Understanding surface charge accumulation and surface flashover on spacers in compressed gas insulation

TLDR

Surface charges alter the electric field over spacers in compressed gases, potentially triggering catastrophic surface flashover and compromising gas‑insulated equipment stability. The paper reviews literature on surface charge accumulation and flashover on spacers, proposes future research topics, and suggests control methods for improved spacer design. Experimental studies of surface charge accumulation are summarized, identifying new factors affecting transport and measurement, and the correlation with flashover under various voltage pulse waveforms is analyzed.

Abstract

Surface charges have the effect of changing the electric field over spacers in compressed gases, which may affect the stable operation of gas insulated equipment and could possibly trigger a catastrophic surface flashover without warning. In this paper, we review the literature on surface charge accumulation and related surface flashover phenomenon on spacers in compressed gases. A summary of experimental research of surface charge accumulation is presented and, the surface charge accumulation mechanism is also summarized, with some newly identified factors in mind that may affect surface charge transport and measurements thereof. Subsequently, the correlation between surface charge accumulation and the surface flashover phenomenon is thoroughly discussed, and the effect of surface charges on surface breakdown under applied voltage pulses of various waveforms is analyzed. Finally, several important research topics in this area are proposed. In addition, some ideas on potential surface charge control methods are presented to aid the design of a better spacer free from surface charges in future studies.