Investigations on breakdown voltage of solid barrier under non-uniform electric field simulation and experiment

This paper presents the breakdown voltage characteristics of a non-uniform electric field affected by the insertion of solid dielectric barrier under air atmosphere. The investigations have been done experimentally and simulated in order to study the surface breakdown phenomenon of solid dielectric barrier. According to the experiments, the results are divided into two parts. The first part is the pressure and the polarity effects on breakdown voltage. The results show the breakdown voltage increase when air pressure are increase and the intersection between the positive and negative DC breakdown curves at the pressure of 1.5 bars, which is supposed to be critical pressure. At the pressure lower than 1.5 bars, the negative DC breakdown voltage is lower than the positive case. In the other hand, the negative DC breakdown voltage is higher than the positive case at the pressure higher than 1.5 bars. The second part is the simulation results of electric field distribution with solid dielectric barrier, which is numerically analysed by Finite Element Method (FEM). It can be described that in case of the thicker solid barrier, the electric field stress at the contact point is lower than the one with thinner barrier. That means the higher applied voltage will be needed to increase the ionization process. Therefore for the thicker solid barrier, the higher voltage must be applied to raise the electric field strength at the contact point to reach the breakdown condition.