Heat is one of the most prevalent transformer destroyers. Operation at just 8 degrees Celsius above the transformer’s rated temperature reduces transformer life by half. Internal losses, such as those induced by loads, high ambient temperature, and solar radiation, all contribute to the generation of heat.
As no transformer is truly “perfect,” it will experience some losses, the majority of which will be transformed to heat. If this heat is not effectively dispersed, the extra temperature in the transformer might lead to major issues such as insulation failure. It is self-evident that a cooling system is required for a transformer. It’s critical to understand how your transformers are cooled.
Transformer Cooling Methods:
There are various methods for transformer cooling using air and oil, as listed below.
- Air Natural (AN)
- Air Forced (AF) or Air Blast
- Oil Natural Air Natural (ONAN)
- Oil Natural Air Forced (ONAF)
- Oil Forced Air Forced (OFAF)
- Oil Natural Water Forced (ONWF)
- Oil Forced Water Forced (OFWF)
Air Natural (AN): Without the use of any special devices, natural cooling is achieved through atmospheric circulation. The transformer core and coils are exposed to the air on all sides. This approach is limited to very small units at low voltages of a few kV.
Air Blast (AB): An air blast, directed via trunking and produced by a fan, improves cooling. OB: An air blast over the outside of the tank improves the conditioning of an ON-type.
Oil Natural Air Natural: The vast majority of transformers are oil-immersed with natural cooling, which means that the heat generated by the cores and coils is transferred to the oil, and hence to the tank walls.
Oil Natural Air Forced (ONAF): The heated oil distributes its heat to the transformer tank. The tank is hollow, and air is forced into it to keep the transformer cold.
Oil Forced Air Forced (OFAF): Both oil and air are applied by force to cool a transformer, as the title suggests.
Oil Natural Water Forced (ONAF): The circulation of water in cooling tubes located at the top of the tank but below the oil level cools an oil-immersed.
Oil Forced Water Forced (OFWF): By using an oil pump, hot oil is transported to oil to water heat exchanger, where it is cooled using sowers.