Polymeric Composite Insulators for Overhead Power Lines. A Review of In-Service Damages and Diagnostic Approaches

Polymeric composite insulators have been used worldwide from decades. Various cases of their failures attracted attention to the disadvantages of the design and to the necessity of tools and methods for diagnostics of their condition and remaining service life. The most important thing for the personal responsible for the maintenance is to have effective tools and knowledge to determine the insulators condition. The paper presents a review of the current experience on the maintenance of polymeric composite insulators and aims to highlight the existing diagnostic methods that are suitable for field inspection. Another purpose of the publication is to outline guidelines for development in the field of in-service diagnostics. The types of damages, the causes and the factors leading to their occurrence are presented. Various methods for diagnostics and assessment of their applicability are considered. The corresponding conclusions have been made.