A Study on Simultaneous Measurements of PD Light Emission and Charge in Resin Substrate

In development of next generation high voltage power modules, it is important to ensure high insulation reliability, and for this purpose, it is crucial to evaluate whether or not partial discharge (PD) occurs in the module. PD is generally measured with a sensitivity of 10 pC, for example, is used as a threshold. However, there is a problem that it is unknown on the PD location. In this study, an attempt is made to propose a method for PD location whether from inside and outside the substrate by simultaneously observing PD charge and light emission. As a result, it was found that PD light emission was observed in the insulating substrate without small voids, while that was not in the substrate with voids. The proposed algorithm was found to provide a distinct PD location in the insulation substrate.