小电流接地系统单相接地故障选线防止误判的有效方法探讨

Study of Effective Meatures for Avoiding Misjudgement in Detecting Phase-to-ground Fault in Ineffectively Grounded Systems

目前小电流接地选线装置在现场运行的效果大多不很理想 ,针对这个问题 ,依据在华北电力大学小电流接地实验室进行的几千次实验 ,找出了影响选线正确的原因 ,并提出防止误判的几种有效措施 :改变 PT接线方式 ,避免铁磁谐振对选线的影响 ;增加抗干扰的软措施 ;

The domestic devices for detecting phase\|to\|ground fault in ineffectively grounded systems are seldom functional at present. Based on thousands of experiments in the high\|voltage laboratory of the North China Electric Power University , the reasons for misjudgement are found out and the effective meatures to avoid the misjudgements are presented in this paper:to change PT connection form to prevent from ill effects of ferro resonant overvoltage; to increase soft meatures to risist against interference; to adopt compositive method.