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Analysis of Nonlinear Torsional dynamics Using Second-Order Solutions

IEEE Transactions on power systems 2010年第1期25卷 423-432页

作者： Wuhui Chen Tianshu Bi Qixun Yang Jixiang Deng Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control Ministry of Education North China Electric Power University Beijing China Northeast Dianli University Jilin China

Based on the modal series method, this paper derives the second- and first-order solutions of torques for investigating nonlinear torsional dynamics. The derivatives of the two types of solutions are compared to explain the advantage of the second-order solutions. The index is given for evaluating the feasibility of solutions. Subsequently, several nonlinearity indices are defined to quantify the effects of nonlinear modal interactions on torsional dynamics, and the suitable indices are determined for analyzing nonlinear torsional dynamics. The systematic method is developed for the analysis of nonlinear torsional dynamics. Furthermore, the concept of nonlinear modal interactions is extended to deal with both the fundamental and the combination modes; the nonlinearity contribution factors are emphasized. The study is implemented on two modified cases from the IEEE first benchmark model, which validates the presented method for investigating torsional dynamics in the stressed case and gives new engineering insights into nonlinear torsional dynamics.

关键词： Nonlinear dynamical systems power system dynamics power system transients Modal analysis Torque Bismuth Resonance Steady-state Electromagnetic transients Electromagnetic analysis

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Multi-level voltage quality adjustment device based on FPGA control

Multi-level voltage quality adjustment device based on FPGA ...

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IEEE Conference on Industrial Electronics and Applications (ICIEA)

作者： Hong Qiu Zhongdong Yin Chengxin Dai Yajing Di North China Electric Power University Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control of Ministry of Education Beijing China

This paper studies the FPGA-based control 4 H-bridge cascaded 9-level structure of voltage quality adjustment device, for the variety of voltage quality issues appears in electric power system, providing a comprehensive solution. With the voltage swell, voltage sag, voltage harmonics, voltage fluctuations which occurs in the power system, it can give out the complex compensation, so as to ensure the system voltage quality, 0.1MVA/400V Low-voltage prototype was designed and developed for validating the variety of experiments. Experimental results show that the design of this device is feasibility and effectiveness.

关键词： Field programmable gate arrays Voltage control Voltage fluctuations power quality power system harmonics Circuit topology Control systems Prototypes Inverters Circuit testing

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Research on soft regulation strategy of VSC-HVDC systems

Research on soft regulation strategy of VSC-HVDC systems

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IEEE General Meeting power& Energy Society

作者： Song Wang Gengyin Li Ming Zhou Zhe Zhang Laboratory of Power System Protection and Dynamic Security Monitoring and Control under Ministry of Education North China Electric Power University Beijing China

ISBN: (纸本)9781424465491

Based on power electronic converting current devices which can be controlled quickly, VSC-HVDC system can regulate active power, reactive power, DC voltage, and line voltage flexibly. Different regulation strategies have different influences on the power system stability. A worse regulation strategiy may lead to sharp fluctuation of electrical measurements and longer regulation time, which is harmful for the system stability. It is worse when faults happen during the regulation. The traditional regulation strategy is that the reference value of regulation is set to the goal value directly, sometimes the change is very serious like the reversal of power flow, and the electrical measurements may have sharp fluctuation during the regulation. Different from the traditional regulation strategy, a new regulation strategy, called soft regulation strategy, was presented in the paper, which can minish the fluctuation of electrical measurements and shorten the regulation time. The soft regulation strategy is helpful for the system stability and the device security. The soft protection strategy for serious impact from AC faults is also presented, by which the fault terminal is softly closed and the non-fault terminal works right as before, while the DC voltage can be kept, which increases the efficiency of VSC-HVDC system and makes preparation for restoration. Simulations performed in PSCAD/EMTDC verify the proposed regulation strategy.

关键词： Circuit faults Voltage control power conversion Reactive power Electric variables measurement Fluctuations

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A novel method for determining minimum break point set based on network reduction and relays incidence matrix

A novel method for determining minimum break point set based...

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International Conference on Critical Infrastructures, CRIS

作者： Donghua Ye Jing Ma Zengping Wang Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control Ministry of Education North China Electric Power University Beijing China

This paper presents a simple and effective approach based on two dynamic matrixes of node-relay matrix (NRM) and relay-incidence matrix (RIM) to determine minimum break point set (MBPS) for coordination of the directional relays. Firstly, the NRM and RIM are defined and their calculation methods are developed. Then, some optimization operations for network reduction and special structure are presented to update the NRM and RIM and the detailed flowchart is provided. At last, case studies on various topologies demonstrate the effectiveness and simplicity of the proposed method.

关键词： power system dynamics Phantoms Network topology Protective relaying Heuristic algorithms

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A combined prediction method of wind farm power

A combined prediction method of wind farm power

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International Conference on Critical Infrastructures, CRIS

作者： Chen Ye Gengyin Li Ming Zhou Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control Ministry of Education North China Electric Power University Beijing China

ISBN: (纸本)9781424480807

Wind power forecasting has great significance to the connection of wind farms to the electric power system. This paper analyzes individual forecast models, such as the time series forecasting, Elman network forecasting that based on the chaos theory, grey neural network forecasting, and generalized regression neural network forecasting, etc., then puts forward an entropy weight combination prediction model, and an optimal combination forecasting model for the wind power forecasting that based on vector angle cosine. The forecasting results indicate that due to the different forecast precisions of different methods, the methods with high precisions may bring great variation in some points, and the combination forecast can reduce the forecasting variation in several points, which improve the forecasting precision.

关键词： Forecasting Predictive models Wind forecasting Wind power generation Artificial neural networks Entropy Wind farms

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Study on Characteristics of Multi-Phase Rectifier system Based on Phase-Shifting Reactor

Study on Characteristics of Multi-Phase Rectifier System Bas...

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

作者： Ning Kong Zhongdong Yin Ruochen Cui Po Yang Zhijian Wang Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control of Ministry of Education (North China Electric Power University) Beijing China

In view of the harmonic problems caused by plenty of nonlinear load, especially large-capacity rectifiers, are becoming more and more serious, a kind of harmonic suppression method based on phase-shifting reactor (PSR) is studied in this paper. The problem of determination of the winding turns aiming at a certain phase-shifting angle is solved through theory analysis and calculation. And the topological structure of multi-phase rectifier system composed by cascade phase-shifting reactors is introduced. Also, a method of determining the phase-shifting angles is proposed and the characteristic harmonic of rectifier system is suppressed comprehensively. At last, simulation and experiment of twelve-phase rectifier system composed by phase-shifting reactors are made and the results show that using phase-shifting reactors can realize the same effect as phase-shifting transformers. The harmonic caused by rectifier system can be suppressed very well by phase-shifting reactors.

关键词： Rectifiers Inductors power system harmonics Iron Transformers Laboratories Harmonics suppression Voltage Electrical equipment industry power system protection

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The theoretical analysis and compensating experiment of voltage fluctuation

The theoretical analysis and compensating experiment of volt...

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IEEE Conference on Industrial Electronics and Applications (ICIEA)

作者： Chengxin Dai Zhongdong Yin Qiu Hong Shuhong Kong Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control of Ministry of Education North China Electric Power University Beijing China

This paper researches the intrinsic relationship between inter-harmonics and typical voltage fluctuations of which the enveloping line is sine wave, it analyses the effects to voltage fluctuations of inter-harmonics of different frequencies, including a single inter-harmonic and a pair of inter-harmonics. In this paper, experiments of voltage fluctuations production and compensation are all carried out. The disturbance producing device makes use of different frequency voltage to modulate inverter output voltage, then the output voltage is superimposed on system voltage, at last voltage fluctuation waveforms of different frequency are produced, the voltage compensation device firstly detect the output voltage of disturbance producing device, and the standard reference 220V is subtracted from it, the result is used to modulate the output voltage of the compensation device, and it get a good compensation effect.

关键词： Voltage fluctuations power system harmonics power systems Inverters Frequency conversion Furnaces Harmonic analysis Information analysis Signal analysis Laboratories

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A Novel Method of Substation Configuration Based on the Virtual Impedance

A Novel Method of Substation Configuration Based on the Virt...

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

作者： Jinfang Zhang Zengping Wang Yagang Zhang Jing Ma Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control of Ministry of Education North China Electric Power University Beijing China

Substation configuration is a vital part of the power system network topology, and its implementation has taken most of the total time of network topology analysis. The improvement of the network topology efficiency focuses on the faster and more accurate substation configuration based on the distributed modeling formation, which can be finished in parallel way in order to reduce the time consumed. Based on the analysis of the common characteristic of adjacent matrix and node admittance matrix and impedance matrix, a new method of original and tracking topology analysis in the substation has been proposed in this paper, which uses the addition of the virtual switch impedances and the virtual ground branches. The directional treatment to the original adjacent matrix is avoided in this new method. According to the characteristic of node impedance matrix, the work for substation configuration has been realized. Finally, the examples have validated the function of the new method in analyzing the original topology and tracking the variation in switch status. Compared to other methods based on adjacent matrix, this method features the easy-to-program property.

关键词： Substations Impedance Network topology Switches Circuit topology power system analysis computing Circuit breakers power system protection power system dynamics power system security

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Simulation and Test Study on Module Based Controllable Shunt Reactor

Simulation and Test Study on Module Based Controllable Shunt...

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

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

This paper puts forward a TCR module based new type shunt high voltage reactor, which consists many small capacity thyristor controlled reactor modules and via three-windings transformer connecting to system. The secondary windings of transformer adopt duplex winding structure and each has multi-bank TCR modules being in delta connection. In this topology, the harmonic current injected into the power system is limited remarkably. A 500 kvar/10 kV industrial prototype was developed, and digital simulation based on EMTDC/PSCAD and field test were carried out to verify the characteristics of topology proposed.

关键词： Testing Shunt (electrical) Inductors Topology power system harmonics PSCAD Thyristors Voltage control Control systems Joining processes

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Calculation and analysis of capacity credit of wind farms based on Monte-Carlo simulation

Calculation and analysis of capacity credit of wind farms ba...

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IEEE General Meeting power& Energy Society

作者： Shuo Zhang 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 China

How to compare the wind power generation and traditional power generation in aspect of capacity is essential of power system expansion. The capacity credit is a convenient and effective way to compare these two different types of power generation. Unfortunately, the definition of capacity credit of wind farms is not clear and generally acknowledged. In this paper, a more clear definition of wind farms' capacity credit based on well-known concept of effective load carrying capability (ELCC) is presented. As well as a calculation method of wind farms' capacity credit based on non-sequential Monte-Carlo simulation, this method considered the failure of transmission lines. The secant method is used at capacity credit calculation process, and the modified direct current optimal power flow method is adopted in power flow calculation. Several different influence factors of capacity credit of wind farms such as the cut-in, cut-out and rated wind speed and the rated capacity of the wind turbine generator, transmission capacity of transmission lines and different integration solutions are analyzed in IEEE-RTS79 case studies.

关键词： Wind farms Reliability power system reliability power generation power transmission lines Monte Carlo methods

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