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simulation of lightning strike in 2-D and 3-D with fractal theory and its application

Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2010年第22期30卷 127-134页

作者： Xu, Wei Chen, Shui-Ming He, Jin-Liang State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

Lighting causes great damage to power systems due to the stochastic nature of lightning discharges and the vulnerability of lightning leaders to various environments in the process of inception and propagation. In this work, the growth of diffusion limited aggregation (DLA) was adopted for reproducing branches and tortuosity of lightning channels in both 2-D and 3-D simulations. By comparing the fractal dimensions of natural lightning discharges and simulation results on various discharge settings, we discovered that a fractal coefficient η = 2 can deliver a credible model of lightning strikes. We further proved the consistency between simulation results and observations conducted in Japan during 2005 and 2006 winter seasons on lightning strikes to a windmill and its lightning-protection tower. But the credibility of the result needs to be verified by further experimental data, when the model extended from 2-D to 3-D. Moreover, striking probability and the shielding effect in the actual condition were analyzed with the proposed simulation model. © 2010 Chin. Soc. for Elec. Eng.

关键词： Fractal dimension

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The influence of wind on the audible noise of ultra HVDC transmission line in high altitude area

The influence of wind on the audible noise of ultra HVDC tra...

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Asia-Pacific Symposium on Electromagnetic Compatibility (APEMC)

作者： Min Li Rong Zeng Dawei Yang Zhanqing Yu Ruihai Li Lei Liu Bo Zhang Huaying Zhang State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China Technology Research Center China Southern Power Grid Company Limited China

ISBN: (纸本)9781424456215

The corona performance and the electromagnetic environment of the transmission system has become a crucial issue that has been taken into consideration in the line design, and among which audible noise (AN) is one of the most important factors. The wind in the high altitude area is mostly strong, and could greatly influence the AN. This paper, based on the high altitude HDVC test line, studied the characteristics of AN generated by the transmission line, and analyzed the influence of wind velocity and wind direction on the AN lateral profile.

关键词： Acoustic noise HVDC transmission Testing Wind speed Corona power transmission lines Microphone arrays Voltage Electromagnetic compatibility power engineering and energy

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Tests on electromagnetic environment of ultra HVDC transmission lines in high altitude region

Tests on electromagnetic environment of ultra HVDC transmiss...

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Asia-Pacific Symposium on Electromagnetic Compatibility (APEMC)

作者： Zhanqing Yu Rong Zeng Min Li Ruihai Li Lei Liu Bo Zhang Zheng Zhang Huaying Zhang State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China Technology Research Center China Southern Power Grid Company Limited China

ISBN: (纸本)9781424456215

The Ultra High Voltage DC power transmission technique is developed quickly in china but used barely in the world. Corona phenomenon in high altitude region is more serious, and corresponding electromagnetic environment is more severe as well. A UHVDC test lines are completed for tests in Kunming, china, with an altitude of 2100 m. An automotive electromagnetic environment testing system was installed under the line. Measurement of electromagnetic environment was carried out. Radio interference, audible noise, resultant electric field and ion current density at ground level were measured at different voltage from ±800kV to ±1000kV, and atmosphere conditions including sunny, rainy and cloudy weather. The measured result show some difference with those acquired at sea level and is significant for further studies of corona mechanism under high altitude condition. Measured results were compared with the calculated results.

关键词： HVDC transmission Atmospheric measurements Sea measurements Electromagnetic measurements Voltage Corona power transmission Automotive engineering System testing Electromagnetic interference

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Radio interference of Ultra HVDC transmission lines in high altitude region

Radio interference of Ultra HVDC transmission lines in high ...

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Asia-Pacific Symposium on Electromagnetic Compatibility (APEMC)

作者： Zhanqing Yu Rong Zeng Min Li Ruihai Li Lei Liu Dawei Yang Zheng Zhang Bo Zhang Feng Tian State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China Technology Research Center China Southern Power Grid Company Limited China

ISBN: (纸本)9781424456215

Corona phenomenon of Ultra High Voltage DC in high altitude region is more serious, and corresponding electromagnetic environment is more severe as well. Radio Interference is the most important consideration during the design and operation. Characteristics of RI and its influence factors were studied based on an UHVDC test line with an altitude of 2100 m in the National Engineering laboratory for UHV Technology, located in Kunming, china. The measuring system of RI long term tests was introduced. Lateral and longitudinal distribution and spectrum of RI near the transmission line were analysed at various voltages, weather conditions.

关键词： Electromagnetic interference HVDC transmission Voltage Corona Testing power transmission lines DC generators Conductors Transmission line measurements Electromagnetic compatibility

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Analysing on characteristics of lightning shielding failure of UHVAC double circuit transmission line based on leader progression method

Analysing on characteristics of lightning shielding failure ...

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Asia-Pacific Symposium on Electromagnetic Compatibility (APEMC)

作者： Zhiyong Wang Shaoan Wang Zhanqing Yu Yinan Geng Rong Zeng Jinliang He Zhizhao Li Guangzhou Power Supply Bureau China Southern Power Grid Company Limited Guangzhou China Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing China

ISBN: (纸本)9781424456215

Shielding failure of lightning is the key problem for safe operation of UHV transmission lines. Taking the feature of 1000KV AC double circuit transmission lines into account, the leader progression method with proper criterion was employed. The lightning shielding failure rate of top phase, middle phase and bottom phase of two different transmission line tower types were compute, in three different geography conditions. The research work is helpful for improving the lightning performance of UHV transmission lines.

关键词： Failure analysis Lightning Distributed parameter circuits Conductors power transmission lines Transmission line theory Voltage Corona Poles and towers power system simulation

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Dynamic emergency control in digital distribution substation with MW PV power

Dynamic emergency control in digital distribution substation...

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International Conference on Critical Infrastructures, CRIS

作者： Bin Wang Tianxiao Huang Xinzhou Dong Bo Jiang Z Q Bo State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China AREV A T & D UK Limited Stafford UK

MW level photovoltaic generation has enough power to support the partial loads in the island operations. But the challenge is how to balance the power supply and load while the power grid is blackout, and the power supply changes to PV power. In response to this question, the anti-islanding strategy is replaced by balancing the PV output and the load shedding in paper to achieve the available maximum power balance in distribution substation. It is achieved by collecting all feeders currents (power supply and feeder outputs), which is realized in the digital substation based on IEC61850. The system scheme and the dynamic emergency control strategy to inverters in PV controller are introduced in paper. The work of the paper is valued to the research on the novel dynamic control scheme in distribution system with DGs.

关键词： Electronic mail Medical services Electric shock

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Protection of microgrid

Protection of microgrid

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10th IET International Conference on Developments in power System Protection (DPSP 2010). Managing the Change

作者： Shenxing. Shi Bo. Jiang Xinzhou. Dong Zhiqian. Bo State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University China AREVA T and D Inc. Stafford UK

The paper analyses the existed protection of microgrid. And in order to meet the requirements of microgrid protection, a novel protection is presented in this paper. The protection based on local information without the need of communication, uses current traveling waves to identify faulted feeder, and the bus bar voltages to determine a event caused by fault or switch operation. In the protection scheme, current traveling waves are measured by current transducers in N line and phase lines, and wavelet multi-resolution analysis is used to decompose traveling wave signals. The initial traveling waves are compared in magnitude and polarity with each other to determine the faulted feeder. The protection is independent of microgrid operation connected with the main power grid or in island.

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A Pi-based control scheme for primary cascaded H-bridge rectifier in transformerless traction converters

A Pi-based control scheme for primary cascaded H-bridge rect...

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International Conference on Electrical Machines and systems (ICEMS)

作者： Tao Xinghua Li Yongdong Sun Min Department of Electrical Engineering Naval University of Engineering China State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University China

Cascaded H-Bridge rectifier (CHBR) is a more attractive solution in traction application for its transformerless structure. Because of the currents of different cells are exactly the same one, it is a challenge job to regulate the voltages of cells with only one current controller. In this paper, a PI-based control scheme is presented to deal with the voltages balance issue in CHBR. To satisfy the demand of rectifier such as unity power factor and regulated output DC voltages, the proposed control scheme consists of two parts. One is for shaping the grid current waveform and regulating the sum of DC-link voltages of all the cells; the other one is for balancing DC-link voltages. The latter is more concerned in this paper and is discussed in detail especially. simulations and experiments are carried on. The results verified the feasibility and effectiveness of the proposed scheme.

关键词： Rectifiers Voltage control Voltage measurement Converters Pulse width modulation Mathematical model

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state of the art of hybrid excitation permanent magnet synchronous machines

State of the art of hybrid excitation permanent magnet synch...

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作者： Wang, Shanming Xia, Yonghong Wang, Xiangheng Su, Pengsheng Huang, Shaogang Zhang, Anming State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China Department of Electrical and Automatic Engineering Nanchang University Nanchang Jiangxi 330031 China Military Deputy Department Dalian 426 Factory No.1 Yanhai Jie Xigang Qu Dalian Liaoning 116005 China

ISBN: (纸本)9788986510119

The hybrid excitation permanent magnet machine (HEPMM) combines two kinds of excitation: permanent magnet (PM) and electrical excitation, so it possesses the advantages of PM machines and overcomes the incapability of regulating the excitation field. By now many HEPMM schemes have been presented. In this paper the operation principle, structure, advantages and disadvantages of these HEPMMs have been reviewed and compared in detail. These HEPMMs are classified into three types by new classification method - placement of PM and iron poles. At last novel harmonic excitation HEPMM is proposed and discussed.

关键词： Permanent magnets

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state of the art of hybrid excitation permanent magnet synchronous machines

State of the art of hybrid excitation permanent magnet synch...

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2010 International Conference on Electrical Machines and systems, ICEMS2010

关键词： Iron Magnetic fields Windings Stator cores Rotors Stator windings Magnetic circuits

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