Power support and network coordination control method, system and device for photovoltaic storage flexible interconnected transformer area and medium

Abstract

The application discloses a photovoltaic- energy storage flexible interconnected power supply area power support and network construction cooperative control method, system, equipment and medium, relates to the power system distribution automation technical field, and includes the following steps: establishing a local shared data area by collecting data and configuration parameters, discriminating faults and controlling the migration of the operating state, calculating the supportable power of non-fault power supply areas and scheduling load transfer batches, independently arbitrating and determining the master control unit according to the local DC voltage recovery condition, establishing the AC voltage and frequency reference, determining the initial support power before network construction, releasing the first batch of loads after network construction and sequentially recovering subsequent batches, dynamically adjusting the active power instruction of each support unit during the recovery period, deciding to continue, maintain or back off after each batch is checked, and updating the network construction droop coefficient, and smoothly exiting the fault support after meeting the recovery condition. The application realizes the whole-process closed-loop cooperative control from discrimination to recovery exit of the photovoltaic- energy storage flexible interconnected distribution network after a fault.

Description

Technical Field

[0001] This invention relates to the field of power system distribution automation technology, specifically to methods, systems, equipment, and media for power support and grid-connected collaborative control of flexible interconnected photovoltaic and energy storage distribution areas. Background Technology

[0002] With the large-scale integration of distributed photovoltaic and energy storage systems into low-voltage distribution networks, traditional radial distribution networks face significant challenges in addressing power imbalances in transformer substations and ensuring rapid load recovery after faults. Flexible interconnection technology, through voltage source converters, interconnects multiple AC distribution substations on the DC side, forming a low-voltage flexible interconnection distribution system. This provides a new technical approach for the rapid transfer of power and power support to faulty substation loads. While the current master-slave control architecture can effectively maintain DC voltage stability and reasonable power distribution during normal system operation, after a transformer fault takes off, the original DC voltage master control unit may lose its regulation capability. In the absence of communication, the flexible interconnection unit of the non-faulty substations must quickly take over DC voltage control. Simultaneously, the converter connected to the faulty substation establishes AC voltage and frequency references to support continuous power supply to the faulty substation loads.

[0003] Existing control methods still have several technical limitations in the role competition and load restoration process after a fault: First, the takeover of the DC voltage master control unit mostly relies on a preset single priority or external communication confirmation, lacking a competition suppression mechanism based on the local DC voltage dynamic response. This can easily lead to multiple candidate units switching to constant DC voltage control mode simultaneously, causing DC bus voltage oscillation or power circulating current, and even resulting in support interruption. Second, the process of the converter in the faulty area switching from constant power control to grid-building control lacks coordination with the load restoration sequence. If the grid-building voltage establishment, support power preparation, and load input are only connected by a fixed delay, the actual system state may not match the preset sequence, resulting in secondary load voltage loss or converter overcurrent. Third, the droop coefficient of grid-building droop control usually adopts a fixed setting value and fails to adjust with the actual restored load composition line. When the load type deviates significantly from the preset operating conditions, it is difficult to maintain the frequency and voltage support effect within the ideal range. Summary of the Invention

[0004] In view of the above-mentioned existing problems, the present invention provides a method, system, equipment and medium for power support and grid-based coordinated control of flexible interconnected distribution areas with photovoltaic and energy storage, in order to solve the problems in the prior art that cause oscillations due to competition of DC voltage master control by multiple units during power support and load recovery after distribution transformer failure, recovery failure due to mismatch between grid voltage establishment and load input timing, and insufficient frequency voltage support due to mismatch between droop coefficient and load.

[0005] To address the aforementioned technical challenges, a method for power support and grid-based coordinated control of flexible interconnected photovoltaic and energy storage substations is proposed, including: Data acquisition and parameter configuration are performed to establish a local shared data area. Faults are identified and operational status migration is controlled based on DC bus voltage and rate of change. The available power for non-faulty transformer areas is calculated, and load transfer batches are scheduled. Using preset role competition parameters, each candidate unit autonomously arbitrates and determines the DC voltage master control unit based on the local DC voltage recovery status. Soft start of grid construction is performed on faulty transformer areas, and AC voltage and frequency references are established. The initial support power is determined before grid construction is ready. After grid construction is ready, the first batch of loads is released in batches and subsequent batches are restored sequentially. During the restoration period, the active power commands of each non-faulty power support unit are dynamically adjusted according to the changes in DC bus voltage. Each batch is verified, and the batch is controlled to continue, maintain, or revert based on the verification results. The grid droop coefficient is updated based on the proportion of load types that have passed the verification. When the restoration conditions are met, the fault support status is smoothly exited and restored to the normal control mode.

[0006] As a preferred embodiment of the power support and grid-based collaborative control method for flexible interconnected distribution areas with photovoltaic and energy storage described in this invention, the method of identifying faults and controlling the migration of operating states includes: collecting electrical quantities and storing them in a local shared data area after preprocessing; establishing variables such as status, events, roles, capacity, batches, instructions, parameter update permissions, and over-limit flags in the current data area; and presetting slow-changing parameters locally. The rate of change is calculated using the DC bus voltage. When the voltage and rate of change continuously meet the preset fault criteria within the preset sliding window, the system enters the fault pre-switching state. If the preset confirmation time is exceeded, a fault event flag is generated and the system enters the fault support state. The operating state is switched with hysteresis between normal, fault pre-switch, fault support and recovery transition states according to the preset state transition logic.

[0007] As a preferred embodiment of the power support and grid-based collaborative control method for flexible interconnected distribution areas with photovoltaic and energy storage described in this invention, the method of scheduling load transfer batches includes reading the real-time operating data of each non-faulty distribution area in the local shared data area after detecting a fault event flag. The maximum supportable power is calculated based on the transformer capacity, preset load rate limit, real-time load rate, and power factor of each non-faulty distribution area. Compare the load demand of the faulty transformer area with the sum of the maximum support power of all non-faulty transformer areas to determine the loads that must be cut off, the loads that can be transferred, and the remaining support margin. Load restoration batches are arranged according to the principle of prioritizing the restoration of Category I loads, staggering the peak-hour operation of Category II loads, and dispersing the operation of Category III loads. The restoration power of each batch shall not exceed the preset allocation ratio of the remaining support margin for the current period. Write the load restoration batch and available load information to the local shared data area.

[0008] As a preferred embodiment of the power support and grid-building collaborative control method for flexible interconnected distribution areas with photovoltaic and energy storage described in this invention, the step of performing grid-building soft start and establishing AC voltage and frequency references for faulty distribution areas includes, according to the status information in the local shared data area, after entering the fault pre-switching state, each candidate non-faulty unit reads the pre-stored role competition parameters. Each candidate unit starts a local waiting timer. The highest priority unit that meets the takeover conditions switches to constant DC voltage control mode first. If the DC voltage stops decreasing or starts to rise locally, the remaining candidate units withdraw their takeover requests. If the DC voltage does not recover after its own waiting timer expires, the next priority unit takes over and writes the final determined DC voltage master control unit role into the local shared data area. The faulty transformer unit establishes AC voltage amplitude and frequency references based on a preset limited slope. When the AC voltage, frequency and converter current are all within the preset allowable range and the preset verification time is reached, a network ready flag is generated and written to the local shared data area.

[0009] As a preferred embodiment of the power support and grid construction coordination control method for flexible interconnected power distribution areas with photovoltaic and energy storage described in this invention, the active power instruction for dynamically adjusting each non-faulty power support unit includes: before the grid construction readiness flag is generated, reading the first batch of load demand in the local shared data area, calculating the initial support power based on the current demand and estimated loss, and allocating it according to the allocation coefficient obtained by normalization of the maximum supportable power of each non-faulty unit. Once the network ready flag is set, the initial support power and the first batch of loads will be released synchronously at a preset limited slope. After the support amount reaches the preset ratio of the first batch of demand, the load switch can be closed. Subsequent loads are put into operation in batches. During the current period, the non-faulty unit with the largest transformer capacity maintains the DC voltage stability. The remaining support units calculate and correct the active power command based on the allocation coefficient, DC bus voltage deviation and rate of change, actual output of each unit and remaining capacity. The correction results are issued after being constrained by capacity limit and rate of change.

[0010] As a preferred embodiment of the power support and grid construction collaborative control method for flexible interconnected distribution areas with photovoltaic and energy storage described in this invention, the method of updating the grid droop coefficient includes pausing the release of subsequent batches after each batch is deployed, and detecting the DC bus voltage and rate of change, the AC voltage and frequency of the faulty distribution area, the grid construction unit current and the remaining capacity of the support unit within a preset verification period. When all testing volumes are within the allowable range, open the next batch; when a testing volume is close to the limit but has not exceeded the limit, maintain the current batch and increase the output of support units with margin; when any hard limit is exceeded and the preset limit confirmation time continues, cancel the most recently deployed low-priority batch. The faulty transformer unit operates in a droop-based control mode, updating the active droop coefficient and reactive droop coefficient based on the proportion of the first load type and the proportion of the second load type in the verified load batches.

[0011] As a preferred embodiment of the power support and grid-based collaborative control method for flexible interconnected photovoltaic and energy storage distribution areas described in this invention, the smooth exit from the control fault support state and restoration to the normal control mode includes the following: when the DC bus voltage and rate of change meet the preset recovery criteria and continue to reach the preset recovery time, and there are no pending over-limit flags in the local shared data area and all the batches that have been put into operation have passed the verification, the system is moved to the recovery transition state and the addition of new loads is stopped. Fix the currently verified active droop coefficient and reactive droop coefficient, and reduce the support command of the non-master control support unit according to the preset exit slope; After the support power drops below the preset residual, the faulty unit will be restored to normal control mode. After confirming that the new DC voltage master control unit has established voltage regulation, switch back the DC voltage master control. The exit from each stage is at least one preset verification period, and the previous stage verification is passed as a condition. If the electrical quantity exceeds the limit in any stage, the exit will be suspended or rolled back.

[0012] The beneficial effects of this preferred technical solution are as follows: through closed-loop event-driven, non-communication-coordinated, and load-adaptive network parameter dynamic updates, coupled with gradual smooth exit, stable and coordinated control is achieved throughout the entire process from fault diagnosis to recovery and exit.

[0013] As a preferred embodiment of the power support and grid construction collaborative control system for flexible interconnected photovoltaic and energy storage substations described in this invention, it is characterized by including a fault perception and discrimination module, a support evaluation and orchestration module, an arbitration and grid construction start-up module, a dynamic power support module, and a verification and recovery management module.

[0014] The fault perception and discrimination module is used to collect and preprocess electrical quantities, establish a local shared data area containing status, events and flags, and use DC voltage and rate of change to judge faults within a preset window, driving the state machine to migrate with hysteresis between normal, pre-switching, support and recovery states.

[0015] The support assessment and orchestration module is used to read data from non-faulty transformer areas in the shared area, calculate the maximum supportable power, compare fault requirements to determine the loads to be cut off and those that can be transferred, and orchestrate batches according to load priority, with the power of each batch not exceeding a preset proportion of the remaining margin.

[0016] The arbitration and network initiation module is used for each candidate unit to autonomously compete for the DC voltage master control based on preset priority and differentiated waiting sequence by locally detecting the DC voltage recovery status. The faulty transformer unit establishes voltage and frequency references according to the limited slope and generates a network ready flag.

[0017] The dynamic power support module is used to determine the initial support power according to the first batch of demand and allocation coefficient before the grid is ready. After the grid is ready, the first batch of power is released synchronously and put into operation with subsequent batches. The support unit corrects the active power command in real time according to the DC voltage deviation and issues it after limiting and rate of change constraints.

[0018] The verification and recovery management module is used to perform multi-dimensional electrical quantity verification after batch deployment, and decide whether to continue, maintain or roll back. It dynamically updates the droop coefficient based on the proportion of the verified load type. After the recovery conditions are met, it sequentially reduces the support increment, switches back the main control, and smoothly exits fault support.

[0019] A computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the steps of a method for power support and network collaborative control of flexible interconnected distribution areas including optical storage.

[0020] A computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of a method for power support and network collaborative control of flexible interconnected distribution areas including optical and energy storage.

[0021] The beneficial effects of this invention are as follows: By establishing a local shared variable area and a modular software architecture, this invention links fault diagnosis, task generation, role arbitration, instruction execution, and result verification into a state-driven closed-loop process. This ensures that subsequent steps are triggered by the actual execution results of the previous step rather than proceeding with a fixed delay, guaranteeing the timing matching and action coordination of each control link at the software architecture level. Fault diagnosis and four-state finite state machine transition are performed based on the local DC bus voltage and its rate of change. Hysteresis exit thresholds and continuous confirmation times prevent false triggering by transient disturbances, providing reliable startup conditions for subsequent support processes. Differentiated load recovery batches are formed by calculating the capacity margin of non-faulty transformer areas, matching the transferred power with the actual remaining capacity. Furthermore, through a communication contention suppression mechanism, candidate units autonomously arbitrate and withdraw requests based on the local DC voltage recovery status, achieving plug-and-play master control takeover. Simultaneously, soft-start network construction is performed with a limited slope. To prevent voltage build-up failure due to current surges, the basic support power is pre-locked before the network is ready, and released synchronously with the first batch of loads after the network is ready, rather than all power being put into operation at once. This ensures that the network voltage build-up, power preparation, and load input are matched in timing. The DC bus voltage is used dynamically as a common information channel for the power deficit of the network units, so that each power support unit can locally sense the deficit change and adjust the output according to the participation coefficient without inter-station communication. The electrical quantities after each batch of loads is put into operation are checked, and the decision to continue, maintain, or revert is made based on the results. At the same time, the droop coefficient is updated online based on the actual load type ratio that has passed the check, instead of using a fixed setting value, to avoid mismatch between network parameters and actual load types. The system exits in a step-by-step manner with a limited slope, in the order of stopping new loads, reducing support power, and restoring master control, so that the system does not cause secondary disturbances due to the sudden removal of support when returning to normal mode, thus realizing a complete control closed loop from the occurrence of a fault to recovery and exit. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used 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 those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 The above is a flowchart of a method for power support and network collaborative control of flexible interconnected photovoltaic and energy storage substations, provided in one embodiment of the present invention.

[0024] Figure 2 This is a schematic diagram of the batch verification and recovery management process of a method for power support and network collaborative control of flexible interconnected photovoltaic and energy storage substations, provided in one embodiment of the present invention.

[0025] Figure 3The flowchart shows a system scheme for a power support and grid-based collaborative control system for flexible interconnected photovoltaic and energy storage substations, provided in one embodiment of the present invention. Detailed Implementation

[0026] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0027] Example 1, referring to Figure 1 As one embodiment of the present invention, a method for power support and network collaborative control of flexible interconnected distribution areas including optical and energy storage is provided, comprising: S100: Performs data acquisition and parameter configuration, establishes a local shared data area, and identifies faults and controls the migration of operating status based on DC bus voltage and rate of change.

[0028] S200: Calculates the available power for non-faulty transformer areas and schedules load transfer batches.

[0029] S300: Using preset role competition parameters, each candidate unit autonomously arbitrates and determines the DC voltage master control unit based on the local DC voltage recovery status, performs network soft start for the faulty area, and establishes AC voltage and frequency references.

[0030] S400: Determine the initial support power before the network is ready. After the network is ready, release the first batch of loads in batches and restore the subsequent batches in sequence. During the restoration period, dynamically adjust the active power command of each non-faulty power support unit according to the change of DC bus voltage.

[0031] S500: Verify each batch, control the batch to continue, maintain or roll back based on the verification results, and update the network droop coefficient based on the proportion of load types that have passed the verification. When the recovery conditions are met, control the fault support state to smoothly exit and restore to the normal control mode.

[0032] It should be noted that this invention achieves state-driven timing matching and autonomous master control takeover without communication contention suppression through a modular closed-loop architecture. Combined with the synchronous release of grid construction and power preparation, multi-unit collaborative support with DC bus dynamics as the information channel, and online adaptive updating of grid parameters based on actual restored loads, along with step-by-step smooth exit, it realizes the collaborative control of the entire process from fault identification to recovery exit.

[0033] Example 2, refer to Figure 1 and Figure 2This is a second embodiment of the present invention, which provides a method for power support and network collaborative control of flexible interconnected distribution areas including optical and energy storage, comprising: In step S100, the step of determining the fault based on the DC bus voltage and rate of change and controlling the transition of the operating state includes steps S101 to S103: S101: Collect electrical quantities and store them in the local shared data area after preprocessing. Establish status, event, role, capacity, batch, instruction, parameter update permission and over-limit flag variables in the current data area, and pre-set slow-changing parameters locally.

[0034] Each flexible interconnection unit collects DC bus voltage, AC three-phase voltage and current, equipment operating limits, and fault area load list with a set control cycle of 1ms.

[0035] It should be noted that the preprocessing of the collected data includes sequentially performing first-order low-pass filtering or moving average filtering, outlier limiting or removal, validity verification, and per-unit processing; when continuous measurements exceed the physical range or the abrupt change in adjacent samples exceeds the set upper limit, a measurement anomaly flag is set, and the most recent valid value is used within a verification window; when configuring redundant measurement channels, the validity condition is that the difference between the two channels does not exceed the upper limit of measurement accuracy.

[0036] The preprocessed data is stored in the controller's local shared data area. The local shared data area is specifically implemented using a shared variable area allocated in the controller's memory. It contains variables such as running status code, fault event flag, master control role flag, supported capacity limit, load recovery batch number, supported power reference value, network parameter update permission flag, and over-limit fallback flag, which are called by the status judgment, task orchestration, role arbitration, dynamic power allocation, network parameter generation, stability verification, and smooth recovery modules.

[0037] Simultaneously, slow-changing parameters are pre-set in the local parameter area. These slow-changing parameters specifically include the rated capacity of the distribution transformer in the area, the priority of the main control takeover of non-faulty units, the different takeover waiting sequences, the load priority and load type of the faulty distribution area. These parameters are stored in the form of a configuration table, and the configuration table fields include at least the distribution area number, rated capacity, availability status, capacity margin, takeover priority, waiting time, load level, and load type. The rated capacity and load level are pre-set manually or from the operation log, while the capacity margin and equipment health status are automatically refreshed by the operation data. The takeover priority is first sorted from largest to smallest according to the capacity margin. When the capacity margins are the same, the equipment health status and the electrical distance to the faulty distribution area are compared in turn. The priority is re-sorted when the system is in normal operation or when the equipment status changes.

[0038] It should also be noted that slow variables used for load composition and droop parameter updates are updated on a 100ms cycle or load batch verification event basis.

[0039] S102: Calculate the rate of change using DC bus voltage. When the voltage and rate of change continuously meet the preset fault criteria within the preset sliding window, enter the fault pre-switching state. If the preset confirmation time is exceeded, a fault event flag is generated and the fault support state is entered.

[0040] Each flexible interconnection unit collects the DC bus voltage in real time and calculates the DC voltage change rate, expressed by the formula: in, The DC voltage change rate reflects the rate of change of the DC bus voltage over time. The local DC bus voltage is collected in real time by each flexible interconnection unit. It is a time variable.

[0041] Furthermore, the preset sliding window specifically adopts a sliding detection time window Ts, which in this embodiment is 10ms. When the DC bus voltage and rate of change meet the preset fault criteria, it is determined that the system has a transformer fault or a serious power imbalance in the distribution area, and the control software enters the fault pre-switching state. The preset fault criterion formula is expressed as: in, This is a dimensionless indicator for fault event judgment. When it is true (1), it indicates that a transformer fault or a serious power imbalance in the distribution area has been detected. The DC voltage lower limit threshold is set to 0.90 pu of the rated value. The threshold for the rate of change of DC voltage; This refers to the AC side voltage, specifically the locally acquired AC voltage amplitude or RMS value. For logical AND operator, For logical "OR" operator, The threshold value is the lower limit of AC voltage. The criterion indicates that a fault occurs when the DC voltage is lower than the lower limit and the rate of change exceeds the limit, or when both the AC voltage and the DC rate of change exceed the limit.

[0042] It should be noted that different transformer substations can be per-unit adjusted according to their rated capacity and allowable voltage deviation, but the criterion structure remains unchanged. The formula is expressed as follows: in, To restore the criterion flag, a value of 1 indicates that the recovery conditions for exiting the fault support state have been met. The DC voltage recovery threshold is set to 0.95 pu. The threshold for the rate of change recovery.

[0043] If the current fault pre-switching state continues for more than the preset confirmation time, i.e., the fault confirmation time Tc (20ms in this embodiment), then a fault event flag is generated and the fault support state is triggered.

[0044] It should also be noted that the fault event flag is written to the local shared data area in the format of "event type - status code - timestamp - valid flag", and is read by the support task orchestration module and the control role arbitration module; the event types include at least transformer faults, severe power imbalance in the transformer area, and measurement anomalies.

[0045] When a measurement anomaly or converter self-locking occurs, the corresponding unit is only marked as not eligible to participate in master control takeover or power support, and the current unit is not directly triggered to enter network control.

[0046] S103: The operating state is switched with hysteresis between normal, fault pre-switch, fault support and recovery transition states according to the preset state transition logic.

[0047] The transition of the operating state is implemented by the preset state transition logic, which specifically adopts a four-state finite state machine including "normal operation - fault pre-switch - fault support - recovery transition". The state transition with hysteresis is achieved by limiting the entry threshold, exit threshold, continuous confirmation time and instruction change rate.

[0048] The transition from normal operation to fault pre-switching requires valid measurement data and that the unit is not locked; the transition from fault pre-switching to fault support requires the fault condition duration Tc, the completion of support capability assessment, and that at least one candidate DC voltage main control unit and the fault area network unit are both available; the transition from fault support to recovery transition requires that the DC voltage recovery conditions be met simultaneously. and The AC voltage, frequency, and converter current in the faulty transformer area are within the allowable range, and there are no pending limit exceedance flags in the local shared data area. The DC voltage recovery threshold is set to 0.95 pu. The rate of change recovery threshold, and , To form a hysteresis loop; the recovery transition to normal operation requires the above recovery conditions to continuously reach the preset recovery time Tr, which is 100ms in this embodiment, the support increment drops to the preset residual, that is, the support power change does not exceed 2% of the rated power and the DC voltage master control role is confirmed; if any prerequisite fails, the state machine maintains the current state or rolls back to the previous safe state.

[0049] When satisfied and After the recovery conditions are met and Tr is maintained, the system smoothly recovers from fault support mode to normal master-slave control mode.

[0050] In step S200, the scheduling of load transfer batches includes steps S201 to S203: S201: After detecting a fault event flag, read the real-time operating data of each non-faulty transformer area in the local shared data area, and calculate the maximum supportable power based on the transformer capacity, preset load rate limit, real-time load rate and power factor of each non-faulty transformer area.

[0051] Specifically, after the above steps generate a fault event flag, the real-time operating data of each non-faulty station in the local shared data area is read, and the maximum supportable power of each non-faulty station i is calculated using the following formula: in, Let be the maximum supportable power of the i-th non-faulty station area. For the capacity of the distribution transformer in area i, The preset load rate limit allowed by the distribution transformer during a given support duration is set within the range of 0.80 to 1.00 pu based on the nameplate capacity, thermal stability limit, and operating procedures. When short-term overload is allowed, it can be increased according to the equipment procedures. Real-time load rate; The power factor. and The values ​​are calculated from local three-phase voltage and current, and updated after a sliding average of 10 to 20 rapid control cycles. In case of measurement anomalies, the aforementioned effective values ​​are used for processing.

[0052] S202: Compare the load demand of the faulty transformer area with the sum of the maximum support power of all non-faulty transformer areas to determine the loads that must be cut off, the loads that can be transferred, and the remaining support margin.

[0053] Specifically, the load demand of the faulty transformer area is compared with the sum of the maximum support capacity of all non-faulty transformer areas to calculate the load that must be cut off. The formula is as follows: in, This represents the load power that must be cut off from the faulty transformer area, indicating that the faulty transformer area still cannot meet the load gap even after all non-faulty transformer areas provide the maximum supportable power. This refers to the load demand power of the faulty transformer area, which is the actual total load of the transformer area before or at the current moment. This represents the total number of non-faulty areas. For summation index number; when the total supportable power is greater than the fault requirement, the difference is reserved for DC voltage regulation and load start-up margin; when the total supportable power is insufficient, loads are cut off from low to high priority, and within the same priority, loads with larger start-up impact or larger capacity are cut off first.

[0054] S203: Arrange load restoration batches according to the principle of prioritizing the restoration of Category I loads, staggering the peak-load operation of Category II loads, and dispersing the operation of Category III loads. The restoration power of each batch shall not exceed the preset allocation ratio of the remaining support margin for the current period. Write the load restoration batch and available load information into the local shared data area.

[0055] Specifically, after determining the load that can be transferred, the load restoration batches are arranged. The arrangement follows the principles of prioritizing the restoration of Category I loads, staggering the peak-hour operation of Category II loads, and dispersing the operation of Category III loads.

[0056] It should be noted that the first category of loads specifically refers to important loads, determined based on the consequences of power outages and the load level table; the second category of loads specifically refers to power loads, loads with significant start-up impact; and the third category of loads specifically refers to constant power loads or electronic power interface loads.

[0057] The restoration power of each batch shall not exceed the preset allocation ratio of the remaining support margin for the current period. Specifically, the preset allocation ratio is 80%, and generally does not exceed 10% to 20% of the total demand of the faulty area. The second type of load shall be separated from adjacent batches by a preset waiting period, specifically 100 to 300 ms, and shall be staggered from starting large-capacity motors. The third type of load shall be distributed to different batches and the proportion of a single batch shall not exceed the preset proportion limit of the restoration power of the current batch, specifically 30%.

[0058] After the orchestration is completed, the load restoration batches and the corresponding load information for each batch are written to the local shared data area for use in subsequent steps.

[0059] In step S300, the step of performing a soft start-up of the faulty transformer area and establishing an AC voltage and frequency reference includes steps S301 to S303: S301: Based on the status information in the local shared data area, after entering the fault pre-switching state, each candidate non-faulty unit reads the pre-stored role competition parameters.

[0060] After entering the fault pre-switch state, each candidate non-faulty flexible interconnection unit reads the pre-stored role contention parameters. Specifically, the role contention parameters adopt the master control takeover priority number corresponding to the capacity margin and different takeover waiting sequences. It should be noted that the master control takeover priority number corresponding to the capacity margin is 1 to N, and the smaller the value, the higher the priority. The different takeover waiting sequences include the waiting time corresponding to each level of candidate unit. The basic waiting interval is greater than the time required for fault confirmation and mode switching. In this embodiment, it is taken as 20ms.

[0061] S302: The priority sorting rules include first sorting by capacity margin from largest to smallest, and then, if the capacity margins are the same, comparing the equipment health status and the electrical distance to the faulty area in turn.

[0062] Each candidate unit starts its local waiting timer. The highest priority unit that meets the takeover conditions (i.e., its own capacity margin, AC side voltage, and converter status are normal) switches to constant DC voltage control mode first. If, after the current unit takes over, the local system detects that the DC bus voltage stops decreasing or starts to rise within a continuous detection window, the remaining candidate units immediately cancel their takeover requests and maintain constant active power support. If no DC voltage recovery is detected after the current unit's waiting timer expires, the next priority candidate unit continues to take over.

[0063] This allows for contention suppression without communication by monitoring the local DC voltage recovery status, and the final determined role of the DC voltage master control unit is written into the local shared data area.

[0064] S303: The fault area unit establishes AC voltage amplitude and frequency references based on the preset limited slope. When the AC voltage, frequency and converter current are all within the preset allowable range and the preset verification time is reached, a network ready flag is generated and written to the local shared data area.

[0065] At the same time, the flexible interconnection equipment connected to the faulty area, as an active network support unit, enters the network soft start process. The current unit gradually establishes the AC voltage amplitude and frequency reference according to the preset limited slope.

[0066] Specifically, the voltage amplitude increases from zero ramp to the rated value of 1.0 pu within 100–300 ms, with the frequency centered at the rated frequency, and the absolute value of the frequency change rate not exceeding 1 Hz / s; during the voltage and frequency ramping process, when the converter current reaches 0.9 times the rated current I... max The ascent will pause at time, reaching level I. max If the current unit fails to revert to the previous stable reference value, it will be marked as unavailable after two consecutive verification failures, and the process will return to the control role for arbitration.

[0067] It should be noted that grid readiness is determined when the following conditions are met simultaneously: AC voltage amplitude is within the range of 0.90 to 1.10 pu, frequency deviation does not exceed ±0.5 Hz, and converter current does not exceed 0.9 I. max And the above state continues for a preset verification time, specifically 100ms; at this time, a network ready flag is generated and written to the local shared data area.

[0068] In step S400, the dynamic adjustment of the active power command for each non-faulty power support unit includes steps S401 to S404: S401: Before the network readiness flag is generated, read the first batch of load demands in the local shared data area, calculate the initial support power based on the current demand and estimated losses, and allocate it according to the allocation coefficient obtained by normalization of the maximum support power of each non-faulty unit.

[0069] Specifically, before the network readiness flag is generated, all load switches in the faulty area remain locked, and the power support unit reads the first batch of recovery load requirements in the local shared data area and calculates the initial support power.

[0070] The initial support power is specifically taken as the sum of the active power demand of the first batch of restored loads and the estimated line loss and converter loss, and does not exceed the sum of the maximum support power of each power support unit minus the preset reserve capacity; the preset reserve capacity is specifically the adjustable capacity reserved by the DC voltage main control unit to suppress DC voltage fluctuations and does not participate in the normal power distribution.

[0071] After obtaining the initial total support power, it is allocated according to the allocation coefficient obtained by normalizing the maximum support power of each non-faulty unit, as expressed by the formula: in, , is the support allocation coefficient for the i-th non-faulty station area, dimensionless; each support unit latches the corresponding basic support reference value.

[0072] S402: When the network ready flag is set, the initial support power and the first batch of loads will be released synchronously at a preset limited slope. After the support amount reaches the preset ratio of the first batch of demand, the load switch can be closed.

[0073] Specifically, once the network readiness flag is set, the initial support power allocated above and the first batch of loads are released synchronously at another preset limited slope.

[0074] Here, the preset limited slope is taken as the minimum value among the power increment corresponding to the equipment's allowed active ramp rate, the allowable change rate of DC voltage, and the slope corresponding to the load switch connection time, so that the first batch of support power is released within 50 to 200 ms.

[0075] Once the support command actually reaches more than 90% of the preset proportion of the first batch of demand, the corresponding load switch can be closed to avoid secondary voltage drop caused by the load being put in first. After the first batch of loads stabilizes, the subsequent loads are put in order according to the order of the load recovery batches arranged in the shared area, and the actual execution result of each batch is used as the trigger condition for the release of the next batch.

[0076] S403: Subsequent loads are put into operation in batches. During the current period, the non-faulty unit with the largest transformer capacity maintains the DC voltage stability. The remaining support units calculate and correct the active power command based on the allocation coefficient, DC bus voltage deviation and rate of change, actual output of each unit and remaining capacity.

[0077] During the power support period, the non-faulty unit with the largest transformer capacity undertakes the DC voltage stabilization task. The current unit switches to constant DC voltage control mode, and the PI outer loop parameter K... P K i The closed-loop bandwidth method is used for setting, with the outer loop bandwidth not exceeding 1 / 5 of the inner current loop bandwidth, to maintain the DC bus voltage at its steady-state rated value.

[0078] The remaining support units dynamically correct the active power command within 1ms of each fast control cycle. The correction method includes reading the allocation coefficient, the sum of the total active power demand and losses of the confirmed recovery batches, the DC bus voltage deviation and rate of change, the actual output and remaining capacity of each unit, and calculating the active power reference value. The calculation formula is expressed as follows: in, This is the active power reference value for the i-th non-faulty transformer area, i.e., the power support unit. For the minimum value operator, This is the sum of the total active power demand of the confirmed recovery batches, plus line losses and converter losses; that is, the total net active power support that currently needs to be borne by all non-faulty transformer substations. This is the dynamic compensation coefficient.

[0079] S404: The correction result is sent out after being constrained by capacity limiting and rate of change. The correction result is sent to the converter after being checked by capacity limiting, active power rate of change limit and preset reserved capacity in sequence.

[0080] The coordination logic includes the following: when the DC voltage drops and the rate of change is high, it indicates that the DC power deficit of the network unit is increasing, and each support unit increases the support power according to the support allocation coefficient of the i-th non-faulty area; when the rate of change decreases but the voltage has not yet recovered, the command growth rate is reduced to avoid overshoot; when the voltage enters the recovery range and the rate of change approaches zero, the current support power is maintained and the load recovery task is allowed to enter the next batch of verification; if the DC voltage rises rapidly in the opposite direction, the most recently increased support power is reduced first to prevent excessive support from causing DC overvoltage.

[0081] When a support unit reaches its capacity limit, the current unit reference value is locked, and subsequent support increments are transferred to units that still have capacity. When all support units have no remaining capacity, the result of stopping release or executing load rollback is returned to the load recovery task.

[0082] like Figure 2 In step S500, updating the network sag coefficient based on the verified load type proportion includes steps S501~S504: S501: After each batch is put into operation, the release of subsequent batches is suspended. During the preset verification period, the DC bus voltage and rate of change, the AC voltage and frequency of the faulty transformer area, the current of the grid unit, and the remaining capacity of the support unit are detected.

[0083] The preset verification period is 100ms, which is 100 fast control cycles; for large-capacity power load batches, it can be extended to 200ms.

[0084] Furthermore, all detected quantities are within the preset allowable ranges, namely DC voltage 0.95–1.05 pu, AC voltage in the faulty area 0.90–1.10 pu, frequency deviation not exceeding ±0.5 Hz, and converter current not exceeding 0.9I. max If the remaining support margin is sufficient to cover the next batch, the current batch is deemed stable, and the next batch is opened.

[0085] When any detected quantity is close to the limit but has not exceeded it (e.g., the index is less than 5% away from the limit or the rate of change has not yet fallen below the recovery threshold), the current batch remains unchanged, and the output of the support unit with remaining margin is increased; when any hard limit is continuously exceeded for a preset limit confirmation time, or the converter current reaches I... max In this case, the most recently deployed low-priority load batches are cancelled, and the remaining support tasks are recalculated to achieve a safe rollback.

[0086] The preset over-limit confirmation time specifically adopts the fault confirmation time Tc.

[0087] S502: The faulty transformer unit operates in a droop-based control mode, updating the active droop coefficient and reactive droop coefficient based on the proportion of the first load type and the proportion of the second load type in the verified load batches.

[0088] During fault support, the flexible interconnected equipment connected to the faulty transformer area operates in a grid-type droop control mode, and the active power reference value is taken as the difference between the load demand of the faulty transformer area and the load to be cut off: in, This is the active power reference value for the flexible interconnected equipment connected to the faulty transformer area in the grid-type droop control mode; by detecting the actual output active power P and reactive power Q on the AC side, angular frequency reference and voltage amplitude reference are generated based on the active-frequency and reactive-voltage droop characteristics. The grid droop coefficient is not fixed, but is adjusted online adaptively according to the actual composition of the load that has been successfully restored and is operating stably.

[0089] Specifically, before the fault occurs, the power load ratio is obtained based on the power, reactive power, and current characteristics within the load ledger or a set sliding time window. and electronic power interface / constant power load ratio The initial value; during fault support, after each load batch passes the above stability check, the total active power P of all loads that have passed the check is recalculated. Σ Among them, the active power load P m and active power P of electronic / constant power load e Update the percentage of the first load type ρ m =P m / P Σ The proportion of the second load type ρ e =P e / P Σ .

[0090] Batches that fail verification are not included in the statistics. Load types are primarily obtained from the operation log. When the log is missing, power loads are identified by a significant increase in starting current and reactive power ratio, constant power loads are identified by an approximately constant active power when the voltage changes, and resistive loads are identified by an active power that changes with the square of the voltage.

[0091] S503: Based on the preset base droop coefficients, i.e., the ratio of allowable frequency deviation to rated active power and the ratio of allowable voltage deviation to rated reactive power, linear correction and limiting are performed according to the formula to obtain the current active-frequency droop coefficient and reactive-voltage droop coefficient. The calculation formula is expressed as follows: in, The adjusted active-frequency droop coefficient, i.e. the active-frequency droop gain actually put into use after load characteristic matching, is used for active-frequency regulation in grid-type droop control. As a limiting function, it restricts the input value to a specified upper and lower bound to prevent control instability caused by sudden changes in parameters or changes in sign; The base active power droop factor is set according to the ratio of "allowable frequency deviation to rated active power". Different capacity converters use their respective rated power as the benchmark. The power load active power correction factor is dimensionless and is used to adjust the active power droop factor according to the power load ratio. It is determined by sensitivity simulation or step test. The power load ratio is dimensionless, representing the proportion of active power of the power load that has passed the stability check to the total active power that has been restored. It is a dimensionless active power correction coefficient for power electronic interfaces / constant power loads, used to adjust the active power droop coefficient according to the proportion of constant power load, and is determined by sensitivity simulation or step test. It is the proportion of power electronic interface loads or constant power loads, dimensionless, that is, the proportion of the active power of the power electronic interface or constant power loads that have passed the stability check to the total active power that has been restored; The lower limit of the active power droop factor is set at 0.5. ; The upper limit of the active power droop factor is set to 1.5. ; The adjusted reactive-voltage droop coefficient, i.e., the reactive droop gain actually put into use after load characteristic matching, is used for reactive-voltage regulation in grid-type droop control. The basic reactive power droop factor is set according to the ratio of "allowable voltage deviation to rated reactive power". Different capacity converters use their respective rated power as the benchmark. This is the reactive power correction coefficient for power load, dimensionless, used to adjust the reactive power droop coefficient according to the power load ratio; This is a dimensionless reactive power correction coefficient for power electronic interfaces / constant power loads, used to adjust the reactive power droop coefficient according to the proportion of constant power loads. The lower limit of the reactive power droop factor is set at 0.5. ; The upper limit of the reactive power droop factor is set to 1.5. .

[0092] It should be noted that when the proportion of power load is high, the active power droop slope should be reduced to increase frequency and voltage stiffness; when the proportion of electronic / constant power load is high, the active power channel damping should be appropriately increased and the voltage droop slope reduced to suppress voltage disturbance amplification.

[0093] S504: Supports dynamic power allocation and grid droop coefficient updates using dual time scales. Support power is continuously corrected within a fast control cycle of 1ms. The grid droop coefficient is only updated after the load batch passes stability verification and both the DC voltage change rate and frequency change rate are lower than the preset change rate threshold, such as the frequency change rate not exceeding 0.1Hz / s.

[0094] When the DC voltage change rate, AC frequency change, or converter current approaches the limit, immediately clear the grid parameter update permission flag, maintain the previous set of verified parameters, and prioritize eliminating power deficit through support power correction; after rapid dynamic stabilization, set the permission flag again to update the parameters; the update result is written to the local shared data area, and the dynamic power allocation module re-verifies the preset reserved capacity and the remaining capacity of each support unit accordingly. If the verification is insufficient, the next load batch is blocked.

[0095] Furthermore, in step S500, the smooth exit from the control fault support state and restoration to the normal control mode includes steps S511~S513: S511: When the DC bus voltage and rate of change continuously satisfy... and When the preset recovery criteria are met and the duration reaches the preset recovery time Tr100ms, and there are no pending over-limit flags in the local shared data area, and all deployed batches have passed verification, the state machine transitions from the fault support state to the recovery transition state, and stops adding new load batches.

[0096] S512: The smooth exit process includes first fixing the currently verified active power droop coefficient. and reactive power droop coefficient Next, the active power commands of each non-master control power support unit are gradually reduced according to the preset exit slope.

[0097] It should be noted that the preset exit slope is specifically 50% of the equipment's allowable ramp rate, and is not greater than the ramp rate when support is deployed.

[0098] After the support power drops to the preset residual, i.e., the change in support power does not exceed 2% of the rated power, the flexible interconnection unit in the faulty area will be restored from the network droop control to the normal control mode, such as constant power control.

[0099] Finally, based on the availability status of the original DC voltage master control unit, the DC voltage master control is switched back.

[0100] It should also be noted that the transfer of control adopts an overlapping method, which specifically includes the new main control unit first establishing constant DC voltage regulation and stabilizing the DC voltage, while the original main control unit exits the constant DC voltage mode.

[0101] S513: During the exit process, each stage is at least 100ms apart from the previous stage, and the previous stage's verification is used as the trigger condition; if the voltage, frequency or current exceeds the limit in any stage, the exit is paused or the process is rolled back to the previous stable state.

[0102] Through the above complete process, the system achieves rapid power support after a fault, orderly load recovery, adaptive optimization of network parameters based on actual load characteristics, and a smooth transition back to normal control mode without relying on real-time communication between stations.

[0103] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

[0104] Example 3, referring to Figure 3This is the third embodiment of the present invention. This embodiment provides a power support and grid construction collaborative control system for flexible interconnected photovoltaic and energy storage substations, including a fault perception and discrimination module, a support evaluation and orchestration module, an arbitration and grid construction start-up module, a dynamic power support module, and a verification and recovery management module.

[0105] The fault perception and discrimination module is used to collect and preprocess electrical quantities, establish a local shared data area containing status, events and flags, and use DC voltage and rate of change to judge faults within a preset window, driving the state machine to migrate with hysteresis between normal, pre-switching, support and recovery states.

[0106] The support assessment and orchestration module is used to read data from non-faulty transformer areas in the shared area, calculate the maximum supportable power, compare fault requirements to determine the loads to be cut off and those that can be transferred, and orchestrate batches according to load priority, with the power of each batch not exceeding a preset proportion of the remaining margin.

[0107] The arbitration and network initiation module is used for each candidate unit to autonomously compete for the DC voltage master control based on preset priority and differentiated waiting sequence by locally detecting the DC voltage recovery status. The faulty transformer unit establishes voltage and frequency references according to the limited slope and generates a network ready flag.

[0108] The dynamic power support module is used to determine the initial support power according to the first batch of demand and allocation coefficient before the grid is ready. After the grid is ready, the first batch of power is released synchronously and put into operation with subsequent batches. The support unit corrects the active power command in real time according to the DC voltage deviation and issues it after limiting and rate of change constraints.

[0109] The verification and recovery management module is used to perform multi-dimensional electrical quantity verification after batch deployment, and decide whether to continue, maintain or roll back. It dynamically updates the droop coefficient based on the proportion of the verified load type. After the recovery conditions are met, it sequentially reduces the support increment, switches back the main control, and smoothly exits fault support.

[0110] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

[0111] Example 4, the fourth embodiment of the present invention, differs from the previous three embodiments in that: If the aforementioned functions are implemented as 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 this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0112] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-including system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0113] More specific examples of computer-readable media (a non-exhaustive list) include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0114] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

Claims

1. A method for power support and grid-based coordinated control of flexible interconnected photovoltaic and energy storage distribution areas, characterized in that: include, Perform data acquisition and parameter configuration, establish a local shared data area, and identify faults and control the migration of operating status based on DC bus voltage and rate of change. Calculate the available power for non-faulty transformer areas and schedule load transfer batches; Using preset role competition parameters, each candidate unit autonomously arbitrates and determines the DC voltage master control unit based on the local DC voltage recovery status, performs network soft start for the faulty area, and establishes AC voltage and frequency references; Before the network is ready, the initial support power is determined. After the network is ready, the first batch of loads is released in batches and the subsequent batches are restored in sequence. During the restoration period, the active power command of each non-faulty power support unit is dynamically adjusted according to the change of DC bus voltage. Each batch is checked, and the batch is controlled to continue, maintain or roll back based on the check results. The network droop coefficient is updated according to the proportion of load types that have passed the check. When the recovery conditions are met, the fault support state is smoothly exited and the system is restored to the normal control mode.

2. The method for power support and grid-connected coordinated control of flexible interconnected photovoltaic and energy storage substations as described in claim 1, characterized in that: The fault identification and operation status control migration includes: collecting electrical quantities and storing them in the local shared data area after preprocessing; establishing variables such as status, event, role, capacity, batch, instruction, parameter update permission and over-limit flag in the current data area; and presetting slow-changing parameters locally. The rate of change is calculated using the DC bus voltage. When the voltage and rate of change continuously meet the preset fault criteria within the preset sliding window, the system enters the fault pre-switching state. If the preset confirmation time is exceeded, a fault event flag is generated and the system enters the fault support state. The operating state is switched with hysteresis between normal, fault pre-switch, fault support and recovery transition states according to the preset state transition logic.

3. The method for power support and grid-based coordinated control of flexible interconnected photovoltaic and energy storage substations as described in claim 2, characterized in that: The orchestration of load transfer batches includes reading real-time operating data of each non-faulty station in the local shared data area after detecting a fault event flag; The maximum supportable power is calculated based on the transformer capacity, preset load rate limit, real-time load rate, and power factor of each non-faulty distribution area. Compare the load demand of the faulty transformer area with the sum of the maximum support power of all non-faulty transformer areas to determine the loads that must be cut off, the loads that can be transferred, and the remaining support margin. Load restoration batches are arranged according to the principle of prioritizing the restoration of Category I loads, staggering the peak-hour operation of Category II loads, and dispersing the operation of Category III loads. The restoration power of each batch shall not exceed the preset allocation ratio of the remaining support margin for the current period. Write the load restoration batch and available load information to the local shared data area.

4. The method for power support and grid-connected coordinated control of flexible interconnected photovoltaic and energy storage substations as described in claim 3, characterized in that: The process of performing network soft start and establishing AC voltage and frequency references for the faulty transformer area includes, based on the status information in the local shared data area, reading the pre-stored role competition parameters of each candidate non-faulty unit after entering the fault pre-switching state. Each candidate unit starts a local waiting timer. The highest priority unit that meets the takeover conditions switches to constant DC voltage control mode first. If the DC voltage stops decreasing or starts to rise locally, the remaining candidate units withdraw their takeover requests. If no DC voltage recovery is detected after its own waiting time has ended, the next priority unit will take over and write the final determined DC voltage master control unit role into the local shared data area. The faulty transformer unit establishes AC voltage amplitude and frequency references based on a preset limited slope. When the AC voltage, frequency and converter current are all within the preset allowable range and the preset verification time is reached, a network ready flag is generated and written to the local shared data area.

5. The method for power support and grid-connected coordinated control of flexible interconnected photovoltaic and energy storage substations as described in claim 4, characterized in that: The active power command for dynamically adjusting each non-faulty power support unit includes, before the network readiness flag is generated, reading the first batch of load demand in the local shared data area, calculating the initial support power based on the current demand and estimated loss, and allocating it according to the allocation coefficient obtained by normalization of the maximum support power of each non-faulty unit. Once the network ready flag is set, the initial support power and the first batch of loads will be released synchronously at a preset limited slope. After the support amount reaches the preset ratio of the first batch of demand, the load switch can be closed. Subsequent loads are put into operation in batches. During the current period, the non-faulty unit with the largest transformer capacity maintains the DC voltage stability. The remaining support units calculate and correct the active power command based on the allocation coefficient, DC bus voltage deviation and rate of change, actual output of each unit and remaining capacity. The correction results are issued after being constrained by capacity limit and rate of change.

6. The method for power support and grid-connected coordinated control of flexible interconnected photovoltaic and energy storage substations as described in claim 5, characterized in that: The updated network droop coefficient includes pausing the release of subsequent batches after each batch is deployed, and detecting the DC bus voltage and rate of change, AC voltage and frequency of the faulty transformer area, network unit current and remaining capacity of the support unit within a preset verification period. When all testing volumes are within the allowable range, open the next batch; when a testing volume is close to the limit but has not exceeded the limit, maintain the current batch and increase the output of support units with margin; when any hard limit is exceeded and the preset limit confirmation time continues, cancel the most recently deployed low-priority batch. The faulty transformer unit operates in a droop-based control mode, updating the active droop coefficient and reactive droop coefficient based on the proportion of the first load type and the proportion of the second load type in the verified load batches.

7. The method for power support and grid-connected coordinated control of flexible interconnected photovoltaic and energy storage substations as described in claim 6, characterized in that: The smooth exit from the control fault support state and the return to the normal control mode include the following: when the DC bus voltage and rate of change meet the preset recovery criteria and continue to reach the preset recovery time, and there are no pending over-limit flags in the local shared data area and all the batches that have been put into operation have passed the verification, the system will migrate to the recovery transition state and stop adding new loads. Fix the currently verified active droop coefficient and reactive droop coefficient, and reduce the support command of the non-master control support unit according to the preset exit slope; After the support power drops below the preset residual, the faulty unit will be restored to normal control mode. After confirming that the new DC voltage master control unit has established voltage regulation, switch back the DC voltage master control. The exit from each stage is at least one preset verification period, and the previous stage verification is passed as a condition. If the electrical quantity exceeds the limit in any stage, the exit will be suspended or rolled back.

8. A power support and grid-connection collaborative control system for flexible interconnected photovoltaic and energy storage substations, employing the power support and grid-connection collaborative control method for flexible interconnected photovoltaic and energy storage substations as described in any one of claims 1 to 7, characterized in that, It includes a fault detection and identification module, a support assessment and orchestration module, an arbitration and network startup module, a dynamic power support module, and a verification and recovery management module; The fault perception and discrimination module is used to collect and preprocess electrical quantities, establish a local shared data area containing status, events and flags, and use DC voltage and rate of change to judge faults within a preset window, driving the state machine to migrate with hysteresis between normal, pre-switching, support and recovery states. The support assessment and orchestration module is used to read data from non-faulty transformer areas in the shared area, calculate the maximum supportable power, compare fault requirements to determine the loads to be cut off and those that can be transferred, and orchestrate batches according to load priority, with each batch power not exceeding a preset proportion of the remaining margin. The arbitration and network initiation module is used for each candidate unit to autonomously compete for the DC voltage master control right based on preset priority and differentiated waiting sequence by locally detecting the DC voltage recovery status. The faulty transformer unit establishes voltage and frequency references according to the limited slope and generates a network ready flag. The dynamic power support module is used to determine the initial support power according to the first batch of demand and allocation coefficient before the grid is ready. After the grid is ready, the first batch of power is released synchronously and put into operation with subsequent batches. The support unit corrects the active power command in real time according to the DC voltage deviation and issues it after limiting and rate of change constraints. The verification and recovery management module is used to perform multi-dimensional electrical quantity verification after batch deployment, and decide whether to continue, maintain or roll back. It dynamically updates the droop coefficient based on the proportion of the verified load type. After the recovery conditions are met, it sequentially reduces the support increment, switches back the master control, and smoothly exits fault support.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the power support and network collaborative control method for flexible interconnected distribution areas with optical storage as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the power support and network collaborative control method for flexible interconnected distribution areas with optical storage as described in any one of claims 1 to 7.

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