When the noise is high,the performance of injection frequency estimation decreases significantly.Therefore,a method for estimating the injection frequency of hetero frequency signals for ground fault localization is designed.Design a signal collector composed of power supply unit,induction unit,and digital unit to collect three-phase voltage signals and zero sequence voltage signals for grounding fault location.Design analog filters and digital filters separately to filter the injected signal.Estimate the injection frequency of the filtered injected signal through the SDFT algorithm,and achieve the estimation of the injection frequency of the abnormal frequency signal for grounding fault location.Test the injection frequency estimation performance with a fixed SNR of 40 dB.The test results indicate that as the frequency increases,the standard deviation of the frequency estimation results is always low,and the overall variation is relatively stable.This method has been proven to have good anti noise performance and can accurately estimate the frequency of the injected abnormal frequency signal during ground fault location.
关键词
接地故障定位/信号采集器/模拟滤波器/异频信号/注入频率估计
Key words
ground fault location/signal collector/analog filter/abnormal frequency signal/injection frequency estimation
维普
万方数据