The Ability of Dry Transformer to Withstand Short Circuit and the Overall Mechanical Strength of the Coil
Due to the good flow performance of epoxy resin at a certain temperature, a complete rigid body will be formed by pouring and curing the coils in the mold with advanced pouring process. No matter to the axial and transverse electric power and the strong tolerance to the sudden short circuit, there is no cushion in the structure, so the wire will not bear the bending stress. According to the introduction of the national transformer inspection center, there are few examples of the damage of the epoxy cast dry type transformer due to the intolerable short circuit test. Therefore, it can be considered that the high mechanical strength is the biggest advantage of the epoxy casting type dry type transformer.
For NOMEX paper insulating and lacquer type dry type transformer, the NOMEXX paper has very good compressive strength, the deformation is very small and the flexibility is very good under the pressure, and the paint is impregnated under the vacuum pressure, and the drying and curing treatment will not leave any traces on the surface of the nail. But the dren type dry type transformer uses the same cake coil with the same structure of the oil immersed transformer, the cake coil is supported by the cushion block, and the low voltage wire and the core are supported by the bracing. From the perspective of transformer structure, its overall mechanical strength and short circuit withstand capacity are inferior to that of epoxy casting type dry type transformers.