The primary function of insulators is to achieve electrical insulation and mechanical fixation, for which various electrical and mechanical performance requirements are specified. For instance, under the action of specified operating voltage, lightning overvoltage, and internal overvoltage, there should be no breakdown or surface flashover; under the specified long-term and short-term mechanical loads, no damage or destruction should occur; after long-term operation under specified mechanical, electrical loads, and various environmental conditions, there should be no significant deterioration; the metal fittings of the insulator should not produce any noticeable corona discharge under operating voltage to avoid interference with radio or television reception. Since insulators are widely used, the connecting metal fittings are also required to be interchangeable. Additionally, the technical standards for insulators stipulate that various electrical, mechanical, physical, and environmental condition tests must be conducted on the insulators based on different models and usage conditions to verify their performance and quality.