Hitachi, Ltd.

Hitachi Industrial Equipment Systems Co., Ltd.

Takashi Shirone

Takashi Sato

Tomoaki Utsumi

Kenji Tsuchiya

Kazuhiro Satou

Masato Kobayashi

Ayumu Morita

Takashi Iga

Akira Nishimizu

Daisuke Sugai

Takahide Matsuo

Noriyuki Hayashi

Youichi Amako

Yoshito Uwano

Takafumi Hosono

Kaoru Endou

A switch unit includes a plurality of switches, which are linearly disposed. The movable electrode in one switch and the fixed electrode in another switch are electrically connected to each other.

Switch unit and switchgear

A switchgear includes an earthing and disconnecting switch which linearly moves and is switchable to a disconnecting and an earthing positions, a vacuum valve which performs closing and breaking of a current in a vacuum container producing vacuum inside, and a solid insulator with which the earthing and disconnecting switch and the vacuum valve are covered, therein the earthing and disconnecting switch and the vacuum valve are electrically connected, and closing and breaking of a current is performed in the vacuum valve.

Switchgear and method for operating switchgear

A main circuit switching unit and an isolator are accommodated in a vacuum container. A first conductor and a main circuit conductor are arranged to extend in and out of the vacuum container. A movable electrode of the main circuit switching unit is connected to the first conductor through a first flexible conductor, and a movable electrode of the isolator is connected to the main circuit conductor through a second flexible conductor. A shield is arranged around the first conductor and the main circuit conductor. Another shield is arranged around a connecting portion between the first flexible conductor and the movable electrode of the main circuit switching unit. A still another shield is arranged around the isolator. A further another shield is arranged around the second flexible conductor. These shields are secured to the vacuum container through insulating spacers. This arrangement instantly eliminates a dielectric breakdown phenomenon that occurs at electric field concentrated regions by the shields to prevent a dielectric breakdown caused by particulate foreign matters and thereby improve an insulation reliability of the devices.

Vacuum switchgear

A gas insulation transformer, in the tank of which transformer an apparatus including an iron core and a coil is received and a gas is filled as an insulating and cooling medium, is provided, wherein the iron core and coil are possessed with the loss characteristics equivalent to that of a high-efficient transformer and an inert gas, the global warming coefficient of which gas is rated 1 or below, is filled in the tank as an insulating and cooling medium.

Gas insulation transformer

An object of this invention is to provide a system for utilizing exhaust heat of a stationary induction apparatus in which highly-useful hot water, for example, of about 70.degree. C. can be provided without increasing an operating temperature of the stationary induction apparatus (e.g. a transformer) to such an extent as to adversely affect the lifetime of the stationary induction apparatus. The system of the present invention includes a heat pump 17 which uses, as a high-temperature heat source, a first stationary induction apparatus cooling system which includes a first water-cooled stationary induction apparatus 1, and a first cooling water circulation system 7, and exhaust heat utilization means 8. This heat pump also uses, as a low-temperature heat source, a second stationary induction apparatus cooling system which includes a second stationary induction apparatus 10, and a second cooling water circulation system 16. There is further provided a refrigerator 26 which uses the second stationary induction apparatus cooling system as a high-temperature heat source, and also uses warm water 22 in a cable-cooling cold/warm water tank 21 as a low-temperature heat source.

System for utilizing exhaust heat of stationary induction apparatus

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Hitachi, Japan

Takashi Shirone