The Effects of the Roughness of Interfaces on the Generation and Storage of Charge

Abstract

In this paper, the effects of the roughness of interfaces on the generation and storage of charge between two dielectrics has been investigated. A sandwich structure consisting of two dielectric films of the same nature (crosslink polyethylene XLP1 and XLPE2) was subjected to high DC electric stress for extended periods of time and space charge measurements were taken using the pulsed electroacoustic (PEA) technique. Aluminum and carbon black-loaded polyethylene electrodes were used to investigate the charging behaviour of the electrode/dielectric and dielectric/dielectric interfaces. The time dependence of the space charge distribution was subsequently recorded at room temperature under field (polarization) and short-circuits conditions (depolarization). The experimental results demonstrated that a charge-injected process took place in all cases. However, it was also shown that the sign and the amount of interfacial charge depended drastically on the nature of the interface, the conductivity of the dielectric and the polarity of the electrodes.