Cascade hydropower modeling method, system, equipment and medium

Abstract

The invention discloses a cascade hydropower modeling method, system and device and a medium, and the method comprises the steps: obtaining hydropower data of a hydropower plant, and carrying out the preprocessing of the hydropower data, and obtaining first hydropower data; constructing a day-ahead market clearing optimization model according to the first hydropower data, and performing first optimization on each unit of the day-ahead market clearing optimization model to obtain a first optimization result; based on the first optimization result, performing second optimization on the output plan of each unit in the day-ahead market clearing optimization model to obtain a second optimization result; the node electricity price is calculated according to the second optimization result, the first optimization result, the second optimization result and the node electricity price are sorted, a cascade hydropower optimization result is obtained, cascade hydropower modeling is achieved, and a more reliable decision basis is provided for hydropower optimization.

Description

Technical Field

[0001] This invention relates to the field of cascade hydropower clearing modeling technology, and in particular to a cascade hydropower modeling method, system, equipment and medium. Background Technology

[0002] In the current modeling of cascade hydropower clearing, if the reservoir water level is high and the inflow, which typically includes both upstream reservoir flow and natural inflow, exceeds the power generation capacity of the hydropower units, the reservoir may experience water wastage. To ensure reservoir water level balance, the modeling incorporates water level control constraints for cascade hydropower, including reservoir parameters such as water consumption rate and water surface area. The water level at a given moment is related to the inflow and outflow at that moment, and the model requires that the water level at each moment be between the highest and lowest levels. A penalty term related to the wasted water flow is added to the model's objective function to ensure that the wasted water flow is minimized.

[0003] Existing water level control constraints can lead to the following problems: although a penalty for water wastage is set, the scenarios in which this wastage occurs are not restricted. When other penalty terms in the objective function take effect, it may result in unreasonable water wastage, such as in cross-sectional blockage scenarios where cross-sectional constraints are prioritized to ensure system operational safety. Generally, the cost of water wastage penalty is orders of magnitude smaller than that of cross-sectional constraint relaxation penalty. Hydropower plants generate water wastage to increase the power generation flow of downstream power plants, but this wastage occurred before the actual water level reached its upper limit, which is inconsistent with the actual operating patterns of hydropower plants.

[0004] Therefore, in the existing modeling methods, the coupling effect of water discharge between cascade power plants has not been fully modeled. Irregular water discharge from upstream reservoirs may force downstream power plants to passively adjust their operation plans, further amplifying the risks of hydropower dispatch. Summary of the Invention

[0005] In view of the above-mentioned existing problems, the present invention provides a method, system, equipment and medium for modeling cascade hydropower.

[0006] This invention provides a method, system, equipment, and medium for modeling cascade hydropower to address the discrepancy between the actual water discharge patterns of hydropower plants and reality, i.e., water discharge occurring before the water level reaches the upper limit.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: In a first aspect, the present invention provides a method for modeling cascade hydropower, comprising: Obtain hydropower data from the hydropower plant, preprocess the hydropower data to obtain first hydropower data; Based on the first hydropower data, a day-ahead market clearing optimization model is constructed, and a first optimization is performed on each unit of the day-ahead market clearing optimization model to obtain a first optimization result; Based on the first optimization result, the output plan of each unit in the day-ahead market clearing optimization model is optimized a second time to obtain the second optimization result. The node price is calculated based on the second optimization result. The first optimization result, the second optimization result, and the node price are then combined to obtain the cascade hydropower optimization result, thus realizing the modeling of cascade hydropower.

[0008] As a preferred embodiment of the cascade hydropower modeling method described in this invention, the construction of the day-ahead market clearing optimization model includes: The objective function is to minimize the total cost of power generation, which includes the unit operating cost and the penalty cost for water wastage. The constraints include operational constraints and hydropower plant-specific constraints, which include at least hydropower water level control constraints and water discharge flow limit constraints.

[0009] As a preferred embodiment of the cascade hydropower modeling method described in this invention, the wastewater discharge flow constraint includes: By introducing a binary indicator variable, the permission of a hydropower plant to generate water discharge flow is correlated with whether the reservoir water level at the end of the corresponding time period reaches the preset upper limit of water level control. Only when the indication allows water discharge can the water discharge flow be a non-zero value.

[0010] The beneficial effects of this preferred technical solution are that by introducing a binary indicator variable, the water discharge flow is strictly limited to occur only when the water level reaches the upper limit, effectively avoiding unreasonable water discharge and improving the rationality and stability of cascade hydropower scheduling.

[0011] As a preferred embodiment of the cascade hydropower modeling method described in this invention, the first optimization includes: The unit combination of the day-ahead market clearing optimization model is optimized to determine the start-up and shutdown status of each unit within the optimization period, and at the same time, the values ​​of the binary indicator variables corresponding to each hydropower plant in each time period are solved. Unit combination optimization is carried out under the conditions of satisfying operational constraints and specific constraints of the hydropower plant, and the first optimization results are obtained, including unit start-up and shutdown plans and preliminary water discharge indications.

[0012] The beneficial effect of this preferred technical solution is that, by optimizing the unit combination and water discharge indicator variables, it ensures that the start-up and shutdown of the units are reasonably arranged under the specific constraints of operation and hydropower plant, and effectively controls water discharge behavior.

[0013] As a preferred embodiment of the cascade hydropower modeling method described in this invention, the second optimization includes: Based on the first optimization result, the start-up and shutdown status of the unit and the values ​​of the binary indicator variables are fixed; Based on the fixed start / stop status and water discharge indication, economic dispatch optimization is performed to re-optimize the output plan of all units, while keeping the water discharge flow limit constraint effective, thus obtaining the second optimization result.

[0014] The beneficial effects of this preferred technical solution are that by fixing the start-stop status and water discharge indication, the unit output can be further optimized, the water discharge flow restriction can be effectively limited, and the scheduling accuracy and reliability can be enhanced.

[0015] As a preferred embodiment of the cascade hydropower modeling method described in this invention, the calculation of nodal electricity prices includes: The unit output plan obtained based on economic dispatch optimization allows the unit output to vary within the neighborhood of the second optimization result, and the unit output of non-fixed units is fixed. Based on the unit output and the non-priceable unit output, the constrained shadow price is obtained. Based on the constrained shadow price, the marginal electricity price of the network node, i.e., the node price, is calculated.

[0016] As a preferred embodiment of the cascade hydropower modeling method described in this invention, the optimization results of the cascade hydropower include: The system integrates and outputs the combined status of generating units, the winning bid output of generating units for each time period, and the nodal electricity price. Extract and output the optimization process information of reservoir water level, power generation flow and wastewater flow for each hydropower plant in each time period within the optimization cycle.

[0017] Secondly, the present invention provides a cascade hydropower modeling system, comprising: The preprocessing module is used to acquire hydropower data from the hydropower plant, preprocess the hydropower data, and obtain the first hydropower data. The first optimization module is used to construct a day-ahead market clearing optimization model based on the first hydropower data, and to perform a first optimization on each unit of the day-ahead market clearing optimization model to obtain a first optimization result. The second optimization module is used to perform a second optimization on the output plan of each unit in the day-ahead market clearing optimization model based on the first optimization result, so as to obtain the second optimization result. The optimization output module is used to calculate the node electricity price based on the second optimization result, and to organize the first optimization result, the second optimization result and the node electricity price to obtain the cascade hydropower optimization result, thereby realizing the modeling of cascade hydropower.

[0018] Thirdly, the present invention provides a computer device, including a memory and a processor, wherein the memory stores a computer program, characterized in that the processor executes the computer program to implement the steps of the aforementioned cascade hydropower modeling method.

[0019] Fourthly, the present invention provides a computer-readable storage medium having a computer program stored thereon, characterized in that the computer program, when executed by a processor, implements the steps of the aforementioned cascade hydropower modeling method.

[0020] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention, by forcibly requiring water discharge to be triggered only when the water level approaches the upper limit, avoids unreasonable premature water discharge, making the optimization results of this invention closer to the physical law of hydropower plants storing water first and then discharging it. Simultaneously, the water discharge behavior of the upstream reservoir in this invention is strictly limited by water level constraints, which can reduce the impact of sudden water discharge on downstream power stations caused by traditional methods, and improve the overall stability of cascade scheduling. Furthermore, this invention, by explicitly constraining the water discharge triggering conditions, avoids the model sacrificing the rationality requirements of water discharge to meet other high-priority constraints, thereby reducing the risk of drastic water level fluctuations and sudden changes in downstream flow. Traditional cascade hydropower optimization models usually only indirectly limit the water discharge flow through the water discharge penalty term in the objective function, causing the water discharge behavior of traditional methods to violate actual operating laws. Therefore, compared with traditional cascade hydropower optimization models, the method provided by this invention, while ensuring the minimization of water discharge, takes into account both water level safety and the physical feasibility of cascade operation, providing a more reliable decision-making basis for hydropower optimization. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. 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.

[0022] Figure 1 This is a schematic diagram of the overall process logic of a cascade hydropower modeling method provided in one embodiment of the present invention.

[0023] Figure 2 This invention provides a conventional modeling method for cascade hydropower modeling, showing the changes in water level, power generation flow, and wastewater discharge of hydropower plant A over 24 hours.

[0024] Figure 3 This invention provides a cascade hydropower modeling method that considers the changes in water level, power generation flow, and wastewater flow of hydropower plant A within 24 hours under the constraint of wastewater discharge flow. Detailed Implementation

[0025] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0026] Example 1, referring to Figure 1 As an embodiment of the present invention, a method for modeling cascade hydropower is provided, comprising: S100: Obtain hydropower data from the hydropower plant, preprocess the hydropower data, and obtain the first hydropower data; In this embodiment of the invention, the hydropower data of the hydropower plant includes relevant parameters and constraint data of the hydropower plant obtained from the dispatching department, including the hydropower plant water consumption rate (unit: m3 / MWh), reservoir water surface area (unit: m2), natural inflow (unit: m3), initial water level and upper and lower limits of water level (unit: m), and upstream and downstream relationships of cascade hydropower.

[0027] Preprocessing includes feasibility verification based on the read hydropower data, including verification of the initial water level and upper and lower limits of the reservoir, verification of the upper and lower limits of the hydropower plant and hydropower unit output, and verification of the hydropower plant's power constraints. The main purpose of this stage is to check for potential data errors before modeling and solving, and to provide timely feedback to the on-duty personnel.

[0028] S200: Construct a day-ahead market clearing optimization model based on the first hydropower data, and perform the first optimization on each unit of the day-ahead market clearing optimization model to obtain the first optimization result; S300: Based on the first optimization result, the output plan of each unit in the day-ahead market clearing optimization model is optimized a second time to obtain the second optimization result; S400: Calculate the node electricity price based on the second optimization result, and organize the first optimization result, the second optimization result and the node electricity price to obtain the cascade hydropower optimization result, thereby realizing the modeling of cascade hydropower.

[0029] In one alternative embodiment, the nodal electricity price can be calculated as a nodal electricity price based on DC power flow. A DC power flow equation is constructed, the relationship between nodal injected power and line power flow is linearized, DC power flow constraints are introduced into the optimization model, and the Lagrange multipliers of each node are obtained by solving. These Lagrange multipliers are used as nodal electricity prices to reflect the marginal cost of the nodes. In another alternative embodiment, the calculation of nodal electricity price can also be based on AC power flow calculation. A complete AC power flow equation is constructed, considering the nonlinear relationship between nodal injected power and line power flow. AC power flow constraints are introduced into the optimization model, and the dual variables of each node are solved. These dual variables are used as nodal electricity price to reflect the marginal cost of the node. In this embodiment of the invention, calculating the nodal electricity price includes calculating the nodal electricity price based on the constrained shadow price; Specifically, the day-ahead market clearing optimization model is solved to obtain the shadow price of the network constraint. Based on the constraint shadow price, combined with the unit output and the fixed output of the non-priceable units, the marginal electricity price of each network node, i.e., the node price, is calculated.

[0030] It should be noted that it can accurately reflect the impact of network constraints on nodal electricity prices and is suitable for day-ahead market clearing and real-time dispatch scenarios in complex power systems.

[0031] It should also be noted that this invention achieves refined modeling of cascade hydropower through data preprocessing, phased optimization, and nodal pricing calculation. This invention rigorously verifies hydropower data to ensure its accuracy and reliability. This invention optimizes unit combination and output plans in stages, effectively controlling water wastage and improving hydropower plant operating efficiency. This invention accurately calculates nodal pricing based on the optimization results, providing a scientific basis for market clearing. This invention significantly improves the rationality and economy of cascade hydropower dispatching, reduces operational risks, and enhances system stability.

[0032] In this embodiment of the invention, step S200 includes the following sub-steps A1-A3; In A1: The objective function is to minimize the total cost of power generation. The objective function includes the unit operating cost and the penalty cost for water wastage. In A2: Set constraints including operational constraints and hydropower plant-specific constraints. Hydropower plant-specific constraints include at least hydropower water level control constraints and water discharge flow limit constraints. In A3: By introducing a binary indicator variable, whether the hydropower plant is allowed to generate water discharge flow is associated with whether the reservoir water level at the end of the corresponding time period reaches the preset water level control upper limit. The water discharge flow can only be a non-zero value when the indication allows water discharge.

[0033] In one alternative embodiment, the specific constraint on the hydropower plant can be the daily power generation constraint of the hydropower plant, requiring the total power generation of the hydropower plant within the optimization period to fall between the lower limit and the upper limit given by the water dispatching department, thereby combining the allocation of water resources in the reservoir with the clearing of the electricity market. In another alternative embodiment, the specific constraint of the hydropower plant can also be the head effect, where the power generation efficiency (water consumption rate) of the hydropower unit is related to the current water level (head) of the reservoir, rather than being fixed. In this embodiment of the invention, the specific constraints of the hydropower plant include hydropower level control constraints and wastewater discharge flow restriction constraints.

[0034] In the Unit Combination (SCUC) phase, all unit and hydropower plant related variables are defined, and an objective function for minimizing power generation cost is constructed. Generally, constraints such as system load balance, system reserve, unit output upper and lower limits, unit ramp-up, hydropower plant power generation, hydropower plant water level control, and network security are considered, and the winning output of the unit is calculated in each time period.

[0035] Specifically, the objective function, which minimizes the total cost of power generation in the system, is expressed as: in, The total number of time periods. The total number of units. , The units During the period Operating costs and start-up costs, It is a multi-segment linear function related to the unit output. For the unit During the period of efforts, The network flow constraint relaxation penalty factor is used for market clearing optimization. Cross-sections Forward and reverse current slack variables, The total number of cross-sections. For the relaxation penalty factor of abandoned water flow used for market clearing optimization, For hydropower plants during the period The discharge flow rate, It is a collection of hydropower plants.

[0036] The water volume matching constraints for cascade hydropower are simplified into wastewater discharge flow and hydropower water level control constraints. The wastewater discharge flow constraint refers to the actual wastewater discharge flow of the hydropower unit / unit within a certain time period, while the hydropower water level control constraint requires the water level of the hydropower station to be controlled within the required upper and lower limits within a certain time period. To improve day-ahead market clearing efficiency, the hydropower model makes the following assumptions: during the day-ahead clearing period, the water consumption rate of the hydropower station remains constant; during the day-ahead clearing period, the relationship between the water level and storage capacity of the hydropower station is linear, i.e., the reservoir surface area remains constant; and the lag time between day-ahead hydropower stations is independent of the downstream discharge flow of the upstream hydropower station.

[0037] During the SCUC (Scheduled Combined Unit) phase, the wastewater discharge flow limit constraint is expressed as follows: in, For the hydropower plant The water level at the end of the period, For the hydropower plants determined by the Water Resources Department The upper limit of water level control requirements at the end of the time period. For the hydropower plant The amount of water discharged during a given period It is a 0 / 1 integer variable. For hydropower plants during the period Allowing for the generation of wastewater flow, the following is derived: This means that water can only be discharged when the optimized water level reaches the upper limit. For hydropower plants during the period The water discharge rate is 0. It is a very large positive number.

[0038] Hydropower water level control constraints include the following requirements for the initial and final water levels of each reservoir at different times to ensure water level balance: Current initial water level - final water level = (power generation flow + water discharge flow) / water surface area; Current initial water level - previous final water level = (natural inflow + upstream reservoir power generation flow + upstream reservoir water discharge flow) / water surface area. Integrating the equations, we obtain the hydropower water level control constraints, namely the upper and lower limits of the reservoir water level constraints for hydropower plants, as follows: in, For hydropower stations determined by the Water Resources Management Department during the specified time period The upper and lower limits of the final water level control requirements. This represents the initial water level of the hydroelectric power station at midnight the following day. The water consumption rate of the hydropower station. The water surface area of ​​the reservoir of the hydroelectric power station. For the hydropower station during the period Natural water flow For the hydropower station during the period of efforts, For the hydropower station during the period The discharge flow rate, It is the upstream hydropower station of the hydropower station. For the upstream delay time faced by the hydropower station, Upstream hydropower station During the period The discharge flow rate.

[0039] Other constraints include system load balance constraints, system reserve constraints, unit output upper and lower limits, unit ramping, hydropower plant output and power constraints, and network constraints.

[0040] For each time period The load balance constraint is expressed as: in, For the unit During the period of efforts, For connecting lines During the period The planned power (input is positive, output is negative). The total number of connecting lines, for System load during a given time period.

[0041] The system's standby constraint requires that the total daily uptime capacity must meet the system's minimum standby capacity, expressed as follows: in, For the unit During the period Minimum output, For time period The system's negative backup capacity requirements.

[0042] The upper and lower limits of unit output, represented in the SCUC stage, are as follows: During the SCUC phase, when the unit is climbing, whether going uphill or downhill, the required climbing rate must be met, expressed as follows: in, For the unit Maximum uphill speed, For the unit Maximum downhill / climbing speed.

[0043] The power output constraint and power consumption constraint of a hydropower plant are as follows: The power output of a hydropower plant equals the total output of its hydropower units, expressed as: Based on the minimum and maximum power limits and average power calculated from the water level parameters of the water dispatch system, the winning bid power in the day-ahead electricity market should meet the power constraints of the power generation unit.

[0044] in, The total number of time periods on day D. and These represent the lower and upper limits of the hydropower plant's electricity generation on day D, respectively.

[0045] Network constraints, including line flow constraints, are represented as follows: in, For the line The limit of current transmission, For the unit The node is connected to the line The generator output power transfer distribution factor, The number of nodes in the system. For nodes For the line The generator output power transfer distribution factor, For nodes exist Bus load value for the time period The lines are respectively The positive and negative current slack variables.

[0046] Considering the power flow constraints at the critical section, this constraint is expressed as: in, cross-section The limit of current transmission, For the unit The node is located on the cross section The generator output power transfer distribution factor, For connecting lines The node is located on the cross section The generator output power transfer distribution factor, For nodes cross section The generator output power transfer distribution factor, Cross-sections The positive and negative current slack variables.

[0047] It should be noted that by introducing constraints on water discharge flow and hydropower water level control, the unit combination and output plan are optimized, which effectively reduces unreasonable water discharge, improves the operating efficiency and economy of cascade hydropower, and enhances the stability and reliability of system scheduling.

[0048] In this embodiment of the invention, after completing steps A1-A3, step S200 further includes steps A4-A5; In A4: Optimize the unit combination of the day-ahead market clearing optimization model, determine the start-up and shutdown status of each unit within the optimization period, and simultaneously solve for the values ​​of the binary indicator variables corresponding to each hydropower plant in each time period. In A5: Unit combination optimization is carried out under the conditions of satisfying operational constraints and hydropower plant-specific constraints, and the first optimization result is obtained, which includes unit start-up and shutdown plans and preliminary water discharge indications.

[0049] In an optional embodiment, the first optimization can be a mixed integer programming method, which treats the unit start-up and shutdown variables and the hydropower wastewater indication variables as a unified set of integer decision variables, and performs a one-time collaborative optimization under the condition of satisfying all constraints. In another alternative embodiment, the first optimization may also be to adopt a decomposition or iterative strategy, first ignoring some complex coupling constraints to solve a preliminary unit combination scheme, and then based on this scheme, fix some variables and further optimize the details of hydropower operation; or iterate between hydropower and thermal power problems until the scheme converges.

[0050] In this embodiment of the invention, the first optimization includes unit combination optimization; Specifically, in the Economic Dispatch (SCED) phase, the constraints considered are basically the same as in the SCUC phase. The unit determines its start-up and shutdown status based on the SCUC, and other 01 indicator variables will also be fixed based on the SCUC optimization results. The winning output of the unit in each time period is used as the final optimization result.

[0051] During the Scheduled Economic Dispatch (SCED) phase, the constraint on the discharge flow rate is expressed as follows: Since the wastewater discharge flow constraint includes the modeling of 01 indicator variables, the wastewater discharge indicator variables will be fixed based on the SCUC optimization results. To ensure that water is only released when the water level reaches the upper limit, similarly, the water release flow rate is fixed based on the SCUC results, and the output of the hydropower plant and other units is further optimized.

[0052] Other constraints, during the Economic Dispatch (SCED) phase, are expressed as follows: For the power generation units that are shut down in the SCUC optimization results All values ​​are set to 0.

[0053] When the generator unit is climbing an incline, whether going uphill or downhill, the required rate of climb must be met, as expressed as: in, For the unit Maximum uphill speed, For the unit Maximum downhill / climbing speed.

[0054] It should be noted that during the economic dispatch (SCED) phase, the water discharge indicator variables and unit start-up and shutdown status are fixed to further optimize unit output, ensure the effectiveness of water discharge flow restriction, and improve the operating efficiency and dispatch accuracy of hydropower plants.

[0055] In this embodiment of the invention, step S300 includes the following sub-steps B1-B2; In B1: Based on the first optimization result, the start-up and shutdown status of the unit and the values ​​of the binary indicator variables are fixed; In B2: Based on the fixed start-stop status and water discharge indication, economic dispatch optimization is performed to re-optimize the output plan of all units, while keeping the water discharge flow limit constraint effective, and the second optimization result is obtained.

[0056] In an optional embodiment, fixing the values ​​of the unit's start-up and shutdown status and the binary indicator variable can be achieved by taking the values ​​of the unit's start-up and shutdown status and the water discharge indicator variable obtained from the first optimization as unchangeable hard boundaries and directly placing them into the upper and lower limits of the variable values ​​in the economic dispatch model, so that they remain strictly unchanged during the optimization process. In another alternative embodiment, fixing the values ​​of the unit's start-up / shutdown status and the binary indicator variables can also be achieved by using the first optimization result as a benchmark or center value, but allowing for fine-tuning during economic dispatch. A small slack interval or penalty term can be set for the start-up / shutdown status or water discharge indication, allowing for minor adjustments at an additional cost. In this embodiment of the invention, fixing the start-up and shutdown status of the unit and the values ​​of the binary indicator variables includes the unit output varying within a small range near the SCED optimization result, and the fixed output of the non-pricing unit. During the nodal pricing (LPC) phase, the unit output varies within a small range around the SCED optimization results, while the output of non-pricing units remains fixed. The constrained shadow price is then obtained and the nodal price is further calculated.

[0057] Specifically, in the nodal pricing (LPC) phase, the constraints on water discharge flow are consistent with those in the economic dispatch (SCED) phase; During the nodal pricing (LPC) phase, other constraints, including upper and lower limits on unit output, are expressed as follows: For the units that are shut down according to the SCUC optimization results All values ​​are set to zero; for units that cannot be priced, All units are selected from the SCED optimization results. During the period The winning bid output; for priced units, The following values ​​are represented as: in, This represents the percentage in the LMP model that allows units to deviate from the day-ahead SCED optimization results. , These represent the minimum and maximum output of the unit in the current SCED model, respectively.

[0058] During the Levelized Pricing (LPC) phase, the unit ramping constraints are consistent with those during the Economic Dispatch (SCED) phase.

[0059] It should be noted that during the nodal pricing (LPC) phase, by fixing the unit start-up and shutdown status and using binary indicator variables, the unit output is allowed to be slightly adjusted near the SCED optimization results, while strictly controlling the water discharge limit, further optimizing the output plan and calculating the nodal pricing. This invention can maintain the stability of the optimization results while flexibly adapting to market changes, improving the accuracy of nodal pricing calculation and the flexibility of economic dispatch.

[0060] In this embodiment of the invention, step S400 includes the following sub-steps C1-C4; In C1: Based on the unit output plan obtained from economic dispatch optimization, the unit output is allowed to vary within the neighborhood of the second optimization result, and the unit output of non-pricing units is fixed. In C2: Based on the unit output and the non-priceable unit output, the constrained shadow price is obtained. Based on the constrained shadow price, the marginal electricity price of the network node, i.e., the node price, is calculated.

[0061] In C3: integrate the output of unit combination status, unit bid output for each time period, and nodal electricity price; In C4: Extract and output the optimization process information of reservoir water level, power generation flow and wastewater flow for each hydropower plant in each time period during the optimization cycle.

[0062] In this embodiment of the invention, during the result output stage, in addition to outputting the unit combination results based on the SCUC stage and the conventional optimization results such as the unit output plan and clearing price based on the solution results of the SCED stage, the optimization results of cascade hydropower will also be sorted and output, including hydropower plant output, reservoir water level, reservoir power generation flow and water abandonment flow.

[0063] It should be noted that in the results output stage, this invention not only outputs conventional optimization results, but also compiles detailed optimization results for cascade hydropower, including key information such as hydropower plant output, reservoir water level, power generation flow and water discharge flow, providing a comprehensive decision-making basis for hydropower plant operation and improving scheduling transparency and management efficiency.

[0064] The above is a schematic scheme of a cascade hydropower modeling method according to this embodiment. It should be noted that the technical solution of this cascade hydropower modeling system and the technical solution of the cascade hydropower modeling method described above belong to the same concept. For details not described in detail in the technical solution of the cascade hydropower modeling system in this embodiment, please refer to the description of the technical solution of the cascade hydropower modeling method described above.

[0065] The cascade hydropower modeling system in this embodiment includes: The preprocessing module is used to acquire hydropower data from the hydropower plant, preprocess the hydropower data, and obtain the first hydropower data. The first optimization module is used to construct a day-ahead market clearing optimization model based on the first hydropower data, and to perform a first optimization on each unit of the day-ahead market clearing optimization model to obtain a first optimization result. The second optimization module is used to perform a second optimization on the output plan of each unit in the day-ahead market clearing optimization model based on the first optimization result, so as to obtain the second optimization result. The optimization output module is used to calculate the node electricity price based on the second optimization result, and to organize the first optimization result, the second optimization result and the node electricity price to obtain the cascade hydropower optimization result, thereby realizing the modeling of cascade hydropower.

[0066] This embodiment also provides a computer device suitable for cascade hydropower modeling, including: The system includes a memory and a processor. The memory stores computer-executable instructions, and the processor executes these instructions to implement a cascade hydropower modeling method as described in the above embodiments.

[0067] This embodiment also provides a storage medium on which a computer program is stored. When the program is executed by a processor, it implements a cascade hydropower modeling method as proposed in the above embodiment.

[0068] The storage medium proposed in this embodiment and the method for implementing cascade hydropower modeling proposed in the above embodiments belong to the same inventive concept. Technical details not described in detail in this embodiment can be found in the above embodiments, and this embodiment has the same beneficial effects as the above embodiments.

[0069] Based on the above description of the implementation methods, those skilled in the art can clearly understand that the present invention can be implemented using software and necessary general-purpose hardware, and of course, it can also be implemented using hardware. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk, or optical disk, etc., including several instructions to cause a computing device (which may be a personal computer, server, or network device, etc.) to execute the methods of the various embodiments of the present invention.

[0070] Example 2, refer to Figures 2-3 This embodiment differs from the first embodiment, providing a verification test for a cascade hydropower modeling method, and verifying and explaining the technical effects used in this method.

[0071] Based on a benchmark case (optimization period T=24, unit: hour), the traditional hydropower modeling method and the hydropower modeling method considering the limitation of water discharge flow were applied to solve the problem. The optimization results of a certain hydropower plant A were selected to plot the relationship between power generation flow, water discharge flow and water level over time, and the results were compared and analyzed.

[0072] like Figure 2 , Figure 3 As shown, under the traditional modeling method, A generated water discharge at 14:00 and 15:00 when the water level had not reached the upper limit.

[0073] Analyzing this situation, based on the reservoir water level balance, with the power generation flow of A remaining constant, the water discharge generated can increase the inflow to downstream hydropower plant B. The output of unit B can alleviate blockage at a certain section. Therefore, given that the power generation capacity of power plant B is limited by the reservoir's water volume, increasing the water discharge from A increases the inflow to B. Even if the water discharge incurs a penalty cost, the penalty cost is relatively higher due to network constraints in the objective function, meaning that ensuring grid safety has the highest priority, thus enabling A to discharge water.

[0074] Although the blockage at the cross-section was alleviated, the water level of Reservoir A was not at its upper limit before the water was released, which is obviously inconsistent with the actual operation mode of hydropower.

[0075] After considering the water discharge limit, hydropower plant A did not generate any water discharge, indicating that water discharge is only allowed when the water level reaches the upper limit. This effectively improves the generation of unreasonable water discharge compared to traditional methods.

[0076] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A stepped hydroelectric modeling method, characterized by, The method comprises the following steps: Obtaining water and electricity data of a hydropower plant, preprocessing the water and electricity data to obtain first water and electricity data; Constructing a day-ahead market clearing optimization model according to the first water and electricity data, and performing first optimization on each unit of the day-ahead market clearing optimization model to obtain a first optimization result; Based on the first optimization result, performing second optimization on the output plan of each unit in the day-ahead market clearing optimization model to obtain a second optimization result; According to the second optimization result, calculating a node electricity price, and arranging the first optimization result, the second optimization result and the node electricity price to obtain a cascade hydropower optimization result, thereby realizing modeling of the cascade hydropower.

2. A stepped hydroelectric modeling method as claimed in claim 1, wherein, The construction of the day-ahead market clearing optimization model comprises the following steps: Taking the minimum total generation cost as an objective function, the objective function comprising a unit operation cost and a water flow penalty cost; Setting constraint conditions comprising operation constraints and hydropower plant specific constraints, the hydropower plant specific constraints at least comprising water level control constraints and water flow limitation constraints.

3. A stepped hydroelectric modeling method as claimed in claim 2, wherein, The water flow limitation constraint comprises the following steps: By introducing a binary indicator variable, the water flow penalty cost is associated with whether the reservoir water level at the end of the corresponding period reaches a preset upper limit of the water level control, and the water flow can only be a non-zero value when the water flow penalty is allowed.

4. A stepped hydroelectric modeling method as claimed in claim 3, wherein, The first optimization comprises the following steps: Optimizing the unit combination of the day-ahead market clearing optimization model to determine the start-stop state of each unit in the optimization period, and simultaneously solving the value of the binary indicator variable corresponding to each hydropower plant in each period; The unit combination optimization is performed under the conditions of satisfying the operation constraints and the hydropower plant specific constraints to obtain the first optimization result comprising the unit start-stop plan and the preliminary water flow indicator.

5. A stepped hydroelectric modeling method as claimed in claim 4, wherein, The second optimization comprises the following steps: According to the first optimization result, fixing the start-stop state of the unit and the value of the binary indicator variable; Based on the fixed start-stop state and water flow indicator, performing economic dispatch optimization to re-optimize the output plan of all units while keeping the water flow limitation constraint effective, thereby obtaining the second optimization result.

6. A stepped hydroelectric modeling method as claimed in claim 5, wherein, The calculation of the node electricity price comprises the following steps: Based on the unit output plan obtained by the economic dispatch optimization, the unit output is allowed to change within the neighborhood range of the second optimization result, and the non-pricing unit output is fixed; Based on the unit output and the non-pricing unit output, the constraint shadow price is solved, and the marginal price of the network node, i.e. the node electricity price, is calculated based on the constraint shadow price.

7. A stepped hydroelectric modeling method as claimed in claim 6, wherein, The obtaining of the cascade hydropower optimization result comprises the following steps: Integrating the output unit combination state, the unit output in each period and the node electricity price; Extracting and outputting the optimization process information of the reservoir water level, the generation flow and the water flow of each hydropower plant in the optimization period.

8. A cascade hydropower modeling system applying a cascade hydropower modeling method according to any one of claims 1-7, characterized in that, The method comprises the following steps: A preprocessing module is configured to obtain water and electricity data of a hydropower plant, and preprocess the water and electricity data to obtain first water and electricity data; A first optimization module is configured to construct a day-ahead market clearing optimization model according to the first water and electricity data, and perform first optimization on each unit of the day-ahead market clearing optimization model to obtain a first optimization result; A second optimization module is configured to perform second optimization on the output plan of each unit in the day-ahead market clearing optimization model based on the first optimization result to obtain a second optimization result; A preprocessing module is configured to obtain water and electricity data of a hydropower plant, and preprocess the water and electricity data to obtain first water and electricity data; The optimization output module is used for calculating a node electricity price according to the second optimization result, and arranging the first optimization result, the second optimization result and the node electricity price to obtain a cascade hydropower optimization result, so as to realize modeling of the cascade hydropower.

9. A computer device, comprising: The method comprises the following steps: A memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to realize the steps of the cascade hydropower modeling method in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, A computer program is stored on the memory, and the computer program is executed by the processor to realize the steps of the cascade hydropower modeling method in any one of claims 1 to 7.

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