US Pat. No. 10,143,093

MODULAR APPARATUS FOR HIGH VOLTAGE DIRECT-CURRENT TRANSMISSION SYSTEM

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1. A modular apparatus for a high-voltage direct-current transmission system, the apparatus comprising:a housing forming an external shape;
a display unit disposed on an inclined surface formed at a front lower portion of the housing and inclined with respect to the ground; and
a control board disposed in an installation space at a lower portion in the housing and controlling components in response to control signals transmitted from a controller located outside the housing through a cable,
wherein the display unit shows states of the components and is connected with the cable for connection with the controller, and
wherein a connector for connection with the cable is disposed at the control board.

US Pat. No. 10,177,652

POWER SUPPLY DEVICE FOR SUB-MODULE CONTROLLER OF MMC CONVERTER

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1. A power supply apparatus for a sub-module controller of a MMC, comprising:a bridge circuit unit including N (N?2, integer) energy storage units for storing a DC voltage in series-connected sub-modules in the MMC, and multiple power semiconductor devices respectively connected in parallel with the N energy storage units in a form of a bridge and connected in series with each other;
a switching unit for switching any one of a first output terminal formed at a first end of n (1?n a DC/DC converter for converting a voltage, output through the first output terminal or the second output terminal depending on switching of the switching unit, into a lower voltage than the output voltage, and supplying the lower voltage to the sub-module controller.

US Pat. No. 10,181,387

ELECTROMAGNETIC REPULSION ACTUATOR FOR CIRCUIT BREAKER

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1. An electromagnetic repulsion actuator for a circuit breaker, comprising:a housing;
a first fixed electrode provided inside the housing and having therein an operating space open at both sides;
a pair of movable electrodes installed in the first fixed electrode at the both sides of the operating space thereof, the movable electrodes being capable of reciprocally moving and being electrically connected to the first fixed electrode;
second fixed electrodes respectively spaced apart from the first fixed electrode and installed inside the housing at both sides thereof, and selectively contacting the pair of movable electrodes to be electrically connected thereto, thereby transferring power supplied from a first side to a second side; and
actuating coils selectively moving the movable electrodes in directions of being separated from the second fixed electrodes by generating electromagnetic force from induced current.

US Pat. No. 10,176,939

HIGH-VOLTAGE DC CIRCUIT BREAKER FOR BLOCKING CURRENT FLOWING THROUGH DC LINES

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1. A high-voltage DC circuit breaker for blocking current flowing through a DC line, comprising:a main switch connected to the DC line, and configured to be opened when a fault occurs on a first side or a second side of the DC line, thus blocking a current flowing through the DC line;
an LC circuit connected in parallel with the main switch and provided with a capacitor and an inductor connected in series with each other to produce LC resonance;
a first switching element connected in parallel with the LC circuit and configured to perform switching so that a positive voltage or a negative voltage stored in the capacitor via the resonance produced by the LC circuit is charged, with a polarity of the positive or the negative voltage changed; and
a second switching element connected in series with the LC circuit, connected in parallel with the main switch and connected between the LC circuit and the DC line, the second switching element performing switching so that a current pulse, generated by the positive or negative voltage charged in the capacitor, is supplied to the main switch,
wherein the first switching element and the second switching element are connected in a forward direction, are each arranged in a forward or reverse direction relative to a direction of current flowing from the second side to the first side of the DC line, and are each implemented using one or more power semiconductor switches,
when the main switch is opened due to occurrence of a fault on the second side of the DC line, and an arc is formed when the main switch is opened, and the second switching element is turned on in a state in which the first switching element is turned off, so that the current pulse generated by the positive voltage stored in the capacitor of the LC circuit is supplied in a direction of a second end of the main switch, and zero current is realized in the main switch using the supplied current pulse, thus enabling the arc formed in the main switch to be extinguished, and enabling the negative voltage to be charged in the capacitor,
wherein, after the arc formed in the main switch has been extinguished, the negative voltage charged in the capacitor is charged as the positive voltage via the resonance produced by the LC circuit when the first switching element is turned on in a state in which the second switching element is turned off, and thereafter the first switching element is turned off.

US Pat. No. 10,176,947

HIGH-VOLTAGE DC CIRCUIT BREAKER FOR BLOCKING DC CURRENT

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1. A high-voltage DC circuit breaker, comprising:a mechanical switch installed on a DC line;
an LC circuit including a capacitor and a reactor connected in parallel with the mechanical switch, and connected in series with each other so as to cause LC resonance;
a first semiconductor switch connected in series with the LC circuit and configured to switch a flow of current in one direction; and
a second semiconductor switch connected in parallel with the first semiconductor switch and configured to switch a flow of current in a direction opposite the one direction,
wherein, in a steady state, the first and second semiconductor switches are turned off, and a current flowing through the DC line is supplied to the capacitor to enable an initial voltage to be charged in the capacitor,
wherein, when a fault occurs on one side of the DC line, the mechanical switch is opened and the first semiconductor switch is turned on in a state in which the second semiconductor switch is turned off, a current by the initial voltage charged in the capacitor flows through an arc formed in the mechanical switch and the first semiconductor switch, and then LC resonance occurs in the LC circuit and a polarity-reversed voltage is charged in the capacitor via the LC resonance in the LC circuit,
wherein a current by the polarity-reversed voltage flows to the mechanical switch to extinguish the arc formed in the mechanical switch, and
wherein, when the arc is extinguished, both the first and second semiconductor switches are turned off, and a current flowing through the DC line is supplied to the LC circuit, so that the capacitor is recharged to the initial voltage.

US Pat. No. 10,170,903

HIGH VOLTAGE DC CIRCUIT BREAKER

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1. A high-voltage DC circuit breaker for breaking a current that flows in a DC line, comprising:a main switch (110), installed on the DC line, for breaking a current of the DC line by opening when a fault occurs on one side or a remaining side of the DC line;
a nonlinear resistor (120) connected in parallel with the main switch (110);
an LC circuit (130) that is connected in series with both the main switch (110) and a first bidirectional switching element (140), and includes a capacitor (131) and a reactor (132), which are connected in series in order to generate LC resonance;
the first bidirectional switching element (140), is for switching a bidirectional current flow; and
a second bidirectional switching element (150), connected in parallel with the LC circuit (130), for switching a current flow to induce LC resonance in both directions.

US Pat. No. 10,199,988

METHOD FOR CONTROLLING POWER GRID FREQUENCY OF MULTIPLE ENERGY STORAGE SYSTEMS, AND SYSTEM THEREFOR

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1. A power grid frequency control system for controlling a power grid frequency for multiple energy storage systems using a hierarchical control structure, comprising:a plurality of energy storage systems (ESSs);
a local management system (LMS) configured to manage at least one of the energy storage systems on a local basis;
an energy storage system controller (ESS controller) configured to generally control the local management system by determining a state of the local management system, estimating an output value of at least one of the energy storage systems belonging to the local management system, and transmitting the estimated output value to each energy storage system; and
a power management system (PMS) configured to generally manage overall systems including the plurality of energy storage systems, the local management system, and the energy storage system controller, determine states of the overall systems to allow a user to participate in a power grid frequency control market by making a contract with a system operator, control an output value of the local management system, and regulate control parameters for controlling the output value, wherein, when a plurality of energy storage system controllers are provided, the power management system determines control parameters for controlling frequencies of the energy storage system controllers, sets a participating energy ratio for a frequency response and frequency regulation control depending on a frequency state on the basis of the determined control parameters, and performs the frequency response and frequency regulation control depending on the set participating energy ratio,
wherein the power management system analyzes the power grid frequency and an automatic generation control (AGC) signal, makes a normal distribution of the power grid frequency and the AGC signal within a particular time interval, calculates an output expectation value for the frequency response control and an output expectation value of the AGC signal for the frequency regulation control within the particular time interval, optimizes the participating energy ratio for the frequency response and the frequency regulation for a day, and sets a result of the optimization as the participating energy ratio for the frequency response and the frequency regulation.