保护用电流互感器的特性检测及应用分析

Characteristic test and application analysis of protection’s CT

通过对某一变电站变压器保护在出线故障时跳闸事件的深入调查,根据故障电流值、现场保护整定值、电流互感器及其二次回路检测数据,分析判断出误动是由于出线电流互感器保护用绕组特性与二次回路配合不当造成的。为防止类似事件的发生,从现场已安装设备出发,通过对电流互感器的二次绕组伏安特性、二次回路负载进行检测、核算,提出了利用提高额定电流比、降低二次回路负载、选用特性满足要求的二次绕组或更换电流互感器、对速断保护定值进行限制等解决方法。

This paper inquired thoroughly into the matter of transformer relay protection equipment operated when the outgoing line was malfunction in a substation. According to the fault current, relay setting current, the data of current transformer and secondary loop by checkout, it presents that error action is caused by wrong corrdination of the characteristic of secondary winding of current transformer of outgoing line with secondary loop load. To against the similar mistakes, it test and calculates electrical installations, the V/A characteristic and loop load and puts forward methods of raising rated transformation ratio, lowering loop load, selecting good secondary winding or current transformer, and restraining relay setting current.