Abstract: There is provided a method for determining an abnormality during operation of a high voltage disconnect switch, the method comprising: determining a current position of an arm of the high voltage disconnect switch operatively connected to a motor, the motor being operated for driving the arm of the high voltage disconnect switch; determining a torque of the motor corresponding to the current position of the arm; comparing the torque of the motor to a torque threshold for the current position of the arm; and outputting an abnormality signal based on the comparison.

Abstract: There is provided a method for determining an abnormality during operation of a high voltage disconnect switch, the method comprising: determining a current position of an arm of the high voltage disconnect switch operatively connected to a motor, the motor being operated for driving the arm of the high voltage disconnect switch; determining a torque of the motor corresponding to the current position of the arm; comparing the torque of the motor to a torque threshold for the current position of the arm; and outputting an abnormality signal based on the comparison.

Abstract: A hybrid circuit-breaker for interrupting currents having high DC components, said hybrid circuit-breaker comprising a compressed-air circuit-breaker that re-closes automatically, and a sulfur hexafluoride circuit-breaker, the circuit-breakers being disposed in series.

Abstract: A high-voltage circuit-breaker has an interrupting chamber comprising a gas-tight cylindrical casing filled with a gas having good insulative properties such as sulfur hexafluoride. The casing contains a fixed permanent contact, a fixed arc contact and a mobile assembly comprising permanent contacts and arc contacts and associated with a gas blast assembly. The chamber also contains a carbon-based resistor having a resistance of approximately 500 ohms connected in parallel with the circuit-breaker contacts when the arc contacts are opened by an auxiliary switch. This resistor is connected in series with an arrangement of varistors, the resulting combination being disposed inside the casing and connected in series with the auxiliary switch. Opening of the auxiliary switch is effected by opening of the circuit-breaker. The volume of the resistor is greater than that of the arrangement of varistors by a factor of at least five.

Abstract: A high tension circuit-breaker has an insulating case filled with a dielectric gas such as SF.sub.6. A high capacitance capacitor and at least a varistor are electrically interconnected in parallel and are connected to a first terminal. The capacitor and varistor are associated with an insertion mechanism which momentarily inserts the capacitor and varistor in parallel with the arcing contacts during circuit-breaker disengagement or engagement. The insulating case is extended by at least one conductive case housing both the capacitor and at least part of the varistor.

Abstract: In a sulfur hexafluoride high-tension circuit-breaker, a condenser/evaporator (8), disposed beneath and in communication with the inside of a support column, is partially filled with an insulating material (11), having at least one well (10) formed therein, with a heater element (9) being disposed inside the well, the surface of the insulating material (11) being connected to the bottom of the well via ducts (13, 14).

Abstract: A high voltage sulfur hexafluoride circuit-breaker capable of operating at low outside temperatures and comprising at least one current-interrupting chamber comprising a sealed insulating enclosure containing a fixed contact inside a blast nozzle and a set of moving contacts associated with an operating member, the circuit-breaker including the improvement of means for maintaining a quantity of liquefied gas in the vicinity of the contact separation zone while the circuit-breaker is in the closed position.

Abstract: A puffer type liquefied-gas self-injection circuit breaker, used for the interruption at low temperature of a high current carried by a high-voltage power line. The circuit breaker comprises a first fixed contact and a compression chamber. The compression chamber has a bottom part which is fixed and an upper part of which is movable in the axial direction with respect to the bottom part. The upper part of the compression chamber comprises a second contact and an envelope concentrically disposed thereabout. An insulating nozzle is formed in a top portion of the envelope. The internal wall of the envelope is so shaped as to exactly match the external profile of the bottom part of the compression chamber. The breaker is also equipped with a liquefied-gas self-injection system which injects the liquefied-gas from their storage tank via a feed line and valve directly onto the electric arc formed at the moment of current interruption.

Abstract: A sulfur hexafluoride circuit-breaker for operating in a very low temperature environment, the circuit-breaker being of the type comprising a sealed enclosure filled with sulfur hexafluoride and closed by first and second end plates, a set of fixed contacts, a set of moving contacts driven by an operating rod, a blast volume which is mechanically compressed when the operating rod is displaced to open the circuit-breaker, and blast nozzle for directing the said compressed gas from said volume onto the arc, the circuit-breaker including the improvement of means for creating an arc in said blast volume during a portion of the time that the moving assembly is moving, by diverting the current to be interrupted so that it flows through two parts constituting two electrodes.