Mitsubishi Denki Kabushiki Kaisha

Mikio Hidaka

Toshiaki Yoshizumi

Haruhiko Kohyama

Yoshiki Hirano

Hiroki Ito

Hiroyuki Sasao

Katsuhiko Horinouchi

Nobuya Nakajima

Suenobu Hamano

A synchronous switching apparatus for detecting a source voltage of each phase to close each phase at an electrical phase angle predetermined for each phase, including switching devices provided one for each phase for opening and closing an impedance load, switching devices for closing and opening the switching devices for each phase, measuring transformers for measuring source voltages of the respective phases and phase-to-phase voltages, and phase control devices each for issuing a command for energizing the impedance load at an electrical phase angle in a range predetermined for each phase, when detecting a zero point of a source voltage of each phase or a zero point of each phase-to-phase voltage.

Synchronous switching apparatus for use with a multiple phase power system

A phase control switching system for controlling opening and closing timings of a power switching device to suppress the occurrence of an exciting rush current or a make-and-break surge voltage which is severe to system equipment such as a transformer, a reactor and a capacitor bank, or for controlling an arcing time of a circuit breaker to put the circuit breaker into operation for the arcing time leading to no-re-ignition or for the optimal breaking time. In the phase control switching system, a current measuring section or a current gradient measuring section is provided to measure a current value or a current gradient value of a current to be broken or introduced, and a reference phase detecting section estimates a current zero point of a current waveform on the basis of the measurements. Subsequently, a control section, upon receipt of an opening/closing command, an opening phase control operation using an arbitrary time point after the current waveform estimation as a reference.

Phase control switching system

A switch for use in electric power includes a fixed contact, a moving contact performing a switching operation with respect to the fixed contact, a cylinder working with the moving contact, a piston slidably provided in the cylinder, a buffer chamber which is surrounded by the cylinder and the piston, and is filled with an arc-extinguishing gas, and a second insulating nozzle mounted to an end of the cylinder on the side of the fixed contact, wherein the arc-extinguishing gas in the buffer chamber is sprayed through the nozzle on an arc generating between the fixed contact and the moving contact at an opening time of the moving contact.

Switch

In a double-break type circuit breaker having resistor contacts which are to be connected in parallel with main contacts in not only closing operation but also breaking operation, the resistor contacts are opened by a force due to loading of elastic members in the breaking operation and the elastic members are loaded for storing the driving force In the closing operation.

Circuit breaker and driving mechanism thereof

In a stationary contact unit of a gas circuit breaker, an arc-quenching cylinder for passing an arc-quenching insulation gas is formed in a substantially semicircular shape, and the stationary contact unit is supported by an insulation frame which is disposed beneath the dent part of the semicircular portion of the arc-quenching cylinder. The insulation frame is prevented from the degradation of dielectric strength between the stationary contact unit and a grounded tank, and the size of the gas circuit breaker is decreased.

Gas circuit breaker

In a closing operation of a circuit breaker with resistor contact, a resister contact is closed prior to closing of a main contact by the same first hydraulic operation system. In opening operation, the resistor contact is driven by a second hydraulic operation system used to close the main contact after operating the main contact by the first hydraulic operation system. Opening timing of the resistor contact is controlled by a mechanical interlock mechanism or hydraulic control circuit.

Circuit breaker

A double-break type circuit breaker includes two resistor contacts which are to be connected in parallel with respectively two main contacts when the main contacts are closed. An engagement mechanism is provided for linking the main contacts operated by a first hydraulic operation apparatus and the resistor contacts operated by a second hydraulic operation apparatus.

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Amagasaki, Japan

Mikio Hidaka