Noise Discrimination Method for Partial Discharge Current Focused on Damped Oscillation Waveform. Issue 6 (30th March 2018) - Torii, Hirotaka
SUMMARY: Online partial discharge (PD) measurement is very important for insulation monitoring of high‐voltage equipment. One of the biggest challenges performing online monitoring is discrimination between PD detect signals and external noises. Experimental results using high‐frequency current transformer (CT) sensor show that the current waveforms associated with various PD signals are all damped cosine waveforms, and have unique frequency and decay times of damped oscillation. Therefore, we focused attention on the damped oscillation waveform of the PD current, especially damped cosine waveform having a different number of oscillations. In addition to this, the noise discrimination method using wavelet transform or short‐time Fourier transform is effective. Those noise discriminating processes are applicable to online PD current measurement system.