Iec 60422 largely depend on utilities own experience and expertise. Guidance for impulse testing of power transformers is given in iec 60722. Oil diagnostics transformer oil sampling sampling the transformers correctly is vital to ensuring an accurate oil result. A used oil having a high acid number indicates the oil is either oxidized or contaminated with materials such as varnish, paint or other foreign matter. 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. There are many mineral oil filled transformers that have been in continuous use for more than 50 years. The international electrotechnical commission iec is a worldwide organization for standardization comprising all national electrotechnical committees iec national committees. Iec 60422 versions moisture mg h 2 okg oil or ppm voltage kv.
This standard is applicable to mineral insulating oils, originally supplied conforming to iec 60296, in transformers, switchgear and other electrical apparatus where oil sampling is reasonably practicable and where the normal operating conditions specified. This manual describes general operation maintenance of 3phase two winding oil immersed distribution transformers manufactured according to iec bs standards. The effect of moisture on the breakdown voltage of transformer oil was investigated using a set of. All of these oil types can be tested for dielectric breakdown voltage and tested with megger ots range test sets. Seasonal influence on moisture interpretation for transformer.
Examination of the insulating oil by independent laboratory, reference list of users and certificate of the oil production in accordance with the standard iso 9001 will be considered as advantage. Transformer oil regeneration plant reoil 5000 ekofluid gmbh. Gray transformer chemistry services introduction the fault free operation of power transformers is a factor of major economic importance and safety in power supply utilities and industrial consumers of electricity. The oil treatment should ensure that all regulatory requirements are met see table 3 iec 60422 ed. Iec 60422 is a guide for the supervision and maintenance of mineral insulating oil in electrical equipment. Find the most uptodate version of iec 60422 at engineering360.
Iec 60422 mineral insulating oils in electrical equipment. Parameters indicating age of the oil inside the transformer such as acidity, tan delta and interfacial tension are significantly. In addition, aging of the transformer oil was simulated for. The megger guide to insulating oil dielectric breakdown testing.
Standard practices in transformer oil tangent delta. Test method iec 814 water, in minute quantities, is harmful in power equipment because it is attracted to the places of greatest electrical stress and this is where it is the most dangerous. The test procedure is performed in a specified apparatus, where the oil sample is subjected to an increasing ac electrical field until breakdown occurs. Transformer mineral oil, lifetime, degradation, arrhenius law. Astm d1500 color number the color of a new oil is generally accepted as an index of the degree of refinement. Divyol uninhibited transformer oil iec 60296 meeting iec 60296. This international standard is applicable to mineral insulating oils, originally supplied conforming to iec 60296, in transformers, switchgear and other electrical apparatus where oil sampling is reasonably practicable and where the normal operating conditions. Divyol uninhibited transformer oil meeting bs 148 class i. Reoil transformer oil regeneration regenerates transformer oils into like new condition fulfilling the requirement of iec 60422 standard. Transformer oils of other brands or add to oils in service, guidelines given in iec 60422 for maintenance of transformer oils in service, for both new oils and oils in service can be applied in general. The first revision was undertaken in 1978 to bring in line with the new oil requirements given in is 335. In this study, the electrical experiments and chemical tests were performed according to iec standard. This third revision has been aligned with iec 60422 1989 supervisionand maintenance guide for mineral.
Characteristics uni test method divyol iec 60296 uninhibited 1. Calibrating the result of dielectric measurements on field aged power transformers using oil analyses and similar measurements on welldefined pressboard samples c. There are a number of sampling methods used in the industry. International journal of innovative research in science. Thereafter, whenever there is a risk of potential contamination oil treatment, transformer repairs, etc.
Also the suggested test limits for reclaimed oil according to ansiieee std 6371985 are passed. Dielectric dissipation factor iec 60422 recommended action limits transformers recommended action limits o,a,b,c good. Water accelerates the deterioration of both the insulating oil and. Gives guidance on the supervision and maintenance of the quality of the insulating oil in electrical equipment. Temperature rise for liquidimmersed transformers iec 60156, insulating liquids determination of the breakdown voltage at power frequency test method iec 60247, insulating liquids measurement of relative permittivity, dielectric. This standard, revised and published in 20, is used. Ageing assessment of transformer insulation through oil test. The megger guide to insulating oil dielectric breakdown. The second revision was carried out to align with the corresponding iec 60422 1973. The tests on transformer oil shall be conducted in accordance with the relevant methods detailed in iec 60296 and shall fully comply with the provisions of this specifications. Transformer oil regeneration module reoil m enables complete renewal of used and old transformer oil onsite fulfilling the requirement of iec 60422 standard as well as corrosive sulfur removal.
This international standard is applicable to mineral insulating oils, originally supplied conforming to iec 60296, in transformers, switchgear and. This international standard gives guidance on the supervision and maintenance of the quality of the insulating oil in electrical equipment. The choice of a new mineral oil is guided by the iec 60296 standard. Reoil m equipment is designed as an add on module to work together with our transformer oil treatment filoil plants. Power transformers utilize oil as a heat transfer medium and a dielectric material, together with. Aging study and lifetime estimation of transformer mineral oil. Ideally the transformer oil should be changed when acidity approaches 0. If an oil not passing these new corrosivity tests is topped. It also meets the astm d 1275 b test requirement for corrosive sulphur sr. The small decrease in inhibitor content is likely to be. The characteristic and performance of the oil shall comply with the following. With overloaded transformers, the deterioration of materials is rapid and ift is a tool for detection of deterioration. Owing to the absence of oil temperature records, iec 60422. Detailed procedures for analyzing gas from gas spaces or gascollecting devices as well as gas dissolved in oil are described.
All bsi british standards available online in electronic and print formats. Transformer oil test parameters for ageing assessment 28, 80. The dryness and ageing state of the oil paper insulation is a key factor in both the short and long term reliability of a power transformer. In addition, iec 60422 includes only oil condition classification. Miscibility of apars transformer oils with other mineral oils and oils in service for mixing unused transformer oils of different grades of apar with unused transformer oils of other brands or add to oils in service, guidelines given in iec 60422 for maintenance of transformer oils in service, for both new oils and oils in. Mineral oil is the most common insulating fluid and has been in use since the late 19th century. Also, there exists doubt on the iec 60422 recommended values 11. And according to for iec 60422 standard for new oil insulation such as table 2 below 6.
To maintain the oil quality, periodic oil tests are performed and compared with the international standards 1, 2. Iec 60422, supervision and maintenance guide for mineral insulating oils in electrical equipment. In the standards, maximum water content limits are specified as mg of water per kg of transformer oil, i. Iec 60422 mineral insulating oils in electrical equipment iec 60422 mineral insulating oils in electrical equipment supervision and maintenance guidance 5 oil tests and their significance 5. This part of iec 60076 applies to liquidimmersed power transformers employing either hightemperature insulation or. This still holds true for the followup samples, taken after an average time of 7 months after treatment. Technical parameters of transformers are stated on the rating plate and in the factory routine test report. The dryness and ageing state of the oilpaper insulation is a key factor in both the short and long term reliability of a power transformer. Iec 60247, measurement of relative permittivity, dielectric dissipation factor and d. Testing of inservice insulating oil endeavour energy. Doble tops, doble transformer oil purchase specification.
This test serves as an indicator of the potential of the oil to form sludge. 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. Paper open access analysis of dielectric strength of virgin. C iec 60422 t able 2 categories of equipm ent categoryy type of equipment. Viscosity iec 60422 oil viscosity is an important controlling factor in the dissipation of heat. Appearance visual inspection of oil sample in transmitted light under a thickness of 10 cm. The latest version of iec 60422 is made in 20 as the improvement of the previous edition in 1973, 1989 and 2005 1214. Iec 60296 astm d 1524 fluids for electrotechnical applications unused mineral insulating oils for transformers and switchgear standard test method for visual examination of used electrical insulating oils of petroleum origin in the field 100ml purity membrane filter iec 60422, annex c. For this reason there are guides to follow to check the performance of the oil such as iec 60422 and ieee c57. 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. New oil insulation iec 60422 20 standard test parameters test parameters limits breakdown voltage 30 kv2,5mm viscosity oat 40 c 140 c water content transformer oil condition is refer to iec 60422 which classify the oil transformer conditions into three different conditions which are good, fair and poor based on its test parameters 11. Study on the treatment of high voltage used transformer oil by. However, it is vital to ensure that aging of the oil is not excessive and that it performs as it should 2.
Study on correlation among oil dielectric characteristics. Srcs transformer assessment package will tell you if. Sediments and soluble sludge in serviceaged insulating oils. The oil is subjected to a final filtration treatment, degassing and dehydration with a vacuum by continuously circulating it in a closed circuit. This standard is applicable to mineral insulating oils, originally supplied conforming to iec 60296, and used in transformers, switchgear and other electrical apparatus where oil sampling is reasonably. Pdf practice of iec 60422 in ageing assessment of in. A common reference for interpretation of oil test results is iec 60422, titled mineral insulating oil in electrical equipment supervision and maintenance guidance 11.
Iec 60422 is a guide for supervision and maintenance of mineral insulating oil in electrical equipment. The effect of moisture on the breakdown voltage of. Required characteristics and performance of the oil as per iec 60422. Condition monitoring of transformer oil using thermal analysis and.
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