Transformer oil serves as the main dielectric liquid insulation in oil-filled equipment. Among other things things, it is used to increase the dielectric strength of the solid insulation. Additionally, in power transformers oil is used to cool and transfer heat, and in high voltage breakers, to quench an unwanted or unsafe arc of electricity.
The general condition of oil, and some index values, may indicate if there are some system defects. When servicing, oil is exposed to such negative impacts as high temperature, moisture, and contact with atmospheric air. As a result, dielectric fluid attracts and holds unwanted contaminants. The performance characterists decline and the oil slowly loses its ability to perform its functions. Additionally, products of transformer oil aging get into the solid cellulose insulation degrading its condition and ability to insulate. In general, some irreversible processes that happen to the solid insulation may result in premature transformer failure.
Beginning in the 1970s, used oil has usually just been removed and replaced with new oil. Such an approach however, is now considered to be higly inefficient due to the high cost of new oil, the labor cost associated with the process and because there is always some used oil left in transformer that will contaminate the new oil. The used oil gets into the new oil and degrades its performance characteristics. Additionally, the used oil that remains in the solid insulation continues the degradation process of the kraft insulating paper.
Today, oil reclamation is considered to be a reasonable and cost efffective solution to this problem since it restores oil to its original condition and removes the contaminated oil from the core and solid insulation. If timely performed, oil regeneration will prevent damage done to solid insulation by aggrissive used oil. This will reduce operating costs since there will be a reduced need to new fresh oil and the cost of disposing of used will have been eliminated. The GlobeCore Process of oil regeneration greatly increases the service life of the dielectric oil and the transformer.
And this is no great surprise since the majority of oil-filled equipment failure are caused by defects in the liquid and solid insulation.
There are several methods of transformer oil reclamation that include:
- zeolite purification;
- filter press purification; and
- centrifuge cleaning and drying (purification, clarification methods)
Zeolite purification is based on mass transfer. As a whole, it is a very difficult process that includes a wide range of subprocesses:
- Absorption (gas is absorbed by a liquid or solid substance);
- Adsorption (the components of the substance are absorbed into the surface of the solid substance);
- Crystallization (substance turns into solid state)
- Dissolution (process that is reverse to crystallization);
- Fractionation (separation of mixtures by repeated component exchange between liquid and gaseous phases, usually moving in counterflow to each other)
- Drying (moisture is removed from the substance); and
- Extraction (substances, dissolved in a liquid, are extracted by another liquid which is not or partially mixed with the first one.
Often, it is the adsorption that is used to regenerate transformer oil. Today, it is considered to be very effective since no sophisticated equipment is required to perform this process. The process consists in oil being passed through a layer of sorbent. Moisture, dissolved in insulating liquid is retained on the surface of the sorbent material. Other substances that have higher adsorption capacity may also serve as sorbents. Adsorbent does not have any impact on the hydrocarbon composition of the oil and allows for the properties of the insulating liquid to be preserved.
GlobeCore has many years of experience in developing, manufacturing and promoting regeneration equipment for transformer oil, industrial oil, turbine oil, transmission fluids and other types of industral and commercial oils. GlobeCore has applied several classical approaches for oil treatment, as well as successfully introducing its own developments due to its experienced engineering staff and knowledge of the world wide market needs.
One of the latest GlobeCore developments is transformer oil reclamation, based on an automatic Fuller’s Earth reactivation system that eliminates hzardous waste and greatly reduces labor demand to complete the processing. First, it provides for considerable cost savings. Second, application of such technology contributes to environment preservation and protection.
GlobeCore advanced oil processing equipment operate on energized transformers thereby eliminating the need for an alternative energy source when conducting preventive maintenance. GlobeCore oil processing equipment is able to restore transformer oil to its original new like condition and greatly extend the service life of your electric power transformers.
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