In this article we will look at why purification of transformer oil is necessary and what processes in the transformer it affects.
In scientific circles, there was a discussion for a rather long time (and it still continues) regarding the service life of power transformers. Some participants in the dispute argued that the transformer is not advisable to operate longer than the regulatory period. If this condition is violated, the probability of breakdowns and the occurrence of emergency situations increases significantly. And in the case of power transformers, this is very undesirable. Opponents, however, held a different point of view, which is based on the possibility of using transformers longer than the standard period. But only in the case of timely and sufficient maintenance.
Analysis of failures in the operation of power transformers showed that most of them are connected in one way or another with the insulation system. Therefore, it is logical to assume that the service life of transformers is actually determined by the lifetime of their insulating systems. Transformer oil and paper play a leading role in isolating current-carrying parts. Moreover, oil accounts for about 80% of the total electrical strength of the power unit.
The decisive role in combating the products of aging and decay belongs to the restoration of transformer oil. With timely and quality service, the theoretical use of insulating liquids is unlimited.
But with very deep oxidation of transformer oil, the expediency of regeneration should be confirmed by economic calculations, followed by comparison with the cost of the new oil.
In order to extend the service life of a power transformer, it is advisable to use such operations as cleaning and transformer oil recycling.
Preventive measures aim to remove residues of aging from solid insulation and oil until the moment when they cause irreparable damage to the entire insulation system.
Regeneration and cleaning of oil from dirt can be carried out directly at the place of operation of the transformer. The installation of the CMM-P type of the GlobeCore trademark makes it possible to process the insulating liquid even in live transformers.
Oil for regeneration is taken from the bottom of the tank, after which it is heated, filtered and degassed. Passing through the regeneration unit (cartridges filled with Fuller’s sorbent earth), the dielectric fluid gets rid of aging products and acidic components. The recovered oil from the CMM-R installation again goes to the transformer, but this time to the upper part of the tank. Thus, a closed circuit is formed. While the oil is moving, the products of aging are “washed out” from solid insulation and, together with the oil, are removed from the transformer. The process lasts until the condition of the oil does not meet existing standards.