Distribution transformer is one of the important industrial and mining enterprises and civil equipment for power distribution systems, it will be 10 (6) kV or 35kV network voltage falls below 230 / 400V bus voltage users. Such products applicable to the exchange 50 (60) Hz, three-phase maximum rated capacity 2500kVA (single-phase maximum rated capacity of 833kVA, is generally not recommended to use a single-phase transformers) may, within households (outside) the use, capacity 315kVA and below can be mounted on the rod, the ambient temperature is not higher than 40 ℃, not lower than -25 ℃, the highest daily average temperature of 30 ℃, the highest annual average temperature of 20 ℃, relative humidity less than 90% (ambient temperature 25 ℃), Altitude not more than 1000m. If inconsistent with the above conditions, according to relevant provisions of GB6450-86, and make appropriate quota adjustments.
Oil-immersed transformers 1000kVA and above, shall be installed outdoor thermometer type signal, and then the distant signal. 800kVA and above should be installed oil-immersed transformer gas relay and pressure protection device, 800kVA transformer oil-immersed according to the following requirements, in consultation with the manufacturer, but also can be equipped with gas relay. Dry-type transformers shall be specified by the manufacturer, the installation of a temperature measuring device, and more generally for the 630kVA transformer installations.
Products classified according to the number of phases to distinguish between single transformer can be divided into three-phase transformers and single phase transformer. In a three-phase power system, the general application of the three-phase transformer, when the oversized transport conditions and subject to the three-phase power system can also be applied consisting of three single-phase transformer transformer group.
According to the number of windings can be divided into two-winding transformer and three-winding transformers. The transformers are usually two-winding transformer, namely on the core has two windings, one for the primary winding, one for the secondary winding. Three-winding transformer larger capacity transformer (5600 kVA or more) to connect the three different voltage power lines. In special circumstances, also applied more windings.
According to the structure in the form of classification, it can be divided into core type transformers and transformer steel. As compared with the winding package in the core periphery core type transformer; as the core periphery was wrapped in winding transformer steel. But both are slightly different in structure, there is no essential difference in principle. Power transformers are all core type.
Insulation and cooling conditions according to points, can be divided into oil-immersed transformers and dry type transformers. In order to strengthen the insulation and cooling conditions, the transformer core and windings are together immersed in a tank filled with transformer oil in. In exceptional cases, such as street lights, mine illumination, but also with dry-type transformers.
In addition, there are a variety of special-purpose special transformers. For example, testing high-voltage transformers, furnace transformers, welding transformers and thyristor circuit with a transformer for measuring instrument voltage transformer and a current transformer.