Accumulation of surface charges on the particle contaminated spacer surface in compressed gas under impulse voltage stress

In this paper, the influence of a conducting particle on the surface charging of a solid insulator during the stress with impulse voltages is investigated. The experimental study was carried out using a simplified spacer model with an adhering particle under homogeneous field conditions in SF6 gas and also in different gas mixtures. A specially designed set-up was used to bring about the surface charge data through potential measurement by means of an electrostatic probe. The results show that the particle position, the type of impulse voltage, the type of gas and the gas pressure all combine to explain the accumulation of charges on the spacer surface.