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Negative reactive power

  1. Dec 16, 2013 #1
    In a three phase power system,delta connected 66kV transmission line,the reactive power in one of the line/phase is negative(capacitive) while the reactive power in the other two lines/phases is positive.What is causing the reactive power to be negative(capacitive) in this phase?What are some possible solutions towards mitigating this negative(capacitive) reactive power?
  2. jcsd
  3. Dec 16, 2013 #2


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    Welcome to Physics Forums.

    Adding capacitors will decrease the Vars, adding inductors will increase the Vars, or you can use the what's called a Synchronous Condenser which will either increase or decrease Vars.

  4. Dec 17, 2013 #3
    This could be caused by many things - How much are you talking about? How many VAR relative to Watts, if it is a small amount(near unity - or very low real power flowing) this could be a "normal" system condition, one line is actually more capacitive than the other lines. However is it is a significant amount of VARs at significant power - I would check that the CTs/PTs , instruments are connected properly. Is the POWER in that leg reversed as well?
    What device is being used to tell you that the PF is +/-? Is there any way to get a complete vector diagram of the readings.
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