Dry type transformer (the transformer with ring oxygen resin insulation) is mainly used in places with high fire protection requirements. Such as high-rise buildings, airports, oil depots and so on.
Epoxy refers to the insulation of the transformer according to the characteristics of the manufacturing process can be divided into epoxy quartz sand mixture vacuum casting type, epoxy non-alkali glass fiber reinforced vacuum pressure-casting type, non-alkali glass fiber wrapped impregnated type.
① Epoxy quartz sand mixture vacuum casting insulation
This type of transformer quartz sand is filled with epoxy resin, impregnated with insulating paint wrapped around the coil, release coil casting mold, and then under vacuum and epoxy sand mixture of quartz sand drip irrigation pouring. As the casting process is difficult to meet the quality requirements, such as residual bubbles, mixed local uneven and may lead to local thermal stress cracking, so that the insulation of the transformer should not be used in hot and humid environment and load changes in the larger area.
② Epoxy alkali free glass fiber reinforced vacuum pressure differential pouring insulation
The reinforcement of the epoxy alkali free glass fiber is to use the alkali free glass fiber glass felt as the outer insulating layer of the winding interlayer insulation. The outer insulation thickness of the outer layer is usually 1 ~ 3M thin insulation, and the epoxy resin castable mixture is mixed, and the bubble is removed under high vacuum. Because the winding insulation thickness of thin, when impregnated bad forms easily when the partial discharge, so mixed castable to complete, vacuum degassing thoroughly, and a good grasp of the castable with low viscosity and casting speed, to ensure high quality package on the line in the process of casting impregnation.
③ Impregnating insulation of alkali free glass fiber
A transformer impregnated with a alkali free glass fiber is used to complete the coil interlayer insulation treatment and coils impregnated while winding the coil of the transformer. It does not need the above two ways to impregnate the winding molding die, but requires the resin viscosity is small. During the online winding and impregnation process, the resin should not be left with tiny bubbles.
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