Non-Ceramic insulators-a simple design that requires careful analysis

Today, after continued development and extensive field and laboratory testing, nonceramic insulators are in use through 765 kV. At transmission voltages, nonceramic insulators have become very popular from 69 through 345 kV. Above 345 kV some nonceramic insulators are in use; however, their usage has not yet become significant. At distribution voltages, confidence in nonceramic insulators is high, so much so that many utilities purchase only nonceramic type insulators. In other utility owned and operated equipment (transformers and their bushings, potheads, surge protective devices, etc.) it is safe to say that the industry has rapidly converted from porcelain to nonceramic wherever the opportunity has presented itself.