668 results about "Dc circuit breaker" patented technology

The invention provides a photovoltaic DC circuit breaker fault diagnosis method and system, and relates to the technical field of fault diagnosis, and the method specifically comprises the steps: obtaining key parameters of equipment, calculating the instantaneous power, the current change rate, the temperature change rate and the energy consumption in unit time based on the key parameters, and carrying out the calculation of the instantaneous power when the instantaneous power is calculated, introducing a total harmonic distortion correction power factor; analyzing the correlation between each key index and the fault evaluation index by using a Pearson's correlation coefficient method, and calculating to obtain the fault evaluation index; and a dynamic threshold adjustment mechanism is introduced to judge whether the photovoltaic direct-current circuit breaker has a fault or not. Through a dynamic threshold adjustment mechanism and Pearson's correlation coefficient analysis, the fault diagnosis capability of the photovoltaic DC circuit breaker is improved. Compared with a traditional method, the scheme realizes high-frequency data acquisition and real-time analysis, ensures accurate evaluation of the operation state, effectively identifies potential fault risks, and reduces the probability of equipment damage.

The invention relates to a direct-current circuit breaker based on a thyristor and an on-off method of the direct-current circuit breaker, and belongs to the technical field of direct-current middle-high voltage power system fault protection. The direct-current circuit breaker comprises a main switch branch, a current transfer branch, a voltage-limiting energy consumption branch and a pulse commutation loop, the direct-current circuit breaker is connected with a power system in series, and the main switch branch is connected with the current transfer branch. Two nodes connected in series are respectively marked as Q1 and Q2, the main switch branch and the voltage-limiting energy consumption branch are connected in parallel through the Q1 and Q2, one ends of secondary sides of two high-frequency transformers in the pulse commutation loop are respectively connected to the Q1 and Q2, and the other ends of the secondary sides of the two high-frequency transformers in the pulse commutation loop are respectively connected to two ends of the current transfer branch. The problem that in the prior art, a large number of pulse charging and discharging loops are configured for meeting the fault large-current breaking requirement, and consequently the size and cost are increased is effectively solved.

The invention relates to the technical field of power electronic devices, in particular to a low-voltage direct-current circuit breaker, a fault protection method and a related device.The low-voltage direct-current circuit breaker comprises a through-flow branch, a transfer branch and an energy consumption branch which are connected in sequence; the through-current branch comprises an isolating switch and an MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) commutation switch which are connected in series; the transfer branch comprises a first power electronic switch group and a buffer branch which are connected in parallel; the energy consumption branch comprises a first metal oxide MOV, a second metal oxide MOV and a second power electronic switch group; the first metal oxide MOV is connected in parallel with the second power electronic switch group; and the second metal oxide MOV is respectively connected with the first metal oxide MOV and the second power electronic switch group. The technical problems that an existing hybrid direct current circuit breaker is not suitable for a low-voltage direct current system and the loss is high in the turn-off process are solved.

The invention relates to the technical field of direct-current circuit breaker manufacturing, in particular to a direct-current circuit breaker with a rapid current suppression capability and a working method of the direct-current circuit breaker. The main branch is a line from the L side to the R side and sequentially passes through a secondary side winding N2 of the coupling inductor and a pair of anti-parallel thyristors. Each of the four charging branches comprises a diode and is matched with a resistor of the charging resistor branch to provide a charging loop for two capacitors in the two capacitor branches, and two buffer branches are respectively connected in parallel with the two capacitor branches. After a thyristor of the trigger branch is triggered, a capacitor of the capacitor branch can transmit energy to N2 in the main branch through a primary side winding N1 of a coupling inductor in the energy transfer branch, and then bidirectional current is cut off. The direct-current circuit breaker is designed by using the coupling inductor and the thyristor, and the direct-current circuit breaker has the advantages of high efficiency, rapid current suppression, good controllability, reprotection after reclosing, low cost and high reliability in the current breaking process.

Gate control of power semiconductor devices using reduced gate drivers is disclosed. A circuit breaker may include a multitude of transistors, such as insulated gate bipolar transistors (IGBTs), connected in series with one another. Each transistor may be connected to a respective gate resistor. Diodes may be connected between various gate resistors. One or more resistor-capacitor (RC) snubber circuits may be provided in parallel with one or more of the transistors. Likewise, one or more metal-oxide varistors (MOVs) may be connected in parallel to one or more of the transistors. A gate driver (e.g., a single gate drive) may be connected to the one or more diodes and an emitter of at least one of transistors.

The invention provides a control method and system for an energy storage PCS with an AC / DC circuit breaker and a storage medium, and the method comprises the steps: firstly, synchronously collecting the electrical parameters of a DC side and an AC side, and carrying out the preprocessing of the collected data, so as to form a standardized electrical matrix; then, all parameters in the electrical matrix are cyclically compared with corresponding early warning thresholds, first-level thresholds, second-level thresholds and fusing thresholds in a multi-level threshold mapping table; if the pre-warning threshold value is exceeded, a log is recorded, if the pre-warning threshold value is exceeded, self-healing operation is executed, if the pre-warning threshold value is exceeded, turn-off operation is executed, and if the pre-warning threshold value is reached, physical fusing is triggered; meanwhile, all operation logs are recorded, and the threshold mapping table is dynamically optimized by analyzing log data; according to the method, the fault response speed and the protection precision are improved through multi-level threshold serial comparison and a cooperative protection mechanism, the stability and the reliability under different working conditions are enhanced through the adaptive learning capability, and meanwhile, the whole life cycle cost is reduced.

The invention relates to an economical direct-current circuit breaker with zero-region rapid recovery capability and a control method. The circuit breaker solid state topology comprises a main through-flow branch, a resonance commutation loop, a damping energy consumption loop, a capacitor reset loop, a weak current breaking loop, a pre-charging branch and an MOV energy release module. When it is judged that the system has a short-circuit fault, fault current is introduced into a resonance commutation loop and a damping energy consumption loop, the short-circuit fault is rapidly removed, and safe opening time is provided for a vacuum switch of a main through-flow branch; if special conditions such as manual system maintenance are judged, a weak current on-off loop is put into use; a capacitor of a resonant circuit does not need to be externally provided with a charging circuit, a main through-flow branch adopts a vacuum switch to replace a power electronic device, a fault processing module adopts a half-control device, and the economic performance of the whole machine is excellent; the capacitor reset loop recovers the preset voltage of the capacitor, and the secondary breaking capacity of the circuit breaker is ensured under the medium-high voltage working condition. The device has good use value and economic benefit in the field of direct current power transmission and distribution and the like.

The invention discloses a hybrid DC circuit breaker, a control and protection device and a control and protection method. Three independent merging units of the device are used to collect the line current of the total outgoing line at one end of the hybrid DC circuit breaker, the main branch current, the transfer branch current, the total current of the energy-consuming branch and the branch current of the energy-consuming branch; the communication module of the control and protection host realizes the communication between the main branch, the transfer branch, the converter station control equipment and the converter station protection equipment; the protection judgment module performs overcurrent judgment of the circuit breaker according to the current of the merging unit; the three-out-of-two logic module performs three-out-of-two logic judgment of overcurrent according to the judgment result of the protection judgment module; the control module realizes the circuit breaker opening and closing timing and equipment fault judgment, and sends the control and protection instructions to the main branch commutation component and the semiconductor component of the transfer branch through the communication module and the interface unit; the protection method based on the device can quickly execute the opening and closing process, quickly detect the equipment status and implement effective protection.

The invention relates to a direct current fault ride-through method, a direct current fault ride-through device, direct current fault ride-through equipment and a medium. The method comprises the following steps: switching a control mode of network-forming type energy storage into an alternating-current voltage control mode or a direct-current control strategy, carrying out coordinated control on devices in a multi-terminal direct-current collecting and sending-out system, clearing fault current, and clearing the fault current by utilizing an active step-down control strategy or the direct-current control strategy at the same time. According to the method, measures such as additional direct current circuit breakers are not needed, control is flexible and easy to achieve, the multi-terminal direct current collecting and sending-out system after fault clearing is controlled to be recovered by judging the operation state of the multi-terminal direct current collecting and sending-out system, and safe and stable operation of the multi-terminal direct current collecting and sending-out system is facilitated.

The invention relates to the technical field of energy storage, and discloses a synchronous test platform for multiple energy storage converters and a control method of the synchronous test platform. The test platform comprises a wire inlet switch, a pre-charging loop, a transformer, an auxiliary power supply switch, an alternating-current circuit breaker, a direct-current circuit breaker and a unit controller, a power grid is connected to the high-voltage side of the transformer through the wire inlet switch and the pre-charging loop in sequence, and one side of the alternating-current circuit breaker is connected with a winding on the low-voltage side of the transformer. The direct current side of the first group of energy storage converters is connected with the direct current side of the second group of energy storage converters through the direct current circuit breaker, and the first group of energy storage converters is connected with the auxiliary power supply. According to the test platform, the pre-charging loop is bypassed after the first group of PCS is pre-charged, then the first group of PCS unlocks the direct current voltage control mode, and the second group of PCS starts in sequence control, so that the synchronous charging and discharging test of 2N PCSs is realized, and the charging and discharging test efficiency of the energy storage converter is greatly improved.

The invention relates to a high-voltage direct-current power transmission technology, and aims to provide a direct-current fault ride-through method and device based on energy-consuming damping and a circuit breaker and a medium. The method comprises the following steps: reducing the AC side voltage of a converter valve, and transferring a fault current to an energy consumption damping module in the MMC converter valve, so that an electromotive force enters a new steady state stage; the direct current fault current is gradually reduced, the direct current circuit breaker executes breaking operation, and a direct current fault point is completely isolated from the high-voltage flexible direct current power transmission system; a control strategy when the MMC converter valve operates normally is recovered, the energy consumption damping module is cut off step by step, and the MMC sub-module is put into operation at the same time, so that the high-voltage flexible direct-current power transmission system is stably transited to the normal operation state. Impact and damage risks of fault current on system equipment can be effectively reduced, and safe and stable operation of the system is guaranteed; a direct-current circuit breaker with a smaller capacity can be adopted, so that the purchase cost of equipment is remarkably reduced; the system stability can be kept under the fault condition, and the power supply reliability is improved.

The invention provides a direct-current circuit breaker with an arc discharge detection function and a control method thereof, the direct-current circuit breaker comprises a solid-state circuit breaker and an arc discharge detection assembly connected with the solid-state circuit breaker, and the solid-state circuit breaker at least comprises a power electronic device branch, a mechanical switch or contactor, an energy absorption device, a power panel and a control panel, the mechanical switch or the contactor is connected in series on a main branch of the direct current circuit breaker, the power electronic device branch is connected in parallel with the mechanical switch or the contactor, the energy absorption device is connected with the power electronic device branch, and the control panel and the power panel are connected with the power electronic device branch, the mechanical switch or the contactor and the arc discharge detection assembly. An arc discharge detection function is added, so that an arc discharge fault can be disconnected more quickly and accurately; and by setting the branch conduction time of the power electronic device, the on-off time of the direct current circuit breaker is further shortened, safer protection is provided for the system, and the reliability and engineering practicability of the direct current system are further improved.

The invention discloses a multi-port direct current change-over switch based on a controllable negative voltage source, and belongs to the technical field of power equipment. Comprising X (X = 5 or 3) main branches, a commutation branch and X groups of controllable conduction switches, each main branch is composed of a through-flow vacuum switch, and the commutation branch is composed of a controllable negative voltage source and a square wave resonance direct current circuit breaker which are connected in series. The five main branches of the sending end are connected with a sending end positive pole rectifier and the like, and the three main branches of the receiving end are connected with a receiving end positive pole rectifier and the like and are all connected with the commutation branch through a controllable conduction switch. The controllable negative voltage source is formed by connecting a double-thyristor branch circuit and a negative voltage source in parallel, and the square wave resonance direct current circuit breaker comprises a temporary through-flow branch circuit and the like. The vacuum switch is used for replacing an SF6 switch, so that the switch is good in environmental protection property; the converter branch and the lightning arrester are shared, so that the use of high-price equipment is reduced, and the cost is reduced; a controllable square wave voltage source is utilized to excite high-frequency oscillation of an LC branch, and the element size is reduced; and rapid transfer of current in different directions can be realized, and the system response speed is improved.

The invention provides a bidirectional series hybrid DC circuit breaker and a control method thereof, and relates to the technical field of power equipment. The bidirectional series hybrid DC circuit breaker comprises a main branch, a charging circuit and a voltage injection unit. The main branch comprises a mechanical switch, a current-limiting inductor, a first coupling inductor and a secondary winding; the voltage injection unit comprises a capacitor, a first H-bridge unit, a second H-bridge unit, a first coupling inductor primary winding and a second coupling inductor; and one end of the charging circuit is connected with the main branch, and the other end is connected with the voltage injection unit for charging the capacitor. In addition, the invention also provides a control method of the bidirectional series hybrid DC circuit breaker. According to the bidirectional series connection type hybrid direct current circuit breaker provided by the invention, the capacitor is charged by recovering the residual exciting current in the coupling inductor, and the voltage of the capacitor and the exciting current of the coupling inductor can be recovered to the initial state, so that self-weight starting is realized, and fault current can be bidirectionally broken.

The invention relates to an adjustable manual zero-crossing loop topology for assisting on-off of a direct-current circuit breaker. The pulse current can be flexibly adjusted under the working condition that the current amplitude of a main loop changes greatly, so that the on-off operation of the circuit breaker is assisted. The topological structure comprises a thyristor H bridge for controlling the current direction, and a discharge branch circuit connected in parallel at two ends of a direct current circuit breaker, wherein the branch circuit is formed by connecting a plurality of groups of capacitors and reactors in parallel. In the on-off process of the direct-current circuit breaker, the corresponding thyristors and the discharge switches are controlled to be switched on according to the amplitude of current in a main loop, the capacitor releases charges, and pulse current opposite to the current in the main circuit is generated through the electric reactor, so that the direct-current circuit breaker is assisted to complete on-off operation. According to the topological structure, the number of the input capacitors can be selected according to the amplitude of the main loop current, so that the reverse current matched with the main loop current is generated, and the switching-on and switching-off success rate of the circuit breaker is improved.

Examples described herein provide a system for controlling power flow in an energy distribution network. The system includes a plurality of inverters, each having an inverter controller associated therewith. The system further includes a utility controller associated with a utility and configured to communicate with at least a subset of the plurality of inverters. The system further includes a customer controller associated with a customer of the utility and configured to communicate with at least the utility controller. The system further includes a direct current (DC) breaker associated with a battery of the customer. The system further includes a DC meter of the customer, the DC meter and the DC breaker each configured to communicate with the utility controller and the customer controller. The utility controller is configured to determine a current operational scenario of the energy distribution network and to control power routing within the energy distribution network.

The invention discloses a flexible direct-current power transmission system and a fault ride-through method and system thereof. The flexible direct-current power transmission system comprises a main control module, and a new energy sending-out system, an alternating-current energy consumption device, a sending-end converter, a direct-current circuit breaker, a receiving-end converter and a receiving-end alternating-current power grid which are connected in sequence, the direct current circuit breaker is deployed on a direct current power transmission line between the sending end converter and the receiving end converter, and the receiving end converter is a modular multi-level converter formed by cascading a plurality of half-bridge sub-modules with damping branches; the main control module is in communication connection with the half-bridge sub-modules, the direct-current circuit breaker and the alternating-current energy consumption device and used for controlling the damping branches of the half-bridge sub-modules in the running state, the direct-current circuit breaker and the alternating-current energy consumption device to act when a direct-current fault occurs so as to restrain direct current and adjust direct-current voltage to be within a set voltage range. Therefore, no-locking fault ride-through is completed. According to the invention, high-reliability and low-cost DC fault ride-through can be realized.

The invention discloses an automatic cooling circulation system and method for a high-voltage direct-current circuit breaker, and the system comprises a machine body water jacket nested at the outer side of the circuit breaker, takes away the heat generated by the circuit breaker through the circulating flow of a cooling liquid, provides cooling liquid circulation power through a water pump, and increases the heat dissipation area of the cooling liquid through a heat dissipation net. Heat exchange between cooling liquid and air is conducted, a fan is used for blowing air to a heat dissipation net, heat dissipation is accelerated, meanwhile, electric arcs of a circuit breaker are lengthened through blowing, impedance of the circuit breaker is increased, the system is connected into a diaphragm type expansion tank and a water tank, and the pressure in a cooling circulation system pipeline is adjusted. The system is high in automation operation degree, the fan and the water pump can be prevented from being in a high-power working state under the condition that the temperature is not high, the service life of equipment is prolonged, meanwhile, the system can meet the requirements of different temperature working conditions, and the application range is wide.

The invention discloses a self-adaptive distributed energy and load plug-and-play direct current micro-grid ground fault protection method, system and device and a medium, and the method comprises the following steps: calculating fault area positioning information in real time, and when the area fault grounding current and the power change rate meet the protection starting criterion, starting a protection starting process; a fault area is determined according to the fault area positioning information, a tripping instruction is sent to a direct-current circuit breaker connected with the fault area, and the direct-current circuit breaker is disconnected after receiving the tripping instruction. According to the characteristics of flexible and changeable source storage load area structure, various control modes, easy extraction of fault high-frequency quantity and the like in the direct-current micro-grid, a universal protection positioning method is established by adding a constant-power load simulation actual scene in a load area; the plug-and-play performance of the fault protection positioning method under the condition that the DC micro-grid source storage load structure is changeable is realized, and accurate isolation of different fault areas when the DC micro-grid source storage load has a grounding short circuit fault is ensured.

The invention discloses an offshore wind power direct current networking system sharing an energy consumption device and a fault ride-through method, an offshore MMC current converter is connected through a direct current connection submarine cable at the direct current side of the offshore MMC current converter of the offshore wind power direct current networking system, and a direct current circuit breaker optimal configuration scheme is provided. According to the method, the direct current energy consumption device only needs to be configured on the direct current side of one offshore MMC converter, fault ride-through operation of the whole direct current networking system under different faults can be achieved through a coordination control strategy among the land MMC converter, the offshore MMC converter and the direct current energy consumption device, the construction cost of an offshore wind power direct current networking project is remarkably reduced, and the fault ride-through operation of the whole direct current networking system under different faults can be achieved. Good application prospects are realized.

The invention discloses a bidirectional power electronic switch, a hybrid DC circuit breaker and a control method. The bidirectional power electronic switch comprises a diode bridge module, a buffer circuit, a voltage limiting circuit and an impedance adjusting circuit. The impedance adjusting circuit is connected in parallel with two ends of the diode bridge module; the buffer circuit is connected in parallel with a breaking electronic switch in the diode bridge module; the voltage limiting circuit is connected in parallel with two ends of the breaking electronic switch; the diode bridge module controls the breaking electronic switch to switch current according to a breaking instruction of the power system; when the breaking electronic switch is locked, the buffer circuit suppresses the voltage and current changes of the breaking electronic switch in the switching process, the voltage limiting circuit limits the overvoltage level of the breaking electronic switch, and the impedance adjusting circuit reduces the oscillation frequency. The impedance adjusting circuit reduces the oscillation frequency, reduces the requirement for the reverse recovery speed of the diode, reduces the stress of the diode bridge type module, and enables a conventional common diode to be not liable to be damaged.

This invention relates to the field of energy storage technology and discloses a synchronous testing platform for multiple energy storage converters and its control method. The testing platform of this invention includes: an incoming line switch, a pre-charge circuit, a transformer, an auxiliary power supply switch, an AC circuit breaker, a DC circuit breaker, and a unit controller. The power grid is connected to the high-voltage side of the transformer sequentially through the incoming line switch and the pre-charge circuit. One side of the AC circuit breaker is connected to the windings on the low-voltage side of the transformer, and the other side is connected to the AC side of the energy storage converter. The DC side of the first group of energy storage converters is connected to the DC side of the second group of energy storage converters through DC circuit breakers. The first group of energy storage converters is connected to the auxiliary power supply. In this invention, after the first group of PCS (Power Storage Converters) is pre-charged, the pre-charge circuit is bypassed. Then, the first group of PCS is unlocked and controlled in DC voltage mode, and the second group of PCS is started sequentially, thereby achieving synchronous charging and discharging testing of 2N PCS, greatly improving the charging and discharging testing efficiency of the energy storage converter.

The invention discloses an online detection method for a medium and low voltage direct current circuit breaker, and relates to the technical field of power system protection control, and the method comprises the following steps: S001, building a radiation echo spectrum distribution model during the switching operation of the direct current circuit breaker, calculating an interference intensity estimated value through collecting a current drop rate and a fracture voltage climbing rate, and calculating the interference intensity estimated value according to the current drop rate and the fracture voltage climbing rate; and extracting a disturbance frequency band with concentrated interference energy and generating a characteristic signal set for representing an interference propagation path. According to the method, a closed-loop anti-interference mechanism is constructed through feature modeling, interference recognition, signal correction and parameter optimization, the stability and accuracy of state judgment are improved, misjudgment and response failure caused by high-frequency interference are prevented, the method is particularly suitable for a complex parallel system and a frequent on-off scene, and the safety and the intelligent level of a direct-current system are effectively enhanced.

The invention provides a direct-current circuit breaker and a control method thereof, and belongs to the technical field of direct-current middle-high voltage power system fault protection. The short circuit turn-off branch comprises a first capacitor and a first thyristor; the coupling commutation branch comprises a first inductor, a second inductor, a second thyristor and a third capacitor; the rated turn-off branch comprises a first resistor and a second capacitor; the first resistor, the second capacitor, the first capacitor and the second inductor are sequentially connected in series and then are connected with the main switch branch in parallel; the first inductor, the second thyristor and the third capacitor are sequentially connected in series, and the first inductor and the second inductor form mutual inductance. By controlling the on-off of the first thyristor, the first capacitor and the second capacitor are connected in series, the capacitance value is reduced, large-capacitance-value operation of a single group of capacitors is realized, and the problem that the on-off time of rated and lower low-current breaking is relatively long can be solved.

The invention relates to a resistance-capacitance type inductive hybrid direct current circuit breaker and a control method thereof. When overcurrent occurs in the system, the current transfer branch is input to realize reversing of fault current, a resistor in the current transfer branch shunts the fault current, the amplitude of the fault current and the voltage rise rate of a circuit breaker port are effectively inhibited, and it is ensured that the mechanical switch can reliably complete breaking. Capacitors in the current transfer branch and the breaking branch do not need additional pre-charging circuits, the overall size of the circuit breaker is reduced, only mechanical switch reactive power devices are connected in series in the through-flow branch, and the loss of normal work of a system is reduced; the breaking capacitor and the thyristor replace a traditional full-control device, so that the overall economical efficiency of the circuit breaker is greatly improved; and meanwhile, the reliability of the system is further improved by phase selection on-off and small current on-off of the circuit breaker.

The invention discloses a land wind power transmission system, which is used for solving the problems of alternating current collection and transmission such as harmonic resonance and reactive power transmission in the prior art. The land wind power transmission system comprises a wind power sending end unit and a wind power receiving end unit. The wind power sending end unit comprises a direct current transformer and more than two wind turbine generators; a generator-side converter is arranged in each wind generator set and corresponds to one low-voltage circuit breaker; two poles of the direct-current transformer are respectively provided with a direct-current circuit breaker; for each wind power generation set, electric energy generated by the wind power generation set is rectified into first direct current through a machine-side converter, and the first direct current is connected into a direct-current transformer in parallel through a low-voltage circuit breaker to be boosted into second direct current which is sent into a wind power receiving end unit through a bipolar direct-current circuit breaker of the direct-current transformer; the wind power receiving end unit comprises a receiving end converter station, a connection transformer and a starting loop; and the second direct current is subjected to secondary boosting through the connection transformer after being subjected to current conversion through the receiving-end converter station, and is accessed to the alternating-current power grid through the starting loop.

The utility model relates to a quick mechanical switch of a bipolar direct current circuit breaker, which belongs to the field of quick mechanical switches and comprises a switch body, an electromagnetic repulsion operating mechanism, a driving circuit, a position detection unit and a control unit. The switch body comprises a vacuum arc-extinguishing chamber, at least one static contact and at least one moving contact, the direct current positive bus is provided with a positive switch fracture, the direct current negative bus is provided with a negative switch fracture, the static contacts are respectively arranged at two ends of the positive switch fracture and the negative switch fracture, and the moving contact is opposite to the static contacts; the control unit controls the driving circuit to drive the magnetic repulsion operating mechanism to switch on or switch off the rapid mechanical switch according to the switching-on state or the switching-off state, detected by the position detection unit, of the rapid mechanical switch. Reliable breaking of a direct-current bus fracture is realized through driving of the two series coils on the sides of the direct-current positive bus and the direct-current negative bus, the action consistency of a mechanical switch is improved, and the size and the cost of a product are reduced.

The invention provides a medium-voltage direct-hanging multi-level energy storage grid-connected direct-current fault isolation method and device. The method comprises the following steps of: establishing corresponding protection partitions on a phase arm, a bus section and a battery cluster, configuring a polarity controllable blocking sub-module capable of being inserted with reverse voltage on the phase arm, and respectively configuring direct-current circuit breakers on the bus section and the battery cluster; generating a criterion set based on the measured value, and performing consistency voting on the criterion set to obtain a direct current fault determination result and a partition positioning result; when a fault is determined, issuing modulation and zero setting, and calculating a reverse equivalent voltage according to the change rate of the phase arm current and the target current to trigger the insertion of a polarity controllable blocking sub-module; selectively driving a corresponding direct current circuit breaker to be switched on and off according to a partition positioning result, or splitting a fault phase arm; and after selective switching-off is completed, outputting an isolation state to a grid-connected control unit of the energy storage grid-connected system. According to the invention, millisecond-level robust fault discrimination, partition selective isolation, cooperation of current limiting and on-off can be realized, and the removal range is narrowed.

The invention discloses an RC-IGCT-based superconducting hybrid DC circuit breaker, and relates to the topological structure and working principle analysis of DC circuit breakers. The circuit topology comprises two parts: (1) a resistance-type superconducting fault current limiter R-SFCL and a UDS isolation switch adopting a TP KEMA arc model are connected in series, and (2) a current commutation component composed of diodes VD1-VD4, a current injection branch and a current commutation branch. VD1-VD4 are used for conducting bidirectional current; the current injection branch comprises a pre-charging capacitor C, an inductor L and a thyristor T which are connected in series; the current commutation branch circuit is formed by connecting a power electronic switch, an RCD buffer branch circuit and an energy absorption branch circuit in parallel, and the energy absorption branch circuit is composed of a metal oxide lightning arrester; the invention further discloses a current breaking method of the superconducting hybrid direct-current circuit breaker. According to the invention, quick switching-off can be realized after fault current occurs, the rise rate of the fault current is limited, and the loss and the cost are low under the normal through-current condition.

The invention belongs to the technical field of direct-current power transmission, and discloses an IGCT assembly structure for a converter valve, and the structure comprises a valve assembly and a press-fitting part which is used for carrying out the press-fitting and fixing of the valve assembly. The valve assembly comprises n IGCT devices, n + 1 water-cooled radiators, 2n static voltage-sharing resistors, n lightning arresters and 4n damping resistors. The n IGCT devices and the (n + 1) water-cooled radiators are arranged in a stacked manner; the 2n static voltage-sharing resistors and the 4n damping resistors are arranged on the water-cooling radiator; and each lightning arrester is connected with the water-cooled radiator through the first connecting busbar. According to the valve assembly, the IGCT device is used, the problem of commutation failure of the direct-current power transmission technology is solved, meanwhile, the IGCT device is a full-control device, control over switching-on and switching-off is achieved, when a direct-current system breaks down, the valve assembly can also be used as a direct-current circuit breaker, and controllability is high; devices of the valve assembly are distributed on the water-cooling radiator, and the heat dissipation function of the water-cooling radiator is fully utilized.