Aging Characteristics on Epoxy Resin Surface Under Repetitive Microsecond Pulses in Air at Atmospheric Pressure

Abstract

Research on aging characteristics of epoxy resin (EP) under repetitive microsecond pulses is important for the design of insulating materials in high power apparatus. It is because that very fast transient overvoltage always occurs in a power system, which causes flashover and is one of the main factors causing aging effects of EP materials. Therefore, it is essential to obtain a better understanding of the aging effect on an EP surface resulting from flashover. In this work, aging effects on an EP surface were investigated by surface flashover discharge under repetitive microsecond pulses in atmospheric pressure. The investigations of parameters such as the surface micro-morphology and chemical composition of the insulation material under different degrees of aging were conducted with the aid of measurement methods such as atomic force microscopy (AFM), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Results showed that with the accumulation of aging energy on the material surface, the particles formed on the material surface increased both in number and size, leading to the growth of surface roughness and a reduction in the water contact angle; the surface also became more absorbent. Furthermore, in the aging process, the molecular chains of EP on the surface were broken, resulting in oxidation and carbonisation.

Decomposition Characteristics of SF6 under Flashover Discharge on the Epoxy Resin Surface

“…It was reported that with the accumulation of aging energy on the material surface, the particles formed on the material surface were increased both in number and size, leading to the growth of surface roughness; and, the break of the molecular chains of epoxy resin on the surface resulted in oxidation and carbonization [25]. Increased roughness can also result in larger fluctuation of break-down voltages.…”

Deposition of SiCxHyOzthin film on epoxy resin by nanosecond pulsed APPJ for improving the surface insulating performance

“…The shallowing of the trap level and the increasing of surface conductivity resulted in the promotion of surface charge dissipation rate (figures 5 and 6). The higher decay rate of surface charge and the smoother sample surface led to the weakening of distortion of surface electric field distribution, which ultimately suppressed partial discharge and enhanced FV [57,58]. On the other hand, when the Si containing inorganic groups began to grow on the SiC x H y O z thin film surface, the significant increase of surface roughness may be the reasonable excuse for the increasing of trap level depth and then the deterioration of flashover [59,60].…”

Study on Improving Interface Performance of HVDC Composite Insulators by Plasma Etching

“…High-voltage DC composite insulators are mainly composed of internal glass fiber reinforced epoxy resin core bar and external high-temperature vulcanized silicone rubber (SIR) skirt sheath [1,2], the integrated performance of the core bar and sheath interface is directly related to the operational reliability of composite insulators [3][4][5]. Poor interface combination is prone to produce small voids, especially at high temperature, humidity, dirt and other harsh environments, the core rod-sheath samples surface may produce chemical aging due to nitric acid corrosion, oxidative decomposition and hydrolysis, the formation of low-density gas areas, causing local electric field distortion, inducing local discharge, accelerating insulation aging, ultimately leading to the failure of composite insulator insulation [6].…”