A Novel Partial Discharge Pulse Separation Method for Variable Frequency Resonant Test

Variable frequency resonant test is one of the most used test methods in power equipment diagnosis. However, the severe pulse interference generated by the variable frequency power source hinders its further application in partial discharge (PD) detection. For this reason, a PD separation method based on clustering by fast search and find of density peak (CFSFDP) is proposed to separate PD signals and disturbances under variable frequency test condition. First, the characteristics of the disturbances from variable frequency test set are analyzed, which illustrates that the pulse disturbances distribute throughout all the phase position of the sine cycle and the amplitudes of the disturbances vary significantly, causing it difficult to suppress the interference by using conventional de-noising method. Then, the basic principle of the pulse separation method based on CFSFDP is introduced. Finally, the effectiveness of the proposed method is verified in laboratory with a pre-defective cable. The laboratory test results show that this method can realize the separation and detection of PD signals in variable frequency resonant test. This method provides a feasible solution for the PD test of power equipment under the condition of variable frequency resonance.