Method and device for recovering electrical energy from a single-phase or multiphase power cable

A device for recovering energy from a single-phase power cable includes two phase conductors, a magnetic core, in the form of an openable torus, installed around the power cable to form a magnetic circuit able to pick up a magnetic field induced by a primary current passing through the phase conductors, a detection coil wound around the magnetic core, to induce a secondary voltage from the induced magnetic field and deliver across the coil an output voltage usable to power electrical systems, and a heterogeneous magnetic circuit to induce an asymmetrical magnetic flux flow in the magnetic circuit and maximize the output voltage of the detection coil.