| Ultra high voltage grid is the developing direction of the grid. Since the launch of Jindongnan-Nanyang-Jingmen demonstration project, two basin-type insulators have been found with crack defect, but the UHF PD detection failed to warn early. Ultra high voltage basin-type insulator is the core component of Gas insulated switchgear. The safety and reliability of grid are directly affected by their insulation performance. The partial discharge detection method for ultra-high voltage insulator is still not clear. So, it is important to do research on different cracks in ultra-high voltage insulators. The applicability of partial discharge detection method for ultra-high voltage insulator cracks should be checked, and the discharge rules of cracks in basin-type insulator should be studied.In this paper, in order to study the electric field intensity distribution characteristics of UHV basin-type insulator, the finite element analysis model of UHV insulator is established. The electric field intensity of insulators with cracks and without cracks is studied. The maximum, the minimum and the average field intensity of the insulator are all calculated. And the influence of thickness and locations is studied also.In order to carry out experimental study of ultra-high voltage basin-type insulator, the running environment of the insulator is simulated in a252kV GIS, which include the SF6gas concentration, the epoxy resin material, and the voltage grade. The experimental prototype of ultra-high voltage insulator is processioned, and the discharge experiment platform is designed.In order to study the discharge characteristics of cracks, different kinds of crack in the insulator are designed. They are of different kinds of length, location and size. The UHF measurements and current pulse method are used to test the discharge, and the discharge rule of cracks in the insulator is summarized. |
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