反时限过电流保护与改进距离保护整定的配合

配电网中距离Ⅱ段保护与反时限过电流保护作为主/后备保护对时,为了满足选择性要求,通常会增加距离Ⅱ段保护和反时限过电流保护的动作时间。对此,提出了一种改进保护动作特性的保护配合方案,改进后的距离保护将距离Ⅱ段保护分拆为两个阶段,与之相配合的反时限过电流保护动作曲线在T-L坐标系中自适应向下移动,以此可减小主保护和后备保护的动作时间。IEEE8节点系统仿真结果表明,改进后的保护方案在主/后备保护对满足选择性的基础上,能减小系统的平均动作时间,提高保护的速动性,且保护配合无需通信设备。

Method of Inverse-time Overcurrent and Distance Relays Coordination Based on Improved Tripping Characteristic for Distance Relays

In combined coordination of distance and inverse-time overcurrent relays, operating times of the second zone of distance relays and the times of overcurrent relays are typically increased in order to satisfy the selectivity constraints. In this study, a new operating characteristic for distance relays was proposed. In the proposed operating characteristic, the common characteristic for the second zone was divided into two sections and the IP&TDS of the overcurrent relay were carried out, which decreases the time of the main relay and the back relay. In the IEEE 8-node system, the simulation results show that the improved protection scheme can reduce the average time of the relay and improve quick action performance without need of communication device.