基于小波去噪的配电网C型行波故障测距

C-Type Traveling Wave Fault Location of Distribution Network Based on Wavelet Denoising

对于配电网C型行波测故障测距方法,通常将故障相和非故障相的电压差作为测量信号进行故障测距。但是对于实际配电网系统,分支对信号的衰减和噪声的干扰常使测量信号湮没在噪声中,使得算法失效。提出一种基于小波重构的配电网行波去噪方法,利用小波分析对信号进行多尺度分解、重构去噪提取故障信号。与传统的去噪方法相比,去掉了信号高频部分,减小了在实际配电网中由于噪声对测量信号行波波头提取的影响,仿真结果表明该方法的正确性。采用PSCAD/EMTDC仿真软件,建立中性点非有效接地的系统仿真模型,仿真结果表明基于小波去噪的配电网C型行波故障测距的可行性。

When C - type traveling wave is used in transmission line fault location, the voltage difference of faulty phase and normal phase is usually treated as the measurement signal. However, in real distribution network, the measurement signal is attenuated by branches and annihilated by noises, thus this method is ineffective. A denoising method for traveling wave in distribution network based on wavelet reconstruction is proposed. This method decomposes the signal in multi - scales and re- constructs it to reduce noises within the signal. Compared to the traditional denoising methods, the high - frequency part of the signal which is considered to contain noises is removed. As a result, the influence of noises is reduced and the simulation results prove its effectiveness. A simulation model of a system with neutral point non - effectively grounded is established using PSCAD/EMTDC. The simulation results prove the feasibility of C - type traveling wave fault location based wavelet denoising in distribution network.