Flood control scheduling method and system for water conservancy hub based on digital twinning

Abstract

The present application relates to the technical field of flood control scheduling, in particular to a water conservancy hub flood control scheduling method and system based on digital twinning. The method obtains a pre-built discharge response sequence set and a wave speed-flow curve; the discharge response sequence set contains a unit response sequence corresponding to each flow level and a reference propagation time; the background flow sequence of the downstream river channel is obtained; for a discharge scheme containing a discharge time and a discharge level, the corresponding unit response sequence and the reference propagation time are taken out according to the discharge level; the actual arrival time is determined by using the wave speed-flow curve; the time length scaling ratio is determined according to the actual arrival time and the reference propagation time; the unit response sequence is processed to generate a corrected response sequence by using the time length scaling ratio; the corrected response sequence is superimposed on the background flow sequence to obtain the downstream total flow sequence, and the cumulative volume is calculated as the risk value, thereby improving the accuracy of the discharge flow calculation.

Description

Technical Field

[0001] This invention relates to the field of flood control scheduling technology, specifically to a flood control scheduling method and system for water conservancy hubs based on digital twins. Background Technology

[0002] Flood control scheduling of water conservancy projects reduces inflow flood peaks through the regulation and storage function of reservoirs, and strives to stagger the discharge process with the confluence flood peaks of downstream tributaries in time, so as to ensure the safety of flood passage in downstream river channels. In scheduling practice, accurately predicting the arrival time of reservoir discharge at each downstream control section is a prerequisite for formulating peak-shaving plans.

[0003] However, the evolution of natural river floods exhibits nonlinear characteristics. The propagation velocity of flood waves dynamically changes with the river flow, and the downstream arrival time of reservoir discharge fluctuates in real time due to the influence of background water flow. Currently, existing technologies typically use fixed lag times or the linear Muskingan method to estimate the flood arrival time. This approach ignores the nonlinear mechanism of wave velocity changes with flow field intensity. For example, during the flood season with large-volume discharges or when the downstream bottom water level is high, the actual flood wave velocity is often significantly faster than the baseline wave velocity during the dry season, causing the flood head to arrive downstream earlier than expected. Therefore, if peak staggering operations are carried out based on fixed-time estimations, it may lead to two high-flow-volume water heads unexpectedly meeting at the same time, causing flood peak superposition and exacerbating downstream flood control pressure. Summary of the Invention

[0004] To address the technical problem of inaccurate flood evolution time prediction in existing flood control scheduling methods, which leads to the failure of peak-shaving scheduling, this invention provides a flood control scheduling method and system for water conservancy hubs based on digital twins. The specific technical solution adopted is as follows: This invention proposes a flood control scheduling method for water conservancy projects based on digital twins, the method comprising: Obtain the pre-built set of discharge response sequences and wave velocity-discharge curves; the set of discharge response sequences includes the unit response sequence and reference propagation time corresponding to each flow level. The unit response sequence consists of flow increments arranged in relative time order, and the reference propagation time is the time from the discharge to the start of flow increase downstream; the wave velocity-discharge curve represents the functional relationship between the flow rate and wave velocity at the river cross-section. Obtain the background flow sequence of the downstream river channel, which consists of natural flow values ​​at each time point arranged in chronological order; For a discharge scheme that includes the discharge start time and discharge level, the corresponding unit response sequence and reference propagation time are extracted based on the discharge level; the actual arrival time is determined by segmented velocity integration using the wave velocity-flow curve; The duration scaling ratio is determined based on the actual arrival time and the reference propagation time; the duration scaling ratio is used to scale the unit response sequence on the time axis and compensate for the amplitude to generate a corrected response sequence. The corrected response sequence is superimposed on the background flow sequence to obtain the downstream total flow sequence. The cumulative volume of flow exceeding the safety threshold at each time point in the sequence is counted as the risk value. Among the discharge schemes with a risk value of zero, the scheme with the largest total discharge volume is selected as the optimal discharge trajectory, and the gate control signal is output.

[0005] Furthermore, the set of leakage response sequences adopts a unified time step, and the unit response sequence corresponding to each flow level consists of flow increments arranged in time step order; where k represents the number of time steps elapsed since the leakage was issued, k is an integer greater than or equal to 0, and the kth value in the unit response sequence represents the flow increment generated downstream at the kth time step after the leakage was issued; the reference propagation time is the number of time steps elapsed from the issuance of the leakage to the start of flow increase downstream.

[0006] Furthermore, the pre-construction process of the discharge response sequence set includes: Based on the reservoir water level-discharge capacity relationship curve, the minimum and maximum discharge capacities of the reservoir are determined, and the discharge capacity range is statistically obtained. The discharge capacity range is then discretized into multiple flow levels according to a preset flow step size. The low-water base flow value is determined based on historical hydrological data of the downstream river channel. A one-dimensional hydrodynamic model was constructed based on measured cross-sectional topographic data of the downstream river channel, and the parameters of the one-dimensional hydrodynamic model were calibrated using typical flood data. The boundary conditions of the one-dimensional hydrodynamic model were set to the low-water baseflow value, and the model was run until it reached a steady state across the entire river section. For each flow rate, a rectangular flow pulse with an amplitude equal to that flow rate and lasting for one time step was applied to the upstream boundary. Starting from the pulse emission moment, the downstream cross-sectional flow value is recorded step by step according to a unified time step. The low-water base flow value is subtracted from the downstream cross-sectional flow value at each time step to obtain the flow increment at the corresponding time step. The flow increments of all time steps are arranged in chronological order to form the unit response sequence for this flow level. Starting from the pulse emission moment, the flow increment of the downstream cross-section is checked step by step. The moment when the flow increment first exceeds zero is recorded as the rise time. The number of time steps between the rise time and the pulse emission moment is counted as the reference propagation time for this flow level. All flow rate levels are associated with and stored along with the baseline propagation time to form a flow discharge response sequence set.

[0007] Furthermore, the wave velocity-flow rate curve is constructed offline through the following steps: In a one-dimensional hydrodynamic model, a series of steady-state background flows are set in a stepped increasing manner; wherein, the series of steady-state background flows covers the range of flows from the low-water flow value to the design flood flow value; and each steady-state background flow is used as the upstream boundary condition of the one-dimensional hydrodynamic model until the entire river section reaches a steady state; For each steady-state background flow, after the model reaches a steady state under the steady-state background flow, a small perturbation wave is applied to the upstream boundary based on the steady state; wherein the amplitude of the perturbation wave is a preset percentage of the steady-state background flow and lasts for one time step; The time when the peak of the disturbance wave passes through the upstream section is recorded as the upstream peak time, and the time when the disturbance wave passes through the downstream control section is recorded as the downstream peak time. The time step difference between the downstream peak time and the upstream peak time is calculated as the propagation time. The average wave velocity under steady-state background flow is obtained by dividing the total length of the river channel by the propagation time. The total length of the river channel is used to indicate the distance between the upstream section and the downstream control section. The steady-state background flow rate and the corresponding average wave velocity are paired, and the wave velocity-flow rate curve is obtained by power function regression fitting. Set a preset minimum wave velocity threshold for the wave velocity-flow curve; if the wave velocity obtained by querying the wave velocity-flow curve is less than the preset minimum wave velocity threshold, the preset minimum wave velocity threshold will be forcibly used as the query result.

[0008] Furthermore, the process of obtaining the background flow sequence includes: Access the gridded rainfall forecast data released by the meteorological department to obtain the predicted rainfall values ​​for each grid unit in the forecast area at each future time step; Using a pre-built and calibrated interval hydrological model, the rainfall forecast values ​​of each grid cell are converted into runoff, and then combined according to the watershed outlet to obtain the runoff sequence of each time step in the downstream interval. The river confluence calculation method is used to calculate the flow sequence of each tributary along the river channel to the downstream control section, and obtain the natural flow value at each time step at the downstream control section. The natural flow values ​​at each time step are arranged in time step order to form a background flow sequence. The background flow sequence uses the same time steps as the discharge response sequence set. The values ​​in the background flow sequence are arranged in time step order, with i representing the time step number. i is a positive integer greater than or equal to 1. The i-th value in the background flow sequence represents the natural flow value of the downstream channel at the i-th time step.

[0009] Furthermore, the actual arrival time acquisition process includes: Initialize the cumulative propagation distance to zero, and set the current time step to the time step number corresponding to the moment the leakage was emitted; Repeated iterative calculations are performed until the cumulative propagation distance reaches or exceeds the total length of the river channel. The iterative calculation includes the following steps: using preset weighting coefficients, the natural flow values ​​at the upstream and downstream sections of the current time step are weighted and averaged to obtain the characteristic flow for the current time step; the downstream natural flow value is obtained from the baseline flow sequence, and the upstream natural flow value is obtained from upstream hydrological forecast data; the characteristic flow is added to the flow value corresponding to the discharge level to obtain the equivalent flow; the wave velocity-flow curve is queried using the equivalent flow to obtain the instantaneous wave velocity for the current time step; the instantaneous wave velocity is multiplied by the time step length to obtain the propagation distance increment for the current time step, which is accumulated to the cumulative propagation distance; the current time step is incremented by one time step to proceed to the next time step. If the cumulative propagation distance reaches or exceeds the total length of the river channel, the current time step is taken as the actual arrival time of the flood wave head.

[0010] Furthermore, the process of determining the duration scaling ratio includes: Subtract the time step number corresponding to the leakage emission time from the time step number corresponding to the actual arrival time to obtain the number of time steps between the two, which is the actual propagation time. Divide the retrieved baseline propagation time by the actual propagation time to obtain the duration scaling ratio of the leakage scheme.

[0011] Furthermore, the step of scaling the unit response sequence on the time axis and compensating for amplitude using a time-scaling ratio to generate a corrected response sequence includes: Divide the time axis length of the unit response sequence by the duration scaling ratio to obtain the time axis length after scaling. The traffic increment at each time step in the unit response sequence is multiplied by the duration scaling ratio to obtain the amplitude-compensated traffic increment; wherein, the time axis scaling and amplitude compensation are performed simultaneously. The scaled and compensated sequence is used as the starting point of the time axis to obtain the corrected response sequence; the corrected response sequence starts from the time step corresponding to the actual arrival time, and each time step corresponds to a flow increment after amplitude compensation.

[0012] Furthermore, the risk value determination process includes: Starting from the time step corresponding to the actual arrival time, the corrected response sequence is aligned with the background flow sequence by time step and then added step by step to obtain the downstream total flow value at the same time step; where the time step not covered by the corrected response sequence is directly taken as the value of the corresponding time step of the background flow sequence as the downstream total flow value. Arrange the downstream total flow values ​​at each time step in the order of time steps to obtain the downstream total flow sequence; The downstream total flow value at each time step in the downstream total flow sequence is compared with a preset safety threshold. If the downstream total flow value is greater than the preset safety threshold, the difference between the downstream total flow value and the preset safety threshold is calculated as the excess flow value. The excess flow value is multiplied by the time step to obtain the excess volume at the corresponding time step. If the total downstream flow is less than or equal to the preset safety threshold, the excess volume at the corresponding time step will be set to zero. By summing up the excess volume of all time steps, the risk value of the leakage scheme is obtained.

[0013] A flood control scheduling system for a water conservancy hub based on digital twins, the system comprising a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor executes the computer program to implement the steps of a flood control scheduling method for a water conservancy hub based on digital twins.

[0014] The present invention has the following beneficial effects: This invention pre-constructs a set of discharge response sequences containing multiple flow levels and fits them to obtain a wave velocity-flow curve characterizing the relationship between flow and wave velocity. This breaks free from the limitations of fixed propagation parameters, allowing for the combination of leveled unit response sequences and baseline propagation time to provide standardized data support for flood propagation calculations under different discharge scales, adapting to complex river hydraulic change scenarios. By obtaining the time-series background flow sequence of the downstream river channel, it is possible to accurately reconstruct the temporal variation characteristics of natural inflow formed by rainfall runoff and tributary confluence. By combining artificial discharge with the natural inflow of the basin, it avoids calculation distortion caused by considering only the discharge flow and improves the realism of global flow projection. For different discharge schemes, it matches the data of the corresponding level and performs segmented flow velocity integral calculation of the actual arrival time by combining the wave velocity-flow curve. This fully considers the dynamic impact of flow changes along the route on wave velocity, overcomes the error problem of fixed propagation time calculation, and accurately characterizes the actual evolution law of the discharge flood wave. Attached Figure Description

[0015] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the 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.

[0016] Figure 1 A flowchart of a flood control scheduling method for a water conservancy hub based on digital twins is provided in one embodiment of the present invention; Figure 2 This is an example diagram illustrating the actual arrival time acquisition process provided in one embodiment of the present invention. Detailed Implementation

[0017] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a water conservancy hub flood control scheduling method and system based on digital twins proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0019] The following description, in conjunction with the accompanying drawings, details a specific scheme for a water conservancy hub flood control scheduling method and system based on digital twins provided by this invention.

[0020] Please see Figure 1 The diagram illustrates a flowchart of a flood control scheduling method for a water conservancy hub based on digital twins, according to an embodiment of the present invention. The method includes: S101: Obtain the pre-built set of discharge response sequences and wave velocity-flow curves; the set of discharge response sequences includes the unit response sequence and reference propagation time corresponding to each flow level. The unit response sequence consists of flow increments arranged in relative time order, and the reference propagation time is the time from the discharge to the start of flow increase downstream; the wave velocity-flow curve represents the functional relationship between the flow rate and wave velocity at the river cross-section.

[0021] It is important to understand that this invention is applied to the flood control scheduling scenario of a water conservancy project. An example of a flood control scheduling scenario is as follows: the water conservancy project is located upstream of a river, and a flood discharge gate is installed at the project site. The downstream flow is regulated by controlling the opening of the gate. There are several control sections along the downstream river, among which the most important control sections are usually located at downstream towns, important infrastructure, or confluences with tributaries.

[0022] It should be noted that this method uses the location of the reservoir's flood discharge gate as the upstream section and the downstream location that needs to be protected (determined by the actual engineering situation) as the downstream control section. The river length between the upstream section and the downstream control section is the flood propagation distance.

[0023] The spillway response sequence set and wave velocity-flow curve are both pre-built through offline pre-calculation and can be directly called and used later.

[0024] As a preferred implementation, the discharge response sequence set adopts a unified time step, and the unit response sequence corresponding to each flow level consists of flow increments arranged in time step order; where k represents the number of time steps elapsed since the discharge was issued, k is an integer greater than or equal to 0, and the k-th value in the unit response sequence represents the flow increment generated downstream at the k-th time step after the discharge was issued; the reference propagation time is the number of time steps elapsed from the discharge to the downstream flow starting to increase.

[0025] A flow rate level is a set of discrete flow rate values ​​obtained by discretizing the continuous discharge capacity of a reservoir at a fixed step size. Each flow rate level corresponds to a pre-stored unit response sequence and a reference propagation time.

[0026] The unit response sequence records the flow increment generated at each time step of the downstream control section when flood discharge is carried out at a certain flow level.

[0027] The baseline propagation time records the number of time steps from the discharge point to the point where the downstream flow begins to increase.

[0028] Relative time order refers to a timeline starting from the instant the discharge is emitted. The values ​​in the unit response sequence are arranged according to this timeline, with the first value corresponding to the instant the discharge is emitted (i.e., the 0th time step after the discharge is emitted), and subsequent values ​​corresponding to the first time step, the second time step, and so on, after the discharge is emitted.

[0029] Since there is no downstream response immediately after the discharge is initiated, the flow increment is 0. Therefore, the starting index of k is set to 0, where k=0 represents the 0th time step after the discharge is initiated, i.e., the starting point relative to the time axis.

[0030] It should be noted that the specific value of the time step can be determined based on the rate of change of the flood wave and the required scheduling accuracy; this embodiment does not impose a specific limitation. For example, if the time step is set to 15 minutes, then the first time step represents 0-15 minutes, the second time step represents 15-30 minutes, and so on.

[0031] It should be noted that the time step is an ordinal number (e.g., the 1st, 2nd, etc.), and the time step length is the actual time length corresponding to each time step (e.g., 15 minutes). The actual time is obtained by multiplying the time step and the time step length. All time-related calculations in this invention are performed in units of time steps.

[0032] The process of pre-building the discharge response sequence set includes the following steps: 1) Based on the reservoir water level-discharge capacity relationship curve, determine the minimum and maximum discharge capacity of the reservoir and statistically obtain the discharge capacity range; discretize the discharge capacity range into multiple flow levels according to the preset flow step size; determine the low-water base flow value based on the historical hydrological data of the downstream river channel.

[0033] The water level-discharge capacity curve describes the maximum flow rate that a reservoir's spillway structures (such as gates and spillways) can handle at different water levels. This data is typically determined by hydraulic model tests or design data and is standard basic data for water conservancy projects; it can be directly applied in this embodiment.

[0034] It should be noted that the preset flow step size is the flow interval between adjacent flow levels, and its specific value can be determined based on engineering experience; this embodiment does not impose a specific limitation. For example, the preset flow step size is typically 100-200. / s is used as the preset traffic step size, for example, the preset traffic step size is 100. / s.

[0035] Historical hydrological data consists of long-term accumulated water level and flow observation records from hydrological stations. This is existing technology and can be directly applied in this embodiment. Specifically, the low-water baseflow value is typically taken as the multi-year average low-water flow or the daily average flow under a 90% guarantee rate. The low-water baseflow value represents the typical low-flow state of the river channel during the dry season.

[0036] 2) A one-dimensional hydrodynamic model was constructed based on the measured cross-sectional topographic data of the downstream river channel, and the parameters of the one-dimensional hydrodynamic model were calibrated using typical flood data.

[0037] It should be noted that the river channel geometric model was established based on measured cross-sectional topographic data, and the Saint-Venant equations were used to describe the water flow. Parameters such as the roughness coefficient were adjusted by back-calculating typical flood data to ensure that the calculated values ​​of the one-dimensional hydrodynamic model match the measured values. The establishment of a one-dimensional hydrodynamic model is a standard technique in hydraulics and will not be elaborated upon here.

[0038] 3) Set the boundary conditions of the one-dimensional hydrodynamic model to the low-water baseflow value and run it until the whole river reaches a steady state; for each flow level, apply a rectangular flow pulse with an amplitude equal to that flow level and a duration of one time step at the upstream boundary.

[0039] Set the model boundary conditions to the low-water baseflow value and run it for a sufficient time until the water level and flow velocity at each cross-section no longer change with time; this is called steady state. This is standard operation for hydrodynamic models and is known to those skilled in the art.

[0040] 4) Starting from the pulse emission time, record the downstream cross-sectional flow value step by step according to a unified time step. Subtract the low water base flow value from the downstream cross-sectional flow value at each time step to obtain the flow increment at the corresponding time step. Arrange the flow increments of all time steps in chronological order to form the unit response sequence of the flow range. Starting from the pulse emission time, check the flow increment of the downstream cross-section step by step. Record the moment when the flow increment is first greater than zero as the rise time. Count the number of time steps between the rise time and the pulse emission time as the reference propagation time of the flow range.

[0041] Since it is necessary to extract the response waveform generated downstream when each flow rate is applied individually, a rectangular flow pulse with constant amplitude and duration of one time step is applied at the upstream boundary as a standardized excitation signal so that the response waveform generated downstream can uniquely correspond to the flow rate.

[0042] An example of the process for obtaining the downstream cross-sectional flow value at each time step is as follows: By running a one-dimensional hydrodynamic model, the model calculates the propagation process of the water flow along the river channel step by step using the Saint-Venant equations based on the upstream boundary conditions and parameters, and automatically outputs the downstream cross-sectional flow value at each time step of the downstream control section. It should be noted that the above process of obtaining the downstream cross-sectional flow value is a standard output function of the hydrodynamic model and belongs to existing technology; this embodiment can be directly applied.

[0043] The flow increment refers to the flow value at the downstream section when there is a discharge pulse minus the flow value at the downstream section when there is no discharge (i.e., the low-water base flow value), representing the additional flow generated solely by the discharge pulse.

[0044] The moment of the initial rise indicates that the flood wave has reached the downstream section.

[0045] 5) Store the unit response sequence and reference propagation time of all flow rates together to form a flow discharge response sequence set.

[0046] It is important to understand that the propagation speed of flood waves typically increases with the increase of river cross-sectional flow, and the wave velocity exhibits a non-linear relationship under different flow rates. Therefore, in order to quickly query the corresponding instantaneous wave velocity based on real-time flow conditions, it is necessary to pre-construct a wave velocity-flow curve, quantifying the mapping relationship between flow rate and wave velocity as a function curve.

[0047] The wave velocity-flow rate curve is constructed offline through the following steps: 1) In the one-dimensional hydrodynamic model, a series of steady-state background flows are set in a step-by-step increasing manner; the series of steady-state background flows covers the range of flows from the low water flow value to the design flood flow value; and each steady-state background flow is used as the upstream boundary condition of the one-dimensional hydrodynamic model until the entire river section reaches a stable state.

[0048] Because the propagation speed of flood waves varies with the flow rate, wave velocities need to be measured at different flow levels to establish a complete flow-wave velocity function relationship. Therefore, a series of steady-state background flow rates are set in a stepped increasing manner, starting from the low-water flow rate and gradually increasing to exceed the design flood flow rate, covering the entire flow range that may occur in the river channel.

[0049] For example, a stepped increase refers to starting from the low water flow value and gradually increasing it at fixed flow intervals until it exceeds the design flood flow. Assuming the low water flow value is 500... / s, then from 500 Starting at / s, incrementing by 500 each time. The flow rate is set to 500, 1000, 1500, 2000... in sequence until it exceeds the design flood flow rate. The flow rate interval can be adjusted according to the accuracy requirements, and this embodiment does not impose a specific limitation.

[0050] It should be noted that the design flood discharge is calculated based on the importance and design standards of the downstream protected objects, usually through hydrological frequency analysis, and is a fundamental parameter in hydraulic engineering design. For example, the design flood discharge for a certain river during a 100-year period is 10,000 cubic meters per second. / s.

[0051] It should be noted that "running until the entire river section reaches a stable state" here refers to the steady flow state at each cross-section, inferred through numerical simulation using a one-dimensional hydrodynamic model, where the hydraulic elements no longer change with time, rather than waiting on-site and knowing it through a one-dimensional hydrodynamic model.

[0052] 2) For each steady-state background flow, after the model reaches a steady state under the steady-state background flow, a small perturbation wave is applied to the upstream boundary based on the steady state; wherein the amplitude of the perturbation wave is a preset percentage of the steady-state background flow and lasts for one time step.

[0053] A disturbance wave is a rectangular flow pulse with a small amplitude that lasts for one time step. Specifically, based on the steady-state background flow, the flow instantaneously increases by a tiny amount (e.g., 1% of the steady-state background flow), lasts for one time step, and then instantly returns to its original value.

[0054] It should be noted that the specific value of the preset percentage can be determined based on engineering practice experience, and this embodiment does not impose a specific limitation. For example, the preset percentage is usually between 1% and 5%.

[0055] 3) Record the time when the peak of the disturbance wave passes through the upstream section as the upstream peak time, and the time when the disturbance wave passes through the downstream control section as the downstream peak time; calculate the time step difference between the downstream peak time and the upstream peak time as the propagation time; divide the total length of the river channel by the propagation time to obtain the average wave velocity under steady-state background flow; where the total length of the river channel is used to indicate the distance between the upstream section and the downstream control section.

[0056] It should be noted that the flow process lines at each cross-section output by the one-dimensional hydrodynamic model provide a clear visual representation of the spikes generated when the disturbance wave passes through. Specifically, by utilizing the post-processing function of the one-dimensional hydrodynamic model to search for the maximum value and its occurrence time in the flow process lines at each cross-section, the times when the disturbance wave peak passes through the upstream cross-section (i.e., the upstream peak time) and the times when the disturbance wave passes through the downstream control cross-section (i.e., the downstream peak time) can be obtained. Searching for the flow process lines at each cross-section using the one-dimensional hydrodynamic model is a standard function of hydrodynamic models and is existing technology, so it will not be elaborated upon here.

[0057] The total length of a river channel refers to the length of the river's centerline from the upstream section (i.e., the location of the reservoir's floodgate) to the downstream control section. This length can be directly obtained through measured topographic data or a river GIS system. It should be noted that obtaining the total length of a river channel is a conventional method in water conservancy engineering, and this embodiment can apply it directly.

[0058] 4) The steady-state background flow rate and the corresponding average wave velocity are paired to form a data pair, and the wave velocity-flow rate curve is obtained by power function regression fitting.

[0059] Because there is a nonlinear positive correlation between flood wave propagation velocity and cross-sectional discharge, and numerous experimental and theoretical studies have shown that they conform to a power function law, belonging to the standard regression method among existing numerical analysis methods, a power function form is used to perform regression fitting on the data pair. For example, the wave velocity-discharge curve can be expressed in power function form as: v Where Q is the cross-sectional flow rate, v is the corresponding wave velocity, and a, b, and c are the parameters to be fitted. The exponent of the flow rate term in the curve must be greater than zero, i.e., b must be greater than zero, to ensure that the larger the flow rate, the faster the wave velocity.

[0060] 5) Set a preset minimum wave velocity threshold for the wave velocity-flow curve; if the wave velocity obtained by querying the wave velocity-flow curve is less than the preset minimum wave velocity threshold, the preset minimum wave velocity threshold will be forcibly used as the query result.

[0061] It should be noted that the specific value of the preset minimum wave velocity threshold is usually taken as the measured wave velocity value under low water flow conditions; this embodiment does not impose a specific limitation. For example, a low water flow of 500... If the measured wave velocity is 0.5 m / s, then the minimum wave velocity threshold can be set to 0.5 m / s.

[0062] S102: Obtain the background flow sequence of the downstream river channel. The background flow sequence consists of the natural flow values ​​at each time point arranged in chronological order.

[0063] It's important to understand that the flood wave generated by reservoir discharge needs to be superimposed on the natural inflow of the downstream river channel to accurately assess whether the flow at the downstream section exceeds the safety threshold. Therefore, it is also necessary to obtain the background flow sequence of the downstream river channel. The background flow sequence can usually be obtained based on gridded rainfall forecast data, by converting rainfall into runoff using an interval hydrological model (such as the Xin'anjiang model), and then by river confluence calculation. These hydrological forecasting techniques are conventional and can be applied directly.

[0064] The natural inflow into the downstream channel refers to the water volume that flows into the downstream channel from the upstream basin and its tributaries when the reservoir does not release water (or there is no reservoir intervention). This inflow mainly originates from rainfall runoff within the basin and is influenced by factors such as topography, soil, and vegetation; it represents the natural flow value of the river channel itself. In this scheme, the baseline flow sequence is the natural inflow value for each future time step predicted through rainfall forecasting and hydrological models, and is referred to as the "natural flow value".

[0065] Since flood control scheduling typically requires forecasting and planning for flood events over a future period, this plan also sets a pre-defined forecast period to ensure that the spillway scheme covers the entire process from the present to key future periods. The forecast period refers to the time frame that needs to be planned in advance for decision-making regarding the spillway scheme.

[0066] Specifically, starting from the current time, only the natural flow values ​​of each time step within the preset forecast period are calculated; time steps exceeding the forecast period are not calculated. For example, if the current time is 8:00 AM, the time step is 15 minutes, and the preset forecast period is set to 24 hours (i.e., 96 time steps), then the background flow sequence only includes the natural flow values ​​of the 1st to the 96th time steps; the 97th time step and beyond are not calculated.

[0067] It should be noted that the specific value of the preset forecast period can be determined comprehensively based on the watershed area and meteorological forecasting capabilities; this embodiment does not impose a specific limitation. For example, it could be 24 hours or 72 hours in the future.

[0068] To prevent flood waves from propagating in the river channel beyond the forecast period (especially during low-flow discharges), the waveform tails will be truncated without a buffer period, affecting the accuracy of risk values. Therefore, when generating the baseline flow sequence, it is necessary to determine whether to add a buffer period. Specifically, obtain the baseline propagation time for all flow levels in the discharge response sequence set and find the maximum baseline propagation time. If the number of time steps corresponding to the maximum baseline propagation time is less than or equal to the number of time steps included in the preset forecast period, then the waveforms for all flow levels can be completely covered within the preset forecast period, and no additional buffer period is needed. If the maximum baseline propagation time is greater than the number of time steps included in the preset forecast period, then a buffer period needs to be added to the preset forecast period.

[0069] It should be noted that the buffer duration should be greater than the difference between the maximum reference propagation time and the number of time steps of the forecast period, and is usually a preset multiple of the maximum reference propagation time. For example, the buffer duration is 1.5 times the maximum reference propagation time.

[0070] The process of obtaining the background flow sequence includes the following steps: 1) Access the gridded rainfall forecast data released by the meteorological department to obtain the rainfall forecast values ​​for each grid unit in the forecast area at each time step in the future.

[0071] 2) Using a pre-built and calibrated interval hydrological model, the predicted rainfall values ​​of each grid cell are converted into runoff, and then combined according to the watershed outlet to obtain the runoff sequence of each time step in the downstream interval.

[0072] It should be noted that the gridded rainfall forecast data is publicly released by the meteorological department and can be directly accessed and used. Inter-regional hydrological models (such as the Xin'anjiang model) are mature models widely used in the field of hydrology, and their construction and calibration methods are publicly available technologies. This solution directly utilizes the aforementioned existing technologies and data without involving any changes to their internal principles, conforming to industry practice and possessing technical rationality.

[0073] 3) Using the river confluence calculation method, the flow sequence of each tributary is calculated along the river channel to the downstream control section to obtain the natural flow value at each time step at the downstream control section.

[0074] It should be noted that river runoff calculation is a routine technique in hydrology, with commonly used methods including the Muskingan method, isochrone method, and unit hydrograph method. Specifically, these methods simulate the propagation process of runoff in the river channel, taking into account the regulating effect of water flow and propagation delay, to calculate the time and flow rate of runoff from the upstream or tributary to the downstream control section. This allows the determination of the natural flow rate at each time step at the downstream control section. This scheme directly adopts the aforementioned mature methods.

[0075] 4) Arrange the natural flow values ​​of each time step in the order of time steps to form a background flow sequence; wherein, the background flow sequence adopts the same time steps as the discharge response sequence set, the values ​​in the background flow sequence are arranged in the order of time steps, i represents the time step number, i is a positive integer greater than or equal to 1, and the i-th value in the background flow sequence represents the natural flow value of the downstream river channel at the i-th time step.

[0076] The background flow sequence describes the natural flow value on an absolute time axis, starting from the current moment. The first time step (i=1) represents the first time step after the current moment, so the index starts from 1. The unit response sequence, on the other hand, describes the response process on a relative time axis, starting from the instant the discharge is emitted (k=0), representing the state immediately after the discharge is emitted, so the index starts from 0. The two sequences have different starting points and serve different time reference systems.

[0077] Absolute Time Axis: A time axis that starts from the current moment and extends forward in time step order. It is used to describe quantities related to the actual time process, such as the background flow sequence and the time of discharge. The time step number i on the absolute time axis starts from 1, i=1 represents the first time step after the current moment, i=2 represents the second time step, and so on.

[0078] In contrast, the relative time axis, starting from the instant the discharge occurs, describes the unit response sequence. The time step number k on the relative time axis starts from 0, where k=0 represents the instant the discharge occurs, k=1 represents the first time step after the discharge occurs, and so on.

[0079] The conversion relationship between the two is as follows: the kth time step on the relative time axis corresponds to the (leakage emission time + k)th time step on the absolute time axis.

[0080] For example, assuming the current time is 8:00 AM and the time step is 15 minutes, then in the background flow sequence, i=1 corresponds to 8:15, i=2 corresponds to 8:30, and so on; while in the unit response sequence, k=0 corresponds to the instant the discharge is initiated (assuming the discharge starts at 8:15), k=1 corresponds to 15 minutes after the discharge is initiated (i.e., 8:30), and k=2 corresponds to 8:45.

[0081] S103: For a discharge scheme that includes the discharge emission time and discharge level, extract the corresponding unit response sequence and reference propagation time according to the discharge level; use the wave velocity-flow curve to perform piecewise velocity integration to determine the actual arrival time.

[0082] The discharge plan includes a pair of parameters: the discharge initiation time and the discharge level. The discharge initiation time refers to the planned time step number on the absolute timeline to begin discharge (e.g., the 10th time step), and the discharge level refers to the planned discharge flow rate (e.g., 500). ( / s), which means that a discharge scheme corresponds to a specific discharge time and a specific discharge level.

[0083] It's important to understand that the discharge threshold in the discharge scheme is used to match flow thresholds with equal values ​​in the discharge response sequence set, and to extract the unit response sequence and reference propagation time corresponding to that flow threshold. The discharge emission time in the discharge scheme is used to determine the alignment between the relative time axis and the absolute time axis.

[0084] Since the unit response sequence and reference propagation time for each tier are pre-calculated offline, the tiers in the bleed flow scheme must be selected from the pre-stored set of flow tiers in the bleed flow response sequence set (e.g., 100, 200, 300). / s), and arbitrary intermediate values ​​cannot be used. However, if an intermediate flow value is required for actual scheduling, it can be approximated by linear interpolation of adjacent flow levels, or by reducing the flow interval between adjacent levels when dividing flow levels, thereby increasing the number of flow levels. For example, if the original flow interval is 100... / s, with traffic tiers of 100, 200, 300...; encrypt the traffic interval to 50. After / s, the flow rate levels change to 100, 150, 200, 250, 300..., thereby improving accuracy.

[0085] For example, a certain discharge scheme sets the discharge activation time to the 10th time step, and the discharge level to 500. / s, then the flow rate level 500 is taken from the effluent response sequence set. / s corresponds to the unit response sequence, where k=0 (relative starting point) corresponds to the 10th time step on the absolute time axis, k=1 corresponds to the 11th time step, and so on.

[0086] The process of obtaining the actual arrival time is as follows: Figure 2 As shown, it includes: S103-1: Initialize the cumulative propagation distance to zero and set the current time step to the time step number corresponding to the time of the leakage emission.

[0087] It's important to understand that when actually developing a discharge plan, the discharge emission time might be any arbitrary time (e.g., 8:36). Since this plan uses a discrete time step (e.g., 15 minutes) as the basic time unit, the discharge emission time needs to be aligned to the nearest time step number. Specifically, this is usually determined by rounding down or using the nearest available time step. For example, with a 15-minute time step, time step number 1 corresponds to 8:00-8:15, number 2 corresponds to 8:15-8:30, and if the discharge emission time is 8:36, it will be aligned to number 3 (8:30-8:45). Here, the discharge emission time corresponds to the time step number on the absolute time axis.

[0088] It should be noted that the "current time step" in this scheme refers to the time step number being processed during the segmented flow velocity integration iteration process, which is a different concept from the "current moment" (i.e., now) in real-time scheduling.

[0089] S103-2: Repeat the iterative calculation until the cumulative propagation distance reaches or exceeds the total length of the river channel; wherein, the iterative calculation includes the following steps: using a preset weighting coefficient, perform a weighted average calculation on the upstream section natural flow value and the downstream section natural flow value at the current time step to obtain the characteristic flow at the current time step; wherein the downstream section natural flow value is obtained from the background flow sequence, and the upstream section natural flow value is obtained from the upstream hydrological forecast data; add the characteristic flow to the flow value corresponding to the discharge level to obtain the equivalent flow; use the equivalent flow to query the wave velocity-flow curve to obtain the instantaneous wave velocity at the current time step; multiply the instantaneous wave velocity by the time step length to obtain the propagation distance increment at the current time step, and accumulate it to the cumulative propagation distance; increment the current time step by one time step and proceed to the next time step.

[0090] The natural discharge value of an upstream section refers to the portion of the inflow from the upstream reservoir that is not affected by reservoir regulation. It is typically obtained through hydrological model forecasting based on measured data from upstream hydrological stations or rainfall forecasts from the upstream basin. Specifically, using a hydrological model of the upstream basin (such as the Xin'anjiang model), the gridded rainfall forecast is converted into the runoff generation process of the upstream section, and then the natural discharge value at each time step of the upstream section is obtained through river confluence calculations. The specific implementation method is the same as the principle for obtaining the background discharge sequence of the downstream section, and will not be elaborated here.

[0091] The downstream cross-section natural flow value is directly read from the background flow sequence, that is, the value of the "current time step" in the background flow sequence.

[0092] Since the natural flow values ​​at upstream and downstream sections of a river may differ (lower upstream and higher downstream, or vice versa), the flow at a single section cannot represent the flow field intensity of the entire river section. Therefore, a weighted average method is used to combine the upstream and downstream flow values ​​into a single characteristic flow value to approximate the average flow field intensity of the entire river channel. Thus, characteristic flow = preset weighting coefficient × upstream section natural flow value + (1 - preset weighting coefficient) × downstream section natural flow value.

[0093] It should be noted that the specific value of the preset weighting coefficient can be determined based on engineering practice experience, and this embodiment does not impose a specific limitation. For example, the preset weighting coefficient is usually set to 0.5, that is, the upstream and downstream traffic each account for half.

[0094] The flow rate value corresponding to the discharge level is the discharge flow rate value set in the discharge plan.

[0095] The equivalent flow rate is equal to the sum of the characteristic flow rate and the flow rate corresponding to the discharge level, representing the total flow rate after adding the discharge rate to the background flow field of the current river section.

[0096] It should be noted that when calculating the propagation distance increment, the time step must be converted to a time unit consistent with the instantaneous wave velocity unit (e.g., seconds) to ensure dimensional consistency. Those skilled in the art can perform the corresponding conversion based on the actual wave velocity unit (e.g., meters per second) and time step unit (e.g., seconds or minutes), which will not be elaborated here.

[0097] S103-3: If the cumulative propagation distance reaches or exceeds the total length of the river channel, the current time step shall be taken as the actual arrival time of the flood wave head.

[0098] Since if the cumulative propagation distance reaches or exceeds the total length of the river channel, it indicates that the flood wave front has reached the downstream section within this time step. Therefore, the current time step (i.e., the time step after completing the accumulation of propagation distance increments) should be used as the actual arrival time, rather than determining this after entering the next time step. Thus, the step of determining whether the cumulative propagation distance has reached or exceeded the total length of the river channel should occur before entering the next time step. After completing the accumulation of propagation distance increments, the termination condition should be checked immediately; if satisfied, the loop should exit.

[0099] Since there may be model errors or extreme situations that prevent the loop from terminating, this solution also has a fallback mechanism: a maximum number of propagation steps is preset (for example, set to 1.5 times the extracted baseline propagation time). If the number of propagation steps exceeds the maximum number of propagation steps and the accumulated propagation distance has not yet reached the full length of the river channel, the loop is forcibly terminated, and the actual arrival time is the time of discharge plus the baseline propagation time.

[0100] The time step count refers to the number of iterations that have been performed from the moment the leakage was emitted until the current moment.

[0101] It is understandable that each discharge level corresponds to only one reference propagation time in the discharge response sequence set.

[0102] S104: Determine the duration scaling ratio based on the actual arrival time and the reference propagation time; use the duration scaling ratio to scale the unit response sequence on the time axis and compensate for the amplitude to generate a corrected response sequence.

[0103] As a preferred implementation, the time step number corresponding to the actual arrival time is subtracted from the time step number corresponding to the discharge time to obtain the number of time steps between the two, which is taken as the actual propagation time; the extracted reference propagation time is divided by the actual propagation time to obtain the duration scaling ratio of the discharge scheme.

[0104] The actual arrival time is the time step number of the flood wave front reaching the downstream section, calculated iteratively.

[0105] It should be noted that the flood wave needs to travel a certain distance along the river channel to propagate from the reservoir to the downstream control section. Even with extremely high flow velocity, the propagation time will inevitably be a positive number. Therefore, there is at least a time step difference between the moment the discharge is initiated and the actual arrival time, and the actual propagation time is always greater than zero.

[0106] Since the reference propagation time is the number of propagation time steps obtained offline under low-water baseflow conditions and discharged at a certain flow rate, it represents the propagation speed under the slowest condition, while the actual propagation time reflects the true propagation speed under the current flow field intensity. Therefore, the time scaling ratio reflects how fast the actual wave velocity under the current flow field intensity is relative to the reference wave velocity under low-water baseflow conditions. If the time scaling ratio of a certain spillway scheme is greater than 1, it means that when the spillway is discharged at the spillway level of that scheme, the actual propagation time of the flood wave is less than the reference propagation time. That is, the wave velocity under the current flow field intensity is faster than during the dry season, and the flood wave arrives downstream earlier than expected. The subsequent waveform needs to be compressed on the time axis, and the amplitude needs to be increased accordingly to ensure water conservation. If the time scaling ratio of a certain spillway scheme is less than 1, it means that when the spillway is discharged at the spillway level of that scheme, the actual propagation time of the flood wave is greater than the reference propagation time. That is, the wave velocity under the current flow field intensity is slower than during the dry season, and the flood wave arrives downstream later than expected. The subsequent waveform needs to be stretched on the time axis, and the amplitude needs to be reduced accordingly. If the time scaling ratio of a certain spillway scheme is equal to 1, it means that the actual propagation time is equal to the reference propagation time. In this case, the unit response sequence does not need to be adjusted and can be directly used as the corrected response sequence.

[0107] It's important to understand that during flood wave propagation, changes in wave velocity not only affect arrival time but also cause compression or stretching of the waveform along the time axis (i.e., faster wave velocity results in a narrower waveform with a higher peak value, while slower wave velocity leads to a wider waveform with a lower peak value). Furthermore, since the volume of water released from a reservoir is a fixed physical quantity and does not increase or decrease due to the speed of propagation in the river channel, changes in wave velocity only alter the time distribution of the flood wave's arrival downstream, not the total volume of water released. Therefore, when scaling the waveform along the time axis, the flow amplitude must be compensated simultaneously to ensure that the total discharge represented by the unit response sequence before correction and the corrected response sequence remain consistent.

[0108] In this embodiment, the time axis length of the unit response sequence is divided by the duration scaling ratio to obtain the time axis length after scaling; the flow increment of each time step in the unit response sequence is multiplied by the duration scaling ratio to obtain the flow increment after amplitude compensation; wherein, the time axis scaling and amplitude compensation are performed simultaneously; the sequence after scaling and compensation is used with the actual arrival time as the starting point of the time axis to obtain the corrected response sequence; wherein the corrected response sequence starts from the time step corresponding to the actual arrival time, and each time step corresponds to a flow increment after amplitude compensation.

[0109] Since the corrected response sequence needs to be superimposed on the background flow sequence on the absolute time axis to assess whether the downstream total flow exceeds the safety threshold, the scaled and compensated sequence must be aligned to the absolute time axis. The actual arrival time is the absolute time when the flood wavefront reaches the downstream section. Placing the corrected response sequence from this point ensures that the amplitude-compensated flow increment in the corrected response sequence is correctly added to the natural flow value at the corresponding time step in the background flow sequence.

[0110] It can be understood that the time steps of the corrected response sequence are equal to the time steps of the unit response sequence divided by the duration scaling ratio, where the result of the division is rounded down or determined according to the actual mapping.

[0111] For example, assuming a time step of 15 minutes, the discharge time is the 10th time step, the actual arrival time is calculated to be the 27th time step, and the original unit response sequence has 24 time steps with a duration scaling ratio of 1.5, then the corrected response sequence has 24 ÷ 1.5 = 16 time steps. The corrected response sequence is then placed starting from the 27th time step: the first value in the sequence corresponds to the 27th time step, the second value to the 28th time step, and so on, up to the 16th value to the 42nd time step. These time steps are all located on the absolute time axis and are added one-to-one with the natural flow values ​​at the same time step in the background flow sequence.

[0112] S105: Superimpose the corrected response sequence onto the background flow sequence to obtain the downstream total flow sequence, and calculate the cumulative volume of flow exceeding the safety threshold at each time point in the sequence as the risk value; among the discharge schemes with a risk value of zero, select the scheme with the largest total flood discharge as the optimal discharge trajectory, and output the gate control signal.

[0113] The risk value determination process includes the following steps: 1) Starting from the time step corresponding to the actual arrival time, the corrected response sequence is aligned with the background flow sequence by time step and then added step by step to obtain the downstream total flow value at the same time step; where the time step not covered by the corrected response sequence is directly taken as the value of the corresponding time step of the background flow sequence as the downstream total flow value.

[0114] It is understandable that if only the baseline flow sequence has a value at a certain time step and the corrected response sequence has no corresponding value, the value of the baseline flow sequence is used as the total flow at that time step.

[0115] The downstream total flow value refers to the sum of the natural inflow (derived from the background flow sequence) and the flow increment generated by reservoir discharge (derived from the corrected response sequence) at the downstream control section within the same time step, that is, the total flow actually passing through the downstream section at that time step.

[0116] 2) Arrange the downstream total flow values ​​at each time step in the order of time steps to obtain the downstream total flow sequence.

[0117] 3) Compare the downstream total flow value at each time step in the downstream total flow sequence with the preset safety threshold. If the downstream total flow value is greater than the preset safety threshold, calculate the difference between the downstream total flow value and the preset safety threshold as the excess flow value. Multiply the excess flow value by the time step to obtain the excess volume at the corresponding time step.

[0118] It should be noted that the preset safety threshold is usually the maximum safe flow allowed to pass through the downstream river channel. Its specific value is determined based on the actual conditions of the downstream river channel, and this embodiment does not impose a specific limitation. For example, the safe discharge capacity of a certain river channel is 5000... / s.

[0119] Excess volume refers to the cumulative volume of water exceeding the safe threshold in the downstream total flow within a certain time step. It quantifies the excess water volume exceeding the safe discharge capacity of the river channel within that time step. A larger excess volume in a given time step indicates a greater amount of water exceeding the safe threshold, resulting in greater flood control pressure on the downstream river channel and a closer approach to or exceeding the levee's bearing capacity. Conversely, a smaller excess volume in a given time step indicates a less severe exceedance of the safe threshold and a lower risk.

[0120] 4) If the total downstream flow is less than or equal to the preset safety threshold, the excess volume at the corresponding time step will be set to zero.

[0121] 5) Accumulate the excess volume of all time steps to obtain the risk value of the leakage scheme.

[0122] The risk value is measured in cubic meters and represents the excess flood volume that the downstream river channel needs to handle. If the risk value of a certain spillway plan is zero, it means that the spillway plan will not cause downstream exceedances and is a safe plan; if the risk value of a certain spillway plan is greater than zero, it means that it will cause varying degrees of exceedances, with higher values ​​indicating higher risks.

[0123] As one possible implementation, for each spillway scheme, its risk value has been pre-calculated; spillway schemes with a risk value of zero are selected as candidate spillway schemes; for each candidate spillway scheme, the flow rate value corresponding to the spillway level at each time step is multiplied by the time step length to obtain the flood discharge volume at each time step, and then the flood discharge volumes of all time steps are summed to obtain the total flood discharge volume of the candidate spillway scheme; among all candidate spillway schemes, the total flood discharge volume of each candidate spillway scheme is compared, and the scheme with the largest total flood discharge volume is selected as the optimal spillway trajectory; if there are multiple candidate spillway schemes with the same total flood discharge volume and all of them are the largest, then one of them is selected.

[0124] Since the optimal discharge trajectory is the best selected from all candidate discharge schemes, it includes the discharge levels at each time step within the forecast period. Specifically, during actual execution, the system monitors the current time in real time. If the current time reaches the discharge launch time in the optimal discharge trajectory, the system, based on the discharge level in the optimal discharge trajectory and the current reservoir water level, queries the reservoir's water level-discharge capacity relationship curve to determine the gate opening required to reach the discharge level, generates a gate control signal, and sends it to the local control unit for execution. If the current time has not yet reached the discharge launch time, the gate remains in its current state (e.g., closed or maintaining a small flow discharge). If the current time has exceeded the discharge launch time, execution continues according to the discharge level in the optimal discharge trajectory until the scheduling cycle ends or a new gate control signal is received.

[0125] In actual operation, the system does not execute the optimal discharge trajectory only once. Instead, it typically updates the optimal discharge trajectory at fixed time intervals (e.g., 15 minutes or 1 hour), where each time interval can be called a scheduling cycle. At the beginning of each scheduling cycle, the system re-executes this method based on the latest weather forecasts and hydrological data to generate a new optimal discharge plan.

[0126] A flood control scheduling system for a water conservancy hub based on digital twins includes a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of a flood control scheduling method for a water conservancy hub based on digital twins.

[0127] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0128] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A flood control scheduling method for a water conservancy hub based on digital twins, characterized in that, The method includes: Obtain the pre-built set of discharge response sequences and wave velocity-discharge curves; the set of discharge response sequences includes the unit response sequence and reference propagation time corresponding to each flow level. The unit response sequence consists of flow increments arranged in relative time order, and the reference propagation time is the time from the discharge to the start of flow increase downstream; the wave velocity-discharge curve represents the functional relationship between the flow rate and wave velocity at the river cross-section. Obtain the background flow sequence of the downstream river channel, which consists of natural flow values ​​at each time point arranged in chronological order; For a discharge scheme that includes the discharge start time and discharge level, the corresponding unit response sequence and reference propagation time are extracted based on the discharge level; the actual arrival time is determined by segmented velocity integration using the wave velocity-flow curve; The duration scaling ratio is determined based on the actual arrival time and the reference propagation time; the duration scaling ratio is used to scale the unit response sequence on the time axis and compensate for the amplitude to generate a corrected response sequence. The corrected response sequence is superimposed on the background flow sequence to obtain the downstream total flow sequence. The cumulative volume of flow exceeding the safety threshold at each time point in the sequence is counted as the risk value. Among the discharge schemes with a risk value of zero, the scheme with the largest total discharge volume is selected as the optimal discharge trajectory, and the gate control signal is output.

2. The flood control scheduling method for a water conservancy hub based on digital twins according to claim 1, characterized in that, The set of leakage response sequences adopts a unified time step, and the unit response sequence corresponding to each flow level consists of flow increments arranged in time step order; where k represents the number of time steps elapsed since the leakage was issued, and k is an integer greater than or equal to 0. The k-th value in the unit response sequence represents the flow increment generated downstream at the k-th time step after the leakage was issued; the reference propagation time is the number of time steps elapsed from the issuance of the leakage to the start of flow increase downstream.

3. The flood control scheduling method for a water conservancy hub based on digital twins according to claim 2, characterized in that, The pre-construction process of the discharge response sequence set includes: Based on the reservoir water level-discharge capacity relationship curve, the minimum and maximum discharge capacities of the reservoir are determined, and the discharge capacity range is statistically obtained. The discharge capacity range is then discretized into multiple flow levels according to a preset flow step size. The low-water base flow value is determined based on historical hydrological data of the downstream river channel. A one-dimensional hydrodynamic model was constructed based on measured cross-sectional topographic data of the downstream river channel, and the parameters of the one-dimensional hydrodynamic model were calibrated using typical flood data. The boundary conditions of the one-dimensional hydrodynamic model were set to the low-water baseflow value, and the model was run until it reached a steady state across the entire river section. For each flow rate, a rectangular flow pulse with an amplitude equal to that flow rate and lasting for one time step was applied to the upstream boundary. Starting from the pulse emission moment, the downstream cross-sectional flow value is recorded step by step according to a unified time step. The low-water base flow value is subtracted from the downstream cross-sectional flow value at each time step to obtain the flow increment at the corresponding time step. The flow increments of all time steps are arranged in chronological order to form the unit response sequence for this flow level. Starting from the pulse emission moment, the flow increment of the downstream cross-section is checked step by step. The moment when the flow increment first exceeds zero is recorded as the rise time. The number of time steps between the rise time and the pulse emission moment is counted as the reference propagation time for this flow level. All flow rate levels are associated with and stored along with the baseline propagation time to form a flow discharge response sequence set.

4. A flood control scheduling method for a water conservancy hub based on digital twins according to claim 2, characterized in that, The wave velocity-flow rate curve is constructed offline through the following steps: In a one-dimensional hydrodynamic model, a series of steady-state background flows are set in a stepped increasing manner; wherein, the series of steady-state background flows covers the range of flows from the low-water flow value to the design flood flow value; and each steady-state background flow is used as the upstream boundary condition of the one-dimensional hydrodynamic model until the entire river section reaches a steady state; For each steady-state background flow, after the model reaches a steady state under the steady-state background flow, a small perturbation wave is applied to the upstream boundary based on the steady state; wherein the amplitude of the perturbation wave is a preset percentage of the steady-state background flow and lasts for one time step; The time when the peak of the disturbance wave passes through the upstream section is recorded as the upstream peak time, and the time when the disturbance wave passes through the downstream control section is recorded as the downstream peak time. The time step difference between the downstream peak time and the upstream peak time is calculated as the propagation time. The average wave velocity under steady-state background flow is obtained by dividing the total length of the river channel by the propagation time. The total length of the river channel is used to indicate the distance between the upstream section and the downstream control section. The steady-state background flow rate and the corresponding average wave velocity are paired, and the wave velocity-flow rate curve is obtained by power function regression fitting. Set a preset minimum wave velocity threshold for the wave velocity-flow curve; if the wave velocity obtained by querying the wave velocity-flow curve is less than the preset minimum wave velocity threshold, the preset minimum wave velocity threshold will be forcibly used as the query result.

5. A flood control scheduling method for a water conservancy hub based on digital twins according to claim 2, characterized in that, The process of obtaining the background flow sequence includes: Access the gridded rainfall forecast data released by the meteorological department to obtain the predicted rainfall values ​​for each grid unit in the forecast area at each future time step; Using a pre-built and calibrated interval hydrological model, the rainfall forecast values ​​of each grid cell are converted into runoff, and then combined according to the watershed outlet to obtain the runoff sequence of each time step in the downstream interval. The river confluence calculation method is used to calculate the flow sequence of each tributary along the river channel to the downstream control section, and obtain the natural flow value at each time step at the downstream control section. The natural flow values ​​at each time step are arranged in time step order to form a background flow sequence. The background flow sequence uses the same time steps as the discharge response sequence set. The values ​​in the background flow sequence are arranged in time step order, with i representing the time step number. i is a positive integer greater than or equal to 1. The i-th value in the background flow sequence represents the natural flow value of the downstream channel at the i-th time step.

6. A flood control scheduling method for a water conservancy hub based on digital twins according to claim 5, characterized in that, The process of obtaining the actual arrival time includes: Initialize the cumulative propagation distance to zero, and set the current time step to the time step number corresponding to the moment the leakage was emitted; Repeated iterative calculations are performed until the cumulative propagation distance reaches or exceeds the total length of the river channel. The iterative calculation includes the following steps: using preset weighting coefficients, the upstream and downstream natural flow values ​​at the current time step are weighted and averaged to obtain the characteristic flow at the current time step; the downstream natural flow value is obtained from the baseline flow sequence, and the upstream natural flow value is obtained from upstream hydrological forecast data; the characteristic flow is added to the flow value corresponding to the discharge level to obtain the equivalent flow; the wave velocity-flow curve is queried using the equivalent flow to obtain the instantaneous wave velocity at the current time step; the instantaneous wave velocity is multiplied by the time step length to obtain the propagation distance increment at the current time step, which is accumulated to the cumulative propagation distance; the current time step is incremented by one time step to proceed to the next time step. If the cumulative propagation distance reaches or exceeds the total length of the river channel, the current time step is taken as the actual arrival time of the flood wave head.

7. A flood control scheduling method for a water conservancy hub based on digital twins according to claim 6, characterized in that, The process of determining the duration scaling ratio includes: Subtract the time step number corresponding to the leakage emission time from the time step number corresponding to the actual arrival time to obtain the number of time steps between the two, which is the actual propagation time. Divide the retrieved baseline propagation time by the actual propagation time to obtain the duration scaling ratio of the leakage scheme.

8. A flood control scheduling method for a water conservancy hub based on digital twins according to claim 2, characterized in that, The step of scaling the unit response sequence on the time axis and compensating for amplitude using a time scaling ratio to generate a corrected response sequence includes: Divide the time axis length of the unit response sequence by the duration scaling ratio to obtain the time axis length after scaling. The traffic increment at each time step in the unit response sequence is multiplied by the duration scaling ratio to obtain the amplitude-compensated traffic increment; wherein, the time axis scaling and amplitude compensation are performed simultaneously. The scaled and compensated sequence is used as the starting point of the time axis to obtain the corrected response sequence; the corrected response sequence starts from the time step corresponding to the actual arrival time, and each time step corresponds to a flow increment after amplitude compensation.

9. A flood control scheduling method for a water conservancy hub based on digital twins according to claim 8, characterized in that, The risk value determination process includes: Starting from the time step corresponding to the actual arrival time, the corrected response sequence is aligned with the background flow sequence by time step and then added step by step to obtain the downstream total flow value at the same time step; where the time step not covered by the corrected response sequence is directly taken as the value of the corresponding time step of the background flow sequence as the downstream total flow value. Arrange the downstream total flow values ​​at each time step in the order of time steps to obtain the downstream total flow sequence; The downstream total flow value at each time step in the downstream total flow sequence is compared with a preset safety threshold. If the downstream total flow value is greater than the preset safety threshold, the difference between the downstream total flow value and the preset safety threshold is calculated as the excess flow value. The excess flow value is multiplied by the time step to obtain the excess volume at the corresponding time step. If the total downstream flow is less than or equal to the preset safety threshold, the excess volume at the corresponding time step will be set to zero. By summing up the excess volume of all time steps, the risk value of the leakage scheme is obtained.

10. A flood control scheduling system for a water conservancy hub based on digital twins, characterized in that, The system includes a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor executes the computer program to implement the steps of the method as described in any one of claims 1 to 9.

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