Electric Field Generated by Transmission lines

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Discussion Overview

The discussion revolves around the calculation of the electric field generated by transmission lines, particularly focusing on the effects of three-phase power lines and the complexities introduced by their configuration and changing voltages.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant suggests that the time average electric field near transmission lines should be zero due to the alternating voltages, based on symmetry principles.
  • Another participant questions the initial claim and asks for more details about the type of transmission line and the formulas used in the software.
  • A different participant proposes treating the three lines as individual line sources and summing their fields, noting that the significant field occurs only when distances to the lines differ significantly.
  • This participant describes the voltages of the three lines as sinusoidal functions with phase shifts, indicating that the resultant electric field depends on the relative distances from each line.

Areas of Agreement / Disagreement

Participants express differing views on the behavior of the electric field near transmission lines, with no consensus reached on the initial assumptions or the implications of the three-phase configuration.

Contextual Notes

The discussion highlights potential limitations in understanding the electric field due to assumptions about symmetry and the complexity introduced by the three-phase system. There are unresolved mathematical steps regarding the calculation of the fields from multiple sources.

Who May Find This Useful

Individuals interested in electric fields, transmission line theory, and those developing software for electromagnetic field calculations may find this discussion relevant.

I_am_learning
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I am trying to make a software to calculate electric field near transmission lines. When I checked it I got one awkward looking result.

At any point near the Transmission line, I guess the time average (or net) Electric Field should be 0. Why should it have any preference on a value and hence on a direction because the Voltages are constantly changing from +ve and -ve. I guess we can tell this from basic principle of symmetry.
But presence of 3 lines and their images (below the ground), makes all these confusion to me.
Since my software returned result counter to my intuition, I am seeking some help here.
Thanks.
 
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I am sort of bumping this thread. Does anybody, at least knows some place for studying about electric fields generated by transmission lines?
 
Can you describe it in more detail? What kind of transmission line you are using? Show me some formulas that you use for the program. I really don't quite follow what you said.
 
But presence of 3 lines and their images (below the ground),

3 phase power lines?

Probably tis is oversimplification.
But for starters,
Try considering them as individual line sources and sum the fields

Since the three voltages add to zero, there'll only be a significant field when you're close enough to them that individual distances to the three differ significantly.

One wire has voltage Vsin(wt)
next has Vsin(wt+120°)
last has Vsin(wt-120°)

so, there'll be a field from each line inversely proportional to distance from that line.
The more nearly equal the three distances, the more nearly the three fields add to zero.

Is this what your software showed?
 
I got the program sorted out.
Thanks anyways for help.
 

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