The transparent, shielded lid and large test chamber enable easy access to the test vessel. Breakdown voltage is measured by observing at what voltage, sparking strands between two electrodes immersed in the oil, separated by a. The transformer oil testing device measures and reports the root mean square value of the breakdown voltage. The best way to test the breakdown voltage of transformer oil is to use a transformer oil test kit. Dielectric strength is an indicator used to assess insulation properties of transformer oil. It refers to the dielectric strength of transformer oil. Transformer oil, a type of insulating and cooling oil used in transformers and other electrical.
Break down voltage test of transformer oil duration. Breakdown voltage the breakdown voltage for all samples can be seen in table 3. The test voltage would be about 2 working voltage and the voltage is maintained from 15 min to 1. To assess the insulating property of dielectric transformer oil, a sample of the transformer oil is taken and its breakdown voltage is measured. We will first consider the vegetable oil which has less dielectric capabilities than the mineral oil used in power transformers. It is very often equated with breakdown voltage, but their numerical values are not equal. Each breakdown voltage test is required as much as 400 ml figure 7. In the dielectric strength test of transformer oil, the test voltage should be raised to the specified value or the breakdown voltage if it is less at a uniform rate in 1015 seconds and maintain for a one minute. The lower the resulting breakdown voltage, the poorer the quality of the transformer oil. The megger guide to insulating oil dielectric breakdown testing. Breakdown voltage is an important test for transformer oil. Moulded test vessels give repeatable results with lock in precision electrode gap setting adjustment wheels. Which oil testing standard should you choose to determine. No single test alone will represent or indicate the true condition of the liquid.
During the time of transformer operation, the oil will become degradation which may be the main cause for loss of function, decreasing the cooling capacity of the transformer, and etc. Oil in each instance degrades over time resulting in the potential for failure or costly repair bills. The effect of moisture on the breakdown voltage of. Dielectric breakdown the dielectric breakdown test is a physical test that measures the breakdown voltage of an insulation liquid. According iec standard, six measurements were carried out on the insulating oil. However, it really depends on the application and again, the type of oil. Usually the contaminant is water, but it can also be conductive particles, dirt, debris, insulating particles and the byproducts of oxidation and aging of the oil. Determining the dielectric breakdown voltage of insulating liquids is important to understand the insulating liquids ability to withstand electric stress without failure. A larger quantity of oil is needed for these tests.
Due to the ultra fast voltage switchoff at flash over transformer oil testing of synthetic oil, ester oil and silicone oil is possible. Dielectric strength means the maximum capacity to withstand voltage of insulating oil. Break down voltage is measured by observing at what voltage, sparking straits between two electrodes emerged in the oil, separated by specific gap. It is thus normal to subject the cable soon after laying it, but before energising it to carry out a high voltage test under d. Through proper testing, the transformer s lifespan is increased, reducing the need to pay for replacement. In addition, aging of the transformer oil was simulated for. Pdf breakdown voltage of the transformer oils under certain. The effect of moisture on the breakdown voltage of transformer oil materials and methods the transformer oil samples used in this study table 1 were three mineral oils, one synthetic esterbased oil, and two mineral oil samples taken from transformers in operation. Oil tester breakdown analyzer ba60 ba75 ba80 ba100 b2hv. Breakdown voltage of the transformer oils under certain conditions. To determine dielectric strength, transformer oil is periodically tested by means of an oil punching apparatus. Its functions are to insulate, suppress corona discharge and arcing, and to serve as a coolant.
The effect of moisture on the breakdown voltage of transformer oil. Transformer oil testing quick, simple and onsite b2hv. Connect the earth terminal on the right side of the equipment to the earth wire firmly before start the equipment. How to test the breakdown voltage of the transformer oil. Therefore, it is suggested that they all be performed. It is used in oil filled transformers, some types of high voltage capacitors, fluorescent lamp ballasts, and some types of high voltage switches and circuit breakers. The transformer oil breakdown voltage test set supplied shall be preprogrammed atleast in accordance with the latest editions of the standard test methods specified in iec 60156 and amendments thereof.
There are many types of organisation that benefit from carrying out tests on transformer oil. Dielectric breakdown voltage and dielectric strength. If the breakdown voltage of the oil is on the lower side it means that it is of poor quality. Meggers automatic laboratory oil test sets perform accurate breakdown voltage tests on mineral, ester and silicon insulating liquids. Dielectric breakdown d1816 the dielectric breakdown is the minimum voltage at which electrical flashover occurs in an oil. Transformer oil act as an insulating medium and also as a coolant that dissipates heat of the transformer. This paper has studied the breakdown voltages of transformer oil and. Transformer oil or insulating oil is an oil that is stable at high temperatures and has excellent electrical insulating properties.
The approximatecompositions of niirabers1 to 6 inclusive fur. It can be seen that the value of breakdown voltage spherical is higher than that of the mushroom electrode. Dielectric breakdown voltage and dielectric strength date 1086 revision page2of3. Breakdown voltage bdv in transformer oil powerlink oil. To test the oil sample, transformer oil is poured into a porcelain vessel in which two disk electrodes, one of 8mm diameter and one of 25mm diameter, are mounted. A low breakdown voltage value can be a clear indication of contamination within the liquid from the degradation processes that occur during the lifetime of a transformer. Jy6611 transformer oil breakdown voltage tester use advanced voltage breakdown control technology which will keep breakdown energy in a very low level,that will avoid pollution to oil sample during testing and make sure the test result are accurate and reliable. For your application you might get away with 2030 kvmm.
Each test is an indication of how suitable the insulation liquid is for service. Baur dielectric strength oil testers hv technologies inc. Transformer oil maintenance electric energy online. Veer make oil bdv is specially designed for testing oil breakdown voltage. To gather the sample, a clean, moisture free container must be used typically a plastic. Breakdown voltage is a minimum voltage applied to an insulation, resulting in its breaking down and becoming electrically conductive. After breakdown occurred, the test voltage was automatically switched off. Depending on the type of oil used the breakdown voltage can be up to 60kvmm dried oil or 40kvmm non driedoil. Regular maintenance and upgrading of the oil will add years to the life of both your car and your transformer.
When the current arcs across this gap the voltage recorded at that instant is the dielectric strength breakdown strength of the insulating liquid. To determine the insulating property of the dielectric oil, an oil sample is taken from the device under test, and its breakdown voltage is measured onsite in the vessel, two standardcompliant test electrodes with a typical clearance of 2. The first test circuit was for generating impulse voltage with. As a result the breakdown voltage is calculated as mean value of the individual measurements. Oil dielectric ac test sets provide replicable, accurate measurement of breakdown voltage of insulating oils used in electrical equipment. The dts series provides repeatable and accurate measurements of the breakdown voltage of insulating oils used in electrical equipment. This test method is applicable to insulating liquids commonly used in cables, transformers, oil circuit breakers, and similar apparatus as an. Breakdown voltage bdv testing of transformer oil youtube.
Transformer oil hp transformer oil i hp lubricants. It is fully automatic test kit developed to test oil sample as per is6792iec 60156 with printer facility. The breakdown voltage was the voltage that causes an electric arc which leads to a collapse of the test voltage. It is commonly used in transformers because of its chemical properties and. After the transformer oil test is completed, the insulation oil is stirred automatically and the test sequence is performed repeatedly.
Test sequences can be accomplished easily and fully automatically in compliance with all international and national standards. The main aim of such a test is to examine the insulating property of the oil in a dielectric transformer. Inhibited transformer oils can extend the service life of transformer oil. Oil testing consists of measuring the breakdown voltage, and other chemical and physical properties of the oil, either through portable test equipment or in a laboratory. The screen test is a collection of physical, electrical and chemical tests for the transformer oil. The test involves applying a ac voltage at a controlled rate to two electrodes immersed in the insulating fluid. The bdv of oil in transformer is 60 kv1 min within the gap. There are many equipment such as transformers, high voltage cables, insulators, breakers, etc. Various predefined and fully automatic test sequences meet all relevant international standards, thus the models of the ba series fulfill all legal requirements of the mandatory. The petroleum or mineral oil based transformer oil samples considered for this presentation are tested for various parameters following the procedure and guidelines as per is. The baur dta 100 c oil breakdown voltage tester fully automatically tests the electrical breakdown strength of insulating liquids.
Experimental study on breakdown characteristics of transformer. The main physical and chemical properties tested in transformer oil testing methods are the oil s dielectric strength, dissipation factor, flashpoint, color, amount of solid particulate matter, water content, gas content and the oil s acid number. The transformer oil is filled in the vessel of the testing device. Breakdown voltage value of insulating oil of the transformer. Oil quality transformer oil is a mineral based oil. Dielectric strength of transformer oil is also known as breakdown voltage of transformer oil or bdv of transformer oil. Transformer oil breakdown voltage testing procedure. Oil bdv tester transformer oil test kit oem manufacturer. The test is performed with two or three consecutive samples of oil turn by turn. Insulating oil in electrical power apparatus serves two primary roles, as an insulator and a coolant. The moisture level of the oil relative to saturation water activity in oil was determined using a vaisala mmt330 transmitter with the probe installed in the test cell of. Testing consists of measuring breakdown voltage and other physical and chemical. Based on the test results, the oil can be identified as aged due to an increase in water content, sludge, or if the oil has oxidized. Ots100af, ots80af and ots60af laboratory oil testers.
Bdv test is used to test or check the quality of transformer oil. Experimental study on the dielectric breakdown voltage of. Breakdown voltage characteristics of castor oil as. Transformer oil breakdown voltage tester or bdv tester is required to do breakdown voltage test and to check the dielectric strength of the oil of the transformer. The megger guide to insulating oil dielectric breakdown. Break down voltage test of a 2 kv power transformer oil. A transformer oil breakdown test set is an equipment that measures the dielectric strength of the oil. This test shows the dielectric strength of transformer oil. These lightweight, rugged units are designed for field and laboratory use. The insulation oils are used in such systems to provide the insulation and cooling respectively for high.
Later in the experiments, we will focus mainly to examine the breakdown voltage. Electrical breakdown testing of magnetic nanofluids found that for positive streamers. As an insulating liquid, oil s most important property is a high dielectric strength and as a cooling liquid, a low viscosity is paramount. Breakdown voltage of the transformer oils under certain. Basic features the transformer oil tester shall be capable of measuring dielectric breakdown voltage of all. Who needs to perform dielectric breakdown voltage tests.1411 65 647 288 862 1209 1224 566 1561 803 1576 15 293 1557 1440 591 1458 1421 454 1577 473 766 444 15 758 409 1089 1026 1489 868 534