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Why does AC have less copper loss than DC

  1. Jun 26, 2016 #1
    Hi there everyone, I'm doing some study on electronics and the section on the advantages of A/C over DC mentioned that AC has less copper loss (I^2 x R), But to me this seems contradictory to the skin effect. Could someone please tell me why AC has less copper loss.
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  3. Jun 26, 2016 #2


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    For the same voltage and for the same power transmitted over a copper line, DC has less power loss. https://en.wikipedia.org/wiki/High-voltage_direct_current

    However the reason that AC power transmission has dominated is that the equipment to transform between high voltage (in order to transmit the power for fewer losses) and low voltage (power for domestic use) is cheaper and less complicated. AC generators were also cheaper and more efficient.
  4. Jun 26, 2016 #3


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    I suspect this is confused. Most likely it's due to the answer that Delta gave eg...

    AC power transmission is done at higher voltage. Higher voltage implies lower current for same power. Lower current means lower I2R losses in the copper wire.
  5. Jun 26, 2016 #4


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    This is probably in reference to the development of the area-wide power distribution system, in an era when the choice was basically between DC all-the-way or AC all-the-way. Transformers enabled the efficient transmission of AC at high tension followed by a step-down to consumer voltages, whereas there was no equivalent available for efficiently stepping down DC at the power levels involved.

    Transmitting low tension DC throughout a power network involves cripplingly-high I2⋅R losses.
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