基于小波变换的高压直流输电线路暂态电压行波保护

A novel scheme of HVDC transmission line voltage traveling wave protection based on wavelet transform

详细研究了高压直流输电线路发生故障后暂态电压行波的能量分布特征,利用小波变换对暂态电压进行多尺度分析,并使用电磁暂态仿真软件PSCAD/EMTDC对直流线路在区外和区内故障、故障性雷击和非故障性雷击等几种典型故障下,直流线路暂态电压在各个小波分解尺度下的能量分布进行了仿真计算。计算结果表明,当直流线路发生不同类型故障时,其暂态电压的低频与高频能量的比值有较大差异。根据这些特征,构成了一种新的高压直流线路行波保护判据。

This paper researches transient voltage traveling wave energy＇s distributed characters of HVDC transmission line after faults occur and uses wavelet multi-resolution signal decomposition technique to analyze the various transient voltages. It makes simulations for various faults using electromagnetism emluator PSCAD/EMTDC and calculates its energy distribution by wavelet multi-resolution signal decomposition technique, including faults inside DC lines, fault outside DC lines, fault lightening strike and non-fault lightening strike. The calculation results indicate that when different faults occur on the DC lines, the ratio of low frequency and high frequency energy of transient voltage traveling wave differs largely. Based on these characters, an excellent performance traveling wave protection criterion is put forward.