380 V给煤机MCC跳闸原因分析及改进措施

Cause Analysis and Improvement Measures of MCC Trip of 380 V Coal Feeder

某380 V给煤机电动机控制中心(MCC)所带负荷发生接地故障,越级跳闸造成给煤机MCC电源进线断路器跳闬,给煤机全部失电,导致机组降负荷。针对此次故障,分析了380 V厂用电系统接地故障造成越级跳闸原因,认为当短路电流为250~480A时,框架断路器会先于塑壳断路器动作跳闸。并提出了优化保护配置,合理整定保护定值等改进措施。

A grounding fault occurred in the load carried by a 380 V coal feeder MCC.The skip trip caused the coal feeder MCC power input circuit breaker tripping,and the coal feeder lost power,resulting in the unit load reduction event.In view of this fault,the reason of tripping caused by grounding fault of 380 V auxiliary power system is analyzed,and it is considered that when the short circuit current capacity is from 250 A to 480 A,the frame circuit breaker will trip before the trip of molded case circuit breaker.Some improvement measures are put forward,such as optimizing protection configuration and setting protection value reasonably.