Power factor

Discussion in 'General Electronics Chat' started by tadm123, Jun 9, 2014.

  1. tadm123

    Thread Starter Member

    Nov 20, 2013
    43
    0
    Sorry for the short title but it was the only way to get past the bug.

    I have a couple of question about P.F and Electrical companies.

    First one is why does the power companies want the power factor in your home ideally to be 1? And second, why do they want to eliminate reactive power if it's just a transfer of energy back and forth, what do they lose?

    Thanks in advance.
     
  2. inwo

    Well-Known Member

    Nov 7, 2013
    2,433
    315
    It's not a loss-less transfer.
    The current thru the line resistance, I squared R, represent real power loss.
     
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  3. Lestraveled

    Well-Known Member

    May 19, 2014
    1,957
    1,215
    AC loads that are not purely resistive (reactive or non-linear current) put stresses on the power system that it would normally not have if the loads were resistive. With reactive AC loads the current waveform is not in phase with the voltage waveform. Too many reactive loads in a system can effect the voltage waveform, distorting the normal sine wave. Also, the apparent current is greater than the real current, which is where the extra stress comes in.
    Another bad PF load is the rectified AC power supply. Their current waveform looks more like pulses instead of the desired sine wave waveform. These current pulses are much higher than the equivalent sine wave of equal density. More stress and lots of noise.

    Mark
     
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  4. tadm123

    Thread Starter Member

    Nov 20, 2013
    43
    0
    I see, thanks guys.
     
  5. daviddeakin

    Active Member

    Aug 6, 2009
    207
    27
    Because their cables and transformers have to be made bigger, since they have to handle the full reactive current, not just the real current that does useful work.
     
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