JP6666290B2 - Power system reduced model creation device and power system reduced model creation method - Google Patents

Description

  The present embodiment relates to a power system reduced model creation device and a power system reduced model creation method for creating a reduced system model of a power system.

  A power system model is used for synchronous stability analysis at the time of a power system accident and for stabilization calculation of a system stabilization system. The power system model is information that models characteristics of a generator and the like in the power system and a connection state with the system. As the power system becomes larger and more complicated, the power system model becomes larger and more complicated. 2. Description of the Related Art There is known a power system contraction model creation device that creates a power system contraction model in which an original power system model (original system model) is partially simplified in order to reduce the processing load and analysis time.

JP 2012-114996 A JP 2015-53847 A

Electric Cooperative Research Vol.34 No.5 "External System Reduction Method Considering Spectrum of Power Fluctuation Waveform", IEEJ Transactions on Power and Energy, Vol. 135, No. 4, pp. 241-250 "System Reduction Method Using Differential Evolution", Institute of Electrical Engineers of Japan, PSE-15-170 "System Reduction Method Considering Stabilized Control Amount", IEEJ National Convention 2016, 6-126

  The power system reduction model is required to reflect the characteristics of the original system model as closely as possible. The existing reduction method is a two-load method that mathematically calculates the parameters of the reduced system according to the system to be reduced, and matches the characteristics of the original system model with the characteristics such as the tidal current and voltage at the interconnection point at the time of the accident. There is a method of matching the dynamic characteristics after the accident in addition to the characteristics at the time of the accident with the original system model. By combining the dynamic characteristics, the stability characteristics of the original system model can be accurately reflected on the power system reduced model.

  However, the conventional power system contraction model cannot be said to have a sufficiently reduced power control error with the original system. If there is an error in the amount of control required for stabilization between the power system contraction model and the original system model, sufficient system stabilization cannot be performed. An error in the amount of power control between the power system contraction model and the original system model leads, for example, to excessive power control in which the generator is cut off more than necessary, leading to a problem that a cost increase until restoration occurs. In addition, the above-mentioned error leads to a shortage of power in which it is impossible to stably shut off the generator, leading to a problem that the system cannot be stabilized. In the case of under-power control, there is a possibility that large-scale power outages may occur without maintaining the synchronization stability of the system, so it is essential that the power system reduction model be formulated to avoid under-power control.

  The power system contraction model in the prior art is to reduce the power control error for a specific accident of a specific system cross section, but in consideration of actual operation, a plurality of system cross sections that change every moment and It is necessary to keep the control error low for multiple accidents. As a measure to reduce the power control error for multiple system sections and multiple accidents, a power system reduction model is formulated for each combination of multiple system sections and multiple accidents, and power is reduced according to the system section and the accident. A method of switching the system reduction model can be considered. However, the method of switching the power system reduction model according to the system cross section and the accident requires a huge reduction model consisting of multiple system cross sections and multiple accidents. There was a problem about whether it was difficult to switch models.

  This embodiment can reduce the power control error, and can reduce the data amount of the parameter related to the power system reduction model for a combination of a plurality of system sections and a plurality of accidents that are assumed in advance. It is another object of the present invention to provide a power system reduced model creation device and a power system reduced model creation method that do not require switching of a power system reduced model for a system section.

The power system reduced model creation device of the present embodiment has the following configuration.
(1) A reduced model creation unit that creates a reduced system model from an original system model of a power system.
(2) A reduced parameter tuning unit for adjusting reduced parameters of the reduced system model having the following.
(2-1) A tidal section data setting unit for setting arbitrary tidal section data.
(2-2) An assumed accident case setting unit for setting an unstable accident case corresponding to the tidal current data set by the tidal current data setting unit.
(2-3) In the unstable accident case set by the assumed accident case setting unit, a stability that stores a source system stabilization control amount which is a minimum control amount required for stabilization of the source system model. Control amount storage unit.
(2-4) Fluctuation of the original system model when the stabilization control is performed with the reference control amount that is equal to or more than the original system stabilization control amount stored in the stabilization control amount storage unit in the unstable accident case Original system fluctuation calculation unit that calculates the waveform.
(2-5) A reduced system model when the stabilization control is performed with the reference control amount that is equal to or more than the original system stabilization control amount stored in the stabilization control amount storage unit in the unstable accident case. Reduced system fluctuation calculation unit that calculates the fluctuation waveform of the system.
(2-6) calculating a difference between the oscillation waveform of the original system model calculated by the original system oscillation calculation unit and the oscillation waveform of the reduced system model calculated by the reduced system oscillation calculation unit. Difference calculation unit.
(2-7) A reduced parameter estimator for estimating the reduced parameter so as to minimize the difference calculated by the difference calculator, wherein the reduced parameter estimator comprises: A plurality of the reduced system models are created with respect to the plurality of tidal current cross-section data set according to the above, and the plurality of the unstable accident cases set by the assumed accident case setting unit corresponding to the plurality of tidal current cross-sectional data. For the combination of the above, the reduction parameter that minimizes the sum of the difference between the fluctuation waveform of the original system model and the fluctuation waveform of the reduced system model is calculated.
Further, a method for creating a reduced power system model having means corresponding to the above is also an aspect of the present embodiment.

FIG. 1 is a block diagram showing an electric power system contracted model creation device according to a first embodiment. FIG. 2 is a block diagram illustrating a difference calculation unit of the power system contracted model creation device according to the first embodiment. FIG. 2 is a block diagram showing a reduced parameter estimating unit of the power system reduced model creation device according to the first embodiment; The figure which shows the flow of a process of the electric power system contracted model creation apparatus concerning 1st Embodiment. The figure which shows the flow of process S13 of the electric power system contracted model creation apparatus concerning 1st Embodiment. Example of reduced system model Diagram showing an example of created optimization parameters Diagram showing an example of a control procedure of AVR parameters The figure which shows an example of the control procedure of PSS parameter The figure which shows the flow of process S14 of the electric power system contracted model creation apparatus concerning 1st Embodiment. Diagram showing test vector generation procedure The figure which shows the flow of the processing of the objective function calculation in processing S13 and processing S14. Information required for updating the reduced model for each section Diagram showing the relationship between α, β, and T Diagram showing an example of set values of α, β, and T The figure which shows the flow of the objective function calculation processing concerning 2nd Embodiment (with control amount adjustment) The figure which shows the flow of the electric power control adjustment processing of the objective function calculation processing concerning 2nd Embodiment.

[1. First Embodiment]
[1-1. Constitution]
As an example of the present embodiment, a power system contraction model creation device will be described with reference to FIG. The power system contracted model creation device is configured by a computer.

(1) Overall Configuration of System The power system reduced model creation device 1 includes a reduced model creation unit 11 and a reduced parameter tuning unit 12. The contracted model creation unit 11 and the contracted parameter tuning unit 12 are configured by an operation unit or a software module in a computer.

  Further, the power system reduced model creation device 1 includes an original system model storage unit 21, a reduced system model storage unit 22, a power flow section data storage unit 23, an accident case storage unit 24, a setting storage unit 25, and a stabilization control amount. It has a storage unit 26 and a constraint condition storage unit 27. Each of the storage units 21 to 27 is configured by a storage medium such as a conductive memory or a hard disk, and is arranged in a computer.

  Further, the power system contracted model creation device 1 includes an input unit 30 and an output unit 40. The input unit 30 and the output unit 40 are configured by I / O units provided in the computer.

  The input unit 30 includes a keyboard, a mouse, a touch panel, and a communication interface. The touch panel may be configured on a display device. The input unit 30 receives various data stored in the original system model storage unit 21, the tidal section data storage unit 23, the accident case storage unit 24, the stabilization control amount storage unit 26, and the constraint condition storage unit 27.

  The output unit 40 includes a display device, a printer, and a communication interface. The output unit 40 outputs information to be processed by the power system reduced model creation device 1 such as an original system model, a reduced system model, a power flow cross section, an assumed accident case, a stability limit power flow, a difference, and a constant, a calculation result, and the like. Output to the user.

  The original system model storage unit 21 is a storage unit that stores the original system model input from the input unit 30. The original system model storage unit 21 outputs the stored original system model to the reduced model creation unit 11.

  The reduced model creation unit 11 is a processing unit that creates a basic configuration of a reduced system model obtained by reducing the original system model based on the original system model stored in the original system model storage unit 21. The original system model is information that models a power system to be reduced. The original system model is configured by, for example, information on a generator, a bus, a transmission line, a load, a transformer, a control system in the power system, and information indicating a connection state thereof.

  The reduced system model is a model in which a plurality of coherent generators are grouped together and modeled, and related buses, transmission lines, loads, transformers, and control systems are grouped together. Coherence is a basic concept when determining a system reduction region. The similarity between the active / reactive power of the generator with respect to disturbance and the fluctuation of the internal phase difference angle is called coherence. A sub-system composed of a group of generators having similarities in the active / reactive power of the generator with respect to disturbance and fluctuation of the internal phase difference angle is called a coherence-reducible region.

  The reduced system model storage unit 22 is a storage unit that stores the reduced system model created by the reduced model creation unit 11.

  The reduced parameter tuning unit 12 is a processing unit that adjusts parameters of the reduced system model created by the reduced model creation unit 11. The reduction parameter tuning unit 12 performs reduction based on various data stored in the tidal current section data storage unit 23, the accident case storage unit 24, the setting storage unit 25, the stabilization control amount storage unit 26, and the constraint condition storage unit 27. Adjust the parameters to improve the accuracy of the system model.

  The power flow cross section data storage unit 23 stores the power flow cross section data of the power system input from the input unit 30. The power flow cross section data is information for obtaining a power flow cross section indicating a power flow distribution and a voltage distribution of active power and reactive power at a certain point in the power system. Specifically, the power amount and the load amount per unit time are included. A setting order is set in advance for each tidal current cross-section data. The power flow cross section data storage unit 23 outputs the stored power flow cross section data of the power system to the reduction parameter tuning unit 12.

  The accident case storage unit 24 stores the accident data in the power system input from the input unit 30. The accident data is an accident condition that can be assumed in a target system, and includes an accident point and an accident aspect. For example, the accident point is information such as an accident in the A transmission line, and the accident situation is information such as a 1LC phase ground fault. A setting order is set in advance for each accident data. The accident case storage unit 24 outputs the stored accident data in the power system to the reduced parameter tuning unit 12.

  In the present embodiment, the accident case storage unit 24 stores, for example, an accident case that becomes unstable without the stabilization control. An unstable accident is an accident case in which the system input causes a loss of balance between the mechanical input and the electrical output of the generator, resulting in a step-out phenomenon in which synchronous operation cannot be maintained and an unstable operation state occurs. When the occurrence of the step-out phenomenon is assumed, it is possible to prevent the step-out phenomenon by shutting down the generator which is assumed to be accelerated mainly and difficult to maintain the synchronization. Shutting off the generator is called "power limitation". In the following, “power supply restriction” is collectively referred to as electric control.

  The setting storage unit 25 stores various types of information created by the reduced parameter tuning unit 12 and required for the processing of the reduced model creation device 1. The information stored in the setting storage unit 25 includes an arithmetic expression, a parameter, a reference value (including a threshold value), and the like for processing of each unit. The information stored in the setting storage unit 25 is output to the contracted parameter tuning unit 12 again.

The stabilization control amount storage unit 26 stores the original system stabilization control amount, the reference control amount, and the checker control amount created by the reduction parameter tuning unit 12.
The original system stabilization control amount is a minimum necessary amount of electric control required for the original system model to maintain stability, and includes a power flow section data storage unit 23 and a power flow section set by the accident case storage unit 24. Prepared for each combination of accident cases. The necessary minimum control amount indicates a control amount that does not maintain synchronization and causes a step-out phenomenon when the control amount is smaller than that (when the number of generators to be cut off is reduced).

The reference control amount is a control amount equal to or larger than the original system stabilization control amount, and is set when calculating the oscillation waveform of the original system model and the reduced system model.
The checker control amount is the control amount that is less than the original system stabilization control amount, and is used to determine whether the reduced system model becomes unstable with the control amount that is less than the original system stabilization control amount. Used.

  The constraint condition storage unit 27 stores the constraint condition input from the input unit 30. The constraint condition is a condition for estimating the contraction parameter, and for example, a condition in which the peak value of the fluctuation waveform does not become smaller than that of the original system, or the like. The constraint condition storage unit 27 outputs the stored constraint condition to the contraction parameter tuning unit 12.

(2) Configuration of Reduced Parameter Tuning Unit 12 The reduced parameter tuning unit 12 includes a tide cross section data setting unit 121, an assumed accident case setting unit 122, an original system fluctuation calculation unit 123, a reduced system fluctuation calculation unit 124, and a difference calculation. It has a unit 125, a reduced parameter estimation unit 126, and a reduced parameter output unit 127.

  The tidal section data setting unit 121, based on the tidal section data stored in the tidal section data storage unit 23, according to a preset order, stores the original system model and the reduced system model stored in the original system model storage unit 21. The tidal current section data is set in the reduced system model stored in the storage unit 22. The tidal section data setting unit 121 outputs the original system model and the reduced system model in which the tidal section data is set to the assumed accident case setting unit 122.

  The assumed accident case setting unit 122 is based on the accident data stored in the accident case storage unit 24, and in accordance with a preset order, the original system model in which the tidal current profile data is set by the tidal current profile data setting unit 121 and the contracted model. Set an unstable assumed accident case assumed in the system model. The assumed accident case setting unit 122 outputs the original system model and the reduced system model in which the assumed accident case is set to the original system fluctuation calculation unit 123 and the reduced system fluctuation calculation unit 124.

  The original system fluctuation calculation unit 123 calculates a system fluctuation waveform of the original system model. This calculation is performed on the original system model in which the assumed accident case is set by the assumed accident case setting unit 122, based on the reference electric control amount stored in the stabilization control amount storage unit 26. The system oscillation waveform calculated here is the original system oscillation waveform when the stabilization control is performed with the reference control amount equal to or larger than the original system stabilization control amount stored in the constraint condition storage unit 27. As the system fluctuation waveform, for example, the internal phase angle waveform of the generator of the non-reduced system with respect to the phase reference point, the speed deviation fluctuation waveform of the generator of the non-reduced system, and the validity of the branch of the non-reduced system There are power fluctuation waveforms, power flow waveforms of interconnection lines between the contracted system and the non-reduced system, and the like. The original system fluctuation calculator 123 outputs the system fluctuation waveform of the original system model to the difference calculator 125.

  The reduced system fluctuation calculator 124 calculates a system fluctuation waveform of the reduced system model. This calculation is performed on the reduced system model in which the assumed accident case is set by the assumed accident case setting unit 122, based on the reference control amount stored in the stabilization control amount storage unit 26. When the stabilization control is performed with the reference control amount equal to or larger than the original system stabilization control amount, the system fluctuation waveform of the reduced system model is calculated. The reduced system fluctuation calculator 124 outputs the system fluctuation waveform of the reduced system model to the difference calculator 125.

  The difference calculator 125 calculates a difference between the system fluctuation waveform of the original system model calculated by the original system fluctuation calculator 123 and the system fluctuation waveform of the reduced system model calculated by the reduced system fluctuation calculator 124. . The difference calculation unit 125 outputs an error between the system fluctuation waveform of the original system model and the system fluctuation waveform of the contracted system model to the contracted parameter estimation unit 126.

  The difference calculation unit 125 includes a system fluctuation difference calculation unit 125a and a difference output unit 125b, as shown in FIG. An error between the system fluctuation waveform of the original system model and the system fluctuation waveform of the reduced system model is calculated by the system fluctuation difference calculation unit 125a. As a method of calculating the error of the system fluctuation waveform, a Euclidean distance, a correlation coefficient, a peak value error up to the Nth wave of the waveform, and the like are used. Further, the time domain for calculating the waveform error may be any of the methods for calculating the waveform error only in a time zone from the time of the occurrence of the accident until the system convergence converges, in addition to the entire time domain. The difference output unit 125b outputs the error of the system oscillation calculated by the system oscillation difference calculating unit 125a.

  The reduced parameter estimating unit 126 estimates and calculates a reduced parameter so as to minimize an error between the system fluctuation waveform of the original system model and the system fluctuation waveform of the reduced system model output from the difference calculation unit 125. The contracted parameter estimating unit 126 outputs the calculated parameters of the contracted system model to the contracted parameter output unit 127.

  As shown in FIG. 3, the reduced parameter estimating unit 126 includes a difference determining unit 126a, a constraint condition setting unit 126b, and a reduced parameter adjusting unit 126c.

  The difference determination unit 126a determines a match between the system fluctuations of the original system model and the reduced system model based on the system fluctuation error and the threshold. The constraint condition setting unit 126b sets the constraint condition stored in the constraint condition storage unit 27. When the difference determination unit 126a determines that the system fluctuation of the reduced system model does not match the system fluctuation of the original system model, the reduced parameter adjustment unit 126c adjusts the reduced parameters.

  The contraction parameter adjustment unit 126c adjusts the contraction parameter such that an error between the system fluctuation waveform of the reduced system model and the system fluctuation waveform of the original system model is minimized. The reduced parameters include network parameters that determine the reduced system network, such as the output of the reduced generator, reduced load, and reduced system impedance, and reduced generators such as the PSS and AVR parameters of the reduced generator. And the inertia constant. Since there are restrictions on short-circuit capacity, power flow distribution, system capacity, and the like, it is necessary to optimize a plurality of continuous value parameters, and a constrained nonlinear optimization method is desirable as a means for adjusting the reduction parameters.

  The reduced parameter output unit 127 outputs the reduced parameters of the reduced system model estimated by the reduced parameter estimation unit 126.

[1-2. Action]
Next, an outline of the operation of the power system contracted model creation device of the present embodiment will be described. FIG. 4 is a flow chart of a computer program for creating a power system reduced model built in the power system reduced model creation device 1. The power system contracted model creation device 1 performs operation and calculation in the following procedure.

(Step S10: Tidal current cross section data setting)
First, the tidal section data setting unit 121, based on the tidal section data stored in the tidal section data storage unit 23, according to a preset order, stores the original system model and the reduced model stored in the original system model storage unit 21. The tidal current section data is set in the reduced system model stored in the approximately system model storage unit 22.

(Step S11: assumed accident case setting)
Next, based on the accident data stored in the accident case storage unit 24, the assumed accident case setting unit 122, in accordance with the preset order, sets the original system model and the reduced system in which the tidal current cross-section data is set in step S10. In the model, set an assumed unstable assumed accident case.

(Step S12: Calculation of original system model system fluctuation)
Next, the original system fluctuation calculation unit 123 calculates a system fluctuation waveform of the original system model. Specifically, using the original system model stored in the original system model storage unit 21, the reference system stored in the stabilization control amount storage unit 26 is used for the original system model in which the assumed accident case is set in step S <b> 11. The system fluctuation waveform of the original system model when the stabilization control is performed with the control is calculated. The system fluctuation waveform is calculated from the transient stability calculation (system simulation) result.

(Step S13: optimization preparation processing)
Next, the reduced system fluctuation calculator 124 calculates a system fluctuation waveform of the reduced system model. Step S13 is a step of executing an optimization preparation process in a stage before optimizing the reduction parameter. Specifically, based on the reference control amount stored in the stabilization control amount storage unit 26, calculation is performed on the reduced system model in which the assumed accident case is set by the assumed accident case setting unit 122. When the stabilization control is performed with the reference control amount equal to or larger than the original system stabilization control amount, the reduced system fluctuation calculation unit 124 calculates the system fluctuation waveform of the initial value of the reduced system model.

  The difference calculator 125 calculates a difference between the system fluctuation waveform of the original system model calculated by the original system fluctuation calculator 123 and the system fluctuation waveform of the reduced system model calculated by the reduced system fluctuation calculator 124. . The difference calculation unit 125 calculates a system fluctuation waveform of the original system model and a system fluctuation waveform of the reduced system model as objective functions.

  Step S13 includes steps S131 to S133 shown in FIG. The present embodiment shows, as an example, optimization using a differential evolution method (DE), which is one of the optimization techniques. As the optimization method, another method such as a genetic algorithm can be applied, and is not limited to DE. Hereinafter, the processing in step S13 will be described.

(Step S131: Data reading process)
The reduced system fluctuation calculation unit 124 reads data necessary for the optimization preparation processing from the accident case storage unit 24, the setting storage unit 25, the stabilization control amount storage unit 26, and the constraint condition storage unit 27. More specifically, the base system of the reduced system from the reduced system model storage unit 22, the target accident sequence from the accident case storage unit 24, the base system data of the reduced system from the setting storage unit 25, the original system , The upper and lower limit values of the optimization parameters from the stabilization control amount storage unit 26, and the respective constraint conditions (penetration impedance from the reduction point, interconnection line flow, interconnection point voltage, The sum of the rated generator capacity and the rated output of the system to be reduced, the total load demand of the system to be reduced, etc.) are read.

(Step S132: Random Generation of Reduction Parameters)
The reduction parameters to be optimized are randomly set between the upper and lower limits of the optimization parameters read in step S131. As an example, FIG. 6 shows the configuration of the reduced system in the present embodiment. FIG. 7 shows optimization parameters of the two-machine, two-load reduced system corresponding to the two-machine, two-load reduced model shown in FIG.

The generator output distribution ratio in the two-machine two-load reduced system is shown as the output of RG1 with respect to the total output of the two reduced generators. Note that PG total which is the total output of the two contracted generators is calculated by equation (1). The rated capacity, rated output, and active power output of the two reduced generators are determined from the PG total and the total generator rated capacity and rated output of the system to be reduced, which is a constraint, and the generator output distribution ratio. You.
PGtotal = PLtotal-Ptie Equation (1)
PLtotal: Total load demand of the contracted system
Ptie ・ ・ ・ Connection line current

  The load distribution ratio indicates the active power of PL1 with respect to the total active power of the two loads in the reduced system. The active power of each of the two loads of the contracted system is determined from the total load demand of the contracted system and the load distribution ratio, which are the constraint conditions.

  FIG. 8 shows a control block and optimization parameters of the reduced generator AVR, and FIG. 9 shows a control block and optimization parameters of the PSS. In the present embodiment, the AVR is a thyristor type super-speed excitation, and the PSS is a ΔP type PSS.

(Step S133: Objective function calculation)
An objective function is calculated for the reduced parameters determined in step S132. Details will be described later. The process of step S133 is repeated N times, which is the designated number of solutions.

(Step S14: Reduction parameter optimization processing)
Next, the reduced parameter estimating unit 126 estimates the reduced parameter so as to minimize the error between the system fluctuation waveform of the original system model and the system fluctuation waveform of the reduced system model, which has been processed in step S13. The reduced parameter estimating unit 126 performs optimization processing of the reduced parameters of the estimated reduced system model. Step S14 includes steps S141 to S144 shown in FIG. Steps S141 to S144 are processing of reduced system optimization utilizing a differential evolution method, which is one of metaheuristics. DE is a heuristic meta-heuristic similar to a genetic algorithm (GA). However, S141 to S144 omit processes required for GA such as binarization by targeting only continuous values, and reduce computation speed and speed. The algorithm has improved convergence.

(Step S141: Create mutation vector Vi for X _{i, G} (individual i of generation G))
The contracted parameter estimating unit 126 creates a mutation vector Vi for X _{i, G} (individual i of generation G) according to equation (2). Three individuals are randomly extracted from the solution of the current generation, and a new mutation vector is generated for X _{i, G} by equation (2).
Vi = X _rl + F × (X _r2 −X _r3 ) Equation (2)
F: Real number of 0 to 1 (scaling parameter)
_Xr1 , _Xr2 , _Xr3 : Individuals randomly extracted from X1 _{, G} to _{Xn, G}

(Step S142: Intersect with Xi _{, G} and Vi to create test vector Ui)
Next, as shown in FIG. 11, the contraction parameter estimating unit 126 creates a test vector Ui by intersecting the mutation vector Vi created in step S141 with Xi, G. As the intersection method, a method such as one point intersection, another point intersection, uniform intersection, or the like is applied. FIG. 11 shows an example of a one-point intersection as an example. The intersection position is determined at random, and the intersection is made before or after the intersection position (FIG. 11 shows a rear intersection). After the intersection, two vectors Ui1 and Ui2 are generated, and one final test vector is randomly selected from Ui1 and Ui2. In the present embodiment, it is assumed that Ui1 is selected.

(Step S143: Calculate objective function of Ui)
Next, the contracted parameter estimating unit 126 calculates an objective function in the same manner as in step S133. The objective function calculation processing will be described later.

(Step S144: Ui and Xi _{, G} , which has a better objective function value, are defined as Xi _{, G + 1} ).
Next, the contracted parameter estimating unit 126 compares the test vector Ui generated in step S142 with the objective function value of the solution Xi _{, G} of the current generation, and determines the one with the better objective function value as the solution Xi _{, G + 1} .

  The processing of steps S141 to S144 is repeated for the number of designated solutions N × the maximum number of designated generations G times to calculate the final optimal solution. Instead of performing the calculation for the maximum number of specified generations G, set a threshold for the objective function or a threshold for the rate of change of the objective function, and terminate the calculation when the objective function or the rate of change of the objective function falls below the threshold. You may make it.

(Step S15: Reduction parameter output)
Next, the reduced parameter output unit 127 outputs the reduced parameters of the reduced system model calculated by the reduced parameter estimation unit 126.

(Objective function calculation processing)
Next, details of the processing for calculating the objective function in steps S133 and S144 will be described. Steps S133 and S144 include steps S1331 to S1336 shown in FIG.

(Step S1331: System section set)
The contracted parameter estimating unit 126 updates information such as the contracted generator output and the capacity, the contracted load and the contracted impedance for each target system section. Information such as the reduced generator output and capacity, the reduced load and the reduced impedance can be obtained from an information transmission device external to the power system reduced model creation device 1 via communication or the Internet.

(A, Update of reduced system model)
(A-1) Update of Reduced Load / Reduced Generator Output, Reduced Generator Rated Capacity / Reduced Generator Rated Output The reduced parameter estimation unit 126 calculates the reduced load (P) / reduced generator output. (P) The contracted generator rated capacity and the contracted generator rated output are updated in the following procedure. Here, (P) indicates the active power. (P, Q) indicates both active power and reactive power.

(1) Calculate total contracted generator output from total external system demand and interconnection flow. Total contracted generator output (P) = external system total demand (P)-interconnection line flow (P).
(2) For each reduced load (P), the external system total demand (P) is apportioned according to the load distribution ratio, and the optimization parameters are calculated.
(3) Reduced generator output (P) / reduced generator rated capacity / reduced generator rated output is total reduced generator output (P) / external system generator total rated capacity / system generator total rating The output is apportioned by the generator distribution ratio, and the optimization parameters are calculated.

(A-2) Update of reduced system branch reactance Interconnection line power flow (P, Q), interconnection point voltage / phase, non-reduction target system from interconnection point (own system), reduction system (external system) X) and X2 are calculated using the peeping short-circuit impedance of (2) as an input.

(B, update of own system)
Information in the own system can be obtained online via an intranet or the like. The contraction parameter estimating unit 126 updates the values of each generator output (PV), rated output, rated capacity, and each load (P, Q) in the own system.

(Step S1332: accident case set)
The contraction parameter estimating unit 126 sets a system fault case as a reference based on the fault data in the power system stored in the fault case storage unit 24. The system accident cases include, for example, an equilibrium accident such as a two-line six-phase ground fault (6LG-O) or a one-line three-phase ground fault (3LG-O), and an imbalance accident such as a one-line two-phase ground fault. . Further, the contraction parameter estimating unit 126 also determines a control amount to be used as a reference.

(Step S1333: Electricity control set)
The reduction parameter estimating unit 126 calculates a minimum original system stabilization control amount (T) required for stabilizing the original system model for each combination of the system section set in step S1331 and the system fault set in S1332. ), A reference control amount (α) used as a reference when adjusting the oscillation waveform, and a checker control amount (β) smaller than the original system stabilization control amount set by the control amount constraint in step S1336 described later. ) Is set.

  FIG. 14 shows the relationship between the minimum control amount (T) of the original system, the reference control amount (α), and the checker control amount (β). Here, the checker control amount (β) is a control amount obtained by subtracting the minimum controllable amount that can be reduced from the minimum original system stabilization control amount (T). Specifically, for example, the control amount is a control amount obtained by subtracting the generator output of the minimum output from among the outputs of the electric control target machines included in the electric control amount T.

  By setting the control amount as described above, if the reduced system model becomes unstable due to the checker control amount (β), it becomes possible to prevent the system from becoming insufficiently controlled compared to the original system model. . As the reference control amount (α), a control amount equal to or more than the minimum original system stabilization control amount (T) is set. By setting the reference control amount (α) to a value close to the minimum original system stabilization control amount (T), the required power control amount of the reduced system model is matched with the original system model.

  It is important to set a stable reference control amount (α) close to the minimum stabilization control amount (T) of the original system that can be stabilized. The system cross section set in step S1331 and the original system stabilization control amount (T), reference control amount (α), and checker control amount (β) set for each combination of the system fault set in step S1332. An example is shown in FIG.

(Step S1334: Motion waveform error calculation)
When the system fault set in step S1332 occurs in the system section set in step S1331, the reduction parameter estimating unit 126 performs power control with the reference control amount (α) set in step S1333. The error between the system fluctuation waveform of the original system model and the system fluctuation waveform of the reduced system model is calculated according to equation (3).

AG r(i,t)：縮約系統モデルにおける時刻tの発電機iの位相基準からの内部相差角
AG(i,t)：原系統モデルにおける時刻tの発電機iの位相基準からの内部相差角
i：発電機の番号 t：時間
なお動揺波形は、位相基準からの発電機Ｇ１〜Ｇ１０（非縮約対象系統）の内部相差角としたが、これに限定されない。以降目的関数の計算に使用される「位相基準からの非縮約系統内の発電機内部相差角波形」を、「対象動揺波形」と総称する。 Error summation of the internal phase difference angle of the generator of the non-reduced system from the phase reference

AG r (i, t): Internal phase difference angle from the phase reference of generator i at time t in the reduced system model
AG (i, t): internal phase difference angle from the phase reference of generator i at time t in the original system model
i: Generator number t: Time
The oscillation waveform is the internal phase difference angle of the generators G1 to G10 (non-reduction target system) from the phase reference, but is not limited to this. Hereinafter, the “phase difference angle waveform inside the generator in the non-reduced system from the phase reference” used in the calculation of the objective function is collectively referred to as “target oscillation waveform”.

(Step S1335: Waveform peak value constraint)
The contracted parameter estimating unit 126 uses the voltage phase of the interconnection point as a reference in order to prevent the reduced system model from having more stability (optimism) than the original system model. When the reduced system model is lower than the original system model with respect to the peak value of the internal phase difference angle of the generator, a penalty value is added to the target oscillation waveform error of the above equation (3) as the waveform value peak constraint.

(Step S1336: Electricity control restriction)
The reduction parameter estimating unit 126 performs the above-described operation when the reduced system model is not unstable when the power reduction is performed with the checker power reduction (β) less than the original system stabilization control amount set in step S1333. A penalty value is added to the target fluctuation waveform error of Expression (3). This penalty value excludes that the reduced system model has more stability (optimism) than the original system model.

  The fluctuation waveform error including the penalty value calculated in steps S1331 to S1336 is added to the loop of each cross section and the loop of each accident as an objective function. The objective function is minimized by the optimization processing of FIG. 10 to reduce the power control error in all target sections and all accidents, and bring the dynamic characteristics of the reduced system closer to the original system model.

[1-3. effect]
(1) According to the present embodiment, since the objective function calculation processing module shown in FIG. 12 is provided, it is possible to simultaneously minimize the sway error of a plurality of cross sections and a plurality of accidents. It is possible to construct a high-accuracy reduced system model without switching the reduced system model for multiple cross sections and multiple accidents.

(2) According to the present embodiment, since the checker control amount (β) is applied to the control amount restriction, the reduced system model has more stability than the original system model (becomes optimistic). ) It is possible to avoid creating a reduced system model.

(3) According to the present embodiment, the reduced parameter estimating unit 127 creates a plurality of reduced system models for the plurality of tidal current cross-section data set by the tidal current cross-sectional data setting unit 121, and generates a plurality of tidal current cross-sectional models. For a combination of a plurality of unstable accident cases set by the assumed accident case setting unit 122 corresponding to the data, the sum of the differences between the oscillation waveform of the original system model and the oscillation waveform of the reduced system model is minimized. Therefore, it is possible to create a reduction model of a power system having a high-precision reduction parameter.

(4) According to the present embodiment, the stabilization control amount storage unit 26 stores the original system stabilization control amount and the original system stabilization for each combination of the plurality of tide flow data and the plurality of unstable accident cases. The reference control amount equal to or larger than the control amount and the checker control amount equal to or smaller than the original system stabilization control amount are stored. The reduction parameter estimating unit 127 compares the reference control amount stored in the stabilization control amount storage unit 26 with the reference control amount. The checker control is used to confirm that the oscillation waveforms of the original system model and the reduced system model do not become unstable, and the reduction parameters are calculated. Simulation can be performed using the stabilization control amount, reference control amount, and checker control amount, and it is possible to create a reduced model of the power system having highly accurate reduction parameters. .

(5) According to the present embodiment, the checker control amount is a control amount obtained by subtracting the minimum control amount that can be reduced from the original system stabilization control amount. A reduced model of the power system based on the operation can be created.

[2. Second Embodiment]
[2-1. Constitution]
An example of the power system contracted model creation device according to the second embodiment will be described with reference to FIG. In the second embodiment, a control amount adjustment process S1337 is added to the objective function calculation process of the first embodiment shown in FIG. The objective function calculation process according to the second embodiment is different from the first embodiment in that the objective function calculation process includes a control amount adjustment process S1337. The configuration of the power system contracted model creation device of the second embodiment is the same as that of the first embodiment shown in FIG.

[2-2. Action]
Next, an outline of the operation of the power system contracted model creation device of the present embodiment will be described with reference to FIGS.

  The control amount adjustment process S1337 is a processing unit for searching for a stable control amount α close to the original system stabilization control amount T, and reducing a control amount error of a plurality of cross sections and a plurality of accidents. FIG. 17 shows an operation flow of the power control amount adjustment processing S1337.

(Step S1337-1: Unstable generation count up)
When it is determined that the stability calculation result of the reduced system model becomes unstable with the current reference control amount α, the reduced parameter estimation unit 126 counts up the unstable generation number counter by the following equation. I do.
Count (i, d, f) = Count (i, d, f) +1 Expression (4)
i: Individual number
d: System section number
f: Accident case number

(Step S1337-2: α increase)
When it is determined that the number of unstable generations exceeds the allowable number of unstable generations as in Expression (5), the contraction parameter estimation unit 126 can increase the current reference control amount α according to Expression (6). It is increased by the minimum control amount Δα. The minimum control amount Δα corresponds to, for example, the generator output of the minimum output among the power generation target generators not included in the reference control amount α. Also, the initial value of α is set to T.
Count (i, d, f)> Gen th ・ ・ ・ Equation (5)
α (i, d, f) = α (i, d, f) + Δα (6)
α (i, d, f): individual i, cross section d: reference charge for accident case f
Count (i, d, f): Generation counter that became unstable at α (i, d, f)
Gen th: Allowable unstable generation number

(Step S1337-3: Unstable Generation Number Count Initialization)
When the reference control amount α is increased in step S1337-2, the contraction parameter estimation unit 126 resets Count (i, d, f) to 0.

[2-3. effect]
(1) According to the present embodiment, since the control amount adjustment processing S1337 shown in FIG. 16 is provided and the reference control amount α is gradually increased for the cross section / accident case where the unstable case continues, the total cross section / accident It is possible to set a stable and necessary minimum reference control amount α for the case. As a result, it is possible to reduce the power control error.

(2) According to the present embodiment, the reference control amount is obtained by setting the original system stabilization control amount as an initial value, and shaking the reduced system model for each combination of a plurality of tidal current cross-sectional data and a plurality of unstable accident cases. Until the waveform becomes a reduction parameter that becomes stable, the control amount is increased and calculated in increments of a preset amount. Therefore, by reducing the increment of the preset amount, reduction with higher accuracy can be achieved. A reduced model of a power system having parameters can be created.

[Other embodiments]
Although the embodiments including the modified examples have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in other various forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the invention described in the claims and their equivalents. The following is an example.

(1) In the above embodiment, the present invention is realized by a computer including a CPU controlled by a predetermined program or module. By the above-mentioned programs or modules, hardware is physically utilized, and processing of each unit is realized. The configuration of the power system contraction model creation device 1 according to the above embodiment is an exemplification, and the function of the hardware configuring the system is not limited to the above embodiment.

(2) In the above embodiment, the power system contraction model creation device 1 has been described. However, an apparatus, a method, a program or a module for executing each process in the above embodiment, and a recording medium on which the program is recorded are also included in the embodiment. It is an aspect. The range of processing by hardware and the range of processing by software including a program are not limited to the above embodiment. Each process in the above embodiment may be configured by hardware.

(3) In the above embodiment, the original system model storage unit 21, the reduced system model storage unit 22, the tidal section data storage unit 23, the accident case storage unit 24, the setting storage unit 25, the stabilization control amount storage unit 26, the constraint Each storage unit of the condition storage unit 27 is provided inside the power system reduced model creation device, but may be arranged outside the power system reduced model creation device.

(4) In the above embodiment, the input unit 30 and the output unit 40 are provided inside the power system reduced model creation device, but are arranged outside the power system reduced model creation device. Is also good.

(5) In the above embodiment, the reduced model of the two-machine and two-load configuration shown in FIG. 6 is connected at one point, but the connection mode is not limited to this. The contracted model may be a two-point interconnection and a multi-point interconnection by establishing a constraint formula for the short-circuit capacity and the interconnection flow.

(6) In the above embodiment, in the system sectional set in step S1331, the peep short-circuit impedance is acquired by communication. However, if the peep short-circuit impedance cannot be acquired by communication, the value before update is used. It may be.

(7) In the above embodiment, the method of moderately adjusting the reference control amount α is applied to the cross section and the accident case in which the generation in which the stability calculation result becomes unstable is applied. Not limited to A method may be used in which the reference electric control amount α for each cross section and accident case is solved by an optimization method as one of the reduction parameters. In this case, since it is necessary to set the reference control amount α corresponding to the number of the target cross section × accidents, when the number of the target cross section × accidents is large, the reduction parameter increases, and the convergence of the solution is increased. Care needs to be taken.

1 Reduced Model Creation Device 11 Reduced Model Creation Unit 12 Reduced Parameter Tuning Unit 21 Original System Model Storage Unit 22 Reduced System Model Storage Unit 23 Power flow section data storage unit 24 Accident case storage unit 25 Setting storage unit 26 Stabilized control amount storage unit 27 Constraint condition storage unit 30 Input unit 40 Output unit 121 ... tidal current cross section data setting unit 122 ... assumed accident case setting unit 123 ... original system fluctuation calculation unit 124 ... reduced system fluctuation calculation unit 125 ... difference calculation unit 126 ... reduction Parameter estimation unit
127 ... reduced parameter output unit

Claims (6)

A reduced model creation unit that creates a reduced system model from the original system model of the power system;
A reduced parameter tuning unit for adjusting a reduced parameter of the reduced system model, and a power system reduced model creation device comprising:
The reduced parameter tuning unit includes:
A tidal section data setting section for setting arbitrary tidal section data;
Assumed accident case setting unit that sets an unstable accident case corresponding to the tidal current data set by the tidal current data setting unit,
In the unstable accident case set by the assumed accident case setting unit, a stabilization control amount storage unit that stores an original system stabilization control amount that is a minimum control amount required for stabilization of the original system model. When,
In the unstable accident case, an oscillation waveform of the original system model when the stabilization control is performed with the reference control amount that is equal to or more than the original system stabilization control amount stored in the stabilization control amount storage unit is calculated. A system fluctuation calculator,
In the unstable accident case, calculate the fluctuation waveform of the reduced system model when the stabilization control is performed with the reference control amount that is equal to or more than the original system stabilization control amount stored in the stabilization control amount storage unit. A reduced system sway calculation unit,
A difference calculation unit that calculates a difference between the oscillation waveform of the original system model calculated by the original system oscillation calculation unit and the oscillation waveform of the reduced system model calculated by the reduced system oscillation calculation unit.
A contraction parameter estimator that estimates the contraction parameter so as to minimize the difference calculated by the difference calculator;
Has,
The reduced parameter estimating unit creates a plurality of the reduced system models for the plurality of tidal current data set by the tidal current data setting unit, and corresponds to the assumed accident corresponding to the plurality of the tidal current data. For the combination of the plurality of unstable accident cases set by the case setting unit, the reduced parameter in which the sum of differences between the fluctuation waveform of the original system model and the fluctuation waveform of the reduced system model is minimized. A power system contraction model creation device that calculates The stabilization control amount storage unit includes, for each combination of a plurality of the tidal current cross-sectional data and a plurality of the unstable accident cases, the original system stabilization control amount and a reference control amount equal to or more than the original system stabilization control amount. And storing a checker control amount less than the original system stabilization control amount,
The reduced parameter estimating unit calculates the oscillation waveform of the original system model and the oscillation waveform of the reduced system model using the reference control amount and the checker control amount stored in the stabilization control amount storage unit. Confirm that it does not become unstable, calculate the contraction parameter,
The power system contracted model creation device according to claim 1.   The power system contraction model creation device according to claim 2, wherein the checker power control amount is a control amount obtained by subtracting a minimum control amount that can be reduced from the original system stabilization control amount.   The reference power control amount, with the original system stabilization control amount as an initial value, for each combination of the plurality of tidal current data and the plurality of unstable accident cases, the fluctuation waveform of the reduced system model becomes stable. The power system contraction model creation device according to claim 2 or 3, wherein the control amount is increased and calculated in increments of a preset amount until the reduction parameter is reached.   The reduced parameter estimating unit calculates the reference control amount, which is a reduced parameter that makes the oscillation waveform of the reduced system model stable for each combination of the plurality of tidal current cross-sectional data and the plurality of unstable accident cases. The power system contraction model creation device according to claim 2 or 3, wherein an optimization method is applied to the power system. A reduced model creation means for creating a reduced system model from the original system model of the power system;
A reduced parameter tuning means for adjusting a reduced parameter of the reduced system model, and a power system reduced model creating method comprising:
The reduced parameter tuning means includes:
A tidal section data setting means for setting arbitrary tidal section data;
Assumed accident case setting means for setting an unstable accident case corresponding to the tidal current data set by the tidal current data setting means,
In the unstable accident case set by the assumed accident case setting means, a stabilized control amount storage means for storing an original system stabilization control amount which is a minimum control amount required for stabilizing the original system model. When,
In the unstable accident case, an oscillation waveform of the original system model is calculated when the stabilization control is performed with the reference control amount that is equal to or more than the original system stabilization control amount stored in the stabilization control amount storage unit. System fluctuation calculation means,
Calculate the fluctuation waveform of the reduced system model when performing the stabilization control with the reference control amount that is equal to or more than the original system stabilization control amount stored in the stabilization control amount storage means in the unstable accident case. A reduced system fluctuation calculation means,
Difference calculation means for calculating a difference between the oscillation waveform of the original system model calculated by the original system oscillation calculation means and the oscillation waveform of the reduced system model calculated by the reduced system oscillation calculation means,
Reduction parameter estimation means for estimating the reduction parameter so as to minimize the difference calculated by the difference calculation means,
Has,
The reduced parameter estimating means creates a plurality of the reduced system models for the plurality of tidal current data set by the tidal current data setting means, and corresponds to the assumed accident corresponding to the plurality of the tidal current data. The reduced parameter for which the sum of the differences between the fluctuation waveform of the original system model and the fluctuation waveform of the reduced system model is minimized for a combination of the plurality of unstable accident cases set by the case setting means. Calculate the power system reduced model creation method.

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