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Unformatted text preview: 21 Transformer Installation and Maintenance Alan C. Oswalt Consultant 21.1 Transformer Installation ................................................. 21-1 Receiving Inspection . Bushings . Oil Conservators . Gas Monitoring and Piping . Radiators . Coolers . Load Tap Changers (LTC) . Positive Pressure System . Control Cabinet . Accessories . Vacuum Cycle . Vacuum Filling System . Transformer Oil . Adding the Oil . Field Test 21.2 Transformer Maintenance............................................... 21-8 Maintenance Tests 21.1 Transformer Installation The first priority is to hire a reliable contractor to move and assemble the transformer. There are many stories where the contractors, lacking experience or proper equipment, drop the transformer or do not assemble the components correctly. Accepting a low bid could cost your company more than securing a competent contractor. Do not assume that all manufacturers have the same methods of installation. Your understanding of the manufacturers transformer installation book and reviewing the complete set of drawings in advance will help you to understand their procedures. Some manufacturers have a toll-free number which allows you to clarify drawings and = or the assembly methods. Others have put together a series of videos and = or CDs that will assist you to understand the complete assembly. Then you should review all of the information with your assembly contractor. 21.1.1 Receiving Inspection Prior to unloading a transformer and the accessories, a complete inspection is necessary. If any damage or problems are found, contact the transformer manufacturer before unloading. Freight damage should be resolved, as it may be required to return the damaged transformer or the damaged accessories. Photographs of the damage should be sent to the manufacturer. Good receiving records and photo- graphs are important, should there be any legal problems. Three important inspections checks are (1) loss of pressure on the transformer, (2) above zone 3 on the impact recorder, and (3) signs of movement by the transformer or its accessories. If any of the three inspection checks indicate a problem, an internal inspection is recommended. 2006 by Taylor & Francis Group, LLC. A shor ted core reading could also mean a bad transit ride. With a railroad shipment, if any of the checks indicate problems and an internal inspection does not reveal the problem, get an exception report filled out by a railroad representative. This repor t wi ll assist you later if hidden damages are found. Low core meggar readings (200 Megohms) could be an indication of moisture in the unit and require extra costs to remove. 1 The moisture could have entered the unit throug h a cracked weld caused by the bad transit ride. (See Figure 21.1 and Figure 21.2 .) Entering a unit requires good confined entr y procedures and can be done after contacting the manufacture, as they may want to have a representative present to do the inspection. Units shippedmanufacture, as they may want to have a representative present to do the inspection....
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- Spring '10