Three-phase system is widely used in low voltage distribution system in China. Widely used in low voltage distribution network, the power supply of small capacity, point clouds, short radius, this form of power supply can significantly reduce the line loss of low-voltage distribution network. The use of single-phase transformer is to implement an important measure of this power supply, single-phase transformers and single phase transformer, power distribution technology has been listed as China's key recommendation of the power-saving technology. 
 Suzhou City has been 10 years of single-phase power distribution system operation and management experience. The advantages of single-phase power distribution: the promotion of line loss to reduce and improve the voltage quality, the electricity is relatively safe. 
 The technical advantages of a single-phase transformer to the lighting load supply 
 (1) loss of small, energy-saving 
 Single-phase transformer using the same materials of the same capacity than the triple-phase transformer load loss; single-phase transformer enables high voltage lines close to the load point, reducing the low-voltage power supply radius, reducing the loss of low-voltage distribution network. 
 Suzhou * The Village changed to single-phase transformer powered by a three-phase transformer line loss, 50 kVA single-phase transformer with the capacity loss than the three-phase transformer. Using the D12 - 50 single-phase transformer power supply than the use of S11-50 three-phase transformer power supply a year, saving 586 kW. 
 (2) project cost savings 
 Single-phase transformer powered, high-pressure branch line, two lines erection, low voltage line for two or three wire erected; erection of three-phase transformer, high voltage branch line for the three-wire, low voltage line for the four-wire erected. Calculated from the cost of the project, the use of single-phase transformer for power supply, high voltage lines can save 10%, and low voltage lines can save up to 15% of project cost. 
 (3) supply reliability 
 Single-phase transformer power supply for small-capacity dense points, an increase of the number of users, increasing the reliability of the calculation base, improve the reliability of power supply; the same time, the tension load when the power cuts, single-phase transformer will be reduced blackout range, will reduce supply reliability to the user. 
 (4) facilitate the implementation of the new technology of the street lights after midnight Down and Power Saving 
 The city lights are generally two voltage along the road layout in Figure 1 (a) shown in single-phase V / V0 transformer power supply, especially suitable for street light installation and wiring. 
 Regulator (http://www.pandeng.org.cn)