The purpose of a conservator in an oil-filled transformer is to provide a means for accommodating the expansion and contraction of the transformer oil with temperature changes. Transformers generate heat during their operation due to the electrical losses that occur in the core and windings. This heat causes the transformer oil to expand, and as the transformer cools down, the oil contracts.
A conservator is essentially an expansion tank located above the main transformer tank and connected to it. It is partially filled with oil, and its level rises and falls with the volume changes in the transformer oil. The conservator is equipped with a breathing device, typically a silica gel breather, which helps to keep moisture and dust out of the transformer by allowing the air to pass through a desiccant before it enters the conservator.
The primary functions of a conservator in an oil-filled transformer are:
Oil Expansion and Contraction: As the transformer heats up during operation, the oil expands and rises into the conservator, providing additional space for the increased volume. Similarly, when the transformer cools down, the oil contracts, and the conservator supplies oil back into the main tank to maintain a constant oil level.
Preservation of Oil Quality: By allowing the transformer to "breathe" through the silica gel breather, the conservator helps prevent the entry of moisture and dust into the transformer. This helps preserve the quality of the insulating oil, which is crucial for the proper functioning and longevity of the transformer.
Monitoring Oil Level: The level of oil in the conservator provides a visual indication of the transformer's condition. Unusual oil levels can be an early warning sign of potential issues, such as leaks or internal faults.
Overall, the conservator plays a vital role in maintaining the stability and efficiency of oil-filled transformers by accommodating the oil's thermal expansion and contraction and protecting the insulating oil from external contaminants.