Development of dry-type transformers

Since AEG, a German company, developed the first 400kVA/20kV epoxy cast dry-type transformer in 1964, dry-type transformers have entered a stage of great development. At the same time, the United States has also discovered Nomex insulation paper, which can be used as an insulation material for H-class dry-type transformers. Therefore, there are currently two main types of dry-type transformers: epoxy type and Nomex paper type. [1]
Currently, in developed countries such as the United States, Germany, and Japan, the production of dry-type transformers accounts for over 20% of the distribution transformer production. In complete substations, dry-type transformers account for 80-90%. [2]
The 2013-2017 China Dry Transformer Industry Market Demand Forecast and Investment Strategy Planning Analysis Report shows that China has become the country with the largest dry transformer production and sales volume in the world so far. At present, various high and low voltage electrical products from abroad occupy some important domestic markets, except for dry-type transformers, which have hardly been imported from abroad since the end of the 20th century. In key projects and major projects in China, it is difficult to find traces of foreign dry-type transformers. Under the current organizational construction mode of China's transmission network, the proportion of 10kV dry-type transformers is increasing year by year. [3]
Currently, the pace of urban and rural power grid construction is accelerating, and China's power generation and consumption are increasing day by day. Generally speaking, for every 1 kW increase in power generation, an additional 11 kVA transformer capacity is required; Among them, Satons distribution transformers account for about one-third to half of the total capacity of all transformers. It is estimated that dry-type distribution transformers account for approximately 1/5-1/4 of all distribution transformers. Driven by investment in power grid construction, the transformer industry has a high prosperity, and production will maintain a growth rate of about 20% after 2010. According to historical experience and changes in transformer voltage level structure, the proportion of distribution transformers is around 40%. Calculated based on the 40% proportion, China's new production of dry-type transformers will reach about 200 million KVA.
In China, in 1966, Shenyang Transformer Factory successfully developed the ZSG-1800/10 air-cooled H-class dry-type transformer, while Shanghai Transformer Factory successfully developed the SG3-800/10/1.2/0.4 three coil self cooled H-class dry-type transformer. In the late 1970s, Shanghai Transformer Factory independently designed and developed the SCL-630 epoxy cast transformer. [4] In the past 20 years, with the development of the world economy, dry transformers have achieved rapid development worldwide, especially in distribution transformers. The proportion of dry transformers has been increasing. According to statistics, in developed countries such as Europe and America, it has accounted for 40-50% of distribution transformers. In our country, it accounts for about 50%. In terms of production, since the second urban power grid renovation conference in 1989, China has seen a significant increase in the production of dry-type transformers. Since the 1990s, the annual growth rate has been around 20%, and the total production in 1999 has approached 10000 MVA (which has greatly exceeded the prediction of 4500 MVA 10 years ago) [5]
From the above data, it can be seen that China has become one of the countries with the largest sales volume of dry conversion in the world, with no