Monitoring the environmental degradation of glass reinforced polyester insulator core rods

An environmental stress chamber was built to investigate the long-term degradation mechanisms of the materials. Within the chamber a number of stresses were applied simultaneously to model glass reinforced plastic insulating rods. The rods were subjected to cantilever mechanical loads and electrical stresses. They were also sprayed with, or immersed in, water as the tests progressed. The temperature of the air surrounding the insulators was also controlled. In this way the stresses which are applied to insulating rods in service were simulated. The environmental stress chamber was linked to a personal computer which monitored and recorded the progression of creep and leakage current. The behavior of silicone modified polyester rods has been examined. The results available to date are presented. The change in the rates of creep with different mechanical loads is discussed. In addition, the uptake of water over prolonged periods has been studied