Hitachi, Ltd.

Other

Chubu Electric Power Company, Inc.

Hitachi Electric Systems Co., Ltd.

Yukio Kurosawa

Masanori Tsukushi

Osamu Koyanagi

Yoshimi Hakamata

Tadashi Sato

Akira Hashimoto

Kunio Hirasawa

Yoshitaka Kojima

Hiroyuki Sugawara

Youichi Ohshita

Katsuhiro Komuro

Kiyoji Iwashita

Shunkichi Endo

Tokio Yamagiwa

Hiroshi Arita

Toru Tanimizu

Yasunori Ohno

Yoshihito Asai

Tomoe Kurosawa

Yoshio Koguchi

Kogi Ishikawa

Yukio Kawakubo

Yasuharu Seki

Goro Daimon

Katsuichi Kashimura

Akira Wada

Isao Nishida

Eisaku Mizufune

Kastuichi Kashimura

Kenji Tsuchiya

Nobuo Abe

Ryuji Watanabe

Hisashi Ando

Haruo Honda

Noriaki Munakata

Shigetoshi Oouchi

Shunkichi Endoo

Minori Sato

Masaki Shinohara

Minori Satoh

Morihisa Matumoto

Kouji Suzuki

Jun Ozawa

Toshiaki Ueda

Takashi Sato

Fumihiro Endo

Toshio Ishikawa

Keiichi Kuniya

Isao Takahashi

Junzo Kida

Tooru Tanimizu

Hiroaki Kojima

Makoto Yano

Kiyoshi Okumura

Kenichi Natsui

Seiki Shimizu

Ken-ichi Natsui

Kazuhiro Saito

Masaru Watanabe

Yoshiyuki Kubota

Hideaki Tsuda

Ken'ichi Natsui

Takanao Kurasawa

Yoshiaki Inui

Katsumi Kuroda

Youichi Oshita

Syunkichi Endo

Tasunori Ohno

Nobuya Sekimoto

Kouzi Suzuki

Tokio Goto

Yashuharu Seki

Masao Morita

Katuichi Kashimura

A power use circuit breaker includes an arc generating switching unit which adds an electrical resistance in a circuit during current interruption to attenuate a current to be interrupted, a vacuum bulb which is electrically connected in series with the arc generating switching unit and interrupts the attenuated current and a current conducting switching unit connected in parallel with the series circuit of the vacuum bulb and the arc generating switching unit. For current conduction the current conducting switching unit is closed after the vacuum bulb and the arc generating switching unit are closed, and for current interruption after opening the current conducting switching unit, the vacuum bulb and the arc generating switching unit are opened.

Power use circuit breaker and electrical circuit arrangement for electric power generation plant

According to the present invention there are provided a highly reliable electrode of high strength which undergoes little change even with the lapse of time, and a method for making the same, as well as a vacuum valve using such electrode and a vacuum circuit breaker using such vacuum valve. The vacuum circuit breaker has a fixed electrode and a movable electrode, each comprising an arc electrode, an arc electrode support member for supporting the arc electrode, and a coil electrode contiguous to the arc electrode support member, the arc electrode, the arc electrode support member and the coil electrode being formed as an integral structure by melting, not by bonding, particularly the arc electrode support member and the coil electrode being constituted by a Cu alloy containing 0.05-2.5% by weight of at least one of Cr, Ag, W, V and Zr.

Vacuum circuit breaker as well as vacuum valve and electric contact used

A puffer type gas-blast circuit breaker includes a guide section arranged at a coupler section between a shaft section of a puffer cylinder and a dielectric operating rod, for guiding both in the axis direction of a current interruption section and in the radial direction thereof, thereby to suppress or eliminate the occurrence of misalignment of center axis between movable components and fixed ones thus causing a gap to remain constant between a dielectric nozzle and a fixed arc contact. With such an arrangement, the gap between the nozzle and the contact can be kept uniform even when the pole-to-pole distance is increased with an increase in the high withstanding voltage of the breaker. This ensures that the surface-creeping electric field on the inner surface of the dielectric nozzle can be at a desired design value, thus enabling to provide a stable pole-to-pole insulation characteristic during current interruption operations.

Puffer type gas circuit breaker

A puffer type gas breaker is provided, in which high-temperature gas, heated by an electric arc produced immediately after a large current is broken, is quickly discharged to enhance inter-pole dielectric performance. A fixing portion for fixing an arc contact is provided in a cylindrical exhaust pipe for exhausting the high-temperature gas heated by an electric arc produced between poles immediately after a large current is broken. A rectifying member or members is provided in the fixing portion of the cylindrical exhaust pipe. An exhaust port or ports is formed in the fixing portion of the cylindrical exhaust pipe, and a shield is disposed around the outer periphery of the exhaust port or ports.

Puffer type gas breaker

Method forming an electric contact in a vacuum circuit breaker

A vacuum switch having a fixed side electrode unit and a movable side electrode unit mounted in a vacuum vessel. Each electrode unit includes an arc electrode, an arc electrode supporting member for supporting the arc electrode, a coil electrode and a conducting rod. Joining portions between the arc electrode and the arc electrode supporting member, the coil electrode and the conducting rod are integrally and directly formed metallurgically by solid phase diffusion using a hot isostatic process. A vacuum circuit breaker may be constructed incorporating the vacuum switch.

Vacuum circuit breaker with improved contact assembly

A compression gas puffer type circuit breaker has a magnetic body surrounding a conductor between a stationary arc contact and a main bus conductor. The magnetic body is protected from being exposed to heated puffer gas generated when a movable arc contact is separated from the stationary arc contact by disposing an insulator partition plate supporting the conductor at the downstream end of a cylindrical contact base carrying a main stationary contact and upstream of the magnetic body. Conductors are disposed around the magnetic body so as to increase flux linkage with the magnetic body when an arcing current flows through the conductor during a circuit breaking operation.

Compression gas puffer type circuit breaker

An apparatus for controlling a switching device provided for breaking or closing a power line connecting a power source to a load in an electric power system includes a switching timing control unit for controlling the timing to apply a breaking signal to said switching device in response to a breaking signal externally applied thereto so that the contacts of said switching device are opened during a period of time when the current flowing through said power line first reaches its peak value from a zero value and for controlling the timing of applying a closing signal to said switching device in response to a closing command preferably externally applied thereto so that the contacts of said switching device are closed when the voltage of said power source becomes a predetermined value depending upon whether said load is capacitive or inductive, and an operating unit for opening and closing said contacts of said switching device in response to said breaking and closing signals, respectively.

Apparatus for controlling opening and closing timings of a switching

Vacuum circuit breaker and electric contact

A switching mechanism for use e.g. in a circuit breaker of an underground electric substation has a movable rod which causes opening and closing of an electrical contact and a hydraulic operating system. The hydraulic operating system uses a hydraulic fluid which has a high flammability temperature or is incombustible. Thus, even if such fluid leaks from the hydraulic operating system, the risk of fire or explosion is minimized. The hydraulic operating system may have a sealed tank for the fluid, preferably with a variable volume expansion chamber. In a further development, the hydraulic operating system and possibly parts of the movable rod, is enclosed in a casing which is sealed and is filled with a gas which does not support combustion therein. Thus, the risk of fire or explosion is further reduced. The casing may have a variable volume expansion chamber.

Switch mechanism

An electrical power supply system includes an electrical power source system connected to a bus bar and a plurality of electric power transmission systems each connected via circuit breakers to the bus bar. The supply system has overvoltage suppression equipments each installed between the transmission system and the ground. The overvoltage suppression equipment includes a switching device and an impedance connected to the switching device. The switching device in a sound transmission system is closed when the circuit breaker operates in other faulty transmission system, thereby an overvoltage being occurred on the sound system is effectively suppressed.

Electrical power supply system

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. The cathode of the fifth diode and the anode of the sixth diode or the anode of one and the cathode of the other one of the last two diodes of the ladder circuit are connected together at a common point, which is selected to be the other terminal of the switch.

Solid-state switch

A gas isolated disconnecting switch is provided which performs a sufficient restriking surge suppressing function, induces no adverse effect on the operation of a circuit breaker disposed within the system and always enables the circuit breaker to surely interrupt a fault current. Under the closed condition of the gas isolated disconnecting switch, a main stationary member 6 engages with a main movable member 16 and an auxiliary movable member 17 with an auxiliary stationary member 8 respectively. Accordingly the portion of an auxiliary conductor 7 which passes through a cylindrical magnetic body 9 is short-circuited via the main stationary member 6 and the main movable member 16, and no influence is induced on the operation of the circuit breaker disposed in the system. During the opening operation of the disconnecting switch, the auxiliary movable member 17 disengages with a time delay. At this moment, the current flows through the portion of the auxiliary conductor 7 which passes through the cylindrical magnetic body 9 to thereby perform a sufficient restriking surge suppressing function.

Gas isolated disconnecting switch and gas isolated switching device

Growing community of inventors

Hitachi, Japan

Yukio Kurosawa