Transformer oil testing for dielectric strength vessel preparation and elimination of the effects of moisture and contamination play a major role in successful oil testing. Oil test kit with semi hv transformer circular electrodes 220v100kv single phase auto transformer single phase 220v ac supply fig. Reverse side of card at right is used to record the test data. 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.
Dnv gl provides independent oil laboratory services covering sampling, analysis and interpretation. Here we are explaining about transformer oiil filteration procedure and how it is done. The global transformer oil market size was estimated at usd 1. Once the oil is drained, proceed with flushing out the inside of the transformer. The acidity level of transformer oil is measured as per british standard bs2000 part 1. Figure 3typical scale on the megger insulation tester. Transformer testing, transformer oil analysis lab, transformer oil test lab, oil transformer test sl no. A useful tool to support the decisionmaking process in power transformer management is risk assessment. How to take transformer oil break down voltage test. Transformer oil also known as insulating oil is a special type of oil.
If regularly conducted, oil analysis allows identification of specific fault conditions that may be developing. Acidity accelerates the oxidation process in the oil. Therefore the studies of discharge processes in oil. Testing sequences and procedures are defined by various international. International standards define the test sequence and procedure of such a test. Methyl methacrylate vessel with effective volume between 300 to 500 ml. It is done for checking the dielectric strength of the oil of the transformer. Installation and maintenance instructions for liquidfilled distribution transformers 5 version 4 01082010. The oil samples should preferably be taken in the moving.
The ultimate starting point for any transformer assessment is the oil analysis. Hartford steam boiler uses test results in its transformer oil gas analyst toga program, for instance, to diagnose transformer problems. This test shows the dielectric strength of transformer oil. If everything checks out, drain the transformer oil. The megger guide to insulating oil dielectric breakdown. Product information dissolved gas analysis and supervision. Transformer oil is widely used as an insulator in various highvoltage machineries. Testing sequences and procedures are defined by various international standards, many of them set by astm. Service contract for carrying out the transformer oil. Is 1180 outdoor distribution transformer up to and including 100 kva is 12444 specification for copper wire rod astm b49 is335 specification for transformer oil bs 148, d1473, d15331934 iec pub 296 is 5 specification for colors for ready mixed paints is. The dga test measures dissolved gases in the transformer oil and is capable of detecting. If so, inform the manufacturer of these irregularities before starting any repair. To achieve this, remove the plug from the drain valve and drain approximately onehalf to one litre of oil into an oilwaste container. It was found that the inception voltage remained but the.
Please refer to the addendum for an explanation of the doble ccd test. Performance of natural ester as a transformer oil in moisturerich environments. Megger leads to be connected to lv and hv bushing studs to measure insulation resistance ir value in between the lv and hv windings. Connect the earth terminal on the right side of the equipment to the earth wire firmly before start the equipment. A practical method for risk assessment in power transformer fleets1. At first thing you maintain the electrical normsto take one sample from top of transformer and one from the bottom of transformer. Dissolved gas analysis of transformer oil electrical4u.
The objective is to get as much of the old oil out as possible. Generally applicable conditions we are delighted that you have purchased a cg power systems transformer. Results and discussions leakage current measurement for clean oil, oil with dbds and oil with dbpc at different concentrations are tabulated and graphically shown. When the fault is major, the production of decomposed gases are significant and they get collected in a buchholz relay. The different insulating materials have different dielectric strength. Test the transformer insulation and look for signs of shorts or damaged windings. Guide for field pd tests for liquidfilled power transformers. 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. The test cell shall be of glass or plastic and transparent and nonabsorbent eg. Adjust the electrode distance inside the oil cup with standard gauge.
Samples are generally sent to a laboratory for analysis but portable equipment is available to perform the. Power transformer diagnostics, monitoring and design. Curve b shows same values corrected to 20c see page 22, giving a definite downward trend toward an unsafe condition. Like blood testing in human beings, its an essential indicator of good health. Internal and external state of health of transformer. Testing consists of measuring breakdown voltage and. Gases generate by degradation of fluid or cellulose.
Pcb is very stable and its degradation process is slow, it is also. 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. 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 transformer oil under test is subjected to an ac electric field with continuously increasing voltage till the oil breaks down. A new transformer oil shol\uld have at least dielectric strength of 39 kv as per british standards. Oils that combine a high flashpoint with high dielectric strength have long been. Abbs mobile transformer oil processing service will restore the performance and extend the service life of any make of oilfilled transformer. Regular sampling and testing of insulation oil taken from transformers is a valuable technique in a. The megger guide to insulating oil dielectric breakdown testing. Oil testing has found widespread use in assessing the quality of the insulation system of a. The transformer s fluid not only serves as a heat transfer medium, it also is part of the transformers insulation system. It was manufactured using the latest techniques, tested in full and subjected to a thorough final inspection before delivery.
Dissolved gas analysis dga is the study of dissolved gases in transformer oil. The complete guide to electrical insulation testing. A free and open source software to merge, split, rotate and extract pages from pdf files. Heating and filtering of insulating transformer oil and filling shall be performed as per manufacturer s recommendations. This test can give an early indication of abnormal behavior of the transformer. During sampling, a small amount of mineral oil is withdrawn from the transformer and analyzed for dissolved gases, moisture and breakdown of cellulose products. Regular purification will increase breakdown voltage to required level. Same nine samples were investigated for acidity value by means of. A press type or a cartridge type filter is generally used. Stagnant oil from the lower drain valve of the transformer must be removed before the sample is collected. The gas space above the oil is filled with nitrogen that could cause asphyxiation or death.
Replace the transformer drain plug and refill the unit with fire. Learn what transformer oil is, how to test transformer oil and the different types and properties. Periodic execution of oil tests also makes sense from an economic point of view, as. Figure 4typical record of insulation resistance of a mill motor. For measuring bdv of transformer oil, bdv measuring kit is used. Installation and maintenance instructions for liquid. As the name implies, this test analyzes the type and quantity of gases that are dissolved in the transformer oil. Liquidfilled transformer instruction and maintenance manual. Oil sample collecting techniques transformer oil testing. Detects most internal faults, some external faults and some operational errors. In the process of purification water, dirt, and gasses are removed from power transformer oil. The pdf document api component allows you to merge multiple pdf.
Transformer oil filtration procedure here in this article you will understand about how a transformer oil purification process is done, its steps and methods involved in oil purification process. The oil filter must be capable of removing dirt and moisture from the 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. A transformer oil carries information about the condition of the transformer. The oil filter is used for filling oil into the oil storage tank from drums or tank lorry and pulling oil inout between the oil storage tank and transformer. Test parameters test method ref standard 01 interfacial tension ring method is. Bdv tests is used to test the dielectric strength of the transformer. Oil to be tested is placed in a cell containing one pair of electrodes placed with a gap of 2.
When lifting the transformer, the suspension cables have to be maintained almost. From the test results it shall be identified that acidity content is high for degraded oil. Transformer oil breakdown voltage testing procedure. Transformer oil market size, share global industry. This application note points to the precautions that need to be taken. Insulation oil treatment and its necessity in power.
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. Dielectric strength means the maximum capacity to withstand voltage of insulating oil. The electrical properties of oil can suddenly change due to changes in oxidation, acids, sludge gas and even water absorption, so. Transformer oil sampling abbs service engineers have been trained in the strict routines needed to obtain a clean sample to bs 5263 just as a blood test provides a doctor with a wealth of information about the health of a patient, a sample of transformer oil, taken correctly, can tell service engineers a great deal about the condition of a. Expansion in the power sector to meet growing electricity requirements has driven significant progress in the transformers industry. 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. Merge documents office file api devexpress documentation. The insulating material should sustain the voltage up to its dielectric strength.
Transformer oil analysis provides a highly accurate indication of the internal condition of a transformer. Whenever a transformer undergoes abnormal thermal and electrical stresses, certain gases are produced due to the decomposition of the transformer oil. Ddf test procedure uses alternating current, but the two properties are related though not with such precision as would permit really accurate interconversion by means of a formula. Effect of dbds and dbpc on paper oil insulation of power. Also moisture that may be present in the depression of the drain valve must be removed. On before take oil samples you should confirm the moisture particles removed are not.
It is an optional component in high vacuum transformer oil filtration machine which is provided if the customer demands it. The procedure of the insulation resistance test are given below first, disconnect all the line and neutral terminals of the transformer. Mineral oil is the most common insulating fluid and has been in use since the late 19th century. The oils purpose is to insulate internal electrical components, suppress corona discharge and arcing, and serve as a coolant to draw heat away from the core of the transformer. The transformer oil is used in the transformer for insulation as well as for cooling purpose. Transformer condition monitoring transoil laboratory.
1 412 927 25 1447 79 363 489 404 823 1224 521 335 304 1512 492 665 1006 1345 413 805 799 1205 531 714 850 185 939 1101 418 125 976 1215 1103