1. Features (1) the dry-type transformer avoids the danger of fire and explosion of the transformer oil caused by the failure in operation. Because the insulation of dry-type transformer is fire-resistant material, even if the transformer breaks down in operation and causes a fire or has an external fire source, the fire will not be extended. (2) dry-type transformer insulation medium is air, there is no leakage of oil problem dry-type transformer operation and maintenance workload is greatly reduced, or even maintenance-free. (3) the dry-type transformer can be installed in the same room as the switchgear and can share a shell with the switchgear to reduce the installation area. 2. At present, in some developed countries, it has been clearly stipulated that the indoor installation of transformers are not allowed to use oil-immersed transformers. The percentage of dry-type transformer output to distribution transformer is increasing year by year in our country. Especially in some special fields and new energy field dry-type transformer occupies an irreplaceable position, such as marine transformer, frequency conversion phase-shift rectifier transformer, nuclear power transformer, etc. . All over the world, non-enveloped air-insulated dry-type transformers, like resin-insulated dry-type transformers, are developed in parallel, and the demand is about the same. According to statistics, the annual demand of dry-type transformers in China is about 200,000 units, of which 96% are resin-insulated dry-type transformers and 4% are non-enclosed air-insulated dry-type transformers. The technology of non-enveloped air-insulated dry-type transformer is mainly Mora and Reliatran in China, and few manufacturers have been introduced.
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