盘南电厂地网电位差引起500kV断路器偷合事件的分析及反措  

Analysis and Solution of 500 kV Breakers Mis-operation in Pannan Power Plant Caused by Potential Difference of Grounding Grid

作　　者：李谦 陆明[2] 胡越冬 张波[4] LI Qian;LU Ming;HU Yuedong;ZHANG Bo(Electric Power Research Institute of Guangdong Power Grid Co.,Ltd.,Guangzhou 510080,China;CSG Power Dispatching Control Center,Guangzhou 510663,China;Guizhou Yueqian Electric Power Co.,Ltd.,Panzhou,Guizhou 553505,China;Tsinghua University,Beijing 100084,China)

机构地区：[1]广东电网有限责任公司电力科学研究院,广州510080 [2]中国南方电网电力调度控制中心,广州510663 [3]贵州粤黔电力有限责任公司,贵州盘州553505 [4]清华大学,北京100084

出　　处：《南方电网技术》2018年第4期39-47,共9页Southern Power System Technology

摘　　要：大型接地网网内电位差问题尚未引起重视。针对西电东送大通道的枢纽电厂——贵州盘南电厂在500kV电流互感器接地故障期间误合1台500kV断路器的严重事件进行仿真分析,指出异常高的地网电位差对二次控制电缆的信号干扰导致保护误动作的潜在事故扩大的问题普遍存在,提出降低网内电位差的接地网完善整改措施,以降低保护误动或拒动的风险。本方法适合用于发电厂、换流站和变电站等大型或超大型接地网的安全性评价和优化设计。为顺应电网的安全和精益化发展要求,应摒弃主要强调接地阻抗单一指标的理念,转而关注地电位升、网内电位差、跨步电位差和接触电位差等安全性指标。Potential difference in large grounding grid has not been concerned so far.By simulating analysis of a serious fault of the 500 kV breaker mis-operation during a 500 kV current transformer grounding fault in Pannan Power Plant in Guizhou province,the paper points out that abnormal high ground potential difference would likely interfere the signals in secondary control cable,cause secondary system relay protection mis-operation,and lead to a latent accident extension.A corresponding solution to reduce grounding grid potential is presented to reduce the risk of mis-operation or failure to operate.The scheme is suitable for both of the optimizing design and safety evaluation of large grounding grid of power plant,converter station or substation.To adapt to the developing requirements for grounding grid safety and streamline,single index that focuses only on grounding impedance should be discarded,and multiple safety indices should be attended to,such as ground potential rise,potential difference within grounding grid,step voltage and touch voltage.

关 键 词：大型接地网 电位差 二次系统 继电保护 误动作 

分 类 号：TM561[电气工程—电器]