Can Different Types of Transformer Oil be Mixed?

Each type of transformer has a fixed transformer oil, a mixed-use will easily cause wrong work.

What are the requirements for the mixed-use of transformer oil of different brands?

In principle, it is not advisable to mix new oil of different grades or running oil of the same quality. If it is necessary to use the mixture, it should be determined whether it is used according to the measured freezing point of the mixed oil.

For foreign imported oil, oils whose sources are unknown and the types of additives contained are not the same, if they need to be mixed with oil of different brands, the aging test of the mixed oil and the mixed oil sample should be carried out first.

The mixing ratio of the oil sample should be consistent with the actual mixing ratio. If the actual use ratio is unknown, use a 1:1 mixing ratio.

Transformer oil: It is a fractionation product of petroleum, and its main components are alkanes, cycloalkane saturated hydrocarbons, aromatic unsaturated hydrocarbons and other compounds. Commonly known as square shed oil, light yellow transparent liquid, relative density 0.895. Freezing point <-45 ℃.

• Transformer oil is a kind of oil for electrical appliances. Its performance mainly includes:
• It must have good electrical insulation performance, high insulation strength, and low dielectric loss.
• The viscosity is small, the heat dissipation is fast, and the cooling performance is good, which can conduct the heat generated by the transformer during operation;
• Good anti-oxidation stability and long service life;
• Low freezing point and good low-temperature fluidity;

The flashpoint is high and the evaporation is small to ensure safe operation at operating temperature (up to about 90°C).

Because it has special performance requirements, other oil types cannot replace transformer oil and must be dedicated. Due to the long-running time of transformer oil, oil replenishment is inevitable, so oil mixing often occurs. At the same time, the oil change after the equipment is overhauled also exists. Therefore, the replenishment and oil change of transformer oil should follow GB/T14542-2000 “Guidelines for Maintenance and Management of Transformer Oil in Operation”, the main points of which are as follows:

1. When the electrical equipment is insufficiently filled with oil and needs to be refilled, the unused transformer oil that meets the relevant new oil standards should be selected first. It is best to add the same oil base, the same brand and the same type of additive oil.

Each characteristic index of the refueling product should not be lower than the oil in Transformer Oil Filtration Machine. When the new oil replenishment amount is small, such as less than 5%, there is usually no problem; but if the replenishment amount of new oil is large, the sludge precipitation test should be done before the replenishment money to confirm that there is no sludge precipitation. Oil replenishment can only be carried out when the acid value and dielectric loss factor are not large.

2. In principle, oil of different oil bases should not be mixed.

Under special circumstances, if you need to mix new oils of different brands, you should determine whether the mixed oil is suitable for the requirements of this region according to the actual measured freezing point of the mixed oil, and then conduct a mixed oil test, and the result of the mixed sample should be no worse than the worst single Poor oil.

If different grades of new oil or used oil are mixed into the running oil, in addition to the solidification point of the mixed oil, an aging test and a sludge test should be carried out, and the sludge precipitation should be observed. Use it without precipitation. The result of the obtained mixed sample should not have to run the oil difference, to determine the mixed-use.

For imported oils or oils of unknown origin and product manufacturers, in principle, they cannot be mixed with oils of different brands. When it is necessary to mix, the aging test of the oil before and after mixing should be carried out in advance, and there is no sludge precipitation. If the quality of the mixed oil should not be lower than the original running oil, it can be mixed and used; if the mixed oil is new, the quality of the mixed oil should not be lower than the worst oil, and it needs to be measured according to the actual The freezing point determines whether it is suitable for use in the area.

When carrying out the mixing test, the mixing ratio of the oil sample should be the same as the actual ratio, if the mixing ratio cannot be determined, the test should be carried out with a 1:1 mass ratio mixing.

3. Precautions for an oil change: The same as the oil replenishment requirements, but the transformer oil should be drained as far as possible to avoid the deterioration of the new oil quality.