In the selection of the equalizing ring, according to the "Guiding Opinions on Synthetic Insulators" issued by the State Power Corporation, combined with the operating experience in the region and outside, under normal circumstances, products with voltage levels of 110kV and below do not have equalizing rings, 220kV products There is a voltage equalizing ring on the high voltage end, and a voltage equalizing ring on both ends of the 500kV product. Compared with porcelain or glass insulators, synthetic insulators are lighter in weight and windier.
Therefore, in order to improve the lightning resistance level of the selection of synthetic insulators under the premise of satisfying the tower head clearance at the maximum wind deviation of synthetic insulators, the structural height of synthetic insulators of various voltage levels is recommended to be 500kV≥4300mm, 220kV≥2050mm, 110kV≥1280mm, 35kV≥580mm, the corresponding minimum insulation distance is selected according to 500kV≥4100mm, 220kV≥1900mm, 110kV≥1100mm, 35kV≥450mm, the creepage ratio distance should be between 23-25m / MV, it should not be too large, otherwise it will effectively climb Instead, the distance will decrease.
Due to the large and small umbrella structure under the rain condition, the small umbrella is blocked by the large umbrella and has a certain dry area, which is not easy to form a continuous rain surface, and the anti-flashover performance is good. In the ice-covered area, according to the operating experience outside the area, the large and small umbrella structure The composite insulator is not easy to form a continuous conductive water film when melting ice, and the anti-flashover performance is better. Therefore, the size of the composite insulator structure should be an umbrella structure; in the selection of the connection method of the end fittings, the crimping process should be used to reduce dispersion To improve mechanical stability.
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