AU2020200488A1

AU2020200488A1 - Operation plan creating apparatus, operation plan creating method, and program

Info

Publication number: AU2020200488A1
Application number: AU2020200488A
Authority: AU
Inventors: Jin Murata; Hidekazu Saito; Tsuneo Watanabe; Shotaro Yamane; Takufumi Yoshida
Original assignee: Toshiba Corp
Current assignee: Toshiba Corp
Priority date: 2016-11-01
Filing date: 2020-01-23
Publication date: 2020-02-13
Also published as: JP2018074836A; TW201824043A; JP6652481B2; TWI653544B; AU2017248562A1

Abstract

In one embodiment, an operation plan creating apparatus includes a first, a second and a third calculator. The apparatus creates the operation plan of the generator regarding an amount of 5 power generation. The first calculator calculates a virtual output limit on the basis of at least the output variation rate and the load retention period. The second calculator calculates a power generation amount limit value in the time frame on the basis of the virtual output limit; the initial value of the magnitude of the output 10 power and the initial value of the increase/decrease direction of the output power in the time frame; and the initial value of the load retention remaining time in the time frame. The third calculator calculates the amount in the time frame by solving an optimization problem that includes at least the limitation condition associated with 15 the power generation amount limit value. (Fig. 1) D CF- 0 Z">lLD4 z 0- 9Cx r- D W <I D Z) Z) Q9 -LU 2: o 0 0>0 D D~ Z zzj m c~zuJ 3Cz-J Z 0~ (~90 0

Description

OPERATION PLAN CREATING APPARATUS, OPERATION PLAN CREATING METHOD, AND PROGRAM

FIELD

An embodiment relates to an operation plan creating apparatus, an operation plan creating method, and a program.

BACKGROUND

Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.

Creation of an operation plan for a generator is one of the important tasks for a power generation department or the like of a general electric utility corporation. The operation plan is created such that the generator outputs an amount of electrical power that corresponds to a power demand predicted for a predetermined time period.

However, when the output power of the generator needs to vary, an output variation rate and a load retention period become limitation conditions. The output variation rate is a degree of change in the output power of the generator. The load retention period is a time period in which an output power value of the generator is continued by retaining a load for the generator when the output power value becomes equal to a predetermined value. Hence, it is not possible to change the output power of the generator until the load retention period elapses. Accordingly, there is a problem that it is not possible to create an accurate operation plan if these two limitation conditions are not taken into account.

SUMMARY

One embodiment provides an operation plan creating apparatus creating an operation plan of a generator regarding an amount of power generation by the generator, the apparatus comprising:

a virtual output limit calculator configured to calculate a

2020200488 23 Jan 2020 virtual output limit of the generator on the basis of at least an output variation rate of the generator and a load retention period of the generator;

a power generation amount limit value calculator configured to calculate a power generation amount limit value of the generator in a time frame on the basis of a virtual output limit; an initial value of a magnitude of an output power of the generator and an initial value of an increase/decrease direction of the output power of the generator in the time frame; and an initial value of a 10 load retention remaining time of the generator in the time frame;

and a power generation calculator configured to calculate the amount of power generation of the generator in the time frame by solving an optimization problem that includes at least a limitation 15 condition associated with the power generation amount limit value.

One embodiment provides an operation plan creating method for creating an operation plan of a generator regarding an amount of power generation by the generator, the method 20 comprising:

a virtual output limit calculating step of calculating a virtual output limit of the generator on the basis of at least an output variation rate of the generator and a load retention period of the generator;

a power generation amount limit value calculating step of calculating a power generation amount limit value of the generator in a time frame on the basis of a virtual output limit; an initial value of a magnitude of an output power of the generator and an initial value of an increase/decrease direction of the output 30 power of the generator in the time frame; and an initial value of a load retention remaining time of the generator in the time frame; and a power generation calculating step of calculating the amount of power generation of the generator in the time frame by 35 solving an optimization problem that includes at least a limitation condition associated with the power generation amount limit

2020200488 23 Jan 2020 value.

One embodiment provides a program for creating an operation plan of a generator regarding an amount of power generation by the generator, the program causing a computer to execute:

a power generation amount limit value calculating step of 15 calculating a power generation amount limit value of the generator in a time frame on the basis of a virtual output limit; an initial value of a magnitude of an output power of the generator and an initial value of an increase/decrease direction of the output power of the generator in the time frame; and an initial value of a 20 load retention remaining time of the generator in the time frame;

and a power generation calculating step of calculating the amount of power generation of the generator in the time frame by solving an optimization problem that includes at least a limitation 25 condition associated with the power generation amount limit value.

Unless the context clearly requires otherwise, throughout the description and the claims, the words comprise, comprising, and the like are to be construed in an inclusive 30 sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of including, but not limited to.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an example of a 35 schematic configuration of an operation plan creating apparatus in accordance with an embodiment of the present invention.

2020200488 23 Jan 2020

FIGS. 2A and 2B are diagrams for explanation of generator operation data.

FIGS. 3A and 3B are diagrams for explanation of a virtual output limit.

FIGS. 4A and 4B are diagrams illustrating an example of calculation of a power generation amount limit value.

FIGS. 5A and 5B are diagrams illustrating another example of calculation of the power generation amount limit value.

FIG. 6 is a diagram for explanation of processing of a next 10 time frame initial value calculator 15.

FIG. 7 is a diagram illustrating an example of an operation plan.

FIG. 8 is a diagram illustrating an example of a schematic flowchart of overall processing of the operation plan creating 15 apparatus in accordance with this embodiment.

FIG. 9 is a block diagram illustrating an example of a hardware configuration of the operation plan creating apparatus in accordance with this embodiment.

DETAILED DESCRIPTION

An embodiment of the present invention creates an operation plan of a generator which takes into account an output variation rate and a load retention period.

An operation plan creating apparatus in accordance with one 25 embodiment of the present invention includes a virtual output limit calculator, a power generation amount limit value calculator, and a power generation calculator. The operation plan creating apparatus is configured to create the operation plan of the generator regarding an amount of power generation by the generator. The virtual output 30 limit calculator is configured to calculate a virtual output limit of the generator on the basis of at least the output variation rate of the generator and the load retention period of the generator. The power generation amount limit value calculator is configured to calculate a power generation amount limit value of the generator in the time 35 frame on the basis of the virtual output limit; the initial value of the magnitude of the output power of the generator and the initial value of the increase/decrease direction of the output power of the generator in the time frame; and the initial value of the load retention remaining time of the generator in the time frame. The power generation calculator is configured to calculate the amount of power generation of the generator in the time frame by solving an optimization problem that includes at least the limitation condition associated with the power generation amount limit value.

An embodiment of the present invention will be described below with reference to the drawings.

(Embodiment of the Present Invention)

FIG. 1 is a block diagram that illustrates an example of a schematic configuration of an operation plan creating apparatus in accordance with an embodiment of the present invention. The operation plan creating apparatus 1 illustrated in FIG. 1 includes a storage (obtainer) 11, a virtual output limit calculator 12, a power generation amount limit value calculator 13, a power generation calculator 14, a next time frame initial value calculator 15, and an operation plan creator 16.

The operation plan creating apparatus 1 is configured to create an operation plan for a generator on the basis of a limitation condition (limitation expressions) and an objective function, the limitation condition being for a power demand or the like to be predicted, and the objective function being indicative of a predetermined objective. The created operation plan is related to the amount of power generation that is output by the generator in a predetermined time frame. In addition, it is assumed here that the amount of power generation that has been calculated takes into account at least the two limitation conditions of the generator which are an output variation rate and a load retention period.

The time frame is part of the time period for which the operation plan is created. The time frame may be defined based on a time period during which the amount of power generation output by the generator must coincide with the predicted power demand. For example, if the simultaneous balancing (the consistency between the power demand and the amount of power generation) for 30 minutes is to be considered, then the length of the time frame may

2020200488 23 Jan 2020 be defined as 30 minutes. It should also be noted that the amount of power generation may be the amount of power generation for one single generator or may be the total amount of power generation by multiple generators. The whole time period of the operation plan to 5 be created is composed of a successive multiple time frames. In other words, the operation plan to be created will be a set of the respective amounts of power generation in the respective time frames. The length of the time frame and the length of the whole time period of the operation plan to be created are not limited to 10 particular ones.

It should be noted that the types of the generator are not limited to particular ones as long as the generator is compatible with the above-described output variation rate and load retention period. The generators may include a generator of thermal, hydraulic, or 15 nuclear power generation. The generators may also include a generator that utilizes renewable energy, including wind, photovoltaic, geothermal, and biomass energies, or any other form of energy. The generators may further include a generator of hydrogen power generation. Also, the types of the generators 20 may be the same or different from each other.

The constituent components of the operation plan creating apparatus 1 will be described in detail below.

The storage (obtainer) 11 is configured to obtain, as data, information for use in creation of the operation plan and store the 25 information that has been obtained. The information for use in creation of the operation plan includes information regarding the objective function and information regarding the limitation conditions. For example, if the objective is reduction of the operation cost that indicates costs associated with the operation of 30 the generator, then the operation cost per unit amount of electrical power of the generator is stored in the storage 11. Also, for example, if the operation cost is calculated from the costs of the items such as fuel used by the respective generators, the information regarding the costs of the items may also be stored in 35 the storage 11.

Also, as the information regarding the limitation conditions, a

2020200488 23 Jan 2020 power demand predicted in the time period of the operation plan to be created is stored in the storage 11. Since the power demand is the electrical power that multiple generators should accommodate, it will also necessary to provide information regarding the amounts of 5 electrical power that can be output by the individual generators.

Hence, the information regarding the operation of the generators is also stored in the storage 11. The data indicative of the information regarding the operation of the generator stored in the storage 11 is hereinafter referred to as generator operation data. The output 10 variation rate of the generator and the load retention period are also included in the generator operation data.

It should be noted that the operation plan creating apparatus 1 may have multiple storages. In other words, the storage 11 may be configured by multiple storages. For example, 15 multiple storages may exist in the operation plan creating apparatus 1 and the types of the pieces of information which is stored in the respective storages may differ from each other.

The information stored in the storage 11 may be stored in the storage 11 by the user prior to actual creation of the operation 20 plan or may be obtained from an external device or system by the operation plan creating apparatus 1 to store it in the storage 11. As can be seen from the example illustrated in FIG. 1, the operation plan creating apparatus 1 may obtain the power demand from the power demand prediction system 2, obtain the generator operation 25 data from the generator operation data obtaining system 3, and obtain the information regarding the operation conditions of the generator that have been entered by a user via the input/output interface 4. The data indicative of the information regarding the operation conditions of the generator stored in the storage 11 is 30 hereinafter referred to as operation condition data. The information indicated by the operation condition data may encompass pieces of information whose values vary within the time period for which the operation plan is to be created, e.g., the maintenance interval of the generator, fuel cost, etc.

It should be noted that if the information is obtained from an external device or system as illustrated in FIG. 1, the operation plan creating apparatus 1 is directly connected or indirectly connected to the external device or system via a communication interface or a device interface so that transmission and reception of data can be performed. The information necessary for transmission and reception of data such as an IP address and the like may be stored in the storage 11 prior to the creation of the operation plan.

Also, the storage 11 may obtain and store the results of the processing by the individual constituent components of the operation plan creating apparatus 1. For example, the storage 11 may store the operation plan that has been created, and the like. Also, the information stored in the storage 11 may be output on the input/output interface 4 or sent to an external device or system.

The virtual output limit calculator 12 is configured to calculate virtual output limits of the generator on the basis of the generator operation data. The generator operation data includes at least a piece of data regarding the output variation rate of the generator and a piece of data regarding the load retention period of the generator. The virtual output limits include a virtual output upper limit and a virtual output lower limit. The virtual output upper limit indicates the time-series transition of the upper limit value of the output power in a case where the generator is assumed to gradually increase its output power. The virtual output lower limit indicates time-series transition of the lower limit value of the output power in a case where the generator is assumed to gradually lower its output power. Note that, if either of the virtual output upper limit and the virtual output lower limit is not taken into account, then the one that is not taken into account may not be included in the virtual output limits.

FIGS. 2A and 2B are diagrams for explanation of the generator operation data. FIG. 2A is a diagram that illustrates an example of the data regarding the output variation rate included in the generator operation data. The table illustrated in FIG. 2A includes the fields of UNIT ID, DIRECTION, OUTPUT LOWER LIMIT, OUTPUT UPPER LIMIT, and OUTPUT VARIATION RATE. The unit ID represents the identification number of a generator. The direction represents the direction of increase or decrease in the output power.

2020200488 23 Jan 2020

RISING indicates the fact that the output power is gradually increased. FALLING indicates the fact that the output power is gradually decreased. The output lower limit and the output upper limit represent the lower limit value and the upper limit value, 5 respectively, in the range of the output power. The output variation rate represents the degree of change in the output power of the generator in the range defined by the output lower limit and the output upper limit. For example, the second row from the top of FIG. 2A indicates that, when the output power of the generator whose unit 10 ID is 1 is increased within the range from 100 megawatts (MW) to

200 MW, the output variation rate of the output power is 5 megawatts per minute (MW/min).

FIG. 2B is a diagram that illustrates an example of data regarding the load retention period which is one of the pieces of the 15 generator operation data. The table illustrated in FIG. 2B includes the fields of unit id, direction, output, and load retention period. The output indicates the output power value that corresponds to the load retention period (magnitude of the output power). The load retention period indicates the time period during which the output 20 power value is continued (keeps constant) in a case where the output power of the generator increases, reaches the value indicated in the output, and further increases beyond this indicated value, or in a case where the output power decreases, reaches the value indicated in the output, and further decreases beyond this indicated value. 25 For example, the second row from the top of FIG. 2B indicates that the load retention period when the output power of the generator whose unit ID is 1 increased and reached 200 MW is 30 minutes. In other words, it indicates that the output power of the generator whose unit ID is 1, is maintained at 200 MW for 30 minutes when 30 the output power increases, reaches 200 MW, and further increases beyond 200 MW.

FIGS. 3A and 3B are diagrams for explanation of the virtual output limits. FIG. 3A is a diagram that illustrates the virtual output upper limit. FIG. 3B is a diagram that illustrates the virtual output 35 lower limit. The horizontal axes of FIGS. 3A and 3B represent the elapsed time, and the vertical axes indicate the output power.

2020200488 23 Jan 2020

As illustrated in FIGS. 3A and 3B, the graph of the virtual output limits satisfies the output variation rate and the load retention period illustrated in FIGS. 2A and 2B. For example, with regard to the graph of the virtual output upper limit of FIG. 3A, as can be seen 5 from the second row from the top of FIG. 2A, the slope of the graph indicating the output variation rate is 5 in the range where the output lower limit is 100 MW and the output upper limit is 200 MW. Hence, the output power increases for 20 minutes from 100 MW to 200 MW. In addition, as can be seen from the second row from the top of FIG.

2B, the load retention period at the time when the output power increased and reached 200 MW is 30 minutes, so that the graph of the virtual output upper limit of FIG. 3A will be at a constant level of 200 MW for the time interval from 20 minutes to 50 minutes. It should be noted that the time slot in which the output power is constant according to the load retention period is hereinafter referred to as load retention time slot. It should also be noted that FIG. 3A assumes that the maximum output power is 500 MW, so that the output power will not increase after the output power reaches 500 MW.

The graph of the virtual output lower limit also satisfies the output variation rate and the load retention period of the generator operation data in the same manner as the graph of the virtual output upper limit. For example, with regard to the graph of the virtual output lower limit of FIG. 3B, the slope of the graph indicating the output variation rate is 10 within the range where the output lower limit is 200 MW and the output upper limit is 500 MW, as can be seen from the fifth row from the top of FIG. 2A. Hence, the output power decreases from 500 MW to 200 MW for 30 minutes. In addition, as can be seen from the fourth row from the top of FIG. 2B, the load retention period at the time at which the output power decreased and reached 200 MW is 50 minutes, so that the graph of the virtual output lower limit of FIG. 3A remains at the constant level of 200 MW for the time interval from 30 minutes to 80 minutes. It should be noted that FIG. 3B assumes that the minimum output power is 100 MW, so that the output power will not decrease after the output power becomes as low as 100 MW.

2020200488 23 Jan 2020

The power generation amount limit value calculator 13 is configured to calculate the power generation amount limit value of the generator in the time frame on the basis of virtual output limits, on the basis of the initial value of the magnitude of the output power 5 of the generator in the time frame and the initial value of the increase/decrease direction of the output power of the generator in the time frame, and on the basis of the initial value of a load retention remaining time of the generator in the time frame. The virtual output limits include at least a virtual output upper limit or a virtual 10 output lower limit, so that the calculated power generation amount limit value will include at least the upper limit value or the lower limit value of the amount of power generation.

The load retention remaining time is a remaining time period for which the output power value continues. The load retention 15 remaining time means the time period until the output power changes. The load retention remaining time is calculated by subtracting the time period (continuation time) in which the output power value continued from the load retention period corresponding to the output power value. The initial value of the load retention 20 remaining time of the time frame means the load retention remaining time at the time of the beginning of the time frame. For example, if the output power value continued at the time of the end of a first time frame, then, in the second time frame, the remaining time obtained by subtracting the continuation time of the output power value in the 25 previous time frame from the load retention period will be the time for which the output power value continues in the second time frame. Thus, this remaining time will be the initial value of the load retention remaining time of the second time frame.

FIGS. 4A and 4B are diagrams that illustrate an example of 30 how the power generation amount limit value is calculated. In the explanation with reference to FIGS. 4A and 4B, it is assumed that the initial value of the magnitude of the output power in the time frame is specified as 300 MW, the initial value of the increase/decrease direction is specified as RISING (increase), and the initial value of 35 the load retention remaining time of the time frame is specified as 0. FIG. 4A is a diagram that illustrates an example of how the

2020200488 23 Jan 2020 power generation amount upper limit value is calculated using the virtual output upper limit. When the initial value of the load retention remaining time is specified as 0, it is possible to immediately change the output power, so that, from the time point at 5 which the output power reaches the specified value until the completion of the time period of the time frame, the area defined by the horizontal axis and the graph of the virtual output upper limit will be the power generation amount upper limit value in this time frame.

For example, referring to FIG. 4A, the output power becomes 10 300 MW when the time indicates 60 minutes. Hence, if the length of the time frame is 30 minutes, the area defined by the horizontal axis and the graph of the virtual output upper limit within the interval from 60 minutes to 90 minutes will be the power generation amount upper limit value to be obtained. Accordingly, the calculated power 15 generation amount upper limit value will be 192 megawatt-hours (MWh).

FIG. 4B is a diagram that illustrates an example of how the power generation amount lower limit value is calculated using the virtual output lower limit. Referring to FIG. 4B, the output power 20 becomes 300 MW when the time indicates 20 minutes. Hence, if the length of the time frame is 30 minutes, then the area defined by the horizontal axis and the graph of the virtual output lower limit within the interval from 20 minutes to 50 minutes will be the power generation amount lower limit value to be obtained. Accordingly, 25 the calculated power generation amount lower limit value will be 108 MWh.

FIGS. 5A and 5B are diagrams that illustrate another example of how the power generation amount limit value is calculated. In FIGS. 4A and 4B, only one time point is given where the output power 30 becomes equal to the specified value. In contrast, referring to FIGS.

5A and 5B, the case where the specified output power is an output power associated with the load retention time slot, in other words, the case where the time point at which the output power takes a specified value extends over a certain time period will be explained.

In the explanation with reference to FIGS. 5A and 5B, it is assumed that the initial value of the magnitude of the output power is specified

2020200488 23 Jan 2020 as 200 MW, the initial value of the increase/decrease direction is specified as RISING, and the initial value of the load retention remaining time is specified as 20 minutes.

When the time point at which the output power becomes equal to the specified value extends over a certain time period, the time point at which the time up to the time point of the output power changing from the specified initial value coincides with the initial value of the load retention remaining time will be identified as the time point at which the calculation of the power generation amount 10 limit value is started. This is because, if the time equal to the load retention remaining time elapses, then the generator is allowed to change its output power. For example, referring to FIG. 5A, the output power is 200 MW in the time interval from 20 minutes to 50 minutes. However, since the load retention remaining time is 15 specified as 20 minutes, the time point of 30 minutes will become the time point at which the calculation of the power generation amount limit value is started, which is because, at the time point of 30 minutes, the time period to 50 minutes at which the output power changes from 200 MW coincides with the specified load retention 20 remaining time which is 20 minutes. Hence, if the length of the time frame is 30 minutes by definition, then the area defined by the horizontal axis and the graph of the virtual output upper limit within the interval from the beginning of the time frame (the time point of 30 minutes) to the end of the same time frame (the time point of 60 25 minutes) will be the power generation amount upper limit value to be obtained. Accordingly, the calculated power generation amount upper limit value is 108 MWh.

Referring to FIG. 5B, the output power becomes 200 MW when the time is between 30 minutes and 80 minutes. However, 30 since the initial value of the increase/decrease direction is not FALLING (decrease), even when the load retention remaining time is specified as 20 minutes, the time point of 80 minutes at which the output power changes from 200 MW will be the time point at which the calculation of the power generation amount limit value is started. 35 Hence, if the length of the time frame is 30 minutes by definition, then the area defined by the horizontal axis and the graph of the

2020200488 23 Jan 2020 virtual output lower limit within the interval from the beginning of the time frame (the time point of 80 minutes) to the end of the time frame (the time point of 110 minutes) will be the power generation amount lower limit value to be obtained. Accordingly, the calculated 5 power generation amount lower limit value is about 67 MWh.

In this manner, the power generation amount limit value calculator 13 calculates the power generation amount upper limit value using the virtual output upper limit and calculates the power generation amount lower limit value using the virtual output lower 10 limit on the basis of the initial value of the magnitude of the output power of the time frame and the initial value of the increase/decrease direction, and on the basis of the initial value of the load retention remaining time of the time frame. It should be noted that the initial value of the magnitude of the output power and the initial value of 15 the increase/decrease direction of the output power in the first time frame which the power generation amount limit value calculator 13 processes, and the initial value of the load retention remaining time are stored in advance in the storage 11. Also, the initial value of the magnitude of the output power and the initial value of the 20 increase/decrease direction of the output power in the first and subsequent time frames, and the initial value of the load retention remaining time are calculated by the next time frame initial value calculator 15. Details will be described later.

The power generation calculator 14 calculates the output 25 power determined as being appropriate by solving the optimization function according to the given objective function and subject to the given limitation conditions. The amount of power generation is calculated for each time frame. The limitation conditions of the optimization problem whose solution is to be sought include at least 30 a limitation condition associated with the power generation amount limit value. The following expression is an expression that illustrates an example of the objective function and its limitation conditions in a certain time frame.

[Equation 1]

2020200488 23 Jan 2020 ι

min: ^cosT) (x_t ,u_£)(1) i=l

S.t.

LOWERt X Ui < Xi< UPPERi X u_£ (2) {x_£, u_£} G G(3) x_£ E R +(4) ut E {0,1}(5)

The expression (1) of Equation 1 represents the objective function. The objective function means that the sum of the operation costs of generators should be reduced, where i is an 10 integer not smaller than 1 and not larger than I (where I is a positive integer) and represents the identification number of the generator (the unit ID); I represents the total number of the generators for which the operation plan is to be created; xi is a continuous variable and represents the amount of power generation 15 of the generator i; and ur is a discrete variable and represents the operational state of the generator i. The expression (5) indicates the limitation condition that indicates the values that Ui can take. According to the expression (5), ui will take the value of either 0 or

1. Hence, there are two types of the operational states of the 20 generator i. For example, the operational states include two types of OPERATING and STOPPING, and Ui may be defined as 1 when the operational state of the generator i is an OPERATING and Ui may be defined as 0 when the operational state is a STOPPING. COST, (Xi, Ui) represents a function that indicates the operation cost 25 when the amount of power generation of the generator i is Xi and the state of the generator i is Ui.

The expressions (2) to (5) represent limitation conditions. The expression (2) is a limitation condition associated with the power generation amount limit value of the generator, and indicates the 30 range of values that the amount of power generation Xj is allowed to take. LOWER, represents the power generation amount lower limit value of the generator i which has been calculated by the power generation amount limit value calculator 13. UPPERi represents the power generation amount upper limit value of the generator i

2020200488 23 Jan 2020 which has been calculated by the power generation amount limit value calculator 13. As can be appreciated from the expression (2), the optimization problem includes at least the limitation condition associated with the power generation amount limit value.

G in the expression (3) represents the feasible area constituted by other limitation conditions. For example, operation conditions such as the power demand and maintenance are used as limitation conditions for calculating the feasible area G. Hence, the expression (3) is a limitation condition that indicates the 10 combinations which the amount of power generation x, and the operational state u, can form. R+ of the expression (4) represents a set of non-negative real numbers. Hence, the expression (4) indicates the limitation condition that the amount of power generation Xi must be a non-negative real number.

It should be noted that the above-described optimization problem can be handled by a solver or the like. Hence, the power generation calculator 14 can be realized using a solver. For example, when the objective function and the limitation condition expressions are expressed by a relatively low-dimensional expression such as a 20 linear or quadratic expression, a general-purpose solver may be used. Also, a new solver may be created.

It should be noted that it suffices that the operation cost is a cost associated with the operation of the generator, and costs associated with the items, persons, or services necessary for the 25 operation of the generator may be included therein. The items necessary for the operation of the generator may include power source for power generation such as fuel and cooling water, catalyst, and the like other than the power source. The power source is not limited to a particular one. For example, the power 30 source may include fossil fuel, wood fuel, nuclear fuel, and the like.

It may include pumped-up water stored in a dam or the like. It may further include chemical substances such as methylcyclohexane used in hydrogen power generation. Also, costs incurred by operation of the generator may also be included.

For example, the cost related to limestone and liquid ammonia for use in removing chemical substances contained in the exhaust gas generated by power generation may be included in the operation cost. It is also possible to recognize that the operation cost occurs due to the above costs even when the generator is stopped.

Although the above-described objective function is the sum of the operation costs of the respective generators, the objective function may be the sum of the operation costs of some of the particular generators. For example, a generator that belongs to a particular group may be taken into account whilst the operation costs of generators that do not belong to this particular group are not taken into account. Also, instead of simple aggregation of the operation costs of the respective generators, operation costs of the respective generators may be multiplied, for example, by weighting factors and then aggregated, and thus weighting of the generators may be provided.

Although the objective function whose objective is to reduce the operation cost is described in the foregoing description, it is also possible to create objective functions based on any other cost, and it is also possible to create objective functions based on multiple costs.

The next time frame initial value calculator 15 calculates, on the basis of the amount of power generation of the generator and the virtual output limit, the output power value of the generator at the time of the end of the time frame in which the amount of power generation has been calculated and the continuation time of the output power value. Then the next time frame initial value calculator 15 calculates, on the basis of the output power value and the continuation time, the initial value of the magnitude of the output power of the generator, the initial value of the increase/decrease direction of the output power of the generator, and the initial value of the load retention remaining time in the next time frame following the time frame for which the amount of power generation has been calculated.

FIG. 6 is a diagram for explanation of the processing of the next time frame initial value calculator 15. The dashed line in FIG. 6 indicates the virtual output line that has been calculated by the next time frame initial value calculator 15. The virtual output line indicates the time-series data of the virtual output. The virtual

2020200488 23 Jan 2020 output indicates the virtual output power of the generator that has been calculated by the next time frame initial value calculator 15 such that the amount of power generation of the generator in the time frame coincides with the amount of power generation that has been calculated by the power generation calculator 14. The area defined by the horizontal axis and the virtual output line within the time frame will be the amount of power generation of the generator in this time frame.

The virtual output line is calculated based on the amount of 10 power generation of the generator and the virtual output limit. First, the next time frame initial value calculator 15 compares the amount of power generation, which assumes that the output power value at the time of the beginning of the time frame continues until the end of the time frame, with the amount of power generation that has been 15 calculated by the power generation calculator 14. If the amount of power generation based on this assumption is smaller than the amount of power generation that has been calculated by the power generation calculator 14, then it is necessary to raise the output power, and the virtual output line is calculated using the virtual 20 output upper limit. If the former is larger than the latter, then it is necessary to lower the output power, and the virtual output line is calculated using the virtual output lower limit.

For example, if it is assumed that the amount of power generation in the time frame is calculated as 172 MWh, the next time 25 frame initial value calculator 15 checks the output power value at the time of the beginning of the time frame. As illustrated in FIG. 6, if the output power value at the time of the beginning of the time frame is 300 MW, then the amount of power generation in the time frame of 30 minutes in the case where the output power value is continued will 30 be 150 MWh, which is smaller than the amount of power generation of 172 MWh. Hence, it is necessary to raise the output power, and the next time frame initial value calculator 15 calculates the virtual output line using the virtual output upper limit.

The virtual output line should be calculated such that the 35 output variation rate and the virtual output limit are satisfied.

Specifically, it should be ensured that the slope of the virtual output

2020200488 23 Jan 2020 line coincides with the output variation rate and the virtual output line is included in the range between the virtual output upper limit and the virtual output lower limit. For example, the virtual output line may be calculated by a method according to which the virtual 5 output upper limit or the virtual output lower limit is shifted in parallel with the time axis in its positive direction. According to this method, since the graphs of the virtual output upper limit and the virtual output lower limit are calculated based on the output variation rate, the slope of the virtual output line will also coincide with the output 10 variation rate. Also, since the parallel shift tales place, the virtual output line is included in the range of the virtual output upper limit and the virtual output lower limit.

The next time frame initial value calculator 15 calculates, on the basis of the virtual output line that has been calculated, the initial 15 value of the magnitude of the output power in the next time frame and the initial value of the increase/decrease direction of the output power in the next time frame, and the initial value of the load retention period of the output power in the next time frame. For example, if the virtual output line in the first time frame has been 20 calculated as illustrated in FIG. 6, then the value of the virtual output line at the time of the end of the first time frame is 400 MW, so that the next time frame initial value calculator 15 calculates the initial value of the output power in the second time frame which is the next time frame as 400 MW. Also, if the output power value becomes 400 25 MW at the time point of 22 minutes within the first time frame, then the value of the output power will continue to be 400 MW for eight minutes until the next time frame. As illustrated in FIG. 2B, the load retention period in which the increase/decrease direction indicates rising and the output power becomes 400 MW is 30 minutes, so 30 that the load retention remaining time will be 22 minutes.

Accordingly, the next time frame initial value calculator 15 calculates the initial value of the load retention remaining time in the next time frame as 22 minutes.

The initial values of the parameters in the next time frame 35 that have been calculated by the next time frame initial value calculator 15 will be used by the power generation amount limit value

2020200488 23 Jan 2020 calculator 13 to calculate the power generation amount limit value in the next time frame. Then the processes by the power generation calculator 14 and the next time frame initial value calculator 15 will be performed again for the next time frame. In this manner, when 5 the amount of power generation in a certain time frame is calculated, the initial values of the next time frame are identified, making it possible to calculate the amount of power generation in the next time frame.

The operation plan creator 16 aggregates the amounts of 10 power generation in the respective time frames calculated by power generation calculator 14 and thereby creates the operation plan. FIG. 7 is a diagram that illustrates an example of the operation plan. The table illustrated in FIG. 7 includes the fields of START DATE AND TIME, TIME FRAME ID, UNIT ID, and GENERATED POWER AMOUNT. 15 The time frame ID indicates the identification number of the time frame. The start date and time indicate the date and time of the time point of the beginning of the time frame indicated in the time frame ID field. The generated power amount indicates the amount of power generation of the generator indicated in the unit ID field in 20 the time frame indicated in the time frame ID. In this manner, the operation plan that has been created by the operation plan creator 16 is an operation plan regarding the amounts of power generation of the generator(s) in the time frames. It should be noted that the operation plan to be created may include the other processing results 25 such as the power generation amount upper limit value in addition to the amount of power generation.

Next, the processing flow of the constituent components will be described below.

FIG. 8 is a diagram that illustrates an example of a 30 schematic flowchart of the overall processing of the operation plan creating apparatus 1 in accordance with this embodiment. The storage 11 obtains and stores the information necessary for creation of the operation plan (S101). After the necessary information has been stored, the virtual output limit calculator 12 calculates the 35 virtual output limit on the basis of the information regarding the

2020200488 23 Jan 2020 output variation rate and the load retention period stored in the storage 11 (S102).

The power generation amount limit value calculator 13 calculates the power generation amount limit value on the basis of 5 the virtual output limit, the initial value of the magnitude of the output power and the initial value of the increase/decrease direction in the time frame, and the initial value of the load retention period in this time frame (S103). The power generation calculator 14 solves the optimization problem including the calculated power generation 10 amount limit value as one of its limitation conditions, and thereby calculates the amount of power generation in this time frame (S104). Then the next time frame initial value calculator 15 calculates the virtual output line that satisfies the calculated amount of power generation and thereby calculates the initial value of the magnitude 15 of the output power and the initial value of the increase/decrease direction in the next time frame, and the initial value of the load retention period in the next time frame (S105). The respective initial values that have been calculated are used in the processing of the calculation of the power generation amount limit value of the 20 next time frame of the power generation amount limit value calculator 13. The processes of the steps S103 to S105 are repeated and the respective amounts of power generation for all of the time frames are calculated.

The operation plan creator 16 aggregates the amounts of 25 power generation that have been calculated for the respective time frames and creates the operation plan (S106). The operation plan that has been created is sent to the storage 11, the storage 11 stores the operation plan that has been obtained (S107), and then the process is completed.

It should be noted that this flowchart is merely an example and the order and the like of the processing are not limited to particular ones as long as the necessary processing results are allowed to be obtained. For example, although the process of the step S106 is described as being performed after the amounts of 35 power generation have been calculated for all the time frames, it may also be performed in parallel with the process of the step S105, and

2020200488 23 Jan 2020 the operation plan creator 16 may add the amount of power generation of a new time frame to the table indicating the operation plan every time the process of the step S106 is performed, and thereby update the operation plan. Also, the processing result of 5 the respective processes may be successively stored in the storage 11 and the individual constituent components may refer to the storage 11 to obtain the processing results.

As has been described in the foregoing, according to this embodiment, the power generation amount limit value for each time 10 frame is calculated using the virtual output limits based on the output variation rate and the load retention period. Since the amount of power generation associated with the operation plan is calculated based on the power generation amount limit value, it is made possible to create the operation plan of the generator that takes into 15 account the output variation rate and the load retention period.

It should be noted that the above-described embodiment is merely an example and some of the constituent components of the above-described embodiment may be provided in an external device and the operation plan creating apparatus 1 may be 20 configured by multiple apparatuses that are capable of exchanging data by communications or electrical signals. In other words, the operation plan creating apparatus 1 may be a system that is configured by multiple apparatuses. For example, although the above-described embodiment includes the virtual 25 output limit calculator 12, the virtual output limit calculator 12 may be provided in an external device. In this case, the storage 11 may obtain the virtual output limit from the external device and deliver it to the power generation amount limit value calculator 13.

Also, the individual processes in accordance with the 30 above-described embodiment can be implemented by software (program). Hence, the above-described embodiment can be implemented, for example, by using a general-purpose computer as its basic hardware and causing a processor such as a central processing unit (CPU) incorporated in the computer to execute the 35 program.

FIG. 9 is a block diagram that illustrates an example of the

2020200488 23 Jan 2020 hardware configuration of the operation plan creating apparatus 1 in accordance with this embodiment. The operation plan creating apparatus 1 includes a processor 51, a main storage apparatus 52, an auxiliary storage apparatus 53, a network 5 interface 54, and a device interface 55. The operation plan creating apparatus 1 can be implemented as a computer 5 in which these components are interconnected via a bus 56. Also, the operation plan creating apparatus 1 may include a general-purpose input apparatus and output apparatus for the 10 implementation of the input/output interface 4.

The operation plan creating apparatus 1 in accordance with this embodiment may be implemented by installing programs executed by the individual apparatuses onto the computer 5 in advance, storing the programs in a storage medium such as 15 CD-ROM, or distributing the programs via the network to install them on the computer 5 as appropriate.

The processor 51 is an electronic circuit that includes a control apparatus and an arithmetic apparatus of a processor. The processor 51 carries out arithmetic processing on the basis of 20 data input from the individual internal apparatuses provided inside of the computer 5 and on the basis of the programs, and outputs the calculation results and control signals to the respective apparatuses and the like. More specifically, the processor 51 executes the operating system (OS) of the computer 25 5 and applications, and control the individual apparatuses constituting the computer 5.

The processor 51 is not limited to a specific one as long as it is capable of performing the above-described processing. The processor 51 may be, and not limited to, a general-purpose 30 processor, a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), a controller, a microcontroller, a state machine, and the like. Also, the processor 51 may be an application specific integrated circuit, a field programmable gate array (FPGA), a programmable logic apparatus (PLD), and the like. 35 Also, the processor 51 may be configured by multiple processing apparatuses. For example, the processor 51 may be configured

2020200488 23 Jan 2020 by the combination of a DSP and a microprocessor or may be one or more microprocessors that operate in cooperation with a DSP core.

The main storage apparatus 52 is a storage apparatus that stores instructions executed by the processor 51 and various pieces of data and the like, and information stored in the main storage apparatus 52 is directly read by the processor 51. The auxiliary storage apparatus 53 is a storage apparatus that is different than the main storage apparatus 52. It should be noted 10 that the storage apparatus refers to any appropriate electronic component that is capable of storing electronic information. A volatile memory apparatus used in temporarily storing information such as RAM, DRAM, and SRAM, is mainly used as the main storage apparatus 52, but the main storage apparatus 52 in 15 accordance with the embodiment of the present invention is not limited to such volatile memory apparatuses. The storage apparatuses used as the main storage apparatus 52 and the auxiliary storage apparatus 53 may be a volatile memory apparatus or a non-volatile memory apparatus. The non-volatile 20 memory apparatus includes programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable PROM (EEPROM), non-volatile random-access memory (NVRAM), flash memory, MRAM, and the like. Also, a magnetic or optical data storage apparatus may be used as the 25 auxiliary storage apparatus 53. The data storage may be configured by a magnetic disk such as a hard disk, an optical disk such as DVD, flash memory such as a USB memory apparatus, a magnetic tape, and the like.

It can be said the storage apparatus electrically 30 communicates with the processor if the processor 51 directly or indirectly writes and/or reads information to and/or from the main storage apparatus 52 or the auxiliary storage apparatus 53. It should also be noted that the main storage apparatus 52 may be integrated into the processor. In this case as well, it can be said 35 that the main storage apparatus 52 electrically communicates with the processor.

2020200488 23 Jan 2020

The network interface 54 is an interface for wired or wireless connection to a communication network. The network interface 54 may be configured by any interface that is compliant with any existing communication standard. Although one single 5 network interface 54 is described in this embodiment, more than one network interface 54 may be provided. The output result and the like may be transmitted by the network interface 54 to the external device 7 communicatively connected thereto via the communication network 6. The external device 7 may be an 10 external storage medium, a display apparatus, or a storage device such as a database system.

The device interface 55 is an interface such as a USB interface for connection to an external storage medium that stores the output result and the like. The external storage medium may 15 be any appropriate storage medium such as HDD, CD-R, CD-RW, DVD-RAM, DVD-R, SAN (Storage area network), etc. Connection to a storage apparatus may be established via the device interface 55.

Also, all or part of the computer 5, i.e., all or part of the 20 operation plan creating apparatus 1 may be configured by a dedicated electronic circuit (i.e., hardware) such as a semiconductor integrated circuit incorporating the processor 51, etc. The dedicated hardware may be configured in combination with a storage device such as RAM and ROM.

Although one single computer is illustrated in FIG. 9, the software program may be installed on multiple computers. The individual computers may carry out different portions of the part of the software program to calculate the processing result.

While certain embodiments have been described, these 30 embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments 35 described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents

2020200488 23 Jan 2020 are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.

Claims

1. An operation plan creating apparatus creating an operation plan of a generator regarding an amount of power generation by the generator, the apparatus comprising:

5 a virtual output limit calculator configured to calculate a virtual output limit of the generator on the basis of at least an output variation rate of the generator and a load retention period of the generator;

a power generation amount limit value calculator configured 10 to calculate a power generation amount limit value of the generator in a time frame on the basis of a virtual output limit; an initial value of a magnitude of an output power of the generator and an initial value of an increase/decrease direction of the output power of the generator in the time frame; and an initial value of a load retention 15 remaining time of the generator in the time frame; and a power generation calculator configured to calculate the amount of power generation of the generator in the time frame by solving an optimization problem that includes at least a limitation condition associated with the power generation amount limit value.

2. The operation plan creating apparatus according to claim 1, further comprising a next time frame initial value calculator configured to calculate, on the basis of the amount of power generation of the generator in a first 25 time frame and the virtual output limit, a first initial value indicating an initial value of a magnitude of an output power of the generator in a second time frame which is the next time frame following the first time frame; a second initial value indicating an initial value of an increase/decrease direction of the output power of the generator in 30 the second time frame; and a third initial value of a load retention remaining time of the generator in the second time frame.

3. The operation plan creating apparatus according to claim 2, wherein the next time frame initial value calculator sets an output

35 power value and an increase/decrease direction of an output power of the generator at the time of the end of the first time frame as the

2020200488 23 Jan 2020 first initial value and the second initial value respectively, and sets a remaining time obtained by subtracting a continuation time of the output power value from a load retention period corresponding to the output power value as the third initial value.

4. The operation plan creating apparatus according to claim 3, wherein the next time frame initial value calculator calculates the output power value and the continuation time on the basis of a virtual output line, the virtual output line being generated based on the

10 amount of power generation of the generator in the time frame and the virtual output limit.

5. An operation plan creating method for creating an operation plan of a generator regarding an amount of power generation by the generator, the method comprising:

a virtual output limit calculating step of calculating a virtual output limit of the generator on the basis of at least an output 15 variation rate of the generator and a load retention period of the generator;

a power generation amount limit value calculating step of calculating a power generation amount limit value of the generator in a time frame on the basis of a virtual output limit; an initial value of 20 a magnitude of an output power of the generator and an initial value of an increase/decrease direction of the output power of the generator in the time frame; and an initial value of a load retention remaining time of the generator in the time frame; and a power generation calculating step of calculating the amount 25 of power generation of the generator in the time frame by solving an optimization problem that includes at least a limitation condition associated with the power generation amount limit value.

6. A program for creating an operation plan of a generator regarding an amount of power generation by the generator, the program causing a computer to execute:

a virtual output limit calculating step of calculating a virtual output limit of the generator on the basis of at least an output

2020200488 23 Jan 2020 variation rate of the generator and a load retention period of the generator;

5 a power generation amount limit value calculating step of calculating a power generation amount limit value of the generator in a time frame on the basis of a virtual output limit; an initial value of a magnitude of an output power of the generator and an initial value of an increase/decrease direction of the output power of the 10 generator in the time frame; and an initial value of a load retention remaining time of the generator in the time frame; and a power generation calculating step of calculating the amount of power generation of the generator in the time frame by solving an optimization problem that includes at least a limitation condition 15 associated with the power generation amount limit value.