Ecological scheduling double-layer optimization model construction method for water-wind-light operation cascade reservoir

Abstract

The invention discloses a water-wind-light operation cascade reservoir ecological scheduling double-layer optimization model construction method. The model construction method comprises the following steps: collecting basic data and long-sequence hydrometeorological data of cascade hydropower stations, photovoltaic power and wind power in a target drainage basin; determining an ecological scheduling time period according to a main protection fish breeding period and a water temperature demand in the watershed; determining a water-wind-light combined operation scheduling target of each layer of the model, and determining an ecological scheduling target of each layer of the model; constructing a typical output scene based on the long-sequence wind and light data of the scheduling time period; fish breeding requirements, operation scheduling regulations of cascade hydropower stations, wind and light output uncertainty and power delivery channel limitation are comprehensively considered to delimit constraint conditions; a double-layer model nested structure is adopted to build a cascade reservoir ecological scheduling model under water-wind-light combined operation, and a scheduling scheme is solved and optimized layer by layer; and a cascade reservoir hour-scale refined scheduling scheme meeting fish breeding and new energy access requirements is formed.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of water conservancy and hydropower engineering, and particularly relates to a method for constructing a double-layer optimization model for ecological regulation of cascade reservoirs under water, wind and light operation. BACKGROUND

[0002] Ecological regulation is one of the important measures to alleviate the adverse effects of the operation of hydropower stations on the environment. The operation mode of hydropower stations is greatly changed compared with the traditional operation of single hydropower stations. The frequent peak shaving operation of hydropower stations to stabilize the output of new energy will inevitably change the outflow process of the power station, and may affect the ecological regulation test of the "artificial flood peak". Under the background of water, wind and light joint operation, how to use the regulation capacity of the counter-regulation reservoir to reduce the daily fluctuation of flow after the access of photovoltaic, while taking into account the ecological benefits of cascade hydropower stations and the power generation benefits of the water, wind and light joint operation system.

[0003] At present, the following problems exist in the ecological regulation of cascade hydropower stations under water, wind and light joint operation: (1) Lack of ecological regulation model for cascade hydropower stations under water, wind and light joint operation. At present, the research on water, wind and light joint operation mainly focuses on the daily peak regulation and dispatching of water, wind and light. How to consider the influence of photovoltaic access on ecological regulation and construct an ecological regulation model for cascade hydropower stations under water, wind and light joint operation is of great significance to guarantee the ecological and hydrological process requirements of fish reproduction period after the grid connection of new energy.

[0004] (2) Lack of fine dispatching scheme for cascade hydropower stations under the access of new energy such as photovoltaic and wind power. The existing ecological regulation scheme research focuses on daily hydrological process. How to consider the influence of intermittent output characteristics of photovoltaic on daily flow pulse process of cascade hydropower stations and research the daily fine dispatching scheme of cascade hydropower stations under water, wind and light joint operation to realize continuous rising of hourly scale has important reference value for improving new energy consumption rate and fully exerting ecological benefits of power stations. SUMMARY

[0005] In view of the above problems, the present application is proposed to provide a method for constructing a double-layer optimization model for ecological regulation of cascade reservoirs under water, wind and light operation to overcome the above problems or at least partially solve the above problems.

[0006] The present application provides a method for constructing a double-layer optimization model for ecological regulation of cascade reservoirs under water, wind and light operation, characterized in that the model construction method comprises: Collecting basic data of cascade hydropower stations, photovoltaic and wind power and long sequence hydro-meteorological data in the target basin; Determining the ecological regulation period according to the reproduction period of main protected fish species in the basin and water temperature demand; Determining the water, wind and light joint operation dispatching target of each layer of the model considering the power generation demand, and determining the ecological regulation target of each layer of the model considering the fish reproduction hydrological demand; Based on the long sequence of wind and light data of the scheduling period, the typical output scene is constructed considering the short-term output uncertainty of wind and light; The constraint conditions are drawn by comprehensively considering the fish breeding demand, the operation scheduling rules of cascade hydropower stations, the output uncertainty of wind and light, and the limitation of power export channel; The ecological scheduling model of cascade reservoirs under the joint operation of water, wind and light is built by adopting a double-layer model nesting structure, and the scheduling scheme is solved and optimized layer by layer; The output results of each layer model are arranged to form a fine scheduling scheme of cascade reservoirs at hourly scale which meets the demand of fish breeding and new energy access.

[0007] Further, the basic data of the target cascade hydropower station and the long sequence of hydrological and meteorological data are collected, specifically including: The water level-storage capacity relationship curve, output characteristic curve, unit installed capacity and historical operation scheduling data of the target cascade hydropower station are collected; The historical data of the daily output process of photovoltaic power stations and wind farms; The regional meteorological data of photovoltaic power stations and wind farms; The long sequence of daily runoff and daily water temperature process data in the region where the hydropower station dam site is located; The daily planned load characteristic curve of the target region.

[0008] Further, the ecological scheduling period is determined according to the breeding period and water temperature demand of the main protected fish in the basin, and the specific steps include: Firstly, the fish breeding months are determined based on literature research, and when the water temperature meets the breeding demand for 3 consecutive days based on the daily water temperature monitoring data, the ecological scheduling scheme is started to be solved.

[0009] Further, the double-layer optimization model building method of the ecological scheduling of cascade reservoirs under the operation of water, wind and light, characterized in that the water, wind and light joint operation scheduling target of each layer of the model is determined considering the power generation demand, and the ecological scheduling target of each layer of the model is determined considering the fish breeding hydrological demand, specifically including: The water, wind and light joint operation scheduling target of each layer of the model is determined considering the power generation demand, and the ecological scheduling target of each layer of the model is determined considering the fish breeding hydrological demand, specifically including: In the formula: is the hydropower output of the ith reservoir at the tth period, MW; is the time length of the tth period, h; T is the scheduling period, i.e. the main breeding period of fish, days; M is the number of cascade reservoirs, units; Considering the hydrological demands for fish reproduction, the ecological scheduling objectives for each layer of the model are determined. The ecological scheduling objectives for the upper-layer model are maximizing the number of consecutive days of high water levels and minimizing the difference between the daily increase in flow rate and the required daily increase. The function expression for maximizing the number of consecutive days of high water levels is: In the formula: T The effective consecutive number of days with rising water levels, where 'a' represents the number of days with rising water levels. m As the daily outflow increases, the variables are 0 and 1. m Record it as 1, otherwise record it as 0. d The minimum number of days of high water required for the target fish species to reproduce; The function expression for minimizing the difference between the daily increase in traffic and the required daily increase is: In the formula, The lowest level reservoir t Daily increase in outbound flow before and after the time period The daily increase in flow rate required for fish reproduction. The start time of the flood. The deadline for the flood to stop.

[0010] Furthermore, The methods for determining this include, but are not limited to, expert consultation, literature review, and data mining.

[0011] The ecological scheduling objective of the lower-level model is to minimize the fluctuation range of the outflow, and the function expression is: In the formula: The discharge flow rate at time t of the final stage reservoir is m. 3 / s; Let m be the average discharge flow over n time periods. 3 / s; n is the number of time periods. Here, the solution duration of the lower-level model is in days, and the step size is in hours, so n is 24; To represent the fluctuation range of the outflow, m 3 / s.

[0012] Furthermore, the construction of typical power output scenarios based on historical wind and solar data during the scheduling period, considering the uncertainty of wind and solar power output, specifically includes: Based on the collected hourly output data of photovoltaic power plants and wind farms, monthly models are built during the scheduling period; The probability density function of wind and solar power output per hour during the day is generated using the nonparametric kernel density estimation method. The Monte Carlo random sampling method was used to generate wind and solar power output scenarios. The generated landscape power output scene is reduced in size to obtain a typical scene; Scene reduction methods include reduction and K-means clustering.

[0013] Furthermore, the constraints, which comprehensively consider fish reproduction needs, the operation and scheduling procedures of cascade hydropower stations, the uncertainty of wind and solar power output, and limitations on power transmission channels, specifically include: Water balance constraints In the formula: , The first i The reservoir capacity of the hydropower station in the two periods before and after, m 3 ; , The first i The first hydroelectric power station t Inflow and outflow during the time period, m 3 / s; Water level constraints In the formula: , The first i The upper and lower limits of the water level of a hydropower station. The lower limit is generally the normal storage water level or the flood control limit water level, in meters. Downflow constraint In the formula: , The first i The upper and lower limits of the downstream discharge flow of the hydropower station in the river channel, m 3 / s; Output constraints In the formula: , The first i The upper and lower limits of the power output of the hydropower station. The lower limit is the guaranteed output, and the upper limit is the installed capacity, MW. Water level fluctuation constraints (daily fluctuation constraints in the upper-level model, hourly fluctuation constraints in the lower-level model) In the formula: For the first i The water level fluctuation limit for the hydropower station, in meters; Ecological constraints In the formula: is the daily average increase of the minimum flow of the water rising process required for fish reproduction, m 3 / s, and the determination method thereof includes but is not limited to expert consultation, literature research and data mining, etc. is the daily average flow difference of the water rising process in the dispatching period of the last stage power station, m 3 / s.

[0014] Further, the water, wind and light combined operation under the cascade reservoir ecological dispatching model is built by adopting a double-layer model nesting structure, and the dispatching scheme is solved and optimized layer by layer, and specifically includes: The upper layer model takes the maximum water, wind and light combined power generation, the maximum number of effective continuous water rising days and the difference between the daily flow increase and the required daily increase as the target, takes day as the solving step length, solves the daily scale cascade reservoir optimization dispatching scheme set, and outputs the water level change range and daily average flow of each day in the dispatching period; The ecological dispatching scheme with the maximum number of effective water rising days and the minimum difference between the daily flow increase and the required daily increase is screened out from the daily scale cascade reservoir optimization dispatching scheme set in time periods, and the time period to which the ecological dispatching scheme belongs is the ecological dispatching period; The lower layer model takes the minimum remaining load fluctuation and the minimum discharge flow fluctuation range in a day as the target, takes hour as the solving step length, optimizes the daily flow discharge process hour by hour, and solves and generates the hour scale cascade reservoir optimization dispatching scheme set; The sorting model of TOPSIS, COPRAS and MOORA is fused to build an integrated decision-making method based on multi-level subspace domination; The ecological dispatching scheme is automatically screened from the hour scale cascade reservoir optimization dispatching scheme set by applying the integrated decision-making method based on multi-level subspace domination.

[0015] Further, the output results of each layer model are arranged to form the cascade reservoir hour scale fine dispatching scheme meeting the fish reproduction and new energy access requirements, and the specific steps are as follows: In the ecological dispatching period, the hour scale ecological dispatching scheme is solved and automatically screened day by day; The daily scale dispatching scheme and the hour scale dispatching scheme are arranged, and in different time periods of the reproduction period, 2-3 cascade reservoir hour scale fine dispatching schemes meeting the fish reproduction and new energy access requirements are formed.

[0016] The above description is only a summary of the technical scheme of the present application, in order to more clearly understand the technical means of the present application, the content of the specification can be implemented, and in order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described as follows. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0018] Figure 1 A flowchart of a method for constructing a double-layer optimization model of ecological regulation of a cascade reservoir according to the present application; Figure 2 A flowchart of a method for constructing a double-layer optimization model of ecological regulation of a cascade reservoir according to the present application; Figure 3a and Figure 3b A typical wind and light output scene provided by the embodiment of the present application; Figure 4 A schematic diagram of discharge under a daily scale ecological regulation scheme of a cascade hydropower station provided by the embodiment of the present application; Figure 5 A schematic diagram of discharge under a daily scale ecological regulation scheme of a cascade hydropower station provided by the embodiment of the present application; DETAILED DESCRIPTION

[0019] Exemplary embodiments of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the drawings, it is understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0020] The terms "include" and "have" and any variations thereof in the specification and claims of the present application and the drawings are intended to cover non-exclusive inclusion, for example, inclusion of a series of steps or units.

[0021] The technical solutions of the present application will be described in further detail below in combination with the drawings and embodiments.

[0022] A method for constructing a double-layer optimization model of ecological regulation of a cascade reservoir to meet the needs of fish reproduction and new energy access, the specific steps are as follows: Collect the water level-storage capacity relationship curve, output characteristic curve, unit capacity of the target cascade hydropower station and historical operation and regulation data (historical inflow, outflow and water level process), installed capacity of photovoltaic and wind power stations and long sequence meteorological data in the region, and daily planned load characteristic curve of the target region.

[0023] The main target fish species for ecological regulation in the basin are drifting egg-laying fish, represented by the four major Chinese carp. The main breeding season for these fish is from May to June, and they begin spawning when the water temperature reaches above 18℃. Considering power generation demand, the scheduling objectives for the joint operation of hydropower, wind power, and solar power at each level of the model are determined. The scheduling objective of the upper-level model is to maximize the total power generation of the cascade reservoirs, expressed as: In the formula: Let be the hydropower output of the i-th reservoir during time period t, in MW; t represents the duration of time period t, in hours; T represents the scheduling period, i.e., the main breeding season for fish, in days; M represents the number of cascade reservoirs, in units. The scheduling objective of the lower-level model is to minimize the fluctuation of the remaining load, expressed as: In the formula: f 3 For the residual load fluctuation variance of the power grid, MW 2 ; For the first t The remaining load after deducting the output of photovoltaic, wind power, and hydropower during the time period, in MW; Planned load for the day, in MW; For the first i The first reservoir t Hydropower output during a given time period, in MW; For the first t Solar power output per time period, MW For the first t Wind power output during a given time period, in MW.

[0024] Considering the hydrological demands for fish reproduction, the ecological scheduling objectives for each layer of the model are determined. The ecological scheduling objectives for the upper-layer model are maximizing the number of consecutive days of high water levels and minimizing the difference between the daily increase in flow rate and the required daily increase. The function expression for maximizing the number of consecutive days of high water levels is: In the formula: T The effective consecutive number of days with rising water levels, where 'a' represents the number of days with rising water levels. m As the daily outflow increases, the variables are 0 and 1. m Record it as 1, otherwise record it as 0. d The minimum number of days of high water required for the reproduction of the target fish species is d, which is greater than or equal to 3 in this embodiment, based on the results of literature review.

[0025] The function expression for minimizing the difference between the daily increase in traffic and the required daily increase is: In the formula, The lowest level reservoir t Daily increase in outbound flow before and after the time period The daily increase in flow rate required for fish reproduction. The start time of the flood. The deadline for the flood to stop.

[0026] The methods for determining this include expert consultation, literature review, and data mining.

[0027] The ecological scheduling objective of the lower-level model is to minimize the fluctuation range of the outflow, and the function expression is: In the formula: The discharge flow rate at time t of the final stage reservoir is m. 3 / s; Let m be the average discharge flow over n time periods. 3 / s; n is the number of time periods. Here, the solution duration of the lower-level model is in days, and the step size is in hours, so n is 24; To represent the fluctuation range of the outflow, m 3 / s.

[0028] Based on long-series meteorological data during scheduling periods, typical power output scenarios are constructed considering the short-term power output uncertainty of wind and solar power.

[0029] like Figure 3a and Figure 3b As shown, this is a typical power output scene of the landscape.

[0030] Taking into account the needs of fish reproduction, the operation and scheduling procedures of cascade hydropower stations, the uncertainty of wind and solar power output, and the limitations of power transmission channels, the constraints are defined. Water balance constraints In the formula: , The first i The reservoir capacity of the hydropower station in the two periods before and after, m 3 ; , The first i The first hydroelectric power station t Inflow and outflow during the time period, m 3 / s; Water level constraints In the formula: , The first i The upper and lower limits of the water level of a hydropower station. The lower limit is generally the normal storage water level or the flood control limit water level, in meters. Downflow constraint In the formula: , The first i The upper and lower limits of the downstream discharge flow of the hydropower station in the river channel, m 3 / s; Output constraints In the formula: , The first i The upper and lower limits of the power output of the hydropower station. The lower limit is the guaranteed output, and the upper limit is the installed capacity, MW. Water level fluctuation constraints (daily fluctuation constraints in the upper-level model, hourly fluctuation constraints in the lower-level model) In the formula: For the first i The water level fluctuation limit for the hydropower station, in meters; Ecological constraints In the formula: The average daily flow difference during the flood season at the final power station during the dispatch period, in m 3 / s; A nested two-layer model was used to build an ecological scheduling model for cascade reservoirs under the integrated operation of water, wind, and solar power. The scheduling scheme was solved and optimized layer by layer. The scheduling period and time step were determined. In this example, the scheduling period of the upper-layer model is from May 1 to June 30, a total of 61 days, with a time step of 1 day. The scheduling period of the lower-layer model is 1 day, with a time step of 1 hour. The main model parameters are shown in Table 1.

[0031] Table 1 Model Parameter Settings The operating model was used to obtain an ecological dispatching scheme for cascade hydropower stations under the combined operation of water, wind, and solar power, such as... Figure 4 and Figure 5 As shown.

[0032] Beneficial effects: This invention proposes a method for constructing a two-layer optimization model for the ecological scheduling of cascade reservoirs that meets the needs of fish reproduction and new energy access. This method can provide technical support for the formulation of ecological scheduling schemes for cascade hydropower stations under the combined operation of hydropower and solar power, and improve the comprehensive operational efficiency of cascade hydropower stations.

[0033] The above detailed description has disclosed, by way of example, illustrative implementations of the application. It should be understood that changes can be made to the embodiments described and equivalents can be substituted without departing from the true spirit and scope of the application. In the claims, means-plus-function clauses are used where functionally equivalent structures are recited. Although a structure that would be perform the same function is described, it should be understood that structures recited in the means-plus-function clauses are interchangeable. The claims are thus to be understood in include all equivalents that functionally equivalent structures.

Claims

1. A method for constructing a two-layer optimization model for ecological scheduling of cascade reservoirs in water-wind-solar operation, characterized in that, The model construction method includes: Collect basic data and long-term hydrological and meteorological data on cascade hydropower stations, photovoltaic power, and wind power in the target river basin; The timing of ecological scheduling should be determined based on the breeding season of fish species protected in the watershed and their water temperature requirements. The scheduling objectives for the joint operation of water, wind and solar power at each layer of the model are determined by considering power generation demand, and the ecological scheduling objectives at each layer of the model are determined by considering the hydrological demand for fish reproduction. Based on long-series wind and solar data during scheduling periods, typical power output scenarios are constructed considering the short-term uncertainty of wind and solar power output. Taking into account the needs of fish reproduction, the operation and scheduling procedures of cascade hydropower stations, the uncertainty of wind and solar power output, and the limitations of power transmission channels, the constraints are defined. A nested two-layer model was used to build an ecological scheduling model of cascade reservoirs under the integrated operation of water, wind and solar power, and the scheduling scheme was solved and optimized layer by layer. The output results of each model layer are sorted out to form a refined hourly scheduling scheme for cascade reservoirs that meets the needs of fish reproduction and new energy access.

2. The method for constructing a two-layer optimization model for ecological scheduling of cascade reservoirs in water-wind-solar operation according to claim 1, characterized in that, The collection of basic data and long-term hydrological and meteorological data on cascade hydropower stations, photovoltaic power, and wind power in the target river basin specifically includes: Collect water level-storage capacity relationship curves, power output characteristic curves, installed capacity of hydropower units, and historical operation and scheduling data of the target cascade hydropower stations; Historical data on the daily power output of photovoltaic power plants and wind farms; Meteorological data for the areas where photovoltaic power plants and wind farms are located; Long-term daily runoff and daily water temperature data for the area where the hydropower station dam site is located; Daily planned load characteristic curve of the target area.

3. The method for constructing a two-layer optimization model for ecological scheduling of cascade reservoirs in water-wind-solar operation according to claim 1, characterized in that, The determination of ecological scheduling periods based on the breeding season of fish species in the watershed and their water temperature requirements specifically includes: To determine the fish breeding month, based on daily water temperature monitoring data, when the water temperature meets the breeding requirements for 3 consecutive days, the ecological scheduling scheme is solved.

4. The method for constructing a two-layer optimization model for ecological scheduling of cascade reservoirs in water-wind-solar operation according to claim 1, characterized in that, The process of determining the joint operation and scheduling objectives of water, wind, and solar power at each layer of the model, considering power generation demand, and determining the ecological scheduling objectives at each layer of the model, considering the hydrological demands for fish reproduction, specifically includes: Considering power generation demand, the scheduling objectives for the joint operation of hydropower, wind power, and solar power at each level of the model are determined. The scheduling objective of the upper-level model is to maximize the total power generation of the cascade reservoirs, expressed as: In the formula: Let be the hydropower output of the i-th reservoir during time period t, in MW; t represents the duration of time period t, in hours; T represents the scheduling period, i.e., the main breeding season for fish, in days; M represents the number of cascade reservoirs, in units. The scheduling objective of the lower-level model is to minimize the fluctuation of the remaining load, expressed as: In the formula: f 3 For the residual load fluctuation variance of the power grid, MW 2 ; For the first t The remaining load after deducting the output of photovoltaic, wind power, and hydropower during the time period, in MW; Planned load for the day, in MW; For the first i The first reservoir t Hydropower output during a given time period, in MW; For the first t Solar power output per time period, MW For the first t Wind power output during the period, in MW; Considering the hydrological demands for fish reproduction, the ecological scheduling objectives for each layer of the model are determined. The ecological scheduling objectives for the upper-layer model are maximizing the number of consecutive days of high water levels and minimizing the difference between the daily increase in flow rate and the required daily increase. The function expression for maximizing the number of consecutive days of high water levels is: In the formula: T The effective consecutive number of days with rising water levels is represented by 'a', where 'a' indicates the number of days with rising water levels. m As the daily outflow increases, the variables are 0 and 1. m Record it as 1, otherwise record it as 0. d The minimum number of days of high water required for the target fish species to reproduce; The function expression for minimizing the difference between the daily increase in traffic and the required daily increase is: In the formula, The lowest level reservoir t Daily increase in outbound flow before and after the time period The daily increase in flow rate required for fish reproduction. The start time of the flood. The floodwaters will cease by the end of the flood season. The methods for determining this include expert consultation, literature review, and data mining; The ecological scheduling objective of the lower-level model is to minimize the fluctuation range of the outflow, and the function expression is: In the formula: The discharge flow rate at time t of the final stage reservoir is m. 3 / s; Let m be the average discharge flow over n time periods. 3 / s; n is the number of time periods. Here, the solution duration of the lower-level model is in days, and the step size is in hours, so n is 24; To represent the fluctuation range of the outflow, m 3 / s.

5. The method for constructing a two-layer optimization model for ecological scheduling of cascade reservoirs in water-wind-solar operation according to claim 1, characterized in that, The construction of typical power output scenarios based on historical wind and solar data during the scheduling period, taking into account the uncertainty of wind and solar power output, specifically includes: Based on the collected hourly output data of photovoltaic power plants and wind farms, monthly models are built during the scheduling period; The probability density function of wind and solar power output per day is generated using the nonparametric kernel density estimation method. The Monte Carlo random sampling method was used to generate wind and solar power output scenarios. The generated landscape power output scene is reduced in size to obtain a typical scene; Scene reduction methods include reduction and K-means clustering.

6. The method for constructing a two-layer optimization model for ecological scheduling of cascade reservoirs in water-wind-solar operation according to claim 1, characterized in that, The constraints, which comprehensively consider fish reproduction needs, the operation and scheduling procedures of cascade hydropower stations, the uncertainty of wind and solar power output, and limitations on power transmission channels, specifically include: Water balance constraints In the formula: , The first i The reservoir capacity of the hydropower station in the two periods before and after, m 3 ; , The first i The first hydroelectric power station t Inflow and outflow during the time period, m 3 / s; Water level constraints In the formula: , The first i The upper and lower limits of the water level of a hydropower station. The lower limit is generally the normal storage water level or the flood control limit water level, in meters. Downflow constraint In the formula: , The first i The upper and lower limits of the downstream discharge flow of the hydropower station in the river channel, m 3 / s; Output constraints In the formula: , The first i The upper and lower limits of the power output of the hydropower station. The lower limit is the guaranteed output, and the upper limit is the installed capacity, MW. Water level variation constraints: the upper-level model uses daily variation constraints, and the lower-level model uses hourly variation constraints. In the formula: For the first i The water level fluctuation limit for the hydropower station, in meters; Ecological constraints In the formula: The minimum daily average flow rate required for fish reproduction during the flood season, in m 3 / s; The average daily flow difference during the flood season at the final power station during the dispatch period, in m 3 / s.

7. The method for constructing a two-layer optimization model for ecological scheduling of cascade reservoirs in water-wind-solar operation according to claim 1, characterized in that, The aforementioned method employs a two-layer nested model structure to construct a cascade reservoir ecological scheduling model under the integrated operation of water, wind, and solar power. The scheduling scheme is solved and optimized layer by layer, specifically including: The upper-level model aims to maximize the combined power generation of hydropower, wind power, and solar power, maximize the number of effective consecutive days of rising water levels, and minimize the difference between the daily increase in flow rate and the required daily increase in flow rate. It uses days as the solution step size to solve for a set of daily-scale optimal scheduling schemes for cascade reservoirs. The output results include the daily range of water level changes and the average daily flow rate within the specified scheduling period. From the daily-scale cascade reservoir optimization scheduling schemes, 2-3 ecological scheduling schemes with the most effective flood days and the smallest difference between the daily flow increase and the required daily flow increase are selected in different time periods. The time period to which the ecological scheduling scheme belongs is the ecological scheduling period. The lower-level model, within the daily average water level range of the ecological scheduling scheme, aims to minimize the fluctuation of the daily residual load and the fluctuation of the downstream flow. It optimizes the daily flow release process hourly with an hourly solution step size, and generates a set of hourly-scale cascade reservoir optimal scheduling schemes. By integrating ranking models such as TOPSIS, COPRAS, and MOORA, an integrated decision-making method based on multi-level subspace dominance is constructed. The integrated decision-making method based on multi-level subspace dominance is applied to automatically select ecologically biased scheduling schemes from the set of hourly-scale cascade reservoir optimization scheduling schemes.

8. The method for constructing a two-layer optimization model for ecological scheduling of cascade reservoirs in water-wind-solar operation according to claim 1, characterized in that, The process involves organizing the output results of each model layer to form a refined hourly-scale scheduling scheme for cascade reservoirs that meets the needs of fish reproduction and new energy access. Specific steps include: During the ecological scheduling period, the scheduling schemes with an hourly bias towards ecology are solved and automatically selected on a daily basis. By compiling daily and hourly scheduling schemes, 2-3 refined hourly scheduling schemes for cascade reservoirs can be developed to meet the needs of fish reproduction and new energy access during different periods of the breeding season.

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