As the name implies, this test analyzes the type and quantity of gases that are dissolved in the transformer oil. 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. Lowcost manual instruments are still available, but think. The megger guide to insulating oil dielectric breakdown testing. Transformer oil purification filtration processprocedure. The mounted electrodes were separated from the container. A wide variety of transformer oil tester options are available to you, such as usage, power. Worlds only true bdv setmeasures hv secondary voltage across oil vessel electrodes, instead of across hv primary.
Today, all of meggers oil test set design, development and manufacture is carried out at the companys. Testing and commissioning of hv power transformers, circuit. Learn what transformer oil is, how to test transformer oil and the different types and properties. The pfvo and sfl are run concurrently from the same test setup. So, insulation overheating measurement is also transformer oil testing methods. Connect the earth terminal on the right side of the equipment to the earth wire firmly before start the equipment. Testing consists of measuring breakdown voltage and. Evaluation of transformer condition using individual and tdcg concentrations. Bdv test is an very important testing procedure for the insulation oils in. The sfl is the number of hours the oil remains sludge free. Pdf significance of transformer oil testing researchgate.
Drums are to be horizontally placed with its opening cap in middle. 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. The vessel was cleaned thoroughly and filled with sample oil until the level is about 12mm from the top. Testing oltc on load tap changer tests for reference signature tests on main protective relays. Testing sequences and procedures are defined by various international standards, many of them set by astm. A new transformer oil shol\uld have at least dielectric strength of 39 kv as per british standards. A larger quantity of oil is needed for these tests. Pdf dielectric strength measurement is the most primitive test which decides the. The transformer oil is used in the transformer for insulation as well as for. Once power transformer is charged and commissioned, transformer oil becomes a key.
Troubleshooting transformer in power substation and. Bdv test is an very important testing procedure for the insulation oils in transformer. To determine dielectric strength, transformer oil is periodically tested by means of an oil punching apparatus. 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. The significance of the test it will detect free water, dirt and conductive particles. Transformer oil breakdown voltage bdv test youtube. Ppt transformer oil processing powerpoint presentation. Due to the ultra fast voltage switchoff at flash over transformer oil purification procedure. Any internal fault such as short circuited core, core bolts clamps insulation failure etc. The oil testers by b2hv are of compact design and portable ba75 oil tester. Service provider of transformer oil sample testing bdv test, acidity test offered by pallavi trafotech, vijayawada, andhra pradesh.
Mineral oil is the most common insulating fluid and has been in use since the late 19th century. Depending on the type of oil used the breakdown voltage can be up to 60kvmm dried oil or 40kvmm non dried oil. Transformer oil filtration machine series yhzyd yeloco. Peaobdvmxxx automatic oil breakdown voltage tester features available in 100kv m100, 80kv m080 and 60kv m060 versions. For measuring bdv of transformer oil, bdv measuring kit is used. The cleaned magnetic stirrer bar as dropped to the vessel so that it is placed at center. Transformer oil breakdown voltage testing procedure.
It is usually obtained by fractional distillation and subsequent processing of crude oil. Bdv tests is used to test the dielectric strength of the transformer. Testing sequences and procedures are defined by various international. Tan delta testing in tamil insulation ageing test loss angle test dissipation power test duration. Current transformers cts voltage transformers cvts ivts 1. A low value of bdv indicates presence of moisture content and conducting substances in the oil. Predicted oil bdv size of testing set samples prediction accuracy 1 96. A free powerpoint ppt presentation displayed as a flash slide show on id. The transformer oil is used in the transformer for insulation as well as for cooling purpose.
The dielectric strength of transformer oil is very important since it is essential in maintaining the reliable operation of power transformers. The electrical properties of oil can suddenly change due to changes in oxidation, acids, sludge gas and even water absorption, so. When transformer is to be filled or topped off in the field, they must be filled under vacuum according to specific instruction. Bdv means breakdown voltage, also named as dielectric strength valve. Transformer oil test methods include astm, bs,and other recognized transformer oil analysis testing procedures. The different insulating materials have different dielectric strength. Transformer oil testing quick, simple and onsite b2hv. Pdf development of an automated break down voltage test set. 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. 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. These tests include dielectric breakdown, power factor, interfacial tension, acidity, and color.
Astm d1816 standard test method for dielectric breakdown voltage of insulating oils of petroleum origin. However, it really depends on the application and again, the type of oil. Enter your email below to receive free informative articles on electrical. 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. Minimum breakdown voltage of transformer oil or dielectric strength of. The transformer oil testing device measures and reports the root mean square value of the breakdown voltage. Now lets move to, transformer oil purification procedure. In chapter three and four, an extended discussion on the transformer oil properties is made, taking into consideration the eleven most important ones. The test is performed as per astm d3359 standard test methods for measuring adhesion by tape test. It is mainly used for purifying the insulating oil. The bdv of oil in transformer is 60 kv1 min within the gap of 2. During filtration, temperature of oil must remain within 60. Actual oil bdv predicted oil bdv size of testing set samples prediction accuracy 1 96.
About 80% of these are testing equipment, 6% are other test instruments. Break down voltage is measured by observing at what voltage, sparking. In this paper, we will study about the transformer oil filtration machine and how it purifies the contaminated transformer oil. For educational purposes only, under proper supervision of laboratory professionals video edited by. 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. Specific transformer oil test method availability will vary depending upon location. After the transformer oil test is completed, the insulation oil is stirred automatically and the test sequence is performed repeatedly. 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. Take corrective action according to observations and oil test report. The positive li bdv test was conducted for both oil and developed. Routine testing of transformer oils and insulating oils on a regular schedule is an accepted industry. What is the minimum value of breakdown voltage of transformer. 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.
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. Adjust the electrode distance inside the oil cup with standard gauge. In case bdv and ppm values are not achieved within 7 days, check the. An internal fault in a transformer can be discovered earliest using this test method.
Breakdown voltage is measured by observing at what voltage, sparking strands between two electrodes immersed in the oil, separated by a specific gap. Also the hard copies as per specification shall be submitted. Before filling oil in transformer through filter machine, it has to be filtered separately in oil tanks and ensure bdv and ppm value. 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. 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. Dec 15, 2016 for educational purposes only, under proper supervision of laboratory professionals video edited by.
The dielectric strength of transformer oil is mainly determined by the presence of acids, water, and other contaminates. If the technique of dissolved gas analysis is excluded, oil tests can be divided into two basic groups. Transformer oil used are normally tested using astm d87782 with the kv strength testing,using 1 electrode spaces 0. The insulating material should sustain the voltage up to its dielectric strength. Transformer oil breakdown voltage gives an indication about the. Keywordsautomation using arduino, oil breakdown voltage. There are several methods of interpreting dissolved gas analysis data in transformers filled with beta fluid. The megger ots range of dielectric breakdown voltage test sets.
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. The test shall be conducted in a dry place free from dust and voltage. The dielectric strength of transformer oil is also known as the breakdown voltage bdv of transformer oil. The screen test is a collection of physical, electrical and chemical tests for the transformer oil. Tests at d and e may be carried out on more than one unit subject.
The middle layer is a processing device which process the. Minimum standard specific resistance of transformer oil at 90c is 35. Acidity accelerates the oxidation process in the oil. Study of dielectric breakdown performance of transformer oil. Series yhzyd doublestage vacuum transformer oil filtration machine application. It is therefore, important to keep the transformer oil as free from such contaminates as possible. 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. Study of transformer oil purification shreya salvi, prof. The following are the methods that are recommended by dielectric systems, inc.
The acidity level of transformer oil is measured as per british standard bs2000 part 1. To gather the sample, a clean, moisture free container must be used typically a plastic. Degasification, insulating oil, moisture, purification, transformer. 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. 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. 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.
Apr 29, 2016 the test procedure for bdv test is as follows. Testing and commissioning of hv power transformers. Dissolved gas analysis guide for transformers filled with. Transformer oil sample testing bdv test service provider. Replace the transformer and core to be lifted for thoroughly checking. 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. These include the chemical and causes of the specific physical properties of the test oils. The megger guide to insulating oil dielectric breakdown. If regularly conducted, oil analysis allows identification of specific fault conditions that may be developing. So, the transformer oil filtration machine is required to purify used transformer oil and keep the transformer oil absolutely clean.
Transformer oil received in drums must be stored on an elevated platform. A wide variety of transformer oil tester options are. 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. Oil to be tested is placed in a cell containing one pair of electrodes placed with a gap of 2. This test can give an early indication of abnormal behavior of the transformer. 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 consists of measuring breakdown voltage and other physical and. The dielectric strength of an oil still ranks as the most common field test.
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