77 results about "Fault current limiting" patented technology

The invention discloses a converter collaborative current limiting method based on adaptive virtual impedance and a power loop, and the method comprises the steps: firstly building an equivalent impedance model of a converter and a power grid, analyzing the steady-state and transient characteristics of fault current, and extracting key parameters for current limiting design; when it is detected that the voltage drop of the grid-connected point exceeds a threshold value, a self-adaptive virtual impedance link is automatically put into use, and virtual resistance and reactance values are dynamically calculated according to the variation amplitude of voltage or current, so that the virtual resistance and reactance values are proportionally adjusted along with the fault degree; and when the system voltage returns to normal, the virtual impedance automatically quits, and the control continuity is ensured. Then, the active and reactive power reference values are dynamically corrected according to the voltage drop depth, a power reference signal matched with the voltage amplitude is generated, it is guaranteed that power output does not exceed the limit, and the voltage supporting capacity is improved. Finally, real-time current-limiting control of the converter and stable operation of the system are realized on the premise of not switching the control mode through the synergistic effect of the virtual impedance ring and the power ring. The method has the advantages of being high in response speed, excellent in current limiting effect, good in control continuity and the like, and is suitable for fault current limiting and voltage support control of the grid-forming converter.

The invention discloses a time sequence fault current-limiting control method and system compatible with a grid-connected guide rule for a network construction type doubly-fed wind turbine generator, and the method comprises the following steps: freezing external power control when a low-voltage ride-through event of a power grid is detected at the initial stage of a fault, and suppressing transient overcurrent through dynamically adjusting the resistance component of virtual impedance; in the fault stable stage, an electromotive force compensation increment is calculated on the basis of grid-connected guide rule requirements at the moment 4 tau after the fault occurs; in the fault clearing stage, after it is detected that the fault is cleared, electromotive force compensation is stopped; gradually recovering the virtual impedance to a rated value through the dynamic coefficient A; in the fault recovery stage, active control and reactive control are recovered in sequence, power output is recovered to the level before the fault within one second, and meanwhile the virtual impedance amplitude is gradually recovered to the rated value along with the voltage phase difference; the voltage phase jump amplitude and the voltage drop amplitude determined by the method have high robustness.

The invention provides a network construction current limiting method, network construction type converter equipment and a new energy system, and relates to the technical field of new energy. The method comprises the following steps: in response to a condition that a power grid signal meets a preset condition, determining that network-forming converter equipment enters a current-limiting mode, and determining virtual impedance of a first stage of the current-limiting mode; determining that the network construction type converter equipment is in a first stage, and controlling the network construction type converter equipment by using the virtual impedance; and determining that the network construction type converter equipment is in a second stage of the current limiting mode, adjusting the virtual impedance according to the power grid signal, and controlling the network construction type converter equipment by using the adjusted virtual impedance. According to the embodiment of the invention, the current limiting mode of the network-forming converter equipment is divided into the first stage and the second stage, and the virtual impedance of the first stage is adjusted in the second stage, so that fault current limitation and power grid voltage support can be considered at the same time.

The invention discloses an adaptive virtual impedance-based fault current limiting method for a network-forming converter, and belongs to the technical field of converter control. Comprising the following steps: collecting grid-side voltage, converter-side voltage and converter output current; carrying out current amplitude calculation on the grid-side voltage quantity to obtain a current effective value of the port of the converter; judging whether the current effective value of the current transformer port exceeds a current threshold value of the current transformer; and if yes, self-adaptive virtual impedance is introduced to carry out converter fault current limitation. The resistance part of the virtual impedance is used for suppressing surge current at the beginning of a fault; and the reactance part is used for suppressing the effective value of the fault transient current within the current limiting range. In the fault process, the current virtual impedance value is adaptively changed according to the effective value of the current overcurrent, and the virtual impedance can be automatically quitted after the fault end stage. The method is suitable for fault current suppression of the network-forming converter in various control modes, and has good feasibility and practical value.

The invention provides a zero-loss deep current limiting device and a current limiting device control method, and relates to the technical field of transformer fault current limiting, the device comprises a main switch branch, an energy absorption branch, an artificial zero-crossing branch and a current limiting reactor; the main switch branch comprises a vacuum type quick switch which is positioned between the bus and the main transformer high-voltage winding connecting end part; the artificial zero-crossing branch and the modulation inductor are connected in series and then are connected in parallel to the main switch branch; the artificial zero-crossing branch comprises a zero-crossing energy storage capacitor and a vacuum trigger switch, and the zero-crossing energy storage capacitor and the vacuum trigger switch are connected in series; the current limiting reactor is connected in parallel to the vacuum type quick switch; and a controller for controlling the vacuum trigger switch and the vacuum type quick switch to work is also arranged in the device. The energy absorption branch comprises a zinc oxide resistor which is connected in parallel with the artificial zero-crossing branch. The current limiting reactor is small in loss in the normal running state of the system and high in running reliability when the system breaks down.

The invention discloses an inverter transient stability method and system based on adaptive phase compensation, belongs to the technical field of grid-connected inverter control, and aims to solve the contradiction between fault current limiting and transient stability in the prior art. According to the invention, a phase compensation coefficient for self-adaptively adjusting according to the real-time power grid voltage and the change rate thereof is introduced into the synchronous loop of the virtual synchronous generator, and the coefficient can dynamically optimize the equivalent active power reference, the equivalent inertia and the damping of the system and cooperate with the voltage feedback of the reactive loop, so that the real-time performance of the system is improved. Therefore, the stability margin of the system is effectively expanded during the power grid fault period. On the premise of not sacrificing the fault current limiting capability, the transient stability and the fault ride-through capability of the inverter are remarkably enhanced, power and frequency oscillation is effectively inhibited, collaborative optimization of multiple performance indexes is realized, and the method has the advantages of simple structure and high robustness.

The invention discloses a network construction type converter fault current limiting method considering power angle stability, and belongs to the power electronic technology. According to the method, firstly, an active power adaptive adjustment coefficient is introduced into an active-frequency control loop, the power angle variation of the converter at the moment of a fault is suppressed, and the transient power angle stability of the converter is guaranteed; secondly, an output voltage reference value is adjusted through a reactive power-voltage control loop, the voltage difference between the converter and the power grid is reduced, and the current steady-state component in the fault period is restrained; and finally, a variable virtual reactance is introduced into a voltage outer ring, and a transient current impact component at the fault moment is suppressed. The current limiting method is provided for the grid-forming type converter when the grid-side voltage symmetrically drops, continuous increase of the output current in the converter fault period can be restrained, meanwhile, power angle instability is prevented, and the method has the advantages of being high in response speed, good in current limiting effect and high in power angle stability.

The invention provides a self-adaptive short-circuit fault current-limiting control method and system for a primary and secondary fusion circuit breaker, and relates to the technical field of circuit protection and manufacturing, and the method comprises the steps: collecting a current value, a voltage value and a state quantity of a circuit breaker, and forming a first operation parameter set; performing feature extraction based on the amplitude abrupt change, the phase offset and the harmonic component, generating a first feature vector, and matching the first feature vector with a preset short-circuit fault feature template to obtain a fault recognition result, a fault type and a position identifier; a dynamic current-limiting control curve is calculated according to the identifier and the current value, a current-limiting control parameter set is generated, and a current-limiting execution mechanism is controlled to obtain current-limiting response data; after the action is completed, a second operation parameter set is collected, current limiting effect analysis is executed to generate state feedback data, and a current limiting control parameter set is updated based on the feedback data; and factory calibration can be carried out on the power electronic current limiting module serving as a current limiting execution mechanism. According to the method, the adaptive capacity and accuracy of current limiting control are improved.

This invention relates to the field of power distribution network technology and discloses a direct-connected integrated energy storage-power flow conversion device and its control method. It employs a direct-connected multi-module series-parallel composite topology, organically integrating multiple functions—power flow conversion module, energy storage module, voltage support and current limiting module—into a single device. Based on a hierarchical coordinated control architecture designed for the three functional circuits, it achieves flexible and precise control of power flow between the two-terminal grids and efficient coordinated management of the energy storage units within the device. It also provides active voltage support and transient fault current limiting protection for the sending-end grid. This integrated design significantly reduces equipment redundancy, simplifies the overall system architecture, and, through the internal coordinated control of each functional module, significantly improves the device's operational reliability under complex conditions such as power flow reversal, load surges, and transient faults.

The present application relates to the field of high-voltage direct current transmission, and aims to provide a topology of bridge arm integrated current-limiting energy-consuming device, a converter valve and a coordinated control method. The topology is a modular MMC architecture of three-phase double bridge arms, which comprises a plurality of MMC sub-modules connected in series in the upper bridge arm, and a current-limiting energy-consuming device composed of a plurality of current-limiting energy-consuming sub-modules connected in series in the lower bridge arm; the current-limiting energy-consuming sub-module comprises a sub-module main power unit and a sub-condition energy-consuming unit, the latter at least contains two energy-consuming units adapted to different fault conditions, and each contains an energy-consuming resistor and an adaptive condition switching device. The present application integrates the functions of direct-current fault current limiting and alternating-current fault energy consumption in the same integrated device, realizes integrated protection of AC and DC faults, does not need to configure multiple sets of separate equipment, and solves the problem of functional redundancy of the traditional scheme. Redundant configuration can be reduced, hardware cost is reduced, system size is reduced, and operation and maintenance complexity is simplified; the risk of device overvoltage breakdown is avoided, and the service life of the equipment is improved.

The invention provides an adjusting method and system for a network construction converter, electronic equipment and a storage medium, and the method comprises the steps: switching the network construction converter from a droop control mode to a fault current limiting mode under the condition of a network fault of the network construction converter; under the condition that the network construction converter network is in the fault current limiting mode, the control of a voltage loop of the network construction converter network fails, and the maximum current amplitude allowed to flow through by the network construction converter and the output value of the voltage loop are determined; and obtaining a current loop reference value according to the maximum current amplitude and the output value of the voltage loop. Rapid fault recovery of the network construction converter can be realized, the network construction converter is prevented from being locked in a current limiting mode after the fault is removed, and the transient stability of the network construction converter is improved.

A Solid-State Circuit Breaker Device and Method Without Current Limiting Inductor. According to an exemplary embodiment of this disclosure, described is a high-density, high-efficiency megawatt (MW) medium-voltage (MV) solid-state circuit breaker (SSCB) for, example only, aviation hybrid electric propulsion applications. The SSCB is based on the mature silicon (Si) insulated gate bipolar transistor (IGBT) devices. With reduced IGBT gate voltage, the disclosed SSCB can limit the peak fault current without the fault current limiting inductor. Thus, the specific power density of the SSCB is substantially improved compared with the traditional design.

Systems and methods for transferring a load between power sources may include monitoring voltage waveforms of power sources, in response to a power quality event affecting a first power source, switching a first switch device off to disconnect the load from the first power source, calculating a phase angle difference between the power sources based on the monitored voltage waveforms, selecting one of a first and second algorithms for transferring the load to a second power source based on the phase angle, selectively switching a second switch device using the selected one of the first algorithm and the second algorithm to transfer the load to the second power source. A controller may select the one of the first algorithm and the second algorithm based on the phase angle and a metric of the load transfer associated with the algorithms.

The invention relates to a low-voltage intelligent circuit breaker fault condition test and evaluation method and system based on a deep neural network. The method comprises the following steps: collecting real-time operation data of a low-voltage intelligent circuit breaker; performing normalization, denoising and feature extraction on the collected real-time operation data of the low-voltage intelligent circuit breaker in sequence; constructing an overcurrent control circuit for executing a fault current limiting (FCL) function; based on the extracted features, a complete protection closed loop from detection, current limiting, isolation to recovery is realized by using a constructed overcurrent control circuit for executing an FCL function; based on the fault record characteristics and the equipment operation state parameters, intelligent fault current detection is carried out by using a deep neural network method to obtain fault data so as to realize an FCL function; and designing heat capacity based on the system thermal resistance parameter and the fault current parameter, and obtaining a low-voltage intelligent circuit breaker fault condition test evaluation result based on thermal performance through thermal simulation and transient modeling. According to the invention, the performance and reliability of the system under the actual fault condition can be predicted and evaluated.

This application provides a VSG fault current limiting control strategy based on reactive power deviation integral feedback, including: constructing a reactive power deviation integral feedback control branch between the reactive power droop control output and the voltage command generation in the VSG reactive power loop; determining an integral feedback compensation value based on reactive power deviation control based on the reactive power deviation integral feedback control branch; and limiting the short-circuit current amplitude based on the integral feedback compensation value. The strategy proposed in this application, by introducing reactive power deviation integral feedback compensation control during fault periods, can equivalently adjust the reactive power droop coefficient and voltage command value, effectively reducing the fault current amplitude during fault periods and providing reactive power support for the system.

1. Name of the product in this design: Current-limiting reactor. 2. Purpose of this design: To limit excessively rapid fault current. 3. The key design feature of this product is its shape. 4. The image or photograph that best illustrates the design's key points: 3D view 1.

The invention provides a transformer short-circuit fault current limiting device and a capacitor maintenance management method in the device. The transformer short-circuit fault current limiting device comprises a main branch, a current limiting branch, a modulation inductor, an artificial zero-crossing branch and an energy consumption detection branch. The main branch is provided with a vacuum quick switch which is connected in series between the bus and the primary side port of the transformer; the current-limiting branch is provided with a current-limiting reactor which is connected in parallel with the vacuum quick switch. The artificial zero-crossing branch is connected in series with the modulation inductor and then is connected in parallel with the current-limiting branch, and the artificial zero-crossing branch comprises an energy-storage capacitor bank module and a vacuum trigger switch which are connected in series. In the application, when the fault current on the main branch is detected, the vacuum quick switch is firstly controlled to be switched off, and then the vacuum trigger switch is controlled to be switched on, so that the vacuum quick switch can be switched on and off conveniently; furthermore, the vacuum trigger switch is controlled to be turned off, the current limiting reactor is connected between the power distribution system bus and the transformer, short-circuit fault current limiting is achieved, and damage to the transformer when the load is short-circuited is reduced.

The invention provides a partial-capacity medium-voltage flexible interconnection device and a fault current-limiting control method, and belongs to the technical field of medium-voltage power distribution network flexible interconnection, and the device comprises a power frequency isolation transformer, a power flow transfer module, a fault protection module, and a fault current-limiting module formed by connecting a diode rectifier bridge and a thyristor in parallel. During normal operation, the power frequency isolation transformer provides isolation to ensure that the power flow transfer module does not cause loss due to generation of leakage current, and meanwhile, a thyristor SCR1A of the fault protection module is turned off to ensure normal power flow adjustment of the series converter module; when a power grid line breaks down, devices of the series module are all locked, meanwhile, the thyristor SCR1A is rapidly switched on so as to bypass the series module, the thyristor SCR2A of the fault current limiting module is switched off, and the diode rectifier bridge is connected to the line in series and blocks fault current. The device overcomes the defects that a traditional device is high in cost and needs complex protection, gives consideration to efficiency and compactness, and is suitable for low-cost flexible power flow control of the medium-voltage power distribution network.

The present application relates to the technical field of grid-forming converter control, and particularly relates to a grid-forming converter fault ride-through method and system based on dynamic virtual resistance control, which comprises the following steps: adding a control link based on virtual impedance in a grid-forming converter control system; detecting the actual value of grid voltage to determine whether the grid voltage drops; detecting the current amplitude output by the grid-forming converter in real time to determine whether the current amplitude exceeds a set value; if one of the two conditions is met, starting the virtual impedance control link: performing stage-type current limiting control on the virtual resistance, and the size of the virtual resistance provided by the grid-forming converter to the power system is adjusted in real time according to the fault current amplitude; when the grid voltage recovers and the current amplitude is less than the set value, the stage-type current limiting control of the virtual resistance is exited. The present application can realize fault current limiting during grid-forming converter fault ride-through, thereby improving the fault ride-through capability and transient stability performance of the grid-forming converter.

The application relates to the technical field of power distribution networks, and discloses a novel DC power distribution network hybrid current limiter and a polarity self-recovery control method, wherein the hybrid current limiter comprises: hybrid current limiters which are respectively arranged in series between current limiters and DC circuit breakers at two ends of a DC line, and each end hybrid current limiter comprises a current passing branch, a current limiting branch and a commutation branch; the current passing branch is used for providing a current passing path; the current limiting branch is used for limiting the increase of a fault current; and the commutation branch is used for performing current commutation of the current passing branch and the current limiting branch to block the passing of the fault current from the current passing branch; the application not only improves the fault current limiting capacity of the DC power distribution network, but also reduces the breaking stress of the DC circuit breaker and the investment cost of the DC power distribution network system, and realizes fast reclosing.

The application provides a VSG fault whole-process multi-target ride-through control strategy, which comprises the following steps: closing the second switch to a preset first side to establish a first side passage connection; monitoring and judging whether the closing trigger condition of the first switch is met in real time; if yes, closing the first switch and outputting a first target power angle value; when detecting that the power grid fault is removed, closing the second switch to a preset second side and outputting a second target power angle value; and disconnecting the first switch after the VSG restores to stability. The strategy provided by the application realizes the multi-target fault ride-through of the VSG from the regulation and control requirements of the transient synchronization stability of the VSG, fault current limiting, impact current suppression, fault rapid recovery and power support.

The application discloses a rotary liquid metal current limiter. The limiter comprises an insulating shell, a first electrode, a second electrode, a rotating mechanism, liquid metal and a driving device. The insulating shell forms an accommodating space inside, and the two electrodes are respectively arranged on opposite two side walls of the insulating shell and partially located in the accommodating space. The rotating mechanism is composed of a rotating shaft and at least one rotating blade with a through-flow hole. The rotating shaft is rotatably installed on the insulating shell, and the rotating blade is fixed on the rotating shaft. In normal operation, the liquid metal forms a conductive path between the two electrodes through the through-flow hole. The driving device is connected with the rotating shaft. When a short-circuit current is detected, the rotating shaft is driven to rotate, the relative position of the through-flow hole and the electrode is changed, and the resistance of the conductive path of the liquid metal is changed. In normal operation, the high rated current-carrying capacity is ensured by the through-flow hole. When a short circuit occurs, the through-flow hole position is changed by the rotating blade to realize rapid current limiting, and the rated current-carrying capacity and the fault current limiting performance are effectively balanced.

The application discloses an improved VSG control method suitable for transient power angle suppression and voltage support, and the method comprises the following steps: obtaining a power angle reference value δ* and an internal potential reference value E*, and generating a reference voltage of VSG control; wherein the power angle reference value δ* is obtained by using a P-f control link according to an active power given value P e 0, an active electromagnetic power P e 0 and an angular frequency rated value ω0; the internal potential reference value E* is obtained by using a Q-U control link according to a reactive power given value Q0, a reactive electromagnetic power Q t 0 and a voltage rated value E0; if a voltage sag fault occurs in a power grid, at least one of scheme one and scheme two is used; wherein the scheme one comprises inputting a virtual resistance feedback link to the P-f control link to realize power angle compensation; the scheme two comprises inputting a virtual capacitor feedback link to the Q-U control link to realize output voltage compensation. The application can suppress power angle divergence and improve voltage support capability under the condition of considering fault current limiting.

The application is suitable for the technical field of converter control, and provides a network type converter transient and steady state promotion control method based on current latch inhibition, equipment and medium, the method comprises the following steps: in the whole process of power grid fault current limiting and fault recovery, the internal voltage source active power of the network type converter is used as a closed loop feedback quantity to carry out power synchronous closed loop regulation, continuously output angular frequency and voltage reference instruction, and continuously adjust virtual power angle; when it is detected that the power grid fault is cleared, the current real-time virtual power angle is latched as the initial virtual power angle of fault recovery, and the current voltage reference instruction is combined to continuously update the current reference instruction; the virtual power angle, the internal voltage source active power, the current reference amplitude and the grid-connected point voltage are monitored in real time, and when all state variables converge to the steady state interval corresponding to normal operation, the network type converter is automatically controlled to exit current limiting, the current latch problem is effectively solved, and the transient and steady state operation performance of the network type converter is improved.

A circuit breaker network includes a solid-state circuit breaker (SSCB), one or more circuit breakers, and a current limiting control circuit of the SSCB. The current limiting control circuit is programmed to determine a first time period for keeping the SSCB in an on state, determine a second time period for keeping the SSCB in an off state, and switch, cyclically, the SSCB to the off state for the second time period and then to the on state for the first time period to control the fault current within a predetermined band-to-band range that is below the first current threshold and above the second current threshold for a fault clearance duration.

The invention discloses a single-core step-down phase shifter based on thyristor control and a winding transformation ratio design and multi-mode control method thereof, and the maximum utilization of the winding capacity of the phase shifter and the minimum adjustment step length in the adjustment process are realized through the transformation ratio design of a secondary winding of the phase shifter; when no fault is detected, the transformation ratio of the winding is controlled through the thyristor valve group so as to execute voltage reduction and phase shift operation, the output voltage amplitude and the phase shift angle are kept at reference values, and the system runs normally; after a fault occurs, impedance is calculated, and the fault position is determined; when an upstream fault occurs, entering a low-voltage protection mode, and limiting a non-fault phase-to-ground voltage through a phase shifter winding; and when a downstream fault occurs, entering a fault current limiting mode, and compensating voltage and absorbing power through a phase shifter winding so as to limit fault phase current and maintain non-fault phase voltage. According to the invention, the functions of voltage stabilization during normal operation of the phase shifter, low-voltage protection during abrupt drop of upstream voltage and current limiting during a downstream short-circuit fault can be realized.

The invention relates to a VSG power current cooperative control method, system and device based on an improved SOGI under an unbalanced power grid and a medium, and the method comprises the steps: constructing a VSG control mathematical model, and carrying out the calculation to obtain the instantaneous active power and reactive power provided by a VSG; performing positive and negative sequence separation by adopting an improved SOGI to obtain a positive sequence component and a negative sequence component of voltage and current; during the normal operation state of the system, performing sequence-dividing control of the VSG under the voltage and current double closed loop based on the positive sequence component and the negative sequence component of the voltage and current; during a system fault period, a correlation coefficient is introduced to realize cooperative control of VSG output power constancy and grid-connected current balance, a negative sequence current instruction is obtained through calculation, and virtual impedance is introduced to carry out fault current limiting and carry out positive sequence current instruction calculation under a voltage outer loop. And realizing system stability according to the positive sequence current instruction, the negative sequence current instruction and the reactive power support. The method can be widely applied to the technical field of virtual synchronous generator control.

The invention belongs to the field of micro-grid fault current-limiting control, and particularly relates to a VSG self-adaptive supplementary control method based on virtual impedance current limiting for grid-connected and island micro-grids, which comprises the following steps of: S1, analyzing active and reactive loops of a VSG in a distributed power supply control structure, and deducing a reference voltage expression; s2, generating a reference current through a proportional resonance controller, and protecting the inverter from an overcurrent problem by adopting an anti-saturation technology; s3, proposing a sine reference current limiting method based on peak detection, and limiting the reference current within a threshold value by using a reduction factor; and S4, providing a reference voltage correction method based on adaptive virtual impedance, and reducing a voltage tracking error by using the virtual impedance and an adaptive term. According to the VSG self-adaptive supplementary control method based on virtual impedance current limiting, the voltage tracking error can be reduced, saturation of a voltage controller is avoided, the good fault current limiting effect is achieved, and the important practical value is achieved for micro-grid fault current limiting control.

The application provides a fault current limiting system suitable for an over-configuration network type energy storage system, which comprises: a voltage loop connected with an energy storage unit; a current limiter connected with the voltage loop; the current limiter has an asymmetric limiting boundary, that is, the maximum allowable values of d-axis and q-axis currents in a current d-q coordinate system are different; and a current loop connected with the current limiter and a power grid. The application can realize differentiated constraints of AC side reactive current and DC side active current, and improve the voltage support capability and low voltage ride through performance of the system.

The invention provides a zero-loss current limiting device based on an artificial zero-crossing technology and a device monitoring and maintenance method, and relates to a transformer fault current limiting technology, the device comprises a main switch branch, an energy absorption branch and an artificial zero-crossing branch; the main switch branch comprises a vacuum fast switch, the vacuum fast switch is connected in series between a bus of the power distribution system and the input end of the main transformer, and the vacuum fast switch is connected in parallel with a current limiting reactor; a modulation inductor is connected in series between the main switch branch and the artificial zero-crossing branch, and the energy absorption branch is connected in parallel to the artificial zero-crossing branch; the energy absorption branch comprises a plurality of zinc oxide resistors, and a nonlinear resistor module is formed by the plurality of zinc oxide resistors; the artificial zero-crossing branch comprises an energy storage unit and a trigger switch, the energy storage unit at least comprises a zero-crossing energy storage capacitor, and the zero-crossing energy storage capacitor and the trigger switch are connected in series. The zero-crossing energy storage capacitor releases electric energy to artificially produce a zero-crossing point, so that rapid opening of the vacuum rapid switch is facilitated, and short-circuit fault current limiting is realized.