Npm services offers a full line of transformer diagnostic tests to determine the integrity and serviceability of insulating fluids. Liquidfilled transformer instruction and maintenance manual. If the transformer loses pressure again with no change in temperature sunbelt transformer should be contacted immediately. Clornoil 50 test kit in order to classify them as either pcb or nonpcb i.
Test parameters transformer oil testing laboratory nabl. Degasification, insulating oil, moisture, purification, 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. Our distribution transformer test system dtts has been designed with these requirements in mind, as a multifunctional tool for testing distribution transformers. How can we test electrical insulation of transformer oil. Each piece of equipment was te sted once with the test kit. A random sample of 937 of the clornoil negatives were tested by gas chromatography to confirm the results. 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 ultimate starting point for any transformer assessment is the oil analysis. Testing sequences and procedures are defined by various international.
From the test results it shall be identified that acidity content is high for degraded oil. Any improved preventive maintenance procedures should help extending their life. 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. 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. So, insulation overheating measurement is also transformer oil testing methods. What is the bdv breakdown voltage of a 33kv transformer. Remove shield from outlet sampling point 6 of a transformer. Power transformer oil test results must be recorded in the ms access database at g. 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. 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. Coconut oil as an alternative to transformer oil pdf. 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. Transformer oil sampling procedure for laboratory oil analysis, dga dissolved gas analysis and oil quality analysis pt. 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.
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. 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. Transformer and oilfilled reactor installation procedure sp. Some transformer oil tests can be carried out in the field, using portable test apparatus. The collection of transformer oil samples according to the following procedure for d. A wide variety of transformer oil tester options are available to you, such as usage, power.
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. Dnv gl provides independent oil laboratory services covering sampling, analysis and interpretation. The objective is to get as much of the old oil out as possible. Study of transformer oil purification ssrgjournals.
Also information about some types of transformers are gathered as well as distribution transformer connections installations. The acidity level of transformer oil is measured as per british standard bs2000 part 1. What links here related changes upload file special pages permanent. 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. Connect the earth terminal on the right side of the equipment to the earth wire firmly before start the equipment. All the test results, including test equipment print outs and manual records, must be maintained for future reference. In comparison with hvdc transformer test and service conditions todays standard measuring procedure for oil conductivities is performed both with very short. Mineral oil is the most common insulating fluid and has been in use since the late 19th century. 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. 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. Dissolved gas analysis is the single most important test performed on oils from transformers. Insulating oil testers bdv test of transformer oil. Transformer oil testing sequences and procedures are defined by various international standards.
Bdv testing is done to test break down voltage of transformer oil. Like blood testing in human beings, its an essential indicator of good health. Figure vt polarity test transformer turns ratio test a variable ac source is applied on the primary side. Oil testing capabilities doble engineering company. For the purpose of bdv test, oil sample from transformer is taken in a sample bottle. The test is performed as per astm d3359 standard test methods for measuring adhesion by tape test. Effect of dbds and dbpc on paper oil insulation of power. Transformer oil analysis bureau veritas commodities. If everything checks out, drain the transformer oil. Depending on the oil, there can be tens to hundreds of different sulfur compounds present in the oil. What is the minimum value of breakdown voltage of transformer oil. Bdv test is an very important testing procedure for the insulation oils in transformer.
The transformer should be pressurized with 24 psi positive pressure of 99. Dissolved gas analysis of transformer oil electrical4u. Jul 17, 2017 test the transformer insulation and look for signs of shorts or damaged windings. For measuring bdv of transformer oil, bdv measuring kit is used. It creates an acceptable level of insulation and also acts as a coolant to extract heat from the core and the windings. Transformer oil reservoir must be under positive pressure. Transformer oil testing is a cornerstone of an asset management program. 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.
Adjust the electrode distance inside the oil cup with standard gauge. Apr 23, 2018 transformer oil sampling procedure for laboratory oil analysis, dga dissolved gas analysis and oil quality analysis pt. Transformer oil testing laboratory nabl accreditated. 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. Destruction of dibenzyl disulfide in transformer oil lance. Same nine samples were investigated for acidity value by means of.
Transformer oil breakdown voltage testing procedure. Tests at d and e may be carried out on more than one unit subject. Transformer oil analysis provides a highly accurate indication of the internal condition of a transformer. Our transformer oil analysis lab can is capable of conducting the following tests. Power transformers undergo prolonged drying processes, using electrical. Whenever a transformer undergoes abnormal thermal and electrical stresses, certain gases are produced due to the decomposition of the transformer oil. About 78% of these are testing equipment, 8% are other test instruments. When transformer is to be filled or topped off in the field, they must be filled under vacuum according to specific instruction. The results from the testing are summarized in table 4.
The gap between the test electrodes sample to be 2. Transformer design drytype and cast resin, protection methods are being referred and more also included in the specific research document. Transformer and insulating oils are subject to electrical and mechanical stresses while a transformer is. Replace the transformer drain plug and refill the unit with fire.
Also there is detailed analysis about the consisting of a distribution transformer. Take sample from top of transformer before filtration. The pdf of transformers oil test is a very good file for you. Dissolved gas analysis dga is the study of dissolved gases in transformer oil. Oil to be tested is placed in a cell containing one pair of electrodes placed with a gap of 2.
In this paper, we will study about the transformer oil filtration machine and how it purifies the contaminated transformer oil. Transformer oil testing quick, simple and onsite b2hv. 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. Before attempting to draw the sample identify the type of cooling liquid in the transformer. If this is not possible, the transformer has to be placed in a dry place and the transformer must be filled with oil. The standard test suites are designed for individual samples to deliver a routine set of oil analysis at low. The primary and secondary voltages are measured to determine the ratio v2v1 reference.
Once the oil is drained, proceed with flushing out the inside of the transformer. 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. The transformer oil testing device measures and reports the root mean square value of the breakdown voltage. Bdv means breakdown voltage, also named as dielectric strength valve. The megger guide to insulating oil dielectric breakdown testing. As the insulating materials in a transformer break down due to thermal and electrical stresses, gaseous byproducts are formed. On transformer oil break down voltage test is carried out which is done on field while filling the oil in transformer. The oil used in transformers is hydrocarbon mineral oil. If regularly conducted, oil analysis allows identification of specific fault conditions that may be developing. The byproducts are characteristic of the type of incipientfault condition. The above standard testing is offered in specific diagnostic suites designed to provide the maximum condition information on the transformers. Transformer oil or insulating oil is an oil that is stable at high temperatures and has excellent.
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