- Breather Definition: A breather controls the moisture level entering a transformer when oil expands or contracts, using silica gel to absorb moisture.
- Conservator Tank Purpose: A conservator tank provides space for the expansion of transformer oil and acts as an oil reservoir.
- Explosion Vent Function: The explosion vent in a transformer releases excess pressure to prevent damage to the transformer tank.
- Radiator Function: The radiator cools the transformer oil by circulating hot oil through its large surface area and cooling it with forced air.
- Oil Cooling Process: Hot oil from the transformer circulates through the radiator, where it cools before re-entering the main tank, facilitated by valves and forced air from fans.
Different transformer accessories are fitted so the transformer can give a long service life. Those transformer accessories also belong in any study of transformer operation and maintenance.
Breather of Transformer
When the temperature of transformer insulating oil changes, the oil expands or contracts. On a fully loaded transformer that volume change exchanges air with the outside. As the transformer cools, the oil level drops and air is drawn in. That process is called breathing, and the device that manages it is the breather. Silica gel breathers dry the air that enters during those volume changes.
Conservator Tank of a Transformer
The conservator tank is a cylindrical tank on top of the transformer’s main tank. When the transformer is loaded or the ambient temperature rises, oil temperature and volume increase. The Conservator tank of transformer gives that oil room to expand and also acts as an oil reservoir.
Explosion Vent of Transformer
The explosion vent in a transformer prevents tank damage by releasing excess pressure generated inside the transformer.
Construction of Explosion Vent of Transformer
This is a bent pipe with thin aluminium diaphragms at both ends. A wire mesh at the lower end of the explosion vent stops pieces of a ruptured diaphragm from falling into the tank. A wire mesh at the upper end of the vent pipe also protects the upper diaphragm from mechanical damage.
Near the lower end, a small oil-level indicator is fitted. If the lower diaphragm ruptures, transformer oil rises in the vent pipe and shows in the indicator, marking failure of the lower diaphragm. If pressure is still high after the lower diaphragm bursts, the upper diaphragm then bursts and lets oil and gas out of the tank. In that way the explosion vent of a transformer prevents mechanical damage to the transformer tank.
Sometimes the upper portion of the conservator tank is connected to the explosion vent by an equalizer pipe, with or without a valve.
Radiator of Transformer
An oil-immersed transformer is always provided with a radiator. On an electrical power transformer, the radiators are detachable and are transported separately to site. The upper and lower portions of each radiator unit connect to the transformer tank through valves. Those valves stop oil draining when a radiator unit is taken off for cleaning and maintenance.
Operation and Purpose of Radiator in Transformer
When the transformer is loaded, hot oil rises in the main tank and enters the radiator through the upper valve. The radiator’s large surface area cools the oil, which then returns to the transformer through the lower valve. That convectional oil flow continues, and fans can blow extra air over the radiator to cool it faster.
