Abstract: A detection device for detecting a short circuit current in an electrical power transmission cable having an electrical power transmission cable for a high-voltage DC network. The network includes a central core, an insulating sheath, a metal screen arranged around the insulating sheath, at least one optical fibre, arranged between the electrically conductive central core and the metal screen by forming windings around the central core in a detection region, two optical transmitters arranged at the ends of the electrical power transmission cable, two optical detectors arranged at ends of the electrical power transmission cable, two interruption devices arranged at the ends of the electrical power transmission cable when a change in the angle of polarisation with respect to a reference angle greater than a predetermined value is detected by the first optical detector.