Abstract: A medium-voltage substation includes at least two insulative material chambers each provided with at least one opening for the gas-tight passage of a set of three-phase busbars. Each chamber contains a three-position three-phase switch for connecting the busbars to first gas-tight electrical feed-throughs and for connecting the first feed-throughs to second gas-tight feed-throughs connected to ground. The first feed-throughs of at least one chamber are each electrically connected to a single-phase cable. The first feed-throughs of each chamber are electrically connected either to a fuse or to a pole of a circuit-breaker disposed in an insulative material compartment.

Abstract: A medium-voltage or high-voltage circuit-breaker including, in a casing filled with a dielectric gas, an interrupting chamber in which metal plates are disposed for splitting up an electric arc into a multitude of smaller or "elementary" arcs under the action of a magnetic field, the circuit-breaker including a helical insulating ramp winding around a central generator line, the ramp being disposed on the inside peripheral portion of the chamber and around a conductive electrode, and the metal plates being disposed along the ramp, around and at a distance from the conductive electrode.

Abstract: The present invention consists in a connection arrangement between at least one pair of conductors that pass through respective walls (6). Each wall (6) is made of insulating material and the two walls are connected together via a peripheral sealing gasket received in a groove (7') and delimiting an empty space between the walls which is filled with dry air. The connection made in this way is small in size and is particularly easy to implement.

Abstract: A high tension or medium tension circuit breaker having abutting arcing contacts. The circuit breaker includes a gastight insulating case filled with a gas having good dielectric properties. The case contains a stationary arcing contact; a moving arcing contact driven by a drive rod actuated by a mechanism outside the case. A blast chamber is defined by a piston integral with the moving arcing contact, slidably received in a fixed cylinder terminating in a blast nozzle, the cylinder and a ring. The circuit breaker further includes a lost motion mechanism to enable the drive rod to move over a given length in the circuit breaker opening direction without driving the moving arcing contact away from the fixed arcing contact.

Abstract: A medium or high tension circuit breaker comprising a shell filled with a dielectric gas under pressure and containing: a fixed main contact, a moving main contact, a fixed arcing contact, and a moving arcing contact between which an arc is established during contact separation. The arc within the circuit breaker is split up into a large number of elementary arcs, with each elementary arc being established between two metal plates.