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International Conference on High Voltage Engineering and Application, ICHVE

作者： Jianbiao Li Peizhuan Huang Jia Tan Dan Ma Yizhi Fang Wenxia Sima Ming Yang Daixiao Peng Zhuhai Power Supply Bureau China Southern Power Grid Zhuhai China State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing China

ISBN: (纸本)9781509004973

Ferroresonance is a complex phenomenon in power systems for its very complicated behavior. This paper proposes a new method for ferroresonance behavior analysis using it steady state peak voltage value distribution on a three-dimensional space, by which the peak voltage behavior can be clearly detected with the change of the system parameters. Then, a new pulse suppression strategy for ferroresonance is also proposed. Pulse width modulation and proportional-integral (PI) control methods are used in the strategy. Simulation study shows that the fundamental, sub-harmonic and chaotic ferroresonance can all be suppressed by the pulse suppression strategy easily.

关键词： Ferroresonance Voltage control power systems Steady-state Damping Transient analysis Logic gates

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Ferroresonance overvoltage features extraction using nonlinear analytical technique

Ferroresonance overvoltage features extraction using nonline...

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International Conference on High Voltage Engineering and Application, ICHVE

作者： Jianbiao Li Tingxi Sun Jia Tan Dan Ma Yizhi Fang Sima Wenxia Ming Yang Daixiao Peng Zhuhai Power Supply Bureau China Southern Power Grid Zhuhai China State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing China

ISBN: (纸本)9781509004973

Ferroresonance is complicated phenomenon for its various modes. In this paper, two nonlinear features are extracted based on nonlinear analytical Technique. The features can be used to analyze the motion characteristics of the ferroresonance system of the overvoltage time series. The study on overvoltage acquired from a power substation shows that the feature is very useful for ferroresonance mode identification, especially for the quasi-periodical ferroresonance and chaotic ferroresonance.

关键词： Ferroresonance Time series analysis Feature extraction Voltage control Maximum likelihood estimation Trajectory Delay effects

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Study on the Influence of Secondary Load to the Error Characteristics of CVT

Study on the Influence of Secondary Load to the Error Charac...

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International Conference on High Voltage Engineering and Application

作者： Kun Liu Ruihan Wang Xiang Zhang Wei Jiang Yongsen Li Weigen Chen State Grid Sichuan Electric Power Corporation Metering Center Chengdu 610045 China State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing 400044 China

ISBN: (纸本)9781509004973

With the advantage of high dielectric strength and low cost, capacitive voltage transformers (CVTs) have been applied to measure the voltage in power grid widely. Recently, CVTs own the problem of big error, insulation performance degradation and high failure rate due to the complicated environment. Secondary load is an important factor to impact CVT's accuracy by analysis. Consequently, we established a simplified analysis model of CVT to research the influence mechanism of secondary load and a test platform of 220kV CVT to research its error characteristic with different load capacity and power factors. The experimental results showed secondary load capacity and power factors should be kept in a reasonable range. Moreover, it should be paid particular attention to the light load, no load and the situation when the power factor was less than 0.8, because the CVT of which faced the risk of exceeding error.

关键词： Capacitive Voltage Transformer Secondary load Error characteristics Accuracy

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Research on the double-crystal temperature compensation of an optical sensor for the non-contact measurement of over voltage

Research on the double-crystal temperature compensation of a...

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International Conference on High Voltage Engineering and Application, ICHVE

作者： Tianhua Xian Feng Zheng Shicai Lu Lei Zhang Jian Yang Tong Liu Rui Han Tianshengqiao Branch China Southern Power Grid Xingyi China State Key Laboratory of Power Transmission Equipment& System Security and New Technology Chongqing University Chongqing China

ISBN: (纸本)9781509004973

For two types of non-contact over voltage sensors, environment temperature is one of the essential parameters to cause the phase difference. In this paper, mechanism analysis of electro-optic modulation is finished and experiment is designed according to the equations from the mechanism analysis. Exploration is done on the temperature compensation method for electro-optical sensors in non-contact voltage sensor, and researches for temperature characteristics of two types of untouched voltage sensors are conducted, with the comparison for the theoretical calculation results and practical results, reasons are analysed and cautions are listed in practical engineering application.

关键词： Temperature sensors Sensor phenomena and characterization Temperature Crystals Voltage control Electrooptic effects

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A novel application of BP neural networks to evaluate the safety of power grid in wildfire disasters

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International Journal of Simulation: Systems, Science and technology 2016年第27期17卷 32.1-32.5页

作者： Wu, Chuangping Zhong, Yashan Liu, Hongfei Wang, Yan Niu, Dongxiao Gao, Fuqiang School of Civil Engineering Luoyang Institute of Science and Technology LuoyangHenan471023 China State Key Laboratory of Disaster Prevention & Reduction for Power Grid Transmission and Distribution Equipment ChangshaHunan China

Increasing national demands for electric energy have meant the continuous operation of transmission power lines at high capacity and across-regions. Numerous risk factors impact transmission lines resulting in increasing frequency of fire in hot weather and threatening the security and stability of the grid. This paper picks 10 indices from three aspects of meteorological factors, environmental factors and line factors to build a comprehensive evaluation model of grid wildfire disaster using the BP neural network. By training and testing with Matlab, it shows that both training error and testing error are small. The model is vital in studies to assess the risks in the continuous use of high capacity power lines. © 2017, UK Simulation Society. All rights reserved.

关键词： Neural networks

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Electric field disturbance caused by an unmanned aerial vehicle flying near the HV power transmission line

Electric field disturbance caused by an unmanned aerial vehi...

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International Conference on High Voltage Engineering and Application, ICHVE

作者： Shemin Liu Congbing Sheng Fanzhong Meng Shengdan Wang Rui Wang Yabo Zhang Yunfeng Zhu Zheng Xu Wei He Puyang Power Supply Bureau Henan Power Grid Co. Ltd China State Key Laboratory of Power Transmission Equipment and System Security and New Technology Chongqing University Chongqing China

ISBN: (纸本)9781509004973

Unmanned aerial vehicle (UAV) has been used by the electric utility in many situations such as the power transmission line inspection. When the UAV flying close to the high voltage (HV) power transmission line, there are risks of flashover through the UAV or corona discharge on the UAV because of the electric field disturbance caused by the UAV. To estimate the safe distance between the UAV and transmission lines or insulators, a simulation model had been built by the Finite Element Method (FEM) which including the UAV and a standard 220kV power transmission line. By analyzing the electric field distributions caused by the distance between the UAV and transmission lines, the relation between the distance R from UAV to transmission line and the maximum electric field strength on the UAV was obtained. The FEM simulation results reveal that the electric discharging will not happen when the distance between the UAV and transmission line is not less than 0.1 m, and a smooth structure of UAV will be better.

关键词： Unmanned aerial vehicles Electric fields power transmission lines Poles and towers Insulators Inspection Finite element analysis

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Lightning performance of EHV and UHV overhead transmission Lines in China southern power grid

Lightning performance of EHV and UHV overhead transmission L...

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International Conference on Lightning Protection (ICLP)

作者： Hansheng Cai Lei Jia Gang Liu Shangmao Hu Jian Shi Hengxin He Xiangen Zhao Junjia He China Southern Power Grid Electric Power Research Institute Guangzhou China State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

ISBN: (纸本)9781509048434

Lightning stroke is the main cause of trip-outs of EHV and UHV transmission lines in China Southern power grid (CSG). In order to improving the lightning performance of overhead transmission lines, the lightning activities of CSG in 2006 to 2014 was analyzed. It indicates that the coastal Guangdong and Guangxi province are suffered more ground flashes, where the average ground flash density is over 7.98 flashes/km 2 /year. 306 lightning flashover incidents of 500kV AC, ± 500kV HVDC and ± 800kV UHVDC transmission lines were investigated. It is inferred that about 84% lightning flashover incidents was caused by lightning shielding failure. The corresponding ground wire protection angle for 81% incidents is larger than 5°, and with protection angle decreases, lightning trip-out failures are significantly reduced. Based on the guidelines proposed by IEEE and CIGRE working group, CSG has developed their own lightning risk estimation tool named LPTL. The predication result of six 500kV AC transmission lines was compared to field experience which validates the IEEE recommended method for 500kV AC transmission lines. Further works should be done to revisit the validity of existing risk estimation method for HVDC transmission lines.

关键词： Estimation Lightning protection power transmission lines power grids Flashover Decision support systems

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Research and Application of a Non-contact Optical Voltage Sensor for the Monitoring of Lightning and Switching Overvoltage in EHV power grid

Research and Application of a Non-contact Optical Voltage Se...

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International Conference on Lightning Protection

作者： Rui Han Qing Yang Wenxia Sima Shangpeng Sun Tong Liu Hongwen Liu Ke Wang Yunnan Power Grid co. LTD Electric Power Research Institute Kunming China State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing China

ISBN: (纸本)9781509048434

In this paper, a type of sensor for the non-contact monitoring of lightning and switching overvoltage in power grid is presented. It is designed based on Pockels effect and stray-capacity coupling theory. Double-crystal structure is utilized to restrain the unwanted influence caused by natural birefringence. The transmission of the data is achieved by optical fibers which are immune to the electromagnetic interference in substation. This type of sensor is applied to an EHV transformer substation for on-line monitoring.

关键词： Lightning overvoltage Pockels effect Non-contact monitoring Double-crystal LiNbO_3

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The study on sympathetic inrush current of converter transformers in HVDC system and its identification method

The study on sympathetic inrush current of converter transfo...

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12th IET International Conference on AC and DC power transmission (ACDC 2016)

作者： Kanjun Zhang Xuanwei Qi Shiyun Zhang Wenbin Cao Fan Yang Xianggen Yin State Grid Hubei Electric Power Research Institute Wuhan China 430077 State Key Laboratory of Advanced Electromagnetic Engineering and Technology (Huazhong University of Science & Technology) Wuhan China 430074

ISBN: (纸本)9781510832657

This paper analyses the mechanism of the sympathetic inrush current of the converter transformer of the HVDC transmission system. The impacting factors of the sympathetic inrush current, including the system impedance, the closing angle and the initial remnant flux of the incoming transformer, and the operating condition of the HVDC system and so on, are analysed utilizing on the PSCAD/EMTDC soft. Based on this, this paper proposed two identification methods for the sympathetic inrush current and the simulation proofs the validity of these methods.

关键词： identification method HVDC sympathetic inrush current converter transformer

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Reliability evaluation of grid-connected micro-grid considering demand response

Reliability evaluation of grid-connected micro-grid consider...

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International Conference on Probabilistic Methods Applied to power Systems (PMAPS)

作者： Ping Zhou Ziyuan Chen Hongqin Yang Lili Wen Yin Liu Bo Hu Yinghao Ma Yun Xia Ruosong Xiao Bo Li State Grid Chongqing Economic Research Institute Chongqing University Chongqing Sichuan CN State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing China

ISBN: (纸本)9781509019717

The switching in of renewable resources to micro-grids and the implementation of demand response strategy has made reliability evaluation of micro-grid become increasingly complex. This paper focuses on the influence of demand response strategy on micro-grid's reliability. The coordination degree between the micro-grid's new energies and loads can influence micro-grid's reliability and the utilization rate of new resources. Concerning this problem, a load demand response model based on the degree to which the micro-grid's new energies satisfy the load is built. The index of the satisfaction degree is defined. Based on the time period effect of the photovoltaic generating set's contribution and the TOU electricity price strategy, a load demand response model to achieve the maximum satisfaction degree is set up, and is solved by the PSO algorithm. According to the rectified load curve and considering the micro-grid's structure as well as the energy-storage equipment's contribution strategy, a method to evaluate reliability of the grid-connected micro-grid considering demand response is established. The results of the calculation example indicate that the proposed load demand response strategy based on the degree to which the micro-grid's new energies satisfy the load can efficiently improve the reliability of micro-grid.

关键词： Load management Reliability Decision support systems Indexes Load modeling Linear programming

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