What are the model specifications of distribution transformers?

Distribution transformer , abbreviated as “distribution transformer”, refers to a static electrical device in the distribution system that transforms AC voltage and current according to the law of electromagnetic induction to transmit AC electrical energy. In some regions, power transformers with voltage levels below 35 kV (mostly 10 kV and below) are called “distribution transformers”, abbreviated as “distribution transformers”. The place where a “distribution transformer” is installed is a substation.

A distribution transformer is a static electrical device used in the distribution system to transform AC voltage and current according to the law of electromagnetic induction to transmit AC electrical energy. In China, transformer products are generally classified by voltage level into ultra-high voltage (750 kV and above), extra-high voltage (500 kV) transformers, 220-110 kV transformers, and 35 kV and below transformers. Distribution transformers usually refer to power transformers operating in the distribution network with a voltage level of 10-35 kV and a capacity of 6300 kVA or less, directly supplying power to end users.

A distribution power transformer is a static electrical device used to convert a certain value of AC voltage (current) into another or several different values of AC voltage (current) with the same frequency. When the primary winding is supplied with AC current, an alternating magnetic flux is generated. The alternating magnetic flux, through the magnetic conduction of the iron core, induces an AC electromotive force in the secondary winding.

The magnitude of the secondary induced electromotive force is related to the number of turns in the primary and secondary windings, that is, the voltage is directly proportional to the number of turns. Its main function is to transmit electrical energy, so the rated capacity is its main parameter. The rated capacity is a conventional value representing power, which characterizes the size of the transmitted electrical energy and is expressed in kVA or MVA.

When the rated voltage is applied to the transformer, the rated current is determined based on it under specified conditions without exceeding the temperature rise limit. The most energy-efficient power transformer is the amorphous alloy core distribution transformer, whose main advantage is its extremely low no-load loss. Ensuring the no-load loss value is the core issue to be considered throughout the design process .

When arranging the product structure, in addition to ensuring that the amorphous alloy core is not subjected to external forces, the characteristic parameters of the amorphous alloy must also be accurately and reasonably selected during calculation. Major domestic manufacturers of power transformers include TBEA, Shandong Mingda, and TBEA Luming Transformer, etc.

Distribution transformers are classified into oil-immersed transformers and dry-type transformers based on different insulation media; and into off-load tap-changing transformers and on-load tap-changing transformers based on different voltage regulation methods .

1. Oil-immersed transformers are classified by shell type as:

1) Non-enclosed oil-immersed transformers: mainly include S8, S9, S10 and other series products, widely used in industrial and mining enterprises, agriculture, and civil buildings.

2) Enclosed oil-immersed transformers: mainly include S9, S9-M, S10-M and other series products, mostly used in places with a lot of oil and chemical substances in the petroleum and chemical industries.

3) Sealed oil-immersed transformers: mainly include BS9, S9-, S10-, S11-MR, SH, SH12-M and other series products, suitable for various places such as industrial and mining enterprises, agriculture, and civil buildings for distribution.

2. Dry-type transformers are classified by insulation medium as:

1) Encapsulated coil dry-type transformers: mainly include SCB8, SC(B)9, SC(B)10, SCR-10 and other series products, suitable for high-rise buildings, commercial centers, airports, stations, subways, hospitals, factories, etc.

2) Non-encapsulated coil dry-type transformers: mainly include SG10 and other series products, suitable for high-rise buildings, commercial centers, airports, stations, subways, petrochemicals, etc.