Parts Of A Transformer and Their Functions
A transformer is an electrical device that transfers electrical energy from one circuit to another by electromagnetic induction (also called transformer action). It is used to step up or step down AC voltage. It is also called an electrostatic device because it doesn’t contain moving parts.
It works on a principle of Faraday’s Laws of Electromagnetic induction. In the transformer, an electrical connection does not occur, but it is magnetically connected.So, It requires and works only the AC voltage source to generate the magnetic flux in the electromagnetic field. And it is playing a significant role as a protective device by regulating (raising or lowering) voltage in an electrical power system.
The transformer has the main function to transform the power from one circuit to another circuit at a constant frequency. In the transformer, power is measured in the KVA rating, not kW.The various types of transformers are used in the power system. This classification of the transformer is classified into a different basis.
Parts of a Transformer: These are the basic parts of a transformer
- Laminated Iron Core
- Winding of the Transformer
- Insulating Material
- Tap Changer
- Transformer Tank
- Oil Conservator Tank
- Buchholz Relay
- Cooling Tube and Radiator
- Explosion Vent
1. Laminated Iron Core
A core of the transformer is made up of iron or silicon steel or ferromagnetic materials.The main function of Core to support the winding and to provide a flux flowing path in the magnetic circuit. The soft iron core which made by the thin metal strips lamination. Each metal strip has thickness near about the o.5mm. In the below figure, you can see the number of metal strips connected to each other with the lamination layer and form a single core.
It provides a low reluctance path and high permeability for the flux in the magnetic circuit. And this lamination of the core helps to reduce the eddy current loss and hysteresis loss.
2.Winding of the Transformer
The transformer winding is consists of several turns of the copper coil. It is wrapped around the limb or core with the lamination. These windings laminated by the insulation coating because it prevents the short circuit condition.The winding of the transformer is separated by the primary side and secondary side.
On the bases of supply two types as.
I. High voltage winding
II. Low voltage winding
3. Insulating Material
In the transformer, insulating materials rely on their voltage rating. Different types of insulating materials are used in the transformer.These insulating materials maybe a transformer oil, insulating paper, wood, the insulating glass material, tap changer insulating coil from grounding, etc.
4. Tap Changer
Tap changer to regulate supply voltage or load and maintain both conditions by changing the variable turn.The tap changer is easily removed the first turn and connect the next turn ratio. Tap changers can occur on the primary side or secondary side.Generally, tap changer use in the high voltage winding side because it reduces load current.
Classification of Tap Changer –
It is classified into two following category,
- No-load tap changer
- On-load tap changer
5. Transformer Tank
The transformer tank is a cylindrically shaped tank. It is made of steel metal with a high thickness. Core and transformer winding is placed in the transformer tank.The transformer tank is needed to store the oil especially mineral oil. This oil provides insulation and cooling to the transformer winding.
6. Oil Conservator Tank
The oil conservator tank looks like a rectangular tank. It stores the extra oil and directly connected with the transformer tank.The oil conservator tank is played an important role in the transformer.The purpose of the conservator tank is to protect the expansion of oil in the main tank of the transformer. The oil is used in the transformer two purposes-
When the oil level reduces due to losses or leakage, the conservator will be delivering oil to the transformer. Thus, It acts as reservoir oil.
Breather is connected with the conservator tank. It is a cylindrical vessel which filled blue color silica gel.They have two purposes -remove the moisture from the air and to have the capacity to absorb the moisture in a transformer. It plays a role to act as the air filter and provide the free moisturizing air to the conservator tank.
8. Buchholz Relay
Buchholz relay is a protective device that is oil and gas-operated the relay. It is connected to the main transformer tank and conservator tank.When the internal fault occurs in the transformer due to leakage flux, insulation core, core connection, breakdown core, etc. by producing excess heat.
This excess heat decomposes oil in the transformer and gas bubbles formed. Gas bubbles flow in the upward direction to the conservator and collected in the relay.Buchholz relay is fault detected by the amount of nature of gas and oil level in a transformer.During several fault conditions, an alarm is alert then this command send to the circuit breaker and isolates the transformer.
The bushing is an insulating device that is made up of porcelain materials. The terminal of the bushing is provided a path of the conductor to the transformer tank.With the help of the terminal, the transformer gives and provides the supply to another system.In the transformer, two types of the bushing are mostly used- high voltage (HV) bushing and low voltage (LV) bushing. Its rely on voltage rating may be a high voltage or low voltage.
In the above figure, you can see the high voltage bushing occurs in large size and low voltage bushing is occure in a small size.
10. Cooling Tube and Radiator
The cooling tube is necessary for maintaining the temperature and circulating cooling oil in the transformer.And the radiator is connected with the transformer tank. It is also made of a number of metal strips or pipes.Both the cooling tube and the radiator provide the same function in a different way. When losses occur in the transformer, heat is produced. This heat absorbs by the cooling tube and radiator in the form of cooling systems.
11. Explosion Vent
The explosion vent is located at the topmost position on the transformer. The conservator tank is directly connected to the explosion tank with the help of a pipe.The main purpose to prevent damage transformer oil tank by expelling boiling oil during an internal fault. And it is necessary to remove heated oil (in the form of gas) in the transformer.This explosion tank use only for emergency purposes. It mostly works when a breather and Buchholz replay will not doing work properly.