Hitachi, Ltd.

Yuzuru Kamata

Tokio Yamagiwa

Fumihiro Endo

Toshio Ishikawa

Jun Ozawa

Yasuro Hori

Masanori Tsukushi

Youichi Ohshita

Makoto Yano

Shigeo Shiono

Noriyuki Yaginuma

Minoru Kanoi

Katsuhiko Shiraishi

Ken'ichi Natsui

Rikizo Ishikawa

A transformer station includes a plurality of power transmission lines receiving electric power, a bus bar connected to the power transmission lines, a transformer connected to the bus bar to transform voltage of the electric power supplied from the bus bar, and breakers between one of the power transmission lines and the bus bar and between the transformer and the bus bar. The breakers are aligned along an imaginary line extending substantially parallel to the bus bar.

Transformer station and breaker apparatus

A gas insulated electrical apparatus comprises: a metal pipe in which an insulation gas is sealed; a conductor supported inside of the metal pipe by an insulation supporting member; and an insulation layer provided on the inner surface of the metal pipe. Strong dielectric material is mixed in the insulation layer so that its specific inductive capacity becomes ten or more.

Gas insulated apparatus with internal coated insulation layer of high

An electret capable of holding electric charges semi-permanently is used to attract conductive particles generated or intruded in a gas-insulated electric apparatus during assembly work including an operation test of movable parts thereof, thus improving the reliability of insulation characteristic of the apparatus.

Gas-insulated electrical apparatus with electret for captivating

A noise-reduction device for a stationary induction apparatus which device comprises a sound insulation panel attached to reinforcing channels provided at the periphery of a tank of the stationary induction apparatus so as to block noises emitted from the outer surface of the tank, a weighty body attached to the sound insulation panel for reducing vibrations of the sound insulation panel and a dynamic damper of which the natural frequency can be adjusted to be made equal to the vibration frequency of the weighty body so as to cancel the vibrations of the weighty body.

Noise-reduction device for stationary induction apparatus

A light source for forming an optical path extending across a closed vessel and a light receiving unit for receiving light from the light source are disposed outside the closed vessel. A portion to have its temperature measured as lies in the closed vessel is provided with a temperature detecting device which consists of a temperature sensor and a light interceptive plate. The temperature sensor is formed to be downwardly convex by sticking two members of different coefficients of thermal expansion one over the other (the member of the larger coefficient of thermal expansion being arranged over the member of the smaller coefficient of thermal expansion). The light interceptive plate is arranged over the member of the larger coefficient of thermal expansion. When the portion to have its temperature measured has reached a predetermined temperature, the temperature sensor inverts the downwardly convex state into an upwardly convex state. Owing to the inversion of the state of the temperature sensor, the light interceptive plate is turned into the optical path extending across the closed vessel, from outside the same and intercepts part of the light from the light source. Thus, the quantity of the light to be received by the light receiving unit changes, and the temperature of the portion is measured through a light quantity--temperature conversion.

Temperature measurement apparatus

A ceramic capacitor comprises a column-like ceramic element having end faces provided with electrodes, respectively. A disk-like reinforcing element is secured to at least one of the electrodes in close contact therewith. The thickness T and diameter D of the ceramic element are selected so that T/D.ltoreq.0.5 and D.sub.t /D.gtoreq.0.6 where D.sub.t represents the thickness of the reinforcing metal member. The dielectric breakdown field strength appearing upon application of a chopped-wave impulse voltage can be increased at least to the dielectric breakdown field strength appearing upon application of a full-wave impulse voltage.

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Hitachi, Japan

Yuzuru Kamata