Surface Flashover Studies of Dielectric Polymer Nanocomposites under KHz Unipolar Pulsed Fields in Partial Vacuum Environment

Abstract

Insulating materials play a significant role in high voltage power systems. In general, the high performance electrical insulation materials and structures must be free from unwanted and unpredictable dielectric breakdown through the insulator as well as over the surface. Over the years, surface flashover in partial vacuum conditions under repetitive pulsed or ac applied fields became important for aerospace applications. Furthermore, new nanodielectric materials are also being considered as insulating media for many applications. This thesis presents the studies of the surface flashover characteristics of nano-composites at partial pressure. The nano-composite samples used in the experiments are prepared using electrically insulating two-part epoxy filled with 2%, 6%, and 15% Al2O3 and TiO2 particles. Different substrates are used to cast the nanodielectric and the performances of nanodielectric composites are studied. The plasma characteristics under DC and unipolar signal, such as voltage of breakdown events are collected and analyzed; breakdown characteristics under changing frequency and duty cycle are also studied.