Contents I. Introduction
Gas-insulated switchgear (GIS) has been widely used in power systems due to its high reliability, small footprint and low environmental impact, and has become a key equipment for the large-scale utilization of new energy sources and the improvement of the grid's resistance to natural disasters [1]. The insulation rod is a key component in the GIS, responsible for providing the kinetic power transmission for the opening and closing actions [2]. During the opening and closing of a breaker, the insulating rod is subjected to an operational overvoltage. The insulating properties of the insulating rods face great challenges. The insulation rod used in GIS circuit breakers are often made of fiber/epoxy resins composites. The commonly used fiber materials are glass fiber, aramid fiber and polyester fiber. These fiber materials have high mechanical strength, good insulation performance, and good heat resistance. [3]. However, the degradation of fiber/epoxy resins can lead to insulation failure, the most common of which is the electrical tree degradation, as shown in Fig. 1. Therefore, the electrical tree properties of fiber/epoxy resins are of great practical significance to study the breakdown of composites under strong electric fields.
Breakdown accidents of insulation rods.
