The study of the electrical strength of epoxy resin board in the high altitude area

The epoxy resin board has relatively high electrical strength and mechanical strength. Few studies have reported the electrical strength test and data of epoxy resin board insulation material in high altitude. This paper performed the breakdown test of the epoxy resin board at the altitude of 2300m. This paper used two kinds of electrodes, the standard symmetrical cylinder electrode and the standard symmetrical sphere electrode to perform the electrical breakdown test of the air and epoxy resin board insulation material with different thickness. The water penetration test for the epoxy resin board were also conducted. The weight increase percentage and the breakdown test for different penetration hours were also tested. The electrical strength of the air in the high altitude is much lower than the air in the low altitude for about 46% in the altitude about 2300m. The average electrical strength is decreasing with the increase of the thickness of the epoxy resin board. By using the microscope, the breakdown hole and its surroundings can be seen clearly, which are carbonized. For the water penetration test, the electrical strength of the epoxy board decreased with the increasing of the penetration time, and weight gain of the epoxy board increased with the penetration time especially for the thinner board.