What Is a Dry-Type Transformer and Where Is It Used?

9 May 2023

Dry-type transformers, a type of air-cooled transformer, have become increasingly popular in recent years. Dry-type transformers are characterized by the absence of liquid insulation in their windings and magnetic core. Their versatility has led to a wide range of applications.

Applications of Dry-Type Transformers:

Because they do not pose a risk of explosion, dry-type transformers have a broad range of applications. Some of these applications include:

1. Schools
2. Hospitals
3. Shopping malls
4. Marinas
5. Office buildings
6. Hotels
7. Pump stations
8. Railway systems and dams

Features of Dry-Type Transformers:

1. They are reliable in preventing fires. They have the capability for rapid fire suppression in case of a fire.
2. They can operate without maintenance even in highly humid environments and are resistant to moisture.
3. They maintain safety even in areas with a high concentration of people, provided they are properly maintained.
4. Due to their winding structures, they are resistant to short circuits.
5. The epoxy used in insulation is non-flammable and self-extinguishing.
6. Low-voltage and high-voltage cables are manufactured in a closed environment. They can also be made with cast resin and under vacuum.

Differences Between Oil-Immersed and Dry-Type Transformers:

While oil-immersed and dry-type transformers are different types of transformers, they are often compared. Here are the differences between the two:

1. Dry-type transformers are generally more expensive than oil-immersed transformers due to their lack of explosion risk.
2. Dry-type transformers require less maintenance compared to oil-immersed transformers.
3. Dry-type transformers do not have a risk of causing fires because they lack oil, which is present in oil-immersed transformers.
4. Dry-type transformers can be safely used in areas with a high concentration of people because they do not pose an explosion risk.
5. Dry-type transformers may require additional equipment such as cooling fans. Tap changers and connection groups can be adjusted as needed.

Maintenance of Dry-Type Transformers:

While dry-type transformers require less maintenance compared to other transformer types, periodic maintenance is still essential. Here’s how to prepare for the maintenance of a dry-type transformer:

1. Ensure that the transformer is completely de-energized.
2. To de-energize the transformer, open the circuit breaker at the transformer’s input and disconnect the power supply.
3. After opening the circuit breaker, also open the disconnect switch.
4. All necessary precautions should be taken before performing transformer maintenance.
5. Refer to the user manual and maintenance instructions for the relevant year published by the electricity distribution company (TEDAŞ) before conducting maintenance.