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IEEE Conference and Expo Transportation Electrification Asia-Pacific (ITEC Asia-Pacific)

作者： Yi Wang Jian-zheng Liu Xing-Tao Xu State Key Lab of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing Beijing CN Jiangsu Electric Power Company Research Institute Nanjing China

LCL filter can improve the output current of the shunt active power filter. The paper proposes a resonant LCL filter structure with a LC high-frequency filter branches adding to LCL filter with damping resistor. By LC resonance effect, the switching frequency harmonics are filtered more efficiently and the loss of the system is reduced. The paper also builds the system modeling and analyzes the stability of the grid filter with the deadbeat control, then gives parameter selection methods and simulates with PSCAD/EMTDC. All these are verified through the experiments on a 70-KW shunt APF prototype using deadbeat controller.

关键词： power harmonic filters Damping Active filters Harmonic analysis power filters Switching frequency Resonant frequency

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Analysis and simulation research on cascading trips of multiple wind farms

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Dianwang Jishu/power system Technology 2014年第6期38卷 1425-1431页

作者： Xu, Fengda Guo, Qinglai Sun, Hongbin Zhang, Boming Wang, Bin Li, Zhengshuo Ding, Tao Jia, Lin Xu, Xiaofei State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China North China Grid Company Limited Xuanwu District Beijing 100053 China

A simulation based analysis is proposed to find out the most relative factors during the cascading process, which is significant to support the future voltage control schemes for wind integration region. A hierarchical distributed simulation platform is built, which contains both the transmission and wind farms' distribution grid. In this way both the coupling among wind farms and the detailed characteristics of device level can be considered. By simulating shunt capacitors, wind turbine generators and static var compensators (SVCs) under different control mode, the different impact to cascading trips process are analyzed. With the simulation, it is found that centralized integrated wind farms are so closed-coupled that variations of active or reactive power in one wind farm would cause great changes of voltages in wind farms nearby. Researching results also indicate that coordination of various reactive power implements is essential to system voltage safety.

关键词： Wind farm

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Application of the complex algorithm in PMU-only state estimaiton

Application of the complex algorithm in PMU-only state estim...

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International Conference on power system Technology (powerCON)

作者： Yunfeng Cheng Chao Lu Kun Men Liang Tu the State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghual University Beijinz P.R. China the Academy of China Southern Power Grid Guangzhou P.R. China

China's electrical grid has installed more than 2500 sets of phasor measurement unit (PMU), covering almost all the 500 kV and above and part of the 220 kV substations, which in sure observable of the ultra-high voltage power network and provide mass data for system analysis. However, PMU measurements may contain bad data and the precision of measurements especially phase need to be further improved. state estimation is an effective method to deal with data contaminated by noise and bias. Therefore, it's of great significance to study the PMU-only state estimation (POSE) problem. The real number equations based on the rectangular coordinate system and weighted least squares (WLS)algorithm are the general method to solve the POSE problem at present, which need to convert phasors into their real and imaginary parts, thus enlarging the size of the coefficient matrix which decreases the computational efficiency. In this paper, complex number equations for the POSE problem are established and the complex number weighted least squares (CWLS) estimation model is built to solve the equation directly in the complex domain which needs no phasor converting. The error characteristics of PMU measurements in the complex domain are analyzed in depth which give a guidance of choosing weights and illustrate the robustness of the CWLS to phase. Test results demonstrate the contrast analysis between the CWLS and the WLS from the perspectives of estimation time, estimation accuracy and adaptability to different error levels, which shows that the performances of the CWL Sare better than the WLS. The robustness of the CWLS to phase is also showed in the tests.

关键词： Phasor measurement units Measurement errors Measurement uncertainty Phase measurement Current measurement Voltage measurement Equations

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Recent advances on smart grid technology and renewable energy integration

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Science China(Technological Sciences) 2013年第12期56卷 3040-3048页

作者： MEI ShengWei CHEN LaiJun State Key Lab of Control and Simulation of Power Systems and Generation Equipments (Dept. of Electrical Engineering Tsinghua University)

With the integration of renewable energy generations and other related changes,the smart grid,or the future electric power system,is confronted with new challenges and ***,it is a promising subject in electrical engineering and much work has been done on *** paper reviews the recent advances on the technologies of smart grid and renewable energy integration,from the aspects of modeling,simulation,protection and control,stability,operation,and planning.

关键词： smart grid renewable energy integration modeling simulation protection and control stability operation planning

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Expectative Modeling of Wide-area Damping Networked control systems with Long Stochastic Time Delay

Expectative Modeling of Wide-area Damping Networked Control ...

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第25届中国控制与决策会议

作者： Zhang Xinran Lu Chao Han Yingduo State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University

ISBN: (纸本)9781467355339

In this paper, the impact of stochastic time delay on wide-area damping networked control systems is analyzed. A disintegrate method of time-delay upon sampling period is approved. Furthermore, the expectative model of networked control systems with long and stochastic time delay, whose variance extent is larger than one sampling period, is theoretically proved and calculated. Finally, the effectiveness of this expectative model is confirmed on the simulation of a power system with 8 generators and 36 nodes.

关键词： Networked control system, Wide Area Damping control, Long Stochastic Time Delay, Expectative Model.

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Characteristics calculation and pattern recognition for partial discharge of cable joint

Characteristics calculation and pattern recognition for part...

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2014 International Conference on Communication Technology and Application(CTA2014)

作者： Y.F.Xia J.F.Gui X.Y.Chen S.Y.Gao J.H.Huang J.H.Lin Dongguan Power Breuse of Guangdong Grid School of Electrical Engineering Beijing Jiaotong University Department of Electrical Engineering Tsinghua University State Key Lab of Control and Simulation of Power Systems and Generation Equipments

ISBN: (纸本)9781845649302

For PD pattern recognition, six kinds of typical cable fault models are made and tested. Characteristics are calculated from test data. Multiple statistical characteristics of PD distribution map are calculated and pattern vectors are formed. Artificial neural network is trained for recognition. Through the selection and adjustment of characteristics and network parameters, recognition effect with satisfactory result is obtained.

关键词： cable joint partial discharge recognition

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Technology and Application of Online Partial Discharge Monitoring for power Equipments

Technology and Application of Online Partial Discharge Monit...

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The 5th International Conference on Reliability of Electrical Products and Electrical Contacts

作者： Shengyou GAO Junfeng GUI Dept.of Elec.Eng. Tsinghua UniversityState Key Lab of Control and Simulation of Power Systems and Generation Equipments School of Electrical Engineering Beijing Jiaotong University

Online partial discharge monitoring for power equipments is useful to improve the capacity of the power *** technology for PD testing is introduced in this *** and disadvantages of pulse current,UHF,ultrasonic and TEV method are present The status quo of online PD monitoring is analyzed,and the detection effect of online PD monitoring is not *** to improve the effect are *** include built-in sensors,increasing sensitivity and sample *** of the state quo indicates that the relevant technical standards and specifications must be revised to improve the normalization and standardization.

关键词： Online monitoring partial discharge(PD) pulse current UHF ultrasonic TEV

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Design optimization of ferrite rings for VFTO mitigation

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IEEE Transactions on power Delivery 2014年第99期PP卷 1-1页

作者： He, Jiaxi Guan, Yonggang Liu, Weidong Chen, Weijiang Li, Zhibing Department of Electrical Engineering State Key Lab of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing100084 China State Grid Corporation of China Beijing100031 China China Electric Power Research Institute Beijing100192 China

Very-fast transient overvoltage (VFTO)-related problems are raising growing concerns in China with the development of ultra-high voltage. The practice of fitting ferrite rings on gas-insulated switchgear busbars for VFTO mitigation has long been proposed but few investigations on its design optimization were conducted. Based on theoretical analysis of the simplified model, the optimal damping condition of ferrite rings is proposed, which is conducive to the type selection. The number of rings to be employed to ensure visible suppressing effects is given through simulations and the influence of the saturation is discussed. Impact on the power frequency is analyzed to be negligible. Finally, comparisons aremade between the theoretical conclusions and existing experiment results, which approve the optimal damping condition and agree with the number of rings to be employed. © 2014 IEEE.

关键词： Electric switchgear

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Discussion on tower shunt coefficient of UHV DC transmission line under lightning stroke

Discussion on tower shunt coefficient of UHV DC transmission...

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International Conference on Lightning Protection (ICLP)

作者： S Chen J Hu B Zhang Y Yin M Hua State Key Lab of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing China China Electric Power Research Institute Beijing China Tibet Electric Power Research Institute Lhasa China

ISBN: (纸本)9781479935451

The development of UHV transmission technology brings longer transmission distance, higher towers and more complicated terrain along the transmission lines, which make the shunt performance of transmission line under lightning stroke more diversiform compared to conventional ones. This paper discusses the effects of factors, such as lightning current waveform, footing resistance, transmission line span etc., on the shunt coefficient of UHV DC transmission lines, which is of great significance for setting out lightning-proof measures as well as the location of lightning stroke point. It is referred that lightning current waveform especially its front time as well as tower footing resistance plays a significant role in determine of the tower shunt coefficient under lightning stroke. As the results indicates, the shunt coefficient of ground wire gets larger as the footing resistance increases while it decreases first and then increases as the front time of the lightning current waveform increases. The shunt coefficient of tower is just the opposite.

关键词： EMTDC Educational institutions Poles and towers Wires Wide area networks Lightning

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Simplified mathematical model of inter-turn short circuit of field windings in hydro-generators and its application

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Science China(Technological Sciences) 2013年第4期56卷 898-909页

作者： HAO LiangLiang WU JunYong SUN YuGuang WANG XiangHeng School of Electrical Engineering Beijing Jiaotong University State Key Lab of Control and Simulation of Power Systems and Generation Equipment Tsinghua University

Inter-turn short circuit of field windings is a common electrical fault of *** is an important method of investigating the fault and providing data support for fault ***,huge numbers of pole pairs and damper loops in large hydro-generators would lead to lengthy calculation time,hindering scientific research and engineering *** deal with this problem,we analyze a theoretical basis for a damper winding simplified model and then propose an equivalent treatment *** the analysis of steady-state current harmonic characteristics of generators with different stator winding configurations during the fault,the simplified models suitable for steady-state calculation are derived from two aspects,namely,additional rotor harmonic current frequency characteristics and the relationship of the amplitude as well as the phase of each branch current of the *** calculation and experimental results of the two simplified models are then compared to verify the models' correctness.A calculation example of the Three Gorges left bank VGS generator shows few deviations between the calculation results of the simplified model and the original ***,the calculation time using the simplified model is 1/1500 that using the original model,which provides a more effective tool for on-line fault ***,the sensitivity-verification application of the fault-monitoring scheme based on the stator steady-state unbalanced current RMS is *** result shows that the scheme can monitor two-turn short circuits of field windings in the Three Gorges generator and provide high sensitivity.

关键词： hydro-generator field windings inter-turn short circuit simplified model on-line monitoring

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