平行双回线对反时限零序电流保护的影响及改进算法

Influence of Parallel Double Circuits on Inverse Time-Sequence Zero-Sequence Current Protection and the Improved Algorithm

在平行双回线内部发生接地故障时,反时限零序电流保护可能会出现误动,靠近故障端的保护速动性较差,故障线路两端的保护动作存在配合程度低,且灵敏度低的问题。为解决平行双回线对反时限零序电流保护的影响,提出改进算法,通过改变时间整定系数,使反时限特性曲线上下移动,从而配合其他曲线实现反时限零序电流的保护,解决平行双回线反时限零序电流保护误动问题。设定延时时间,提高保护选择性动作的正确性,确保快速切除接地故障。通过对比实验验证改进算法的有效性,结果表明,平行双回线出现接地故障时,研究算法可以有效减少反时限零序电流保护误动情况,增强保护速动性,实现故障保护选择性动作的灵敏配合。

When the ground fault occurs inside the parallel double-circuit line,the reverse time-limit zero-sequence current protection may misoperate,and the protection near the fault end is poor in quick action and the protection at both ends of the fault line suffers from low coordination and low sensitivity.In order to address the effect of parallel double-circuit on the reverse time zero-sequence current protection,an improved algorithm is proposed in this paper.With this algorithm,the inverse time zero-sequence current protection curve is moved up and down by changing the time setting coefficient,so as to,together with other curves,realize the protection of inverse time zero sequence current and solve the misoperation problem of parallel double circuit inverse time zero sequence current protection.The delay time is set to improve the accuracy of selective protection actions and ensure quick removal of the ground fault.The effectiveness of the improved algorithm is verified by comparing experiments,and the results show that the proposed algorithm can effectively reduce the false motion of the inverse time zero-sequence current protection when the parallel double-circuit fault occurs,enhance the quick action of protection,and realize the sensitive coordination of selective actions for fault protection.