Grid violation resolution control calculation system, grid violation resolution system, fault calculation system, grid stabilization system, preventive control system, and grid violation resolution control calculation method

Abstract

To perform calculation for robust violation dissolving control against a variable factor in a power system.SOLUTION: A system violation dissolving control calculation system performs calculation for system violation dissolving control to dissolve a system violation in a power system. The system violation dissolving control calculation system includes a constraint condition formulation unit that formulates a constraint condition of an optimization problem for performing calculation for system violation dissolving control on the basis of a model of the power system and the state of the power system, and a variation influence calculation unit that calculates the degree of an influence which the power variation in each bus of the power system exerts on a line power flow in each transmission line of the power system, on the basis of the constraint condition and a variation range indicating the range of power variation in each bus.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a system violation elimination control calculation system, a system violation elimination system, a fault calculation system, a system stabilization system, a preventive control system, and a system violation elimination control calculation method.

Background Art

[0002] In a power system responsible for power transmission, there are an increasing number of factors causing fluctuations, such as power generation from renewable energy. It is known that factors causing fluctuations in a power system significantly affect the power flow of the power system, and there are concerns everywhere that the flow of the power flow becomes complicated. Such complication of the power system is known to induce violations of the power system, such as overloading of transmission equipment, and to complicate the recovery from these violation states. For example, when attempting to eliminate a system violation by changing the output limit of a wind turbine generator, there is a concern that the state of the power system changes before the control result is reflected, and appropriate violation elimination cannot be achieved.

[0003] Regarding such factors causing fluctuations, methods for dealing with fluctuations have been proposed in the field of power systems.

[0004] For example, as an application example to a power generation plan, Patent Document 1 is known. In Patent Document 1, a scenario tree and a Branch-cut-price algorithm are utilized to formulate a power generation plan corresponding to fluctuations.

[0005] Also, Patent Document 2 is known for maintaining the frequency of a power system and eliminating line violations. In Patent Document 2, a method is proposed in which fluctuations are eliminated within a control loop by using partial model predictive control or adaptive control.

[0006] Also, as an example of dealing with assumed failures, which are one of the uncertain factors that occur with low frequency, Patent Document 3 is known. In Patent Document 3, by using a mathematical approach based on the Bi-level decomposition scheme to solve an optimization problem with severe fluctuation factors as constraints, an operating point that can avoid these is calculated.

[0007] Also, as examples of operating without specifying severe failures, Non-Patent Document 1 and Non-Patent Document 2 are known. In Non-Patent Document 1, fluctuations are captured as a distribution and incorporated as a constraint condition when calculating the operating point. Also, in Non-Patent Document 2, the operating margin is regarded as a probability distribution and incorporated into the constraint conditions to probabilistically calculate an optimal operating point.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Non-Patent Documents

[0009]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0010] Fluctuations in the power system tend to increase as the scale of the power system and the factors causing fluctuations increase. Also, since these fluctuations are continuous, it is difficult to appropriately reflect them only with a scenario tree represented in a discrete space as described in Patent Document 1 and Patent Document 3. Also, in a method of executing control according to measurement data as in Patent Document 2, although it can respond to fluctuations, the range of fluctuations that can be responded to is not clear.

[0011] In Non-Patent Document 1 and Non-Patent Document 2, since fluctuations are regarded as a probability distribution, they can exhibit sufficient performance in general operation. However, since they cannot respond to edge cases due to fluctuation components, there is a risk in utilizing the same control for elimination when a system violation occurs.

[0012] The present invention has been made in consideration of the above, and an object thereof is to calculate a violation elimination control that is robust against factors causing fluctuations in the power system.

Means for Solving the Problems

[0013] In order to solve the above-described problems, in one aspect of the present invention, there is provided a system violation elimination control calculation system for calculating system violation elimination control for eliminating system violations in a power system, the system including: a constraint condition formulation unit that formulates constraint conditions of an optimization problem for calculating the system violation elimination control based on a model of the power system and a state of the power system; and a variation influence degree calculation unit that calculates an influence degree of power variation of each bus on a line flow of each transmission line in the power system based on the constraint conditions and a variation range indicating a range of power variation of each bus in the power system.

Advantages of the Invention

[0014] According to the present invention, it is possible to calculate violation elimination control that is robust against factors of variation in a power system. Problems, configurations, and effects other than those described above will be clarified by the description of the embodiments for carrying out the following invention.

Brief Description of the Drawings

[0015]

Figure 1

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Modes for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments are examples for explaining the present invention, and for the sake of clarity of explanation, omissions and simplifications are made as appropriate. The present invention can be implemented in various other forms. Unless otherwise particularly limited, each component may be singular or plural.

[0017] When there are a plurality of components having the same or similar functions, they may be described with the same reference numeral and different subscripts. Also, when it is not necessary to distinguish these plurality of components, the subscripts may be omitted in the description.

[0018] In an embodiment, the processing performed by executing a program may be described. Here, a computer executes a program by a processor (e.g., a CPU (Central Processing Unit), a GPU (Graphics Processing Unit)), and performs the processing defined by the program while using a storage resource (e.g., a memory) and an interface device (e.g., a communication port), etc. Therefore, the subject of the processing performed by executing the program may be the processor. Similarly, the subject of the processing performed by executing the program may be a controller, a device, a system, a computer, or a node having a processor. The subject of the processing performed by executing the program may be an arithmetic unit and may include a dedicated circuit for performing a specific processing. Here, the dedicated circuit is, for example, an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), a CPLD (Complex Programmable Logic Device), a quantum computer, etc.

[0019] The program may be installed in a computer from a program source. The program source may be, for example, a program distribution server or a storage medium readable by a computer. When the program source is a program distribution server, the program distribution server includes a processor and a storage resource for storing the program to be distributed, and the processor of the program distribution server may distribute the program to be distributed to other computers. Also, in an embodiment, two or more programs may be realized as one program, or one program may be realized as two or more programs.

[0020] In the following description, "XXXDB" refers to a database that stores "XXX" which is information (or data), but may also refer to "XXX" itself stored in "XXXDB". A DB (Data Base) is an example of a storage unit.

[0021] In the following description, for example, a symbol with a symbol "~" directly above the symbol "A" is described as "A~".

[0022] [Embodiment 1] In this embodiment, an example of applying the disclosed technology to the control calculation for overload elimination in a power system will be described.

[0023] First, the power system will be described with reference to FIG. 1. FIG. 1 is a diagram showing a configuration example of the power system PS.

[0024] The power system PS is a network mainly composed of power generation equipment, power transmission equipment, and demand respectively, and mainly aims to deliver power to the demand via the power transmission equipment. For the highly reliable operation of the power system PS, the line power flow S needs to strictly comply with the upper limit S max of the line power flow. In FIG. 1, the power generation equipment includes generators G1 to G3 and the wind power generator WF1. The power transmission equipment includes transmission lines PL1 to PL7. The demand includes loads L1 to L3. As shown in FIG. 1, the generators G1 to G3 and the loads L1 to L3 are connected to the buses B1 to B6, and the buses B1 to B6 are connected via the transmission lines PL1 to PL7, thereby constituting the power system PS.

[0025] At this time, the upper limit S max of the line power flow is determined by the voltage stability, frequency stability, transient stability of the power system, and the heat capacity of the power transmission equipment. Since the violation state (overload) where the line power flow S exceeds the upper limit S max of the line power flow affects the reliability of power transmission, which is the main purpose of the power system, it is necessary to eliminate it.

[0026] Overload elimination is achieved by combining means such as transferring the power generation output of the power system, changing the state of transmission equipment, and changing the demand. However, except for transmission equipment, there is a concern that the state of the power system may change before the control of overload elimination is reflected. In FIG. 1, the state change of the power system is indicated by "+ / -". For example, at a bus to which a renewable energy power source or a load is connected, the generated power or the consumed power changes. Even in a power system where such a state change is expected, the purpose of the system of this embodiment is to calculate control that can eliminate overloads with high reliability. Note that in FIG. 1, since the power transmission amount of transmission line PL3 is in an overload state (S > S max !), an example is shown in which the overload is eliminated without unnecessarily affecting other transmission lines by operating the power system.

[0027] Here, with reference to FIG. 2, the configuration of the system violation elimination control calculation system 1 of this embodiment will be described. FIG. 2 is a diagram showing a configuration example of the system violation elimination control calculation system 1 according to Embodiment 1. FIG. 3 is a diagram showing a configuration example of the hardware of the system violation elimination control calculation system 1 according to Embodiment 1.

[0028] The system violation elimination control calculation system 1 is a system configured by a computer 10 (FIG. 3). The functional configuration of the system violation elimination control calculation system 1 shown in FIG. 2 is realized by using each hardware element of the computer 10 shown in FIG. 3. The computer 10 includes a memory 101 which is a main storage device, an arithmetic means 102 which is a processor such as a CPU or a GPU, and an input means 103 such as a keyboard, a mouse, and a touch panel. Further, the computer 10 includes an output means 104 including a GPU, a monitor, and a communication interface, and a database DB which is an external storage device. FIG. 2 represents each processing function unit realized by the execution of a program by the data on the memory 101 and the database DB and the arithmetic means 102, and the output means 104 for displaying the result via the GPU and the monitor, respectively, by each database and each processing block.

[0029] Returning to the description of FIG. 2. The system violation elimination control calculation system 1 includes a power system model DB1 for storing a power system model, a power system state DB2 for storing a power system state, and a variation range DB3 for storing a variation range. Further, the system violation elimination control calculation system 1 includes a variation influence degree DB4 for storing a variation influence degree, a system violation elimination control DB5 for storing a system violation elimination control, and a system violation elimination possibility DB6 for storing whether system violation elimination is possible. At least any one of the power system model DB1, the power system state DB2, the variation range DB3, the variation influence degree DB4, the system violation elimination control DB5, and the system violation elimination possibility DB6 may be an external device connected to the system violation elimination control calculation system 1.

[0030] Further, the system violation elimination control calculation system 1 has, as processing functions, a constraint condition formulation unit 12, a variation influence degree calculation unit 13, a system violation elimination control calculation unit 14, and a system violation elimination control evaluation unit 15. Also, the system violation elimination control calculation system 1 has an output unit 16 such as a display and a speaker. The output unit 16 may be an external device connected to the system violation elimination control calculation system 1.

[0031] The constraint condition formulation unit 12 formulates and outputs power system constraints by taking the power system model DB1 and the power system state DB2 as inputs. The variation influence degree calculation unit 13 calculates and outputs a variation influence degree by taking the power system constraints output by the constraint condition formulation unit 12 and the variation range DB3 as inputs. The calculated variation influence degree is stored in the variation influence degree DB4.

[0032] The system violation elimination control calculation unit 14 calculates and outputs a system violation elimination control by taking the power system constraints output by the constraint condition formulation unit 12 and the variation influence degree DB4 as inputs. The calculated system violation elimination control is stored in the system violation elimination control DB5. The system violation elimination control evaluation unit 15 calculates and outputs the system violation elimination possibility DB6 by taking the power system model DB1, the power system state DB2, and the system violation elimination control DB5 as inputs. The output unit 16 displays these inputs and outputs. The detailed flow of each function will be described later.

[0033] Here, various input data will be described. The power system model DB1 is data that stores the impedance of the power system PS, connection configuration, upper and lower limits of generator output, load characteristics, generator models, etc. The power system model DB1 includes one or more of the data used for power flow calculation assuming a constant frequency of the power system, and the data used for dynamic calculation on the premise that the frequency can vary.

[0034] The power system state DB2 is data representing the state of the power system, and has information such as the voltage and phase of each bus calculated by state estimation of the power system, and the power flow of each transmission line calculated by power flow calculation.

[0035] The variation range DB3 is the range of bus power that can vary uncertainly in the power system, and can be expressed, for example, by Equation (1).

[0036]

Equation

[0037] Here, N is the number of buses, P~ is a vector representing the power variation of all buses, P i ~ is the power variation of bus i, P i ~ min and P i ~ max are the lower and upper limits of the power variation P i ~ of bus i. P i ~ min and P i ~ max are stored in the variation range DB3.

[0038] In the power system PS of FIG. 1, the part marked with "+ / -" corresponds to the variation range DB3. For example, at the bus connected to the renewable energy power source, since the power variation is large, it is conceivable to set a large variation range, etc. The setting of the variation range will be described later.

[0039] Next, various output data will be described. The variation influence degree DB4 represents the influence of the variation range on the power system targeted. As an example, it is the influence of the variation range on each transmission line. Mathematically, for example, it can be expressed by Equation (2).

[0040]

Number

[0041] Here, S l ~ is the influence of the power flow variation on the transmission line l due to the variation range DB3, and S l ~ min and S l ~ max are the upper and lower limits of the influence of the power flow variation on the transmission line l due to the variation range DB3.

[0042] The system violation elimination control DB5 indicates, for example, the amount of transfer of power generation equipment and loads in the power system and the change in system configuration for eliminating system violations. The amount of transfer of power generation equipment and loads in the power system can be expressed, for example, by Equation (3).

[0043]

Number

[0044] Here, ΔP i is the amount of change in active power to bus i. In addition to the amount of change in active power, it is also possible to eliminate violations by changing the system configuration.

[0045] The system violation elimination possibility DB6 is the result of determining the possibility of eliminating system violations by system violation elimination control. When system violation elimination is not possible, the margin of the system violation amount until violation elimination may be shown.

[0046] Next, the overall processing flow of this embodiment will be described with reference to FIG. 4. FIG. 4 is a flowchart showing an example of the overall processing of the system violation elimination control calculation system 1 according to Embodiment 1.

[0047] In step S11, the system violation elimination control calculation system 1 reads the power system model DB1, the power system state DB2, and the variation range DB3. In step S12, the constraint condition formulation unit 12 formulates the power system model DB1 and the power system state DB2 as constraint conditions for the violation elimination logic.

[0048] In step S13, the variation influence degree calculation unit 13 calculates a variation influence degree DB4 of the power variation of each bus on the power system based on the constraint conditions (power system constraints) calculated in step S12 and the variation range DB3. In step S14, the system violation elimination control calculation unit 14 calculates a system violation elimination control DB5 based on the power system constraints and the variation influence degree DB4. In step S15, the system violation elimination control evaluation unit 15 evaluates the system violation elimination control DB5. In step S16, the evaluation result of step S15 is output to the output unit 16.

[0049] By using such a series of controls, the user can obtain the variation influence degree, the system violation elimination control, and the possibility of system violation elimination for the input power system model, power system state, and variation range.

[0050] Next, taking the power system PS shown in FIG. 1 as a specific example, the details of each of steps S11 to S16 in FIG. 4 will be described.

[0051] The power system model DB1 of this embodiment is, for example, a model of the power system PS illustrated in FIG. 1. The power system state DB2 is, for example, the state of the power system PS illustrated in FIG. 1. For this state, in this embodiment, state changes of the variation range DB3 of ±5 MW are assumed for buses B1, B5, and B6. In step S11, such input data is acquired from the user or another system.

[0052] In step S12, the power system state DB2 is formulated as a constraint condition for the violation elimination logic. At this time, the constraint condition is created so that the constraints of the power system are maintained by the violation elimination control under the influence of the variation range DB3. The constraint condition can be expressed by, for example, Equation (4) as an example.

[0053]

Number

[0054] Here, S l init is the apparent power of the transmission line identified by index l in the power system state DB2. A is the sensitivity matrix representing the change amount of each transmission line in the change of the active power of each bus. S l max , S l min are the upper and lower limits of the line power flow of the transmission line identified by index l.

[0055] Here, "ΔP + AP~" in the middle of Equation (4) represents the sum of the control amount ΔP by the violation elimination control and the influence on the line power flow due to the change in the active power of the bus. At this time, the sensitivity coefficient A can be calculated by repeating the power flow calculation for the change of each element of the power system model DB1, or by using the sensitivity coefficient (PTDF: Power Transfer Distribution Factor) that can be calculated by the direct current method (Direct Current Power Flow) of the power system. If Equation (4) is satisfied, at least in the linearized region, even when there is a change in the active power of the bus, the overload (a kind of violation) of the power system is eliminated. Also, in this way, by defining the influence of the fluctuation component as a constraint in the violation elimination control calculation, it can be applied to various violation elimination control calculation logics.

[0056] Next, the details of step S13 will be described. First, when the control is not executed, it can be seen that the constraint equation of Equation (4) is determined by the variation range as in Equation (5).

[0057]

Number

[0058] At this time, since the fluctuation P~ is different from the decision variable of the optimization problem and does not necessarily take a value cooperative with the optimization, in this state, it is difficult to evaluate the influence of the fluctuation range. Therefore, in the present embodiment, the linear relationship of Expression (5) is utilized to separate the upper and lower limits of the influence on the transmission line l by the fluctuation range DB3 due to the change in the active power of the bus.

[0059]

Number

[0060] For example, the severe lower limit of the influence due to the fluctuation range can be solved through the optimization problem of Expression (7).

[0061]

Number

[0062] Here, as shown in Expression (7), it is desirable that the sum of the power fluctuations P i ~ of the active power of the bus is zero. This is an important premise in the power flow calculation of the power system. If this premise collapses, it will affect the power flow calculation itself.

[0063] Similarly, the severe upper limit of the influence due to the fluctuation range can be solved through the optimization problem of Expression (7).

[0064]

Number

[0065] By separating the constraint equations of the power system state into an optimization problem with the power flow variation of each transmission line due to the influence of the active power variation of the bus as the objective function, the influence of the assumed variation range can be calculated. When the overload is the target, the influence of this variation range can be expressed by Equation (9).

[0066]

Number

[0067] In this way, by solving the optimization problem with the power flow variation separated from the constraint conditions as the objective function, the degree of influence due to the variation of the bus power is calculated, so a general-purpose degree of influence that does not depend on individual optimization problems is calculated. That is, the degree of influence due to the variation is calculated by solving the set of individual optimization calculations for calculating the degree of influence due to the variation. Therefore, the degree of influence calculated in this way can be applied to various algorithms for power system violation elimination control calculations.

[0068] Next, the details of step S14 will be described. In step S14, in order to eliminate the violation of the power system, for example, an optimization problem of minimizing the amount of active power change to each bus is used. As an example, the solution of the optimization problem of Equation (10) is used.

[0069]

Number

[0070] Note that although Equation (10) is expressed as an absolute value minimization problem, it may be reformulated as a linear programming method and solved. In any case, the calculated solution is ΔP, which is the control amount for eliminating the violation of the target power system. As long as the solution satisfies the constraints of Equation (10), a control amount robust to the assumed variation can be calculated.

[0071] Here, an example of robust control will be described with reference to FIGS. 5 and 6. FIG. 5 is an explanatory diagram of an operation example of a system violation elimination control calculation system according to the prior art. FIG. 6 is an explanatory diagram of an operation example of a system violation elimination control calculation system according to Embodiment 1.

[0072] First, consider the case of performing control without considering the variation range DB3 of the prior art. As shown in FIG. 5, control is performed such that the output of the wind power generator WF1 is 100 → 104 MW, the output of the generator G1 is 100 → 99 MW, the output of the generator G2 is 100 → 104 MW, the output of the generator G3 is 50 → 48 MW, and the consumption of the load L1 is 150 → 153 MW. Since the variation range DB3 is not considered, there is no problem when the system state does not change. However, when the system state changes, as shown in FIG. 5, although the violation of the transmission line PL3 (FIG. 1) is resolved, a violation is induced in another transmission line (transmission line PL5).

[0073] Next, consider the case of performing control considering the variation range DB3 of the present embodiment. As shown in FIG. 6, the control of the output of the generator G1 being 100 → 101 M and the output of the generator G2 being 100 → 102 MW is different from the prior art shown in FIG. 5. However, since the variation range DB3 is considered, even when the system state changes, the violation can be resolved.

[0074] Returning to the description of FIG. 4. In step S15, it is confirmed whether the violation of the system state can be resolved with the control amount calculated in step S14. At this time, after reflecting the control amount calculated in step S14 in the power system model, it is confirmed by power flow calculation. If the violation of the system state can be resolved with the control amount calculated in step S14, for example, "OK (resolvable)" is recorded in the system violation resolution availability DB6. Also, if the violation of the system state cannot be resolved with the control amount calculated in step S14, for example, "NG (unresolvable)" is recorded in the system violation resolution availability DB6. If the violation of the system state cannot be resolved with the control amount calculated in step S14, the margin until the violation is resolved may be recorded.

[0075] Note that the system violation elimination control calculation unit 14 may calculate system violation elimination control without considering the variation range DB3. In this case, the system violation elimination control evaluation unit 15 reflects the control amount calculated without considering the variation range DB3 in the power system model and then checks it by power flow calculation. If the violation of the system state can be eliminated with the control amount calculated without considering the variation range DB3, for example, "OK (eliminable)" is recorded in the system violation elimination possibility DB6. Also, if the violation of the system state cannot be eliminated with the control amount calculated without considering the variation range DB3, for example, "NG (ineliminable)" is recorded in the system violation elimination possibility DB6. If the violation of the system state cannot be eliminated with the control amount calculated without considering the variation range DB3, the margin until the violation is eliminated may be recorded.

[0076] The system violation elimination control evaluation unit 15 evaluates one or more of the cases with robustness (considering the variation range DB3) and the cases without robustness (not considering the variation range DB3). By using both the evaluation with robustness and the evaluation without robustness, the necessity of robustness and the effect of control can be evaluated.

[0077] In step S16, the calculation result of step S15 is displayed. Here, an example of the display will be described with reference to FIG. 7. FIG. 7 is a diagram showing an example of the screen display 16d displayed on the output unit 16 of the system violation elimination control calculation system 1 according to Embodiment 1.

[0078] The power system model and the power system state are shown in the display 16d1 on the output unit 16, and the state of the power system to be analyzed can be confirmed. Also, the variation range DB3 used in the analysis is shown in the display 16d2, the system violation control for this variation range DB3 is shown in the display 16d3, the variation influence degree is shown in the display 16d4, and the system violation elimination possibility is shown in the display 16d5, respectively. By displaying in this way, the user can confirm whether robust violation control against the variation range is possible and utilize it for system control.

[0079] By using the system violation elimination control calculation system 1 of this embodiment, it is possible to calculate a robust control that can eliminate violations against uncertain influences due to changes in the state of the power system.

[0080] [Embodiment 2] Now, in Embodiment 1, as a result of the fluctuation range DB3 being too wide, it may be difficult to calculate the system violation elimination control calculation. In this embodiment, as an example of avoiding the difficulty of the system violation elimination control calculation, after identifying the bottleneck transmission line, the objective function of the overload violation control is solved by solving the problem of minimizing the violation degree of the bottleneck transmission line, thereby calculating the solution.

[0081] [Number]

[0082] In Equation (11), "l" is the index of the transmission line identified as the bottleneck, and S l max , S l min are the upper and lower limits of the line flow of the corresponding transmission line, and ΔS l ~ max , ΔS l ~ min are the upper and lower limits of the influence on the line flow of the corresponding transmission line due to the fluctuation range DB3.

[0083] Also, as a modification, the system violation control may be calculated after narrowing the fluctuation range based on a predetermined control. As another modification, by assigning priorities to the transmission lines, the constraints of the fluctuation range can be partially relaxed.

[0084] That is, when the system violation elimination control calculation unit 14 (Figure 2) cannot calculate the system violation elimination control within a predetermined time or within a predetermined number of trials, it solves an optimization problem in which the objective function, constraint conditions, and the fluctuation range DB3 serving as the basis for the influence degree are relaxed. As a result, the system violation elimination control calculation unit 14 may be able to calculate a control that reduces or minimizes the system violation.

[0085] [Embodiment 3] In this embodiment, an example of the variation range calculation unit 2 that calculates the variation range DB3 will be described.

[0086] The system violation resolution control calculation system 1 of Embodiment 1 is realized by setting a fixed margin in the constraint formula of the power system in order to calculate the system violation resolution control corresponding to the variation range DB3. However, setting an unnecessarily large margin in the variation range DB3 may result in excessive control. Therefore, in this embodiment, the variation range calculation unit 2 that calculates an appropriate variation range DB3 so as not to cause excessive control will be described.

[0087] The variation range calculation unit 2 will be described with reference to FIG. 8. FIG. 8 is a diagram showing a configuration example of the variation range calculation unit 2 according to Embodiment 3.

[0088] The variation range calculation unit 2 includes a system state performance data DB7 that stores past system states, a variation range calculation parameter DB8, a range calculation unit 21, and the variation range DB3. The system state performance data DB7 stores data such as power generation performance, configuration performance, and load performance in the power system. The variation range calculation parameter DB8 stores, for example, the specified range for calculating the system state performance, the calculation interval of the variation range, the severity of the variation range, and the like. Here, the calculation interval of the variation range is an interval for calculating each distribution. For example, when it is a time series range of 10 seconds, the variation in power is calculated based on the beginning of the 10 seconds.

[0089] The detailed flow of the variation range calculation unit 2 will be described with reference to FIG. 9. FIG. 9 is a flowchart showing an example of the variation range calculation process of the variation range calculation unit 2 according to Embodiment 3.

[0090] First, in step S21, the range calculation unit 21 of the fluctuation range calculation unit 2 reads the fluctuation range calculation parameter DB8. Next, in step S22, the range calculation unit 21 reads data within the range specified by the fluctuation range parameter read in step S21 from the system state performance data DB7. Next, in step S23, the range calculation unit 21 calculates the range of the influence degree of fluctuation for each bus for each fluctuation interval. Next, in step S24, the range calculation unit 21 regards the range of the influence degree of fluctuation calculated in step S23 as a distribution, and determines the upper and lower limits of the fluctuation range based on the severity of this fluctuation range. Next, in step S25, the range calculation unit 21 outputs the fluctuation range DB3.

[0091] Here, steps S23 and S24 will be described with reference to FIG. 10. FIG. 10 is an explanatory diagram of range calculation in the fluctuation range calculation unit 2 according to Embodiment 3.

[0092] The fluctuation range of the power of each bus calculated based on the fluctuation range can be represented by a certain distribution (for example, a normal distribution). At this time, in the distribution within the calculation range, 1σ, 2σ, 3σ, etc. based on the standard deviation σ are obtained as the severity. Here, the upper and lower limits corresponding to the severity are set as the fluctuation range. For buses with clear output upper and lower limits such as renewable energy, the fluctuation range may be calculated for each output of the renewable energy.

[0093] In addition, when the fluctuation range of the power of each bus cannot be represented by a normal distribution, a parameter equivalent to the severity may be substituted. For example, in the distribution, the upper and lower limits including 68.27% of the data above and below the median (Median) equivalent to 1σ may be substituted.

[0094] [Embodiment 4] In this embodiment, an example in which the system violation resolution control calculation system 1 of Embodiment 1 is coordinated with various power system systems will be described.

[0095] Here, with reference to FIG. 11, the overall configuration of the system violation resolution system 3 will be described. FIG. 11 is a diagram showing a configuration example of the system violation resolution system 3 according to Embodiment 4. The system violation resolution system 3 includes the system violation resolution control calculation system 1 of Embodiment 1 or 2, a variation range DB 3, a calculation interval DB 9, and a calculation management unit 31. The variation range DB 3 and the calculation interval DB 9 may be external devices connected to the system violation resolution system 3.

[0096] The calculation management unit 31 manages calculations using the calculation interval and the variation range as inputs. The system violation resolution control calculation system 1 executes the calculation of system violation resolution control with the calculation result of the calculation management unit 31, the power system model DB 1 of the power system model management system 8, and the power system state DB 2 of the power system state monitoring system 9 as inputs.

[0097] Here, the calculation management unit 31 can execute the system violation resolution control calculation system 1 at a predetermined cycle by setting the calculation interval and the variation range DB 3. This is particularly important in an online calculation system, and if the variation range calculation unit 2 of Embodiment 3 is used, it can always correspond to the latest variation range DB 3. With this system violation resolution system 3, the screen display 16d of the output unit 16 in FIG. 7 can be continuously updated at a constant cycle.

[0098] Also, when the variation range DB 3 is changed, by executing calculations with the changed variation range DB 3, it is possible to take measures such as changing the variation range DB 3 according to the time zone.

[0099] By using the system violation resolution system 3 of this embodiment, the user can repeatedly execute calculations with the system violation resolution control calculation system 1 of Embodiment 1 or 2 as part of an online system, and can always calculate a robust control command even under the uncertainty assumed within the range of the variation range DB 3. Also, by taking the form of inputting the variation range DB 3 to the system violation resolution control calculation system 1 at a predetermined cycle via the calculation management unit 31 and obtaining the calculation result, it becomes possible to reflect the latest variation factors based on the latest data.

[0100] [Embodiment 5] In this embodiment, a case where the system violation elimination control calculation system 1 of Embodiment 1 or 2 is applied to a system stabilization system (protection system) will be described.

[0101] Here, with reference to FIG. 12, the overall configuration of this embodiment will be described. FIG. 12 is a diagram showing a configuration example of a fault calculation system and a system stabilization system (protection system) 5 according to Embodiment 6.

[0102] The system stabilization system 5 includes a fault calculation system 4, a remote control unit 51, and a fault case determination unit 52. The fault calculation system 4 includes the system violation elimination control calculation system 1 described in Embodiment 1 or 2, a fault calculation management unit 41, a fault case DB 10, and a fault calculation result DB 11. The system stabilization system 5 is connected to a power system model management system 8, a power system state monitoring system 9, and a control target 100 such as a generator, a transmission device, or a load.

[0103] The system stabilization system 5 utilizes the system violation elimination control calculation system 1 of Embodiment 1 or 2 as an engine for fault calculation, and is a system that stabilizes the power system by the fault calculation management unit 41 and the remote control unit 51.

[0104] The fault calculation management unit 41 takes as inputs the power system model DB 1 of the power system model management system 8, the power system state DB 2 of the power system state monitoring system 9, and the fault case DB 10, and simulates and calculates the power system state corresponding to the fault case of the power system. The fault case DB 10 is list information enumerating simulated fault cases that simulate assumed faults.

[0105] The fault calculation management unit 41 can calculate the system violation elimination control for each fault case by inputting each of the power system states simulated for each fault case into the system violation elimination control calculation system 1. At this time, the above-described variation range may be changed for each fault case.

[0106] After the system violation resolution control for each failure case is calculated, the failure calculation management unit 41 stores, as the failure calculation result DB 11, by associating the state of the failure case with the system violation resolution control for each failure case. When the power system state DB 2 corresponds to a failure, the failure case determination unit 52 causes the remote control unit 51 to refer to the failure calculation result DB 11, acquires a control command corresponding to the corresponding failure item, and outputs it to the control target 100. By using such a configuration, the system stabilization system 5 can stabilize the power system with robust violation resolution control.

[0107] [Embodiment 6] In this embodiment, a case where the system violation resolution control calculation system 1 of Embodiment 1 or 2 is applied to a preventive control system that calculates an operation point at which violations during a failure can be resolved will be described. FIG. 13 is a diagram showing a configuration example of a preventive control system 6 and a system operation system 7 according to Embodiment 6. The system operation system 7 includes a preventive control system 6 and a remote operation control unit 71. The preventive control system 6 includes the system violation resolution control calculation system 1 of Embodiment 1 or 2 and a preventive control operation point calculation unit 61.

[0108] When the transmission line K is released, it is generally known that the amount of change in the power flow of the transmission line L can be calculated by the line outage distribution factor (LODF). Here, the LODF can be calculated from the sensitivity coefficient A described above. The power flow P of the transmission line l after the release of the transmission line k l is known to be expressed by Equation (12).

[0109] [Equation]

[0110] Here, P k 0 is the pre-fault power flow of the transmission line k, P l 0 is the pre-fault power flow of the transmission line l, and LODF l,k is the LODF of the transmission line l when the transmission line k is released. Here, LODFk When one or more power transmission lines k are opened, if the LODF for all the power transmission lines that are not opened is considered, the power flow constraint equation in the fault case of the target power transmission line can be expressed as in Equation (13). The preventive control operation point calculation unit 61 acquires Equation (10) from the system violation elimination control calculation system 1 and generates Equation (13).

[0111]

Number

[0112] Here, the opening of the power transmission line k is regarded as a fault of the power transmission line k, and it is called the fault case k. The fault case k is a subset of all the fault cases K. When the preventive control operation point calculation unit 61 can calculate a solution k that satisfies the constraint of Equation (13), it determines that there is a possibility of eliminating the violation state of the fault case k. In addition, the preventive control operation point calculation unit 61 calculates the operation point (power transmission line) in the state where the system violation has been eliminated even if a fault occurs in a certain power transmission line k from the complement of the set of solutions k that satisfy the constraint of Equation (13).

[0113] Equation (13) is obtained by replacing the first power flow constraint condition of Equation (10) with an equation using the LODF. By using Equation (13), it may be possible to roughly determine the possibility of eliminating the constraint violation state and the operation point in the violation elimination state from the power flow constraint conditions before solving the optimization problem.

[0114] The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Also, as long as there is no contradiction, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Also, for a part of the configuration of each embodiment, addition, deletion, replacement, integration, or dispersion of the configuration is possible. Also, the configurations and processes shown in the embodiments can be appropriately dispersed, integrated, or replaced based on processing efficiency or implementation efficiency.

Explanation of Symbols

[0115] 1: System Violation Resolution Control Calculation System, 3: System Violation Resolution System, 4: Fault Calculation System, 5: System Stabilization System, 10: Computer.

Claims

1. A system violation elimination control calculation system that calculates system violation elimination control for eliminating system violations in a power system, a constraint formulation unit that formulates constraints for an optimization problem for calculating the system violation elimination control based on the model of the power system and the state of the power system; a variation influence degree calculation unit that calculates the influence degree of the power variation of each bus on the line power flow of each transmission line in the power system based on the constraints and the variation range indicating the range of power variation of each bus in the power system A system violation elimination control calculation system characterized by comprising.

2. The system violation elimination control calculation system according to claim 1, wherein the variation influence degree calculation unit calculates the influence degree by solving an optimization problem having, as an objective function, the power flow variation exerted by the power variation of each bus on the line power flow of each transmission line in the power system. A system violation elimination control calculation system characterized by this.

3. The system violation elimination control calculation system according to claim 1, a system violation elimination control calculation unit that calculates the system violation elimination control by solving the optimization problem based on the influence degree and the constraints. A system violation elimination control calculation system characterized by comprising this.

4. The system violation elimination control calculation system according to claim 3, a system violation elimination control evaluation unit that evaluates whether or not the system violation can be eliminated when the influence degree is taken into account based on the model of the power system, the state of the power system, and the system violation elimination control calculated by the system violation elimination control calculation unit. A system violation elimination control calculation system characterized by comprising this.

5. The system violation elimination control calculation system according to claim 4, wherein the system violation elimination control calculation unit calculates a solution to the optimization problem without considering the influence degree, and the system violation elimination control evaluation unit evaluates whether or not the system violation can be eliminated without considering the influence degree based on the model of the power system, the state of the power system, and the solution calculated by the system violation elimination control calculation unit. A system violation elimination control calculation system characterized by this.

6. The system violation elimination control calculation system according to claim 5, outputting at least any one of the variation range, the influence degree, the system violation elimination control, and the evaluation result of whether or not the elimination is possible when the influence degree is considered and the evaluation result of whether or not the elimination is possible when the influence degree is not considered from an output unit. A system violation elimination control calculation system characterized by this.

7. A system violation elimination control calculation system according to claim 1, a variation range calculation unit that calculates the variation range based on past performance data of the state of the power system The system violation elimination control calculation system is characterized by having.

8. A system violation elimination control calculation system according to claim 7, wherein the variation range calculation unit reads the performance data within a specified range, calculates the variation range of the power of each bus for each predetermined interval, and determines the upper and lower limits of the variation range based on the severity of the variation range when the variation range is represented by a predetermined distribution The system violation elimination control calculation system is characterized by the above.

9. A system violation elimination control calculation system according to claim 3, wherein the system violation elimination control calculation unit when the system violation elimination control cannot be calculated, solves an optimization problem with a relaxed objective function, constraint condition, or influence degree of the optimization problem, and calculates control for reducing or minimizing the system violation The system violation elimination control calculation system is characterized by the above.

10. A system violation elimination control calculation system according to claim 3, and a calculation management unit that manages the execution of the calculation of the system violation elimination control by the system violation elimination control calculation system The system violation elimination system is characterized by having.

11. A system violation elimination control calculation system according to claim 3, and a calculation management unit that inputs a simulated fault case simulating a fault of the power system to the system violation elimination control calculation system and manages the execution of the calculation of the system violation elimination control for eliminating the system violation in the simulated fault case by the system violation elimination control calculation system, and a storage unit that stores the system violation elimination control calculated for each simulated fault case in association with each simulated fault case The fault calculation system is characterized by having.

12. A fault calculation system according to claim 11, and a fault case determination unit that determines which fault case the state of the power system corresponds to, and a remote control unit that refers to the storage unit, acquires the system violation elimination control associated with the simulated fault case corresponding to the fault case determined by the fault case determination unit, and outputs a control command to a control target based on the system violation elimination control The system stabilization system is characterized by having.

13. A system violation elimination control calculation system according to claim 1, and Replace the power flow constraint condition among the above-mentioned constraint conditions with a constraint condition expressed using the opening sensitivity when the transmission lines of the power system are opened. When there exists a transmission line that satisfies this constraint condition, it is determined that there is a possibility of eliminating the system violation in the event of a fault in this transmission line, and a preventive control operating point calculation unit calculates the operating point of the power system in the state where the system violation has been eliminated. A preventive control system characterized by having the above.

14. A method for calculating system violation elimination control performed by a system violation elimination control calculation system that calculates system violation elimination control for eliminating system violations in a power system, A constraint condition formulation step of formulating constraint conditions for an optimization problem for calculating the system violation elimination control based on the model of the power system and the state of the power system; A variation influence degree calculation step of calculating the influence degree that the power variation of each bus of the power system has on the line flow of each transmission line of the power system based on the constraint conditions and the variation range indicating the range of power variation of each bus of the power system A method for calculating system violation elimination control, characterized by having the above.

15. The method for calculating system violation elimination control according to claim 14, wherein in the variation influence degree calculation step, the influence degree is calculated by solving an optimization problem having, as an objective function, the power flow variation that the power variation of each bus has on the line flow of each transmission line of the power system A method for calculating system violation elimination control, characterized by the above.

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