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11th IET International Conference on Developments in power systems Protection, DPSP 2012

作者： Wang, Bin Dong, Xinzhou Bo, Zhiqian State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China Alstom Grid Stafford ST17 4LX United Kingdom

ISBN: (纸本)9781849196208

Magnitude and duration of voltage sags are the most important two factors to the Lower Voltage Ride Through (LVRT) capacity of the wind generator. Since most voltage sags are caused by the system faults, and sag durations are controlled by the tripping time of overcurrent relay in power collection lines based on the sags' magnitude. The specification of the LVRT capacity of wind generator is introduced into the operation characteristics of the relay in power collection lines. The evaluation model of equivalent LVRT capacity to overcurrent protection is proposed in paper, and the equivalent LVRT capacities from zone I and zone II relay are quantified. Improvement measures are also proposed.

关键词： Overcurrent protection

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Study on Conducted Interference and Radiated Interference of Buck-Boost Converter in Electric Automobile

Study on Conducted Interference and Radiated Interference of...

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FISITA 2012 World Automotive Congress--Volume 6:Vehicle Electronics

作者： Jian Wang Youqun Zhao Liguo Zang Wei Wang College of Energy&Power Engineering Nanjing University of Aeronautics and Astronautics State Key Laboratory of Automotive Simulation and Control

Buck-boost converter is an important component of electric automobile,it is an important interference source in electric automobile,the study of the interference source is very important to restrain *** buck-boost converter in continuous conduction mode(CCM) is established by using circuit simulation software *** to the request of GB18655-2002,the simulation study on common-mode conducted interference,differential-mode conducted interference and far-field radiated interference of buck-boost converter are *** commonmode current radiation of buck-boost converter is simplified as an electric dipole radiation mode and the differential-mode current radiation is simplified as a rectangular loop *** order to improve the electromagnetic compatibility of buckboost converter in electric automobile,some measures to reduce the conducted interference and the radiated interference are proposed.

关键词： Buck-boost converter Conducted interference Radiated interference PSPICE Electric automobile

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Positive-sequence component based three-phase unbalanced power flow solution for distribution system with PV nodes

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2012年第1期32卷 115-121页

作者： Li, Hongwei Sun, Hongbin Zhang, An'an Liu, Qingyou State Key Laboratory of Oil and Gas Reservoirs Geology and Exploitation Southwest Petroleum University Chengdu 610500 Sichuan Province China State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

The traditional power flow methods aren't appropriate to the electrical distribution systems with distributed generators (DG). Therefore, a direct unbalanced three-phase power flow algorithm was presented in this paper. The proposed approach which was developed based on the path matrix, utilized the special topological structure of distribution systems and established the incident matrix of node voltages and injection currents. Based on the assumption that the positive-sequence voltage magnitudes of PV nodes are invariable, the relation of reactive power and compensation voltage for the PV nodes had been derived by the positivesequence component and path matrix. As a result, a new approach handling PV nodes of DG had been proposed and could be integrated into the proposed power flow method. It needn't introduce any additional active power at PV nodes and kept the positive-sequence voltage magnitudes on their scheduled values, considering that reactive power limits were not violated. The results of the 6-bus and the 69-bus test systems verified the validity and universality of the proposed methods. © 2012 Chin. Soc. for Elec. Eng.

关键词： Reactive power

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Optimal allocation of distributed generators in a distribution network using adaptive multi-objective particle swarm optimization

Optimal allocation of distributed generators in a distributi...

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2011 International Conference on Electrical, Information Engineering and Mechatronics, EIEM 2011

作者： Cheng, Shan Chen, Min-You Fleming, Peter J. Li, Xia State Key Laboratory of Power Transmission Equipment and System Security and New Technology School of Electrical Engineering Chongqing University Chongqing China Department of Automatic Control and Systems Engineering University of Sheffield Sheffield United Kingdom

ISBN: (纸本)9781447124665

This study presents the optimal allocation of distributed generators (DGs) in distribution network based on an adaptive multi-objective particle swarm optimization (AMPSO). In order to enable the DGs to make the best contribution to the distribution network, a multi-objective optimization model addressing power loss and a voltage stability index (VSI) is constructed, in which the capacity factor of DGs is taken into consideration. In the AMPSO, some adaptive techniques including the use of dynamically changing inertia weight, time-varying acceleration coefficients, mutation operation and circular crowding sorting have been integrated to improve the convergence and the diversity performance of the algorithm. The proposed algorithm has been used to determine the optimal allocation of DGs in a IEEE 33-bus distribution network. simulation results show that the proposed method can identify the optimal solutions with a good tradeoff between the power loss and the VSI. © 2012 Springer-Verlag London Limited.

关键词： Multiobjective optimization

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X-ray backlighting of wire expansion and plasma merging of z-pinch load with 10-40kA/wire

X-ray backlighting of wire expansion and plasma merging of z...

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IEEE International Conference on Plasma Science (ICOPS)

作者： Xinlei Zhu Xiaobing Zou Ran Zhang Shen Zhao Haiyun Luo Xinxin Wang Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

It is well known that the evolution of wire array z-pinch load can be divided into several phases: wire explosion, inter-wire plasma merging, implosion and stagnation. In this paper, experiments with x-pinch backlighter to study the initial wire explosion and inter-wire plasma merging were performed on the pulsed power generator PPG-I at Tsinghua University. An x-pinch (13-25μm Mo and 5-18μm Wu wires) used as soft x-ray source was installed in the centre between the output main electrodes of PPG-I generator, and the object z-pinch load was installed in one of the return current posts. The object z-pinch load consists of 2-4 tungsten wires of 5-18 μm diameter, 12 mm long, and 2 mm spacing between wires. The evolution images of wire explosion and inter-wire plasma merging were recorded with high resolution x-ray film, which was covered with a mass step-wedge filter to calibrate the mass density distribution of wire explosion and inter-wire merging plasma. Based on extensive discharge tests, the time sequence of backlighting images of z-pinches was obtained. In the paper, we also discussed how to determine the interface between high-density wire core and low-density surrounding plasma, and then presented the expansion rates of high density wire core and the mass density distribution of inter-wire plasma under different z-pinch current.

关键词： Wires Plasmas Merging Explosions Educational institutions Generators Radio access networks

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EQUIVALENT CAPACITY OF THE LOWER VOLTAGE RIDE THROUGH FOR WIND FARM FROM OVERCURRENT PROTECTION IN power COLLECTION LINES

EQUIVALENT CAPACITY OF THE LOWER VOLTAGE RIDE THROUGH FOR WI...

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IET International Conference on Developments in power System Protection

作者： Bin Wang Xinzhou Dong Zhiqian Bo State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Alstom Grid

ISBN: (纸本)9781622761050

关键词： Wind Farm Lower Voltage Ride Through Overcurrent Protection power collection lines

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Application and benefit analysis of substation state estimation

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Dianli Xitong Baohu yu Kongzhi/power System Protection and control 2012年第12期40卷 56-61页

作者： Li, Qing-Xin Wang, De-Xing Sun, Hong-Bin Wu, Wen-Chuan Wang, Jing Guo, Qing-Lai Zhang, Bo-Ming State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Beijing 100084 China East China Electric Power Dispatch and Control Sub-Center East China Grid Company Limited Shanghai 200002 China

A substation three-phase nonlinear state estimation method based on zero impedance branches helps to identify topology and analogy errors at substation level and accordingly enhances the control center's state estimation reliability and accuracy. Some issues during the practical implementation process of the technology are reported, such as the hardware configuration, measurement integration, the communication between substation and control center, time setting and period selection. The benefits of the proposed technology have also been analyzed. It is shown that this technology has high reliability and low burden on communication, and improves the ability of monitoring of power grids and the reliability of the real-time power network model significantly. The proposed technology is verified effective by both simulation experiments and field-site applications in East China power Grid, and is well qualified for real-time online applications, which has broad popularization and application prospects.

关键词： state estimation

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Design and implementation of photovoltaic lighting system with high luminous efficacy LEDs

Design and implementation of photovoltaic lighting system wi...

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International Conference on power Electronics and Motion control (IPEMC)

作者： Liqiang Yuan Zhiping Chen Xianlai Hu Junjie Ge Zhengming Zhao State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9781457720857

With the background park lighting application, and based on the characteristics of advanced devices in the system, this paper studies the photovoltaic (PV) light emitted diode (LED) lighting system in three main aspects, which are the design of the whole system, hybrid control strategy combining the maximum power point tracing (MPPT, for PV panels) with the energy management(for battery), and LED driving and dimming. Taking the example of an actual 50W high luminous efficacy LED system, the design, implantation and experiments are described in detail. In addition, the long-term measurement results in real environment are illustrated in this paper.

关键词： Batteries LED lamps Switches Pulse width modulation Discharges (electric)

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A novel hybrid-clamped four-level converter

A novel hybrid-clamped four-level converter

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Annual IEEE Conference on Applied power Electronics Conference and Exposition (APEC)

作者： Kui Wang Yongdong Li Zedong Zheng Lie Xu State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China

A novel hybrid-clamped four-level inverter topology is proposed in this paper. Only two active switches and a floating capacitor are required as clamping devices per phase leg. The DC-link of this topology is subdivided into three parts and the voltage balancing of DC-link capacitors and floating capacitors can be achieved by selecting proper redundant switching states. The operating principle and voltage balancing method of this converter are introduced in details. simulation and experimental results are presented to confirm the validity of this topology.

关键词： Capacitors Switches Voltage control Topology Clamps Integrated circuit modeling Electric potential

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Application of Fuzzy-Rough Set theory and improved SMO algorithm in aircraft engine vibration fault diagnosis

Application of Fuzzy-Rough Set theory and improved SMO algor...

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Prognostics and System Health Management Conference (PHM)

作者： Hongzhi Xu Dongxiang Jiang Lei Liang State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Thermal Engineering Tsinghua University Beijing China

ISBN: (纸本)9781457719097

Aircraft engine is an important component of the airplane, which lifespan and reliability have directly influence to flight safety. Vibration analysis is an effective fault diagnosis method for airplane's mechanical construction fault. Several typical vibration faults have drawn from the vibration analysis on the basis of fault mechanism in aircraft engine, and the standard vibration fault-symptom (Fuzzy Membership) relationship table have constructed based on Fuzzy Mathematic theory in this paper. Sample data are simulated on the basis of this table. Sequential Minimal Optimization (SMO) is a fast algorithm for training Support Vector Machines (SVM). The simulated result showed a great improvement on computation efficiency by selecting double threshold parameter for SMO algorithm than single threshold. In order to examine the algorithm's effect applying in the aircraft engine fault diagnosis, Radial Basis Function (RBF) Neural Network, C4.5 Decision Tree, SVM (chunking), Platt's SMO and Improved SMO algorithm are applied to the training data and test data. It is shown that the Improved SMO algorithm displayed superior comprehensive performance. Finally, the vibration fault feature is reduced based on Fuzzy-Rough Sets theory. The research shows that the Improved SMO algorithm is quicker than other algorithm in aircraft engine fault diagnosis with the reduced feature attributes, and its accuracy is high.

关键词： Vibrations Accuracy Safety Aircraft Classification algorithms Support vector machines

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