Short-duration space charge observation in LDPE at the electric breakdown

It has been known that the electrical breakdown of insulating materials is strongly affected by the formation of space charge in the bulk of materials. Many researchers have attempted to study the relationship between the space charge and the breakdown, however, it has not been clear yet. Although the pulsed electroacoustic (PEA) method has been widely used to observe the space charge profiles, previous work has not show clear evidence of the influence of space charge on breakdown. We have developed a new PEA system with an interval of sub-milliseconds to observe the space charge distribution continuously. Using this system, we observed the space charge dynamics at the breakdown. In this paper we will introduce the space charge behavior of LDPE film throughout the breakdown process.