Dry-type transformer refers to a power transformer in which the core and windings are not immersed in oil, the coil and core are cast together, and are naturally cooled or air-cooled. As a newly emerging power transformation and distribution equipment, it has been widely used in power transmission and transformation systems in factory workshops, high-rise buildings, commercial centers, airports, docks, subways, oil platforms and other places, and can be used together with switch cabinets to form compact complete sets of substations. .
Ⅰ Cooling method of dry type transformer
Dry-type transformer cooling methods are divided into natural air cooling (AN) and forced air cooling (AF). When naturally air-cooled, the transformer can operate continuously for a long time at rated capacity. When forced air cooling is used, the output capacity of the transformer can be increased by 50%. It is suitable for intermittent overload operation or emergency overload operation; because the load loss and impedance voltage increase greatly during overload, it is in a non-economic operating state, so it should not be placed in long-term continuous overload operation.
Ⅱ Types of dry-type transformers
1. Impregnated air insulated dry-type transformer: currently used rarely. The winding wire insulation and insulation structural materials are made of insulation materials with different heat resistance levels according to needs to make Class B, Class F and Class H insulated dry-type transformers.
2. Epoxy resin cast dry-type transformer: The insulating materials used are polyester resin and epoxy resin. At present, cast-insulated dry-type power transformers mostly use epoxy resin.
3. Wrap-insulated dry-type transformer: Wrap-insulated dry-type transformer is also a type of resin insulation, and there are currently few manufacturers.
3. Wrap-insulated dry-type transformer: Wrap-insulated dry-type transformer is also a type of resin insulation, and there are currently few manufacturers.
Ⅲ What are the advantages of dry-type transformers and oil-immersed transformers?
1. Dry-type power transformers can avoid the risk of fire and explosion in transformer oil due to malfunctions during operation. Since the insulation materials of dry-type transformers are all flame-retardant materials, even if the transformer fails during operation and causes a fire or there is an external fire source, the fire will not expand.
2. Dry-type power transformers will not have the problem of oil leakage like oil-immersed transformers, and there will be no problems such as aging of transformer oil. Usually, the workload of operation, maintenance and repair of dry-type power transformers is greatly reduced, and even maintenance-free is possible.
3. Dry-type power transformers are generally indoor devices. They can also be made into outdoor devices for places with special requirements. They can be installed in the same room as the switch cabinet to reduce the installation area.
4. Because dry-type power transformers are oil-free, they have few accessories. There are no oil conservator, safety airway, a large number of valves and other components, and there are no sealing and other problems.