小波包算法在电力变压器局部放电信号检测中的研究

Study on Wavelet Packet Algorithm for Detecting the Partial Discharge in HV Transformer

分析了可能存在的各种干扰源及其特征,讨论了各种干扰源进入检测系统的3种途径,并且针对不同的干扰途径提出了相应的抑制措施,同时设计了用于计算机模拟的局放检测信号。针对高频的局放信号采用快速小波包分解及重构算法,该算法对低频信号和高频信号都具有较高的频率分辨率,采用此算法对仿真的局部放电信号进行了分解与重构,仿真结果表明方法能有效地滤除强载波干扰,不失真地提取出局部放电信号幅值及其时间位置。

All sorts of disturbances and their characters are analysed and three approaches of disturbance to the partial discharge are discussed in order to eliminate all disturbances. The signals for simulating the different partial discharge signals and the disturbed partial discharge signal in HV transformer are designed. In order to extract the partial discharge pulse, a wavelet packet algorithm for decomposition and reconstruction to the partial discharge signal, which has high resolving power to the high frequency signal and low frequency signal, is adopted. Simulation results show that it can eliminate the strong carried disturbances and detect the time position and amplitude of the partial discharge signals.