Hitachi, Ltd.

Osamu Koyanagi

Masanori Tsukushi

Yukio Kurosawa

Yasuharu Seki

Katsuichi Kashimura

Yoshihito Asai

Eisaku Mizufune

Goro Daimon

Kogi Ishikawa

Kenji Tsuchiya

Youichi Ohshita

Kunio Hirasawa

Yoshio Yoshioka

Isao Nishida

Ken-ichi Natsui

Kastuichi Kashimura

Minori Sato

Takashi Sato

Makoto Hirose

Tadashi Sato

Junzo Kida

Akira Hashimoto

Makoto Yano

Kenichi Natsui

Kazuhiro Saito

Tomoyuki Andou

Ken'ichi Natsui

Tokio Goto

Yashuharu Seki

Katuichi Kashimura

Yukio Korosawa

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.

Gas-insulated switchgear

The steep initial rate of rise of the transient recovery voltage across the poles of a circuit breaker just after a fault current break is decreased. The breaking performance in the case of a short-circuit fault to ground taking place in an electrical power transmission system at relatively as near a place as several kilometers apart from the circuit breaker, that is a short-line-fault is improved by a saturable reactor having a capacitor connected in parallel therewith to the circuit breaker in series. As a result, as the saturable reactor changes from the magnetically saturated state to the unsaturated state just before the zero point of the fault current, the self-inductance of the saturable reactor gradually increases and an LC resonance is produced between the self-inductance of the saturable reactor and the capacitor connected to the saturable reactor in parallel. Therefore, the peak value and the time period of the current flowing from the saturable reactor can be controlled to control the initial rate of rise of the transient recovery voltage.

Method of controlling transient recovery voltage and gas insulation

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

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

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

A circuit breaker with a parallel resistor which fulfills with a simple structure incompatible requirements for a resistance circuit making contact with regard to maintenance of the dielectric strength and prearcing characteristic between electrodes. A resistance circuit making contact 2 and a resistance circuit breaking contact 3 are electrically connected in parallel, one end of the parallel circuit is connected to one end of a common resistor and the other end of the parallel circuit and the other end of the resistor are connected to the respective ends of a main contact 1. After the opening of the resistance circuit making contact 2 the resistance circuit breaking contact 3 is still closed.

Circuit breaker with parallel resistor

A gas circuit breaker comprising a pair of contactors separable from each other, an insulating nozzle surrounding the contact portions of the contactors so as to guide a flow of gas, and a puffer chamber for compressing the gas in conjunction with a separating operation of the contact portions so as to supply the gas, guided by the insulating nozzle from the puffer chamber through exhaust passage passing through a hollow portion of the movable one of the contactors located within the insulating nozzle. The exhaust passages are formed between the puffer chamber and one of the contactors. An exhaust gas guide opens through an end of an exhaust gas guide between the contact closing time and the time about which a movable contactor and a fixed contactor are to be separated at an initial stage, close during the initial stage of the separating operation and open afterward exhaust ports formed at ends of the exhaust passages located on a downstream side of the gas flow, there by making it possible to reduce the flow resistance to the gas flow used for arc extinguishment in cooperation with an arc-extinguishing gas flow passing through a throat portion of the insulating nozzle, to reduce a force required for operation and to reduce the size of the gas circuit breaker.

Gas circuit breaker

A gas circuit breaker comprising: a pair of contactors having separable contact portions, a nozzle arranged to surround the contact portions of the contactors so as to guide a flow of a gas; a puffer chamber for compressing the gas in response to a circuit breaking action and for supplying the compressed gas into the nozzle; and an exhaust passage in one of the contactors which is adjacent to the nozzle, the gas supplied from the puffer chamber being discharged through the exhaust passage. The exhaust passage includes a first passage formed in the one of the contactors so as to extend in the axial direction thereof and second passages communicating with and branching from the first passage and extending radially with respect to the axis of the one of the contactors at positions between gas discharging holes which are provided in the puffer chamber at a predetermined circumferential spacing. A projection formed of an arc-resistant member is provided on the branch connection between the first passage and the second passages.

A gas circuit breaker having a main fixed element and a main movable element capable of contacting and moving apart from each other, a fixed contact provided on the main fixed element side, a movable contact provided on the main movable element side and capable of contacting and moving apart form the fixed contact, an insulation nozzle provided on the main movable element side to surround the contacts, a hollow nozzle provided inside the movable contact, a cylinder, a puffer cylinder and a fixed piston provided on the main movable element. The insulating nozzle serves to compress a gas in a puffer chamber defined by the puffer cylinder and a fixed piston and to guide the gas to the gap between the contacts disconnected. The circuit breaker also has an opening formed in a side surface of the cylinder to discharge the gas from the insulation nozzle, a gas flow passage formed to provide a passage between the hollow nozzle and the opening, and an exhaust guide provided outside the main movable element to close the opening. The exhaust guide is divided into a plurality of guide members connected by releasable fixing device. One of these guide members can be moved relative to the others when the fixing device is released.

A gas circuit breaker comprising a pair of contactors contact portions of which are separable relatively from each other, an insulating nozzle of an electrically insulating material surrounding the contact portions of said contactors so as to guide a flow of gas, and a puffer chamber for compressing the gas in conjunction with a separating operation of the contact portions so as to supply it under guidance of the insulating nozzle, the gas from the puffer chamber being exhausted through exhaust passages passing through a hollow portion of the one contactor located within the insulating nozzle, wherein the exhaust passages are formed between the puffer chamber and the one contactor, and the gas circuit breaker further comprises block means serving to close during an initial stage of the separating operation and open afterward exhaust ports formed at ends of the exhaust passages located on the downstream side of the gas flow. This makes it possible to reduce the flow resistance to the gas flow used for arc extinguishment in cooperation with an arc-extinguishing gas flow passing through a throat portion of the insulating nozzle as well as to reduce a force required for operation.

A puffer type gas circuit breaker having at least one pair of a stationary contact and a movable contact capable of being separated from each other, a pressure producing section including a puffer cylinder and a puffer piston. The puffer cylinder is connected to the movable contact and serves to compress an arc extinguishing gas blown to an arc generated between the contacts at the time of current breaking. The breaker also has a cover surrounding the movable contact, an insulated nozzle extending from the puffer cylinder and surrounding the cover and the stationary contact to form a flow passage through which the compressed gas is supplied from the puffer cylinder to the generated arc, and a flow straightening member provided in said flow passage. The flow straightening member extends from the puffer cylinder and is mounted on the cover, and the flow passage has an expanded section having a gas flow sectional area larger than that of the section of the flow passage upstream of the expanded section.

Puffer type gas circuit breaker, contact cover and insulated nozzle of

A gas circuit breaker includes a pair of separable contact portions, a nozzle of an electrically insulating material surrounding the contact portions to guide a flow of gas, and a buffer chamber for compressing the gas upon a separating operation of the contact portions so as to supply the gas under the guidance of the insulating nozzle. The gas from the puffer chamber is exhausted through exhaust passages passing through a hollow portion of a movable one of the contactors. The exhaust passages are formed between the puffer chamber and the movable contactor. A blocking arrangement, during initial stage of the separating operation, closes the exhaust ports of the exhaust passages and subsequently opens the exhaust ports located on a downstream side of the gas flow. The blocking arrangement, of an electrically insulating material, is divided along an axial direction of the gas circuit breaker. Electrical insulating material of the blocking arrangement is fastened by springs from the exterior of the circuit breaker to reduce unnecessary gas flow from the puffer chamber through the blocking arrangement.

In a circuit breaker in which an interrupting device, a resistor device and a capacitor device are connected in parallel, a shield device is arranged to shield the interrupting device and the resistor device and comprises a first shield for shielding the stationary main contact and stationary resistor contact and a second shield for shielding the movable main contact and movable resistor contact. Each of the first shield and the second shield comprises a large shield portion and a small shield portion, and the small shield portions are arranged between the large shield portions. The small shield portion terminates in the vicinity of the top of the main contact and of the top of the resistor contact. The small shield portion comprises wide portions situated substantially in the direction of an axis joining centers of the main contact and resistor contact and narrow portions situated substantially in the direction perpendicular to the axis. The width of the narrow portions is smaller than the width of the wide portions, and at least a part of the capacitor device is arranged over the narrow portions. In the circuit breaker, since the capacitor device is arranged over the narrow portions, the space for arranging the capacitor device is larger than the conventional circuit breaker, the arrangement of the isoelectric liens is not disturbed or disordered locally in the vicinity of the top of the shield of the stationary main contact and in the vicinity of the movable main contact and high dielectric strength between the main contacts is obtained.

Circuit breaker

Breaker units (3, 4) of three-phases are enclosed in a common container (25). The three-phase breaker units and lead conductors (27a, 28a) connected to both ends of the breaker units are arranged on imaginary straight lines that are in parallel each other nearly passing through vertexes of an equilateral triangle. A common operation unit (7) for driving the three-phase breaker units is accommodated outside the container (25) and juxtaposed at a position opposed to one side (28b-28c) of the equilateral triangle. A zero-phase sequence current transformer (ZCT) is provided surrounding the lead conductors of three phases outside the container.

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Hitachi, Japan

Osamu Koyanagi