Mitsubishi Denki Kabushiki Kaisha

The Kansai Electric Power Co., Inc.

Electric Power Development Co., Ltd.

Shikoku Electric Power Co., Inc.

Etsuo Nitta

Hiroki Ito

Kenji Kamei

Takashi Moriyama

Suenobu Hamano

Masayuki Hatano

Naoaki Takeji

Kazuhiko Arai

Hiroyuki Sasao

Minoru Kimura

Takashi Yonezawa

Koji Yamaji

Takateru Hashimoto

Koji Takahata

A DC circuit breaking device is provided for interrupting the transmission of direct currents to an electric power system by making external changes to an arc generated upon contacting or separation of contacts 11 and 12 in order to rapidly extend and vibrate arc currents. In a self-excited commuting DC circuit breaking device, coils 41 and 42 opposed to a fixed and a movable contact 11 and 12, respectively, are disposed around the outer circumferences of the contacts 11 and 12, and currents flowing through a commutation circuit or the contacts 11 and 12 are allowed to flow through the opposed coils 41 and 42 so as to apply magnetic fields to the neighborhood of an arc. This constitution provides the DC circuit breaking device with high performance that it can rapidly extend and vibrate arc currents to thereby interrupt direct currents.

DC circuit breaking device

An objective of this invention is to provide a DC circuit breaking device having functions for transmitting direct currents to an electric power system and interrupting direct currents to the electric power system under abnormal conditions such as grounding and short-circuits, where the DC circuit breaking device can minimize the capacity of a condenser for the commuting circuit while rapidly changing the arc voltage to cause arc currents to be quickly extended and vibrated in order to interrupt direct currents in a short arc time. This DC circuit breaking device includes a main DC circuit breaker for interrupting the transmission of direct currents to an electric power system and a DC circuit breaker that is connected in series to the main DC circuit breaker and which is smaller than the main DC circuit breaker. The circuit breaking device also includes a commutation circuit that is connected in parallel to the DC circuit breaker and the small DC circuit breaker which are connected together in series and which is constituted by a reactor and a condenser. The circuit breaking device also includes a surge absorber for absorbing a surged voltage applied to for the condenser.

Circuit breaking device

A small-sized arrangement for a DC circuit breaker with a reactor and a capacitor connected in series is provided which includes a DC circuit breaker, a parallel impedance means with a suitably determined inductance and a suitable capacitance less in value than the inductance, and an energy-absorbing element. The parallel impedance means has a parallel reactor of a carefully selected inductance and a parallel capacitor of a smaller capacitance value. Determining the inductance and capacitance values of the parallel reactors and parallel capacitors employed in the parallel impedance means to satisfy a certain condition defined by specific formulas can cause the DC circuit breaker to take full advantage of the inherent performance thereof while allowing the interruption time to remain minimized, thereby achieving enhanced interruption performance. Since the capacitance of the parallel capacitor is rendered relatively smaller, the device can be small in size and low in cost.

Arrangement for gas circuit breaker with reactor and capacitor connected

Growing community of inventors

Tokyo, Japan

Etsuo Nitta