Wavelet de-noising is a common de-noising method used in partial discharge(PD) detection, threshold estimation is closely related to distortion and error of partial discharge signals. For the purpose of improving the adaptive performances of wavelet de-noising and reducing distortion of de-noised signal, we put forward an approach of hybrid particle swarm optimization wavelet adaptive threshold estimation(HPSOWATE) for de-noising of partial discharge signals. To solve the premature convergence problem of co...