How to measure the dimensions of the power line

Checking the dimensions at the intersection of the power line with engineering structures is carried out after reconstruction or repair of the line with a change or rearrangement of wires, construction of any structures under the line.

Line size (wire gauge above ground) is the allowable vertical distance from the bottom of the lower conductor to the ground.

The size of crossings is the smallest distance from the conductors of the line vertically to the surface of highways and railways, rivers, conductors of communication lines when they are crossed by an overhead line. The dimensions of overhead power lines are determined by PUE.

Instant measurement of the dimensions of the power line loaded with insulating rod refers to the simplest and most accurate way to measure dimensions. In this case, the distance between the conductors of two intersecting lines is determined by the difference in the dimensions of the intersecting and intersected lines.

Rice. 1. Location of the conductor in the section: zo is the distance from the lowest point of the conductor to the ground, m.

If you measure with a stick the size of the line and the distance from the point of attachment of the wire to the insulator to the ground, then the difference between the last value and the size of the line will allow you to set the wire sag.

Line size can also be measured using marked cotton or nylon ropes whose ends are jointed with the reel. The roll is superimposed on the wire with the help of an insulating rod. By moving the roller along the wire, measure the length of the rope from a given point on the wire to the ground.

Rice. 2. Theodolite

The size of the line is also determined using various optical devices (theodolite, altimeter, the simplest optical devices).

To measure the dimensions, the theodolite or the simplest optical device is installed at a certain distance x (usually 10 — 20 m) from the projection of the wire on the earth's surface, and the angle φ is measured between the tube of the optical device and the wire (or directly tgφ). The size is then determined as follows: 30 = a + xtgφ, where a is the height of the optical device tube above ground level.