Hitachi, Ltd.

Katsuichi Kashimura

Osamu Koyanagi

Masanori Tsukushi

Yukio Kurosawa

Kunio Hirasawa

Yoshihito Asai

Eisaku Mizufune

Yoshio Yoshioka

Goro Daimon

Kogi Ishikawa

Kenji Tsuchiya

Takashi Sato

Makoto Yano

Kenichi Natsui

Minori Sato

Ken'ichi Natsui

Yukio Korosawa

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 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

The present invention relates to a puffer type circuit breaker having a high voltage and large capacity, which is provided with an insulating nozzle for blowing a arc-extinguishing gas of high pressure generated by separating a movable contactor from a fixed contactor. The fixed contactor has a larger diameter portion formed on the base portion thereof and a smaller diameter portion formed at the tip end thereof, and the insulating portion has a first throat portion adjusted by the smaller diameter portion and a second throat portion located at the downstream side of the first throat portion and adjusted by the larger diameter portion, thereby allowing the gas inlet portion to be formed by the diameter difference between the first throat portion and the smaller diameter portion which is in such manner that the second throat portion is adjusted by the larger diameter portion. By virtue of these features, when the contactors are separated from each other, even if the arc-extinguishing gas of high pressure flows into the space between the first throat portion and the second throat portion, the rapid gas flow is not generated therein. Accordingly, since the arc-extinguishing gas is prevented from lowering the gas density on the tip of the fixed contactor, it is possible to improve the breaking ability of small capacitive current.

Puffer type circuit breaker

A grounded support tank type gas circuit breaker comprising a cylindrical tank maintained at ground potential and filled with an arc-extinguishing gas, and a breaking unit disposed within the tank with its central axis extending along the axis of the tank. In the circuit breaker, a capacitor unit is disposed within the tank in axially aligned relation with the breaking unit with its axis extending along an extension of the central axis of the breaking unit, so that the capacitor unit can be easily incorporated in the circuit breaker by merely increasing the axial length of the tank.

Grounded support tank type gas circuit breaker

An electromagnetic puffer type gas circuit breaker comprises two opposing puffer type gas circuit breaking units mounted on midway support means, actuating means for driving the circuit breaking units, an electromagnetic actuating unit drivingly coupled to the actuating means, and current transfer mechanism for transferring and applying the interrupting current to the electromagnetic actuating unit during a circuit breaking operation. The current transfer mechanism is located, in operative connection to the actuating means, at a point above the midway support means and in a spaced relation to the electromagnetic actuating unit. The contact surface area of the current-conducting path portion leading to the transfer mechanism is a fraction of that of another current-conducting path portion for the passage of most of the rated current. These features provide ease of inspection and replacement of the current transfer mechanism and reduces the operating force requirement of the breaker.

Electromagnetic puffer type gas circuit breaker

In a magnetic puffer type gas circuit breaker including an electromagnetic coil through which a current to be interrupted flows during the breaking operation, and an electromagnetic repulsive member which produces an electromagnetic repulsive force in cooperation with the electromagnetic coil and drives movable parts of a breaking portion of the apparatus, the electromagnetic repulsive member is so arranged that the electromagnetic neutral position of the electromagnetic repulsive member within the electromagnetic coil at the time when the breaking portion has been closed deviates on the closing side with respect to the electromagnetic center of the electromagnetic coil. Further, the characteristics of the electromagnetic repulsive forces between the electromagnetic coil and the electromagnetic repulsive member are so set that their absolute values become smaller on the closing side than on the breaking side with respect to the point at which the electromagnetic center of the electromagnetic coil and the electromagnetic neutral position of the electromagnetic repulsive member are coincident.

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Takahagi, Japan

Katsuichi Kashimura