- Radiator in Transformer Definition: A radiator in a transformer is defined as a component that helps cool the transformer by dissipating heat from the transformer oil.
- Heat Generation: When a transformer operates, current through its windings produces heat, increasing the temperature of the transformer oil.
- Importance of Cooling: Controlling the temperature of the oil is crucial to extend the transformer’s capacity and prevent overheating.
- Working Principle: The radiator increases the surface area to dissipate heat, aiding in efficient cooling of the transformer oil.
- Operation and Enhancement: Radiators cycle warm oil from the transformer through their fins to cool it down, and this process can be boosted with fans or oil pumps.
Function of Radiator
When a transformer is loaded, the current starts flowing through it’s windings. Due to this flowing of electric current, heat is produced in the windings, this heat ultimately rises the temperature of transformer oil. We know that the rating of any electrical equipment depends upon its allowable temperature rise limit. Hence, if the temperature rise of the transformer insulating oil is controlled, the capacity or rating of transformer can be extended up to significant range. The radiator of transformer accelerates the cooling rate of transformer. Thus, it plays a vital role in increasing loading capacity of an electrical transformer. This is basic function of radiator of a power transformer.
Oil immersed power transformer is generally provided with detachable pressed sheet radiator with isolating valves. But in case of small size distributing transformer, the radiators are generally integrated parts of transformer body and projected from the main tank. The working principle of radiator is very simple. It just increases the surface area for dissipating heat of the oil. In case of electrical power transformer, due to the transport limitation, this units are sent separately and assembled at site with transformer main body. At the time of dispatching, the flings of radiator are blanketed by gasket and blanketing plates. The radiator valves on the main tank are also blanketed by gasket and blanketing plates.
Assembling and Mounting of Transformer Radiator
Special care is needed when removing radiators from crates and during handling and mounting. Any minor damage can cause oil leaks, as radiator units are made from thin steel sheets for efficient heat conduction. After removal from crates, radiators should be cleaned externally and internally with transformer insulating oil.
Radiator units should be assembled one by one, completing each unit before starting the next. Begin from one side and move to the other. Remove blanketing plates from the top and bottom radiator valves. If the gasket surface is damaged, replace it with a new gasket. Lift the radiator unit vertically and bring it near the main tank valves. Remove the main tank valve blanketing plates, then fit the radiator flange on the respective valve using nuts, bolts, and washers. Assemble all other radiator units in the same manner.
After assembling all the units, this is the time for filling insulating oil. This should also be done one unit by one unit. For that, first the bottom valve is opened and air release plug on the top of the radiator is also gets slowly unscrewed. The oil from main tank will enter into the transformer radiator unit. Air starts escaping from air release plug till the unit is totally filled with transformer insulating oil. The oil filling in the unit is completed when oil comes out from unscrewed air release plug. After that, the air release plug is tightened and top radiator valve is open.
Operation of Transformer Radiator
When the transformer is loaded, warm oil rises to the top of the main tank and enters the radiator through the top valve. It cools down by dissipating heat through the radiator walls and then returns to the main tank through the bottom valve. This cycle continues as long as the transformer is under load. Heat dissipation can be enhanced with fans that blow air over the radiator. If convection alone isn’t enough, an oil pump can speed up oil circulation.
