Some transformer oil purification methods are described in the following sections:
1) Boiling
Oil is heated to the boiling point of water in a device called a boiler. The water in the oil will evaporate because the boiling point of oil is higher than the boiling point of water. This method is the simplest method but has its drawbacks. First only the displaced water from the oil, while the fiber, charcoal and other impurities remain. Both oils can be aging quickly because of the high temperatures and the presence of air.
Deficiencies that can be addressed with a second oil boiler vacuum (vacuum oil boiler). This tool is used by the oil that is heated in air tight vessel (water tight vessel) where the air is moved along with the water that evaporates from the oil. Water boils at a low temperature in a vacuum therefore evaporate more quickly when the oil is boiled in these tools at relatively low temperatures. This tool does not remove dirt on the first constraint, so that impurities remain.
2) Centrifugal Equipment
Water fibers, carbon and heavier mud can be removed from the oil after the oil settles. For this problem requires a long time to speed it up so that the oil is heated to 45-55 ° C and rotated rapidly in a centrifuge apparatus. Impurities will be depressed to the vessel by centrifugal force, while the clean oil will remain at the center of the vessel.
This tool has a high efficiency. Development tool is a vacuum centrifuge. The main part of the drum is a drum with a large number of dishes / plates (up to 50) which is mounted on a vertical shaft and rotating together. Because the plate has spaced one-tenth of a millimeter, these plates carry oil because of friction and reduced weight impurities out.
3) Screening
With this method the oil is filtered through filter paper so that impurities can not pass through the pores of the filter is small, while the dew or moisture absorbed by the paper has a high hygroscopicity. So the filter press is highly efficient transfer of solid impurities and oil vapors from an excess of the centrifugal tool.
Although this method is simpler and easier to do, the output produced less when compared with centrifugal instrument that uses a motor of the same capacity. Filter press is suitable for separating oil in the circuit breaker (CB), which is usually contaminated by soot particles (charcoal) are small and difficult to be separated by using a centrifuge.
4) Regeneration
Aging products can not be moved out of the way before the oil. Screening only to move the remaining part of the sediment in the oil. All properties contaminated oil can be removed with a thorough purification specifically called regeneration. In using absorbent for oil regeneration trasformator often used in substations and power plants.
Absorbent is a substance that the particles can absorb the products of aging and moisture on the surface. The same thing is done in the absorbent filter chamber gas cylinders absorb toxic gases and allow clean air flow. Regeneration of the absorbent can be done more thoroughly when oil mixed with sulfuric acid.
There are two ways of treating the oil with absorbent namely:
」First, the oil can be heated thoroughly mixed with absorbent crushed and then filtered.
」Second, oil is heated may be passed through a thick layer of absorbent called percolation. Absorbents for oil regeneration transformer consists of a cylinder that is welded to the hole where the absorber is basically placed the oil heated (80-100 ° C) to flow upward through the absorber.
When the oil flows up, the filter is clogged by fine particles of the absorber and absorber cleaned air faster and more thoroughly at first. Absorber is used for transformer oil regeneration mostly made of alumina or silica gel and a special kind of clay known as whitening (bleaching earth), clay molding (molding clay).
The transformer should certainly be rested (deenergized) when the oil will be purified or regenerated with one of the above methods, however the above can be implemented in an overloaded if done special treatment. Development of transformer oil regeneration method in a state loaded with filter removal is heating (thermal siphon filter) which is connected to the transformer oil tank. This filter is filled with absorbent as much as 1% of the weight of the transformer oil.