Insulators are devices installed between conductors at different voltages or between conductors and grounding components, capable of withstanding voltage and mechanical stress. There are various types of insulators, each with different shapes. Although the structures and appearances of different types of insulators vary significantly, they are both primarily composed of insulating components and connecting hardware.

Insulators are special insulation components that play a crucial role in overhead transmission lines. In the early years, insulators were predominantly used on utility poles, gradually evolving to have many disk-shaped insulators hanging at one end of tall high-voltage transmission line towers. These are designed to increase the creepage distance, and are typically made of glass or ceramic, hence the name "insulator." Insulators should not fail due to various mechanical and electrical stresses caused by changes in environmental and electrical load conditions, as this would render the insulators ineffective and harm the overall usage and operational lifespan of the entire line.