Contraction model creation system, control amount determination system, and contraction model creation method

Abstract

To provide a contraction model creation system and the like capable of handling cases where multiple external systems are connected to a power system.SOLUTION: The contraction model creation system includes a processing unit that creates external system contraction models 31a and 31b by contracting an external system model which is a model of each of multiple external systems. The multiple external systems are connected to a main system via interconnection points 41 and 42, respectively. The processing unit is configured to cause a display unit to display information including constraint conditions indicating a controllable range of a prescribed electrical physical quantity of the external system at the interconnection points 41 and 42 and an objective function with the electrical physical quantity as a variable with the electrical physical quantity as the external system contraction models 31a and 31b while being associated with the interconnection points 41 and 42.SELECTED DRAWING: Figure 1C

Description

[Technical field]

[0001] The present disclosure relates to a reduced model creation system and the like. [Background technology]

[0002] As a technology for reducing the load when calculating the control amount in a power system, for example, the technology described in Patent Document 1 is known. That is, Patent Document 1 describes that "a transmission system evaluation value, which is an evaluation value of the state of the power transmission system and includes the reduced power amount candidate, is used as an objective function to calculate a reduced power amount that is a sum of the active power amount and the reactive power amount of the reduced power distribution system so as to satisfy the reduced control power amount range." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7040693 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology described in Patent Document 1 is configured such that one distribution system is connected to a transmission system via an interconnection point. In Patent Document 1, if a first distribution system is connected to the transmission system via an interconnection point and a second distribution system is connected via another interconnection point, it may be difficult to deal with the situation for the following reason. That is, if the conditions at one interconnection point change, the effect will extend to the other interconnection point, and the transmission system evaluation value and the distribution system evaluation value will also change, which may complicate the processing when performing power flow calculation.

[0005] Therefore, an object of the present disclosure is to provide a reduced model creation system etc. that can also accommodate cases where multiple external systems are connected to a power system. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the reduced model creation system according to the present disclosure includes a processing unit that reduces an external system model, which is a model of each of a plurality of external systems, to create an external system reduced model, and the plurality of external systems are each connected to a predetermined power system via an interconnection point, and the processing unit displays, as the external system reduced model, information including a constraint condition indicating a controllable range of a predetermined electrical physical quantity of the external system at the interconnection point and an objective function with the electrical physical quantity as a variable, in association with the interconnection point on a display device. Effect of the Invention

[0007] According to the present disclosure, it is possible to provide a reduced model creation system etc. that can also accommodate cases where a plurality of external systems are connected to a power system. [Brief description of the drawings]

[0008] [Figure 1A] FIG. 2 is an explanatory diagram of an electric power system including a main system and an external system in the reduced model creation system according to the first embodiment. [Figure 1B] FIG. 2 is an explanatory diagram of a schematic system model including an external system model before reduction in the reduced model creation system according to the first embodiment. [Figure 1C] FIG. 2 is an explanatory diagram of a schematic system model including an external system reduced model in the reduced model creation system according to the first embodiment. [Diagram 2] FIG. 1 is a functional block diagram showing a configuration of a reduced model creation system according to a first embodiment. [Diagram 3] 4 is a flowchart of processing executed by a processing unit of the reduced model creation system according to the first embodiment. [Figure 4] 4 is a flowchart of a process related to creation of a controllable range in the reduced model creation system according to the first embodiment. [Diagram 5] FIG. 2 is an explanatory diagram regarding creation of a controllable range in the reduced model creation system according to the first embodiment. [Figure 6]4 is a flowchart of a process related to calculation of an evaluation value in the reduced model creation system according to the first embodiment. [Figure 7] FIG. 2 is an explanatory diagram regarding calculation of an evaluation value in the reduced model creation system according to the first embodiment. [Figure 8] 4 is a flowchart of a process related to creation of an objective function in the reduced model creation system according to the first embodiment. [Figure 9A] FIG. 2 is an explanatory diagram of an objective function in which active power is a variable in the reduced model creation system according to the first embodiment. [Figure 9B] FIG. 2 is an explanatory diagram of an objective function in which reactive power is a variable in the reduced model creation system according to the first embodiment. [Figure 10A] 4 is a display example including an external system model before reduction in the reduced model creating system according to the first embodiment. [Figure 10B] 1 is a display example including an external system reduced model of the reduced model creation system according to the first embodiment. [Figure 11] 10 is a flowchart of a process related to creation of a controllable range in the reduced model creation system according to the second embodiment. [Figure 12A] 13 is a flowchart of a process relating to creation of a controllable range in the reduced model creation system according to the third embodiment. [Figure 12B] 13 is a flowchart of a process relating to creation of a controllable range in the reduced model creation system according to the third embodiment. [Figure 13] FIG. 13 is an explanatory diagram regarding creation of a controllable range in the reduced model creation system according to the third embodiment. [Figure 14] 13 is a flowchart of a process related to creation of an objective function in the reduced model creation system according to the fourth embodiment. [Figure 15A] FIG. 13 is an explanatory diagram of an objective function in which active power is a variable in the reduced model creation system according to the fourth embodiment. [Figure 15B] FIG. 13 is an explanatory diagram of an objective function in which reactive power is a variable in the reduced model creation system according to the fourth embodiment. [Figure 16] FIG. 13 is a functional block diagram including a control amount determination system according to a fifth embodiment. [Figure 17] FIG. 13 is a functional block diagram including a control amount determination system according to a sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] First Embodiment In the following, we will first briefly explain the main system model 20 (see FIG. 1B) in which the main system 20W (see FIG. 1A) is modeled, and the external system models 31, 32 (see FIG. 1B) in which the external systems 31W, 32W (see FIG. 1A) are modeled, and then we will explain in detail the reduced model creation system 10 (see FIG. 2).

[0010] FIG. 1A is an explanatory diagram of a power system W1 including a main system 20W and external systems 31W and 32W in a reduced model creation system according to a first embodiment. The power system W1 shown in Fig. 1A is a system that supplies power generated by a power generation facility (not shown) to consumers (not shown) via transmission lines and distribution lines. In the example of Fig. 1A, the power system W1 is configured to include a main system 20W and external systems 31W and 32W.

[0011] The main system 20W (predetermined power system) is a power system that is a target when the control amount of the control device is calculated. For example, a power transmission system in a predetermined area managed by a power transmission company may be set as the main system 20W, or another predetermined power system may be set as the main system 20W. The external system 31W is a power system connected to the main system 20W via an interconnection point 41W. The other external system 32W is a power system connected to the main system 20W via another interconnection point 42W. For example, a power distribution system in a predetermined area managed by a power distribution company may be set as the external systems 31W and 32W, or another predetermined system may be set as the external systems 31W and 32W. FIG. 1A shows a configuration in which two external systems 31W and 32W are connected to the main system 20W as an example, but the number of external systems connected to the main system 20W may be three or more.

[0012] The main system 20W and the external systems 31W and 32W each include control devices (not shown) such as a power generation facility, a transformer, a phase modifying facility, and a switchgear, as well as power lines such as a transmission line and a distribution line, and load devices (not shown). The external systems 31W and 32W may be located downstream of the main system 20W, or may be located upstream of the main system 20W.

[0013] The interconnection point 41W is an electrical connection point between the main system 20W and the external system 31W. Another interconnection point 42W is an electrical connection point between the main system 20W and the other external system 32W. In this manner, the multiple external systems 31W, 32W are connected to the main system 20W (a predetermined power system) via the interconnection points 41W, 42W, respectively. These interconnection points 41W, 42W may be, for example, a transformer (not shown), or may be other equipment such as a switch (not shown).

[0014] FIG. 1B is an explanatory diagram of a schematic system model M1 including pre-reduced external system models 31 and 32. The system model M1 shown in Fig. 1B is a predetermined model of a power system W1 (see Fig. 1A) including a main system 20W (see Fig. 1A) and external systems 31W and 32W (see Fig. 1A). As shown in Fig. 1B, the system model M1 is configured to include a main system model 20, external system models 31 and 32, and interconnection points 41 and 42.

[0015] The main system model 20 is a predetermined model of the main system 20W (see FIG. 1A). The external system model 31 is a predetermined model of the external system 31W (see FIG. 1A). The other external system model 32 is a predetermined model of the external system 32W (see FIG. 1A). These main system model 20 and the external system models 31 and 32 are each configured as a power network including a plurality of nodes (nodes) and a plurality of links (branches) connecting the nodes. The interconnection point 41 is a connection point between the main system model 20 and the external system model 31, and corresponds to the interconnection point 41W in FIG. 1A. The other interconnection point 42 is a connection point between the main system model 20 and the external system model 32, and corresponds to the interconnection point 42W in FIG. 1A.

[0016] For example, when calculating the control amount of a control device (not shown) for the entire system model M1, the larger the scale of the system model M1, the larger the calculation amount becomes, and the longer the calculation time becomes. Therefore, in the first embodiment, a reduced model creation system 10 (see FIG. 2) described later reduces the external system models 31, 32 (see FIG. 1B) to create external system reduced models 31a, 32a (see FIG. 1C). Here, "reduction" means reducing the scale and simplifying. In this way, by creating the external system reduced models 31a, 32a (see FIG. 1C), the amount of calculation required to calculate the control amount of the control device (not shown) of the main system model 20 is reduced, and the calculation time can be significantly shortened.

[0017] FIG. 1C is an explanatory diagram of a schematic system model M2 including external system contraction models 31a and 32a. The external system contraction model 31a shown in Fig. 1C is a contracted model of the external system model 31 (see Fig. 1B), and is represented by a predetermined constraint condition and an objective function at a grid-connection point 41. The other external system contraction model 32a is a contracted model of the external system model 32 (see Fig. 1B), and is represented by a predetermined constraint condition and an objective function at a grid-connection point 42. In this way, one of the main features of the first embodiment is that the external system contraction models 31a and 32a are represented by the constraint condition and the objective function.

[0018] The "control conditions" are conditions that indicate the possible ranges of certain variables (electrical physical quantities) such as active power P, reactive power Q, and voltage V. The "objective function" is a certain function whose value is maximized or minimized in the power flow calculation.

[0019] The constraint condition of the external system contraction model 31a is expressed by the range of the electrical physical quantity at the interconnection point 41W (see FIG. 1A) for making the external system 31W (see FIG. 1A) controllable. The same applies to the constraint condition of the other external system contraction model 32a. Such a range of the electrical physical quantity is called a "controllable range." In the first embodiment, a case will be described in which active power P, reactive power Q, and voltage V are used as the electrical physical quantity, but the present invention is not limited to this. For example, other electrical physical quantities such as current I and phase angle θ may be used. In addition to the average value of the electrical physical quantity per unit time, an integrated value or instantaneous value of the electrical physical quantity may be used.

[0020] In the example of FIG. 1C, as shown in the following equations (1) to (3), the effective power P a , reactive power Q a , and voltage V a The controllable ranges of the other external system reduction model 32a are set in the same manner.

[0021] P a下限 ≦P a ≦P a上限 (1) Q a下限 ≦Q a ≦Q a上限 (2) V a下限 ≦V a ≦V a上限 (3)

[0022] The objective function of the external system contraction model 31a is expressed by a function with a predetermined electrical physical quantity of the external system 31W (see FIG. 1A) at the interconnection point 41W (see FIG. 1A) as a variable. As such an objective function, a function indicating a physical cost such as fuel cost and power transmission loss, as well as a monetary cost such as a power procurement cost, an adjustment capability procurement cost, a demand response request cost, and a renewable energy output suppression cost may be used. In addition, as the objective function, a predetermined function related to stability and safety such as a margin for a specified voltage value, a capacity factor (e.g., transmitted power relative to a power transmission capacity), and a control margin for a control device may be used.

[0023] In addition, a function including a penalty when the voltage deviates from a specified value, a penalty when the capacity factor exceeds a specified value, a penalty when a reverse power flow occurs, etc. may be used as the objective function. In addition, a plurality of functions may be used as the objective function of the external system reduction model 31a. In the example of FIG. 1C, as shown in the following equation (4), the active power P a Function f including the reactive power Q a The objective function of the external system reduction model 31a is expressed by the sum of a function g including the above function and the above function. The same is true for the objective function of the other external system reduction model 32a.

[0024] f a (P a )+g a (Q a ) ···(4)

[0025] The objective functions of the external system reduction models 31a and 32a are not limited to the form of equation (4) and may be expressed by a predetermined function h including active power P, reactive power Q, and voltage V, for example, as in the following equation (5).

[0026] h(P,Q,V) (5)

[0027] FIG. 2 is a functional block diagram showing the configuration of the reduced model creation system 10. As shown in FIG. The reduced model creation system 10 shown in Fig. 2 is a system that reduces external system models 31, 32 (see Fig. 1B) to create external system reduced models 31a, 32a (see Fig. 1C). As shown in Fig. 2, the reduced model creation system 10 includes a storage unit 11 and a processing unit 12. Although not shown, the storage unit 11 includes a non-volatile memory such as a Read Only Memory (ROM) and a volatile memory such as a Random Access Memory (RAM) and a register. In addition to storing predetermined programs and parameters in advance, the storage unit 11 also stores data acquired via an information input unit 121 and predetermined calculation results.

[0028] The processing unit 12 is, for example, a CPU (Central Processing Unit), and reads and develops a program stored in the storage unit 11 to execute a predetermined process. That is, the processing unit 12 reduces external system models 31, 32 (see FIG. 1B), which are models of a plurality of external systems 31W, 32W (see FIG. 1A), to create external system reduced models 31a, 32a (see FIG. 1C). As shown in FIG. 2, the processing unit 12 includes an information input unit 121, a controllable range creation unit 122, an evaluation value calculation unit 123, an objective function creation unit 124, and a reduced model output unit 125.

[0029] The information input unit 121 is an interface for inputting information on the external system models 31, 32 (see FIG. 1B) from the outside, and is connected to the input device 51. The input device 51 is, for example, a keyboard, a mouse, or a mobile terminal. In this way, the information on the external system models 31, 32 (see FIG. 1B) may be input by an operation via the input device 51, but is not limited to this. For example, information may be acquired from a predetermined database (not shown) via the information input unit 121. Also, information may be collected via the information input unit 121 from measuring instruments (not shown) and control devices (not shown) installed in the external systems 31W, 32W (see FIG. 1A).

[0030] The controllable range creation unit 122 creates a controllable range of a predetermined electrical physical quantity based on information of the external system models 31, 32 (see FIG. 1B) input via the information input unit 121. The electrical physical quantity is the active power, reactive power, and voltage of the external systems 31W, 32W (see FIG. 1A) at the interconnection points 41W, 42W (see FIG. 1A).

[0031] The evaluation value calculation unit 123 calculates a predetermined evaluation value for each of a plurality of conditions having different magnitudes of electrical physical quantities, based on information of the external system models 31, 32 (see FIG. 1B) input via the information input unit 121 and the controllable range created by the controllable range creation unit 122. Here, the "evaluation value" refers to physical costs such as fuel costs and power transmission losses, and monetary costs, and corresponds to the value of the objective function described above.

[0032] Based on the calculation result of the evaluation value calculation unit 123, the objective function creation unit 124 creates an objective function that uses a predetermined electrical physical quantity as a variable. The reduced model output unit 125 creates external system reduced models 31a, 32a (see FIG. 1C) by associating the controllable range created by the controllable range creation unit 122 and the objective function created by the objective function creation unit 124 with the interconnection points 41, 42 (see FIG. 1C). Then, the reduced model output unit 125 causes information including the external system reduced models 31a, 32a to be displayed in a predetermined manner on the display device 52. The display device 52 is a display on which predetermined information is displayed.

[0033] FIG. 3 is a flowchart of the process executed by the processing unit of the reduced model creating system (also see FIG. 2 as appropriate). In step S1, the processing unit 12 acquires, via the information input unit 121, information on the external system models 31 and 32 (see FIG. 1B). In step S2, the processing unit 12 causes the controllable range creation unit 122 to create a controllable range of a predetermined electrical physical quantity at the interconnection points 41 and 42 (see FIG. 1B). In step S3, the processing unit 12 causes the evaluation value calculation unit 123 to calculate predetermined evaluation values ​​at the interconnection points 41 and 42 (see FIG. 1B) under each of a plurality of conditions. In step S4, the processing unit 12 causes the objective function creation unit 124 to create an objective function that uses predetermined electrical physical quantities as variables.

[0034] The "reduced model creation process" for creating the external system reduced models 31a, 32a by reducing the external system models 31, 32 (see FIG. 1B), which are models of the multiple external systems 31W, 32W (see FIG. 1A), includes steps S2 to S4 in FIG. 3. In this "reduced model creation process", information including constraint conditions indicating controllable ranges of predetermined electrical physical quantities (active power, reactive power, and voltage) of the external systems 31W, 32W (see FIG. 1) at the interconnection points 41W, 42W (see FIG. 1A) and objective functions with the electrical physical quantities as variables is created as the external system reduced models 31a, 32a (see FIG. 1C).

[0035] In step S5, the processing unit 12 outputs the external system contraction models 31a, 32a (see FIG. 1C), which are information in which the controllable range and the objective function are associated with the interconnection points 41, 42 (see FIG. 1C), to the display device 52 by the contraction model output unit 125. Note that the "display process" of displaying the external system contraction models 31a, 32a on the display device 52 in association with the interconnection points 41, 42 includes step S5. After performing the process of step S5, the processing unit 12 ends the series of processes (END).

[0036] Next, steps S2, S3, and S4 in Fig. 3 will be described in order. In the following, the case where the external system reduction model 31a (see Fig. 1C) is created will be mainly described, but the other external system reduction model 31b (see Fig. 1C) is also created in the same manner.

[0037] FIG. 4 is a flowchart of a process for creating a controllable range (also see FIG. 2 as appropriate). The details of the process of step S2 (see FIG. 3) are shown in FIG. 4. At the time of "START" in FIG. 4, information on the external system models 31 and 32 (see FIG. 1B) is assumed to be stored in the storage unit 11. In step S201, the processing unit 12 calculates the active power P31 and the reactive power Q31 when the value of (active power P+reactive power Q) of the external system model 31 (see FIG. 1B) is maximized at the interconnection point 41 (see FIG. 1B). For example, the processing unit 12 may execute an optimal power flow calculation with the (active power P+reactive power Q) of the external system model 31 as an objective function at the interconnection point 41. Also, the processing unit 12 may perform a predetermined power flow calculation after setting a control amount of a control device (not shown) of the external system model 31 so that the (active power P+reactive power Q) of the external system model 31 is maximized at the interconnection point 41. Next, the active power P31 and the reactive power Q31 calculated in step S201 will be described with reference to FIG. 5.

[0038] FIG. 5 is an explanatory diagram regarding the creation of the controllable range. The horizontal axis of Fig. 5 is the reactive power Q of the external system model 31 (see Fig. 1B) at the interconnection point 41 (see Fig. 1B). The vertical axis of Fig. 5 is the active power P of the external system model 31 at the interconnection point 41. The region inside the elliptical dashed line R shown in Fig. 5 indicates the range that the active power P and reactive power Q of the external system model 31 can actually take at the interconnection point 41. Below, creation of the controllable range at the interconnection point 41 will be described, but the same applies to the controllable range at the other interconnection point 42 (see Fig. 1B).

[0039] The active power P31 and reactive power Q31 calculated in step S201 correspond to point A where the value of (active power P + reactive power Q) is maximum. Note that the coordinates (P31, Q31) of point A are written in parentheses such that the value of active power P on the vertical axis is written first and the value of reactive power Q on the horizontal axis is written afterwards (the same applies to other points B, C, D, etc.).

[0040] Next, in step S202 in Fig. 4, the processing unit 12 calculates the active power P32 and the reactive power Q32 when the value of (active power P-reactive power Q) of the external system model 31 (see Fig. 1B) becomes maximum at the interconnection point 41 (see Fig. 1B). Note that the active power P32 and the reactive power Q32 correspond to point B (see Fig. 5) where the value of (active power P-reactive power Q) becomes maximum.

[0041] Next, in step S203 in Fig. 4, the processing unit 12 calculates the active power P33 and the reactive power Q33 when the value of (-active power P + reactive power Q) of the external system model 31 (see Fig. 1B) becomes maximum at the interconnection point 41 (see Fig. 1B). Note that the active power P33 and the reactive power Q33 correspond to point C (see Fig. 5) where the value of (-active power P + reactive power Q) becomes maximum.

[0042] Next, in step S204 in Fig. 4, the processing unit 12 calculates the active power P34 and the reactive power Q34 when the value of (-active power P-reactive power Q) of the external system model 31 (see Fig. 1B) becomes maximum at the interconnection point 41 (see Fig. 1B). Note that the active power P34 and the reactive power Q34 correspond to point D (see Fig. 5) where the value of (-active power P-reactive power Q) becomes maximum.

[0043] As described above, the elliptical dashed line R shown in Fig. 5 is the maximum area in which the external system 31W (see Fig. 1A) is controllable. In order to make the controllable range X1 as wide as possible within the inner area of ​​this dashed line R, the processing unit 12 performs the processes of steps S201 to S204 to identify points A, B, C, and D in Fig. 5. In the example of Fig. 5, points A, B, C, and D exist on the dashed line R. The order of the processes of steps S201 to S204 in Fig. 4 can be changed as appropriate. Also, the processes of steps S201 to S204 may be performed in parallel.

[0044] Next, in step S205 of FIG. 4, the processing unit 12 creates a controllable range of the active power P and the reactive power Q. Specifically, the processing unit 12 sets the smaller value of the active power P31 calculated in step S201 and the active power P32 calculated in step S202 as the upper limit value of the active power P of the external power system 31W (see FIG. 1A) at the connection point 41W (see FIG. 1A). In the example of FIG. 5, since the relationship is P31 > P32, the value of the active power P32 is set as the upper limit value of the active power P.

[0045] If, instead of the smaller active power P32, the larger active power P31 is set as the upper limit value, when setting the rectangular controllable range X1, the corner of this controllable range X1 (for example, the corner near point B) may fall outside the range of the broken line R. Therefore, the smaller of the active powers P31 and P32 in terms of magnitude is set as the upper limit value of the active power P. When the values of the active powers P31 and P32 are the same, that value is set as the upper limit value of the active power P.

[0046] Similarly, as the processing in step S205, the processing unit 12 sets the larger value of the active powers P33 and P34 in FIG. 5 as the lower limit value of the active power P of the external power system 31W (see FIG. 1A) at the connection point 41W (see FIG. 1A). In the example of FIG. 5, since the relationship is P33 > P34, the value of the active power P34 is set as the lower limit value of the active power P.

[0047] Also, the processing unit 12 sets the smaller value of the reactive powers Q31 and Q33 in FIG. 5 as the upper limit value of the reactive power Q of the external power system 31W (see FIG. 1A) at the connection point 41W (see FIG. 1A). In the example of FIG. 5, since the relationship is Q31 < Q33, the value of the reactive power Q31 is set as the upper limit value of the reactive power Q. Also, the processing unit 12 sets the larger value of the reactive powers Q32 and Q34 in FIG. 5 as the lower limit value of the reactive power Q of the external power system 31W (see FIG. 1A) at the connection point 41W (see FIG. 1A). In the example of FIG. 5, since the relationship is Q32 < Q34, the value of the reactive power Q34 is set as the lower limit value of the reactive power Q.

[0048] Then, the processing unit 12 sets a range specified by the upper and lower limits of the active power P and the upper and lower limits of the reactive power Q as a controllable range X1. In the example of Fig. 5, a rectangular controllable range X1 is set inside an elliptical dashed line R. Similarly, a controllable range is also set for the active power P and reactive power Q of the external system 32W (see Fig. 1A) at the other interconnection point 42W (see Fig. 1A).

[0049] FIG. 6 is a flowchart of a process relating to calculation of an evaluation value (also see FIG. 2 as appropriate). The details of the process of step S3 (see FIG. 3) are shown in FIG. 6. At the time of "START" in FIG. 6, the controllable ranges of the active power P and reactive power Q at each of the interconnection points 41W and 42W (see FIG. 1A) are set, and the data of the controllable ranges is stored in the storage unit 11.

[0050] In step S301, the processing unit 12 calculates an evaluation value under conditions of predetermined reference active power P40 and reactive power Q40 at the interconnection point 41 (see FIG. 1B). As a specific example of step S301, the processing unit 12 performs an optimal power flow calculation using the external system model 31 (see FIG. 1B) so as to maximize (e.g., maximize efficiency) or minimize (e.g., minimize cost) the predetermined evaluation value. Then, the processing unit 12 sets the values ​​of the active power P and reactive power Q of the external system model 31 (see FIG. 1B) at the interconnection point 41 (see FIG. 1B) when the optimal power flow calculation is performed as the reference active power P40 and reactive power Q40.

[0051] In the actual operation of the external system 31W (see FIG. 1A), the active power P and reactive power Q at the interconnection point 41W (see FIG. 1A) are likely to be close to the values ​​of the active power P40 and reactive power Q40 based on the optimal power flow calculation. Therefore, the processing unit 12 calculates evaluation values ​​under each of a plurality of conditions based on the active power P40 and reactive power Q40 (S302 to S306). Note that the values ​​of the active power P and reactive power Q at the interconnection point 41W (see FIG. 1A) when the most recent control amount (or the expected control amount) of the control device (not shown) of the external system 31W (see FIG. 1A) is used may be used as the active power P40 and reactive power Q40 in step S301.

[0052] FIG. 7 is an explanatory diagram regarding calculation of the evaluation value. It is assumed that the controllable range X1 shown in FIG. 7 is the same as that shown in FIG. In Fig. 7, a reference point E specified by active power P40 and reactive power Q40 exists inside a rectangular controllable range X1. The values ​​of active power P40 and reactive power Q40 at the reference point E are used in the processing of steps S302 to S305 (see Fig. 6), as will be described next.

[0053] In step S302 in Fig. 6, the processing unit 12 calculates an evaluation value under the conditions of the upper limit value of active power P at the interconnection point 41 (see Fig. 1B) and reference reactive power Q40 based on the external system model 31 (see Fig. 1B). The upper limit value of active power P is specified based on the controllable range X1 (see Fig. 7) created in step S205 in Fig. 4. In the example in Fig. 7, the evaluation value is calculated at point F, which is the intersection point between the dashed line L1 in the P-axis direction passing through the reference point E and the upper side of the rectangular controllable range X1.

[0054] In step S303 in Fig. 6, the processing unit 12 calculates an evaluation value under the conditions of the lower limit value of active power P at the interconnection point 41 (see Fig. 1B) and reference reactive power Q40 based on the external system model 31 (see Fig. 1B). The lower limit value of active power P is specified based on the controllable range X1 (see Fig. 7). In the example of Fig. 7, the evaluation value is calculated at point G, which is the intersection point of dashed line L1 in the P-axis direction passing through reference point E and the lower side of the rectangular controllable range X1.

[0055] In step S304 in Fig. 6, the processing unit 12 calculates an evaluation value based on the external system model 31 (see Fig. 1B) under the conditions of the reference active power P40 at the interconnection point 41 (see Fig. 1B) and the upper limit value of the reactive power Q. The upper limit value of the reactive power Q is specified based on the controllable range X1 (see Fig. 7). In the example in Fig. 7, the evaluation value is calculated at point H, which is the intersection point of the dashed line L2 in the Q-axis direction passing through the reference point E and the right side of the rectangular controllable range X1.

[0056] In step S305 in Fig. 6, the processing unit 12 calculates an evaluation value based on the external system model 31 (see Fig. 1B) under the conditions of the reference active power P40 at the interconnection point 41 (see Fig. 1B) and the lower limit value of the reactive power Q. The lower limit value of the reactive power Q is specified based on the controllable range X1 (see Fig. 7). In the example of Fig. 7, the evaluation value is calculated at point K, which is the intersection point of the dashed line L2 in the Q-axis direction passing through the reference point E and the left side of the rectangular controllable range X1.

[0057] The order of steps S302 to S305 in Fig. 6 can be changed as appropriate. Steps S302 to S305 may be performed in parallel. In this manner, for the interconnection point 41 (see Fig. 1B), evaluation values ​​are calculated for the reference point E shown in Fig. 7 as well as for the four points F, G, H, and K. Similarly, evaluation values ​​are calculated for the other interconnection point 42 (see Fig. 1B) for each of a plurality of conditions.

[0058] FIG. 8 is a flowchart of a process for creating an objective function (also see FIG. 2 as appropriate). The details of the process of step S4 (see FIG. 3) are shown in FIG. 8. At the time of "START" in FIG. 8, the controllable ranges of active power P and reactive power Q, as well as data on each evaluation value at reference point E (see FIG. 7) and points F, G, H, and K (see FIG. 7) are stored in the storage unit 11.

[0059] In step S401, the processing unit 12 creates an objective function with the active power P as a variable, based on the reactive power Q at the interconnection point 41 (see FIG. 1B) and the evaluation values ​​of the active power P under multiple conditions. Focusing on the relationship between the active power P and the evaluation value, evaluation values ​​when the active power P is at the upper limit (point F) and the lower limit (point G) are calculated in addition to the evaluation value at the reference point E shown in FIG. 7. Based on the active power P and the evaluation values ​​at each of these reference point E and points F and G, an objective function with the active power P as a variable is derived.

[0060] FIG. 9A is an explanatory diagram of an objective function with active power P as a variable. In Fig. 9A, the horizontal axis represents active power P, and the vertical axis represents a predetermined evaluation value. Point Ec1 shown in Fig. 9A is a point specified by active power P40 of reference point E (see Fig. 7) and the evaluation value. Point Fc1 is a point specified by active power P32 of the upper limit (point F in Fig. 5) and the evaluation value. Point Gc1 is a point specified by active power P33 of the lower limit (point G in Fig. 5) and the evaluation value.

[0061] Based on the effective power P and the evaluation value of each of the points Ec1, Fc1, and Gc1 shown in Fig. 9A, an objective function with the effective power P as a variable is approximately derived as shown in the following formula (6). As a method for approximately deriving the objective function, for example, the least squares method is used. Note that a4 and b4 included in formula (6) are predetermined values.

[0062] a4 × (active power P) + b4 (6)

[0063] 9A shows, as an objective function, a straight line L3 of a linear function (equation (6)) with the effective power P as a variable. Note that the objective function does not necessarily have to be a linear function, and may be a quadratic function or another predetermined function.

[0064] Next, in step S402 in Fig. 8, the processing unit 12 creates another objective function with reactive power Q as a variable, based on the active power P at the interconnection point 41 (see Fig. 1B) and the evaluation values ​​for reactive power Q under multiple conditions. Focusing on the relationship between reactive power Q and the evaluation value, evaluation values ​​when reactive power Q is at its upper limit (point H) and lower limit (point K) are calculated in addition to the evaluation value at reference point E shown in Fig. 7. Based on the reactive power Q and the evaluation values ​​at each of these reference point E and points H and K, an objective function with reactive power Q as a variable is derived.

[0065] FIG. 9B is an explanatory diagram of an objective function with reactive power Q as a variable. In addition, the horizontal axis of Fig. 9B is reactive power Q, and the vertical axis is a predetermined evaluation value. Point Ec2 shown in Fig. 9B is a point specified by reactive power Q40 of reference point E (see Fig. 7) and the evaluation value. Point Hc2 is a point specified by upper limit reactive power Q31 (point H in Fig. 5) and the evaluation value. Point Kc1 is a point specified by lower limit reactive power Q34 (point K in Fig. 5) and the evaluation value.

[0066] Based on the reactive power Q and the evaluation values ​​of the points Ec2, Hc2, and Kc2 shown in Fig. 9B, an objective function with the reactive power Q as a variable is approximately derived as shown in the following formula (7). Note that a5 and b5 included in formula (6) are predetermined values.

[0067] a5 × (reactive power Q) + b5 (7)

[0068] 9B shows, as an objective function, a straight line L4 of a linear function (equation (7)) with reactive power Q as a variable. In this manner, the processing unit 12 creates, for each of the interconnection points 41 and 42 (see FIG. 1B), an objective function with active power P as a variable (S401 in FIG. 8) and another objective function with reactive power Q as a variable (S402 in FIG. 8).

[0069] That is, the processing unit 12 calculates a predetermined evaluation value under each of a plurality of conditions (reference point E and points F, G, H, and K: see FIG. 7) in which the values ​​of electrical physical quantities (active power P and reactive power Q) are different in the controllable range X1 (see FIG. 7), and creates an objective function based on the electrical physical quantities and evaluation values ​​corresponding to the plurality of conditions. The above-mentioned plurality of conditions includes one in which the evaluation value is maximum or minimum in the controllable range X1 (reference point E in FIG. 7). This makes it possible to create a predetermined objective function based on the active power P and reactive power Q when the external systems 31W and 32W (see FIG. 1A) are operated so as to obtain the optimal evaluation value. Therefore, it is possible to reduce the error of the objective function.

[0070] The order of the processes in steps S401 and S402 in Fig. 8 can be changed as appropriate. The processes in steps S401 and S402 may be performed in parallel. Alternatively, for example, as shown in the following formula (8), an objective function with active power P and reactive power Q as variables may be derived based on evaluation values ​​under multiple conditions (i.e., multiple points). Note that a6, b6, c6, d6, and e6 included in formula (8) are each a predetermined value.

[0071] a6 × (effective power P) 2 + b6 × (active power P) + c6 × (reactive power Q) 2 +d6×(reactive power Q)+e6...Equation (8)

[0072] Furthermore, the objective function does not necessarily have to be expressed as a linear or quadratic expression, and may be expressed as a cubic expression or in another predetermined format. Next, a display example of the process of step S5 in FIG.

[0073] FIG. 10A is a display example including external system models 31 and 32 before reduction. In the example of Fig. 10A, the connection relationships of the components of the main system model 20 are displayed on the display device 52 (see Fig. 2), as well as the connection relationships of the components of the external system models 31 and 32. Although the interconnection points 41 and 42 are shown by lines, they may be displayed by predetermined marks such as circles or stars. Furthermore, the identification numbers of the interconnection points 41 and 42 may be displayed.

[0074] FIG. 10B is a display example including external system reduced models 31a and 32a. In the example of Fig. 10B, predetermined constraint conditions and objective functions are displayed as the external system contraction model 31a in a portion surrounded by a balloon at the interconnection point 41. The same is true for the external system contraction model 32a at the interconnection point 42. In this manner, the processing unit 12 causes the display device 52 (see Fig. 2) to display information including constraint conditions indicating controllable ranges of predetermined electrical physical quantities (active power, reactive power, and voltage) of the external systems 31W and 32W (see Fig. 1A) at the interconnection points 41 and 42 and an objective function using the electrical physical quantities as variables as the external system contraction models 31a and 32a in association with the interconnection points 41 and 42.

[0075] This allows the user to grasp the specific contents of each of the external system contraction models 31a and 32a at a glance. The display screen of Fig. 10A and the display screen of Fig. 10B may be switched by selecting a tab or the like (not shown) on the display screen. This makes it easier for the user to grasp the states of the external system models 31 and 32 before and after contraction.

[0076] In addition, data of the external system contraction models 31a, 32a may be provided to a business operator who manages the main system 20W (see FIG. 1A) or to another business operator who is entrusted with the calculation of the control amount by the business operator. The control amount of a control device (not shown) of the main system 20W is calculated by a well-known method based on predetermined constraint conditions and objective functions in the main system 20W and constraint conditions and objective functions included in the external system contraction models 31a, 32a.

[0077] <Effects> According to the first embodiment, an external system contraction model 31a is associated with a node of an interconnection point 41 (see FIG. 1C), and an external system contraction model 32a is associated with a node of another interconnection point 42 (see FIG. 1C). Each of the external system contraction models 31a and 32a includes a constraint condition expressed by a predetermined controllable range and an objective function.

[0078] As a result, for example, when the processing unit 12 calculates the control amount of the control device of the main system 20W (see FIG. 1A), it is sufficient to perform the optimal power flow calculation after adding the constraint conditions and objective functions of the external system contraction models 31a, 32a to the predetermined constraint conditions and objective functions of the main system model 20, and therefore the processing can be simplified. In this way, according to the first embodiment, it is possible to appropriately handle the case where a plurality of external systems 31W, 32W (see FIG. 1A) are connected to the main system 20W (predetermined power system). In addition, since the amount of calculation required for the optimal power flow calculation is smaller than when the external system models 31, 32 before contraction are used, the calculation time can be significantly shortened.

[0079] Second Embodiment The second embodiment differs from the first embodiment in that when the controllable range is created, the active power P and the reactive power Q are multiplied by a predetermined weighting coefficient. Note that the configuration of the reduced model creation system 10 (see FIG. 2) and the processes other than the setting of the controllable range (see FIG. 3, FIG. 6 to FIG. 9A, FIG. 9B) are the same as those in the first embodiment. Therefore, only the parts that differ from the first embodiment will be described, and a description of the overlapping parts will be omitted.

[0080] FIG. 11 is a flowchart of a process relating to creation of a controllable range in the reduced model creation system according to the second embodiment (also see FIG. 2 as appropriate). The series of processes shown in FIG. 11 corresponds to step S2 in FIG. In step S201a, the processing unit 12 calculates the active power P61 and the reactive power Q61 when the value of (α×active power P+β×reactive power Q) of the external system model 31 (see FIG. 1B) becomes maximum at the interconnection point 41 (see FIG. 1B). Note that α and β are predetermined weighting coefficients, and are set by the user through an operation via the input device 51 (see FIG. 2).

[0081] For example, when reactive power Q has a higher influence on the evaluation value than active power P, weighting factor β of reactive power Q is set to a larger value than weighting factor α of active power P. It is assumed that the user has a prior understanding of the above-mentioned influence (i.e., the magnitude relationship between weighting factors α and β) based on a qualitative judgment or a predetermined simulation result. As a specific example, when transmission loss is used as the evaluation value, when reactive power Q has a higher influence on the reduction of transmission loss than active power P, weighting factor β is set to a larger value than weighting factor α. In this way, it becomes possible to set a larger controllable range for a variable that has a higher influence on the evaluation value, and the user's freedom in setting the controllable range is increased.

[0082] Next, in step S202a, the processing unit 12 calculates the active power P62 and the reactive power Q62 when the value of (α×active power P−β×reactive power Q) of the external system model 31 (see FIG. 1B) at the interconnection point 41 (see FIG. 1B) is maximized. In step S203a, the processing unit 12 calculates the active power P63 and the reactive power Q63 when the value of (-α×active power P+β×reactive power Q) of the external system model 31 (see FIG. 1B) at the interconnection point 41 (see FIG. 1B) is maximized.

[0083] In step S204a, the processing unit 12 calculates the active power P64 and the reactive power Q64 when the value of (-α×active power P-β×reactive power Q) of the external system model 31 (see FIG. 1B) at the interconnection point 41 (see FIG. 1B) is maximized. In this way, when creating a controllable range based on a predetermined formula (the formulas of S201a to S204a) including the active power P and reactive power Q of the external system model 31 at the interconnection point 41, the processing unit 12 multiplies each of the active power P and reactive power Q included in this formula by the predetermined weighting coefficients α and β.

[0084] Next, in step S205a, the processing unit 12 creates the controllable ranges of the active power P and the reactive power Q. The controllable ranges of the active power P and the reactive power Q at the other interconnection point 42 (see FIG. 1B) are created in the same manner. The creation of the controllable range is similar to the process of step S205 (see FIG. 4) described in the first embodiment, and therefore will not be described.

[0085] <Effects> According to the second embodiment, the user can set the controllable range of the electrical physical quantity that has a large influence on the evaluation value in the external system models 31 and 32 (see FIG. 1B) to a larger value. Therefore, each objective function can be appropriately set based on information including a relatively high evaluation value.

[0086] Third Embodiment The third embodiment differs from the first embodiment in that the controllable range is set so as to include the active power P and reactive power Q when the evaluation value is optimized. Note that the configuration of the reduced model creation system 10 (see FIG. 2) and the processes other than the setting of the controllable range (see FIG. 3, FIG. 6 to FIG. 9A, FIG. 9B) are the same as those in the first embodiment. Therefore, only the parts that are different from the first embodiment will be described, and a description of the overlapping parts will be omitted.

[0087] 12A and 12B are flowcharts showing processes relating to the creation of a controllable range in the reduced model creation system according to the third embodiment (also see FIG. 2 as appropriate). 12A and 12B correspond to step S2 in Fig. 3. Moreover, the process of steps S201a to S204a shown in Fig. 12A is similar to the process of steps S201a to S204a (see Fig. 11) described in the second embodiment, and therefore description thereof will be omitted.

[0088] After performing the process of step S204a, in step S210, the processing unit 12 calculates the active power P71 and the reactive power Q71 at the interconnection point 41 (see FIG. 1B) when the process of optimizing the evaluation value of the external system model 31 (see FIG. 1B) is performed. That is, the processing unit 12 specifies the active power P and the reactive power Q at the interconnection point 41 (see FIG. 1B) when maximizing (for example, maximizing efficiency) or minimizing (for example, minimizing cost) the evaluation value.

[0089] Next, in step S211 in Fig. 12B, the processing unit 12 judges whether or not the active power P71 that optimizes the evaluation value is greater than either the active power P61 or the active power P62. Note that the active powers P61 and P62 are values ​​calculated in steps S201a and S202a in Fig. 12A. Here, the technical meaning of the process in step S211 will be explained with reference to Fig. 13.

[0090] FIG. 13 is an explanatory diagram regarding the creation of the controllable range X3. The horizontal axis in FIG. 13 is the reactive power Q of the external system model 31 (see FIG. 1B) at the interconnection point 41 (see FIG. 1B). The vertical axis in FIG. 13 is the active power P of the external system model 31 at the interconnection point 41. The area inside the elliptical dashed line R indicates the range that the active power P and reactive power Q can actually take at the interconnection point 41. The controllable range X2 shown in FIG. 13 is a provisional controllable range identified by points A, B, C, and D based on the calculation results of steps S201a to S204a. The controllable range X3 shown in FIG. 13 is the controllable range that is finally set.

[0091] For example, the optimum point M (point specified by active power P71 and reactive power Q71) at which a predetermined evaluation value based on the external system model 31 (see FIG. 1B) is maximized or minimized may be present inside the controllable range X2, but in some cases may be present outside the controllable range X2. In the external system 31W (see FIG. 1A), control is often performed so that the evaluation value is optimized, so it is desirable that the optimum point M is included in the controllable range. Therefore, in the third embodiment, the processing unit 12 creates the controllable range X3 so as to include the optimum point M.

[0092] 12B, if the active power P71 is greater than either the active power P61 or the active power P62 (S211: Yes), the processing of the processing unit 12 proceeds to step S212. In other words, if the active power P71 is greater than the smaller of the active power P61 and the active power P62, the processing of the processing unit 12 proceeds to step S212. In step S212, the processing unit 12 performs an overwrite process of the active powers P61, P62 and the reactive powers Q61, Q62. That is, the processing unit 12 changes the values ​​of the active powers P61, P62 and the reactive powers Q61, Q62 so that the controllable range X3 (see FIG. 13) includes the optimal point M.

[0093] 13, the active power P71 of the optimal point M is greater than the active powers P61, P62 (S211: Yes). That is, the optimal point M (P71, Q71) is located on the positive side in the P-axis direction (upper side on the paper) of the provisional controllable range X2. In such a case, an overwrite process is performed on each of the active powers P61, P62 so that their magnitudes become equal to the value of the active power P71 of the optimal point M.

[0094] For the reactive power Q61, a process is performed in which the reactive power Q value when (α×active power P71+β×reactive power Q) is maximized is overwritten at the interconnection point 41 (see FIG. 1B) of the external system model 31 (see FIG. 1B). FIG. 13 shows a point Am identified by (P61m, Q61m) after the overwriting. For the other reactive power Q62, a process is performed in which the reactive power Q value when (α×active power P71-β×reactive power Q) is maximized is overwritten at the interconnection point 41 (see FIG. 1B) of the external system model 31 (see FIG. 1B). FIG. 13 shows a point Bm identified by (P62m, Q62m) after the overwriting process.

[0095] If the judgment condition in step S211 is satisfied, there is no need to change the positions of point C (P63, Q63) or point D (P64, Q64). This is because, even if the positions of points C and D are not changed, a rectangular controllable range X3 including points Cm and Dm in FIG. 13 is created in the process in the next step S213.

[0096] Next, in step S213 of Fig. 12B, the processing unit 12 creates a controllable range of the active power P and the reactive power Q. In the example of Fig. 13, the controllable range X3 is created based on the active power P and the reactive power Q of each of the points Am, Bm, C, and D. In this manner, the processing unit 12 creates the controllable range X3 so that the point (optimum point M in Fig. 13) indicating the condition when a predetermined evaluation value becomes maximum or minimum is included in the controllable range X3. Note that the process of creating the controllable range X3 based on the upper and lower limits of the active power P and the reactive power Q is similar to the process of step S205 of the first embodiment (see Figs. 4 and 5), and therefore a description thereof will be omitted.

[0097] 12B, if the active power P71 of the optimal point M is not greater than either the active power P61 or the active power P62 (S211: No), the processing of the processing unit 12 proceeds to step S214. In other words, if the active power P71 of the optimal point M is equal to or less than the active power P61 and equal to or less than the active power P62, the processing of the processing unit 12 proceeds to step S214.

[0098] In step S214, the processing unit 12 judges whether the active power P71 that optimizes the evaluation value is smaller than either of the active powers P63 or P64. The active powers P63 and P64 are values ​​calculated in steps S203a and S204a in FIG. 12A. In step S214, if the active power P71 is smaller than either of the active powers P63 and P64 (S214: Yes), the processing of the processing unit 12 proceeds to step S215. That is, if the active power P71 is smaller than the larger of the active powers P63 and P63, the processing of the processing unit 12 proceeds to step S215. In this case, although not shown, the optimal point M (P71, Q71) exists on the negative side (lower side of the paper) in the P-axis direction than the provisional controllable range X2 (see FIG. 13).

[0099] In step S215, the processing unit 12 performs an overwrite process of the active powers P63, P64 and the reactive powers Q63, Q64. That is, the processing unit 12 changes the active powers P63, P64 and the reactive powers Q63, Q64 so that the controllable range X3 includes the optimal point M. Specifically, the overwrite process is performed so that the values ​​of the active powers P63, P64 become equal to the value of the active power P71 at the optimal point M. Moreover, for the reactive power Q63, a process is performed in which the reactive power Q value when (-α×active power P71+β×reactive power Q) is maximized is overwritten at the interconnection point 41 (see FIG. 1B) of the external system model 31 (see FIG. 1B). For the other reactive power Q64, a process is performed in which the reactive power Q value when (-α×active power P71-β×reactive power Q) is maximized is overwritten at the interconnection point 41 (see FIG. 1B) of the external system model 31 (see FIG. 1B). After performing the process of step S215, in step S213, the processing unit 12 sets a controllable range.

[0100] In addition, if the active power P71 of the optimal point M is not smaller than either the active power P63 or the active power P64 in step S214 (S214: No), the processing of the processing unit 12 proceeds to step S216. In other words, if the active power P71 of the optimal point M is equal to or greater than the active power P63 and equal to or greater than the active power P64, the processing of the processing unit 12 proceeds to step S216.

[0101] In step S216, the processing unit 12 judges whether or not the reactive power Q71 that optimizes the evaluation value is greater than either of the reactive powers Q61 and Q63. The reactive powers Q61 and Q63 are values ​​calculated in steps S201a and S203a in FIG. 12A. If the reactive power Q71 is greater than either of the reactive powers Q61 and Q63 in step S216 (S216: Yes), the processing of the processing unit 12 proceeds to step S217. In this case, although not shown, the optimal point M (P71, Q71) is present on the positive side in the Q-axis direction (right side of the drawing) of the controllable range X2 (see FIG. 13).

[0102] In step S217, the processing unit 12 performs an overwrite process of the active powers P61, P63 and the reactive powers Q61, Q63. That is, the processing unit 12 changes the active powers P61, P63 and the reactive powers Q61, Q63 so that the controllable range X3 includes the optimal point M. Specifically, the overwrite process is performed so that the values ​​of the reactive powers Q61, Q63 become equal to the value of the reactive power Q71 at the optimal point M. Moreover, for the active power P61, a process is performed in which the active power P value when (α×active power P+β×reactive power Q71) is maximized is overwritten at the interconnection point 41 (see FIG. 1B) of the external system model 31 (see FIG. 1B). For the other active power P63, a process is performed in which the active power P value when (-α×active power P+β×reactive power Q71) is maximized is overwritten at the interconnection point 41 (see FIG. 1B) of the external system model 31 (see FIG. 1B). After performing the process of step S217, in step S213, the processing unit 12 sets a controllable range.

[0103] Moreover, in step S216, if the reactive power Q71 of the optimal point M is not greater than either the reactive power Q61 or the reactive power Q63 (S216: No), the processing of the processing unit 12 proceeds to step S218. In step S218, the processing unit 12 judges whether or not the reactive power Q71 that optimizes the evaluation value is smaller than either the reactive power Q62 or the reactive power Q64. The reactive powers Q62 and Q64 are values ​​calculated in steps S202a and S204a in FIG. 12A. If the reactive power Q71 is smaller than either the reactive power Q62 or the reactive power Q64 in step S218 (S218: Yes), the processing of the processing unit 12 proceeds to step S219. In this case, although not shown, the optimal point M (P71, Q71) is present on the negative side (left side of the drawing) in the Q-axis direction from the controllable range X2 (see FIG. 13).

[0104] In step S219, the processing unit 12 performs an overwrite process of the active powers P62, P64 and the reactive powers Q62, Q64. That is, the processing unit 12 changes the active powers P62, P64 and the reactive powers Q62, Q64 so that the controllable range X3 includes the optimal point M. Specifically, the overwrite process is performed so that the values ​​of the reactive powers Q62, Q64 become equal to the value of the reactive power Q71 at the optimal point M. Moreover, for the active power P62, a process is performed in which the active power P value when (α×active power P-β×reactive power Q71) is maximized is overwritten at the interconnection point 41 (see FIG. 1B) of the external system model 31 (see FIG. 1B). For the other active power P64, a process is performed in which the active power P value when (-α×active power P-β×reactive power Q71) is maximized is overwritten at the interconnection point 41 (see FIG. 1B) of the external system model 31 (see FIG. 1B). After performing the process of step S219, in step S213, the processing unit 12 sets a controllable range.

[0105] Moreover, if the reactive power Q71 is not smaller than either the reactive power Q62 or the reactive power Q64 in step S218 (S218: No), the processing unit 12 sets the controllable range in step S213 without particularly performing an overwrite process of the active power P or the reactive power Q. In this case, the optimal point M is included in the controllable range X2 (see FIG. 13) specified by the active powers P61 to P64 and the reactive powers Q61 to Q64, even without performing an overwrite process. The order of the determination processes of steps S211, S214, S216, and S218 may be changed as appropriate. Similar processes are also performed for setting the controllable range at the other interconnection point 42 (see FIG. 1B).

[0106] <Effects> According to the third embodiment, the controllable range X3 is set so as to include the variable values ​​of the electrical physical quantities (active power P71 and reactive power Q71) when the evaluation value is optimized in the external system models 31, 32 (see FIG. 1B). Therefore, the objective function can be created based on information including a relatively high evaluation value. This allows the control amount of the control device of the main system 20W (see FIG. 1A) to be appropriately set.

[0107] Fourth Embodiment The fourth embodiment differs from the first embodiment in that the objective function is a piecewise linear function. Note that the configuration of the reduced model creation system 10 (see FIG. 2) and the processes other than the creation of the objective function (see FIGS. 3 to 7) are the same as those of the first embodiment. Therefore, only the parts that differ from the first embodiment will be described, and a description of the overlapping parts will be omitted.

[0108] FIG. 14 is a flowchart of a process relating to the creation of an objective function in the reduced model creation system according to the fourth embodiment (also see FIG. 2 as appropriate). The series of processes shown in Fig. 14 corresponds to step S4 in Fig. 3. At the time of "START" in Fig. 14, it is assumed that evaluation values ​​have been calculated for each of the reference point E in Fig. 7 as well as points F, G, H, and K. In step S401a, the processing unit 12 creates a piecewise objective function with the active power P as a variable. That is, the processing unit 12 creates an objective function with the active power P as a variable based on each evaluation value specified by a predetermined reactive power Q at the interconnection point 41 (see FIG. 1B) of the external system model 31 (see FIG. 1B) and a plurality of active powers P with different magnitudes. In the example of FIG. 7, evaluation values ​​are calculated at each of the reference point E and points F and G where the values ​​of the active power P are different. Based on these evaluation values ​​and the active power P, an objective function with the active power P as a variable is created as a piecewise linear function.

[0109] FIG. 15A is an explanatory diagram of an objective function with active power P as a variable. Note that points Ec1, Gc1, and Fc1 shown in Fig. 15A are similar to those in Fig. 9A described in the first embodiment. In the first embodiment, an objective function represented by a graph of a straight line L3 (see Fig. 9A) is created, but in the fourth embodiment, a piecewise linear function represented by a broken line graph is created as the objective function as shown in Fig. 15A.

[0110] Specifically, in the range of the active power P33 of the lower limit or more and the active power P40 of the reference point E (see FIG. 7) or less, an objective function of the graph of the line segment L5 connecting the points Gc1 and Ec1 is created. The objective function of the graph of the line segment L5 is expressed, for example, by the linear function of the following formula (9). Note that the "active power P 下限 " is the lower limit value of the active power P, and corresponds to the active power P33 in FIG. 15A. Furthermore, a7 and b7 included in the equation (9) are predetermined values.

[0111] a7 × (active power P) + b7 [active power P 下限 ≦Active power P ≦ Active power P40] ...(Formula 9)

[0112] In addition, in the range that is greater than the active power P40 at the reference point E (see FIG. 7) and is equal to or less than the upper limit active power P32, an objective function is created for the graph of the line segment L6 that connects the points Ec1 and Fc1. The objective function for the graph of the line segment L6 is expressed as a linear function of the following equation (10). Note that the "active power P 上限 " is the upper limit value of the active power P, and corresponds to the active power P32 in FIG. 15A. Furthermore, c7 and d7 included in the formula (10) are predetermined values.

[0113] c7×(active power P)+d7 [active power P40<active power P≦active power P 上限 ] ...(Equation 10)

[0114] Next, in step S402a of Fig. 14, the processing unit 12 creates a piecewise objective function with reactive power Q as a variable. That is, the processing unit 12 creates an objective function with reactive power Q as a variable based on each evaluation value specified by a predetermined active power P at the interconnection point 41 (see Fig. 1B) of the external system model 31 (see Fig. 1B) and reactive power Q of different magnitudes. In the example of Fig. 7, evaluation values ​​are calculated at each of the reference point E and points H and K where the values ​​of reactive power Q are different. Based on these evaluation values ​​and reactive power Q, an objective function with reactive power Q as a variable is created as a piecewise linear function.

[0115] FIG. 15B is an explanatory diagram of an objective function with reactive power Q as a variable. Note that points Ec2, Kc2, and Hc2 shown in Fig. 15B are similar to those in Fig. 9B described in the first embodiment. In the first embodiment, an objective function represented by a graph of a straight line L4 (see Fig. 9B) is created, but in the fourth embodiment, a piecewise linear function represented by a broken line graph is created as the objective function as shown in Fig. 15B.

[0116] Specifically, in the range of the reactive power Q34 of the lower limit or more and the reactive power Q40 of the reference point E (see FIG. 7) or less, an objective function of the graph of the line segment L7 connecting the point Kc2 and the point Ec2 is created. The objective function of the graph of the line segment L7 is expressed, for example, by the linear function of the following formula (11). Note that the "reactive power Q 下限 " is the lower limit value of reactive power Q, and corresponds to reactive power Q34 in FIG. 15B. Furthermore, a8 and b8 included in equation (11) are predetermined values.

[0117] a8 × (reactive power Q) + b8 [reactive power Q 下限 ≦ reactive power Q ≦ reactive power Q40] ...(Formula 11)

[0118] In addition, in the range that is greater than the reactive power Q40 of the reference point E (see FIG. 7) and is equal to or less than the upper limit reactive power Q31, an objective function of the graph of the line segment L8 connecting the point Ec2 and the point Hc2 is created. The objective function of the graph of the line segment L8 is expressed as a linear function of the following equation (12). Note that the "reactive power Q 上限 " is the upper limit value of reactive power Q, and corresponds to reactive power Q31 in FIG. 15B. Furthermore, c8 and d8 included in formula (11) are predetermined values.

[0119] c8 × (reactive power Q) + d8 [reactive power Q40 < reactive power Q ≦ reactive power Q 上限 ] ...(Equation 12)

[0120] In this manner, the processing unit 12 creates an objective function having the active power P and the reactive power Q as variables as a piecewise linear function.

[0121] <Effects> According to the fourth embodiment, the objective functions of the external system reduction models 31a and 32a (see FIG. 1C) are created as piecewise linear functions. This makes it possible to reduce the error of the objective function (error with respect to an optimal predetermined objective function) and to improve accuracy, compared to the case where the objective function is expressed as a straight line graph (see FIG. 9A and FIG. 9B).

[0122] Fifth embodiment In the fifth embodiment, a control amount determination system 100 (see FIG. 16) that determines the control amount of a control device of a main system 20W (see FIG. 1A) using the external system contraction models 31a, 31b (see FIG. 1C) described in the first embodiment will be described. Note that the configuration and processing related to the calculation of the external system contraction models 31a, 31b are similar to those in the first embodiment. Therefore, only the parts different from the first embodiment will be described, and the description of the overlapping parts will be omitted.

[0123] FIG. 16 is a functional block diagram including a control amount determination system 100 according to the fifth embodiment. The control amount determination system 100 shown in Fig. 16 is a system that determines the control amount of a control device of the main system 20W (see Fig. 1A). As described above, the main system 20W is modeled as the main system model 20 (see Fig. 1C). As shown in Fig. 16, the control amount determination system 100 includes a reduced model creation system 10, a main system information input unit 61, a main system control amount determination unit 62, and a main system control amount output unit 63.

[0124] The reduced model creation system 10 is a system that reduces external system models 31 and 32 (see FIG. 1B) to create external system reduced models 31a and 32a (see FIG. 1C). The configuration and processing of the reduced model creation system 10 are similar to those of the first embodiment (see FIG. 2), and therefore will not be described.

[0125] The main system information input unit 61 is an interface for inputting information on the main system model 20 (see FIG. 1C). That is, information on the main system model 20 (see FIG. 1C), which is a model of the main system 20W (power system: see FIG. 1A), is input to the main system information input unit 61. In the example of FIG. 16, the information input unit 121 is connected to the input device 51, but is not limited to this. For example, the information input unit 121 may acquire information from a predetermined database (not shown) or a measuring instrument (not shown).

[0126] The main system control quantity determination unit 62 determines the control quantities of the control devices of the main system 20W (power system: see Figure 1A) based on the external system abbreviated models 31a, 32a (see Figure 1C) created by the abbreviated model creation system 10 and the main system model 20 (see Figure 1C) input via the main system information input unit 61.

[0127] For example, the main system control amount determination unit 62 determines the control amount of the control device of the main system 20W (see FIG. 1A) by performing optimization using the objective functions of the main system model 20 and the external system abridged models 31a, 32a within a range defined by the constraint conditions of the main system model 20 (see FIG. 1C) and the constraint conditions of the external system abridged models 31a, 32a (see FIG. 1C). The main system control amount output unit 63 causes the display device 52 to display the control amount determined by the main system control amount determination unit 62 in a predetermined manner.

[0128] <Effects> According to the fifth embodiment, the control amount of the control device of the main system 20W (see FIG. 1A) can be determined based on the constraint conditions and objective functions of the external system contraction models 31a and 32a (see FIG. 1C) as well as the constraint conditions and objective functions of the main system model 20 (see FIG. 1C). This makes it possible to stably supply power to consumers while keeping the frequency and voltage in the main system 20W within the allowable ranges.

[0129] Sixth Embodiment In the sixth embodiment, a control amount determination system 100A (see FIG. 17) that determines the control amount of the control device of the main system 20W (see FIG. 1A) and determines the control amount of the control device of the external systems 31W and 32W (see FIG. 1A) using the external system contraction models 31a and 31b (see FIG. 1C) described in the first embodiment will be described. Note that the configuration and processing related to the calculation of the external system contraction models 31a and 31b are similar to those in the first embodiment. Therefore, the parts different from the first embodiment will be described, and the explanation of the overlapping parts will be omitted.

[0130] FIG. 17 is a functional block diagram including a control amount determination system 100A according to the sixth embodiment. The control amount determination system 100A shown in FIG. 17 is a system that determines the control amount of the control device of the main system 20W (see FIG. 1A) and determines the control amount of the control device of the external systems 31W, 32W (see FIG. 1A). As shown in FIG. 17, the control amount determination system 100A includes a contracted model creation system 10, a main system information input unit 61, a main system control amount determination unit 62, and a main system control amount output unit 63. In addition to the above-mentioned configuration, the control amount determination system 100A also includes an external system information input unit 71, an external system control amount determination unit 72, and an external system control amount output unit 73. Note that the contracted model creation system 10, the main system information input unit 61, and the main system control amount output unit 63 are the same as those described in the fifth embodiment (see FIG. 16), so that the description thereof will be omitted.

[0131] The main system control amount determination unit 62 determines the control amount of the control devices of the main system 20W (electric power system: see FIG. 1A), and calculates the active power (electrical physical quantity) and reactive power (electrical physical quantity) of the main system 20W at the interconnection points 41W, 42W (see FIG. 1A). The external system information input unit 71 is an interface for inputting information of the external system models 31, 32 (see FIG. 1B).

[0132] The external system control amount determination unit 72 determines the control amount of the control devices of the external systems 31W, 32W (see FIG. 1A). That is, the external system control amount determination unit 72 determines the control amount of the control devices of the external systems 31W, 32W based on the active power (electrical physical quantity) and reactive power (electrical physical quantity) of the main system 20W (power system: see FIG. 1A) at the interconnection points 41W, 42W (see FIG. 1A) and the external system models 31, 32 (see FIG. 1B).

[0133] For example, the external system control amount determination unit 72 determines the control amount of the control device of the external system 31W (see FIG. 1A) by optimizing each objective function of the main system model 20 (see FIG. 1B) and the external system model 31 (see FIG. 1B) within the range of active power and reactive power defined by the constraint condition of the main system model 20 (see FIG. 1B) at the interconnection point 41 (see FIG. 1B) and the constraint condition of the external system reduced model 31a (see FIG. 1C). In the same manner, the external system control amount determination unit 72 also determines the control amount of the control device of the other external system 32W (see FIG. 1A). The external system control amount output unit 73 causes the display device 52 to display the control amount determined by the external system control amount determination unit 72.

[0134] <Effects> According to the sixth embodiment, by optimizing the objective functions of the main system model 20 and the external system models 31, 32, the control amount of the control device of the main system 20W can be determined, and the control amount of the control devices of the external systems 31W, 32W can also be determined.

[0135] <<Variations>> The reduced model creation system 10 and the reduced model creation method according to the present disclosure, as well as the controlled variable determination systems 100 and 100A, have been described in the above embodiments. However, the present disclosure is not limited to these descriptions, and various modifications can be made. For example, in each embodiment, the case where two external systems 31W, 32W (see FIG. 1A) are connected to the main system 20W (see FIG. 1A) has been described, but the present invention is not limited to this. That is, the number of external systems connected to the main system 20W may be one, or may be three or more. In this case, the external systems and the interconnection points are in one-to-one correspondence.

[0136] In the first embodiment, a total of five evaluation values ​​are calculated under different conditions in steps S301 to S305 in Fig. 6, but this is not limited to the above. That is, the number of conditions for calculating the evaluation values ​​may be two or more. The same can be said for the other embodiments.

[0137] Furthermore, in addition to the information including the controllable range X1 (see FIG. 5) described in the first embodiment, information including a plurality of conditions (see FIG. 7) when an evaluation value is calculated in the controllable range X1 may be displayed on the display device 52 (see FIG. 2). Also, graphs and formulas of the objective functions shown in FIG. 9A and FIG. 9B may be displayed on the display device 52. In addition, the provisional controllable range X2 and the final controllable range X3 shown in FIG. 13 may be displayed on the display device 52 in an overlapping state. This makes it easier for the user to grasp the information on the controllable range and the evaluation value.

[0138] The optimization method is not limited to those described in the embodiments. For example, in addition to optimizing the evaluation values ​​at the interconnection points 41 and 42, multi-objective optimization such as maximizing the active power P, maximizing the reactive power Q, minimizing the active power P, and minimizing the reactive power Q may be performed. In the fourth embodiment, a case has been described in which a piecewise linear function is used as the objective function, but the present invention is not limited to this. For example, a predetermined function that forms a curved graph may be used as the objective function.

[0139] In addition, in each embodiment, the case where the active power P and the reactive power Q are used as the electrical physical quantity has been described, but the present invention is not limited to this. That is, at least one of the active power P, the reactive power Q, the voltage V, the current I, and the phase angle θ may be used as the electrical physical quantity.

[0140] Moreover, each embodiment can be appropriately combined. For example, the second embodiment and the fourth embodiment can be combined so that the processing unit 12 multiplies the active power P and the reactive power Q by a predetermined weighting coefficient when setting the controllable range (second embodiment), and furthermore, a piecewise linear function can be used as the objective function (fourth embodiment). In addition, for example, a combination of the third embodiment and the fifth embodiment, or a combination of the third embodiment and the sixth embodiment is also possible. Also, various combinations are possible, such as a combination of the fourth embodiment and the fifth embodiment, a combination of the fourth embodiment and the sixth embodiment, and a combination of three or more embodiments.

[0141] The processing of the reduced model creation system 10 (reduced model creation method) may be executed as a predetermined program of a computer. The program can be provided via a communication line, or written on a predetermined recording medium and distributed.

[0142] In addition, the present disclosure is not limited to each embodiment, and various modified examples are included. For example, each embodiment has been described in detail to clearly explain the present disclosure, and is not necessarily limited to those having all of the configurations described. In addition, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another example to the configuration of one embodiment. In addition, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

[0143] In addition, the above-mentioned configurations, functions, processing units, processing means, etc. may be realized in part or in whole by hardware, for example, by designing them as integrated circuits. In addition, the above-mentioned configurations, functions, etc. may be realized in software by a processor interpreting and executing a program that realizes each function. Information such as the program, table, file, etc. that realizes each function can be stored in a memory, a recording device such as a hard disk or SSD (Solid State Drive), or a recording medium such as an IC card, SD card, or DVD. In addition, the control lines and information lines shown are those that are considered necessary for the explanation, and not all control lines and information lines in the product are necessarily shown. In reality, it can be considered that almost all components are connected to each other. [Explanation of symbols]

[0144] 10. Reduced model creation system 11 Storage section 12 Processing section 121 Information input section 122 Controllable range creation unit 123 Evaluation value calculation unit 124 Objective function creation section 125 Reduced model output section 20 Main Power System Model 31,32 External system model 31a, 32a External system reduction model 41,42 Connection point 51 Input Devices 52 Display device 61 Main system information input section 62 Main system control amount determination unit 63 Main system control amount output section 71 External system information input section 72 External system control amount determination unit 73 External system control amount output section 100,100A Control Quantity Determination System 41W,42W interconnection point X1, X2, X3 Controllable range 20W main system (prescribed power system) 31W,32W external system

Claims

1. a processing unit that reduces an external system model that is a model of each of a plurality of external systems to create an external system reduced model; Each of the plurality of external systems is connected to a predetermined power system via an interconnection point; The processing unit displays information including a constraint condition indicating a controllable range of a predetermined electrical physical quantity of the external system at the interconnection point and an objective function having the electrical physical quantity as a variable as the external system contraction model on a display device in association with the interconnection point.

2. The electrical physical quantities include active power and reactive power.

2. The system for creating a reduced model according to claim 1 .

3. When creating the controllable range based on a predetermined formula including the active power and the reactive power of the external grid model at the interconnection point, the processing unit multiplies each of the active power and the reactive power included in the formula by a predetermined weighting coefficient.

3. The system for creating a reduced model according to claim 2.

4. the processing unit calculates a predetermined evaluation value for each of a plurality of conditions in which the value of the electrical physical quantity is different within the controllable range, and creates the objective function based on the electrical physical quantity and the evaluation value corresponding to the plurality of conditions.

2. The system for creating a reduced model according to claim 1 .

5. The plurality of conditions include a condition that maximizes or minimizes the evaluation value in the controllable range.

5. The system for creating a reduced model according to claim 4.

6. The processing unit creates the objective function as a piecewise linear function.

5. The system for creating a reduced model according to claim 4.

7. The processing unit creates the controllable range so that a point indicating a condition when a predetermined evaluation value becomes maximum or minimum is included in the controllable range.

2. The system for creating a reduced model according to claim 1 .

8. The system for creating a reduced model according to any one of claims 1 to 7, a main system information input unit to which information of a main system model which is a model of the power system is input; a main system control amount determination unit that determines a control amount of a control device of the power system based on the external system reduction model and the main system model; a main system control amount output unit that causes the display device to display the control amount determined by the main system control amount determination unit.

9. an external system information input unit to which information of the external system model is input; An external system control amount determination unit that determines a control amount of a control device of the external system; an external system control amount output unit that displays the control amount determined by the external system control amount determination unit on the display device; the main system control variable determination unit determines a control variable of the control device of the power system and calculates the electrical physical quantity of the power system at the interconnection point; The external system control amount determination unit determines a control amount of the control device of the external system based on the electrical physical amount of the power system at the interconnection point and the external system model.

9. The control amount determination system according to claim 8,

10. a reduced model creation process for creating an external system reduced model by reducing an external system model that is a model of each of a plurality of external systems; and displaying the external system contraction model on a display device in association with each of interconnection points between the plurality of external systems and a predetermined power system, a reduced model creation method, in which the reduced model creation process creates, as the external system reduced model, information including a constraint condition indicating a controllable range of a predetermined electrical physical quantity of the external system at the interconnection point and an objective function having the electrical physical quantity as a variable.

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