A communication interference suppression method for ultra high-frequency partial discharge detection

Because of its favorable corona resistant ability, ultra high-frequency (UHF) technique based partial discharge (PD) detection is widely applied in partial discharge detection of such power equipment as power transformer and gas insulated switchgear (GIS). However, in complicated electromagnetic environment of the substation, a great variety of UHF interference signals caused by communication such as mobile phone signals cause difficulties to on-site detection and diagnosis of the PD faults, thus it is hard to diagnose the test results accurately. According to the frequency domain features and characteristics of envelope waveform of partial discharge UHF signals, a comprehensive anti-interference approach, which is based on notch filter and cross-correlation analysis, is proposed in this paper. Analysis and test results show that the proposed anti-interference approach can suppress the interference caused by communication signals which is common in PD UHF detection, the detection sensitivity and accuracy of discharge pattern recognition can be improved.