Oil Used in Transformers and Maintenance of Transformer Oil

Transformers are considered as one of the most important equipment of the power network as their service in distribution of the generated power is most significant. Therefore, maintenance of such transformers become more responsible as sudden failures in transformer leads to heavy interruptions in power supply. The effective functioning of such transformers depends on the insulation condition of the equipment. The quality of the oil used in transformers (Liquid insulation)  determines the reliable working of the transformer and hence ensures the life of transformer.

Transformer Mineral Oil:

Mineral oil is mostly used as liquid insulation for power transformers due to their high heat transfer aspect also it serves as better coolant due to its high viscosity index. The breakdown voltage of the oil used in transformer should be high as it has to withstand the effects of ageing, thermal stress and stress due to heavy loading etc.  Mineral oil has considerable operating characteristics in this concern. After working continually for years, the mineral oil used in the transformer gets deteriorated by dissolved gases in the oil. Also it develops sludge and acid products due to oxidation process that takes place overtime. This necessitates proper maintenance strategies that should be carried onsite for the effective functioning of such transformers.

Maintenance Of Transformer Oil :

Oil purification removes the Solid impurities from the contaminated transformer oil by transformer oil filtration. It also aims to remove the moisture and dissolved gases developed due to ageing. The oil used in transformer should be purified regularly as a transformer preventive maintenance procedure to improve the quality of the oil.

Transformer Oil Filtration :

To extend the life of transformer the oil used in the transformer has to be  purified  by oil filtration system once in a while . Now a days this can be done onsite by using advanced machines and skilled engineers. To purify the transformer oil high vacuum transformer oil filtration machine is engaged. The oil from the transformer is pumped into the inlet and oil gets prepared for processing without any interruptions.  The temperature of the transformer oil is raised to a particular level by the heaters present in the machine which separates the moisture from the oil. The heaters are controlled to avoid any overheating. Then the oil is made to fed through the respective transformer filtration system vacuum. The sludge material present in the insulating oil is removed by filtering through series of filters present inside the high vacuum oil filtration machine. The last important step is to admit the oil in to the degassing chamber. The chamber is allowed to be at high vacuum where the dissolved gases found in the contaminated transformer oil is processed stage by stage to get purified. A discharging pump is also designed in this chamber through which the degassed oil is taken out.  Now the filtered oil is analyzed for its quality which would be better when compared with the values before oil filtration.

Recycling Transformer Oil

The transformer oil is expected to contain chemical impurities such as polychlorinated biphenyls which will hardly affects the potential of the oil used in the transformer in turn leads to breakdown of the equipment. Recycling Transformer Oil is has become necessary over the years of continuous service. These unwanted chemical impurities can be removed by used oil recycling done by advanced chemical techniques. The oil after gone through purification and recycling serves efficient for another few years there by extending the life span of the transformer.