一例直流两点接地导致的保护误动分析

Analysis on a Protection Misoperation Accident Caused by DC Two-point Grounding

描述了一例直流两点接地导致保护误动的事故案例,通过对直流系统绝缘监测仪平衡电桥原理、CSC241变压器综合保护测控装置开关量输入电路的分析,得出直流系统两点接地、综合保护测控装置开关量输入电路设计不当共同导致了事故的发生,并对直流电源回路日常检修维护,跳合闸线圈及开关量输入采集电路的设计提出了建议。

An accident of protection misoperation caused by DC two-point grounding is described in this paper.The analysis on the balanced bridge principle of DC system insulation monitor and the binary input circuit of CSC241 transformer integrated protection measurement and control device led to the conclusion that the DC system two-point grounding and the improper design of the binary input circuit of the measurement and control device commonly led to the accident.Finally,suggestions are given on routine maintenance of the DC power supply circuit and the design of the binary input circuit.