Differences in Cooling Methods between Dry-Type Transformers and Oil-Immersed Transformers

Dry-type transformers and oil-Immersed Transformers differ in many aspects due to their distinct structural characteristics. This article focuses on their differences in cooling methods. The following are some key distinctions:

1.Different Cooling Media

Dry-Type Transformers: Use air or gas as the cooling medium. Heat dissipation relies on the natural convection or forced airflow of air.Oil-Immersed Transformers: Use transformer oil (mineral oil or synthetic ester oil) as the cooling medium, leveraging the high thermal capacity and fluidity of oil for heat transfer.

2.Different Types of Cooling Methods

Dry-Type Transformers

Natural Air Cooling (AN): Relies on natural air convection and radiation for heat dissipation. No additional equipment is required, making it suitable for small-capacity or low-load scenarios.

Forced Air Cooling (AF): Uses fans to force airflow, accelerating air movement and improving heat dissipation efficiency. Suitable for large-capacity or high-load scenarios.

Oil-Immersed Transformers

Oil Natural Air Natural (ONAN): Relies on the natural convection of oil. Heat dissipates through the tank surface or cooling fins via natural airflow. Suitable for small transformers.

Oil Natural Air Forced (ONAF): Builds on ONAN by adding fans to enhance heat dissipation efficiency.

Oil Forced Air Forced (OFAF): Uses oil pumps to force oil circulation. The oil is cooled by fans as it passes through radiators. Suitable for large-capacity, high-load transformers.

3.Different Heat Dissipation Principles

Dry-Type Transformers: Heat is transferred from the surface of windings and the core to the air through thermal conduction and convection. The heat dissipation path is relatively short.

Oil-Immersed Transformers: Heat is first transferred to the oil, which then circulates to carry heat to radiators or the tank surface. The heat is then dissipated through air convection. The heat dissipation path is longer but more efficient.

4.Different Application Scenarios

Dry-Type Transformers: Simple cooling methods make them suitable for indoor environments with high requirements for fire safety, environmental protection, or limited space, such as commercial buildings, hospitals, and data centers.Oil-Immersed Transformers: High cooling capacity makes them suitable for large-capacity, high-voltage, and long-term continuous operation scenarios, such as substations, industrial plants, and outdoor power transmission.