Abstract: A puffer type gas circuit breaker has a piston, which is connected with a center shaft via a link mechanism. At an initial stage of an interruption operation, the link mechanism drives a puffer cylinder and the piston both in an interruption direction while maintaining an almost constant distance therebetween. Even when a pressure rise occurs in a compression chamber by the heat of an arc generated in accordance with opening between a fixed arc contact and a movable arc contact, the pressure rise does not become an operation counterforce to an operator. At a final stage of the interruption operation where the fixed arc contact is removed from a throat of an insulating nozzle, the link mechanism drives the piston in an almost stopped status.

Abstract: A puffer type gas circuit breaker has a piston, which is connected with a center shaft via a link mechanism. At an initial stage of an interruption operation, the link mechanism drives a puffer cylinder and the piston both in an interruption direction while maintaining an almost constant distance therebetween. Even when a pressure rise occurs in a compression chamber by the heat of an arc generated in accordance with opening between a fixed arc contact and a movable arc contact, the pressure rise does not become an operation counterforce to an operator. At a final stage of the interruption operation where the fixed arc contact is removed from a throat of an insulating nozzle, the link mechanism drives the piston in an almost stopped status.

Abstract: A current collector, in which contact portions are free from dissolved loss even both fixed and moving contacts slidingly contact with each other, and durability as well as a current-carrying perfomance is improved, including a container, which is filled with an insulating arc-extinguishing medium and in which a cylindrical-shaped fixed contact and an torus-shaped contact disposed concentrically with the fixed contact and adapted to come into fitting contact with the fixed contact to carry current are received, and a torus-shaped current collecting member formed from a conductive material and provided on a contact portion of the torus-shaped contact.

Abstract: A highly reliable gas circuit breaker capable of improving the braking performance and the insulating performance and a gas circuit breaker capable of allowing a stress acting on the supporting member of the electrode are provided. The gas circuit breaker comprising a grounded tank filled with an insulation medium; a movable electrode arranged inside the grounded tank; a fixed electrode which is supported through an insulator supporting member inside the grounded tank and disposed detachably from and oppositely to the movable electrode; and electric conductive parts individually provided in the movable electrode and the fixed electrode, wherein the insulator supporting member is a solid cone and supports the fixed electrode in an upper side of a central axis of the grounded tank.

Abstract: A current collector, in which contact portions are free from dissolved loss even when both fixed and moving contacts slidingly contact with each other, and durability as well as a current-carrying performance is improved, including a container, which is filled with an insulating arc-extinguishing medium and in which a cylindrical-shaped fixed contact and an torus-shaped contact disposed concentrically with the fixed contact and adapted to come into fitting contact with the fixed contact to carry current are received, and a torus-shaped current collecting member formed from a conductive material and provided on a contact portion of the torus-shaped contact.

Abstract: A gas-insulated switchgear includes a sealed vessel filled with an insulating gas, a circuit breaker held in the sealed vessel, and a branch pipe attached to a lower part of the sealed vessel right below the circuit breaker. The branch pipe defines a hand hole for use in inspecting the circuit breaker, provides a place for installing an absorbent container and forms a foreign matter collecting space.

Abstract: A gas-insulated switchgear includes a sealed vessel filled with an insulating gas, a circuit breaker held in the sealed vessel, and a branch pipe attached to a lower part of the sealed vessel right below the circuit breaker. The branch pipe defines a hand hole for use in inspecting the circuit breaker, provides a place for installing an absorbent container and forms a foreign matter collecting space.

Abstract: A compact-sized gas insulated switchgear accommodates components and devices constituting its line side unit into one container. Arresters and cable heads are accommodated in a lower section of the line side unit, and a circle connecting centers of respective arresters and cable heads arranged therein is concentric with a cylindrical section of the line side unit container.

Abstract: A gas insulated switchgear of the present invention, a plurality of disconnect switches are provided on a line connecting a bus line to a circuit-breaker in such a manner as to be arranged in both a main bus unit, a breaker unit or in both a first and second insulating gas sections. Accordingly, when an inconvenience occurs in the gas insulated switchgear apparatus and the exchange work of a unit is required, it is possible to exchange the inconvenient damaged unit only by turning the circuit including the inconvenient damaged unit into power supply interruption, that is, without turning a normal circuit unit into power supply interruption.

Abstract: A gas insulated switchgear includes a bus unit, a breaker unit and a line side unit. An insulating spacer structure attaching at least two of the units together includes an inner flange on a first unit, an outer flange on a second unit, and an insulating spacer positioned between the first and second units. Closed end tapped holes are formed in the inner flange and idle holes are formed in the outer flange, and tapped holes with a larger diameter than that of the tapped holes of the inner flange are formed in the insulating spacer.

Abstract: A gas insulated switching apparatus has lightning arrestors in a line side unit. Each lightning arrestor is mounted to be moved linearly into and out of connection with a corresponding conductor. Specifically, the cover which supports the lightning arrestor is disposed beneath the bottom plate of the vessel of the line side unit. The lightning arrestors are connected to a monitor of an operating device beneath the line side unit. Since the lower portion of the lightning arrestors are connected to the monitor, the length of the connection lines is made sufficiently short.

Abstract: A gas insulated switch gear has a main bus unit, a circuit breaker unit and a line unit. The line unit has a top plate with a hole through which a potential transformer is inserted into the inside of the line unit and an adapter cover fixed to the potential transformer is connected to the top plate.

Abstract: A gas insulated switchgear includes a bus unit, a breaker unit and a line side unit. An insulating spacer structure attaching at least two of the units together includes an inner flange on a first unit, an outer flange on a second unit, and an insulating spacer positioned between the first and second units. Closed end tapped holes are formed in the inner flange and idle holes are formed in the outer flange, and tapped holes with a larger diameter than that of the tapped holes of the inner flange are formed in the insulating spacer.

Abstract: A current limiter used for stable control of an electric power system, and particularly applied to a high voltage of the electric power system, has a reduced voltage for suppressing the overcurrent of the electric power system. The current limiter is not enlarged so that the current limiter secures the insulation of the voltage withstanding level, and the current limiter is easy to be introduced to the system. A limiting device is inserted between a low potential terminal of a winding of a star-connection of a three-phase transformer that has at least one winding of the star-connection and a ground point.

Abstract: A current limiter used for stable control of an electric power system, and particularly applied to a high voltage of the electric power system, has a reduced voltage for suppressing the overcurrent of the electric power system. The current limiter is not enlarged so that the current limiter secures the insulation of the voltage withstanding level, and the current limiter is easy to be introduced to the system. A limiting device is inserted between a low potential terminal of a winding of a star-connection of a three-phase transformer that has at least one winding of the star-connection and a ground point.

Abstract: An electric power flow controller for controlling an electric power flow of a power system includes a semiconductor switch for controlling a series reactance of the power system. The electric power flow controller includes a first winding having at least one Y-connection, a second winding mating with the first winding, an electric power flow compensator connected in series to the Y-connection of the first winding and for compensating a transmission state of the electric power system. The electric power flow compensator provides a compensating capacitor inserted onto an electric power line. The compensation of the capacitor is controlled by the semiconductor switch. The semiconductor switch keeps an application of a voltage that is equal to or lower than a voltage to ground of the electric power line.

Abstract: A plurality of solid-state switches are provided in parallel with a main circuit switch. A main circuit current is detected by a first current detecting device. A current flowing in each of the plurality of solid-state switches is detected by a second current detecting device. Based on the detected currents of the first and second current detecting devices, the main circuit switch is commanded to open and each solid-state switch is commanded to close by a control circuit, when a fault is detected by a fault detecting circuit. At this point of the process when the main circuit switch is opened, when a commutation anomaly is detected by a commutation detecting circuit, the conducting status of each solid-state switch is maintained. When the commutation achieves a normal status, each solid-state switch is interrupted and circuit breaking, at the point the capability of each solid-state switch is exceeded, is prevented.

Abstract: A ground fault current limiter, in which reactors are connected in series to a neutral point for compensating for capacitances to ground of a power switches capable of turning ON/OFF at a high speed are connected in parallel with respective reactors, occurrence of a ground fault is detected from a phase difference between a zero-phase sequence current and a zero-phase sequence voltage at time of sampling, an optimal compensation quantity of capacitances to ground is computed based on the zero-phase sequence current and the zero-phase sequence voltage at time of occurrence of a ground fault, and ON/OFF of the switches are controlled thereby to alter the reactor quantity so as to correspond to the compensation quantity.

Abstract: A solid-state switch has a plurality of gate turn-off thyristors connected in the rungs of a ladder circuit and a plurality of diodes connected in the side rails of the ladder circuit. The anode of the first gate turn-off thyristor is connected to the cathodes of the first and second diodes, the cathode of the first gate turn-off thyristor is connected to the anodes of the third and fourth diodes. The cathode of the second gate turn-off thyristor is connected to the anode of the second diode and the anode of the fifth diode, the anode of the second gate turn-off thyristor is connected to the cathode of the fourth diode and the cathode of the sixth diode. The anode of the first diode and the cathode of the third diode are connected together at a common point, which is selected to be one terminal of the switch.