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

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Homework Help Overview

The discussion revolves around a high-voltage transmission line problem involving resistance, current, and power loss. The original poster presents a scenario where a transmission line with a specified resistance carries a current over a certain distance, raising questions about calculating power loss and understanding the relationship between current, voltage, and resistance.

Discussion Character

  • Exploratory, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the conversion of current from amperes to kilowatts and the calculation of total resistance based on the line's length. There are attempts to clarify the relationship between current, voltage, and power loss, with some participants questioning the original poster's calculations and understanding of units.

Discussion Status

The discussion is ongoing, with participants providing insights into the necessary calculations for resistance and power loss. Some guidance has been offered regarding the total resistance and its role in determining power loss, but the original poster expresses continued uncertainty about the next steps in the problem-solving process.

Contextual Notes

There is a focus on ensuring correct unit conversions and understanding the implications of resistance over distance. The original poster is navigating through the problem without clear resolution, indicating potential confusion about the calculations involved.

BunDa4Th
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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 I am 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.
 
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What is the resistance of the power line?

Given that and voltage or current power loss is easy.
 
the resistance of the power line is .30 ohm/km and the current is 1050 A
 
You need the total resistance.
 
.30 ohm/km x 164 km = 49.2 ohm km (total resistance)
 
BunDa4Th said:
.30 ohm/km x 164 km = 49.2 ohm km (total resistance)

Think a bit about the units you have written on the above number.

Now that you have the resistance you should be able to complete the proplem.
 
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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