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Transformer Riddle No.31 – Enhancement of 20MVA to 25MVA

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  • #377
    A.Selvakumar

      A 20 MVA transformer can be change to 25 MVA is possible without change in the winding?
      A 20 MVA transformer can be change to 25 MVA is possible without change in the winding?

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    • #1695
      Hamid

        It is possible, as you know the rating capacity of power transformers can be increased by their cooling system modification. Tank-mounted pressed-steel radiators now represent the most widely used arrangement for cooling smaller transformers for which tank surface alone is not adequate. These can now be manufactured so cheaply and fitted so easily that they have totally replaced the arrangement of tubes which were commonly used for most distribution transformers. They are available in various patterns but all consist basically of a number of flat

        #1709
        R K Mohapatra

          If you do not change the windings and want to operate at 25 MVA , (a) The load losses will increase by 56 % (b) The voltage drop will be more on the secondary side . This may ceate problem in ,load sharing if the transformer is operating in parallel with other transformers ( c ) The hot spot temperature of winding will go up if there is no enhanvement in the cooling system. The amount will go up depending upon the type of cooling employed . ( d ) The overlaoding of the transformer can not abide the IEC norms (e ) As a side effect the transformer will be ageing faster than expected .

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