Oil Immersed Transformers: Principles, Components, and Benefits

Do you have an idea that the power system would not be complete without the use of transformers? Actually! They assist optimally in the optimal transmission and distribution of power. One of these kinds of transformers is an oil-immersed transformer, which has an advantage over other types in that it can withstand more power and higher temperature settings.

In the following article, we shall discuss the principles, components, types, advantages, and basic maintenance routines of oil-immersed transformers.

1) What is an Oil Immersed Transformer?

“As the name suggests, the transformer is placed in a steel tank filled with insulating oil with moves around to keep it cool via convection but at the same time keep insulating it”

Generally, transformers alter the voltage of alternating current (AC), either raising or lowering it. For transmission purposes over long distances, high voltages are preferred as they facilitate efficient and quick transmission. Lower voltages on the other hand allow safety in the residential, commercial, and industrial sectors.

Power distribution companies use oil-immersed transformers in medium and large ranges due to their durability, efficiency, and good cooling properties.

 

2) Components of Oil Immersed Transformer

To better understand the phenomenon of Oil Immersed Transformers, it is crucial to know each part of the transformer along its role. The following are the major components:

• Core: The core is commonly constructed out of laminated sheets of steel and it is constructed to be the path for the passage of the magnetic flux. It is mostly architectured in such forms as to lower energy losses.

• Windings: Two windings are available in transformers:

• Primary Winding: Has the function of receiving the input voltage.

• Secondary Winding: Connects with the transformed voltage.

Windings are composed of copper or aluminum and are protected from each other by some insulating organ.

• Insulating Oil: The typical insulating oil used is generally mineral oil which serves two purposes cooling and insulation of the interior. This oil is incombustible and it can tolerate high temperatures which makes it ideal for high-power operations.

• Conservator: The conservator is a tank that is situated at the top of the transformer to allow the oil to expand and contract with heat and cooling. It has an oil level and oil pressure drive to control the steady-state ratio within the transformer.

• Breather: Breather contains silica gel and when the transformer oil is heated and expands due to different reasons this gel assists in keeping the moisture out of the transformer hence no contamination is caused and oil life is boosted considerably.

• Radiators: Collecting all trapped heat inside the oil, the radiators are units installed outside of the transformer tank allowing for efficient heat dissipation.

• Bushings: Bushings are insulating fittings that provide connections between high- and low-voltage windings and the external circuit safely.

• Buchholz Relay: This safety device automatically senses gas production as a result of insulation failures and alarms the operators of possible trouble.

3) Working Principle of Oil Immersed Transformer

The Oil Immersed Transformers are used in power distribution areas. These transformers simply work on the principle of electromagnetic induction.

Step 1) Input voltage supplied: An alternating current (AC) passes through the primary winding which surrounds a laminated steel core of the transformer. It causes a magnetic field to be generated.

Step 2) Magnetic flux induction: The generated magnetic field expands and collapses and AC cycles which in turn produces a changing flux in the core. The change in magnetic flux induces a voltage in the secondary winding, which is placed in such a way that it intersects with the magnetic field.

Step 3) Voltage Transformation: The primary and secondary windings have turns in a relative ratio and this determines the amount of voltage that will either step up or step down.

Step 4) Cooling and Insulation: The whole transformer is placed in insulating oil, usually mineral oil, which also acts as a cooling agent. During normal operation of the transformer, oil is used to disperse heat that is generated to prevent any overheating and insulating the windings and the core to avoid electrical breakdown.

Step 5) Output voltage supplied: The secondary winding transfers the voltage to the external circuit. So, the process of voltage adjustment is completed here.

In this way, oil-immersed transformers provide effective and safe means of voltage transformation for the various stages of electricity distribution.

4) Types of Oil-Immersed Transformers

Oil-immersed transformers are classified based on their cooling methods and come in a variety of options:

• Oil Natural Air Natural (ONAN): In this type, the oil and the air surrounding it cool on their own with no fans or pumps needed. It is employed among smaller transformers.

• Oil Natural Air Forced (ONAF): Here, the oil does cool on its own, but the fans cool the radiator by pushing the surrounding air. This arrangement is used in medium-sized transformers.

• Oil Forced Air Forced (OFAF): In this arrangement, the oil and the air surrounding it are both circulated by pumps and fans. This setup is suitable for large-capacity transformers.

• Oil Forced Water Forced (OFWF): This type employs both water and oil in extremely large transformers as cooling mediums so that overheating does not occur when the transformers are under high load.

5) Benefits of Oil Immersed Transformer

The oil-immersed transformers have high regard due to their ability to work under extreme conditions and factors influencing them. Here’s a quick look at the upshots of these transformers that would make them popular with any power management system.

• Cost-Effective: They allow for cheap installation and maintenance and the need for change is minimal since the transformer is robust.

• Reliable and Durable: The transformers can sustain a variety of environmental conditions with low rates of failure which makes them dependable for long periods.

• High Efficiency: Less energy losses, enable oil immersed transformers to perform excellently under heavy loads.

• Efficient Cooling: Oil absorbs dissolves and radiates heat efficiently to avoid overheating of the transformer as well as consistent transformer operation at high loads.

• Enhanced Insulation and Safety: The oil acts as an insulating cover for the windings reducing the risk of electrical discharges and increasing the life span of the transformer.

• Versatile Applications: They can be used for power networks, renewable energy systems, and industrial applications since they come in different sizes and capacities.

• Safety Features: They contain protective devices such as the Buchholz relay which prevents damage by detecting acids. In addition, there is moisture protection which has a silica gel breather.

6) Preventive measures and maintenance of Oil Immersed Transformer

Oil–immersed transformers can operate at optimal levels and last longer due to the regular required maintenance and preventive actions. Some key measures include periodic oil analysis to identify foreign substances and oil conditions, monitoring of oil to avoid its deep frying, and ensuring that the cooling system (radiators and fans) operates optimally.

The breather must be serviced by replacing the silica gel so that moisture does not accumulate, and the transformer must be visually monitored for any oil seepage. Over-temperature conditions that may result in overheating need monitoring, while the Buchholz relay should be regularly checked so that internal fault traces can be found.

Regular examinations for abnormal sound or vibration, coupled with the monitoring of the surroundings, serve to foresee any likely problem in good time. To conclude, irrefutably, electrical examinations, for example, insulation resistance tests are essential for malfunction prevention. The implementation of these actions considerably enhances the dependability and lifetime of the transformer.

7) Conclusion

For any business that needs uninterrupted electricity, oil-immersed transformers are essential. Their unique cooling, insulation, and design features enable them to efficiently cope with a number of functions, making them well-suited for modern power systems. Proper and regular maintenance work, especially preventive maintenance, increases their life span and keeps your operations free of interruptions.

Delixi manufactures state-of-the-art oil-immersed transformers that can withstand harsh conditions and perform at their peak. With Delixi, you get dependability and high technology suited for modern industrial power systems. Let Delixi bolster your power infrastructure.