We need to determine the physical damage in some area of overhead lines that can't be inspected visually. The damage's in general caused by short circuit and air pollution (mostly sulphur compound).

Our idea is to attach strain gauges to the area and measure the change in strain which should be increase as wire's damaged.

Was wondering if I could get some opinions on whether this could potentially work and are there any issues we should considering?

  • 1
    $\begingroup$ Are you only looking at a few areas, many locations, or the entire line? You might want to look at distributed fiber optic strain and temperature sensors which have been developed to assess transmission line damage, among other applications. You can get continuous measurements over many km $\endgroup$
    – haresfur
    Mar 25 '19 at 21:36

It isn't obvious that the strain will change when the wire is damaged.

To take a simple case, consider a wire hanging vertically. The strain depends on the material properties and the weight of the wire. If the dimensions of the wire change globally, the weight and cross section area change in proportion, so the stress and strain remain the same. If there is some local damage to the cable, there will be no significant change in strain except at that local position, and you can't put strain gauges everywhere along the length.

For a horizontal cable hung from poles, the tension will depend on the shape of the cable between the poles, and will change with the thermal expansion of the cable in different weather conditions. That would probably be a bigger effect than what you are trying to measure.

Inspecting the cable "visually" with a camera carried on a drone might be a more practical idea.


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