Hitachi, Ltd.

Naoki Amano

Tohru Tsubaki

Toru Tsubaki

Hitoshi Kayaba

Takeshi Takahashi

Koji Sasaki

Tokio Yamagiwa

Seizo Nakano

Satoshi Miwada

Takehiro Kikuchi

Koji Kurokawa

Yoriyuki Aiko

Naoyuki Yamamoto

Yukio Kamura

Yoichiro Koizumi

Kyuzi Yaginuma

Sigeru Fujiya

A puffer type gas-insulated circuit breaker is adapted to, when its movable electrode separates from a stationary electrode, enable an insulating gas blow toward an occurring arc to extinguish the same. An insulated nozzle is provided to direct the gas toward the arc and forms a gas passage in cooperation with an insulating cover which covers the movable electrode. The insulated cover is formed of an insulating material which contains a filler for preventing energy lines of the arc from entering the cover. Furthermore, the insulated cover has a specific inductive capacity greater than a specific inductive capacity of the insulated nozzle so as to reduce the electric field strength at the front end of the movable electrode.

Puffer type gas-insulated circuit breaker

A gas-insulated switching device includes a bus bar-connecting conductor, within a cylindrical container, which connects one end of a circuit breaker portion, disposed wihtin the container, to a main bus bar mounted on the outer side of the container. The bus bar-connecting conductor is inclined relative to the axis of the container in such a manner that one end of the bus bar-connecting conductor connected to the main bus bar is situated closer to the other end of the breaker portion than to the one end of the breaker portion, and radially more outwardly of the breaker portion than the other end of the bus bar-connecting conductor connected to the one end of the breaker portion. As the bus bar-connecting conductor is inclined in the above manner, the device can be of a compact size without possibility of affecting the insulation between the bus bar-connecting conductor and the other end of the breaker portion by the voltage applied therebetween in the open or circuit-breaking state of the breaker portion.

Gas-insulated switching device

A gas-insulated switchgear apparatus including a three-phase circuit breaker, a three-phase disconnecting switch and a cable head, with the disconnecting switch and the cable head being accommodated in a cable head housing. To minimize the size of the disconnecting switch, movable insulators, connected to movable conductors, and stationary insulators, supporting connecting conductors, are arranged so that the movable and stationary insulators form triangles disposed substantially in the same plane with the respective triangles being inverted in relation to each other.

Gas-insulated switchgear apparatus

A gas-insulated switchgear apparatus is disclosed, in which a bus bar-dividing unit is interposed through main bus bars between feeder units connected to a transmission line or a transformer. The main bus bars are arranged in substantially the same axis. A circuit breaker of vertical type making up the bus bar-dividing unit includes an upper electric path and a lower electric path. The lower electric path is connected to one of the main bus bars while the upper electric path is connected to the other main bus bar at a position displaced axially of the main bus bar opposed to the circuit breaker of vertical type. This construction with the circuit breakers of vertical type arranged on the same axis facilitates maintenance and inspection.

A gas insulated switchgear equipment in which three circuit breakers are electrically connected in series between two main bus bars. The two main buses are parallelly mounted on a fixing base. The three circuit breakers are arranged on one side of the main buses and aligned in the axial direction of the main buses. Connecting buses for electrically connecting the circuit breakers are provided on one side of the circuit breakers where the main bus bars are also disposed. Thus, the circuit breakers are accessible from the other side thereof for their maintenance and inspection and the equipment mounting area can be minimized because the main buses are disposed in parallel.

Gas insulated switchgear equipment

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Hitachi, Japan

Naoki Amano