Space Charge Accumulation Properties in Various Insulating Materials under DC High Electric Field at High Temperature

While many kinds of polymeric materials have been developed for being used at high temperature in various devices, there is a few cases that they are used as an electric insulating material for dc high electric stress. However, according to the development of power electric devices in recent years, the demand of an insulating material which show a good performance even at high temperature more than 100 °C has been increasing. Under such severe condition, especially in HVDC (high voltage DC) systems, the space charge accumulation property must be a key factor to evaluate the performance of them. Therefore, we tried to measure the space charge distributions in many kinds of polymers at high temperature (~ 140°C) under high electric stress (~ 120 kV/mm) using the originally developed PEA (pulsed electroacoustic) system for high temperature measurement. Judging from the results, the obtained data can be available to evaluate the performance of them under such severe condition.