二级电站1号主变差动保护误动作的原因分析及处理

Cause Analysis and Treatment of Differential Protection Malfunction of No.1 Main Transformer in Cascade II Power Station

二级电站1号主变保护装置至投运以来,曾发生过多次主变差动保护误动,导致运行设备停电,影响电力系统的稳定运行。通过“人员对主变差动保护接线工作原理的理解程度”“二次安全措施的执行情况”“差动保护各侧CT极性接线是否正确”“CT二次回路接线是否松动”“用于差动的CT是否一点接地”“保护装置内部定值整定是否正确”“保护装置是否超期运行”“误短接出口跳闸回路”“励磁涌流是否过大”等方面分析查找主变差动保护动作的原因,并加以处理,达到主变差动保护可靠运行的目的。

Since the protection device of No.1 main transformer of cascade II power station was put into operation,there have been many misoperations of differential protection of main transformer,resulting in power failure of operating equipment and affecting the stable operation of power system.The reasons for the action of the main transformer differential protection are analyzed and found through various aspects,such as"personnel's understanding of the working principle of the main transformer differential protection wiring","the implementation of secondary safety measures","whether the CT polarity wiring on each side of the differential protection is correct","whether the CT secondary circuit wiring is loose","whether the CT used for differential is grounded at one point","whether the internal setting of the protection device is correct","whether the protection device runs beyond the time limit","misconnection the outlet tripping circuit","whether the inrush current is too large".And it is treated to achieve the purpose of reliable operation of main transformer differential protection.