# Electric Field Generated by Transmission lines

1. Mar 1, 2012

### I_am_learning

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.

2. Mar 2, 2012

### I_am_learning

I am sort of bumping this thread. Does anybody, at least knows some place for studying about electric fields generated by transmission lines?

3. Mar 3, 2012

### yungman

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.

4. Mar 3, 2012

### jim hardy

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?

5. Mar 5, 2012

### I_am_learning

I got the program sorted out.
Thanks anyways for help.