一种输电线路超高速方向保护方法

通过深入分析故障暂态电流在超高压母线系统中的传播特性、故障初始角与暂态电阻对故障高频暂态电流能量影响,首先将母线两侧故障高频暂态电流的能量作差,然后将故障高频暂态电流能量差按照故障初始角与暂态电阻进行归算,利用归算后的故障高频暂态电流能量差可以准确判断故障方向。根据线路两端的方向判断结果便可准确判断被保护线路是否故障。该保护方法消除了故障初始角与暂态电阻对暂态保护的影响,具有高可靠性和灵敏度。在三相500k V电力系统中,考虑各种典型故障情况,使用ATPDraw对该算法进行了大量仿真分析。仿真结果表明,应用该算法实现超高输电线路的超高速保护是可行的。

A Method for Directional Ultra-High-Speed Protection of Transmission Lines

A new directional protection of EHV power transmission lines was presented based on the propagation characteristics generated by fault high transient current. In the procedure, the energy difference of fault induced high transient current was obtained from the two lines connected with the same bus. Then, the energy difference was normalized by initial fault angle and transient resistance. According to the normalized energy difference, the positive direction of fault can be correctly discriminated from negative direction. Based on the fault directions of the line at two endings, whether a fault occurs on the protected line can be determined. The proposed method eliminated the influence of the initial fault angle and transient resistance, and has high reliability and sensitivity. Simulation results verified the feasibility of the method for EHV transmission lines.