差动保护的暂态可靠性

The transient reliability of differential protection

差动保护的暂态可靠性取决于电流互感器的精度和差动继电器的动作特性。文中分析了P类电流互感器的暂态误差 ,提出了加倍P类TA的准确极限系数以限制其暂态误差。另一方面通过提高比率制动系数 ,对差动电流进行波形鉴别和采取快速测量可使差动继电器能避开暂态不平衡电流 ,只要求TA能在故障后 2ms内保持线性变换。所提出的快速测量方法不需要另外增加快速动作的故障检测元件捕捉故障起始的时刻。

The transient reliability of the differential protection is detemined by the accuracy of the current transformer and the characteristics of the differential relay.The transient error of the class P current fransformer is analyzed.A suggestion is promoted to limit the transient error by double the accuracy limit factor of the class P current transformer.On the other hand by increasing the restraint coefficient,discriminating the wave form of the differential current and fast measuring the differential relay may override the transient unbalance differential current even the current transformer can keep linear transformation only about 2ms.The method of fast measuring recommended does not require an additional fast operating fault detector to catch the fault starting time.