Method and system suitable for recovery and re-operation after fault of source network load storage system

Abstract

The invention, which relates to the technical field of flexible interconnection power distribution, discloses a post-fault recovery and re-operation method and system suitable for a source network load storage system, and the method comprises the steps: detecting whether a fault occurs in the system; when the system breaks down, a specific fault reason is judged; different measures are taken according to different fault reasons. By recovering the system after the fault, the system can quickly recover normal operation when the fault occurs, the downtime caused by the fault is reduced, and the continuous power supply capability of the system is enhanced. In the fault recovery process, the change rate of current and power is limited, system overcurrent impact caused by improper control strategies is avoided, power electronic devices are protected, and the service life of equipment is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible interconnected power distribution, and specifically to a post-fault recovery and re-operation method and system applicable to a source-grid-load-storage system. Background Art

[0002] Energy storage technology can smooth power fluctuations, reduce peaks and fill valleys, improve power quality, and enhance the grid's ability to absorb new energy by transferring energy at the time level. It is an effective solution to deal with the grid connection of new energy. Energy storage systems based on power electronic devices have attracted widespread attention for their advantages such as fast response speed and large capacity expansion. Fast-responding large-capacity energy storage systems can be used as energy buffers to decouple power generation and power consumption at the time level, enhance the self-regulation ability of regional distribution networks, improve power transmission and transformation capabilities, and solve cross-regional supply and demand contradictions. Cascaded H-bridge chain battery energy storage system (CHB-ESS) has been widely studied for its advantages of "split control", high efficiency, reliability, modularization, and easy expansion. However, limited by the radial architecture of traditional distribution networks, large-capacity energy storage currently adopts a chain power conversion topology with a single medium-voltage AC port, which is distributed and connected to different distribution networks. The distributed access solution faces problems such as large battery capacity, low system utilization, high cost, and large floor space.

[0003] In addition to energy storage technology, flexible interconnection technology can also realize the transfer of energy flow at the spatial level, solving problems such as flow congestion, node voltage exceeding the limit, and insufficient system stability caused by the access of new energy and new loads. When the distribution network is operating normally, the flexible interconnection equipment provides continuous active regulation and reactive power support to achieve load balancing and congestion relief, and improve voltage quality; when the distribution network fails, it provides fault isolation, flow transfer and power supply restoration functions. Although flexible interconnection technology has been applied in some medium-voltage distribution projects, its large-scale promotion faces two major challenges: first, it is constrained by the state of the power grid, the regulation capacity is limited, and there is a lack of time transfer capability for energy flow; second, the existing flexible interconnection equipment needs to add a full-power structure when expanding the port, which faces the problems of high cost and large volume.

[0004] In view of the advantages and disadvantages of the two solutions, some scholars have proposed a chain battery energy storage power conversion system (multiple-AC-ports cascaded H-bridge energy storage system, MACP-CHB-ESS) with multiple medium-voltage AC ports by adding a small-power half-bridge module based on the existing single AC port CHB-ESS structure and integrating the advantages of flexible interconnection technology. It has multiple AC feeders connected to the same CHB-ESS, which can realize the interconnection and energy storage sharing between AC power grids in different regions, which is conducive to improving the utilization rate of energy storage systems and optimizing system flow operation. However, there is still a lack of research on the fault protection system of MACP-CHB-ESS at home and abroad, and it is urgent to propose a fault protection scheme suitable for a new source-grid-load-storage system. Therefore, the present invention proposes a post-fault recovery and re-operation technology suitable for source-grid-load-storage systems. When a short-circuit fault occurs, it can not only effectively protect the MACP-CHB-ESS, but also achieve rapid recovery of the device and the line after removing the faulty line. Summary of the invention

[0005] In view of the above-mentioned problems, the present invention is proposed.

[0006] Therefore, the technical problem solved by the present invention is: the technical problems faced by flexible interconnection technology in large-scale promotion, such as limited adjustment capability and high cost of port expansion.

[0007] In order to solve the above technical problems, the present invention provides the following technical solution: a method for recovering and re-operating a source-grid-load-storage system after a fault, which comprises the following steps:

[0008] Detect whether the system has any faults; when the system has any faults, determine the specific cause of the fault; take different measures according to different causes of the fault.

[0009] As a preferred solution of the post-fault recovery and re-operation method applicable to the source-grid-load-storage system described in the present invention, when a fault occurs, safety protection measures are immediately initiated.

[0010] As a preferred solution of the post-fault recovery and re-operation method applicable to the source-grid-load-storage system described in the present invention, when a system failure occurs, the device is safely switched over through the TBS bypass, and is put back into operation after the fault is isolated to restore the charging, discharging and power flow regulation functions of the MACP-CHB-ESS.

[0011] As a preferred solution of the post-fault recovery and re-operation method applicable to the source-grid-load-storage system described in the present invention, the specific fault causes include the fault of the balanced feeder and the fault of the unbalanced feeder.

[0012] As a preferred solution of the post-fault recovery and re-operation method applicable to the source-grid-load-storage system described in the present invention, the taking of different measures includes, when a balanced feeder fault occurs, activating the lower switch tube of the half-bridge submodule in the TBS bypass PFCM and immediately locking all half-bridge submodules.

[0013] When the TBS is activated, it quickly locks the CHB-ESS, reducing the current in the parallel branch to zero, and simultaneously, upon detecting a fault, sends a trip signal to the circuit breaker at the fault port of the device, causing the circuit breaker to cut off the connection with the faulty feeder.

[0014] As a preferred scheme of the post-fault recovery and re-operation method applicable to the source-grid-load-storage system described in the present invention, when a balanced feeder failure occurs, the control system also includes, after the balanced feeder failure occurs, reselecting one of the remaining normally operating feeders as the balanced feeder and performing control switching.

[0015] The control switching includes phase-locked loop input switching and port control mode switching, wherein the phase-locked loop input of the system is switched from the three-phase voltage at the original balanced feeder interconnection port to the three-phase voltage at the new balanced feeder interconnection port, the interconnection port control mode of the MACP-CHB-ESS connected to the new balanced feeder is switched, the active command value is determined by the CHB-ESS charging and discharging power, the reactive power is controlled by the reactive component of the CHB-ESS output current, and at the TBS locking moment, the inputs of the CHB-ESS voltage outer loop PI controller and the current inner loop PI controller are set to zero, and the PI controller output before locking is maintained.

[0016] After waiting for the circuit breaker at the MACP-CHB-ESS interconnection port outlet to trip, the fault isolation is completed, and its control is first restored, the PI controller input of the voltage outer loop and the current inner loop is canceled and set to zero, and the new CHB-ESS current reference value is switched according to the given conversion rate.

[0017] After the control of CHB-ESS is restored, the PI controller is reset to restore the initial state before the power flow control loop is put into use again. At the same time, when the feeder power flow and current instructions are given, the change rate is limited. At the same time, the PFCM DC bus voltage control is restored to stabilize the PFCM DC bus voltage at the set value.

[0018] As a preferred solution of the post-fault recovery and re-operation method applicable to the source-grid-load-storage system described in the present invention, the taking of different measures also includes that when an unbalanced feeder fault occurs in the system, the interconnected ports of MACP-CHB-ESS maintain the original control mode without switching.

[0019] Another object of the present invention is to provide a post-fault recovery and re-operation system suitable for a source-grid-load-storage system, which can solve the problem of slow response and easy secondary impact of the existing system during fault recovery by quickly resetting and optimizing control strategies.

[0020] To solve the above technical problems, the present invention provides the following technical solution: a post-fault recovery and re-operation system applicable to a source-grid-load-storage system, comprising a cascaded full-bridge submodule, a half-bridge submodule and a power flow control module.

[0021] The cascaded full-bridge submodule is composed of two parallel-connected half-bridge submodules and is used for integration into a medium voltage AC port.

[0022] The half-bridge submodule is used to expand the number of AC ports of the system.

[0023] The power flow control module is a main loop consisting of FBSM and a newly added HBSM, which is responsible for controlling the power flow and maintaining the energy balance within the system.

[0024] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the steps of the post-failure recovery and re-operation method applicable to a source-grid-load-storage system as described above are implemented.

[0025] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the post-failure recovery and re-operation method applicable to a source-grid-load-storage system as described above.

[0026] Beneficial effects of the present invention: By restoring and re-running the system after a fault, the present invention can ensure that the system can quickly resume normal operation when a fault occurs, reduce downtime caused by the fault, and enhance the continuous power supply capability of the system. During the fault recovery process, the present invention limits the rate of change of current and power, avoids system overcurrent shocks caused by improper control strategies, protects power electronic devices, and prolongs the service life of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0028] Figure 1 This is an overall flow chart of a method for post-failure recovery and re-operation of a source-grid-load-storage system provided in the first embodiment of the present invention.

[0029] Figure 2A schematic diagram of the topological structure of a chain battery energy storage power conversion system with multiple medium voltage AC ports in a method for post-fault recovery and re-operation of a source-grid-load-storage system provided in the first embodiment of the present invention.

[0030] Figure 3 The first embodiment of the present invention provides a chain battery energy storage power conversion system isolation protection scheme for multiple medium voltage AC ports in a method for post-fault recovery and re-operation of a source-grid-load-storage system.

[0031] Figure 4 This is an overall framework diagram of a post-fault recovery and re-operation system applicable to a source-grid-load-storage system provided in accordance with a second embodiment of the present invention.

[0032] Figure 5 The current waveform of the feeder 1 connected to the chain battery energy storage power conversion system with multiple medium voltage AC ports in the post-fault recovery and re-operation method applicable to the source-grid-load-storage system provided in the third embodiment of the present invention.

[0033] Figure 6 The current waveform of the feeder 2 connected to the chain battery energy storage power conversion system with multiple medium voltage AC ports in the post-fault recovery and re-operation method applicable to the source-grid-load-storage system provided in the third embodiment of the present invention.

[0034] Figure 7 The current waveform of the feeder 3 connected to the chain battery energy storage power conversion system with multiple medium voltage AC ports in the post-fault recovery and re-operation method applicable to the source-grid-load-storage system provided in the third embodiment of the present invention.

[0035] Figure 8 The current waveform of the chain battery energy storage power conversion system CHB-ESS with multiple medium voltage AC ports in the post-fault recovery and re-operation method of the source-grid-load-storage system provided in the third embodiment of the present invention is applicable.

[0036] Fig. 9 The DC bus voltage of the chain battery energy storage power conversion system PFCM with multiple medium voltage AC ports in the post-fault recovery and re-operation method for the source-grid-load-storage system provided in the third embodiment of the present invention.

[0037] Fig.10 The third embodiment of the present invention provides a feeder flow connected to a chain battery energy storage power conversion system with multiple medium voltage AC ports in a method for post-fault recovery and re-operation of a source-grid-load-storage system. DETAILED DESCRIPTION

[0038] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0039] Example 1, reference Figure 1 to Figure 3 , is an embodiment of the present invention, and provides a method for post-failure recovery and re-operation of a source-grid-load-storage system, which is characterized by:

[0040] The present invention is based on the document "Multi-medium voltage AC port chain battery energy storage power conversion system". The MACP-CHB-ESS topology is derived from the traditional cascaded H-bridge energy storage system (cascaded H-bridge energy storage system, CHB-ESS), which is achieved by integrating a cascaded full bridge sub-module (FBSM) at the medium voltage AC port. The FBSM consists of two parallel half bridge sub-modules (HBSM), one of which is connected to the feeder and the other is connected to the next sub-module of the CHB-ESS. By connecting additional HBSMs in parallel on the DC side of the FBSM, the number of medium voltage AC ports can be expanded, thereby constructing a MACP-CHB-ESS system with multiple AC ports.

[0041] The main loop consisting of FBSM and the newly added HBSM is defined as a power flow control module (PFCM). Among them, the HBSM connected to the feeder is responsible for regulating the power flow between the feeders and controlling the charging and discharging process of the energy storage system. This part is called the power flow regulation half bridge. The HBSM connected to the CHB-ESS focuses on maintaining the DC bus voltage stability of the PFCM and ensuring the energy balance within the system. This part is called the balance regulation half bridge. Figure 2-Figure 3 shown.

[0042] S1: Check whether the system fails.

[0043] Once a system fault is detected, safety protection measures are immediately initiated to ensure that power electronic devices respond quickly.

[0044] S2: When a system failure occurs, determine the specific cause of the failure.

[0045] The specific fault causes include balanced feeder failure and unbalanced feeder failure.

[0046] S3: Take different measures according to different fault causes.

[0047] When a short circuit occurs in the feeder, the lower switch tube of the half-bridge submodule in the PFCM is bypassed by activating the TBS, and all half-bridge submodules are immediately locked to prevent the DC bus from short circuiting. The activation of TBS limits the output voltage of the PFCM to close to 0V, effectively blocking the power exchange between the AC feeder and the PFCM DC bus. At the same time, the current is shunted through the TBS branch, reducing the overcurrent burden on the IGBT, thereby protecting the IGBT from damage.

[0048] In order to prevent the output current of the parallel CHB-ESS from affecting the short-circuit current distribution of the energy storage sharing flexible interconnection system and increase the complexity of the protection design of the AC feeder area, when the TBS is activated, the CHB-ESS will also lock quickly to reduce the current of the parallel branch to zero. In addition, in order to avoid the failure of the AC feeder area protection, causing the system to be in a fault state for a long time, affecting the rapid recovery of MACP-CHB-ESS operation control after the fault, when the fault is detected, a trip signal is sent to the circuit breaker at the fault port of the device to make it act immediately and cut off the connection with the faulty feeder.

[0049] When a system fault occurs and the short-circuit current is too large, and the device operation cannot ensure the safe fault crossing of the power device, the device must be reliably locked and the device must be safely switched through the TBS bypass. After the fault is isolated, the device can be put back into operation to restore the charging, discharging and power flow regulation functions of the MACP-CHB-ESS, and achieve the optimized operation of the "new" source-grid-load-storage system after the fault. The control mode of each port of the MACP-CHB-ESS is different according to the type of interconnected feeder. The active power command value of the balanced feeder is closely related to the charging and discharging power of the CHB-ESS. After a permanent fault occurs and is removed, a new balanced feeder needs to be reselected, and the control mode of its interconnected port needs to be switched before the control is put into operation again.

[0050] When an unbalanced feeder fails, each interconnected port of MACP-CHB-ESS can maintain the original control mode without switching.

[0051] When the fault of the balanced feeder is detected, the protection system responds quickly and completes the device protection measures of locking the MACP-CHB-ESS converter and turning on the TBS. At the same time, the control system learns that the balanced feeder has failed, and reselects one of the remaining normally operating feeders as the balanced feeder and performs control switching. The control switching mainly includes phase-locked loop input switching and port control mode switching. The phase-locked loop input of the system is switched from the three-phase voltage at the original balanced feeder interconnection port to the three-phase voltage at the new balanced feeder interconnection port. The interconnection port control mode of the MACP-CHB-ESS connected to the new balanced feeder is switched, and its active command value is determined by the charging and discharging power of the CHB-ESS, while its reactive power is controlled by the reactive component of the CHB-ESS output current. The series voltage reference value calculated by the output modulation optimization of the PFCM connected to the feeder no longer outputs the reference voltage required for P / Q control. According to the above analysis, at the moment of TBS locking, the control loop of the CHB-ESS still has a good control effect. Therefore, at the moment of TBS blocking, the inputs of the CHB-ESS voltage outer loop PI controller and the current inner loop PI controller can be set to zero, and the PI controller output before blocking can be maintained to achieve a smooth transition when control is restored.

[0052] After waiting for the circuit breaker at the MACP-CHB-ESS interconnection port exit to trip, the fault isolation is completed. Since the CHB-ESS has the same capacity as the feeder, its control can be restored first, the PI controller input of the voltage outer loop and the current inner loop is canceled and set to zero, and the new CHB-ESS current reference value is switched according to the given conversion rate to avoid excessive current overshoot. After the control of the CHB-ESS is restored, the power flow control function of the remaining interconnected feeders can be restored. During the fault of the balanced feeder, the feeder power flow is out of control, and the PI controller of the control loop is in a saturated state. Directly re-entering the controller will bring excessive current shock to the system. Therefore, before re-entering the power flow control loop, its PI controller needs to be reset and restored to the initial state. At the same time, when the feeder power flow and current instructions are given, their change rate is limited to reduce the impact on the system when the power flow control function is restored. At the same time, the PFCM DC bus voltage control is restored to stabilize the PFCM DC bus voltage at the set value.

[0053] Example 2, reference Figure 4 , which is an embodiment of the present invention, provides a system suitable for a post-fault recovery and re-operation method of a source-grid-load-storage system, characterized in that it includes a cascaded full-bridge sub-module 100, a half-bridge sub-module 200 and a flow control module 300.

[0054] The cascaded full-bridge submodule consists of two half-bridge submodules connected in parallel for integration into a medium voltage AC port.

[0055] The half-bridge submodule is used to expand the number of AC ports in the system.

[0056] The power flow control module consists of the main loop of FBSM and the newly added HBSM, which is responsible for controlling the power flow and maintaining the energy balance within the system.

[0057] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program code.

[0058] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0059] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0060] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0061] Example 3, reference Figure 5-Figure 10 In this embodiment, in order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiments. This embodiment experiments the existing traditional method and the method of this embodiment respectively.

[0062] In this embodiment, MACP-CHB-ESS connects three feeders, and feeder 2 is set as the balanced feeder before the fault, and feeder 1 is set as the new balanced feeder after the fault is isolated. When a three-phase short circuit fault occurs in feeder 2, the simulation results of the fault isolation and power flow control function recovery of the "source-grid-load-storage system" distribution system are as follows: at t = 0.1s, a three-phase short circuit fault occurs in feeder 2; at t = 0.1015s, MACP-CHB-ESS is locked, and TBS is triggered at the same time, and feeder 1 is reselected as the balanced feeder; at t = 0.15s, the faulty feeder is isolated; at t = 0.2s, the control of CHB-ESS and the new balanced feeder is restored; at t = 0.5s, the feeder power flow control and the PFCM DC bus voltage are restored.

[0063] The application of the above structure and method is further illustrated below in conjunction with a specific simulation example. In conjunction with the above embodiment, MATLAB / Simulink software is used to perform simulation verification on the system, and the simulation parameters are shown in Table 1.

[0064] Table 1 Simulation parameters

[0065]

[0066] Figures 5 to 7 The waveforms are the current waveforms of the three feeders respectively. Figures 8 to 10 They are: CHB-ESS current waveform, PFCM DC bus voltage, and three feeder power flows.

[0067] The simulation results show that the proposed post-fault recovery and re-operation technology can, after the feeder fault is isolated in the AC feeder area, restore the charging and discharging control of the CHB-ESS first, and then restore the power flow decoupling control of the unbalanced feeder by means of setting the PI controller input to zero, resetting the PI controller, limiting the change rate of the feeder power flow and the current reference value, etc., to help the MACP-CHB-ESS-based energy storage sharing flexible interconnection system achieve a smooth transition from "short-circuit fault state-natural power flow state-optimized operation state".

[0068] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for recovering and re-operating a source-grid-load-storage system after a fault, characterized in that: include: Check whether the system has any malfunction; When a system failure occurs, determine the specific cause of the failure; Take different measures according to different fault causes.

2. The method for post-failure recovery and re-operation of a source-grid-load-storage system according to claim 1, characterized in that: When the fault occurs, the safety protection measures are immediately initiated.

3. The method for post-failure recovery and re-operation of a source-grid-load-storage system according to claim 2, characterized in that: When a fault occurs in the system, the device is safely switched over through the TBS bypass, and is put back into operation after the fault is isolated, thereby restoring the charging, discharging and power flow regulation functions of the MACP-CHB-ESS.

4. The method for post-failure recovery and re-operation of a source-grid-load-storage system according to claim 3, characterized in that: The specific fault causes include a balanced feeder fault and an unbalanced feeder fault.

5. The method for post-failure recovery and re-operation of a source-grid-load-storage system according to claim 4, characterized in that: The different measures include, when a balanced feeder fault occurs, activating the TBS to bypass the lower switch tube of the half-bridge submodule in the PFCM and immediately locking all the half-bridge submodules; When the TBS is activated, it quickly locks the CHB-ESS, reducing the current in the parallel branch to zero, and simultaneously, upon detecting a fault, sends a trip signal to the circuit breaker at the fault port of the device, causing the circuit breaker to cut off the connection with the faulty feeder.

6. The method for post-failure recovery and re-operation of a source-grid-load-storage system according to claim 5, characterized in that: When a balanced feeder failure occurs, the control system further includes, after the balanced feeder failure occurs, reselecting one of the remaining normally operating feeders as the balanced feeder and performing control switching; The control switching includes phase-locked loop input switching and port control mode switching, wherein the phase-locked loop input of the system is switched from the three-phase voltage at the original balanced feeder interconnection port to the three-phase voltage at the new balanced feeder interconnection port, and the interconnection port control mode of the MACP-CHB-ESS connected to the new balanced feeder is switched, the active command value is determined by the CHB-ESS charging and discharging power, and the reactive power is controlled by the reactive component of the CHB-ESS output current. At the moment of TBS locking, the inputs of the CHB-ESS voltage outer loop PI controller and the current inner loop PI controller are set to zero, and the PI controller output before locking is maintained; After the circuit breaker at the MACP-CHB-ESS interconnection port exit trips and the fault isolation is completed, the control is restored first, the PI controller inputs of the voltage outer loop and the current inner loop are reset to zero, and the new CHB-ESS current reference value is switched according to the given conversion rate; After the control of CHB-ESS is restored, the PI controller is reset to restore the initial state before the power flow control loop is put into use again. At the same time, when the feeder power flow and current instructions are given, the change rate is limited. At the same time, the PFCM DC bus voltage control is restored to stabilize the PFCM DC bus voltage at the set value.

7. The method for post-failure recovery and re-operation of a source-grid-load-storage system according to claim 6, characterized in that: The taking of different measures also includes that, when an unbalanced feeder fault occurs in the system, each interconnected port of MACP-CHB-ESS maintains the original control mode without switching.

8. A system using the method for post-failure recovery and re-operation of a source-grid-load-storage system as claimed in any one of claims 1 to 7, characterized in that: It comprises a cascaded full-bridge submodule (100), a half-bridge submodule (200) and a power flow control module (300); The cascaded full-bridge submodule is composed of two parallel half-bridge submodules for integration into a medium voltage AC port; The half-bridge submodule is used to expand the number of AC ports of the system; The power flow control module is a main loop consisting of FBSM and a newly added HBSM, which is responsible for controlling the power flow and maintaining the energy balance within the system.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the post-failure recovery and re-operation method applicable to a source-grid-load-storage system according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the post-fault recovery and re-operation method applicable to a source-grid-load-storage system as described in any one of claims 1 to 7 are implemented.

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