Guide for the assessment of old Cap & Pin and Long-Rod transmission line insulators made of porcelain or glass: What to and when to replace

Guide for the assessment of old Cap & Pin and Long-Rod transmission line insulators made of porcelain or glass: What to check and when to replace. Based on the results of a series of standard IEC tests carried out on insulators that were in service for periods from 11 to 45 years, a test procedure has been established to determine the state of old insulators and to decide on the safe time for their replacement.