220kV步桥变1#主变跳闸事故分析

Analysis on the accident of #1 transformer switch operation in Buqiao 220kV substation

宁夏电网步桥变一条35kV线路CT故障造成主变低压侧CT饱和,从而导致主变差动保护误动作。深入分析了此次差动保护误动作的发生原因,阐述了事故的检查处理过程,对继电保护规程中暴露出的弱点及疑点问题进行了系统地分析,并针对该误动保护的原理缺陷提出改进方案。

ACT saturation on low-voltage side of main transformer happenned casused by the CT malfunction of 35kV line in Buqiao substation of Ningxia EHV grid,which led to the wrong action of main transformer differential protection.The causes and the inspection process of this accident,as well as the weakness and doubtful point issues of relay protection regulations are systematically analyzed.Improvement measures are proposed based on the limitation analysis of misaction fault protection theory.