方向行波波形积分式快速母线保护

Fast Busbar Protection Based on Waveform Integral of Directional Traveling Waves

为提高母线保护的动作速度,根据行波传输理论,提出一种行波波形积分式快速母线保护方法。当母线故障时,在所有出线上检测到的初始行波均来自于线路的背后,是正向行波;而某条出线发生故障时,在所有非故障线路上检测到的初始行波是正向行波,而故障线路上检测到的初始行波是反向行波。在故障后特定时间内对各条出线上的方向行波进行积分运算,根据正反向行波积分值的比值大小识别故障方向。综合分析所有出线的故障方向,可识别母线是否发生故障。利用PSCAD/EMTDC构建了500 k V母线模型,仿真结果表明:所提方法鲁棒性强、动作快速、可靠性高,其性能基本不受故障电阻、故障初始角、开关操作等的影响,有望应用于实际的电力工程中。

Using the propagation theory of traveling waves, a fast busbar protection method based on waveform integral of traveling waves is presented to improve the operation speed of busbar protection. For a busbar fault, the detected traveling waves on all lines connected to the busbar will come from their back, whose directions are defined as positive. For a fault on any one of these lines, the detected traveling waves on all healthy lines have the same positive direction, while the traveling wave direction on the faulted line is negative. Within a special duration after the fault, the waveforms of directional traveling waves on all lines are integrated, and a criterion discriminating fault direction can be established according to the ratio of directional traveling waves. Through analyzing the fault directions for all lines, whether the busbar fault is internal or not can be identified. Using PSCAD/EMTDC, a 500 kV busbar model was constructed. Simulation results show that the proposed method has good adaptability, fast operation speed and high reliability, and the performances are immune to fault resistances, fault inception angles, circuit breaker operation, etc. It is promising to be applied in the actual power engineering.