复式电流比例差动保护判据的可靠性评估

RELIABILITY EVALUATIONS ON COMPLEX CURRENT PERCENTAGE DIFFERENTIAL CRITERION

以常规电流比例差动判据为参照 ,通过改变电流差动保护的流出电流比、流入流出 (或双流入 )电流的相位差 ,详细地分析了复式电流比例差动判据在外部故障CT饱和或内部故障有流出电流时的可靠性。并指出 :对于各种实际故障 ,复式比例差动判据在大部分情况下要优于常规比例差动判据。最后给出了复式比例差动判据的更一般的形式。

Detail reliability evaluations on complex current percentage differential protection relay in contrast to normal differential protection relay are developed in this paper. Some instances are presented to evaluate the restraint or trip behaviors of both criteria with change of the percentage of efflux current by influx current and the phasor angle between efflux and influx currents. It is figured out that the complex percentage differential criterion is better than the normal one under most conditions. In the end, a general expression of complex percentage differential criterion is put forward.