Guide for the Assessment of Composite Insulators in the Laboratory after their Removal from Service

Composite insulators are a well accepted technology and have been installed since more than forty years in many strategically important transmission lines including HVDC and HVAC. The relevant product standards of IEC and ANSI provide the required technical guidance to develop and manufacture reliable products. However, there is no guiding document available, which can assist in the assessment of aged old or failed composite insulators, in order to evaluate their technical condition. The TB covers the evaluation of longrod type composite insulators and describes methods, philosophies and tools that can be applied for other omposite insulator applications as well.