引风机差动保护误动作事件分析

Analysis on Differential Protection Misoperation of Induced Fan

某电厂6 kV引风机区外故障切除后的自启动过程,差动保护发生误动作。针对该事件,从电流互感器设计选型及其二次负荷等方面进行了分析计算,得出了互感器额定输出不足导致差动保护误动作的结论,提出了提高互感器带载能力的思路,并采用更换电流互感器方案解决了保护误动作问题。

During the self-launch process after the fault outside the 6 kV induced fan area of a power plant was removed,the differential protection malfunctioned.In view of this event,analyses and calculations are carried out concerning the design selection of current transformer and its secondary load,and the conclusion is drawn that the insufficient rated output of transformer leads to the misoperation of differential protection.An idea of improving the load carrying capacity of transformer is put forward,and a scheme of replacing current transformer is adopted to solve the problem of protection misoperation.