Hitachi, Ltd.

Manabu Takamoto

Masato Suzuki

Toyokazu Tanaka

Satoshi Miwada

Hideo Kawamoto

Masatomo Ohno

Masahiro Shimokawa

Sadao Waizumi

Noriyuki Tetsu

Shinji Seto

Tokio Yamagiwa

Kunio Hirasawa

Hirohiko Yatsuzuka

Hitoshi Yamada

Naoyuki Yamamoto

Hiromichi Hokuto

Kenji Annou

Kouichi Koyama

Yoshikatsu Enokida

Kenji Iwabuchi

Masahiro Yaegashi

Nobuyuki Kakuda

Noaki Kawamura

A fluid pressure operating apparatus, comprising: a fluid pressure cylinder for opening and/or closing a contact; control valves for use of open operation and/or closed-circuit, for bringing the fluid pressure cylinders into an opened-circuit operation and a closed-circuit operation; and solenoids, each being provided in each of those control valves. Each of those solenoids has a plunger therein. An operation initiating time of the control valves for use of open (operation) differs from that of the control valves for use of close (operation), when operating to open circuit and when operating to close circuit.

Fluid pressure operating apparatus for circuit breaker

A current transformer fixing device comprises a current transformer cylinder surrounding the periphery of a central conductor to be connected to an electric power line, a cylindrical container surrounding the outer peripheral side of a current transformer arranged on the outer peripheral side of the current transformer mounting cylinder and containing the current transformer, a transformer mounting plate connecting the bottom side of the current transformer mounting cylinder and the bottom side of the cylindrical container to each other and restricting axial movement of the current transformer, a sealing flange connected to the upper end of the cylindrical container with a gap between the sealing flange and the upper end of the current transformer mounting cylinder, and fixing bolts fastened to the sealing flange in an axial direction of the conductor and restricting axial movement of the current transformer.

Fixing device of current transformer

The gas-blasted circuit-breaker includes a movable arc contact, a fixed arc contact opposing the movable arc contact, an insulating nozzle, a puffer cylinder, a hollow conductor, an insulating rod connected to the puffer cylinder, and a fixed piston fitted inside the puffer cylinder. An insulating gas is ejected to a space between the puffer cylinder and the fixed piston by driving the insulating rod and is sprayed to an arc generated upon interruption of a current. The hollow conductor is in a cylindrical shape having a cross section parallel to the axis thereof. The cross section is smaller in diameter on the downstream side of a flow of insulating gas. The hollow conductor has a closed end on the downstream side of the flow of insulating gas and has a cylindrical barrel portion provided with a plurality of opening. With this configuration, this circuit-breaker ensures an operation of adjusting the flow of a heat gas, cooling of the heat gas and insulating performance for the fixed conductor to which the heat gas is sprayed.

Gas-blast circuit-breaker

A gas-insulated electrical apparatus includes tanks into each of which insulation gas is sealed, including bus-bars, bus-bar disconnectors connected to the bus-bars, circuit breakers connected to the bus-bar disconnectors, and line disconnectors connected to the circuit breakers, each line disconnector being further connected to a transmission or a transformer; wherein each bus-bar disconnector and each line disconnector include a respective pair of a fixed-contact and a moving-contact, the fixed-contact and the moving-contact being concave and convex, respectively, and each of the moving-contacts in the bus-bar disconnector and the line disconnector is located at the side of a corresponding circuit breaker between the bus-bar disconnector and the line disconnector, a contact-parting speed in the line connector being lower than that in the bus-bar disconnector.

Gas-insulated electrical apparatus

A circuit breaker includes a tank grounded and filled with an insulating gas, a first electrical series-connected section having a main conductor and a main breaking section, and a second electrical series-connected section having a resistor and an advance closing contact device. The first electrical series-connected section is coupled electrically in parallel to the second electrical series-connected section. The fixed contact side of the main breaking section is supported by an insulating cylinder and the fixed contact side of the advance closing contact device is supported by an insulating plate from the fixed contact side of the main breaking section. A breaking unit, chiefly composed of the main breaking section and the advance closing contact device, is supported by insulating cylinders. A resistor unit is supported by an insulating cylinder. The assembly of each of the units can be performed completely outside the tank, thereby eliminating the need for performing any adjustment type of work within the tank.

Gas insulated high voltage circuit breaker including tulip contact

A gas circuit breaker having a resistance circuit breaking portion connected in parallel with a main circuit breaking portion includes a main circuit breaking portion actuating mechanism and a resistance circuit breaking portion actuating mechanism. The resistance circuit breaking portion actuating mechanism is provided with a first delaying mechanism mechanically coupled to the main circuit breaking portion actuating mechanism, and a second delaying mechanism, independent from the first delaying mechanism, which is operated by an electrical command signal relating to either a making or an interrupting electrical signal to the main circuit breaking portion actuating mechanism. The otherwise possible thermal break-down of a resistor connected in series with the resistance circuit breaking portion is prevented.

Gas insulated switchgear insertion resistor and main contacts operating

A high voltage power receiving and transforming apparatus for consumer demands receiving power from two lines and supplying the power to respective transformers through instrument potential and current transformers. First circuit breakers at a primary side of the transformers, are arranged at both sides of the instrument potential and current transformers, second circuit breakers, at a receiving side, are arranged at both sides of said first circuit breakers. The circuit breakers and receiving portion connecting portion to the transformers, and the instrument potential and current transformer are connected by a duct line connection portion at a backside of the circuit breakers.

Receiving and transforming apparatus

A power receiving and transforming system comprising a gas insulated switchgear, with transformers being disposed adjacent the gas insulated switchgear and metal enclosed switchgear sections disposed on opposite sides of the transformers with respect to the gas insulated switchgear. The metal enclosed switchgear sections have metal enclosed switchgear units juxtaposed in a direction in which the gas insulated switchgear and the transformers are juxtaposed. The metal enclosed sections are located opposite to each other in a direction perpendicular to the direction of the juxtaposition. Therefore, the metal enclosed switchgear sections can be arranged so as to have a width equal to a width of the gas insulated switchgear and the width will not change even if the number of feeders in the metal enclosed switchgear sections is increased thereby enabling the entire power receiving and transforming system to be regularly installed at a site.

Customer's power receiving and transforming system

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Hitachi, Japan

Manabu Takamoto