The primary function of insulators is to achieve electrical insulation and mechanical fixation, for which various electrical and mechanical performance requirements are stipulated. For instance, under specified operating voltages, lightning overvoltages, and internal overvoltages, they must not experience breakdown or surface flashover; under specified long-term and short-term mechanical loads, they must not undergo destruction or damage; after long-term operation under specified mechanical, electrical loads, and various environmental conditions, they must not show significant deterioration; the metal fittings of insulators must not produce any noticeable corona discharge under operating voltages to avoid interference with radio or television reception. As insulators are widely used devices, their connecting metal fittings are also required to be interchangeable. Moreover, technical standards for insulators necessitate various electrical, mechanical, physical, and environmental condition tests based on different models and usage conditions to verify their performance and quality.