Description and performance of high voltage synthetic insulators

Abstract

For very high voltage transmission lines, it may be advantageous or even necessary to replace the conventional porcelain or tempered glass insulator strings by lighter non ceramic insulators. Modern composite materials such as resin bonded glass fibers and filled polymers may be used to produce high strength-to-weight ratio insulators. The electrical and mechanical characteristics of these new synthetic insulators have been found satisfactory in short term evaluation. However, the properties of polymeric materials are expected to change with time when subjected to stresses. The initial results of long term uniaxial mechanical tests and of accelerated aging tests indicate no unacceptable degradation with time. Further investigation and in service evaluation are needed to characterize the long term behaviour and/or possibly optimize the design of these high voltage synthetic insulators.