The development of distribution transformer in China from th

    The classification of transformer, transformer is by electromagnetic induction, at the same frequency, between two or more windings, the transformation of communication voltage and current and transmission of electrical energy. Its basic principle is: electromagnetic induction principle. According to the voltage class, Chinese transformers can be divided into UHV (1000KV and above) , UHV (330KV and above, 1000KV and below) , 110(66)-220kv transformers, 35KV and below. Distribution transformer usually refers to the power transformer running in the distribution network with voltage level of 6KV-35KV and capacity of 6300KVA or below, which supplies power directly to the end-user. Distribution transformers are widely used in industry, agriculture, urban communities and other end-use energy fields. There are many kinds of distribution transformer. According to the different voltage levels, it is divided into 6KV, 10KV, 20KV and 35KV transformer, according to the different insulation medium, it is divided into oil-immersed transformer and dry-type transformer. Oil-immersed transformer is divided into: A, non-closed type oil-immersed transformer, mainly in industrial and mining enterprises, agriculture and civil buildings widely used; B, closed type oil-immersed transformer, mostly used in the petroleum, chemical industry, oil pollution, c, sealed oil-immersed transformer, can do industrial and mining enterprises, agriculture, civil construction and other occasions for power distribution. Dry-type transformer is divided into: A, sealed coil dry-type transformer, suitable for high-rise buildings, commercial centers, airports, stations, subways, hospitals, factories and other occasions; B, non-sealed Coil dry-type transformer, suitable for high-rise buildings, business Center, airport, station, subway, petrochemical and other occasions. Distribution transformer annual output and guess since 2000, because of urban and rural power grid renovation project pull, China's distribution transformer mall capacity completed a steady growth. Distribution transformer in the proportion of transformers has reached more than 40% . The annual output of distribution transformer also increases year by year (figure 1) . According to the statistics of R, from 2008 to 2015, the annual output of distribution transformer in China is 4846594MVA. In the next few years, power grid construction and urban and rural distribution network transformation is still the primary task of China's power industry. The State Council has decided to carry out a new round of upgrading of the rural power grid. Two-thirds of the funds for the upgrade will be spent on the purchase of power transmission and transformation equipment. The distribution transformer market is expected to maintain a strong momentum of development. Rpredicts that the capacity of distribution transformer in China will also increase steadily. According to statistics, the loss of transmission and distribution accounts for about 6.6% of the national power generation, of which the loss of distribution transformer accounts for 40-50% . In 2013, for example, China's annual power generation was 5.32 trillion kwh, and the power loss of distribution transformers was about 170 billion kwh, equivalent to 1.7 times the annual power generation of the Three Gorges Power Station (about 100 billion kwh) in 2013. With the development of the policy of "energy-saving and consumption-reducing" in China, the state encourages the elimination of high-energy distribution transformers and the popularization of high-efficiency distribution transformers. Some of the high-energy distribution transformers running in the power grid in China are not in line with the industry development trend and are facing the need of upgrading and upgrading. The "distribution transformer energy efficiency improvement plan (2015-2017) " issued by the three ministries and commissions has clearly given an annual plan for the elimination of high energy-consuming distribution transformers. As an important measure of energy conservation and emission reduction, many countries have adopted corresponding policies to enhance the energy efficiency of distribution transformers. In recent years, China also through the implementation of distribution transformer energy efficiency improvement plan to speed up the application of high-efficiency distribution transformer. Many domestic transformer manufacturers have invested a lot of money to introduce advanced manufacturing technologies and equipment from abroad, and have been developing low-loss transformers and transformers of various structural forms, the low loss products such as SCB10 series of dry-type transformer and Amorphous Alloy core show the potential of energy saving of distribution transformer in China.