Periodic Narrow-Band Noise Denoising of Partial Discharge Signal Through Time-Frequency Analysis

In high voltage engineering, partial discharge (PD) is an important topic. PD measurement is frequently used to monitor the status of critical equipment such as power transformer, gas insulated switchgear, and cable. The measured PD signal is of great importance for insulation evaluation and fault diagnosis. However, PD signal easily gets corrupted by periodic narrow-band noise, which will cause interference and finally lead to misjudgment of insulation status. Therefore, it is necessary to denoise it in the measured PD signal. In this paper, time-frequency analysis is proposed for denoising. Instantaneous frequency (IF) is also introduced. Due to the different IF characteristics between pure PD signal and periodic narrow-band noise, it is possible to distinguish and separate them. Numeric simulation experiments have been carried out to verify the feasibility of the proposed method.