The air moisture should be resisted during entering of the air into the , because moisture is very harmful for transformer insulation. Transformer Oil Testing Methods Value. Different gasses will dissolve in the oil that indicate various types of thermal and electrical stress occurring within the transformer. New oil often requires further degasification to remove air and moisture added during transportation and handling procedures. Transformer oil also known as insulating oil is a special type of oil which has excellent electrical insulating properties and is stable at high temperatures. The bolts should be tightened evenly around the joints to avoid uneven pressure. New transformers may contain particles of insulating materials and other solid impurities.
This is completed by circulating the oil through the degasification process and the transformer to heat the transformer. When all of the white light components are absorbed we see black. Oil filled transformers with a conservator oil reservoir may have a gas detector relay. Oil level in bushing gauge glass be properly maintained with transformer oil of the same grade and quality. There are various manufacturers of portable oil testers.
When blue is absorbed we see yellow, when violet is absorbed one sees yellow-green, absorbed cyan lets us see orange. Larger transformers in secured locations behind a security fence will have a valve on the bottom of the tank that is readily accessible. Use your best judgement on whether or not to de-energize. Working Principle of Silica Gel Breather Silica gel crystal has tremendous capacity of absorbing moisture. The acidity of transformer oil is measure of its acidic constituents of contaminants. Analyses of solid insulating materials, conductive metallic materials grain-oriented electrical steel and copper materials as well as coating materials and sealing materials, are carried out. Sludge formation on the windings has a snowball effect on the transformer with more sludge creating more heat, creating more sludge etc.
It is possible to restore oil to new oil specifications with a combination of these treatments. A failure of a transformer can result in significant environmental clean up costs. The dielectric breakdown voltage is measured by applying a voltage between two electrodes under the oil. It is particularly important that heavy current carrying connections should be properly maintained. Unsourced material may be challenged and. During the mostly decades-long service life of a transformer, materials too are subjected to considerable ageing processes. The inside of the conservator should be cleaned periodically.
Moisture and gas content in transformer oil must be tested for thoroughly. Transformer Oil Testing is a proven loss prevention technique which should be a part of any condition based predictive maintenance program. That is the same for oil. Insulation overheating The paper insulation which is normally used to insulate the windings of a transformer is a cellulose product. Environmental Concerns Mineral insulating oil is a valuable resource that can be recycled many times and returned to its original condition.
The absorbed air is released only in initial period on charging and loading, when no vacuum is applied during filling of oil in transformer. The quality of insulation declines during the aging process, to different extents, depending upon various operating conditions, due to both physical and chemical effects. The coils may also get displaced under load conditions or momentary short circuits, which may cause electric and magnetic unbalance and produce even greater displacement. With transformer oil this is done through testing of the oil. The analyzed oil color is assigned a number ranging from 1 to 8, whereby the level of discoloration is indicated by means of the rising color number.
It is the intension of this specification to define a mineral insulating oil that is functionally interchangeable and miscible with existing oils, is compatible with existing apparatus and with appropriate field maintenance, and will satisfactorily maintain its functional characteristics in its application in electrical equipment. Lot of research and experiments are going on, regarding mixing of oils. This further degasification will increase the life expectancy of the oil in the transformer. It is a paint of higher coverage than acrylic paint and has strong plasticity. The cause of any serious loss of oil should be investigated. Specific transformer oil test method availability will vary depending upon location. Colour of transformer oil products are most popular in Southeast Asia, South America, and Domestic Market.
This mixture gives momentary flash on the application of flame under standard condition. Flash point is one of the driving factors of which type of oil is to be used. This is also the case when the core and yoke parts of the transformer had got damaged. Decreasing dielectric strength is caused by contamination of the oil by gas, moisture, cellulose fibers or other particulate matter. Cloudiness or sediment indicate free water, insoluble sludge or dirt particles.
An oil sample tube and syringe is used to draw, retain and transport the oil sample in the same condition as it is inside a transformer with all fault gases dissolved in it. The external causes may be excessive overloading on the transformer, short circuits near the transformer, failure of other auxiliary equipment nearby, failure of its controlling breaker, failure of protection to operate and so on. Usually whatever is available on the market at the time of manufacture. If the resistivity of the insulating oil gets decreased, the value of tan-delta increases and vice verse. Physical Parameters of Transformer Oil Inter Facial Tension of Transformer Oil Interfacial tension between the water and oil interface is the way to measure the attractive molecular force between water and oil.