Modern industrial enterprises widely use electric power as energy. Electric energy is directly converted from the generators of hydropower stations and power plants. The electricity generated by the generator will be sent out according to different voltage levels according to the transmission distance, so it needs a special device to change the voltage, which is called "transformer".

Transformer is one of the most important electrical equipment in power system. It can change the voltage from bottom to high or from high to low. According to the basic knowledge of electricians, when the agreed power is transmitted, the power loss is inversely proportional to the quadratic power of the voltage, and the voltage loss is directly proportional to the voltage, that is, the higher the voltage, the smaller the power loss and voltage loss consumed on the transmission line. Therefore, in order to reduce the power loss and voltage loss on the transmission line, the voltage must be increased by transformer. In addition, high voltage power can not be directly applied after it is sent to the power consumption area, because the voltage of general electrical equipment is 220 V or 380 V, and some large motors are 3KV or 6kV. Therefore, in order to meet the needs of the application of electrical equipment, it is necessary to use the transformer to change the high voltage into the low voltage required by the user. In power system, the ratio of installed capacity of generator to total capacity of transformer is about 1:6. Therefore, the role of transformer in power system is very important.

Transformer plays an important role in power transmission and distribution system

Therefore, it is required to run safely and reliably. When the transformer is damaged in operation, it will cause power failure. In addition to the application of transformer in power system, transformer is also widely used in other aspects. For example, electric furnace transformer for smelting, rectifier transformer for electrolysis or chemical industry, explosion-proof transformer, mine transformer, electric locomotive transformer, marine transformer, etc. shall be provided as required.

In practical work, the transformer is used to transform not only AC voltage, but also AC current (such as current transformer). Large current generator, etc.), changing impedance, changing phase, etc.