Just as a car requires regular checks of both oil quality and oil level, a transformer requires the same proactive treatment. Oil in each instance degrades over time resulting in the potential for failure or costly repair bills. Oil should be procured from reliable source or use of “TRANSPOWER” Transformer oil will add years to the life of your Equipment’s/Transformer. We known as best transformer oil manufacturer and supplier in India.

Knowledge Base

Transformer oil or insulating oil is usually a highly refined mineral oil that is stable at high temperatures and has excellent electrical insulating properties. It is used in oil-filled transformers, electrical transformer oil applications, some types of high voltage capacitors, fluorescent lamp ballasts, and some types of high voltage switches and circuit breakers. Its functions are to insulate, suppress corona and arcing, and to serve as a coolant. In an oil cooled transformer, this oil plays a vital role in dissipation of heat and maintains the equipment’s efficiency and reliability.

A mineral oil is any of various colourless, odourless, light mixtures of ALKANES in the C15 to C40 range from a non-vegetable (mineral) source, particularly a distillate of petroleum. The name mineral oil by itself is imprecise, having been used to label many specific oils over the past few centuries. Other names, similarly imprecise, include white oil, liquid paraffin, and liquid petroleum. Most often, mineral oil is a liquid by-product of the distillation of petroleum to produce gasoline and other petroleum-based products from crude oil. A mineral oil in this sense is transparent, colourless oil composed mainly of alkenes and cyclic paraffin’s, related to petroleum jelly (also known as “white petrolatum”).

Transformer oils are subject to electrical and mechanical stresses while a transformer is in operation. In addition there is contamination caused by chemical interactions with windings and other solid insulation, catalyzed by high operating temperature. The original chemical properties of transformer oil change gradually, rendering it ineffective for its intended purpose after many years. Oil in large transformers and electrical apparatus is periodically tested for its electrical and chemical properties, to make sure it is suitable for further use. Sometimes oil condition can be improved by filtration and treatment.

The oil helps cool the transformer. Because it also provides part of the electrical insulation between internal live parts, transformer oil must remain stable at high temperatures for an extended period. To improve cooling of large power transformers, the oil-filled tank may have external radiators through which the oil circulates by natural convection. Very large or high-power transformers (with capacities of thousands of kVA) may also have cooling fans, oil pumps, and even oil-to-water heat exchangers.

Large, high voltage transformers undergo prolonged drying processes, using electrical self-heating, the application of a vacuum, or both to ensure that the transformer is completely free of water vapour before the cooling oil is introduced. This helps prevent corona formation and subsequent electrical breakdown under load.Oil filled transformers with a conservator may have a gas detector relay (Buchholz relay). These safety devices detect the build up of gas inside the transformer due to corona discharge, overheating, or an internal electric arc. On a slow accumulation of gas, or rapid pressure rise, these devices can trip a protective circuit breaker to remove power from the transformer. Transformers without conservators are usually equipped with sudden pressure relays, which perform a similar function as the Buchholz relay.

Handling and Storage of Transformer Oil

To ensure satisfactory service, the utmost care in handling oil is essential. Filled drum of Transformer oil should be kept under cover. In practice owing to contamination in the containers, difficulty may be experienced in maintaining the purity of the oil when it is transferred from one vessel to another, and once a vessel or drum has been filled with moist oil it is extremely difficult to clean. Drum should be clearly marked to indicate whether they are for clean or for dirty oil and should be reserved for the type indicated.

It store in the storage tank should be preferably with cover and air tight fitted with lid and small pipe with silica get fitted on top for breathing the tank. The end of the delivery pipe should be held below the surface of the oil in order to avoid splashing. The storage tank should be filled from the bottom.

Method for Sampling of Transformer Oil in Drum and Storage Tank

PRECAUTIONS: Every precaution shall be taken , when sampling so as not to contaminate the Transformer oil with dirt, dust fibrous matter or moisture. Outdoor sampling of Transformer oil in rain, fog or high wind should be avoided. The operator is warned not to permit his hands to come in contact the sample or the internal surface of sampling container.

The sample of oil should be protected against all kinds of light radiation during sampling & storage. The sample bottle shall not be opened immediately. It is necessary to wait till the temperature of the sample is in equilibrium with room temperature.

Sampling equipment: All sampling equipments should be reserved for exclusively taking the sample. The equipment shall be perfectly clean and dry and preferably be made of glass or stainless steel.

Sampling from Road Tanker may be done through the Tank outlet. The sample should be drawn after the vehicle has been allowed to stand for at least one hour from the time of its arrival. Sampling from Drum should be taken only after the drums have been allowed to stand for at least 8 hours with the bung intact on top, protected from dust or rain. The bungare and top surface of the drum shall be cleaned with lint free dry cloth before opening.

Follow all procedure as per IS 6855:2003 Method of Sampling for Liquid Dielectrics issue by Bureau of Indian Standard