Distribution transformers in China usually refers to voltage of 35kV and 10kV and below, the following capacity 6300kVA and below electricity directly to end-users of Power Transformer. At present the total line power distribution transformers operating loss of about 41.1 billion kWh, or about  3.16% of 2000 the total generating capacity . Although the distribution transformers are highly efficient equipment (95-99%), but because of its huge amounts of power load and stability, even with a small transformer efficiency improvements can be significant energy savings and reduce greenhouse gas emissions, so the existence of its own huge energy saving potential.

With the development of market economy and science and technology progress, new materials, the continuous application of new technology, new low-loss distribution transformers have been successfully developed. Many domestic transformer manufacturers invested heavily in the introduction of foreign advanced technology and equipment manufacturing, continuous research and development of low-loss transformers and various structural forms of transformer, such as oil-immersed transformer has appeared more energy than new S9 series of S10 and S11 series, the new dry-type transformers SC9 series and amorphous alloy core products such as low-loss distribution transformers in China have shown the energy-saving potential. 

Furthermore, on-line distribution transformer in operation for over 20 years of military age, the old transformers and low efficiency about 10%, and estimated capacity of about 240 million kVA, these transformers is based on six or seven decades on behalf of the standard design of products, loss is very high, if you spend a certain investment to S9 to replace the old transformers will be a great economic benefits. Calculated according to different capacity, the purchase of S9 transformers to replace the old transformers the return on investment generally only 2 to 3 years, its energy-saving potential.