Basic knowledge of distribution equipment

distribution transformer 

Power transformer is to convert the AC voltage of a certain voltage level into another or several levels of AC voltage with the same frequency. When the primary winding is connected with AC, alternating magnetic flux is generated. The alternating magnetic flux induces AC electromotive force in the secondary winding through the magnetic conduction of the iron core. The secondary induced electromotive force is related to the number of turns of the primary and secondary windings, that is, the voltage is directly proportional to the number of turns. The main function of power transformer is to transmit electric energy. Therefore, the rated capacity is its main parameter. Rated capacity is a customary value of power, which represents the size of transmitted electric energy, expressed in KVA or MVA.

According to the function, it can be divided into: step-up transformer and step-down transformer;

It is divided into single-phase transformer and three-phase transformer according to the number of phases;

According to the number of windings: there are double winding transformers (double winding transformers when one voltage changes to another voltage), three winding transformers (three winding transformers when one voltage changes to two voltages) and multi winding transformers;

According to the voltage regulation mode, it can be divided into two types: non excitation voltage regulation transformer and on load voltage regulation transformer.

The distribution transformer in the power system belongs to step-down transformer, which is generally of double winding, oil immersed and self cooling structure, and mostly adopts non excitation voltage regulation. It is usually installed on the tower or in the distribution station, which can generally reduce the voltage from 10kV (20kV) to about 220 / 380V for input to users. Dry type transformers and oil immersed transformers cooled by oil are mainly used in distribution equipment. (the distribution substation (public distribution substation) is mainly dry-type transformer, and the suspender on the tower is oil immersed transformer).