How the measurement height affects the field produced by an overhead line
The actual field produced by an overhead line depends on several factors. This page illustrates this for one standard line, a 400 kV L12 transmission line with typical loads. Our detailed calculations of fields all specify the conditions they were calculated for.
The higher above ground, the closer to the conductors, and so the higher the field. But usually, over the first couple of metres or so, this is a relatively small effect.
Power-line fields are usually assessed at 1 m above ground. The reason for this is explained here.
See also:
- The fields from the different voltages of power lines
- These pages deal with the size of the field - see also the direction of the field