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2009 International Conference on Industrial and Information systems, IIS 2009

作者： Wang, Fei Zhang, Chengcheng Mi, Zengqiang Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control under Ministry of Education North China Electric Power University Baoding 071003 Hebei Province China Foreign Language Teaching and Researching Department Hebei University Baoding 071000 Hebei Province China

ISBN: (纸本)9780769536187

Anti-islanding method with reliable protection and reasonable control run an important role in grid connected PV power generation system. The detection and calculation of real and reactive power are the bases of many inverter resident passive and active islanding detection method (IDM). As well as the detection and calculation of real and reactive power also concern with the inverter control of grid connected PV power generation system. In this paper, considering instantaneous voltage and instantaneous current are periodic function about time, think of it in terms of periodic function space to define the inner product and norm, Hilbert space based power theory is proposed. Real power, reactive power and apparent power in Hilbert space based theory are defined. This proposed Hilbert space based power theory provide a novel view for the protection, islanding detection and control of grid connected PV power generation system. © 2009 IEEE.

关键词： Electric power system control

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A novel algorithm of calculating the circulating current on the delta side of three phase wye-delta connected transformer

A novel algorithm of calculating the circulating current on ...

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IEEE/PES Transmission and Distribution Conference and Exhibition: Asia and Pacific

作者： Tao Zheng Qiang Liu Department of Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control China Electric Power University Beijing China

ISBN: (纸本)9781424452293

The circulating current on the delta side of wye-delta connected three-phase power transformer is hard to measure. The differential transformer protection has to adopt current phase compensation method to compensate the circulating current. However, the differential current hardly reflect the magnetic exciting current of transformer no matter what kind of current phase compensation methods used. It limits many algorithms of identifying inrush current, such as the promising one based on the equivalent instantaneous inductance. How to obtain the circulating currents in delta side has become a difficult problem in transformer protection. In this paper, based on the voltage equations of transformer, the calculation of the resistance and leakage inductance of winding is deduced. And then, a novel algorithm of calculating the circulating currents in delta side is proposed Simulation results of MATLAB verify the accuracy of this algorithm, which offers a new way to calculate the differential currents exactly.

关键词： power transformers Phase transformers Inductance Surge protection Equations Current measurement Asia power measurement Phase measurement MATLAB

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The finite elements analysis on magnetic field of controllable saturated reactor

The finite elements analysis on magnetic field of controllab...

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International Conference on power Electronics and Drive systems (PEDS)

作者： Wang Ziqiang Yin Zhongdong Yang Po Li Ke key Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control of Ministry of Education North China Electric Power University Beijing China Laboratory of Power System Protection and Dynamic Security Monitoring and Control of Ministry of Education North China Electric Power University Beijing China

In the power system, the controllable reactor can be used as reactive power compensation device to limit over-voltage operation, reduce no-load or light load loss and improve transmission capacity. It is with characters of simple structure, easy maintaining, low cost and high stability, etc. The magnetic field is closely related to the reactor performance. In this paper, aiming at a controllable saturated reactor prototype, using the finite elements method, the magnetic field is studied. Then, the precise 2-D prototype field-circuit coupling model is established based on the magnetic field analysis and the finite element analysis software - ANSYS. Using this model, the magnetic field and working currents concrete values under the condition that AC and DC excitations co-exist within the core are calculated. The analysis results indicate that finite element analysis theory can effectively analyze the magnetic field of the reactor.

关键词： Finite element methods Magnetic analysis Magnetic fields Inductors power system stability Software prototyping power system analysis computing Lighting control power system control control systems

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A Novel MPPT control Algorithm Based on Numerical Calculation for PV Generation systems

A Novel MPPT Control Algorithm Based on Numerical Calculatio...

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第六届IEEE国际电力电子与运动控制会议 (2009 IEEE 6th International power Electronics and Motion control Conference-ECCE Asia

作者： Jing Hu Jiancheng Zhang Hongbo Wu Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control (North China Electric Power University) Baoding071003 China

In the future solar energy will be very important energy source. It is noticeable that the output characteristics of a PV array are influenced by the environment factors, and the conversion efficiency of PV arrays is very low. Therefore a Maximum power Point Tracking (MPPT) technique is needed to draw peak power from the solar array in order to maximize the produced energy. This paper introduces a novel MPPT control algorithm for photovoltaic (PV) power generation systems. The proposed algorithm based on numerical calculation is able to perform MPPT with only one step by quadratic interpolation. And a constant voltage tracking (CVT) startup is used in the MPPT method to enhance the accuracy and the speediness. The rationality and the feasibility of the algorithm developed in this paper are verified by building simulation model using MATLAB SIMULINK tool. The results indicate that the proposed approach can effectively improve the MPPT speed and accuracy simultaneously.

关键词： control systems Solar power generation Photovoltaic systems Voltage power generation Solar energy Atmospheric modeling Mathematical model Costs Temperature

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Research on a Novel Series-Connected Voltage Fluctuation Generator

Research on a Novel Series-Connected Voltage Fluctuation Gen...

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International Conference on Energy and Environment Technology (ICEET)

作者： Renzhong Shan Zhongdong Yin Xiangning Xiao Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control of Ministry of Education North China Electric Power University China

A novel voltage fluctuation and flicker generating main circuit topology is proposed in this paper, combined with passive and active to realize voltage fluctuation and flicker. The fundamental frequency power is supplied by system source and the other frequency fluctuation power is supplied by active components, so the capacitor of generator is easy to realize larger because of lower active loss. Full-bridge diode rectifier is adopted to maintain the stable DC-bus voltage, the later inverter is controlled by instantaneous value voltage and current double closed-loop to make sure good static and dynamic performance. The inverter output two frequency voltage waveforms, and added to fundamental frequency sinusoidal voltage waveform by transformer so that the typical sinusoidal modulation voltage fluctuation and flicker waveform is obtained. The simulation model is set up on the platform of Matlab/Simulink. Finally, the simulation and experimental results show that the proposed main circuit and control strategy is feasible and efficient.

关键词： Voltage fluctuations Frequency power supplies Inverters Circuit simulation Circuit topology Capacitors power generation Diodes Rectifiers

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Available Transfer Capability Evaluation Based on Sensitivity Analysis

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IFAC Proceedings Volumes 2009年第9期42卷 62-67页

作者： Yajing Gao Gengyin Li Ming Zhou Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control under Ministry of Education North China Electric Power University Beijing 102206 P.R. China Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control under Ministry of Education North China Electric Power University Beijing 102206 P.R. China (Tel: +86 10 80798551)

According to the definition of Available Transfer Capability by North America Electric Reliability Council (NERC), we know that ATC not only depends on the topology of power network but also on the parameters of components. So a series of adequacy indices are proposed to evaluate ATC. Through thorough analyses on these indices, the sensitivities of components parameters to these adequacy indices are deduced. The impact of components parameters’ small variations on ATC can be reflected by these sensitivities, the importance degree of each component can be embodied. Furthermore, by sensitivity analysis we can effectively identify ATC bottlenecks and get important guide information for operation and planning. The algorithm based on MATLAB 6.5 is developed. The correctness and effectiveness of the proposed sensitivity analysis method are verified using IEEE-RTS79 test system.

关键词： Available Transfer Capability adequacy indices sensitivity analysis

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Enhancement voltage stability of wind farm access to power grid by novel SVC

Enhancement voltage stability of wind farm access to power g...

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IEEE Conference on Industrial Electronics and Applications (ICIEA)

作者： Junjie Zhang Zhongdong Yin Xiangning Xiao Yajing Di Key Laboratory of Power System Protection and Dynamic Monitoring and Control under Ministry of Education North China Electric Power University Beijing China

ISBN: (纸本)9781424427994

This paper studies the voltage stability problems of wind farm access to electric grid. Based on the equivalent circuit of asynchronous machine, it deduces the relationship of wind turbine angular velocity rotation with the induction generator terminal voltage. Aiming at wind power for 10 kV distribution grid, a novel SVC is proposed to replace the fixed capacitors compensating devices. The reactive power can be detected based on the instantaneous reactive power theory and with this method the reactive power compensation is fast and continuous. The voltage level of wind farm access system is stable with a voltage feedback control strategy. The new SVC winding structure can achieve a multi-pulse, injecting the system small harmonic current component. Research results show that a corresponding control strategy of the novel SVC compensation device can be very good to improve voltage stability of wind farm access to the grid.

关键词： Voltage power system stability Wind farms power grids Static VAr compensators Reactive power Circuit stability Equivalent circuits Wind turbines Angular velocity

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A New dynamic Voltage-Var Compensator Based on SVPWM

A New Dynamic Voltage-Var Compensator Based on SVPWM

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International Conference on Energy and Environment Technology (ICEET)

作者： Tao Huang Zhongdong Yin Renzhong Shan Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control of Ministry of Education North China Electric Power University Beijing China

In this paper, a new dynamic voltage-var compensator is introduced, compared to the traditional SVC, the new voltage source of continuous two-way adjustable SVC has significant advantages. This paper has introduced the fundamental of the SVPWM; SVPWM control technology is an optimized PWM control technology, compared with the traditional PWM technology, SVPWM with a high utilizationrate, less harmonic control simple, easy-to-digital realization of the advantages. The simulink is used to simulation and analysis. The simulation results show this SVC has its own advantage. It can regulate the voltage smoothly and continually.

关键词： Space vector pulse width modulation Switches Voltage control Reactive power control Static VAr compensators Reactive power power system harmonics Pulse width modulation inverters Inductors Capacitors

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Multi objectives operation of cascade inverter-based voltage quality compensator with PWM rectifier supply

Multi objectives operation of cascade inverter-based voltage...

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International Conference on power Electronics and Drive systems (PEDS)

作者： Renzhong Shan Zhongdong Yin Xiangning Xiao Yajing Di Ke Li Key Laboratory of Power System Protection and Dynamic Monitoring and Control under Ministry of Education North China Electric Power University Beijing China

A novel main circuit topology of voltage quality compensator (VQC) is proposed in this paper, composed of PWM rectifier and cascade H-bridges inverter. The three phase inverter is decoupling controlled. PWM rectifier is adopted to maintain the dc-bus voltage stably and provide or absorb real power. The inverter is controlled by carrier phase shifting with FPGA. The simulation model is set up on the platform of PSCAD/EMTDC, the voltage sag, swell and harmonic compensation is researched by theoretical and simulation. Finally, the simulation results show that the proposed main circuit topology and control strategy is feasible and efficient for multi objectives voltage quality compensation.

关键词： Pulse width modulation inverters Rectifiers Circuit simulation Circuit topology Pulse width modulation Voltage fluctuations Field programmable gate arrays PSCAD EMTDC Voltage control

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Characteristic Analysis of UHV Secondary Arc Current under Different power Transmission

Characteristic Analysis of UHV Secondary Arc Current under D...

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IEEE PES Asia-Pacific power and Energy Engineering Conference (APPEEC)

作者： Lixia Zhou Huiyuan Zhang Jun Wen Xiangning Xiao Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control of Ministry of Education North China Electric Power University Beijing China

Along with the enhancement of voltage level, harmful affect of the secondary arc current to the system becomes more and more serious. The transmission power of the lines is one of factors that influence the secondary arc current obviously. The voltage distribution along the transmission line will changes according to the different transmission power, which will lead to the variation of the induction component from the sound phases when the fault occurs. In this paper, the quadric-mode transformation is adopted to establish the mathematic model of secondary arc current in the double-circuit transmission line. According to the variation of power transmission, the secondary arc current of different fault point is calculated. The results indicate that secondary arc current is influenced much by the line transmission power, and the variation trend changes along with the fault point. When the fault occurs in head or terminal of the line, the secondary arc current may becomes larger along with the increasing of the transmission power, thus effective suppress measurements must be taken.

关键词： power transmission Voltage power transmission lines Mathematical model Poles and towers Capacitors Electromagnetic coupling Laboratories power system protection power system dynamics

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