Hitachi, Ltd.

Kastuichi Kashimura

Yukio Kurosawa

Osamu Koyanagi

Kenji Tsuchiya

Masanori Tsukushi

Isao Takahashi

Kunio Hirasawa

Goro Daimon

Yoshihito Asai

Kazuhiro Saito

Isao Nishida

Kogi Ishikawa

Eisaku Mizufune

Minori Satoh

Minori Sato

A puffer type gas-blast circuit breaker includes a guide section arranged at a coupler section between a shaft section of a puffer cylinder and a dielectric operating rod, for guiding both in the axis direction of a current interruption section and in the radial direction thereof, thereby to suppress or eliminate the occurrence of misalignment of center axis between movable components and fixed ones thus causing a gap to remain constant between a dielectric nozzle and a fixed arc contact. With such an arrangement, the gap between the nozzle and the contact can be kept uniform even when the pole-to-pole distance is increased with an increase in the high withstanding voltage of the breaker. This ensures that the surface-creeping electric field on the inner surface of the dielectric nozzle can be at a desired design value, thus enabling to provide a stable pole-to-pole insulation characteristic during current interruption operations.

Puffer type gas circuit breaker

The invention relates to a synthetic equivalent test circuit which can generate a 4-parameter transient recovery voltage TRV, for verifying a large current breaking performance of a power circuit breaker. A current source current is supplied to only a testing circuit breaker which is to be tested and an auxiliary circuit breaker. A small current with respect to the current source current is transmitted to the first and second auxiliary switches from a power source. When the small current form the current source or the resonance circuit flows, the first auxiliary switch is opened almost simultaneously with the auxiliary circuit breaker, the testing circuit breaker and operates so as to break the current at the time point of the final zero point of the current source current. Therefore, the connection of the voltage source circuit just before the final zero point of the current source current, that is, the current supply of the voltage source current and the breaking of a capacitor circuit current by the first auxiliary switch generates a 4-parameter TRV that can be accomplished easily.

Synthetic equivalent test circuit of circuit breaker

In a circuit breaker in which an interrupting device, a resistor device and a capacitor device are connected in parallel, a shield device is arranged to shield the interrupting device and the resistor device and comprises a first shield for shielding the stationary main contact and stationary resistor contact and a second shield for shielding the movable main contact and movable resistor contact. Each of the first shield and the second shield comprises a large shield portion and a small shield portion, and the small shield portions are arranged between the large shield portions. The small shield portion terminates in the vicinity of the top of the main contact and of the top of the resistor contact. The small shield portion comprises wide portions situated substantially in the direction of an axis joining centers of the main contact and resistor contact and narrow portions situated substantially in the direction perpendicular to the axis. The width of the narrow portions is smaller than the width of the wide portions, and at least a part of the capacitor device is arranged over the narrow portions. In the circuit breaker, since the capacitor device is arranged over the narrow portions, the space for arranging the capacitor device is larger than the conventional circuit breaker, the arrangement of the isoelectric liens is not disturbed or disordered locally in the vicinity of the top of the shield of the stationary main contact and in the vicinity of the movable main contact and high dielectric strength between the main contacts is obtained.

Circuit breaker

Growing community of inventors

Takahagi, Japan

Kastuichi Kashimura