基于ITD的高压直流输电线路行波故障测距法

针对行波测距时波头到达母线时间精度提取困难的问题,提出了应用固有时间尺度分解(ITD)原理提取行波时频信息,通过ITD自适应地将故障行波信号分解得到原始信号完整的时频分布,可以准确得到行波波头到达母线的时刻.针对行波速度难以准确确定的问题,利用A型测距法与D型测距法相结合,提出了一种不受行波波速影响的测距法,以克服预设波速与实际波速存在的误差,提高测量精度.仿真实验表明:方法有效,误差精度较D型测距法好,在一定程度上提高了故障测距精度.

Travelling wave fault ranging method for HVDC transmission lines based on ITD

Aimed at problem of difficulty in extracting precision of arrival time from wave arrival at bus bar in travelling wave ranging,the intrinsic time-scale decomposition(ITD)principle is proposed to extract the time-frequency information of the travelling wave. The complete time-frequency distribution of the original signal is obtained by utilizing ITD to decompose the fault traveling wave signal adaptively,so that the accurate time for wave arrival at the bus bar can be obtained.Aiming at the problem that the traveling wave velocity is difficult to be accurately determined,a distance measuring method which is not affected by traveling wave velocity is proposed by using the A-type and the D-type distance measuring methods,so as to overcome the error between the presetted wave speed and the actual wave speed to improve the measurement precision. Simulation results show that the combination of these two algorithms is effective,and the error pre-cision is better than D-type method.To some extent,it can improve precision of fault location.