Historically, insulators were primarily used on utility poles. With the advancement of technology, they evolved into strings of disc-shaped units suspended from high-voltage transmission towers. These units, typically made of glass or ceramics, are designed to increase creepage distance. Insulators play two fundamental roles in overhead transmission lines: supporting the conductors and preventing current from returning to the ground. These functions must be guaranteed under all environmental and electrical load conditions. An insulator must not fail due to mechanical or electrical stresses; otherwise, the operational life and safety of the entire transmission line will be compromised. 1. Standards for Insulation Resistance The quality...