Failure Analysis of Fiberglass Insulator Rods.

摘要

Failure analyses were carried out on a group of coated fiberglass-reinforced-plastic insulator rods that had sustained burn damage and loss of coating in service on a radar tower. The investigation included chemical,flammability,electrical and mechanical tests as well as a variety of measurements and inspections. The burn damage,consisting chiefly of carbonaceous tracking and charring,was attributed primarily to the occurrence of electrical discharges,from the energized end fittings to the rods,under conditions in which the electrical leakage path resistances had been reduced by moisture from rain,fog and ocean spray. The effects of this damage on the structural integrity of the rods were evaluated. Recommendations were made for reducing the incidence of such damage in the future,based on the use of skirted insulator rods or more effective coating materials. The principal cause of the coating loss was not positively identified. This form of damage was not found to have serious consequences except as a secondary factor which may have contributed to the occurrence of some partial electrical discharges.