Power generation plan generation device and power generation plan creating method

Abstract

SOLUTION: To provide a power generation plan generation device 1 that includes a thermal power side generation plan generation unit 2 and a hydraulic power side generation plan generation unit 3, the thermal power side generation plan generation unit 2 including a first thermal power side optimization problem calculation unit 22 that solves an optimization problem and calculates a system λt derived from an optimal solution, and a second thermal power side optimization problem calculation unit 23 that solves the optimization problem in consideration of a hydraulic power side optimal solution calculated by the hydraulic power side power generation plan generation unit 3 and calculates the thermal power side optimal solution, the hydraulic power side power generation plan generation unit 3 including a hydraulic power side optimization problem calculation unit 32 that solves an optimization problem on a hydraulic power generation side so as to achieve maximum reduction in power generation cost of a thermal power plant in consideration of the system λt and calculates the hydraulic power side optimal solution.EFFECT: A power generation plan generation device and a power generation plan generation method capable of reducing calculation time can be obtained when a thermal power generation system and a hydraulic power generation system are loosely coupled.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] An embodiment of the present invention relates to a power generation plan generating device and a power generation plan generating method. [Background technology]

[0002] In order to optimize the operation of a power plant, the so-called Unit Commitment problem (hereafter referred to as the "UC problem") is solved. The UC problem is an optimization problem that examines how to start or stop each generator in the power plant in order to most economically meet the system demand and ensure supply reserve capacity.

[0003] In Japan in 2021, thermal power generation accounts for more than 60% of the domestic power generation mix. However, hydroelectric power generation is also used in conjunction with thermal power generation to reduce fuel costs. In addition, optimization problems are solved separately for both thermal power generation and hydroelectric power generation planning. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2002-233058 A Summary of the Invention [Problem to be solved by the invention]

[0005] It is desirable to derive an optimal solution by treating thermal and hydroelectric power generation as a single optimization problem, rather than solving thermal power generation planning and hydroelectric power generation planning as separate optimization problems. However, in many power companies, thermal power generation and hydroelectric power generation are operated as separate business flows. Therefore, in order to derive a single optimal solution for thermal and hydroelectric power generation as a whole, it is necessary to significantly review the surrounding operations and systems, which is not realistic. In addition, when solving thermal power generation and hydroelectric power generation as a single optimization problem, a combinatorial explosion occurs when the two are combined, meaning the amount of calculations becomes enormous and the calculation time increases.

[0006] Therefore, it is possible to loosely couple the thermal power generation and hydroelectric power generation systems and transmit the necessary data to each other. In other words, the thermal power generation and hydroelectric power generation solve the optimization problem by taking into account the data transmitted from the other party. However, since hydroelectric power generation is subject to constraints such as the amount of water stored and the weather, the actual situation is that the power generation plan is made by first calculating the output of hydroelectric power generation, subtracting the amount of hydroelectric power generation from the demand, and then creating a thermal power generation plan. Therefore, since the output of hydroelectric power generation is calculated without taking into account the state of thermal power generation, there is a risk that the power generation plan is not efficient. This is an area that has not been improved because it was considered unavoidable in the conventional supply and demand operation, but it has been attracting attention from the perspective of liberalization and profit improvement in recent years.

[0007] An embodiment of the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a power generation plan generation device and a power generation plan generation method that can create an efficient power generation plan when thermal power generation and hydroelectric power generation systems are loosely coupled. [Means for solving the problem]

[0008] The power generation plan generating device of this embodiment includes a thermal power generation plan generating unit that generates a power generation plan for a thermal power plant, and a hydroelectric power generation plan generating unit that generates a power generation plan for a hydroelectric power plant. The thermal power generation plan generating unit solves an optimization problem consisting of an objective function and a constraint equation, and generates a system λ derived from an optimal solution of the amount of power to be generated in thermal power generation according to a demand forecast. t A first thermal power side optimization problem calculation unit that calculates the system λ calculated by the first thermal power side optimization problem calculation unit t to the hydroelectric power generation plan generation unit; and a second thermal power side optimization problem calculation unit that solves the optimization problem by taking into account the hydroelectric power side optimal solution calculated by the hydroelectric power generation plan generation unit, and calculates a thermal power side optimal solution. The hydroelectric power generation plan generation unit is t and a hydropower-side optimization problem calculation unit that solves the optimization problem on the hydropower generation side, taking into account the above, so as to maximize the reduction in the power generation cost of the thermal power plant, and calculates a hydropower-side optimal solution, and a second transmission unit that transmits the hydropower-side optimal solution to the thermal power plant-side power generation plan generation unit.

[0009] In addition, the power generation plan generation method of the present embodiment is a power generation plan generation method including a thermal power generation plan generation unit that generates a power generation plan for a thermal power plant and a hydroelectric power generation plan generation unit that generates a power generation plan for a hydroelectric power plant, and solves an optimization problem consisting of an objective function and a constraint equation, and generates a system λ derived from an optimal solution of the amount of power generation to be generated at the thermal power plant according to the demand forecast. t A first thermal power side optimization problem calculation step for calculating the system λ calculated in the first thermal power side optimization problem calculation step t a first transmission step of transmitting the system λ to the hydroelectric power generation plan generating unit; t a hydropower-side optimization problem calculation step of solving an optimization problem on the hydropower side by taking into account the above-mentioned optimum solution and calculating a hydropower-side optimal solution, a second transmission step of transmitting the hydropower-side optimal solution calculated in the hydropower-side optimization problem calculation step to the thermal power-side power generation plan generation unit, and a second thermal power-side optimization problem calculation step of solving the optimization problem by taking into account the hydropower-side optimal solution transmitted in the second transmission step and calculating a thermal power-side optimal solution. [Brief description of the drawings]

[0010] [Figure 1] 1 is a block diagram showing an overall configuration of a power generation plan generating device 1 in a first embodiment. [Diagram 2] 2 is a flowchart according to the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] (First embodiment) A power generation plan generating device according to an embodiment will be described with reference to the drawings. Fig. 1 is a block diagram showing the overall configuration of a power generation plan generating device 1. The power generation plan generating device 1 generates power generation plans for a thermal power plant and a hydroelectric power plant. The power generation plan generating device 1 includes a calculation device such as a CPU and a storage device.

[0012] As shown in Fig. 1, the power generation plan generating device 1 includes a thermal power generation plan generating unit 2 and a hydroelectric power generation plan generating unit 3. The thermal power generation plan generating unit 2 and the hydroelectric power generation plan generating unit 3 are loosely coupled and are independent systems. That is, the thermal power generation plan generating unit 2 generates a power generation plan for the thermal power plant. The hydroelectric power generation plan generating unit 3 generates a power generation plan for the hydroelectric power plant.

[0013] The power generation plan generating device 1 first calculates a power demand forecast to be generated for thermal power generation and hydroelectric power generation. The thermal power generation plan generating unit 2 calculates a system λ , which is an optimal solution for the amount of power generation to be generated in thermal power generation, based on the power demand forecast. t The hydroelectric power generation plan generating unit 3 calculates the system λ t Then, the thermal power generation plan generating unit 2 solves the optimization problem again, taking into account the hydropower side optimal solution, calculates the thermal power side optimal solution, and generates an operation plan for the thermal power plant based on this thermal power side optimal solution.

[0014] The thermal power generation plan generating unit 2 includes a memory unit 21, a first thermal power optimization problem calculating unit 22, a second thermal power optimization problem calculating unit 23, a thermal power operation plan generating unit 24, a transmitting unit 25, and a receiving unit .

[0015] The storage unit 21 stores various functions and various data described later. The various data include data on power demand, data on each thermal power plant such as the start / stop status and power generation amount of each thermal power plant, data on the cost of fuel such as coal and natural gas, etc.

[0016] The first thermal power generation optimization problem calculation unit 22 solves the optimization problem so as to satisfy the power demand forecast, and calculates the system λ t In this case, the first thermal power optimization problem calculation unit 22 solves the optimization problem without considering the power generation amount or operation plan of the hydroelectric power plant. In other words, the optimal solution calculated by the first thermal power optimization problem calculation unit 22 is a provisional optimal solution, and the system λ derived from this provisional optimal solution t This does not mean that a final operation plan for thermal power generation will be created based on this.

[0017] The first thermal power optimization problem calculation unit 22 solves the optimization problem using the following formulated objective function and constraint equation, and calculates the system λ t Calculate the system λ t is the first derivative of the fuel cost function of each thermal power generator, and can be derived from the optimal solution obtained by solving the optimization problem. t The larger the value of , the greater the output and the higher the cost of the time period. The objective function is to minimize the total operation cost, which consists of fuel costs and startup costs, and is calculated using the following formula (1).

[0018]

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[0019] The constraint equation for the supply and demand balance is given by the following equation (2).

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[0020] The constraint equation for the output range of each thermal power generator is given by the following equation (3).

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[0021] The constraints on the consistency between the start / stop states, which are represented by binary variables, and the start timing / stop timing flags are given by the following equations (4) and (5).

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[0022] The constraints on the minimum start-up and shutdown times are given by the following equations (6) and (7).

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[0023] The constraint equation regarding the upper and lower limits of the output change rate of each generator is given by the following equation (8).

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[0024] The constraint equations for the up-down reserve capacity of each thermal power generator are given by the following equations (9) and (10), respectively.

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[0025] In the above formulas, i is the number of the thermal power generator, t is the time zone number, T is the set of time zone numbers, N th is the set of thermal generator numbers, c, b, and a are the quadratic terms in the fuel cost function [$ / (MW) 2 h], the linear term [$ / MWh], and the constant term [$ / h] are the coefficients, Δt is the discrete time span [h], r i is the limit of the power generation (maximum / minimum) of the rate of change of each thermal power generator [% / min],

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[0026] The second thermal power side optimization problem calculation unit 23 solves the optimization problem so as to satisfy the power demand forecast, and calculates the thermal power side optimal solution. The second thermal power side optimization problem calculation unit 23 calculates the thermal power side optimal solution using the objective function of the above formula (1) and the constraint formulas of formulas (2) to (10).

[0027] The second thermal power side optimization problem calculation unit 23 calculates the thermal power side optimal solution by taking into account the hydropower side optimal solution of the hydropower side described later. For example, the amount of power output by hydropower generation is subtracted from the power demand forecast to calculate the thermal power side optimal solution that becomes the operation plan for thermal power generation. In other words, the second thermal power side optimization problem calculation unit 23 differs from the first thermal power side optimization problem calculation unit 22 in that it solves the optimization problem by taking into account the hydropower side optimal solution.

[0028] The thermal power side operation plan generating unit 24 generates an operation plan for each thermal power plant based on the thermal power side optimal solution calculated by the second thermal power side optimization problem calculating unit 23. The operation plan for the thermal power plant includes the start or stop period of the thermal power plant in the power generation system, the amount of power generation per hour of each thermal power plant, etc., so as to minimize the cost.

[0029] The transmission unit 25 transmits the operation plan generated by the thermal power side operation plan generation unit 24 to each thermal power plant. The transmission unit 25 also transmits the system λ calculated by the first thermal power side optimization problem calculation unit 22. t to the hydroelectric power generation plan generating unit 3.

[0030] The receiving unit 26 receives the hydroelectric optimal solution calculated by the hydroelectric power generation plan generating unit 3 from the hydroelectric power generation plan generating unit 3. The receiving unit 26 also receives data related to each thermal power plant. The data received by the receiving unit 26 is stored in the memory unit 21.

[0031] The hydroelectric power generation plan generating unit 3 is a system λ tThe hydroelectric power generation plan generating unit 3 generates an operation plan for hydroelectric power generation while taking into account the above. The hydroelectric power generation plan generating unit 3 includes a storage unit 31, a hydroelectric side optimization problem calculating unit 32, a hydroelectric side operation plan generating unit 33, a transmitting unit 34, and a receiving unit 35.

[0032] The storage unit 31 stores objective functions and constraint equations for solving the minimization problem, and data related to each hydroelectric power plant. The data related to each hydroelectric power plant includes data on rivers, data on the relative positions of the hydroelectric power plants, data on the time it takes for water discharged from an upstream power plant to flow into a downstream power plant, data on the amount of water stored in the power plant, etc.

[0033] The hydroelectric power side optimization problem calculation unit 32 calculates the system λ calculated by the first thermal power side optimization problem calculation unit 23 so as to maximize the cost reduction in thermal power generation. t Specifically, the hydroelectric power generation optimization problem calculation unit 32 calculates the hydroelectric power generation optimal solution using the objective function shown in the following formula (11).

[0034]

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[0035] The hydroelectric power optimization problem calculation unit 32 considers constraint conditions such as boundary conditions of reservoir volume, maximum and minimum power generation, maximum and minimum reservoir volume, downstream flow rate, discharge volume of the hydroelectric power plant, and water arrival delay from the adjacent reservoir. These constraint conditions are given as commonly used constraint equations and are stored in the storage unit 31.

[0036] The hydroelectric power-side operation plan generating unit 33 generates an operation plan for each hydroelectric power plant based on the hydroelectric power-side optimal solution calculated by the hydroelectric power-side optimization problem calculating unit 32. The amount of power generation in each hydroelectric power plant is adjusted based on this operation plan.

[0037] The transmission unit 34 transmits to each hydroelectric power plant the operation plan generated by the hydroelectric side operation plan generation unit 33. The transmission unit 34 transmits the optimization calculated by the hydroelectric side optimization problem calculation unit 32 or the operation plan generated by the hydroelectric side operation plan generation unit 33 to the transmission / reception unit 25 of the thermal power side power generation plan generation unit 2.

[0038] The receiver 35 receives the system λ calculated by the thermal power generation plan generator 2. t The receiving unit 35 also receives various data of the hydroelectric power plant. The data received by the receiving unit 35 is stored in the storage unit 31.

[0039] (action) The operation of this embodiment will be described with reference to the drawings. Fig. 2 is a flowchart of this embodiment. First, the power generation plan generating device 1 predicts power demand and calculates a predicted value of power demand for each time unit, such as 30 minutes or 1 hour (step S01). Note that this predicted value does not necessarily have to be calculated by the power generation plan generating device 1, and may be calculated by an external device and received.

[0040] The first thermal power optimization problem calculation unit 22 of the thermal power generation plan generation unit 2 solves an optimization problem based on a predicted value of the power demand, and calculates the system λ t (Step S02). The system λ t The calculation does not take into account the amount of electricity generated by hydroelectric power plants.

[0041] The transmission unit 25 of the thermal power generation plan generation unit 2 is a system λ t The hydroelectric power generation plan generating unit 3 transmits the system λ t The hydraulic optimization problem calculation unit 32 receives the system λ received by the receiving unit 35 (step S04). tTaking this into consideration, a hydropower-side optimal solution for hydroelectric power generation is calculated (step S05). The hydropower-side optimization problem calculation unit 32 solves the optimization problem so as to maximize cost reduction in thermal power generation, and calculates the hydropower-side optimal solution. The hydropower-side operation plan generation unit 33 generates an operation plan for hydroelectric power generation based on this hydropower-side optimal solution. The transmission unit 34 transmits the operation plan to each hydroelectric power plant, and each hydroelectric power plant generates power based on the received operation plan.

[0042] The transmitting unit 34 also transmits the hydropower-side optimal solution calculated by the hydropower-side optimization problem calculation unit 32 to the thermal power generation plan generating unit 2 (step S06), and the receiving unit 26 receives the hydropower-side optimal solution (step S07). The second thermal power-side optimization problem calculation unit 23 calculates a thermal power-side optimal solution for thermal power generation in consideration of the hydropower-side optimal solution (step S08). That is, the second thermal power-side optimization problem calculation unit 23 calculates an optimal solution that minimizes the cost of thermal power generation while satisfying the power demand forecast by thermal power generation and hydropower generation in consideration of the power generation amount in hydropower generation.

[0043] Then, the thermal power side operation plan generating unit 24 generates a thermal power side operation plan based on the calculated thermal power side optimal solution, and the transmitting unit 25 transmits the operation plan to each thermal power plant. Each thermal power plant generates power based on the received operation plan.

[0044] (effect) As described above, the power generation plan generating device 1 of this embodiment first calculates the system λ t Then, the hydraulic optimization problem calculation unit 32 calculates the system λ t The second thermal power side optimization problem calculation unit 23 calculates the thermal power side optimal solution for thermal power generation by taking into account the hydropower side optimal solution and solving the optimization problem so as to maximize the cost reduction in thermal power generation.

[0045] Hydroelectric power generation is affected by weather conditions such as precipitation, and is subject to significant power generation constraints. For this reason, in the past, the amount of power generated by hydroelectric power generation was calculated without taking into account data on thermal power generation, such as the amount of power generated by thermal power generation, and then in the subsequent power generation plan, the amount of hydroelectric power generation was subtracted from demand to plan thermal power generation.

[0046] However, in this embodiment, the hydroelectric power generation plan generating unit 3 does not use the system λ calculated by the thermal power generation plan generating unit 2. t Taking these factors into account, the system calculates an optimal solution that minimizes the cost of thermal power generation. In other words, since the hydropower generation plan generating unit 3 knows the time periods when the cost of thermal power generation is high and low, it can know in which time periods the demand power should be efficiently covered by hydropower generation. This allows for efficient cost reduction.

[0047] Second embodiment A power generation plan generating device 1 according to the second embodiment will be described. The same configurations and functions are denoted by the same reference numerals, and detailed descriptions are omitted. Only different parts will be described. In the first embodiment, as shown in the above formula (1), the first thermal power side optimization problem calculation unit 22 calculates a system λ , which is an optimal solution as a nonlinear optimization problem. t In the second embodiment, the problem of the first thermal power side optimization problem calculation unit 22 is changed to a relatively simple problem.

[0048] Specifically, the objective function of the above formula (1) is replaced with the following formula (12), and the optimization problem is solved using the objective function as a linear approximation.

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[0049] In the above formula (12), f i is the linear coefficient of the linear approximation fuel cost function [$ / MWh], g i f denotes the constant term of the linear approximation fuel cost function. i and g i is derived by solving the following simultaneous equations (13) and (14).

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[0050] In this manner, in this embodiment, the first thermal power-side optimization problem calculation unit 22 solves the minimization problem as a mixed-integer linear programming problem (MILP) and calculates the system λ t As a result, compared to the first embodiment, the nonlinearity caused by the first thermal power side optimization problem calculation unit 22 is eliminated, so that a power generation plan can be created with a shorter calculation time.

[0051] (Modification) In the second embodiment, the objective function of formula (1) is replaced with the following formula (12) to solve the optimization problem as a mixed integer linear programming problem, thereby reducing the amount of calculation by the first thermal power side optimization problem calculation unit 22.

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[0052] In this way, the power generation plan generating device 1 of the modified example can perform calculations that avoid integerity, i.e., combinatorial explosion. Therefore, the amount of calculations in the first thermal power optimization problem calculation unit 22 is reduced, and it is possible to create an efficient power generation plan while shortening the calculation time.

[0053] (Other embodiments) In this specification, an embodiment of the present invention has been described, but this embodiment is presented as an example and is not intended to limit the scope of the invention. The above-mentioned embodiment can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the scope of the invention. The embodiment and its modifications are included in the scope of the invention and its equivalents described in the claims, as well as in the scope and gist of the invention.

[0054] In the above embodiment, the transmitter / receiver 34 transmits the hydropower-side optimal solution calculated by the hydropower-side optimization problem calculation unit 32 to the thermal power generation plan generation unit 2, but is not limited to this. For example, instead of the optimal solution, the total amount of power generation in hydropower generation may be transmitted. Furthermore, uncertainty information may be included. Uncertainty information is information that is difficult to predict accurately in advance (information that may result in an incorrect prediction), such as information that is dependent on weather, such as natural flow flowing into a dam.

[0055] In the above embodiment, the system λ t is the first differential value, and this is transmitted to the hydroelectric power generation. However, this is not limited to this, and the data transmitted to the hydroelectric power generation may be information related to the power generation plan on the thermal power generation side. t This includes the specific power generation volume and power generation plan for thermal power generation calculated based on the optimal solution.

[0056] In the above embodiment, the thermal power generation plan generating unit 2 has a transmitting unit 25 and a receiving unit 26, the hydroelectric power generation plan generating unit 3 has a transmitting unit 34 and a receiving unit 35, and the system λ t In the above, the thermal power generation plan generating unit 2 does not have to have the transmitting unit 25 and the receiving unit 26, and the hydroelectric power generation plan generating unit 3 does not have to have the transmitting unit 34 and the receiving unit 35. In this case, the power generation plan generating device 1 first transmits and receives the system λ t Calculate and store, then, the system λ tThen, taking into account the above, an optimal solution on the hydroelectric power generation side is calculated and stored, and finally, an optimal solution on the thermal power generation side is calculated taking into account the optimal solution on the hydroelectric power generation side, thereby generating power generation plans for both thermal power generation and hydroelectric power generation. [Explanation of symbols]

[0057] 1. Power generation plan generator 2 Thermal power generation plan generation section 21 Memory section 22 First thermal power optimization problem calculation section 23 Second thermal power optimization problem calculation section 24 Thermal power operation plan generation unit 25 Transmitter 26 Receiving section 3. Hydroelectric power generation planning section 31 Storage section 32 Hydropower optimization problem calculation section 33 Hydroelectric power plant operation plan generation unit 34 Transmitter 35 Receiving section

Claims

1. a thermal power generation plan generating unit that generates a power generation plan for a thermal power plant; a hydroelectric power generation plan generating unit for generating a power generation plan for the hydroelectric power plant; Equipped with The thermal power generation plan generation unit, Solving an optimization problem consisting of an objective function and constraint equations, we obtain a system λ that is derived from the optimal solution for the amount of power to be generated in thermal power plants according to the power demand forecast. ｔ A first thermal power side optimization problem calculation unit that calculates a second thermal power side optimization problem calculation unit that solves the optimization problem while taking into account the hydroelectric power side optimal solution calculated by the hydroelectric power generation plan generation unit, and calculates a thermal power side optimal solution; having The hydroelectric power generation plan generating unit is ｔ a hydroelectric power generation plan generating device having a hydroelectric power generation side optimization problem calculation unit that solves the optimization problem on the hydroelectric power generation side so as to maximize the reduction in the power generation cost of the thermal power plant, taking into account the above.

2. The first thermal power side optimization problem calculation unit solves the optimization problem by relaxing at least some of the conditions of the objective function and the constraint equation to obtain the system λ ｔ The power generation plan generating device according to claim 1 , further comprising:

3. A power generation plan generating method including a thermal power generation plan generating unit that generates a power generation plan for a thermal power plant, and a hydroelectric power generation plan generating unit that generates a power generation plan for a hydroelectric power plant, Solving an optimization problem consisting of an objective function and constraint equations, we obtain a system λ that is derived from the optimal solution for the amount of power to be generated in thermal power plants according to the power demand forecast. ｔ A first thermal power side optimization problem calculation step of calculating The system λ ｔ a hydropower optimization problem calculation step for solving the hydropower optimization problem by taking into account the above and calculating the hydropower optimization solution; a second thermal power side optimization problem calculation step of solving the optimization problem by taking into account the hydroelectric power side optimal solution and calculating a thermal power side optimal solution; A power generation plan generating method comprising:

4. In the first thermal power side optimization problem calculation step, the optimization problem is solved by relaxing at least some of the conditions of the objective function and the constraint equation to solve the system λ ｔ The power generation plan generating method according to claim 3, further comprising the steps of:

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