According to construction transformer consist of following part-
- Main tank
- Core
- Windings
- Conservator tank
- Breather
- Pressure relief pipe
- Buchholz relay
- Bushings
- Tap Changer
- Radiator
- Header & Footer of the radiator
- Cooling fans
- WTI & OTI
Main tank
It is the main part of the transformer which made of a steel box. The transformer core placed inside the main take. It filled with insulating oil. Its shape is like a cube or, cylindrical that depends on construction.
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| Tank of Transformer |
Core
It consists of laminated silicon steel sheet for all type of transformers to provide a continuous magnetic path and also to provide the minimum air gap. By making core laminated eddy current losses also reduced in the core. Laminations of the core also insulated from each other.
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| Core of Transformer |
Windings
In case of single phase transformer, it has one primary winding and one secondary winding, while in case of three phase transformer it has three primary winding and three secondary winding. It also is known as low voltage winding and high voltage winding that’s depend on which type of transformer, step up or step down.
Low voltage winding is always placed the inner side of the core and High voltage winding is placed above the low voltage winding. Both windings are electrically insulated from each other through the insulation material. There is also a proper distance between two windings for movement of oil.
Both the winding can connect in star or delta with proper phase shift in case of the three-phase transformer.
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| Winding of Transformer |
Conservator tank
This is cylindrical tank which is mounting on the roof of a transformer. The main function of conservator tank provides adequate space for insulating oil during expansion.
When the temperature of the transformer is increased due to any reason than the volume of transformer oil also increased then that condition conservator tank provides adequate space for transformer oil for expansion and act as the reservoir.
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| Conservator Tank |
Breather
Breather is a device which used for Breathing of transformer. When the transformer is loaded then the temperature of transformer increased and the temperature of insulating oil also increased consequently the volume of insulating oil increased. As the volume of transformer oil increased then the air above the oil level in conservator tank out from the breather. When the temperature of insulating oil decreased than that case the volume of insulating oil also decreased which case air to enter into conservator tank.
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| Breather of Transformer |
Pressure relief pipe
It provides protection to transformer from high pressure. Sometimes the high pressure is developed inside a transformer due to decomposition of oil.
Buchholz relay
It is protection device which is used in the transformer. It is connected between main tanks to conservator tank through a pipe. It is used to sense the internal fault of the transformer.
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| Buchholz Relay |
Bushings
Bushings are used to bring the windings out of the tank and also use for insulation.
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| Bushing of Transformer |
Tap Changer
The secondary voltage of transformer depends upon the primary voltage and the load. When the transformer is in loaded condition then the voltage on the secondary terminal decreased and when the transformer is unloaded condition then the voltage on secondary terminal increased. To overcome from the voltage variation tap changer are used.
Radiator
The radiator is used to increases the surface area for dissipating heat of the oil.
When the transformer is under loaded condition, then the current flowing through windings. By flowing of electric current, heat is produced in the windings, the heat produced in winding cause rises of the temperature of the insulating oil. We know that the rating of the electrical machine depends upon the maximum permissible temperature rise limit. The radiator of the transformer is used to accelerates the rate of cooling of the transformer. Thus, the radiator plays a great role in increased loading capability.
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| Radiator of Transformer |
Header & Footer of the radiator
The header is connected between main tank and radiator at upper side and footer is connected between main tank and radiator on the lower side.
Cooling fans
It is used to provide cooling of transformers.
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| Cooling Fan of Transformer |
WTI & OTI
It is used to indicate the winding temperature and oil temperature of the transformer.