计及模速差异与杂散电容的反向行波辨识

Identification of Reverse Traveling Wave Considering Modular Velocity Difference and Stray Capacitance

单端法是行波测距研究的热点,但第2个浪涌波头的辨识因非故障线路及故障对端母线的存在变得困难。为此藉助故障行波线模与零模波速的差异提出一种区分故障半程内外的辅助判据。反向行波虽能有效抑制相邻非故障线路行波折射的影响,但仅基于极性比较的方法并不能准确地辨识出第2个电压行波,故考虑电压行波在实际变电站母线杂散电容处的传播特性,即电压行波在杂散电容处的初始反射系数恒为负的结果而利用第2个反向行波相对极性进行波头辨识。理论分析和实际仿真结果表明,这种方法不受线路两端母线类型影响,对单端行波测距法的有效实施有非常现实的意义。

Fast fault location can enhance the speed of examination, repair and restoration, as well as operation stability and reliability. Single-ended transient locator has high quality and correspondingly inexpensive investments compared with double-ended one. In accordance with the bottleneck of identifying the second traveling wave based on single-ended location method, this paper presented an auxiliary criterion to distinguish whether the fault was close-in or remote half using velocity interval between aerial and ground modes at first. Though reverse traveling wave can reject the influences of waves from adjacent healthy lines, the approach purely based on polarity comparison could not accomplish the identification of the second traveling wave perfectly. Because of the existence of stray bus capacitance, the promulgation characteristics of traveling wave change and the initialized reverberation coefficient of voltage traveling wave is always negative. Accordingly, a novel approach to identify the second reverse traveling wave using its＇ relative polarity is proposed, Theoretical analysis and simulation results show that the method is applicable for all actual bus types.