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How can you test the dielectric strength of oil of transformer?
Wiki User
∙ 10y ago
dielectric strength is tested by transformer dielectric strength oil testing machine. at first, oil which is to be tested is pour near the two electrode. both the electrode should be dipped in oil . then adjust the distance between the electrode .now start the machine.when a sound came from machine then note down the dielectric strength of the oil.
Wiki User
∙ 11y ago
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How do you stop oil leakage in Transformer?
If you have a large power transformer that is leaking oil, do NOT touch it! Older transformer oil contains PCB's which are extremely toxic!! Get a licensed firm to test the oil for PCB's and repair or replace the transformer. Don't fool around with this! PCB's are a serious danger to you and others. Do not let this go. Get it fixed right away!
What is the breakdown voltage of transformer oil?
the break down strength of transformer oil is in between 30kv and 40kvCommentA breakdown voltage doesn't mean anything unless it is expressed in terms of distance -e.g. volts per millimetre.
How do you test dc voltage from a transformer?
On TRANSFORMER OIL BREAK DOWN VOLTAGE test is carried out which is done on field while filling the oil in transformer. This process is also called oil filtration.1.Take sample from top of Transformer before filtration.2.The BDV of oil should withstood min 50 KV3.The gap between the test electrodes sample to be 2.5mm maintained4.At least 5 sample(top/bottom) should be checked separately while filtration.5. The samples should withstand 50 kv for 1 min.5. Take the average of all the samples timings.You will get value.7.Procedurea.Voltage should be gradually increased from 0.b. At one point Flash will take place and that point istermed as Bread down VoltageThe break down characteristics depends upon initial moisture content of transformer & oil. The electrical strength of oil depends upon the water content in transformer & temperature gradient. The electrical strength of oil is reduced if the water content is more than 2%.===============================================================There are several standard test, specific components are needed to conduct these tests, although, like a car's motor oil, a visual inspection can determine the amount of oxidation, and broken-down mateial in the oil. See the related links for typical tests.i would like to add here, regarding tests. we can do various test like dissolved gas analysis(DGA), check for furan compounds- it shows damage to the insulation, etc to check the transformer oil and take various actions.Another Answer:There are a variety of tests offered by Utility Testing Laboratoies that track dielectric oil quality including:Dissolved gasDielectric strengthAcid numberColorInterfacial tensionAll tests are performed according to ASTM methods. Standard turnaround for sample testing is 2 weeks. Utility Testing Laboratories can be contacted by phone 8:30am-6:00pm (MST) M-F at (801) 458-891 or find them online at http://ut-labs.com/index.html
What is the Difference between a Dielectric Test and a Megger Test?
a megger or hipot test involves raising the voltage of the wiring to 2x the operating voltage + 1000v answer volts/amps or ohms Dielectric test usually a sample of the oil is taken from the transformer answer is in ohm-cm dry devices will have the dielectric tests on file ... this is a very poor excuse ... the code need rewriting. the old standards were based on porcelain, oil, paper and cotton AI MI SWC DWC new types THN THWN THHN SO are generally based on a natural color when the tests are done so if you replace a cord on a drill the white and green wire has insulation that crumbles while the black is still flexable. thermoplastic insulation used for several years in damp locations with DC turns to a sticky goo.
What is the present excise duty of transformer oil?
to cool a winding of transformer and it is a insulating material and transformer oil is a purifing oil
How can you find dielectric strength of oil in transformer?
by spark gaps immersed in the oil sample
What is BDV test for distribution transformer?
When you say BDV you might mean the dielectric strength of transformer oil. A new transformer oil should have at lest a dielectric strength of 39 KV. from a British standard.Transformer oils used are normally tested using ASTM D877-82 with the KV strength tester using 1" electrodes spaced 0.1" apart and the test voltage increased at 3,000 volts/min until it breaks down. The average Kv obtained after 8 trials is considered the Oil dielectric strength.Using this test method,dielectric strength at 30 kv and above is considered good. Dielectric strength between 23 to 29Kvis considered usable, but requires filtering. Below 23 kv, the transformer oil should be replaced.Another method ASTM D18747-82 uses the small radius electrodes but spaced only .o4 inches. The test voltage is 500volts/min and increased until breakdown. The dielectric strength is still the average Kv obtained in 8 trials. The dielectric strength of 28-29Kv is considered good. Below 28 kv, the transformer oil is usable but requires filtering. The latter method is considered a better test method
How do you check transformer oil thermal stability?
An Oil Dielectric Strength Tester is the standard for qualifying Transformer Oil. Thermal Stability would involve heating and then testing. I do not know of a product which controls heat and applies the HV test.
WHAT will happen if you run oil transformer with out oil?
As well as providing a cooling medium, transformer oil is also used to insulate a transformer. As its dielectric strength (how well it insulates) is much higher than air, it means that components within a transformer that are at different potentials can be placed much closer together if they are immersed in oil. So, operating an oil-filled transformer without oil will likely cause insulation breakdown within the transformer.
Why required oil inside the transformer?
To cool and to insulate the transformer. Transformer oil has a higher specific heat capacity than air, so it is more efficient at removing energy through heat transfer, and limiting the windiings' temperature rise. Transformer oil has a much greater dielectric strength than air, which means that components at different potentials can be placed closer together, so the overall volume of the transformer can be made smaller, giving it a smaller 'footprint'.
What is the properties of good transformer oil?
The main function of transformer oil is insulating and cooling of the transformer. It should have the following properties:High dielectric strengthLow viscosityFreedom from inorganic acids, alkali, and corrosive sulfurResistant to emulsificationFreedom from sludging under normal operationRapid settling of arc productsLow pour pointHigh flash point
What is the hermetically sealed transformer?
Hermatically sealed transformer is a transformer design which has no conservator. Here the dielectric insulating fluid in the transformer tank is completely sealed and is in zero contact to the atmosphere. This type of transformer is used in applications where the transformer is to be installed in harsh climatic conditions(smoke,pollution,dusty environment,etc) or user prefers low maintenance transformer. The design avoids air in the transformer tank therby avoiding sludging and oxidation of the dielectric fluid. Hence it would be safe to say that these transformers need no maintenance of the dielectric insulatating fluid(usually Oil). Normally these type of transformers are accommodated by devices that measure heat related volume variations. Gas cushion is used to compensate the volume variation due to heat. Normally the gas is nitrogen. This gas is thermally uncoupled from the dielectric liquid.
Will petroleum jelly conduct electricity?
No, it is a petroleum/wax/oil based compound. Electrons do not freely travel between molecules, in that, it's a dielectric. Similarly to the dielectric fluid in a transformer, petroleum jelly can be used as an insulator. It's thermal conduction isn't as good.
How do you stop oil leakage in Transformer?
If you have a large power transformer that is leaking oil, do NOT touch it! Older transformer oil contains PCB's which are extremely toxic!! Get a licensed firm to test the oil for PCB's and repair or replace the transformer. Don't fool around with this! PCB's are a serious danger to you and others. Do not let this go. Get it fixed right away!
Is oil in transformer use for lubrication?
Transformer oil is for cooling.Transformer oil has heat conductive properties, along with its insulating properties, that take the heat build up from the windings to the outer case of the transformer. The transformer tank is used as a heat sink to allow the outside ambient temperature to cool it down. On big kVA transformers there are heat tubes on the outside of the tank. On even bigger transformers there are fins that the oil travels through. This provides a bigger surface area to dissipate the heat. The tubes and fins also allow thermal siphon of the oil through the tubes by drawing in the cooler oil at the bottom of the tank and moving it to the top of the tank where the hotter oil is. This circulation greatly increases the cooling ability of the oil to keep the transformer with in its allowable temperature rate of rise zone.Additional AnswerThe second function of transformer oil is insulation. Oil has a far greater dielectric strength than air, so it enables internal components at different potentials to be located far closer together -thus significantly reducing the 'footprint' of a transformer.
What is oil transformer?
Transformer oil is pure insulating oil.
What is the breakdown voltage of transformer oil?
the break down strength of transformer oil is in between 30kv and 40kvCommentA breakdown voltage doesn't mean anything unless it is expressed in terms of distance -e.g. volts per millimetre.
