变压器和应涌流现象及实例分析

根据一起现场发电机差动保护误动录波数据验证了变压器空载合闸时相邻变压器中和应涌 流的存在,分析了保护误动的原因。与空载合闸变压器相邻的变压器产生的和应涌流引起低压侧 发电机定子电流增大,在发电机定子电流变化的过程中,发电机差动两侧电流互感器的传变特性发 生改变,从而使差动保护两侧电流相位偏离了正常值,导致发电机差动保护误动。根据现场的实际 情况和误动原因,文中给出了几种解决方案。

Phenomenon of Sympathetic Inrush and Analysis of an Example

It is shown that sympathetic inrush may occur in the adjacent transformer when a no-load transformer is switched, and the causes of mal-operation are analyzed for the generator differential protection mal-operating wave data. The transfer characteristics of the current transformer are changed by the sympathetic inrush, which leads to a deviation of the phase-angle between the currents used by generator differential protection, resulting in the generator differential protection mal-operation. Some measures are proposed to prevent the differential protection from mal-operation by taking into account the field situation and the causes of mal-operation.