How to Distinguish High, Medium and Low Voltage Transformers

How to Distinguish High, Medium and Low Voltage Transformers

A step-down voltage transformer simply is a type of transformer that reduces a higher level voltage to a lower level. The transformer has the voltage that changes from a lower level to a higher level is a step-up voltage transformer. Therefore, the voltage rating of the primary and secondary voltage plays an important role in deciding the type of transformer.

The voltage transformer has the right voltage transformation, vector group, and turns ratio for a particular application. Both the low and high voltage sides of the transformer install the circuit breaker to ensure transformer protection.

There are 3 types of the voltage transformer as follows:

1, High voltage transformer

2, Medium voltage transformer

3, Low voltage transformer

High Voltage Transformer

There are three types of voltages as follows:

  • High voltage
  • Extra-high voltage
  • Ultra-high voltage

The high voltage transformer is the most appropriate for transmitting power at a longer distance. These are generally step-up type transformers which voltage is step up to reduce the line loss. These types of transformers are applied in the laboratory for testing the equipment. Oil is very important in cooling the high voltage transformer.

According to American National Standard Institute(ANSI), high voltage transformers can handle from 115 to 1100 Kilovolt.

Medium Voltage transformer

The medium voltage transformer is the best choice where we need to transmit a substantial amount of power over a long distance. The voltage is inversely proportional to the current and, thus the current decreases. Thus, the line loss I2R reduces.

According to American National Standard Institute(ANSI),  medium voltage transformers can handle from the minimum of 2.4 kV to the maximum of 69 kilovolts.

Low voltage transformers

Low voltage transformers are appropriate for the rectification of AC voltage into DC voltage. The voltage rating of these transformers is limited. Regarding this type of transformer, electricity converts by transferring current from one set of electric windings to another.

According to American National Standard Institute(ANSI), low voltage transformers have a capacity from 240 volts to 600 volts.

The protection requirement for HV, MV, and low voltage transformers plays an important role. And, the protection scheme should be selected according to electricity rules. For medium and high -voltage transformers special protections like differential protection are a must. The electrical network is protected by differential protection in the case of a fault inside of the transformer.


(+84) 0913.006.538
Skype, Telegram, Wechat ...