The transformer oil testing device measures and reports the root mean square value of the breakdown voltage. Transformer and oilfilled reactor installation procedure sp. How can we test electrical insulation of transformer oil. Dissolved gas analysis dga is the study of dissolved gases in transformer oil. The primary and secondary voltages are measured to determine the ratio v2v1 reference. Npm services offers a full line of transformer diagnostic tests to determine the integrity and serviceability of insulating fluids. Oil diagnostic suites for transformer oil diagnostics. All the test results, including test equipment print outs and manual records, must be maintained for future reference. Remove shield from outlet sampling point 6 of a transformer. The bdv test of transformer oil has a breakdown time of less than 10 milliseconds, a rise rate of voltage is 2 kv per second, and the kv indication appears in three digits. What is the minimum value of breakdown voltage of transformer oil. Destruction of dibenzyl disulfide in transformer oil lance.
Study of transformer oil purification ssrgjournals. If the transformer loses pressure again with no change in temperature sunbelt transformer should be contacted immediately. Bdv testing is done to test break down voltage of transformer oil. The pdf of transformers oil test is a very good file for you. After a transformer has been received at its final destination, it is advisable to put it full of oil on its permanent place, even if it is not going to be placed in operation immediately.
On transformer oil break down voltage test is carried out which is done on field while filling the oil in transformer. 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. The megger guide to insulating oil dielectric breakdown testing. Test parameters transformer oil testing laboratory nabl. Transformer oil analysis provides a highly accurate indication of the internal condition of a transformer. Liquidfilled transformer instruction and maintenance manual. Transformer oil testing quick, simple and onsite b2hv. For a high voltage pulse power supply of 140kv amplitude, rise time 1usec, fall time 1usec, pulse width 6 usec and prf is 10 hz. A random sample of 937 of the clornoil negatives were tested by gas chromatography to confirm the results. 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. The byproducts are characteristic of the type of incipientfault condition.
Transformer oil analysis bureau veritas commodities. Transformer oil testing laboratory nabl accreditated. Transformer oil sampling procedure for laboratory oil analysis, dga dissolved gas analysis and oil quality analysis pt. Replace the transformer drain plug and refill the unit with fire. Testing sequences and procedures are defined by various international. Degasification, insulating oil, moisture, purification, transformer. Transformer design drytype and cast resin, protection methods are being referred and more also included in the specific research document. A wide variety of transformer oil tester options are available to you, such as usage, power. 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. Bdv means breakdown voltage, also named as dielectric strength valve.
Some transformer oil tests can be carried out in the field, using portable test apparatus. Transformer oil breakdown voltage testing procedure. Transformer oil testing is a cornerstone of an asset management program. Introduction there is not one single corrosive sulfur compound that is responsible for all corrosive sulfur issues that are present in all mineral oil filled electrical apparatus. 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. Any improved preventive maintenance procedures should help extending their life. The acidity level of transformer oil is measured as per british standard bs2000 part 1. What is the bdv breakdown voltage of a 33kv transformer. What links here related changes upload file special pages permanent. The user defined settings in this tester include calendar, sample number, stirring time and the number of tests is settable from 1 to 9 times. The oil used in transformers is hydrocarbon mineral oil. It creates an acceptable level of insulation and also acts as a coolant to extract heat from the core and the windings. After the transformer oil test is completed, the insulation oil is stirred automatically and the test sequence is performed repeatedly.
Mineral oil is the most common insulating fluid and has been in use since the late 19th century. For measuring bdv of transformer oil, bdv measuring kit is used. Same nine samples were investigated for acidity value by means of. Transformer and insulating oils are subject to electrical and mechanical stresses while a transformer is. Going by knowledge and experience in this industry, i think here the question pertains to the break down voltage of transformer oil because on field or on papers whenever bdv of transformer is mentioned it is actually the. 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. Like blood testing in human beings, its an essential indicator of good health.
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. Bdv test is an very important testing procedure for the insulation oils in transformer. Effect of dbds and dbpc on paper oil insulation of power. In this paper, we will study about the transformer oil filtration machine and how it purifies the contaminated transformer oil. The standard test suites are designed for individual samples to deliver a routine set of oil analysis at low. Coconut oil as an alternative to transformer oil pdf. Dissolved gas analysis of transformer oil electrical4u. Oil to be tested is placed in a cell containing one pair of electrodes placed with a gap of 2. Transformer oil testing sequences and procedures are defined by various international standards. When transformer is to be filled or topped off in the field, they must be filled under vacuum according to specific instruction. The above standard testing is offered in specific diagnostic suites designed to provide the maximum condition information on the transformers. 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. Transformer oil or insulating oil is an oil that is stable at high temperatures and has excellent. The gap between the test electrodes sample to be 2.
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. If regularly conducted, oil analysis allows identification of specific fault conditions that may be developing. In comparison with hvdc transformer test and service conditions todays standard measuring procedure for oil conductivities is performed both with very short. Also there is detailed analysis about the consisting of a distribution transformer. Jul 17, 2017 test the transformer insulation and look for signs of shorts or damaged windings. 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. Apr 23, 2018 transformer oil sampling procedure for laboratory oil analysis, dga dissolved gas analysis and oil quality analysis pt. If everything checks out, drain the transformer oil. The collection of transformer oil samples according to the following procedure for d. As the insulating materials in a transformer break down due to thermal and electrical stresses, gaseous byproducts are formed. Dissolved gas analysis is the single most important test performed on oils from transformers. The ultimate starting point for any transformer assessment is the oil analysis. Contract specific procedure for testing of electrical equipment and 2kv ohl source. Our transformer oil analysis lab can is capable of conducting the following tests.
Power transformer oil test results must be recorded in the ms access database at g. Insulating oil testers bdv test of transformer oil. The test is performed as per astm d3359 standard test methods for measuring adhesion by tape test. The objective is to get as much of the old oil out as possible. Oil testing capabilities doble engineering company. While taking sample of oil from transformer, sample bottle should be flushed well by transformer oil and oil in sample bottle should be vented properly so that atmospheric moisture could not ingress in the sample oil. Take sample from top of transformer before filtration. Due to the ultra fast voltage switchoff at flash over procedure using wellprepared sequences and minimal manual intervention to keep the test duration of a single transformer as short as possible and to avoid human errors. So, insulation overheating measurement is also transformer oil testing methods. Our distribution transformer test system dtts has been designed with these requirements in mind, as a multifunctional tool for testing distribution transformers. Tests at d and e may be carried out on more than one unit subject. Connect the earth terminal on the right side of the equipment to the earth wire firmly before start the equipment.
Clornoil 50 test kit in order to classify them as either pcb or nonpcb i. The transformer should be pressurized with 24 psi positive pressure of 99. If this is not possible, the transformer has to be placed in a dry place and the transformer must be filled with oil. From the test results it shall be identified that acidity content is high for degraded oil. Figure vt polarity test transformer turns ratio test a variable ac source is applied on the primary side. Dnv gl provides independent oil laboratory services covering sampling, analysis and interpretation. Procedures for drawing transformer oil samples general sampling electrical insulating oil for laboratory analysis requires care to ensure that the sample is representative of the product being sampled. Each piece of equipment was te sted once with the test kit. Also information about some types of transformers are gathered as well as distribution transformer connections installations. Once the oil is drained, proceed with flushing out the inside of the transformer.
Depending on the oil, there can be tens to hundreds of different sulfur compounds present in the oil. Whenever a transformer undergoes abnormal thermal and electrical stresses, certain gases are produced due to the decomposition of the transformer oil. The results from the testing are summarized in table 4. Adjust the electrode distance inside the oil cup with standard gauge. About 78% of these are testing equipment, 8% are other test instruments. This test method is to determine the degradation of cellulose paper insulation high concentration or unusual increase in the concentrations of furanic compounds in oil may indicate cellulose degradation from aging or incipient fault conditions the levels of furanic compounds in oil relate to the average deterioration of the insulating. The transformer oil performs two important functions. Power transformers undergo prolonged drying processes, using electrical. Transformer oil reservoir must be under positive pressure. Purification of transformer oil transformer oil purification is a process to remove.
989 80 1300 544 47 530 818 95 1470 485 632 1255 533 1101 933 11 275 1552 1644 1221 502 936 1003 417 634 584 519 408 933 219 1095 1059 260 201 358 733 1259 1153 199 1031