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

作者： Xudong Wang Zhengming Zhao Guanhua Chen Fanbo He State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing P. R. China

A broadband RF energy harvesting system over a frequency range of 900MHz-3GHz has been designed and tested. Some detailed issues of RF design have been studied and tested to improve the efficiency of the rectifier. Test results show that as low as -20dBm RF power can be harvested by this system. The series and parallel connections of two RF energy harvesting systems have also been studied, compared with the single system.

关键词： Radio frequency Broadband antennas Rectifiers Energy harvesting Broadband communication Antenna measurements

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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, CTA 2014

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

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. © 2014 WIT Press.

关键词： Partial discharges

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Travelling wave based single phase grounding protection for distribution system

Travelling wave based single phase grounding protection for ...

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12th IET International Conference on Developments in power system Protection, DPSP 2014

作者： Dong, Xinzhou Wang, Jun Shi, Shenxing Wang, Bin Dominik, Bak Kirby, Brian Yang, Xia State Key Lab of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 10084 China Alstom Grid Stafford ST174LX United Kingdom

ISBN: (纸本)9781849198349

It is very difficult to correctly identify single-phase-to-ground fault (SFG) in distribution system with neutral non-effectively grounded (NNG). A novel travelling wave based singlephase-to-ground protection is proposed in the paper. The polarity of initial transient current and voltage travelling waves are used to identify the fault direction, and power frequency voltages are used to distinguish SFG from phaseto- phase fault to ensure the reliability of the protection. In the paper, wavelet transforms and module maxima theory was adopted to represent the polarity of travelling waves effectively and construct protection algorithm,. The analysis and simulation demonstrate that the protection is valid.

关键词： Wavelet transforms

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Research on HVIGBT transient mixture model and parameter extraction method

Research on HVIGBT transient mixture model and parameter ext...

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

作者： Gaohui Feng Zhengming Zhao Liqiang Yuan Shiqi Ji Jincheng Zhao Mechanical Engineering College Shijiazhuang China State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

This paper presents a kind of HVIGBT transient mixture model and corresponding parameter extraction method. The HVIGBT model can divide into MOSFET and BJT two parts. The two models are formed respectively according to HVIGBT work principle, in addition, the carrier transport equations have been simplified for avoiding Kirk effect in BJT model. The transient model is realized in PSIM software in the paper. Extraction methods, which include estimation by empirical values, calculation by testing waveforms and comparison with same type models, are adopted in extracting model parameters. Through comparing testing and simulation waveforms, the model's simulation accuracy is proved.

关键词： Mathematical model Testing Semiconductor device modeling Transient analysis Insulated gate bipolar transistors Integrated circuit modeling Capacitance

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Design of grounding system for wind-photovoltaic-energy storage Hybrid power station 4

Design of grounding system for wind-photovoltaic-energy stor...

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2014 4th International Conference on High Voltage Engineering and Application, ICHVE 2014

作者： Lin, Cheng Sen, Wang Zhizhong, Li Jing, Wang Bo, Zhang Weidong, Shi Power Grid Grounding Engineering Laboratory of State Grid Corporation of China Xi'an Shaanxi710049 China State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing100084 China China Electric Power Research Institute Beijing100192 China

ISBN: (纸本)9781479966134

Based on the Chinese demonstration project of Zhangbei wind-photovoltaic-energy storage (W-PV-ES) hybrid generation, which is the world's biggest and Chinese first new energy utilization platform, the design of grounding system for W-PV-ES Hybrid power station was studied in this paper. Firstly according to the soil resistivity of that power station, measured by the Wenner four-electrode method, the soil constitution, that is three-level layer in summer and is four-level layer including an 1.5m high and 2000·m permafrost in winter, was got, and grounding grid models of W-PV-ES hybrid generation was studied. Then grounding system of that W-PV-ES station was designed, that was the single wind turbine uses concentric bicyclic earth electrode, whose radius are 7m and 10m, and the PV-ES power station uses one horizontal earth electrode every 10m in one direction, every 50m in another direction, and there are 2.5m long vertical grounding rods every 10m around the PV-ES station. For the substation, we adopt the horizontal grounding grid with a 10m interval between conductors and 0.8m burial depth. On the condition that earth current is 10KA, the earth's surface potential, contact potential, and step potential were simulated. After that safety of 35kV system and secondary system were analyzed, when there was short trouble. Finally influence on earth resistance by different grounding materials was studied, galvanized flat steel and copper material was presented as two kinds of selection schemes of grounding materials for considering economic considerations. © 2014 IEEE.

关键词： Energy storage

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Summary of health index theory and application of state maintenance equipment 5

Summary of health index theory and application of state main...

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5th International Conference on Reliability of Electrical Products and Electrical Contacts, ICREPEC 2014

作者： Cheng, Lin Manjun, L.I.U. Peng, Feijin Dept. of Elec. Eng. Tsinghua University State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Beijing100084 China Guangdong Power Grid Company Foshan Power Supply Bureau Foshan528010 China

ISBN: (纸本)9789881532329

This paper describes several methods for condition-based maintenance, introduced CBM, RCM development process, the main theoretical logic, techniques and practices. Focuses on the health index based on equipment maintenance strategies, namely CBRM. Focused on the development of narrative context, theoretical foundation, model healthy index. And for its application in power transformers were introduced.

关键词： Condition based maintenance

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An adaptive wind power smoothing method with energy storage system

An adaptive wind power smoothing method with energy storage ...

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IEEE General Meeting power& Energy Society

作者： Hanchen Xu Can Wang Chao Lu Zhigang Lu State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China Electric Power Research Institute of China Southern Power Grid Guangzhou China

The random and intermittent nature of wind power (WP) makes the integration of large-scale wind farms into power system problematic. The energy storage system (ESS) is an effective means to smooth the WP. This paper presents a novel Kalman filter (KF) based adaptive wind power smoothing method to determine the power output of an ESS. ESS capacity can be significantly reduced by adjusting the parameters of KF adaptively according to the WP fluctuation. Meanwhile, a fuzzy logic controller is introduced to manage the remained energy level (REL) of the ESS. By considering the current WP fluctuation, the REL and the power output of the ESS together in the controller, the REL can be successfully managed to a reasonable range without deteriorating the WP fluctuation. A test case based on data from an actual wind farm validated the effectiveness of the proposed method.

关键词： Fluctuations Wind power generation Energy storage Wind farms Kalman filters Fuzzy logic Smoothing methods

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Phase-Shift control of Isolated Bidirectional DC-DC Converters for Unidirectional power Flow

Phase-Shift Control of Isolated Bidirectional DC-DC Converte...

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IEEE Energy Conversion Congress and Exposition

作者： Junjie Ge Zhengming Zhao Junchao Ma Fanbo He Liqiang Yuan Ting Lu State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University 100084 Beijing P. R. China

ISBN: (纸本)9781479957774

In the conventional phase-shift control of isolated bidirectional DC-DC converters, the phenomenon of power backflow is quite obvious. General improved phase-shift control methods can reduce the power backflow of the input. However, they do not take the power backflow of the output into consideration. In this paper, a novel phase-shift control of isolated bidirectional DC-DC converters for unidirectional power flow is proposed. It can eliminate the power backflows of both the input and the output at the same time. Furthermore, the converters in the proposed phase-shift control can achieve the zero-current switching in the whole power rang. Experimental results from a prototype verify the feasibility and validity of the proposed control method, and show superior performance.

关键词： DC-DC power converters Voltage control Load flow control systems Educational institutions Prototypes

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Technology and application of online partial discharge monitoring for power equipments 5

Technology and application of online partial discharge monit...

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5th International Conference on Reliability of Electrical Products and Electrical Contacts, ICREPEC 2014

作者： Gao, Shengyou Gui, Junfeng Dept. of Elec. Eng. Tsinghua University State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Beijing100084 China School of Electrical Engineering Beijing Jiaotong University Beijing100044 China

ISBN: (纸本)9789881532329

Online partial discharge monitoring for power equipments is useful to improve the capacity of the power supply. Main technology for PD testing is introduced in this paper. Advantages 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 good. Opinions to improve the effect are given. They include built-in sensors, increasing sensitivity and sample rate. Analysis of the state quo indicates that the relevant technical standards and specifications must be revised to improve the normalization and standardization.

关键词： Partial discharges

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Automatic discovery method of power system critical flowgates considering multiple security themes in power grid

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Dianwang Jishu/power system Technology 2014年第5期38卷 1169-1174页

作者： Zhao, Feng Sun, Hongbin Tan, Yan Guo, Qinglai Guo, Wenxin State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China Guangdong Electric Power Control Center Guangzhou 510600 Guangdong Province China

Based on summarizing the features of selecting critical flowgates in actual power grid, an automatic discovery method of power system critical flowgates considering multiple security themes in power grid is proposed. Based on topological structure of power grid and online power flow, the electric partitioning of power grid is performed and different types of critical flowgates are selected according to different security theme: according to the demand on transient security theme the long-distance transmission channel composed by tie line between electric partitionings is chosen as critical flowgate;according to the demand on thermal stability theme, the transmission channel composed of high voltage transmission lines with high transmission capacity, which interact each other obviously, is chosen as critical flowgate;according to the thermal stability at load side the transmission channel composed of low voltage transmission lines with higher transmission capacity, which interact each other obviously, is chosen as critical flowgate. Taking Guangdong power Grid in China as testing example, test results show that the proposed method considers common security themes in power grid accurately and different kinds of critical flowgates can be attained;the obtained critical flowgates not only conform to a posteriori critical flowgate given by experts in the field of power grid operation, and new critical flowgates can be discovered, besides, the discovery results are reasonable and creditable.

关键词： Thermodynamic stability

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