Abstract: A breaking device includes an interrupting section including interrupting units in which main interrupters, impedance circuits, and unit arresters are connected in parallel to each other, the main interrupters being connected in series, a resonant circuit section including a reactor, a capacitor, and a closing switch and connected in parallel to the interrupting section, and an all-point arrester connected in parallel to the interrupting section via the reactor. The clamping voltages of the unit arresters are equal among the interrupting units, and are in the range of 1.1 to 1.6 times the value obtained by dividing the clamping voltage of the all-point arrester by the number of the interrupting units connected in series in the interrupting section.

Abstract: A direct-current circuit breaker that includes: an interrupter; a resonance circuit including a capacitor, a reactor, and an activation switch; a voltage detection circuit; a charging circuit including a charging resistor and a charging switch; and a control circuit. The control circuit closes the charging switch to charge the capacitor, and thereafter, the control circuit opens the charging switch when the charging voltage exceeds a first voltage value, and closes the charging switch when the charging voltage falls below a second voltage value that is smaller than the first voltage value.

Abstract: A direct-current circuit breaker includes a circuit breaker unit and a circuit unit that generates an oscillating current. The circuit unit includes a capacitor and a reactor, a high-speed closer, and a lightning arrester. The circuit breaker unit and the high-speed closer are aligned in a first direction with a distance therebetween that is equal to or longer than a certain spatial distance. The capacitor and the lightning arrester are aligned in a second direction intersecting the first direction with a distance therebetween that is equal to or longer than the spatial distance. A combination of the circuit breaker unit with the high-speed closer and a combination of the capacitor with the lightning arrester are aligned in a third direction intersecting the first direction and the second direction with a distance therebetween that is equal to or longer than the spatial distance.

Abstract: A breaking device includes an interrupting section including interrupting units in which main interrupters, impedance circuits, and unit arresters are connected in parallel to each other, the main interrupters being connected in series, a resonant circuit section including a reactor, a capacitor, and a closing switch and connected in parallel to the interrupting section, and an all-point arrester connected in parallel to the interrupting section via the reactor. The clamping voltages of the unit arresters are equal among the interrupting units, and are in the range of 1.1 to 1.6 times the value obtained by dividing the clamping voltage of the all-point arrester by the number of the interrupting units connected in series in the interrupting section.

Abstract: A direct-current circuit breaker includes a first main circuit breaker inserted into a first direct-current line, a resonance circuit connected in parallel to the first main circuit breaker, a MOSA connected in parallel to the first main circuit breaker via the resonance circuit, a second main circuit breaker inserted into a second direct-current line, a switch connected in series to the second main circuit breaker, a resonance circuit connected in parallel to the second main circuit breaker, and a MOSA connected in parallel to the second main circuit breaker via the resonance circuit. The second direct-current line is a line that branches off from the first direct-current line and returns to the first direct-current line. The switch is inserted upstream of the second direct-current line.

Abstract: A direct-current breaking device includes a main circuit breaker inserted on a DC line, a resonant circuit connected in parallel with the main circuit breaker, and a MOSA connected in parallel with the main circuit breaker via the resonant circuit. The resonant circuit includes first, second, third, and fourth switching elements, a capacitor, and a reactor. A first circuit unit including the first switching element and the second switching element connected in series with each other, and a second circuit unit including the third switching element and the fourth switching element connected in series with each other are connected in parallel. The capacitor is connected between a connection point of the first switching element and the second switching element and a connection point of the third switching element and the fourth switching element to constitute a bridge circuit. The bridge circuit and the reactor are in series with each other.

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 direct-current circuit breaker includes a circuit breaker unit and a circuit unit that generates an oscillating current. The circuit unit includes a capacitor and a reactor, a high-speed closer, and a lightning arrester. The circuit breaker unit and the high-speed closer are aligned in a first direction with a distance therebetween that is equal to or longer than a certain spatial distance. The capacitor and the lightning arrester are aligned in a second direction intersecting the first direction with a distance therebetween that is equal to or longer than the spatial distance. A combination of the circuit breaker unit with the high-speed closer and a combination of the capacitor with the lightning arrester are aligned in a third direction intersecting the first direction and the second direction with a distance therebetween that is equal to or longer than the spatial distance.

Abstract: A DC circuit breaker includes a fuse unit to interrupt a large current with a fuse, and the fuse unit includes a high-speed disconnector that is connected in parallel to the fuse and is opened when a fault current is detected.

Abstract: A direct-current circuit breaker includes a first main circuit breaker inserted into a first direct-current line, a resonance circuit connected in parallel to the first main circuit breaker, a MOSA connected in parallel to the first main circuit breaker via the resonance circuit, a second main circuit breaker inserted into a second direct-current line, a switch connected in series to the second main circuit breaker, a resonance circuit connected in parallel to the second main circuit breaker, and a MOSA connected in parallel to the second main circuit breaker via the resonance circuit. The second direct-current line is a line that branches off from the first direct-current line and returns to the first direct-current line. The switch is inserted upstream of the second direct-current line.

Abstract: A direct-current breaking device includes a main circuit breaker inserted on a DC line, a resonant circuit connected in parallel with the main circuit breaker, and a MOSA connected in parallel with the main circuit breaker via the resonant circuit. The resonant circuit includes first, second, third, and fourth switching elements, a capacitor, and a reactor. A first circuit unit including the first switching element and the second switching element connected in series with each other, and a second circuit unit including the third switching element and the fourth switching element connected in series with each other are connected in parallel. The capacitor is connected between a connection point of the first switching element and the second switching element and a connection point of the third switching element and the fourth switching element to constitute a bridge circuit. The bridge circuit and the reactor are in series with each other.

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 DC circuit breaker includes a fuse unit to interrupt a large current with a fuse, and the fuse unit includes a high-speed disconnector that is connected in parallel to the fuse and is opened when a fault current is detected.

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 direct-current circuit includes: a breaker that is inserted into the direct-current line and becomes a path for direct current when in a steady state; a resonance circuit connected in parallel with the breaker and superimposing resonance current on the direct current; and a first disconnector and a second disconnector connected to first and second connection points of the breaker and the resonance circuit, respectively, and forming a path for the direct current together with the breaker. The resonance circuit includes a series circuit that includes a capacitor and a reactor and generates the resonance current, a charging resistor for charging the capacitor with a direct-current potential of the direct-current line, a high-speed switch connected in series with the series circuit on the capacitor side and superimposing the resonance current on the direct current, and an arrester connected in parallel with the capacitor and the high-speed switch.

Abstract: A direct current circuit breaker used in a self-commutated direct current power transmission system includes a high-speed circuit breaker and a low-speed circuit breaker connected in series. The high-speed circuit breaker includes a high-speed circuit breaker interruption unit to interrupt a DC current flowing through a direct current line when a fault has occurred, and a current limiting element connected in parallel therewith. The low-speed circuit breaker includes a low-speed circuit breaker interruption unit to interrupt a DC current when a fault has occurred. A time required for the high-speed circuit breaker interruption unit to interrupt the DC current is shorter than a time required for the low-speed circuit breaker interruption unit. The low-speed circuit breaker interruption unit completes interruption of the DC current before a voltage applied to the current limiting element becomes lower than a minimum voltage allowable for the system.

Abstract: A wind power generation system according to the present invention includes: a DC bus; a plurality of feeders connected to the DC bus for transmitting DC powers to the DC bus; a plurality of wind power generators; a plurality of AC/DC converters connected one by one to each of the wind power generators for converting AC powers generated by the connected wind power generators, into DC powers, and outputting the DC powers to the feeders; and a DC breaker and a diode, which serve as a current limiting unit installed on each of the feeders for preventing a DC current from flowing from the DC bus into the feeder.

Abstract: A wind power generation system according to the present invention includes: a DC bus; a plurality of feeders connected to the DC bus for transmitting DC powers to the DC bus; a plurality of wind power generators; a plurality of AC/DC converters connected one by one to each of the wind power generators for converting AC powers generated by the connected wind power generators, into DC powers, and outputting the DC powers to the feeders; and a DC breaker and a diode, which serve as a current limiting unit installed on each of the feeders for preventing a DC current from flowing from the DC bus into the feeder.

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.