Abstract: Disclosed herein is an apparatus for controlling an inverter. The apparatus determines the phase of an command voltage in a restart section taking into account the frequency of an input voltage to an electric motor when an input power is reduced below a rated power, the frequency of the input voltage into the electric motor at the time of restarting, a time period for generating a torque, and the phase of the input voltage to the electric motor at the time of the restarting.

Abstract: A fuse case and a case cover of a vacuum contactor including a truck, a main circuit unit, and a front cover covering a front side of the main circuit unit include a fuse connected to an upper terminal of the main circuit unit and blowing, when a fault current is generated in a circuit, to break the circuit, a fuse case opened in an upper side, accommodating the fuse, and having an insertion coupling part formed on a side surface thereof, and a case cover coupled to an upper side of the fuse case, coupled to the insertion coupling part in an insertion coupling manner, and covering a rear end portion of the fuse, wherein the case cover includes an upper surface portion and side surface portions, and the side surface portions include a first side surface portion and a second side surface portion.

Abstract: A bypass switch includes: a casing; a vacuum interrupter disposed inside the casing, the vacuum interrupter being disposed such that a movable contact is movable to a fixed contact; a first fixing bus-bar fixed to the casing; a second fixing bus-bar fixed to the casing to be spaced apart from the first fixing bus-bar; a moving pusher connected to the movable contact; a drive source installed in the casing, the drive source pushing the moving pusher to a position at which the movable contact and the fixed contact are contacted with each other; and a multi-contactor disposed to be contacted with the moving pusher. Accordingly, the moving pusher can rapidly contact the movable contact with the fixed contact. Further, the moving pusher can be moved with a small external force. Thus, it is possible to minimize the size of the drive source and the power used in the drive source.

Abstract: The present invention relates to a multi-pole molded case circuit breaker, more particularly, to a multi-pole molded case circuit breaker having a safety device (with an isolation function) which prevents a manipulation handle from being moved to an off-position when a fusion occurs on a contact portion.

Abstract: A door interlock device for a power transformer room in a vacuum circuit breaker includes a cam disposed on a shaft of a ground switch, a supporter disposed on a side plate of a power transformer room, a shaft disposed at the supporter to be slidable and having one end contacting the cam to be upward and downward movable, a spring disposed within the supporter to provide an upward elastic force to the shaft, and an interlock plate disposed at one side of the power transformer room door and configured to be in contact with the shaft.

Abstract: Disclosed embodiments relate to an auxiliary relay of an electronic contactor. In some embodiments, an auxiliary relay has its conducting state controlled by a plurality of lead switches, in a non-exposed state of contact parts to the outside. This may prevent dust or foreign materials from clinging to the contact parts.

Abstract: The present disclosure relates to a structure of a crossbar for a manual motor starter, and particularly, to a structure of a crossbar for a manual motor starter in which a function of an auxiliary lever is performed by a crossbar to thus reduce the number of components and an operational error. The structure of a crossbar for a manual motor starter (MMS) including a crossbar connected to an operating mechanism and an auxiliary contact lever operating an auxiliary contact, wherein a pressing unit is formed in the crossbar to operate the auxiliary contact lever upwardly.

Abstract: A high voltage direct current (HVDC) transmission system is provided. The high voltage direct current (HVDC) transmission system includes a rectifier converting alternating current (AC) power into DC power; an inverter converting the DC power into the AC power; DC transmission lines W1 and W2 transmitting the DC power obtained from the rectifier through conversion to the inverter; a first active power measurement unit measuring first active power input to the rectifier; a second active power measurement unit measuring second active power output from the inverter; and a first control unit controlling the operations of the rectifier and the inverter based on the first active power measured and the second active power measured, wherein the first control unit senses oscillation generated in the HVDC transmission system and generates a control signal for damping the sensed oscillation to control one or more of the rectifier and the inverter.

Abstract: The master device of Profibus DP according to the present disclosure automatically configures network by performing a communication with a plurality of slave devices connected through Profibus, the device including a Profibus communication module configured to perform a communication with a plurality of slave devices, an imaginary network configuration information storage configured to be stored in advance with imaginary network configuration information, a network configuration information storage configured to be stored with network configuration information, and a Profibus master state machine configured to obtain network configuration information by performing a communication with the plurality of slave devices in response to the imaginary network configuration information stored in the imaginary network configuration information storage, to store the obtained network configuration information in the network configuration information storage, and to perform a communication with the plurality of slave devi

Abstract: A system for measuring a loss in power between a power transmission side and a power reception side in a high voltage direct current (HVDC) system is provided. The system for measuring the loss in power includes: a first loss measurement unit installed at the power transmission side, and a second loss measurement unit installed at the power reception side, wherein each of the first and second loss measurement units is installed at a location at which a current or voltage is measured, and includes a voltage sensor for measuring a voltage, a current sensor for measuring a current, a GPS module for providing time information on when measurement is performed by the voltage sensor and the current sensor, and a storage unit storing the time information along with a voltage value and a current value measured by the voltage sensor and the current sensor.

Abstract: An apparatus for controlling an induction motor is provided, the apparatus generates generating a d-axis current command and a q-axis current command of a torque command, estimating speed of a rotor of the motor, and correcting the d-axis and q-axis current commands by using the estimated speed, to enhances the rotor speed and position estimation performance by increasing the slip frequency.

Abstract: The magnetic coil driving circuit of the magnetic contactor according to the present invention comprises a semiconductor switch configured to open or close a circuit for magnetizing or demagnetizing a magnetic coil; a pulse width modulation unit configured to output a pulse signal as a control signal for turning on or off the semiconductor switch; a control unit configured to output a control signal for changing a pulse width of the pulse signal to the pulse width modulation unit; and a temperature detection and protection unit configured to detect a temperature inside the magnetic contactor, output an output signal for turning off the semiconductor switch when the temperature exceeds an allowable temperature, and control the semiconductor switch by the pulse signal from the pulse width modulation unit when the temperature is within the allowable temperature.

Abstract: The present disclosure relates to an apparatus for warning of exceeding speed limit in railway vehicles, wherein a train speed is estimated after a predetermined time, a remaining time is calculated until a train reaches a speed limit based on the estimated speed, and when the calculated time is smaller than a preset reference value, a warning signal is generated. Thus, an adequate warning can be given to cater to a train operation situation because a TTSLC indicator is used that notifies when an emergency braking will be activated by exceeding a set speed limit value after a certain time lapses, resultantly increasing the train operation frequency and the availability of trains.

Abstract: In some embodiments, a driving circuit of a switching device for an electric power control capable of improving reliability of an ON/OFF driving and a monitoring operation of a switching device by configuring a configuration for the ON/OFF driving and the monitoring operation of the switching device in plural numbers is presented. A driving circuit of a switching device for an electric power control may include a driver circuit unit, a first logic device, a second logic device, and a controller.

Abstract: An interlock apparatus of a ring main unit is provided. The interlock apparatus may be provided between a plurality of switches which are included in the ring main unit and are adjacent to each other, and when one switch is controlled to a closed state and is connected to a power supply source, the other switch adjacent to the one switch is prevented from being connected to the power supply source, thereby preventing the plurality of switches from being simultaneously connected to the power supply source.

Abstract: A control apparatus in a static VAR compensator (SVC) system includes a plurality of current supply units for supplying phase currents configuring three-phase current of a power system, a plurality of current sensors for measuring the phase currents, and a controller for determining whether unbalance occurs in the three-phase current based on the phase currents, calculating an error corresponding to the unbalance according to the phase currents if unbalance occurs, and individually controlling at least one of the plurality of current supply units so as to compensate for the error.

Abstract: A control device in a high voltage direct current (HVDC) system is provided. The control device includes a communication unit performing communication with a component in the HVDC system; and a control unit enabling the communication unit to receive, from the component, data on an available state of the component, calculating availability of the HVDC system defined as a ratio of an actual operation time of the HVDC system to an operable time of the HVDC system based on data on the available state of the component, and then performing control of the HVDC system based on the data on the available state of the component and the availability of the HVDC system.

Abstract: The present invention relates to a draw out apparatus for an air circuit breaker, and more particularly, to a draw out apparatus for an air circuit breaker capable of allowing a circuit breaker body to be stopped at a preset position, by executing idling when an abnormal operation such as an over-draw in operation and an over-draw out operation occurs at the preset position such as a disconnect position, a test position or a connect position, and capable of preventing damage of a circuit breaker and a cradle.

Abstract: The present disclosure may include a base frame; a transformer panel module having a main frame and a transformer disposed at an upper side of the base frame; a high voltage panel module having a high voltage enclosure coupled to one side of the main frame and a high voltage switch mounted within the high voltage enclosure; and a low voltage panel module having a low voltage enclosure coupled to the other side of the main frame and at least one of a breaker and a fuse mounted within the low voltage enclosure, thereby having an advantage of facilitating a service work for maintenance on the transformer panel module, high voltage panel module and low voltage panel module as well as minimizing a service time.

Abstract: The present disclosure provides a server device in a supervisory control and data acquisition system, wherein the system includes multiples client devices and the server device, wherein the server device comprises: a communication module to communicate with the multiple client devices; and a data service module configured: when a first client device has registered a requirement for processing data, to allocate a task for processing the data based on the requirement; and/or when a second client device subscribes to the requirement, to control the communication module to publish the requirement to the second client device; to process the data using the task; and to control the communication module to send the processed data to the first and/or second devices.