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What is the power loss due to resistance in the line?

  • Thread starter BunDa4Th
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  • #1
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Homework Statement



A high-voltage transmission line with a resistance of 0.30ohm/km carries a current of 1050 A. The line is at a potential of 670 kV at the power station and carries the current to a city located 164 km from the station.

(a) What is the power loss due to resistance in the line? W

(b) What fraction of the transmitted power does this loss represent? %

Homework Equations



W = AdeltaV


The Attempt at a Solution



first i did 1050A/1000 to convert that into 1.05 kA (not sure if this is correct)

then i did 1.05 x 670 = 703.5 kW or 703500 W (still not sure if im doing this correctly)

that is when i get lost on how to do the next step, but from what i been doing i think i am doing it wrong and it will only lead me to confuse myself even more.

thanks for any help.
 

Answers and Replies

  • #2
Integral
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What is the resistance of the power line?

Given that and voltage or current power loss is easy.
 
  • #3
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the resistance of the power line is .30 ohm/km and the current is 1050 A
 
  • #4
Integral
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You need the total resistance.
 
  • #5
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.30 ohm/km x 164 km = 49.2 ohm km (total resistance)
 
  • #6
Integral
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.30 ohm/km x 164 km = 49.2 ohm km (total resistance)
Think a bit about the units you have writen on the above number.

Now that you have the resistance you should be able to complete the proplem.
 
  • #7
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Okay, i been trying to figure this out and still lost on how I would go about finding the power loss due to the resistance.

I know that to get the total power its A x DeltaV = total W

so i did 1050A x 670000 = 703500000 W (which might be wrong) since i think 670 kV = 670000

that is where i am unsure what to do next or what I need to do with the total resistance
 

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