132 kV overhead lines are usually carried on lattice steel pylons, but smaller than used for 275 kV and 400 kV lines.  Sometimes they are carried on wood poles.

The maximum field is produced by the largest design of line – the L7 – when the ground clearance is the minimum allowed – 7.0 m.  The field also depends on the phasing. 132 kV lines usually have Untransposed (U) phasing.

Typical fields are lower than the maximum field because the clearance is usually higher.  The three curves shown here are for the normal U phasing, and three different line designs: L7 (the highest), a smaller pylon design, the L132, and a wood-pole design (the lowest field).

132 kV pylon:	132 kV wood pole:

This table gives some actual field values for the same conditions.

					electric field in V m-1 at distance from centreline
					maximum under line	10 m	25 m	50 m	100 m
132 kV	largest lines	L7 twin bundles 0.305 m lynx	maximum	clearance 7 m phasing U	3615	913	182	81	23
			typical	clearance 10 m phasing U	2372	890	103	72	23
	smaller lines	L132 single conductors 0.4 sq in	maximum	clearance 7 m phasing U	2628	697	154	66	19
			typical	clearance 10 m phasing U	1780	689	86	59	18
	smallest wood-pole design	trident 150 m span single conductors lynx	maximum	clearance 7 m single circuit	1174	588	73	11	2
			typical	clearance 10 m single circuit	583	458	89	15	3

Note:

1. All fields calculated at 1 m above ground level.

2. All electric fields are calculated for the nominal voltage.  In practice, voltages (and hence fields) may rise by a few percent.

3. All electric fields calculated here are unperturbed values.

4. All fields are given to the same resolution for simplicity of presentation (1 V/m) but are not accurate to better than a few percent.

5. Calculations ignore zero-sequence voltages.  This means values at larger distances are probably underestimates, but this is unlikely to amount to more than a few percent and less closer to the line.

6. The “maximum field under the line” is the largest field, which is not necessarily on the route centreline; it is often under one of the conductor bundles.

7. Sometimes, a 132 kV circuit could be carried on a line designed for 275 kV or 400 kV.  Then the electric fields could be larger than shown here.

8. Calculated fields agree well with measured fields.  more