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Why Power factor changes from primary to secondary side of the described transformer

  1. Jul 20, 2012 #1
    I have a query about the power factor change in a power plant. There are 8 gas engines in parallel. When 1 engine runs with a set p.f of .8 the output at the delivery after transformer (11/132kv, step up Ynd1) is almost same. But when all generators are running with each having .80 p.f the p.f after transformer changes to .85. (All gensets are in parallel equal capacity and connected to single transformer and distance from gen to trans is comparatively small). Is this only for the transformer reactive loss or other thing is associated with this. Why the p.f increases and any calculation regarding the consumed VAr of the x-former. please specify elaborately.
    If you need any further information please specify. I am the engineer of that power plant so can give you enough detail information.
  2. jcsd
  3. Jul 20, 2012 #2

    jim hardy

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    Re: Why Power factor changes from primary to secondary side of the described transfor

    what are you using to determine PF? Wattmeters, varmeters, ammeters, Qmeters ?

    What is impedance of your transformer?

    What would be per unit drop across transformer with one generator, and with 5 ?

    old jim
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