Patent application number | Description | Published |
20080269952 | CONTROLLED SWITCHING DEVICE - A target-closing phase-map generating section generates in advance a target closing phase map in consideration of a pre-arc characteristic and variations of a mechanical action of a breaker, and amplitude fluctuations of the load voltage. A target-closing time calculating section calculates a target closing time string from frequencies and phases of the power source voltage and the load voltage, respectively, of the breaker referring to the target closing phase map. A closing control section, when a close command | 10-30-2008 |
20090134862 | Transformer Operation Control Apparatus and Method for Suppressing Magnetizing Inrush Current - A control portion | 05-28-2009 |
20100013470 | RESIDUAL MAGNETIC FLUX DETERMINING APPARATUS - A residual magnetic flux measurement apparatus measures residual magnetic fluxes by using a transformer-voltage measurement means for measuring transformer voltages; a voltage delay means for delaying the measured signals; a DC-voltage-component calculation means for calculating DC voltage components from the latest transformer-voltage signals for a predetermined time period based on calculation-control signals; a voltage integration means for calculating voltage-integration signals by performing voltage integration of signals obtained after separating the DC voltage components from present transformer-voltage signals; a magnetic-flux DC-component calculation means for calculating magnetic-flux DC-components from the latest voltage-integration signals for a predetermined time period based on the calculation-control signals; a magnetic flux calculation means for obtaining magnetic flux signals in which the magnetic-flux DC-components are separated from present voltage-integration signals; and a control means for obtaining residual magnetic fluxes based on contact signals, an interruption mode, the transformer-voltage signals, and the magnetic flux signals. | 01-21-2010 |
20100072828 | PHASE CONTROL SWITCHING DEVICE - In a phase control switching device that controls a closing phase of a three-phase switching device connected between a power-supply-side transmission line and a compensation transmission line having a shunt reactor, a closing-phase control unit operates based on a closing command to the three-phase switching device, generates, for each phase, a closing phase in which the three-phase switching device is closed at zero points, both polarities of which are inverted into the same polarity, among zero points where zero points of a voltage changing ratio and zero points of the shunt reactor current coincide with each other, and controls the three-phase switching device. | 03-25-2010 |
20100085668 | PHASE-CONTROL SWITCHING APPARATUS AND SWITCHING CONTROL METHOD FOR PHASE-CONTROL SWITCHING APPARATUS - A residual-magnetic-flux calculating unit includes a voltage-change-rate detecting unit that detects a transformer-voltage change rate from a phase voltage between a breaker and a transformer, a residual-magnetic-flux detecting unit that detects a residual magnetic flux remaining on the transformer based on the phase voltage, and a breaker-switching-state identifying unit that detects a switching state of the breaker. The residual-magnetic-flux calculating unit recalculates the residual magnetic flux based on the transformer-voltage change rate and a predetermined threshold while the breaker is in an open state. | 04-08-2010 |
20110228437 | PHASE-CONTROL SWITCHGEAR AND METHOD OF CONTROLLING SWITCHGEAR - A phase-control switchgear includes a circuit breaker, a phase difference detection unit, a storage unit, and a circuit breaker control unit. The phase difference detection unit detects a phase difference between voltages of a specific phase (U-phase) of buses to which three-phase generators are respectively connected, at a plurality of time points. The storage unit stores the detected phase differences. When the three-phase generators are out of synchronization, the circuit breaker control unit estimates a breaking time point at which the phase difference between the voltages of the U-phase of the buses will be in the range of not less than −80° and not more than 80°, based on the phase differences at the plurality of time points stored in the storage unit. The circuit breaker control unit opens the circuit breaker to break a current at the estimated breaking time point. This makes it possible to suppress a transient voltage generated between electrodes of the circuit breaker after the current is broken. | 09-22-2011 |
20120236443 | INRUSH-CURRENT SUPPRESSING DEVICE AND INRUSH-CURRENT SUPPRESSING METHOD - An inrush-current suppressing device includes: a residual-magnetic-flux calculating unit that calculates a residual magnetic flux in a reference phase of a three-phase transformer while assuming a maximum magnetic flux level generated at a time of applying a rated voltage as 1 PU based on a measurement result of a transformer-voltage measuring unit before and after opening a three-phase circuit breaker; a stationary-magnetic-flux calculating unit that calculates a stationary magnetic flux in the reference phase of the three-phase transformer with reference to the maximum magnetic flux level obtained as the 1 PU based on a measurement result of a power-supply-voltage measuring unit, in response to a closing command to the three-phase circuit breaker; and a control unit that actuates a switch of the three-phase circuit breaker corresponding to the reference phase at a timing when the stationary magnetic flux and the residual magnetic flux in the reference phase match each other. | 09-20-2012 |
20150043120 | DIRECT-CURRENT CIRCUIT BREAKER - A direct-current circuit breaker includes a switching unit inserted in the direct-current line; and a commutation circuit that includes a series circuit including a first current-limiting element and an interrupting unit that forms a current zero point by superimposing a resonance current on a direct current flowing in the direct-current line and interrupts the direct current at the current zero point, that is connected in parallel with the switching unit, and that becomes a flow path for the direct current after the switching unit is opened, wherein current interruption is performed by the interrupting unit after the switching unit is opened. | 02-12-2015 |