基于电流相似度与高频能量的串联故障电弧检测方法

故障电弧是引起电气火灾的重要原因,针对非线性负载工况下故障电弧保护算法的误动作和拒动作问题,提出一种基于电流相似度与高频能量的串联故障电弧检测方法。参照标准搭建故障电弧实验平台并进行实验,从时域、频域角度分析电弧电流特征。采用小波函数预处理电流信号,选取电流低、高频特征量。设定故障电弧特征量阈值,以此为基础提出故障电弧识别算法。实验结果表明,该算法能够准确识别多种负载条件下的故障电弧,且未发生误动作和拒动作。

Series Arc Fault Diagnosis Based on Current Similarity And Wavelet Energy

Arcing Fault is an important cause of electric fire. In order to solve the issues of unwanted tripping or rejected action that the existing arc fault protection methods have, a series arc fault detection method based on current similarity and high frequency energy is proposed. According to GB/T 31143, an arc fault experiment platform was built to carry out fault arc experiments under linear and nonlinear loads and their combination. And the characteristics of arc current were analyzed from the perspectives of time domain, frequency domain and "periodic similarity". Then Db 5 wavelet was selected for arc current preprocessing, the difference of cosine similarity of adjacent periodic current low-frequency approximation coefficient was used as the low-frequency feature of arc current, while the wavelet energy in frequency range of 3125 Hz~6250 Hz was used as the high frequency feature of arc current. On this basis, a fault arc diagnosis algorithm based on threshold comparison is proposed. Experimental results show that the proposed method can accurately identify fault arcs under single load and combined load conditions, and its arc detection time meets relevant standards.