高压直流输电线路行波保护影响因素分析及改进

分析了目前常用行波保护的影响因素,指出电压波形受平波电抗器和直流滤波器的影响使差分计算的电压变化率减小进而导致电压变化率保护拒动,而采用方向行波可以减小影响;方向行波变化率主要受过渡电阻影响,而电压变化量和地模波受线路损耗及色散现象影响较为严重,因此,当远距离故障时,二者定值到达时间的滞后是导致行波保护拒动的重要原因.提出了基于极性比较的不受过渡电阻影响的行波保护原理,基于该原理的行渡保护能够在区内高阻接地故障时可靠动作.基于EMTDC的仿真结果验证了所述工作的正确性和有效性.

Analysis of Influence Factors and Improvement of Traveling Wave Protections for HVDC Line

An analysis of influence factors on traveling wave protections is depicted and it is found that voltage waveform depends on the smoothing reactor and the DC filter so that the voltage change rate decreases and can cause miss-trip. To avoid this,the directional traveling wave can be adopted whose change rate is mostly influenced of the fault impedance. The absolute voltage step and the earth module wave are seriously affected by the line attenuation and dispersion of the traveling wave. Therefore,the importa...