±800kV直流输电线路雷击点与闪络点不一致时的行波测距

Traveling Wave Based Fault Location With Flashover Position Different From Lightning Position for UHVDC Transmission Lines

分析了特高压直流输电线路雷击点与闪络点不一致时电压行波的传播特点。在雷击侧,由雷电流注入所引起的电压行波先到达保护安装处,而由故障引起的电压行波后到达,所检测到的电压行波起始阶段呈现出雷击未故障特征;在闪络侧,由故障引起的电压行波先到达,而由雷电流注入所引起的电压行波后到达,所检测到的电压行波起始阶段呈现故障的特征。因此,利用线路两端检测到的电压行波线模首波头幅值进行比较来识别雷击侧和闪络侧,再应用双端行波测距方法对雷击点进行定位,继而根据雷击侧电压行波首波头和故障点反射波头的时间差进一步确定闪络点的位置。仿真结果表明该方法有效。

For ultra high voltage direct current （UHVDC） transmission lines, the transmission feature of voltage wave was analyzed when the positions of lightning and flashover are different. At the side of lightning, the voltage wave caused by lightning current arrives firstly and the flashover voltage secondly. The starting period of the detected voltage wave has the feature of lightning without fault. At the side of flashover, fault voltage wave arrives firstly and lightning wave secondly. At the beginning, it shows the feature of flashover. Thus, comparing two line modulus voltage wave detected at protection positions at the terminals of transmission lines to identify the lightning side and the flashover side, then locate the lightning position using two-terminal traveling wave location method. The time difference between the first voltage wave and the reflection wave from fault position at the lightning side was applied to locate fault position. Simulation results show that the method is effective.