方向高频保护的动作行为 第二部分:复故障情况下方向高频保护的动作行为分析

PERFORMANCE ANALYSIS OF POWER LINE CARRIER PROTECTION FOR TRANSMISSION LINES PART II: STUDY ON PERFORMANCE OF POWER LINE CARRIER PROTECTION UNDER MULTIPLE FAULT

复杂电力系统发生复故障时 ,方向高频保护可能正确动作也可能不正确动作 ,而继电保护的不正确动作将直接危害电力系统的安全稳定运行。为了检验方向高频保护在复杂电力系统发生复故障情况下的动作性能 ,本文采取理论分析和 EMTP仿真相结合的方式 ,对各种方向高频保护及其方向元件在区内外同时发生故障和区外发生复故障两种故障情况的动作行为进行了研究。结果表明 :在多数复故障情况下 ,方向高频保护能够正确动作 ;但是当区内经高阻短路并伴随区外不对称故障时 。

While multiple faults occur in complex power system, the pilot protections could correctly operate or not, and incorrect operation of the pilot protection is harmful to the power system. To inspect the performances of the pilot protections under such conditions, this paper studies the actions of various types of pilot protections and corresponding directional elements by both theoretical analysis and EMTP simulations. Two types of multiple faults are inspected: the multiple faults consist of both internal fault and external fault, and the multiple faults consist of only external faults. The results show that the pilot protections will operate correctly under most multiple faults. However, while an internal high-resistance fault occurs accompanied by external unsymmetrical faults, some pilot protections might mis-operate.