Performance of HV transmission line insulators in desert conditions part IV. Study of insulators at a semicoastal site in the eastern region of saudi arabia

An un-energized insulator test station was errected at Dhahran, about 7 km away from the coast in the eastern region of Saudi Arabia. Pollution build-up characteristics of various representative insulator designs were studied and influential meteorological parameters were measured. Using rapid flashover test technique, electrical performance of naturally polluted insulators were assessed through laboratory investigations. The study has revealed that considerably heavy pollution is experienced in Dhahran, exceeding 0.1 mg/cm2 in about ten months of natural exposure. The pollution contains sodium chloride and silica as the major soluble and insoluble ingredients. Insulator bottom surface geometry has a significant effect on pollution build-up while the top surfaces behave almost identically with only a marginal influence in some cases. Prevailing desert meteorology characterized by limited rainfall, has negligible self-cleaning effect on deep-ribbed insulators. Electrical performance assessed using the rapid flashover test technique, gave different order-of-merits based on equal-creepage and equal-height criteria among the tested insulators.