A multi-stage cascade power station optimal collaborative operation method based on flow matching

Abstract

The application discloses a kind of multi-stage series power station optimization collaborative operation method based on flow matching, belong to water conservancy and hydropower technical field, including: the opening flow output model and flow matching interpolation model of multi-stage series power station are constructed;According to the total output of multi-stage series power station, determine the feasible interval of common flow of each power station operable unit combination;Through inverse interpolation function, the corresponding output and opening of each power station unit under different flow are solved, and the solution set matrix satisfying the requirement is obtained;Establish the collaborative optimization problem with the minimum total output deviation and the maximum overall efficiency of multi-stage series power station as target, and screen and optimize the feasible candidate solution;Obtain the optimal solution of each power station.The application can reduce unnecessary shutdown operation while ensuring the flow coordination of multi-stage series power station and the effective tracking of load instruction, improve the operation efficiency and regulation accuracy of multi-stage series power station, and provide technical support for safe, economic and flexible operation of multi-stage series hydropower station group.

Description

Technical Field

[0001] This invention belongs to the field of water conservancy and hydropower technology, specifically relating to a method for optimized and coordinated operation of multi-stage series power plants based on flow matching. Background Technology

[0002] To expand the supply of clean energy and ensure the efficient utilization of water resources in river basins, cascade hydropower stations generally adopt a multi-stage joint development model. However, current research on the hydraulic system mechanisms of such complex engineering layouts remains relatively weak, with a lack of understanding regarding the coordinated layout and structural coupling of three-stage series hydropower stations. Research on the coordinated operation mechanism of multi-stage series hydropower stations is also insufficient; their inherent hydraulic-electric coupling mechanism, dynamic response characteristics, and control strategies are not yet clear. The multi-stage series hydropower stations studied in this paper are deeply integrated into a hydro-wind-solar integrated energy system. During actual operation, they are susceptible to multiple factors such as fluctuations in wind and solar power output, uncertainties in water inflow, and changes in load demand, placing higher demands on the coordinated control and operational flexibility of the units. Therefore, it is urgent to construct a coordinated operation framework adapted to multi-energy complementary scenarios to improve the overall regulation capacity and operational reliability of multi-stage series hydropower stations.

[0003] Furthermore, the economic efficiency and high efficiency of power plant operation are core objectives throughout the entire project lifecycle and key factors that must be comprehensively considered during the early planning and design phases. How to optimize dispatching strategies and reduce water and energy curtailment while ensuring the safe, stable, and coordinated operation of multiple generating units has become an important issue that urgently needs to be explored. Summary of the Invention

[0004] This invention addresses the lack of a collaborative operation framework for multi-energy complementary scenarios in existing technologies, and the challenges of optimizing scheduling strategies and reducing water and energy curtailment while ensuring the safe, stable, and coordinated operation of multi-level units. Following the principles of "electricity-driven water supply," "flow matching," and "efficiency optimization," it provides a method for optimizing the collaborative operation of multi-level series power plants based on flow matching. This method constructs a collaborative operation model for multi-level series power plants, including operation, flow, and output models for each level of power plant and a flow matching interpolation model. It provides the total output variation range of the multi-level series power plants, and, combined with continuous flow constraints between upper and lower levels, determines the feasible combination of operable units and common flow ranges for each level. By using an inverse interpolation function, it solves for the corresponding output and operation of units at different flow rates, obtaining a solution set matrix that meets the requirements. Under the conditions of flow matching and output constraints, it establishes a collaborative optimization problem with the objectives of minimizing the total output deviation and maximizing the overall efficiency of the multi-level series power plants, screening and selecting candidate solutions. Finally, it obtains the optimal unit configuration, single-unit load allocation, operation level, and optimal efficiency of the multi-level series power plants for each level.

[0005] According to one aspect of this specification, a method for optimized coordinated operation of multi-stage series power plants based on flow matching is provided, comprising:

[0006] Establish an operating flow-output model for a multi-stage series power plant to obtain the operating flow-output relationship between the units at each stage of the power plant.

[0007] Establish a flow matching interpolation model: Based on the relationship between the opening, flow and output of power generation units at all levels, establish the forward interpolation function and the inverse interpolation function between the unit opening, single unit flow and single unit output;

[0008] Based on the given target total output, the target total output range is determined by combining the preset allowable error. Then, based on the proportion of the target total output to the total rated output of the multi-stage series power stations, the number of working units of each power station is determined.

[0009] Based on the feasible range of common total flow under different combinations of the number of operating units, the total flow of each level of power station is determined by combining the flow matching interpolation model, and candidate solutions that satisfy the constraints of the series power station system are selected as feasible candidate solutions based on the deviation between the total flow of each level of power station; the feasible candidate solutions include the unit operation, single unit flow, single unit output and unit efficiency of each level of power station units.

[0010] The total output is obtained based on the output of a single unit, the total output error is obtained by combining the target total output, and the overall efficiency of the multi-stage series power station is obtained based on the unit efficiency.

[0011] An optimization problem is constructed with the dual objectives of minimizing the total output error and maximizing the overall efficiency of the multi-stage series power plants. The Pareto solution set obtained based on feasible candidate solutions is evaluated, and feasible candidate solutions for optimization and coordination are obtained based on the evaluation results. The optimized and coordinated operation results are then output.

[0012] As a further technical solution, the process of establishing the opening-degree flow output model includes:

[0013] Step 1.1: Based on the transient process calculation model, calibrate the opening flow and output models of each level of power plant unit;

[0014] Step 1.2: Obtain the flow rate and opening degree within the tolerance range according to the required output of each power station, and establish the solution set matrix;

[0015] Repeat steps 1.1 and 1.2 until the solution set matrix of the multi-stage series power station is obtained.

[0016] As a further technical solution, a forward interpolation function and an inverse interpolation function are established between unit opening, single-unit flow rate, and single-unit output, including:

[0017] Convert the output of a single unit into a percentage of output, and construct positive interpolation functions from the percentage of output to the flow rate of a single unit and from the percentage of output to the unit's operating degree.

[0018] Based on the interpolation results from output percentage to single-unit flow rate, sorting, deduplication, and monotonicity processing are performed to establish an inverse interpolation function from single-unit flow rate to output percentage; where the interpolation result refers to the encrypted output flow rate combination obtained after interpolation processing through the forward interpolation function.

[0019] As a further technical solution, the number of operating units in each power station is determined based on the proportion of the target total output to the total rated output of the multi-stage series power stations, including:

[0020] When the target total output is lower than the total rated output of the multi-stage series power stations, the power stations at each stage are allowed to operate at reduced capacity simultaneously.

[0021] When the target total output accounts for no less than a preset threshold of the total rated output of the multi-stage series power stations, each level of power station operates according to the nominal number of units available; the nominal number of units available refers to the participation of all normally operating units.

[0022] As a further technical solution, the calculation process for the unit efficiency is as follows:

[0023] Based on the current operating level of each power plant unit, extract the characteristic relationships of unit speed, unit flow rate, and unit torque at the corresponding operating level;

[0024] Based on the actual operating speed, runner diameter and head of the unit, the unit speed and unit flow rate under the actual operating conditions are calculated, and the predicted values ​​of unit flow rate and unit torque under the current operating conditions are determined by two-stage interpolation.

[0025] The actual torque is recovered from the unit torque, and the mechanical power is obtained by combining the angular velocity. At the same time, the hydraulic power is obtained by the flow rate, head, water density and gravitational acceleration, and the efficiency of each level of power station unit is obtained.

[0026] As a further technical solution, the process of obtaining the Pareto solution set includes:

[0027] Select candidate solutions from the feasible candidate solutions that satisfy the target total output range:

[0028] If there exists a candidate solution that satisfies the target total output range, it is directly used as the Pareto solution set.

[0029] As a further technical solution, if there is no candidate solution that satisfies the target total output range, then all candidate solutions are retained; among all retained candidate solutions, the candidate solution with the fewest shutdowns is selected as the Pareto solution set.

[0030] As a further technical solution, the constraints of the series power station system include flow matching constraints, output range constraints, and operating range constraints.

[0031] As a further technical solution, the optimized collaborative operation results include the number of units put into operation at each level of power station, the total common flow, the flow of a single unit at each level of power station, the operating degree of a unit at each level of power station, the output of a single unit at each level of power station, the total output of each level of power station, the efficiency of a unit at each level of power station, the overall efficiency of a multi-stage series power station, and the target total output error.

[0032] According to one aspect of this specification, a multi-stage series power plant optimization and collaborative operation system based on flow matching is provided to implement the aforementioned method for optimizing and collaborative operation of a multi-stage series power plant based on flow matching, comprising:

[0033] The first processing module is used to establish an opening-flow-output model for multi-stage series power plants and obtain the opening-flow-output relationship between the units of each stage of the power plant.

[0034] The second processing module is used to establish a flow matching interpolation model: based on the relationship between the opening, flow and output of the power plants at all levels, it establishes the forward interpolation function and the inverse interpolation function between the opening, flow and output of a single unit;

[0035] The third processing module is used to determine the target total output range based on the given target total output and the allowable error, and then determine the number of working units of each power station according to the proportion of the target total output to the total fixed output of the multi-stage series power station.

[0036] The fourth processing module is used to determine the total flow of each power station based on the common total flow feasible interval under different combinations of the number of operating units, combined with the flow matching interpolation model, and select candidate solutions that satisfy the constraints of the series power station system as feasible candidate solutions based on the deviation between the total flow of each power station. The feasible candidate solutions include the unit operation, single unit flow, single unit output and unit efficiency of each power station unit.

[0037] The fifth processing module is used to obtain the total output based on the output of a single unit, to obtain the total output error by combining the target total output, and to obtain the overall efficiency of the multi-stage series power station based on the unit efficiency.

[0038] The sixth processing module is used to construct an optimization problem with the dual objectives of minimizing the total output error and maximizing the overall efficiency of the multi-stage series power station, evaluate the Pareto solution set obtained based on feasible candidate solutions, obtain feasible candidate solutions for optimization and coordination based on the evaluation results, and output the optimization and coordination operation results.

[0039] Compared with the prior art, the beneficial effects of the present invention are:

[0040] 1. This invention realizes the collaborative allocation based on the common total flow constraint in multi-stage series power plants by constructing a positive interpolation function and an inverse interpolation function between the flow rate and the output percentage of a single unit, thus solving the problem of difficult accurate flow matching in multi-stage power plants in traditional methods.

[0041] 2. This invention achieves the overall retrieval of multi-level power plant collaborative operation schemes by unifying the unit number combination search, series flow consistency judgment, opening degree solution and output allocation into the same solution framework.

[0042] 3. This invention reduces mechanical disturbances and operational instability caused by frequent shutdowns by setting up a hierarchical screening mechanism that prioritizes the fewest shutdown actions, thereby improving the engineering feasibility of coordinated regulation of power plant groups.

[0043] 4. Through multi-objective optimization and evaluation, this invention can select the optimal solution that balances output error and efficiency of multi-stage series power plants in various feasible operating conditions, thereby improving the overall benefits of coordinated operation of power plants. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 A flowchart of a method for optimizing and coordinating the operation of multi-stage series power plants based on flow matching, provided in an embodiment of the present invention.

[0046] Figure 2 This is a schematic diagram of the layout of a multi-stage series power station provided in an embodiment of the present invention.

[0047] Figure 3 This is a schematic diagram of an optimized example provided in an embodiment of the present invention.

[0048] Figure 4 A schematic diagram of the surge tank water level in a three-stage power plant, illustrating the power distribution mode and flow matching mode provided in this embodiment of the invention.

[0049] Figure 5 This is a schematic diagram of the water levels in two regulating pools provided in an embodiment of the present invention. Detailed Implementation

[0050] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] like Figure 1As shown, this invention proposes an optimized and coordinated operation method for multi-stage series power plants based on flow matching, including: establishing an opening-flow-output model for the multi-stage series power plants to obtain the opening-flow-output relationship between the units at each level of the power plant; establishing a flow matching interpolation model, i.e., based on the opening-flow-output relationship between the units at each level of the power plant, establishing a forward interpolation function and an inverse interpolation function between the unit opening, single-unit flow, and single-unit output; determining the target total output range based on a given target total output (referring to the target total output to be achieved, determined by the initial total output and the total output variation range), combined with a preset allowable error, and then determining the number of working units at each level of the power plant based on the proportion of the target total output to the total rated output of the multi-stage series power plants; and determining the number of working units at each level of the power plant based on different working units. The feasible interval of the common total flow under the combination of the number of units is determined by combining the flow matching interpolation model to determine the total flow of each level of power station. Based on the deviation between the total flow of each level of power station, candidate solutions that satisfy the constraints of the series power station system are selected as feasible candidate solutions. The feasible candidate solutions include the unit operation, single unit flow, single unit output, and unit efficiency of each level of power station. The total output is obtained based on the single unit output, and the total output error is obtained by combining the target total output. The overall efficiency of the multi-level series power station is obtained based on the unit efficiency. An optimization problem is constructed with the dual objectives of minimizing the total output error and maximizing the overall efficiency of the multi-level series power station. The Pareto solution set obtained based on the feasible candidate solutions is evaluated. Based on the evaluation results, feasible candidate solutions for optimization and coordination are obtained, and the optimization and coordination operation results are output.

[0052] Specifically, step 1 includes the following:

[0053] Step 1.1: Based on the existing transient process calculation model, calibrate the opening flow and output models of each level of power plant unit; the transient process calculation model is implemented using existing technology;

[0054] Step 1.2: Based on the allowable error α (1% in this embodiment, which can be set as needed), calculate the steady current of each power station, i.e., based on the single unit output P. i The corresponding single-machine flow rate Q within the tolerance range is obtained. i With respect to the opening degree y of the corresponding single unit i Based on these three values, construct the solution set matrix [P]. i Q i ,y i ];

[0055] Repeat steps 1.1 and 1.2, that is, establish the solution set matrix for each power station level one by one, until the solution set matrix of the multi-stage series power stations is obtained, which is the opening-flow-output model of the multi-stage series power stations. Obtain the opening-flow-output relationship of the units at each level of the power station based on the opening-flow-output model.

[0056] Specifically, step 2 includes the following:

[0057] The process of establishing the forward interpolation function involves converting the output of a single unit into a percentage output, and constructing forward interpolation functions from the percentage output to the flow rate of a single unit and from the percentage output to the unit's operating level. This step expands the discrete sample curves into a continuously solvable model, enabling power plant units at all levels to obtain corresponding flow rate and operating level values ​​under any target percentage output, thus providing a foundation for subsequent flow matching and collaborative optimization.

[0058] For each level of power plant unit, the interpolation results from output percentage to individual unit flow rate are sorted, deduplicated, and monotonicized to establish an inverse interpolation function from individual unit flow rate to output percentage. The interpolation result refers to the encrypted output flow rate combination obtained after interpolation using the forward interpolation function. Given a candidate common total flow rate, the individual unit flow rate can be determined by the number of operating motors in each level of power plant unit. Then, the individual unit output percentage of each level of power plant unit is obtained using the inverse interpolation function, and the corresponding individual unit flow rate and unit operating degree are further obtained using the forward interpolation function. Through the combined forward and inverse interpolation mechanism, a collaborative solution process of "forwardly calculating the output percentage from the individual unit flow rate and then inversely calculating the unit operating degree from the output percentage" is realized in multi-level series power plants. This is the key to achieving flow matching operation of multi-level power plants in this embodiment of the invention.

[0059] Specifically, step 3 includes the following:

[0060] When the target total output percentage is lower than a preset threshold, all levels of power plants are allowed to operate with a reduced number of units simultaneously; when the target total output percentage is not lower than the preset threshold, all levels of power plants operate at the nominally available number of units. This strategy can minimize unnecessary shutdowns while meeting regulation requirements, ensuring stable unit operation and continuous regulation. Here, "nominal available" refers to all normally operating units participating in operation, and unit shutdowns are not considered when the target total output is not lower than the threshold. The total rated output of a multi-stage series power plant is the sum of the initially set rated outputs of each unit, and the rated output is a fixed value.

[0061] The target total output and given allowable error of a multi-stage series power plant are expressed as follows:

[0062] (1)

[0063] in, Contribute all efforts to the goal. To allow for a lower limit on total output, To allow for a maximum total output, For a given tolerance, i.e., the target total output range (from... to (the scope).

[0064] For multi-stage series power plants, the total flow rate through each stage should be consistent. The total flow rate refers to the total flow rate of a single stage power plant. Let the total flow rate of the multi-stage series power plants be Q, then the flow rate of each stage unit... The calculation is as follows:

[0065] (2)

[0066] Where, N i Indicates the number of operating units. This indicates the nominal number of available generating units, i.e., the number of generating units that are not shut down.

[0067] Based on the inverse interpolation function between unit operating degree, single unit flow rate, and single unit output, the corresponding output percentage can be determined from the single unit flow rate. :

[0068] (3)

[0069] in, Represents the inverse interpolation function. Indicates the power station level.

[0070] The single unit output of each power station unit is as follows:

[0071] (4)

[0072] Among them, P i,r Indicates the rated output of power plant units at each level. Indicates the rated value.

[0073] Taking a three-stage series power station as an example, the total output of a multi-stage series power station can be expressed as follows:

[0074] (5)

[0075] in, , , These represent the number of operating generating units at each level of the power station. , , These represent the individual unit output of each level of power plant unit.

[0076] The total output is obtained based on the output of a single unit, and the difference between the total output and the target total output is the total output error.

[0077] Based on the unit operating characteristics, the power output percentage of each level of power plant unit must meet the following conditions:

[0078] (6)

[0079] Considering hydraulic calculation and control errors, the total flow rate of each power station is allowed to be slightly different within a certain tolerance range. Let the flow rate tolerance coefficient be β (1‰ is selected in this embodiment of the invention), then the following must be satisfied:

[0080] (7)

[0081] The total rated output of multi-stage series power plants ( Based on this, define the target output percentage. for:

[0082] (8)

[0083] when The number of power plants in operation at each level is allowed to be between 1 and N. nom The frequency may vary, but the settings should be optimized to minimize the number of downtime units.

[0084] Specifically, step 4 includes the following:

[0085] By enumerating feasible intervals for the common total flow under different combinations of unit numbers, and scanning and searching for the common total flow within these intervals, multiple candidate common total flows are obtained. For each candidate common total flow, the flow rate of each unit at each power station level is calculated, and the output percentage of each unit at each level is obtained using an inverse interpolation function. Then, the corresponding unit flow rate, unit operation, and unit output are obtained using a forward interpolation function. Based on the unit flow rate, unit operation, and unit output, the total flow rate of each power station level is obtained. The deviation between the total flow rates of each power station level is used to determine whether the constraints of the series power station system are met. Only candidate operating conditions that simultaneously satisfy the flow matching constraint, output range constraint, and operating range constraint are retained as feasible candidate solutions. Among them, the flow matching constraint can be selected as a deviation of 1‰, the output range constraint is the target total output range, and the operating range constraint is the setting to minimize downtime; the candidate operating condition is the engineering expression of the candidate solution, and the candidate solution is the mathematical expression of the candidate operating condition. Thus, this embodiment of the invention can screen out candidate operating points that simultaneously satisfy flow uniformity and output achievability in a multi-level series structure.

[0086] The efficiency of each power station unit is calculated based on its characteristic curves. First, the characteristic relationships of unit speed, unit flow rate, and unit torque are extracted at the corresponding operating degree of each power station unit. Then, combined with the actual operating speed, runner diameter, and head of the unit, the unit speed and unit flow rate corresponding to the actual operating conditions are calculated. The predicted values ​​of unit flow rate and unit torque under the current operating conditions are determined through two-stage interpolation. Next, the actual torque is recovered from the unit torque, and the mechanical power is obtained by combining it with the angular velocity. Simultaneously, the hydraulic power is obtained from the flow rate, head, water density, and gravitational acceleration, thus yielding the efficiency of each power station unit. Finally, the overall efficiency of the multi-stage series power station is obtained by the ratio of the sum of the mechanical power of each power station unit to the sum of the hydraulic power (i.e., the unit efficiency).

[0087] For the i-th level unit (i=1,2,3), its single-unit flow rate Q is known. i Water head H i Rotor diameter D i Rotational speed n i Convert unit flow rate and unit speed:

[0088] (9)

[0089] In this context, the parameter subscript indicates the unit value.

[0090] The unit characteristic curve can be expressed as a two-dimensional mapping relationship between unit torque and unit flow rate and unit speed, that is:

[0091] (10)

[0092] Based on the conversion relationship between unit torque and actual torque, the actual output torque of the i-th level unit is... for:

[0093] (11)

[0094] in, denoted by density, g represents gravitational acceleration.

[0095] Mechanical output power of the i-th stage unit and hydraulic input power They are respectively:

[0096] (12)

[0097] Where the subscript m represents mechanical power and h represents hydraulic input power, The unit's angular velocity. Single-stage unit efficiency. It can be represented as:

[0098] (13)

[0099] When the number of units in operation at level i is N i At that time, the total efficiency of the multi-stage series power plant is obtained based on the unit efficiency. Defined as:

[0100] (14)

[0101] Step 5: Construct an optimization problem with the dual objectives of minimizing the total output error and maximizing the overall efficiency of the multi-stage series power plants, evaluate the Pareto solution set obtained based on feasible candidate solutions, obtain feasible candidate solutions for optimization and coordination based on the evaluation results, and output the optimization and coordination operation results.

[0102] The process of obtaining the Pareto solution set includes: first, prioritizing candidate solutions that satisfy the target total output range from all feasible candidate solutions; if a candidate solution that satisfies the target total output range exists, it is directly included in the Pareto solution set; if no candidate solution satisfies the target total output range exists, all candidate solutions are retained for subsequent evaluation. Then, among the retained candidate solutions, a second selection is made based on the principle of minimizing the number of units shut down, and the selected candidate solutions are used as the Pareto solution set to reduce the impact of shutdown actions on the operational stability and regulation response continuity of multi-stage series power plants.

[0103] Based on this, an optimization problem is constructed with the dual objectives of minimizing total output error and maximizing the overall efficiency of multi-stage series power plants. A normalized weighted evaluation method is used to comprehensively evaluate the Pareto solution set. Specifically, firstly, the different objective indicators of each candidate solution in the Pareto solution set are dimensionless, transforming the total output error into a cost-type indicator and the system efficiency into a benefit-type indicator, mapping them all to the [0,1] interval, thereby eliminating the influence of dimensional differences; then, the weights of each objective are determined according to engineering preferences; each candidate solution is scored by a weighted summation method to obtain a unified comprehensive evaluation value; finally, the solution with the best comprehensive score is selected as the optimal Pareto solution in a compromise sense, thus determining the final optimal coordinated operation scheme. Thus, this invention realizes the optimization mechanism of "electricity-based water supply," "flow matching," and "efficiency optimization."

[0104] Step 6: Based on the evaluation results, obtain the optimal collaborative operation scheme and output the optimized collaborative operation results. The collaborative operation results include: the number of units in operation at each level of power station, the total common flow, the flow rate of each unit at each level of power station, the operating level of each unit at each level of power station, the output of each unit at each level of power station, the total output of each level of power station, the efficiency of each unit at each level of power station, the overall efficiency of the multi-stage series power stations, and the target total output error. This output not only directly reflects the operating status of each level of power station under optimal conditions but also provides clear action instructions for power station scheduling and control execution.

[0105] Specifically, this embodiment of the invention uses a multi-stage series power station as a basis for numerical simulation research. Figure 2 This is a schematic diagram of the layout of a multi-stage series power station in an embodiment of the present invention. The power station consists of four parts: an upstream reservoir, three water conveyance systems with two turbines in each tunnel, a regulating reservoir, and a downstream reservoir. Based on Figure 2 Based on the corresponding engineering conditions, a multi-stage series power station was modeled, and numerical simulation calculations were performed to verify the operating conditions. The steps are as follows:

[0106] Step 1: Establish a multi-stage series power station, which can be named Level 1, Level 2, and Level 3 power stations according to its elevation, and determine the opening, flow rate, and power output relationship of the multi-stage series power station.

[0107] Step 2: Establish a flow matching interpolation model. Based on the unit opening flow-output relationship obtained in Step 1, establish the forward interpolation function and the inverse interpolation function between the single unit flow and output percentage of each power station unit.

[0108] Step 3: Given the change in total output, the overall unit output is reduced from 100% to 90%, confirming that the change in total output is 10%. Based on the target total output and the allowable error of 1%, determine the target total output range.

[0109] Step 4: Search for the common total flow that satisfies the series flow consistency constraint under different combinations of the number of units. It is determined that a shutdown is necessary to meet the flow matching requirements. Therefore, a shutdown trial calculation is carried out to finally confirm the solution set under the flow matching and obtain the effective solution to form a solution set matrix.

[0110] Step 5: Optimize the strategy with the total output error and the overall efficiency of the multi-stage series power plant as objectives, and evaluate the Pareto solution set; the expression for multi-objective optimization is:

[0111] (15)

[0112] Step 6: Obtain the optimal collaborative operation scheme and output the results.

[0113] Specifically, by implementing load reduction conditions, the overall output of the multi-stage series power station is reduced from rated capacity to 80%. The optimization process is illustrated below. Figure 3 As shown, the solution set after flow matching is represented by solid dots. Subsequently, optimization based on multiple objectives yields a solution set represented by hollow dots. The optimal solution is selected through evaluation, represented by star dots. In the traditional power allocation mode, the power of each level of power plant unit is set to 80%. The flow matching mode allocates the power of the first, second, and third level power plants to 86.8%, 78.9%, and 74.4%, respectively. The surge tank water levels of the third-level power plant under the power allocation mode and the flow matching mode are shown below. Figure 4 As shown, the water levels in the two regulating tanks are as follows: Figure 5 As shown in the comparison, the regulating pool water level achieved good stability under the flow matching mode. Although there are certain differences in flow and output among different units, they are sufficient to meet the actual engineering requirements. The above analysis illustrates the effectiveness of the embodiments of the present invention and its practicality in ensuring the long-term stable operation of multi-stage series power plants. The method proposed in this invention is a fundamental method that can adjust the unit operation according to the required output while ensuring flow matching of multi-stage series power plants, achieving optimization under the trade-off between unit efficiency and output error.

[0114] The implementation of the various embodiments of the present invention is based on programmed processing by a device with processor functionality. Therefore, in practical engineering, the technical solutions and functions of the various embodiments of the present invention are encapsulated into various modules. Based on this reality, and building upon the above embodiments, the embodiments of the present invention provide a multi-stage series power plant optimization and collaborative operation system based on flow matching. This system is used to execute a multi-stage series power plant optimization and collaborative operation method based on flow matching from the above method embodiments.

[0115] The system includes: a first processing module for establishing an operation, flow rate, and output model for multi-stage series power plants, and obtaining the operation, flow rate, and output relationship of each stage of the power plant units; a second processing module for establishing a flow matching interpolation model: based on the operation, flow rate, and output relationship of each stage of the power plant units, establishing forward and inverse interpolation functions between unit operation, single-unit flow rate, and single-unit output; a third processing module for determining the target total output based on the initial total output and changes in total output, determining the target total output range based on the allowable error, and then determining the combination of the number of working units in each stage of the power plant based on the proportion of the target total output to the total rated output of the multi-stage series power plants; and a fourth processing module for... The fifth processing module searches for candidate common total flow ranges that satisfy the series flow consistency constraint under the feasible interval of the common total flow range of the same number of working units, and calculates the unit operation, single unit flow, single unit output and unit efficiency of each level of power station; the sixth processing module is used to obtain the total output based on the single unit output, obtain the total output error based on the target total output, and obtain the overall efficiency of the multi-stage series power station based on the unit efficiency; the seventh processing module is used to construct an optimization problem with the dual objectives of minimizing the total output error and maximizing the overall efficiency of the multi-stage series power station, and evaluate the Pareto solution set; the eighth processing module is used to obtain the optimal coordinated operation scheme based on the evaluation results and output the optimized coordinated operation results.

[0116] The multi-stage series power plant optimization and collaborative operation system based on flow matching provided in this invention addresses the lack of a collaborative operation framework in multi-energy complementary scenarios in existing technologies, as well as the problem of how to optimize scheduling strategies and reduce water and energy curtailment while ensuring the safe, stable, and coordinated operation of multi-stage units. It provides a method for optimizing and collaboratively operating multi-stage series power plants based on flow matching, constructing a collaborative operation model for multi-stage series power plants including operation, flow, and output models for each level of power plant and a flow matching interpolation model. It provides the total output variation range of the multi-stage series power plants, and, combined with the continuous flow constraints between upper and lower levels, determines the combination of operable units and the feasible common flow interval for each level of power plant. Through inverse interpolation, it solves for the corresponding output and operation of units at different flow rates, obtaining a solution set matrix that meets the requirements. Under the conditions of satisfying flow matching and output constraints, it establishes a collaborative optimization problem with the objectives of minimizing the total output deviation and maximizing the overall efficiency of the multi-stage series power plants, screening and selecting candidate operation schemes. Finally, it obtains the optimal unit configuration, single-unit load allocation, operation level, and optimal efficiency of the multi-stage series power plants for each level of power plant.

[0117] Finally, it should be noted that the above specific embodiments are merely representative examples of the present invention. Obviously, the present invention is not limited to the above specific embodiments and many variations are possible. Any simple modifications, equivalent changes, and alterations made to the above specific embodiments based on the technical essence of the present invention should be considered within the protection scope of the present invention.

Claims

1. A method for optimized and coordinated operation of multi-stage series power plants based on flow matching, characterized in that, include: Establish an operating flow-output model for a multi-stage series power plant to obtain the operating flow-output relationship between the units at each stage of the power plant. Establish a flow matching interpolation model: Based on the relationship between the operating rate, flow rate, and output of power plants at all levels, establish forward and inverse interpolation functions between unit operating rate, single-unit flow rate, and single-unit output, including: Convert the output of a single unit into a percentage of output, and construct positive interpolation functions from the percentage of output to the flow rate of a single unit and from the percentage of output to the unit's operating degree. Based on the interpolation results from output percentage to single-unit flow rate, sorting, deduplication, and monotonicity processing are performed to establish an inverse interpolation function from single-unit flow rate to output percentage; where the interpolation result refers to the encrypted output flow rate combination obtained after interpolation processing through the forward interpolation function; Based on the given target total output, the target total output range is determined by combining the preset allowable error. Then, based on the proportion of the target total output to the total rated output of the multi-stage series power stations, the number of working units of each power station is determined. Based on the feasible range of common total flow under different combinations of the number of operating units, the total flow of each level of power station is determined by combining the flow matching interpolation model, and candidate solutions that satisfy the constraints of the series power station system are selected as feasible candidate solutions based on the deviation between the total flow of each level of power station; the feasible candidate solutions include the unit operation, single unit flow, single unit output and unit efficiency of each level of power station units. The total output is obtained based on the output of a single unit, the total output error is obtained by combining the target total output, and the overall efficiency of the multi-stage series power station is obtained based on the unit efficiency. An optimization problem is constructed with the dual objectives of minimizing the total output error and maximizing the overall efficiency of the multi-stage series power plants. The Pareto solution set obtained based on feasible candidate solutions is evaluated, and feasible candidate solutions for optimization and coordination are obtained based on the evaluation results. The optimized and coordinated operation results are then output.

2. The method for optimized and coordinated operation of multi-stage series power plants based on flow matching according to claim 1, characterized in that, The process of establishing the flow rate output model includes: Based on the transient process calculation model, the opening flow and output models of power plant units at all levels are calibrated; Based on the required output of each power station, the flow rate and opening degree within the tolerance range are obtained, and a solution set matrix is ​​established. The solution set matrix is ​​established for each power station in turn until the solution set matrix of the multi-stage series power stations is obtained.

3. The method for optimized and coordinated operation of multi-stage series power plants based on flow matching according to claim 1, characterized in that, Based on the proportion of the target total output to the total rated output of the multi-stage series power plants, the number of operating units in each stage of the power plant is determined, including: When the target total output is lower than the total rated output of the multi-stage series power stations, the power stations at each stage are allowed to operate at reduced capacity simultaneously. When the target total output accounts for no less than a preset threshold of the total rated output of the multi-stage series power stations, each level of power station operates according to the nominal number of units available; the nominal number of units available refers to the participation of all normally operating units.

4. The method for optimized and coordinated operation of multi-stage series power plants based on flow matching according to claim 1, characterized in that, The calculation process for the unit efficiency is as follows: Based on the current operating level of each power plant unit, extract the characteristic relationships of unit speed, unit flow rate, and unit torque at the corresponding operating level; Based on the actual operating speed, runner diameter and head of the unit, the unit speed and unit flow rate under the actual operating conditions are calculated, and the predicted values ​​of unit flow rate and unit torque under the current operating conditions are determined by two-stage interpolation. The actual torque is recovered from the unit torque, and the mechanical power is obtained by combining the angular velocity. At the same time, the hydraulic power is obtained by the flow rate, head, water density and gravitational acceleration, and the efficiency of each level of power station unit is obtained.

5. The method for optimized and coordinated operation of multi-stage series power plants based on flow matching according to claim 1, characterized in that, The process of obtaining the Pareto solution set includes: Select candidate solutions from the feasible candidate solutions that satisfy the target total output range: If there exists a candidate solution that satisfies the target total output range, it is directly used as the Pareto solution set.

6. The method for optimized and coordinated operation of multi-stage series power plants based on flow matching according to claim 5, characterized in that, If there is no candidate solution that satisfies the target total output range, then all candidate solutions are retained; among all retained candidate solutions, the candidate solution with the fewest shutdowns is selected as the Pareto solution set.

7. The method for optimized and coordinated operation of multi-stage series power plants based on flow matching according to claim 1, characterized in that, The constraints of the series power plant system include flow matching constraints, output range constraints, and operating range constraints.

8. The method for optimized and coordinated operation of multi-stage series power plants based on flow matching according to claim 1, characterized in that, The optimized and coordinated operation results include the number of units put into operation at each level of power station, the total common flow, the flow of a single unit at each level of power station, the operating degree of a unit at each level of power station, the output of a single unit at each level of power station, the total output of each level of power station, the efficiency of a unit at each level of power station, the overall efficiency of a multi-stage series power station, and the target total output error.

9. A multi-stage series power plant optimized collaborative operation system based on flow matching, characterized in that, A method for optimizing and coordinating the operation of multi-stage series power plants based on flow matching, as described in any one of claims 1-8, includes: The first processing module is used to establish an operating flow and output model for a multi-stage series power station and obtain the operating flow and output relationship of each stage of the power station unit. The second processing module is used to establish a flow matching interpolation model: based on the relationship between the opening, flow and output of the power plants at all levels, it establishes the forward interpolation function and the inverse interpolation function between the opening, flow and output of the unit and the single unit. The third processing module is used to determine the target total output range based on the given target total output and the allowable error, and then determine the number of working units of each power station according to the proportion of the target total output to the total fixed output of the multi-stage series power station. The fourth processing module is used to determine the total flow of each power station based on the common total flow feasible interval under different combinations of the number of operating units, combined with the flow matching interpolation model, and select candidate solutions that satisfy the constraints of the series power station system as feasible candidate solutions based on the deviation between the total flow of each power station. The feasible candidate solutions include the unit operation, single unit flow, single unit output and unit efficiency of each power station unit. The fifth processing module is used to obtain the total output based on the output of a single unit, to obtain the total output error by combining the target total output, and to obtain the overall efficiency of the multi-stage series power station based on the unit efficiency. The sixth processing module is used to construct an optimization problem with the dual objectives of minimizing the total output error and maximizing the overall efficiency of the multi-stage series power station, evaluate the Pareto solution set obtained based on feasible candidate solutions, obtain feasible candidate solutions for optimization and coordination based on the evaluation results, and output the optimization and coordination operation results.

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