一起全站失压事故的调查分析

Investigation and Analysis on No-voltage Fault in Entire Substation

通过一座110 kV内桥接线变电站的失压事故调查,重点就差动保护电流采样回路故障导致的主变差动保护误动原因、操作回路中合位继电器HWJ与合后继电器HHJ接点的混淆使用导致的备自投拒动原因进行了详细分析,并提出了相应的防范措施。

After investigating the loss - of- voltage fault in one 110 kV substation with internal bridge connection, the masons of miss operation of main transformer differential protection are analyzed in detail, which probably is the trouble of the sampling loop of the differential protection current. The reasons of miss trip of backup power switchover unit are also discussed, which must be caused by the misuse of the contacts of close relay HWJ and the after-close relay HHJ. Furthermore, the solution methods are proposed according to the above problems.