Transformer oil purchase specification test limits type of test notes astm method type i uninhibited inhibited type ii. If this is not possible, the transformer has to be placed in a dry place and the transformer must be filled with oil. Thus, the dielectric quality of transformer oil is essential to secure operation of a transformer. For over 100 years, megger has been a world leader in the development and manufacture of test equipment for electrical power applications. Power transformer oil sampling job safety analysis. Excessive or prolonged skin contact with transformer oil mineral oil should be avoided. These points are discussed next under installation, maintenance and transformer testing. Field testing of fluidfilled power transformers, regulators, and reactors. A larger quantity of oil is needed for these tests. Liquid filled transformer applications music city power quality conference august 2, 2016. A 40yearold transformer showed a degree of polymerization of 260 in early 2010 during testing, with estimated remaining life at 19 percent. The sfl is the number of hours the oil remains sludgefree. Gases generate by degradation of fluid or cellulose.
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. A form of ac testing that applies voltage and measures the leakageloss current of electrical insulation. The priciples of routine, type and special tests are however. An indepth analysis of your transformer s oil gives you a good insight into the condition of your transformer and its electrical insulation. One must assure that the test cell is clean and it is a wise precaution to bleed the sampling tube to assure a representative sample. Testing of power transformers seems like a similar experience. The procedure of the transformer ratio test is simple. 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. Transformer testing has developed considerably over the past years. The water content oil samples were taken at the bottom of the transformer, whereas the water after vacuum samples were drawn at a sampling point at the outlet of the cjctm unit. Testing power transformers test procedures and equipment used for the testing of large power transformers at abb oy, power transformer, vaasa works are dealt with in the following sections. Furfural analysis has been proved a useful tool for the aging diagnosis of solid insulation in large oil immersed power transformers. Transformer oil test methods include astm, bs,and other recognized transformer oil analysis testing procedures. Thus the utilities need to keep a track of the health of the transformer and also develop a diagnosis system.
Oil samples should, therefore, be allowed to settle for 4 to 6 hours in case of small transformer or drums, and for 10 to 12 hours in case of large transformer. The power factor test is widely used as an acceptance and preventive maintenance test for insulating oil. Most popular offline test is the power factor test detects when oil gets contaminated by carbon from pd in oil or paper or water. The below are test results from a transformer unit at the copenhagen light and power company. 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. These tests include dielectric breakdown, power factor, interfacial tension, acidity, and color. Understanding the value of electrical testing for power.
Drytype power transformers installation factors that need to be clearly kept in mind when installing drytype transformers are. Transformer and insulating oils are subject to electrical and mechanical stresses while a. Routine testing of transformer oils and insulating oils on a regular schedule is an accepted industry. Standard for acceptance testing specifications for. The following sections of the ansineta standard for acceptance testing specifications for. Transformer plays a vital role in the power system as it acts as. With transformer oil this is done through testing of the oil. Pdf significance of transformer oil testing researchgate.
This test also performed as a routine test of transformer. Page 2 of 8 reference sp0504r01 ver 1 reference owner. Some of them are even batterypowered and come with accessories. The transformer was immediately taken offline and internally inspected to identify any problems.
Monophase transformer turns ratio unit, from megger company, model ttr100 the really important fact is to know the status and evolution of the transformer to be in conditions to operate it with the maximum security and know if it is appropriate to continue its use, know overload. 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. Their availability and longevity have a major impact on grid reliability and profitability. The screen test is a collection of physical, electrical and chemical transformer oil testing methods. The transformer testing performed before commissioning the transformer at the site is called the precommissioning test of the transformer. Oil filled transformer pd testing online pd usually measured by acoustic sensors, by. Detects most internal faults, some external faults and some operational errors.
The dielectric strength of an insulating oil is a measure of the oils ability to withstand electrical stress without failure. So transformer ratio test is an essential type test of transformer. Development of an ongoing maintenance program will help prevent costly failures. Neil dwyer, manager technical services ergon energy corporation limited abn 50 087 646 062 ergon energy queensland pty ltd abn 11 121 177 802 key tools and equipment. Oil tests in the shop or laboratory would be carried out at room temperature 20o c as well as at an. The ac hv test value should not surpass 75% of the factory test value. Ppt transformer tests powerpoint presentation free to. Abbs power transformers are key components in power networks. Page 2 of 14 standard work practice sp0504 ver 4 ergon energy corporation limited abn 50 087 646 062 ergon energy queensland pty ltd abn 11 121 177 802 sm0701. Deteriorated insulation and ageing are the two major causes of incipient faults. Powerfactor or dissipationfactor tipup exceeding 1. The transformers are divided into dry and liquid types for the purposes of this course.
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. Distribution transformers maintenance guide for liquid. Wait until 24 hours after completion of oil filling for power factor testing. We ensure that every one of our 20,000 delivered units has undergone rigorous fullacceptance testing. Water and water saturated oil are both heavier than dry oil and sink to the bottom of any container. Testing of transformer or insulating oil 1 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. Transformer breakdowns usually cause power outages and. Oil sampling and analysis north vancouver facility we are pleased to submit the insulating fluid report and test sheets for the three 3 transformers and one 1 ocb located at the north vancouver facility. 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. Oil power factor testing in the field is usually done with the doble type mh or m2h test set in conjunction with power factor tests of the oil filled equipment. Mineral oil is the most common insulating fluid and has been in use since the late 19th century. The insulation oil used in power transformers is a combination of liquid transformer oil and solid impregnated cellulose. Mlgw began to test each of its transformers for furans in 2009. Alarm, control, and trip circuits from temperature and.
Transformer oil analysis bureau veritas commodities. Power transformer testing swp check this is the latest process zone version before use. In addition to the above transformer testing methods, the power transformer also goes through some other tests, performed on it, before the actual commissioning of the transformer at the site. So for ensuring proper performance of electrical power transformer, voltage and turn ratio test of transformer one of the important tests. Steel itself is a conductor, and changing lines of magnetic flux also induce a voltage and current in this conductor. The megger guide to insulating oil dielectric breakdown testing. In this book we have laid down important aspects on transformer. Impedance dc winding resistance megger and power factor windings, bushing and arrestors. Transformer oil analysis provides a highly accurate indication of the internal condition of a transformer. Job safety analysis power transformer testing check this is the latest process zone version before use. Field testing of fluidfilled power transformers, regulators, and reactors ieee std 57.
Vasantha gowri and zainab akthar chaitanya bharathi institute of technology, hyderabad, india abstract failure in power transformer can be catastrophic to electric systems, since transformers play a vital role in the power sector. Preventing transformer failure is vital to the safe and reliable operation of any electrical network. Specific transformer oil test method availability will vary depending upon location. Transformer oil also known as insulating oil is a special type of oil which has excellent electrical insulating properties and is stable at high.
The value of transformer oil testing transformer oil testing is a proven loss prevention technique which should be a part of any condition based predictive maintenance program. Transformer oil maintenance electric energy online. For further information regarding oil handling, please refer to ewect of mineral oil on the skin shw295 a list of standards applicable to distribution transformer is given as below. A time series analysis based data tendency prediction method for dissolved gas production monitoring in power transformer oil zhang wei1, wu rongrong2, pu jinyu3, deng yurong4 changing rules of time series in data of dissolved gas production produced by power transformer insulation oil monitoring are studied based on mathematical statistics. Recently timeconsuming testing procedures in test labs irc been replaced by onsite oil testing procedures. The megger guide to insulating oil dielectric breakdown. Turnsratio test results should not deviate more than onehalf percent from either the adjacent coils or the calculated ratio. Uptonow, diagnostic criteria for operating transformers are.
Ansineta mts2015, standard for maintenance testing specifications for electrical power equipment and systems. Measurement technology and power electronics designed for long service life. Most of the electric power utilities adopt regular analysis of insulating oil samples as a basic requirement of transformer maintenance program. Initial testing will establish a base line and annual testing will plot any changes happening internally in the transformer. The typical excitation current test data pattern for a. Power transformer maintenance and field testing on photo. It evolved from the simple gonogo verdict into a sophisticated segment within transformer manufacturing. The growing power demand leads to the manufacturing of a large number of oil immersed transformers and other electrical equipment.
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