The Influence of Internal Air Gap on the Electric Field Intensity Distribution Characteristics of Epoxy Resin Insulator on the Roof of High-Speed Train

Epoxy resin insulators are widely used on the roof of high-speed trains. However, epoxy resin materials will produce air gaps during design, pouring and other operations. Air gaps are prone to partial discharge under high pressure, which threatens the safe operation of train-set. In this paper, the epoxy resin insulator on the roof of the train-set is taken as the research object, and the three-dimensional model of the epoxy resin insulator with air gap is made to simulate the electric field environment of 27.5kV on the roof epoxy resin insulator. The change of the maximum electric field intensity on the air gap surface when the air gap span, length and width change, and the influence of the change of air gap parameters on the electric field distribution near it are analyzed. The simulation results show that the change of air gap span, length and width seriously affects the surrounding electric field intensity. During the change of the air gap span, the electric field intensity on the air gap surface gradually increases with the increase of the span. When the air gap size changes, the maximum electric field intensity on the surface is 3.41 times that without defects.

I. Introduction

High-speed trains have developed rapidly due to their advantages of safety, reliability, high speed and strong applicability. The safe and reliable operation of high-speed trains is an important task of its core part train-set. Roof insulator plays an important role in ensuring the safe and reliable operation of train-set. The roof voltage level of high-speed train is relatively low, but there is still a large electric field in the local area with large voltage [1–3], which makes the insulator prone to failure during operation.