(1) Power transformer

At present, the representative products that have been in operation in the system include: 1150KV, 1200MV·A, 735-765kV, 800MV·A, 400-500kV, 3-phase 750MV·A or single-phase 550MV·A, 220KV, 3-phase 1300MV·A power transformers; Dc transmission ±500KV, 400MV·A converter transformer. Power transformers are mainly oil-immersed, and the product structure is core type and shell type. Core production accounts for 95%, shell only 5%. There are no overwhelming advantages between the core and the shell, but the core process is relatively simple, so it is adopted by most enterprises; The shell structure and process are more complex, and only traditional factories use it. Shell type is especially suitable for high voltage, large capacity, its insulation, mechanical and heat dissipation have advantages and suitable for the transport of hydropower stations in mountainous areas.

(2) Distribution transformer

The capacity of foreign distribution transformers can reach 2500KV·A, with circular and oval core forms. Circular accounting for the vast majority of the oval due to M0 (core column spacing) small, so the material can be reduced, its corresponding coil is oval. The low pressure coil is wired and foil type, and the tank is provided with a heating pipe (a few) and a corrugated type (most).

(3) Dry transformer

In recent years, dry transformers have been rapidly developed in China, in Beijing, Shanghai and Shenzhen and other big cities, dry transformation has accounted for 50%, and in other large and medium-sized cities has accounted for 20%. There are four types of dry transformation: epoxy cast, filled cast, wrapped and impregnated. At present, Europe and the United States widely use open ventilation type H-type dry transformer, which is a new type of H-type dry transformer developed after absorbing the characteristics of the wrapping structure on the basis of dipping type and using Nomex paper, because of the high price, it has not been promoted in China. At present, the dry distribution transformer with the largest short-circuit test capacity in China is 2500KV·A and 10/0.4KV; The dry power transformer with the largest capacity through the short-circuit test is 16000KV·A and 35/10KV.

(4) amorphous alloy transformer

Although the amorphous alloy transformer has poor short-circuit resistance and large noise, it is energy-saving, so the future development prospect is considerable. At present, China's largest amorphous alloy transformer core production enterprise has an annual core capacity of 3000 ~ 4000t, the production technology of iron core and transformer is not a key factor restricting the promotion of amorphous alloy core gold transformers, and the breakthrough of amorphous alloy strip can contribute to the leap in product quality.

(5) Coil core transformer

At present, the production of coil core transformers is mainly concentrated in the 10KV level, the capacity is generally less than 800KV·A, and 1600KV·A has also been trial-produced, but the power department purchases the majority of the capacity below 315KV·A, which is suitable for rural grid. China has more than 200 coil core transformer production plants, accounting for 20% of a certain scale. China's strong coil core transformer production capacity is about 16 million KV·A, but the actual production is low.