Kabushiki Kaisha Toshiba

Tadashi Koshizuka

Minoru Saito

Shiro Maruyama

Hiroyuki Maehara

Yoshimasa Sato

Noriyuki Nagayama

Koji Suzuki

Keisuke Udagawa

Yoshiaki Ohda

Minoru Saitoh

Kei Kawasaki

Hiroshi Kusuyama

Kazuhisa Kanaya

Masayuki Sato

Masayuki Ando

Toshiyuki Uchii

Hiroshi Furuta

Norimitsu Kato

Tadashi Mori

Takanori Iijima

Takeshi Shinkai

Koichi Futagami

Yuki Matsui

Tomohiko Mitani

According to one embodiment, an excitation inrush current suppressing apparatus comprising: bus voltage measurement equipment which measures each phase voltage of the single-phase AC-side bus; transformer voltage measurement equipment which measures a single-phase-side voltage of the transformer; phase detector which detects a cutoff phase when opening the circuit breaker by monitoring each phase voltage measured by the bus voltage measurement equipment and the single-phase-side voltage measured by the transformer voltage measurement equipment, holds the detected cutoff phase, and outputs the same phase as the held cutoff phase; and close command output device which closes the circuit breaker by the same voltage phase as the cutoff phase output from the phase detector.

Excitation inrush current suppressing apparatus and excitation inrush current suppressing method

A pair of fixed arc electrodes are arranged facing each other within a sealed container that is filled with arc-extinguishing gas. There are provided: a compression puffer chamber for accumulating pressurized gas that is obtained by elevating the pressure of the arc-extinguishing gas; and an insulated nozzle that directs the pressurized gas towards the arc discharge from the compression puffer chamber. A buffer chamber is provided, in which hot exhaust gas generated by the heat of the arc discharge is temporarily accumulated. A pressurized gas through-flow space is provided, communicating with the compression puffer chamber. In the pressurized gas through-flow space, an opening/closing section prevents inflow of hot exhaust gas by assuming a closed condition during the earlier half of the current interruption period, and in the latter half of the current interruption period the opening/closing sectionis opened to allow flow of pressurized gas.

Gas circuit breaker

According to one embodiment, a magnetizing inrush current suppressing device is configured to measure a three-phase alternating current flowing from the power supply bus to the load, detect a first interruption phase as a phase of an electric current which is interrupted first among the three phases, detect a phase of a phase voltage zero point through which a phase voltage of the first interruption phase of the three-phase AC voltage passes when changing from the same polarity as that of an electric current immediately before interruption of the first interruption phase to an opposite polarity, and close the circuit-breaker at a phase within 60&#xb0; from the detected phase.

Magnetizing inrush current suppression device

A switch capable of easily accomplishing current cutoff roles required for a high-voltage switch, and which has a short breaking time. The switch includes pressure housings filled with an insulative medium, a plurality of contactors each including a contact, a plurality of operation units actuating the contacts, an insulative spacer dividing the interiors of the pressure housings into the same number of internal spaces as the number of contacts, and an electrode passing completely through the insulative spacer and fastened to the insulative spacer. The contactor is provided one by one for each internal space, and all contacts are electrically connected in series via the electrode, and the operation units actuate the corresponding contacts, respectively.

Switch

According to one embodiment, an excitation inrush current suppression device for suppressing excitation inrush currents flowing through a breaker of the three-phase collective operation type for opening and closing connection is configured to measure a three-phase AC voltage of the power supply bus bar to calculate prospective magnetic fluxes of the transformer, and to measure a three-phase AC voltage on the transformer side to calculate residual magnetic fluxes of the transformer after shutoff, so as to set the breaker closed when polarities of the prospective magnetic fluxes respectively agree with polarities of the residual magnetic fluxes in all of the phases respectively.

Excitation inrush current suppression device

According to one embodiment, there is provided an inrush current suppression apparatus that suppresses an inrush current generated when shunt capacitors are connected to a power system, the apparatus including a voltage measurement unit measuring power source voltages, a current measurement unit measuring circuit breaker currents, a polarity determination unit determining the polarities of residual voltages, a phase section detector detecting a phase section in which the polarities of the residual voltages match the polarities of the power source voltages, and a circuit breaker closing unit closing the circuit breaker within the phase section.

Inrush current suppression apparatus

An electromagnetic rebound mechanism unit and a magnetic latch unit are fixedly installed between a switchgear and a spring drive unit by virtue of a rebound fixing member and a fixing yoke. The electromagnetic rebound mechanism unit includes a rebound coil fixedly secured to the rebound fixing member, a reinforcing plate fixedly secured to a movable shaft and a rebound ring fixedly secured to the reinforcing plate. The magnetic latch unit includes a permanent magnet fixedly secured to the rebound fixing member, a latch ring fixedly secured to the permanent magnet and a movable yoke fixedly secured to the movable shaft. The spring drive unit includes a support frame, a spring retaining plate, a circuit-opening spring, a damper unit, and first and second electromagnetic solenoids.

Switchgear operating mechanism

According to an embodiment, when a transformer that is connected to a first power supply through a first breaker as well as to a second power supply through a second breaker is detected to be disconnected from the power supplies, a specific phase of the three phases of the first breaker is closed to suppress an excitation inrush current, based on calculated residual magnetic fluxes and a voltage of the first power supply, and thereafter, the remaining two phases are closed. Based on the calculated residual magnetic fluxes and a voltage of the second power supply, a specific phase of the three phases of the second breaker is closed to suppress an excitation inrush current, and thereafter, the remaining two phases are closed.

Excitation inrush-current suppression system

According to one embodiment, a magnetizing inrush current suppressing device includes, a first closing unit closes the circuit-breaker at the notable phase by the first phase determined by the first-phase determination unit, a second-phase determination unit determines a second phase at which the notable phase detected by the notable phase detection unit from the three-phase AC voltage measured by the power-supply-side voltage measurement unit becomes a zero point after the first phase determined by the first-phase determination unit, and a second closing unit closes the circuit-breaker at two phases other than the notable phase by the second phase determined by the second-phase determination unit.

Magnetizing inrush current suppressing device

According to one embodiment, there is provided an inrush current suppression apparatus that suppresses an inrush current generated when shunt capacitors are connected to a power system. The apparatus includes a power supply voltage measurement unit measuring a power supply voltage, a circuit breaker current measurement unit measuring a circuit breaker current, a residual voltage polarity determination unit determining the polarities of three phases of a residual voltage, a specific phase determination unit determining a specific phase, a closing phase detector detecting a closing phase, and a circuit breaker closing unit closing the circuit breaker in the closing phase.

According to one embodiment, there is provided a magnetizing inrush current suppression device. A closing phase determination unit determines a phase position for suppressing the magnetizing inrush current among phase positions in which the prospective magnetic flux calculated by the prospective magnetic flux calculation unit and the residual magnetic flux calculated by the residual magnetic flux calculation unit coincide between the lines of the minimum residual magnetic flux determined by the minimum residual magnetic flux determination unit, as a closing phase position. A closing unit simultaneously closes the three phases of the circuit-breaker at the determined closing phase position.

A residual magnetic flux estimation deviceincludes a DC power-source control devicewhich controls a DC power sourceto apply a DC voltage across two terminals of a &#x394; connection that is a secondary winding or a tertiary winding, a voltage measuring devicewhich measures a terminal voltage at the primary side of a three-phase transformera computing devicethat determines a phase having a high voltage between the two phases other than the phase to which the voltage is applied, and a residual magnetic flux measuring devicethat measures a phase-to-phase residual magnetic flux between the two phases other than the high-voltage phase, and estimates a measured value of the phase-to-phase residual magnetic flux as a maximum residual magnetic flux in the measurement-target three-phase transformer.

Method of estimating the residual magnetic flux of transformer and residual magnetic flux estimation device

According to one embodiment, there is provided a magnetizing inrush current suppression apparatus including an interrupting phase detection unit that detects a phase when the transformer that converts a three-phase alternating-current voltage to a single-phase alternating-current voltage is disconnected, a single-phase alternating-current voltage measurement unit that measures the single-phase alternating-current voltage on the power system side of the circuit breaker, and a closing unit that closes the circuit breaker in the detected phase, based on the measured single-phase alternating-current voltage.

Magnetizing inrush current suppression apparatus

In some embodiments, a method is disclosed that includes measuring a waveform of a power source side voltage of a circuit breaker; measuring a waveform of a transmission line side voltage of the circuit breaker; calculating a waveform of a voltage between contacts of the circuit breaker that is a difference between the waveform of the power source side voltage and the waveform of the transmission line side voltage; calculating a waveform of an absolute value of the waveform of the voltage between contacts; extracting a waveform of a component in a frequency band which is lower than a frequency of the power source and higher than a frequency of a DC component from the waveform of the absolute value; detecting a cycle of the extracted waveform; and closing the circuit breaker based on the cycle.

Overvoltage suppressing device

An overvoltage suppression device which suppresses overvoltage that occurs when breakers which turn on/off the connection between a power source bus and a power transmission line, are turned on after the breakers are turned off. The overvoltage suppression device measures the waveform of voltage on the side of the power source and the voltage on the side of the power transmission line, and extracts the waveform of a component in a predetermined frequency band on the basis of the waveform obtained by multiplying the wave shape of the voltage on the side of the power source by the waveform of the voltage on the side of the power transmission line. The breakers are turned on on the basis of a cycle wherein the waveform is peaked.

Growing community of inventors

Saitama, Japan

Tadashi Koshizuka