一起接地变压器电流保护误动作案例分析

Analysis of a Case of Misoperation of Grounding Transformer Current Protection

在变电站35kV及以下系统中可通过加装接地变压器将中性点接地方式改造为小电阻接地方式,针对由此带来的故障特征变化可能造成保护装置误动作的问题,结合接地变压器的工作原理、电流保护配置和整定情况,分析电流保护误动作的原因。通过一起接地变压器电流保护误动作的故障案例,阐述保护装置动作过程和事故调查情况,确定保护装置误动作的原因,并提出相应的改进措施。

In substations,the grounding mode in systems of 35 kV and below can be modified to a low resistance grounding mode by installing grounding transformers.Considering the possibility of protection device misoperation caused by the changes in fault characteristics brought by this,the causes of current protection misoperation are analyzed in combination with the working princi-ple of grounding transformers,current protection configuration and setting.Through a case of misoperation of grounding transform-er current protection,the operation process of the protection device and the accident investigation situation are elaborated,the causes of protection device misoperation are determined,and the corresponding improvement measures are proposed.