Early fault detection of thin insulation layers in traction battery systems using dc partial discharge diagnostics

Abstract:
Until now, fault detection in the automotive sector has been through leakage current measurement. Using the dc phase-resolved partial discharge (PRPD) diagnostic method, a high level of measurement sensitivity can be achieved. Thus, different failures can be detected, separated, and classified. The investigations presented in this paper concentrate on characteristic failure types, for example, discharges on the surface, which occur in short time spans. In this context, the following findings demonstrate that electrically conductive contacting materials influence partial discharge behavior. This paper shows that it is possible to evaluate the surface quality and provide initial indications for identifying impurities within the insulation. Influences on the partial discharge behavior like polarization, voltage polarity, and ignition delay have also been analyzed. These research results can be used to develop a method for early fault detection of thin insulation layers in traction battery systems.