of impedance-based fault location methods on crossbonded cables, a part which deals with travelling wave-based fault location, a part listing the conclusions and contributions of the thesis and an appendix. A state-of-the-art analysis......A transmission grid is normally laid out as an almost pure overhead line (OHL) network. The introduction of transmission voltage level XLPE cables and the increasing interest in the environmental impact of OHL has resulted in an increasing interest in the use of underground cables on transmission...... level. In Denmark for instance, the entire 150 kV, 132 kV and 220 kV and parts of the 400 kV transmission network will be placed underground before 2030. To reduce the operating losses of a cable-based transmission system, crossbonding schemes are normally used. The use of crossbonding introduces new...

  18. Ranking transmission projects in large scale systems using an AC power flow model; Priorizacao de obras em sistemas de grande porte usando um modelo AC da rede

    Energy Technology Data Exchange (ETDEWEB)

    Melo, A.C.G. [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil); Fontoura Filho, R.N. [ELETROBRAS, Rio de Janeiro, RJ (Brazil); Peres, L.A.P. Pecorelli [FURNAS, Rio de Janeiro, RJ (Brazil); Morozowski Filho, M. [Santa Catarina Univ., Florianopolis, SC (Brazil)

    1994-12-31

    Initially, this paper summarizes the approach developed by the Brazilian Planning Criteria Working Group (GTCP/ELETROBRAS) for identifying which subset of transmission investments should be postponed to meet a pre-stablished budget constraint with the least possible impact on system performance. Next, this paper presents the main features of the computational model PRIO, which allows the application of the ranking process to large scale power systems (2,000 buses and 3,000 circuits), with as many as 100 projects to be ranked. In this model, the adequacy analysis of each system state is carried out through an AC power flow coupled to a successive linear programming based remedial actions model. Case studies with the IEEE-RTS system and a configuration of the Brazilian Southeastern are presented and discussed. (author) 7 refs., 6 figs., 5 tabs.

  19. Enhancement of Power Quality in Transmission Line Using Flexible Ac Transmission System Device U.P.F.C (Unified Power Flow Controller

    Directory of Open Access Journals (Sweden)

    B. Divya Lakshmi

    2014-04-01

    Full Text Available Present scenario states that power demand has been increased in a rapid and random manner. Hence power generated is unable to meet the power demand so power scarcity exists. There is an approximate loss of (20 - 40 % of power generated during its transmission. Hence there is a need for enhancing the power quality in transmission lines. In order to improve the power quality our paper make use of FACTS DEVICES. FACTS devices can be added to power transmission and distribution systems at appropriate locations to improve system performance. The real and reactive powers can be easily controlled in a power system with FACTS devices. Flexible AC Transmission System creates a tremendous quality impact on power system stability. This paper describes the basic principle of operation of UPFC, its advantages and to compare its performance with the various FACTS equipment available. The objective of this paper is to keep the power system to remain in voltage stable condition when it experiences a load change and contingency, also deals with the simulation of various FACTS controllers using simulation program with MATLAB/SIMULINK

  20. 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).

  1. Application of Multi-Objective Evolutionary Algorithm for Optimal Reactive Power Dispatch with Flexible AC Transmission System Devices

    Directory of Open Access Journals (Sweden)

    Abdarrazak OUALI

    2011-12-01

    Full Text Available Because their capability to change the network parameters with a rapid response and enhanced flexibility, flexible AC transmission system (FACTS devices have taken more attention in power systems operations as improvement of voltage profile and minimizing system losses. In this way, this paper presents a multi-objective evolutionary algorithm (MOEA to solve optimal reactive power dispatch (ORPD problem with FACTS devices. This nonlinear multi-objective problem (MOP consists to minimize simultaneously real power loss in transmission lines and voltage deviation at load buses, by tuning parameters and searching the location of FACTS devices. The constraints of this MOP are divided to equality constraints represented by load flow equations and inequality constraints such as, generation reactive power sources and security limits at load buses. Two types of FACTS devices, static synchronous series compensator (SSSC and unified power flow controller (UPFC are considered. A comparative study regarding the effects of an SSSC and an UPFC on voltage deviation and total transmission real losses is carried out. The design problem is tested on a 6-bus system.

  2. Proposal of indexes for fast voltage stability evaluation of ac/dc transmission systems

    Directory of Open Access Journals (Sweden)

    Jorge Wilson González

    2011-01-01

    Full Text Available En este artículo se desarrolla un análisis de estabilidad de tensión de sistemas ca/cd empleando indicadores estáticos y modales. Se propone un tratamiento novedoso para indicadores de estabilidad de tensión, con el fin de obtener una mayor información sobre los requerimientos en redes de variadas fortalezas, en términos de la estabilidad de tensión. El nuevo tratamiento se ofrece como un medio para prevenir potenciales problemas en redes de transmisión de corriente directa, High Voltage dc Transmission Systems (HVdc, conectados a nodos débiles. Los indicadores son convertidos a por unidad y comparados en diferentes relaciones de corto circuito, Short Circuit Ratios (SCR, en una red modificada tipo IEEE de 14 barras, la cual posee un sistema HVdc conectado en su barra más débil. Los alcances pueden servir tanto para planeamiento como para monitoreo en tiempo real de la estabilidad de tensión en sistemas eléctricos de potencia incluyendo nodos ca/cd.

  3. Modelling of long High Voltage AC Cables in the Transmission System

    DEFF Research Database (Denmark)

    Gudmundsdottir, Unnur Stella

    , EMTDC/PSCAD is provided. A typical HV AC underground power cable is formed by 4 main layers, namely; Conductor-Insulation-Screen-Insulation. In addition to these main layers, the cable also has semiconductive screens, swelling tapes and metal foil. For high frequency modelling in EMT-based software...... and field measurement results. This is because of intersheath mode reflecting from the crossbonding points. The second main part of the work deals with improving the cable model based on the findings from analysis of the field measurements. The existing EMT-based models have the configuration for cables...

  4. ac transmission line field measurements

    Energy Technology Data Exchange (ETDEWEB)

    Kotter, F.R.; Misakian, M.

    1977-11-01

    The concern in recent years over the environmental effects of electric and magnetic fields from high voltage transmission lines has also focused attention on the accuracy of measurements of these fields. Electric field meters are discussed in terms of theory of operation, parameters affecting performance, meter performance under field and laboratory conditions, and calibration procedures. The performance and calibration of magnetic field meters is described. (LCL)

  5. Composite Based EHV AC Overhead Transmission Lines

    DEFF Research Database (Denmark)

    Sørensen, Thomas Kjærsgaard

    Overhead lines at transmission level are the backbone of any national power grid today. New overhead line projects however are at the same time subject to ever greater public resistance due to the lines environmental impact. As full undergrounding of transmission lines at extra high voltage (EHV...... and analysed with regard to the possibilities, limitations and risks widespread application of composite materials on EHV AC overhead transmission lines may present. To form the basis for evaluation of the useability of composite materials, dierent overhead line projects aimed at reducing the environmental...

  6. Online fault location on crossbonded AC cables in underground transmission systems

    DEFF Research Database (Denmark)

    F. Jensen, Christian; Bak, Claus Leth; Gudmundsdottir, Unnur Stella

    2014-01-01

    system are identified. The fault locator system uses the Wavelet Transform both to create reliable triggers in the units and to estimate the fault location based on time domain signals obtained in the substations by two fault locator units. Field measurements of faults artificially created on a section...

  7. Online Fault Location on AC Cables in Underground Transmission Systems using Sheath Currents

    DEFF Research Database (Denmark)

    Jensen, Christian Flytkjær; Nanayakkarab, Kasun; Rajapakse, Athula

    2014-01-01

    This paper studies online travelling wave methods for fault location on a crossbonded cable system using sheath currents. During the construction of the electrical connection to the 400 MW off shore wind farm Anholt, it was possible to perform measurements on a 38.4 km crossbonded cable system. A...

  8. Online fault location on AC cables in underground transmission systems using screen currents

    DEFF Research Database (Denmark)

    Jensen, Christian Flytkjær; Nanayakkara, O.M.K.K; Rajapakse, Athula

    This paper studies online travelling wave methods for fault location on a crossbonded cable system using screen currents. During the construction of the electrical connection to the 400 MW off shore wind farm Anholt, it was possible to perform measurements on a 38.4 km crossbonded cable system. A...

  9. Offshore windfarm connection with low frequency AC transmission technology

    DEFF Research Database (Denmark)

    Qin, Nan; Xu, Zhao; You, Shi

    2009-01-01

    This paper investigates the feasibility of using the low frequency AC transmission (LFAC) system, e.g. fraction of 50 Hz or 60 Hz, for connecting the large offshore wind farm to the grid by modelling and simulation. The LFAC system improves the transmission capacity and distance compared to the c...... to the reduced inductive reactance of the grid. Moreover, the harmonics introduced by the frequency converter may require extra filters to be installed in such system....

  10. Online fault location on AC cables in underground transmission systems using screen currents

    DEFF Research Database (Denmark)

    Jensen, Christian Flytkjær; Nanayakkara, O.M.K.K; Rajapakse, Athula

    This paper studies online travelling wave methods for fault location on a crossbonded cable system using screen currents. During the construction of the electrical connection to the 400 MW off shore wind farm Anholt, it was possible to perform measurements on a 38.4 km crossbonded cable system...... coils if the screen currents contain the necessary information for accurate fault location. In this paper, this is examined by analysis of field measurements and through a study of simulations. The wavelet transform and visual inspection methods are used and the accuracy is compared. Field measurements...... and simulations are compared for testing the reliability of using simulations for studying fault location methods....

  11. AC Losses of Prototype HTS Transmission Cables

    Energy Technology Data Exchange (ETDEWEB)

    Demko, J.A.; Dresner, L.; Hughey, R.L.; Lue, J.W.; Olsen, S.K.; Sinha, U.; Tolbert, J.C.

    1998-09-13

    Since 1995 Southwire Company and Oak Ridge National Laboratory (ORNL) have jointly designed, built, and tested nine, l-m long, high temperature superconducting (HTS) transmission cable prototypes. This paper summarizes the AC loss measurements of five of the cables not reported elsewhere, and compares the losses with each other and with theory developed by Dresner. Losses were measured with both a calorimetric and an electrical technique. Because of the broad resistive transition of the HTS tapes, the cables can be operated stably beyond their critical currents. The AC losses were measured in this region as well as below critical currents. Dresner's theory takes into account the broad resistive transition of the HTS tapes and calculates the AC losses both below and above the critical current. The two sets of AC 10SS data agree with each other and with the theory quite welL In particular, at low currents of incomplete penetration, the loss data agree with the theoretical prediction of hysteresis loss based on only the outer two Iayers carrying the total current.

  12. A Transient Fault Recognition Method for an AC-DC Hybrid Transmission System Based on MMC Information Fusion

    Directory of Open Access Journals (Sweden)

    Jikai Chen

    2016-12-01

    Full Text Available At present, the research is still in the primary stage in the process of fault disturbance energy transfer in the multilevel modular converter based high voltage direct current (HVDC-MMC. An urgent problem is how to extract and analyze the fault features hidden in MMC electrical information in further studies on the HVDC system. Aiming at the above, this article analyzes the influence of AC transient disturbance on electrical signals of MMC. At the same time, it is found that the energy distribution of electrical signals in MMC is different for different arms in the same frequency bands after the discrete wavelet packet transformation (DWPT. Renyi wavelet packet energy entropy (RWPEE and Renyi wavelet packet time entropy (RWPTE are proposed and applied to AC transient fault feature extraction from electrical signals in MMC. Using the feature extraction results of Renyi wavelet packet entropy (RWPE, a novel recognition method is put forward to recognize AC transient faults using the information fusion technology. Theoretical analysis and experimental results show that the proposed method is available to recognize transient AC faults.

  13. An adaptive neuro fuzzy inference system controlled space cector pulse width modulation based HVDC light transmission system under AC fault conditions

    Science.gov (United States)

    Ajay Kumar, M.; Srikanth, N.

    2014-03-01

    In HVDC Light transmission systems, converter control is one of the major fields of present day research works. In this paper, fuzzy logic controller is utilized for controlling both the converters of the space vector pulse width modulation (SVPWM) based HVDC Light transmission systems. Due to its complexity in the rule base formation, an intelligent controller known as adaptive neuro fuzzy inference system (ANFIS) controller is also introduced in this paper. The proposed ANFIS controller changes the PI gains automatically for different operating conditions. A hybrid learning method which combines and exploits the best features of both the back propagation algorithm and least square estimation method is used to train the 5-layer ANFIS controller. The performance of the proposed ANFIS controller is compared and validated with the fuzzy logic controller and also with the fixed gain conventional PI controller. The simulations are carried out in the MATLAB/SIMULINK environment. The results reveal that the proposed ANFIS controller is reducing power fluctuations at both the converters. It also improves the dynamic performance of the test power system effectively when tested for various ac fault conditions.

  14. Tevatron AC dipole system

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, R.; Kopp, S.E.; /Texas U.; Jansson, A.; Syphers, M.J.; /Fermilab

    2007-06-01

    The AC dipole is an oscillating dipole magnet which can induce large amplitude oscillations without the emittance growth and decoherence. These properties make it a good tool to measure optics of a hadron synchrotron. The vertical AC dipole for the Tevatron is powered by an inexpensive high power audio amplifier since its operating frequency is approximately 20 kHz. The magnet is incorporated into a parallel resonant system to maximize the current. The use of a vertical pinger magnet which has been installed in the Tevatron made the cost relatively inexpensive. Recently, the initial system was upgraded with a more powerful amplifier and oscillation amplitudes up to 2-3{sigma} were achieved with the 980 GeV proton beam. This paper discusses details of the Tevatron AC dipole system and also shows its test results.

  15. Identification of problems when using long high voltage AC cable in transmission system II: Resonance & Harmonic resonance

    DEFF Research Database (Denmark)

    Rahimi, Saeed; Wiechowski, W.; Randrup, M.;

    2008-01-01

    cable in transmission system. The objective of this paper and the companion paper is to address the most important problems expected in transmission system with relatively larger share of long HV underground cables. The end goal will be a guideline to special solutions and precautions to avoid dangerous...... over voltage problems and also resonance problems in a transmission network with future increased share of cables. Two major categories of problems are switching transient and resonance problems. In each category of the possible problems, first some theoretical background is provided...... and then the problem and countermeasures are discussed. In this paper most important resonance problems are addressed and discussed. Three main categories of resonance problems are: Near Resonance, Harmonic resonance and Ferroresonance....

  16. Cooling Floor AC Systems

    Science.gov (United States)

    Jun, Lu; Hao, Ding; Hong, Zhang; Ce, Gao Dian

    The present HVAC equipments for the residential buildings in the Hot-summer-and-Cold-winter climate region are still at a high energy consuming level. So that the high efficiency HVAC system is an urgently need for achieving the preset government energy saving goal. With its advantage of highly sanitary, highly comfortable and uniform of temperature field, the hot-water resource floor radiation heating system has been widely accepted. This paper has put forward a new way in air-conditioning, which combines the fresh-air supply unit and such floor radiation system for the dehumidification and cooling in summer or heating in winter. By analyze its advantages and limitations, we found that this so called Cooling/ Heating Floor AC System can improve the IAQ of residential building while keep high efficiency quality. We also recommend a methodology for the HVAC system designing, which will ensure the reduction of energy cost of users.

  17. Identification of problems when using long high voltage AC cable in transmission system I: Switching transient problems

    DEFF Research Database (Denmark)

    Rahimi, Saeed; Wiechowski, W.; Randrup, M

    2008-01-01

    Due to political and environmental pressures from the public and government side, upgrading and building new transmission facilities are becoming more and more difficult and in some cases the expansion of overhead transmission lines are impossible. This means that underground cable technology...

  18. A Secondary Voltage Control Method for an AC/DC Coupled Transmission System Based on Model Predictive Control

    DEFF Research Database (Denmark)

    Xu, Fengda; Guo, Qinglai; Sun, Hongbin;

    2015-01-01

    to keep the voltage of the pilot bus tracking its set point considering the DC system’s transmission schedule change. The approach is inspired by model predictive control (MPC) to compensate for predictable voltage change affected by DC side transmission power flow and the potential capacitor switching...

  19. A New and Accurate Fault Location Method in Three-Terminal Transmission Lines Compensated by Series-Connected Flexible AC Transmission System Devices

    Directory of Open Access Journals (Sweden)

    Haniyeh Marefatjou

    2013-09-01

    Full Text Available This paper proposes a new method to fault location in the three terminals transmission line compensated with series FACTS Devices. This method is based on the converting three line networks to two line networks after recognizing the faulty section and solving accessing the fault distance. So to solve the problem of fault location before determining distance to faulty section, new method to determine faulty section is proposed and then by converting three line networks to two line networks, the location of fault is determined using the proposed algorithm. In this method distributed transmission line model in time domain has been used which is another advantage of the proposed method compared to previous methods. This method for determining the faulty section used simultaneous voltage and current of all three terminals as input data. Due to problems in the modeling of FACTS devices during fault location, our proposed method does not used modeling series FACTS devices. Our proposed algorithm is not sensitive to the resistance of fault, the fault inception angle and fault type and do not dependent on compensator device location and its parameters. This method is good for all transmission lines compensated with any type of series compensator. Different types of fault in any different distance and situation simulated by using MATLAB/SIMULINK software on compensated three line network with Thyristor Control Series Capacitor(TCSC. The performance of the proposed algorithm is evaluated under different structural and fault conditions. The simulation results confirm the high accuracy of the proposed algorithm

  20. Fractional Frequency Transmission System and Its Applications

    Institute of Scientific and Technical Information of China (English)

    WANG Xifan; WANG Xiuli; TENG Yufei

    2012-01-01

    In 1994, we proposed transmission approach, the a novel fractional electricity frequency transmission system (FFTS), which uses lower frequency (50/3 Hz) to reduce the electrical length of AC power lines and thus obviously increases transmission capacity. The system is especially suitable to transmit remote renewable power such as hydro power and wind power.

  1. Optimal PowerFlow (OPF) Model with Unified AC-DC Load Flow and Optimal Commitmentfor an AC-catenary Railway Power Supply System (RPSS) fed by aHigh Voltage DC (HVDC) transmission line

    OpenAIRE

    Abrahamsson, Lars; Östlund, Stefan; Söder, Lennart

    2012-01-01

    In this paper an alternative railway power systems design based on an HVDC feeder is studied. The HVDC feeder is connected to the catenary by converters. Such an HVDC line is also appropriate for DC-fed railways and AC-fed railways working at public frequency. A unit commitment optimal power flow model has been developed and is applied on a test system. In this paper, the model is presented in detail. The model, in the form of an MINLP program, uses unified AC-DC power flow to minimize the en...

  2. A Research Review on the Transmission System of AC Servo Motor Direct Drive Hydraulic Press%交流伺服电机直驱液压机传动系统研究综述

    Institute of Scientific and Technical Information of China (English)

    范淑琴; 赵升吨; 陈超; 杨建辉

    2015-01-01

    交流伺服电机直驱液压机相比传统液压机,具有低速锻冲、快速空程向下及快速回程的特点,其交流伺服电机直驱的传动方式可有效减少滑块上行和下行的时间,大大提高液压机工作速度。介绍了国内外交流伺服电机直驱液压机传动系统的研究现状,提出了一种无油泵交流伺服电机直驱新型液压机传动方式,介绍了该新型液压机传动系统的构成及工作原理,并提出了研制该无油泵交流伺服电机直驱新型液压机所需要解决的科学问题。%Compared to the traditional hydraulic press, Ac servo motor direct drive hydraulic press has the characteris-tics including rapid falling, slow forging and fast return. The transmission mode of AC servo motor direct drive can effec-tively reduce both the falling time and rising time of the slider, and greatly improve the working speed of hydraulic press. The research status of transmission system of Ac servo motor direct drive hydraulic press are introduced in this paper, and the transmission model of a new type AC servo motor direct drive hydraulic press without oil pump is proposed. Both the composition and working principle of the transmission system of the new type hydraulic presser are introduced, and the sci-entific problems about the new type AC servo motor direct drive hydraulic press without oil pump are put forward.

  3. 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.

  4. Transmission Technologies and Operational Characteristic Analysis of Hybrid UHV AC/DC Power Grids in China

    Science.gov (United States)

    Tian, Zhang; Yanfeng, Gong

    2017-05-01

    In order to solve the contradiction between demand and distribution range of primary energy resource, Ultra High Voltage (UHV) power grids should be developed rapidly to meet development of energy bases and accessing of large-scale renewable energy. This paper reviewed the latest research processes of AC/DC transmission technologies, summarized the characteristics of AC/DC power grids, concluded that China’s power grids certainly enter a new period of large -scale hybrid UHV AC/DC power grids and characteristics of “strong DC and weak AC” becomes increasingly pro minent; possible problems in operation of AC/DC power grids was discussed, and interaction or effect between AC/DC power grids was made an intensive study of; according to above problems in operation of power grids, preliminary scheme is summarized as fo llows: strengthening backbone structures, enhancing AC/DC transmission technologies, promoting protection measures of clean energ y accessing grids, and taking actions to solve stability problems of voltage and frequency etc. It’s valuable for making hybrid UHV AC/DC power grids adapt to operating mode of large power grids, thus guaranteeing security and stability of power system.

  5. AC Loss of Ripple Current in Superconducting DC Power Transmission Cable

    Science.gov (United States)

    Yoshitomi, K.; Otabe, E. S.; Vyatkin, V. S.; Kiuchi, M.; Matsushita, T.; Hamabe, M.; Yamaguchi, S.; Inada, R.

    As a method of largely reducing the transmission loss in the electric power grid, superconducting direct current (DC) power transmission cable has been investigated. Using superconducting DC power transmission cables, large amounts of current and energy can be transferred compared to conventional copper cables. In this case, an alternating current (AC) is converted to DC and superposed AC which is known as ripple current, and the energy loss by the ripple current is generated. Therefore it is desired to estimate the energy loss density for the case of DC current and superposed AC current for a design of DC transmission cable system. In this study, the hysteresis loss for DC current of 2 kA rectified from 60 Hz alternating current is calculated using the Bean model, and coupling loss was also estimated. The diameter of the cable was 40 mm. The ripple currents generated by multi-pulse rectifiers, 6-pulse, 12-pulse, and 24-pulse were considered. It is found that the total AC loss including the hysteresis loss and the coupling loss is considerably smaller than the supposed heat loss of 0.5 W/m which is obtained with a newly developed cable.

  6. Digital model for harmonic interactions in AC/DC/AC systems

    Energy Technology Data Exchange (ETDEWEB)

    Guarini, A.P.; Rangel, R.D.; Pilotto, L.A.S.; Pinto, R.J.; Passos Junior, R. [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil)

    1994-12-31

    The main purpose of this paper is to present a model for calculation of HVdc converter harmonics taking into account the influence of the harmonic interactions between the ac systems in dc link transmissions. The ideas and methodologies used in the model development take into account the dc current ripple and ac voltage distortion in the ac systems. The theory of switching functions is applied to contemplate for the frequency conversions between the ac and dc sides, in an iterative process. It is possible then to obtain, even in balanced situations, non-characteristic harmonics that are produced by frequencies originated in the other terminal, which can be significant in a strongly coupled system, such as back-to-back configuration. (author) 9 refs., 3 figs.

  7. New Comparison of HVDC and HVAC Transmission system

    Directory of Open Access Journals (Sweden)

    Vahid Behravesh

    2012-06-01

    Full Text Available Alternating current (AC is the main driving force in the industries and residential areas, but for the long transmission line (more than 400 miles AC transmission is more expensive than that of direct current (DC. Technically, AC transmission line control is more complicated because of the frequency. DC transmission does not have these limitations, which has led to build long HVDC transmission lines over the last 40 years. HVDC technology made possible to transfer bulk power over long distances. This paper presents a comparative evaluation of HVDC and HVAC transmission systems .

  8. Magnetic Nanoparticle Thermometer: An Investigation of Minimum Error Transmission Path and AC Bias Error

    Directory of Open Access Journals (Sweden)

    Zhongzhou Du

    2015-04-01

    Full Text Available The signal transmission module of a magnetic nanoparticle thermometer (MNPT was established in this study to analyze the error sources introduced during the signal flow in the hardware system. The underlying error sources that significantly affected the precision of the MNPT were determined through mathematical modeling and simulation. A transfer module path with the minimum error in the hardware system was then proposed through the analysis of the variations of the system error caused by the significant error sources when the signal flew through the signal transmission module. In addition, a system parameter, named the signal-to-AC bias ratio (i.e., the ratio between the signal and AC bias, was identified as a direct determinant of the precision of the measured temperature. The temperature error was below 0.1 K when the signal-to-AC bias ratio was higher than 80 dB, and other system errors were not considered. The temperature error was below 0.1 K in the experiments with a commercial magnetic fluid (Sample SOR-10, Ocean Nanotechnology, Springdale, AR, USA when the hardware system of the MNPT was designed with the aforementioned method.

  9. Seventy Three SGCC Standards on 1000 kV UHV AC Transmission Technology

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Name of Project:73 Standards including Q/GDW 319-2009 1000kV AC Transmission System Overvoltage and Insulation Coordination Guidelines Main Participant Units:State Grid Corporation of China,China Electric Power Research Institute,State Grid Electric Power Research Institute,China Power Engineering Consulting Group Corporation,Communication and Construction Branch of State Grid Corporation,Grid Operation Branch of State Grid Corporation Main Contributors:Liu Zhenya,Shu Yinbiao,Zheng Baosen,Sun Xin,Chen Weijiang,Yu Yongqing,Wang Jianping,Sun Zhusen,Liang Xuming,Guo Jianbo Award Grade:First PrizeBackground Ultra-High Voltage (UHV) transmission is featured by long distance,large capacity,low line loss,and land conservation.Compared with 500 kV EHV transmission system,UHV transmission power can be 4-5 times for the same transmission distance,UHV transmission distance and corridor capacity can be 3 times,but loss of transmission lines can be only one third for the same transmission power.At the end of 2004,State Grid Corporation of China (SGCC) made a proposal to develop the UHV technology and build a strong power grid.

  10. DC Vs AC - War Of Currents For Future Power Systems A HVDC Technology Overview

    Directory of Open Access Journals (Sweden)

    Anil K. Rai

    2015-08-01

    Full Text Available DC vs AC discussion began in 1880s with development of first commercial power transmission in Wall Street New York. Later when AC technology came into notice by efforts of inventor and researcher Sir Nicola Tesla soon the advantages of AC transmission and AC devices overtook the DC technology. It was hoped that DC technology had lost battle of currents. Today with researches going on FACTS devices and bulk power transmission HVDC has again gained a reputation in power sector. Solution of this centuries old debate is to develop HVDC systems that assists HVAC systems for better performance stability and control

  11. Analysis on Phase Arrangement and Transposition Modes for UHV DC and Double-circuit EHV AC Transmission Line Built on the Same Tower

    Institute of Scientific and Technical Information of China (English)

    SIMA Wenxia; ZHOU Yuan; YUAN Tao; YANG Qing; SUN Shujie; Gilles Tremouille

    2012-01-01

    For AC and DC hybrid transmission lines, the arrangement and transposition modes of AC conductors not only affect the unbalance factor of AC lines, but also influence the bias current of DC converter transformers by AC and DC coupling. Excessive bias current will influence the normal operation of converter transformers, thus the optimal AC phase arrangement and transposition mode of hybrid lines was studied to minimize the coupling effect between AC and DC lines to fit the requirements on both aspects. Based on the parameters of the Ximeng-Shanghai project in China, a detailed simulation model of the DC converter station and the hybrid transmission line with double- circuit AC 500 kV transmission lines and DC ± 800 kV transmission lines were presented in the software PSCAD- EMTDC, and the coupling effects of the hybrid transmission lines were elucidated. The fundamental frequency components of DC poles with different operation conditions, arrangements of conductors and operation modes were analyzed, and the effective arrangement and transposition limiting the fundamental frequency current component of the DC line were compared. Simulation results show that AC operating conditions can affect DC induced components while the DC system operation mode has no apparent effect. With compact arrangement and inconsistent transposition of AC lines, the fundamental frequency component on DC lines can be reduced effectively; the three transposed mode within the hybrid line is the optimal layout scheme, considering both the requirements of DC bias current and AC unbalance degree.

  12. Adapting AC Lines to DC Grids for Large-Scale Renewable Power Transmission

    Directory of Open Access Journals (Sweden)

    D. Marene Larruskain

    2014-10-01

    Full Text Available All over the world, governments of different countries are nowadays promoting the use of clean energies in order to achieve sustainable energy systems. In this scenario, since the installed capacity is continuously increasing, renewable sources can play an important role. Notwithstanding that, some important problems may appear when connecting these sources to the grid, being the overload of distribution lines one of the most relevant. In fact, renewable generation is usually connected to the nearest AC grid, although this HV system may not have been designed considering distributed generation. In the particular case of large wind farms, the electrical grid has to transmit all the power generated by wind energy and, as a consequence, the AC system may get overloaded. It is therefore necessary to determine the impact of wind power transmission so that appropriate measures can be taken. Not only are these measures influenced by the amount of power transmitted, but also by the quality of the transmitted power, due to the output voltage fluctuation caused by the highly variable nature of wind. When designing a power grid, although AC systems are usually the most economical solution because of its highly proven technology, HVDC may arise in some cases (e.g. offshore wind farms as an interesting alternative, offering some added values such as lower losses and better controllability. This way, HVDC technology can solve most of the aforementioned problems and has a good potential for future use. Additionally, the fast development of power electronics based on new and powerful semiconductor devices allow the spread of innovative technologies, such as VSC-HVDC, which can be applied to create DC grids. This paper focuses on the main aspects involved in adapting the existing overhead AC lines to DC grids, with the objective of improving the transmission of distributed renewable energy to the centers of consumption.

  13. A novel wireless power and data transmission AC to DC converter for an implantable device.

    Science.gov (United States)

    Liu, Jhao-Yan; Tang, Kea-Tiong

    2013-01-01

    This article presents a novel AC to DC converter implemented by standard CMOS technology, applied for wireless power transmission. This circuit combines the functions of the rectifier and DC to DC converter, rather than using the rectifier to convert AC to DC and then supplying the required voltage with regulator as in the transitional method. This modification can reduce the power consumption and the area of the circuit. This circuit also transfers the loading condition back to the external circuit by the load shift keying(LSK), determining if the input power is not enough or excessive, which increases the efficiency of the total system. The AC to DC converter is fabricated with the TSMC 90nm CMOS process. The circuit area is 0.071mm(2). The circuit can produce a 1V DC voltage with maximum output current of 10mA from an AC input ranging from 1.5V to 2V, at 1MHz to 10MHz.

  14. Down hole transmission system

    Science.gov (United States)

    Hall, David R.; Hall, Jr., H. Tracy

    2007-07-24

    A transmission system in a downhole component comprises a data transmission element in both ends of the downhole component. Each data transmission element houses an electrically conducting coil in a MCEI circular trough. The electrically conducting coil comprises at least two generally fractional loops. In the preferred embodiment, the transmission elements are connected by an electrical conductor. Preferably, the electrical conductor is a coaxial cable. Preferably, the MCEI trough comprises ferrite. In the preferred embodiment, the fractional loops are connected by a connecting cable. In one aspect of the present invention, the connecting cable is a pair of twisted wires. In one embodiment the connecting cable is a shielded pair of twisted wires. In another aspect of the present invention, the connecting cable is a coaxial cable. The connecting cable may be disposed outside of the MCEI circular trough.

  15. Probabilistic transmission system planning

    CERN Document Server

    Li, Wenyuan

    2011-01-01

    "The book is composed of 12 chapters and three appendices, and can be divided into four parts. The first part includes Chapters 2 to 7, which discuss the concepts, models, methods and data in probabilistic transmission planning. The second part, Chapters 8 to 11, addresses four essential issues in probabilistic transmission planning applications using actual utility systems as examples. Chapter 12, as the third part, focuses on a special issue, i.e. how to deal with uncertainty of data in probabilistic transmission planning. The fourth part consists of three appendices, which provide the basic knowledge in mathematics for probabilistic planning. Please refer to the attached table of contents which is given in a very detailed manner"--

  16. NB Power Transmission system

    Energy Technology Data Exchange (ETDEWEB)

    Williamson, J. [NB Power Transmission, Fredericton, NB (Canada)

    2006-07-01

    The NB Power Transmission System operates 6700 km of transmission lines having voltages of 69 kV, 138 kV, 230 kV, and 345 kV. The history of lightning protection on this transmission system was presented. Lightning protection with shield wires has been applied selectively on the 69 kV and 138 kV lines and has been applied to all lines in the 230 kV and 345 kV range. Beginning in 2000, line arresters were installed on selected 69 kV and 138 kV lines. It was noted that although overhead shield wires are commonly installed to capture lightning strikes and shield the conductors, problems can occur if the electrical flashover of insulators result in a line to ground fault. Good grounding is needed to ensure that lightning enters the ground from the tower. The new approach is to install line arresters on structures without overhead shield wires. Line arresters are surge arresters applied in parallel with the insulator string. This new line arrester technology was tested by installing nearly 1200 arresters in the Saint John area. This paper described the reasons for choosing line arresters over shield wires and presented the methods of installation. The problems and failure rates of the installed line arresters were presented along with solutions, including solutions to protect lines against lightning in areas with heavy icing. Recommendations for future research into the use, application and development of line arresters were also presented. tabs., figs.

  17. Aswan HighDam/Cairo proposed HVDC transmission system

    Directory of Open Access Journals (Sweden)

    Ahmed Y.M.R. Salama

    2014-03-01

    The DC lines can carry more much power with two conductors than the power transmitted using an AC lines with three conductors of the same size. For the given power level, a DC line requires simpler and cheaper towers (From economical point of view, already installed towers for AC system can be used. Also reduced conductor sizes and insulator can be used. The power transmission losses also will be reduced to about two-thirds of the comparable AC system. The absence of skin effect with DC is also beneficial in reducing power losses marginally. Due to its fast controllability, HVDC transmission system has full control over transmitted power, an ability to enhance transient and dynamic stability in associated AC networks and can limit fault currents levels in the DC lines.

  18. Operation and control of a DC-grid offshore wind farm under DC transmission system faults

    DEFF Research Database (Denmark)

    Deng, Fujin; Chen, Zhe

    2013-01-01

    So far, all existing offshore wind farms have an ac collection system, and the collected power in the offshore wind farm is sent to an onshore ac grid through high-voltage ac (HVAC) or DC (HVDC) transmission lines. However, future of fshore wind farms may use dc also for power collection. Consequ...

  19. Security analysis of interconnected AC/DC systems

    DEFF Research Database (Denmark)

    Eriksson, Robert

    2015-01-01

    This paper analyses N-1 security in an interconnected ac/dc transmission system using power transfer distribution factors (PTDFs). In the case of a dc converter outage the power needs to be redistributed among the remaining converter to maintain power balance and operation of the dc grid. The red......This paper analyses N-1 security in an interconnected ac/dc transmission system using power transfer distribution factors (PTDFs). In the case of a dc converter outage the power needs to be redistributed among the remaining converter to maintain power balance and operation of the dc grid...... voltage control design consider the power distribution for a converter outage. By proper design and utilizing the proposed method increases the N-1 security and the secure transfer limits. This article proposes a method which minimizes the 2-norm of the sum of the PTDFs with constraints of not violating...... any line or transformer limits. Simulations were performed in a model of the Nordic power system where a dc grid is placed on top. The simulation supports the method as a tool to consider transfer limits in the grid to avoid violate the same and increase the security after a converter outage....

  20. AC Versus DC Link Comparison Based on Power Flow Analysis of a Multimachine Power System

    OpenAIRE

    Mohammed Abdeljalil DJEHAF; Sid Ahmed ZIDI; Youcef DJILANI KOBIBI

    2014-01-01

    Deregulation and privatization is posing new challenges on high voltage transmission and on distributions systems as well. An increasingly liberalized market will encourage trading opportunities to be identified and developed. High voltage power electronics, such as HVDC (High Voltage Direct Current) and FACTS (Flexible AC Transmission Systems) provide the necessary features to avoid technical problems in heavily loaded power systems; HVDC offers most advantages: it can be used for system int...

  1. Application Prospects of 1000-kV AC Transmission Technologies in China

    Institute of Scientific and Technical Information of China (English)

    Zhang Yunzhou; Jin Wen

    2007-01-01

    @@ The scale of 1000-kV AC transmission development, which relates to the strategy of the state's energy development, is mainly determined by the output scale of large pit-mouth power plants in northern China. The demonstration has shown the construction of large-sized pit-mouth power plants of air- cooling type in Shanxi, Shaanxi and Inner Mongolia for sending bulk power to Central and East China is economically rational and overall beneficial to environmental protection.

  2. Optical transmission versus ac magnetization measurements for monitoring colloidal Ni nanorod rotational dynamics

    Science.gov (United States)

    Gratz, M.; Tschöpe, A.

    2017-01-01

    Ni nanorods with an average length transmission of nanorod colloidal dispersions in alternating magnetic fields were measured and analyzed with the objective of comparing the intrinsic Brownian relaxation times obtained with the two methods. The different physical origin of the measured signal, related to different moments of the orientation distribution function, and the non-linear effects expected for the large magnetic moments of the Ni nanorods at common field amplitudes required a comprehensive modelling. The time-dependent magnetization and optical transmission in ac magnetic fields was derived by numerical solution of the Fokker-Planck equation. The simulated time-dependent magnetization and optical transmission at a given frequency and field amplitude were analyzed analogous to experimental data to determine characteristic relaxation frequencies. Empirical relationships were derived which enabled extraction of the intrinsic Brownian relaxation time from the characteristic frequencies measured in the non-linear regime. Despite large differences in the characteristic frequencies obtained from magnetization and optical transmission measurements, the retrieved intrinsic Brownian relaxation times were found to agree well. The potential of ac magnetic field-dependent optical transmission for biosensing applications was demonstrated by monitoring the adsorption of the protein gelatine on the nanorod labels.

  3. Hybrid-Vehicle Transmission System

    Science.gov (United States)

    Lupo, G.; Dotti, G.

    1985-01-01

    Continuously-variable transmission system for hybrid vehicles couples internal-combustion engine and electric motor section, either individually or in parallel, to power vehicle wheels during steering and braking.

  4. Hybrid-Vehicle Transmission System

    Science.gov (United States)

    Lupo, G.; Dotti, G.

    1985-01-01

    Continuously-variable transmission system for hybrid vehicles couples internal-combustion engine and electric motor section, either individually or in parallel, to power vehicle wheels during steering and braking.

  5. Experimental Investigation of the Corona Discharge in Electrical Transmission due to AC/DC Electric Fields

    Directory of Open Access Journals (Sweden)

    Fuangpian Phanupong

    2016-01-01

    Full Text Available Nowadays, using of High Voltage Direct Current (HVDC transmission to maximize the transmission efficiency, bulk power transmission, connection of renewable power source from wind farm to the grid is of prime concern for the utility. However, due to the high electric field stress from Direct Current (DC line, the corona discharge can easily be occurred at the conductor surface leading to transmission loss. Therefore, the polarity effect of DC lines on corona inception and breakdown voltage should be investigated. In this work, the effect of DC polarity and Alternating Current (AC field stress on corona inception voltage and corona discharge is investigated on various test objects, such as High Voltage (HV needle, needle at ground plane, internal defect, surface discharge, underground cable without cable termination, cable termination with simulated defect and bare overhead conductor. The corona discharge is measured by partial discharge measurement device with high-frequency current transformer. Finally, the relationship between supply voltage and discharge intensity on each DC polarity and AC field stress can be successfully determined.

  6. Corona noise model of high-voltage AC transmission lines and engineering applications

    Institute of Scientific and Technical Information of China (English)

    Wu Jiuhui; Di Zelong

    2013-01-01

    In order to predict the levels of corona noise from high-voltage alternating current (AC) transmission lines,the mechanism of corona noise and the corresponding theoretical prediction model are investigated.On the basis of Drude model,the motion of positive and negative ions produced by high-voltage corona is analyzed,and the mechanism of corona noise is discovered.The theoretical prediction model is put forward by using Kirchhoff formula,which is verified by the well agreement between our result and others',considering the case of three-phase single lines.Moreover,the calculation results show that for both single and bundled lines,the sound pressure level of the typical frequency,i.e.twice the power frequency,attenuates slowly and leads to an obviously interferential phenomenon near the transmission lines,but the level of the bundled lines is smaller than that of the single ones under the same transmission voltage.Based on the mechanism of corona noise and the prediction model,it is obvious that bundled lines and/or increased line radius can be adopted to reduce corona noise in the practical engineering applications effectively.This model can also provide a theoretical guidance for the high-volt-age AC transmission line design.

  7. Technical Papers for the Third Symposium on EHV AC Power Transmission. US-USSR Joint Committee on Cooperation in the Field of Energy.

    Energy Technology Data Exchange (ETDEWEB)

    Joint American-Soviet Committee on Cooperation in the Field of Energy.

    1982-05-10

    Eleven papers prepared for presentation at a symposium to be held during 1982 in the USA on scientific cooperation between the US and USSR in the field of research, design and operation of ehv/uhv ac and dc power transmission systems are included. A separate abstract was prepared for each paper. (LCL)

  8. Beamforming transmission in IEEE 802.11ac under time-varying channels.

    Science.gov (United States)

    Yu, Heejung; Kim, Taejoon

    2014-01-01

    The IEEE 802.11ac wireless local area network (WLAN) standard has adopted beamforming (BF) schemes to improve spectral efficiency and throughput with multiple antennas. To design the transmit beam, a channel sounding process to feedback channel state information (CSI) is required. Due to sounding overhead, throughput increases with the amount of transmit data under static channels. Under practical channel conditions with mobility, however, the mismatch between the transmit beam and the channel at transmission time causes performance loss when transmission duration after channel sounding is too long. When the fading rate, payload size, and operating signal-to-noise ratio are given, the optimal transmission duration (i.e., packet length) can be determined to maximize throughput. The relationship between packet length and throughput is also investigated for single-user and multiuser BF modes.

  9. Design of 1000-kV AC Single-Circuit Overhead Transmission Line

    Institute of Scientific and Technical Information of China (English)

    Li

    2010-01-01

    The UHVAC 1 000-kV transmission system is so far the one with the most advanced transmission technique applied and highest operation voltage. There are no guidelines or standards available for the design of 1 000-kV overhead transmission line in China. Study on key technologies and design schemes shall be carried out to ascertain the technical principles and construction standards for project construction, which are presented in this paper based on the Southeast Shanxi-Nanyang-Jingmen test and demonstration transmission line. A comparison and analysis of technical data and economic indices between UHV line and other lines are also described.

  10. Operating experience with factory-made air-insulated 1AC/2AC switchgear systems; Erste Betriebserfahrungen mit fabrikgefertigten, luftisolierten 1AC-/2AC-Schaltanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Northe, J. [Balfour Beatty Rail GmbH, Offenbach (Germany); Loenard, D. [Bombardier Transportation GmbH, Mannheim (Germany)

    2007-07-01

    Today, factory-made air-insulated switchgear systems of the type TracFeed {sup registered} are available for all supply versions of 16.7 Hz and 50 Hz a.c. railways. These are supported by auxiliary equipment to ensure reliable railway operation through specific protective functions and a simplified line test. (orig.)

  11. AC Versus DC Link Comparison Based on Power Flow Analysis of a Multimachine Power System

    Directory of Open Access Journals (Sweden)

    Mohammed Abdeljalil DJEHAF

    2014-02-01

    Full Text Available Deregulation and privatization is posing new challenges on high voltage transmission and on distributions systems as well. An increasingly liberalized market will encourage trading opportunities to be identified and developed. High voltage power electronics, such as HVDC (High Voltage Direct Current and FACTS (Flexible AC Transmission Systems provide the necessary features to avoid technical problems in heavily loaded power systems; HVDC offers most advantages: it can be used for system interconnection and for control of power flow as well. The major benefit of HVDC is its incorporated ability for fault-current blocking, which is not possible with synchronous AC links. In addition, HVDC can effectively support the surrounding AC systems in case of transient fault conditions and it serves as firewall against cascading disturbances. This paper presents a comparison between HVDC link and an HVAC link in a 29 Bus multimachine system, based on load flow analysis using Newton-Raphson method for the AC link case, and sequential method for the HVDC link case.

  12. Modeling and Simulation Analysis of Power Frequency Electric Field of UHV AC Transmission Line

    Directory of Open Access Journals (Sweden)

    Chen Han

    2015-02-01

    Full Text Available In order to study the power frequency electric field of UHV AC transmission lines, this paper which models and calculates using boundary element method simulates various factors influencing the distribution of the power frequency electric field, such as the conductor arrangement, the over-ground height, the split spacing and the sub conductor radius. Different influence of various factors on the electric field distribution will be presented. In a single loop, using VVV triangular arrangement is the most secure way; in a dual loop, the electric field intensity using reverse phase sequence is weaker than that using positive phase sequence. Elevating the over-ground height and reducing the conductor split spacing will both weaken the electric field intensity, while the change of sub conductor radius can hardly cause any difference. These conclusions are important for electric power company to detect circuit.

  13. Measurements of light transmission in deep sea with the AC9 trasmissometer

    CERN Document Server

    Capone, A; Grimaldi, A; Habel, R; Presti, D L; Migneco, E; Masullo, R; Moro, F; Petruccetti, M; Petta, C; Piattelli, P; Randazzo, N; Riccobene, G; Salusti, E; Sapienza, P; Sedita, M; Trasatti, L; Ursella, L; Capone, Antonio; Digaetano, Tullio; Grimaldi, Antonio; Habel, Roberto; Presti, Domenico Lo; Migneco, Emilio; Masullo, Rocco; Moro, Fulvio; Petruccetti, Marco; Petta, Catia; Piattelli, Paolo; Randazzo, Nunzio; Riccobene, Giorgio; Salusti, Ettore; Sapienza, Piera; Sedita, Mario; Trasatti, Luciano; Ursella, Laura

    2002-01-01

    The NEMO Collaboration aims to construct an underwater Cerenkov detector in the Mediterranean Sea, able to act as a neutrino telescope. One of the main tasks of this project, which implies difficult technological challenges, is the selection of an adequate marine site. In this framework the knowledge of light transmission properties in deep seawater is extremely important. The collaboration has measured optical properties in several marine sites near the Italian coasts, at depths >3000 m, using a set-up based on a AC9, a commercial trasmissometer, manufactured by WETLabs. The results obtained for the two sites reported in this paper Alicudi and Ustica, show that deep seawater optical properties are comparable to those of the clearest waters.

  14. TRANSMISSION OF DATA USING POWER LINE CARRIER COMMUNICATION SYSTEM

    Directory of Open Access Journals (Sweden)

    Jovita Serrao

    2012-11-01

    Full Text Available This paper serves as a general and technical reference to transmission of data using a power line carrier communication system which is a preferred choice over Wireless or other Home Networking technologies due to the ease of installation, availability of AC outlets, higher throughput, low cost, reliability and security. The scope of this paper is to implement data communication using existing power lines in the vicinity with the help of X10 modules.

  15. HVDC-AC system interaction from AC harmonics. Volume 1. Harmonic impedance calculations. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Breuer, G D; Chow, J H; Lindh, C B; Miller, N W; Numrich, F H; Price, W W; Turner, A E; Whitney, R R

    1982-09-01

    Improved methods are needed to characterize ac system harmonic behavior for ac filter design for HVDC systems. The purpose of this General Electric Company RP1138 research is to evaluate the present filter design practice and to investigate methods for calculating system harmonic impedances. An overview of ac filter design for HVDC systems and a survey of literature related to filter design have been performed. Two methods for calculating system harmonic impedances have been investigated. In the measurement method, an instrumentation system for measuring system voltage and current has been assembled. Different schemes of using the measurements to calculate system harmonic impedances have been studied. In the analytical method, a procedure to include various operating conditions has been proposed. Computer programs for both methods have been prepared, and the results of the measurement and analytical methods analyzed. A conclusion of the project is that the measurement and analytical methods both provided reasonable results. There are correlations between the measured and analytical results for most harmonics, although there are discrepancies between the assumptions used in the two methods. A sensitivity approach has been proposed to further correlate the results. From the results of the analysis, it is recommended that both methods should be tested further. For the measurement method, more testing should be done to cover different system operating conditions. In the analytical method, more detailed models for representing system components should be studied. In addition, alternative statistical and sensitivity approaches should be attempted.

  16. HVDC-AC system interaction from AC harmonics. Volume 1. Harmonic impedance calculations. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Breuer, G D; Chow, J H; Lindh, C B; Miller, N W; Numrich, F H; Price, W W; Turner, A E; Whitney, R R

    1982-09-01

    Improved methods are needed to characterize ac system harmonic behavior for ac filter design for HVDC systems. The purpose of this General Electric Company RP1138 research is to evaluate the present filter design practice and to investigate methods for calculating system harmonic impedances. An overview of ac filter design for HVDC systems and a survey of literature related to filter design have been performed. Two methods for calculating system harmonic impedances have been investigated. In the measurement method, an instrumentation system for measuring system voltage and current has been assembled. Different schemes of using the measurements to calculate system harmonic impedances have been studied. In the analytical method, a procedure to include various operating conditions has been proposed. Computer programs for both methods have been prepared, and the results of the measurement and analytical methods analyzed. A conclusion of the project is that the measurement and analytical methods both provided reasonable results. There are correlations between the measured and analytical results for most harmonics, although there are discrepancies between the assumptions used in the two methods. A sensitivity approach has been proposed to further correlate the results. From the results of the analysis, it is recommended that both methods should be tested further. For the measurement method, more testing should be done to cover different system operating conditions. In the analytical method, more detailed models for representing system components should be studied. In addition, alternative statistical and sensitivity approaches should be attempted.

  17. Electromagnetic Transient Analysis on Xinjiang 750 kV AC Transmission System%新疆750kV交流输电系统电磁暂态分析

    Institute of Scientific and Technical Information of China (English)

    刘青

    2011-01-01

    结合新疆地区乌北-吐鲁番-哈密750 kV输变电工程,研究了线路各种运行情况下的潜供电流、恢复电压,验证了高抗中性点小电抗取值的合理性.对于同杆架设双回路段,计算了正常运行线路对另一回检修线路的感应电压和感应电流.研究了各种运行方式下的工频过电压以及合闸操作过电压,同时分析了合闸空载变压器的过电压和励磁涌流.最后计算了光纤复合架空地线(optical power ground wire,OPGW)采用分段绝缘单点接地方式时的感应电压.电磁暂态程序(EMTP)的仿真计算表明,潜供电流、恢复电压数值不大,高抗中性点小电抗取值合适.同杆双回路接地刀闸电气参数符合要求.线路两端装设高抗后,工频过电压符合我国关于超高压线路工频过电压的要求.线路三相合闸、单相重合闸操作过电压不高,而且对金属氧化物避雷器(MOA)热容量要求不高.合闸空载变压器过电压和励磁涌流较小.OPGW感应电压不大,数值和分段长度基本成正比,采用分段绝缘单点接地方式利于减小线路电能损耗.%It is necessary to study the electromagnetic transients of 7 50 kV transmission line so as to provide reasonable reference for Insulation Coordination. Combined with Xinjiang 750 kV transmission system, the secondary arc current and the recovery voltage were studied. For the double circuit transmission line, the induction voltage and current were calculated. Moreover, the power frequency over-voltage and switching over-voltage, as well as the inrush currents and the over-voltages of closing no-load transformer, were studied. The induction voltage of optical fiber composite overhead ground wire (OPGW) was calculated, which was sectionally insulated and unilaterally grounded. The theoretical analysis and simulated results of Electro Magnetic Transient Program ( EMTP) show that the value of neutral reactance is selected suitably. The earth switch

  18. Transmission system planning in Ontario

    Energy Technology Data Exchange (ETDEWEB)

    Barrie, D.; Macedo, F.X.; Mcconnach, J.S. [Ontario Hydro, Toronto, ON (Canada)

    1994-12-31

    In recent years, new and modified approaches to planning the large transmission system that serves the province of Ontario, Canada, have been necessary to accommodate the rapidly changing planning environment including slower uncertain growth, ageing of facilities, integration of demand side management and non utility generation options, increased competitiveness, increased financial stresses and affordable constraints. This paper describes some of the new and modified approaches and tools that have been adopted or are being developed by Ontario Hydro to cope with this changing environment. (author) 9 refs., 4 figs.

  19. Wind-powered asynchronous AC/DC/AC converter system. [for electric power supply regulation

    Science.gov (United States)

    Reitan, D. K.

    1973-01-01

    Two asynchronous ac/dc/ac systems are modelled that utilize wind power to drive a variable or constant hertz alternator. The first system employs a high power 60-hertz inverter tie to the large backup supply of the power company to either supplement them from wind energy, storage, or from a combination of both at a preset desired current; rectifier and inverter are identical and operate in either mode depending on the silicon control rectifier firing angle. The second system employs the same rectification but from a 60-hertz alternator arrangement; it provides mainly dc output, some sinusoidal 60-hertz from the wind bus and some high harmonic content 60-hertz from an 800-watt inverter.

  20. VIDEO TRANSMISSION SYSTEM IN ITV APPLICATION

    Institute of Scientific and Technical Information of China (English)

    WangYancai; WangQunwei; WangZhaohui

    1996-01-01

    The transmission characteristics of video transmission mediums,coaxial cable and optical fiber ,are discussed in the paper. The formulas for frequency bandwidthare given to evaluate the video transmission distance. For typical video transmissionsystems with BB/IM and PFM/IM using optical fiber as the channel, expressions andcalculating results for both SIN and sensitivity are given. Finally. the principle for selecting different type of transmission systems according to transmission distances of the industrial TV is presented.

  1. AC propulsion system for an electric vehicle, phase 2

    Science.gov (United States)

    Slicker, J. M.

    1983-01-01

    A second-generation prototype ac propulsion system for a passenger electric vehicle was designed, fabricated, tested, installed in a modified Mercury Lynx vehicle and track tested at the Contractor's site. The system consisted of a Phase 2, 18.7 kw rated ac induction traction motor, a 192-volt, battery powered, pulse-width-modulated, transistorized inverter packaged for under rear seat installation, a 2-axis, 2-speed, automatically-shifted mechanical transaxle and a microprocessor-based powertrain/vehicle controller. A diagnostics computer to assist tuning and fault finding was fabricated. Dc-to-mechanical-system efficiency varied from 78% to 82% as axle speed/torque ranged from 159 rpm/788 nm to 65 rpm/328 nm. Track test efficiency results suggest that the ac system will be equal or superior to dc systems when driving urban cycles. Additional short-term work is being performed under a third contract phase (AC-3) to raise transaxle efficiency to predicted levels, and to improve starting and shifting characteristics. However, the long-term challenge to the system's viability remains inverter cost. A final report on the Phase 2 system, describing Phase 3 modifications, will be issued at the conclusion of AC-3.

  2. 49 CFR 191.13 - Distribution systems reporting transmission pipelines; transmission or gathering systems...

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Distribution systems reporting transmission pipelines; transmission or gathering systems reporting distribution pipelines. 191.13 Section 191.13... Distribution systems reporting transmission pipelines; transmission or gathering systems reporting...

  3. Reliability of emergency ac power systems at nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Battle, R E; Campbell, D J

    1983-07-01

    Reliability of emergency onsite ac power systems at nuclear power plants has been questioned within the Nuclear Regulatory Commission (NRC) because of the number of diesel generator failures reported by nuclear plant licensees and the reactor core damage that could result from diesel failure during an emergency. This report contains the results of a reliability analysis of the onsite ac power system, and it uses the results of a separate analysis of offsite power systems to calculate the expected frequency of station blackout. Included is a design and operating experience review. Eighteen plants representative of typical onsite ac power systems and ten generic designs were selected to be modeled by fault trees. Operating experience data were collected from the NRC files and from nuclear plant licensee responses to a questionnaire sent out for this project.

  4. Study of Power Flow Algorithm of AC/DC Distribution System including VSC-MTDC

    Directory of Open Access Journals (Sweden)

    Haifeng Liang

    2015-08-01

    Full Text Available In recent years, distributed generation and a large number of sensitive AC and DC loads have been connected to distribution networks, which introduce a series of challenges to distribution network operators (DNOs. In addition, the advantages of DC distribution networks, such as the energy conservation and emission reduction, mean that the voltage source converter based multi-terminal direct current (VSC-MTDC for AC/DC distribution systems demonstrates a great potential, hence drawing growing research interest. In this paper, considering losses of the reactor, the filter and the converter, a mathematical model of VSC-HVDC for the load flow analysis is derived. An AC/DC distribution network architecture has been built, based on which the differences in modified equations of the VSC-MTDC-based network under different control modes are analyzed. In addition, corresponding interface functions under five control modes are provided, and a back/forward iterative algorithm which is applied to power flow calculation of the AC/DC distribution system including VSC-MTDC is proposed. Finally, by calculating the power flow of the modified IEEE14 AC/DC distribution network, the efficiency and validity of the model and algorithm are evaluated. With various distributed generations connected to the network at appropriate locations, power flow results show that network losses and utilization of transmission networks are effectively reduced.

  5. Development of an AC Module System: Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Suparna Kadam; Miles Russell

    2012-06-15

    The GreenRay Inc. program focused on simplifying solar electricity and making it affordable and accessible to the mainstream population. This was accomplished by integrating a solar module, micro-inverter, mounting and monitoring into a reliable, 'plug and play' AC system for residential rooftops, offering the following advantages: (1) Reduced Cost: Reduction in installation labor with fewer components, faster mounting, faster wiring. (2) Maximized Energy Production: Each AC Module operates at its maximum, reducing overall losses from shading, mismatch, or module downtime. (3) Increased Safety. Electrical and fire safety experts agree that AC Modules have significant benefits, with no energized wiring or live connections during installation, maintenance or emergency conditions. (4) Simplified PV for a Broader Group of Installers. Dramatic simplification of design and installation of a solar power system, enabling faster and more efficient delivery of the product into the market through well-established, mainstream channels. This makes solar more accessible to the public. (5) Broadened the Rooftop Market: AC Modules enable solar for many homes that have shading, split roofs, or obstructions. In addition, due to the smaller building block size of 200W vs. 1000W, homeowners with budget limitations can start small and add to their systems over time. Through this DOE program GreenRay developed the all-in-one AC Module system with an integrated PV Module and microinverter, custom residential mounting and performance monitoring. Development efforts took the product from its initial concept, through prototypes, to a commercial product sold and deployed in the residential market. This pilot deployment has demonstrated the technical effectiveness of the AC Module system in meeting the needs and solving the problems of the residential market. While more expensive than the traditional central inverter systems at the pilot scale, the economics of AC Modules become

  6. Development of an AC Module System: Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Suparna Kadam; Miles Russell

    2012-06-15

    The GreenRay Inc. program focused on simplifying solar electricity and making it affordable and accessible to the mainstream population. This was accomplished by integrating a solar module, micro-inverter, mounting and monitoring into a reliable, 'plug and play' AC system for residential rooftops, offering the following advantages: (1) Reduced Cost: Reduction in installation labor with fewer components, faster mounting, faster wiring. (2) Maximized Energy Production: Each AC Module operates at its maximum, reducing overall losses from shading, mismatch, or module downtime. (3) Increased Safety. Electrical and fire safety experts agree that AC Modules have significant benefits, with no energized wiring or live connections during installation, maintenance or emergency conditions. (4) Simplified PV for a Broader Group of Installers. Dramatic simplification of design and installation of a solar power system, enabling faster and more efficient delivery of the product into the market through well-established, mainstream channels. This makes solar more accessible to the public. (5) Broadened the Rooftop Market: AC Modules enable solar for many homes that have shading, split roofs, or obstructions. In addition, due to the smaller building block size of 200W vs. 1000W, homeowners with budget limitations can start small and add to their systems over time. Through this DOE program GreenRay developed the all-in-one AC Module system with an integrated PV Module and microinverter, custom residential mounting and performance monitoring. Development efforts took the product from its initial concept, through prototypes, to a commercial product sold and deployed in the residential market. This pilot deployment has demonstrated the technical effectiveness of the AC Module system in meeting the needs and solving the problems of the residential market. While more expensive than the traditional central inverter systems at the pilot scale, the economics of AC Modules become

  7. Unified active and reactive power modulation of HVDC transmission systems

    Science.gov (United States)

    Grund, C. E.; Pohl, R. V.

    1981-11-01

    The power modulation of a high voltage direct current (HVDC) system for stabilization of an ac/dc network was investigated. It was found that simultaneous modulation of both dc current and voltage was more effective than just current modulation by itself, since the dc voltage modulation could be used to minimize the reactive power changes resulting from a change of the dc current. This helps stabilize the ac busbar voltages at the converters, which reduces undesirable load flow changes to voltage dependent ac loads, thus improving the effectiveness of the dc power modulation. This unified modulation control concept was evaluated by means of digital computer studies as well as a special purpose HVDC simulator. Several combined ac/dc power transmission systems were synthesized for testing of different modulation controller concepts. An optimum controller design incorporating a linear quadratic control algorithm with full state feedback was first studied. This provided a basis for comparison of suboptimal controller designs utilizing reduced state feedback and a Kalman filter state reconstruction technique.

  8. RESEARCH OF DYNAMIC CHARACTERIATIC FOR TRANSMISSION SYSTEM

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The kinetic precision of transmission chain is a key problem in the research of gear cutting machine transmission system.The traditional point of view is to consider the transmission chain as a geometrical meshing system,thus it is deemed that the kinetic precision of the transmission chain only depends on the manufacturing and assembly errors of its transmission parts.But further research reveals that the kinetic precision of transmission system is closely related with the system dynamic effects.Therefore,from the dynamic point of view,it is discerned that not only deems the transmission chain as a geometrical meshing system but also considers it as a dynamic system performing with torsional vibration.On the basis of analyses and processes of measuring data of samples from tests of cutting machine's kinetic precision of transmission chain,the results represent that the influences of dynamic characteristics of the transmission system on its kinetic precision is non-negligible.Experimental methods for discerning the transfer function of torsional vibration of gear transmission system and experimental results have been given.

  9. Coordinated Stability Control of Wind-Thermal Hybrid AC/DC Power System

    Directory of Open Access Journals (Sweden)

    Zhiqing Yao

    2015-01-01

    Full Text Available The wind-thermal hybrid power transmission will someday be the main form of transmitting wind power in China but such transmission mode is poor in system stability. In this paper, a coordinated stability control strategy is proposed to improve the system stability. Firstly, the mathematical model of doubly fed wind farms and DC power transmission system is established. The rapid power controllability of large-scale wind farms is discussed based on DFIG model and wide-field optical fiber delay feature. Secondly, low frequency oscillation and power-angle stability are analyzed and discussed under the hybrid transmission mode of a conventional power plant with wind farms. A coordinated control strategy for the wind-thermal hybrid AC/DC power system is proposed and an experimental prototype is made. Finally, real time simulation modeling is set up through Real Time Digital Simulator (RTDS, including wind power system and synchronous generator system and DC power transmission system. The experimental prototype is connected with RTDS for joint debugging. Joint debugging result shows that, under the coordinated control strategy, the experimental prototype is conductive to enhance the grid damping and effectively prevents the grid from occurring low frequency oscillation. It can also increase the transient power-angle stability of a power system.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-08-29

    A high-voltage direct-current (HVDC) transmission system includes an alternating current (AC) electrical source and a power converter channel that includes an AC-DC converter electrically coupled to the electrical source and a DC-AC inverter electrically coupled to the AC-DC converter. The AC-DC converter and the DC-AC inverter each include a plurality of legs that includes at least one switching device. The power converter channel further includes a commutating circuit communicatively coupled to one or more switching devices. The commutating circuit is configured to "switch on" one of the switching devices during a first portion of a cycle of the H-bridge switching circuits and "switch off" the switching device during a second portion of the cycle of the first and second H-bridge switching circuits.

  11. harmonics: generation and suppression in ac system networks

    African Journals Online (AJOL)

    2012-11-03

    Nov 3, 2012 ... HARMONICS: GENERATION AND SUPPRESSION IN AC. SYSTEM NETWORKS .... If Vs = 295V; Z = (8 + j6)Ω and δ = 2π/3, the output voltage, Vo and ... tor current assume the characteristics shown in figure. 8. The output ...

  12. Cryogenic System for a High Temperature Superconducting Power Transmission Cable

    Energy Technology Data Exchange (ETDEWEB)

    Demko, J.A.; Gouge, M.J.; Hughey, R.L.; Lue, J.W.; Martin, R.; Sinha, U.; Stovall, J.P.

    1999-07-12

    High-temperature superconducting (HTS) cable systems for power transmission are under development that will use pressurized liquid nitrogen to provide cooling of the cable and termination hardware. Southwire Company and Oak Ridge National Laboratory have been operating a prototype HTS cable system that contains many of the typical components needed for a commercial power transmission application. It is being used to conduct research in the development of components and systems for eventual commercial deployment. The cryogenic system was built by Air Products and Chemicals, Allentown, Pennsylvania, and can circulate up to 0.35 kg/s of liquid nitrogen at temperatures as low as 67 K at pressures of 1 to 10 bars. Sufficient cooling is provided for testing a 5-m-long HTS transmission cable system that includes the terminations required for room temperature electrical connections. Testing of the 5-m HTS transmission cable has been conducted at the design ac conditions of 1250 A and 7.5 kV line to ground. This paper contains a description of the essential features of the HTS cable cryogenic system and performance results obtained during operation of the system. The salient features of the operation that are important in large commercial HTS cable applications will be discussed.

  13. Theoretical analysis of AC electric field transmission into biological tissue through frozen saline for electroporation.

    Science.gov (United States)

    Xiao, Chunyan; Rubinsky, Boris

    2014-12-01

    An analytical model was used to explore the feasibility of sinusoidal electric field transmission across a frozen saline layer into biological tissue. The study is relevant to electroporation and permeabilization of the cell membrane by electric fields. The concept was analyzed for frequencies in the range of conventional electroporation frequencies and electric field intensity. Theoretical analysis for a variety of tissues show that the transmission of electroporation type electric fields through a layer of frozen saline into tissue is feasible and the behavior of this composite system depends on tissue type, frozen domain temperature, and frequency. Freezing could become a valuable method for adherence of electroporation electrodes to moving tissue surfaces, such as the heart in the treatment of atrial fibrillation or blood vessels for the treatment of restenosis.

  14. A Hybrid LCC-VSC HVDC Transmission System Supplying a Passive Load

    Science.gov (United States)

    Kotb, Omar

    High Voltage Direct Current (HVDC) transmission systems continue to be an excellent asset in modern power systems, mainly for their ability to overcome the problems of AC transmission, such as the interconnection of asynchronous grids, stability of long transmission lines, and use of long cables for power transmission. In the past 20 years, Voltage Source Converter (VSC)-HVDC transmission systems were developed and installed in many projects, thereby adding more operational benefits to DC transmission option, such as high controllability, ability to supply weak networks, and reduced converter reactive power demand. Nevertheless, VSC-HVDC transmission suffers from the disadvantages of high losses and cost. In this research, a hybrid HVDC employing a Line Commutated Converter (LCC) as rectifier and a VSC as inverter is used to supply a passive network through a DC cable. The hybrid system is best suited for unidirectional power transmission scenarios, such as power transmission to islands and remote load centers, where the construction of new transmission lines is prohibitively expensive. Control modes for the rectifier and inverter are selected and implemented using Proportional Integral (PI) controllers. Special control schemes are developed for abnormal operating conditions such as starting at light load and recovering from AC network faults. The system performance under steady state and transient conditions is investigated by EMTP-RV simulations. The results show the feasibility of the hybrid system.

  15. AC system stabilization via phase shift transformer with thyristor commutation

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Jose Carlos de; Guimaraes, Geraldo Caixeta; Moraes, Adelio Jose [Uberlandia Univ., MG (Brazil); Abreu, Jose Policarpo G. de [Escola Federal de Engenharia de Itajuba, MG (Brazil); Oliveira, Edimar Jose de [Juiz de Fora Univ., MG (Brazil)

    1994-12-31

    This article aims to present initially the constructive and operative forms of a phase-shift autotransformer which provides both magnitude and phase angle change through thyristor commutation, including a technic to reduce the number of thyristors. Following, it is proposed a control system to make such equipment an efficient AC system stabilizing tool. It is presented some simulation results to show the operation of this transformer in an electrical system. (author) 3 refs., 11 figs., 3 tabs.

  16. An Ac transposon system based on maize chromosome 4S for isolating long-distance-transposed Ac tags in the maize genome.

    Science.gov (United States)

    Wang, Fei; Li, Zhaoying; Fan, Jun; Li, Pengfei; Hu, Wei; Wang, Gang; Xu, Zhengkai; Song, Rentao

    2010-12-01

    Transposon tagging is an important tool for gene isolation and functional studies. In maize, several transposon-tagging systems have been developed, mostly using Activator/Dissociation (Ac/Ds) and Mutator systems. Here, we establish another Ac-based transposon system with the donor Ac tightly linked with sugary1 (su1) on maize chromosome 4S. Newly transposed Ac (tr-Acs) were detected based on a negative dosage effect, and long-distance-transposed Ac events were identified and isolated from the donor Ac by a simple backcross scheme. In this study, we identified 208 independent long-distance-transposed Ac lines. Thirty-one flanking sequences of these tr-Acs were isolated and localized in the maize genome. As found in previous studies, the tr-Acs preferentially inserted into genic sequences. The distribution of tr-Acs is not random. In our study, the tr-Acs preferentially transposed into chromosomes 1, 2, 9 and 10. We discuss the preferential distribution of tr-Acs from Ac systems. Our system is complementary to two other Ac-based regional-mutagenesis systems in maize, and the combined use of these systems will achieve an even and high-density distribution of Ac elements throughout the maize genome for functional-genomics studies.

  17. Control of the LHC 400 MHz RF System (ACS)

    CERN Document Server

    Arnaudon, L; Maesen, P; Prax, M

    2004-01-01

    The LHC ACS RF system is composed of 16 superconducting cavities, eight per ring. Each ring has two cryomodules, each containing four cavities. Each cavity is powered by a 300 kW klystron. The klystrons are grouped in fours, the klystrons in each group sharing a common 58 kV power converter and HV equipment bunker. The ACS RF control system is based on modern industrial programmable controllers (PLCs). A new fast interlock and alarm system with inbuilt diagnostics has been developed. Extensive use of the FIPIO Fieldbus drastically decreases the cabling complexity and brings improved signal quality, increased reliability and easier maintenance. Features of the implementation, such as system layout, communication and the high-level software interface are described. Operational facilities such as the automatic switch on procedure are described, as well as the necessary specialist tools and interfaces. A complete RF chain, including high voltage, cryomodule and klystron is presently being assembled in order to ch...

  18. Measuring System of Magnetostriction Under AC Excitation Using Optical Methods

    OpenAIRE

    Nakase, Tomoya; Nakano, Masanori; Fujiwara, F.; TAKAHASHI, N

    1998-01-01

    A measuring system for magnetostriction of silicon steel sheet using optical methods and a single sheet tester has been developed to establish a standard test method for IEC and JIS. Various factors affecting measurement accuracy and reproducibility of the developed system are examined. Two optical instruments, such as a laser Doppler vibrometer and a heterodyne displacement meter, are compared. 3-D characteristics of magnetostriction under ac excitation in the rolling direction are measured ...

  19. Design and Application of DC Deicer for AC Transmission System%交流输电系统直流融冰装置设计及其应用

    Institute of Scientific and Technical Information of China (English)

    傅闯; 许树楷; 饶宏; 黎小林; 陈亦平; 李立涅

    2013-01-01

    为了应对越来越频繁的冰灾,减少覆冰造成的电网设备破坏,避免大面积断线倒塔,进行了直流融冰装置的研发和应用.根据各电压等级架空线路直流融冰参数分析结果和人工气候试验室试验结论,提出了适用于我国电网交流输电线路的直流融冰技术方案.基于直流融冰关键参数研究结果,针对直流融冰的特殊性和变电站实际情况,提出了带专用整流变压器的12脉动直流融冰装置和不带专用整流变压器的6脉动直流融冰装置这2种经济实用的拓扑结构,完成了样机研发和现场试验.根据实际应用效果,进行了直流融冰装置的推广应用.2009-2012年覆冰期直流融冰装置在国内特别是南方电网的实际应用表明,这种直流融冰装置显著提高了电网抵御冰灾的能力.%In order to deal with ice damages and prevent towers and conductors in power grid from collapsing and being broken, it is necessary to develop DC deicer. Calculating and analyzing tests in an artificial climate chamber, and simulating the conductor deicing parameters, we proposed the DC deicing technical scheme for typical transmission lines at various voltage levels in China. According to the results of studying DC deicing key parameter, the particularity of deicing processes, and the practical situation of substations, we proposed two economical and practical topological structures of DC deicer, i. e, a 12-pulse DC deicer with a dedicated converter transformer and the other 6-pulse one without dedicated converter transformer. Moreover, prototypes of two types of de-icier were developed, and their field tests were performed. Based on the early application results, the deicers was popularized and applied in China, especially in China Southern Power Grid (CSG). The application during the icing seasons of 2009-2012 shows that the capacity of power gird withstanding ice calamity has been improved significantly by applying the DC deicing

  20. The minimization of ac phase noise in interferometric systems

    DEFF Research Database (Denmark)

    Filinski, Ignacy; Gordon, R A

    1994-01-01

    A simple step-by-step procedure, including several novel techniques discussed in the Appendices, is given for minimizing ac phase noise in typical interferometric systems such as two-beam interferometers, holographic setups, four-wave mixers, etc. Special attention is given to index of refraction...... fluctuations, direct mechanical coupling, and acoustic coupling, whose importance in determining ac phase noise in interferometric systems has not been adequately treated. The minimization procedure must be carried out while continuously monitoring the phase noise which can be done very simply by using...... with the optical table will also have to be carefully carried out regardless of the type of interferometric system employed.It is recommended that this be followed by a simple, inexpensive change to a novel type of interferometer discussed in Appendix A which is inherently less sensitive to mechanical vibration...

  1. Transport signatures in topological systems coupled to ac fields

    Science.gov (United States)

    Ruocco, Leonard; Gómez-León, Álvaro

    2017-02-01

    We study the transport properties of a topological system coupled to an ac electric field by means of Floquet-Keldysh formalism. We consider a semi-infinite chain of dimers coupled to a semi-infinite metallic lead and obtain the density of states and current when the system is out of equilibrium. Our formalism is nonperturbative and allows us to explore, in the thermodynamic limit, a wide range of regimes for the ac field, arbitrary values of the coupling strength to the metallic contact and corrections to the wide-band limit (WBL). We find that hybridization with the contact can change the dimerization phase, and that the current dependence on the field amplitude can be used to discriminate between them. We also show the appearance of side bands and nonequilibrium zero-energy modes, characteristic of the Floquet systems. Our results directly apply to the stability of nonequilibrium topological phases, when transport measurements are used for their detection.

  2. System and method for determining stator winding resistance in an AC motor using motor drives

    Science.gov (United States)

    Lu, Bin; Habetler, Thomas G; Zhang, Pinjia

    2013-02-26

    A system and method for determining the stator winding resistance of AC motors is provided. The system includes an AC motor drive having an input connectable to an AC source and an output connectable to an input terminal of an AC motor, a pulse width modulation (PWM) converter having switches therein to control current flow and terminal voltages in the AC motor, and a control system connected to the PWM converter. The control system generates a command signal to cause the PWM converter to control an output of the AC motor drive corresponding to an input to the AC motor, selectively generates a modified command signal to cause the PWM converter to inject a DC signal into the output of the AC motor drive, and determines a stator winding resistance of the AC motor based on the DC signal of at least one of the voltage and current.

  3. Gear Transmission Error Measurement System Made Operational

    Science.gov (United States)

    Oswald, Fred B.

    2002-01-01

    A system directly measuring the transmission error between the meshing spur or helical gears was installed at the NASA Glenn Research Center and made operational in August 2001. This system employs light beams directed by lenses and prisms through gratings mounted on the two gear shafts. The amount of light that passes through both gratings is directly proportional to the transmission error of the gears. The device is capable of resolution better than 0.1 mm (one thousandth the thickness of a human hair). The measured transmission error can be displayed in a "map" that shows how the transmission error varies with the gear rotation or it can be converted to spectra to show the components at the meshing frequencies. Accurate transmission error data will help researchers better understand the mechanisms that cause gear noise and vibration and will lead to The Design Unit at the University of Newcastle in England specifically designed the new system for NASA. It is the only device in the United States that can measure dynamic transmission error at high rotational speeds. The new system will be used to develop new techniques to reduce dynamic transmission error along with the resulting noise and vibration of aeronautical transmissions.

  4. Power Improvement of Transmission Line Using High Voltage Direct Current (Hvdc Transmission System

    Directory of Open Access Journals (Sweden)

    Lasisi, H

    2016-08-01

    Full Text Available The use of long EHV (Extremely High Voltage ac lines for the transmission of electrical energy increases the line reactance and susceptance which limits the thermal loadings on the line in order to keep sufficient margin against transient instability. With the scheme proposed in this paper, it is possible to load the lines very close to their limit with zero reactance and susceptance. The conductors are allowed to carry usual ac along with dc superimposed on it. The added dc power flow does not cause any transient instability. The scheme comprises a twelve-pulse bridge rectifier, dc-links, pulse width modulated (PSW-voltage sourced inverter (VSI and converter transformers. The master current controller is used to implement the scheme which senses ac current and regulates the dc current orders for converters online such that conductor current never exceeds its thermal limit. This paper gives the feasibility of converting a double circuit ac line into composite ac–dc power transmission line given the advantage of stability improvement, damping oscillations, voltage stabilization and reactive power compensation for ac weak buses. Simulation and experimental studies using MATLAB (Matrix Laboratory are carried out for the coordinated control as well as independent control of ac and dc power transmissions.

  5. 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.

  6. Methods, apparatus, and systems for monitoring transmission systems

    Energy Technology Data Exchange (ETDEWEB)

    Polk, Robert E; Svoboda, John M.; West, Phillip B.; Heath, Gail L.; Scott, Clark L.

    2016-07-19

    A sensing platform for monitoring a transmission system, and method therefor, may include a sensor that senses one or more conditions relating to a condition of the transmission system and/or the condition of an environment around the transmission system. A control system operatively associated with the sensor produces output data based on an output signal produced by the sensor. A transmitter operatively associated with the control system transmits the output data from the control system.

  7. Multi-core fiber undersea transmission systems

    DEFF Research Database (Denmark)

    Nooruzzaman, Md; Morioka, Toshio

    2017-01-01

    Various potential architectures of branching units for multi-core fiber undersea transmission systems are presented. It is also investigated how different architectures of branching unit influence the number of fibers and those of inline components.......Various potential architectures of branching units for multi-core fiber undersea transmission systems are presented. It is also investigated how different architectures of branching unit influence the number of fibers and those of inline components....

  8. Power Delivery in Multiterminal VSC-HVDC Transmission System for Offshore Wind Power Applications

    DEFF Research Database (Denmark)

    Silva, Rodrigo Da; Teodorescu, Remus; Rodriguez, Pedro

    2010-01-01

    This paper deals with one of the challenges in the field of offshore wind power systems: power transmission among the wind farms and the land when there is more than one AC grid to be considered. This case is known in the literature as multiterminal connection. The proposed studies are going to p...

  9. Interconnection of the power systems of the far east by using line HVDC transmission

    Directory of Open Access Journals (Sweden)

    Ilya Dydchenko

    2014-04-01

    Full Text Available The possibility of the interconnection continental part of the Russian Far East with the energy systems of Sakhalin and Japan. Indicate the technical possibility of this decision. The comparative analysis of the prospects for the construction of transmission lines of AC and DC. Proved the advantage of applying the lines of direct current for the interconnection of the Far East.

  10. Harmonics in transmission power systems

    DEFF Research Database (Denmark)

    Wiechowski, Wojciech Tomasz

    to perform more detailed harmonic studies emerged. Since the transmission network has a complex structure and its impedance varies with frequency in a nonlinear fashion, such harmonic study would require a detailed computer model of the network. Consequently, a PhD project proposal titled "Harmonics....... It is concluded that since some background harmonic distortion is practically always present in the network, a method based on variation of harmonic values must be used. The incremental values of harmonic distortion will allow to verify the harmonic model, despite the existence of background harmonic distortion...... GPS-synchronized OMICRON CMC256 units. Two such units are installed at 400 kV substations at both ends of the disconnected line and a third unit is located at a substation in a distance of 80 km. Time domain "snap-shot" measurements of three-phase voltages and currents are synchronously taken for some...

  11. APEnet+ 34 Gbps data transmission system and custom transmission logic

    Science.gov (United States)

    Ammendola, R.; Biagioni, A.; Frezza, O.; Lonardo, A.; Lo Cicero, F.; Paolucci, P. S.; Rossetti, D.; Simula, F.; Tosoratto, L.; Vicini, P.

    2013-12-01

    APEnet+ is a point-to-point, low-latency, 3D-torus network controller integrated in a PCIe Gen2 board based on the Altera Stratix IV FPGA. We characterize the transmission system (embedded transceivers driving external QSFP+ modules) analyzing signal integrity, throughput, latency, BER and jitter at different data rates up to 34 Gbps. We estimate the efficiency of a custom logic able to sustain 2.6 GB/s per link with an FPGA on-chip memory footprint of 40 KB, providing deadlock-free routing and systemic awareness of faults. Finally, we show the preliminary results obtained with the embedded transceivers of a next-generation FPGA and outline some ideas to increase the performance with the same FPGA memory footprint.

  12. ACS sampling system: design, implementation, and performance evaluation

    Science.gov (United States)

    Di Marcantonio, Paolo; Cirami, Roberto; Chiozzi, Gianluca

    2004-09-01

    By means of ACS (ALMA Common Software) framework we designed and implemented a sampling system which allows sampling of every Characteristic Component Property with a specific, user-defined, sustained frequency limited only by the hardware. Collected data are sent to various clients (one or more Java plotting widgets, a dedicated GUI or a COTS application) using the ACS/CORBA Notification Channel. The data transport is optimized: samples are cached locally and sent in packets with a lower and user-defined frequency to keep network load under control. Simultaneous sampling of the Properties of different Components is also possible. Together with the design and implementation issues we present the performance of the sampling system evaluated on two different platforms: on a VME based system using VxWorks RTOS (currently adopted by ALMA) and on a PC/104+ embedded platform using Red Hat 9 Linux operating system. The PC/104+ solution offers, as an alternative, a low cost PC compatible hardware environment with free and open operating system.

  13. System and Battery Charge Control for PV-Powered AC Lighting Systems

    Energy Technology Data Exchange (ETDEWEB)

    Kern, G.

    1999-04-01

    This report reviews a number of issues specific to stand-alone AC lighting systems. A review of AC lighting technology is presented, which discusses the advantages and disadvantages of various lamps. The best lamps for small lighting systems are compact fluorescent. The best lamps for intermediate-size systems are high- or low-pressure sodium. Specifications for battery charging and load control are provided with the goal of achieving lamp lifetimes on the order of 16,000 to 24,000 hours and battery lifetimes of 4 to 5 years. A rough estimate of the potential domestic and global markets for stand-alone AC lighting systems is presented. DC current injection tests were performed on high-pressure sodium lamps and the test results are presented. Finally, a prototype system was designed and a prototype system controller (with battery charger and DC/AC inverter) was developed and built.

  14. Nonlinear control of voltage source converters in AC-DC power system.

    Science.gov (United States)

    Dash, P K; Nayak, N

    2014-07-01

    This paper presents the design of a robust nonlinear controller for a parallel AC-DC power system using a Lyapunov function-based sliding mode control (LYPSMC) strategy. The inputs for the proposed control scheme are the DC voltage and reactive power errors at the converter station and the active and reactive power errors at the inverter station of the voltage-source converter-based high voltage direct current transmission (VSC-HVDC) link. The stability and robust tracking of the system parameters are ensured by applying the Lyapunov direct method. Also the gains of the sliding mode control (SMC) are made adaptive using the stability conditions of the Lyapunov function. The proposed control strategy offers invariant stability to a class of systems having modeling uncertainties due to parameter changes and exogenous inputs. Comprehensive computer simulations are carried out to verify the proposed control scheme under several system disturbances like changes in short-circuit ratio, converter parametric changes, and faults on the converter and inverter buses for single generating system connected to the power grid in a single machine infinite-bus AC-DC network and also for a 3-machine two-area power system. Furthermore, a second order super twisting sliding mode control scheme has been presented in this paper that provides a higher degree of nonlinearity than the LYPSMC and damps faster the converter and inverter voltage and power oscillations.

  15. Economics Of Optical Fibre Transmission Systems

    Science.gov (United States)

    Murray, W. J.

    1983-08-01

    Optical fibre as a telecommunication transmission medium has become one of the most significant developments so far of the digital era. A major contributory factor to the availability of optical fibre transmission systems has been the outstanding progress in the technology of manufacturing high quality glass fibre having relatively low attenuation and broad bandwidths. This and other achievements has enabled manufacturers in the United Kingdom to develop a range of optical fibre cables and transmission equipment for operation over short and long distances at the CCITT recommended digital hierarchical rates of 2, 8, 34 and 140Mbit/s which have been adopted by British Telecom (BT) for modernisation to an all digital transmission network. These optical fibre systems are now becoming increasingly price and performance competitive with conventional technology in many parts of telecommunications networks. In the British Telecom (BT) network the 140Mbit/s optical fibre systems are now economically competitive with equivalent systems on coaxial cable and microwave radio. The economics of 8 and 34Mbit/s systems are not yet sufficiently attractive, compared with 2Mbit/s digital line systems on pair type copper cables, for large scale use in rural and local distribution networks and are presently only justified on cost in and around large cities. As system costs decrease large applications are predicted particularly in support of future high speed data, cable television and visual information services.

  16. New Gear Transmission Error Measurement System Designed

    Science.gov (United States)

    Oswald, Fred B.

    2001-01-01

    The prime source of vibration and noise in a gear system is the transmission error between the meshing gears. Transmission error is caused by manufacturing inaccuracy, mounting errors, and elastic deflections under load. Gear designers often attempt to compensate for transmission error by modifying gear teeth. This is done traditionally by a rough "rule of thumb" or more recently under the guidance of an analytical code. In order for a designer to have confidence in a code, the code must be validated through experiment. NASA Glenn Research Center contracted with the Design Unit of the University of Newcastle in England for a system to measure the transmission error of spur and helical test gears in the NASA Gear Noise Rig. The new system measures transmission error optically by means of light beams directed by lenses and prisms through gratings mounted on the gear shafts. The amount of light that passes through both gratings is directly proportional to the transmission error of the gears. A photodetector circuit converts the light to an analog electrical signal. To increase accuracy and reduce "noise" due to transverse vibration, there are parallel light paths at the top and bottom of the gears. The two signals are subtracted via differential amplifiers in the electronics package. The output of the system is 40 mV/mm, giving a resolution in the time domain of better than 0.1 mm, and discrimination in the frequency domain of better than 0.01 mm. The new system will be used to validate gear analytical codes and to investigate mechanisms that produce vibration and noise in parallel axis gears.

  17. Investigation of potential driver modules and transmission lines for a high frequency power system on the space station

    Science.gov (United States)

    Brush, Harold T.

    1986-01-01

    The feasibility of using Series Resonant Inverter as the driver module for high frequency power system on the Space Station was assessed. The performance of the Series Resonant Inverter that was used in the testing of the single-phase, 2.0-kw resonant AC power system breadboard is summarized. The architecture is descirbed and the driver modules of the 5.0 kw AC power system breadboard are analyzed. An investigation of the various types of transmission lines is continued. Measurements of equivalent series resistor and inductor and equivalent parallel capacitors are presented. In particular, a simplified approach is utilized to describe the optimal transmission line.

  18. International Benchmarking of Electricity Transmission System Operators

    DEFF Research Database (Denmark)

    Agrell, Per J.; Bogetoft, Peter

    2014-01-01

    Electricity transmission system operators (TSO) in Europe are increasing subject to high-powered performance-based regulation, such as revenue-cap regimes. The determination of the parameters in such regimes is challenging for national regulatory authorities (NRA), since there is normally a single...

  19. Benchmarking European Gas Transmission System Operators

    DEFF Research Database (Denmark)

    Agrell, Per J.; Bogetoft, Peter; Trinkner, Urs

    This is the final report for the pan-European efficiency benchmarking of gas transmission system operations commissioned by the Netherlands Authority for Consumers and Markets (ACM), Den Haag, on behalf of the Council of European Energy Regulators (CEER) under the supervision of the authors....

  20. International Benchmarking of Electricity Transmission System Operators

    DEFF Research Database (Denmark)

    Agrell, Per J.; Bogetoft, Peter

    2014-01-01

    Electricity transmission system operators (TSO) in Europe are increasing subject to high-powered performance-based regulation, such as revenue-cap regimes. The determination of the parameters in such regimes is challenging for national regulatory authorities (NRA), since there is normally a single...

  1. Benchmarking European Gas Transmission System Operators

    DEFF Research Database (Denmark)

    Agrell, Per J.; Bogetoft, Peter; Trinkner, Urs

    This is the final report for the pan-European efficiency benchmarking of gas transmission system operations commissioned by the Netherlands Authority for Consumers and Markets (ACM), Den Haag, on behalf of the Council of European Energy Regulators (CEER) under the supervision of the authors....

  2. Point of collapse and continuation methods for large ac/dc systems

    Energy Technology Data Exchange (ETDEWEB)

    Canizares, C.A. (Escuela Politecnica Nacional, Quito (Ecuador)); Alvarado, F.L. (Univ. of Wisconsin, Madison, WI (United States))

    1993-02-01

    This paper describes the implementation of both Point of Collapse (PoC) methods and continuation methods for the computation of voltage collapse points (saddle-node bifurcations) in large ac/dc systems. A comparison of the performance of these methods is presented for real systems of up to 2,158 buses. The paper discusses computational details of the implementation of the PoC and continuation methods, and the unique challenges encountered due to the presence of high voltage direct current (HVDC) transmission, area interchange power control regulating transformers, and voltage and reactive power limits. The characteristics of a robust PoC power flow program are presented, and its application to detection and solution of voltage stability problems is demonstrated.

  3. Wireless Transmission System for Vehicle Inspection Data

    Institute of Scientific and Technical Information of China (English)

    LIU Yuan; MIAO Chang-yun

    2008-01-01

    Based on general packet radio service(GPRS) and TCP/IP protocol, a wireless transmission system of vehicle inspection data is designed. Basic structure and work theory are expounded. SIM300 designed by SIMCOM is used for client GPRS communication module. Using Winsock control of visual basic(VB), the client and server communication has been accomplished. By means of a client and server communications software, the remote wireless transmission of vehicle inspection data has been accomplished also. The server management software has been developed by using Microsoft SQL Server 2000 and VB6.0. Functions of software include import, inquiry, export and maintenance of test data.

  4. Power transmission cable development for the Space Station Freedom electrical power system

    Science.gov (United States)

    Schmitz, Gregory V.; Biess, John J.

    1989-01-01

    Power transmission cable is presently being evaluated under a NASA Lewis Research Center advanced development contract for application in the Space Station Freedom (SSF) electrical power system (EPS). Evaluation testing has been performed by TRW and NASA Lewis Research Center. The results of this development contract are presented. The primary cable design goals are to provide (1) a low characteristic inductance to minimize line voltage drop at 20 kHz, (2) electromagnetic compatibility control of the 20-kHz ac power current, (3) a physical configuration that minimizes ac resistance and (4) release of trapped air for corona-free operation.

  5. Thrust distribution for attitude control in a variable thrust propulsion system with four ACS nozzles

    Science.gov (United States)

    Lim, Yeerang; Lee, Wonsuk; Bang, Hyochoong; Lee, Hosung

    2017-04-01

    A thrust distribution approach is proposed in this paper for a variable thrust solid propulsion system with an attitude control system (ACS) that uses a reduced number of nozzles for a three-axis attitude maneuver. Although a conventional variable thrust solid propulsion system needs six ACS nozzles, this paper proposes a thrust system with four ACS nozzles to reduce the complexity and mass of the system. The performance of the new system was analyzed with numerical simulations, and the results show that the performance of the system with four ACS nozzles was similar to the original system while the mass of the whole system was simultaneously reduced. Moreover, a feasibility analysis was performed to determine whether a thrust system with three ACS nozzles is possible.

  6. Nonlinearity exponent of ac conductivity in disordered systems

    Science.gov (United States)

    Nandi, U. N.; Sircar, S.; Karmakar, A.; Giri, S.

    2012-07-01

    We measured the real part of ac conductance Σ(x,f) or Σ(T,f) of iron-doped mixed-valent polycrystalline manganite oxides LaMn1-xFexO3 as a function of frequency f by varying initial conductance Σ0 by quenched disorder x at a fixed temperature T (room) and by temperature T at a fixed quenched disorder x. At a fixed temperature T, Σ(x,f) of a sample with fixed x remains almost constant at its zero-frequency dc value Σ0 at lower frequency. With increase in f, Σ(x,f) increases slowly from Σ0 and finally increases rapidly following a power law with an exponent s at high frequency. Scaled appropriately, the data for Σ(T,f) and Σ(x,f) fall on the same universal curve, indicating the existence of a general scaling formalism for the ac conductivity in disordered systems. The characteristic frequency fc at which Σ(x,f) or Σ(T,f) increases for the first time from Σ0 scales with initial conductance Σ0 as {f}_{{c}}\\sim {\\Sigma }_{0}^{{x}_{f}}, where xf is the onset exponent. The value of xf is nearly equal to one and is found to be independent of x and T. Further, an inverse relationship between xf and s provides a self-consistency check of the systematic description of Σ(x,f) or Σ(T,f). This apparent universal value of xf is discussed within the framework of existing theoretical models and scaling theories. The relevance to other similar disordered systems is also highlighted.

  7. System and method for determining stator winding resistance in an AC motor

    Science.gov (United States)

    Lu, Bin; Habetler, Thomas G.; Zhang, Pinjia; Theisen, Peter J.

    2011-05-31

    A system and method for determining stator winding resistance in an AC motor is disclosed. The system includes a circuit having an input connectable to an AC source and an output connectable to an input terminal of an AC motor. The circuit includes at least one contactor and at least one switch to control current flow and terminal voltages in the AC motor. The system also includes a controller connected to the circuit and configured to modify a switching time of the at least one switch to create a DC component in an output of the system corresponding to an input to the AC motor and determine a stator winding resistance of the AC motor based on the injected DC component of the voltage and current.

  8. Transmission techniques for 4G systems

    CERN Document Server

    Da Silva, Mario Marques

    2012-01-01

    Fourth Generation (4G) wireless communication systems support current and emergent multimedia services such as mobile TV, social networks and gaming, high-definition TV, video teleconferencing, and messaging services. These systems feature the All-over-IP concept and boast improved quality of service. Several important R&D activities are currently under way in the field of wireless communications for 4G systems, but the coverage is widespread in the literature. Transmission Techniques for 4G Systems presents a compilation of the latest developments in the field of wireless communications for 4

  9. Engineering Calculation Method of Electromagnetic Effect on Oil/Gas Pipelines from 1 000 kV AC Transmission Line Having Single-phase Ground Fault

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wenliang; JIANG Jun; GUO Jian; LU Jiayu

    2012-01-01

    There will be more and more AC transmission lines near oil/gas pipelines in the future.So in order to determine the safe distance between them,simple and effective methods are required for engineers to efficiently evaluate the electromagnetic effect on oil/gas pipelines due to faults of AC transmission lines.In this paper,an easily handled fitting formula is obtained based on multiple calculation results,which is the maximum voltage on the pipeline anticorrosive coating produced by 1 000 kV AC transmission line under single phase ground fault.Although the calculation results obtained from the fitting formula differ from those gained by precise calculation with softwares,the verification of the formula shows that it is applicable for engineering calculation.This research could be applied to evaluate the electromagnetic effect of 1 000 kV AC transmission line under single-phase ground fault on nearby pipelines,as well as to determine the safe distance or the maximum parallel length.

  10. 多元组合ACS-TSP系统%A Multi-Metaheuristic Combined ACS-TSP System

    Institute of Scientific and Technical Information of China (English)

    陈芳

    2015-01-01

    文章提出了用多算法结合蚁族系统(ACS)求解旅行商问题(TSP)的方法,介绍了在ACS-TSP问题上的遗传算法,目的是为了寻找处理旅行商早期停滞现象的解空间.此外,还提出了一种新的最小生成树(MST)算法,结合最近邻(NN)来创建一个初始架构,以便又快又好地解决旅行商问题.%This paper presents a Multi-Metaheuristic combined Ant Colony System (ACS)-Travelling Salesman Problem (TSP) al-gorithm for solving the TSP. We introduce genetic algorithm in ACS-TSP to search solutions space for dealing with the early stagnation problem of the traveling salesman problem. Moreover, we present a new strategy of Minimum Spanning Tree(MST) coupled with Nearest Neighbor(NN) to construct a initial tour for improving TSP thus obtaining good solutions quickly. According to our simulation results, the new algorithm can provide a significant improvement for obtaining a global optimum solution or a near global optimum solution in large TSPs.

  11. 1000kV交流紧凑型输电关键技术研究%Key Technologies of 1000 kV AC Compact Transmission

    Institute of Scientific and Technical Information of China (English)

    胡毅; 万保权; 何慧雯

    2011-01-01

    2008年国网电力科学研究院开始进行特高压单回紧凑型输电关键技术的研究,在总结已取得的特高压输电技术科研成果的基础上,充分利用特高压交流试验基地(武汉)的良好科研条件,根据特高压紧凑型输电线路的特点,开展了多项有针对性的关键技术研究。为此,介绍了包括特高压紧凑型线路电磁环境及导线布置优化、外绝缘特性研究、过电压及绝缘配合、带电作业、金具研制及防舞动措施研究等方面所取得的一系列重要参数和研究结论。并且明确了特高压紧凑型输电关键技术的下一步研究工作重点,指出了需要在导线舞动相问安全间隙控制、进一步减小电晕噪声%The study on the key technologies of ultra high voltage ( UHV) compact transmission line has been started by State Grid Electric Power Research Institute (SGEPRI) scince 2008. By summarizing the previous work on key technologies of UHV transmission line and UHV AC Pilot Project and by fully utilizing the advanced test equipment in UHV AC test base in Wuhan, SGEPRI has researched a number of professional fields, such as electromagnetic environment and layout optimization of conductors, external insulation characteristic, overvoltage and insulation co- ordination, live working, fitting design and measures against galloping of transmission line. And some important pa- rameters and research conclusions have been achieved. According to the research conclusions, we presented the fo- cuses of further work, such as the control of security clearance between phases, reducing further the corona noise, live working, system stability and so on, and the UHV transmission project. technieal reserves for the subsequent compact construction of

  12. Analysis of Interline Power Flow Controller (IPFC Location in Power Transmission Systems

    Directory of Open Access Journals (Sweden)

    Amir Kahyaei

    2011-07-01

    Full Text Available The Interline Power Flow Controller (IPFC is one of the latest generation Flexible AC Transmission Systems (FACTS controller used to control power flows of multiple transmission lines. The aim of this paper is investigation of the effect of location of IPFC on profile of voltage and real and reactive power flow in transmission lines in power system. This model is incorporated in Newton- Raphson (NR power flow algorithm to study the power flow control in transmission lines in which IPFC is placed. A program in MATLAB/SIMULINK has been written in order to extend conventional NR algorithm based on this model. Numerical results are carried out on a standard power system. The results without and with IPFC for various locations are compared in terms of voltages, active and reactive power flows to demonstrate the performance of the IPFC model.

  13. System Frequency as Information Carrier in AC Power Systems

    DEFF Research Database (Denmark)

    Douglass, Philip James; Heussen, Kai; You, Shi

    2015-01-01

    Power generators contain control systems able to regulate system frequency, but the frequency setpoint values are only rarely modified from nominal values. This paper describes design considerations for a communication system from generators to frequency sensitive distributed energy resourc es (FS...... to carry information: First, a protocol for dispatching blocks of FS- DER that is suitable for systems restricted to relatively slow rates of change of frequency (ROCOF). Second, for systems that allow higher ROCOF values, the feasibility of using power generation resources as a power line communication......-DER) using changes to frequency setpoint values of genera- tors. Signaling discrete system states by generating off-nominal system frequency values can be used as a novel narrowband unidirectional broadcast communications channel. This paper describes two protocols for utilizing off-nominal frequencies...

  14. AC HTS Transmission Cable for Integration into the Future EHV Grid of the Netherlands

    Science.gov (United States)

    Zuijderduin, R.; Chevtchenko, O.; Smit, J. J.; Aanhaanen, G.; Melnik, I.; Geschiere, A.

    Due to increasing power demand, the electricity grid of the Netherlands is changing. The future grid must be capable to transmit all the connected power. Power generation will be more decentralized like for instance wind parks connected to the grid. Furthermore, future large scale production units are expected to be installed near coastal regions. This creates some potential grid issues, such as: large power amounts to be transmitted to consumers from west to east and grid stability. High temperature superconductors (HTS) can help solving these grid problems. Advantages to integrate HTS components at Extra High Voltage (EHV) and High Voltage (HV) levels are numerous: more power with less losses and less emissions, intrinsic fault current limiting capability, better control of power flow, reduced footprint, etc. Today's main obstacle is the relatively high price of HTS. Nevertheless, as the price goes down, initial market penetration for several HTS components is expected by year 2015 (e.g.: cables, fault current limiters). In this paper we present a design of intrinsically compensated EHV HTS cable for future grid integration. Discussed are the parameters of such cable providing an optimal power transmission in the future network.

  15. Adaptive Neurofuzzy Inference System-Based Pollution Severity Prediction of Polymeric Insulators in Power Transmission Lines

    OpenAIRE

    C. Muniraj; Chandrasekar, S

    2011-01-01

    This paper presents the prediction of pollution severity of the polymeric insulators used in power transmission lines using adaptive neurofuzzy inference system (ANFIS) model. In this work, laboratory-based pollution performance tests were carried out on 11 kV silicone rubber polymeric insulator under AC voltage at different pollution levels with sodium chloride as a contaminant. Leakage current was measured during the laboratory tests. Time domain and frequency domain characteristics of leak...

  16. Switching in electrical transmission and distribution systems

    CERN Document Server

    Smeets, René; Kapetanovic, Mirsad; Peelo, David F; Janssen, Anton

    2014-01-01

    Switching in Electrical Transmission and Distribution Systems presents the issues and technological solutions associated with switching in power systems, from medium to ultra-high voltage. The book systematically discusses the electrical aspects of switching, details the way load and fault currents are interrupted, the impact of fault currents, and compares switching equipment in particular circuit-breakers. The authors also explain all examples of practical switching phenomena by examining real measurements from switching tests. Other highlights include: up to date commentary on new develo

  17. An AC magnetohydrodynamic micropump: towards a true integrated microfluidic system

    Energy Technology Data Exchange (ETDEWEB)

    Lee, A P; Lemoff, A V; McConaghy, C F; Miles, R R

    1999-03-01

    An AC Magnetohydrodynamic (MHD) micropump has been demonstrated in which the Lorentz force is used to propel an electrolytic solution along a microchannel etched in silicon. This micropump has no moving parts, produces a continuous (not pulsatile) flow, and is compatible with solutions containing biological specimens. micropump, using the Lorentz force as the pumping mechanism for biological analysis. The AC Magnetohydrodynamic (MHD) micropump investigated produces a continuous flow and allows for complex microchannel design.

  18. Network video transmission system based on SOPC

    Science.gov (United States)

    Zhang, Zhengbing; Deng, Huiping; Xia, Zhenhua

    2008-03-01

    Video systems have been widely used in many fields such as conferences, public security, military affairs and medical treatment. With the rapid development of FPGA, SOPC has been paid great attentions in the area of image and video processing in recent years. A network video transmission system based on SOPC is proposed in this paper for the purpose of video acquisition, video encoding and network transmission. The hardware platform utilized to design the system is an SOPC board of model Altera's DE2, which includes an FPGA chip of model EP2C35F672C6, an Ethernet controller and a video I/O interface. An IP core, known as Nios II embedded processor, is used as the CPU of the system. In addition, a hardware module for format conversion of video data, and another module to realize Motion-JPEG have been designed with Verilog HDL. These two modules are attached to the Nios II processor as peripheral equipments through the Avalon bus. Simulation results show that these two modules work as expected. Uclinux including TCP/IP protocol as well as the driver of Ethernet controller is chosen as the embedded operating system and an application program scheme is proposed.

  19. Characterization of an Ac transposon system based on apt1-m1 (Ac) on the long arm of maize chromosome 9.

    Science.gov (United States)

    Wang, Fei; Li, Pengfei; Tang, Yuanping; Fan, Jun; Xu, Dabin; Guo, Shengming; Xu, Zhengkai; Song, Rentao

    2012-09-01

    Activator/Dissociation (Ac/Ds) transposable elements have been used in maize insertional mutagenesis as a complement to Mutator (Mu). In this study, to further improve the efficiency of the Ac/Ds mutagenesis system, we adopted apt1-m1 (Ac) on the long arm of chromosome 9 (9L) as a donor Ac to create an Ac insertion library. This system is based on the negative selection pressure against the donor Ac, and it was highly efficient for isolating new transposition events. We obtained 9,625 transposition events from 1083 F1 ears with an average transposition rate of 8.66 % (rates ranged from 1.11 to 29.73 %). We also adopted a modified PCR-based genome walking strategy to improve the efficiency of the new method for isolating transposon-flanking sequences. This method is more efficient than the Southern-based method that was used in previous studies. A validation step was developed to distinguish transposon tags derived from newly transposed Ac or Ds elements. Using this PCR-based method, we isolated 67 inheritable flanking sequences from the apt1-m1 (Ac) transposition library; of these, 51 were confirmed as tr-Ac-flanking sequences and 11 were tr-Ds-flanking sequences. Similar to other Ac donors from different loci, the apt1-m1 (Ac) system also exhibited a preference for short distance transposition. In this study, we have further improved the Ac mutagenesis system in maize for gene isolation and functional genomics studies.

  20. Highly Efficient Contactless Electrical Energy Transmission System

    Science.gov (United States)

    Ayano, Hideki; Nagase, Hiroshi; Inaba, Hiromi

    This paper proposes a new concept for a contactless electrical energy transmission system for an elevator and an automated guided vehicle. The system has rechargeable batteries on the car and electrical energy is supplied at a specific place. When electric power is supplied to the car, it runs automatically and approaches the battery charger. Therefore, a comparatively large gap is needed between the primary transformer at the battery charger and the secondary transformer on the car in order to prevent damage which would be caused by a collision. In this case, a drop of the transformer coupling rate due to the large gap must be prevented. In conventional contactless electrical energy transmission technology, since electric power is received by a pick-up coil from a power line, a large-sized transformer is required. And when the distance over which the car runs is long, the copper loss of the line also increases. The developed system adopts a high frequency inverter using a soft switching method to miniaturize the transformer. The system has a coupling rate of 0.88 for a transformer gap length of 10mm and can operate at 91% efficiency.

  1. 47 CFR 73.6023 - Distributed transmission systems.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Distributed transmission systems. 73.6023... distributed transmission system. ... RADIO BROADCAST SERVICES Class A Television Broadcast Stations § 73.6023 Distributed...

  2. International Benchmarking of Electricity Transmission System Operators

    DEFF Research Database (Denmark)

    Agrell, Per J.; Bogetoft, Peter

    2014-01-01

    Electricity transmission system operators (TSO) in Europe are increasing subject to high-powered performance-based regulation, such as revenue-cap regimes. The determination of the parameters in such regimes is challenging for national regulatory authorities (NRA), since there is normally a single...... TSO operating in each jurisdiction. The solution for European regulators has been found in international regulatory benchmarking, organized in collaboration with the Council of European Energy Regulators (CEER) in 2008 and 2012 for 22 and 23 TSOs, respectively. The frontier study provides static cost...... weight restrictions and a correction method for opening balances....

  3. EFFICIENT IMAGE TRANSMISSION SCHEME IN FMT SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Qi Zhongrui; Gao Zhenming

    2005-01-01

    An efficient image transmission scheme is proposed based on byte partition and adaptive sub-channel distribution technique in Filtered MultiTone (FMT) system over frequency selective slow fading channel. According to the simulation results and analysis of a typical image with matlab, improvement in Peak Signal to Noise Ratio (PSNR) of the received image and low complexity for equalization is demonstrated remarkably. Comparing with no adaptive and no actual channel equalization scheme, the proposed scheme saves over 6 dB when PSNR=40 dB.

  4. 47 CFR 73.1400 - Transmission system monitoring and control.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Transmission system monitoring and control. 73... be accomplished by either: (i) Direct supervision and control of transmission system parameters by a person at the transmitter site; or (ii) Remote control of the transmission system by a person at the main...

  5. 47 CFR 73.626 - DTV distributed transmission systems.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false DTV distributed transmission systems. 73.626... RADIO BROADCAST SERVICES Television Broadcast Stations § 73.626 DTV distributed transmission systems. (a... distributed transmission system (DTS). Except as expressly provided in this section, DTV stations operating...

  6. Instantaneous characteristics simulation and analysis on three-level brushless AC synchronous generators of aeronautic constant speed and frequency AC power system

    Science.gov (United States)

    Ma, Xiaohe; Shen, Songhua

    2006-11-01

    This paper mainly introduces theoretical analysis and experimental results of instantaneous characteristics on a certain three level brushless three-phase AC synchronous generators. The analysis, modeling and simulations with Simplorer software of Ansoft Company are carried out. It establishes three level generator models, gives theoretical relation matrix equation, and simulates some instantaneous characteristics. Design of the system requires reliable simulation tools with comprehensive component libraries capable of dealing with complex system behavior. The simulation results verify that the proposed system model can efficiently simulate the instantaneous characteristics of the real AC generator system. It gives better design experiences and digital methods for aeronautic constant speed and frequency AC power system.

  7. Using Imperialist Competitve Algorithm for Secured loadability enhancement with TCSC in transmission system for pool and hybrid model

    Directory of Open Access Journals (Sweden)

    Ehsan Afzalan

    2015-09-01

    Full Text Available This paper proposes an algorithm for the optimal location and control of Flexible AC Transmission System (FACTS devices for enhancing the loadability in transmission system using particle swarm optimization (PSO and Imperialist Competitve Algorithm (ICA for pool and hybrid model in deregulated electricity market. This approach uses AC load flow equations with the constraints on power generation, transmission line flow, magnitude of bus voltages and FACTS device settings. The bilateral transactions are modeled using secured bilateral transaction matrix utilizing AC distribution factor with the slack bus contribution. In this proposed approach, Thyristor Controlled Series Compensator (TCSC is used. To validate the proposed approach, simulations are performed on 39-bus New England test system and IEEE 118-bus system. Comparisons are made in terms of maximum loadability, computation time. The simulation results obtained indicate that by optimal location and control of TCSC, using ICA, the loadability in transmission system is enhanced and a less computation time is achieved. The comparative study concludes that by the optimal location and control of TCSC using ICA method the secured loadability enhancement is obtained in the transmission system in deregulated electricity market.

  8. Energy analysis of the basic materials utilized in electric power transmission systems

    Energy Technology Data Exchange (ETDEWEB)

    1979-04-30

    The energy content per mile of installed underground and overhead power transmission systems has been calculated for the following types of systems: self-contained oil-filled cables; HPOF pipe-type cables; extruded dielectric cables; compressed-gas-insulated systems; overhead lines (ac and dc) and two proposed superconducting systems (ac and dc). The system operating voltages analyzed included 138, 230, 345, 500, 765 and 1,200 kV for ac systems, but all systems were not analyzed at the higher voltages. The dc overhead lines operated at +-200, +-400, +-600 and +-800 kV. Total installed energy content for these systems ranged from 4 x 10/sup 9/ to 1.2 x 10/sup 11/ Btu per mile. Installation energy requirements were generally 10% or less of the inherent system energy content based on the materials used in each system. Most of the energy content in each system can be attributed to the metallic components; plastic and insulating oil also contribute significantly. The energy content of 36 materials and basic products, in terms of Btu per ton, was calculated as part of this study. Substitution of conductor materials (e.g., aluminum for copper) in cable systems resulted in changes in the total system energy content on the order of 15%.

  9. Ac-dc Bus-interface Bi-directional Converters in Renewable Energy Systems

    OpenAIRE

    Dong, Dong

    2012-01-01

    This dissertation covers several issues related to the ac-dc bus-interface bi-directional converters in renewable energy systems. The dissertation explores a dc-electronic distribution system for residential and commercial applications with a focus on the design of an ac-dc bi-directional converter for such application. This converter is named as the â Energy Control Centerâ due to its unique role in the system. First, the impact of the unbalanced power from the ac grid, especially the ...

  10. Multi-transmission-line-beam interactive system

    Energy Technology Data Exchange (ETDEWEB)

    Figotin, Alexander; Reyes, Guillermo [Department of Mathematics, University of California at Irvine, Irvine, California 92697-3875 (United States)

    2013-11-15

    We construct here a Lagrangian field formulation for a system consisting of an electron beam interacting with a slow-wave structure modeled by a possibly non-uniform multiple transmission line (MTL). In the case of a single line we recover the linear model of a traveling wave tube due to J. R. Pierce. Since a properly chosen MTL can approximate a real waveguide structure with any desired accuracy, the proposed model can be used in particular for design optimization. Furthermore, the Lagrangian formulation provides: (i) a clear identification of the mathematical source of amplification, (ii) exact expressions for the conserved energy and its flux distributions obtained from the Noether theorem. In the case of uniform MTLs we carry out an exhaustive analysis of eigenmodes and find sharp conditions on the parameters of the system to provide for amplifying regimes.

  11. Combined heuristic with fuzzy system to transmission system expansion planning

    Energy Technology Data Exchange (ETDEWEB)

    Silva Sousa, Aldir; Asada, Eduardo N. [University of Sao Paulo, Sao Carlos School of Engineering, Department of Electrical Engineering Av. Trabalhador Sao-carlense, 400, 13566-590 Sao Carlos, SP (Brazil)

    2011-01-15

    A heuristic algorithm that employs fuzzy logic is proposed to the power system transmission expansion planning problem. The algorithm is based on the divide to conquer strategy, which is controlled by the fuzzy system. The algorithm provides high quality solutions with the use of fuzzy decision making, which is based on nondeterministic criteria to guide the search. The fuzzy system provides a self-adjusting mechanism that eliminates the manual adjustment of parameters to each system being solved. (author)

  12. The dynamic process of atmospheric water sorption in [EMIM][Ac] and mixtures of [EMIM][Ac] with biopolymers and CO2 capture in these systems.

    Science.gov (United States)

    Chen, Yu; Sun, Xiaofu; Yan, Chuanyu; Cao, Yuanyuan; Mu, Tiancheng

    2014-10-02

    There are mainly three findings related to the dynamic process of atmospheric water sorption in the ionic liquid (IL) 1-ethyl-3-methlyl-imidazolium acetate ([EMIM][Ac]) and its mixtures with biopolymers (i.e., cellulose, chitin, and chitosan), and CO2 capture in these systems above. The analytical methods mainly include gravimetric hygroscopicity measurement and in situ infrared spectroscopy with the techniques of difference, derivative, deconvoluted attenuated total reflectance and two-dimensional correlation. These three findings are listed as below. (1) Pure [EMIM][Ac] only shows a two-regime pattern, while all the mixtures of [EMIM][Ac] with biopolymers (i.e., cellulose, chitin, and chitosan) present a three-regime tendency for the dynamic process of atmospheric water sorption. Specifically, the IL/chitosan mixture has a clear three-regime mode; the [EMIM][Ac]/chitin mixture has an unclear indiscernible regime 3; and the [EMIM][Ac]/cellulose mixture shows an indiscernible regime 2. (2) [EMIM][Ac] and its mixtures with biopolymers could physically absorb a trace amount of and chemically react with a much larger amount of CO2 from the air. The chemisorption capacity of CO2 in these pure and mixed systems is ordered as chitosan/[EMIM][Ac] mixture > chitin/[EMIM][Ac] mixture > cellulose/[EMIM][Ac] mixture > pure [EMIM][Ac] (ca. 0.09 mass ratio % g/g CO2/IL). (3) The CO2 solubility in [EMIM][Ac] decreases about 50% after being exposed to the atmospheric moist air for some specific time period.

  13. Power Supply Reliability Assessment in UPFC-installed Transmission System for ATC Enhancement Considering Transient Stability

    Science.gov (United States)

    Masuta, Taisuke; Yokoyama, Akihiko

    With recent development of power electronics technology, power system stability enhancement and optimal power flow control by using Flexible AC Transmission System (FACTS) devices have so far been studied. The FACTS devices to relieve multiple constraints can also make it possible to enhance Available Transfer Capability (ATC) without construction of new transmission lines. The previous research revealed that ATC is expanded by avoiding multiple constraints in OPF using Unified Power Flow Controller (UPFC). For long-term operation of such ATC-expanded power system, it is necessary to evaluate power system reliability. In this paper, the evaluation method of supply reliability for UPFC-installed power system is proposed. Both thermal capacity and transient stability constraints are considered. The effectiveness of the proposed method is shown by numerical examples for IEEJ East10-machine test system.

  14. Design and Analysis of the Main AC/DC Converter System for ITER

    Institute of Scientific and Technical Information of China (English)

    盛志才; 许留伟; 傅鹏

    2012-01-01

    A design of the main AC/DC converter system for ITER is described and the configuration of the main AC/DC converters is presented. To reduce the reactive power absorbed from the converter units, the main AC/DC converters are designed to be series-connected and work in a sequential mode. The structure of the regulator of the converter system is described. A simulation model was built up for the PSCAD/EMTDC code, and the design was validated accordingly. Harmonic analysis and reactive power calculation of the converters units are presented. The results reveal the advantage of sequential control in reducing reactive power and harmonics.

  15. Electric transmission line flashover prediction system

    Science.gov (United States)

    Amarh, Felix

    Near industrial, agricultural, or coastal areas, contamination is a frequent cause of insulator flashover, most cases of which result in lengthy service interruptions. Utilities spend significant amounts of money on insulator washing and cleaning before the restoration of the service. Laboratory studies and industrial experience have shown that both contamination and wetting of insulator surfaces, which initiate the flow of leakage current, are required for insulator flashover. The leakage current leading to flashover has distinctive stages of development. Flashover is preceded by dry-band arcing and extension of the arc to bridge the insulator. This combination significantly modifies both the magnitude and shape of the leakage current. A condition-based monitoring (CBM) system that monitors the easily measurable insulator leakage current as a means of assessing pollution severity and would possibly predict an approaching flashover could prove beneficial to utilities. The overall aim of this project is the development of a system that monitors pollution build-up through the signature changes in the leakage current and alerts an operator when there is a danger of flashover. The operator can, in turn, order maintenance personnel to wash the insulators. This will safeguard against unforeseen flashovers, since the system is constantly being monitored and diagnosed. Additionally, the washing cycles of insulators will be optimized, saving money and eventually rendering the power transmission system more reliable.

  16. Microfluidic system for transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ring, Elisabeth A [ORNL; De Jonge, Niels [ORNL

    2010-01-01

    We present a microfluidic system that maintains liquid flow in a specimen chamber for (scanning) transmission electron microscope ((S)TEM) imaging. The specimen chamber consists of two ultra-thin silicon nitride windows supported by silicon microchips. They are placed in a specimen holder that seals the sample from the vacuum in the electron microscope, and incorporates tubing to and from the sample connected to a syringe pump outside the microscope. Using results obtained from fluorescence microscopy of microspheres flowing through the system, an equation to characterize the liquid flow through the system was calibrated. Gold nanoparticles of diameters of 30 and 100 nm moving in liquid were imaged with a 200 kV STEM. It was concluded that despite strong influences from Brownian motion, and sensitivity to small changes in the depth of the bypass channel, the electron microscopy flow data matched the calculated flow speed within an order of magnitude. The system allows for rapid (within a minute) liquid exchange, which can potentially be used, for example, to investigate the response of specimens, e.g., eukaryotic-, or bacterial cells, to certain stimuli.

  17. A Series-LC-Filtered Active Damper for AC Power Electronics Based Power Systems

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang

    2015-01-01

    This paper proposes an active damper with a series LC-filter for suppressing resonances in an ac power electronics based power system. The added filter capacitor helps to lower the voltage stress of the converter to be used for implementing the damper. Unlike active filters for the compensation...... is built, where the damper is integrated into a grid-connected converter. The results obtained from the experiments demonstrate the stability enhancement of ac power electronics based power systems by the active damper....

  18. AC-3 audio coder

    Science.gov (United States)

    Todd, Craig

    1995-12-01

    AC-3 is a system for coding up to 5.1 channels of audio into a low bit-rate data stream. High quality may be obtained with compression ratios approaching 12-1 for multichannel audio programs. The high compression ratio is achieved by methods which do not increase decoder memory, and thus cost. The methods employed include: the transmission of a high frequency resolution spectral envelope; and a novel forward/backward adaptive bit allocation algorithm. In order to satisfy practical requirements of an emissions coder, the AC-3 syntax includes a number of features useful to broadcasters and consumers. These features include: loudness uniformity between programs; dynamic range control; and broadcaster control of downmix coefficients. The AC-3 coder has been formally selected for inclusion of the U.S. HDTV broadcast standard, and has been informally selected for several additional applications.

  19. Comparative Study of AC/DC High Voltage Transmissions%高压交直流输电比较研究

    Institute of Scientific and Technical Information of China (English)

    王红刚

    2011-01-01

    比较了高压交流输电和高压直流输电的差异,认为,输送同样的电能,高压直流输电损耗少的原因在于载流子在晶格势场中的能态低;由于载流子受到感应电场的作用,高压交流输电载流子在晶格势场中的能态将高于高压直流输电载流子的能态。不论高压交流输电还是高压直流输电都存在着趋肤效应,直流趋肤效应起源于载流子受到的霍尔电场力;交流趋肤效应起源于载流子除了受到霍尔电场力外,还受到了交变电场力的作用.%Comparing the differences between AC and DC high voltage transmissions,it is considered that the reason why the DC high voltage transmission has lower electrical loss in transmitting the same power is that its carriers have low energy state in lattice potential field.As the carriers being affected by induced electric field,carriers of AC will have higher energy state than that of DC in lattice potential field.No matter AC or DC high voltage transmission there is skin effect.The DC skin effect originates from Hall electric field force acting on the carriers,while the AC skin effect originates from not only Hall electric field,but the role of alternating electric field force.

  20. Chance-Constrained AC Optimal Power Flow for Distribution Systems With Renewables

    Energy Technology Data Exchange (ETDEWEB)

    DallAnese, Emiliano; Baker, Kyri; Summers, Tyler

    2017-09-01

    This paper focuses on distribution systems featuring renewable energy sources (RESs) and energy storage systems, and presents an AC optimal power flow (OPF) approach to optimize system-level performance objectives while coping with uncertainty in both RES generation and loads. The proposed method hinges on a chance-constrained AC OPF formulation where probabilistic constraints are utilized to enforce voltage regulation with prescribed probability. A computationally more affordable convex reformulation is developed by resorting to suitable linear approximations of the AC power-flow equations as well as convex approximations of the chance constraints. The approximate chance constraints provide conservative bounds that hold for arbitrary distributions of the forecasting errors. An adaptive strategy is then obtained by embedding the proposed AC OPF task into a model predictive control framework. Finally, a distributed solver is developed to strategically distribute the solution of the optimization problems across utility and customers.

  1. Study of ac hopping conductivity on one-dimensional nanometre systems

    Institute of Scientific and Technical Information of China (English)

    徐慧; 宋祎璞

    2002-01-01

    In this paper, we establish a one-dimensional random nanocrystalline chain model, we derive a new formula of ac electron-phonon-field conductance for electron tunnelling transfer in one-dimensional nanometre systems. By calculating the ac conductivity, the relationship between the electric field, temperature and conductivity is analysed, and the effect of crystalline grain size and distortion of interfacial atoms on the ac conductance is discussed. A characteristic of negative differential dependence of resistance and temperature in the low-temperature region for a nanometre system is found. The ac conductivity increases linearly with rising frequency of the electric field, and it tends to increase as the crystalline grain size increases and to decrease as the distorted degree of interfacial atoms increases.

  2. An embedded Video Transmission System Based on H.264

    Institute of Scientific and Technical Information of China (English)

    GAO Jing-min; LAN Ya-zhu

    2009-01-01

    In this paper,an embedded Video Transmission System based on H.264 is proposed.In this system,the latest video compression standards-H.264 is used as video codec algorithm,the i.mx27 is used as the center processors of the system,embedded Linux is used as the operating system and RTP/UDP is used as the network transmission protocol.The paper introduces the design way and the frame of the system.The test results of the system show that the proposed system can support good quality transmission of the video information.The parameters with the transmission are D1,720*480,30fps and 4Mbps.In addition,in order to ensure the security of the video information in the transmission,the system provides the encryption to the information in the process of compressing.

  3. Marketing information system online design for craftsmen small medium enterprises (case study: craftsmen ac)

    Science.gov (United States)

    Fitriana, Rina; Kurniawan, Wawan; Barlianto, Anung; Adriansyah Putra, Rizki

    2016-02-01

    AC is small and medium enterprises which is engaged in the field of crafts. This SME (Small Medium Enterprise) didn't have an integrated information system for managing sales. This research aims to design a marketing Information system online as applications that built as web base. The integrated system is made to manage sales and expand its market share. This study uses a structured analysis and design in its approach to build systems and also implemented a marketing framework of STP (Segmentation, Targeting, Positioning) and 4P (Price, Product, Place, Promotion) to obtain market analysis. The main market target customer craftsmen AC is women aged 13 years to 35 years. The products produced by AC are shoes, brooch, that are typical of the archipelago. The prices is range from Rp. 2000 until Rp. 400.000. Marketing information system online can be used as a sales transaction document, promoting the goods, and for customer booking products.

  4. Transmission techniques for emergent multicast and broadcast systems

    CERN Document Server

    da Silva, Mario Marques; Dinis, Rui; Souto, Nuno; Silva, Joao Carlos

    2010-01-01

    Describing efficient transmission schemes for broadband wireless systems, Transmission Techniques for Emergent Multicast and Broadcast Systems examines advances in transmission techniques and receiver designs capable of supporting the emergent wireless needs for multimedia broadcast and multicast service (MBMS) requirements. It summarizes the research and development taking place in wireless communications for multimedia MBMS and addresses the means to improved spectral efficiency to allow for increased user bit rate, as well as increased capacity of the digital cellular radio network.The text

  5. Artificial Cooperative Search Algorithm based Load Frequency Control of Interconnected Power Systems with AC-DC Tie-lines

    Directory of Open Access Journals (Sweden)

    S. Ramesh kumar

    2014-05-01

    Full Text Available A maiden effort for optimal tuning of load frequency controller parameters using Artificial Cooperative Search (ACS algorithm for a two area interconnected power system with AC-DC parallel tie-lines has been presented in this paper. ACS is a recent swarm intelligence algorithm developed for solving numerical optimization problems. The swarm intelligence philosophy behind ACS algorithm is based on the migration of two artificial superorganisms as they biologically interact to achieve the global minimum value pertaining to the problem. The HVDC link in parallel with AC tie-line is used as system interconnection to effectively damp the frequency oscillations of the AC system. An integral square error criterion (ISE has been used as performance index to design the optimal parameters. A comparative study of tuned values has been presented to show the effectiveness of the Artificial Cooperative Search algorithm. The results demonstrate the success of ACS algorithm in solving Load frequency control (LFC optimization problem.

  6. Fault ride-through and grid support of permanent magnet synchronous generator-based wind farms with HVAC and VSC-HVDC transmission systems

    DEFF Research Database (Denmark)

    Liu, Hongzhi; Chen, Zhe

    2012-01-01

    This paper describes fault ride-through and grid support of offshore wind farms based on permanent magnet synchronous generator (PMSG) wind turbines connected to the onshore AC network through two alternative transmission systems: high voltage AC (HVAC) or high voltage DC (HVDC) based on voltage...... source converters (VSC). The proposed configurations of the PMSG-based offshore wind farm and VSC-based HVDC are given as well as their control strategies under both steady state and fault state. The PMSG-based offshore wind farm is integrated into a test power transmission system via either HVAC or VSC-HVDC...

  7. MIMO Identical Eigenmode Transmission System (IETS) - A Channel Decomposition Perspective

    CERN Document Server

    Shakir, M Zeeshan

    2010-01-01

    In the past few years considerable attention has been given to the design of Multiple-Input Multiple-Output (MIMO) Eigenmode Transmission Systems (EMTS). This paper presents an in-depth analysis of a new MIMO eigenmode transmission strategy. The non-linear decomposition technique called Geometric Mean Decomposition (GMD) is employed for the formation of eigenmodes over MIMO flatfading channel. Exploiting GMD technique, identical, parallel and independent transmission pipes are created for data transmission at higher rate. The system based on such decomposition technique is referred to as MIMO Identical Eigenmode Transmission System (IETS). The comparative analysis of the MIMO transceiver design exploiting nonlinear and linear decomposition techniques for variable constellation is presented in this paper. The new transmission strategy is tested in combination with the Vertical Bell Labs Layered Space Time (V-BLAST) decoding scheme using different number of antennas on both sides of the communication link. The ...

  8. 47 CFR 73.49 - AM transmission system fencing requirements.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false AM transmission system fencing requirements. 73.49 Section 73.49 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES AM Broadcast Stations § 73.49 AM transmission system fencing...

  9. 47 CFR 73.44 - AM transmission system emission limitations.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false AM transmission system emission limitations. 73... SERVICES RADIO BROADCAST SERVICES AM Broadcast Stations § 73.44 AM transmission system emission limitations. (a) The emissions of stations in the AM service shall be attenuated in accordance with the...

  10. Harmonic detection an AC excited generation system based on in-phase correlation filtering

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The paper reports results of investigation on the harmonic detection technique of a complicated power supply system such as an AC excited generation system, which has a variable fundamental frequency and low order harmonics with rich sub-harmonics whose frequencies are lower than the fundamental one. The in-phase correlation filtering technique, based on the frequency shifting principle, is proposed in this paper. Theoretical analysis and experimental results validate the effectiveness of this technique for the harmonic detections of AC excited generation systems.

  11. Study of the DEF Feedback Control System in AC Operation of Superconducting Tokamak

    Institute of Scientific and Technical Information of China (English)

    WANG Hua; LUO Jiarong; YUAN Qiping; XU Congdong

    2007-01-01

    AC operation with multiple full cycles has been successfully performed on the superconducting tokamak HT-7. In the experiment, it was discovered that the saturation of the transformer magnetic flux with DEF, a signal name, was one of key aspects that affected the AC operation. The conditions of DEF were examined through the DEF feedback control system. By controlling the working patterns of the subsystems, namely the poloidal field control system and density control system, it was guaranteed that DEF would remain in the non-saturated status.

  12. Techniques for detecting proximity to voltage collapse in AC/DC systems

    Energy Technology Data Exchange (ETDEWEB)

    Canizares, Claudio A. [Escuela Politecnica Nacional, Quito (Ecuador); Long, Willis F.; Alvarado, Fernando L.; DeMarco, CChristopher L. [Wisconsin Univ., Madison, WI (United States)

    1992-12-31

    This paper describes three different techniques to detect proximity to voltage collapse (saddle-node bifurcation) in AC/DC systems; namely, direct (point of collapse) methods, continuation methods, and transient energy function methods. These techniques are compared among them, and also against the voltage sensitivity factor method using a 173 bus ac/dc test system. Various operational conditions are considered for this test system, so that transfer capabilities between areas and the effects of HVDC links can be analysed from the point of view of voltage collapse. 24 refs., 7 figs.

  13. Harmonic detection an AC excited generation system based on in-phase correlation filtering

    Institute of Scientific and Technical Information of China (English)

    贺益康; 孙丹; 王文举; 石赟

    2002-01-01

    The paper reports results of investigation on the harmonic detection technique of a complicated power supply system such as an AC excited generation system, which has a variable fundamental frequency and low order harmonics with rich sub-harmonics whose frequencies are lower than the fundamental one. The in-phase correlation filtering technique, based on the frequency shifting principle, is proposed in this paper.Theoretical analysis and experimental results validate the effectiveness of this technique for the harmonic detections of AC excited generation systems.

  14. Optimization of transmission system design based on genetic algorithm

    Directory of Open Access Journals (Sweden)

    Xianbing Chen

    2016-05-01

    Full Text Available Transmission system is a crucial precision mechanism for twin-screw chemi-mechanical pulping equipment. The structure of the system designed by traditional method is not optimal because the structure designed by the traditional methods is easy to fall into the local optimum. To achieve the global optimum, this article applies the genetic algorithm which has grown in recent years in the field of structure optimization. The article uses the volume of transmission system as the objective function to optimize the structure designed by traditional method. Compared to the simulation results, the original structure is not optimal, and the optimized structure is tighter and more reasonable. Based on the optimized results, the transmission shafts in the transmission system are designed and checked, and the parameters of the twin screw are selected and calculated. The article provided an effective method to design the structure of transmission system.

  15. Nonlinear system guidance in the presence of transmission zero dynamics

    Science.gov (United States)

    Meyer, G.; Hunt, L. R.; Su, R.

    1995-01-01

    An iterative procedure is proposed for computing the commanded state trajectories and controls that guide a possibly multiaxis, time-varying, nonlinear system with transmission zero dynamics through a given arbitrary sequence of control points. The procedure is initialized by the system inverse with the transmission zero effects nulled out. Then the 'steady state' solution of the perturbation model with the transmission zero dynamics intact is computed and used to correct the initial zero-free solution. Both time domain and frequency domain methods are presented for computing the steady state solutions of the possibly nonminimum phase transmission zero dynamics. The procedure is illustrated by means of linear and nonlinear examples.

  16. Electromechanical systems with transient high power response operating from a resonant ac link

    Science.gov (United States)

    Burrows, Linda M.; Hansen, Irving G.

    1992-01-01

    The combination of an inherently robust asynchronous (induction) electrical machine with the rapid control of energy provided by a high frequency resonant ac link enables the efficient management of higher power levels with greater versatility. This could have a variety of applications from launch vehicles to all-electric automobiles. These types of systems utilize a machine which is operated by independent control of both the voltage and frequency. This is made possible by using an indirect field-oriented control method which allows instantaneous torque control all four operating quadrants. Incorporating the ac link allows the converter in these systems to switch at the zero crossing of every half cycle of the ac waveform. This zero loss switching of the link allows rapid energy variations to be achieved without the usual frequency proportional switching loss. Several field-oriented control systems were developed under contract to NASA.

  17. 40 Gb/s optical transmission systems

    DEFF Research Database (Denmark)

    Buxens Azcoaga, Alvaro Juan; Nielsen, Steen Krogh

    2003-01-01

    application (maximum distance of 40 km) the maximum PMD coeficient allowed in the transmission fiber, 0.4 ps=pkm, is below the values defined by actual standards, 0.5 ps=pkm. The most promising PMD compensation methods are presented and their advantages and disadvantages are discussed. A PMD compensator based...

  18. Measurement of Transmission Error Including Backlash in Angle Transmission Mechanisms for Mechatronic Systems

    Science.gov (United States)

    Ming, Aiguo; Kajitani, Makoto; Kanamori, Chisato; Ishikawa, Jiro

    The characteristics of angle transmission mechanisms exert a great influence on the servo performance in the robotic or mechatronic mechanism. Especially, the backlash of angle transmission mechanism is preferable the small amount. Recently, some new types of gear reducers with non-backlash have been developed for robots. However, the measurement and evaluation method of the backlash of gear trains has not been considered except old methods which can statically measure at only several meshing points of gears. This paper proposes an overall performance testing method of angle transmission mechanisms for the mechatronic systems. This method can measure the angle transmission error both clockwise and counterclockwise. In addition the backlash can be continuously measured in all meshing positions automatically. This system has been applied to the testing process in the production line of gear reducers for robots, and it has been effective for reducing the backlash of the gear trains.

  19. ±800 kV直流输电工程交流滤波器暂态定值计算%Transient Rating Calculation of AC Filters in ±800 kV UHV DC Transmission Project

    Institute of Scientific and Technical Information of China (English)

    李璟延; 杨一鸣; 吴方劼

    2013-01-01

    特高压直流输电工程换流器运行中会产生大量谐波,对电力系统稳定和通信线路等均会造成不良影响.加装交流滤波器可以有效地降低换流器谐波危害,提高系统运行可靠性,同时补偿换流器运行中所需的无功.为了使交流滤波器在各种工况下都能安全运行,必须合理地配置避雷器并确定滤波器的绝缘配合方案.本文根据±800 kV特高压直流输电工程功能规范书的要求和交流滤波器元件参数特性,选取最严酷的运行工况,计算了交流滤波器暂态负荷情况,研究得出了交流滤波器内各元件电容、电抗、电阻以及避雷器的暂态电流、电压和能量,确定了交流滤波器各元件的绝缘水平和避雷器参数配置,得出整流站和逆变站高压容器雷电耐受水平和操作耐受水平分别为1550 kV和1175 kV.研究表明通过合理确定绝缘水平并配置避雷器,可以有效地降低滤波器设备电容器、电抗器和电阻器的保护水平,同时满足交流滤波器设备安全运行要求.%The converter will produce a large number of harmonics in UHV DC transmission project, which can impact the stability of power system and communication lines. The AC filters can effectively reduce the hazards of harmonics and improve the system reliability, and at the same time compensate the reactive power requirements of the converters. To ensure the safe operation of AC filters in a variety of conditions, it is reasonable and significant to configure the arresters and also to determine the insulation coordination for AC filters. Thus, according to the requirements of +800 kV UHV DC transmission project and the characteristics of AC filter components under the most severe operating conditions, the transient rating of AC filters were calculated. The transient currents, voltages and energies of AC filters components such as capacitances, reactors, resistors and arresters were determined. The insulation level of

  20. Security of the data transmission in the industrial control system

    Directory of Open Access Journals (Sweden)

    Marcin Bednarek

    2015-12-01

    Full Text Available The theme of this paper is to present the data transmission security system between the stations of the industrial control system. The possible options for secure communications between process stations, as well as between process and operator station are described. Transmission security mechanism is based on algorithms for symmetric and asymmetric encryption. The authentication process uses a software token algorithm and a one-way hash function. The algorithm for establishing a secured connection between the stations, including the authentication process and encryption of data transmission is given. The process of securing the transmission consists of 4 sub-processes: (I authentication; (II asymmetric, public keys transmission; (III symmetric key transmission; (IV data transmission. The presented process of securing the transmission was realized in the industrial controller and emulator. For this purpose, programming languages in accordance with EN 61131 were used. The functions were implemented as user function blocks. This allows us to include a mixed code in the structure of the block (both: ST and FBD. Available function categories: support of the asymmetric encryption; asymmetric encryption utility functions; support of the symmetric encryption; symmetric encryption utility functions; support of the hash value calculations; utility functions of conversion.[b]Keywords[/b]: transmission security, encryption, authentication, industrial control system

  1. Simplification Study of FE Model for 1000kV AC Transmission Line Insulator String Voltage and Grading Ring Surface Electric Field Distribution Calculation

    Directory of Open Access Journals (Sweden)

    Guoli Wang

    2013-09-01

    Full Text Available The finite element model of the 1000kV Ultra High Voltage (UHV AC transmission line porcelain insulator string voltage distribution and grading ring surface electric field distribution calculation has the characteristics of large size, complicated structure and various mediums. To insure the accuracy, related influencing factors should be considered to simplify the model reasonably for improving computational efficiency. A whole model and a simplified 3D finite element model of UHV AC transmission line porcelain insulator string were built. The influencing factors including tower, phase conductors, hardware fittings, yoke plate and phase interaction were considered in the analysis. And finally, the rationality of the simplified model was validated. The results comparison show that building a simplified model of three-phase bundled conductors within a certain length, simplifying the tower reasonably, omitting the hardware fittings and yoke plate and containing only single-phase insulator string model is feasible. The simplified model could replace the whole model to analyze the voltage distribution along the porcelain insulator string and the electric field distribution on the grading ring surface, and it can reduce the calculation scale, improve optimization efficiency of insulators string and grading ring parameters.

  2. Influence of Load Modes on Voltage Stability of Receiving Network at DC/AC System

    Directory of Open Access Journals (Sweden)

    Mao Chizu

    2016-01-01

    Full Text Available This paper analyses influence of load modes on DC/AC system. Because of widespread use of HVDC, DC/AC system become more complex than before and the present modes used in dispatch and planning departments are not fit in simulation anymore. So it is necessary to find load modes accurately reflecting characteristics of the system. For the sake of the voltage stability, commutation failure, etc. the practical example of the receiving network in a large DC/AC system in China is simulated with BPA, and the influence of Classical Load Mode (CLM and Synthesis load model (SLM on simulation results is studies. Furthermore, some important parameters of SLM are varied respectively among an interval to analyse how they affect the system. According to this practical examples, the result is closely related to load modes and their parameters, and SLM is more conservative but more reasonable than the present modes. The consequences indicate that at critical states, micro variation in parameters may give rise to change in simulation results radically. Thus, correct mode and parameters are important to enhance simulation accuracy of DC/AC system and researches on how they affect the system make senses.

  3. Modelling and control of hybrid renewable energy system connected to AC grid

    Directory of Open Access Journals (Sweden)

    Sami Younsi

    2011-12-01

    Full Text Available This paper discusses the development of new control and supervision method for the optimum operation of hybrid renewable energy system (HRES connected to AC grid. The hybrid system consists of wind generator (WG, diesel generator (DG, and flywheel energy storage system (FESS. These subsystems are based on permanent magnet synchronous machines (PMSM which are controlled by sliding mode control. A supervisor control is designed to determine the energy transfer type of flywheel energy storage system (charging / discharging / no transfer energy, to take decision on diesel generators ON/OFF status, and to determine the reference powers for these two subsystems. The supervisor inputs are the power requested by AC grid, the power generated by wind generator, and the energy stored in flywheel. The objectives of the control and supervision for hybrid renewable energy system are to satisfy the power requested by AC grid, to manage the energy transfer between hybrid system and AC grid, to optimize the use of wind energy, and to reduce fuel of diesel generator. The system is simulated with Matlab – Simulink software and it gave good results.

  4. Strategic Generation with Conjectured Transmission Price Responses in a Mixed Transmission Pricing System. Part 1. Formulation

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, B.F. [Department of Geography and Environmental Engineering, The Johns Hopkins University, Baltimore, MD (United States); Rijkers, F.A.M. [Office of Energy Regulation DTe, Den Haag (Netherlands)

    2004-05-01

    The conjectured supply function (CSF) model calculates an oligopolistic equilibrium among competing generating companies (GenCos), presuming that GenCos anticipate that rival firms will react to price increases by expanding their sales at an assumed rate. The CSF model is generalized here to include each generator's conjectures concerning how the price of transmission services (point-to-point service and constrained interfaces) will be affected by the amount of those services that the generator demands. This generalization reflects the market reality that large producers will anticipate that they can favorably affect transmission prices by their actions. The model simulates oligopolistic competition among generators while simultaneously representing a mixed transmission pricing system. This mixed system includes fixed transmission tariffs, congestion-based pricing of physical transmission constraints (represented as a linearized dc load flow), and auctions of interface capacity in a path-based pricing system. Pricing inefficiencies, such as export fees and no credit for counterflows, can be simulated. The model is formulated as a linear mixed complementarity problem, which enables very large market models to be solved. In the second paper of this two-paper series, the capabilities of the model are illustrated with an application to northwest Europe, where transmission pricing is based on such a mixture of approaches.

  5. Autonomous Active Power Control for Islanded AC Microgrids with Photovoltaic Generation and Energy Storage System

    DEFF Research Database (Denmark)

    Wu, Dan; Tang, Fen; Dragicevic, Tomislav;

    2014-01-01

    , an autonomous active power control strategy is proposed for AC islanded microgrids in order to achieve power management in a decentralized manner. The proposed control algorithm is based on frequency bus-signaling of ESS and uses only local measurements for power distribution among microgrid elements. Moreover......, this paper also presents a hierarchical control structure for AC microgrids that is able to integrate the ESS, PV systems and loads. Hereby, basic power management function is realized locally in primary level, while strict frequency regulation can be achieved by using additional secondary controller......In an islanded AC microgrid with distributed energy storage system (ESS), photovoltaic (PV) generation and loads, a coordinated active power regulation is required to ensure efficient utilization of renewable energy, while keeping the ESS from overcharge and over discharge conditions. In this paper...

  6. Methods, systems and apparatus for controlling operation of two alternating current (AC) machines

    Science.gov (United States)

    Gallegos-Lopez, Gabriel; Nagashima, James M.; Perisic, Milun; Hiti, Silva

    2012-02-14

    A system is provided for controlling two AC machines. The system comprises a DC input voltage source that provides a DC input voltage, a voltage boost command control module (VBCCM), a five-phase PWM inverter module coupled to the two AC machines, and a boost converter coupled to the inverter module and the DC input voltage source. The boost converter is designed to supply a new DC input voltage to the inverter module having a value that is greater than or equal to a value of the DC input voltage. The VBCCM generates a boost command signal (BCS) based on modulation indexes from the two AC machines. The BCS controls the boost converter such that the boost converter generates the new DC input voltage in response to the BCS. When the two AC machines require additional voltage that exceeds the DC input voltage required to meet a combined target mechanical power required by the two AC machines, the BCS controls the boost converter to drive the new DC input voltage generated by the boost converter to a value greater than the DC input voltage.

  7. Equal pulse width chopping control based on plugged pulse principle in three-phase AC/AC system%基于脉冲阻塞原理的三相AC/AC系统等脉宽斩波控制

    Institute of Scientific and Technical Information of China (English)

    郑诗程; 陈玲; 曹小虎

    2011-01-01

    A circuit topology of three-phase AC/AC system is presented,which needs only six power devices to realize the three-phase AC/AC frequency conversion. The traditional phase-shifted control strategy is replaced by the equal pulse width chopping control strategy based on plugged pulse principle to regulate the amplitude and frequency of output voltage separately or simultaneously. The equal pulse width chopping control strategy is analyzed in detail and the mathematic expression of duty cycle is deduced based on the area equivalent rule according to different frequency and amplitude of anticipant output voltage. Under the environment of PSPICE,the three-phase AC/AC system with the equal pulse width chopping control strategy is simulated. Its main circuit and FPGA-based control circuit are designed and tested. The experimental results are consistent with the simulative results,completely same as the theoretical analysis,which verifies the correctness and feasibility of the introduced control strategy.%针对传统的三相AC/AC变频电路特点,提出了一种新的电路拓扑,仅用6个功率器件即可实现三相AC/AC变频功能.提出基于脉冲阻塞原理的等脉宽斩波控制策略,取代传统的移相控制策略施加于该电路拓扑,实现了三相输出电压幅值、频率分别可调或同时可调.对等脉宽斩波控制策略进行了详细的理论分析.根据期望输出电压的不同频率和幅值.利用面积等效原则,推导出相应占空比的数学表达式.在PSPICE环境下根据脉冲阻塞原理.对三相AC/AC系统进行等脉宽斩波控制仿真.并设计了三相AC/AC系统主电路和基于FPGA的控制电路,完成了相关实验.仿真和实验结果一致,与文中的理论分析结果也完全一致,验证了该AC/AC变频控制策略的正确性及可行性.

  8. HVDC power transmission technology assessment

    Energy Technology Data Exchange (ETDEWEB)

    Hauth, R.L.; Tatro, P.J.; Railing, B.D. [New England Power Service Co., Westborough, MA (United States); Johnson, B.K.; Stewart, J.R. [Power Technologies, Inc., Schenectady, NY (United States); Fink, J.L.

    1997-04-01

    The purpose of this study was to develop an assessment of the national utility system`s needs for electric transmission during the period 1995-2020 that could be met by future reduced-cost HVDC systems. The assessment was to include an economic evaluation of HVDC as a means for meeting those needs as well as a comparison with competing technologies such as ac transmission with and without Flexible AC Transmission System (FACTS) controllers. The role of force commutated dc converters was to be assumed where appropriate. The assessment begins by identifying the general needs for transmission in the U.S. in the context of a future deregulated power industry. The possible roles for direct current transmission are then postulated in terms of representative scenarios. A few of the scenarios are illustrated with the help of actual U.S. system examples. non-traditional applications as well as traditional applications such as long lines and asynchronous interconnections are discussed. The classical ``break-even distance`` concept for comparing HVDC and ac lines is used to assess the selected scenarios. The impact of reduced-cost converters is reflected in terms of the break-even distance. This report presents a comprehensive review of the functional benefits of HVDC transmission and updated cost data for both ac and dc system components. It also provides some provocative thoughts on how direct current transmission might be applied to better utilize and expand our nation`s increasingly stressed transmission assets.

  9. Underwater Acoustic Image Transmission System Based on DSP

    Institute of Scientific and Technical Information of China (English)

    Cheng En; Xu Ru

    2002-01-01

    The underwater acoustic image transmission system based on the high-speed DSP device TMS320C549 has been studied. We use Goertzel algorithm for source decoding and MFSK for modulation. Turbo code is used for channel coding and decoding. The purpose is to implement underwater video image data transmission.

  10. Distance Protection of Cross-Bonded Transmission Cable-Systems

    DEFF Research Database (Denmark)

    Bak, Claus Leth; F. Jensen, Christian

    2014-01-01

    In this paper the problems of protecting a cross-bonded cable system using distance protection are analysed. The combination of the desire to expand the high voltage transmission grid and the public's opinion towards new installations of overhead lines (OHL), more and more transmission cable syst...

  11. INFORMATION-MEASURING TEST SYSTEM OF DIESEL LOCOMOTIVE HYDRAULIC TRANSMISSIONS

    Directory of Open Access Journals (Sweden)

    I. V. Zhukovytskyy

    2015-08-01

    Full Text Available Purpose. The article describes the process of developing the information-measuring test system of diesel locomotives hydraulic transmission, which gives the possibility to obtain baseline data to conduct further studies for the determination of the technical condition of diesel locomotives hydraulic transmission. The improvement of factory technology of post-repair tests of hydraulic transmissions by automating the existing hydraulic transmission test stands according to the specifications of the diesel locomotive repair enterprises was analyzed. It is achieved based on a detailed review of existing foreign information-measuring test systems for hydraulic transmission of diesel locomotives, BelAZ earthmover, aircraft tug, slag car, truck, BelAZ wheel dozer, some brands of tractors, etc. The problem for creation the information-measuring test systems for diesel locomotive hydraulic transmission is being solved, starting in the first place from the possibility of automation of the existing test stand of diesel locomotives hydraulic transmission at Dnipropetrovsk Diesel Locomotive Repair Plant "Promteplovoz". Methodology. In the work the researchers proposed the method to create a microprocessor automated system of diesel locomotives hydraulic transmission stand testing in the locomotive plant conditions. It acts by justifying the selection of the necessary sensors, as well as the application of the necessary hardware and software for information-measuring systems. Findings. Based on the conducted analysis there was grounded the necessity of improvement the plant hydraulic transmission stand testing by creating a microprocessor testing system, supported by the experience of developing such systems abroad. Further research should be aimed to improve the accuracy and frequency of data collection by adopting the more modern and reliable sensors in tandem with the use of filtering software for electromagnetic and other interference. Originality. The

  12. Nanoscale zero-valent iron/AC as heterogeneous Fenton catalysts in three-dimensional electrode system.

    Science.gov (United States)

    Zhang, Chao; Zhou, Lei; Yang, Jie; Yu, Xinmin; Jiang, Yonghai; Zhou, Minghua

    2014-01-01

    In the present work, nanoscale zero-valent iron/activated carbon (NZVI/AC) was investigated as heterogeneous Fenton catalyst in three-dimensional (3D) electrode system for methyl orange (MO) degradation. Some important operating parameters such as cathodic potential, pH, and O₂ flow rate were investigated, exhibiting good decolorization. The mineralization of MO was significantly improved by 20-35% compared to two-dimensional (2D) AC system at the optimum conditions. Although the TOC removal of AC was higher than NZVI/AC due to its good adsorption capacity initially, heterogeneous Fenton catalysis played a more and more important roles in the following test. After eight runs, NZVI/AC still exhibited excellent catalytic properties with low iron leaching. Further, a relatively comprehensive mechanism of NZVI/AC as particle electrodes in 3D system was proposed.

  13. Power-supply-operations group-training programs, ac/dc power systems and micellaneous information

    Energy Technology Data Exchange (ETDEWEB)

    Harris, C A

    1978-06-30

    This program introduces the technician to three phase a-c power and its relationship to rectifier power conversion systems. A brief introduction is given as to the engineering significance of various parameters such as, phase rotation, ac power relationships, harmonics, transformer voltage vectors, rectifier parameters, filters, water cooling, phase delayed triggers to SCR's, dielectric stress vs life and other related subjects. The significance of the details as they apply to various diagnostic problems that a technician may be called upon to solve is emphasized. Reference CAPE-2747.

  14. Model of Bi-directional Flyback Converter for Hybrid AC/DC Distribution System

    Directory of Open Access Journals (Sweden)

    Riku Pasonen

    2013-12-01

    Full Text Available In this article, a simulation model and concept of two switch bi-directional isolated DC/DC converter is presented. Converter is based on flyback converter type. Also control method for voltage regulation with bi-directional power transfer is presented. Target application of the proposed converter was selected to be a hybrid AC/DC distribution system concept of which was briefly described. The requirement of galvanic isolation in the hybrid AC/DC concept comes from use of shared neutral wire; DC current runs with unbalanced part of AC current in neutral wire. Without galvanic isolation grounded neutral would cause short circuit if DC/DC converter is connected to three phase rectifier or inverter. Simulation was carried out with PSCAD electromagnetic transient simulator.

  15. Compensation methods applied in current control schemes for large AC drive systems

    DEFF Research Database (Denmark)

    Rus, D. C.; Preda, N. S.; Teodorescu, Remus;

    2012-01-01

    The paper deals with modified PI current control structures for large AC drive systems which use surface mounted permanent magnet synchronous machines or squirrel-cage induction motors supplied with voltage source inverters. In order to reduce the power losses caused by high frequency switching...

  16. Modeling and Analysis of Harmonic Stability in an AC Power-Electronics-Based Power System

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Blaabjerg, Frede; Wu, Weimin

    2014-01-01

    This paper addresses the harmonic stability caused by the interactions among the wideband control of power converters and passive components in an AC power-electronicsbased power system. The impedance-based analytical approach is employed and expanded to a meshed and balanced threephase network...

  17. Digital Signal Processor System for AC Power Drivers

    OpenAIRE

    Ovidiu Neamtu

    2009-01-01

    DSP (Digital Signal Processor) is the bestsolution for motor control systems to make possible thedevelopment of advanced motor drive systems. The motorcontrol processor calculates the required motor windingvoltage magnitude and frequency to operate the motor atthe desired speed. A PWM (Pulse Width Modulation)circuit controls the on and off duty cycle of the powerinverter switches to vary the magnitude of the motorvoltages.

  18. Digital Signal Processor System for AC Power Drivers

    Directory of Open Access Journals (Sweden)

    Ovidiu Neamtu

    2009-10-01

    Full Text Available DSP (Digital Signal Processor is the bestsolution for motor control systems to make possible thedevelopment of advanced motor drive systems. The motorcontrol processor calculates the required motor windingvoltage magnitude and frequency to operate the motor atthe desired speed. A PWM (Pulse Width Modulationcircuit controls the on and off duty cycle of the powerinverter switches to vary the magnitude of the motorvoltages.

  19. Optimization Control of Bidirectional Cascaded DC-AC Converter Systems

    DEFF Research Database (Denmark)

    Tian, Yanjun

    in different power flow directions, a bidirectional impedance control method is also proposed to unify and improve the system stability. Control system type number is also analyzed in this thesis, then a symmetric proportional control method for the two stage cascaded converter is proposed to reduce the dc...

  20. The Effect of Using a Modified A/C System on the Cooling System Temperature of an Internal Combustion Engine

    Directory of Open Access Journals (Sweden)

    Mukhtar M.A. Morad

    2017-05-01

    Full Text Available This study investigates the effect of using A/C refrigerant to reduce the temperature of the coolant in a vehicle cooling system. An increase in coolant temperature due to harsh working conditions increases fuel consumption and leads to a reduction in engine power. Modifying vehicle air-conditioning by passing the suction line of the A/C system through the heat exchanger located in the lower part of the radiator (down flow type can significantly improve the performance of the engine cooling system. The results show a reduction in the temperature of coolant within the cooling system, thus maintaining a controlled working temperature within the allowable limits

  1. Vibration transmissibility characteristics of smart spring vibration isolation system

    Institute of Scientific and Technical Information of China (English)

    倪德; 朱如鹏; 陆凤霞; 鲍和云; 付秋菊

    2014-01-01

    The objective of this work was to study the vibration transmissibility characteristics of the undamped and damped smart spring systems. The frequency response characteristics of them were analyzed by using the equivalent linearization technique, and the possible types of the system motion were distinguished by using the starting and ending frequencies. The influences of system parameters on the vibration transmissibility characteristics were discussed. The following conclusions may be drawn from the analysis results. The undamped smart spring system may simultaneously have one starting frequency and one ending frequency or only have one starting frequency, and the damped system may simultaneously have two starting frequencies and one ending frequency. There is an optimal control parameter to make the peak value of the vibration transmissibility curve of the system be minimum. When the mass ratio is far away from the stiffness ratio, the vibration transmissibility is small. The effect of the damping ratio on the system vibration transmissibility is significant while the control parameter is less than its optimal value. But the influence of the relative damping ratio on the vibration transmissibility is small.

  2. Design of MAGLEV Information Transmission System by Radio Inductive Loop

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Sang Kweun [Taejon National University of Technology (Korea, Republic of); Park, Seok Ha; Kim, Jong Bum; Kim, Yang Mo [Chungnam National University (Korea, Republic of); Park, Jeong Soo [ACE Technology (Korea, Republic of)

    1999-01-01

    This paper presents the information transmission between on-board and ground-site in MAGLEV Considering safety and high speed operation and density operation and density operation information, transmission between them is necessary. Therefore it is necessary for transmission system to ensure high speed transmission, low error rate, massive information, and reliability of information. To provide above conditions, 1.1km signal line assembly was constructed and Frequency Shift Keying(FSK) modulation and Open System Interconnection(OSI) based high-level data link control(HDLC) protocol are applied, To modulate digital signal for transmission from ground-site to on-board, carrier frequency of 70khz is used and 90khz is used for transmission from on-board to ground-site. Transmission speed is 2400bps for consideration of train speed, quantity of information, and data error rate. And this paper introduces information monitoring considering user interface and presents the method for an effective data transmission in MAGLEV which is now being tested and intends to provide for an intelligent train operation in future. (author). 9 refs., 9 figs., 1 tab.

  3. System and method for monitoring and controlling stator winding temperature in a de-energized AC motor

    Science.gov (United States)

    Lu, Bin; Luebke, Charles John; Habetler, Thomas G.; Zhang, Pinjia; Becker, Scott K.

    2011-12-27

    A system and method for measuring and controlling stator winding temperature in an AC motor while idling is disclosed. The system includes a circuit having an input connectable to an AC source and an output connectable to an input terminal of a multi-phase AC motor. The circuit further includes a plurality of switching devices to control current flow and terminal voltages in the multi-phase AC motor and a controller connected to the circuit. The controller is configured to activate the plurality of switching devices to create a DC signal in an output of the motor control device corresponding to an input to the multi-phase AC motor, determine or estimate a stator winding resistance of the multi-phase AC motor based on the DC signal, and estimate a stator temperature from the stator winding resistance. Temperature can then be controlled and regulated by DC injection into the stator windings.

  4. Alternative electrical transmission systems and their environmental impact

    Energy Technology Data Exchange (ETDEWEB)

    Schiefelbein, G.F.

    1977-08-01

    A general description is provided of electrical transmission systems as an aid in determining their environmental impacts. Alternating current, direct current, overhead systems, underground systems, and water crossings are treated. The cost, performance, reliability, safety, and environmental impact of these systems are compared.

  5. Critical Length Criterion and the Arc Chain Model for Calculating the Arcing Time of the Secondary Arc Related to AC Transmission Lines

    Science.gov (United States)

    Cong, Haoxi; Li, Qingmin; Xing, Jinyuan; Li, Jinsong; Chen, Qiang

    2015-06-01

    The prompt extinction of the secondary arc is critical to the single-phase reclosing of AC transmission lines, including half-wavelength power transmission lines. In this paper, a low-voltage physical experimental platform was established and the motion process of the secondary arc was recorded by a high-speed camera. It was found that the arcing time of the secondary arc rendered a close relationship with its arc length. Through the input and output power energy analysis of the secondary arc, a new critical length criterion for the arcing time was proposed. The arc chain model was then adopted to calculate the arcing time with both the traditional and the proposed critical length criteria, and the simulation results were compared with the experimental data. The study showed that the arcing time calculated from the new critical length criterion gave more accurate results, which can provide a reliable criterion in term of arcing time for modeling and simulation of the secondary arc related with power transmission lines. supported by National Natural Science Foundation of China (Nos. 51277061 and 51420105011)

  6. Cost estimation of HVDC transmission system of Bangka's NPP candidates

    Science.gov (United States)

    Liun, Edwaren; Suparman

    2014-09-01

    Regarding nuclear power plant development in Bangka Island, it can be estimated that produced power will be oversupply for the Bangka Island and needs to transmit to Sumatra or Java Island. The distance between the regions or islands causing considerable loss of power in transmission by alternating current, and a wide range of technical and economical issues. The objective of this paper addresses to economics analysis of direct current transmission system to overcome those technical problem. Direct current transmission has a stable characteristic, so that the power delivery from Bangka to Sumatra or Java in a large scale efficiently and reliably can be done. HVDC system costs depend on the power capacity applied to the system and length of the transmission line in addition to other variables that may be different.

  7. Transmission Reinforcements in the Central American Regional Power System

    Energy Technology Data Exchange (ETDEWEB)

    Elizondo, Marcelo A.; Vallem, Mallikarjuna R.; Samaan, Nader A.; Makarov, Yuri V.; Vyakaranam, Bharat; Nguyen, Tony B.; Munoz, Christian; Herrera, Ricardo; Midence, Diego; Shpitsberg, Anna

    2016-07-25

    The Central American regional interconnected power system (SER) connects the countries members of the Central American regional electricity market (MER): Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica, and Panama. The SER was a result of a long term regional effort, and was initially conceived to transfer 300 MW between countries. However, the current transfer limits between countries range from 70 MW to 300 MW. Regional entities, like CRIE (Regional Commission of Electrical Interconnection), EOR (Central American Regional System Operator), and CDMER (Board of Directors of the Central American Market) are working on coordinating the national transmission expansion plans with regional transmission planning efforts. This paper presents experience in Central America region to recommend transmission reinforcements to achieve 300 MW transfer capacity between any pair of member countries of the Central American regional electricity market (MER). This paper also provides a methodology for technical analysis and for coordination among the regional and national entities. This methodology is unique for transmission systems of these characteristics.

  8. Open access pricing methodology in economically adapted electric transmission systems

    Energy Technology Data Exchange (ETDEWEB)

    Rudnick, Hugh; Cura, Eliana; Palma, Rodrigo [Pontificia Univ. Catolica de Chile, Santiago (Chile). Dept. de Ingenieria Electrica

    1996-07-01

    Open access pricing methodologies are evaluated in a deregulated environment, as applied to an economically adapted electric transmission system over a ten year time horizon. A transmission planning methodology using a genetic algorithm is used to determine the adapted system and the required investment over the horizon. A production cost simulation algorithm is utilized to determine the operation of the hydroelectric system and the resultant short term marginal income. Different pricing methodologies to allocate the required supplement, as applied to the Chilean central interconnected electrical system, are evaluated: use of system, postage stamp and user benefit. The resultant payment allocations are assessed and their economic impact on participants is discussed. (author)

  9. Transmission line component testing for the ITER Ion Cyclotron Heating and Current Drive System

    Science.gov (United States)

    Goulding, Richard; Bell, G. L.; Deibele, C. E.; McCarthy, M. P.; Rasmussen, D. A.; Swain, D. W.; Barber, G. C.; Barbier, C. N.; Cambell, I. H.; Moon, R. L.; Pesavento, P. V.; Fredd, E.; Greenough, N.; Kung, C.

    2014-10-01

    High power RF testing is underway to evaluate transmission line components for the ITER Ion Cyclotron Heating and Current Drive System. The transmission line has a characteristic impedance Z0 = 50 Ω and a nominal outer diameter of 305 mm. It is specified to carry up to 6 MW at VSWR = 1.5 for 3600 s pulses, with transient voltages up to 40 kV. The transmission line is actively cooled, with turbulent gas flow (N2) used to transfer heat from the inner to outer conductor, which is water cooled. High voltage and high current testing of components has been performed using resonant lines generating steady state voltages of 35 kV and transient voltages up to 60 kV. A resonant ring, which has operated with circulating power of 6 MW for 1 hr pulses, is being used to test high power, low VSWR operation. Components tested to date include gas barriers, straight sections of various lengths, and 90 degree elbows. Designs tested include gas barriers fabricated from quartz and aluminum nitride, and transmission lines with quartz and alumina inner conductor supports. The latest results will be presented. This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy.

  10. Automatic Voltage Control (AVC) of Danish Transmission System - Concept design

    DEFF Research Database (Denmark)

    Qin, Nan; Abildgaard, Hans; Lund, P.

    2014-01-01

    , objectives, constraints, algorithms for optimal power flow and some special functions in particular systems, which inspires the concept design of a Danish AVC system to address the future challenges of voltage control. In the concept, the Danish AVC design is based on a centralized control scheme. All....... Another consequence is the public way of generally thinking green which have led to a national decision of undergrounding not only all of the Danish distribution system but also the future transmission system. These issues initiate the infrastructure constructions of the transmission system i.e. a large...... the substation loses the telecommunications to the control center. RPCs will be integrated to the AVC system as normative regulators in the later stage. Distributed generation units can be organized as virtual power plants and participate in voltage control at transmission level. Energinet.dk as the Danish TSO...

  11. A linear signal transmission system calibration method of wideband GPR

    Science.gov (United States)

    Wu, Bin; Zhao, Kai; Gu, Ling-jia; Cao, Qiong; Li, Xiao-feng; Zheng, Xing-ming

    2016-09-01

    In VHF pulse Ground Penetrating Radar(GPR) system, the echo pass through the antenna and transmission line circuit, then reach the GPR receiver. Thus the reflection coefficient at the receiver sampling gate interface, which is at the end of the transmission line, is different from the real reflection coefficient of the media at the antenna interface, which could cause the GPR receiving error. The pulse GPR receiver is a wideband system that can't be simply described as traditional narrowband transmission line model. Since the GPR transmission circuit is a linear system, the linear transformation method could be used to analyze the characteristic of the GPR receiving system. A GPR receiver calibration method based on transmission line theory is proposed in this paper, which analyzes the relationship between the reflection coefficients of theory calculation at antenna interface and the measuring data by network analyzer at the sampling gate interface. Then the least square method is introduced to calibrate the transfer function of the GPR receiver transmission circuit. This calibration method can be useful in media quantitative inversion by GPR. When the reflection coefficient at the sampling gate is obtained, the real reflection coefficient of the media at the antenna interface can be easily determined.

  12. Optimal Transmission Power in a Nonlinear VLC System

    Institute of Scientific and Technical Information of China (English)

    ZHAO Shuang; CAI Sunzeng; KANG Kai; QIAN Hua

    2016-01-01

    In a visible light communication (VLC) system, the light emitting diode (LED) is nonlinear for large signals, which limits the trans⁃mission power or equivalently the coverage of the VLC system. When the input signal amplitude is large, the nonlinear distortion creates harmonic and intermodulation distortion, which degrades the transmission error vector magnitude (EVM). To evaluate the impact of nonlinearity on system performance, the signal to noise and distortion ratio (SNDR) is applied, defined as the linear sig⁃nal power over the thermal noise plus the front end nonlinear distortion. At a given noise level, the optimal system performance can be achieved by maximizing the SNDR, which results in high transmission rate or long transmission range for the VLC system. In this paper, we provide theoretical analysis on the optimization of SNDR with a nonlinear Hammerstein model of LED. Simula⁃tion results and lab experiments validate the theoretical analysis.

  13. Engineering Design of the ITER AC/DC Power Supply System

    Energy Technology Data Exchange (ETDEWEB)

    Oh, B. H.; Lee, K. W.; Chang, D. S.; Jin, J. T.; Hwang, C. K.

    2010-02-15

    To design high power pulse power supplies, especially in huge power supplies have not designed till now, it is necessary to analyze a system's characteristics and relations with another systems as well as to know high voltage, high current control technologies. Contents of this project are; - Analysis of the changed designs of the AC/DC converters. - Setup of the PSIM model for the calculation of the junction temperature of the converter thyristors. - Finalize the converter's simulation modules and estimate the parallel number of an arm for each converter. - Fix the protection sequence and make a simulation. - Stability check of the power distribution system against the reactive power effect. - Design of small size hardware AC/DC converter. The results of these studies may used as one of references for practical designs of the power supplies and also used for developing Tokamak type fusion reactors in the future

  14. Final design of the Korean AC/DC converters for the ITER coil power supply system

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Jong-Seok, E-mail: jsoh@nfri.re.kr [ITER Korea, National Fusion Research Institute, Daejeon 305-806 (Korea, Republic of); Choi, Jungwan; Suh, Jae-Hak; Choi, Jihyun [ITER Korea, National Fusion Research Institute, Daejeon 305-806 (Korea, Republic of); Lee, Lacksang; Kim, Changwoo; Park, Hyungjin; Jo, Seongman; Lee, Seungyun; Hwang, Kwangcheol; Liu, Hyoyol [Dawonsys Corp., Siheung 429-450 (Korea, Republic of); Hong, Ki-Don; Sim, Dong-Joon; Lee, Jang-Soo [Hyosung Corp., Gongdeok-Dong, Seoul 121-720 (Korea, Republic of); Lee, Eui-Jae; Kwon, Yang-Hae; Lee, Dae-Yeol; Ko, Ki-Won; Kim, Jong-Min [Mobiis Corp., Yangjae-dong, Seoul 137-888 (Korea, Republic of); Song, Inho [ITER Organization, Route de Vinon sur Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); and others

    2015-10-15

    The final design of the ITER TF, CS, CC and VS AC/DC converters has been completed to implement ITER requirements following the detailed design and refinements of the preliminary design. The number of parallel thyristors and the rating of fuses are coordinated to keep those devices within the explosion limit even under most severe fault conditions. The impedance of the converter transformer has been optimized taking into account the energization inrush current, short circuit current, reactive power consumption and the available DC voltage. To ensure system integrity, AC/DC converters are mechanically divided into transformers, AC busbars, 6-pulse bridges, DC interconnecting busbars and DC reactors, and then all subsystems are decoupled by flexible links. To provide stable real time network communication down to the converters, a one GbE link is deployed between master controllers and local controllers. IEEE 1588 is implemented to the embedded controllers for precision time synchronization. This paper describes the detailed solutions implemented in the final design for the ITER AC/DC converters with R&D results of converter prototypes.

  15. Design of UAV high resolution image transmission system

    Science.gov (United States)

    Gao, Qiang; Ji, Ming; Pang, Lan; Jiang, Wen-tao; Fan, Pengcheng; Zhang, Xingcheng

    2017-02-01

    In order to solve the problem of the bandwidth limitation of the image transmission system on UAV, a scheme with image compression technology for mini UAV is proposed, based on the requirements of High-definition image transmission system of UAV. The video codec standard H.264 coding module and key technology was analyzed and studied for UAV area video communication. Based on the research of high-resolution image encoding and decoding technique and wireless transmit method, The high-resolution image transmission system was designed on architecture of Android and video codec chip; the constructed system was confirmed by experimentation in laboratory, the bit-rate could be controlled easily, QoS is stable, the low latency could meets most applied requirement not only for military use but also for industrial applications.

  16. Tidal current turbine based on hydraulic transmission system

    Institute of Scientific and Technical Information of China (English)

    Hong-wei LIU; Wei LI; Yong-gang LIN; Shun MA

    2011-01-01

    Tidal current turbines (TCTs) are newly developed electricity generating devices.Aiming at the stabilization of the power output of TCTs,this paper introduces the hydraulic transmission technologies into TCTs.The hydrodynamics of the turbine was analyzed at first and its power output characteristics were predicted.A hydraulic power transmission system and a hydraulic pitch-controlled system were designed.Then related simulations were conducted.Finally,a TCT prototype was manufactured and tested in the workshop.The test results have confirmed the correctness of the current design and availability of installation of the hydraulic system in TCTs.

  17. FPGA Implementation of Video Transmission System Based on LTE

    Directory of Open Access Journals (Sweden)

    Lu Yan

    2015-01-01

    Full Text Available In order to support high-definition video transmission, an implementation of video transmission system based on Long Term Evolution is designed. This system is developed on Xilinx Virtex-6 FPGA ML605 Evaluation Board. The paper elaborates the features of baseband link designed in Xilinx ISE and protocol stack designed in Xilinx SDK, and introduces the process of setting up hardware and software platform in Xilinx XPS. According to test, this system consumes less hardware resource and is able to transmit bidirectional video clearly and stably.

  18. Modern Systems of Information Transmission on Agro & Food Supply Chain

    Directory of Open Access Journals (Sweden)

    Silvius STANCIU

    2011-11-01

    Full Text Available Global food commodity diversification requires the application of new methods of data identification, monitoring, collection and processing in the production or distribution area. Classical systems of information transmission are currently widely used, but also present some inconvenience addressed by the emergence of new generations of information carriers. Current requirements for technical processes monitoring, quality assurance, traceability and customer orientation led to the emergence and evolution of modern identification systems based on dynamic information transmission and global databases development. The development of computer technology and the Internet are factors that allowed the development of these systems.

  19. Subcarrier multiplexing tolerant dispersion transmission system employing optical broadband sources.

    Science.gov (United States)

    Grassi, Fulvio; Mora, José; Ortega, Beatriz; Capmany, José

    2009-03-16

    This paper presents a novel SCM optical transmission system for next-generation WDM-PONs combining broadband optical sources and a Mach-Zehnder interferometric structure. The approach leeds to transport RF signals up to 50 GHz being compatible with RoF systems since a second configuration has been proposed in order to overcome dispersion carrier suppression effect using DSB modulation. The theoretical analysis validates the potentiality of the system also considering the effects of the dispersion slope over the transmission window.

  20. Revised bolometric corrections and interstellar extinction coefficients for the ACS and WFPC2 photometric systems

    CERN Document Server

    Girardi, L; Williams, B; de Jong, R; Gallart, C; Monelli, M; Groenewegen, M A T; Holtzman, J A; Olsen, K A G; Seth, A C; Weisz, D R

    2008-01-01

    We present extensive tables of bolometric corrections and interstellar extinction coefficients for the WFPC2 and ACS (both WFC and HRC) photometric systems. They are derived from synthetic photometry applied to a database of spectral energy distributions covering a large range of effective temperatures, surface gravity, and metal content. Carbon stars are also considered. The zero-points take into consideration the new high-accuracy Vega fluxes from Bohlin. These tables are employed to transform Padova isochrones into WFPC2 and ACS photometric systems using interstellar extinction coefficients on a star-to-star basis. All data are available either in tabular form or via an interactive web interface in the case of the isochrones. Preliminary tables for the WFC3 camera are also included in the database.

  1. Mathematical analysis of parameter maintenance in precision technological V and AC systems (rus

    Directory of Open Access Journals (Sweden)

    Sotnikov A.G.

    2011-08-01

    Full Text Available Various industrial processes usually take place in the air and they require different parameters of air quality and accuracy of its maintenance.In present there are no rigorous analytical methods for reliable determination the actual accuracy of maintenance of air quality parameters on condition that they change orderly or stochastically. The harmonic analysis of exponents of periodical increase and decrease of parameters is proposed. It can be used for the estimation of fluctuations and precision of maintenance of various air quality parameters, first of all, in precision technological V and AC systems.Suggested method of temperature calculation under changing periodical heat load at the premises is illustrated by the example of high-precision V and AC system operating the area of grinding and test of optical devices.

  2. Investigation of multimodule buck–boost inverter-based HVDC transmission system

    Directory of Open Access Journals (Sweden)

    Ahmed A. Elserougi

    2015-01-01

    Full Text Available In high voltage direct current (HVDC systems, the semiconductor devices have to be connected in series to obtain the required high-voltage ratings. This study proposes a new HVDC configuration, namely, multimodule buck–boost inverter for HVDC transmission applications which avoids series connection of large number of semiconductor switches. In addition, it provides a blocking capability against DC side faults. The proposed configuration consists of several simple buck–boost converters which are assembled together to meet the requirements of high-voltage high-power applications. This paper studies the dynamic performance of the proposed system under different operating conditions, and the results were satisfactory. The main advantages of the proposed configuration are: (i pure sinusoidal output which minimises/eliminates the requirements for supplementary AC filters and offers an inherent suppression to the common mode voltages, (ii very low dv/dt stresses and (iii complete blocking capability of AC side contributions during DC side faults. This study discusses the system architecture, passive components selections, voltage and current ratings of its semiconductor devices and the required controllers. A comparison between the proposed configuration and other existing HVDC technologies is also presented in this study.

  3. Load flow computations in hybrid transmission - distributed power systems

    NARCIS (Netherlands)

    Wobbes, E.D.; Lahaye, D.J.P.

    2013-01-01

    We interconnect transmission and distribution power systems and perform load flow computations in the hybrid network. In the largest example we managed to build, fifty copies of a distribution network consisting of fifteen nodes is connected to the UCTE study model, resulting in a system consisting

  4. VLBI data transmission system using multiple IP streams

    Science.gov (United States)

    Uose, Hisao

    We have developed an IP-based data transmission system which can directly replace K4 (ID1) VLBI data recorder. It employs multiple TCP data steams and individual buffers to cope with variable usable bandwidth we encouter when we use shared academic networks. This paper describes the outline of the system and preliminary testing results.

  5. Technology for extending transmission distance of EPON system

    Institute of Scientific and Technical Information of China (English)

    Li ZHANG; Deming LIU; Cbuanbao ZHANG; Guangsbeng WU

    2009-01-01

    At present, the maximal transmission distance between the optical line terminal (OLT) and opticalnetwork unit (ONU) of an Ethemet passive optical network (EPON) system is 20 km.However, this distance should be extended to 50 km or even longer in some applications such as fiber to the village (FTTV).A method for extending the transmission distance of an EPON system is proposed in this paper, in which the optical power amplifier and the adjustment of dynamic bandwidth allocation (DBA) are the key technologies.

  6. Stokes Space in Direct-Detection Data Transmission Systems

    DEFF Research Database (Denmark)

    Estaran Tolosa, Jose Manuel; Lu, Xiaofeng; Zibar, Darko;

    2015-01-01

    Stokes-based processing permits complete and phase-insensitive characterization of the field’s SOP, readily unlocking polarization diversity in transmission systems where DD is desired. We present an overview on Stokes notions and most recent achievements in this context.......Stokes-based processing permits complete and phase-insensitive characterization of the field’s SOP, readily unlocking polarization diversity in transmission systems where DD is desired. We present an overview on Stokes notions and most recent achievements in this context....

  7. Coordinated Secondary Control for Balanced Discharge Rate of Energy Storage System in Islanded AC Microgrids

    DEFF Research Database (Denmark)

    Guan, Yajuan; Quintero, Juan Carlos Vasquez; Guerrero, Josep M.

    2016-01-01

    incidents and unintentional outages in DG units, but also aims to provide a fast transient response and an accurate output-current-sharing performance. A complete root locus analysis is given in order to achieve system stability and parameter sensitivity. Experimental results are presented to show......A coordinated secondary control approach based on an autonomous current-sharing control strategy for balancing the discharge rates of energy storage systems (ESSs) in islanded AC microgrids is proposed in this paper. The coordinated secondary controller can regulate the power outputs of distributed...... the performance of the whole system and to verify the effectiveness of the proposed controller....

  8. Real-Time Energy Management System for a Hybrid AC/DC Residential Microgrid

    DEFF Research Database (Denmark)

    Diaz, Enrique Rodriguez; Palacios-Garcia, Emilio J.; Anvari-Moghaddam, Amjad

    2017-01-01

    /discharge of the ESS, and the energy injection/consumption from the grid. The EMS estimates the RES generation based on the weather forecasting, together with stochastic consumption modelling of the building. The EMS architecture and the residential microgrid have been implemented and tested in a laboratory scale......) and the building’s common facilities; while the apartments are supplied by an ac distribution system connected to the grid. This architecture avoids any modifications in the electrical installation that supplies energy to the apartments. A pure dc voltage supply is not yet a feasible approach for residential...... buildings. This architecture increases the overall efficiency of the distribution by interconnecting the RES and ESS thorough a dc distribution bus, and therefore avoiding unnecessary dc/ac conversion stages. The real-time EMS performs an 24 hours ahead optimization in order to schedule the charge...

  9. Development and test of the ASAT Bipropellant Attitude Control System (ACS) engine

    Science.gov (United States)

    Hodge, K. F.; Allen, K. A.; Hemmings, B.

    1993-06-01

    The recent Kinetic Energy Anti-Satellite (KE ASAT) Bipropellant Attitude Control System (ACS) Engine testing demonstrated and characterized performance and operational durability. Within the ASAT mission, the bipropellant engines are used to despin the missile after shroud deployment and to provide attitude control of the Kill Vehicle (KV) during all phases of the KV free flight. These engines provide all attitude control thrust from booster separation until target intercept. The ASAT ACS engine is unique both in the amount of on-time that the engine sees during a tactical mission scenario and the high thermal loads which result from performing two diametrically opposed missions with a single thruster - long steady state burns and very short response time pulse mode operations. Two flightweight ASAT ACS Bipropellant engines were individually tested in a developmental test program. Testing was conducted at ambient conditions. Hot-fire testing consisted of steady-state, mission duty cycle (MDC), Chamber Pressure (Pc) excursion, mixture ratio excursion, and pulse performance. Testing was conducted by Rockwell's Rocketdyne Division at the Santa Susana Field Laboratory (SSFL), Systems Test Laboratory IV (STL IV), Cell 37A. Two additional engine tests are planned and will include altitude testing. This paper will summarize engine development, component development testing, valve orificing and cold flow calibration, and engine hot-fire testing approach and results.

  10. HVDC transmission power conversion applications in power systems

    CERN Document Server

    Kim, Chan-Ki; Jang, Gil-Soo; Lim, Seong-Joo; Lee, Seok-Jin

    2009-01-01

    HVDC is a critical solution to several major problems encountered when trying to maintain systemic links and quality in large-scale renewable energy environments. HDVC can resolve a number of issues, including voltage stability of AC power networks, reducing fault current, and optimal management of electric power, ensuring the technology will play an increasingly important role in the electric power industry. To address the pressing need for an up-to-date and comprehensive treatment of the subject, Kim, Sood, Jang, Lim and Lee have collaborated to produce this key text and reference.  Combin

  11. Power Transmission System Vulnerability Assessment Using Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    E. Karimi

    2012-11-01

    Full Text Available Recent blackouts in power systems have shown the necessity of vulnerability assessment. Among all factors, transmission system components have a more important role. Power system vulnerability assessment could capture cascading outages which result in large blackouts and is an effective tool for power system engineers for defining power system bottlenecks and weak points. In this paper a new method based on fault chains concept is developed which uses new measures. Genetic algorithm with an effective structure is used for finding vulnerable branches in a practical power transmission system. Analytic hierarchy process is a technique used to determine the weighting factors in fitness function of genetic algorithm. Finally, the numerical results for Isfahan Regional Electric Company are presented which verifies the effectiveness and precision of the proposed method according to the practical expriments.

  12. A New Design of Video Streaming Capture and Transmission System

    Directory of Open Access Journals (Sweden)

    Xingyu Geng

    2014-10-01

    Full Text Available Aiming to solve some existing problems such as low video streaming rate, high cost and complex set-up, a new video streaming capture and transmission system based on servfox is proposed. This system uses servfox to invoke V4L APIs to capture video streaming in Linux operating system, and then transmits the data to a remote monitoring client through Internet which can display the video streaming. Remote client can be either a software or a web browser. The experimental results show that the image captured by this system is high-quality and the streaming rate is high. At the same time, the system possesses high reliability and low cost. Compared with existing methods, this system can be widely used in the process of video streaming capture and transmission

  13. Reliability Analysis of Random Vibration Transmission Path Systems

    Directory of Open Access Journals (Sweden)

    Wei Zhao

    2017-01-01

    Full Text Available The vibration transmission path systems are generally composed of the vibration source, the vibration transfer path, and the vibration receiving structure. The transfer path is the medium of the vibration transmission. Moreover, the randomness of transfer path influences the transfer reliability greatly. In this paper, based on the matrix calculus, the generalized second moment technique, and the stochastic finite element theory, the effective approach for the transfer reliability of vibration transfer path systems was provided. The transfer reliability of vibration transfer path system with uncertain path parameters including path mass and path stiffness was analyzed theoretically and computed numerically, and the correlated mathematical expressions were derived. Thus, it provides the theoretical foundation for the dynamic design of vibration systems in practical project, so that most random path parameters can be considered to solve the random problems for vibration transfer path systems, which can avoid the system resonance failure.

  14. Medical data transmission system for remote healthcare centres

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, E A; Cagnolo, F J; Olmos, C E; Centeno, C A; Riva, G G; Zerbini, C A [Clinical Engineering Group, National Technological University, Cordoba Regional Faculty, Maestro M Lopez St and Cruz Roja Argentina St, Cordoba (Argentina)

    2007-11-15

    The main motivation of this project is to improve the healthcare centres equipment and human resources efficiency, enabling those centres for transmission of parameters of medical interest. This system facilitates remote consultation, in particular between specialists and remote healthcare centres. Likewise it contributes to the qualification of professionals. The electrocardiographic (ECG) and electroencephalographic (EEG) signals are acquired, processed and then sent, fulfilling the effective norms, for application in the hospital network of Cordoba Province, which has nodes interconnected by phone line. As innovative aspects we emphasized the low cost of development and maintenance, great versatility and handling simplicity with a modular design for interconnection with diverse data transmission media (Wi-Fi, GPRS, etc.). Successfully experiences were obtained during the acquisition of the signals and transmissions on wired LAN networks. As improvements, we can mention: energy consumption optimization and mobile communication systems usage, in order to offer more autonomy.

  15. Impedance matching wireless power transmission system for biomedical devices.

    Science.gov (United States)

    Lum, Kin Yun; Lindén, Maria; Tan, Tian Swee

    2015-01-01

    For medical application, the efficiency and transmission distance of the wireless power transfer (WPT) are always the main concern. Research has been showing that the impedance matching is one of the critical factors for dealing with the problem. However, there is not much work performed taking both the source and load sides into consideration. Both sides matching is crucial in achieving an optimum overall performance, and the present work proposes a circuit model analysis for design and implementation. The proposed technique was validated against experiment and software simulation. Result was showing an improvement in transmission distance up to 6 times, and efficiency at this transmission distance had been improved up to 7 times as compared to the impedance mismatch system. The system had demonstrated a near-constant transfer efficiency for an operating range of 2cm-12cm.

  16. Different Types of Coding Input Data In Optical Transmission Systems

    Directory of Open Access Journals (Sweden)

    Ján Ružbarský

    2016-12-01

    Full Text Available Optical fiber transmission systems are currently the most widely used transmission media. Their development in time had improved their characteristics to such an extent that they gradually replaced very popular copper cable connections. Inspite of that optical fibers still have not reached perfection and constant improvement is needed. Apart from notable advantages such as large data transfer, few numbers of repeaters required on the transmission path or higher safety of transmitted data, optical fiber has also drawbacks that include not sufficient purity optical fibers, fiber fragility and also higher proclivity to nonlinear effects. Weaknesses of optical systems can be depressed by e.g. a selection of an appropriate laser, a proper combination of materials used for fiber production during the manufacture process, or even by using an encryption of transmitted data. This article is focused on the comparison of optical signal properties in various source encoding types of input data.

  17. Model for the ready definition and approximate comparison of alternative high voltage transmission systems

    Energy Technology Data Exchange (ETDEWEB)

    1978-12-01

    A model of generic overhead transmission systems in the range of 362 to 1200 kV ac, and +-400 to +-800 kV dc is developed. Such generic systems are to include (a) transmission from generation to load, and (b) interconnection of two large integrated systems, with and without the existence of an underlying, lower voltage network in either case. The model provides a means whereby an engineer with some experience in power systems planning can make a reconnaissance study of alternatives within a relatively short span of time and with fair accuracy. Given an amount of power to be transferred over a specified distance, the model can be used: to define the workable alternatives in terms of voltages, number of lines, series compensation, and certain other factors affecting transfer capability; to delineate other salient features of the selected alternatives, notably shunt compensation requirements; and to compare the alternatives in terms of potentially relevant benefits and costs. The significant properties of the model, the basis and assumptions necessary to its formulation, instructions for its use, and inherent limitations upon the accuracy to be expected are described.

  18. Guidelines for transient analysis in water transmission and distribution systems

    OpenAIRE

    Pothof, Ivo; Karney, Bryan

    2012-01-01

    All water systems leak, and many supply systems do so considerably, with water losses typically of approximately 20% of the water production. The IWA Water Loss Task Force aims for a significant reduction of annual water losses by drafting documents to assist practitioners and others to prevent, monitor and mitigate water losses in water transmission and distribution systems. One of the causes of water losses are transient phenomena, caused by normal and accidental pump and valve operations. ...

  19. Adaptive Neurofuzzy Inference System-Based Pollution Severity Prediction of Polymeric Insulators in Power Transmission Lines

    Directory of Open Access Journals (Sweden)

    C. Muniraj

    2011-01-01

    Full Text Available This paper presents the prediction of pollution severity of the polymeric insulators used in power transmission lines using adaptive neurofuzzy inference system (ANFIS model. In this work, laboratory-based pollution performance tests were carried out on 11 kV silicone rubber polymeric insulator under AC voltage at different pollution levels with sodium chloride as a contaminant. Leakage current was measured during the laboratory tests. Time domain and frequency domain characteristics of leakage current, such as mean value, maximum value, standard deviation, and total harmonics distortion (THD, have been extracted, which jointly describe the pollution severity of the polymeric insulator surface. Leakage current characteristics are used as the inputs of ANFIS model. The pollution severity index “equivalent salt deposit density” (ESDD is used as the output of the proposed model. Results of the research can give sufficient prewarning time before pollution flashover and help in the condition based maintenance (CBM chart preparation.

  20. Advanced coding techniques for few mode transmission systems.

    Science.gov (United States)

    Okonkwo, Chigo; van Uden, Roy; Chen, Haoshuo; de Waardt, Huug; Koonen, Ton

    2015-01-26

    We experimentally verify the advantage of employing advanced coding schemes such as space-time coding and 4 dimensional modulation formats to enhance the transmission performance of a 3-mode transmission system. The performance gain of space-time block codes for extending the optical signal-to-noise ratio tolerance in multiple-input multiple-output optical coherent spatial division multiplexing transmission systems with respect to single-mode transmission performance are evaluated. By exploiting the spatial diversity that few-mode-fibers offer, with respect to single mode fiber back-to-back performance, significant OSNR gains of 3.2, 4.1, 4.9, and 6.8 dB at the hard-decision forward error correcting limit are demonstrated for DP-QPSK 8, 16 and 32 QAM, respectively. Furthermore, by employing 4D constellations, 6 × 28Gbaud 128 set partitioned quadrature amplitude modulation is shown to outperform conventional 8 QAM transmission performance, whilst carrying an additional 0.5 bit/symbol.

  1. An overview of power electronics applications in fuel cell systems: DC and AC converters.

    Science.gov (United States)

    Ali, M S; Kamarudin, S K; Masdar, M S; Mohamed, A

    2014-01-01

    Power electronics and fuel cell technologies play an important role in the field of renewable energy. The demand for fuel cells will increase as fuel cells become the main power source for portable applications. In this application, a high-efficiency converter is an essential requirement and a key parameter of the overall system. This is because the size, cost, efficiency, and reliability of the overall system for portable applications primarily depend on the converter. Therefore, the selection of an appropriate converter topology is an important and fundamental aspect of designing a fuel cell system for portable applications as the converter alone plays a major role in determining the overall performance of the system. This paper presents a review of power electronics applications in fuel cell systems, which include various topology combinations of DC converters and AC inverters and which are primarily used in fuel cell systems for portable or stand-alone applications. This paper also reviews the switching techniques used in power conditioning for fuel cell systems. Finally, this paper addresses the current problem encountered with DC converters and AC inverter.

  2. Control strategies for VSC-based HVDC transmission system

    DEFF Research Database (Denmark)

    Stan, Ana-Irina; Stroe, Daniel Ioan; Silva, Rodrigo Da

    2011-01-01

    the behavior of the developed VSC-based HVDC transmission system two study cases are carried out using MATLAB/Simulink. The results obtained from simulations show acceptable performances, of the proposed strategies, when changes in the reference parameters are considered. The active power flow between...

  3. A CONTACTLESS TRANSMITTER FOR THE M TYPE DATA TRANSMISSION SYSTEM.

    Science.gov (United States)

    A contactless transmitter employing electromagnetic principles for the M type data transmission system is described. It could be contained in a size 11 standard housing if the six semiconductor main switches are mounted externally. Tests showed that the transmitter will operate satisfactorily at speeds in excess of 3000 rev/min, and that it could form the basis of a brushless dc motor . (Author)

  4. Transpositional behaviour of the Ds element in the Ac/Ds system in rice

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Insertional mutagenesis based on maize Activator/Dissociator (Ac/Ds) transposons is becoming a major approach used to produce a saturated mutant collection in rice. In this research, Ds-T-DNA transformed homozygotes were crossed with Ac-T-DNA transformed homozygotes in order to establish an Ac/Ds transposon system in rice. The successive investigation of Ds transposition from F1 to F5 generations indicated that the frequencies of germinal transposition increased over successive generations and reached 54.2% in F3 generation. The Ds transposition pattern revealed that a Ds transposition induced an approximately 170-bp deletion of T-DNA sequence and another Ds transposition carried a 272-bp T-DNA sequence. Using thermal asymmetric interlaced PCR (TAIL-PCR), some flanking sequences of the Ds element were amplified. Analyses of 17 Ds-flanking sequences showed that five Ds were inserted into gene regions. The Ds could transpose not only to the linked sites but also to the unlinked sites. The frequency of inter-chromosomal transposition of Ds was 33.3%.

  5. Equalization Algorithm for Distributed Energy Storage Systems in Islanded AC Microgrids

    DEFF Research Database (Denmark)

    Aldana, Nelson Leonardo Diaz; Hernández, Adriana Carolina Luna; Quintero, Juan Carlos Vasquez

    2015-01-01

    This paper presents a centralized strategy for equalizing the state of charge of distributed energy storage systems in an islanded ac microgrid. The strategy is based on a simple algorithm denoted as equalization algorithm, which modifies the charge or discharge ratio on the time, for distributed...... energy storage systems, within a determined period of time in order to equalize the state of charge. The proposed approach has been tested in a MATLAB/Simulink model of the microgrid where the performance of the proposed strategy was verified....

  6. Spin superconductivity and ac-Josephson effect in Graphene system under strong magnetic field

    Science.gov (United States)

    Liu, Haiwen; Jiang, Hua; Sun, Qing-Feng; Xie, X. C.; Collaborative Innovation Center of Quantum Matter, Beijing, China Collaboration

    We study the spin superconductivity in Graphene system under strong magnetic field. From the microscopically Gor'kov method combined with the Aharonov-Casher effect, we derive the effective Landau-Ginzburg free energy and analyze the time evolution of order parameter, which is confirmed to be the off-diagonal long range order. Meanwhile, we compare the ground state of spin superconductivity to the canted-antiferromagnetic state, and demonstrate the equivalence between these two states. Moreover, we give out the pseudo-field flux quantization condition of spin supercurrent, and propose an experimental measurable ac-Josephson effect of spin superconductivity in this system.

  7. A development of ITV system for power transmission line monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Hong Keun; Kim, Seok Ku; Lee, Kwang Joong; Lee, Won Bin [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center

    1995-12-31

    Transmission lines which are important to supply the electricity installed on the terrestrially severe site such as mountains needed to be monitored to prevent electric fault by snow accelerating, icing, tree contact, fire etc. Inspections by human patrol has been done but it seems not so efficient and satisfiable. To cope with this a transmission line monitoring system using industrial television and OPGW was developed and field trilled at the site. This paper describes about the optical video transceiver, video distributor and control devices (author).

  8. Shot noise in nano-electronic systems under the perturbation of ac fields

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hong-kang

    2007-01-01

    Current noise exists in circuits and electronic devices generally, and it exhibits specific features as the system reaches nanometer size. The noise in the nano-system where external ac fields are applied plays an important role, since the properties of the fields and the nano-system together govern the resulting noise. In this paper, we present the derivation of shot noise by employing the nonequilibrium Green's function technique. The more general formulas for the current correlation and noise spectral density are given. The system is composed of a central nanosystem coupled to electrodes, and the obtained noise formulas are related to the Green's functions of detailed central regime and the terminals. As an example, we have performed the numerical calculation on a system with a toroidal carbon nanotube coupled to normal metal leads. The noise and Fano factor show intimate relation with the structure of the system and ac fields. The Aharonov-Bohm-like behaviors on the shot noise spectral density and Fano factor are observed to exhibit oscillation structures with period of quantum flux.

  9. Comparison of the Accuracy and Speed of Transient Mobile A/C System Simulation Models: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Kiss, T.; Lustbader, J.

    2014-03-01

    The operation of air conditioning (A/C) systems is a significant contributor to the total amount of fuel used by light- and heavy-duty vehicles. Therefore, continued improvement of the efficiency of these mobile A/C systems is important. Numerical simulation has been used to reduce the system development time and to improve the electronic controls, but numerical models that include highly detailed physics run slower than desired for carrying out vehicle-focused drive cycle-based system optimization. Therefore, faster models are needed even if some accuracy is sacrificed. In this study, a validated model with highly detailed physics, the 'Fully-Detailed' model, and two models with different levels of simplification, the 'Quasi-Transient' and the 'Mapped- Component' models, are compared. The Quasi-Transient model applies some simplifications compared to the Fully-Detailed model to allow faster model execution speeds. The Mapped-Component model is similar to the Quasi-Transient model except instead of detailed flow and heat transfer calculations in the heat exchangers, it uses lookup tables created with the Quasi-Transient model. All three models are set up to represent the same physical A/C system and the same electronic controls. Speed and results of the three model versions are compared for steady state and transient operation. Steady state simulated data are also compared to measured data. The results show that the Quasi-Transient and Mapped-Component models ran much faster than the Fully-Detailed model, on the order of 10- and 100-fold, respectively. They also adequately approach the results of the Fully-Detailed model for steady-state operation, and for drive cycle-based efficiency predictions

  10. Life Cycle Assessment on a 765 kV Venezuelan Transmission System

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wenlu; Tremouille, Gilles [Alstom Grid (France); Beroual, Abderrahmane [Ecole Centrale de Lyon (France); Bessede, Jean-Luc [Schneider Electric Energy (France)

    2011-03-15

    The demand to preserve the environment and form a sustainable development is greatly increasing in the recent decades all over the world, and this environmental concern is also merged in electrical power industry, resulting in many eco-design approaches in T and D industries. As a method of eco-design, Life Cycle Assessment (LCA) is a systematic tool that enables the assessment of the environmental impacts of a product or service throughout its entire life cycle, i.e. raw material production, manufacture, distribution, use and disposal including all intervening transportation steps necessary or caused by the product's existence. In T and D industries, LCA has been done for a lot of products individually, in order to see one product's environmental impacts and to seek for ways of improving its environmental performance. This eco-design for product approach is a rather well-developed trend, however, as only a single electrical product cannot provide the electrical power to users, electrical system consists of a huge number of components, in order to investigate system's environmental profile, the entire environmental profiles of different composing products has to be integrated systematically, that is to say, a system approach is needed. Under this philosophy, in this paper, an LCA using SimaPro (one kind of LCA software) is conducted on a whole Venezuelan 765 kV AC transmission system, which transmits 8000 MW hydro-electrical power through 760 km to this country's load centers, with total 7 substations, i.e. one sending end, 2 intermediate substations and 4 receiving ends. This LCA includes both transmission lines and substations, and then the environmental impacts of the whole transmission system are investigated. (authors)

  11. Selective transmission and channel estimation in massive MIMO systems

    Institute of Scientific and Technical Information of China (English)

    杨睿哲

    2016-01-01

    Massive MIMO systems have got extraordinary spectral efficiency using a large number of base station antennas, but it is in the challenge of pilot contamination using the aligned pilots.To address this issue, a selective transmission is proposed using time-shifted pilots with cell grouping, where the strong interfering users in downlink transmission cells are temporally stopped during the pilots transmission in uplink cells.Based on the spatial characteristics of physical channel models, the strong interfering users are selected to minimize the inter-cell interference and the cell grouping is designed to have less temporally stopped users within a smaller area.Furthermore, a Kalman estima-tor is proposed to reduce the unexpected effect of residual interferences in channel estimation, which exploits both the spatial-time correlation of channels and the share of the interference information. The numerical results show that our scheme significantly improves the channel estimation accuracy and the data rates.

  12. Fast isolation of faults in transmission systems using current transients

    Energy Technology Data Exchange (ETDEWEB)

    Perera, N.; Rajapakse, A.D. [University of Manitoba, Department of Electrical and Computer Engineering, Engineering Building, 15 Gillson Street, Winnipeg, Manitoba (Canada)

    2008-09-15

    This paper presents a protection scheme that is capable of very fast isolation of faults in high voltage transmission systems. Proposed scheme comprises set of relays connected through a telecommunication network, located at different nodes of the system. Relays use wavelet coefficients of current signals to identify the fault directions relative to their location. Fault directions identified at different locations in the system can be combined to determine the faulted line (or busbar) and isolate it. A robust single ended traveling wave based fault distance estimation approach is proposed as a backup in case of communication failure. Investigations were carried out using time domain simulations in PSCAD/EMTDC for a high voltage transmission system. (author)

  13. Quantum system driven by incoherent a.c fields: Multi-crossing Landau Zener dynamics

    Science.gov (United States)

    Jipdi, M. N.; Fai, L. C.; Tchoffo, M.

    2016-10-01

    The paper investigates the multi-crossing dynamics of a Landau-Zener (LZ) system driven by two sinusoidal a.c fields applying the Dynamic Matrix approach (DMA). The system is shown to follow one-crossing and multi-crossing dynamics for low and high frequency regime respectively. It is shown that in low frequency regime, the resonance phenomenon occurs and leads to the decoupling of basis states; the effective gap vanishes and then the complete blockage of the system. For high frequency, the system achieves multi-crossing dynamics with two fictitious crossings; the system models a Landau-Zener-Stückelberg (LZS) interferometer with critical parameters that tailor probabilities. The system is then shown to depend only on the phase that permits the easiest control with possible application in implementing logic gates.

  14. Characterization and evaluation of a handheld AC-coupled pulsed photothermal radiometry system

    Science.gov (United States)

    Jung, Byungjo; Kim, Chang-Seok; Choi, Bernard; Nelson, J. Stuart

    2006-02-01

    In laser therapy of port wine stain (PWS) birthmarks, measurement of maximum temperature rise is important to determine the maximum permissible light dose for PWS laser therapy. To measure maximum temperature rise on arbitrary PWS skin site, we developed a handheld pulsed photothermal radiometry (PPTR) system, which overcomes in vivo measurement limitations of bench-top PPTR systems. The developed PPTR system consists of an IR lens, an AC-coupled thermoelectrically cooled IR detector, a laser handpiece holder, and a fixed distance measurement port. With system characterization, experimental results were in good agreement with theoretical calculations. Preliminary results for maximum temperature rise demonstrate the feasibility of the PPTR system for PWS skin characterization in the clinic.

  15. Productive efficiency in electricity transmission and distribution systems

    Energy Technology Data Exchange (ETDEWEB)

    Pollitt, M.G. [Oxford Univ. (United Kingdom)

    1994-09-01

    This paper presents a Data Envelopment Analysis (DEA) and an OLS analysis of productive efficiency (cost efficiency) in 129 electricity transmission and 145 electricity distribution systems operating in the accounting year 1990. The transmission data contains US electric systems while the distribution data includes 136 US and 9 UK companies. The paper tests the null hypothesis that privately owned and publicly owned electricity systems do not have significantly different costs. The results of the analysis indicate two things: firstly, a strong inability to reject the null hypothesis in favour of the alternative hypothesis that privately owned firms are more efficient; and secondly, a relatively high level of technical efficiency within the UK companies in the year immediately prior to privatisation. (author)

  16. Component development for the ITER Ion Cyclotron Heating and Current Drive Transmission Line and Matching System

    Science.gov (United States)

    Goulding, R. H.; McCarthy, M. P.; Rasmussen, D. A.; Swain, D. W.; Barber, G. C.; Barbier, C. N.; Cambell, I. H.; Gray, S. L.; Moon, R. L.; Pesavento, P. V.; Sanabria, R. M.; Fredd, E.; Greenough, N.

    2013-10-01

    The transmission line and matching network for the ITER Ion Cyclotron Heating and Current Drive System feeds two equatorial launchers, each with 24 phased current straps combined into groups of three, and each designed to couple up to 20 MW into ELMy H-mode plasmas in the frequency range 40-55 MHz, for pulse lengths up to 3600 s. The network includes > 1 km of 50 Ohm 300 mm diameter transmission line carrying up to 6 MW net power per line at VSWR = 1.5. In addition, there are 8 power splitters, 32 hybrid phase shifters incorporating 64 tuning stubs, 32 additional tuning stubs, and 36 vacuum capacitors, which are configured to provide pre-matching in the port cell region adjacent to the antenna, final matching, decoupling of mutual inductances between antenna elements, and passive ELM resilience. The development and design of the various system components will be discussed. High power tests of components have begun, and the latest results will be presented. This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy.

  17. 带弧垂特高压交流输电线路的电磁剂量学分析%Analysis of electromagnetic dosimetry by ultra high voltage AC transmission line with belt sag

    Institute of Scientific and Technical Information of China (English)

    张利航; 逯迈; 陈小强; 侯立伟

    2016-01-01

    采用Comsol仿真软件和人体模型计算分析倒三角较贴近实际的带弧垂特高压交流输电线路对人体产生的电场效应,并与理想直导线的结果进行对比。结果表明,人体以及人体附近电场和感应电流分布不均匀,体外电场最大值集中于人体头部表面上方,关节连接处和端部的电场、感应电流密度较大。带弧垂特高压输电线路在人体各组织产生的电场和感应电流密度均较理想笔直导线线路下高约17%~19%;与国际非电离辐射防护委员会(International commission on non-ionizing radiation protection, ICNIRP)导则限值相比较,电场强度无论是对专业人员还是普通民众均在 ICNIRP 导则限值范围内;而感应电流密度除人体腿部下部、头皮与颈部连接处附近的略高于ICNIRP导则中普通民众的限值外,其他均在ICNIRP导则限值范围内。两种类型特高压输电线路所产生的电磁辐射对专业人员是安全的,对普通民众应注意适当的防护。%The aim is to investigate the electric field effect produced by the ultra high voltage (UHV) AC transmission lines with belt sag on the human body. A simulation software named Comsol and a human body model were used to calculate and analyze the electric field effect caused by the nabla UHV AC transmission lines closely to the reality, and then the result was compared with the one produced by ideal straight lines. The results indicated that in the human and the near-field region, the distribution of electric field and induced current was nonuniform. The maximum electric field focused on the above region of human head surface. The value of electric field intensity and  induced current density in the joints of the body were high. Below the actual and ideal straight UHV transmission lines, the electric field intensity and induced current density produced by the belt sag wire in all tissues including central nervous system of human was 17

  18. Transmission dispatch and congestion management in open market systems

    Science.gov (United States)

    Fang, Risheng

    This thesis is located in the domain of electricity supply industry restructuring. It deals with emerging issues, whose understanding is essential to advancing knowledge of open access transmission theory and proceeds to develop approaches for solving the transmission dispatch and congestion management problem. An overview of current trends and experiences in utility restructuring and the main models for restructuring, as well as the classifications of system operators, is first presented. A fully unbundled competitive electricity market model, called the bilateral/multilateral trades model, is then developed. A survey of current research in transmission dispatch and congestion management is included with discussion of transmission capacity and ancillary services. A methodology for the power dispatch problem in a structure dominated by bilateral and multilateral transmission contracts is presented. Group structures are mathematically formulated and explored and three basic types of curtailment strategies proposed for use by market participants. A more complex model is then developed, which takes into account the co-existence of bilateral and multilateral contracts with pool type dynamic supplies and demands based on bids and market clearing prices. An integrated dispatch strategy to reconcile all three types of transactions (bilateral, multilateral and pool) is then developed. Prioritization of electricity transactions and related curtailment strategies are explored and a mechanism for coordination between market participants to achieve additional economic advantages is described. A theory of security based rescheduling is presented in order to investigate the security-related aspects of operation in an unbundled and deregulated system. The impact of post-contingency corrective capability on optimal rescheduling results has been identified and the advantage of incorporating post-contingency corrective rescheduling into the objective function demonstrated. Finally

  19. DIFC-AC: INFORMATION PRIVACY PROTECTION FOR CLOUD COMPUTING SYSTEM%DIFC-AC:一种云计算中信息隐私性保护方法

    Institute of Scientific and Technical Information of China (English)

    叶志伟; 叶建伟

    2013-01-01

    With the permeation of cloud computing, this new networks computation mode also raises the information privacy protection issue, which becomes an important problem to be urgently resolved in cloud computing field. Once the data is uploaded to the cloud server, users are no longer to be able to guarantee the data is protected. In order to allow users- to autonomously authorise and control the data uploaded to the cloud, we present DIFC-AC, an access control method based on decentralised information flow control model. The core idea of DIFC-AC is to use security labels to track data flows. Data owners control the access privileges of the process on the data by setting control conditions on the labels. The design and implementation of a prototype system of DIFC-AC is presented. DIFC-AC ensures the user data privacy on the server throughout the life-time. Performance evaluation data shows that the prototype system imposes reasonably low runtime overhead.%随着云计算这种新的网络计算模式的普及,云用户信息隐私性保护问题成为云计算领域亟待解决的重要问题.当用户将数据上传到云服务器端,用户就不再能保证其数据受到保护.为了让用户对上传到云上的数据进行自主的授权和控制,提出一种基于分布式信息流控制的访问控制方法DIFC-AC,其核心思想是采用安全标签来跟踪数据的流动,数据所有者通过在标签中设置授权条件来控制进程对该数据的访问权限.提出DIFC-AC原型系统的设计与实现,DIFC-AC保证用户数据在服务器端的整个生命周期的隐私性.性能测试数据显示DIFC-AC原型系统的性能开销能够控制在合理范围之内.

  20. Vector control of three-phase AC machines system development in the practice

    CERN Document Server

    Quang, Nguyen Phung; Dittrich, J

    2015-01-01

    This book addresses the vector control of three-phase AC machines, in particular induction motors with squirrel-cage rotors (IM), permanent magnet synchronous motors (PMSM) and doubly-fed induction machines (DFIM), from a practical design and development perspective. The main focus is on the application of IM and PMSM in electrical drive systems, where field-orientated control has been successfully established in practice. It also discusses the use of grid-voltage oriented control of DFIMs in wind power plants. This second, enlarged edition includes new insights into flatness-based  nonlinear

  1. The transmission link of CAPS navigation and communication system

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The Chinese Area Positioning System (CAPS) is based on communication satellites with integrated capability, which is different from the Global Positioning System (GPS), the International Maritime Satellite Organization (Inmarsat) and so on. CAPS works at C-band, and its navigation information is not directly generated from the satellite, but from the master control station on the ground and transmitted to users via the satellite. The slightly inclined geostationary-satellite orbit (SIGSO) satellites are adopted in CAPS. All of these increase the difficulty in the design of the system and terminals. In this paper, the authors study the CAPS configuration parameters of the navigation master control station, information transmission capability, and the selection of the antenna aperture of the communication center station, as well as the impact of satellite parameters on the whole communication system from the perspective of the transmission link budget. The conclusion of availability of the CAPS navigation system is achieved. The results show that the CAPS inbound communication system forms a new low-data-rate satellite communication system, which can accommodate mass communication terminals with the transmission rate of no more than 1 kbps for every terminal. The communication center station should be configured with a large-aperture antenna (about 10-15 m); spread spectrum com- munication technology should be used with the spreading gain as high as about 40 dB; reduction of the satellite transponder gain attenuation is beneficial to improving the signal-to-noise ratio of the system, with the attenuation value of 0 or 2 dB as the best choice. The fact that the CAPS navigation system has been checked and accepted by the experts and the operation is stable till now clarifies the rationality of the analysis results. The fact that a variety of experiments and applications of the satellite communication system designed according to the findings in this paper have been

  2. The Impact Study of a Statcom on Commutation Failures in an HVDC Inverter Feeding a Weak AC System

    Science.gov (United States)

    Khatir, Mohamed; Zidi, Sid-Ahmed; Fellah, Mohammed-Karim; Hadjeri, Samir; Flitti, Mohamed

    2012-03-01

    The Static Synchronous Compensator (STATCOM) devices are pure power electronics devices that use voltage source, IGBT, IGCT or GTO based converters to generate reactive current. This paper illustrates the effect of STATCOM connected whit an HVDC inverter feeding a weak AC network, on the recovery from commutation failures following AC side disturbances. MATLAB/SIMULINK simulation results have demonstrated the robust performance of the proposed system based on the first CIGRÉ HVDC Benchmark model against commutation failures.

  3. Suggested Methods for Preventing Core Saturation Instability in HVDC Transmission Systems

    Energy Technology Data Exchange (ETDEWEB)

    Norheim, Ian

    2002-07-01

    In this thesis a study of the HVDC related phenomenon core saturation instability and methods to prevent this phenomenon is performed. It is reason to believe that this phenomenon caused disconnection of the Skagerrak HVDC link 10 August 1993. Internationally, core saturation instability has been reported at several HVDC schemes and thorough complex studies of the phenomenon has been performed. This thesis gives a detailed description of the phenomenon and suggest some interesting methods to prevent the development of it. Core saturation instability and its consequences can be described in a simplified way as follows: It is now assumed that a fundamental harmonic component is present in the DC side current. Due to the coupling between the AC side and the DC side of the HVDC converter, a subsequent second harmonic positive-sequence current and DC currents will be generated on the AC side. The DC currents will cause saturation in the converter transformers. This will cause the magnetizing current to also have a second harmonic positive-sequence component. If a high second harmonic impedance is seen from the commutation bus, a high positive-sequence second harmonic component will be present in the commutation voltages. This will result in a relatively high fundamental frequency component in the DC side voltage. If the fundamental frequency impedance at the DC side is relatively low the fundamental component in the DC side current may become larger than it originally was. In addition the HVDC control system may contribute to the fundamental frequency component in the DC side voltage, and in this way cause a system even more sensitive to core saturation instability. The large magnetizing currents that eventually will flow on the AC side cause large zero-sequence currents in the neutral conductors of the AC transmission lines connected to the HVDC link. This may result in disconnection of the lines. Alternatively, the harmonics in the large magnetizing currents may cause

  4. Voltage Stability Bifurcation Analysis for AC/DC Systems with VSC-HVDC

    Directory of Open Access Journals (Sweden)

    Yanfang Wei

    2013-01-01

    Full Text Available A voltage stability bifurcation analysis approach for modeling AC/DC systems with VSC-HVDC is presented. The steady power model and control modes of VSC-HVDC are briefly presented firstly. Based on the steady model of VSC-HVDC, a new improved sequential iterative power flow algorithm is proposed. Then, by use of continuation power flow algorithm with the new sequential method, the voltage stability bifurcation of the system is discussed. The trace of the P-V curves and the computation of the saddle node bifurcation point of the system can be obtained. At last, the modified IEEE test systems are adopted to illustrate the effectiveness of the proposed method.

  5. A Multiple-Antenna System for ISM-Band Transmission

    Directory of Open Access Journals (Sweden)

    Rinas J

    2004-01-01

    Full Text Available We present a multiple antenna system for industrial, scientific, and medical (ISM-band transmission (MASI. The hardware demonstrator was developed and realized at our institute. It enables multiple-input multiple-output (MIMO-communication applications and is capable of transmiting arbitrary signals using transmit and receive antennas in parallel. It operates in the 2.4 GHz ISM-band. The hardware concept is introduced and some design specifications are discussed. Using this transmission system, we present some measurement results to show the feasibility of MIMO concepts currently under discussion. The applications include transmit and receive diversity for single carrier and OFDM as well as blind source separation (BSS techniques.

  6. EHV/HV Underground Cable Systems for Power Transmission

    DEFF Research Database (Denmark)

    Bak, Claus Leth

    Power transmission is facing its largest challenges ever with regards to handling a transition from today’s fossil‐based power production into renewable sources of generation. We can no longer place power plants close to centres of consumption; they must be located where the natural resources...... the role of interconnecting these generation/load centres, ensuring fair reliability and redundancy of supply. Nowadays, the power transmission system must be able to handle the various sources of renewable generation in a flexible electricity market. This has the consequence that the original layout...... cables is given, and secondly, the modelling approach and validation of this is discussed. Thirdly, making up the main core of the work presented, dynamics of underground cable systems are discussed and important cases to study are highlighted, and next, protection and fault location are discussed...

  7. Portable wireless power transmission system for video capsule endoscopy.

    Science.gov (United States)

    Zhiwei, Jia; Guozheng, Yan; Bingquan, Zhu

    2014-10-01

    Wireless power transmission is considered a practical way of overcoming the power shortage of wireless capsule endoscopy (VCE). However, most patients cannot tolerate the long hours of lying in a fixed transmitting coil during diagnosis. To develop a portable wireless power transmission system for VCE, a compact transmitting coil and a portable inverter circuit driven by rechargeable batteries are proposed. The couple coils, optimized considering the stability and safety conditions, are 28 turns of transmitting coil and six strands of receiving coil. The driven circuit is designed according to the portable principle. Experiments show that the integrated system could continuously supply power to a dual-head VCE for more than 8 h at a frame rate of 30 frames per second with resolution of 320 × 240. The portable VCE exhibits potential for clinical applications, but requires further improvement and tests.

  8. Data Acquisition and Transmission System for Building Energy Consumption Monitoring

    Directory of Open Access Journals (Sweden)

    Liang Zhao

    2013-01-01

    Full Text Available Building energy consumption monitoring and management system have been developed widely in China in order to gain the real-time data of energy consumption in buildings for analyzing it in the next state work. This paper describes a low-cost and small-sized collector based on the STM32 microcontroller, which can be placed in a building easily to implement the work of data acquisition, storage, and transmission. The collector gathers the electricity, water, heat, and energy consumption data through the RS485 field bus and stores the data into an SD card with mass storage, finally, using Internet to finish the communication and transmission to data server through TCP protocol. The collector has been used in application for two years, and the results show that the system is reliable and stable.

  9. Adaptive Image Transmission Scheme over Wavelet-Based OFDM System

    Institute of Scientific and Technical Information of China (English)

    GAOXinying; YUANDongfeng; ZHANGHaixia

    2005-01-01

    In this paper an adaptive image transmission scheme is proposed over Wavelet-based OFDM (WOFDM) system with Unequal error protection (UEP) by the design of non-uniform signal constellation in MLC. Two different data division schemes: byte-based and bitbased, are analyzed and compared. Different bits are protected unequally according to their different contribution to the image quality in bit-based data division scheme, which causes UEP combined with this scheme more powerful than that with byte-based scheme. Simulation results demonstrate that image transmission by UEP with bit-based data division scheme presents much higher PSNR values and surprisingly better image quality. Furthermore, by considering the tradeoff of complexity and BER performance, Haar wavelet with the shortest compactly supported filter length is the most suitable one among orthogonal Daubechies wavelet series in our proposed system.

  10. Energy-Efficient Transmission Schemes in Cooperative Cellular Systems

    CERN Document Server

    Yang, Wei; Wang, Ying; Sun, Wanlu

    2010-01-01

    Energy-efficient communication is an important requirement for mobile devices, as the battery technology has not kept up with the growing requirements stemming from ubiquitous multimedia applications. This paper considers energy-efficient transmission schemes in cooperative cellular systems with unbalanced traffic between uplink and downlink. Theoretically, we derive the optimal transmission data rate, which minimizes the total energy consumption of battery-powered terminals per information bit. The energy-efficient cooperation regions are then investigated to illustrate the effects of relay locations on the energy-efficiency of the systems, and the optimal relay location is found for maximum energy-efficiency. Finally, numerical results are provided to demonstrate the tradeoff between energy-efficiency and spectral efficiency.

  11. Rigorous theoretical derivation of lumped models to transmission line systems

    Institute of Scientific and Technical Information of China (English)

    Zhao Jixiang

    2012-01-01

    By virtue of the negative electric parameter concept,i.e.negative lumped resistance,inductance,conductance and capacitance (N-RLGC),the lumped equivalent models of transmission line systems,including the circuit model,two-port π-network and T-network,are given.We start from the N-segment-ladder-like equivalent networks composed distributed parameters,and achieve the input impedance in the form of a continued fraction.Utilizing the continued fraction theory,the expressions of input impedance are obtained under three kinds of extreme cases,i.e.the load impedances are equal to zero,infinity and characteristic impedance,respectively.When the number of segment N is limited to infinity,they are transformed to lumped elements.Comparison between the distributed model and lumped model of transmission lines,the expression of tanh yd,which is the key term in the transmission line equations,are obtained by RLGC,furthermore,according to input admittance,admittance matrix and ABCD matrix of transmission lines,the lumped equivalent circuit models,π-networks and T-networks have been given.The models are verified in the frequency and time domain,respectively,showing that the models are accurate and efficient.

  12. A GIS-based Power Transmission Management Information System

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    <正>Based on analyzing the shortcomings of electric power enterprise in traditional operation pattern,this paper combines components GIS with the application of management information system,and uses the structure which unifies three layers C/S and B/S.Also,proposed using the GPS intellectualization patrol.This may be useful to guarantees the transmission line’s operation to be safe and stable.

  13. EHV/HV Underground Cable Systems for Power Transmission

    DEFF Research Database (Denmark)

    Bak, Claus Leth

    are to be found. One very good example of this is offshore wind power plants. The current transmission system is laid out in a traditional manner, which is based on the idea of not transporting power over longer distances as the power plants have been located near centres of consumption. It has merely played....... Many interesting research topics are still open, especially with regards to asset management tools....

  14. Transmission of order in some unusual dilute systems

    Science.gov (United States)

    Adler, Joan; Palmer, R. G.; Meyer, H.

    1987-03-01

    As a system is diluted, the critical temperature T may fall to zero at a concentration X sub c greater than the percolation concentration, because mere connectivity does not guarantee the transmission of order even at T = 0. Detailed results, including bounds on X sub c, are presented for the three-state Potts antiferromagnet on a triangular lattice and for quadrupolar models of (o-H2)x(p-H2)1-x mixtures on fcc and triangular lattices.

  15. Static Measurements on HTS Coils of Fully Superconducting AC Electric Machines for Aircraft Electric Propulsion System

    Science.gov (United States)

    Choi, Benjamin B.; Hunker, Keith R.; Hartwig, Jason; Brown, Gerald V.

    2017-01-01

    The NASA Glenn Research Center (GRC) has been developing the high efficiency and high-power density superconducting (SC) electric machines in full support of electrified aircraft propulsion (EAP) systems for a future electric aircraft. A SC coil test rig has been designed and built to perform static and AC measurements on BSCCO, (RE)BCO, and YBCO high temperature superconducting (HTS) wire and coils at liquid nitrogen (LN2) temperature. In this paper, DC measurements on five SC coil configurations of various geometry in zero external magnetic field are measured to develop good measurement technique and to determine the critical current (Ic) and the sharpness (n value) of the super-to-normal transition. Also, standard procedures for coil design, fabrication, coil mounting, micro-volt measurement, cryogenic testing, current control, and data acquisition technique were established. Experimentally measured critical currents are compared with theoretical predicted values based on an electric-field criterion (Ec). Data here are essential to quantify the SC electric machine operation limits where the SC begins to exhibit non-zero resistance. All test data will be utilized to assess the feasibility of using HTS coils for the fully superconducting AC electric machine development for an aircraft electric propulsion system.

  16. 1000 kV 交流特高压输电线路运行特性分析%Analysis of 1 000 kV AC Ultra High Voltage Power Transmission Line Operation Characteristics

    Institute of Scientific and Technical Information of China (English)

    曹旭佳

    2015-01-01

    1000 kV 交流特高压输电线路是解决我国电力能源分布不均匀,降低电力负荷的有效手段。1000 kV 交流特高压线路的维护工作也开始受到社会各界的广泛关注。为了保障交流特高压线路能够安全运行,文章分析了1000 kV 交流特高压输电线路运行特性,借鉴了国外先进经验,总结了其中的关键技术。%1 000 kV AC UHV transmission line is an effective means of uneven distribution of electric energy,reduce the power load solutions,the maintenance work of 1 000 kV AC UHV line has begun to attract widespread concern in the community,in order to protect AC UHV safe operation,we must summarize the key technologies,learn from foreign ad-vanced experience,this paper analyzes the operating characteristics of 1 000 kV UHV AC transmission lines.

  17. Droop-free Team-oriented Control for AC Distribution Systems

    DEFF Research Database (Denmark)

    Nasirian, Vahidreza; Shafiee, Qobad; Guerrero, Josep M.;

    2015-01-01

    Droop control is conventionally used for load sharing in AC distribution systems. Despite decentralized nature of the droop technique, it requires centralized secondary control to provide voltage and frequency regulation across the system. Distributed control, as an alternative to the centralized...... in proportion to their rated powers. The active power regulator addresses frequency synchronization without using any frequency feedback/measurement, which improves the system dynamic. Simulation results are provided to verify the performance of the proposed control methodology....... controller, offers improved reliability and scalability. Accordingly, a droopfree distributed framework is proposed that fine-tunes the voltage and frequency at each source to handle 1) Voltage regulation, 2) Reactive power sharing, 3) Frequency synchronization, and 4) Active power sharing. The controller...

  18. Research of novel oscillating wire feeding system using the AC servo motor

    Institute of Scientific and Technical Information of China (English)

    杨世彦; 于志; 刘喆

    2003-01-01

    With the background of the control of additional mechanical force droplet transfer in MIG/MAG welding, regarding the AC servo motor as core, a novel oscillating wire feeding system has been developed with excellent performances of control and dynamic acceleration which is tested. System constitution and operation principle are introduced in this paper. Influences of parameters on dynamic acceleration performance are analyzed and discussed emphatically, such as oscillating frequency, oscillating amplitude and draw-back speed. Experimental result indicates that according to the technique of welding control, the novel wire feeding system responds rapidly to various kinds of control orders of wire feeding and draw-back, and realizes flexible control of welding wire axial movement, including dynamic shifting,oscillating and so on.

  19. Insulation measurement and supervision in live AC and DC unearthed systems

    CERN Document Server

    Olszowiec, Piotr

    2013-01-01

    Low voltage unearthed (IT) AC and DC systems are commonly applied for supply of power and control circuits in industry, transportation, medical objects etc. The main reasons for their use are high reliability and numerous advantages offered by isolating them against ground. Insulation level is a decisive factor for networks operational reliability and safety. Insufficient insulation-to-ground resistance can cause various disturbances. Though ground faults in IT systems do not make networks operation impossible, they may cause severe problems with their safe functioning. In this book the most important issues concerning normal operation and ground fault phenomena are described in concise form. Numerous methods of insulation resistance and capacitance measurement in live circuits are presented. Important other procedures of  these parameters determination based on measurement and calculation are explained and reviews of selected insulation resistance measurement devices as well as earth fault locating systems ...

  20. Insulation measurement and supervision in live AC and DC unearthed systems

    CERN Document Server

    Olszowiec, Piotr

    2014-01-01

    Low voltage unearthed (IT) AC and DC systems are commonly applied for supply of power and control circuits in industry, transportation, medical objects etc. The main reasons for their use are high reliability and numerous advantages offered by isolating them against ground. Insulation level is a decisive factor for networks operational reliability and safety. Insufficient insulation-to-ground resistance can cause various disturbances. Though ground faults in IT systems do not make networks operation impossible, they may cause severe problems with their safe functioning. In this book the most important issues concerning normal operation and ground fault phenomena are described in concise form. Numerous methods of insulation resistance and capacitance measurement in live circuits are presented. Important other procedures of  these parameters determination based on measurement and calculation are explained and reviews of selected insulation resistance measurement devices as well as earth fault locating systems ...

  1. Lowest of AC-DC power output for electrostrictive polymers energy harvesting systems

    Science.gov (United States)

    Meddad, Mounir; Eddiai, Adil; Hajjaji, Abdelowahed; Guyomar, Daniel; Belkhiat, Saad; Boughaleb, Yahia; Chérif, Aida

    2013-11-01

    Advances in technology led to the development of electronic circuits and sensors with extremely low electricity consumption. At the same time, structural health monitoring, technology and intelligent integrated systems created a need for wireless sensors in hard to reach places in aerospace vehicles and large civil engineering structures. Powering sensors with energy harvesters eliminates the need to replace batteries on a regular basis. Scientists have been forced to search for new power source that are able to harvested energy from their surrounding environment (sunlight, temperature gradients etc.). Electrostrictive polymer belonging to the family of electro-active polymers, offer unique properties for the electromechanical transducer technology has been of particular interest over the last few years in order to replace conventional techniques such as those based on piezoelectric or electromagnetic, these materials are highly attractive for their low-density, with large strain capability that can be as high as two orders of magnitude greater than the striction-limited, rigid and fragile electroactive ceramics. Electrostrictive polymers sensors respond to vibration with an ac output signal, one of the most important objectives of the electronic interface is to realize the required AC-DC conversion. The goal of this paper is to design an active, high efficiency power doubler converter for electrostrictive polymers exclusively uses a fraction of the harvested energy to supply its active devices. The simulation results show that it is possible to obtain a maximum efficiency of the AC-DC converter equal to 80%. Premiliminary experimental measurements were performed and the results obtained are in good agreement with simulations.

  2. Automatic Control Systems (ACS for Generation and Sale of Electric Power Under Conditions of Industry-Sector Liberalization

    Directory of Open Access Journals (Sweden)

    Yu. Petrusha

    2013-01-01

    Full Text Available Possible risks pertaining to transition of electric-power industry to market relations have been considered in the paper. The paper presents an integrated ACS for generation and sale of electric power as an improvement of methodology for organizational and technical management. The given system is based on integration of operating Automatic Dispatch Control System (ADCS and developing Automatic Electricity Meter Reading System (AEMRS. The paper proposes to form an inter-branch sector of ACS PLC (Automatic Control System for Prolongation of Life Cycle users which is oriented on provision of development strategy.

  3. Control and Simulation of Continuously Variable Transmission for Electric Transmission System

    Institute of Scientific and Technical Information of China (English)

    张豫南; 葛蕴珊; 马晓军; 臧克茂

    2004-01-01

    According to the study of electric transmission, the concept of the fore and the aft power chain is presented. The control method of continuously variable transmission is established in the aft chain of electric transmission based on brushless DC motor. A fuzzy controller is designed with continuous fuzzy variables and the simulation module of the aft power chain is proved by test. The fuzzy controller controls the process of continuously variable transmission steadily and the acceleration of vehicle is quick according to simulation results. The elementary performance exhibited in the simulation is a foundation for the further study of the electric transmission track vehicle.

  4. Downlink transmission in multi-carrier systems with reduced feedback

    DEFF Research Database (Denmark)

    Wang, Yuanye; Pedersen, Klaus; Sørensen, Troels Bundgaard

    2010-01-01

    in this paper we address the problem of reducing the feedback for the downlink transmission in multi-carrier systems. In these systems multiple Component Carriers (CCs) are aggregated together to form a wide spectrum. Consequently, a large feedback overhead is required to report the channel quality...... information over such a wide bandwidth. We first generalize two existing feedback reduction techniques, and then propose a new one. These techniques use different feedback schemes across the CCs, or allow some CCs to be un-reported, for the purpose of reducing the amount of feedback. Performance...

  5. A multicarrier TDM transmission system for DBS-A

    Science.gov (United States)

    Campanella, S. J.

    1992-03-01

    Satellite communications service for space based broadcasting has been suggested by the National Research Council's Technical Operation's Committee for the Voice of America. The service is referred to as direct broadcast from space-audio (DBS-A). This paper presents a concept incorporating low bit rate source coding for voice and music, digital modulation, forward error correction coding and Viterbi decoding, multiple satellite beams, and multiple carrier time division multiplexed (TDM) transmission to provide a system capable of world wide coverage. The system provides the capability to narrow cast to specific geographically clustered audiences. Emphasis is on the space segment (transmitter) and earth segment (receiver) using the techniques mentioned above.

  6. A novel fiber audio transmission system for secure communication

    Institute of Scientific and Technical Information of China (English)

    SU Ke; JIA Bo

    2005-01-01

    A new,simple and efficient fiber audio transmission method for the long distance secure communication is presented, which performs signal modulation by the strain-optic effects and signal demodulation by the all-fiber interferometer. The interferometer is a truly path-matched device, which eliminates much of the undesirable noise by combining the reference and the sensing arms within the same optical fiber. The sinusoidal signals adopted in the experiment are in a frequency range of 300 HZ-3 400 HZ and of the multi-frequency, and the system shows good capabilities, robust security and maintenance of audio integrity. The device may be applicable in the field of point to point secure communication of 40 kilometer long transmission range.

  7. ac and dc conductivity, magnetoresistance, and scaling in cellular percolation systems

    Science.gov (United States)

    Chiteme, C.; McLachlan, D. S.

    2003-01-01

    Percolation phenomena, which include the ac and dc conductivity, dielectric constant, and magnetoresistance, are studied in a series of seven cellular composites, consisting of small conductor particles embedded on the surface of larger insulator particles. Carbon black (ground and unground), graphite, graphite boron-nitride, niobium carbide, nickel, and magnetite (Fe3O4) powders were the conducting components with talc-wax powder as the common insulating component. The dc conductivity results were fitted to the standard percolation equations and to a two-exponent phenomenological equation, which yields the percolation parameters σi, σc, s, t, and φc in the ideal limits. Both universal and nonuniversal values of s and t are measured in the systems. Close to the percolation threshold (φc), the ac conductivity (σmr) and the dielectric constant (ɛmr) are found to scale as σmr∝ωu and ɛmr∝ω-v. All these exponents are examined using the most recent theories and compared with previous studies. The dielectric constant exponent (s'), from ɛmr∝(φc-φ)- s', is shown to be frequency dependent. The exponents gc (magnetoresistance) and tm (from magnetoconductivity) in composites are not yet clearly understood but these and previous results show that tm>t. dc scaling is shown in a real composite comprising Fe3O4 and talc wax.

  8. The SLUGGS Survey: HST/ACS Mosaic Imaging of the NGC 3115 Globular Cluster System

    CERN Document Server

    Jennings, Zachary G; Romanowsky, Aaron J; Brodie, Jean P; Arnold, Jacob A; Lin, Dacheng; Irwin, Jimmy A; Sivakoff, Gregory R; Wong, Ka-Wah

    2014-01-01

    We present HST/ACS $g$ and $z$ photometry and half-light radii $R_{\\rm h}$ measurements of 360 globular cluster (GC) candidates around the nearby S0 galaxy NGC 3115. We also include Subaru/Suprime-Cam $g$, $r$, and $i$ photometry of 421 additional candidates. The well-established color bimodality of the GC system is obvious in the HST/ACS photometry. We find evidence for a "blue tilt" in the blue GCs, wherein the blue GCs get redder as luminosity increases, indicative of a mass-metallicity relationship. We find a color gradient in both the red and blue subpopulations, with each group of clusters becoming bluer at larger distances from NGC 3115. The gradient is of similar strength in both subpopulations, but is monotonic and more significant for the blue clusters. On average, the blue clusters have ~10% larger $R_{\\rm h}$ than the red clusters. This average difference is less than is typically observed for early-type galaxies but does match that measured in the literature for M104, suggesting that morphology a...

  9. A Novel Active Bouncer System for Klystron Modulators with Constant AC Power Consumption

    CERN Document Server

    Cabaleiro Magallanes, F; Viarouge, P; Cros, J; De Almeida Martins, C

    2014-01-01

    This paper presents the principles and design methodologies of a novel active bouncer system, to be implemented in a transformer-based klystron modulator, which is able to meet two different objectives: 1. Regulate the output pulse voltage flattop, and 2. Attenuate the power fluctuation withdrawn from the AC network. This solution allows the utilization of a standard constant voltage / constant current power supply as a capacitor charger. The solution consists of a 4-quadrant switching converter placed in series with the main capacitor bank (forming a unique element in parallel with the capacitor charger), controlled with specific feed-back loops to achieve the two objectives. The complete design method, including a numerical optimization, of the whole system, is presented in the paper. Analyses of the compromises between the active bouncer specifications and the other modulator sub-components design is presented as well.

  10. Power and signal transmission for mobile teleoperated systems

    Energy Technology Data Exchange (ETDEWEB)

    Morris, A.C. Jr.; Hamel, W.R.

    1985-01-01

    Appropriate means must be furnished for supplying power and for sending controlling commands to mobile teleoperated systems. Because a sizable number of possibilities are available for such applications, methods used in designing both the power and communications systems built into mobile vehicles that serve in radiological emergencies must be carefully selected. This paper describes a number of umbilical, on-board, and wireless systems used in tranmitting power that are available for mobile teleoperator services. The pros and cons of selecting appropriate methods from a list of possible communication systems (wired, fiber optic, and radio frequency) are also examined. Moreover, hybrid systems combining wireless power transmissions with command-information signals are also possible.

  11. 交流输电线路模型在山火条件下的击穿机理%Air Gap Breakdown Mechanism of Model AC Transmission Line Under Forest Fires

    Institute of Scientific and Technical Information of China (English)

    吴田; 胡毅; 阮江军; 刘凯; 刘庭; 陈成

    2011-01-01

    With the development transmission system construction in China, many power transmission channels are across mountain areas and occurrence of fire under transmission lines is responsible for a great number of line trips and interruptions. Consequently, the influences of electrode, flame temperature, alkali metal salts KC1, solid particle and air gap filled with smoke and flame on the conductor-plane gap breakdown features are studied by fire of crib. Experimental results show that, AC breakdown voltage is reduced to one-third that of conductor plane gaps under standard conditions; when particles are on the surface of conductor, the breakdown voltage is reduced; the flame conductivity is increased after alkali metal salts are added into the flame and flashover voltage is 33% lower than that in the flame. So transmission line forest fire induced flashover is attributed to flame temperature, electrons and ions and solid particles.%近年来我国电网建设得到了长足发展,越来越多的线路经过山区,而在输电线路附近发生的林火常常引发线路发生跳闸或停运事故,严重威胁到电力系统的安全和可靠性.为了分析交流输电线路在山火条件下的击穿机理,采用导线-板间隙模拟输电线路的相地间隙和模拟山火的方法研究了电极、温度、碱金属盐KCl、导体表面的颗粒以及烟气与火焰混合区对导线-板间隙绝缘的影响.试验结果表明:在山火条件下,击穿电压出现明显降低,特别是火焰的高温和颗粒会导致间隙的绝缘强度发生剧烈降低.由输电线路因山火闪络的分析得到,线路间隙绝缘强度剧烈降低是火焰温度、电子和离子以及固体颗粒共同作用的结果,单一因素的作用不足以导致输电线路绝缘发生明显下降而引发跳闸事故.

  12. Lightning location system supervising Swedish power transmission network

    Science.gov (United States)

    Melin, Stefan A.

    1991-01-01

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

  13. Performance analysis of a model-sized superconducting DC transmission system based VSC-HVDC transmission technologies using RTDS

    Science.gov (United States)

    Dinh, Minh-Chau; Ju, Chang-Hyeon; Kim, Sung-Kyu; Kim, Jin-Geun; Park, Minwon; Yu, In-Keun

    2012-08-01

    The combination of a high temperature superconducting DC power cable and a voltage source converter based HVDC (VSC-HVDC) creates a new option for transmitting power with multiple collection and distribution points for long distance and bulk power transmissions. It offers some greater advantages compared with HVAC or conventional HVDC transmission systems, and it is well suited for the grid integration of renewable energy sources in existing distribution or transmission systems. For this reason, a superconducting DC transmission system based HVDC transmission technologies is planned to be set up in the Jeju power system, Korea. Before applying this system to a real power system on Jeju Island, system analysis should be performed through a real time test. In this paper, a model-sized superconducting VSC-HVDC system, which consists of a small model-sized VSC-HVDC connected to a 2 m YBCO HTS DC model cable, is implemented. The authors have performed the real-time simulation method that incorporates the model-sized superconducting VSC-HVDC system into the simulated Jeju power system using Real Time Digital Simulator (RTDS). The performance analysis of the superconducting VSC-HVDC systems has been verified by the proposed test platform and the results were discussed in detail.

  14. Soft Computing Technique Based Enhancement of Transmission System Lodability Incorporating Facts

    Directory of Open Access Journals (Sweden)

    T. Vara Prasad,

    2014-07-01

    Full Text Available Due to the growth of electricity demands and transactions in power markets, existing power networks need to be enhanced in order to increase their loadability. The problem of determining the best locations for network reinforcement can be formulated as a mixed discrete-continuous nonlinear optimization problem (MDCP. The complexity of the problem makes extensive simulations necessary and the computational requirement is high. This paper compares the effectiveness of Evolutionary Programming (EP and an ordinal optimization (OO technique is proposed in this paper to solve the MDCP involving two types of flexible ac transmission systems (FACTS devices, namely static var compensator (SVC and thyristor controlled series compensator (TCSC, for system loadability enhancement. In this approach, crude models are proposed to cope with the complexity of the problem and speed up the simulations with high alignment confidence. The test and Validation of the proposed algorithm are conducted on IEEE 14–bus system and 22-bus Indian system.Simulation results shows that the proposed models permit the use of OO-based approach for finding good enough solutions with less computational efforts.

  15. Adaptive transmission schemes for MISO spectrum sharing systems

    KAUST Repository

    Bouida, Zied

    2013-06-01

    We propose three adaptive transmission techniques aiming to maximize the capacity of a multiple-input-single-output (MISO) secondary system under the scenario of an underlay cognitive radio network. In the first scheme, namely the best antenna selection (BAS) scheme, the antenna maximizing the capacity of the secondary link is used for transmission. We then propose an orthogonal space time bloc code (OSTBC) transmission scheme using the Alamouti scheme with transmit antenna selection (TAS), namely the TAS/STBC scheme. The performance improvement offered by this scheme comes at the expense of an increased complexity and delay when compared to the BAS scheme. As a compromise between these schemes, we propose a hybrid scheme using BAS when only one antenna verifies the interference condition and TAS/STBC when two or more antennas are illegible for communication. We first derive closed-form expressions of the statistics of the received signal-to-interference-and-noise ratio (SINR) at the secondary receiver (SR). These results are then used to analyze the performance of the proposed techniques in terms of the average spectral efficiency, the average number of transmit antennas, and the average bit error rate (BER). This performance is then illustrated via selected numerical examples. © 2013 IEEE.

  16. The transmission link of CAPS navigation and communication system

    Institute of Scientific and Technical Information of China (English)

    CUI JunXia; SHI HuLi; CHEN JiBin; PEI Jun

    2009-01-01

    The Chinese Area Positioning System (CAPS) is based on communication satellites with integrated oapability,whioh is different from the Global Positioning System (GPS),the International Maritime Satellite Organization (Inmarsat) and so on.CAPS works at G-band,and its navigation information ie not directly generated from the satellite,but from the master control station on the ground and transmitted to users via the satellite.The slightly inclined geostationary-satellite orbit (SIGSO) satellites are adopted in CAPS.All of these increase the difficulty in the design of the system and terminals.In this paper,the authors study the CAPS oonfiguration parameters of the navigation master control station,information transmission capability,and the selection of the antenna aperture of the communication oenter station,as well as the impact of satellite parameters on the whole communication system from the perspective of the transmission link budget.The conclusion of availability of the GAPS navigation system is achieved.The results show that the GAPS inbound communication system forms a new low-data-rate satellite communicaUon system,which can accommodate mass communication termihale with the transmission rate of no more than 1 kbps for every terminal.The communication center station should be configured with a large-aperture antenna (about 10--15 m); spread spectrum communication technology should be used with the spreading gain as high as about 40 dB; reduction of the satellite transponder gain attenuation is beneficial to improving the signal-to-noise ratio of the system,with the attenuation value of 0 or 2 dB as the best choice.The fact that the GAPS navigation system has been checked and aooepted by the experts and the operation is stable till now larifies the rationality of the analysis results.The fact that a variety of experiments and applications of the satellite communication system designed according to the findings in this paper have been successfully carried out

  17. Suggested Methods for Preventing Core Saturation Instability in HVDC Transmission Systems

    Energy Technology Data Exchange (ETDEWEB)

    Norheim, Ian

    2002-07-01

    In this thesis a study of the HVDC related phenomenon core saturation instability and methods to prevent this phenomenon is performed. It is reason to believe that this phenomenon caused disconnection of the Skagerrak HVDC link 10 August 1993. Internationally, core saturation instability has been reported at several HVDC schemes and thorough complex studies of the phenomenon has been performed. This thesis gives a detailed description of the phenomenon and suggest some interesting methods to prevent the development of it. Core saturation instability and its consequences can be described in a simplified way as follows: It is now assumed that a fundamental harmonic component is present in the DC side current. Due to the coupling between the AC side and the DC side of the HVDC converter, a subsequent second harmonic positive-sequence current and DC currents will be generated on the AC side. The DC currents will cause saturation in the converter transformers. This will cause the magnetizing current to also have a second harmonic positive-sequence component. If a high second harmonic impedance is seen from the commutation bus, a high positive-sequence second harmonic component will be present in the commutation voltages. This will result in a relatively high fundamental frequency component in the DC side voltage. If the fundamental frequency impedance at the DC side is relatively low the fundamental component in the DC side current may become larger than it originally was. In addition the HVDC control system may contribute to the fundamental frequency component in the DC side voltage, and in this way cause a system even more sensitive to core saturation instability. The large magnetizing currents that eventually will flow on the AC side cause large zero-sequence currents in the neutral conductors of the AC transmission lines connected to the HVDC link. This may result in disconnection of the lines. Alternatively, the harmonics in the large magnetizing currents may cause

  18. Multi-core Fibers in Submarine Networks for High-Capacity Undersea Transmission Systems

    DEFF Research Database (Denmark)

    Nooruzzaman, Md; Morioka, Toshio

    2017-01-01

    Application of multi-core fibers in undersea networks for high-capacity submarine transmission systems is studied. It is demonstrated how different architectures of submerged branching unit affect network component counts in long-haul undersea transmission systems......Application of multi-core fibers in undersea networks for high-capacity submarine transmission systems is studied. It is demonstrated how different architectures of submerged branching unit affect network component counts in long-haul undersea transmission systems...

  19. Dynamics of energy transport and entropy production in ac-driven quantum electron systems

    Science.gov (United States)

    Ludovico, María Florencia; Moskalets, Michael; Sánchez, David; Arrachea, Liliana

    2016-07-01

    We analyze the time-resolved energy transport and the entropy production in ac-driven quantum coherent electron systems coupled to multiple reservoirs at finite temperature. At slow driving, we formulate the first and second laws of thermodynamics valid at each instant of time. We identify heat fluxes flowing through the different pieces of the device and emphasize the importance of the energy stored in the contact and central regions for the second law of thermodynamics to be instantaneously satisfied. In addition, we discuss conservative and dissipative contributions to the heat flux and to the entropy production as a function of time. We illustrate these ideas with a simple model corresponding to a driven level coupled to two reservoirs with different chemical potentials.

  20. Harmonic Analysis of AC-DC Topologies and their Impacts on Power Systems

    Directory of Open Access Journals (Sweden)

    Mukhtiar Ahmed Mahar

    2011-01-01

    Full Text Available Power Electronic Converters are commonly used in different applications because of high efficiency and low cost. Due to latest advancement in semiconductor devices it is difficult to draw the boundaries for applications of power electronic topologies. These topologies are variable structure systems and generate harmonics during the operation which will affect the power quality when are connected to system network. Rectifier is a big family of converters and used when ac-dc conversion is needed. These converters are widely used in distribution system. Therefore, it is necessary to predict the harmonic levels of these converters and also observe their impacts on system network. Pakistan now days facing serious energy crises specially, in power sector due to increase in load demand. To bridge the gap between load demand and generation of electricity, various steps are taken by power companies and government. The steps include the up gradation of existing power plants, generation of power from rental power plants, installation of renewable power sources, taking different steps of demand side management etc. But efforts of power companies on power quality is still lacking. This research work focuses on power quality of the system network. In this work, harmonics of single phase and three phase full bridge diode rectifiers are analyzed by using the fast fourier transform method of MATLAB. The effects of harmonics on the system network are also discussed.

  1. Simple uniaxial pressure device for ac-susceptibility measurements suitable for closed cycle refrigerator system.

    Science.gov (United States)

    Arumugam, S; Manivannan, N; Murugeswari, A

    2007-06-01

    A simple design of the uniaxial pressure device for the measurement of ac-susceptibility at low temperatures using closed cycle refrigerator system is presented for the first time. This device consists of disc micrometer, spring holder attachment, uniaxial pressure cell, and the ac-susceptibility coil wound on stycast bobbin. It can work under pressure till 0.5 GPa and at the temperature range of 30-300 K. The performance of the system at ambient pressure is tested and calibrated with standard paramagnetic salts [Gd(2)O(3), Er(2)O(3), and Fe(NH(4)SO(4))(2)6H(2)O], Fe(3)O(4), Gd metal, Dy metal, superconductor (YBa(2)Cu(3)O(7)), manganite (La(1.85)Ba(0.15)MnO(3)), and spin glass material (Pr(0.8)Sr(0.2)MnO(3)). The performance of the uniaxial pressure device is demonstrated by investigating the uniaxial pressure dependence of La(1.85)Ba(0.15)MnO(3) single crystal with P||c axis. The Curie temperature (T(c)) decreases as a function of pressure with P||c axis (dT(c)dP(||c axis)=-11.65 KGPa) up to 46 MPa. The design is simple, is user friendly, and does not require pressure calibration. Measurement can even be made on thin and small size oriented crystals. The failure of the coil is remote under uniaxial pressure. The present setup can be used as a multipurpose uniaxial pressure device for the measurement of Hall effect and thermoelectric power with a small modification in the pressure cell.

  2. Marine High Voltage Power Conditioning and Transmission System with Integrated Storage DE-EE0003640 Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Frank Hoffmann, PhD; Aspinall, Rik

    2012-12-10

    Design, Development, and test of the three-port power converter for marine hydrokinetic power transmission. Converter provides ports for AC/DC conversion of hydrokinetic power, battery storage, and a low voltage to high voltage DC port for HVDC transmission to shore. The report covers the design, development, implementation, and testing of a prototype built by PPS.

  3. Generation and transmission of greenhouse gases in river system

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu; WANG Shu-bo

    2016-01-01

    The research progress on the current domestic and foreign about river water system of the greenhouse gas methane(CH4), and nitrous oxide(N2O) generation, transmission and release mechanism are reviewed in this paper. At present, at home and abroad of river water system of methane production and release of the driving factors and mechanism has been basically clear, but the N2O production mechanism is not clear, multi factor interaction of river water system of N2O production and release of complex, in different regions and time of result differences. The calculation of water flux of N2O river discharge coefficient of river IPCC released based on N2O, the release amount may underestimate the river water N2O.

  4. A portable wireless power transmission system for video capsule endoscopes.

    Science.gov (United States)

    Shi, Yu; Yan, Guozheng; Zhu, Bingquan; Liu, Gang

    2015-01-01

    Wireless power transmission (WPT) technology can solve the energy shortage problem of the video capsule endoscope (VCE) powered by button batteries, but the fixed platform limited its clinical application. This paper presents a portable WPT system for VCE. Besides portability, power transfer efficiency and stability are considered as the main indexes of optimization design of the system, which consists of the transmitting coil structure, portable control box, operating frequency, magnetic core and winding of receiving coil. Upon the above principles, the correlation parameters are measured, compared and chosen. Finally, through experiments on the platform, the methods are tested and evaluated. In the gastrointestinal tract of small pig, the VCE is supplied with sufficient energy by the WPT system, and the energy conversion efficiency is 2.8%. The video obtained is clear with a resolution of 320×240 and a frame rate of 30 frames per second. The experiments verify the feasibility of design scheme, and further improvement direction is discussed.

  5. Use of system approaches for transmission open access pricing

    Energy Technology Data Exchange (ETDEWEB)

    Rudnick, H.; Soto, M.; Palma, R. [Pontificia University Catolica de Chile, Santiago (Chile)

    1999-02-01

    The Latin American deregulated markets have based their open access schemes on a concept that considers a multilateral use of the transmission system, with all agents contributing to the financing of a common network based on physical and economic usage, irrespective of commercial arrangements. The paper describes the concept and the existing schemes and contributes with the formulation of alternative numerical approaches for open access pricing, taking into account energy and capacity use of the system by the participant agents. Distribution factors based on DC power flows are the basic elements of the formulation, which is built based on different physical and economic considerations. The approaches are numerically evaluated in the Chilean main interconnected electrical system, with a comparison of the resultant impacts on generators and consumers. (author)

  6. Carbon footprint of the Danish electricity transmission and distribution systems

    DEFF Research Database (Denmark)

    Turconi, Roberto; Astrup, Thomas Fruergaard

    &D) will likely grow. Several studies are available on renewable energy technologies, but only a few on transmission of electricity, and none on its distribution. This study provides life cycle inventory data for electricity distribution networks, and a life cycle GHG accounting of the Danish T&D networks....... The purpose was to evaluate the potential importance of environmental impacts associated with T&D in current and future electricity systems. Including the emissions from electricity T&D is needed to provide a full carbon footprint of electricity systems, and is essential to properly assess the environmental...... consequences of potential changes in an electricity system. So far, the basis for such assessments has not been available. The functional unit of this study was the delivery of one kWh of electricity in Denmark. The 2010 Danish electricity T&D networks were modeled, including power lines, transformers...

  7. 75 FR 3223 - California Independent System Operator Corporation; Midwest Independent Transmission System...

    Science.gov (United States)

    2010-01-20

    ... a subsequent notice. \\1\\ Wholesale Competition in Regions with Organized Electric Market, Order No... the responsiveness of regional transmission organizations (RTOs) and independent system operators... lead to decisions that do not adequately consider the price of electricity to residential consumers....

  8. A flexible computerized system for environmental data acquisition and transmission

    Science.gov (United States)

    Zappalà, G.

    2009-04-01

    In recent years increasing importance has been addressed to the knowledge of the marine environment, either to help detecting and understanding global climate change phenomena, or to protect and preserve those coastal areas, where multiple interests converge (linked to the tourism, recreational or productive activities…) and which suffer greater impact from anthropogenic activities; this has in turn stimulated the start of research programs devoted to the monitoring and surveillance of these particular zones, coupling the needs for knowledge, sustainable development and exploitation of natural resources. There is an increasing need to have data available in real time or near real time in order to intervene in emergency situations. Cabled or wireless data transmission can be used. The first allows the transmission of a higher amount of data only in coastal sites, while the second gives a bigger flexibility in terms of application to different environments; more, using mobile phone services (either terrestrial or satellite), it is possible to allocate the data centre in the most convenient place, without any need of proximity to the sea. Traditional oceanographic techniques, based on ship surveys, hardly fit the needs of operational oceanography, because of their high cost and fragmentary nature, both in spatial and temporal domains. To obtain a good synopticity, it is necessary to complement traditional ship observations with measurements from fixed stations (buoys moored in sites chosen to be representative of wider areas, or to constitute a sentinel against the arrival of pollutants), satellite observations, use of ships of opportunity and of newly developed instruments, like the gliders, or towed sliding devices, like the SAVE. Modern instruments rely on an electronic heart; an integrated hardware-software system developed in Messina is here presented, used in various versions to control data acquisition and transmission on buoys or on ship

  9. Fast Decoupled Power Flow for Power System with High Voltage Direct Current Transmission Line System

    Directory of Open Access Journals (Sweden)

    Prechanon Kumkratug

    2010-01-01

    Full Text Available Problem statement: High voltage direct current transmission line system has been widely applied for control power flow in power system. The power flow analysis was the one of powerful tools by which the power system equipped was analyzed both for planning and operation strategies. Approach: This study presented the method to analyze power flow of power system consisted of HVDC system. HVDC was modeled as the complex power injections. The presented complex power injected was incorporated into the existing power flow program based on fast decoupled method. The presented method was tested on the multimachine power system. Results: The transmission line loss of the system with and without HVDC was compared. Conclusion: From the simulation results, the HVDC can reduce transmission line loss of power system.

  10. Nonlinear Vibroimpact Characteristics of a Planetary Gear Transmission System

    Directory of Open Access Journals (Sweden)

    Jianxing Zhou

    2016-01-01

    Full Text Available In order to research the vibroimpact characteristics of a planetary gear transmission system under high speed and lightly loaded conditions, a new modeling method is proposed. In the modeling process, linear spring was used to simulate gear mesh elasticity under heavy load cases, and Hertz contact theory was used to calculate the contact force of gear pair under light load cases. Then, effects of the working conditions on the system vibroimpact characteristics are analyzed. The results show that, with input speed growing, the mesh force produced obvious fluctuations on the resonance frequencies of the sun gear and carrier torsion vibration, ring gear’s transverse vibration under the heavy load. Under light load condition, the collision vibration occurs in the gear pair; the changing trend of the contact force shows strongly nonlinear characteristics. The time of mesh-apart in gears pair decreases gradually as the load is increased; until it reaches collision vibration threshold value, the gear pair is no longer mesh-apart. With increasing of the input speed, the time of mesh-apart is decreased gradually; the fluctuation amplitude of contact force shows a linearly increasing trend. The study provides useful theoretical guideline for planetary gear transmission low-noise design.

  11. The Effect Analysis of Strain Rate on Power Transmission Tower-Line System under Seismic Excitation

    OpenAIRE

    Li Tian; Wenming Wang; Hui Qian

    2014-01-01

    The effect analysis of strain rate on power transmission tower-line system under seismic excitation is studied in this paper. A three-dimensional finite element model of a transmission tower-line system is created based on a real project. Using theoretical analysis and numerical simulation, incremental dynamic analysis of the power transmission tower-line system is conducted to investigate the effect of strain rate on the nonlinear responses of the transmission tower and line. The results sho...

  12. Optimisation of power transmission systems using a discrete Tabu Search method

    OpenAIRE

    Connor, Andy M.; Tilley, Derek G.

    2016-01-01

    This paper presents a brief description of the Tabu Search method and shows how it can be applied to two different power transmission systems. Examples are presented from two transmission systems. In the first example a mechanical transmission system is considered. A four bar mechanism is synthesised in order to produce a desired output motion. The second example is a hydrostatic transmission operating under closed loop control in order to maintain a constant operating speed as the loading co...

  13. Applications of exact linearization techniques for steady-state stability enhancement in a weak ac/dc system

    Energy Technology Data Exchange (ETDEWEB)

    Kaprielian, S.; Clements, K. (Dept. of Electrical Engineering, Worcester Polytechnic Inst., Worcester, MA (US)); Turi, J. (Texas Univ., Richardson, TX (United States))

    1992-05-01

    A nonlinear control strategy to improve the steady-state stability of a weak AC/DC power system is presented. The approach described in this paper is based on the extension of feedback linearization techniques to nonlinear descriptor system models. This method produces a nonlinear control strategy which is capable of enhancing system performance for various system operating conditions. This claim is supported with simulation results.

  14. Vector control of three-phase AC machines system development in the practice

    CERN Document Server

    Quang, Nguyen Phung

    2008-01-01

    Covers the area of vector control of 3-phase AC machines, in particular induction motors with squirrel-cage rotor, permanent excited synchronous motors and doubly-fed induction machines. This title summarizes the basic structure of a field-oriented controlled 3-phase AC drive and grid voltage orientated controlled wind power plant.

  15. Development of an in-line filter to prevent intrusion of NO2 toxic vapors into A/C systems

    Science.gov (United States)

    Meneghelli, Barry; Mcnulty, R. J.; Springer, Mike; Lueck, Dale E.

    1995-01-01

    The hypergolic propellant nitrogen tetroxide (N2O4 or NTO) is routinely used in spacecraft launched at Kennedy Space Center (KSC) and Cape Canaveral Air Station (CCAS). In the case of a catastrophic failure of the spacecraft, there would be a release of the unspent propellant in the form of a toxic cloud. Inhalation of this material at downwind concentrations which may be as high as 20 parts per million (ppm) for 30 minutes in duration, may produce irritation to the eyes, nose and respiratory tract. Studies at both KSC and CCAS have shown that the indoor concentrations of N2O4 during a toxic release may range from 1 to 15 ppm and depend on the air change rate (ACR) for a particular building and whether or not the air conditioning (A/C) system has been shut down or left in an operating mode. This project was initiated in order to assess how current A/C systems could be easily modified to prevent personnel from being exposed to toxic vapors. A sample system has been constructed to test the ability of several types of filter material to capture the N2O4 vapors prior to their infiltration into the A/C system. Test results will be presented which compare the efficiencies of standard A/C filters, water wash systems, and chemically impregnated filter material in taking toxic vapors out of the incoming air stream.

  16. Analysis of torsional vibration in an electromechanical transmission system

    Directory of Open Access Journals (Sweden)

    Kai Chen

    2016-06-01

    Full Text Available Aiming at the torsional vibration in the electromechanical transmission system, this article introduces the active vibration method and analyzes the vibration characteristics on the condition of the external excitation, and then, the condition of the permanent magnetic synchronous motor parameter is obtained. In the braking energy recovery working condition, the permanent magnetic synchronous motor is operated in generator mode and is subjected to power control, this cause it to produce negative effect of damping. Negative effect of damping leads to the increasing torsional vibration. Then, the improved power control strategy is introduced to reduce the vibration. Computer simulations are used to demonstrate the active vibration method and the effectiveness of the proposed control strategy, which provides reference for the design of electromechanical systems in the hybrid electrical vehicles.

  17. Dynamic security risk assessment and optimization of power transmission system

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The paper presents a practical dynamic security region (PDSR) based dynamic security risk assessment and optimization model for power transmission system. The cost of comprehensive security control and the influence of uncertainties of power injections are considered in the model of dynamic security risk assessment. The transient stability constraints and uncertainties of power injections can be considered easily by PDSR in form of hyper-box. A method to define and classify contingency set is presented, and a risk control optimization model is given which takes total dynamic insecurity risk as the objective function for a dominant con-tingency set. An optimal solution of dynamic insecurity risk is obtained by opti-mizing preventive and emergency control cost and contingency set decomposition. The effectiveness of this model has been proved by test results on the New Eng-land 10-genarator 39-bus system.

  18. Application of DSP in the image transmission system

    Science.gov (United States)

    Gui, Feng; Wei, LinQi

    2006-05-01

    A scheme to realize static image and video code and decode based on TI DSP chip TMS320C6416 was proposed in this paper, and a reliable image transmission system was developed. According to the application demand, the software has six major modules: (1) initialization of DSP chip and other hardware; (2) video acquisition and input control program; (3) serial port communicating program; (4) RAM storage and communicating program that applies and releases the token-ring; (5) video reconstruct and output control; (6) the major parts of the software, encoding and decoding program, in which wavelet was applied first, then run length coding and Huffman coding were carried out, the image or video could had balance resolution and better visual effect by adaptive processing, in the decoding parts, the reverse operation were executed. After the system line up debugging was carried out, a satisfying result was reached: the comparatively high compression rate, preferable image quality and relatively real-time result.

  19. SURGNET: An Integrated Surgical Data Transmission System for Telesurgery

    Directory of Open Access Journals (Sweden)

    Sriram Natarajan

    2009-01-01

    Full Text Available Remote surgery information requires quick and reliable transmission between the surgeon and the patient site. However, the networks that interconnect the surgeon and patient sites are usually time varying and lossy which can cause packet loss and delay jitter. In this paper we propose SURGNET, a telesurgery system for which we developed the architecture, algorithms and implemented it on a testbed. The algorithms include adaptive packet prediction and buffer time adjustment techniques which reduce the negative effects caused by the lossy and time varying networks. To evaluate the proposed SURGNET system, at the therapist site, we implemented a therapist panel which controls the force feedback device movements and provides image analysis functionality. At the patient site we controlled a virtual reality applet built in Matlab. The varying network conditions were emulated using NISTNet emulator. Our results show that even for severe packet loss and variable delay jitter, the proposed integrated synchronization techniques significantly improve SURGNET performance.

  20. ACS: ALMA Common Software

    Science.gov (United States)

    Chiozzi, Gianluca; Šekoranja, Matej

    2013-02-01

    ALMA Common Software (ACS) provides a software infrastructure common to all ALMA partners and consists of a documented collection of common patterns and components which implement those patterns. The heart of ACS is based on a distributed Component-Container model, with ACS Components implemented as CORBA objects in any of the supported programming languages. ACS provides common CORBA-based services such as logging, error and alarm management, configuration database and lifecycle management. Although designed for ALMA, ACS can and is being used in other control systems and distributed software projects, since it implements proven design patterns using state of the art, reliable technology. It also allows, through the use of well-known standard constructs and components, that other team members whom are not authors of ACS easily understand the architecture of software modules, making maintenance affordable even on a very large project.

  1. Design on AC Filter Sub-bank Maintenance Function in UHVDC System%特高压直流输电交流滤波器小组检修功能的设计

    Institute of Scientific and Technical Information of China (English)

    罗磊; 盛琰; 黄金海; 周玉勇; 崔佳佳

    2016-01-01

    The development of AC filter protection system in ultra⁃high voltage direct current ( UHVDC ) is described in this paper based on the characteristics of UHVDC transmission AC filter and actual requirement of project field. For the AC filter sub⁃bank hard⁃ware features of optical current transformer, by applying the Xuji self⁃developed software platform, AC filter sub⁃bank maintenance function is designed. When the AC filter bank of centralized configuration, sub⁃bank of optical current transformer fault, the realization method of the maintenance function are expounded. AC filter sub⁃bank maintenance function is very necessary for large load operation of UHVDC system, it enhances the reliability of the system.%介绍了特高压直流输电工程交流滤波器保护系统的发展,结合溪浙工程特高压直流输电交流滤波器的特点及工程现场实际运行需求,针对交流滤波器小组光电流互感器的硬件特性,通过许继自主开发的软件平台,设计交流滤波器小组检修功能。阐述交流滤波器大组集中化配置中小组光电流互感器故障时,检修功能的实现方法。交流滤波器小组检修功能,对于大负荷运行的特高压直流系统十分必要,可增强系统的可靠性。

  2. Southeast Alaska intertie dc transmission system: reconnaissance design and cost estimate. Appendix I

    Energy Technology Data Exchange (ETDEWEB)

    1982-11-01

    The detailed costs of the schemes are given in this Appendix. The conceptual designs of the sea electrodes for the schemes are also described. The cost estimates for the electrodes were based on these conceptual designs. A cost comparison of ac and dc transmission for 10 MW from Ketchikan to Tolstoi Bay is given along with an example outlining the procedure for selecting the optimum dc cable size.

  3. Enhancing the Capacity of the AC Distribution System Using DC Interlinks - A Step Towards Future DC Grid

    DEFF Research Database (Denmark)

    Chaudhary, Sanjay; Guerrero, Josep M.; Teodorescu, Remus

    2015-01-01

    The development of distributed generation system and electric vehicles is bound to strain the distribution network. A typical radial distribution feeder suffers from the voltage fluctuation and feeder overload in the presence of a large amount of variable renewable generation. This paper presents...... a concept of enhancing the power handling capacity of distribution networks using dc grid interconnections. Control of both the active and reactive power exchange between the ac feeder and the interconnecting power converter has been proposed for the voltage regulation at the ac feeder terminal. Besides...

  4. Risk measures for power failures in transmission systems

    Science.gov (United States)

    Cassidy, Alex; Feinstein, Zachary; Nehorai, Arye

    2016-11-01

    We present a novel framework for evaluating the risk of failures in power transmission systems. We use the concept of systemic risk measures from the financial mathematics literature with models of power system failures in order to quantify the risk of the entire power system for design and comparative purposes. The proposed risk measures provide the collection of capacity vectors for the components in the system that lead to acceptable outcomes. Keys to the formulation of our measures of risk are two elements: a model of system behavior that provides the (distribution of) outcomes based on component capacities and an acceptability criterion that determines whether a (random) outcome is acceptable from an aggregated point of view. We examine the effects of altering the line capacities on energy not served under a variety of networks, flow manipulation methods, load shedding schemes, and load profiles using Monte Carlo simulations. Our results provide a quantitative comparison of the performance of these schemes, measured by the required line capacity. These results provide more complete descriptions of the risks of power failures than the previous, one-dimensional metrics.

  5. Risk measures for power failures in transmission systems.

    Science.gov (United States)

    Cassidy, Alex; Feinstein, Zachary; Nehorai, Arye

    2016-11-01

    We present a novel framework for evaluating the risk of failures in power transmission systems. We use the concept of systemic risk measures from the financial mathematics literature with models of power system failures in order to quantify the risk of the entire power system for design and comparative purposes. The proposed risk measures provide the collection of capacity vectors for the components in the system that lead to acceptable outcomes. Keys to the formulation of our measures of risk are two elements: a model of system behavior that provides the (distribution of) outcomes based on component capacities and an acceptability criterion that determines whether a (random) outcome is acceptable from an aggregated point of view. We examine the effects of altering the line capacities on energy not served under a variety of networks, flow manipulation methods, load shedding schemes, and load profiles using Monte Carlo simulations. Our results provide a quantitative comparison of the performance of these schemes, measured by the required line capacity. These results provide more complete descriptions of the risks of power failures than the previous, one-dimensional metrics.

  6. Analysis the Performance of Coded WSK-DWDM Transmission System

    Directory of Open Access Journals (Sweden)

    Bobby Barua

    2012-12-01

    Full Text Available Dense Wavelength Division Multiplexing (DWDM is the system with more than eight active wavelengths per fiber. Again high data rates as well as long spans between amplifiers in a chain require high optical power per channel to satisfy the signal to noise ratio (SNR requirements. So the DWDM systems with long repeater-less spans, the simultaneous requirements of high launched power and low dispersion fibers lead to the generation of new waves by four-wave mixing (FWM, which degrades the performance of a multi-channel transmission system. Several methods have been proposed to mitigate the effect of FWM crosstalk. All these works are performed considering only binary WSK scheme. Although M-ary WSK (M>2 schemes have higher spectral efficiency than binary WSK system. Again, the BER performances for M-ary WDM system are not satisfactory with the effect of FWM. Therefore, in this paper we include the effect of FWM on the performance of an M-ary WDM system and try to mitigate the effect by employing the energy efficient convolution code in a normal dispersive fiber as well as in a dispersion shifted fiber (DSF.

  7. Toroidal Continuously Variable Transmission Systems: Terminology and Present Studies

    Directory of Open Access Journals (Sweden)

    Ahmet YILDIZ

    2014-04-01

    Full Text Available The use of continuously variable transmission systems in many different areas such as aerospace, robotics, machinery and automotive industries as an alternative to conventional speed changers with constant ratio becomes widely.Especially in the automotive industry, these systems have been used increasingly, since they enable that internal combustion engines in vehicles run at optimal speeds, and consequently provide considerable fuel savings and therefore lower emission values and also they provide powerful acceleration and quiet working. CVT systems have several constructive variants such as belted, chained, balled, toroidal etc. In this paper, toroidal CVT systems based on elastohydrodynamic principles are concerned with, and fundamental works of last two decades in this field are reviewed. However, the relevant terminology and dynamics along with the control of these systems are briefly treated for better understanding of the literature mentioned. Attention is drawn to the lack of some significant issues in present research works, and potential future works are pointed out. This paper, to the authors’ knowledge, will be the first review on toroidal CVT systems in Turkish literature

  8. 77 FR 26275 - Bonneville Power Administration; Montana-to-Washington Transmission System Upgrade Project EIS

    Science.gov (United States)

    2012-05-03

    ... Bonneville Power Administration; Montana-to-Washington Transmission System Upgrade Project EIS AGENCY...``''sts for long-term transmission service. During the NOS process, utilities and power generators (including wind generators and power marketers) requested the use of BPA's transmission system to...

  9. The vibration research of the AC dipole-girder system for CSNS/RCS

    CERN Document Server

    Renhong, Liu; Huamin, Qu; Ling, Kang; Motuo, Wang; Guangyuan, Wang; Haijing, Wang

    2013-01-01

    China spallation neutron source(CSNS) is a high intensity proton accelerator based facility, and its accelerator complex includes two main parts: an H- linac and a rapid cycling synchrotron(RCS). The rcs accumulates the 80MeV proton beam, and accelerates it to 1.6GeV, with a repetition rate of 25 Hz. The AC dipole of the RCS is operated at a 25Hz sinusoidal alternating current which causes severe vibration. The vibration will influence the long-term safety and reliable operation of the magnet. The dipole magnet of RCS is active vibration equipment which is different with ground vibration accelerator. It is very important to design and research the dynamic characteristic of the dipole-girder system. This paper takes the dipole and girder as a specific model system, a method for researching the dynamic characteristic of the system is put forward by combining theoretical calculation with experimental testing. The ansys simulation method plays a very important role in the girder structure design stage. With the m...

  10. Shunt capacitors for a.c. power systems having a rated voltage above 1000 V - Part 1: General

    CERN Document Server

    International Electrotechnical Commission. Geneva

    2005-01-01

    This part of IEC 60871 is applicable to both capacitor units and capacitor banks intended to be used, particularly, for power-factor correction of a.c. power systems having a rated voltage above 1 000 V and frequencies of 15 Hz to 60 Hz. This part of IEC 60871 also applies to capacitors intended for use in power filter circuits.

  11. 厂外排水管道交流稳态干扰防护设计%Protection Design against AC Steady-state Interference for Water Pipeline near High-voltage Transmission Lines

    Institute of Scientific and Technical Information of China (English)

    程明; 牟华; 黄春蓉; 张平

    2013-01-01

    AC steady-state interference may affect the water pipeline near high-voltage transmission lines. Referring to some related standards, the mitigation objective and protection effect of the AC interference were analyzed, and the Right of Way (ROW) package was used to build modeling and calculation around the mitigation. The calculation results can guide the engineering design.%高压输电线路附近的厂外排水管道可能面临交流稳态干扰影响.结合相关标准要求,对交流干扰缓解目标和防护效果进行探讨分析,并利用自动计算软件包(ROW)分别对缓解前后进行建模计算分析.计算分析结果可以指导工程设计.

  12. Transmission of multiple system atrophy prions to transgenic mice.

    Science.gov (United States)

    Watts, Joel C; Giles, Kurt; Oehler, Abby; Middleton, Lefkos; Dexter, David T; Gentleman, Steve M; DeArmond, Stephen J; Prusiner, Stanley B

    2013-11-26

    Prions are proteins that adopt alternative conformations, which become self-propagating. Increasing evidence argues that prions feature in the synucleinopathies that include Parkinson's disease, Lewy body dementia, and multiple system atrophy (MSA). Although TgM83(+/+) mice homozygous for a mutant A53T α-synuclein transgene begin developing CNS dysfunction spontaneously at ∼10 mo of age, uninoculated TgM83(+/-) mice (hemizygous for the transgene) remain healthy. To determine whether MSA brains contain α-synuclein prions, we inoculated the TgM83(+/-) mice with brain homogenates from two pathologically confirmed MSA cases. Inoculated TgM83(+/-) mice developed progressive signs of neurologic disease with an incubation period of ∼100 d, whereas the same mice inoculated with brain homogenates from spontaneously ill TgM83(+/+) mice developed neurologic dysfunction in ∼210 d. Brains of MSA-inoculated mice exhibited prominent astrocytic gliosis and microglial activation as well as widespread deposits of phosphorylated α-synuclein that were proteinase K sensitive, detergent insoluble, and formic acid extractable. Our results provide compelling evidence that α-synuclein aggregates formed in the brains of MSA patients are transmissible and, as such, are prions. The MSA prion represents a unique human pathogen that is lethal upon transmission to Tg mice and as such, is reminiscent of the prion causing kuru, which was transmitted to chimpanzees nearly 5 decades ago.

  13. Hybrid energy harvesting/transmission system for embedded devices

    Science.gov (United States)

    Hehr, Adam; Park, Gyuhae; Farinholt, Kevin

    2012-04-01

    In most energy harvesting applications the need for a reliable long-term energy supply is essential in powering embedded sensing and control electronics. The goal of many harvesters is to extract energy from the ambient environment to power hardware; however in some applications there may be conditions in which the harvester's performance cannot meet all of the demands of the embedded electronics. One method for addressing this shortfall is to supplement harvested power through the transmission of wireless energy, a concept that has successfully been demonstrated by the authors in previous studies. In this paper we present our findings on the use of a single electromagnetic coil to harvest kinetic energy in a solenoid configuration, as well as background and directed wireless energy in the 2.4 GHz radio frequency (RF) bands commonly used in WiFi and cellular phone applications. The motivation for this study is to develop a compact energy harvester / receiver that conserves physical volume, while providing multi-modal energy harvesting capabilities. As with most hybrid systems there are performance trade-offs that must be considered when capturing energy from different physical sources. As part of this paper, many of the issues related to power transmission, physical design, and potential applications are addressed for this device.

  14. Diagnostics of power transmissions system with tooth gear

    Directory of Open Access Journals (Sweden)

    Grzegorz WOJNAR

    2008-01-01

    Full Text Available This paper presents results of laboratory tests that were aimed at detecting early stages of various faults in toothed wheels by measurement and analysis of transverse vibration speed of the transmission gear shafts. In experimental investigation, cracking of the root tooth and chipping of the tooth were detected. The laser vibrometer Ometron VH300+ was used for non-contact measurement of shaft transversal vibration speed. Gear vibrations were recorded in selected points of gear housing and gear shafts at different speeds and gear loads. Results were analyzed and compared but in this paper is presented only selected examples. This paper shows that on the basis of the transverse vibration speed of transmission gear shafts, it is possible to detect defects at an earlier stage than on the basis of the housing vibration accelerations. In the case of measuring gear shaft vibration velocity, the way of the signal generated by the defect of a gear wheel (or bearing is shortened as well as the influence of composed transmittance of the bearing-gear housing system is eliminated. WV time-frequency analysis and complex continuous wavelet transformations were used for detection. The authors introduced a measure of local tooth damage, which was proportional to the size of damage. The results of research presented in this paperconfirmed that the defect's measure is very sensitive to the development of teeth faults.

  15. MODES OF OPERATION OF THE SYSTEM OF TRACTION POWER AC USING REACTIVE POWER COMPENSATION DEVICES

    Directory of Open Access Journals (Sweden)

    I.V. Domanskyi

    2015-06-01

    Full Text Available The paper presents a systematic analysis of existing methods of reactive power compensation. The study of operating modes of the systems external and traction power supply is carried out. The methodology for selecting promising compensation schemes and energy-saving in the traction networks AC electrified railway lines is offered. The comparative evaluation of prospective controlled compensation devices shows that use of seamlessly adjustable devices with unregulated condensing the battery and with parallel translator regulated with thyristor unit and with filters to reduce harmonics bond to the large capital investments. For traction networks of domestic railways payback period is more than 10-15 years. The most promising for traction power supply today is a stepwise adjustable devices of reactive power compensation. For the efficient allocation of investments in programs and projects of modernization of system traction power supply developed by the methodology of selecting parameters and places placement devices transverse compensation in the system traction power supply, which is based on the use of software systems with imitation of interconnected instant circuits moving loads of electric rolling stock. Based on the results of multiple calculations full factor experiment when simulating work of the systems traction power supply during the day marked the most influencing factors on energy-saving in process freight on electric traction and established the extent of their influence. These include the overflows of power, the resistance of traction network, reactive power compensation, power supply circuits and the organization of trains. Innovative technologies energy-saving railways from positions of consideration their close connection with the systems external power supply are proposed.

  16. Economically adapted transmission systems in open access schemes -- Application of genetic algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Rudnick, H.; Palma, R.; Cura, E.; Silva, C. [Pontificia Univ. Catolica de Chile, Santiago (Chile). Dept. de Ingenieria Electrica

    1996-08-01

    A dynamic transmission planning methodology using a genetic algorithm is formulated for the purpose of determining an economically adapted electric transmission system in a deregulated open access environment. Transmission investment sensitivity information linked to short term marginal income is used. A computer program is developed and applied to obtain a long range adapted transmission grid for the Chilean electrical system. Two open access pricing methodologies are evaluated in a spot price framework, as applied to the adapted grid over the time horizon.

  17. Forming the Calculated Dynamic Transmission Systems of Wheeled Vehicles

    Directory of Open Access Journals (Sweden)

    A. B. Fominykh

    2017-01-01

    Full Text Available To calculate dynamic loading of transmission parts of wheeled vehicles, it is necessary to build up the appropriate calculated dynamic systems and determine their inertial, elastic, and damping parameters.The initial point of this process is to form an initial dynamic system. Hereafter, to cut the time of computations there is a need to reduce the number of masses of this system, and sometimes simplify its structure. The main requirement to be fulfilled in this case is that the calculated dynamical system is to be equivalent to the initial one (in terms of similarity of the vibrational process characteristics in these systems, i.e., the frequencies and modes of oscillations of both systems, their amplitude-frequency characteristics. This is possible when the energy characteristics of the corresponding systems are equal, i.e. their kinetic and potential energies, dissipative functions, and external force energies.Usually, when forming the initial and calculated dynamic systems, all types of friction are reduced to a linearly viscous one. However, it disables us to investigate the motion of these systems if there is an arbitrary, in particular, poly-harmonic action (for example, on the side of the internal combustion engine, since in this case the linear friction coefficients given will depend on the frequency and amplitude of the oscillations.The paper is aimed at determining the equivalent parameters of calculated dynamic systems of wheeled vehicles, including the dissipative parameters for the general case of friction.On the basis of energy principles, the expressions are obtained to determine the equivalent inertial, elastic, and damping parameters of the calculated dynamical systems of wheeled vehicles when the structure is changed and the number of masses of the system is decreased. The presented technique enables us to investigate the motion of these systems under arbitrary, including poly-harmonic, action on the system, using the

  18. Power Transmission from Large Offshore Wind Farms

    DEFF Research Database (Denmark)

    Pedersen, Jørgen Kaas

    1999-01-01

    for transmitting the power can be by DC. At the moment it is possible to build self-commutating DC/AC-inverters up to about 150 kV. This paper will show a concept to a solution for a wind farm and a transmission system based on synchronous generators or a powerformer® with a rated voltage of 50 kV. The AC power...

  19. On multiuser switched diversity transmission for spectrum sharing systems

    KAUST Repository

    Qaraqe, Marwa

    2012-01-01

    In this paper, we develop multiuser access schemes for spectrum sharing systems whereby secondary users share the spectrum with primary users. In particular, we devise two schemes for selecting the user among those that satisfy the interference constraints and achieve an acceptable signal-to-noise ratio (SNR) level. The first scheme selects the user with the maximum SNR at the receiver, whereas in the second scheme the users are scanned in a sequential manner until an acceptable user is found. In addition, we consider two power adaptive settings. In the on/off power adaptive setting, the users transmit based on whether the interference constraint is met or not while in the full power adaptive setting, the users vary their transmission power to satisfy the interference constraint. Finally, we present numerical results of our proposed algorithms where we show the trade-off between the average spectral efficiency and average feedback load of both schemes. © 2012 ICST.

  20. Vibration and noise analysis of a gear transmission system

    Science.gov (United States)

    Choy, F. K.; Qian, W.; Zakrajsek, J. J.; Oswald, F. B.

    1993-01-01

    This paper presents a comprehensive procedure to predict both the vibration and noise generated by a gear transmission system under normal operating conditions. The gearbox vibrations were obtained from both numerical simulation and experimental studies using a gear noise test rig. In addition, the noise generated by the gearbox vibrations was recorded during the experimental testing. A numerical method was used to develop linear relationships between the gearbox vibration and the generated noise. The hypercoherence function is introduced to correlate the nonlinear relationship between the fundamental noise frequency and its harmonics. A numerical procedure was developed using both the linear and nonlinear relationships generated from the experimental data to predict noise resulting from the gearbox vibrations. The application of this methodology is demonstrated by comparing the numerical and experimental results from the gear noise test rig.

  1. Vibration Signature Analysis of a Faulted Gear Transmission System

    Science.gov (United States)

    Choy, F. K.; Huang, S.; Zakrajsek, J. J.; Handschuh, R. F.; Townsend, D. P.

    1996-01-01

    A comprehensive procedure in predicting faults in gear transmission systems under normal operating conditions is presented. Experimental data were obtained from a spiral bevel gear fatigue test rig at NASA/Lewis. Time-synchronous-averaged vibration data were recorded throughout the test as the fault progressed from a small single pit to severe pitting over several teeth, and finally tooth fracture. A numerical procedure based on the Wigner-Ville distribution was used to examine the time-averaged vibration data. Results from the Wigner-Ville procedure are compared to results from a variety of signal analysis techniques that include time-domain analysis methods and frequency analysis methods. Using photographs of the gear tooth at various stages of damage, the limitations and accuracy of the various techniques are compared and discussed. Conclusions are drawn from the comparison of the different approaches as well as the applicability of the Wigner-Ville method in predicting gear faults.

  2. Gas data transmission system by satellite telephone; Systeme de transmission de donnees sur le gaz utilisant le telephone par satellite

    Energy Technology Data Exchange (ETDEWEB)

    Ogasawara, S.; Tanji, A. [Dengineer Co., Ltd (Japan); Akiyama, S. [Buyo Gas Company (Japan)

    2000-07-01

    Dengineer Co., Ltd. and Buyo Gas Co., Ltd. had been developing and using the data and alarm transmission system by public telephone since 1984, that was first practical use in Japan. It is very important for business management that adjusts the production value of gas by measuring gas pressures in each governor. Also, it is indispensable to know the accident of gas leakage or abnormal gas pressure quickly. But this convenient system is not spread yet in Japanese market cause of the following reasons. - Take time and cost for installation of terminal station. - Terminal station is apt to damage by thunder. - Big disaster must stop working this system. In order to solve those problems, we have developed and tested the system organized of the satellite telephone system and solar cells for power. This system will be very useful for wide place, not only Japanese market but also the area, which has no electricity and phone. Also, it will be convenient for international rescue as is able to access it from the foreign countries. (authors)

  3. Transmission imaging for integrated PET-MR systems.

    Science.gov (United States)

    Bowen, Spencer L; Fuin, Niccolò; Levine, Michael A; Catana, Ciprian

    2016-08-07

    Attenuation correction for PET-MR systems continues to be a challenging problem, particularly for body regions outside the head. The simultaneous acquisition of transmission scan based μ-maps and MR images on integrated PET-MR systems may significantly increase the performance of and offer validation for new MR-based μ-map algorithms. For the Biograph mMR (Siemens Healthcare), however, use of conventional transmission schemes is not practical as the patient table and relatively small diameter scanner bore significantly restrict radioactive source motion and limit source placement. We propose a method for emission-free coincidence transmission imaging on the Biograph mMR. The intended application is not for routine subject imaging, but rather to improve and validate MR-based μ-map algorithms; particularly for patient implant and scanner hardware attenuation correction. In this study we optimized source geometry and assessed the method's performance with Monte Carlo simulations and phantom scans. We utilized a Bayesian reconstruction algorithm, which directly generates μ-map estimates from multiple bed positions, combined with a robust scatter correction method. For simulations with a pelvis phantom a single torus produced peak noise equivalent count rates (34.8 kcps) dramatically larger than a full axial length ring (11.32 kcps) and conventional rotating source configurations. Bias in reconstructed μ-maps for head and pelvis simulations was  ⩽4% for soft tissue and  ⩽11% for bone ROIs. An implementation of the single torus source was filled with (18)F-fluorodeoxyglucose and the proposed method quantified for several test cases alone or in comparison with CT-derived μ-maps. A volume average of 0.095 cm(-1) was recorded for an experimental uniform cylinder phantom scan, while a bias of  <2% was measured for the cortical bone equivalent insert of the multi-compartment phantom. Single torus μ-maps of a hip implant phantom showed significantly

  4. Transmission imaging for integrated PET-MR systems

    Science.gov (United States)

    Bowen, Spencer L.; Fuin, Niccolò; Levine, Michael A.; Catana, Ciprian

    2016-08-01

    Attenuation correction for PET-MR systems continues to be a challenging problem, particularly for body regions outside the head. The simultaneous acquisition of transmission scan based μ-maps and MR images on integrated PET-MR systems may significantly increase the performance of and offer validation for new MR-based μ-map algorithms. For the Biograph mMR (Siemens Healthcare), however, use of conventional transmission schemes is not practical as the patient table and relatively small diameter scanner bore significantly restrict radioactive source motion and limit source placement. We propose a method for emission-free coincidence transmission imaging on the Biograph mMR. The intended application is not for routine subject imaging, but rather to improve and validate MR-based μ-map algorithms; particularly for patient implant and scanner hardware attenuation correction. In this study we optimized source geometry and assessed the method’s performance with Monte Carlo simulations and phantom scans. We utilized a Bayesian reconstruction algorithm, which directly generates μ-map estimates from multiple bed positions, combined with a robust scatter correction method. For simulations with a pelvis phantom a single torus produced peak noise equivalent count rates (34.8 kcps) dramatically larger than a full axial length ring (11.32 kcps) and conventional rotating source configurations. Bias in reconstructed μ-maps for head and pelvis simulations was  ⩽4% for soft tissue and  ⩽11% for bone ROIs. An implementation of the single torus source was filled with 18F-fluorodeoxyglucose and the proposed method quantified for several test cases alone or in comparison with CT-derived μ-maps. A volume average of 0.095 cm-1 was recorded for an experimental uniform cylinder phantom scan, while a bias of  translation of the patient table to perform complete tomographic sampling, generated highly quantitative measured μ-maps and is expected to produce images with

  5. An AC modulated near infrared gain calibration system for a "Violin-Mode" transimpedance amplifier, intended for advanced LIGO suspensions.

    Science.gov (United States)

    Lockerbie, N A; Tokmakov, K V

    2016-07-01

    The background to this work was a prototype shadow sensor, which was designed for retro-fitting to an advanced LIGO (Laser Interferometer Gravitational wave Observatory) test-mass/mirror suspension, in which a 40 kg test-mass/mirror is suspended by four approximately 600 mm long by 0.4 mm diameter fused-silica suspension fibres. The shadow sensor comprised a LED source of Near InfraRed (NIR) radiation, and a "tall-thin" rectangular silicon photodiode detector, which together were to bracket the fibre under test. The photodiode was positioned so as to be sensitive (primarily) to transverse "Violin-Mode" vibrations of such a fibre, via the oscillatory movement of the shadow cast by the fibre, as this moved across the face of the detector. In this prototype shadow sensing system the photodiode was interfaced to a purpose-built transimpedance amplifier, this having both AC and DC outputs. A quasi-static calibration was made of the sensor's DC responsivity, i.e., incremental rate of change of output voltage versus fibre position, by slowly scanning a fused-silica fibre sample transversely through the illuminating beam. The work reported here concerns the determination of the sensor's more important AC (Violin-Mode) responsivity. Recognition of the correspondence between direct AC modulation of the source, and actual Violin-Mode signals, and of the transformative role of the AC/DC gain ratio for the amplifier, at any modulation frequency, f, resulted in the construction of the AC/DC calibration source described here. A method for determining in practice the transimpedance AC/DC gain ratio of the photodiode and amplifier, using this source, is illustrated by a specific numerical example, and the gain ratio for the prototype sensing system is reported over the frequency range 1 Hz-300 kHz. In fact, a maximum DC responsivity of 1.26 kV.m(-1) was measured using the prototype photodiode sensor and amplifier discussed here. Therefore, the measured AC/DC transimpedance gain

  6. Band gap transmission in periodic bistable mechanical systems

    Science.gov (United States)

    Frazier, Michael J.; Kochmann, Dennis M.

    2017-02-01

    We theoretically and numerically investigate the supratransmission phenomenon in discrete, nonlinear systems containing bistable elements. While linear waves cannot propagate within the band gaps of periodic structures, supratransmission allows large-amplitude waves to transmit energy through the band gap. For systems lacking bistability, the threshold amplitude for such energy transmission at a given frequency in the linear band gap is fixed. We show that the topological transitions due to bistability provide an avenue for switching the threshold amplitude between two well-separated values. Moreover, this versatility is achieved while leaving the linear dispersion properties of the system essentially unchanged. Interestingly, the behavior changes when an elastic chain is coupled to bistable resonators (in an extension of the well-studied linear locally resonant metamaterials). Here, we show that a fraction of the injected energy is confined near the boundary due to the resonators, providing a means of regulating the otherwise unrestrained energy flow due to supratransmission. Together, the results illustrate new means of controlling nonlinear wave propagation and energy transport in systems having multi-stable elements.

  7. Self-powered system with wireless data transmission.

    Science.gov (United States)

    Hu, Youfan; Zhang, Yan; Xu, Chen; Lin, Long; Snyder, Robert L; Wang, Zhong Lin

    2011-06-08

    We demonstrate the first self-powered system driven by a nanogenerator (NG) that works wirelessly and independently for long-distance data transmission. The NG was made of a free cantilever beam that consisted of a five-layer structure: a flexible polymer substrate, ZnO nanowire textured films on its top and bottom surfaces, and electrodes on the surfaces. When it was strained to 0.12% at a strain rate of 3.56% S(-1), the measured output voltage reached 10 V, and the output current exceeded 0.6 μA (corresponding power density 10 mW/cm(3)). A system was built up by integrating a NG, rectification circuit, capacitor for energy storage, sensor, and RF data transmitter. Wireless signals sent out by the system were detected by a commercial radio at a distance of 5-10 m. This study proves the feasibility of using ZnO nanowire NGs for building self-powered systems, and its potential application in wireless biosensing, environmental/infrastructure monitoring, sensor networks, personal electronics, and even national security.

  8. Visualization of Available Power Transfer Capability in a Transmission System Using Morphological Techniques

    Directory of Open Access Journals (Sweden)

    S. U. Prabha

    2009-01-01

    Full Text Available A morphological decimation technique has been proposed and implemented to analyze the available power transfer capability in a transmission power network. The method creates a graphical image of the power network with thickness of the lines proportional to their respective rated megavolt ampere (MVA capacity. Based on ac load flow solution, another image was created to represent the power flow in Megawatt (MW between the buses. Proper scaling procedure has been discussed for the construction of graphical images. The novelty of this research lies in the application of mathematical morphological techniques for decimating the created images. The image created for the MW capacities of the power lines were decimated into categories and grouped into different colors for better visualization. The multi-color image is superimposed on the input image which is created for the MVA capacity of the network. The proposed method has been tested on an IEEE test system. The results from the present approach can help the planner and operator in a power station, to get a better visualization of the power network. This is the first time this kind of multi-color visualization is presented and it can be used to find the optimal path for power transfer from one bus to another.

  9. Component tests for the ITER Ion Cyclotron Transmission Line and Matching System - Status and Plans

    Science.gov (United States)

    Goulding, R. H.; McCarthy, M. P.; Deibele, C. E.; Rasmussen, D. A.; Swain, D. W.; Barber, G. C.; Campbell, I. H.; Gray, S. L.; Moon, R. L.; Pesavento, P. V.; Sanabria, R. M.; Fredd, E.; Greenough, N.; Kung, C.

    2015-11-01

    New Z0 = 50 Ω gas-cooled component designs for the ITER Ion Cyclotron Heating and Current Drive System have been successfully tested at high RF power levels. They include two types featuring spoke-ring assembly (SRA) inner conductor supports: 20° elbows, and variable length assembly bellows, both achieving RF voltages > 35 kV peak, and currents ~ 760 A peak during quasi-steady state operation. The SRA utilizes mechanically preloaded fused quartz spokes, increasing lateral load handling capability. Components with SRA supports have been seismically tested, with no variation in low power electrical performance detected after testing. A 3 MW four-port switch has also been successfully tested at high RF power, and tests of a 6 MW hybrid power splitter are planned in the near future. Latest results will be presented. Plans for arc localization tests in a 60 m SRA transmission line run, and RF tests of Z0 = 50 Ω and Z0 = 20 Ω matching components with water-cooled inner conductors will also be discussed. This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy.

  10. Simulation Analysis on Electrical Characteristics of 1 000 kV AC Double-Circuit Transmission Lines on the Same Tower%1000kV交流同塔双回输电线路的电气特性仿真分析

    Institute of Scientific and Technical Information of China (English)

    杜丁香; 周泽昕; 李岩军; 李仲青

    2011-01-01

    为研究1000kV同塔双回输电对继电保护装置的影响,需要首先对其电气特性进行深入研究.根据工程设计参数,在实时数字仿真器中建立仿真系统,进行有关模拟试验,将其主要电气特性与1000 kV单回输电系统和500 kV同塔双回输电系统进行比较.主要针对互感的影响、谐波含量、非周期分量衰减时间、充电电流、恢复电压、高阻接地故障电流水平等进行分析和比较.从研究对继电保护装置影响的角度,分析特高压同塔双回输电系统的电气特征及其对保护装置产生的影响.特高压同塔双回线间的互感影响接地距离保护范围的准确性,故障电流中的非整数次谐波及衰减非周期分量影响继电保护装置的速动性,经高阻接地故障时,故障电流减小影响继电保护装置的灵敏性.继电保护生产厂商需针对这些新电气特征进行深入研究和改进.%To analyze the influences of the 1 000 kV AC double-circuit transmission line on the same tower on the protective relayings, a simulation system is built in the real-time digital simulator to perform related simulative tests.The principal electrical characteristics of above-mentioned transmission line are compared with those of 1 000 kV AC single-circuit transmission line and those of 500 kV double-circuit transmission line on the same tower respectively.The analysis and comparison of following electrical characteristics in the above-mentioned three kinds of ultra high voltage AC transmission lines, i.e., the influence of mutual inductance, harmonic content, attenuation time of aperiodic component, charging current, restore voltage and current level under high resistance grounding fault, are performed. In the viewpoint of the influences on protective relayings, the electrical characteristics of 1 000 kV AC double-circuit transmission line on the same tower as well as its influences on protection devices are analyzed. The mutual inductance

  11. 直流系统对含大规模风电场交流系统的影响%The Impact of DC system on AC system that containing large-scale wind farm

    Institute of Scientific and Technical Information of China (English)

    任华; 刁海勇; 陈立汉; 常喜强; 王维庆; 张东明; 杨皓宇; 郭爱平

    2016-01-01

    With the Northwest 750kV grid built and Xinjiang “Bundled Wind & Fire”DC transmission imple‐ment ,Xinjiang Power Grid has formed a AC/DC system .In order to analyze that D‐PMSG wind farm connect‐ing grid and exporting by HVDC on the impact of AC/DC system ,aim to the transmission program that trans‐port the power after the large D‐PMSG wind farm connect to grid ,construct the network topology of the sys‐tem ,establish the mathematical model of the Large‐scale D‐PMSG wind farm and HVDC system .Based on PSCAD /EM TDC ,simulate and analysis:DC system influence on communication system containing large‐scale wind farms ,and different control mode ,different dc system reactive power compensation capacity ,dc fault ,proportion of ac/dc to ac system ,and the effect on the stability of the wind farm .%随着西北网750 kV主网的建成及新疆“风火打捆”直流外送的实施,新疆电网已形成了交直流混联的系统。为了分析直流系统对大规模风电场交流系统的影响,针对大规模直驱风电场与火力发电厂打捆并网后直流外送的输电方案,构建了含交直流系统的网络拓扑结构,建立了大规模直驱风电场及直流输电系统的数学模型。基于PSCAD/EM TDC软件,仿真并分析了:直流系统对含大规模风电场的交流系统的影响,以及直流系统不同的控制方式、不同的无功补偿容量、直流故障、交直流比例对交流系统及风电场稳定性的影响。

  12. The Diagnostic System of A – 604 Automatic Transmission

    Directory of Open Access Journals (Sweden)

    Czaban Jaroslaw

    2014-09-01

    Full Text Available Automatic gearbox gains increasing popularity in Europe. Little interest in diagnosis of such type of transmission in Poland results from the fact of small share in the whole market of operated cars, so there is a lack of availability of special diagnostic devices. These factors cause issues of expensive repairs, often involving a replacement of subassembly to new or aftermarket one. To a small extent some prophylactic diagnostic tests are conducted, which can eliminate future gearbox system failures. In the paper, the proposition of diagnostic system of popular A - 604 gearbox was presented. The authors are seeking for the possibility of using such type of devices to functional elaboration of gearboxes after renovation. The built system pursues the drive of the researched object, connected with simulated load, where special controller, replacing the original one, is responsible for controlling gearbox operation. This way is used to evaluate the mechanic and hydraulic parts' state. Analysis of signal runs, registered during measurements lets conclude about operation correctness, where as comparison with stock data verifies the technical state of an automatic gearbox.

  13. Transmissibility of the monkeypox virus clades via respiratory transmission: investigation using the prairie dog-monkeypox virus challenge system.

    Directory of Open Access Journals (Sweden)

    Christina L Hutson

    Full Text Available Monkeypox virus (MPXV is endemic within Africa where it sporadically is reported to cause outbreaks of human disease. In 2003, an outbreak of human MPXV occurred in the US after the importation of infected African rodents. Since the eradication of smallpox (caused by an orthopoxvirus (OPXV related to MPXV and cessation of routine smallpox vaccination (with the live OPXV vaccinia, there is an increasing population of people susceptible to OPXV diseases. Previous studies have shown that the prairie dog MPXV model is a functional animal model for the study of systemic human OPXV illness. Studies with this model have demonstrated that infected animals are able to transmit the virus to naive animals through multiple routes of exposure causing subsequent infection, but were not able to prove that infected animals could transmit the virus exclusively via the respiratory route. Herein we used the model system to evaluate the hypothesis that the Congo Basin clade of MPXV is more easily transmitted, via respiratory route, than the West African clade. Using a small number of test animals, we show that transmission of viruses from each of the MPXV clade was minimal via respiratory transmission. However, transmissibility of the Congo Basin clade was slightly greater than West African MXPV clade (16.7% and 0% respectively. Based on these findings, respiratory transmission appears to be less efficient than those of previous studies assessing contact as a mechanism of transmission within the prairie dog MPXV animal model.

  14. An electrochemical study of corrosion protection by primer-topcoat systems on 4130 steel with ac impedance and dc methods

    Science.gov (United States)

    Mendrek, M. J.; Higgins, R. H.; Danford, M. D.

    1988-01-01

    To investigate metal surface corrosion and the breakdown of metal protective coatings, the ac impedance method is applied to six systems of primer coated and primer topcoated 4130 steel. Two primers were used: a zinc-rich epoxy primer and a red lead oxide epoxy primer. The epoxy-polyamine topcoat was used in four of the systems. The EG and G-PARC Model 368 ac impedance measurement system, along with dc measurements with the same system using the polarization resistance method, were used to monitor changing properties of coated 4230 steel disks immersed in 3.5 percent NaCl solutions buffered at pH 5.4 over periods of 40 to 60 days. The corrosion system can be represented by an electronic analog called an equivalent circuit consisting of resistors and capacitors in specific arrangements. This equivalent circuit parallels the impedance behavior of the corrosion system during a frequency scan. Values for the resistors and capacitors, that can be assigned in the equivalent circuit following a least-squares analysis of the data, describe changes that occur on the corroding metal surface and in the protective coatings. Two equivalent circuits have been determined that predict the correct Bode phase and magnitude of the experimental sample at different immersion times. The dc corrosion current density data are related to equivalent circuit element parameters. Methods for determining corrosion rate with ac impedance parameters are verified by the dc method.

  15. Response prediction techniques and case studies of a path blocking system based on Global Transmissibility Direct Transmissibility method

    Science.gov (United States)

    Wang, Zengwei; Zhu, Ping; Zhao, Jianxuan

    2017-02-01

    In this paper, the prediction capabilities of the Global Transmissibility Direct Transmissibility (GTDT) method are further developed. Two path blocking techniques solely using the easily measured variables of the original system to predict the response of a path blocking system are generalized to finite element models of continuous systems. The proposed techniques are derived theoretically in a general form for the scenarios of setting the response of a subsystem to zero and of removing the link between two directly connected subsystems. The objective of this paper is to verify the reliability of the proposed techniques by finite element simulations. Two typical cases, the structural vibration transmission case and the structure-borne sound case, in two different configurations are employed to illustrate the validity of proposed techniques. The points of attention for each case have been discussed, and conclusions are given. It is shown that for the two cases of blocking a subsystem the proposed techniques are able to predict the new response using measured variables of the original system, even though operational forces are unknown. For the structural vibration transmission case of removing a connector between two components, the proposed techniques are available only when the rotational component responses of the connector are very small. The proposed techniques offer relative path measures and provide an alternative way to deal with NVH problems. The work in this paper provides guidance and reference for the engineering application of the GTDT prediction techniques.

  16. Study on New Concatenated Code in WDM Optical Transmission Systems

    Institute of Scientific and Technical Information of China (English)

    YUAN Jian-guo; JIANG Ze; MAO You-ju; YE Wen-wei

    2007-01-01

    A new concatenated code of RS(255,239)+BCH(2 040,1 930) code to be suitable for WDM optical transmission systems is proposed.The simulation results show that this new concatenated code,compared with the RS(255,239)+CSOC(k0/n0=6/7,J=8) code in ITU-T G.75.1,has a lower redundancy and better error-correction performance,furthermore,its net coding gain(NCG) is respectively 0.46 dB,0.43 dB more than that of RS(255,239)+CSOC(k0/n0 =6/7,J=8) code and BCH(3 860,3 824)+BCH(2 040,1 930) code in ITU-T G.75.1 at the third iteration for the bit error rate(BER) of 10-12.Therefore,the new super forward error correction(Super-FEC) concatenated code can be better used in ultra long-haul,ultra large-capacity and ultra high-speed WDM optical communication systems.

  17. Statistics and Analysis on Reliability of HVDC Transmission Systems of SGCC

    Institute of Scientific and Technical Information of China (English)

    Xu

    2010-01-01

    Reliability level of HVDC power transmission systems becomes an important factor impacting the entire power grid. The author analyzes the reliability of HVDC power transmission systems owned by SGCC since 2003 in respect of forced outage times, forced energy unavailability, scheduled energy unavailability and energy utilization efficiency. The results show that the reliability level of HVDC power transmission systems owned by SGCC is improving. By analyzing different reliability indices of HVDC power transmission system, the maximum asset benefits of power grid can be achieved through building a scientific and reasonable reliability evaluation system.

  18. 47 CFR 73.644 - Subscription TV transmission systems.

    Science.gov (United States)

    2010-10-01

    ... adjacent channel stations must not increase over that resulting from the transmission of programming with..., of Subpart H of Part 15 of the FCC Rules for TV Interface Devices. (c) Prior to commencing the transmission of encoded subscription programming, the licensee or permittee of a TV broadcast or low power...

  19. Audible noise predicting formulas and reduction measures for 1 000 kV UHV AC transmission lines%1000 kV交流输电线路噪声的计算模式和减缓措施

    Institute of Scientific and Technical Information of China (English)

    罗超; 查智明; 姚为方

    2015-01-01

    Several audible corona noise predicting formulas of UHA transmission lines,founded by BPA from the U. S. A. ,ENEL from Italy and EPRI from China etc. ,were introduced. Based on the conductor parameter of Huannan-Shanghai 1 000 kV UHV AC double-circuit transmission line,four formulas were presented for pre-dicting the audible noise of the same type transmission lines exactly. The factors resulting in audible noise of UHV AC transmission line are analyzed,including the structure,design and construction of the transmission line, as wel as the atmosphere and environments. The measures to reduce audible noise of transmission line were summed up,and such engineering solutions to reduce the audible noise as increasing the diameter of bundled conductors,increasing the bundle numbers and changing the interval between bundled conductors are consid-ered applicable. Some preventive suggestions ale provided in the hope of supporting on-site operation data for designs of 1000kV UHVAC transmission lines,operation and maintenance.%介绍了几家国内外研究机构建立的用来计算预测输电线路电晕可听噪声的模式,针对皖电东送淮南至上海1000 kV特高压交流示范工程输电线路的实际参数,建立了相应的计算公式,可以较为准确的预测该类型输电线路可听噪声的大小;交流输电线路电晕产生可听噪声的影响因素众多,根据是否可控将这些因素分为两大类,并分析了单个因素对可听噪声预测值的影响程度,针对输电电路导线参数、杆塔型式和附加材料三个方面的内容,提出了几类切实可行的输电线路可听噪声减缓措施,为后续1000 kV交流输电线路的设计和建设提供参考。

  20. Voith power transmission systems in diesel multiple units and railcars. A review on recent developments

    Energy Technology Data Exchange (ETDEWEB)

    Paetzold, W. [Voith Turbo GmbH und Co. KG, Heidenheim (Germany). Rail Div.

    1999-04-01

    Voith today offers complete transmission systems consisting of hydrodynamic and hydromechanical transmissions with integrated retarders, cardan shafts, final drives and cooling units. For DMUs with underfloor powerpacks, the hydrodynamic power transmission system currently is the pre-eminent drive system worldwide and meets the established standards for rail service, i.e. high availability, low operating costs and a reasonable purchasing price. In this article, the author describes Voith`s contribution to the further development of these transmission systems in several modern dieselhydraulic railcars and DMUs for regional and main-line operations. (orig.)

  1. Harmonic analysis of AC/DC systems based on phase-domain multi-port network approach

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, O.; Fuerte-Esquivel, C.R. [Universidad Michoacana de San Nicolas de Hidalgo, Facultad de Ingenieria Electrica, Division de Estudios de Posgrado, Cuidad Universitaria, 58030 Morelia, Michoacan (Mexico); Rubio, J.A.; Guardado, J.L. [Instituto Tecnologico de Morelia, Av. Tecnologico 1500, 58120 Morelia, Michoacan (Mexico)

    2008-10-15

    This paper describes a phase-domain frequency domain technique to the harmonic analysis of a three-phase AC/DC system. The methodology is based on the harmonic multi-port network concept, expressed in terms of an ABCD parameter matrix which links voltage and current harmonics of different orders on both sides of the converter. Since the commutation angles are unknown, the harmonic interactions are computed by a sequential solution of the AC/DC system state variables, related by the ABCD matrix, and the updating of the commutation periods. A set of analytical equations has been derived to compute commutation times taking place in the converter. Test results are presented which demonstrate the effectiveness of the proposed methodology to assess harmonic interactions on both balanced and unbalanced operating conditions. The results are validated to those obtained by a time domain simulation. (author)

  2. Stress transmission through a model system of cohesionless elastic grains

    Science.gov (United States)

    Da Silva, Miguel; Rajchenbach, Jean

    2000-08-01

    Understanding the mechanical properties of granular materials is important for applications in civil and chemical engineering, geophysical sciences and the food industry, as well as for the control or prevention of avalanches and landslides. Unlike continuous media, granular materials lack cohesion, and cannot resist tensile stresses. Current descriptions of the mechanical properties of collections of cohesionless grains have relied either on elasto-plastic models classically used in civil engineering, or on a recent model involving hyperbolic equations. The former models suggest that collections of elastic grains submitted to a compressive load will behave elastically. Here we present the results of an experiment on a two-dimensional model system-made of discrete square cells submitted to a point load-in which the region in which the stress is confined is photoelastically visualized as a parabola. These results, which can be interpreted within a statistical framework, demonstrate that the collective response of the pile contradicts the standard elastic predictions and supports a diffusive description of stress transmission. We expect that these findings will be applicable to problems in soil mechanics, such as the behaviour of cohesionless soils or sand piles.

  3. Polar On-Line Acquisition Relay and Transmission System (POLARATS)

    Energy Technology Data Exchange (ETDEWEB)

    Yuracko, K.

    2004-07-15

    POLARATS (Polar On-Line Acquisition Relay And Transmission System) is being developed by YAHSGS LLC (YAHSGS) and Oak Ridge National Laboratory (ORNL) to provide remote, unattended monitoring of environmental parameters under harsh environmental conditions. In particular, instrumental design and engineering is oriented towards protection of human health in the Arctic, and with the additional goal of advancing Arctic education and research. POLARATS will obtain and transmit environmental data from hardened monitoring devices deployed in locations important to understanding atmospheric and aquatic pollutant migration as it is biomagnified in Arctic food chains. An Internet- and personal computer (PC)-based educational module will provide real time sensor data, on-line educational content, and will be integrated with workbooks and textbooks for use in middle and high school science programs. The educational elements of POLARATS include an Internet-based educational module that will instruct students in the use of the data and how those data fit into changing Arctic environments and food chains. POLARATS will: (1) Enable students, members of the community, and scientific researchers to monitor local environmental conditions in real time over the Internet; and (2) Provide additional educational benefits through integration with middle- and high-school science curricula. Information will be relayed from POLARATS devices to classrooms and libraries along with custom-designed POLARATS teaching materials that will be integrated into existing curricula to enhance the educational benefits realized from the information obtained.

  4. Smart Grid Wide-Area Transmission System Visualization

    Directory of Open Access Journals (Sweden)

    Thomas J. Overbye

    2015-12-01

    Full Text Available The installation of vast quantities of additional new sensing and communication equipment, in conjunction with building the computing infrastructure to store and manage data gathered by this equipment, has been the first step in the creation of what is generically referred to as the “smart grid” for the electric transmission system. With this enormous capital investment in equipment having been made, attention is now focused on developing methods to analyze and visualize this large data set. The most direct use of this large set of new data will be in data visualization. This paper presents a survey of some visualization techniques that have been deployed by the electric power industry for visualizing data over the past several years. These techniques include pie charts, animation, contouring, time-varying graphs, geographic-based displays, image blending, and data aggregation techniques. The paper then emphasizes a newer concept of using word-sized graphics called sparklines as an extremely effective method of showing large amounts of time-varying data.

  5. Analysis of DC Power Transmission Using High Tc Superconducting Cables

    Institute of Scientific and Technical Information of China (English)

    Jun-Lian Zhang; Jian-Xun Jin

    2008-01-01

    A conceptual superconducting DC cable model is designed and its magnetic fields distribution is analyzed with Ansoft/Maxwell soft. A DC Power transmission system is also studied by using the Matlab/Simulink. With the DC Line and AC Ground Fault, the system losses analysis is introduced.The analysis results mainly include the magnetic fields distribution of the HTS cable model with Ansoft/Maxwell, the system loss, the DC Line and AC Ground Fault with Matlab/Simulation.

  6. Damping effects of Supplementary Control Signals for Enhancement of Transient Stability in AC-DC Power Systems

    Directory of Open Access Journals (Sweden)

    Uma Vani M

    2010-07-01

    Full Text Available This paper discusses the impact of HVDC on Power System Stability and proposes a novel controlmechanism to augment the system angle stability. The effectiveness of the proposed controller is demonstrated by asingle machine-infinite bus system example. The performance of this controller, in comparison to the conventionalP and P-I controllers, is found to be very effective as a supplementary PID controller in damping generator rotoroscillations. The supplementary controls using signals derived from the AC systems to modulate the DC quantitiesis presented in this paper.

  7. 47 CFR 73.6024 - Transmission standards and system requirements.

    Science.gov (United States)

    2010-10-01

    ... RADIO SERVICES RADIO BROADCAST SERVICES Class A Television Broadcast Stations § 73.6024 Transmission... cause any condition of uncorrectable interference due to radiation of radio frequency energy outside...

  8. Study for wireless power transmission of nuclear robot system

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jongseog [Central Research Institute of Korea Hydro and Nuclear Power Co., Daejeon (Korea, Republic of)

    2013-05-15

    Gasoline engine or electric motor is generally used for driving power of working. Gasoline tank is uncomfortable to carry. Battery capacity does not sustain long time working. Frequent moving back of robot to power charger or refueling tank is inconvenient. Long power cable connection occur winding problem if there are complex structures in walking way. We need some solution for continuous supply of robot energy at the free moving condition of robot. 'Wireless power transmission' is one of the solutions. Some experiment result to transmit wireless power to moving robot is described herein. To find possible wireless power transmission method for nuclear robot, wireless power transmission tests were performed. As result of these tests, it was confirmed that wireless power transmission by using dipole and mat type magnetic induction were possible. As result of flying robot experiment, it was realized that development of light weight core for receiver and wave reflection device for high directional transmitter are necessary for practical use of the dipole type wireless power transmission. Small size core and high directional transmitter will be next target. Mat type wireless power transmission is regarded as useful for robot power charging station in the inside containment.

  9. Settlement Between Electric Transmission Companies under the Point of Connection Tariff or "Postal Stamp" System (Japanese)

    OpenAIRE

    Hatta, Tatsuo

    2009-01-01

    This paper discusses how an electric transmission company in a pass-through area should settle the cost of a pass-through with the neighboring transmission companies under the point-of-connection tariff system. First, the paper shows that if the cost of the pass-through is settled based on the principle that determines the (metered) power transmission fares for ordinary customers (i.e. injectors and withdrawers) of the transmission companies, the fare receipts of the pass-through transmission...

  10. Wavelet Based Fault Detection, Classification in Transmission System with TCSC Controllers

    Directory of Open Access Journals (Sweden)

    G.Satyanarayana,

    2015-08-01

    Full Text Available This paper presents simulation results of the application of distance relays for the protection of transmission systems employing flexible alternating current transmission controllers such as Thyristor Controlled Series Capacitor (TCSC. The complete digital simulation of TCSC within a transmission system is performed in the MATLAB/Simulink environment using the Power System Block set (PSB. This paper presents an efficient method based on wavelet transforms both fault detection and classification which is almost independent of fault impedance, fault location and fault inception angle of transmission line fault currents with FACTS controllers.

  11. Simulation Study on Coil Design of Wireless Power Transfer System for Optimal Transmission Efficiency

    Directory of Open Access Journals (Sweden)

    Hao Qiang

    2013-05-01

    Full Text Available As an emerging research field, Wireless Power Transfer (WPT has attracted wide spread attention recently. In this study, the coil design of WPT system for optimal transmission efficiency is investigated. We deduce Tthe design criteria are deduced to meet various conditions of transmission distance and load. The results of simulation and experiment show the transmission efficiency from transmitting coil to receiving coil can keep high when the corresponding optimal condition is achieved. Thusen it can improve the overall transmission efficiency of the WPT system and it makes it suitable for the practical application of WPT system.

  12. Development of the automatic measurement system for ac losses in superconductors; Jido koryu sonshitsu sokutei sochi no kaihatsu (4)

    Energy Technology Data Exchange (ETDEWEB)

    Tsumura, K.; Kajikawa, K.; Iwakuma, M.; Funaki, K. [Kyushu University, Fukuoka (Japan)

    1999-11-10

    The rapid extension of the application field of the superconductive technology is expected by the discovery of the oxide superconductor. Though research and development for the sake is carried out in many research institute, it is quick in order to attempt the efficiency improvement of that research, and it is necessary to develop the equipment which can be evaluated simply and high-precise in respect of characteristics of the superconductive conductor. In this study, by putting the marketing in the future in visual field, it aims even in the characteristic inside of the superconductive conductor at the development of automatic alternating current measuring device of the important ac loss. And, it is possible that this equipment also carries out not only wire rod but also loss measurement of coil winding. Ac loss measurement of superconductive pulse coil of refrigerating machine direct cooling system was carried out using this measuring device this time. (NEDO)

  13. An ultra low-noise AC beam transformer and digital signal processing system for CERN's ELENA ring

    CERN Document Server

    Angoletta, M E; Caspers, F; Federmann, S; Molendijk, J; Pedersen, F; Sanchez-Quesada, J

    2013-01-01

    CERN’s Extra Low ENergy Antiproton (ELENA) ring is a new synchrotron that will be commissioned in 2016 to further decelerate the antiprotons coming from CERN’s Antiproton Decelerator (AD). Essential longitudinal diagnostics required for commissioning and operation include the intensity measurement for bunched and debunched beams and the measurement of p/p for debunched beams to assess the electron cooling performance. The beam phase information is also needed by the Low-Level RF (LLRF) system. The baseline system for providing the required beam parameters and signals is based upon two ultra-low-noise AC beam transformers and associated digital signal processing. The AC beam transformers cover different frequency regions and are an adaptation to the ELENA layout of those used in the AD. Two AC beam transformers will also be installed in the extraction lines to provide beam intensity measurements. The digital signal processing will be carried out with the leadingedge hardware family used for ELENA’s L...

  14. HVDC: A key solution in future transmission systems

    Energy Technology Data Exchange (ETDEWEB)

    Heyman, Olof H.; Weimers, Lars; Bohl, Mie-Lotte

    2010-09-15

    With the transition of power grids, based on sustainable generation, HVDC is a key technology with new applications. This includes connection of remote wind parks and strengthening of existing AC grids. In addition, traditional applications, such as bulk hydropower transfer and interconnections between regions, play a major role in our transition to sustainable generation and the associated grids. The technology for regional grids with a limited number of nodes is already in place and commercial projects are commissioned. For extensive grids, development and verification are ongoing in parallel to industry standards being discussed in groups such as ENTSO-E and CIGRE.

  15. 47 CFR 74.795 - Digital low power TV and TV translator transmission system facilities.

    Science.gov (United States)

    2010-10-01

    ... translator transmission system facilities. (a) A digital low power TV or TV translator station shall operate... 47 Telecommunication 4 2010-10-01 2010-10-01 false Digital low power TV and TV translator transmission system facilities. 74.795 Section 74.795 Telecommunication FEDERAL COMMUNICATIONS...

  16. Experimental characterization of dispersion maps with Raman gain in 160 Gb/s transmission systems

    DEFF Research Database (Denmark)

    Zhenbo, Xu; Seoane, Jorge; Siahlo, Andrei;

    2004-01-01

    We investigate the combined effects of dispersion compensation and Raman amplification in SMF-based transmission span of 160 Gb/s system. The post compensation map shows better power tolerance.......We investigate the combined effects of dispersion compensation and Raman amplification in SMF-based transmission span of 160 Gb/s system. The post compensation map shows better power tolerance....

  17. AC800M系列控制器在水电站计算机监控系统中的应用%AC800M Series Controller in Hydropower Station Computer Monitoring System

    Institute of Scientific and Technical Information of China (English)

    杨永琼; 汤敏; 方大富; 严茂强; 卢兴

    2012-01-01

    The programming and debugging environment,object linking and embedding for process control(OPC),system reliability design,system communication network,and other technical characteristics of AC800M series controller are introduced.Combining with the implementation of engineering computer monitoring for Sichuan Jialing river Shaxi avionics systems,the application of AC800M series controller in domestic hydropower station computer monitoring system is mainly expounded.%介绍了AC800M系列控制器的编程与调试环境、用于过程控制的对象连接与嵌入(OPC)技术、系统可靠性设计、系统通信网络等方面的特点。结合嘉陵江沙溪航电工程中水电站计算机监控系统的实施案例,主要阐述了AC800M系列控制器在国内水电站计算机监控系统中的具体应用。

  18. Performance analysis for optimum transmission and comparison with maximal ratio transmission for MIMO systems with cochannel interference

    Directory of Open Access Journals (Sweden)

    Lin Sheng-Chou

    2011-01-01

    Full Text Available Abstract This article presents the performance analysis of multiple-input/multiple-output (MIMO systems with quadrature amplitude modulation (QAM transmission in the presence of cochannel interference (CCI in nonfading and flat Rayleigh fading environments. The use of optimum transmission (OT and maximum ratio transmission (MRT is considered and compared. In addition to determining precise results for the performance of QAM in the presence of CCI, it is our another aim in this article to examine the validity of the Gaussian interference model in the MRT-based systems. Nyquist pulse shaping and the effects of cross-channel intersymbol interference produced by CCI due to random symbol of the interfering signals are considered in the precise interference model. The error probability for each fading channel is estimated fast and accurately using Gauss quadrature rules which can approximate the probability density function (pdf of the output residual interference. The results of this article indicate that Gaussian interference model may overestimate the effects of interference, particularly, for high-order MRT-based MIMO systems over fading channels. In addition, OT cannot always outperform MRT due to the significant noise enhancement when OT intends to cancel CCI, depending on the combination of the antennas at the transmitter and the receiver, number of interference and the statistical characteristics of the channel.

  19. Preliminary survey of integrated monitoring system for transmission liens. Sodensen sogo kanshi system no yobi kento

    Energy Technology Data Exchange (ETDEWEB)

    Sasano, Takao; Nishiyama, Fumihiko

    1988-04-01

    The integrated monitoring system of transmission lines utilizing ground wire with built-in optical fibres(OPGW) which was put to practical use was surveyed. The overhead transmission lines have potential to be impeded supply owing to the line exposure to severe natural envioronment or by the change of surrounding environment such as trees, buildings under lines and ground or by deterioration of equipments. This report describes the system to monitor integrally the transmission lines by using OPGW or sensor technology to maintain and operate with higher reliability and lower cost and to reflect in the design, except the conventional maintenance and checking. The effect to foresee and prevent accidents is expected from this system, but the regional difference must be considered. This system can provide continously reliable monitoring, collection of maintenance informations and operation support and further can provide accident informations to be used in the design through the evaluation. It is necessary to use highly reliable repeaters for optical informations, protect instruments under intense field, prevent malfunction and develop the auto-movable robot for taking picture and local weather prediction system in order to realize this system. (5 figs, 6 tabs, 8 refs)

  20. Design and Realization of Phased Array Radar Optical Fiber Transmission System

    Institute of Scientific and Technical Information of China (English)

    HU Shan-qing; LIU Feng; LONG Teng

    2007-01-01

    One optical fiber transmission system is designed.The modularization optical fiber transmission adapters were utilized in the system,so the system structure could be flexibly scalable.The sub-array adapter and signal processor adapter were designed and realized utilizing the new field programmable gate array (FPGA) which could drive the optical transceiver.The transmission agreement was designed based on the data stream.In order to solve the signal synchronization problem of the optical fiber transmitted phased array radar,a method named synchronous clock was designed.The fiber transmission error code rate of the system was zero with an experimental transmission velocity of 800 Mbit/s.The phased array radar system has detected the airplane target,thus validated the feasibility of the design method.

  1. Parameter design and performance analysis of zero inertia continuously variable transmission system

    Institute of Scientific and Technical Information of China (English)

    胡建军; 吉毅; 晏玖江

    2015-01-01

    In order to solve the problem of weak power performance of vehicle equipped with continuously variable transmission (CVT) system working under transient operating conditions, a new CVT equipped with planetary gear mechanism and flywheel was researched, a design method of transmission parameter optimization was proposed, and the comprehensive matching control strategy was established for the new transmission system. Fuzzy controllers for throttle opening and CVT speed ratio were designed, and power performance and fuel economy of both vehicles respectively equipped with conventional CVT system and new transmission system wrere compared and analyzed by simulation. The results show that power performance and fuel economy of the vehicle equipped with new transmission system are better than that equipped with conventional CVT, thus the rationality of the parameter design method and control algorithm are verified.

  2. PROXY-BASED PATCHING STREAM TRANSMISSION STRATEGY IN MOBILE STREAMING MEDIA SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Liao Jianxin; Lei Zhengxiong; Ma Xutao; Zhu Xiaomin

    2006-01-01

    A mobile transmission strategy, PMPatching (Proxy-based Mobile Patching) transmission strategy is proposed, it applies to the proxy-based mobile streaming media system in Wideband Code Division Multiple Access (WCDMA) network. Performance of the whole system can be improved by using patching stream to transmit anterior part of the suffix that had been played back, and by batching all the demands for the suffix arrived in prefix period and patching stream transmission threshold period. Experimental results show that this strategy can efficiently reduce average network transmission cost and number of channels consumed in central streaming media server.

  3. Virtual Pipeline System Testbed to Optimize the U.S. Natural Gas Transmission Pipeline System

    Energy Technology Data Exchange (ETDEWEB)

    Kirby S. Chapman; Prakash Krishniswami; Virg Wallentine; Mohammed Abbaspour; Revathi Ranganathan; Ravi Addanki; Jeet Sengupta; Liubo Chen

    2005-06-01

    The goal of this project is to develop a Virtual Pipeline System Testbed (VPST) for natural gas transmission. This study uses a fully implicit finite difference method to analyze transient, nonisothermal compressible gas flow through a gas pipeline system. The inertia term of the momentum equation is included in the analysis. The testbed simulate compressor stations, the pipe that connects these compressor stations, the supply sources, and the end-user demand markets. The compressor station is described by identifying the make, model, and number of engines, gas turbines, and compressors. System operators and engineers can analyze the impact of system changes on the dynamic deliverability of gas and on the environment.

  4. Error Assessment of Solar Irradiance Forecasts and AC Power from Energy Conversion Model in Grid-Connected Photovoltaic Systems

    Directory of Open Access Journals (Sweden)

    Gianfranco Chicco

    2015-12-01

    Full Text Available Availability of effective estimation of the power profiles of photovoltaic systems is essential for studying how to increase the share of intermittent renewable sources in the electricity mix of many countries. For this purpose, weather forecasts, together with historical data of the meteorological quantities, provide fundamental information. The weak point of the forecasts depends on variable sky conditions, when the clouds successively cover and uncover the solar disc. This causes remarkable positive and negative variations in the irradiance pattern measured at the photovoltaic (PV site location. This paper starts from 1 to 3 days-ahead solar irradiance forecasts available during one year, with a few points for each day. These forecasts are interpolated to obtain more irradiance estimations per day. The estimated irradiance data are used to classify the sky conditions into clear, variable or cloudy. The results are compared with the outcomes of the same classification carried out with the irradiance measured in meteorological stations at two real PV sites. The occurrence of irradiance spikes in “broken cloud” conditions is identified and discussed. From the measured irradiance, the Alternating Current (AC power injected into the grid at two PV sites is estimated by using a PV energy conversion model. The AC power errors resulting from the PV model with respect to on-site AC power measurements are shown and discussed.

  5. Non-systemic transmission of tick-borne diseases: A network approach

    Science.gov (United States)

    Ferreri, Luca; Bajardi, Paolo; Giacobini, Mario

    2016-10-01

    Tick-borne diseases can be transmitted via non-systemic (NS) transmission. This occurs when tick gets the infection by co-feeding with infected ticks on the same host resulting in a direct pathogen transmission between the vectors, without infecting the host. This transmission is peculiar, as it does not require any systemic infection of the host. The NS transmission is the main efficient transmission for the persistence of the tick-borne encephalitis virus in nature. By describing the heterogeneous ticks aggregation on hosts through a bipartite graphs representation, we are able to mathematically define the NS transmission and to depict the epidemiological conditions for the pathogen persistence. Despite the fact that the underlying network is largely fragmented, analytical and computational results show that the larger is the variability of the aggregation, and the easier is for the pathogen to persist in the population.

  6. Condition Assessment Technologies for Water Transmission and Distribution Systems

    Science.gov (United States)

    As part of the U.S. Environmental Protection Agency’s (EPA’s) Aging Water Infrastructure Research Program, this research was conducted to identify and characterize the state of the technology for structural condition assessment of drinking water transmission and distribution syst...

  7. Condition Assessment of Drinking Water Transmission and Distribution Systems

    Science.gov (United States)

    Condition assessment of water transmission and distribution mains is the collection of data and information through direct and/or indirect methods, followed by analysis of the data and information, to make a determination of the current and/or future structural, water quality, an...

  8. 47 CFR 73.875 - Modification of transmission systems.

    Science.gov (United States)

    2010-10-01

    ... RADIO BROADCAST SERVICES Low Power FM Broadcast Stations (LPFM) § 73.875 Modification of transmission... application on FCC Form 318. (1) Any construction of a new tower structure for broadcast purposes, except for replacement of an existing tower with a new tower of identical height and geographic coordinates. (2)...

  9. Initial assessment: electromagnetic compatibility aspects of proposed SPS Microwave Power Transmission System (MPTS) operations

    Energy Technology Data Exchange (ETDEWEB)

    1978-02-01

    An analysis of major concerns with regard to the effects on radio and electronic systems by the proposed Microwave Power Transmission System for transmitting power from a satellite solar power station to earth is presented. (LCL)

  10. Analysis of transmission efficiency of the superconducting resonance coil according the materials of cooling system

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yu Kyeong; Hwang, Jun Won; Choi, Hyo Sang [Chosun University, Gwangju (Korea, Republic of)

    2016-03-15

    The wireless power transfer (WPT) system using a magnetic resonance was based on magnetic resonance coupling of the transmission and the receiver coils. In these system, it is important to maintain a high quality-factor (Q-factor) to increase the transmission efficiency of WPT system. Our research team used a superconducting coil to increase the Q-factor of the magnetic resonance coil in WPT system. When the superconductor is applied in these system, we confirmed that transmission efficiency of WPT system was higher than normal conductor coil through a preceding study. The efficiency of the transmission and the receiver coil is affected by the magnetic shielding effect of materials around the coils. The magnetic shielding effect is dependent on the type, thickness, frequency, distance, shape of materials. Therefore, it is necessary to study the WPT system on the basis of these conditions. In this paper, the magnetic shield properties of the cooling system were analyzed using the High-Frequency Structure Simulation (HFSS, Ansys) program. We have used the shielding materials such as plastic, aluminum and iron, etc. As a result, when we applied the fiber reinforced polymer (FRP), the transmission efficiency of WPT was not affected because electromagnetic waves went through the FRP. On the other hand, in case of a iron and aluminum, transmission efficiency was decreased because of their electromagnetic shielding effect. Based on these results, the research to improve the transmission efficiency and reliability of WPT system is continuously necessary.

  11. Seismic Performance Research of Transmission Tower in Consideration of the Pile-soil-structure System

    Science.gov (United States)

    Liu, Chuncheng; Mao, Long; Wang, Chongyang; Zha, Chuanming

    2016-11-01

    The seismic performance of transmission tower in consideration of pile-soil- structure dynamic interaction is researched through numerical simulation. Based on a transmission tower of a specific project, pile-soil-transmission tower coupled system is established. By using the method of time history, the pile-soil- transmission tower system dynamic response under seismic load were calculated, and comparing with the results without considering interaction system. Results show that, after considering interaction of the system, the period of the structure have extended and the mode of the structure lagged. On soft sites, compare with no considering the interaction, the results have a big difference, the relative increment of the maximum displacement at the top of the tower is 39.82%, respectively. Therefore it is suggested that the pile-soil-structure dynamic interaction should be fully considered in aseismic design of transmission tower on soft sites and medium soft sites.

  12. A Sandbox Development For Demonstrating Bom Transmission In A Plm And Erp Integrated System

    OpenAIRE

    Zeng, Zhen

    2014-01-01

    Integrating Product Lifecycle Management (PLM) and Enterprise Resource Planning (ERP) in a company is important. Currently, many companies have difficulties on integrating PLM and ERP systems. This study developed a prototype (sandbox) of PLM and ERP integrated system for demonstrating BOM transmission in a PLM and ERP integrated system, describing key aspects of system integration and BOM transmission. This sandbox will facilitate users' knowledge on how to process transactions in a PLM and ...

  13. Design and Implementation of New Electromagnetic Coupling DC/AC Power Transmission Circuit%新型电磁耦合DC/AC电能传输电路的设计与实现

    Institute of Scientific and Technical Information of China (English)

    何伊妮; 杭乃善; 方柳; 曾智翔

    2012-01-01

    从电磁感应原理出发,仿照同步机电磁耦合机理,提出一种静止的电磁型DC/AC电能传输方式.同时给出该原理的数学推导和新型逆变电路的工作原理.通过对电路模型进行仿真分析,验证了理论的正确性和可行性.最后总结预测了该原理作为一种新型逆变技术的应用前景.对换流输电领域开展研究具有一定的参考价值.%Starting from the principle of electromagnetic inductive and by use of the synchronous generator electromagnetic coupling mechanism, this paper proposes the way of static electromagnetic DC/AC power transmission, presenting the mathematic derivation of the principle and the working principle of the new inverter circuit. Through the simulation analysis of the electric circuit model,the theory is proved accurate and feasible. Finally, the application prospect of the new DC/AC electromagnetic equipment is discussed. The discussion in the paper has a certain reference value in the conversion technology research.

  14. Performance Evaluation on Transmission Tower-Line System with Passive Friction Dampers Subjected to Wind Excitations

    Directory of Open Access Journals (Sweden)

    Bo Chen

    2015-01-01

    Full Text Available The vibration control and performance evaluation on a transmission-tower line system by using friction dampers subjected to wind excitations are carried out in this study. The three-dimensional finite element (FE model of a transmission tower is firstly constructed. A two-dimensional lumped mass model of a transmission tower is developed for dynamic analysis. The analytical model of transmission tower-line system is proposed by taking the dynamic interaction between the tower and the transmission lines into consideration. The mechanical model of passive friction damper is presented by involving the effects of damper axial stiffness. The equation of motion of the transmission tower-line system incorporated with the friction dampers disturbed by wind excitations is established. A real transmission tower-line system is taken as an example to examine the feasibility and reliability of the proposed control approach. An extensive parameter study is carried out to find the optimal parameters of friction damper and to assess the effects of slipping force axial stiffness and hysteresis loop on control performance. The work on an example structure indicates that the application of friction dampers with optimal parameters could significantly reduce wind-induced responses of the transmission tower-line system.

  15. Transmission needs across a fully renewable European power system

    CERN Document Server

    Rodriguez, Rolando A; Andresen, Gorm B; Heide, Dominik; Greiner, Martin

    2013-01-01

    The residual load and excess power generation of 27 European countries with a 100% penetration of variable renewable energy sources are explored in order to quantify the benefit of power transmission between countries. Estimates are based on extensive weather data, which allows for modelling of hourly mismatches between the demand and renewable generation from wind and solar photovoltaics. For separated countries, balancing is required to cover around 24% of the total annual energy consumption. This number can be reduced down to 15% once all countries are networked together with uncon- strained interconnectors. The reduction represents the maximum possible benefit of transmission for the countries. The total Net Transfer Capacity of the unconstrained interconnectors is roughly twelve times larger than current values. However, constrained interconnector capacities six times larger than the current values are found to provide 97% of the maximum possible benefit of cooperation. This motivates a detailed investig...

  16. Optical signal monitoring in phase modulated optical fiber transmission systems

    Science.gov (United States)

    Zhao, Jian

    Optical performance monitoring (OPM) is one of the essential functions for future high speed optical networks. Among the parameters to be monitored, chromatic dispersion (CD) is especially important since it has a significant impact on overall system performance. In this thesis effective CD monitoring approaches for phase-shift keying (PSK) based optical transmission systems are investigated. A number of monitoring schemes based on radio frequency (RF) spectrum analysis and delay-tap sampling are proposed and their performance evaluated. A method for dispersion monitoring of differential phase-shift keying (DPSK) signals based on RF power detection is studied. The RF power spectrum is found to increase with the increase of CD and decrease with polarization mode dispersion (PMD). The spectral power density dependence on CD is studied theoretically and then verified through simulations and experiments. The monitoring sensitivity for nonreturn-to-zero differential phase-shift keying (NRZ-DPSK) and return-to-zero differential phase-shift keying (RZ-DPSK) based systems can reach 80ps/nm/dB and 34ps/nm/dB respectively. The scheme enables the monitoring of differential group delay (DGD) and CD simultaneously. The monitoring sensitivity of CD and DGD can reach 56.7ps/nm/dB and 3.1ps/dB using a bandpass filter. The effects of optical signal-to-noise ratio (OSNR), DGD, fiber nonlinearity and chirp on the monitoring results are investigated. Two RF pilot tones are employed for CD monitoring of DPSK signals. Specially selected pilot tone frequencies enable good monitoring sensitivity with minimum influence on the received signals. The dynamic range exceeding 35dB and monitoring sensitivity up to 9.5ps/nm/dB are achieved. Asynchronous sampling technique is employed for CD monitoring. A signed CD monitoring method for 10Gb/s NRZ-DPSK and RZ-DPSK systems using asynchronous delay-tap sampling technique is studied. The demodulated signals suffer asymmetric waveform distortion if

  17. HIV transmission in a state prison system, 1988-2005.

    Directory of Open Access Journals (Sweden)

    Krishna Jafa

    Full Text Available INTRODUCTION: HIV prevalence among state prison inmates in the United States is more than five times higher than among nonincarcerated persons, but HIV transmission within U.S. prisons is sparsely documented. We investigated 88 HIV seroconversions reported from 1988-2005 among male Georgia prison inmates. METHODS: We analyzed medical and administrative data to describe seroconverters' HIV testing histories and performed a case-crossover analysis of their risks before and after HIV diagnosis. We sequenced the gag, env, and pol genes of seroconverters' HIV strains to identify genetically-related HIV transmission clusters and antiretroviral resistance. We combined risk, genetic, and administrative data to describe prison HIV transmission networks. RESULTS: Forty-one (47% seroconverters were diagnosed with HIV from July 2003-June 2005 when voluntary annual testing was offered. Seroconverters were less likely to report sex (OR [odds ratio] = 0.02, 95% CI [confidence interval]: 0-0.10 and tattooing (OR = 0.03, 95% CI: <0.01-0.20 in prison after their HIV diagnosis than before. Of 67 seroconverters' specimens tested, 33 (49% fell into one of 10 genetically-related clusters; of these, 25 (76% reported sex in prison before their HIV diagnosis. The HIV strains of 8 (61% of 13 antiretroviral-naïve and 21 (40% of 52 antiretroviral-treated seroconverters were antiretroviral-resistant. DISCUSSION: Half of all HIV seroconversions were identified when routine voluntary testing was offered, and seroconverters reduced their risks following their diagnosis. Most genetically-related seroconverters reported sex in prison, suggesting HIV transmission through sexual networks. Resistance testing before initiating antiretroviral therapy is important for newly-diagnosed inmates.

  18. Linearization Technologies for Broadband Radio-Over-Fiber Transmission Systems

    Directory of Open Access Journals (Sweden)

    Xiupu Zhang

    2014-11-01

    Full Text Available Linearization technologies that can be used for linearizing RoF transmission are reviewed. Three main linearization methods, i.e. electrical analog linearization, optical linearization, and electrical digital linearization are presented and compared. Analog linearization can be achieved using analog predistortion circuits, and can be used for suppression of odd order nonlinear distortion components, such as third and fifth order. Optical linearization includes mixed-polarization, dual-wavelength, optical channelization and the others, implemented in optical domain, to suppress both even and odd order nonlinear distortion components, such as second and third order. Digital predistortion has been a widely used linearization method for RF power amplifiers. However, digital linearization that requires analog to digital converter is severely limited to hundreds of MHz bandwidth. Instead, analog and optical linearization provide broadband linearization with up to tens of GHz. Therefore, for broadband radio over fiber transmission that can be used for future broadband cloud radio access networks, analog and optical linearization are more appropriate than digital linearization. Generally speaking, both analog and optical linearization are able to improve spur-free dynamic range greater than 10 dB over tens of GHz. In order for current digital linearization to be used for broadband radio over fiber transmission, the reduced linearization complexity and increased linearization bandwidth are required. Moreover, some digital linearization methods in which the complexity can be reduced, such as Hammerstein type, may be more promising and require further investigation.

  19. Dynamic Efficiency of a Container Crane’s Hoisting Transmission System under Hoisting Dynamic Load

    Directory of Open Access Journals (Sweden)

    Yuanyuan Liu

    2016-01-01

    Full Text Available The dynamic efficiency of hoisting transmission system on a container crane is fundamental for accurate efficiency prediction, while the dynamic efficiency of hoisting transmission system has not been investigated sufficiently. This paper will focus on dynamic efficiency of hoisting transmission system under hoisting dynamic load. A power loss model of gearbox was built. Then the dynamic model of gear transmission was developed including time-varying mesh stiffness and hoisting dynamic load was studied. Power loss, dynamic efficiency, and equivalent static efficiency were conducted in hoisting and lowering working conditions. The result shows that dynamic efficiency which consists of the significant lower frequency component coincided with hoisting load torque of the higher frequency component which is directly related to dynamic mesh and bearing force. And in two processes, the equivalent static efficiency in constant speed stage is min, whereas maximum value occurs in different stage. The research results lay a foundation for hoisting gear transmission dynamic efficiency analysis.

  20. Experimental Investigation on Surface Conditions of Conductors in AC Power Transmission Lines%交流输电线路导线表面状态的实验研究

    Institute of Scientific and Technical Information of China (English)

    卞星明; 杨文言; 赵磊; 王黎明; 关志成

    2011-01-01

    导线表面状态是影响其电晕特性的重要因素,研究实际运行后导线的表面状态对输电线路的设计、运行都有着重要的理论意义.为此,选取了华北、华中和华南典型地区的500 kV交流输电线路导线及新导线样本进行了表面状态的研究.场发射环境扫描电子显微镜的实验结果表明:实际运行后导线的表面物质成分比新导线大大增加,表面形貌更加凹凸不平;非金属元素主要含有碳、氧、硅、硫,金属元素主要含有铝、铁、钙、钾、钠、镁.表面形貌仪的实验结果表明:与新导线相比,运行后导线的粗糙度增加,同一地区的导线表面粗糙度相差不大,随着运行时间的增加,导线表面粗糙程度有所提高.%The influence of conductor surface conditions on corona discharge is of great value to the design and operation of power transmission lines in power system. Six strands of the aged conductors acquired from 500 kV AC transmission lines in northern, central, southern China respectively and two strands of the new conductors China were used. The results of scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDX) showed that the morphologies of the aged strands were greatly different from the new ones. The aged strands had been corrupted in the ambient atmospheric conditions during their long-term operating in power grid; many substances in the neighborhood of the conductors were also adhered to the surfaces as a result of the strong electric field and gravitational force. Therefore, the surfaces of the aged strands are much coarser and more uneven than the new ones. For the new strands, aluminum is the main component, there are few impurities. However, in the surface layer of the aged strands, there are many other elements, such as oxygen, carbon, silicon, sulfur, chlorine, kalium, calcium, zincum, natrium, iron, magnesium etc. Two basic roughness parameters Ra and Rq were introduced to express

  1. The integration of renewable energy sources into electric power transmission systems

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, P.R.; Dykas, W.P.; Kirby, B.J.; Purucker, S.L. [Oak Ridge National Lab., TN (United States); Lawler, J.S. [Univ. of Tennessee, Knoxville, TN (United States)

    1995-07-01

    Renewable energy technologies such as photovoltaics, solar thermal power plants, and wind turbines are nonconventional, environmentally attractive sources of energy that can be considered for electric power generation. Many of the areas with abundant renewable energy resources (very sunny or windy areas) are far removed from major load centers. Although electrical power can be transmitted over long distances of many hundreds of miles through high-voltage transmission lines, power transmission systems often operate near their limits with little excess capacity for new generation sources. This study assesses the available capacity of transmission systems in designated abundant renewable energy resource regions and identifies the requirements for high-capacity plant integration in selected cases. In general, about 50 MW of power from renewable sources can be integrated into existing transmission systems to supply local loads without transmission upgrades beyond the construction of a substation to connect to the grid. Except in the Southwest, significant investment to strengthen transmission systems will be required to support the development of high-capacity renewable sources of 1000 MW or greater in areas remote from major load centers. Cost estimates for new transmission facilities to integrate and dispatch some of these high-capacity renewable sources ranged from several million dollars to approximately one billion dollars, with the latter figure an increase in total investment of 35%, assuming that the renewable source is the only user of the transmission facility.

  2. Communication protocol in chassis detecting wireless transmission system based on WiFi

    Science.gov (United States)

    In chassis detecting wireless transmission system, the wireless network communication protocol plays a key role in the information exchange and synchronization between the host and chassis PDA. This paper presents a wireless network transmission protocol based on TCP/IP which makes the rules of info...

  3. Joint impact of quantization and clipping on single- and multi-carrier block transmission systems

    NARCIS (Netherlands)

    Yang, H.; Schenk, T.C.W.; Smulders, P.F.M.; Fledderus, E.R.

    2008-01-01

    This work investigates the joint impact of quantization and clipping, caused by analog-to-digital converters (ADCs) with low bit resolutions, on single- and multi-carrier block transmission systems in wireless multipath environments. We consider single carrier block transmission with frequency domai

  4. Speed Control of DC Motor using AC/AC/DC Converter Based on Intelligent Techniques

    Directory of Open Access Journals (Sweden)

    Rakan Kh Antar

    2013-05-01

    Full Text Available    This paper describes the application of ac/ac/dc and ac/dc converters to control the speed of a separately excited DC motor. Artificial neural network and PI controller are trained to select the desired values of firing angles for triggering thyristors of the ac/ac/dc and ac/dc bridge converters in order to control the speed of the dc motor at a desired value with constant and different load torques in order to obtain the best speed response. Simulation results show that the rising time for ac/dc and ac/ac/dc converters at 250rpm are reduced about 79% and 89% respectively, while delay time it reduced about 69% and 64% respectively. Therefore, speed response of the dc motor is more efficient for closed loop system compared with open loop also the response of ac/ac/dc converter is better than ac/dc converter.

  5. Facts controllers in power transmission and distribution

    CERN Document Server

    Padiyar, KR

    2007-01-01

    About the Book: The emerging technology of Flexible AC Transmission System (FACTS) enables planning and operation of power systems at minimum costs, without compromising security. This is based on modern high power electronic systems that provide fast controllability to ensure ''flexible'' operation under changing system conditions. This book presents a comprehensive treatment of the subject by discussing the operating principles, mathematical models, control design and issues that affect the applications. The concepts are explained often with illustrative examples and case studies. In partic

  6. AC/DC Power Conversion System Using 3/9 Multiphase Transformer

    Directory of Open Access Journals (Sweden)

    Ahmad Hoteit

    2012-07-01

    Full Text Available The main idea of this paper is to build a 3/9 AC multiphase transformer for conversion into DC power through the rectifier circuit which contains 18 pulse rectification with a ripple factor less than 0.8% produced by the odd phase number 9. This modeling has been simulated using Orcad simulation software, the nine phases are out of the main three phase power lines, each phase is shifted from the other by 40o (360o/9, this type of transformer is often required in aerospace, railway and automobile applications.

  7. Noise and signal interference in optical fiber transmission systems an optimum design approach

    CERN Document Server

    Bottacchi, Stefano

    2008-01-01

    A comprehensive reference to noise and signal interference in optical fiber communications Noise and Signal Interference in Optical Fiber Transmission Systems is a compendium on specific topics within optical fiber transmission and the optimization process of the system design. It offers comprehensive treatment of noise and intersymbol interference (ISI) components affecting optical fiber communications systems, containing coverage on noise from the light source, the fiber and the receiver. The ISI is modeled with a statistical approach, leading to new useful computational m

  8. Wideband Analog Transmission System Based on the External Intensity Electro-Optic Modulator

    Directory of Open Access Journals (Sweden)

    Jiri Svarny

    2016-01-01

    Full Text Available The work deals with design and integration of an analog electro-optic transmission system suitable for some specialized tasks of diagnostics and measurements. The system is based on principle of external intensity modulation of fiber guided laser radiation. Besides wideband and almost lossless transmission the system tolerates extreme length of the transmitting medium and ensures ultimate galvanic barrier between the input and output.

  9. Design of wireless video transmission system based on STM32 microcontroller

    Science.gov (United States)

    Yang, Fan; Ma, Chunting; Li, Haoyi

    2017-03-01

    The design of a wireless video transmission system based on STM32, the system uses the STM32F103VET6 microprocessor as the core, through the video acquisition module collects video data, video data will be sent to the receiver through the wireless transmitting module, receiving data will be displayed on the LCD screen. The software design process of receiver and transmitter is introduced. The experiment proves that the system realizes wireless video transmission function.

  10. 风火打捆交直流混联送端系统暂态稳定性分析%Analysis on Transient Stability for Wind-thermal-bundled Power Transmitted by AC/DC System

    Institute of Scientific and Technical Information of China (English)

    赵祥; 张师; 周毅博; 孟祥辉; 于昊; 王鹤萤

    2015-01-01

    风火打捆通过交直流混联外送电能已成为目前大规模风电基地比较常用的能源输送方式。在这种输送方式中,交直流混联、风电输送功率占总输送功率的比例和风电机组的类型等都会对风火打捆送端系统的暂态稳定性产生影响。在建立风电场模型、控制系统模型和混联输电系统模型的基础上,分析交直流混联对暂态稳定性的影响,研究不同风电机组类型对暂态稳定的影响,研究风电输出功率所占比例的改变对送端暂态稳定的影响。最后,通过分析得出:双馈感应发电机与常规火电机组打捆系统暂态稳定性好于另外两种类型风电机组;且双馈感应发电机在保证原动机出力稳定的情况下增加配比,有利于火电机组的功角稳定性。%Since wind power is explored on a large scale, it is a regular way for power transmission that the electricity generated from wind-thermal base is transmitted via AC/DC transmission system. The AC/DC transmission, the proportion of wind power to the total transmission power and the different kinds of wind turbine generators can influence the transient stability of the AC/DC transmission system with wind-thermal combined generation. First, the wind farm models, control system models and hybrid transmission models are founded. Then, the influences of AC/DC transmission system upon the transient stability are analyzed, and the influence of different kinds of wind turbine generators and the change of wind power proportion upon the transient stability is studied. At last, it is concluded through analysis that the transient stability of double fed induction generator (DFIG) and conventional wind generator bundled with thermal generation are better than the two other wind turbine generators, and while ensuring stable mechanical output, increasing proportion of DFIG will benefit the angle stability of thermal generators.

  11. Analytical method for coupled transmission error of helical gear system with machining errors, assembly errors and tooth modifications

    Science.gov (United States)

    Lin, Tengjiao; He, Zeyin

    2017-07-01

    We present a method for analyzing the transmission error of helical gear system with errors. First a finite element method is used for modeling gear transmission system with machining errors, assembly errors, modifications and the static transmission error is obtained. Then the bending-torsional-axial coupling dynamic model of the transmission system based on the lumped mass method is established and the dynamic transmission error of gear transmission system is calculated, which provides error excitation data for the analysis and control of vibration and noise of gear system.

  12. Modelling ac ripple currents in HTS coated conductors

    Science.gov (United States)

    Xu, Zhihan; Grilli, Francesco

    2015-10-01

    Dc transmission using high temperature superconducting (HTS) coated conductors (CCs) offers a promising solution to the globally growing demand for effective, reliable and economic transmission of green energy up to the gigawatt level over very long distances. The credible estimation of the losses and thereby the heat dissipation involved, where ac ripples (introduced in rectification/ac-dc conversion) are viewed as a potential source of notable contribution, is highly essential for the rational design of practical HTS dc transmission cables and corresponding cryogenic systems to fulfil this demand. Here we report a targeted modelling study into the ac losses in a HTS CC subject to dc and ac ripple currents simultaneously, by solving Maxwell’s equations using the finite element method (FEM) in the commercial software package COMSOL. It is observed that the instantaneous loss exhibits only one peak per cycle in the HTS CC subject to sinusoidal ripples, given that the amplitude of the ac ripples is smaller than approximately 20% of that of the dc current. This is a distinct contrast to the usual observation of two peaks per cycle in a HTS CC subject to ac currents only. The unique mechanism is also revealed, which is directly associated with the finding that, around any local minima of the applied ac ripples, the critical state of -J c is never reached at the edges of the HTS CC, as it should be according to the Bean model. When running further into the longer term, it is discovered that the ac ripple loss of the HTS CC in full-wave rectification decays monotonically, at a speed which is found to be insensitive to the frequency of the applied ripples within our targeted situations, to a relatively low level of approximately 1.38 × 10-4 W m-1 in around 1.7 s. Comparison between this level and other typical loss contributions in a HTS dc cable implies that ac ripple currents in HTS CCs should only be considered as a minor source of dissipation in superconducting dc

  13. The Application of Electrochemical Impedance Techniques in Analyzing the AC Response of Some Two-electron Transfer Dye Systems

    Directory of Open Access Journals (Sweden)

    Farouk Rashwan

    2005-01-01

    Full Text Available The Electrochemical Impedance Spectroscopic techniques (EIS were used to investigate the behavior of some dye compounds (quinoid systems characterized with 2e-transfer processes. For this purpose, Alizarin Red S (ARS, Alizarin Cyanine (AC, Alizarin Viridin (AV and carminic acid were chosen for the measurements. The EIS experiments were performed using a small AC amplitude (10 mV p-p in addition to a relatively wide frequency range (0.01 Hz ≤ f ≤ 105 Hz. The investigations were carried out at room temperature in aqueous media (HClO4, NaClO4 and KNO3 on the Hanging Mercury Drop Electrode (HMDE and for comparison one experiment only was measured in aprotic solvent (DMF on the Pt-disc electrode. The EIS diagrams of these systems were characterized in the complex plane by two fundamental observations, the first of which is a straight line crossing the real axis at an angle of 45° (or at least nearly so and the second one is two semicircles beside each other corresponding to high-frequency and low-frequency regions, which are implying the presence of well-separated time constants. The EIS characteristic parameters for these dye systems were calculated and discussed.

  14. Analysis of Bifurcation and Nonlinear Control for Chaos in Gear Transmission System

    Directory of Open Access Journals (Sweden)

    Wang Jingyue

    2013-07-01

    Full Text Available In order to study the bifurcation characteristics and control chaotic vibration of the gear transmission system. The complex dynamics characters of gear transmission system are studied. The dynamical equation and the state equation of gear transmission system are established according to Newton's rule. The route to chaos of the system is studied by the bifurcation diagram, phase portrait, time course diagram and Poincaré map. A method of controlling chaos by nonlinear feedback controller is developed to guide chaotic motions towards regular motions. Numerical simulation shows that with the increase of meshing stiffness, gear transmission system will be from the periodic motion to chaotic motion by doubling bifurcation, the effectiveness and feasibility of the strategy to get rid of chaos by stabilizing the related unstable periodic orbit.

  15. A Study on Collaborative Operation Method for a New Energy Type Dispersed Power Supply System by AC-EMAP Model

    Science.gov (United States)

    Hidese, Koichi; Takano, Ichiro; Nishikawa, Hisao; Sawada, Yoshio

    Application of a dispersed power supply system combined with a large scale photovoltaic system (PV), a fuel cell (FC) and an electric double layer capacitor (EDLC) is studied in this paper. This system is operated in autonomous mode, taking account of time delay characteristics of FC. The modified Euler type Moving Average Prediction (EMAP) model is improved using short time fast fourier transform (ST-FFT). The Adaptive Control type EMAP (AC-EMAP) model is introduced to reduce the capacity of EDLC. This system can meet the multi-quality electric power requirements of customers, and compensate voltage stability and uninterruptible power supply (UPS) function as well. Moreover, the required capacity of EDLC to compensate the fluctuation of both PV output and load demand is clarified by the simulation based on collaborative operation method by a prediction model using software MATLAB/Simulink.

  16. A.c. susceptibility study of CaCl2 doped copper–zinc ferrite system

    Indian Academy of Sciences (India)

    A Y Lipare; P N Vasambekar; A S Vaingankar

    2003-08-01

    Polycrystalline soft ferrites, Zn$_x$ Cu$_{1–x}$ Fe2O4 ( = 0.30, 0.50, 0.70, 0.80 and 0.90), doped with controlled amount of calcium chloride (CaCl2) were prepared by standard ceramic route and studied for a.c. susceptibility. X-ray diffraction studies of the compositions reveal formation of single-phase cubic spinel. The values of lattice constant increase as doping percentage of CaCl2 increased from 0.01% to 0.05% and afterwards decrease slightly. The presence of chlorine ions is confirmed by absorption peak in far IR spectra near 650 cm-1 for all the samples. The variation of a.c. susceptibility with temperature shows the existence of single domain structure for = 0.3 and exhibits transition from single domain to multidomain structure with increased Ca2+ contents from 0.01 to 0.1%. The composition, = 0.5, shows multidomain structure independent of Ca2+ content. The samples for = 0.70, 0.80 and 0.90 show paramagnetic behaviour at and above room temperature.

  17. Research and Development of Engine-Generator Set Control System for Tracked Vehicle Electric Transmission System

    Institute of Scientific and Technical Information of China (English)

    HUANG Ying; HUANG Qian; SUN Feng-chun; LIU Bo-lan; LIU Jia

    2007-01-01

    As an energy generating equipment, the engine-generator set supplies power to the electric transmission. Therefore, its control is one of the key technologies of electric vehicles. Based on the discussion about the demands to the engine-generator set in tracked vehicles, the detailed function of engine-generator and the control strategy are determined. The hardware and software of the control system are also developed and tested in a prototype vehicle. The experiment results show that the control system has good reliability and can satisfy the power requirements of vehicles under all operating conditions.

  18. Control system of the physical simulation for the HVDC transmission system

    Science.gov (United States)

    Liu, Zheng; Huang, Tongyuan; Liu, Wei; Ai, Bing; Mou, Daohuai

    2007-12-01

    The intention of this paper is to present the control system of the physical simulation for the Three Gorges HVDC transmission system. It covers all essential control functions which are involved in the continuously working power flow control and power modulation including converter firing and pole current control. This system include two convert stations, They design the fault arbitrator for the dual-controller system based on fault-tolerant technology and figure-safety-comparing technology. The arbitrator can endure long working time with high reliability. Controller A and B not only works independent, but also can controlled by the master controller from CAN bus. At the same time, because the master controller is a industrial PC, we can easy adjust and enhance the functions. This characteristic is especially fit the physical simulation system.

  19. Evaluation of power system security and development of transmission pricing method

    Science.gov (United States)

    Kim, Hyungchul

    The electric power utility industry is presently undergoing a change towards the deregulated environment. This has resulted in unbundling of generation, transmission and distribution services. The introduction of competition into unbundled electricity services may lead system operation closer to its security boundaries resulting in smaller operating safety margins. The competitive environment is expected to lead to lower price rates for customers and higher efficiency for power suppliers in the long run. Under this deregulated environment, security assessment and pricing of transmission services have become important issues in power systems. This dissertation provides new methods for power system security assessment and transmission pricing. In power system security assessment, the following issues are discussed (1) The description of probabilistic methods for power system security assessment; (2) The computation time of simulation methods; (3) on-line security assessment for operation. A probabilistic method using Monte-Carlo simulation is proposed for power system security assessment. This method takes into account dynamic and static effects corresponding to contingencies. Two different Kohonen networks, Self-Organizing Maps and Learning Vector Quantization, are employed to speed up the probabilistic method. The combination of Kohonen networks and Monte-Carlo simulation can reduce computation time in comparison with straight Monte-Carlo simulation. A technique for security assessment employing Bayes classifier is also proposed. This method can be useful for system operators to make security decisions during on-line power system operation. This dissertation also suggests an approach for allocating transmission transaction costs based on reliability benefits in transmission services. The proposed method shows the transmission transaction cost of reliability benefits when transmission line capacities are considered. The ratio between allocation by transmission line

  20. A Study on the Application for Enhancing the Transmission Capability of the KEPCO Power System

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Han; Kwon, Tea Won; Whang, Jong Young; Lee, Gun Joon; Kim, Tae Hoon; Chang, Byung Hoon; Min, Wan Ki [Korea Electric Power Research Institute, Taejon (Korea, Republic of); Park, Young Moon; Park, Jong Gun [Seoul National University, Seoul (Korea, Republic of); Kim, Gun Joong [Chungnam National University, Taejon (Korea, Republic of); Oh, Tae Kwu; Choi, Kwu Hyung [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1996-12-31

    Investigation of stability for power system in 2000 year and 2006 year by using the analysis of real power system. Comparative investigation of the conventional transmission line upgrading methods such as HVDC, HOP, new conductor scheme. Investigation of FACTS, the recent transmission line upgrading method, with respect to the aspect of technique and cost and effect analysis when this method is applied to real power system. Development of the evaluation method of transmission type that should be considered when above method is applied to real power system with respect to aspect of technique and cost. Development of a long-range plan for the transmission capacity upgrading and the evaluation method of reliability. (author).

  1. Hybrid mathematical and rule-based system for transmission network planning in open access schemes

    Energy Technology Data Exchange (ETDEWEB)

    Kandil, M. S. [Electrical Department, Mansura University, (Egypt); EI-Debeiky, S. M. [Electrical Department, Ain Shams University, (Egypt); Hasanien, N. E. [Egyptian Electricity Authority, Studies and Researches Department, (Egypt)

    2001-09-01

    The paper presents a planning methodology using an application of a mathematical and a rule-based expert system (ES) to expand the transmission network in open access schemes. In this methodology, the ES suggests a realistic set of generation additions with proper economic signals to the participants, before proceeding with the transmission expansion. A feasible list of transmission alternatives is then assumed to accommodate the proposals for generation. A mathematical method is performed based on marginal cost allocation to optimise the location for the new generation and its transmission expansion scheme simultaneously for each alternative. The optimum alternative, which minimises the overall system's cost function and satisfies the future demand under different operating conditions, is obtained. The ES interacts with the power system planning tools to produce the optimum expansion plan. A practical application is given to demonstrate the effectiveness of the developed prototype system. (Author)

  2. Training-based Channel Estimation for Signal Equalization and OPM in 16-QAM Optical Transmission Systems

    DEFF Research Database (Denmark)

    Pittalà, Fabio; Hauske, Fabian N.; Ye, Yabin;

    2012-01-01

    Efficient channel estimation for signal equalization and OPM based on short CAZAC sequences with QPSK and 8PSK constellation formats is demonstrated in a 224-Gb/s PDM 16-QAM optical linear transmission system....

  3. Progress on advanced dc and ac induction drives for electric vehicles

    Science.gov (United States)

    Schwartz, H. J.

    1982-01-01

    Progress is reported in the development of complete electric vehicle propulsion systems, and the results of tests on the Road Load Simulator of two such systems representative of advanced dc and ac drive technology are presented. One is the system used in the DOE's ETV-1 integrated test vehicle which consists of a shunt wound dc traction motor under microprocessor control using a transistorized controller. The motor drives the vehicle through a fixed ratio transmission. The second system uses an ac induction motor controlled by transistorized pulse width modulated inverter which drives through a two speed automatically shifted transmission. The inverter and transmission both operate under the control of a microprocessor. The characteristics of these systems are also compared with the propulsion system technology available in vehicles being manufactured at the inception of the DOE program and with an advanced, highly integrated propulsion system upon which technology development was recently initiated.

  4. Interface of data transmission for a transcutaneous communication system using the human body as transmission medium.

    Science.gov (United States)

    Okamoto, Eiji; Kato, Yoshikuni; Seino, Kazuyuki; Mitamura, Yoshinori

    2012-03-01

    We have been developing a new transcutaneous communication system (TCS) that uses the human body as an electrical conductive medium. We studied an interface circuit of the TCS in order to optimize the leading data current into the human body effectively. Two types of LC circuits were examined for the interface circuit, one was an LC series-parallel circuit, and the other was a parallel-connected LC circuit. The LC series-parallel circuit connected to the body could be tuned to a resonant frequency, and the frequency was determined by the values of an external inductor and an external capacitor. Permittivity of the body did not influence the electrical resonance. Connection of the LC series-parallel circuit to the body degraded the quality factor Q because of the conductivity of the body. However, the LC parallel-connected circuit when connected to the body did not indicate electrical resonance. The LC series-parallel circuit restricts a direct current and a low-frequency current to flow into the body; thus, it can prevent a patient from getting a shock. According to the above results, an LC series-parallel circuit is an optimum interface circuit between the TCS and the body for leading data current into the body effectively and safely.

  5. The effect analysis of strain rate on power transmission tower-line system under seismic excitation.

    Science.gov (United States)

    Tian, Li; Wang, Wenming; Qian, Hui

    2014-01-01

    The effect analysis of strain rate on power transmission tower-line system under seismic excitation is studied in this paper. A three-dimensional finite element model of a transmission tower-line system is created based on a real project. Using theoretical analysis and numerical simulation, incremental dynamic analysis of the power transmission tower-line system is conducted to investigate the effect of strain rate on the nonlinear responses of the transmission tower and line. The results show that the effect of strain rate on the transmission tower generally decreases the maximum top displacements, but it would increase the maximum base shear forces, and thus it is necessary to consider the effect of strain rate on the seismic analysis of the transmission tower. The effect of strain rate could be ignored for the seismic analysis of the conductors and ground lines, but the responses of the ground lines considering strain rate effect are larger than those of the conductors. The results could provide a reference for the seismic design of the transmission tower-line system.

  6. A Series-LC-Filtered Active Damper with Grid Disturbance Rejection for AC Power-Electronics-Based Power Systems

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Pang, Ying; Loh, Poh Chiang;

    2015-01-01

    damper. Unlike an active power filter for mitigating low-frequency harmonics, the proposed damper dampens resonances at higher frequencies, whose values are dependent on interactions among multiple grid-connected converters and reactive elements of the system. Its control requirements are, therefore......-order resonant controller, in addition to the second-order resonant controller used for resonance damping. Experimental results obtained have confirmed the effectiveness of these controllers, and hence, the feasibility of the active damper.......This letter proposes an active damper with a series LC filter for suppressing resonances in an ac power-electronics-based power system. The added series filter capacitor helps to withstand most of the system voltage, hence, allowing a lower rated converter to be used for implementing the active...

  7. Controlled merging and annihilation of localised dissipative structures in an AC-driven damped nonlinear Schrödinger system

    Science.gov (United States)

    Jang, Jae K.; Erkintalo, Miro; Luo, Kathy; Oppo, Gian-Luca; Coen, Stéphane; Murdoch, Stuart G.

    2016-03-01

    We report studies of controlled interactions of localised dissipative structures in a system described by the AC-driven damped nonlinear Schrödinger equation (equivalent to the Lugiato-Lefever model). Extensive numerical simulations reveal a variety of interaction scenarios that are governed by the properties of the system driver, notably its gradients. In our experiments, performed with a nonlinear optical fibre (Kerr) resonator, the phase profile of the driver is used to induce interactions of the dissipative structures on demand. We observe both merging and annihilation of localised structures, i.e. interactions governed by the dissipative, out-of-equilibrium nature of the system. These interactions fundamentally differ from those typically found for conventional conservative solitons.

  8. System Design for Ocean Sensor Data Transmission Based on Inductive Coupling

    Science.gov (United States)

    Xu, Ming; Liu, Fei; Zong, Yuan; Hong, Feng

    Ocean observation is the precondition to explore and utilize ocean. How to acquire ocean data in a precise, efficient and real-time way is the key question of ocean surveillance. Traditionally, there are three types of methods for ocean data transmission: underwater acoustic, GPRS via mobile network and satellite communication. However, none of them can meet the requirements of efficiency, accuracy, real-time and low cost at the same time. In this paper, we propose a new wireless transmission system for underwater sensors, which established on FGR wireless modules, combined with inductive coupling lab and offshore experiments confirmed the feasibility and effectiveness of the proposed wireless transmission system.

  9. Electrical transmission systems and smart grids selected entries from the encyclopedia of sustainability science and technology

    CERN Document Server

    Begovic, Miroslav M

    2012-01-01

    Electric transmission networks are among the largest human-made engineering systems: For example, the transmission network in the United States covers over 300,000 km of lines and is served by 500 companies (electric utilities). In sharp contrast to the very incremental developments of the last century, transmission and control technologies experienced a major breakthrough at the beginning of the 21st century. The rapid growth of new energy generation technologies (renewables), significant advances in information processing applied to system monitoring, planning, operation, control, and protec

  10. Transmission Dynamics of a Driven Two-Level System Dissipated by Leads

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ping; FAN Wen-Bin; ZHAO Xian-Geng

    2001-01-01

    We study the transmission dynamics of a driven two-level system dissipated by the two leads. Using the nonequilibrium Green function, we derive an analytical transmission formula for an electron incident from the left lead,through the double quantum dots, to the right lead. The Landauer-type conductance and current are also given.A discussion of the internal tunnelling dynamics reveals crucial effects of the localization and delocalization on the transport of the system.

  11. The Numerical Analysis of Transmission Tower-Line System Wind-Induced Collapsed Performance

    OpenAIRE

    Zhuoqun Zhang; Hongnan Li; Gang Li; Wenming Wang; Li Tian

    2013-01-01

    The numerical simulation of transmission tower-line systems' progressive collapse performance is considered as a major research hotspot and significant project, due to the increasing number of wind-induced collapse accidents recently. In this study, the finite element models for single tower and transmission tower-line system were established to simulate wind-induced progressive collapse by birth-to-death element technique in ABAQUS/Explicit. The wind field, based on the Kaimal fluctuating wi...

  12. Simulation on Dual-stream Transmission System of Unmanned Tracked Armored Vehicle Using ADAMS

    Directory of Open Access Journals (Sweden)

    Sun Wei

    2015-01-01

    Full Text Available For the dual-stream transmission system of unmanned tracked armored vehicle, simulation analysis is carried out. Using SolidWorks to establish three-dimensional model of its chassis, the result of the simulation is processed in AdAMS/Solver. The simulation results are showed in lines. Comparative analysis for each simulation lines is conducted, and it verifies the feasibility of the dual-stream transmission system.

  13. Modular VSC converter based HVDC power transmission from offshore wind power plant: Compared to the conventional HVAC system

    DEFF Research Database (Denmark)

    Sharma, Ranjan; Rasmussen, Tonny Wederberg; Jensen, Kim Høj;

    2010-01-01

    power transmission options with HVDC systems are under consideration. In this paper, a comparison between a conventional HVAC transmission system and a HVDC system equipped with modular voltage source converters is provided. The comparison is based on the total energy transmission capability...

  14. Transmission systems expansion planning considering security and generation programming plans

    OpenAIRE

    Irenio de Jesus Silva Junior

    2005-01-01

    Resumo: Este trabalho apresenta algumas propostas para solucionar o problema de planejamento da expansão de sistemas de transmissão, estático e multiestágio, considerando restrições de segurança - critério de segurança (n_1), assim como para o planejamento da expansão de um sistema elétrico que satisfaça simultaneamente vários planos de programação da geração pré-especificados. Visando superar deficiências na determinação de soluções ótimas para sistemas de grande porte quando se usa métodos ...

  15. Massive WDM and TDM Soliton Transmission Systems : a ROSC Symposium

    CERN Document Server

    2002-01-01

    This book summarizes the proceedings of the invited talks presented at the “International Symposium on Massive TDM and WDM Optical Soliton Tra- mission Systems” held in Kyoto during November 9–12, 1999. The symposium is the third of the series organized by Research Group for Optical Soliton C- munications (ROSC) chaired by Akira Hasegawa. The research group, ROSC, was established in Japan in April 1995 with a support of the Japanese Ministry of Post and Telecommunications to promote collaboration and information - change among communication service companies, communication industries and academic circles in the theory and application of optical solitons. The symposium attracted enthusiastic response from worldwide researchers in the field of soliton based communications and intensive discussions were made. In the symposium held in 1997, new concept of soliton transmission based on dispersion management of optical fibers were presented. This new soliton is now called the dispersion managed soliton. The p...

  16. Single Ended Fault Location Estimation for EHV Transmission Systems

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qing-chao张庆超; LI Hui李晖; D. W. P. Thomas

    2004-01-01

    A novel numerical algorithm for fault location estimation of single-phase-to-earth fault on EHV transmission lines is presented in this paper. The method is based on one-terminal voltage and current data and is used in a procedure that provides the automatic determination of faulted types and phases, rather than requires engineer to specify them. The loop and nodal equations comparing the faulted phase to non-faulted phases of multi-parallel lines are introduced in the fault location estimation models, in which source impedance of remote end is not involved. Precise algorithms of locating fault are derived. The effect of load flow and fault resistance,on the location accuracy, are effectively eliminated. The algorithms are demonstrated by digital computer simulations.

  17. A Novel Modulation Function-Based Control of Modular Multilevel Converters for High Voltage Direct Current Transmission Systems

    Directory of Open Access Journals (Sweden)

    Majid Mehrasa

    2016-10-01

    Full Text Available In this paper, a novel modulation function-based method including analyses of the modulation index and phase is proposed for operation of modular multilevel converters (MMCs in high voltage direct current (HVDC transmission systems. The proposed modulation function-based control technique is developed based on thorough and precise analyses of all MMC voltages and currents in the a-b-c reference frame in which the alternating current (AC-side voltage is the first target to be obtained. Using the AC-side voltage, the combination of the MMC upper and lower arm voltages is achieved as the main structure of the proposed modulation function. The main contribution of this paper is to obtain two very simple new modulation functions to control MMC performance in different operating conditions. The features of the modulation function-based control technique are as follows: (1 this control technique is very simple and can be easily achieved in a-b-c reference frame without the need of using Park transformation; and (2 in addition, the inherent properties of the MMC model are considered in the proposed control technique. Considering these properties leads to constructing a control technique that is robust against MMC parameters changes and also is a very good tracking method for the components of MMC input currents. These features lead to improving the operation of MMC significantly, which can act as a rectifier in the HVDC structure. The simulation studies are conducted through MATLAB/SIMULINK software, and the results obtained verify the effectiveness of the proposed modulation function-based control technique.

  18. Cascading failures in ac electricity grids

    Science.gov (United States)

    Rohden, Martin; Jung, Daniel; Tamrakar, Samyak; Kettemann, Stefan

    2016-09-01

    Sudden failure of a single transmission element in a power grid can induce a domino effect of cascading failures, which can lead to the isolation of a large number of consumers or even to the failure of the entire grid. Here we present results of the simulation of cascading failures in power grids, using an alternating current (AC) model. We first apply this model to a regular square grid topology. For a random placement of consumers and generators on the grid, the probability to find more than a certain number of unsupplied consumers decays as a power law and obeys a scaling law with respect to system size. Varying the transmitted power threshold above which a transmission line fails does not seem to change the power-law exponent q ≈1.6 . Furthermore, we study the influence of the placement of generators and consumers on the number of affected consumers and demonstrate that large clusters of generators and consumers are especially vulnerable to cascading failures. As a real-world topology, we consider the German high-voltage transmission grid. Applying the dynamic AC model and considering a random placement of consumers, we find that the probability to disconnect more than a certain number of consumers depends strongly on the threshold. For large thresholds the decay is clearly exponential, while for small ones the decay is slow, indicating a power-law decay.

  19. System Reliability Evaluation of Data Transmission in Commercial Banks with Multiple Branches

    Directory of Open Access Journals (Sweden)

    Yi-Kuei Lin

    2014-01-01

    Full Text Available The main purpose of this paper is to assess the system reliability of electronic transaction data transmissions made by commercial banks in terms of stochastic flow network. System reliability is defined as the probability of demand satisfaction and it can be used to measure quality of service. In this paper, we study the system reliability of data transmission from the headquarters of a commercial bank to its multiple branches. The network structure of the bank and the probability of successful data transmission are obtained through the collection of real data. The system reliability, calculated using the minimal path method and the recursive sum of disjoint products algorithm, provides banking managers with a view to comprehend the current state of the entire system. Besides, the system reliability can be used not only as a measurement of quality of service, but also an improvement reference of the system by adopting sensitivity analysis.

  20. [Study on transmission efficiency of interference system in spatially modulated Fourier transform spectrometer].

    Science.gov (United States)

    Lü, Jin-Guang; Liang, Jing-Qiu; Liang, Zhong-Zhu; Qin, Yu-Xin; Tian, Chao

    2013-03-01

    The reflection of the optic system surface and the absorption of the infrared material could reduce the transmission of the incident light in spatially modulated Fourier transform infrared spectrometer. Through the calculation of the transmission function of the interference system and the simulation of the interferogram image and recovered spectrum affected by transmission function, it was indicated that the contrast of the interferogram image declined and the spectral line intensity weakened. The theoretical analysis shows that the contrast of the interferogram image was related to the intensity reflectance of the anti-reflection film, and the attenuation of the spectrum was determined by transmission efficiency concerned with intensity reflectance R1 of the anti-reflection film, intensity reflectance R2 of the beam splitter film, and the absorption coefficient. By means of the analysis and argumentation, the absorption of the material could be ignored in our investigative wave band. So the transmission efficiency was determined only by R1 and R2. Then taking the transmission efficiency as the design target, according to the transmission required by system, the tolerance of the R1 and R2 could be gained.

  1. LQR Feedback Control Development for Wind Turbines Featuring a Digital Fluid Power Transmission System

    DEFF Research Database (Denmark)

    Pedersen, Niels Henrik; Johansen, Per; Andersen, Torben O.

    2016-01-01

    Research within digital fluid power (DFP) transmissions is receiving an increased attention as an alternative to conventional transmission technologies. The use of DFP displacement machines entail a need for applicable control algorithms. However, the design and analysis of controllers...... for such digital systems are complicated by its non-smooth behavior. In this paper a control design approach for a digital displacement machine® is proposed and a performance analysis of a wind turbine using a DFP transmission is presented. The performance evaluation is based on a dynamic model of the transmission...... invariant model. Using full-field flow wind profiles as input, the design approach and control performance is verified by simulation in the dynamic model of the wind turbine featuring the DFP transmission. Additionally, the performance is compared to that of the conventional NREL reference turbine...

  2. Long-Haul Dense Space Division Multiplexed Transmission over Low-Crosstalk Heterogeneous 32-Core Transmission Line Using Partial Recirculating Loop System

    DEFF Research Database (Denmark)

    Mizuno, Takayuki; Shibahara, Kohki; Ye, Feihong

    2017-01-01

    In this paper, we present long-haul 32-core dense space division multiplexed (DSDM) unidirectional transmission over a single-mode multicore transmission line. We developed a low-crosstalk heterogeneous 32-core fiber with a square lattice arrangement, and a novel partial recirculating loop system...

  3. Cost estimation of HVDC transmission system of Bangka’s NPP candidates

    Energy Technology Data Exchange (ETDEWEB)

    Liun, Edwaren, E-mail: edwaren@batan.go.id; Suparman, E-mail: edwaren@batan.go.id [Centre for Nuclear Energy Development, National Nuclear Energy Agency of Indonesia (Indonesia)

    2014-09-30

    Regarding nuclear power plant development in Bangka Island, it can be estimated that produced power will be oversupply for the Bangka Island and needs to transmit to Sumatra or Java Island. The distance between the regions or islands causing considerable loss of power in transmission by alternating current, and a wide range of technical and economical issues. The objective of this paper addresses to economics analysis of direct current transmission system to overcome those technical problem. Direct current transmission has a stable characteristic, so that the power delivery from Bangka to Sumatra or Java in a large scale efficiently and reliably can be done. HVDC system costs depend on the power capacity applied to the system and length of the transmission line in addition to other variables that may be different.

  4. Load speed regulation in compliant mechanical transmission systems using feedback and feedforward control actions.

    Science.gov (United States)

    Raul, P R; Dwivedula, R V; Pagilla, P R

    2016-07-01

    The problem of controlling the load speed of a mechanical transmission system consisting of a belt-pulley and gear-pair is considered. The system is modeled as two inertia (motor and load) connected by a compliant transmission. If the transmission is assumed to be rigid, then using either the motor or load speed feedback provides the same result. However, with transmission compliance, due to belts or long shafts, the stability characteristics and performance of the closed-loop system are quite different when either motor or load speed feedback is employed. We investigate motor and load speed feedback schemes by utilizing the singular perturbation method. We propose and discuss a control scheme that utilizes both motor and load speed feedback, and design an adaptive feedforward action to reject load torque disturbances. The control algorithms are implemented on an experimental platform that is typically used in roll-to-roll manufacturing and results are shown and discussed.

  5. High-voltage transmission tower-line system subjected to disaster loads

    Institute of Scientific and Technical Information of China (English)

    LI Hongnan; BAI Haifeng

    2006-01-01

    The high-voltage power transmission system is an important lifeline structure. It is significant for wide researches on the features and ability of the system subjected to earthquake and environmental loads. The promising prosperity of the system has been demonstrated around the world. The corresponding advances of the system with respect to the mechanism of loading action, analytical methods, experimental research measurements, structural vibration control, fatigue damage, lifetime prediction, and design methods are comprehensively discussed herein. Finally, further research work on dynamic response characteristics of high-voltage transmission towerline system in the near future is predicted.

  6. 47 CFR 73.1350 - Transmission system operation.

    Science.gov (United States)

    2010-10-01

    ... regarding antenna tower lighting, and § 73.69 regarding the parameters of an AM directional antenna system... system tolerances, see § 73.62; (2) AM directional antenna monitoring points, see § 73.158; (3) TV...

  7. Microwave power transmission system workshop, session on solid state

    Science.gov (United States)

    Finnell, W.

    1980-01-01

    The development of solid state technology for solar power satellite systems is briefly addressed. The economic advantages of solid state based systems are listed along with some conclusions and issues regarding specific design concepts.

  8. Electrical Collection and Transmission Systems for Offshore Wind Power: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Green, J.; Bowen, A.; Fingersh, L.J.; Wan, Y.

    2007-03-01

    The electrical systems needed for offshore wind farms to collect power from wind turbines--and transmit it to shore--will be a significant cost element of these systems. This paper describes the development of a simplified model of the cost and performance of such systems.

  9. 模块化双向AC/DC变换器并联系统无缝切换控制%Seamless Switching Control for Modular Bi-directional AC/DC Converter Parallel Systems

    Institute of Scientific and Technical Information of China (English)

    张犁; 吴田进; 冯兰兰; 孙凯; 邢岩

    2012-01-01

    研究模块化双向AC/DC变换器并联运行系统,分析指出现有单模块双向运行控制方法引起各并联模块的功率流向不一致的问题;研究系统功率流与直流母线电压变化趋势的内在联系,提出一种模块化AC/DC变换器的双向运行控制方法,分别采用正向和负向电压调节器以保证各并联模块的功率流向一致;整流和逆变状态以不同的直流母线电压运行、自然区分两种功率流向。提出的控制方法可以实现各并联模块整流与逆变之间的无缝切换。详细分析系统稳定性,并指出多模块并联对系统动态特性有所改善;给出关键参数的设计准则。搭建实验验证系统,进行稳态和动态实验。实验结果证明了所提出控制方法的可行性和有效性。%The issue of inconsistent power flow among modular bi-directional AC/DC converters in parallel operation with the conventional control was analyzed.The inherent relationship between system power flow and the trend of the DC bus voltage was researched and a bi-directional operation control for the modular AC/DC converter parallel system was proposed.The consistent power flow of each module is achieved by utilizing a positive and a negative DC bus voltage regulators.Power flows of rectification and inversion are distinguished naturally with different DC bus voltages,and seamless switching between rectification and inversion was also realized.The stability of the modular AC/DC converter parallel system was analyzed in detail with the design principle of the key parameter given.A prototype system was built and both of the steady-state and dynamic experimental results were presented to verify the effectiveness of the proposed system and control method.

  10. Pulse position modulation for a subcarrier-multiplexed optical fiber transmission system

    Science.gov (United States)

    Wickramasinghe, V. R.; Ghassemlooy, Zabih F.

    1996-11-01

    Subcarrier multiplexed (SCM) optical network s offer a near to medium term alternative solution over high cost, evolving digital technology to distribute broadband services. Majority of existing systems are based on analogue optical transmission techniques and their principle disadvantage is the sensitivity to noise and system nonlinearities. Therefore, conventional SCM systems impose stringent noise and linearity requirements and as a result their performance is limited. A simple and attractive solution is to introduce an appropriate second stage modulator in order to improve the receiver sensitivity, hence the system performance.In this paper a SCM optical transmission system employing pulse position modulation as a second stage modulator, for transmission of video, audio and data channels is reported. Signal to noise ratio measurements obtained shows an improvement in optical receiver sensitivity compared with standard SCM systems.

  11. Interior point algorithm-based power flow optimisation of a combined AC and DC multi-terminal grid

    Directory of Open Access Journals (Sweden)

    Farhan Beg

    2015-01-01

    Full Text Available The high cost of power electronic equipment, lower reliability and poor power handling capacity of the semiconductor devices had stalled the deployment of systems based on DC (multi-terminal direct current system (MTDC networks. The introduction of voltage source converters (VSCs for transmission has renewed the interest in the development of large interconnected grids based on both alternate current (AC and DC transmission networks. Such a grid platform also realises the added advantage of integrating the renewable energy sources into the grid. Thus a grid based on DC MTDC network is a possible solution to improve energy security and check the increasing supply demand gap. An optimal power solution for combined AC and DC grids obtained by the solution of the interior point algorithm is proposed in this study. Multi-terminal HVDC grids lie at the heart of various suggested transmission capacity increases. A significant difference is observed when MTDC grids are solved for power flows in place of conventional AC grids. This study deals with the power flow problem of a combined MTDC and an AC grid. The AC side is modelled with the full power flow equations and the VSCs are modelled using a connecting line, two generators and an AC node. The VSC and the DC losses are also considered. The optimisation focuses on several different goals. Three different scenarios are presented in an arbitrary grid network with ten AC nodes and five converter stations.

  12. Investigations and system design for simultaneous energy and data transmission through inductively coupled resonances

    Science.gov (United States)

    Schmidt, C.; Lloret Fuentes, E.; Buchholz, M.

    2015-11-01

    Wireless Power Transfer (WPT) with simultaneous data transmission through coupled magnetic resonators is investigated in this paper. The development of this system is dedicated to serve as a basis for applications in the field of Ambient Assisted Living (AAL), for example tracking vital parameters remotely, charge and control sensors and so on. Due to these different scenarios we consider, it is important to have a system which is reliable under the circumstance of changing positioning of the receiving device. State of the art radio systems would be able to handle this. Nevertheless, energy harvesting from far field sources is not sufficient to power the devices additionally on mid-range distances. For this reason, coupled magnetic resonant circuits are proposed as a promising alternative, although suffering from more complex positioning dependency. Based on measurements on a simple prototype system, an equivalent circuit description is used to model the transmission system dependent on different transmission distances and impedance matching conditions. Additionally, the simulation model is used to extract system parameters such as coupling coefficients, coil resistance and self-capacitance, which cannot be calculated in a simple and reliable way. Furthermore, a mathematical channel model based on the schematic model has been built in MATLAB©. It is used to point out the problems occurring in a transmission system with variable transmission distance, especially the change of the passband's centre frequency and its bandwidth. Existing solutions dealing with this distance dependent behaviour, namely the change of the transmission frequency dependent on distance and the addition of losses to the resonators to increase the bandwidth, are considered as not inventive. First, changing the transmission frequency increases the complexity in the data transmission system and would use a disproportional total bandwidth compared to the actually available bandwidth

  13. Optimisation of Transmission Systems by use of Phase Shifting Transformers

    Energy Technology Data Exchange (ETDEWEB)

    Verboomen, J.

    2008-10-13

    In this thesis, transmission grids with PSTs (Phase Shifting Transformers) are investigated. In particular, the following goals are put forward: (a) The analysis and quantification of the impact of a PST on a meshed grid. This includes the development of models for the device; (b) The development of methods to obtain optimal coordination of several PSTs in a meshed grid. An objective function should be formulated, and an optimisation method must be adopted to solve the problem; and (c) The investigation of different strategies to use a PST. Chapter 2 gives a short overview of active power flow controlling devices. In chapter 3, a first step towards optimal PST coordination is taken. In chapter 4, metaheuristic optimisation methods are discussed. Chapter 5 introduces DC load flow approximations, leading to analytically closed equations that describe the relation between PST settings and active power flows. In chapter 6, some applications of the methods that are developed in earlier chapters are presented. Chapter 7 contains the conclusions of this thesis, as well as recommendations for future work.

  14. Effect of Tooth Profile Modification on Vibration of Power Split Gear Transmission System

    Institute of Scientific and Technical Information of China (English)

    He Lin

    2016-01-01

    Based on Newton's second law, the bend⁃torsion⁃shaft coupling nonlinear dynamic model and equations of power split gear transmission system are established. According to the principle of tooth profile modification, the tooth profile modification is considered as time⁃varying gear backlash function acting along the line of action. Then the dynamic functions are solved by using Runge⁃Kutta numerical method. After analyzing the effect of tooth profile modification quantity( TPMQ) and relative tooth profile modification length( TPML) to the nonlinear dynamic characteristics of power split gear transmission, the following conclusions are drawn:①The TPMQ of a certain stage transmission affects the vibration of its own stage more significantly than the other stage, and the coupling effect between two stages can be ignored usually in the modification design;②If the first stage TPMLs are less than 0.3, the influence of the first stage TPMLs to the first stage transmission vibration is much more greatly than the influence of the second stage TPMLs to the first stage transmission vibration, or else both the first and second stage TPMLs affect the first stage transmission vibration largely. The same is true for the second stage TPMLs, and the cutoff value is 0. 2; ③The TPMQ affects the vibration of power split gear transmission system more principally than the TPML, and should be top⁃priority in the modification design.

  15. Expedience of application of MIMO systems of digital communication for complex chaotic signal transmission

    OpenAIRE

    Vasyuta, K. S.; Zakharchenko, I. V.; Ozerov, S. V.

    2015-01-01

    The paper discusses the expediency of using MIMO digital systems for transmission of chaotic signals as a way of partial solution of electromagnetic compatibility of perspective broadband communication systems with an existing class of narrow-band radio-technical systems.

  16. Optimum Method for RC Snubber of High-Capacity AC-DC Converter in Ship Electric Propulsion System%船舶大功率AC-DC变换器阻容缓冲器优化方法

    Institute of Scientific and Technical Information of China (English)

    赵凯岐; 张殿华; 兰海; 岳文杰; 张强

    2011-01-01

    In design process of high-capacity AC-DC converter in ship electric propulsion system, the RC snubber circuit should be connected to the thyristor in parallel in order to absorb the energy generated at the moment of thyristor switching and suppress overvoltage impulses and high voltage change rate du/dt.However, parameter selection, which is generally depended on empirical formula, sometimes leads to a rather great error. Once the selection of protection parameters is unreasonable, a high spike voltage is likely to occur and render power electronic components will be easily damaged, which threatens the operation safety of equipments. In this paper, a new optimal design method of RC snubber circuit is proposed for thyristor in high-capacity AC-DC converter, R and C parameters and resistor power is deduced more accurately, and the reliability of the AC-DC converter is improved as a result. Numerical simulations and physical experiments are conducted to verify the feasibility and viability of the method.%船舶电力推进系统大功率AC-DC变换器设计时,必须在晶闸管的两端并联阻容缓冲器,以吸收器件关断过程反向恢复电流的能量,抑制高的过电压冲击及高的电压应力du/dt.但是,阻容参数的设计大多依靠经验公式,参数选取有时产生很大偏差,一旦选取不合理,便会产生很高的尖峰过电压,造成电力电子器件的损坏,影响系统安全运行.针对大功率AC-DC变换器晶闸管阻容缓冲器进行研究,提出了阻容缓冲器优化设计方法,推导出较精确的阻容参数值和电阻的功率,提高大功率AC-DC变换器的可靠性,仿真及实验验证了本方法的可行性.

  17. Optimal transmission strategy for spatially correlated MIMO systems with channel statistical information

    Institute of Scientific and Technical Information of China (English)

    ZHAO Zhen-shan; XU Guo-zhi

    2007-01-01

    In real multiple-input multiple-output (MIMO) systems, the perfect channel state information (CSI) may be costly or impossible to acquire. But the channel statistical information can be considered relatively stationary during long-term transmission.The statistical information can be obtained at the receiver and fed back to the transmitter and do not require frequent update. By exploiting channel mean and covariance information at the transmitter simultaneously, this paper investigates the optimal transmission strategy for spatially correlated MIMO channels. An upper bound of ergodic capacity is derived and taken as the performance criterion. Simulation results are also given to show the performance improvement of the optimal transmission strategy.

  18. Transmission Needs In A Fully Renewable Pan-European Electricity System

    DEFF Research Database (Denmark)

    Rodriguez, Rolando A.; Bruun Andresen, Gorm; Becker, Sarah;

    2012-01-01

    Based on high-resolution weather and electrical load data, the transmission needs for a fully renewable pan-European electricity system are determined. The ideal cross-border transmission capacities turn out to be a factor 10 larger than those of today. A reduction of cross-border transmission...... capacities lead to a non-linear increase of balancing needs. A good compromise turns out to be a capacity layout, which is a factor 5 larger than today’s one. On average each country will only be able to import / export 40% of its residual demand / renewable excess generation....

  19. Design, control and application of modular multilevel converters for HVDC transmission systems

    CERN Document Server

    Sharifabadi, Kamran; Nee, Hans-Peter; Norrga, Staffan; Teodorescu, Remus

    2016-01-01

    Design, Control and Application of Modular Multilevel Converters for HVDC Transmission Systems is a comprehensive guide to semiconductor technologies applicable for MMC design, component sizing control, modulation, and application of the MMC technology for HVDC transmission. Separated into three distinct parts, the first offers an overview of MMC technology, including information on converter component sizing, Control and Communication, Protection and Fault Management, and Generic Modelling and Simulation. The second covers the applications of MMC in offshore WPP, including planning, technical and economic requirements and optimization options, fault management, dynamic and transient stability. Finally, the third chapter explores the applications of MMC in HVDC transmission and Multi Terminal configurations, including Supergrids.

  20. Design of the Eelectron Cyclotron Resonance Heating Transmission System for HL-2A

    Institute of Scientific and Technical Information of China (English)

    周俊; 刘永

    2004-01-01

    HL-2A will be equipped with a 75 GHz/1 MW/1s electron cyclotron resonance heating (ECRH) system. The paper describes the design of the transmission system, which is made up of a transmission line, an equatorial launcher and a measureing system. The paper describes in detail the design of main components of the system such as, waveguides, ellipsoidal surface mirrors, chemical vapor (CVD) diamond window, steering mirror, and new directional coupler with a k-spectrometer. The newly-designed launcher can make the beam steer poloidally to deposit energy in different locations.

  1. Coordinated Transmissions to Direct and Relayed Users in Wireless Cellular Systems

    DEFF Research Database (Denmark)

    Thai, Chan; Popovski, Petar; Kaneko, Megumi

    2011-01-01

    The ideas of wireless network coding at the physical layer promise high throughput gains in wireless systems with relays and multi–way traffic flows. This gain can be ascribed to two principles: (1) joint transmission of multiple communication flows and (2) usage of a priori information to cancel...... the interference. In this paper we use these principles to devise new transmission schemes in wireless cellular systems that feature both users served directly by the base stations (direct users) and users served through relays (relayed users). We present four different schemes for coordinated transmission...... of uplink and downlink traffic in which one direct and one relayed user are served. These schemes are then used as building blocks in multi–user scenarios, where we present several schemes for scheduling pairs of users for coordinated transmissions. The optimal scheme involves exhaustive search of the best...

  2. The design and analysis of channel transmission communication system of XCTD profiler

    Science.gov (United States)

    Zheng, Yu; Wang, Xiao-Rui; Jin, Xiang-Yu; Song, Guo-Min; Shang, Ying-Sheng; Li, Hong-Zhi

    2016-10-01

    In this paper, a channel transmission communication system of expendable conductivity-temperature-depth is established in accordance to the operation characteristics of the transmission line to more accurately assess the characteristics of deep-sea abandoned profiler channel. The wrapping inductance is eliminated to maximum extent through the wrapping pattern of the underwater spool and the overwater spool and the calculation of the wrapping diameter. The feasibility of the proposed channel transmission communication system is verified through theoretical analysis and practical measurement of the transmission signal error rate in the amplitude shift keying (ASK) modulation. The proposed design provides a new research method for the channel assessment of complex abandoned measuring instrument and an important experiment evidence for the rapid development of the deep-sea abandoned measuring instrument.

  3. The design and analysis of channel transmission communication system of XCTD profiler.

    Science.gov (United States)

    Zheng, Yu; Wang, Xiao-Rui; Jin, Xiang-Yu; Song, Guo-Min; Shang, Ying-Sheng; Li, Hong-Zhi

    2016-10-01

    In this paper, a channel transmission communication system of expendable conductivity-temperature-depth is established in accordance to the operation characteristics of the transmission line to more accurately assess the characteristics of deep-sea abandoned profiler channel. The wrapping inductance is eliminated to maximum extent through the wrapping pattern of the underwater spool and the overwater spool and the calculation of the wrapping diameter. The feasibility of the proposed channel transmission communication system is verified through theoretical analysis and practical measurement of the transmission signal error rate in the amplitude shift keying (ASK) modulation. The proposed design provides a new research method for the channel assessment of complex abandoned measuring instrument and an important experiment evidence for the rapid development of the deep-sea abandoned measuring instrument.

  4. Hole-assisted multicore optical fiber for next generation telecom transmission systems

    Science.gov (United States)

    Ziolowicz, A.; Szymanski, M.; Szostkiewicz, L.; Tenderenda, T.; Napierala, M.; Murawski, M.; Holdynski, Z.; Ostrowski, L.; Mergo, P.; Poturaj, K.; Makara, M.; Slowikowski, M.; Pawlik, K.; Stanczyk, T.; Stepien, K.; Wysokinski, K.; Broczkowska, M.; Nasilowski, T.

    2014-08-01

    We present a multicore fiber dedicated for next generation transmission systems. To overcome the issue of multicore fibers' integration with existing transmission systems, the fiber is designed in such a way that the transmission parameters for each core (i.e., chromatic dispersion, attenuation, bending loss, etc.) are in total accordance with the obligatory standards for telecommunication single core fibers (i.e., ITU-T G.652 and G.657). We show the results of numerical investigations and measurements carried out for the fabricated fiber, which confirm low core-to-core crosstalk and compatibility with standard single-core single-mode transmission links making the fiber ready for implementation in the near future.

  5. Research on WDM optical fiber transmission system based on fiber Raman amplifier

    Institute of Scientific and Technical Information of China (English)

    Fei Xue(薛飞); Kun Qiu(邱昆); Yue Chen(陈玥)

    2003-01-01

    After wavelength division multiplexing (WDM) optical fiber transmission system based on fiber Raman amplifier (FRA) is investigated in detail, the influence of the collocation of dispersion compensation fiber (DCF), the dispersion coefficient, dispersion slope (DS), effective core area, nonlinear index, length of FRA, launch power and the bandwidth of Bessel filter on bit error rate (BER) is deduced. The influence of Rayleigh backscattering noise on optical signal noise ratio (OSNR) is also investigated, which affects the performance of long haul transmission badly. The result indicates that the broadband long haul transmission can be realized through the reasonable design of the fiber. The result is useful to the optimal design of the WDM optical fiber transmission system based on FRA.

  6. Coordinated Transmissions to Direct and Relayed Users in Wireless Cellular Systems

    CERN Document Server

    Thai, Chan Dai Truyen; Kaneko, Megumi; de Carvalho, Elisabeth

    2010-01-01

    The ideas of wireless network coding at the physical layer promise high throughput gains in wireless systems with relays and multi-way traffic flows. This gain can be ascribed to two principles: (1) joint transmission of multiple communication flows and (2) usage of \\emph{a priori} information to cancel the interference. In this paper we use these principles to devise new transmission schemes in wireless cellular systems that feature both users served directly by the base stations (direct users) and users served through relays (relayed users). We present four different schemes for \\emph{coordinated transmission} of uplink and downlink traffic in which one direct and one relayed user are served. These schemes are then used as building blocks in multi-user scenarios, where we present several schemes for scheduling pairs of users for coordinated transmissions. The optimal scheme involves exhaustive search of the best user pair in terms of overall rate. We propose several suboptimal scheduling schemes, which perf...

  7. Analysis of Basic Transmission Networks for Integrated Ship Control Systems

    DEFF Research Database (Denmark)

    Hansen, T.N.; Granum-Jensen, M.

    1993-01-01

    Description of a computer network for Integrated Ship Control Systems which is going to be developed as part of an EC-project. Today equipment of different make are not able to communicate with each other because most often each supplier of ISC systems has got their own proprietary network.....

  8. Kansas Communication and Instruction System through Fiber-Optic Transmission.

    Science.gov (United States)

    Kansas State Dept. of Education, Topeka.

    Schools and communities will restructure as they move into the next decade. The success of this restructuring will be dependent upon access to and sharing of quality teaching and information through an expanded communication system. One of the major two-way interactive technologies is the fiber-optic cable: a delivery system that will provide…

  9. Guidelines for transient analysis in water transmission and distribution systems

    NARCIS (Netherlands)

    Pothof, I.W.M.; Karney, B.W.

    2012-01-01

    All water systems leak, and many supply systems do so considerably, with water losses typically of approximately 20% of the water production. The IWA Water Loss Task Force aims for a significant reduction of annual water losses by drafting documents to assist practitioners and others to prevent, mon

  10. Guidelines for transient analysis in water transmission and distribution systems

    NARCIS (Netherlands)

    Pothof, I.W.M.; Karney, B.W.

    2012-01-01

    All water systems leak, and many supply systems do so considerably, with water losses typically of approximately 20% of the water production. The IWA Water Loss Task Force aims for a significant reduction of annual water losses by drafting documents to assist practitioners and others to prevent,

  11. Precision-analog fiber-optic transmission system

    Energy Technology Data Exchange (ETDEWEB)

    Stover, G.

    1981-06-01

    This article describes the design, experimental development, and construction of a DC-coupled precision analog fiber optic link. Topics to be covered include overall electrical and mechanical system parameters, basic circuit organization, modulation format, optical system design, optical receiver circuit analysis, and the experimental verification of the major design parameters.

  12. Research of data transmission security in videoconference system

    Institute of Scientific and Technical Information of China (English)

    LIU Yan-long; WANG Chun-lei; SUN Zhi-tao

    2007-01-01

    Many coal enterprises have built the videoconference systems on their LAN(Local Area Network). As the development of these enterprises, their organizations are distributed over our country and even over the world. Therefore, the videoconference systems have to run over WAN (Wide Area Network). Normally, the structure of a videoconference system is center_division including MCU (multi control unit) and participants. No QoS and security assurance are available now because all videoconference system is based on TCP/IP. Therefore, the system stability is absolutely depended on the Network.This paper discussed how to anti ARP attacking. The method discussed in this paper is based on TCP/IP.

  13. Nonlinear phase noise in coherent optical OFDM transmission systems.

    Science.gov (United States)

    Zhu, Xianming; Kumar, Shiva

    2010-03-29

    We derive an analytical formula to estimate the variance of nonlinear phase noise caused by the interaction of amplified spontaneous emission (ASE) noise with fiber nonlinearity such as self-phase modulation (SPM), cross-phase modulation (XPM), and four-wave mixing (FWM) in coherent orthogonal frequency division multiplexing (OFDM) systems. The analytical results agree very well with numerical simulations, enabling the study of the nonlinear penalties in long-haul coherent OFDM systems without extensive numerical simulation. Our results show that the nonlinear phase noise induced by FWM is significantly larger than that induced by SPM and XPM, which is in contrast to traditional WDM systems where ASE-FWM interaction is negligible in quasi-linear systems. We also found that fiber chromatic dispersion can reduce the nonlinear phase noise. The variance of the total phase noise increases linearly with the bit rate, and does not depend significantly on the number of subcarriers for systems with moderate fiber chromatic dispersion.

  14. The Development of a Smart Low-Cost AC Charging System*%一种低成本智能交流充电系统的研发*

    Institute of Scientific and Technical Information of China (English)

    具小平; 杨颋; 王波

    2013-01-01

      针对现有电动汽车交流充电桩存在的问题,并结合充电市场“点多、面广、投资少”的实际需求,提出了一种新型的电动汽车交流充电系统。讨论了该系统的结构、功能框图、充电付费流程和系统可靠性。与现有的充电桩相比,该系统具有成本低、占地面积小等特点,因而有广阔的应用前景。%Aiming at the problems of the existing AC charging pot for electric vehicles (EV), and in consideration of the actual AC charging market requirements of many sites, wide distribution and low cost, this paper proposes a smart low-cost AC charging system, and discusses its structure, function block diagram, charging payment process and system reliability. In comparison with the other kinds of existing AC charging pots, the proposed AC charging system has the advantages of low cost, small footprint and broad application prospect.

  15. Fatigue Prediction of a Gear Transmission System based on Vibro-Acoustic Measurements

    OpenAIRE

    Ahmaida, Anwar; Zhen, Dong; Gu, Fengshou.; Ball, Andrew

    2013-01-01

    Gearing components play a pivotal role in most power transmission mechanisms but their application in industry consistently results in significant disruption and losses due to gear failures. This emphasises the significance of condition monitoring and fault diagnostics techniques of gear transmission systems to enhance overall safety and operational reliability in order to minimise gearbox failure rates and their associated disruption and losses to industry. In a wide range of industrial cont...

  16. Transmission Modulated by Quantum Gate in Aharonov-Casher Ring

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    We study the electron transmission tuned by quantum gate in an Aharonov-Casher (AC) ring. Transmis-sion probability is obtained as a function of the normalized textured electric fields and Fermi energy. We find thatmodulating electron wavefunction in the stub can drastically affects electron transmission through the ring system.As Fermi energy crosses every eigenenergy of the isolated stub, the phases of both anomalous and periodic oscillationsof the AC conductance generally have abrupt change by π. On two sides of several special Fermi energies, bothanomalous and periodic oscillations have no abrupt phase change and are in phase. The detailed characteristics of theanomalous oscillations are dependent on the difference between the tilt angle of the spin and that of textured electricfield. By modulating external magnetic field applied to the stub, we present AC oscillations of spin-polarized conduc-tance within adiabatic limit.

  17. Reprint of “Performance analysis of a model-sized superconducting DC transmission system based VSC-HVDC transmission technologies using RTDS”

    Science.gov (United States)

    Dinh, Minh-Chau; Ju, Chang-Hyeon; Kim, Sung-Kyu; Kim, Jin-Geun; Park, Minwon; Yu, In-Keun

    2013-01-01

    The combination of a high temperature superconducting DC power cable and a voltage source converter based HVDC (VSC-HVDC) creates a new option for transmitting power with multiple collection and distribution points for long distance and bulk power transmissions. It offers some greater advantages compared with HVAC or conventional HVDC transmission systems, and it is well suited for the grid integration of renewable energy sources in existing distribution or transmission systems. For this reason, a superconducting DC transmission system based HVDC transmission technologies is planned to be set up in the Jeju power system, Korea. Before applying this system to a real power system on Jeju Island, system analysis should be performed through a real time test. In this paper, a model-sized superconducting VSC-HVDC system, which consists of a small model-sized VSC-HVDC connected to a 2 m YBCO HTS DC model cable, is implemented. The authors have performed the real-time simulation method that incorporates the model-sized superconducting VSC-HVDC system into the simulated Jeju power system using Real Time Digital Simulator (RTDS). The performance analysis of the superconducting VSC-HVDC systems has been verified by the proposed test platform and the results were discussed in detail.

  18. Bio-Authentication based Secure Transmission System using Steganography

    CERN Document Server

    Zehra, Najme; Ahuja, Somya; Bansal, Shubha

    2010-01-01

    Biometrics deals with identity verification of an individual by using certain physiological or behavioral features associated with a person. Biometric identification systems using fingerprints patterns are called AFIS (Automatic Fingerprint Identification System). In this paper a composite method for Fingerprint recognition is considered using a combination of Fast Fourier Transform (FFT) and Sobel Filters for improvement of a poor quality fingerprint image. Steganography hides messages inside other messages in such a way that an "adversary" would not even know a secret message were present. The objective of our paper is to make a bio-secure system. In this paper bio-authentication has been implemented in terms of finger print recognition and the second part of the paper is an interactive steganographic system hides the user's data by two options- creating a songs list or hiding the data in an image.

  19. Investigation of EDFA Performance in 8 Channel WDM Transmission System

    OpenAIRE

    Lavrinoviča, I; Poriņš, J

    2015-01-01

    Erbium Doped Fiber Amplifier (EDFA) obtained a wide range of applications in research and commercial applications in optical fiber communication systems. It has been considered as an attractive solution because of several major advantages - low loss optical window of silica based fiber (1525-1565 nm), high energy efficiency (>50 %) and time constant enough to cover modulation noises. However, the presence of amplified spontaneous emission (ASE), the difficulty in implementing a WDM system - t...

  20. Review of structural design trends for extra high voltage transmission systems

    Energy Technology Data Exchange (ETDEWEB)

    Cook, L.H.J.; Coblenz, J.

    1964-01-01

    Viewed on a national basis, the anticipated investment in ehv transmission systems for the next few years is a major consideration. A conservative review of Canadian transmission construction programs indicates that at least 7,000 miles of transmission in the voltage range of 360 kV to 735 kV, representing an investment of over one billion dollars, will be built within the next ten years and that this figure could be doubled if a start is made on a national grid. The various technologies associated with transmission line design and construction have undergone tremendous changes during the last decade. The careful integration of all these advances into the ehv lines now being planned is essential if any major reduction in transmission costs is to be achieved. It is hoped that a program of applied research into the structural elements of a transmission system will be initiated as quickly as possible in order that the benefits of such a program may be reflected in material reductons in the cost of the extra high voltage systems now being conceived across Canada.

  1. Analytical investigation of the pericyclic variable-speed transmission system for helicopter main-gearbox

    Science.gov (United States)

    Saribay, Zihni Burcay

    In the recent years, there has been significant interest in the new developments and improvements of the rotorcraft transmission systems. The main goal of the rotorcraft transmission research is the reduction of overall gear train weight while maintaining the efficiency and reliability. The Pericyclic Variable-Speed Transmission (PVT) System is one of the potential candidates of the future rotorcraft drive trains to achieve these goals. Hence, this thesis explores the feasibility of the Pericyclic Variable Speed Transmission (PVT) for rotorcraft transmissions. The contributions of this research are grouped in two main categories. These two categories are in the component level and in the system level. These contributions are originated from the analysis of the Pericyclic Variable Speed (PVT) System. In the component level, a new concept of face-gear meshing is presented first time in the gear research field. The meshing of a face-gear with another face-gear is presented at high shaft angles as an alternative to bevel gears. The conjugacy of this new face-gear meshing concept is formulated and demonstrated. The geometry, unloaded mesh kinematics and loaded mesh kinematics of the conjugate meshing face-gear pair is analyzed. The physics behind the meshing face-gear teeth contact is revealed using theory of gearing, differentiable geometry and elastohydrodynamic lubrication theory. The existence of the lubricant film formation between the meshing teeth is demonstrated. The behavior of the sliding friction coefficient is analytically simulated through the meshing cycle. In the system level contributions, the Pericyclic Variable Speed (PVT) Transmission is presented as a new unique innovative gear train mechanism. The speed change capability is analyzed for rotorcraft demands. The power flow behavior is explored for its use in variable speed transmission systems. The established component level contributions are evaluated with the PVT at the system level. The efficiency

  2. Observations of spatiotemporal instabilities in the strong-driving regime of an AC-driven nonlinear Schr\\"odinger system

    CERN Document Server

    Anderson, Miles; Coen, Stéphane; Erkintalo, Miro; Murdoch, Stuart G

    2016-01-01

    Localized dissipative structures (LDS) have been predicted to display a rich array of instabilities, yet systematic experimental studies have remained scarce. We have used a synchronously-driven optical fiber ring resonator to experimentally study LDS instabilities in the strong-driving regime of the AC-driven nonlinear Schr\\"odinger equation (also known as the Lugiato-Lefever model). Through continuous variation of a single control parameter, we have observed a string of theoretically predicted instability modes, including irregular oscillations and chaotic collapses. Beyond a critical point, we observe behaviour reminiscent of a phase transition: LDSs trigger localized domains of spatiotemporal chaos that invade the surrounding homogeneous state. Our findings directly confirm a number of theoretical predictions, and they highlight that complex LDS instabilities can play a role in experimental systems.

  3. Impact of Utility-Scale Distributed Wind on Transmission-Level System Operations

    Energy Technology Data Exchange (ETDEWEB)

    Brancucci Martinez-Anido, C.; Hodge, B. M.

    2014-09-01

    This report presents a new renewable integration study that aims to assess the potential for adding distributed wind to the current power system with minimal or no upgrades to the distribution or transmission electricity systems. It investigates the impacts of integrating large amounts of utility-scale distributed wind power on bulk system operations by performing a case study on the power system of the Independent System Operator-New England (ISO-NE).

  4. Max Launch Abort System (MLAS) Pad Abort Test Vehicle (PATV) II Attitude Control System (ACS) Integration and Pressurization Subsystem Dynamic Random Vibration Analysis

    Science.gov (United States)

    Ekrami, Yasamin; Cook, Joseph S.

    2011-01-01

    In order to mitigate catastrophic failures on future generation space vehicles, engineers at the National Aeronautics and Space Administration have begun to integrate a novel crew abort systems that could pull a crew module away in case of an emergency at the launch pad or during ascent. The Max Launch Abort System (MLAS) is a recent test vehicle that was designed as an alternative to the baseline Orion Launch Abort System (LAS) to demonstrate the performance of a "tower-less" LAS configuration under abort conditions. The MLAS II test vehicle will execute a propulsive coast stabilization maneuver during abort to control the vehicles trajectory and thrust. To accomplish this, the spacecraft will integrate an Attitude Control System (ACS) with eight hypergolic monomethyl hydrazine liquid propulsion engines that are capable of operating in a quick pulsing mode. Two main elements of the ACS include a propellant distribution subsystem and a pressurization subsystem to regulate the flow of pressurized gas to the propellant tanks and the engines. The CAD assembly of the Attitude Control System (ACS) was configured and integrated into the Launch Abort Vehicle (LAV) design. A dynamic random vibration analysis was conducted on the Main Propulsion System (MPS) helium pressurization panels to assess the response of the panel and its components under increased gravitational acceleration loads during flight. The results indicated that the panels fundamental and natural frequencies were farther from the maximum Acceleration Spectral Density (ASD) vibrations which were in the range of 150-300 Hz. These values will direct how the components will be packaged in the vehicle to reduce the effects high gravitational loads.

  5. 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...

  6. Investigate the Performance of LG 00 Mode in Cost Effective Hybrid Radio over Multimode Transmission System

    Directory of Open Access Journals (Sweden)

    Pardeep Kaur

    2014-05-01

    Full Text Available Radio over fiber (RoF technology composed for apprehension of future high performance integrated networks and future broadband networks. Multimode fiber links can offer a convenient approach for low cost and short Radio over Fiber (RoF systems. This work is based on the cost effective radio over multimode transmission system (Ro-MMF for long reach transmission. Error free transmission of 10 Gbps data with 10 GHz radio signal over multimode fiber link successfully demonstrated over 40 km. furthermore, The results are represented for Ro-MMF system by using LG (Laguerre-Gaussian 00 mode. The Performance of LG 00 mode in terms of SNR and Eye diagram investigated in proposed system.

  7. Harmonics in Offshore Wind Power Plants Employing Power Electronic Devices in the Transmission System

    DEFF Research Database (Denmark)

    Glasdam, Jakob Bærholm

    of wind power. The onshore as well as offshore wind power plants (OWPPs) therefore have to meet the same stringent requirement as the conventional power plants. This can be accommodated by employment of flexible alternating current transmission system (FACTS) devices, such as the static compensator...... gives rise to a number of challenges to the wind power industry with regard to construction, installation as well as transmission of the generated energy. The STATCOM and the voltage-sourced converter high-voltage direct current (VSC-HVDC) are attractive solutions for grid connection of remotely located...... OWPPs. The new system configuration requires in-depth knowledge of all relevant technical aspects, including e.g. the involved control systems performance and robustness for all possible operating conditions. The transmission system operator might impose new control requirements when the VSC...

  8. The Effects of Crack on the Transmission Matrix of Rotor Systems

    Directory of Open Access Journals (Sweden)

    Z.K. Peng

    2011-01-01

    Full Text Available The dynamic behavior of rotor containing crack is a subject of particular interest and has been extensively investigated by researchers. The effects of crack on the natural frequencies and modal shapes and motion orbits of rotor systems have already been well explored by researchers. In the present study, the infl uence of crack on the transmission matrices of the rotor systems is investigated by using the FEM (finite element method analysis and the HBM (harmonic balance method technique. It is for the first time revealed that there are differences between the transmission matrices for the fundamental frequency components and the transmission matrices for the super-harmonic components, and the differences are mainly determined by the crack location. The results are validated by numerical experiments where the system responses of a rotor system are obtained using Runge-Kutta method. The results are of significance for the development of effective crack detection methods in practice.

  9. Nonlinear phase noise mitigation in phase-sensitive amplified transmission systems.

    Science.gov (United States)

    Olsson, Samuel L I; Karlsson, Magnus; Andrekson, Peter A

    2015-05-04

    We investigate the impact of in-line amplifier noise in transmission systems amplified by two-mode phase-sensitive amplifiers (PSAs) and present the first experimental demonstration of nonlinear phase noise (NLPN) mitigation in a modulation format independent PSA-amplified transmission system. The NLPN mitigation capability is attributed to the correlated noise on the signal and idler waves at the input of the transmission span. We study a single-span system with noise loading in the transmitter but the results are expected to be applicable also in multi-span systems. The experimental investigation is supported by numerical simulations showing excellent agreement with the experiments. In addition to demonstrating NLPN mitigation we also present a record high sensitivity receiver, enabled by low-noise PSA-amplification, requiring only 4.1 photons per bit to obtain a bit error ratio (BER) of 1 × 10(-3) with 10 GBd quadrature phase-shift keying (QPSK) data.

  10. Transmission Congestion and Voltage Profile Management Using TCSC and TCPAR in Deregulated Power System

    Directory of Open Access Journals (Sweden)

    K.Ragini

    2014-10-01

    Full Text Available In present days all our basic needs are relates with electricity. As the population increases, the demand for electricity is also tremendously increases. In the past, the entire electricity industry is under the control of government and also monopolized. But now, the power industry in many countries is moving rapidly from regulated conventional setup to deregulated environment. The transmission congestion is one of the technical problems that particularly appear in the deregulated power system. If congestion is not managed we face the problems of electricity price improvement and security and stability problems. Congestion relief can be handled using FACTS device such as TCSC, TCPAR where transmission capability will be improved. These FACTS devices are optimally placed on transmission system using Sensitivity approach method. The proposed method is carried out on Modified IEEE-14 bus system and IEEE-24 bus system Using Power World Simulator17 software.

  11. Design of aircraft turbine fan drive gear transmission system

    Science.gov (United States)

    Dent, E.; Hirsch, R. A.; Peterson, V. W.

    1970-01-01

    The following basic types of gear reduction concepts were studied as being feasible power train systems for a low-bypass-ratio, single-spool, geared turbofan engine for general aircraft use: (1) single-stage external-internal reduction, (2) gears (offset shafting), (3) multiple compound idler gear system (concentric shafting), and (4) star gear planetary system with internal ring gear final output member (concentric shafting-counterrotation). In addition, studies were made of taking the accessories drive power off both the high-speed and low-speed shafting, using either face gears or spiral bevel gears. Both antifriction and sleeve-type bearings were considered for the external-internal and star-planet reduction concepts.

  12. 基于瞬时值解析的交流输电路径电气份额计算%Electrical Shares Calculation of AC Transmission Line Based on Instantaneous Value

    Institute of Scientific and Technical Information of China (English)

    于继来

    2014-01-01

    多个电气用户共用交流输电路径时,能否正确计算各自对输电路径的使用份额系数,关乎电力系统许多技术和经济问题的客观公正解决。然而,该问题目前尚未取得达成共识的解决方法。经重新审视发现,现有方法的研究思路普遍基于交流电路有关物理量的平均值、从相量分析的角度构造电气份额(electrical share,ES)计算关系,该思路可能从一开始就为方法存在理论缺陷埋下了隐患。文中回归到从交流电路瞬时值角度探讨问题的解决之道:先由交流电气用户和输电路径上的瞬时功率或瞬时电流的实际分布(包括方向和数值)情况,定义瞬时ES系数,再对瞬时ES系数求特定时间周期内的平均值。先求待研究物理量的瞬时值再求其平均值的计算方式,符合对任意连续时间过程相关物理量的一般评估思路。在此基础上,针对交流输电路径受端节点联接等效负荷用户(或送端节点联接等效电源用户)、送端节点联接电源和负荷用户、受端节点联接电源和负荷用户几种方式,给出了不同用户使用输电路径的瞬时ES系数和平均ES系数解析计算关系。理论检验和数值算例对比分析结果表明,源于瞬时值解析得出的ES系数计算方法,更具理论正确性,有可能尽早使问题取得共识性成果。%ABSTRACT:The correct calculation of multi-electrical-user’s share coefficients on the AC transmission line is about the objective and fair solutions for many power system’s technical and economic issues. However, the problem has not yet reached a consensus on computation method. This paper reviewed and found that the research ideas of the existed methods were generally based on the mean values of AC circuit physical quantities and established calculation formula of electrical shares from the phasor analysis. These ideas might store up method’s theoretical defect from

  13. Word width reduction system for videosignal processing and transmission

    NARCIS (Netherlands)

    Coenen, A.J.

    1991-01-01

    Abstract of WO 9104611 (A1) System for converting a PCM input signal with uniform noise spectrum, comprising a series of digital words each of K-bits appearing with a predetermined repetition frequency, into a PCM output signal with a non-uniform noise spectrum comprising a series of digital wor

  14. Phase-modulation transmission system for quantum cryptography.

    Science.gov (United States)

    Mérolla, J M; Mazurenko, Y; Goedgebuer, J P; Porte, H; Rhodes, W T

    1999-01-15

    We describe a new method for quantum key distribution that utilizes phase modulation of sidebands of modulation by use of integrated electro-optic modulators at the transmitting and receiving modules. The system is shown to produce constructive or destructive interference with unity visibility, which should allow quantum cryptography to be carried out with high flexibility by use of conventional devices.

  15. Experiment on 60-GHz MMW transmission performance in an optical fiber and wireless system

    Institute of Scientific and Technical Information of China (English)

    Qi Tang; Lin Chen; Jiangnan Xiao; Zizheng Cao

    2011-01-01

    We experimentally investigate the transmission performance of 60-GHz signals over standard single-mode fiber (SSMF) and wireless links at different bit rates.Experimental results show that in a transmission of over 10-km SSMF and 1.3-m wireless link, bit rate reaches up to 5 Gb/s and bit error rate (BER) is leas than 10-4.The main limiting factor in such radio-over-fiber (ROF) systems is intersymbol interferences caused by the so-called walk-off effect when BER is below 10-8.In addition, a transmission of over 20-km SSMF without chromatic dispersion compensation is briefly investigated.For a BER of 10-8, the optical penalty is 2 dB.%@@ We experimentally investigate the transmission performance of 60-GHz signals over standard single-mode fiber (SSMF) and wireless links at different bit rates.Experimental results show that in a transmission of over 10-km SSMF and 1.3-m wireless link, bit rate reaches up to 5 Gb/s and bit error rate (BER) is less than 10-4.The main limiting factor in such radio-over-fiber (ROF) systems is intersymbol interferences caused by the so-called walk-off effect when BER is below 10-8.In addition, a transmission of over 20-km SSMF without chromatic dispersion compensation is briefly investigated.For a BER of 10-s, the optical penalty is 2 dB.

  16. Absence of frequent herpesvirus transmission in a nonhuman primate predator-prey system in the wild.

    Science.gov (United States)

    Murthy, Sripriya; Couacy-Hymann, Emmanuel; Metzger, Sonja; Nowak, Kathrin; De Nys, Helene; Boesch, Christophe; Wittig, Roman; Jarvis, Michael A; Leendertz, Fabian H; Ehlers, Bernhard

    2013-10-01

    Emergence of viruses into the human population by transmission from nonhuman primates (NHPs) represents a serious potential threat to human health that is primarily associated with the increased bushmeat trade. Transmission of RNA viruses across primate species appears to be relatively frequent. In contrast, DNA viruses appear to be largely host specific, suggesting low transmission potential. Herein, we use a primate predator-prey system to study the risk of herpesvirus transmission between different primate species in the wild. The system was comprised of western chimpanzees (Pan troglodytes verus) and their primary (western red colobus, Piliocolobus badius badius) and secondary (black-and-white colobus, Colobus polykomos) prey monkey species. NHP species were frequently observed to be coinfected with multiple beta- and gammaherpesviruses (including new cytomegalo- and rhadinoviruses). However, despite frequent exposure of chimpanzees to blood, organs, and bones of their herpesvirus-infected monkey prey, there was no evidence for cross-species herpesvirus transmission. These findings suggest that interspecies transmission of NHP beta- and gammaherpesviruses is, at most, a rare event in the wild.

  17. Microcontroller - Based System for Electrogastrography Monitoring Through Wireless Transmission

    Science.gov (United States)

    Haddab, S.; Laghrouche, M.

    2009-01-01

    Electrogastrography (EGG) is a non-invasive method for recording the electrical activity of the stomach. This paper presents a system designed for monitoring the EGG physiological variables of a patient outside the hospital environment. The signal acquisition is achieved by means of an ambulatory system carried by the patient and connected to him through skin electrodes. The acquired signal is transmitted via the Bluetooth to a mobile phone where the data are stored into the memory and then transferred via the GSM network to the processing and diagnostic unit in the hospital. EGG is usually contaminated by artefacts and other signals, which are sometimes difficult to remove. We have used a neural network method for motion artefacts removal and biological signal separation.

  18. Frequency Transmission Control of Local Networked Control Systems Approach

    Directory of Open Access Journals (Sweden)

    O. Esquivel-Flores

    2012-08-01

    Full Text Available The use of Network Control Systems has been successful in the industry and therefore has opened several lines ofresearch. Control systems over a communication network include two important considerations, control andscheduling. Co-design strategies are focused on maintaining adequate control performance and maximize the level ofservice. Network scheduling is the main objective to resolve because through a balanced data load is possible tomaintain control performance in a desired level. This article reviews a scheduling strategy based on frequencytransition modeled as a linear subsystem, this control reconfigure on line the sensors’ periods. The case of study isthe control of a prototype helicopter and by numerical simulations it shows the effect of changing the transmissionfrequency.

  19. Grid connection of active stall wind farms using a VSC based DC transmission system

    DEFF Research Database (Denmark)

    Iov, Florin; Sorensen, Paul; Hansen, Anca-Daniela;

    2005-01-01

    are fulfilled. However, the traditional squirrel-cage generators based wind turbines/wind farms directly connected to the grid have less control capabilities. These wind turbines/farms cannot regulate their production and contribute to power system stability. A DC transmission system for connection...

  20. Cryogenic transmission electron microscopy (cryo-TEM) for studying the morphology of colloidal drug delivery systems

    DEFF Research Database (Denmark)

    Kuntsche, Judith; Horst, Jennifer C; Bunjes, Heike

    2011-01-01

    Cryogenic transmission electron microscopy (cryo-TEM) has evolved into an indispensable tool for the characterization of colloidal drug delivery systems. It can be applied to study the size, shape and internal structure of nanoparticulate carrier systems as well as the overall colloidal composition...