500kV主变保护失灵回路分析

The analysis of failure circuit of 500kV transformer protection

针对500kV主变失灵回路的特殊性,分别对主变高压侧、中压侧失灵启动回路的逻辑原理进行论述。通过对主变失灵保护的启动回路和跳闸回路的分析,总结了主变高压侧失灵回路的特点即"高压侧任一断路器拒动联跳主变三侧断路器并跳开高压侧相关断路器";中压侧断路器失灵回路的特点即"断路器失灵解除复压闭锁且不判断路器位置"。得出了主变失灵启动的判据即"电流判别+电量保护出口",电量保护启动失灵的原则——跳哪侧断路器启动哪侧失灵。

Aiming at the particularity of failure circuit of 500 kV main transformer,t his paper discusses the logic principle of start up failure circuit at high-pressure side and middle-pressure side. Through the analysisof the start-up and trip circuit of failure protection of main transformer,it points out the characteristic of the failure circuit in high-pressure side of main transformer is that ＂when the high side breaker refuses to trip,t he breaker of three sides and the high-side associated will be tripped＂,and the characteristic of the failure circuit in middle-pressure side transformer is that ＂when circuit-breaker failures,the complex voltage lockout should be removed and breaker location is not judged＂. T he failure start-up criterion of main transformer is educed,namely ＂current discrimination ＋ power protection exit＂,and the principle of electricity protection start up failure is that failure protection at the side which trips should be started.