Dry-type transformers have developed rapidly around the world. The time can be traced back to the mid-to-late 20th century, and it is only half a century ago. With the development of my country's modernization construction, the load of urban and rural power grids continues to increase. Dry-type transformers were widely used in my country in the 1990s.

Rectifier Excitation Transformer

The excitation of power plants has gradually changed from the traditional dynamic excitation generator system to a static transformer rectifier excitation system, and dry-type transformers have gradually replaced the excitation transformers. Its voltage level is 10~22kV, and its single-phase rated capacity is 315~3000kVA. The high voltage in power plants usually adopts isolated-phase (pipeline) closed bus incoming lines, and the phase distance is large, so the excitation transformer usually adopts a single-phase structure. This static rectifier excitation system has been widely used in hydropower stations and is also gradually adopted in newly built and expanded large-scale thermal power plants.

Traction Rectifier Transformer

With the rapid development of urban rail transit, dry-type transformers suitable for urban subways and rail transit have been widely used. The voltage levels are usually: 10kV and 35kV, and the capacities are 800, 2000, 2500, 3300, and 4400kVA. The rectifier pulse numbers include 12-pulse and 24-pulse. The 24-pulse rectifier circuit causes 50% less harmonic pollution to the power grid than the 12-pulse rectifier circuit, eliminating the need for filtering devices.

Domestic subway and light rail projects, such as Beijing, Shanghai, Guangzhou, Shenzhen, Nanjing, Wuhan, Dalian, Changchun, etc., all use domestic traction rectifier transformers, and the operating performance of the trains is very good.

Bridge Rectifier Transformer

The rated capacity is 315~2500kVA, the voltage level is usually 3 or 6kV, each unit has 3~9 windings per phase, and two units can be combined to form an H-bridge rectifier through phase shifting.

Three-phase five-column rectifier transformer

Rated capacity 30~2500kVA, voltage level 10, 35kV, used in a double reverse star rectifier circuit, can cancel the balancing reactor, reduce the impact of voltage regulating current, and reduce the transportation height.

It is suitable for transformers with limited installation space or used in double reverse star rectifier systems.