基于小波熵的直流系统环网接地故障诊断

Loop net grounding fault diagnosis of DC system based on wavelet entropy

针对直流系统中环网对接地故障检测的影响,在传统低频信号注入法的基础上提出了一种新的基于小波熵理论的直流系统环网接地故障检测方法。该方法利用小波分析具有时频局部化特性和熵能对系统状态表征的特点,将小波分析和熵结合起来完成信号的特征挖掘。通过低频信号注入,采集环网状态,计算小波熵作为系统的特征参数,以小波熵来识别不同情况的接地故障。仿真分析证明,小波熵能够反映环网发生接地故障前后的系统变化,用小波熵来提取环网故障信息并进行故障识别是一种行之有效的方法。

According to the influence of loop net on DC system fault detection, a new method based on wavelet entropy theory to detect grounding fault in loop net of DC power system is proposed in view of traditional low frequency signal injection method. The method combines wavelet analysis with entropy theory to accomplish signal characteristic mining by exploiting the time-frequency localization ability of wavelet analysis and the ability of entropy to token system state. By injecting low frequency signal and gathering state of loop net, wavelet entropy is calculated as system characteristic parameter and then the fault branch can be found. It is verified by simulation results that wavelet entropy can reflect the system change of grounding fault of loop net. The method is effective for extraction and recognition of fault information of loop net.