Furan analysis and of testing of transformer oil powerlink. Transformer oil maintenance electric energy online. The gas space above the oil is filled with nitrogen. It evolved from the simple gonogo verdict into a sophisticated segment within transformer manufacturing. International standards define the test sequence and procedure of such a test. There are three basic styles used to transformer system voltages to control voltages. Through proper testing, the transformers lifespan is increased, reducing the need to pay for replacement.
Routine tests and type tests of transformers electrical4u. The different insulating materials have different dielectric strength. Neta is the leading source of specifications, procedures, testing, and requirements. Initial testing will establish a base line and annual testing will plot any changes happening internally in the transformer. The indicator generally shows the cold level when the oil is at a temperature of about 25 deg. The insulating material should sustain the voltage up to its dielectric strength. Testing standards and procedures are defined by various. Liquidfilled transformer instruction and maintenance manual.
A primary part of commissioning a transformer involves testing it after its installation in the field. Transformer oil testing by robert turcotte, manager, electrical loss control the hartford steam boiler inspection and insurance company the value of transformer oil testing transformer oil testing is a proven loss prevention technique which should be a part. Color d1500 the color of a new oil is generally accepted as an index of the degree of refinement. Insulation power factor testing of power transformers. The american society for testing and materials astm is the standard reference body used by. C the transformer should be tapped up as necessary with clean transformer oil. The megger guide to insulating oil dielectric breakdown. May 10, 20 so transformer ratio test is an essential type test of transformer. Jan 23, 2017 breakdown voltage bdv testing of transformer oil. The megger guide to insulating oil dielectric breakdown testing.
For oils in service, an increasing or high color number is an indication of contamination, deterioration, or both. If a proactive approach is adopted based on the condition of the transformer oil, the life of the transformer can be extended. Sep 24, 2017 with the help of transformer oil testing kit we can test transformer oil learn the process step by step. Before proceding with transformer measurements the test engineer will become familiar with the safety rules of section 2. Practice procedure of transformer oil sampling iec 60475 procedure of oil sampling in aluminum bottle the aluminum bottle is used for oil analysis in general and for analysis of compounds which are sensitive to light such as peroxide and furfural. To assess the insulating property of dielectric transformer oil, a sample of the transformer oil is taken and its breakdown voltage is measured. Transformer oil is a required addition to electrical transformers. The transformer installation position should be such that the breather, oil level indicator, rating and diagram plate, dial thermometers etc. This amounts to a rigorous examination of the transformer intended to.
These devices use standard transformer theory with 23 windings one primary with one or two secondary windings with a magnetic connection via an iron core. Transformer testing has developed considerably over the past years. Testing consists of measuring breakdown voltage and. Breakdown voltage of the transformer oils under certain conditions. Inspect transformer and parts for shipping damage and moisture. Transformer oil testing by robert turcotte, manager, electrical loss control the hartford steam boiler inspection and insurance company the value of transformer oil testing transformer oil testing is a proven loss prevention technique which should be a part of any conditionbased predictive maintenance program. Testing sequences and procedures are defined by various international standards, many of them set by astm. Tests at these two temperatures provides much more insight into the characteristics and quality of the oil encountered. The automatically generated report of the transformer oil testing sequence is available as a pdf version and is stored to the internal memory. When transformer is to be filled or topped off in the field, they must be filled under vacuum according to specific instruction. Remove shield from outlet sampling point 6 of a transformer.
Oil tests in the shop or laboratory would be carried out at room temperature 20o c as well as at an elevated temperature of 90o or 100o c. Testing of power transformers seems like a similar experience. In this book we have laid down important aspects on transformer. The lower the resulting breakdown voltage, the poorer the quality of the transformer oil. Because these generate a lot of heat that must be removed, they need to be insulated and they have to resist sparking, the physical and chemical properties of certain oils make them ideal for use in transformers and capacitors. This early warning system can allow management to identify maintenance priorities, plan work assignment schedules, and order necessary parts and materials. Development of an ongoing maintenance program will help prevent costly failures. Verify correct operation of transformer withdrawal mechanism and grounding operation. In this book we have laid down important aspects on transformer testing in order to enhance the understanding of the testing procedures and its outcome. The transformer oil is used in the transformer for insulation as well as for cooling purpose. 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. Testing potential transformers relay testing training. Bluetooth connection as means of communication with the instruments a usb flash drive interface and a bluetooth connection is offered.
Taking oil sample from power transformers dissolved gases astm d 3612, iec 60567, dissolved water astm d 1533, iec 60814 the following is one of the procedures to collect transformer oil sample. Transformer testing commissioning, routine, diagnostic. To prove that the transformer meets customers specifications and design expectations, the transformer has to go through different testing procedures in manufacturer premises. I and testing of oil as per specified standard is mandatory. Now lets move to, transformer oil purification procedure.
So for ensuring proper performance of electrical power transformer, voltage and turn ratio test of transformer one of the important tests. The international electrical testing association neta is an accredited standards developer for the american national standards institute ansi. With transformer oil this is done through testing of the oil. Power transformer testing procedures and schemes photo credit. 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. Sunbelt transformer liquidfilled transformer instruction and maintenance manual 3 4 internal inspection note. Transformer oil purification filtration processprocedure. The ac hv test value should not surpass 75% of the factory test value. There are many mineral oil filled transformers that have been in continuous use for more than 50 years. Identifies various gas ppm levels that are present in transformer insulating oil.
All of these oil types can be tested for dielectric breakdown voltage and tested with megger ots range test sets. Some transformer tests are carried out for confirming the basic design expectation of that transformer. Standard for acceptance testing specifications for electrical. If the oil level drops appreciably over a short period, the tank should be checked for leaks. When ac hipot tests are used for routine maintenance, the power transformer can be examined at rated voltage for 3 min instead of testing at 65% of factory test voltage. The following sections of the ansineta standard for acceptance testing specifications for. Astm d117 18 standard guide for sampling, test methods, and. 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. This ms excel spreadsheet is actually detailed instruction for each procedure necessary for correct testing of power transformer. The iec standard procedures used to test the insulating oil would introduce as.
Learn what transformer oil is, how to test transformer oil and the different types. The procedure of the transformer ratio test is simple. The are distinct advantages of testing and analyzing transformer oil before starting your electric power equipment and during scheduled maintenance events. Testing sequences and procedures are defined by various international. Following is an approximate sequence for transformer testing. The analytes remain on the stationary phase of the column with varying degrees of force due to the polar interaction. When predictive maintenance transformer and oil tests has disclosed a serious problem of moisture, combustible gas andor oil decay products, and on site purification is the chosen procedure the following steps are suggested. Regular sampling and testing of insulation oil taken from transformers is a valuable technique in a preventative maintenance pr ogram.
To ensure that the product is fit for its intended use standards iec standards iec 60076 part 1 part 14 specification for transformers ieee. The dielectric breakdown voltage is measured by applying a voltage between two electrodes under the oil. Specific transformer oil test method availability will vary depending upon location. Testing of oil in the field is typically limited to testing at whatever temperature. Routine testing of transformer oils and insulating oils on a regular schedule is an accepted industry. Transformer oil testing is a proven loss prevention technique that should be a part of any condition based predictive maintenance program. Despite the apparent superiority of naphthabased oil, paraffin oil remains the most commonly used type of oil in transformers worldwide. This test also performed as a routine test of transformer. Oil testing allows the operator to determine the equipments operating efficiency, conditions and the possibility of future malfunctions. Testing the condition and quality of transformer insulating oil provides data showing the actual condition of the transformer, and its remaining lifetime. Potential transformers pts or voltage transformers vts pts or vts are the most common device used. Periodic execution of oil tests also makes sense from an economic point of view, as.
Once power transformer is charged and commissioned, transformer oil becomes a key element to. Mineral oil is the most common insulating fluid and has been in use since the late 19th century. Section 7 of the ansineta standard for acceptance testing specifications for electrical power equipment and systems may be reproduced and used on a cut and paste basis for the particular type of equipment to be tested. When the pt is withdrawn ensure that there is no longer any connection with the primary electrical system. Power transformer testing procedures and schemes eep. Transformer oil test methods include astm, bs,and other recognized transformer oil analysis testing procedures. Regular sampling and testing of insulation oil taken from transformers is a valuable. 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.
New oil should have a minimum dielectric strength of 35 kv by astm methods of testing. The objective of testing is to ensure quality to ensure that the products manufactured have met the requirements of customer specificationstandard to prevent accidents which may occur if a failed product is put into service. For inservice equipment in particular, there are many test techniques for evaluating the condition of the insulating oil. Transformer oil testing quick, simple and onsite b2hv. Astm d117 18 standard guide for sampling, test methods. Only competent and qualified should open a sealed transformer. An internal inspection is necessary only if internal damage is suspected because of external indications of rough handling. Basics, maintenance, and diagnostics ix contents continued page 6. Pdf significance of transformer oil testing researchgate. Breakdown voltage bdv testing of transformer oil youtube. It is a good idea to remove all as a safety precaution to prevent backfeeding dangerous voltages into the system during testing. It should also be possible to have access to the operating mechanisms of the on load tap changeroff circuit tap switch, marshalling box etc. Standard for acceptance testing specifications for. One nettlesome aspect of electrical equipment that runs 24 hours a day, seven days a week is the need for continual testing and maintenance to ensure both safety and proper.
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