The no load regulation mode of the distribution transformer in the low voltage distribution network has been unable to meet the voltage regulation needs of the distribution stations. The load regulating distribution transformer can change the high and low side ratio under the load condition, limit the voltage fluctuation to the qualified range, guarantee the continuity of the power supply, improve the quality of the power supply, and greatly reduce the power loss. It has already begun to study and discuss the voltage regulation technology and Application of the medium and low voltage distribution transformers at home and abroad, and the application [1-17 ]. Document [3] according to the composition of transformer tap changer, the load regulating transformer is divided into three types: mechanical improved type, auxiliary coil type and power electronic switch type. The operation principle and development process of typical voltage regulation technology are analyzed and compared. In document [4], a load regulating system based on GPS based distribution transformer with on-line oil filtering function is studied. The composition and characteristics of the system are introduced in order to improve the maintenance free performance of the load regulating device of the distribution transformer, improve the voltage qualification rate and the reliability of the power supply. In document [5], a power electronic loaded voltage regulation scheme is proposed. The main idea is to cancel the traditional mechanical and electric operating mechanism, and use the method of binary code adjustment to realize the load regulation of the distribution transformer without combustible arc type.

The application of load regulating technology promotes the upgrading of the technical performance of the energy saving distribution transformer, and is helpful to the economic and efficient operation of the radio distribution area and the extension and expansion of the function of distribution automation. The combination of load regulation and shunt capacitor switching in distribution transformer has become an important means to realize the integrated automatic control of voltage and reactive power in distribution network and limit the fluctuation of voltage in the range of qualified. It is of great practical significance to ensure the high quality power service and improve the security, reliability and economic operation level of the power distribution network.