小电阻接地系统灵活高阻接地保护研究  

Research on Flexible High Impedance Grounding Protection of Low-resistance Grounded System

作　　者：董凯达 蔡燕春 余群兵 张少凡 DONG Kaida;CAI Yanchun;YU Qunbing;ZHANG Shaofan(NR Engineering Co.,Ltd.,Nanjing,Jiangsu 211102,China;Guangzhou Power Supply Bureau Co.,Ltd.,Guangzhou,Guangdong 510620,China)

机构地区：[1]南京南瑞继保工程技术有限公司,江苏南京211102 [2]广州供电局有限公司,广东广州510620

出　　处：《广东电力》2019年第1期109-117,共9页Guangdong Electric Power

基　　金：广州供电局有限公司科技项目(GZHKJ00000020)

摘　　要：针对传统零序过流保护整定不能反映高阻接地故障以及专用零序CT极性校验困难的问题,分析了小电阻接地系统发生接地故障时的零序功率分布特征,在此基础上提出一种小电阻接地系统灵活高阻接地保护。该保护基于零序有功功率绝对值大小以及零序有功、无功功率绝对值比例进行判别,能够可靠识别高阻接地故障线路。判据中采用零序有功、无功功率的绝对值,与VT/CT极性无关,不受专用零序CT极性接反的影响。该保护还具备脉冲计数跳闸功能,能够适应间歇性高阻接地的情况,解决常规保护在间歇性接地时因计时达不到从而无法跳闸可能导致故障扩大的问题。To solve problems of traditional zero-sequence over-current protection setting being unable to reflect high impedance ground fault and difficulty in verifying polarity of zero-sequence current transformer (CT),this paper analyzes distribution characteristics of zero-sequence power as ground fault occurs in the low resistance grounded system,and then proposes a kind of flexible high impedance grounding protection.This protection is based on absolute value of zero-sequence active power and ratio of absolute values of zero-sequence active power and zero-sequence reactive power for discrimination and is capable of reliably identifying grounding faulted lines.Absolute values of zero-sequence active power and zero-sequence reactive power for discrimination,which are unrelated with polarity of voltage transformer (VT) and CT and will not be affected by reversed polarity of the exclusive zero-sequence CT.This protection is provided with function of pulse counting tripping,which is adaptive to intermittent high impedance grounding and solve the problem of fault expansion due to failure in tripping caused by unreached delay time of traditional protection in intermittent grounding.

关 键 词：小电阻接地系统 高阻接地 间歇性接地 零序功率 零序保护 

分 类 号：TM773[电气工程—电力系统及自动化]