小电阻接地系统线路零序保护拒动原因分析

Zero Sequence Protection Action Refusal Cause Analysis of Small Resistance Grounding System

根据小电阻接地方式下的零序保护原理,介绍了小电流接地系统零序保护不动作的原因,分析了一起线路零序保护由于存在保护死区致使故障范围扩大的案例,通过对如何防止零序保护拒动问题进行探讨,提出了相应的反事故措施及其对策,为防止线路零序保护死区故障,建议其零序电流采用三相电流互感器合并而成,并制定有针对性的保护定值调整方案,为设备安全稳定运行提供保障。

According to the zero sequence protection principle under the small resistance grounding method, this paper introduced the zero sequence protection action refusal cause of small resistance grounding system and analyzed a case of line zero sequence protection due to existing of protection dead zone leading to fault range expansion. This paper discussed how to prevent the zero sequence protec-tion action refusal problem from taking place and raised the corresponding fault countermeasures. In order to avoid dead zone faults of line zero sequence protection, this paper suggests that the zero sequence current should be merged in three-phase current transformer and the protection setting value adjustment scheme should be set down to provide insurance for safe and stable operation of equipment.