Railway tunnel fire smoke exhaust control method

Abstract

The application relates to the field of tunnel equipment control and discloses a railway tunnel fire smoke exhaust control method, which comprises the following steps: receiving an alarm trigger signal of a tunnel fire and analyzing the alarm trigger signal to obtain an alarm node identifier; generating a list of to-be-started fans based on a preset tunnel network topology graph; obtaining available power supply currents of current power supply partitions and reading rated starting currents of the fans in the list of to-be-started fans; calculating scheduling priorities of the list of to-be-started fans according to distances between the fans and the alarm node identifier; generating a time-sharing starting queue according to the order from high to low of the scheduling priorities and starting identifiers corresponding to the rated starting currents of the fans being distributed to the fans according to the available power supply currents; wherein, a degradation waiting mark is added to the fans without the starting identifiers; and starting instructions are issued according to the starting queue.

Description

Technical Field

[0001] This application relates to the field of tunnel equipment control, and in particular to a method for controlling smoke exhaust during railway tunnel fires. Background Technology

[0002] With the rapid development of railway transportation networks, railway tunnels, being semi-enclosed, narrow tubular spaces, pose a significant risk of fire. If a train fire occurs inside, the resulting toxic fumes will spread rapidly. Therefore, quickly activating the ventilation fans and jet fan arrays deployed within the tunnel is a crucial means of ensuring personnel evacuation and fire suppression.

[0003] However, the ventilation fans inside the tunnel are heavy inductive loads. At the moment of starting, when the motor accelerates from a standstill to its rated speed, its starting current is often several times higher than the steady-state operating current. When a fire occurs, traditional automated control systems typically employ a one-size-fits-all group control strategy, simultaneously issuing start commands to dozens of fans within the fire zone. However, the maximum available supply current corresponding to the rated capacity of the transformer in the tunnel's power supply zone is fixed. The superimposed starting surge generated by multiple fans starting concurrently can instantly exceed the maximum load capacity of the power supply zone, directly causing a severe voltage drop on the power supply bus, which in turn triggers the overcurrent protection or undervoltage tripping of the feeder cabinet. Once the substation trips, not only will all the fans fail, but the tunnel lighting system will also be cut off.

[0004] Existing technologies limit the maximum number of fans that can be turned on to prevent circuit breakers from tripping. This sacrifices the effective smoke extraction capacity of the smoke exhaust system and fails to maximize the role of the fans in critical situations.

[0005] Solving this technical problem is a technical challenge that needs to be overcome by those skilled in the art. Summary of the Invention

[0006] This application provides a method for controlling smoke exhaust during fires in railway tunnels, which at least partially solves the above-mentioned technical problems.

[0007] To achieve the above objectives, this application provides a method for controlling smoke exhaust in railway tunnel fires, comprising: Receive alarm trigger signals for tunnel fires and analyze them to obtain alarm node identifiers; A list of wind turbines to be started is generated based on a preset tunnel network topology map; Obtain the available power supply current for the current power supply zone and read the rated starting current of each fan in the list of fans to be started; Calculate the scheduling priority of the list of wind turbines to be started based on the distance between each wind turbine and the alarm node identifier; Based on the scheduling priority from high to low and the available power supply current, start flags corresponding to the rated start current are assigned to the wind turbines to generate a time-sharing start queue; among them, a degraded waiting flag is added to the wind turbines that have not been assigned start flags. Start-up commands are issued according to the start-up queue; wherein, when the target wind turbine is detected to have reached the steady-state operating current, the difference current between the rated start-up current and the steady-state operating current is calculated and the difference current is compensated to the available power supply current to trigger the reallocation of wind turbines with degraded waiting flags.

[0008] In this embodiment of the application, the above technical solution improves the technical problem that the huge current surge caused by the concurrent startup of existing wind turbine groups can easily lead to transformer overload tripping and thus cause the overall failure of the smoke exhaust system.

[0009] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a flowchart illustrating the steps of a railway tunnel fire smoke control method provided in an exemplary embodiment of this application. Detailed Implementation

[0012] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0013] This application provides a method for controlling smoke extraction in railway tunnel fires. Please refer to [link / reference]. Figure 1 The method for controlling smoke exhaust in a railway tunnel fire provided in this application includes the following steps: Step 101: Receive the alarm trigger signal of the tunnel fire and parse it to obtain the alarm node identifier.

[0014] Step 102: Generate a list of wind turbines to be started based on the preset tunnel network topology.

[0015] Step 103: Obtain the available power supply current of the current power supply zone and read the rated starting current of each fan in the list of fans to be started.

[0016] Step 104: Calculate the scheduling priority of the list of wind turbines to be started based on the distance between each wind turbine and the alarm node identifier.

[0017] Step 105: Assign start flags corresponding to the rated start current to wind turbines according to the order of scheduling priority from high to low and the available power supply current to generate a time-sharing start queue; among them, add a degraded waiting flag to wind turbines that have not been assigned start flags.

[0018] Step 106: Issue a start command according to the start queue; wherein, when the target wind turbine is detected to have reached the steady-state operating current, calculate the difference current between the rated start current and the steady-state operating current and compensate the difference current to the available power supply current to trigger the reallocation of wind turbines with degraded waiting flags.

[0019] Specifically, it receives fire signals transmitted from the automatic fire alarm system as alarm trigger signals; parses the protocol content to extract the exact zone number of the fire as the alarm node identifier; reads the pre-stored tunnel network topology map; can delineate equipment zones 1.5 kilometers before and after the fire source, extract the fan models within this range to generate a list of fans to be started; accesses the intelligent multi-functional power meter at the tunnel power supply zone feeder cabinet; reads the instantaneous current data of the transformer low-voltage side in real time through the Modbus-TCP communication protocol; calculates and generates the current available power supply current based on the instantaneous current data; reads the rated starting current of each fan in the equipment master data table; and determines the alarm node identifier based on the relationship between each fan and the alarm node identifier. The system calculates the scheduling priority of the list of wind turbines to be started based on distance; it then allocates power according to the scheduling priority from high to low, combined with the remaining available power supply current; for example, it could issue start flags to the first and second wind turbines and store them in a time-sharing start queue; it adds a degraded waiting flag to all wind turbines from the third to the subsequent ones; after the command is issued, it monitors the operating current values ​​of the first two wind turbines; it obtains the steady-state operating current of the first wind turbine after the current peak falls back and remains within the rated range; it calculates the released quota by subtracting the actual consumption from the originally allocated current quota as the differential current and generates an updated available power supply current; based on the updated current margin, it triggers and reallocates start flags to the third wind turbine with the degraded waiting flag.

[0020] This application captures the changes in operating current during the start-up process of the fan and releases the power supply current after entering steady-state operation, thus avoiding insufficient concurrent start-up due to static margin limitations. It enables the sequential start-up of more fans within the target control area without exceeding the maximum load current limit of the transformer, thereby improving the smoke extraction effect.

[0021] In some embodiments, the scheduling priority of the list of wind turbines to be started is calculated based on the distance between each wind turbine and the alarm node identifier, including: Obtain the node connection relationship in the preset tunnel network topology diagram and extract the real-time wind direction parameter corresponding to the alarm node identifier; Based on the real-time wind direction parameters, the node connection relationships are weighted to generate a wind direction weighted topology map; Starting from the alarm node identifier, the weighted path accumulation value to each wind turbine is calculated in the wind direction weighted topology map using the shortest path algorithm; The weighted path summation value is used as the distance; The distance is input into a preset monotonically decreasing priority mapping function for evaluation and calculation to generate the scheduling priority.

[0022] Specifically, the process involves reading a graph structure matrix model representing the tunnel's electromechanical topology; defining each fan's control box as a node and the physical routing of communication and power cables as edges in the graph structure matrix model; obtaining a pre-established mapping table between the fire alarm system's zone codes and the corresponding node identifiers; extracting topology data representing node connections from the matrix; using wind speed sensors configured within the tunnel to obtain the current environment's actual airflow direction and velocity to generate real-time wind direction parameters; combining these real-time wind direction parameters, assigning smaller weight coefficients (e.g., 0.5) to downwind edges and larger weight coefficients (e.g., 2.0) to upwind edges; generating a wind-weighted topology map reflecting the ease of smoke spread; using the node identifier where an alarm occurs as the starting point of the pathfinding function; calling the shortest path algorithm to traverse and expand the wind-weighted topology map; recording and accumulating the weights of the edges required to reach each target fan node, outputting the accumulated weighted path value as a distance; and substituting this distance value into a monotonically decreasing preset priority mapping function to generate the final scheduling priority scalar parameter used for sorting.

[0023] This application uses real-time wind direction parameters to weight the topology network by wind direction, taking into account the asymmetric spread characteristics of fire smoke under different wind directions; it can preferentially allocate limited current quotas to smoke exhaust equipment in downwind areas most severely threatened by smoke, thus improving the efficiency of smoke exhaust control strategies.

[0024] In some embodiments, a time-sharing start-up queue is generated by assigning start-up identifiers corresponding to the rated start-up current to the wind turbines according to the scheduling priority from high to low and the available power supply current, including: The wind turbines in the list of wind turbines to be started are arranged in descending order according to the scheduling priority, and the time-sharing start-up queue is initialized. Select the fans in descending order as the current fans, extract the rated starting current of the current fans, and determine whether the available power supply current is greater than or equal to the rated starting current. When it is determined that the available power supply current is greater than or equal to the rated starting current, the rated starting current is deducted from the available power supply current. Obtain the expected current peak time of the last fan in the time-sharing start-up queue and calculate the staggered delay timestamp of the current fan based on the preset anti-overlap time interval; Associate the staggered delay timestamp with the start identifier and add the associated current wind turbine to the time-sharing start queue.

[0025] Specifically, the process involves: reading a list of wind turbine objects containing priority weights; calling a quicksort algorithm to perform a descending sort operation on the priority field and allocating a blank first-in-first-out data structure in memory to initialize the time-sharing startup queue; sequentially selecting the sorted wind turbine objects as the current wind turbine; reading the rated startup current from its nameplate attributes; comparing this value with the available power supply current; for example, if it is determined that 500 amps is greater than 250 amps and meets the condition; subtracting this value from the available power supply current, thus subtracting 250 amps from 500 amps to generate the latest 250 amps. To mitigate extreme current transients caused by multiple qualified wind turbines starting simultaneously, the system obtains the estimated current peak time of the last wind turbine in the time-sharing start-up queue; reads the anti-overlap time interval pre-stored in the control system; calculates the interleaved delay timestamp of the current wind turbine as the 5th second; associates this 5th second timestamp parameter with a high-level mask representing start permission; generates a start identifier with time attributes and assigns it to the current wind turbine; and adds the associated current wind turbine to the end of the first-in-first-out data structure to be stored in the time-sharing start-up queue.

[0026] By calculating and embedding staggered delay timestamps when allocating starting current, multiple high-efficiency wind turbines will not simultaneously impact the power grid even when there is sufficient residual current, thereby reducing the instantaneous concentrated starting surge and effectively preventing maloperation of transformer differential protection or instantaneous overcurrent protection.

[0027] In some embodiments, adding a degraded waiting flag to wind turbines that have not been assigned a start-up flag includes: When it is determined that the available power supply current is less than the rated starting current, the allocation of the starting identifier is stopped and the remaining unallocated wind turbines under the same scheduling priority are extracted as wind turbines to be downgraded. Calculate the current suppression ratio between the available power supply current and the rated starting current of the fan to be downgraded; Calculate the required delay time of the fan to be downgraded based on the current suppression ratio and generate the slope of the inverter voltage-frequency ratio curve that maps to the current suppression ratio; When the delay time is less than or equal to the preset start time limit, a start identifier is assigned to the wind turbine to be downgraded and a soft start command containing the delay time and the slope of the inverter voltage-frequency ratio curve is issued. When the delay duration exceeds the preset start-up time limit, a degrading wait flag is added to the wind turbine to be degraded and stored in the wait cache area.

[0028] Specifically, the process involves: reading the fan objects in the queue that have not yet been assigned an identifier; reading the rated starting current on their nameplates; comparing the current available power supply current; stopping the starting identifier assignment process and extracting the fan as a fan to be downgraded when the available power supply current is determined to be less than the rated starting current; dividing the available power supply current by the rated starting current to obtain the current suppression ratio; calculating the required extended delay time based on the current suppression ratio and simultaneously looking up the slope of the inverter voltage-frequency ratio curve that is inversely mapped to the current suppression ratio; and reading the thermal resistance of the motor rotor windings of this fan model. The system obtains a preset start-up time limit from the parameters, assigns a start-up identifier to the fan to be downgraded, and sends a slow-start command containing the delay duration and the slope of the adjusted inverter voltage-frequency ratio curve to its underlying inverter via the communication bus; drives the inverter to lengthen the acceleration time and reduce the output voltage, forcibly reducing the peak starting current of the motor to keep it within the range of available power supply current; conversely, if the calculated delay duration is greater than the start-up time limit, it means that if the peak is forcibly reduced, it will cause the motor to overheat and burn out due to low-frequency stall; then a downgrade waiting flag is written into the status field of the fan to be downgraded.

[0029] In some embodiments, when the target wind turbine is detected to have reached its steady-state operating current, the difference current between the rated starting current and the steady-state operating current is calculated, including: Collect the operating current value of the target fan that has received the start command; Construct a sliding time window and calculate the moving average current of the running current values ​​within the sliding time window; The rate of change of current is obtained by calculating the first difference of the moving average current under adjacent sliding time windows; When the rate of change of current is within a preset zero drift band for multiple consecutive sampling periods, the corresponding moving average current is extracted as the actual steady-state operating current and the target wind turbine is determined to have reached a steady-state operating state. The differential current is generated by subtracting the actual steady-state operating current from the rated starting current of the target wind turbine.

[0030] Specifically, the operating current value of the target wind turbine upon receiving the start command is collected; a sliding time window containing several sampling points and stepping with the time axis is constructed, and the moving average current within the window is calculated; the first-order difference between the moving average current of the current time interval and the value of the previous time interval is calculated to obtain the current change rate; for example, when it is determined that the current change rate falls within a preset zero-point drift band of ±0.5 amperes per second for 20 consecutive sampling cycles; it is confirmed that the motor rotor has completely left the acceleration resistance zone, and the moving average current at this time, such as 58 amperes, is extracted as the actual steady-state operating current, and the target wind turbine is determined to have reached a steady-state operating state; the previously reserved rated start current is subtracted from the actual steady-state operating current to generate the differential current.

[0031] In some embodiments, compensating the differential current to the available supply current to trigger a reallocation of power to the wind turbine with a degraded waiting flag includes: Receive the steady-state determination trigger signal for the target wind turbine, and obtain the updated available power supply current based on the differential current and the current remaining available power supply current; The waiting buffer containing wind turbines with downgrade waiting flags is woken up, and the wind turbines are reordered in descending order according to the scheduling priority to generate a compensation candidate queue. Extract the head fan that is at the top of the compensation candidate queue and determine whether the updated available power supply current is greater than or equal to the rated starting current of the head fan. When it is determined that the updated available power supply current is greater than or equal to the rated starting current, a starting flag is issued to the head fan and its degraded waiting flag is removed; The rated starting current of the head fan is subtracted from the updated available power supply current, and the recursive allocation operation of extracting the next fan in order is performed until the updated available power supply current is less than the rated starting current of the currently extracted fan, at which point the allocation stops.

[0032] Specifically, upon receiving a steady-state determination trigger signal for the target wind turbine; the updated available power supply current is obtained by adding the recently recovered ampere difference current to the current remaining available power supply current; a wake-up interrupt is generated to activate all wind turbine objects in the dormant waiting buffer; a sorting algorithm is invoked to reorder the wind turbines in the buffer from largest to smallest according to the previously determined scheduling priority to generate a structured compensation candidate queue; the first wind turbine in the compensation candidate queue is extracted; it is determined whether the updated available power supply current is greater than or equal to the rated starting current of the first wind turbine; if the condition is met, a start flag is issued to the first wind turbine and the status word is modified to remove its downgrade waiting flag; the process returns to extract the next wind turbine in the compensation candidate queue and continues to judge its start requirement with the remaining available power supply current; this recursive allocation operation is executed repeatedly until it is found that the remaining available power supply current is insufficient to meet the rated start requirement of the next extracted wind turbine, at which point a stop command is triggered.

[0033] In some embodiments, the method further includes: Monitor the current time distance to obtain the elapsed duration of the alarm trigger signal; When the elapsed time is greater than or equal to the preset critical smoke exhaust time limit and there are still core smoke exhaust fans in the compensation candidate queue that have not been activated, the tunnel auxiliary loads that are in the on state but are not critical fire protection attributes are disconnected to release available power supply current.

[0034] Specifically, the system monitors the elapsed time since the system initially acquired the alarm trigger signal; when the elapsed time reaches the critical smoke exhaust time limit stipulated in the pre-set fire protection code; the system checks the compensation candidate queue in memory, finds that there are still core smoke exhaust fans in the downwind core protection zone that have not received the start-up indicator, and sends a forced power-off cut-off signal to the contactor coils of non-critical fire protection attribute tunnel auxiliary loads such as the entire line lighting array and tunnel dehumidifier group; releases the large amount of normal power supply current occupied by them and replenishes it to the available power supply current pool to start the core smoke exhaust fan.

[0035] In some embodiments, the method further includes: Monitor the global voltage dips in the power supply zones; When the global voltage sag exceeds a preset safe voltage drop threshold, a delayed allocation signal is generated. Based on the temporary allocation signal, the reallocation of fans with the downgrade waiting mark is intercepted and the newly obtained differential current is frozen until the preset cooling time is reached.

[0036] Specifically, the instantaneous effective value of the line voltage on the power supply bus side of the incoming line cabinet is captured; the percentage difference between the current line voltage and the standard rated voltage is calculated to generate a global voltage sag; the global voltage sag is compared with the preset safe voltage drop threshold set by the safety specifications; when the condition is determined to be met, an interruption flag is generated as a deferred allocation signal; based on the deferred allocation signal, the allocation permission is cut off, and the redistribution of fans with degraded waiting flags is blocked; the updated differential current is locked and suspended until the preset cooling time is reached.

[0037] In some embodiments, after freezing the newly obtained differential current until a preset cooling time is reached, the method further includes: Monitor the power supply voltage recovery slope at the end of the preset cooling period; The temporary allocation signal is released when the supply voltage recovery slope reaches the positive stable range; The frozen differential current will be released for the next round of turbine start-up flag allocation.

[0038] Specifically, at the end of the preset cooling period, a sampled subset of the continuous voltage cycles within that period is retrieved; the least squares method is used to linearly fit the sampled subset data to calculate the power supply voltage recovery slope, which characterizes the voltage change trend; it is determined whether the slope value is greater than zero and whether the fluctuation variance is within the set range; when it is determined that the slope is in the positive stable range, the interruption flag is cleared to release the delayed allocation signal; the lockout state for the frozen differential current is released, and the current quota is released only after ensuring that the power supply network has the ability to withstand the startup surge again, thus ensuring the stability of power supply scheduling.

[0039] In some embodiments, during the process of acquiring the operating current value of the target wind turbine upon receiving the start command, the method further includes: Monitor the duration of continuous acceleration of the target wind turbine after receiving the start command; When the duration of continuous acceleration exceeds the preset limit start-up duration and the target fan has not yet reached a steady-state operating state, it is determined that the target fan has experienced a stall fault. An emergency shutdown command is issued to the target wind turbine that has experienced a stall fault, and its rated starting current is used as the differential current for full release; The protection zone corresponding to the target wind turbine that has stalled is marked as a fault dead zone, and the wind turbine of the second-best level is extracted based on the distance and a compensatory start is performed.

[0040] Specifically, the system monitors the duration of continuous acceleration of the target fan after receiving the start command; when the duration of continuous acceleration exceeds the preset limit start time and the target fan has not yet entered a steady-state operating state according to the preceding slope judgment logic; generates an alarm event code indicating that the motor hardware is stuck or the mechanical air duct is blocked; determines that the target fan has a stall fault; issues the highest priority emergency cut-off command to forcibly disconnect the contactor coil corresponding to the device; extracts the rated start current originally occupied by the device; releases the rated start current as a differential current and fills it back into the global available power supply current pool; marks the zone attribute corresponding to the device as an unavailable fault dead zone in the system topology status table; reads the adjacent zone fan instance objects that are close to the second-best (e.g., with a weighted value); and pushes them into the start queue.

[0041] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0042] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0043] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0044] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A method for controlling smoke extraction in railway tunnel fires, characterized in that, include: Receive alarm trigger signals for tunnel fires and analyze them to obtain alarm node identifiers; A list of wind turbines to be started is generated based on a preset tunnel network topology map; Obtain the available power supply current for the current power supply zone and read the rated starting current of each fan in the list of fans to be started; Calculate the scheduling priority of the list of wind turbines to be started based on the distance between each wind turbine and the alarm node identifier; Based on the scheduling priority from high to low and the available power supply current, start flags corresponding to the rated start current are assigned to the wind turbines to generate a time-sharing start queue; among them, a degraded waiting flag is added to the wind turbines that have not been assigned start flags. Start-up commands are issued according to the start-up queue; wherein, when the target wind turbine is detected to have reached the steady-state operating current, the difference current between the rated start-up current and the steady-state operating current is calculated and the difference current is compensated to the available power supply current to trigger the reallocation of wind turbines with degraded waiting flags.

2. The method according to claim 1, characterized in that, Based on the distance between each wind turbine and the alarm node identifier, the scheduling priority of the list of wind turbines to be started is calculated, including: Obtain the node connection relationship in the preset tunnel network topology diagram and extract the real-time wind direction parameter corresponding to the alarm node identifier; Based on the real-time wind direction parameters, weights are assigned to the connecting edges of the node connection relationships to generate a wind direction weighted topology graph. Starting from the alarm node identifier, the weighted path accumulation value to each wind turbine is calculated in the wind direction weighted topology map using the shortest path algorithm; The weighted path summation value is used as the distance; The distance is input into a preset monotonically decreasing priority mapping function for evaluation and calculation to generate the scheduling priority.

3. The method according to claim 2, characterized in that, Based on the scheduling priority from high to low and the available power supply current, start-up identifiers corresponding to the rated start-up current are allocated to the wind turbines to generate a time-sharing start-up queue, including: The wind turbines in the list of wind turbines to be started are arranged in descending order according to the scheduling priority, and the time-sharing start-up queue is initialized. Select the fans in descending order as the current fans, extract the rated starting current of the current fans, and determine whether the available power supply current is greater than or equal to the rated starting current. When it is determined that the available power supply current is greater than or equal to the rated starting current, the rated starting current is deducted from the available power supply current. Obtain the expected current peak time of the last fan in the time-sharing start-up queue and calculate the staggered delay timestamp of the current fan based on the preset anti-overlap time interval; Associate the staggered delay timestamp with the start identifier and add the associated current wind turbine to the time-sharing start queue.

4. The method according to claim 3, characterized in that, Add a degraded waiting flag to the wind turbines that have not been assigned a start flag, including: When it is determined that the available power supply current is less than the rated starting current, the allocation of the starting identifier is stopped and the remaining unallocated wind turbines under the same scheduling priority are extracted as wind turbines to be downgraded. Calculate the current suppression ratio between the available power supply current and the rated starting current of the fan to be downgraded; Calculate the required delay time of the fan to be downgraded based on the current suppression ratio and generate the slope of the inverter voltage-frequency ratio curve that maps to the current suppression ratio; When the delay time is less than or equal to the preset start time limit, a start identifier is assigned to the wind turbine to be downgraded and a soft start command containing the delay time and the slope of the inverter voltage-frequency ratio curve is issued. When the delay duration exceeds the preset start-up time limit, a degrading wait flag is added to the wind turbine to be degraded and stored in the wait cache area.

5. The method according to claim 4, characterized in that, When the target wind turbine reaches its steady-state operating current, calculate the difference between the rated starting current and the steady-state operating current, including: Collect the operating current value of the target fan that has received the start command; Construct a sliding time window and calculate the moving average current of the running current values ​​within the sliding time window; The rate of change of current is obtained by calculating the first difference of the moving average current under adjacent sliding time windows; When the rate of change of current is within a preset zero drift band for multiple consecutive sampling periods, the corresponding moving average current is extracted as the actual steady-state operating current and the target wind turbine is determined to have reached a steady-state operating state. The differential current is generated by subtracting the actual steady-state operating current from the rated starting current of the target wind turbine.

6. The method according to claim 5, characterized in that, Compensating the differential current to the available supply current to trigger a reallocation of power to the wind turbines with a degraded waiting flag includes: Receive the steady-state determination trigger signal for the target wind turbine, and obtain the updated available power supply current based on the differential current and the current remaining available power supply current; The waiting buffer containing wind turbines with downgrade waiting flags is woken up, and the wind turbines are reordered in descending order according to the scheduling priority to generate a compensation candidate queue. Extract the head fan that is at the top of the compensation candidate queue and determine whether the updated available power supply current is greater than or equal to the rated starting current of the head fan. When it is determined that the updated available power supply current is greater than or equal to the rated starting current of the head fan, a start-up flag is issued to the head fan and its downgrade waiting flag is removed. The rated starting current of the head fan is subtracted from the updated available power supply current, and the recursive allocation operation of extracting the next fan in order is performed until the updated available power supply current is less than the rated starting current of the currently extracted fan, at which point the allocation stops.

7. The method according to claim 6, characterized in that, The method further includes: Monitor the current time distance to obtain the elapsed duration of the alarm trigger signal; When the elapsed time is greater than or equal to the preset critical smoke exhaust time limit and there are still core smoke exhaust fans in the compensation candidate queue that have not been activated, the tunnel auxiliary loads that are in the on state and are non-critical fire protection attributes are disconnected to release available power supply current; the core smoke exhaust fan is a fan located in the downwind defense zone that has not been activated.

8. The method according to claim 7, characterized in that, The method further includes: Monitor the global voltage dips in the power supply zones; When the global voltage sag exceeds a preset safe voltage drop threshold, a delayed allocation signal is generated. Based on the temporary allocation signal, the reallocation of fans with the downgrade waiting mark is intercepted and the newly obtained differential current is frozen until the preset cooling time is reached.

9. The method according to claim 8, characterized in that, After freezing the newly obtained differential current until a preset cooling time is reached, the method further includes: Monitor the power supply voltage recovery slope at the end of the preset cooling period; The temporary allocation signal is released when the supply voltage recovery slope reaches the positive stable range; The frozen differential current will be released for the next round of turbine start-up flag allocation.

10. The method according to claim 9, characterized in that, The method further includes the following steps during the process of acquiring the operating current value of the target wind turbine upon receiving the start command: Monitor the duration of continuous acceleration of the target wind turbine after receiving the start command; When the duration of continuous acceleration exceeds the preset limit start-up duration and the target fan has not yet reached a steady-state operating state, it is determined that the target fan has experienced a stall fault. An emergency shutdown command is issued to the target wind turbine that has experienced a stall fault, and its rated starting current is used as the differential current for full release; The protection zone corresponding to the target wind turbine that has stalled is marked as a fault dead zone, and the wind turbine of the second-best level is extracted based on the distance and a compensatory start is performed.

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