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B Confusion with regards to power lines and the power lost

  1. Mar 11, 2017 #1
    Ok, so the title was pretty vague, I'm not sure how to succinctly describe the confusion. Anyway, so I've learnt that the power lost is P=I2R, and so by increasing the voltage, as P=VI and is constant, the current will be lowered, and thus the power lost will decrease.
    I'm confused about a couple things. While my physics teacher was specifically talking about P=I2R, should not P=V2/R also give the value, and so by increasing the voltage we increase the power lost? Is this not a contradiction?
    I feel like it could be remedied if the wires in power lines are not ohmic conductors and so half the math I did above is invalid.
    Anyway, any help would be greatly appreciated, thank you!
  2. jcsd
  3. Mar 11, 2017 #2
    The calculation relates to the power dissipated (lost) in the transmission cables so the voltage you need is the voltage across the cables. I think you are confusing this with the voltage across the load (at the end of the cables)
  4. Mar 11, 2017 #3
    Can you explain this a little more in depth? My teacher explained this very superficially so I'm not too sure on this.
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