A hydropower station real-time load fine adjustment method

Abstract

The application discloses a hydropower station real-time load fine adjustment method, relates to the technical field of hydropower station dispatching operation, and comprises an adjustment mode of "firstly determining a start-up combination, and then optimizing load distribution", first constructs a unit operation state comprehensive evaluation model considering multiple factors such as a maintenance plan, start-stop time constraints, cumulative generating hours, water consumption coefficients and the like, and scientifically determines a start-up sequence; then, a load optimization distribution model is established by comprehensively considering the targets of reducing power station power generation water consumption and avoiding unit frequent crossing of a vibration area, so that the fine adjustment of real-time load is realized. By adopting the above method, the hydropower station can quickly respond to the load fluctuation demand of a power grid, simultaneously effectively reduces the start-stop of units and the number of times of crossing the vibration area, provides an effective solution for intelligent operation of the hydropower station under the background of high proportion of new energy access to the power system, and is suitable for the scene of frequent load fluctuation under the background of high penetration rate of new energy.

Description

Technical Field

[0001] This invention relates to the field of hydropower station dispatching and operation technology, and in particular to a method for real-time refined adjustment of hydropower station load. Background Technology

[0002] With the large-scale integration of new energy sources into the power grid, the penetration rate of intermittent energy sources such as wind power and photovoltaics is constantly increasing, leading to a significant increase in the frequency and amplitude of power system load fluctuations, and making the demand for power grid peak shaving and frequency regulation increasingly urgent. As a key adjustable power source in the power system, hydropower stations are undertaking increasingly frequent load adjustment tasks, which also places higher demands on their flexibility and regulation capabilities.

[0003] However, the current load adjustment strategy for hydropower stations has obvious shortcomings: on the one hand, it lacks detailed consideration of the operating status of the units, and cannot scientifically assess and coordinate the operating differences between the units, resulting in too many unit start-ups and shutdowns; on the other hand, it mainly relies on the experience judgment of dispatchers, lacking scientific and quantitative decision-making basis, resulting in a series of problems such as frequent crossing of vibration zones, increased equipment wear and tear, and decreased water energy utilization efficiency.

[0004] To this end, this invention establishes a comprehensive evaluation model of unit operation status that considers multiple factors such as maintenance plans, start-up and shutdown time constraints, cumulative power generation hours, and water consumption coefficients. This model scientifically determines the start-up sequence and introduces a vibration-damping water consumption coefficient to transform the multi-objective optimization problem into a single-objective solution. This enables the scientific and precise adjustment of hydropower station load, effectively reducing start-up and shutdown operations and vibration-damping frequency while meeting the requirements for rapid response. This significantly improves the overall operating efficiency, equipment lifespan, and economic benefits of the hydropower station. Summary of the Invention

[0005] The purpose of this invention is to provide a method for real-time refined load adjustment of hydropower stations, which can comprehensively consider the operating status of the units, reduce the number of unit start-ups and shutdowns, reduce vibration loss, and realize the efficient utilization of water resources in hydropower stations.

[0006] To achieve the above objectives, the present invention provides a method for real-time refined load adjustment of a hydropower station, comprising the following steps:

[0007] S1. Based on the unit's maintenance plan, start-up and shutdown time, output ramp-up constraints, and start-up and shutdown plan, determine the start-up and shutdown status of all units in the hydropower station to identify the units that need to be started and shut down.

[0008] S2. Based on the cumulative power generation hours, water consumption coefficient, water consumption during startup and water consumption during shutdown of the unit, establish a comprehensive evaluation model of the unit's operating status, determine the unit startup sequence, and determine the startup combination according to the power station load adjustment task requirements.

[0009] S3. Under a given start-up combination, establish a load optimization allocation model based on the hydropower station's power generation water consumption flow and the number of times the unit crosses the vibration zone to meet the needs of real-time load adjustment.

[0010] Furthermore, the rules for determining the start / stop status in S1 are as follows:

[0011] When the unit is included in the maintenance schedule, it must be shut down;

[0012] If the unit is not included in the maintenance plan, is currently in a shutdown state, and does not meet the minimum downtime constraint, or meets the minimum downtime constraint but the start-up / shutdown plan for the next period is shutdown, it must remain shut down;

[0013] If the unit is not included in the maintenance plan, is currently in the operating state, and does not meet the minimum operating time constraint, or meets the minimum operating time constraint but the start-up and shutdown plan for the next period is to start the unit, it must remain in the operating state.

[0014] In all other cases, it is a unit that can be turned off / on.

[0015] Furthermore, the comprehensive evaluation model for unit operating status in S2 is as follows:

[0016] E s =α[w1 w2 w3 w4]×[e1 e2 e3 e4] T ;

[0017] In the formula, E s The evaluation values ​​for the unit's operating status are as follows: e1, e2, e3, and e4 are the normalized values ​​of the unit's cumulative power generation hours, water consumption coefficient, water consumption during unit startup, and water consumption during unit shutdown, respectively; w1, w2, w3, and w4 are the corresponding weighting coefficients; and α is the reduction coefficient. The reduction coefficient is used to ensure that the startup priority of units that can be started / stopped is lower than that of units that are already in operation. Therefore, the evaluation values ​​should be reduced by a coefficient to ensure that the value is less than 1.

[0018] Furthermore, the unit start-up sequence is based on the unit operating status evaluation value E. s Confirmed, E s The higher the value, the higher the boot priority. s The smaller the value, the lower the boot priority.

[0019] Furthermore, the steps in S2 to determine the power generation combination include: gradually increasing the number of units from high to low according to the unit start-up sequence, and updating the feasible output range of the power station until the needs of the power station load adjustment task are met, thereby determining the power station's power generation combination.

[0020] Furthermore, the load optimization allocation model in S3 takes minimizing the water consumption for power generation at the hydropower station and minimizing the number of times the unit passes through the vibration zone as the optimization objectives, and solves it using a double-nested dynamic programming algorithm.

[0021] Furthermore, the load optimization allocation model introduces a water consumption flow coefficient for crossing the vibration zone and includes unit vibration as a penalty term, incorporating it into the total water consumption along with the power plant's power generation water consumption. This transforms the bi-objective optimization problem of minimizing power generation water consumption and minimizing the number of vibration crossings into a single objective, expressed as:

[0022]

[0023] In the formula, f(P) t,i ,g t,i ) represents the i-th level power station in time period t within the interval combination g. t,i Below, bearing the load P t,i The optimal water flow rate for power generation; Let cross(g) be the vibration damping flow coefficient of the i-th stage power station; t-1,i ,g t,i ) represents the interval combination number of the i-th level power station in time period t, determined by g. t-1,i Adjust to g t,i The total number of times the vibration zone was crossed;

[0024] Among them, the interval combination is defined as the set formed by the arrangement and combination of all feasible intervals of the operating units.

[0025] Furthermore, the double-nested dynamic programming algorithm includes:

[0026] First, using the load allocated to each unit as the decision variable, a dynamic programming algorithm is adopted, with the minimum water consumption as the optimization objective, to search for the optimal load allocation scheme of each unit under a fixed interval combination.

[0027] Then, using the interval combination as the decision variable, the total water consumption target is the sum of the power generation water consumption after load adjustment and the vibration water consumption before and after adjustment. The dynamic programming algorithm is used to search for the optimal interval combination and the corresponding load adjustment scheme according to the goal of minimizing the total water consumption.

[0028] Furthermore, the calculation steps for the number of times the unit crosses the vibration zone in S3 are as follows:

[0029]

[0030] Among them, cross(g) t-1 ,g t The combination number of the interval t for the time period is given by g. t-1 Adjust to g t The number of times the vibration zone is crossed; et,j e t-1,j For the interval combination number g t g t-1 The feasible interval number for the j-th generating unit can be calculated as follows:

[0031]

[0032] Among them, y j The intermediate number is calculated from the nth unit to the 1st unit, with the initial y... n The interval combination number; q j c is the number of operable intervals for the j-th unit; j Let be the feasible interval number of the j-th unit; floor(*) is the floor function, and mod(*) is the modulo function.

[0033] Therefore, the present invention employs the above-mentioned method for real-time refined adjustment of hydropower station load, which has the following technical effects:

[0034] (1) Traditional hydropower station load adjustment strategies lack refined consideration at the unit level. This invention establishes a comprehensive evaluation model of unit operation status, which comprehensively considers factors such as unit maintenance plans, start-up and shutdown time constraints, cumulative power generation hours, and water consumption coefficients, and scientifically determines the start-up and shutdown sequence of the units, effectively reducing the number of start-up and shutdown times, reducing equipment wear and energy consumption, extending the service life of the units, and significantly improving the overall operating efficiency of the hydropower station.

[0035] (2) Conventional hydropower station load adjustment mainly relies on the experience of dispatchers and lacks a systematic and scientific decision-making method. This invention adopts the method of "first determining the generator combination and then adjusting the load", which transforms the complex problem of hydropower station load adjustment into sub-problems that can be solved step by step. First, the optimal generator combination is determined based on the unit status evaluation model. Then, a load optimization allocation model is established, which overcomes the limitations of experience-based decision-making and greatly improves the scientificity and economy of dispatching.

[0036] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0037] Figure 1 This is a flowchart of a method for real-time refined load adjustment in hydropower stations;

[0038] Figure 2 This is a flowchart illustrating the start-up and shutdown status determination in an embodiment of a method for real-time refined load adjustment of a hydropower station;

[0039] Figure 3This is a schematic diagram of the feasible interval of a unit in an embodiment of a real-time load fine adjustment method for a hydropower station, where (a) is the case where the lower limit of the feasible interval is greater than 0, and (b) is the case where the lower limit of the feasible interval is equal to 0.

[0040] Figure 4 This is a schematic diagram of interval combinations in an embodiment of a method for real-time refined load adjustment of a hydropower station;

[0041] Figure 5 This is a comparison diagram of the output process of each unit under two different adjustment modes (adjustment at 12:00 and adjustment at 8:00) and historical schemes in an embodiment of a real-time load fine adjustment method for hydropower stations. Among them, (a) is the historical scheduling scheme of Unit #1, (b) is the scheme after Unit #1 participates in the adjustment at 12:00, (c) is the scheme after Unit #1 participates in the adjustment at 8:00; (d) is the historical scheduling scheme of Unit #2, (e) is the scheme after Unit #2 participates in the adjustment at 12:00, (f) is the scheme after Unit #2 participates in the adjustment at 8:00; (g) is the historical scheduling scheme of Unit #3, (h) is the scheme after Unit #3 participates in the adjustment at 12:00, and (i) is the scheme after Unit #3 participates in the adjustment at 8:00. Detailed Implementation

[0042] The present invention will be explained in more detail through the following embodiments. The purpose of disclosing the present invention is to protect all changes and modifications within the scope of the present invention. The present invention is not limited to the following embodiments.

[0043] Example 1

[0044] like Figure 1 As shown, the present invention provides a method for real-time refined load adjustment of a hydropower station, comprising the following steps:

[0045] S1. Based on the unit's maintenance plan, start-up and shutdown time, output ramp-up constraints, and start-up and shutdown plan, determine the start-up and shutdown status of all units in the hydropower station to identify the units that need to be started and shut down.

[0046] If the unit is included in the maintenance schedule, it must be shut down. If the unit is not included in the maintenance schedule, is currently shut down, and does not meet the minimum downtime constraint, or meets the minimum downtime constraint but the next start-up / shutdown schedule is for shutdown, it must remain shut down. If the unit is not included in the maintenance schedule, is currently on, and does not meet the minimum start-up constraint, or meets the minimum start-up constraint but the next start-up / shutdown schedule is for start-up, it must remain on. In all other cases, it is considered a unit that can be shut down / started.

[0047] S2. An evaluation model for the unit's operating status is established based on the unit's cumulative generating hours, water consumption coefficient, start-up water consumption, and shutdown water consumption indicators. This model evaluates the operating status of the units that can be shut down / started in S1, thereby determining the unit start-up sequence. The unit operating status evaluation model is as follows:

[0048] E s =α[w1 w2 w3 w4]×[e1 e2 e3 e4] T ;

[0049] In the formula, E s E is the unit's operating status evaluation value. s The larger the value, the higher the priority of starting up; the smaller the value, the lower the priority of starting up. Since the magnitudes of different indicators are inconsistent, normalization processing is required. e1, e2, e3, and e4 are the normalized values ​​of the unit's cumulative power generation hours, unit water consumption coefficient, unit start-up water consumption, and unit shutdown water consumption. w1, w2, w3, and w4 are the corresponding weighting coefficients. α is a reduction coefficient. To ensure that the start-up priority of units that can be started / stopped is lower than that of units that are already in operation, the status evaluation value needs to be reduced by a coefficient to ensure that it is less than 1. In this embodiment, it is taken as 0.9.

[0050] S3. Based on the starting sequence calculated in S2, the units are gradually added from high to low, and the feasible range of the power station is updated until the requirements of the power station load adjustment task are met, thereby determining the starting combination of the power station.

[0051] S4. Under the starting combination determined in S3, the optimization objectives are to minimize the power plant's water consumption for power generation and the number of times the unit passes through the vibration zone. By introducing a water consumption coefficient for passing through the vibration zone and treating unit vibration as a penalty term, which is included in the total water consumption along with the power plant's water consumption for power generation, the dual-objective optimization problem of minimizing water consumption for power generation and minimizing the number of vibration passes is transformed into a single objective. The transformed objective function is as follows:

[0052]

[0053] In the formula, f(P) t,i ,g t,i ) represents the i-th level power station in time period t within the interval combination g. t,i Below, bearing the load P t,i The optimal water flow rate for power generation; Let cross(g) be the vibration damping flow coefficient of the i-th stage power station; t-1,i ,g t,i ) represents the interval combination number of the i-th level power station in time period t, determined by g. t-1,i Adjust to g t,i The total number of times the vibration zone was crossed.

[0054] The definition of interval combinations is as follows:

[0055] like Figure 3 As shown, the feasible output of the unit under complex constraints presents a multi-segment interval, with the initial feasible interval of unit j being... Subject to two vibration zones The constraints divide the feasible space into three segments. Furthermore, since no-load operation is permitted, zero-output operation under no-load conditions must be added to the original feasible space, forming the unit's feasible intervals. The number of operational intervals for the unit is called the number of feasible intervals. Figure 3 (a) The number of feasible intervals for the unit is 4, which are marked with 1, 2, 3, and 4. Figure 3 (b) The number of feasible intervals for each generating unit is 3, labeled 1, 2, and 3. The set of all possible combinations of feasible intervals for operating generating units is called an interval combination. The interval combination sequence is determined by arranging the feasible interval numbers from bottom to top, as follows: Figure 4 As shown. Let n be the number of generating units in operation at a power station under a certain unit combination, and q be the number of generating units in operation. j Let be the number of operable intervals for the j-th generating unit. Then, the total number of interval combinations under this unit combination is: Use [1,2,...,N] c [This is used to represent something].

[0056] The steps for calculating the number of times the vibration zone is crossed based on the interval combination are as follows:

[0057]

[0058] Among them, cross(g) t-1 ,g t ) represents the combination number of the time interval t by g t-1 Adjust to g t The number of times the vibration zone is crossed; e t,j e t-1,j For the interval combination number g t g t-1 The feasible interval number for the j-th generating unit can be calculated as follows:

[0059]

[0060] Among them, y j To calculate the intermediate number, starting from unit n and moving up to unit 1, the initial y... n For interval combination number; c j Let be the feasible interval number of the j-th unit; floor(*) is the floor function; mod(*) is the modulo function.

[0061] The model solution employs a double-layer nested dynamic programming algorithm: First, using the load allocated to each unit as the decision variable, the dynamic programming algorithm searches for the optimal load allocation scheme for each unit under a certain fixed interval combination, with the minimum water consumption as the optimization objective; then, using the interval combination as the decision variable, the dynamic programming algorithm searches for the optimal interval combination and the corresponding load adjustment scheme, with the sum of the power generation water consumption after load adjustment and the vibration-induced water consumption before and after adjustment as the total water consumption objective, and with the minimum total water consumption objective.

[0062] Example 2

[0063] This embodiment takes the Hongjiadu Hydropower Station in the Wujiang River Basin as the research object, and selects the period from 8:00 on February 2, 2018 to 7:00 on February 3, 2018 as the implementation period. Starting from 8:00 and 12:00 on February 2, 2018, respectively, the load adjustment is carried out on the input real-time fluctuating load using the method proposed in this invention, and the adjustment is compared with historical schemes to verify the effectiveness and rationality of the method of this invention.

[0064] Please see Figure 5 Under the historical scenario, the three generating units at Hongjiadu would operate in the vibration zone during certain periods. However, after introducing a refined load adjustment strategy, the units were able to avoid operating in the vibration zone, and the number of vibration cycles significantly decreased. Under the historical scenario, the units frequently experienced vibration cycles; Unit #1 experienced 28 vibration cycles during the implementation period, including 23 between 12:00 and 7:00. However, after implementing the refined load adjustment strategy at 12:00, the number of vibration cycles quickly dropped to 9. Similarly, the number of vibration cycles for Units #2 and #3 between 12:00 and 7:00 also decreased from 24 and 18 respectively to 7 and 10, showing good optimization results. The vibration optimization effect of the Hongjiadu units under the 8:00 adjustment mode was even more significant. During the implementation period, the number of vibration cycles for Units #1 to #3 decreased from 28, 32, and 23 to 2, 3, and 6 respectively. Regarding the number of unit start-ups and shutdowns, under the historical scheme, the Hongjiadu #1 unit started and shut down 4 times during the implementation period. However, after the load fine-tuning strategy, the number of start-ups and shutdowns was reduced to 1. Overall, the load adjustment method proposed in this invention takes into account both the safety and economy of unit operation, reducing the number of unit start-ups and shutdowns while avoiding frequent crossings of vibration zones.

[0065] Therefore, the present invention adopts the above-mentioned method for real-time load fine adjustment of hydropower stations, which realizes the scientific and precise adjustment of hydropower station load, can meet the requirements of rapid response, and effectively reduces start-up and shutdown operations and vibration cycles, significantly improving the overall operating efficiency, equipment life and economic benefits of hydropower stations.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for real-time refined load adjustment of a hydropower station, characterized in that, Includes the following steps: S1. Based on the unit's maintenance plan, start-up and shutdown time, output ramp-up constraints, and start-up and shutdown plan, determine the start-up and shutdown status of all units in the hydropower station to identify the units that need to be started and shut down. The rules for determining the start / stop status in S1 are as follows: When the unit is included in the maintenance schedule, it must be shut down; If the unit is not included in the maintenance plan, is currently in a shutdown state, and does not meet the minimum downtime constraint, or meets the minimum downtime constraint but the start-up / shutdown plan for the next period is shutdown, it must remain shut down; If the unit is not included in the maintenance plan, is currently in the operating state, and does not meet the minimum operating time constraint, or meets the minimum operating time constraint but the start-up and shutdown plan for the next period is to start the unit, it must remain in the operating state. In all other cases, it is a unit that can be turned off / on. S2. Based on the cumulative power generation hours, water consumption coefficient, water consumption during startup and water consumption during shutdown of the unit, establish a comprehensive evaluation model of the unit's operating status, determine the unit startup sequence, and determine the startup combination according to the power station load adjustment task requirements. The comprehensive evaluation model for unit operating status in S2 is as follows: ； In the formula, This is the evaluation value for the unit's operating status; , , , These are the normalized values ​​of the unit's cumulative power generation hours, unit water consumption coefficient, unit water consumption during startup, and unit water consumption during shutdown, respectively. , , , These are the corresponding weighting coefficients; The reduction factor is used to ensure that the start-up priority of the start-up unit is lower than that of the start-up unit. The status evaluation value should be reduced by the factor to ensure that it is less than 1. The unit start-up sequence is based on the unit operating status evaluation value. Sure, The higher the value, the higher the boot priority. The smaller the value, the lower the boot priority; S3. Under a given start-up combination, based on the hydropower station's power generation water consumption and the number of times the unit passes through the vibration zone, establish a load optimization allocation model to meet the needs of real-time load adjustment. The load optimization allocation model in S3 aims to minimize the water consumption for power generation at the hydropower station and the number of times the generating units pass through the vibration zone. It is solved using a double-nested dynamic programming algorithm.

2. The method for real-time refined load adjustment of a hydropower station according to claim 1, characterized in that, The steps for determining the start-up combination in S2 include: gradually increasing the number of generating units from high to low according to the start-up sequence, and updating the feasible range of the power station until the needs of the power station load adjustment task are met, thereby determining the start-up combination of the power station.

3. The method for real-time refined load adjustment of a hydropower station according to claim 1, characterized in that, The load optimization allocation model introduces a water consumption flow coefficient for crossing the vibration zone and incorporates unit vibration as a penalty term, including it in the total water consumption flow along with the power plant's power generation water consumption. This transforms the bi-objective optimization problem of minimizing power generation water consumption and minimizing the number of vibration crossings into a single objective, expressed as: ； In the formula, For time period No. Level power station in interval combination Below, bear the load The optimal water flow rate for power generation; For the first The vibration damping flow coefficient of a hydroelectric power station; For time period No. The interval combination number of the level power station is determined by Adjusted to The total number of times the vibration zone was crossed; Among them, the interval combination is defined as the set formed by the arrangement and combination of all feasible intervals of the operating units.

4. The method for real-time refined load adjustment of a hydropower station according to claim 1, characterized in that, Nested dynamic programming algorithms include: First, using the load allocated to each unit as the decision variable, a dynamic programming algorithm is adopted, with the minimum water consumption as the optimization objective, to search for the optimal load allocation scheme of each unit under a fixed interval combination. Then, using the interval combination as the decision variable, the total water consumption target is the sum of the power generation water consumption after load adjustment and the vibration water consumption before and after adjustment. The dynamic programming algorithm is used to search for the optimal interval combination and the corresponding load adjustment scheme according to the goal of minimizing the total water consumption.

5. The method for real-time refined load adjustment of a hydropower station according to claim 1, characterized in that, The steps for calculating the number of times the unit crosses the vibration zone in S3 are as follows: ； in, For time period The interval combination number is determined by Adjust to And the number of times it crosses the vibration zone; , For interval combination number , The corresponding number The feasible range number for the unit is calculated as follows: ， ， ； in, For the intermediate number calculated, by the first... The calculation is up to the first unit, the initial... This is a combination of interval numbers; For the first Number of operational intervals for each generator unit; For the first Feasible range number for the Taiwanese unit; This is the floor function. It is the remainder function.

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