双极HVDC输电线路行波故障定位

为准确定位双极HVDC输电线路故障,介绍了基于小波模极大值理论的双端D型行波故障测距方法及该方法在双极HVDC输电系统中的应用并用PSCAD和MATLAB软件仿真分析双极HVDC系统,得到故障点初始行波波头分别到达整流侧母线和逆变侧母线的时刻,从而算出故障点到达两侧母线的距离,完成故障定位。该结果表明,小波变换的模极大值能够刻画出故障行波信号的奇异点和奇异性,用小波变换提取高频暂态信号可准确找出故障极线路,识别出故障极初始电流行波的波头,实现双极HVDC输电线路高度精确的故障定位。

Traveling-wave Fault Location of Double-pole HVDC Transmission System

The precise fault location of HVDC transmission line is of great significance and practical engineering value.This paper introduces the double-pole HVDC transmission system and the double terminal traveling-wave fault location method which is based on the wavelet modulus maximum theory.The wavelet transform simultaneously has the good attribute of showing partial signal in the time domain and the frequency domain,and the ability of eliminating noises.The signal singular point contains most important information,and the Wavelet Modulus Maxima can portray the signal singular point and the irregularity of traveling-wave.A double-pole HVDC system is simulated by the PSCAD and MATLAB software,and the figures of the fault current traveling-wave for the negative pole and the positive pole are got.It can be analyzed that the positive pole is the fault pole from the figures.The wavelet transform figures of the rectifier traveling wave and inverter traveling wave for the fault pole are portrayed.From the wavelet transform figures,we can easily find the precise time of the initial current traveling-wave head that arrives at both sides of the bus.Then,the distances between the fault location and the both sides of the bus are computed.The result indicates that picking-up the high frequency transition signal with the wavelet transform the fault pole can be found and the initial current traveling-wave head can be distinguished accurately.Therefore,the accurate fault location of double-pole HVDC transmission system is realized.