The oil shall be thin enough to penetrate into narrow ducts and assist in the circulation through transformer winding to prevent local over healing. The bdv of oil in transformer is 60 kv1 min within the gap of 2. Adjust the electrode distance inside the oil cup with standard gauge. Testing sequences and procedures are defined by various international standards, many of them set by astm. The electrodynamics processes motivate an evolving ionizing electric. Breakdown voltage is measured by observing at what voltage, sparking strands between two electrodes immersed in the oil, separated by a specific gap. The positive li bdv test was conducted for both oil and developed nfs. The transformers oil shall be of low viscosity and shall offer the minimum resistance and maximum convective assistance to the flow. When transformer is to be filled or topped off in the field, they must be filled under vacuum according to specific instruction. Keeping the requirements of customers in mind, we keep providing latest and the most advantageous products for our customers. From my experience, untreated, raw transformer oil has to withstand 40 kv per 2.
Bdv tests is used to test the dielectric strength of the transformer. Transformer oil filtration system aditya engineers duration. The insulating material should sustain the voltage up to its dielectric strength. In the experiment proper, we considered only the acidity, whose concentration in the transformer oil increases with aging if the transformer, moisture, and a suitable impurity like naohaq. Predicted oil bdv size of testing set samples prediction accuracy 1 96. Requires 1 litre of oil in a polyethylene container. Transformer oil received in drums must be stored on an elevated platform. Transformer is one of the main asset in the electrical power industry which needs to be maintained for guaranteed uninterrupted power transmission in order to get assured revenue benefits. Specific transformer oil test method availability will vary depending upon location. Peaobdvmxxx automatic oil breakdown voltage tester features available in 100kv m100, 80kv m080 and 60kv m060 versions. Carry out the statutory transformer oil test onsite.
Overheating of the liquid insulation is a slightly different problem in transformers and can be on of transformer oil testing methods. Bdv test is an very important testing procedure for the insulation oils in transformer. The significance of the test it will detect free water, dirt and conductive particles. It is an optional component in high vacuum transformer oil filtration machine which is provided if the customer demands it. Basics, maintenance, and diagnostics ix contents continued page 6.
Dissolved gasin oil analysis the most important test that can be done on the liquid insulation of a transformer is an annual dissolved gas analysis dga. Mineral oil is the most common insulating fluid and has been in use since the late 19th century. Transformer oil used are normally tested using astm d87782 with the kv strength testing,using 1 electrode spaces 0. Lowcost manual instruments are still available, but think. The dielectric strength of transformer oil is also known as the breakdown voltage bdv of transformer oil. Once power transformer is charged and commissioned, transformer oil. We have nabl approved transformer oil test laboratory and render our service on short calls as and when required by you with our expert comments and suggestion promptly. Now lets move to, transformer oil purification procedure.
Using a combination of these diagnostic tests allows the oil to. A low value of bdv indicates presence of moisture content and conducting substances in the oil. The different insulating materials have different dielectric strength. Astm d1816 standard test method for dielectric breakdown voltage of insulating oils of petroleum origin.
Connect the earth terminal on the right side of the equipment to the earth wire firmly before start the equipment. 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. Due to the ultra fast voltage switchoff at flash over transformer oil testing of synthetic oil, ester oil and silicone oil is possible. Transformer oil analyst software, the fault condition of the transformer can be diagnosed. Parameters of transformer oil the parameters of transformer oil are categorized as, electrical parameters. 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, transformer will face some serious problems. Transformer oil purification filtration processprocedure. Transformer oil break down voltage bdv cr4 discussion. There are many mineral oil filled transformers that have been in continuous use for more than 50 years.
All of these oil types can be tested for dielectric breakdown voltage and tested with megger ots range test sets. Transformer spare part and transformer oil bdv test kit. Worlds only true bdv setmeasures hv secondary voltage across oil vessel electrodes, instead of across hv primary. Moulded test vessels give repeatable results with lock in precision electrode gap setting adjustment wheels. During filtration, temperature of oil must remain within 60. 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. Any failure to the transformer can extremely affect the whole functioning of the organization. Testing sequences and procedures are defined by various international.
The cleaned magnetic stirrer bar as dropped to the vessel so that it is placed at center. To determine dielectric strength, transformer oil is periodically tested by means of an oil punching apparatus. Before filling oil in transformer through filter machine, it has to be filtered separately in oil tanks and ensure bdv and ppm value. Insulating oil of transformers and current transformers fulfills the purpose of insulating as well as cooling. Various predefined and fully automatic test sequences meet all relevant international standards, thus the models of the ba series fulfill all legal requirements of the mandatory. Transformer oil test methods include astm, bs,and other recognized transformer oil analysis testing procedures. Break down voltage test of transformer oil duration. Based on the procedure above breakdown voltage of an oil sample is determined six times in a row and the. The miminum bdv for transformer oil in service is 30kv for 1 minute at an electrode gap of 2. The megger ots range of dielectric breakdown voltage test sets.
The vessel was cleaned thoroughly and filled with sample oil until the level is about 12mm from the top. During oil filling in the main tank of the transformer, it is preferable to connect the inlet hose pipe at the bottom of the tank. For measuring bdv of transformer oil, portable bdv measuring kit is generally available at site. If the technique of dissolved gas analysis is excluded, oil tests can be divided into two basic groups. Testing consists of measuring breakdown voltage and. A new transformer oil shol\uld have at least dielectric strength of 39 kv as per british standards. Routine testing of transformer oils and insulating oils on a regular schedule is an accepted industry. Meggers automatic laboratory oil test sets perform accurate breakdown voltage tests on mineral, ester and silicon insulating liquids. To test the oil sample, transformer oil is poured into a porcelain vessel in which two disk electrodes, one of 8mm diameter and one of 25mm diameter, are mounted.
The dielectric strength of an oil still ranks as the most common field test. The middle layer is a processing device which process the. Pdf significance of transformer oil testing researchgate. The megger guide to insulating oil dielectric breakdown testing. All data can be downloaded either as adobe pdf or in text format by email for import into the delta x transformer oil analyst program, or databases such as. Ots100af, ots80af and ots60af laboratory oil testers. After filling the oil up to the top of the transformer core, maximum suitable vacuum is maintained above the oil level in the tank to minimize the hazard of bubbles lodging in the inaccessible corners of winding. In this kit, oil is kept in a pot in which one pair of electrodes are fixed with a gap of 2. The mounted electrodes were separated from the container. Low value of bdv indicates presence of moisture content and conducting substances in the oil. In general, the solubilities and thermal decomposition products of beta fluid are very similar to those from conventional transformer oil.
From the experiments, the heating procedures resulted in the production of toxic gases. Testing consists of measuring breakdown voltage and other physical and. For measuring bdv of transformer oil, bdv measuring kit is used. The transparent, shielded lid and large test chamber enable easy access to the test vessel. The transformer oil is used in the transformer for insulation as well as for cooling purpose. Pdf dielectric strength measurement is the most primitive test which decides the health of. Transformer oil reservoir must be under positive pressure. Pdf development of an automated break down voltage test set. Nabl accrediated transformer oil testing lab transformer oil test labnabl nabl accredited testing laboratory as per isoiec 17025. Keywordsautomation using arduino, oil breakdown voltage. The megger guide to insulating oil dielectric breakdown. This test can give an early indication of abnormal behavior of the transformer. Keywordsautomation using a rduino, oil breakdown voltage. Your test results are well above the mimimum requirement.
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