JP2016111780A - Manipulated variable calculation device, control method for manipulated variable calculation device, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To calculate a manipulated variable for a manipulation target facility of a power system by performing optimal tidal current calculation while taking voltage stability of the entire power system into account.SOLUTION: A manipulated variable calculation device is configured to calculate the manipulated variable for the manipulation target facility that the power system includes. The manipulated variable calculation device is characterized in comprising: an acquisition part which acquires a first calculation formula for calculating cost with manipulation to the manipulation target facility, a second calculation formula for calculating a load margin that is a power increase amount to stability limit power that is a power demand at the time when a voltage in the power system becomes unstable, and a restriction condition during operation of the manipulation target facility; and a manipulated variable calculation part for calculating the manipulated variable for the manipulation target facility while satisfying the restriction condition and in such a manner that a predetermined index value calculated from the first calculation formula and the second calculation formula becomes a predetermined value.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an operation amount calculation device, a control method for an operation amount calculation device, and a program.

  It is widely used to calculate the optimal power flow when formulating power system operation plans. The optimal power flow calculation is based on the fuel cost and cost when generating power according to the power demand within the limits of operation of power system components such as power generation equipment, transformers, phase adjustment equipment, and transmission and distribution lines. This is a technique for calculating an operation amount for an operation target facility such as a power generation facility so as to maximize or minimize a predetermined evaluation index such as a power transmission loss.

  When formulas for calculating evaluation indices such as fuel cost cost and power transmission loss are given as objective functions, operation constraints of the power system are given as constraint conditions, and the operation amount for the operation target equipment is given as a state variable of the objective function, Optimal power flow calculation is an optimization problem with constraints (see, for example, Patent Document 1).

  In addition, when performing this optimal power flow calculation, by adding conditions related to transient stability to the constraints, the amount of operation for each component of the power system can be reduced while taking into account operational continuity when a failure occurs in the power system. A calculation technique has been developed (see, for example, Patent Document 2).

  Transient stability is an index that indicates the degree to which the synchronous operation of the power generation facility can be stably continued in the event of a disturbance due to an equipment failure in the power system. It is.

  On the other hand, the voltage of the power system fluctuates when there is some disturbance in the power system. In this case, the ability of the power system voltage to settle to a new equilibrium point or a property related thereto is referred to as voltage stability of the power system.

  Several methods for analyzing the voltage stability of the power system have been developed (see, for example, Non-Patent Document 1), but it is also possible to analyze by examining the PV characteristics of the power system. The PV characteristic is a characteristic indicating the relationship between the active power P and the voltage V of the load in the power system, and is on a two-dimensional coordinate plane in which the horizontal axis corresponds to the active power P and the vertical axis corresponds to the voltage V. It is expressed by a so-called PV curve or PV curve constituted by the locus of a plurality of plotted points.

  Then, by using this PV curve, it is possible to calculate a load margin that is a difference from the current power demand at the operating point to the upper limit value (stability limit power) of the power demand (see, for example, Patent Document 3). .

JP 2006-174564 A JP 2001-339861 A JP 2011-1115024 A

Naoto Ashino and three other authors, "Approximation method of nearest saddle node bifurcation point based on power flow multiple roots-Proposal of new monitoring and control method of voltage stability", Electrical Engineering B, No. 119, Vol. 4, pp.507-515, 1999

  However, since the PV characteristics are calculated for each load, it is difficult to take into account the voltage stability of the power system when performing an optimal power flow calculation and generating an operation plan of the power system. .

  The present invention has been made in view of such a problem, and an operation amount capable of obtaining an operation amount for an operation target facility of the power system by performing an optimum power flow calculation in consideration of voltage stability of the entire power system. It is an object to provide a calculation device, a control method for an operation amount calculation device, and a program.

  One of means for solving the above-mentioned problem is an operation amount calculation device that calculates an operation amount for an operation target facility included in an electric power system, and is a first unit for calculating a cost associated with an operation on the operation target facility. A calculation formula, a second calculation formula for calculating a load margin that is a power increase amount up to a stable limit power that is a power demand when the voltage in the power system becomes unstable, and An acquisition unit that acquires a constraint condition, and the operation target facility is satisfied so that a predetermined index value calculated from the first calculation formula and the second calculation formula becomes a predetermined value while satisfying the constraint condition. An operation amount calculation unit that calculates an operation amount.

  In addition, the problems disclosed by the present application and the solutions thereof will be clarified by the description in the column of the embodiment for carrying out the invention and the description of the drawings.

  ADVANTAGE OF THE INVENTION According to this invention, the optimal power flow calculation can be performed in consideration of the voltage stability of the whole electric power system, and the operation amount with respect to the operation target equipment of an electric power system can be calculated | required.

It is a figure which shows the function structure of the operation amount calculation apparatus. It is a figure which shows the hardware constitutions of the operation amount calculation apparatus. It is a figure which shows the memory | storage device of the operation amount calculation apparatus. It is a figure which shows an electric power grid | system. It is a flowchart which shows the flow of a process of the operation amount calculation method.

  At least the following matters will become apparent from the description of this specification and the accompanying drawings.

== Power system ==
As shown in FIG. 4, the power system 1000 includes a plurality of power generation facilities 1100 and a plurality of load facilities 1200.

  The power generation facility 1100 is a power source that can extract and supply power energy from an energy source, and includes, for example, a hydroelectric generator, a nuclear power generator, a thermal power generator, and the like.

  The load device 1200 is an electrical device in a factory, home, or the like that consumes the power supplied from the power generation facility 1100.

  Although not shown in FIG. 4, the power system 1000 includes a power transmission line T such as a power transmission line and a distribution line, a phase adjusting equipment S that controls the phase of power, a power storage equipment B, a transformer H, a switch K, and the like. It is configured with various facilities.

== Operation amount calculation device ==
The operation amount calculation device 100 according to the present embodiment is an information processing device that calculates an operation amount for a power generation facility 1100 (operation target facility) included in the power system 1000.

  In this embodiment, for simplification of description, the case where the power generation facility 1100 is an operation target facility will be described as an example. However, the operation target facility is not limited to the power generation facility 1100, and the above-described phase adjustment facility S and power storage Equipment B, transformer H, switch K, etc. may be included.

  An overall configuration of the operation amount calculation apparatus 100 according to the present embodiment is shown in FIGS. 1 and 2. FIG. 1 is a diagram for explaining a functional configuration of the operation amount calculating apparatus 100, and FIG. 2 is a diagram for explaining a hardware configuration of the operation amount calculating apparatus 100.

  As illustrated in FIG. 2, the operation amount calculation device 100 according to the present embodiment includes a CPU (Central Processing Unit) 110, a memory 120, a communication device 130, a storage device 140, an input device 150, an output device 160, and a recording medium reading device. The computer is configured to include 170.

  The CPU 110 is responsible for overall control of the operation amount calculation apparatus 100, and reads out and executes a control program 600 composed of codes for performing various operations according to the present embodiment stored in the storage device 140 to the memory 120. By doing so, various functions as the operation amount calculation apparatus 100 are realized.

  For example, although the details will be described later, the control program 600 is executed by the CPU 110 and cooperates with hardware devices such as the memory 120, the communication device 130, and the storage device 140, thereby obtaining the acquisition unit 101, the operation amount calculation unit 102, and the like. Is realized.

  The memory 120 can be configured by a semiconductor memory device, for example.

  The communication device 130 is a network interface such as a network card. The communication device 130 receives data from another computer via a network such as the Internet or a LAN (Local Area Network), and stores the received data in the storage device 140 or the memory 120. Further, the communication device 130 transmits data stored in the storage device 140 or the memory 120 to another computer via the network.

  The input device 150 is a device such as a keyboard, a mouse, and a microphone, and is a device for accepting input of information by an operator of the operation amount calculation device 100. The output device 160 is a device such as an LCD (Liquid Crystal Display), a printer, or a speaker, and is a device for outputting information.

  The storage device 140 can be constituted by, for example, a hard disk device or a semiconductor storage device. The storage device 140 is a device that provides a storage area for storing various programs, data, tables, and the like. FIG. 3 shows a state where the control program 600 and the data storage unit 700 are stored in the storage device 140.

  The control program 600 is stored in the manipulated variable calculation device 100 by reading it from the recording medium (various optical disks, magnetic disks, semiconductor memory, etc.) 800 to the storage device 140 using the recording medium reader 170. It can also be stored in the manipulated variable calculation device 100 by obtaining from another computer that is communicably connected via the communication device 130.

  The data storage unit 700 also stores objective functions, constraint conditions, system information, and the like that are referred to by the operation amount calculation unit 102 described later. Details of these will be described later.

  Next, as illustrated in FIG. 1, the operation amount calculation apparatus 100 according to the present embodiment includes the functional blocks of an acquisition unit 101 and an operation amount calculation unit 102.

  The acquisition unit 101 acquires system information representing the configuration of the power system 1000 and the electrical characteristics of each component from the input device 150 or the communication device 130 and stores the system information in the data storage unit 700.

  The system information includes, for example, the length and line impedance of the transmission line T, the position and active power and reactive power of the load facility 1200, the position and fuel cost coefficient (index such as yen / kWh) of the power generation facility 1100, active power and reactive power. , The position of the power storage facility B in the power system 1000, active power and reactive power, the position and capacity of the phase adjusting facility S, the upper and lower limit values for the node voltage, and the like.

  The acquisition unit 101 also inputs the objective function used when the manipulated variable calculation device 100 performs the optimum power flow calculation and the constraint conditions during operation of each operation target facility of the power system 1000 such as the power generation facility 1100, the input device 150 or the communication. Obtained from the device 130 and stored in the data storage unit 700.

  Although the details will be described later, the objective function according to the present embodiment includes a first calculation formula for calculating the power generation cost of the power generation facility 1100 (cost associated with the operation on the operation target facility) and the voltage in the power system 1000. A second calculation formula for calculating the load margin that is the amount of power increase up to the stability limit power that is the power demand when becoming stable is included.

  This objective function is to calculate a predetermined index value related to the power system 1000. In this embodiment, as an example, the sum of a power generation cost and a value obtained by multiplying the reciprocal of the load margin by a predetermined coefficient is calculated. I am going to do it. The first calculation formula for calculating the index value is an example. In addition to the power generation cost, for example, transmission loss, reactive power loss (delay), carbon dioxide (CO2) emissions, or a combination thereof The calculated value may be calculated.

  Next, the operation amount calculation unit 102 uses the system information, the constraint condition, and the objective function to generate the power generation facility 1100 so that the value of the objective function is a predetermined value (for example, the minimum value or the maximum value) while satisfying the constraint condition. The operation amount for is calculated.

  That is, the operation amount calculation unit 102 uses the objective function, the constraint condition, and the system information to calculate the operation amount for the power generation facility 1100 so that the operation state of the power system 1000 becomes a more preferable state. The operation amount calculation unit 102 calculates an optimal solution by performing an optimal power flow calculation using an optimization method such as mathematical programming.

  Next, the optimum power flow calculation performed by the operation amount calculation device 100 according to the present embodiment will be described.

  The manipulated variable calculation device 100 according to the present embodiment is formulated such that the first calculation formula for calculating the power generation cost and the second calculation formula for calculating the load margin are included in the objective function. Calculate the optimal power flow.

  By such an aspect, it becomes possible to calculate the amount of operation with respect to the power generation facility 1100 of the power system 1000 by performing the optimal power flow calculation in consideration of the voltage stability of the entire power system 1000.

  Note that the power system 1000 has a load increase scenario that is a method of increasing power demand until the voltage of the power system 1000 becomes unstable in performing the optimum power flow calculation considering the voltage stability of the power system 1000. Although it can be expressed as a vector having the power demand increase amount of each load facility 1200 as an element, there are many such load increase scenarios. Therefore, when performing the above-mentioned optimal power flow calculation, it is necessary to specify a load increase scenario first.

  In the present embodiment, the load increase scenario with a smaller load margin leads to the voltage collapse of the power system 1000 earlier, so as an example, the optimum power flow calculation is performed assuming a load increase scenario with the smallest load margin. Do. That is, the current power demand of the plurality of load facilities 1200 included in the power system 1000 and the power when the voltage of the power system 1000 becomes unstable most quickly when the power demand of the plurality of load facilities 1200 increases. The optimal power flow calculation is performed assuming a load increase scenario in which the difference between demand and load is a margin. By calculating the optimum power flow assuming such a load increase scenario that should be warned, the operation amount for the power generation facility 1100 is calculated so as to improve the safety with respect to the voltage stability of the power system 1000. Is possible.

  Note that the load margin at this time is that the current power demand of the plurality of load facilities 1200 included in the power system 1000 and the voltage of the power system 1000 is the earliest when the power demand of the plurality of load facilities 1200 increases. It is calculated by the difference between the power demand when it becomes unstable.

  The minimum value of the load margin in the above load increase scenario can be obtained as a solution of equations (1) to (4).

minimize F (x, v) (1)
subject to g ₁ (v) = 0 (2)
J (v) ^T w = 0 (3)
| w | ≠ 0 (4)
Where x is the voltage vector at the operating point of the power system 1000, v is the voltage vector at the stability limit voltage (voltage collapse point), and F (x, v) is the stability limit voltage in the load increase scenario specified from the voltage x. The load margin up to v, g ₁ (v) is the power flow equation at the stability limit voltage v, J (v) is the Jacobian matrix of g ₁ (v) with respect to the stability limit voltage v, and w is the left of the Jacobian matrix It is an eigenvector.

  Expression (1) is an objective function (load margin), Expression (2) is a power flow equation, Expressions (3) and (4) are conditional expressions at the voltage collapse point, and Expressions (1) to (4) ) Satisfying the load margin F (x, v) is the minimum load margin.

  The load margin F (x, v) calculated in this way also varies depending on the operation amount u for the power system 1000.

  For this reason, the operation amount calculation apparatus 100 according to the present embodiment calculates the operation amount u such that the load margin F (x, v) is as large as possible when calculating the operation amount u for the power system 1000 by the optimal power flow calculation. . Thereby, it becomes possible to calculate the manipulated variable u for the power generation facility 1100 so as to improve the safety with respect to the voltage stability of the power system 1000.

  Specifically, the manipulated variable calculation device 100 performs optimal power flow calculation by solving an optimization problem given as a nonlinear optimization problem as in Expressions (5) to (11).

Minimize f (x, u, z) + a × 1 / F '' (x, u, v) (5)
Subject to g ₁ (x, u, z) = 0 (6)
g ₂ (x, u, z) = 0 (7)
h (x, u, z) ≤ 0 (8)
g ₁ (v, u, z) = 0 (9)
J (v) ^T w = 0 (10)
| w | ≠ 0 (11)
Here, x is a voltage vector at the operating point of the electric power system 1000, v is a voltage vector at the stability limit voltage (voltage collapse point), u is an operation amount, z is a variable that is dependent on the operation amount u (the power generation facility 1100). Reactive power, transformer tap value, etc.), a is a predetermined coefficient.

Equation (5) is the objective function, Equation (6) is the equation constraint expressed by the tidal equation at the operating point, Equation (7) is the equation constraint other than the tidal equation (characteristics of transformers, SVC (Static Var Compensator) )), Equation (8) is an inequality constraint (specified value of voltage, power flow value of transmission line T, etc.), equation (9) is an equation constraint expressed by a power flow equation at the voltage collapse point, J ( v) is the Jacobian matrix of g ₁ (v) with respect to the stability limit voltage v, and w is the left eigenvector of the Jacobian matrix.

  As shown in Expression (5), the objective function according to the present embodiment includes a first calculation expression f (x, u, z) for calculating an operation state such as fuel cost cost and power generation cost, and Expression (1). ) To formula (4) satisfying the formula (4), that is, a formula obtained by multiplying the reciprocal of the second formula F ″ (x, u, v) by a predetermined coefficient a for calculating the load margin (that is, the minimum value of the load margin); Including the sum of

  Note that F ″ (x, u, v) can be expressed by Expression (12).

F ″ (x, u, v) = min F ′ (x, u, v) (12)
Here, F ′ (x, u, v) is an extension of F (x, v) described in equation (1) so that the manipulated variable u is included in the variable.

  The manipulated variable calculation device 100 satisfies a constraint condition expressed by the equations (6) to (11) and calculates a predetermined index value (calculated by the first calculation equation) calculated by the objective function expressed by the equation (5). The operation amount u for the power generation facility 1100 is obtained so as to minimize the sum of the generated power cost and the value obtained by multiplying the reciprocal of the load margin calculated by the second calculation formula by a predetermined coefficient.

  As described above, the objective function according to the present embodiment is configured such that the predetermined index value is calculated using the reciprocal of the load margin calculated by the second calculation formula F ″ (x, u, v). Therefore, the operation amount calculation apparatus 100 according to the present embodiment can calculate the operation amount u that further improves the voltage stability of the power system 1000.

  Further, by obtaining the manipulated variable u that satisfies the equations (5) to (11), it is possible to obtain the manipulated variable u that optimizes the balance between the power generation cost and the voltage stability in the power system 1000. The optimum balance point can be adjusted by changing the coefficient a. That is, when the value of a is made larger, it is possible to obtain an operation amount u that places more importance on voltage stability than power generation cost (so that the load margin becomes larger), while the value of a is made more When the value is reduced, it is possible to obtain an operation amount u in which the power generation cost is more important than the voltage stability (so that the power generation cost is lower). According to such an aspect, it is possible to flexibly obtain an appropriate value of the operation amount u according to the operation state and operation policy of the power system 1000.

  Next, the process flow of the operation amount calculation apparatus 100 according to the present embodiment will be described with reference to the flowchart shown in FIG.

  First, the operation amount calculation device 100 acquires system information, objective functions, and constraint conditions representing the configuration of the power system 1000 and the electrical characteristics of each component from another computer through the input device 150 or the communication device 130, and The data is stored in the data storage unit 700 (S1000).

  Subsequently, the operation amount calculation apparatus 100 performs the optimum power flow calculation so that the predetermined index value calculated from the objective function becomes a predetermined value (for example, the minimum value) while satisfying the above-described constraints, and the power grid 1000 The optimum operation amount u for the power generation facility 1100 is obtained (S1010).

  Then, the operation amount calculation device 100 outputs the operation amount u, which is the result obtained as described above, to the output device 160 or another computer that is communicably connected (S1020).

  In the above embodiment, the second calculation formula F ″ (x, u, v) for calculating the load margin is included in the objective function of the formula (5), but as described below, It can also be included in the constraint conditions. In that case, the manipulated variable calculation device 100 satisfies the constraint conditions indicated by the equations (14) to (20), and the index value (first calculation equation f) calculated by the objective function indicated by the equation (13). The operation amount u for the power generation facility 1100 is obtained so as to minimize (the power generation cost calculated by (x, u, z)).

Minimize f (x, u, z) (13)
Subject to g ₁ (x, u, z) = 0 (14)
g ₂ (x, u, z) = 0 (15)
h (x, u, z) ≤ 0 (16)
g ₁ (v, u, z) = 0 (17)
J (v) ^T w = 0 (18)
| w | ≠ 0 (19)
F '' (x, u, v) ≧ F '' (x0, u0, v0) (20)
Here, Expressions (14) to (19) are the same as Expressions (6) to (11). Further, the equation (20) prevents the load margin in the power system 1000 from becoming smaller than the load margin at a certain reference time (for example, the load margin at the same time 24 hours ago) F ″ (x0, u0, v0). It is a restriction for.

  x0 is a voltage vector at the operating point of the electric power system 1000 at the reference time point, v0 is a voltage vector of a stability limit voltage (voltage collapse point) at the reference time point, and u0 is an operation amount at the reference time point.

  In addition, when calculating | requiring the operation amount u using Formula (13)-Formula (20), the operation amount u may not be decided uniquely, but in such a case, for example, Formula (13)-Formula ( 20) A candidate for the operation amount u satisfying 20) may be displayed on the output device 160 so that the operator of the operation amount calculation device 100 selects one of them. Or you may make it obtain | require the operation amount u when the value of the load margin which satisfy | fills Formula (20) becomes the maximum.

  As described above, according to the operation amount calculation apparatus 100 according to the present embodiment, the optimum power flow calculation is performed while considering the voltage stability of the entire power system 1000 to obtain the operation amount for the operation target facility of the power system 1000. It becomes possible.

  Further, the operation amount calculation apparatus 100 according to the present embodiment performs optimal power flow calculation assuming a load increase scenario in which the load margin is minimized. That is, the current power demand of the plurality of load facilities 1200 included in the power system 1000 and the power when the voltage of the power system 1000 becomes unstable most quickly when the power demand of the plurality of load facilities 1200 increases. The optimal power flow calculation is performed assuming a load increase scenario in which the difference between demand and load is a margin.

  By such an aspect, it is possible to perform an optimal power flow calculation assuming a load increase scenario that should be more cautious, and to reduce the operation amount for the operation target equipment so as to improve the safety with respect to the voltage stability of the power system 1000. It is possible to calculate.

  Further, the predetermined index value calculated from the objective function by the operation amount calculation apparatus 100 according to the present embodiment is the sum of the cost associated with the operation on the operation target facility and the value obtained by multiplying the reciprocal of the load margin by a predetermined coefficient. It is said. In this manner, it is possible to calculate the operation amount u for the operation target equipment while considering the voltage stability of the power system 1000, and to handle the multi-objective optimization problem as a single-purpose optimization problem. Is possible.

  Then, the operation amount calculation apparatus 100 according to the present embodiment calculates the operation amount u for the operation target facility so that the index value becomes the minimum value. By such an aspect, it is possible to calculate an optimal operation amount u that can suppress the cost while further improving the voltage stability of the power system 1000.

  The embodiments described above are for facilitating the understanding of the present invention, and are not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and equivalents thereof are also included in the present invention.

100 Operation amount calculation device 101 Acquisition unit 102 Operation amount calculation unit 110 CPU
120 Memory 130 Communication Device 140 Storage Device 150 Input Device 160 Output Device 170 Recording Medium Reading Device 600 Control Program 700 System Information 800 Recording Medium 1000 Power System 1100 Power Generation Facility 1200 Load Facility

Claims (6)

An operation amount calculation device that calculates an operation amount for an operation target facility of an electric power system,
A first calculation formula for calculating a cost associated with an operation on the operation target facility, and calculating a load margin that is an increase in power up to a stable limit power that is a power demand when the voltage in the power system becomes unstable. An acquisition unit for acquiring a second calculation formula for operation and a constraint condition during operation of the operation target facility;
An operation amount calculation unit that calculates an operation amount for the operation target facility so that the predetermined index value calculated from the first calculation formula and the second calculation formula becomes a predetermined value while satisfying the constraint condition. When,
An operation amount calculation apparatus comprising: The operation amount calculation device according to claim 1,
The load margin calculated by the second calculation formula is obtained when the current power demand of the plurality of load facilities included in the power system and the voltage of the power system when the power demand of the plurality of load facilities increases. A manipulated variable calculation device characterized by the difference between the power demand at the earliest and unstable time. The operation amount calculation device according to claim 1 or 2,
The operation amount calculation apparatus, wherein the predetermined index value is calculated by a sum of the cost and a value obtained by multiplying an inverse of the load margin by a predetermined coefficient. The operation amount calculation device according to claim 3,
The operation amount calculation unit is configured to calculate an operation amount for the operation target facility so that the predetermined index value becomes a minimum value while satisfying the constraint condition. A control method of an operation amount calculation device that calculates an operation amount for an operation target facility of an electric power system,
A first calculation formula for calculating the cost associated with the operation of the operation target equipment by the operation amount calculation device, an amount of power increase up to a stable limit power that is a power demand when the voltage in the power system becomes unstable A second calculation formula for calculating a load margin that is and a constraint condition during operation of the operation target equipment,
The operation amount for the operation target facility is such that the operation amount calculation device satisfies the constraint condition and the predetermined index value calculated from the first calculation formula and the second calculation formula becomes a predetermined value. A control method for an operation amount calculation apparatus, characterized in that In the operation amount calculation device that calculates the operation amount for the operation target equipment of the power system,
A first calculation formula for calculating a cost associated with an operation on the operation target facility, and calculating a load margin that is an increase in power up to a stable limit power that is a power demand when the voltage in the power system becomes unstable. A second calculation formula for acquiring the restriction condition during operation of the operation target equipment,
A procedure for calculating an operation amount for the operation target facility so that a predetermined index value calculated from the first calculation formula and the second calculation formula becomes a predetermined value while satisfying the constraint condition;
A program for running

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