110kV变电站变压器差动保护动作原因分析

Analysis of mal-operation of transformer's differential protection in a 110kV substation

对某110 kV变电站变压器差动保护动作原因运用波形及向量法进行了详细分析,同时分析了在单相接地故障情况下,主变高压侧出现三相电流幅值,相位基本一致的情况,得出了“变压器绕组接法、保护内部算法变换方法与电流互感器接法的正确匹配”是保护正确动作的首要条件的结论,提出了改进措施,旨在更好地完善变压器保护的运行和维护。

The reasons of mal-operation of the transformer differential protection in a llOkV substation are detailed. It is found that the magnitude and the phase of three phase currents on the high-voltage side of the transformer are basically equal when single-phase ground fault occurs. The improved method for the transformer differential protection is presented.