ELECTRIC CABLE WITH STRAIN SENSOR AND MONITORING SYSTEM AND METHOD FOR DETECTING STRAIN IN AT LEAST ONE ELECTRIC CABLE

An electric cable comprising a strain sensor longitudinally extending along the cable and including a strain optical fibre arranged within a bending neutral region surrounding and including a bending neutral longitudinal axis of the electric cable, and at least two longitudinal structural elements, at least one of the at least two longitudinal structural elements being a core comprising an electrical conductor, wherein the strain sensor is embedded in a strain-transferring filler mechanically coupling at least one of the at least two longitudinal structural elements with the strain sensor. With the disclosed cable construction, the strain experienced by the at least one of the at least two longitudinal structural elements is transferred to the strain sensor at least in a strained condition. In the preferred embodiments, the electric cable is a heavy-duty cable. The invention relates also to a method for monitoring the strain, and preferably also the temperature, of an electric cable. Further, the invention is directed to a deformation monitoring system for measuring at least the tensile strain of a plurality of electric cables, and in particular of a plurality of heavy-duty cables.