EFT/B引起的变压器中性点过电压识别方法  

Recognition Method of Transformer Neutral Point Overvoltage Caused by EFT/B

作　　者：黄睿[1,2] 李兴源[1] 朱晓楠[3] 廖建权 王强钢 周念成[4] HUANG Rui;LI Xing-yuan;ZHU Xiao-nan;LIAO Jian-quan;WANG Qiang-gang;ZHOU Nian-cheng(School of Electrical Engineering Information,Sichuan University,Chengdu 610065;Sichuan Electric Power Commissioning Test Institute,Chengdu 610020;College of Electrical and Information Engineering,Hunan University,Changsha 410082;State Key Laboratory of Power Transmission Equipment&System Security and New Technology(Chongqing University),Shapingba Chongqing 400044)

机构地区：[1]四川大学电气信息学院,成都610065 [2]四川省电力工业调整试验所,成都610020 [3]湖南大学电气与信息工程学院,长沙410082 [4]输配电装备及系统安全与新技术国家重点实验室(重庆大学),重庆沙坪坝区400044

出　　处：《电子科技大学学报》2019年第5期728-733,共6页Journal of University of Electronic Science and Technology of China

基　　金：国家电网公司科技项目(522830140003)

摘　　要：电快速瞬变脉冲群(EFT/B)会使变压器中性点产生暂态过电压,使继电保护发生误动作。针对EFT/B引起变压器中性点间隙保护在线路分闸时会引发连锁误动的现象,研究了其对变压器中性点过电压的影响。在分析断路器场路关系的基础上,得到了一种确定交流电弧熄灭与重燃时刻的方法。对断路器在不同时刻开断、开断不同短路类型故障和不同开断速度等因素对变压器中性点过电压的影响规律开展了深入研究,结果表明:断路器以约1.4m/s的速度在电压幅值时刻开断三相短路故障的情况下,变压器中性点产生的EFT/B过电压最为严重。针对EFT/B、雷电和单相接地3种故障引起的变压器中性点过电压的特性分析,利用小波包变换策略得到3种过电压的时频特性和能量分布特性,定义高低频能量比值作为判别依据,仿真实验结果表明该判据能够准确地对这3种过电压做出判别。该文研究旨在为变压器中性点防护提供参考。The research on the influence factors and recognition of electrical fast transient burst (EFT/B) is of great significance to the accuracy of relay protection action in power system.For the phenomenon of malfunction caused by EFT/B in the transformer neutral point gap protection,this paper studies its impact on the transformer neutral point overvoltage.Based on the existing segmented arc model,a simplified model is proposed to reduce the difficulty of establishing the traditional simulation model.On the basis of the analysis of the field relationship of breaker,a new method is proposed to determine the alternating current (AC) arc.In order to study the circuit breaker breaking at different times,breaking of different short-circuit types,breaking at different speeds on the impact transformer neutral point over-voltage size,this paper establishes a circuit breaker model in MATLAB.The time-frequency characteristics and energy distribution characteristics of different transformer neutral point overvoltages caused by EFT/B,lightning and single-phase grounding respectively are generated by using wavelet decomposition.Further,a criterion is set up according to the high and low frequency energy ratio.The simulation results show that the criterion can distinguish the three kinds of overvoltages accurately.

关 键 词：电弧模型 电快速脉冲群 能量比 变压器中性点过电压 小波分析 

分 类 号：TM852[电气工程—高电压与绝缘技术]