Mitsubishi Denki Kabushiki Kaisha

The Kansai Electric Power Co., Inc.

Electric Power Development Co., Ltd.

Shikoku Electric Power Co., Inc.

Hiroyuki Sasao

Kenichi Koyama

Yukimori Kishida

Hiroyuki Akita

Toshie Takeuchi

Yoshihiro Ueda

Suenobu Hamano

Akihiko Iwata

Akihiro Suzuki

Hajimu Yoshiyasu

Mitsuru Tsukima

Toshiyuki Kikunaga

Soichiro Okuda

Toshimasa Maruyama

Toyomi Ooshige

Hiroshi Yamamoto

Toshiyuki Yoshizawa

Mitsugu Takahashi

Kazuhiko Kagawa

Chie Takahashi

Yuichi Yamaji

Kazuhiko Nishimiya

Eiji Moritoh

Hiroki Ito

Kenji Kamei

Katsuhiko Horinouchi

Takashi Moriyama

Yuichi Wada

Haruhiko Kohyama

Minoru Kimura

Masakazu Fukada

Hideaki Toya

Hiroshi Hasegawa

Mikio Hidaka

Kazuhiko Arai

Takafumi Nishioka

Yoshiki Hirano

Takashi Yonezawa

Masayuki Hatano

Sataro Yamaguchi

Naoaki Takeji

Etsuo Nitta

Kazuo Ikeda

Yutaka Murai

Tatsuya Hayshi

Mitsugu Takahasi

Takateru Hashimoto

Suichiro Okuda

Hirosi Hasegawa

Yoichi Ueno

Tosimasa Maruyama

Tokio Nakashima

Voltage compensating circuits are connected serially to a power system, including capacitors each having different charging voltages (in relationship of approximately 2(K=0, 1, 2, . . . ) times the smallest charging voltage value). The voltage compensating circuits convert DC voltages in the capacitors into AC voltages and output the AC voltages, respectively. The voltages of the capacitors are detected as detected values Vto VThe detected values Vto Vare used as bit signals for a reference value to check a voltage dip amount of the power system with the reference value and to convert the voltage dip amount into a binary signal. A combination is selected from the voltage compensating circuits in accordance with the binary signal so that the sum of output voltages of the selected voltage compensating circuits compensates the voltage dip of the power system.

Voltage fluctuation compensating apparatus

Voltage compensation circuits connect DC voltages accumulated in capacitors having respectively different charging voltageswhich are 2(where K=0, 1, 2, . . . ) times the minimum voltage into AC voltages. The voltage compensation circuits are connected in series to an electric power system in series. When the voltage dip occurs in an electric power system, a combination of voltage compensation circuits is selected from the voltage compensation circuits. The sum of the output voltage compensates the voltage dip. During normal operation, a high speed mechanical short circuit switch by-passes the voltage compensation circuits to reduce power loss.

Voltage compensating circuits are connected serially to a power system, including capacitors each having different charging voltages (in relationship of approximately 2 (K&equals;0, 1, 2, . . . ) times the smallest charging voltage value). The voltage compensating circuits convert DC voltages in the capacitors into AC voltages and output the AC voltages, respectively. The voltages of the capacitors are detected as detected values V to V . The detected values V to V are used as bit signals for a reference value to check a voltage dip amount of the power system with the reference value and to convert the voltage dip amount into a binary signal. A combination is selected from the voltage compensating circuits in accordance with the binary signal so that the sum of output voltages of the selected voltage compensating circuits compensates the voltage dip of the power system.

A switching apparatus for multiphase electric power includes switching units corresponding to different phases. Each switching unit includes an operating mechanism having a movable coil disposed between two fixed coils, and a switch portion having a movable contact operatively connected to the movable coil. A separate power supply may be provided for each switching unit to permit individual control of the different phases.

Switching apparatus

A switching device includes a pair of fixed coils and a pair of movable coils, with one pair being disposed between the other pair. Two of the coils may be connected back to back on opposite sides of a support plate to increase the stiffness of the coils and reduce damage due to impact between the fixed and movable coils. The coils include two sets of coils, each set including one of the fixed coils and one of the movable coils. The coil sets can be driven simultaneously or at different times to effect contact opening and closing.

A switching device includes a movable coil which is reinforced by a stiffener to increase the resistance of the movable coil to bending moments. The stiffener may include a nonmagnetic case which surrounds the movable coil. Alternatively or in addition, it may include a resin or other material encapsulating the movable coil.

Switching device

An electromagnetic repulsion drive switching device in which a contact-closing coil and a contact-opening coil are arranged to confront a conductive repulsive member, and in which a drive current is fed to a selected one of the individual coils from a capacitor charged to a predetermined charge voltage by a charging power source. A stationary contact and a movable contact are brought into and out of contact by a repulsion electromagnetic force generated between the coils and the repulsion member. A voltage control controls the output voltage of the charging power source so that the peak value of the drive current may fall within a range with respect to a temperature change of the capacitor. As a result, even if the working temperature of the capacitor changes, the drive current of the contact-closing coil and the contact-opening coil falls within a desired range.

Electromagnetic repulsion driven switch

A switching assembly includes a switch portion having a fixed electrode and a movable electrode which are separable, a movable portion secured between a movable shaft connected to the movable electrode and a movable coil by a magnetic body, and a fixed portion having a magnetic body disposed radially inside a fixed coil disposed opposite the movable portion, thereby enabling intensification and swift establishment of magnetic fields generated between the coils.

Switching assembly

In a switchgear, by using a spring with a varying spring constant from closing to electrode opening as a loading spring, spring load in the opened electrode state is made smaller than a spring load in the closed electrode state to decrease the energy required from electrode closing up to electrode opening. Moreover, by using a spring in which a load in the opposite direction to a load in the closed electrode state works in the opened electrode state, the opened electrode state can be held securely.

Switchgear

A switching apparatus includes a switch, a movable coil, stationary coil members, and a direction-of-conduction setter comprising diodes. The switch has a stationary electrode. The movable coil is fixedly mounted on a movable shaft coupled to the movable electrode. The stationary coil members are opposed to the movable coil. The power supply supplies an excitation current to the coils. The direction-of-conduction setter sets the direction of conduction, in which the excitation current flows from the power supply into the coils, so that the coils will electromagnetically react on each other. This arrangement provides highly efficient electromagnetic driving. Moreover, an opening power supply or closing power supply is required to have only a small capacity.

A fast changeover from one power system to another in the event of an irregularity in the power source system substantially reduces operating costs by minimizing a power loss in switches during conduction, dispenses with a cooling device for cooling a thyristor switch, and implements the thyristor switch in a compact and low-cost design. The power supply system for a load includes one switching apparatus for connecting a load to one power source system, and another switching apparatus for connecting the load to another power source system. Each of the switching apparatus includes a pair of thyristors connected in anti-parallel and a mechanical switch connected in parallel with the thyristor pair. The thyristor pairs and the mechanical switches are controlled so that the mechanical switches conduct a load current when the load is supplied with power from the one power source system in a steady power supply state. The thyristor switches conduct the load current during a power source changeover time within which the load is disconnected from one power source system and connected to the other power source system, and do not conduct the load current during the steady power supply state.

Electric power supply system for load

A switching device has a control section to transfer a gate control signal which switches plural thyristors from an ON state to an OFF state after a parallel switch is open and an opening degree of the parallel switch is met where no arc discharge is generated at a contact point in the parallel switch.

Switching device with parallel switch

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

A rectifying saturable reactor generates a magnetic force in a magnetic iron core in response to a current that flows through an electronic circuit. The saturable reactor makes use of saturable magnetic flux in view of a hysteresis loop of a magnetic material for rectification and selects the saturated magnetic flux to be greater than an integrated value of a voltage applied to the rectifier in the rectifying circuit. In order to improve a rectifying performance, a no cut and one turn structure or an equivalent is introduced into a magnetic core for providing a hysteresis loop that varies as much as possible in magnetic induction.

Rectifying saturable reactor

Growing community of inventors

Tokyo, Japan

Hiroyuki Sasao