Calculating Power Loss in a High Voltage Transmission Line

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SUMMARY

The discussion focuses on calculating power loss in a high voltage transmission line, specifically using the formula P = I²R. The parameters provided include a current of 1000 amps, a voltage of 700,000 volts, a distance of 100 miles, and a wire resistance of 0.5 ohms per mile, resulting in a total resistance of 50 ohms. The initial power is calculated as 700 million watts, while the power loss due to resistance is determined to be 50 million watts. The confusion arises from the interpretation of the problem, emphasizing the need to focus on power dissipated rather than the remaining power.

PREREQUISITES
  • Understanding of electrical power formulas, specifically P = I²R
  • Familiarity with high voltage transmission concepts
  • Knowledge of resistance calculations in electrical circuits
  • Basic grasp of power measurement units (watts, megawatts)
NEXT STEPS
  • Research the implications of resistance in high voltage transmission lines
  • Learn about power factor and its impact on transmission efficiency
  • Explore methods for reducing power loss in electrical systems
  • Investigate the role of conductor materials in resistance and power loss
USEFUL FOR

Electrical engineers, power system analysts, and students studying high voltage transmission systems will benefit from this discussion, particularly those focused on optimizing power efficiency and understanding electrical losses in transmission lines.

SparkimusPrime
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A question surprisingly similar to this:

https://www.physicsforums.com/showthread.php?t=17219

I = 1000amp
V = 700,000volt
distance = 100miles
resistance of the wire = .5 ohm / mile

The resistance of my line is 50 ohms, original power is 7e5 * 1e3 = 7e8 watts. Final power, due to P = (I^2) * R, is 1e3^2 * 50 = 5e7 watts

So finding the difference:

7e8 - 5e7 = 6.5e8

The answer given by the teacher is 50 MW (50e6 watts right?). A math error I'm sure, anyone see it?

Peter
 
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I am not sure why you are computing the difference.

The power lost by the line is

P=I2R

End of story, you do not even need to know the total power transmitted.
 
Maybe your teacher wants the power dissipated by the wire, and not the power that is left?

Beat me to it. :smile:
 
Yes sorry, read the problem wrong. Seems to be a common failing with this book, using obscure english to mask the real problem.

Thanks.

Peter
 

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