Transformer common main accessories and its function introduction

Transformers are a vital part of the power system, and transformer accessories are key components to ensure their safe, efficient and stable operation. These accessories are small in size, but their role should not be underestimated, they play an important role in the transformer's heat dissipation, insulation, pressure regulation, oil level monitoring and fault protection.

The following is a description of the main accessories common to transformers and their functions:

1. Iron Core

The iron core is the magnetic line path of the transformer and an important structural member that supports the windings. It is usually made of laminated silicon steel sheets, which can effectively guide and concentrate the magnetic flux, thus realizing the effective transmission of electric energy.

2. Windings

The winding is the pathway for the current and the key part of the transformer for electromagnetic induction. It is made of twisted wires, and there are high-voltage windings and low-voltage windings, depending on the voltage level and power requirements.

3. Fuel tank (Tank)

The tank is the outer shell of the transformer and is filled with transformer oil. The main function of the tank is to provide insulation and heat dissipation for the transformer while protecting the internal components from the external environment. The oil tank usually also has a number of interfaces for auxiliary accessories integrated into it, such asoil level meter, thermometers, etc.

4. oil pillows (Oil<bos>)

The oil pillow, also known as the oil reservoir, is mounted on top of the fuel tank. It serves two main purposes:

• Adjustment of oil level: When the oil volume expands or contracts due to temperature changes in the transformer, the oil pillow can store or replenish the transformer oil, always keeping the oil level in the tank normal.

• Reduced oil degradation: The oil pillow reduces the contact area of the transformer oil with air, thus slowing down the deterioration of the transformer oil due to oxidation.

5. Tap Changer

Voltage regulators, also known as tap changers, are used to adjust the output voltage by changing the turns ratio of the transformer's high and low voltage windings. This enables the transformer to adapt to different voltage requirements and ensures the stability of the power supply. Voltage regulators are divided into on-load and off-load regulators.

6. Breather

The breather is mounted on the oil pillow and filled with adsorbent (such as silica gel). Its role is in the operation of the transformer, when the oil level in the tank due to temperature changes and increase or decrease, to absorb the moisture into the transformer internal air, to prevent the transformer oil moisture and reduce the insulating properties.

7. Explosion Vent/Pressure Relief Device (EVD)

The explosion-proof tube is a safety protection device. When a serious fault occurs inside the transformer, such as a short circuit or overload, resulting in a sharp rise in internal pressure, the explosion-proof tube will automatically open to release the internal pressure, thus preventing the tank from exploding and protecting the equipment and personnel.

8. Thermometer

Thermometers are used to monitor the internal oil temperature of the transformer. Usually installed on the top of the transformer tank, it can visually display the oil temperature and help operation and maintenance personnel to detect overheating and other abnormalities in a timely manner. Some thermometers also have alarm contacts that can signal when the oil temperature is too high.

9. Bushing

The bushing is an insulating device for the connection of the transformer leads to the outside and is installed on the transformer box cover. It not only ensures the insulation between the leads and the transformer shell (ground), but also plays the role of fixing the leads. According to the voltage level and design requirements, there are various types of bushings, such as porcelain bushings, oil-filled bushings, capacitive bushings and so on.

10. Cooling Device

The cooling device is responsible for radiating the heat generated by the transformer during operation to keep it within a safe operating temperature range. Common cooling methods include natural cooling (radiator), forced oil circulation fan cooling, and forced oil circulation water cooling. Related accessories include radiators, cooling fans, oil pumps, etc.

11. Oil Purifier

Oil purifiers, also known as regeneration devices or filters, rely on internally filled adsorbents (e.g. silica gel, activated alumina, etc.) to absorb water, acids and oxides in the transformer oil and purify the circulating transformer oil, thereby extending the service life of the transformer oil and the overall operating life of the transformer.

12. Oil Drain Valve

The oil drain valve is installed at the bottom of the tank for easy discharge of transformer oil and is usually used during maintenance or replacement of transformer oil.

13. Valve/Butterfly Valve

A flapper or butterfly valve is usually installed between the radiator and the tank to control the circulating flow of transformer oil. When servicing or replacing the radiator, the radiator can be isolated by closing the butterfly valve without draining the entire transformer of oil.

14. Insulating Materials and Sealing Components

These accessories include various insulating sheets, insulating paper, insulating tape, oil-resistant rubber gaskets, O-rings and so on. They are used for insulation between the internal parts of the transformer, as well as the sealing of the oil tank, casing, etc., to prevent the leakage of oil and the entry of external moisture.

15. Protection Devices and Monitoring Equipment

In addition to the ones mentioned above, there are more advanced protection and monitoring devices such asGas Relay(Buchholz Relay), which is mounted on the pipe between the oil pillow and the tank, monitors the generation of gas inside the transformer and sends out an alarm or trip signal in time. There are also pressure-vacuum gauges.

These transformer accessories together constitute the complete functional system of the transformer, and their quality and correct selection is crucial to the reliable operation of the transformer.