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.

Abstract: A device for controlling a circuit-breaker intended for opening and closing this electric power cut-off device comprising a mobile contact, this control device comprising a motor with a rotary output shaft and being connected to power supply means and actuating means transforming the output displacement of the motor into a displacement of the contact, this device also comprising a mechanical spring arrangement involved in opening and closing the contact. The actuation means include a set of jointed elements providing the connection of the rotary shaft and of the ring, and, in the closed position of the contact, the set of jointed elements is near a dead centre position, a so-called open dead centre, the opening spring being only able to drive it towards the open position upon moving past this dead centre during opening.

Abstract: The invention relates to a device for controlling a circuit-breaker intended for opening and closing this electric power cut-off device comprising a mobile contact, this control device comprising a motor (3) with a rotary output shaft (12) and being connected to power supply means (4-9) and actuating means transforming the output displacement of the motor into a displacement of the contact, this device also comprising a mechanical spring arrangement involved in opening and closing the contact. According to the invention, the actuation means include a set of jointed elements providing the connection of the rotary shaft and of the ring, and, in the closed position of the contact, the set of jointed elements is near a dead centre position, a so-called open dead centre, the opening spring (15) being only able to drive it towards the open position upon moving past this dead centre during opening.