Transformer oil is used in transformers as well as on other oil-filled electrical equipment. These include insulating bushings, circuit breakers, disconnect switches, tap changers, and transformers and reactors.

Insulation function

In electrical equipment, transformer oil can be different potential (potential) of the charged part of the isolation, so that it does not form a short circuit. Because the dielectric constant of air is 1.0, and the dielectric constant of transformer oil is 2.25, the insulating strength of oil is much greater than that of air. Assuming, for example, that the coils of a transformer are exposed to air, they will soon be punctured when the equipment is in operation, whereas a transformer oil filled between the coils of the transformer increases the dielectric strength so that they will not be punctured, and as the quality of the transformer oil improves, the greater the factor of safety of the equipment.

So the transformer oil has a reliable insulation properties, is one of its main functions.

Heat dissipation cooling function

Transformer in the process of charged operation, due to the coil has resistance, the core has magnetic corrosion and eddy current loss, when the current through, it is bound to heat like other electrical appliances. If this heat inside the coil is not emitted, it will inevitably make the coil and the core accumulate more and more heat, thus making the core and the coil internal temperature rises sharply, damaging the solid fiber insulation of the coil external wrapping, so as to burn the coil. If the use of transformer oil as a cooling medium, then this part of the heat generated inside the coil, first of all, is absorbed by the oil, and then through the circulation of the oil so that the heat is emitted, and will not produce heat accumulation inside the coil, thus ensuring the safe operation of the equipment. Absorbed heat transformer oil cooling method has natural circulation cooling, natural wind cooling, forced oil circulation water cooling and so on. General large-capacity power transformer most of the forced oil circulation cooling method.

So heat dissipation cooling is the second major function of transformer oil.

Arc extinguishing function

In the switchgear, transformer oil mainly plays the role of arc extinguishing. When the oil-immersed switch cuts off the electric load, its fixed contacts and sliding contacts will produce an arc between the arc temperature is very high, and with the size of the breaking current and different. If no attempt is made to remove the heat from the arc column and cool the contacts, then after the initial arc, successive arcs will be generated, which can easily cause the equipment to burn out, as well as causing overvoltage and damage to the equipment.

When an oil-immersed switch is initially opened by an arc, the high temperature of the arc causes the oil to undergo intense thermal cracking, and about 70% of the cracking product is hydrogen. As the thermal conductivity of hydrogen is large, hydrogen can absorb a large amount of heat, and this heat will be conducted to the oil, and the switch contacts directly cooled, so as to achieve the purpose of arc extinguishing.

So the arc extinguishing effect of transformer oil is the third major function.

The protection function of the insulating material

As the viscosity of the transformer oil is relatively low, so the volatility is good, it can be easily filled to the insulation gap, so can play a role in protecting the core and coil components. As the oil fills the voids in the insulation, it minimizes the content of these voids. That is to say, the oil will make the oxygen mixed into the equipment first oxidizing effect, thus slowing down the erosion of oxygen on the insulation material.

To summarize, transformer oil in the transformer, reactor, transformer and casing mainly play the role of insulation and heat dissipation cooling, but if there is an arc in the above equipment, can also play the role of arc extinguishing, in the oil switch mainly play the role of arc extinguishing and insulation.

Haikun Petrochemical Technology Co., Ltd. specializes in providing high-quality and efficient transformer oils

I-10℃ transformer oil (general purpose) I-10℃ transformer oil (naphthenic)

I-20 ℃ transformer oil (special) I-20 ℃ transformer oil (naphthenic)

I-30 ℃ transformer oil (special) I-30 ℃ transformer oil (naphthenic)

I-40 ℃ ultra-high voltage transformer oil