Cascade hydropower station combined dispatching optimization method and system, terminal and medium

Abstract

The invention discloses a cascade hydropower station combined dispatching optimization method and system, a terminal and a medium, and relates to the technical field of power dispatching, and the main points of the technical scheme are that primary dispatching is started when the total accumulated value of output fluctuation of all power stations reaches a fluctuation threshold value; selecting the power station with the output fluctuation direction consistent with the deviation direction between the actual output and the planned output of the cascade hydropower stations as a target power station; selecting the target power station corresponding to the maximum output fluctuation accumulated value as a dispatching power station; a dispatching function is established by taking reduction of output fluctuation of dispatching power stations and reduction of deviation between actual output and planned output of cascade hydropower stations as dispatching targets and combining basic constraint conditions of each stage of power stations participating in dispatching. According to the method, the output fluctuation can be reduced from the global angle of the cascade hydropower stations and the local angle of the single hydropower station at the same time, the random fluctuation response of the predicted load is more timely, and the stability and reliability of combined dispatching of the cascade hydropower stations are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electric power dispatching, and more specifically, to a method, system, terminal and medium for joint dispatching optimization of cascade hydropower stations. Background Art

[0002] The joint dispatching of cascade hydropower stations refers to the unified coordinated dispatching of a group of interconnected cascade reservoirs and hydropower stations and related engineering facilities in the basin. This dispatching method maximizes the role and benefits of each reservoir and hydropower station by optimizing dispatching. Its main dispatching goals include but are not limited to reducing water abandonment, improving operating head and smoothing output fluctuations. Among them, the impact of output fluctuations on the power grid is multifaceted, involving the stability of the power grid, power quality, planning, operation dispatching, economy and market, so the study of output fluctuations in cascade hydropower stations is very important for the safe and stable operation of the power grid.

[0003] At present, considering the loss of long-distance power transmission, each level of cascade hydropower station generally supplies power to the nearest area, and then allocates the actual output of each hydropower station based on the minimum output fluctuation between the actual output of each hydropower station and the predicted load. However, the output of cascade hydropower stations is jointly affected by the inflow of each hydropower station and the random fluctuation of the corresponding predicted load. In the short-term time scale, the actual output of each hydropower station is generally adjusted according to the fluctuation of the predicted load. It is easy to cause the overall output of the cascade power station to not match the overall inflow in the medium and long-term time scale, resulting in the residual flow of some hydropower stations unable to meet the basic water demand; in addition, the actual output of each hydropower station is not strongly correlated, and it is easy to cause the output of multiple hydropower stations to be frequently adjusted when the overall output of the cascade power station matches the overall load; in addition, the short-term time scale of each hydropower station is kept consistent, which is poor in timeliness and effect in reducing the output fluctuation of the entire cascade power station.

[0004] Therefore, how to study and design a joint dispatching optimization method, system, terminal and medium for cascade hydropower stations that can overcome the above-mentioned defects is a problem that we urgently need to solve. Summary of the invention

[0005] In order to address the deficiencies in the prior art, the purpose of the present invention is to provide a method, system, terminal and medium for optimizing the joint dispatching of cascade hydropower stations, which can flexibly select hydropower stations for output dispatching in a dynamically changing short-term time scale while gradually tending to a stable output of cascade hydropower stations in a medium- and long-term time scale, thereby being able to reduce output fluctuations from both the global perspective of cascade hydropower stations and the local perspective of a single hydropower station, and respond more promptly to random fluctuations in predicted loads, thereby effectively improving the stability and reliability of the joint dispatching of cascade hydropower stations.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions: In a first aspect, a method for optimizing joint dispatching of cascade hydropower stations is provided, comprising the following steps: Determine the planned output of cascade hydropower stations in the medium and long term; Analyze the output fluctuations of each level of the cascade hydropower station, and initiate a dispatch when the total cumulative value of the output fluctuations of all stations reaches the fluctuation threshold; When the dispatch is started, a power station whose output fluctuation direction is consistent with the deviation direction between the actual output and the planned output of the cascade hydropower station is selected as the target power station; The target power station corresponding to the maximum cumulative value of output fluctuation is selected as the dispatching power station for single dispatch; The dispatching goal is to reduce the output fluctuation of the dispatching power station and reduce the deviation between the actual output and the planned output of the cascade hydropower station, and establish a dispatching function in combination with the basic constraints of the dispatching of power stations at all levels; The actual output of the dispatching power station on a short-term time scale after a single dispatch is solved through the objective function.

[0007] Furthermore, the process of determining the planned output of the cascade hydropower stations in the medium and long term is specifically as follows: Determine the initial water level and steady-state water level of each power station in the cascade hydropower station. The steady-state water level is divided into the first water level that meets the water demand in the dry season and the second water level that meets the flood control demand in the flood season; Estimate the inflow of non-power station areas into the catchment areas corresponding to each level of power stations in the medium and long term; The power generation coefficient of each power station is determined according to the power generation parameters of each power station and the upstream and downstream relationship of each power station. The power generation parameters represent the power generation that can be converted into unit flow; With the goal of reaching the steady-state water level for each power station, the planned output of the cascade hydropower stations in the medium and long term is solved.

[0008] Furthermore, the expression for solving the planned output of the cascade hydropower station in the medium and long term time scale is specifically: ; in, It represents the planned output of cascade hydropower stations in the medium and long term. The cascade hydropower station includes n-level power stations. Indicates medium to long term time scale; It represents the inflow of non-power stations into the catchment area corresponding to the i-th power station in the medium and long term time scale; represents the initial water level of the i-th power station; represents the steady-state water level of the ith power station; represents the reservoir area corresponding to the i-th level power station; Represents the power generation parameters of the j-th power station.

[0009] Furthermore, the calculation process of the total cumulative value of the output fluctuations of all power stations is specifically as follows: The output fluctuation of a single power station is integrated and summed to obtain the cumulative value of the output fluctuation of a single power station. The output fluctuation is the absolute value or square of the difference between the actual output of the power station and the predicted load of the corresponding power supply area. The total cumulative value of the output fluctuations of all power stations is calculated by summing up the cumulative values ​​of the output fluctuations of each power station.

[0010] Furthermore, the expression for starting a dispatch when the total cumulative value of the output fluctuations of all power stations reaches the fluctuation threshold is: ; Where n represents the number of power stations in the cascade hydropower station; Indicates the starting time of output fluctuation accumulation; Indicates the cumulative duration of output fluctuation accumulation; represents the actual output of the i-th power station at time t; It represents the predicted load of the power supply area corresponding to the i-th power station at time t; Indicates the fluctuation threshold.

[0011] Furthermore, if the difference between the actual output of the power station and the predicted load of the corresponding power supply area is positive, the output fluctuation direction of the corresponding power station is positive; if the difference between the actual output of the power station and the predicted load of the corresponding power supply area is negative, the output fluctuation direction of the corresponding power station is negative. Also, if the difference between the actual output and the planned output of the cascade hydropower station is a positive value, then the direction of the deviation between the actual output and the planned output of the cascade hydropower station is a positive direction; if the difference between the actual output and the planned output of the cascade hydropower station is a negative value, then the direction of the deviation between the actual output and the planned output of the cascade hydropower station is a negative direction.

[0012] Furthermore, the expression of the scheduling function is specifically: ; in, represents the actual output of the dispatching power station D in the q+1th dispatching process of the cascade hydropower station; It represents the planned output of cascade hydropower stations in the medium and long term. The cascade hydropower station includes n-level power stations. Indicates medium to long term time scale; Indicates the number of times the i-th power station starts dispatching; It represents the actual output of the i-th power station at the k-th startup dispatch; represents the short-term time scale of the i-th power station when it starts dispatching at the kth time; Indicates the lower limit of the output of the i-th power station; represents the actual output of the i-th power station; represents the output upper limit of the i-th power station; represents the lower limit of the water level of the i-th power station; represents the actual water level of the i-th power station; represents the upper limit of the water level of the i-th power station; It represents the cumulative duration of the dispatching power station D during the qth dispatching process of the cascade hydropower station. The corresponding cumulative value of output fluctuation; It represents the cumulative duration of the dispatching power station D during the q+1th dispatching process of the cascade hydropower station. The corresponding cumulative value of output fluctuation; Indicates the cumulative duration of all target power stations during the qth dispatch of cascade hydropower stations The corresponding second largest output fluctuation cumulative value; represents the short-term time scale of the qth dispatch of cascade hydropower stations; It represents the total output of the cascade hydropower station after the qth dispatch is completed; represents the short-term time scale of the q+1th dispatch of the cascade hydropower stations; It represents the total output of the cascade hydropower station after the q+1th dispatch is completed; It indicates the number of times cascade hydropower stations are started and dispatched in the long term.

[0013] In a second aspect, a cascade hydropower station joint dispatch optimization system is provided, the system is used to implement a cascade hydropower station joint dispatch optimization method as described in any one of the first aspects, including: Output analysis module, used to determine the planned output of cascade hydropower stations in the medium and long term; Start the monitoring module, which is used to analyze the output fluctuations of each level of the cascade hydropower station and start a dispatch when the total cumulative value of the output fluctuations of all power stations reaches the fluctuation threshold; A target screening module is used to select, when scheduling is started, a power station whose output fluctuation direction of at least one power station is consistent with the deviation direction between the actual output and the planned output of the cascade hydropower station as a target power station; A dispatch selection module is used to select the target power station corresponding to the maximum cumulative value of output fluctuation as the dispatch power station for single dispatch; Function building module, which is used to reduce the output fluctuation of the dispatching power station and reduce the deviation between the actual output and the planned output of the cascade hydropower station as the dispatching target, and establish the dispatching function in combination with the basic constraint conditions of the power stations at all levels participating in the dispatching; The output optimization module is used to solve the actual output of the dispatching power station in the short term after a single dispatch through the objective function.

[0014] In a third aspect, a computer terminal is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, a method for optimizing the joint dispatching of cascade hydropower stations as described in any one of the first aspects is implemented.

[0015] In the third and fourth aspects, a computer-readable medium is provided, on which a computer program is stored, and the computer program is executed by a processor to implement a method for optimizing the joint scheduling of cascade hydropower stations as described in any one of the first aspects.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention provides a method for optimizing the joint dispatching of cascade hydropower stations. While making the cascade hydropower stations gradually tend to stabilize their output in the medium and long term, the hydropower stations are flexibly selected for output dispatching in the dynamically changing short-term time scale. The method can reduce output fluctuations from both the global perspective of the cascade hydropower stations and the local perspective of a single hydropower station, and respond more promptly to random fluctuations in the predicted load, thereby effectively improving the stability and reliability of the joint dispatching of cascade hydropower stations. 2. When determining the planned output of cascade hydropower stations in the medium and long term, the present invention comprehensively considers the initial water level and basic flow requirements of each level of power stations, and can automatically balance the risk resistance performance of cascade hydropower stations in various medium and long term time scales; 3. The present invention first independently calculates the cumulative value of output fluctuation of a single power station, and then calculates the total cumulative value of output fluctuation of all power stations by the sum of the cumulative values ​​of output fluctuation of each power station, which can automatically identify the incremental phenomenon of long-distance power transmission when the supply and demand of cascade hydropower stations are balanced; 4. In the joint dispatching, the present invention takes the output fluctuation of a single hydropower station as the direct optimization target, and then iteratively optimizes the output fluctuation of each hydropower station to achieve the overall output optimization of the cascade hydropower station. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings: Figure 1 is a flow chart of Embodiment 1 of the present invention; Figure 2 It is a system block diagram in Example 2 of the present invention. DETAILED DESCRIPTION

[0018] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0019] Embodiment 1: A method for optimizing the joint dispatching of cascade hydropower stations, such as Figure 1 As shown, the following steps are included: S1: Determine the planned output of cascade hydropower stations in the medium and long term; S2: Analyze the output fluctuations of each level of the cascade hydropower station, and initiate a dispatch when the total cumulative value of the output fluctuations of all power stations reaches the fluctuation threshold; S3: When the dispatch is started, a power station whose output fluctuation direction is consistent with the deviation direction between the actual output and the planned output of the cascade hydropower station is selected as the target power station; S4: Select the target power station corresponding to the maximum cumulative value of output fluctuation as the dispatching power station for single dispatch; S5: Taking reducing the output fluctuation of the dispatching power station and reducing the deviation between the actual output and the planned output of the cascade hydropower station as the dispatching target, and establishing the dispatching function in combination with the basic constraint conditions of the power stations at all levels participating in the dispatching; S6: The actual output of the dispatching power station in the short term after a single dispatch is solved through the objective function.

[0020] In step S1, the planned output of the cascade hydropower station in the medium and long term time scale can be solved by using a traditional model, for example, by minimizing the fluctuation between the overall output of the cascade hydropower station and the overall predicted load.

[0021] In addition, the planned output of cascade hydropower stations in the medium and long term can also be solved by comprehensively considering the initial water level and basic flow requirements of each level of power stations.

[0022] Specifically, the process of determining the planned output of cascade hydropower stations in the medium and long term time scale is as follows: determine the initial water level and steady-state water level of each level in the cascade hydropower station, the steady-state water level is divided into the first water level that meets the water demand in the dry season and the second water level that meets the flood control demand in the flood season; estimate the inflow between non-power stations into the confluence area corresponding to each level of power station in the medium and long term time scale; determine the power generation coefficient of each power station according to the power generation parameters of each power station and the upstream and downstream relationships of each power station, the power generation parameters represent the amount of power that can be converted per unit flow; solve the planned output of the cascade hydropower station in the medium and long term time scale with the goal of the final water level of each power station reaching the steady-state water level.

[0023] It should be noted that the specific value of the steady-state water level can be flexibly selected according to different seasons. The inflow between non-power stations refers to the flow that does not include the flow that flows into the next hydropower station after generating electricity at the upper hydropower station.

[0024] For example, the expression for solving the planned output of cascade hydropower stations in the medium and long term is: ; in, It represents the planned output of cascade hydropower stations in the medium and long term. The cascade hydropower station includes n-level power stations. Indicates medium to long term time scale; It represents the inflow of non-power stations into the catchment area corresponding to the i-th power station in the medium and long term time scale; represents the initial water level of the i-th power station; represents the steady-state water level of the ith power station; represents the reservoir area corresponding to the i-th level power station; Represents the power generation parameters of the j-th power station.

[0025] In step S2, the calculation process of the total cumulative value of the output fluctuations of all power stations is specifically as follows: the output fluctuations of a single power station are integrated and summed to obtain the cumulative value of the output fluctuations of a single power station, where the output fluctuation is the absolute value or square of the difference between the actual output of the power station and the predicted load of the corresponding power supply area; the total cumulative value of the output fluctuations of all power stations is calculated by the sum of the cumulative values ​​of the output fluctuations of each power station.

[0026] For example, the expression for starting a dispatch when the total cumulative value of the output fluctuations of all power stations reaches the fluctuation threshold is: ; Where n represents the number of power stations in the cascade hydropower station; Indicates the starting time of output fluctuation accumulation; Indicates the cumulative duration of output fluctuation accumulation; represents the actual output of the i-th power station at time t; It represents the predicted load of the power supply area corresponding to the i-th power station at time t; Indicates the fluctuation threshold.

[0027] In step S3, if the difference between the actual output of the power station and the predicted load of the corresponding power supply area is a positive value, the output fluctuation direction of the corresponding power station is a positive direction; if the difference between the actual output of the power station and the predicted load of the corresponding power supply area is a negative value, the output fluctuation direction of the corresponding power station is a negative direction.

[0028] If the difference between the actual output and the planned output of the cascade hydropower station is a positive value, the deviation direction between the actual output and the planned output of the cascade hydropower station is in the positive direction; if the difference between the actual output and the planned output of the cascade hydropower station is a negative value, the deviation direction between the actual output and the planned output of the cascade hydropower station is in the negative direction.

[0029] It should be noted that only when the output fluctuation direction and the deviation direction are both negative or both positive, the corresponding hydropower station can be regarded as the target power station.

[0030] In step S4, it is assumed that there are three hydropower stations A, B, and C. The cumulative output fluctuation values ​​of the three hydropower stations A, B, and C within a certain period of time are respectively , , , using a unified basic unit quantity, the output fluctuation directions of the three power stations A, B, and C are negative, positive, and negative, respectively.

[0031] If the difference between the actual output of the cascade hydropower station (here corresponds to the sum of the output from the start time of the medium- and long-term time scale to the current time) and the planned output (here corresponds to the sum of the output from the start time of the medium- and long-term time scale to the current time) is positive, it means that the output is large and the deviation direction is positive. At this time, only power station B meets the requirements and is regarded as a dispatching power station for dispatching. The output of power station B can be reduced so that the cumulative value of output fluctuation is adjusted from 4 to 3 in the same time.

[0032] If the difference between the actual output of the cascade hydropower station (here corresponds to the sum of the output from the start time of the medium- and long-term time scale to the current time) and the planned output (here corresponds to the sum of the output from the start time of the medium- and long-term time scale to the current time) is a negative value, it means that the output is small and the deviation direction is negative. At this time, power stations A and C meet the requirements, and power stations A and C are both regarded as target power stations, but the cumulative value of the output fluctuation of power station A is large, so power station A is regarded as a dispatching power station for dispatching, and the output of power station B can be increased, so that the cumulative value of the output fluctuation is equal to 1 / 2 in the same time. Adjust to not exceed .

[0033] In step S5, the expression of the scheduling function is specifically: ; in, represents the actual output of the dispatching power station D in the q+1th dispatching process of the cascade hydropower station; It represents the planned output of cascade hydropower stations in the medium and long term. The cascade hydropower station includes n-level power stations. Indicates medium to long term time scale; Indicates the number of times the i-th power station starts dispatching; It represents the actual output of the i-th power station at the k-th startup dispatch; represents the short-term time scale of the i-th power station when it starts dispatching at the kth time; Indicates the lower limit of the output of the i-th power station; represents the actual output of the i-th power station; represents the output upper limit of the i-th power station; represents the lower limit of the water level of the i-th power station; represents the actual water level of the ith power station; represents the upper limit of the water level of the i-th power station; It represents the cumulative duration of the dispatching power station D during the qth dispatching process of the cascade hydropower station. The corresponding cumulative value of output fluctuation; It represents the cumulative duration of the dispatching power station D during the q+1th dispatching process of the cascade hydropower station. The corresponding cumulative value of output fluctuation; Indicates the cumulative duration of all target power stations during the qth dispatch of cascade hydropower stations The corresponding second largest output fluctuation cumulative value; represents the short-term time scale of the qth dispatch of cascade hydropower stations; It represents the total output of the cascade hydropower station after the qth dispatch is completed; represents the short-term time scale of the q+1th dispatch of the cascade hydropower stations; It represents the total output of the cascade hydropower station after the q+1th dispatch is completed; It indicates the number of times cascade hydropower stations are started and dispatched in the long term.

[0034] Embodiment 2: A cascade hydropower station joint dispatch optimization system, the system is used to implement a cascade hydropower station joint dispatch optimization method recorded in embodiment 1, such as Figure 2 As shown, it includes an output analysis module, a startup monitoring module, a target screening module, a scheduling selection module, a function construction module and an output optimization module.

[0035] Among them, the output analysis module is used to determine the planned output of the cascade hydropower station in the medium and long term; the start-up monitoring module is used to analyze the output fluctuations of each level of the cascade hydropower station, and start a dispatch when the total cumulative value of the output fluctuations of all power stations reaches the fluctuation threshold; the target screening module is used to select at least one power station whose output fluctuation direction is consistent with the deviation direction between the actual output and the planned output of the cascade hydropower station as the target power station when the dispatch is started; the dispatch selection module is used to select the target power station corresponding to the maximum cumulative value of output fluctuation as the dispatch power station for a single dispatch; the function construction module is used to reduce the output fluctuation of the dispatch power station and reduce the deviation between the actual output and the planned output of the cascade hydropower station as the dispatch target, and establish the dispatch function in combination with the basic constraints of the dispatch of each level of power stations; the output optimization module is used to solve the actual output of the dispatch power station on a short-term time scale after a single dispatch through the objective function.

[0036] The present invention also records a computer terminal, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, a method for optimizing the joint dispatching of cascade hydropower stations as described in Example 1 is implemented.

[0037] The present invention also records a computer-readable medium on which a computer program is stored. The computer program is executed by a processor to implement a method for optimizing the joint scheduling of cascade hydropower stations as described in Example 1.

[0038] Working principle: While making the cascade hydropower stations gradually tend to stable output in the medium and long term time scale, the present invention flexibly selects hydropower stations for output scheduling in the dynamically changing short-term time scale, which can reduce output fluctuations from both the global perspective of the cascade hydropower stations and the local perspective of a single hydropower station, and responds more promptly to random fluctuations in predicted loads, effectively improving the stability and reliability of the joint scheduling of cascade hydropower stations.

[0039] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0040] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0041] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0042] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0043] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for joint dispatching optimization of cascade hydropower stations, characterized in that: The following steps are involved: Determine the planned output of cascade hydropower stations in the medium and long term; Analyze the output fluctuations of each level of the cascade hydropower station, and initiate a dispatch when the total cumulative value of the output fluctuations of all stations reaches the fluctuation threshold; When the dispatch is started, a power station whose output fluctuation direction is consistent with the deviation direction between the actual output and the planned output of the cascade hydropower station is selected as the target power station; The target power station corresponding to the maximum cumulative value of output fluctuation is selected as the dispatching power station for single dispatch; The dispatching goal is to reduce the output fluctuation of the dispatching power station and reduce the deviation between the actual output and the planned output of the cascade hydropower station, and establish a dispatching function in combination with the basic constraints of the dispatching of power stations at all levels; The actual output of the dispatching power station on a short-term time scale after a single dispatch is solved through the objective function.

2. A cascade hydropower station joint dispatch optimization method according to claim 1, characterized in that: The process of determining the planned output of the cascade hydropower stations in the medium and long term is as follows: Determine the initial water level and steady-state water level of each power station in the cascade hydropower station. The steady-state water level is divided into the first water level that meets the water demand in the dry season and the second water level that meets the flood control demand in the flood season; Estimate the inflow of non-power station areas into the catchment areas corresponding to each level of power stations in the medium and long term; The power generation coefficient of each power station is determined according to the power generation parameters of each power station and the upstream and downstream relationship of each power station. The power generation parameters represent the power generation that can be converted into unit flow; With the goal of reaching the steady-state water level for each power station, the planned output of the cascade hydropower stations in the medium and long term is solved.

3. A cascade hydropower station joint dispatch optimization method according to claim 2, characterized in that: The specific expression for solving the planned output of the cascade hydropower station in the medium and long term time scale is: ； in, It represents the planned output of cascade hydropower stations in the medium and long term. The cascade hydropower station includes n-level power stations. Indicates medium to long term time scale; It represents the inflow of non-power stations into the catchment area corresponding to the i-th power station in the medium and long term time scale; represents the initial water level of the i-th power station; represents the steady-state water level of the ith power station; represents the reservoir area corresponding to the i-th level power station; Represents the power generation parameters of the j-th power station.

4. The method for joint dispatching optimization of cascade hydropower stations according to claim 1 is characterized in that: The calculation process of the total cumulative value of the output fluctuations of all power stations is specifically as follows: The output fluctuation of a single power station is integrated and summed to obtain the cumulative value of the output fluctuation of a single power station. The output fluctuation is the absolute value or square of the difference between the actual output of the power station and the predicted load of the corresponding power supply area. The total cumulative value of the output fluctuations of all power stations is calculated by summing up the cumulative values ​​of the output fluctuations of each power station.

5. The method for joint dispatching optimization of cascade hydropower stations according to claim 1 is characterized in that: The expression for starting a dispatch when the total cumulative value of the output fluctuations of all power stations reaches the fluctuation threshold is: ； Where n represents the number of power stations in the cascade hydropower station; Indicates the starting time of output fluctuation accumulation; Indicates the cumulative duration of output fluctuation accumulation; represents the actual output of the i-th power station at time t; It represents the predicted load of the power supply area corresponding to the i-th power station at time t; Indicates the fluctuation threshold.

6. The method for joint dispatching optimization of cascade hydropower stations according to claim 1 is characterized in that: If the difference between the actual output of the power station and the predicted load of the corresponding power supply area is positive, the output fluctuation direction of the corresponding power station is positive; if the difference between the actual output of the power station and the predicted load of the corresponding power supply area is negative, the output fluctuation direction of the corresponding power station is negative; Also, if the difference between the actual output and the planned output of the cascade hydropower station is a positive value, then the direction of the deviation between the actual output and the planned output of the cascade hydropower station is a positive direction; if the difference between the actual output and the planned output of the cascade hydropower station is a negative value, then the direction of the deviation between the actual output and the planned output of the cascade hydropower station is a negative direction.

7. The method for joint dispatching and optimizing cascade hydropower stations according to claim 1 is characterized in that: The expression of the scheduling function is specifically: ； in, represents the actual output of the dispatching power station D in the q+1th dispatching process of the cascade hydropower station; It represents the planned output of cascade hydropower stations in the medium and long term. The cascade hydropower station includes n-level power stations. Indicates medium to long term time scale; Indicates the number of times the i-th power station starts dispatching; It represents the actual output of the i-th power station at the k-th startup dispatch; represents the short-term time scale of the i-th power station when it starts dispatching at the kth time; Indicates the lower limit of the output of the i-th power station; represents the actual output of the i-th power station; represents the output upper limit of the i-th power station; represents the lower limit of the water level of the i-th power station; represents the actual water level of the ith power station; represents the upper limit of the water level of the i-th power station; It represents the cumulative duration of the dispatching power station D during the qth dispatching process of the cascade hydropower station. The corresponding cumulative value of output fluctuation; It represents the cumulative duration of the dispatching power station D during the q+1th dispatching process of the cascade hydropower station. The corresponding cumulative value of output fluctuation; Indicates the cumulative duration of all target power stations during the qth dispatch of cascade hydropower stations The corresponding second largest output fluctuation cumulative value; represents the short-term time scale of the qth dispatch of cascade hydropower stations; It represents the total output of the cascade hydropower station after the qth dispatch is completed; represents the short-term time scale of the q+1th dispatch of the cascade hydropower stations; It represents the total output of the cascade hydropower station after the q+1th dispatch is completed; It indicates the number of times cascade hydropower stations are started and dispatched in the long term.

8. A cascade hydropower station joint dispatch optimization system, characterized in that: The system is used to implement a cascade hydropower station joint dispatch optimization method as described in any one of claims 1 to 7, comprising: Output analysis module, used to determine the planned output of cascade hydropower stations in the medium and long term; Start the monitoring module, which is used to analyze the output fluctuations of each level of the cascade hydropower station and start a dispatch when the total cumulative value of the output fluctuations of all power stations reaches the fluctuation threshold; A target screening module is used to select, when scheduling is started, a power station whose output fluctuation direction of at least one power station is consistent with the deviation direction between the actual output and the planned output of the cascade hydropower station as a target power station; A dispatch selection module is used to select the target power station corresponding to the maximum cumulative value of output fluctuation as the dispatch power station for single dispatch; Function building module, which is used to reduce the output fluctuation of the dispatching power station and reduce the deviation between the actual output and the planned output of the cascade hydropower station as the dispatching target, and establish the dispatching function in combination with the basic constraint conditions of the power stations at all levels participating in the dispatching; The output optimization module is used to solve the actual output of the dispatching power station in the short term after a single dispatch through the objective function.

9. A computer terminal comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, a joint dispatch optimization method for cascade hydropower stations as described in any one of claims 1 to 7 is implemented.

10. A computer readable medium having a computer program stored thereon, characterized in that: The computer program is executed by a processor to implement a method for optimizing the joint dispatching of cascade hydropower stations as described in any one of claims 1 to 7.

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