Unraveling the “U-Shaped” Dependence of Surface Flashover Performance on the Surface Trap Level

Shengtao Li,Zhen Li,Daomin Min,Yin Huang,Farooq Aslam,Weiwang Wang,Haoming Xu

doi:10.1109/access.2019.2958956

Shengtao Li, Zhen Li + Show 5 more

Open Access

https://doi.org/10.1109/access.2019.2958956

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Abstract

The effects of surface traps on surface flashover remain controversial. To clarify the relation between surface flashover and surface trap level, in this work, the surface trap level of epoxy composites was modified by nanoparticles incorporation, electron beam irradiation, and ozone treatment. Surface trap characteristics were analyzed by surface potential decay. Surface flashover voltages were measured in a vacuum for dc voltage and in SF 6 for ac voltage. The “U-shaped” curve is founded to describe the relation between surface flashover voltage and surface deep trap level, surface flashover voltage first decreases and then increases with surface deep trap level. Enhancement of surface flashover voltage is attributed to reduced surface charge density, which was calculated by a double-trap flashover model. The simulation results indicate that the surface charge density on left side of “U-shaped” curve is controlled by surface shallow traps, whereas that on the right side is determined by surface deep traps. The effects of surface shallow and deep traps on surface charge accumulation and dissipation are used to demonstrate the reduced surface charges and improved surface flashover voltage for the “U-shaped” curve. The proposed “U-shaped” curve offers a promising way to improve surface flashover performance for high-voltage applications by tailoring surface trap characteristics with surface modifications.

Highlights

Epoxy resins (EP) with excellent mechanical and electrical performance are used extensively in advanced spacecraft and extra-high voltage power applications [1]–[5]
Two peaks of the curve are surface shallow and deep traps Horizontal and vertical coordinates of the maximum points are regarded as the surface trap characteristics, that is. surface trap level and density
In this work, the surface trap level of epoxy composites were surface-modified by nanoparticles incorporation, electron beam irradiation, and ozone treatment

Summary

Introduction

Epoxy resins (EP) with excellent mechanical and electrical performance are used extensively in advanced spacecraft and extra-high voltage power applications [1]–[5]. It’s important to improve surface flashover performance for epoxy resin. There are several factors influence surface flashover, such as voltage waveforms, gas species, materials, surface charge, and the shape of insulators and electrodes, etc. Closely linked to surface flashover and have been increasingly studied in recent research [10]–[14]. It is widely acknowledged that charges accumulating on a solid surface distort the local electric field and increase the probability of surface flashover performances [15]. Surface modifications are necessary to reduce surface charges and improve the surface flashover performance of EP

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