A Denoising Method of Partial Discharge Signal by Dual Coupling Capacitors

Partial discharge (PD) acts as a preliminary indicator of the degradation of motor insulation. The PD measurement process is susceptible to many types of electromagnetic interference (EMI), resulting in signal distortion and inaccurate fault evaluation. This work introduces an anti-interference technique utilizing a multi-coupler design to tackle the problem of inadequate interference suppression on-site. This method utilizes the variances in the transmission pathways of PD signals and external noise to mitigate interference. Furthermore, assessments are performed on the models of corona discharge and surface discharge. The results demonstrate that this method effectively reduces power frequency interference, white noise, and pulse-type disturbances, improving the signal-to-noise ratio and accurately capturing the phase, amplitude, and other characteristics of PD signals, thus providing a reliable basis for evaluating the insulation condition of equipment. The testing validated the efficacy of the multi-coupler arrangement and the differential method in reducing interference during PD measurements, offering technological advice for interference mitigation in engineering applications.