Transformer Classification

This articles involves about the classification of the transfomer, before we go along let us define first transformer. Transformer is a static device for transforming electrical energy from one alternating current circuit to another without any change in frequency. It changes voltage from high to low and low to high with a corresponding increase or in decrease current. If the voltage increased it is said to be stepped up. If it is decreased, then it is said as stepped down. List below are the classification of transformer.

TRANSFORMER CLASSIFICATION

• According to SIZE
1. DISTRIBUTION TRANSFORMER – Used from transferring power from a primary distribution circuit to a secondary distribution circuit according to SIZE
2. POWER TRANSFORMER – Are used for transferring power from any part of the system between the generator down to the primary distribution system according to SIZE

• According to INSULATION
1. LIQUID- IMMERSED TRANSFORMERS – Are those whose core and coils are immersed in an insulating liquid.
– Liquid can either be mineral or synthetic.
– Liquid should be non-flammable
2. DRY TYPE TRANSFORMERS – Whose core and coils are gaseous or dry compound insulating medium.
– Usually LV and MV systems

• According to LOCATION
1. INDOOR TRANSFORMERS – Is one which because of construction much be protected from weather.
– Usually dry type or non flammable oil immersed type.
2. OUTDOOR TRANSFORMERS – Is of weather resistant construction suitable for service without the additional protection from weather.
– Usually of the mineral oil immersed type.
3. STATION TYPE TRANSFORMERS – Are those designated for installation in a power station or substation.
– Usually at voltages above 34.5kV in any of the windings.
4. UNIT SUBSTATION TRANSFORMER – Is one which is mechanically and electrically and coordinated in the design with, one or more switchgear or motor
control assemblies or combination thereof.
5. CLASSIFICATIONS OF UNIT SUBSTATION TRANSFORMER
1. PRIMARY UNIT SUBSTATION – One with voltage section above 1000V
2. SECONDARY UNIT SUBSTATION – One with voltage section below 1000V.
6. NETWORK TRANSFORMERS – Is designed for use in a vault to feed a variable capacity system in interconnected secondaries

7. PAD MOUNTED TRANSFORMER – Is an outdoor type used as part of an underground distribution system.
– They are mounted on a foundation pad.
8. POLE-TYPE TRANSFORMER – Is one which is suitable for mounting on a pole or similar structure.
9. VAULT TYPE TRANSFORMER – Is constructed so as suitable for occasional submerged operation in water under specified conditions
of time and external pressure