Small and medium-sized reservoir dispatching optimization simulation method and system based on hydrological and hydrodynamic coupling model

Abstract

The invention discloses a small and medium-sized reservoir scheduling optimization method based on a hydrological and hydrodynamic coupling model. The method comprises the steps of obtaining basic data of a reservoir basin and performing data processing; setting boundary conditions, and adopting an SCS runoff production model to carry out runoff production calculation on the reservoir basin grids; a model is built based on a two-dimensional N-S equation, and two-dimensional hydrodynamic calculation is achieved; according to actual data, different reservoir region calculation methods are adopted, and a reservoir basin hydrological and hydrodynamic coupling model is constructed; carrying out reservoir basin multi-water-source water resource configuration, and optimizing boundary inflow conditions and a water demand upper limit for a scheduling rule; and according to the coupling model, in combination with a target function, a constraint condition and a water demand upper limit of the reservoir, optimizing a scheduling rule, and obtaining an optimal scheduling parameter and scheduling scheme. The method has the advantages that a real-time and forecast-period optimal reservoir scheduling strategy can be given, and the problem that real-time or forecast optimal scheduling simulation is difficult due to the fact that hydrological data of drainage basins where small and medium-sized reservoirs are located are deficient is well solved.

Description

Technical Field

[0001] The present invention relates to the technical field of reservoir optimization and dispatching, and in particular to a method and system for optimizing and simulating the dispatching of small and medium-sized reservoirs based on a hydrological and hydrodynamic coupling model. Background Art

[0002] Reservoir operation plays an important role in water resources management, aiming to balance the water supply, flood control, irrigation and ecological needs of the reservoir and maximize its comprehensive benefits. In particular, small and medium-sized reservoirs play an indispensable role in ensuring regional water supply, flood control and disaster reduction, and supporting agricultural production and ecological protection. However, many basins where small reservoirs are located lack long-term measured data, and traditional operation methods that rely on conceptual hydrological models and empirical rules face challenges in their application in these areas. These methods usually rely on a large amount of historical data for parameter calibration, which is not effective for basins with scarce data.

[0003] Hydrodynamic models have gradually become an effective tool for reservoir operation in areas with scarce data, as they can accurately describe the changes in physical quantities such as water level, flow velocity and flow in the reservoir basin. However, the use of hydrodynamic models alone in practical applications still faces challenges such as complex model construction, large amount of calculations and difficulty in real-time application. For this reason, the coupling technology of hydrological models and hydrodynamic models has emerged. This coupling model can not only make full use of limited hydrological data, but also greatly improve the accuracy and real-time performance of operation simulation through precise calculation of hydrodynamics.

[0004] It is particularly noteworthy that the hydrological and hydrodynamic coupling model can achieve real-time simulation and forecasting of the basin based on grid rainfall data. With this capability, the model can quickly respond to sudden rainfall events and dynamically changing hydrological conditions, providing strong support for flood control safety. In practical applications, this means that the dispatching system can predict changes in water level and flow before the flood arrives, optimize the dispatching strategy, reduce flood risks, and effectively protect people's lives and property.

[0005] In addition, the application of the coupling model in water resource management has also greatly improved the dispatching efficiency of reservoirs. By combining real-time rainfall data, the system can reasonably allocate water resources while preventing floods, ensuring the stability of agricultural irrigation and urban water supply, thereby achieving sustainable management of water resources on the basis of flood prevention and disaster reduction.

[0006] In summary, the hydrological and hydrodynamic coupling model has shown significant advantages in ensuring flood control safety, optimizing water resources management, and flood prevention and disaster reduction. The development of an optimization scheduling simulation method and system based on this model will not only help improve the scheduling accuracy of small and medium-sized reservoirs, but also have important practical significance for ensuring the safe management of regional water resources and flood prevention and disaster reduction. Summary of the invention

[0007] The object of the present invention is to provide a method and system for optimizing the operation of small and medium-sized reservoirs based on a hydrological and hydrodynamic coupling model, thereby solving the aforementioned problems existing in the prior art.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] A method for optimizing the operation of small and medium-sized reservoirs based on a hydrological and hydrodynamic coupling model.

[0010] S1. Basic information acquisition and data processing:

[0011] Obtain basic data of the reservoir basin; divide the calculation grid based on the basic data of the reservoir basin, and distribute the rainfall data in the basic data and the Manning coefficient and CN2 value obtained by using the basic data to the calculation grid to generate rainfall grid, Manning coefficient grid and CN2 grid respectively, so as to realize data processing;

[0012] S2, SCN model coupled with two-dimensional hydrodynamic model:

[0013] Boundary conditions are set for the reservoir basin, and the SCS runoff model is used to calculate the runoff of the reservoir basin grid. When there is underwater terrain in the reservoir basin, a two-dimensional hydrodynamic model is constructed based on the simplified analysis of the three-dimensional NS equation to realize the two-dimensional hydrodynamic calculation. When the runoff of the reservoir basin grid is greater than the preset threshold, it is used as the source item of the two-dimensional hydrodynamic model. At the same time, combined with the zero-dimensional reservoir area calculation and discharge calculation, a reservoir basin hydrological and hydrodynamic coupling model is constructed to realize the coupled calculation of the reservoir basin hydrological and hydrodynamic model.

[0014] S3. Allocation of water resources from multiple water sources in reservoir basins:

[0015] Based on the water balance relationship in the reservoir basin, the water sources outside the river are allocated among different water users to optimize the boundary inflow conditions and water demand upper limit for the dispatching rules;

[0016] S4. Optimization of reservoir real-time and forecast dispatching rules:

[0017] According to the reservoir basin hydrological and hydrodynamic coupling model, combined with the reservoir's objective function, constraints and water demand upper limit, the NSGA-II algorithm is used to optimize the scheduling rules, and the hierarchical analysis method is used to obtain the optimal scheduling parameters and scheduling scheme.

[0018] Preferably, the boundary conditions for the reservoir basin are set as follows:

[0019] Set grid rainfall as the global boundary of the reservoir basin, and set the reservoir discharge structure as the downstream boundary of the reservoir basin; if there are other water inflow conditions in the reservoir basin, add boundary conditions based on actual conditions.

[0020] Preferably, the SCS runoff model is used for runoff calculation. Specifically, the SCS runoff model is established based on the water balance principle, and the runoff calculation formula is derived according to the principles and basic assumptions of the SCS runoff model.

[0021] The water balance principle is expressed as,

[0022] P=I a +F+R (1)

[0023] The basic assumptions include that the ratio of the surface runoff depth to the rainfall minus the initial loss is equal to the ratio of the actual infiltration volume to the maximum soil storage capacity, and the initial rainfall loss is proportional to the maximum soil storage capacity; the formula expression is,

[0024]

[0025] I a =λS (3)

[0026] The initial loss coefficient λ is set to 0.2. Combining (1), (2), and (3), the flow calculation formula is:

[0027]

[0028] Where P is the rainfall; I a is the initial loss; F is the actual infiltration; R is the runoff depth; S is the maximum soil retention capacity.

[0029] Preferably, the simplified analysis based on the three-dimensional NS equations to construct a two-dimensional hydrodynamic model is as follows:

[0030] Assuming that the water surface fluctuation is small compared to the water depth, the three-dimensional NS equation is integrated along the water depth direction to transform it into a two-dimensional problem, which can simplify the analysis and obtain a two-dimensional hydrodynamic model; the two-dimensional hydrodynamic model includes the continuity equation and the momentum equation.

[0031] The continuity equation is,

[0032]

[0033] H(x,y,t)=z(x,y)+h(x,y,t) (6)

[0034] Among them, variable t is time; x, y are the positions in the reference coordinate system plane; V is the velocity vector; q is the external contribution or flux term; H is the water level altitude; z is the riverbed elevation; h is the water level;

[0035] The momentum equation is,

[0036]

[0037] in, is the Hamiltonian operator; V is the velocity vector, V=(u,v) T For dry elements, the bottom friction term is dominant in the equation, and the limiting form V = 0; v t is the horizontal eddy viscosity; c f is the friction coefficient; f c is the Coriolis force factor; k is the unit vector perpendicular to the rotation plane; g is the gravitational acceleration.

[0038] Preferably, the zero-dimensional reservoir area calculation is specifically as follows: when there is no underwater topography in the reservoir basin, a zero-dimensional water conservation model is constructed, and the upstream two-dimensional hydrodynamic model is used as the flow boundary input;

[0039] At this time, for the reservoir area,

[0040]

[0041] Among them, V t , V t+1 is the water storage capacity of the reservoir at the beginning and end of period t; is the average inflow flow during period t; is the average outflow during period t; f(*) is the reservoir capacity curve; Δt is the time interval from period t to period t+1; Z t is the storage capacity of the reservoir during period t.

[0042] Preferably, the discharge calculation is specifically that the flow of the hydraulic structure is jointly determined by the hydrological conditions of the upstream and downstream and the opening and closing conditions of the weirs and gates, and the corresponding hydraulic formula is selected to perform the flow calculation according to the outflow situation;

[0043] When the gate is closed, the flow rate through the gate Q = 0;

[0044] When the gate is open, the flow through the gate is calculated according to the wide crest weir formula.

[0045] when When , it is free outflow, and the flow rate through the gate is calculated as follows:

[0046]

[0047] when When , it is submerged outflow, and the flow rate through the gate is calculated as follows:

[0048]

[0049] Where m is the free outflow coefficient; is the flooding outflow coefficient; B is the total width of the gate opening; Z u is the water level upstream of the gate; Z d H is the water level downstream of the gate; sis the water depth downstream of the sluice gate; g is the acceleration due to gravity.

[0050] Preferably, during the coupled calculation of the hydrological and hydrodynamic model, the hydrological and hydrodynamic coupling model uses a combination of finite difference and finite volume methods to discretize the two-dimensional hydrodynamic model; for the case where the conventional grid boundary and the dual grid boundary are orthogonal, the finite difference method is used for numerical discretization, and for the case where the non-dual grid boundaries are orthogonal, the finite volume method is used for numerical discretization.

[0051] Preferably, step S4 specifically includes the following contents:

[0052] S41, according to the reservoir dispatching rules, carry out simulation calculation of reservoir dispatching, adjust boundary conditions, re-execute step S2, obtain new downstream flow, and obtain the values ​​of each objective function;

[0053] S42, using the NSGA-II algorithm, optimizing and adjusting the scheduling parameters according to the values ​​of each objective function, and obtaining newly generated scheduling parameters;

[0054] S43, repeating steps S41 to S42 until a scheduling parameter set and a scheduling scheme set that meet preset conditions are obtained;

[0055] S44. Using the analytic hierarchy process, select the optimal scheduling parameters and scheduling scheme from the scheduling parameter set and the scheduling scheme set.

[0056] Preferably, step S1 specifically includes the following contents:

[0057] S11. Obtain basic information: obtain topographic data of the reservoir basin, real-time or forecast rainfall data, land use data, soil data, existing dispatching rules, and discharge structure parameters;

[0058] S12. Data processing: (a) Terrain data processing: The original terrain data is converted into terrain DEM after processing and correction; (b) Dividing the computational grid: Using the grid tool to divide the computational grid in combination with the terrain DEM and the river location; (c) Generating rainfall grid: Using the GIS tool to assign rainfall data to the computational grid; (d) Generating Manning coefficient grid: The Manning coefficient distribution is calculated based on the land use data, and the Manning coefficient is assigned to the computational grid through the GIS tool; (e) Generating CN2 grid: The CN2 distribution is calculated based on the land use data and soil data, and the CN2 value is assigned to the computational grid through the GIS tool.

[0059] The present invention also aims to provide a small and medium-sized reservoir dispatch optimization system based on a hydrological and hydrodynamic coupling model, which can implement the above-mentioned method. The system includes:

[0060] Basic data acquisition and data processing module: obtain basic data of reservoir basins; divide the calculation grid based on the basic data of reservoir basins, and distribute the rainfall data in the basic data and the Manning coefficient and CN2 value obtained by using the basic data to the calculation grid to generate rainfall grids, Manning coefficient grids and CN2 grids respectively to realize data processing;

[0061] SCN model and two-dimensional hydrodynamic model coupling module: set boundary conditions for the reservoir basin, and use the SCS flow generation model to calculate the flow generation of each grid in the reservoir basin; when there is underwater terrain in the reservoir basin, a two-dimensional hydrodynamic model is constructed based on the simplified analysis of the three-dimensional NS equation to realize two-dimensional hydrodynamic calculation; when the flow generation of the reservoir basin grid is greater than the preset threshold, it is used as the source item of the two-dimensional hydrodynamic model, and combined with the zero-dimensional reservoir area calculation and discharge calculation, a reservoir basin hydrological and hydrodynamic coupling model is constructed to realize the coupled calculation of the reservoir basin hydrological and hydrodynamic model;

[0062] Reservoir Basin Multi-source Water Resources Allocation Module: Based on the water balance relationship in the reservoir basin division, the water sources outside the river are allocated among different water users to optimize the boundary inflow conditions and water demand upper limit for the dispatching rules;

[0063] Reservoir real-time and forecast dispatching rule optimization module: According to the reservoir basin hydrological and hydrodynamic coupling model, combined with the reservoir's objective function, constraints and water demand upper limit, the NSGA-II algorithm is used to optimize the dispatching rules, and the hierarchical analysis method is combined to obtain the optimal dispatching parameters and dispatching scheme.

[0064] The beneficial effects of the present invention are as follows: 1. The present invention fully considers the problem of lack of hydrological data in the basin where the reservoir is located. Through the coupling of the SCS-CN method and the two-dimensional hydrodynamic model, only a small amount of input data such as rainfall grids and CN2 grids is required to construct a reservoir basin simulation and forecasting model, thereby realizing the optimization of reservoir real-time and forecast scheduling rules. 2. The present invention provides a new method and technical framework for reservoir scheduling and water resource allocation for reservoirs with insufficient data, which can support simulation forecasting and scheduling decisions for reservoirs with insufficient data, and ensure flood control safety and water resource safety in reservoir basins. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 is a flow chart of a method in an embodiment of the present invention;

[0066] Figure 2 It is a technical roadmap of the method in the embodiment of the present invention;

[0067] Figure 3 is a reservoir water supply scheduling diagram in an embodiment of the present invention;

[0068] Figure 4 It is a flow chart of the NSGA-II algorithm in an embodiment of the present invention. DETAILED DESCRIPTION

[0069] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation methods described herein are only used to explain the present invention and are not used to limit the present invention.

[0070] like Figure 1 and Figure 2 As shown, in this embodiment, a method for optimizing the operation of small and medium-sized reservoirs based on a hydrological and hydrodynamic coupling model is provided. This method couples the hydrological model, the hydrodynamic model and the reservoir optimization operation algorithm to provide the optimal operation strategy for the reservoir in the real-time and forecast period. This method can better overcome the difficulty of simulating the real-time or forecast optimization operation caused by the lack of hydrological data in the basin where the small and medium-sized reservoirs are located. The method mainly includes the following parts:

[0071] 1. Basic information acquisition and data processing

[0072] Obtain basic data of reservoir basins; divide calculation grids based on the basic data of reservoir basins, and distribute rainfall data in the basic data and the Manning coefficient and CN2 values ​​obtained using the basic data to the calculation grids to generate rainfall grids, Manning coefficient grids and CN2 grids respectively to achieve data processing. Specifically include the following:

[0073] 1.1. Obtain basic information: obtain topographic data of the reservoir basin, real-time or forecast rainfall data, land use data, soil data, existing scheduling rules, and discharge structure parameters.

[0074] 1.2 Data processing:

[0075] (a) Terrain data processing: The original terrain data is processed and modified to be converted into terrain DEM.

[0076] (b) Divide the computational grid: Combine the terrain DEM and river location data and use the grid tool to divide the computational grid.

[0077] (c) Generate rainfall grid: The rainfall data is assigned to the computational grid through GIS tools to generate rainfall grid.

[0078] (d) Generate Manning coefficient grid: The Manning coefficient distribution is calculated based on land use data, and the Manning coefficient is assigned to the calculation grid through GIS tools to generate the Manning coefficient grid.

[0079] (e) Generate CN2 grid: CN2 distribution is calculated based on land use data and soil data, and CN2 values ​​are assigned to the calculation grid through GIS tools to generate CN2 grid.

[0080] The data processing processes (a) to (e) above are all performed in the same projection coordinate system.

[0081] 2. Coupling of SCN model with 2D hydrodynamic model

[0082] Boundary conditions are set for the reservoir basin, and the SCS runoff model is used to calculate the runoff of the reservoir basin grid; when there is underwater terrain in the reservoir basin, a two-dimensional hydrodynamic model is constructed based on the simplified analysis of the three-dimensional NS equation to achieve two-dimensional hydrodynamic calculation; when the runoff of the reservoir basin grid is greater than the preset threshold, it is used as the source item of the two-dimensional hydrodynamic model, and combined with the zero-dimensional reservoir area calculation and discharge calculation, a reservoir basin hydrological and hydrodynamic coupling model is constructed to achieve coupled calculation of the reservoir basin hydrological and hydrodynamic model. Specifically, it includes the following contents:

[0083] 2.1. Boundary conditions: Set grid rainfall as the global boundary of the reservoir basin, and set the reservoir discharge structure as the downstream boundary of the reservoir basin; if there are other water inflow conditions in the reservoir basin, add boundary conditions according to the actual situation.

[0084] 2.2. Runoff calculation: The SCS runoff model is used for runoff calculation. The SCS runoff model has only one model parameter, namely the runoff curve number (CN), and its value is determined by the underlying surface conditions of the basin and the previous soil moisture level. The establishment of the SCS runoff model is based on the principle of water balance.

[0085] The water balance principle can be expressed as:

[0086] P=I a +F+R (1)

[0087] The SCS runoff model includes two basic assumptions: (1) the ratio of the surface runoff depth to the rainfall minus the initial loss is equal to the ratio of the actual infiltration volume to the maximum soil storage capacity; (2) the initial loss of rainfall is proportional to the maximum soil storage capacity, that is,

[0088]

[0089] I a =λS (3)

[0090] The initial loss coefficient λ is generally taken as 0.2. Combining (1), (2), and (3), the flow calculation formula is:

[0091]

[0092] Where P is the rainfall, mm; I ais the initial loss, mm; F ​​is the actual infiltration, mm; R is the runoff depth, mm; S is the maximum soil retention capacity, mm. The S value is related to soil type, land use pattern, and soil initial moisture level, and can be expressed by the dimensionless coefficient CN. The calculation formula is: The value of CN generally ranges from 30 to 100 and is determined empirically based on land use type and soil grouping.

[0093] 2.3. Two-dimensional hydrodynamic calculation: The derivation of the two-dimensional hydrodynamic model (two-dimensional shallow water equation) is based on the three-dimensional Navier-Stokes (NS) equation. Since it is relatively complicated to directly solve the three-dimensional NS equation, for shallow water problems, it can be assumed that the water surface fluctuation value is small compared to the water depth, and the NS equation is integrated along the water depth direction, thereby converting it into a two-dimensional problem and simplifying the analysis. The simplified equation is the two-dimensional shallow water equation, and its expression consists of two parts: the continuity equation and the momentum equation:

[0094] The continuity equation is,

[0095]

[0096] H(x,y,t)=z(x,y)+h(x,y,t) (6)

[0097] Among them, variable t is time; x, y are the positions in the reference coordinate system plane; V is the velocity vector; q is the external contribution or flux term (source / sink term); H is the water level altitude; z is the riverbed elevation; h is the water level;

[0098] The momentum equation is,

[0099]

[0100] in, is the Hamiltonian operator; V is the velocity vector, V=(u,v) T For dry elements, the bottom friction term is dominant in the equation, and the limiting form V = 0; v t is the horizontal eddy viscosity; c f is the friction coefficient; f c is the Coriolis force; k is the unit vector perpendicular to the rotation plane; g is the gravitational acceleration.

[0101] 2.4. Zero-dimensional reservoir area calculation: When the reservoir has underwater topography, the two-dimensional hydrodynamic model is directly constructed using the above steps. When the reservoir basin has no underwater topography, a zero-dimensional water conservation model needs to be constructed, and the upstream two-dimensional hydrodynamic model is used as the flow boundary input;

[0102] At this time, for the reservoir area,

[0103]

[0104] Among them, V t , V t+1 is the water storage capacity of the reservoir at the beginning and end of period t; is the average inflow during period t, obtained from the two-dimensional hydrodynamic model and rainfall flow module, in m 3 / s; is the average outbound flow rate during period t, in m 3 / s; f(*) is the reservoir capacity curve; Δt is the time interval from period t to period t+1; Z t is the storage capacity of the reservoir during period t.

[0105] 2.5. Discharge calculation: The flow pattern near hydraulic structures is very complex and difficult to simulate with a one-dimensional model. It can only be simplified. It is generally believed that the flow of hydraulic structures is determined by the hydrological conditions of the upstream and downstream and the opening and closing of the weirs. According to the outflow situation, the corresponding hydraulic formula is used for flow calculation.

[0106] When the gate is closed, the flow rate through the gate Q = 0;

[0107] When the gate is open, the flow through the gate is calculated according to the wide crest weir formula.

[0108] when When , it is free outflow, and the flow rate through the gate is calculated as follows:

[0109]

[0110] Among them, formula (7) can be linearized into the following formula:

[0111]

[0112] when When , it is submerged outflow, and the flow rate through the gate is calculated as follows:

[0113]

[0114] Where m is the free outflow coefficient, which is generally between 0.325 and 0.385; is the flooding outflow coefficient, which is generally less than 1; B is the total width of the gate opening; Z u is the water level upstream of the gate; Z d H is the water level downstream of the gate; s It is the water depth downstream of the sluice.

[0115] 2.6. Coupled calculation of hydrological and hydrodynamic models

[0116] A runoff threshold is set. When the runoff of the reservoir basin grid obtained in the runoff calculation is greater than the threshold, it is used as the source item in the two-dimensional hydrodynamic model, and combined with 2.4 zero-dimensional reservoir area calculation and 2.5 discharge calculation, the water level in front of the reservoir and the reservoir water storage capacity are calculated.

[0117] During the coupled calculation of the hydrological and hydrodynamic models, the hydrological and hydrodynamic coupling model uses a combination of finite difference and finite volume methods to discretize the two-dimensional hydrodynamic model; for the case where the conventional grid boundary and the dual grid boundary are orthogonal, that is, the local orthogonal case, the finite difference method is used for numerical discretization; in general, the local orthogonal condition is difficult to meet, so the finite volume method is used for numerical discretization.

[0118] III. Allocation of water resources from multiple water sources in reservoir basins

[0119] The basin water resources system mainly includes natural water from rivers, groundwater, recycled water, external water and other water sources, which supply multiple types of water users such as life, industry, agriculture and ecology. The multi-source water resource allocation in the reservoir basin starts from the water balance relationship in the reservoir basin division, and allocates groundwater, recycled water and other water sources outside the river among different water users, so as to optimize the boundary inflow conditions and water demand upper limit for the dispatching rules.

[0120] 4. Optimization of reservoir real-time and forecast dispatching rules

[0121] According to the reservoir basin hydrological and hydrodynamic coupling model, combined with the reservoir's objective function, constraints and water demand upper limit, the NSGA-II algorithm is used to optimize the scheduling rules, and the hierarchical analysis method is used to obtain the optimal scheduling parameters and scheduling scheme.

[0122] The decision variable is the reservoir operation diagram for the simulation period or forecast period, which is solved by the simulation-optimization method. The reservoir operation diagram divides the reservoir into different operation intervals through the operation limit line, such as Figure 3 As shown in the figure, it is a predefined form of the reservoir water supply scheduling diagram with three water supply tasks: ecological, domestic and agricultural. Its scheduling restriction line divides the reservoir capacity into four scheduling areas, namely A, B, C, and D, which are the water supply restriction area, ecological water supply guarantee area, domestic water supply guarantee area, and agricultural water supply guarantee area. When using the scheduling diagram, water supply decisions are made for water users based on the location of the initial water level of the reservoir simulation or forecast period in the water supply scheduling area. This part specifically includes the following contents,

[0123] 4.1. According to the reservoir operation rules, carry out simulation calculation of reservoir operation, adjust the parameters of the discharge structure, that is, adjust the boundary conditions in 2.1, and then re-execute step S2 to obtain a new discharge flow to obtain the values ​​of each objective function.

[0124] 4.2. Optimization unit: The optimization algorithm is the NSGA-II algorithm. According to the feedback of each objective function value, the scheduling parameters are optimized and adjusted to obtain the newly generated scheduling parameters.

[0125] 4.3. Repeat steps 4.1 to 4.2 until a satisfactory scheduling parameter set and scheduling solution set are obtained. Figure 4 As shown in the figure, NSGA-II includes three key operators: non-dominated sorting, crowding calculation, and elite retention. Among them, non-dominated sorting compares the dominance relationship between each individual and other individuals in the population, determines whether it dominates all other individuals, and calculates the Pareto solution set; crowding calculation calculates the sum of the distance difference between an individual and its two adjacent individuals in each sub-objective function. When individuals belong to Pareto solution sets of different levels, those with smaller level numbers are given priority. If individuals belong to the same level of Pareto solution sets, those with larger crowding distances are given priority. Elite retention keeps the excellent individuals in the parent generation directly into the offspring to prevent the loss of the Pareto optimal solution. Repeat non-dominated sorting and crowding calculation until a satisfactory set of scheduling parameters and scheduling solutions are obtained.

[0126] 4.4. Use the analytic hierarchy process (AHP) to select the optimal scheduling parameters and scheduling schemes from the scheduling parameter set and scheduling scheme set. The AHP goal is to select the optimal scheduling scheme. There are n candidate schemes and m evaluation criteria (average guarantee rate, abandoned water volume, and number of opening modification times, etc.). Construct a judgment matrix and solve the eigenvector to obtain the weight of each criterion. Score each scheme's performance under each criterion based on expert opinions. Finally, multiply the score of each scheme by its corresponding criterion weight and add up to get the total score of each scheme. The scheme with the highest score is the best choice.

[0127] In this embodiment, a small and medium-sized reservoir scheduling optimization system based on a hydrological and hydrodynamic coupling model is also provided. The system can implement the above-mentioned method, and the system includes:

[0128] (1) Basic data acquisition and data processing module: obtain the basic data of the reservoir basin; divide the calculation grid based on the basic data of the reservoir basin, and distribute the rainfall data in the basic data and the Manning coefficient and CN2 value obtained by using the basic data to the calculation grid to generate rainfall grid, Manning coefficient grid and CN2 grid respectively to realize data processing.

[0129] (2) SCN model and two-dimensional hydrodynamic model coupling module: set boundary conditions for the reservoir basin, and use the SCS flow generation model to calculate the flow generation of each grid in the reservoir basin; when there is underwater terrain in the reservoir basin, a two-dimensional hydrodynamic model is constructed based on the simplified analysis of the three-dimensional NS equation to realize two-dimensional hydrodynamic calculation; when the flow generation of the reservoir basin grid is greater than the preset threshold, it is used as the source item of the two-dimensional hydrodynamic model, and combined with the zero-dimensional reservoir area calculation and discharge calculation, a reservoir basin hydrological and hydrodynamic coupling model is constructed to realize the coupled calculation of the reservoir basin hydrological and hydrodynamic model.

[0130] (3) Reservoir basin multi-source water resource allocation module: Based on the water balance relationship in the reservoir basin division, the water sources outside the river are allocated among different water users to optimize the boundary inflow conditions and water demand upper limit for the scheduling rules.

[0131] (4) Reservoir real-time and forecast dispatching rule optimization module: Based on the reservoir basin hydrological and hydrodynamic coupling model, combined with the reservoir's objective function, constraints and water demand upper limit, the NSGA-II algorithm is used to optimize the dispatching rules, and the hierarchical analysis method is used to obtain the optimal dispatching parameters and dispatching scheme.

[0132] By adopting the above technical solution disclosed in the present invention, the following beneficial effects are obtained:

[0133] The present invention provides a method and system for optimizing the dispatching of small and medium-sized reservoirs based on a hydrological and hydrodynamic coupling model. The present invention fully considers the problem of lack of hydrological data in the basin where the reservoir is located. Through the coupling of the SCS-CN method and the two-dimensional hydrodynamic model, only a small amount of input data such as rainfall grids and CN2 grids is required to construct a reservoir basin simulation and forecasting model, and optimize the real-time and forecast dispatching rules of the reservoir. The present invention provides a new method and technical framework for the dispatching and water resource allocation of reservoirs with insufficient data, which can support the simulation forecasting and dispatching decision-making of reservoirs with insufficient data, and ensure the flood control safety and water resource safety of the reservoir basin.

[0134] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be considered as the scope of protection of the present invention.

Claims

1. A method for optimizing the operation of small and medium-sized reservoirs based on a hydrological and hydrodynamic coupling model, characterized in that: S1. Basic information acquisition and data processing: Obtain basic data of the reservoir basin; divide the calculation grid based on the basic data of the reservoir basin, and distribute the rainfall data in the basic data and the Manning coefficient and CN2 value obtained by using the basic data to the calculation grid to generate rainfall grid, Manning coefficient grid and CN2 grid respectively, so as to realize data processing; S2, SCN model coupled with two-dimensional hydrodynamic model: Boundary conditions are set for the reservoir basin, and the SCS runoff model is used to calculate the runoff of the reservoir basin grid. When there is underwater terrain in the reservoir basin, a two-dimensional hydrodynamic model is constructed based on the simplified analysis of the three-dimensional NS equation to realize the two-dimensional hydrodynamic calculation. When the runoff of the reservoir basin grid is greater than the preset threshold, it is used as the source item of the two-dimensional hydrodynamic model. At the same time, combined with the zero-dimensional reservoir area calculation and discharge calculation, a reservoir basin hydrological and hydrodynamic coupling model is constructed to realize the coupled calculation of the reservoir basin hydrological and hydrodynamic model. S3. Allocation of water resources from multiple water sources in reservoir basins: Based on the water balance relationship in the reservoir basin, the water sources outside the river are allocated among different water users to optimize the boundary inflow conditions and water demand upper limit for the dispatching rules; S4. Optimization of reservoir real-time and forecast dispatching rules: According to the reservoir basin hydrological and hydrodynamic coupling model, combined with the reservoir's objective function, constraints and water demand upper limit, the NSGA-II algorithm is used to optimize the scheduling rules, and the hierarchical analysis method is used to obtain the optimal scheduling parameters and scheduling scheme.

2. The method for optimizing the operation of small and medium-sized reservoirs based on the hydrological and hydrodynamic coupling model according to claim 1 is characterized in that: The boundary conditions for the reservoir basin are as follows: Set grid rainfall as the global boundary of the reservoir basin, and set the reservoir discharge structure as the downstream boundary of the reservoir basin; if there are other water inflow conditions in the reservoir basin, add boundary conditions based on actual conditions.

3. The method for optimizing the operation of small and medium-sized reservoirs based on the hydrological and hydrodynamic coupling model according to claim 1 is characterized in that: The SCS runoff model is used to calculate runoff. Specifically, the SCS runoff model is established based on the water balance principle, and the runoff calculation formula is derived according to the principles and basic assumptions of the SCS runoff model. The water balance principle is expressed as, P=I a +F+R (1) The basic assumptions include that the ratio of the surface runoff depth to the rainfall minus the initial loss is equal to the ratio of the actual infiltration volume to the maximum soil storage capacity, and the initial rainfall loss is proportional to the maximum soil storage capacity; the formula expression is, I a =λS (3) The initial loss coefficient λ is set to 0.

2. Combining (1), (2), and (3), the flow calculation formula is: Where P is the rainfall; I a is the initial loss; F is the actual infiltration; R is the runoff depth; S is the maximum soil retention capacity.

4. The method for optimizing the operation of small and medium-sized reservoirs based on the hydrological and hydrodynamic coupling model according to claim 1 is characterized in that: The two-dimensional hydrodynamic model is constructed based on the simplified analysis of the three-dimensional NS equations. Assuming that the water surface fluctuation is small compared to the water depth, the three-dimensional NS equation is integrated along the water depth direction to transform it into a two-dimensional problem, which can simplify the analysis and obtain a two-dimensional hydrodynamic model; the two-dimensional hydrodynamic model includes the continuity equation and the momentum equation. The continuity equation is, H(x,y,t)=z(x,y)+h(x,y,t) (6) Among them, variable t is time; x, y are the positions in the reference coordinate system plane; V is the velocity vector; q is the external contribution or flux term; H is the water level altitude; z is the riverbed elevation; h is the water level; The momentum equation is, in, is the Hamiltonian operator; V is the velocity vector, v = (u, v) T For dry elements, the bottom friction term is dominant in the equation, and the limiting form V = 0; v t is the horizontal eddy viscosity; c f is the friction coefficient; f c is the Coriolis force factor; k is the unit vector perpendicular to the rotation plane; g is the gravitational acceleration.

5. The method for optimizing the operation of small and medium-sized reservoirs based on the hydrological and hydrodynamic coupling model according to claim 4 is characterized in that: Specifically, the zero-dimensional reservoir area calculation is as follows: when there is no underwater topography in the reservoir basin, a zero-dimensional water conservation model is constructed, and the upstream two-dimensional hydrodynamic model is used as the flow boundary input; At this time, for the reservoir area, Among them, V t , V t+1 is the water storage capacity of the reservoir at the beginning and end of period t; is the average inflow flow during period t; is the average outflow during period t; f(*) is the reservoir capacity curve; Δt is the time interval from period t to period t+1; Z t is the storage capacity of the reservoir during period t.

6. The method for optimizing the operation of small and medium-sized reservoirs based on the hydrological and hydrodynamic coupling model according to claim 1 is characterized in that: Specifically, the discharge of hydraulic structures is determined by the hydrological conditions of the upstream and downstream and the opening and closing of weirs and gates. According to the outflow situation, the corresponding hydraulic formula is used to calculate the flow. When the gate is closed, the flow rate through the gate Q = 0; When the gate is open, the flow through the gate is calculated according to the wide crest weir formula. when When , it is free outflow, and the flow rate through the gate is calculated as follows: when When , it is submerged outflow, and the flow rate through the gate is calculated as follows: Where m is the free outflow coefficient; is the flooding outflow coefficient; B is the total width of the gate opening; Z u is the water level upstream of the gate; Z d H is the water level downstream of the gate; s is the water depth downstream of the sluice gate; g is the acceleration due to gravity.

7. The method for optimizing the operation of small and medium-sized reservoirs based on the hydrological and hydrodynamic coupling model according to claim 1 is characterized by: During the coupled calculation of the hydrological and hydrodynamic models, the hydrological and hydrodynamic coupling model uses a combination of finite difference and finite volume methods to discretize the two-dimensional hydrodynamic model; for the case where the conventional grid boundary and the dual grid boundary are orthogonal, the finite difference method is used for numerical discretization, and for the case where the non-dual grid boundaries are orthogonal, the finite volume method is used for numerical discretization.

8. The method for optimizing the operation of small and medium-sized reservoirs based on the hydrological and hydrodynamic coupling model according to claim 1 is characterized by: Step S4 specifically includes the following contents: S41, according to the reservoir dispatching rules, carry out simulation calculation of reservoir dispatching, adjust boundary conditions, re-execute step S2, obtain new downstream flow, and obtain the values ​​of each objective function; S42, using the NSGA-II algorithm, optimizing and adjusting the scheduling parameters according to the values ​​of each objective function, and obtaining newly generated scheduling parameters; S43, repeating steps S41 to S42 until a scheduling parameter set and a scheduling scheme set that meet preset conditions are obtained; S44. Using the analytic hierarchy process, select the optimal scheduling parameters and scheduling scheme from the scheduling parameter set and the scheduling scheme set.

9. The method for optimizing the operation of small and medium-sized reservoirs based on the hydrological and hydrodynamic coupling model according to claim 1 is characterized by: Step S1 specifically includes the following contents: S11. Obtain basic information: obtain topographic data of the reservoir basin, real-time or forecast rainfall data, land use data, soil data, existing dispatching rules, and discharge structure parameters; S12. Data processing: (a) Terrain data processing: converting the original terrain data into terrain DEM after processing and correction; (b) Divide the computational grid: Use the grid tool to divide the computational grid based on the terrain DEM and river location; (c) Generate the rainfall grid: Use the GIS tool to assign the rainfall data to the computational grid; (d) Generate the Manning coefficient grid: Calculate the Manning coefficient distribution based on the land use data, and assign the Manning coefficient to the computational grid through the GIS tool; (e) Generate the CN2 grid: Calculate the CN2 distribution based on the land use data and soil data, and assign the CN2 value to the computational grid through the GIS tool.

10. A small and medium-sized reservoir dispatch optimization system based on a hydrological and hydrodynamic coupling model, characterized by: The system can implement the method described in any one of claims 1 to 9, and the system includes: Basic data acquisition and data processing module: obtain basic data of reservoir basins; divide the calculation grid based on the basic data of reservoir basins, and distribute the rainfall data in the basic data and the Manning coefficient and CN2 value obtained by using the basic data to the calculation grid to generate rainfall grids, Manning coefficient grids and CN2 grids respectively to realize data processing; SCN model and two-dimensional hydrodynamic model coupling module: set boundary conditions for the reservoir basin, and use the SCS flow generation model to calculate the flow generation of each grid in the reservoir basin; when there is underwater terrain in the reservoir basin, a two-dimensional hydrodynamic model is constructed based on the simplified analysis of the three-dimensional NS equation to realize two-dimensional hydrodynamic calculation; when the flow generation of the reservoir basin grid is greater than the preset threshold, it is used as the source item of the two-dimensional hydrodynamic model, and combined with the zero-dimensional reservoir area calculation and discharge calculation, a reservoir basin hydrological and hydrodynamic coupling model is constructed to realize the coupled calculation of the reservoir basin hydrological and hydrodynamic model; Reservoir Basin Multi-source Water Resources Allocation Module: Based on the water balance relationship in the reservoir basin division, the water sources outside the river are allocated among different water users to optimize the boundary inflow conditions and water demand upper limit for the dispatching rules; Reservoir real-time and forecast dispatching rule optimization module: According to the reservoir basin hydrological and hydrodynamic coupling model, combined with the reservoir's objective function, constraints and water demand upper limit, the NSGA-II algorithm is used to optimize the dispatching rules, and the hierarchical analysis method is combined to obtain the optimal dispatching parameters and dispatching scheme.

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