Device for detecting a short circuit current in an electrical power transmission cable comprising: - An electrical power transmission cable for high voltage direct current network comprising: • an electrically conducting central core configured for transmitting an electrical current, • an insulating envelope electrically disposed around a central core, • a metallic screen disposed around the insulating envelope, - wherein the electrical power transmission cable also contains at least one optical fibre extending along the electrical power transmission cable in which, in at least one detection zone of the electrical power transmission cable, the said at least one optical fibre is disposed between - the electrically conducting central core and the metallic screen forming windings (E1 > E2> E3) around the central core, - a first optical emitter disposed at the first end of the electrical power transmission cable and configured to transmit an optical signal in a first optical fibre of the said electrical power transmission cable, - a second optical emitter disposed at the second end of the electrical power transmission cable and configured to transmit an optical signal in the first optical fibre or another optical fibre of the said electrical power transmission cable, - a first optical detector disposed at the first end of the electrical power transmission cable and configured to detect a change in the polarisation angle of the optical signal transmitted by the second optical emitter and associated with a fault signal, - a first interrupting device disposed at the first end of the electrical power transmission cable, coupled with the first optical detector and configured to interrupt the connection of the electrical power transmission cable when a change in the polarisation angle with respect to a reference angle greater than a pre-determined value is detected by the first optical detector, - a second optical detector disposed at the second end (1 B) of the electrical energy transmission cable and configured to detect a change in the polarisation angle of the optical signal transmitted by the first optical emitter and associated with a fault signal, - a second interrupting device (21 B) disposed at the second end (1 B) of the electrical power transmission cable, coupled with the second optical detector and configured to interrupt the connection of the electrical power transmission cable when a change in the polarisation angle with respect to a reference angle greater than a pre-determined value is detected by the second optical detector. - An electrical power transmission cable for high voltage direct current network comprising: • an electrically conducting central core configured for transmitting an electrical current, • an insulating envelope electrically disposed around a central core, • a metallic screen disposed around the insulating envelope, • an electrically conducting central core configured for transmitting an electrical current, • an insulating envelope electrically disposed around a central core, • a metallic screen disposed around the insulating envelope, - wherein the electrical power transmission cable also contains at least one optical fibre extending along the electrical power transmission cable in which, in at least one detection zone of the electrical power transmission cable, the said at least one optical fibre is disposed between - the electrically conducting central core and the metallic screen forming windings (E1 > E2> E3) around the central core, - a first optical emitter disposed at the first end of the electrical power transmission cable and configured to transmit an optical signal in a first optical fibre of the said electrical power transmission cable, - a second optical emitter disposed at the second end of the electrical power transmission cable and configured to transmit an optical signal in the first optical fibre or another optical fibre of the said electrical power transmission cable, - a first optical detector disposed at the first end of the electrical power transmission cable and configured to detect a change in the polarisation angle of the optical signal transmitted by the second optical emitter and associated with a fault signal, - a first interrupting device disposed at the first end of the electrical power transmission cable, coupled with the first optical detector and configured to interrupt the connection of the electrical power transmission cable when a change in the polarisation angle with respect to a reference angle greater than a pre-determined value is detected by the first optical detector, - a second optical detector disposed at the second end (1 B) of the electrical energy transmission cable and configured to detect a change in the polarisation angle of the optical signal transmitted by the first optical emitter and associated with a fault signal, - a second interrupting device (21 B) disposed at the second end (1 B) of the electrical power transmission cable, coupled with the second optical detector and configured to interrupt the connection of the electrical power transmission cable when a change in the polarisation angle with respect to a reference angle greater than a pre-determined value is detected by the second optical detector.