Discharge Characteristics of Roof Insulators in Strong Wind and Sand Environment: A Review

Abstract

There is frequent sandstorm weather in the northwest of China. Roof insulator is exposed to strong wind and sand environment for a long time. A large amount of sand will be deposited on the surface, resulting in a reduction of insulation strength along the insulator surface and a gap between the sheds. Also, affected by the abrasive action of sand, the roof insulator surface hydrophobicity decreases, which is easy to trigger the insulator flashover, threatening the safety of train operation. For this purpose, this article reviews the sand charging mechanism, sand accumulation characteristics, surface discharge characteristics, air-gap breakdown characteristics, flashover characteristics of the insulator, and the effects of surface abrasion on the insulation performance in wind and sand environment. Based on the train operating conditions, future research directions are proposed to be carried out. First, it is necessary to study the sand accumulation characteristics of roof insulators under multifactor coupling and establish a simulation model that reflects the distribution and content of sand. Secondly, it is necessary to carry out research on the flashover characteristics of real roof insulators and higher speed wind and sand environments, and to build the quantitative relationship between wind speed, sand particle size, sand concentration and the gap breakdown voltage. Finally, a method to evaluate the abrasion state of insulator surfaces needs to be proposed, as well as to explore new materials and structures for roof insulators in strong wind and sand environment.