LV pulse echometry methods
Power cables: pre-locating faults using echometry

This method can also be called BT echometry in comparison, as this perfectly characterizes the way it is to be used.

With the echometer aimed at the 3 phases of the faulty cable, an internal switch directs the pulse successively to each phase. Depending on the device, the echograms of 2 or 3 phases can be displayed one on top of the other.

At a minimum, the echometer displays the phases in pairs, in rotation: L1/L2, L2/L3, L3/L1.

This method requires a "healthy" phase, from an echometric point of view: this translates into the need to have a measured resistance greater than around 150 Ω on a network without shunts, and greater than around 50 Ω on a network with shunts.

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