Influence of gas flow on surface charge distribution in partial discharge sequences

Summary

In the outdoor insulators utilized for high-way express train, air flow is an unavoidable factor to influence partial discharge behaviour. In this report, the dynamic surface charge distribution and discharge characteristics in air and nitrogen at different flow velocity were measured by the surface charge measurement system based on Pockels effect. In nitrogen, the surface charge sports become more uniform and the surface charge quantity decreases with the increase of flow velocity. The air flow in a certain flow velocity range can also enhance the uniformity of partial discharge. Unlike nitrogen, the discharge current number and the discharge quantity in air decrease first and then increase with the increase of gas flow. The result in nitrogen agrees with the model suggesting that gas flow increases the density and lifetime of metastable particles and the speed of molecular, thus increasing the diffusion of surface charge. The inception voltage in air increases with the flow velocity, leading to a difference in surface charge distribution and discharge quantity from nitrogen. The differences of surface charge behaviour between air and nitrogen are discussed.

Additional informations

Authors

K. WU, Y. MENG, N. KINSHT, Z. XU

Keywords

surface charge, gas flow, partial discharge, surface charge density