中性点非有效接地系统电压互感器故障分析与治理措施研究  

Study of Potential Transformer Fault and Mitigation Measures in Power System with Non-direct Grounding Neutral Point

作　　者：申文伟 何峰 鲍新 白凡 房民 朱鸿燕 孟繁国 张冠军[2] 田燕山 SHEN Wenwei;HE Feng;BAO Xin;BAI Fan;FANG Min;ZHU Hongyan;MENG Fanguo;ZHANG Guanjun;TIAN Yanshan(Ji＇nan Power Supply Company, State Grid Shandong Electric Power Company, Ji＇nan 250012, China;State Key Lab of Electrical Insulation and Power Equipment, Xi＇ an Jiaotong University, Xi＇ an 710049, China;State Grid AC Engineering Construction Company, Beijing 100052, China)

机构地区：[1]国网山东省电力公司济南供电公司,济南250012 [2]西安交通大学电力设备电气绝缘国家重点实验室,西安710049 [3]国家电网公司交流建设分公司,北京100052

出　　处：《高压电器》2018年第7期200-205,共6页High Voltage Apparatus

摘　　要：目前10~35kV中性点非有效接地系统内电压互感器(PT)高压熔断器熔断、互感器烧毁等故障(统称PT故障)频发,严重威胁电力系统的安全运行。文中统计分析了电网系统内26起PT故障,探讨了PT故障的深层原因,并结合故障原因对现有的各类消谐方式进行了对比研究。研究发现,PT故障的本质原因是PT过励磁导致热损坏,具体可归为两类原因,88%的PT过励磁故障由间歇性弧光接地过电压引起,均发生在10kV中性点经消弧线圈接地系统;仅有12%由铁磁谐振过电压引起,均发生在35kV中性点不接地系统。笔者认为,抑制PT过励磁的关键是限制PT本身承载的弧光接地过电压和铁磁谐振过电压。然而,现有的消谐措施多侧重于消除铁磁谐振过电压,对弧光接地过电压的限制不够有效。基于上述分析,文中推荐一种新型热敏电阻限流消谐装置,兼有PT限流与消谐功能,具有优良的"自适应"特性,初步应用效果良好,能够有效防止PT故障发生,具有广阔的应用前景。The fusing of potential transformer（PT）fuse and the burning of PT（generally referred to as the PT fault）occur multi-times in non-direct grounding neutral system, which is a serious threat to the safe operation of power system. In this paper, the causes of 26 PT faults in the grid system and the present protective measures are analyzed. It is found that the fundamental cause of PT fault is PT over-excitation and over-heating damage, 88% of which is caused by intermittent arc grounding overvoltage（in 10 kV grounding neutral system via arc suppression coil）, and only 12% of which is caused by ferro-resonance overvohage（in 35 kV non-grounding neutral system）. The key to inhibiting PT overexcitation is to limit the arc grounding overvohage and ferro-resonance overvoltage. The present measures are merely focused on eliminating the ferro-resonance overvoltage, while the limitation of the arc grounding overvohage is not effective. Therefore, a new type of thermistor device with both current limiting and resonance elimination functions is highly recommended. The technique employs both current limiting and resonance elimination functions, which shows excellent adaptive feature and good effect of PT fault elimination and enjoys a promising prospect in application.

关 键 词：电压互感器 弧光接地 铁磁谐振 过励磁 限流消谐电阻 

分 类 号：TM451[电气工程—电器]