Abstract: A gas-insulated cable having a plurality of lengths connected end to end, each length containing three conductors with the ends of the conductors of a length having respective metal endpieces engaging in respective cylindrical terminal metal portions of the corresponding conductors of the adjacent length, the terminal portions being provided with respective internal contacts co-operating with the endpieces, wherein a respective insulating sleeve of length substantially equal to twice its diameter is disposed around each of the endpieces and between the endpiece and the inside wall of the terminal portion.

Abstract: A compressed gas interrupter comprises two contact assemblies each including at least one wear contact and one of which is mobile along an axis relative to the other, which is fixed. The mobile contact assembly is moved along the axis by an insulative maneuvering rod and has a gas compression chamber which, in the open position, communicates via an insulative nozzle with an expansion chamber. The compression chamber includes a piston attached to the hollow wear contact of the mobile contact assembly and which slides in a cylinder attached to the maneuvering rod, the cylinder delimiting the compression chamber with the piston and the nozzle. The hollow wear contact is mobile relative to the maneuvering rod. A system using balls immobilizes the hollow wear contact during initial travel of the maneuvering rod to open the interrupter and constrains the hollow wear contact to move with the maneuvering rod at the end of its travel.

Abstract: An electric switch for use in a five-pole isolating switch used as a phase inverter has a fixed contact and a mobile contact cooperating with the fixed contact to open or close an electrical line. The mobile contact is moved in a longitudinal direction by an articulated pair of levers. An isolating switch used as a phase inverter having five switches comprises a single three-position actuator for maneuvering the mobile contacts through a linkage.

Abstract: A gas-insulated cable includes a plurality of sections separated by sealed partitions, each section including a cylindrical steel case, a cylindrical aluminum screen coaxial with and inside the case and three conductors. A monitoring device includes, between the case and the screen, optical fibers equal in number to the number of sections of the cable and extending from one end to the other of the cable, each of the sections being monitored by a single fiber. The monitoring device further includes at least one optical internal arc detector inserted in series into each fiber in the corresponding monitored section, at each end of the device, a device for detecting light conveyed by the optical fibers, and at least one optical threshold temperature detector inserted in series into each fiber in the corresponding monitored section.

Abstract: The present invention relates to a method of manufacturing an insulator made of a composite material and including a cylindrical casing provided with annular fins. The method includes the steps of manufacturing an epoxy resin cylinder provided with epoxy resin annular fins covering the resulting cylinder with a covering of a material that withstands the electrical potential gradient under atmospheric conditions.

Abstract: A method of discriminating an arc detected in metal-clad equipment includes detecting an arc, generating an arc-appearance signal, transmitting the arc-appearance signal to a computer, and determining a time lapse T. The time lapse T is determined according to the formula t.sub.o -t.sub.a ; t.sub.o is an instant at which the computer receives a circuit breaker trigger order, and t.sub.a is an instant at which the arc-appearance signal is first acquired by the computer. The arc is determined to be an internal arc (1) if the time lapse T is positive, or (2) if the time lapse T is negative and its absolute value is less than or equal to 10 ms. On the other hand, if the time lapse T is negative and its absolute value is greater than 10 ms, variation of the arc-appearance signal is analyzed to discriminate the arc.

Abstract: A protection system for a three-phase distribution transformer immersed in a liquid dielectric contained in a tank, at least two of the three phases being equipped on the high voltage side of the transformer with respective current-limiting fuses. On each of the two phases equipped with current-limiting fuses, a protective micro-fuse is also connected in series with the current-limiting fuses and which operates faster than the current-limiting fuse. In addition, each micro-fuse is associated with a striker which, in turn, is connected to a mechanical trigger system which causes a three-phase short-circuiting device connected across the three phases to close in the event of a micro-fuse operating. Furthermore, the system includes at least one fault detector detecting one of pressure in the tank or the level of the dielectric. In particular, the three-phase short-circuiting device is situated on the high voltage side of the transformer between the current-limiting fuses and the high voltage windings.

Abstract: A circuit-breaker including main contacts and arcing contacts includes a shaft carrying a first lever connected to the moving main contact. A hub is mounted inside the shaft and carries a second lever connected to the moving arcing contact; the shaft and the hub being shaped over a certain portion into two sectors between which a spring is disposed. A single control causes the shaft to rotate so that the shaft firstly causes the hub to rotate via the spring, the shaft and the hub rotating respectively causing the moving main contact and the moving arcing contact to move, and the shaft secondly rotates to a further extent, with the hub being prevented from rotating by action from an abutment. This arrangement makes it possible to implement a simple synchronization of the main contacts opening before the arcing contacts.

Abstract: The method consists in: i) making a series of recordings of the density of the gas at regular time intervals during a nighttime period by means of a temperature-compensated pressure sensor fixed on the outside of the envelope and communicating with the gas via a duct formed through the thickness of the envelope; ii) processing the density recordings of the gas acquired during the nighttime period in hourly intervals, each hourly interval giving rise to an hourly mean value for the density of the gas; iii) processing the hourly mean values obtained at the end of each hourly interval to give a daily mean value for the density of the gas at the end of the nighttime period; and iv) determining the leakage rate from the envelope by taking the difference between mean densities obtained at the ends of two different nighttime periods.

Abstract: A high-tension circuit-breaker includes fixed contacts and a mobile assembly including mobile contacts. The mobile assembly is connected to an operating mechanism by an operating rod. The circuit-breaker includes a device for damping movement of the rod at the end of a tripping maneuver. This device includes a damper piston entrained by movement of the rod at the end of the tripping maneuver and moving in a cylinder in one direction such that the volume between the piston and an end wall of the cylinder increases during the maneuver, causing a pressure drop in this volume.

Abstract: A puffer type circuit breaker comprising a compression chamber closed by a pressure wall of a semi-moving piston, a first mechanism for preventing the piston from moving during a first portion of the opening displacement of the moving contact assembly, and a second mechanism for axially displacing the piston together with the moving contact assembly during the second portion of the same displacement. The piston includes a cylindrical guide portion secured to the wall. The first mechanism comprises an abutment member disposed between the end of the guide portion of the piston and a fixed retaining part, said abutment member being retractable. The second mechanism comprises an arrangement for retracting the abutment member, and acting at the end of the first displacement portion.

Abstract: A control device for high-voltage equipment includes a computer adapted to receive status information from the equipment via at least one transmission cable. A display system includes a support device carrying on its visible face an equipment status mimic diagram associated with indicator lamps and at least one connector connected directly to the transmission cable, incorporating the indicator lamps and removably connected to the computer at a connection face thereof. The support device and the connector are so disposed that the latter presents the indicator lamps in a manner associated with the mimic diagram of the support device whether it is connected to the computer in a normal position or disconnected from the computer in an emergency position.

Abstract: A high voltage circuit breaker with insertion of resistance on closing, wherein the resistance is inserted by a fixed insertion electrode co-operating with the end of the moving main contact, the blast nozzle and the arcing contact of the moving assembly being secured to each other, and the subassembly being movable relative to the moving assembly so that on triggering, because of the inertia of said subassembly, the arcing contacts separate after the insertion electrode and the end of the moving main contact have moved sufficiently far apart.

Abstract: A system for actuating electrical equipment, in particular a high-voltage section switch or a high-voltage grounding section switch includes, in a control box, a rotary drive unit for driving the contacts of the equipment. A control circuit includes "end-of-stroke" contacts associated with the contacts of the equipment. The system includes a portable electric motor having a self-contained power supply. The motor is equipped with a mechanical coupling for mechanically coupling the motor to the rotary drive unit, and is provided with an electrical connector for connecting the motor to the control circuit.

Abstract: The invention relates to a method of protecting against circuit breaker failure, said circuit breaker having contacts capable of moving between a closed position and an open position, and vice versa, and being fitted with protection apparatus including fault detector apparatus for putting into operation an opening electromagnetic coil that actuates circuit breaker contact drive apparatus, with position-indicator contacts of monitor apparatus being changed over as soon as the circuit breaker contacts start to move. According to the invention, in the event of a fault being detected, a time delay is generated from the indicator contacts changing over, and at the end of said time delay it is verified whether the fault current has become zero, and if not an alarm is generated.

Abstract: A gas-blast gas-insulated high-voltage circuit-breaker comprises a fixed main contact, a fixed arc contact and a mobile assembly comprising a main contact, an arc contact and a compression volume cooperating with a fixed piston and communicating with a blast volume leading to a blast nozzle. The compression volume is provided with a valve preventing the gas passing from the blast volume to the compression volume. The piston comprises openings for evacuating the gas from the compression volume during tripping, these openings being closed between the start of compression of the compression volume and the closure of the valve and open upon closure of the valve.

Abstract: This present invention concerns a circuit-breaker of the self-blasting type including a system for immobilizing the semi-mobile piston during a first part of displacement of the mobile contact assembly between the closed position and the open position and for displacing the piston axially during a second portion of the same displacement of the mobile contact assembly. This system includes at least one first longitudinal slot and at least one second longitudinal slot on the fixed tube, a freely rotatable locking tube carried by the fixed tube, aligned with the slots thereof and including at least one first longitudinal slot and at least one second longitudinal slot, at least one pin carried by the second tube and penetrating the first slot of the fixed tube and the first slot of the locking tube, and at least one pin carried by the piston and penetrating the second slot of the fixed tube and the second slot of the locking tube.

Abstract: A conductor bar for a metal-clad high voltage electrical apparatus, the bar including a metal tubular cylinder of diameter (D) provided at at least one of its ends with a connection flange for connection to an insulator. Between an end and the flange, the bar presents a cylindrical portion of diameter (d) less than (D) and connected to the cylinder via a transition portion formed by a conical annulus. The transition portion is provided with at least one slot forming a current path that extends transversely relative to the bar.

Abstract: A buried armored power transmission line includes a metal jacket housing at least one conductive busbar. The line is equipped with a cooling device operating by transferring heat from the jacket to the surface of the soil, including a metallic structure fixed to the jacket and extending towards the surface of the soil. This structure has a plurality of vertical first plates connected to the jacket having a vertical dimension such that their top edge is at a permissible calculated depth.

Abstract: A circuit-breaker including a moving assembly having a moving main contact (14) electrically connected to a first terminal (2A), a fixed assembly having a fixed arcing contact electrically connected to a resistance (5) which is connected to a second terminal (3A), and a temporary insertion assembly for temporarily inserting the resistance when closing the circuit-breaker. The fixed arcing contact is an elongated metal rod (11) having a first end (11A). The temporary insertion assembly includes a ring (22) that slides along and electrically contacts the metal rod. The ring has first contacts (25) that cooperate with the moving main contact (14), and second contacts (31) that cooperate with third contacts (32) connected electrically to the second terminal (3A). A first biasing member (29) biases a cylindrical insulating pusher (28) toward the moving assembly, and a second biasing member (40) biases the insertion assembly in the same direction.