Abstract: The invention concerns an electric power substation for use at very high voltages.The substation comprises a circuit-breaker (4) connected to a busbar (29) by a vertical isolating switch (15), the projection (31) on the floor plane (1) of the live components (19) of the isolating switch not intersecting that (34) of the circuit-breaker and lying wholly within a circle whose diameter is less than thirty percent of the opening distance (32) of the isolating switch, said components being for the most part located above the circuit-breaker.Application to substations for use at voltages of 245 kilovolts and above.

Abstract: The invention relates to a resistance switch-in device for switching in only when a circuit breaker closes, said switch-in device including a moving arcing contact in an interrupter chamber. The device is characterized in that the switch-in contacts (2 and 3, 32 and 33) are disposed in the interrupter chamber (1) of the circuit breaker and that since at least one (2,32,33) of said switch-in contacts is a moving contact, it moves on a path parallel to that of the moving arcing contact (5). The invention applies in particular to connecting a load to long-distance high-tension circuits that are unloaded.

Abstract: The invention relates to a set of metal-clad bars for a high-tension unit. A metal casing contains an insulating gas and is formed by cylindrical lengths whose ends have flanges to connect them to the adjacent lengths. The set of bars is characterized in that said lengths are disposed in a longitudinal alignment, and at least one of the connection flanges of a length (12) is disposed in a plane which is inclined with respect to the longitudinal axis of the casing (1) and concurrent with the plane of the flange (22) situated at the other end of said length.

Abstract: The invention relates to a safety device for protection against the rise of pressure in a pneumo-hydraulic control circuit which includes, upstream, a pressure generator and downstream, a pneumo-hydraulic accumulator. The device is characterized in that it includes, between the generator (3) and the accumulator (1) a non-return valve (6), a first safety valve (4) capable of a discharge at least equal to that of the generator upstream from the non-return valve, a second safety valve (5) downstream from the non-return valve and means for the second safety valve to be subjected to only a small discharge. The invention applies in particular to the pneumo-hydraulic control of very high tension cut-out switches.

Abstract: A gas-blast circuit-breaker which includes at least one cutout chamber including at least one blast valve with two seats, one of which, when the valve is opened, is situated on the blast-gas exit path. The breaker is characterized in that a moving slide valve is associated with the valve, in such a manner that opening the valve causes a slightly delayed movement of the slide valve in the same direction as the valve and along the same axis, so that it masks said valve seat situated on the exit path of the hot blast-gases arriving from extinguishing the arc when the blast-gases flow towards the outside; the slide valve being opened by compressed gas contained in the gas-blast circuit-breaker.

Abstract: An articulated contact finger of very high voltage gasblast circuit-breaker. It is characterized in that the pin on which the finger is articulated is disposed between the contact piece and a spring which provides the force required at the contact point, a first support of the stationary articulation pin being situated between the articulation pin and the spring, said spring being disposed between said first support and a second support providing fixing means for the flexible connection connected to the contact point.