Abstract: A high or medium voltage electrical switch, particularly a GIS type isolating switch with three switching positions and a grounding position, includes a switching element in a closed and sealed enclosure that can be filled with a dielectrically insulating gas, containing a mobile switching element free to move along an axial direction to electrically connect two conducting bars at intervals from each other, and also including a fixed ground contact to be electrically connected to one of the two conducting bars through the switching element when the switch is in the grounding position. The fixed ground contact is offset from the path of the switching element along the axial direction and the switching element forms a Y with a contact pin such that the contact pin and the fixed ground contact engage in each other through displacement of the switching element along the axial direction.

Abstract: The gas exhaust comprises a generally cylindrical shaped casing (26) closed by a bottom (18, 22) at one end and with openings (30) to allow gas to escape. A duct (16) is arranged in the casing (26) to delimit a central passage inside the duct, and an annular passage (42) surrounding the central passage (40) outside the duct between it and the casing (26). There is a communication consisting of four holes (20) in the duct (16) close to the bottom (18) to form a communication between the central passage (40) inside the duct (16) and the annular passage (42). The casing (26) includes two diametrically opposite openings (30) located in a horizontal plane.

Abstract: The invention relates to a device (10) for operating in a water chamber (7) of a heat exchanger (1) comprising a wall (6) of substantially hemispherical shape and, at its upper portion, a tube plate (5) traversed by a plurality of vertical holes (4). The device comprises at least one rail (11) furnished with members for attachment on the bottom face of the tube plate (5) and supporting at least one trolley (15) that can be moved along the said rail (11) and fitted with a pendular lifting means (19) and a robotic arm (20) comprising an attachment base (30) furnished with members for coupling on the bottom face of the tube plate (5) and a drive means interacting with the lifting means (19) to draw the attachment base (30) against the tube plate (5). The invention applies more particularly to the steam generator of a pressurized water nuclear reactor.

Abstract: The high-voltage metal-clad substation element comprises at least one circuit-breaker connected electrically and mechanically to at least one set of busbars (3, 4) extending along an axis (D) that extends transversely to the longitudinal axis (AX) of the circuit-breaker. The metal case (1) is fixed to the ground via a hinge which allows the case to tilt slightly when said set of busbars (3, 4) expands along said transverse axis (D). This configuration makes it possible to omit or to reduce the use of axial bellows on the set of busbars, thereby reducing the cost of manufacturing the metal-clad substation. Advantageously, in association with the hinge, the metal case is designed to have some flexibility to reduce mechanical stresses when the set of busbars expands.

Abstract: The invention relates to a control device for controlling electrical switchgear, the control device including an actuating arm (8) having a connection point (8b) suitable for being moved along a closed line (L) including points P1, P2, and P3: during an opening stage for opening the moving contact, under the effect of a mechanical spring (12), from point P1 to point P2; during a re-cocking stage for re-cocking the mechanical spring (12), under the effect of a motor (10) being switched on, and while keeping the moving contact in the open position, from point P2 to point P3; and during a closure stage for closing the moving contact, also under the effect of the motor being switched on, from point P3 to P1.

Abstract: Process for the preparation of a semiconducting ceramic based on doped tin oxide SnO2 by a process of “PADO” (Precursor Alloy Direct Oxidation) type applied to an alloy of tin and of doping metals or by a process of “PADO” type applied to tin, the doping metals being added in the form of oxides to the powder subjected to sintering.

Abstract: A control device (10) for an electrical switchgear with three switching positions including a closed position, an open position and an earthing position. The switchgear includes a main shaft (14) and a drive shaft (28). The control device includes a mode selector lever (30) designed to select one operating mode among a motor driven switching mode, a manual switching mode between the open position and the closed position of the electrical switchgear, and a manual switching mode between the open position and the earthing position of the electrical switchgear. The mode selector lever has an opening with a curved contour, and the control device includes a cam disk (50) with a cam (54) capable of moving inside the opening (40). The control device may be applied to an isolating switch.

Abstract: An electrical contact member, suitable for electrically interconnecting two conductive members in series, which members can move relative to each other and are part of an electrical apparatus. The electrical contact includes a strength-imparting base layer made of an electrically conductive material, and a coating layer formed from metallic silver and configured to come into contact with the two electrically conductive members. The coating layer has a micro-structure formed by pure silver crystals, with a presence of nodules made of silver and of an additional metallic material formed by at least one additional metal that is different from silver.

Abstract: A sensor for picking up partial discharges in an electrical equipment tank filled with a dielectric fluid includes an antenna responsive to the electromagnetic waves generated by such partial discharges. In the sensor, the antenna is formed by two electrodes that are separated from each other by a dielectric resonator. With this arrangement, the sensor has improved sensitivity in the UHF range, while being of dimensions that are considerably smaller than dimensions of a conventional antenna for use in the UHF range.

Abstract: The invention relates to a method for producing a thread in a bore (2) by remote automatic machining characterized in that said method consists in introducing into the bore (2) an electrode (11) provided with a thread (20) whose shape and dimensions are pre-determined according to the shape and dimensions of an inside thread to be produced, in machining the internal threads by electroerosion displacing the electrode (11) in an orbital manner in the bore (2) according to a predetermined number of operations and in adjusting the machining parameters according to each operation. A device for carrying out said method is also disclosed.

Abstract: The invention relates to a hybrid circuit-breaker which, for each pole, comprises a dielectric-gas interrupting chamber (1) which contains a first contact (1A) and a moving second contact (1B) that are disposed longitudinally to a first axis (AA?) and in which the first contact (1A) is connected to a first terminal (3A) of the network, said interrupting chamber (1) being connected in series with a vacuum bottle (2) which contains a fixed contact (2A) and a moving contact (2B) that are disposed longitudinally to a second axis (BB?) and in which the fixed contact (2A) is connected to a second terminal (3B) of the network, actuating means acting via a single control (4) to move said moving contacts between respective open positions and respective closed positions.

Abstract: The invention provides a method of detecting partial discharges in an electrical appliance insulated in a receptacle and a system of diagnosing the state of the appliance using this method. With the help of an UHF antenna placed in the receptacle of the appliance, the method includes analyzing the spectrum (RS1) of the electromagnetic signal picked up by the antenna and of identifying within the spectrum one or more frequencies of interest (B1, B2), for each of which the signal has an amplitude greater than a predetermined threshold value. To identify the frequency/frequencies of interest, the spectrum of the signal received by the antenna is compared with a reference spectrum (RS2).

Abstract: A method of detecting and localizing a source of partial discharge in an electrical apparatus placed in an enclosure containing an acoustically-conductive fluid.

Abstract: This invention relates to a method for detection of the position of a wave front in a signal received by a detector. This method consists of: converting the signal into a digital signal, defining a working group of N successive samples in the digital signal, and possibly processing the samples in the working group, calculating the energy of the signal from the processed samples in the working group, if any, in terms of the root mean square over a sliding window, the window comprising an optimum number Lopt of samples (Lopt is less than N), the position of the wave front corresponding to the position of the sample for which the energy of the signal exceeds a threshold D that depends on the value of the energy of the signal previously at the wave front, for the first time.

Abstract: A protection system for an electrical power line system of the type comprising radially connected power line sections, wherein a first electrically upstream one of the line sections is connectable to a power source. The protection system comprises at least one relay installed at or near at least the upstream end of each line section to protect that line section, each relay having an associated circuit breaker. The relays are provided with a first set of accelerated overcurrent functions and a second set of under-current/under-voltage functions, the relays being directional and the first and second sets of functions being time graded in reverse to each other.

Abstract: A support for high-voltage or medium-voltage electrical plant comprises four columns placed on a support surface and connected in pairs by crossmember assemblies. The columns are each articulated to rotate about a first horizontal axis at their end resting on the support surface and about a second horizontal axis on a top crossmember at their other end. The first and second axes are parallel. Two opposite crossmember assemblies allow the two columns connected by one or the other of these two assemblies to move in a stable manner in their rotation plane.

Abstract: A sensor for picking up partial discharges in an electrical equipment tank filled with a dielectric fluid includes an antenna responsive to the electromagnetic waves generated by such partial discharges. In the sensor, the antenna is formed by two electrodes that are separated from each other by a dielectric resonator. With this arrangement, the sensor has improved sensitivity in the UHF range, while being of dimensions that are considerably smaller than dimensions of a conventional antenna for use in the UHF range.

Abstract: A control device (10) for an electrical switchgear with three switching positions, of the type comprising a closed position, an open position and an earthing position, comprising a main shaft (14) and a drive shaft (28), comprises: a mode selector lever (30) designed to select one operating mode among the <<motor driven switching mode>>, the <<manual switching mode between the open position and the closed position of the electrical switchgear>> and the <<manual switching mode between the open position and the earthing position of the electrical switchgear>>, that comprises an opening with a curved contour, and a cam disk (50) with a cam (54) capable of moving inside said opening (40). Application to an isolating switch.

Abstract: A device for the actuation of the movable contacts of a hybrid circuit breaker allows the following time diagram to be implemented: command the opening of the interrupting chamber, offset the opening of the vacuum switch so as to allow the interrupting chamber contacts to separate at a minimum speed and in a way that is synchronous with the separation of the vacuum switch contacts, close the vacuum switch while keeping the interrupting chamber in the open position. Moreover, closing the interrupting chamber does not act upon the contacts of the vacuum switch. The actuation device can be found in a number of embodiments, and allows the vacuum interrupter to be controlled when the circuit breaker is triggered or closed.

Abstract: The invention relates to an on-load transformer tap changing system wherein the secondary or primary of a transformer comprises at least one first and one second taps (p1, p2). A main connection circuit (tra-I2) is used for the permanent connection of the first tap (p1) or the second tap (p2) to an output terminal (b2) of the secondary or primary of the transformer. Secondary connection circuits (I1, I3) are each used to connect a tap (p1, p2) temporarily and directly to said output terminal (b2) of the secondary or primary of the transformer. Each of said connection circuits (I1, tra-I2, I3) comprises one or more insulated gate bipolar transistors and the system can be controlled without zero current value transition detection in the secondary winding. Application: Power transformers.