In China's distribution system, three-phase three wire system or three-phase four wire system is usually used in three-phase distribution system, so three-phase transformer is widely used. It is the most critical equipment in the power supply and distribution system. Its function is to increase or decrease the power supply voltage in the power supply and distribution system, so as to facilitate the reasonable transmission, distribution and use of power supply.

As an electrical technician, only by mastering the basic knowledge of three-phase transformer, and being familiar with the structure and classification, nameplates, ratings, circuit system and magnetic circuit system of three-phase transformer, can he use it safely and reliably and make full use of it. Play a role.

Three phase transformer is mainly composed of iron core, winding, oil tank, cooling device and protection device. All cores of three-phase power transformer adopt core structure. Generally, the core of core structure adopts overlapping stacking process. Winding is the circuit part of three-phase power transformer.

The oil tank is composed of the main body, the cover, the radiator and the drain valve. Its main function is to connect the transformer as a whole and heat dissipation. Inside are windings, cores and transformer oil. Transformer oil not only has the function of circulating cooling and heat dissipation, but also has the function of insulation. There is a certain distance between the winding and the box (box wall, box bottom), and the distance is insulated by the oil in the oil tank as the insulating layer.