Effect of External Defects on Partial Discharge Characteristics of High Voltage Stator Insulation

Generator stators components is an urgent issue because the reliability of the stator main component that supplies the voltage. One of the preventive maintenance processes for preventing failure in the stator is to conduct a Partial Discharge (PD) test. In this study, the characteristics of the insulation resistance and external PD of a test stator with a rating of 6.6 kV were studied. The test stator consisted of a full stator and a stator bar cut from a set of phase-to-phase stators. The insulation resistance and external PD tested in the form of surface discharge, corona discharge, and slot discharge are differentiated by the conditioning damage to the stator. The test is performed the PD detection process uses a high-frequency current transformer and is acquired with a digital Oscilloscope and Matlab. The oscilloscope data were processed into PRPD patterns using MATLAB to analyze the PD distribution in each phase and the PD magnitude of each damage. The results of this study can serve as a reference for the design of PD testing procedures on the stator and for the initial identification of the cause of generator stator damage.