Transformer oil breakdown voltage testing procedure. Enter your email below to receive free informative articles on electrical. Testing sequences and procedures are defined by various international standards, many of them set by astm. An oil test can be performed quickly and economically, as the testers can be taken onsite and therefore no oil sample needs to be shipped to a test laboratory. Study of transformer oil purification shreya salvi, prof. Transformer oil test methods include astm, bs,and other recognized transformer oil analysis testing procedures. The dielectric strength of transformer oil is mainly determined by the presence of acids, water, and other contaminates. Transformer oil testing quick, simple and onsite b2hv. Transformer oil received in drums must be stored on an elevated platform. This test can give an early indication of abnormal behavior of the transformer. Transformer oil filtration machine series yhzyd yeloco.
A wide variety of transformer oil tester options are available to you, such as usage, power. The bdv of oil in transformer is 60 kv1 min within the gap of 2. Transformer oil purification filtration processprocedure. A wide variety of transformer oil tester options are. When transformer is to be filled or topped off in the field, they must be filled under vacuum according to specific instruction. The sfl is the number of hours the oil remains sludge free. So, the transformer oil filtration machine is required to purify used transformer oil and keep the transformer oil absolutely clean. A larger quantity of oil is needed for these tests. During the transformer operation for a period, insulation oils will become dirty degradation which results in loosing function of the oil in transformer as insulation and cooling, in that case, transformer will face some serious problems. Oil to be tested is placed in a cell containing one pair of electrodes placed with a gap of 2. Acidity accelerates the oxidation process in the oil.
Predicted oil bdv size of testing set samples prediction accuracy 1 96. Minimum standard specific resistance of transformer oil at 90c is 35. The middle layer is a processing device which process the. Dissolved gasin oil analysis the most important test that can be done on the liquid insulation of a transformer is an annual dissolved gas analysis dga. Testing sequences and procedures are defined by various international. 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 cleaned magnetic stirrer bar as dropped to the vessel so that it is placed at center. Testing consists of measuring breakdown voltage and. The acidity level of transformer oil is measured as per british standard bs2000 part 1. An oil test can be performed quickly and economically, as the testers can be taken onsite and therefore no oil sample needs to be shipped to a test laboratory the whole test sequence including stirring and repeated measurement is carried out automatically. The vessel was cleaned thoroughly and filled with sample oil until the level is about 12mm from the top. Transformer oil sample testing bdv test service provider. Specific transformer oil test method availability will vary depending upon location.
Series yhzyd doublestage vacuum transformer oil filtration machine application. The test shall be conducted in a dry place free from dust and voltage. The different insulating materials have different dielectric strength. After installation of transformer on the plinth, accessories viz. These tests include dielectric breakdown, power factor, interfacial tension, acidity, and color. The significance of the test it will detect free water, dirt and conductive particles. Connect the earth terminal on the right side of the equipment to the earth wire firmly before start the equipment. Nov 17, 2019 the acidity of insulating oil is generally measured by the required quantity in milligram of koh to entirely neutralize the acidity of a specific quantity in gram of the oil. It is mainly used for purifying the insulating oil.
The acidity of insulating oil is generally measured by the required quantity in milligram of koh to entirely neutralize the acidity of a specific quantity in gram of the oil. To determine dielectric strength, transformer oil is periodically tested by means of an oil punching apparatus. The mounted electrodes were separated from the container. The megger guide to insulating oil dielectric breakdown. If the technique of dissolved gas analysis is excluded, oil tests can be divided into two basic groups.
Acidity test of transformer insulating oil electrical4u. The megger ots range of dielectric breakdown voltage test sets. A new transformer oil shol\uld have at least dielectric strength of 39 kv as per british standards. After the transformer oil test is completed, the insulation oil is stirred automatically and the test sequence is performed repeatedly. Service provider of transformer oil sample testing bdv test, acidity test offered by pallavi trafotech, vijayawada, andhra pradesh. So, insulation overheating measurement is also transformer oil testing methods. The transformer oil testing device measures and reports the root mean square value of the breakdown voltage. Transformer oil breakdown voltage gives an indication about the. Breakdown voltage is measured by observing at what voltage, sparking strands between two electrodes immersed in the oil, separated by a specific gap. Replace the transformer and core to be lifted for thoroughly checking. Also the hard copies as per specification shall be submitted. The insulating material should sustain the voltage up to its dielectric strength.
Study of dielectric breakdown performance of transformer oil. Learn what transformer oil is, how to test transformer oil and the different types and properties. During filtration, temperature of oil must remain within 60. There are several methods of interpreting dissolved gas analysis data in transformers filled with beta fluid. Lowcost manual instruments are still available, but think. Apr 29, 2016 the test procedure for bdv test is as follows. Keywordsautomation using arduino, oil breakdown voltage. The screen test is a collection of physical, electrical and chemical tests for the transformer oil. About 80% of these are testing equipment, 6% are other test instruments. Tests at d and e may be carried out on more than one unit subject. The dielectric strength of transformer oil is very important since it is essential in maintaining the reliable operation of power transformers. Actual oil bdv predicted oil bdv size of testing set samples prediction accuracy 1 96.
An internal fault in a transformer can be discovered earliest using this test method. Degasification, insulating oil, moisture, purification, transformer. As oil has to be broken down into very specific forms such as transformer oil, making sure it is still in the correct form is an essential process. Testing and commissioning of hv power transformers. Pdf significance of transformer oil testing researchgate. A low value of bdv indicates presence of moisture content and conducting substances in the oil. If regularly conducted, oil analysis allows identification of specific fault conditions that may be developing. Due to the ultra fast voltage switchoff at flash over free operation of power transformers is a factor of major economic importance and safety in power supply utilities and industrial consumers of electricity.
Meggers experience in the design and production of oil test sets also reaches back to the early 20th century, when pioneering equipment was produced by foster transformers, a company that became part of megger group in 1968. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Transformer oil used are normally tested using astm d87782 with the kv strength testing,using 1 electrode spaces 0. The megger guide to insulating oil dielectric breakdown testing.
Once power transformer is charged and commissioned, transformer oil becomes a key. The dielectric strength of transformer oil is also known as the breakdown voltage bdv of transformer oil. Mineral oil is the most common insulating fluid and has been in use since the late 19th century. The pfvo and sfl are run concurrently from the same test setup. Transformer is one of the main asset in the electrical power industry which needs to be maintained for guaranteed uninterrupted power transmission in order to get assured revenue benefits. The oil testers by b2hv are of compact design and portable ba75 oil tester. Before filling oil in transformer through filter machine, it has to be filtered separately in oil tanks and ensure bdv and ppm value. In chapter three and four, an extended discussion on the transformer oil properties is made, taking into consideration the eleven most important ones. The dielectric strength of an oil still ranks as the most common field test.
Testing and commissioning of hv power transformers, circuit. In this paper, we will study about the transformer oil filtration machine and how it purifies the contaminated transformer oil. It is usually obtained by fractional distillation and subsequent processing of crude oil. Dissolved gasinoil analysis the most important test that can be done on the liquid insulation of a transformer is an annual dissolved gas analysis dga. However, it really depends on the application and again, the type of oil. Bdv test is an very important testing procedure for the insulation oils in transformer. Break down voltage is measured by observing at what voltage, sparking. Pdf dielectric strength measurement is the most primitive test which decides the.
Current transformers cts voltage transformers cvts ivts 1. Take corrective action according to observations and oil test report. To gather the sample, a clean, moisture free container must be used typically a plastic. Peaobdvmxxx automatic oil breakdown voltage tester features available in 100kv m100, 80kv m080 and 60kv m060 versions. A dga test can identify an overloaded transformer by a test result showing high carbon monoxide, high carbon dioxide, and in extreme cases, even elevated methane and ethylene. Minimum breakdown voltage of transformer oil or dielectric strength of. Adjust the electrode distance inside the oil cup with standard gauge. A free powerpoint ppt presentation displayed as a flash slide show on id. It is therefore, important to keep the transformer oil as free from such contaminates as possible. Any internal fault such as short circuited core, core bolts clamps insulation failure etc. Troubleshooting transformer in power substation and. Transformer oil is used in oil filled electrical power transformers to insulate, stop arcing and corona discharge, and to dissipate the heat of the transformer i. For educational purposes only, under proper supervision of laboratory professionals video edited by. Routine testing of transformer oils and insulating oils on a regular schedule is an accepted industry.
For measuring bdv of transformer oil, bdv measuring kit is used. Evaluation of transformer condition using individual and tdcg concentrations. Dissolved gas analysis guide for transformers filled with. As the name implies, this test analyzes the type and quantity of gases that are dissolved in the transformer oil. Aug 30, 2019 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. Depending on the type of oil used the breakdown voltage can be up to 60kvmm dried oil or 40kvmm non dried oil. Transformer oil analysis basic introduction by n robinson, wearcheck as blood tests disclose ones state of health, so oil analyses disclose the condition of a transformer.
Transformer oil breakdown voltage bdv test youtube. Worlds only true bdv setmeasures hv secondary voltage across oil vessel electrodes, instead of across hv primary. What is the minimum value of breakdown voltage of transformer. Today, all of meggers oil test set design, development and manufacture is carried out at the companys. As you already know, substations are the points for controlling the supply of power on different routes by means of various equipment such as power transformers, circuit breakers, ctsvts, compensating equipment, isolators, etc. The positive li bdv test was conducted for both oil and developed.
Dec 15, 2016 for educational purposes only, under proper supervision of laboratory professionals video edited by. Due to the ultra fast voltage switchoff at flash over transformer oil purification procedure. 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. Testing oltc on load tap changer tests for reference signature tests on main protective relays. The electrical properties of oil can suddenly change due to changes in oxidation, acids, sludge gas and even water absorption, so.
Transformer oil, a type of insulating and cooling oil used in transformers and other electrical equipment, needs to be tested periodically to ensure that it is still fit for purpose. The following are the methods that are recommended by dielectric systems, inc. Astm d1816 standard test method for dielectric breakdown voltage of insulating oils of petroleum origin. Drums are to be horizontally placed with its opening cap in middle. Ppt transformer oil processing powerpoint presentation. The test is performed as per astm d3359 standard test methods for measuring adhesion by tape test. Tan delta testing in tamil insulation ageing test loss angle test dissipation power test duration. Pdf development of an automated break down voltage test set. The transformer oil is used in the transformer for insulation as well as for cooling purpose.
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