229 / 2018-09-23 15:27:52

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

epoxy resin,Ultra-high Altitude Area,breakdown strength,thickness,penetration

The epoxy resin board has relatively high electrical strength and mechanical strength, it is often used as a kind of insulating material. Many researchers has reported the electrical strength and other kinds of test in the low altitude area. As we all know, the electrical strength is influenced by the air pressure especially for the high altitude area. Few studies have reported the electrical strength of the epoxy resin in the high altitude area. This paper performed the breakdown test of the epoxy resin board at the altitude of 2300m. We built a high voltage test platform in the high altitude area .As the comparison, we performed the air breakdown test at first. We used the electrical methods of the standard GB/T1408.1-2016.In this paper, we prepared the specimens of the epoxy resin board form the epoxy resin manufacturer. In order to obtain the electrical strength, we used two kinds of electrodes, the standard symmetrical cylinder electrode and the standard symmetrical sphere electrode in this paper according to the GB/T1408.1-2016. Before and after every test, we tested the temperature and the humidity. For each test, we repeated three times for the same thickness specimen and we calculated the average breakdown voltage value as the breakdown voltage value of the epoxy resin specimen. In order to get the influence of the thickness of the epoxy resin board for the electrical strength, we used 7 kinds of thickness from the 0.1mm to the 2.0mm. Considering the epoxy resin board may work in the harsh environment such as the wet situation, so in order to obtain the electrical strength of the epoxy resin in the wet situation, we conducted the water penetration test for the epoxy resin board. We used the deionized water to penetrate the specimens. And we tested the mass changes of the epoxy resin board for different penetration hours, then we conducted the breakdown test for the epoxy resin board for different thickness specimens for different penetration hours. To analyze the mechanism of the electrical breakdown of the epoxy resin, we used the microscope to observe the breakdown holes in the epoxy resin board. From these tests, we got the conclusions. The electrical strength of the air in the high altitude is much lower than the air in the low altitude for about 40% in the altitude about 2300m, and the breakdown voltage of the cylinder electrode is higher than the sphere electrode of the air breakdown tests. The breakdown voltage of the epoxy resin board is increasing with the increment of the thickness, but the average electrical strength is decreasing with the increment of the thickness of the epoxy resin board, and the breakdown voltage of the cylinder electrode is also higher than the sphere electrode. After the breakdown tests, we could see a black hole in the specimens, by using the microscope, we could see clearly that the stacked fibers are around the hole and the holes are carbonized. For the thicker board, the trace of the carbonization is clearer. For the water penetration test, the electrical strength of the epoxy board is decreasing with the increasing of the penetration time, and weight of the epoxy board is increasing with the penetration time especially for the thinner board.