小波分析应用于直流系统接地故障检测

针对直流系统接地故障检测中常用的低频信号注入法容易受到各支路电缆中存在的对地电容的影响这一问题，提出了利用小波分析实现故障信号特征的提取的方法。分析了低频信号注入法的原理及存在的缺陷，针对其故障信号的特点，提出了基于小波变换的直流系统接地故障检测方案。基于小波去噪的原理，通过选择适当的小波函数，对支路电流信号进行分析和处理。经过仿真实验分析。表明该方法可以克服对地电容对接地故障检测的不利影响，完成故障信号分析，实现故障支路的准确定位。

Grounding Fault Detection of DC System Based on Wavelet Analysis

To solve the problem that the method of low frequency signal injection used to detect DC system grounding fault is influenced by the capacitors between ground and each branch, wavelet analysis is used to extract the characteristic of signal. The principle and existing defects of low frequency signal injection method are analyzed, According to the characteristic of faulting signal, a detection scheme based on a wavelet transform for fault in DC system is proposed. The current signal of the branch is analyzed and processed by selecting the suitable wavelet function on the basis of the principle of wavelet denoising. The simulation result shows that the method can overcome the influence of the capacitors, analyze the fault signal and find the fault branch accurately.