Abstract: A switch unit is connected between a first node electrically connected to a power source and a second node electrically connected to a load circuit which receives power supplied from the power source. As a current suppression element is connected to the switch unit in parallel. A fault sensing unit senses abnormality in an electrically conducting circuit formed by electrically interconnecting the first node and the second node. When a closing operation of a switchgear is performed, a switching command unit conducts an abnormality diagnosis in a first state in which the switch unit is controlled so that an impedance between the first node and the second node has a first value, and when no abnormal state is sensed in the abnormality diagnosis, the switching command unit controls the switch unit to establish a second state in which the impedance is equal to or smaller than the first value.

Abstract: A switching device includes: a first contact; a second contact; and a fault detection circuit. The second contact includes a fixed contactor and a movable contactor. When the second contact is energized due to an operation of opening the first contact, the movable contact is separated from the fixed contact by an electromagnetic force generated by a flow of currents in opposite directions through the pair of current-carrying electrodes, and a discharge switch is formed between the movable contact and the fixed contact that are separated. The switching device further includes: a first arc runner electrically connected to the fixed contactor for driving, by an electromagnetic force, arc discharge that occurs when the second contact is opened; and a second arc runner electrically connected to the movable contactor.

Abstract: A switch includes: a fixed contact including a fixed contact point; a movable contact including a movable contact point; a magnetic field generating member including a first magnetic pole surface and a second magnetic pole surface; a main yoke including a first connection portion that is connected to the second magnetic pole surface, extends in a third direction from the second magnetic pole surface, and projects to one side and another side in the third direction farther than the magnetic field generating member and the movable contact in the third direction, and an arm portion extending in a second direction from both end portions of the first connection portion along the third direction and disposed on both sides of the magnetic field generating member and the movable contact along the third direction; and an auxiliary yoke directly connected to the first magnetic pole surface.

Abstract: The present disclosure includes: a power generator; and a power line through which power generated by the power generator is transmitted to a load. The power line between the power generator and the load is provided with: a current limitation device configured to, when detecting occurrence of a fault current, limit the fault current; and a current interruption device configured to interrupt current heading for the load, in conjunction with the limitation of the fault current performed by the current limitation device.

Abstract: The semiconductor circuit breaker includes a semiconductor switch unit connected to an AC circuit, and a phase control unit that controls conduction and non-conduction of the semiconductor switch unit by the control signal. The phase control unit includes an accident detection unit to detect an accident based on a current detected from the AC circuit, a zero point detection unit to detect a current zero point based on the current detected from the AC circuit, and a control signal output unit to output the control signal for setting the semiconductor switch unit to be non-conductive when the accident detection unit detects the accident or when the zero point detection unit detects the current zero point in response to a command to cut off the current.

Abstract: The present disclosure includes: a power generator; and a power line through which power generated by the power generator is transmitted to a load. The power line between the power generator and the load is provided with: a current limitation device configured to, when detecting occurrence of a fault current, limit the fault current; and a current interruption device configured to interrupt current heading for the load, in conjunction with the limitation of the fault current performed by the current limitation device.

Abstract: In order to provide a DC interrupting device that does not easily cause erroneous melting of current-limiting fuses at normal times with no fault current, and that can also deliver good current-limiting performance at the time of occurrence of fault current, the DC interrupting device includes: a (k?1)th current path including a (k?1)th current-limiting fuse, where k is an integer of not less than two and not more than N, and N is an integer of not less than two; and a kth current path connected in parallel to the (k?1)th current path and including a kth current-limiting fuse. The inductance value of the inductance component of the kth current path is higher than the inductance value of the inductance component of the (k?1)th current path.

Abstract: The semiconductor circuit breaker includes a semiconductor switch unit connected to an AC circuit, and a phase control unit that controls conduction and non-conduction of the semiconductor switch unit by the control signal. The phase control unit includes an accident detection unit to detect an accident based on a current detected from the AC circuit, a zero point detection unit to detect a current zero point based on the current detected from the AC circuit, and a control signal output unit to output the control signal for setting the semiconductor switch unit to be non-conductive when the accident detection unit detects the accident or when the zero point detection unit detects the current zero point in response to a command to cut off the current.

Abstract: A DC circuit breaker includes: a mechanical switch provided on an electrical path through which a direct current flows; and a semiconductor switch connected in parallel with the mechanical switch. The mechanical switch includes a gas disconnector and a vacuum circuit breaker connected in series. Normally, the direct current flows through the mechanical switch. When interrupting the direct current, the vacuum circuit breaker is made nonconductive to allow the direct current to be commutated to the semiconductor switch, and subsequently the gas disconnector and the semiconductor switch are made nonconductive. A vacuum circuit breaker having a low withstand voltage can be used.

Abstract: In order to provide a DC interrupting device that does not easily cause erroneous melting of current-limiting fuses at normal times with no fault current, and that can also deliver good current-limiting performance at the time of occurrence of fault current, the DC interrupting device includes: a (k?1)th current path including a (k?1)th current-limiting fuse, where k is an integer of not less than two and not more than N, and N is an integer of not less than two; and a kth current path connected in parallel to the (k?1)th current path and including a kth current-limiting fuse. The inductance value of the inductance component of the kth current path is higher than the inductance value of the inductance component of the (k?1)th current path.

Abstract: A circuit closer includes: a vacuum interrupter in which one of a pair of electrodes oppositely disposed in a vacuum vessel, wherein a gap d between the pair of electrodes always satisfies d>0, and a gap d1 between the pair of electrodes in a state in which closing of a circuit is completed, is shorter than a distance d2 at which insulation between the pair of electrodes is broken down by a charge voltage V of the circuit that is to be closed, and is longer than a distance d3 at which the pair of electrodes are bridged by a deposition of an electrode metal after a closing operation, the deposition resulting from evaporation caused by heat of an arc generated when the circuit is closed.

Abstract: A power device, which includes: an energizing conductor; a power generation unit configured to generate power that is induced by a magnetic flux of a current flowing through the energizing conductor; a power device unit configured to use the power generated in the power generation unit as a power source; a short-circuit switch capable of short-circuiting an output from the power generation unit; and a sealed container in which the energizing conductor, the power generation unit and the power device unit are included, and an insulating fluid is enclosed in the sealed container. This power device is provided as a highly reliable power device, which is used in an AC power system and does not induce an excessive voltage in the power generation unit when the power device unit is stopped in the state where the energized state of the energizing conductor is maintained.

Abstract: A power device is provided, which includes: an energizing conductor; a power generation unit configured to generate power that is induced by a magnetic flux of a current flowing through the energizing conductor; a power device unit configured to use the power generated in the power generation unit as a power source; a short-circuit switch capable of short-circuiting an output from the power generation unit; and a sealed container in which the energizing conductor, the power generation unit and the power device unit are included, and an insulating fluid is enclosed in the sealed container. This power device is provided as a highly reliable power device, which is used in an AC power system and does not induce an excessive voltage in the power generation unit when the power device unit is stopped in the state where the energized state of the energizing conductor is maintained.

Abstract: In a DC circuit breaker device, first and second semiconductor switches are connected in series on a main circuit line such that current-carrying directions of the switches are opposite to each other. A first diode is connected in anti-parallel with the first semiconductor switch, and a second diode is connected in anti-parallel with the second semiconductor switch. First and second mechanical circuit breakers are connected in series with each other and in parallel with the whole of the first and semiconductor switches. First and second backward current generation circuits are connected in series with each other and in parallel with the whole of the first and second mechanical circuit breakers. An injection switch is connected between a node between the first and second mechanical circuit breakers and a node between the first and second backward current generation circuits.

Abstract: A DC circuit breaker includes: a mechanical switch provided on an electrical path through which a direct current flows; and a semiconductor switch connected in parallel with the mechanical switch. The mechanical switch includes a gas disconnector and a vacuum circuit breaker connected in series. Normally, the direct current flows through the mechanical switch. When interrupting the direct current, the vacuum circuit breaker is made nonconductive to allow the direct current to be commutated to the semiconductor switch, and subsequently the gas disconnector and the semiconductor switch are made nonconductive. A vacuum circuit breaker having a low withstand voltage can be used.

Abstract: A circuit closer includes: a vacuum interrupter in which one of a pair of electrodes oppositely disposed in a vacuum vessel, wherein a gap d between the pair of electrodes always satisfies d>0, and a gap d1 between the pair of electrodes in a state in which closing of a circuit is completed, is shorter than a distance d2 at which insulation between the pair of electrodes is broken down by a charge voltage V of the circuit that is to be closed, and is longer than a distance d3 at which the pair of electrodes are bridged by a deposition of an electrode metal after a closing operation, the deposition resulting from evaporation caused by heat of an arc generated when the circuit is closed.

Abstract: The present invention relates to an arc-extinguishing insulation material molded product provided in the vicinity of a contact point between contactors in a gas circuit breaker. The arc-extinguishing insulation material molded product includes a polymer which contains a carbon-oxygen bond in the main chain, and in which a part of or all of terminal atoms are non-hydrogen atoms.

Abstract: The present invention relates to an arc-extinguishing insulation material molded product provided in the vicinity of a contact point between contactors in a gas circuit breaker. The arc-extinguishing insulation material molded product includes a polymer which contains a carbon-oxygen bond in the main chain, and in which a part of or all of terminal atoms are non-hydrogen atoms.

Abstract: In a DC circuit breaker device, first and second semiconductor switches are connected in series on a main circuit line such that current-carrying directions of the switches are opposite to each other. A first diode is connected in anti-parallel with the first semiconductor switch, and a second diode is connected in anti-parallel with the second semiconductor switch. First and second mechanical circuit breakers are connected in series with each other and in parallel with the whole of the first and semiconductor switches. First and second backward current generation circuits are connected in series with each other and in parallel with the whole of the first and second mechanical circuit breakers. An injection switch is connected between a node between the first and second mechanical circuit breakers and a node between the first and second backward current generation circuits.

Abstract: A gas circuit breaker includes: a pair of electrodes provided so as to be able to come in contact with and separate from each other; and an insulating material that is placed so as to generate a decomposition gas in response to a direct or indirect action from an arc occurring between the pair of electrodes when a current is broken, wherein the decomposition gas generated from the insulating material when the current is broken is configured to be utilized for extinguishing the arc, and wherein an ablative material that does not include hydrogen atoms but has a carbon-oxygen bond in a main chain or ring part is used as the insulating material.