JP2022187382A - Power demand-supply plan creation device and method - Google Patents

Abstract

To propose a power demand-supply plan creation device and method capable of creating a demand-supply plan in which a calculation time is practical, while securing safety of a power system.SOLUTION: Stability of a power system with respect to each credible accident on a time basis is evaluated. Regarding each unstable case consisting of a time evaluated to be unstable and the credible accident, a stabilization measure for stabilizing the power system is created. The created stabilization measure for each unstable case is respectively approximated into a stabilization operation restriction expression, and a demand-supply plan is created so as to satisfy all the approximated stabilization operation restriction expressions for each of the unstable cases.SELECTED DRAWING: Figure 3

Description

The present invention relates to an electric power supply and demand planning apparatus and method, and is particularly suitable for application to an electric power supply and demand planning apparatus for preparing an electric power supply and demand plan.

Conventionally, power supply and demand planning is based on the power demand forecast value at each time of the planning period, so that each generator and the operational constraints of the power system are satisfied. It is made to determine the output of the stop and generator. For example, Non-Patent Literatures 1 and 2 disclose methods for creating such supply and demand plans.

As disclosed in Non-Patent Documents 1 and 2, such a supply and demand plan has a supply and demand balance in which the demand and supply of electric power match, and a minimum continuous state in which the state of the generator is maintained for a certain period of time during startup and after shutdown. It is calculated so as to minimize the total power generation cost while satisfying the operational constraints of each generator and power system, such as start-up time and minimum stop time.

In this case, even if there is only one generator, for example, in order to consider the two states of starting and stopping the generator for all of the number of time slices (assumed to be n) in the supply and demand plan, 2 A huge number of ⁿ combinations of supply and demand plans are conceivable. Therefore, when calculating such a demand-supply plan, an optimization method that can quickly determine a demand-supply plan that minimizes the total power generation cost from among a huge number of demand-supply plans is essential.

On the other hand, in recent years, large-scale power generation facilities that generate renewable energy, such as photovoltaic power generation, whose output depends on the weather, have been connected to power systems. In this case, as the amount of power generated by renewable energy increases, the output of existing power sources such as thermal power generators and the number of units to be activated will decrease. Since the existing power sources are subject to adjustment, the fewer the number of existing power sources, the more difficult it becomes to stabilize the power system (system stabilization).

Regarding system stabilization, transient stability that maintains the stability of the power system even after a disturbance such as a ground fault in the transmission line, system frequency fluctuations due to demand and renewable energy output fluctuations, and system voltage fluctuations. and maintenance within the voltage control range are conceivable.

If the supply and demand plan is created without considering the stability of the power system, it is possible that the above-mentioned system stability will not be ensured and operation will not be possible. System stability should be considered.

There is Non-Patent Document 3 as a document that considers system stability, but the technology disclosed in this Non-Patent Document 3 is aimed at adjusting the output of a generator only at a specific time, and is similar to a supply and demand plan. No consideration is given to the starting state (starting or stopping) of the generator at multiple points in time within a specific period and the amount of output power.

In this case, by combining the technology disclosed in Non-Patent Document 1 and Non-Patent Document 2, which are existing supply and demand plans, and the technology disclosed in Non-Patent Document 3, such consideration can be made. However, there is a problem that the scale of matters to be considered becomes enormous and requires a great amount of computation time.

In addition, many nonlinear characteristics such as output saturation are included in generator control devices, but in order to simplify the power system and consider it in these documents, the transient characteristics of the power system are not considered in detail. However, there is a concern that the accuracy will deteriorate when system stabilization is taken into consideration.

Mototsune Yoshikawa, Toshiyuki Sawa, Hiroshi Nakajima, Mitsuo Kinoshita, Yoshiyuki Kurebayashi, Yuji Nakata: "Methods for Creating Operation Plans for Thermal and Pumped-storage Power Plants", IEEJ, Vol.114, No.12 (1994) Toshiyuki Sawa, Yasuo Sato, Mitsuo Tsurugi, Tsukasa Onishi, "Preparation of integrated next-day operation plan for thermal power, pumped storage, hydraulic power and interchange considering tidal current constraints", IEEJ Trans.PE, Vol.128, No.10 (2008) Yan Xu, et al., ``Power system Transient Stability-Constrained Optimal Power Flow: A Comprehensive Revie'', IEEE Power and Energy Society General Meeting, July, 2012 Kuniaki Anzai, Kimihiko Shimomura, Soshi Yoshiyama, Hiroyuki Tanaka, Masaru Takeishi, Takashi Sasaki: "Development of an online integrated system stabilization system (ISC) applied to long-distance high-power transmission systems", Transactions of the Institute of Electrical Engineers of Japan B( Power and Energy Division), VOl133, No.4 pp.313-323 (2013) Alejandro Pizano-Martinez, et al., ``Global Transient Stability-Constrained Optimal Power Flow Using an OMIB Rererence Trajectory'', IEEE TRANSACTIONS ON POWER SYSTEMS, VOL.25, NO.1, FEBRUARY, (2010)

As described above, with the increase in renewable energy connected to the electric power system, it is necessary to create a supply and demand plan that can ensure the stability of the electric power system and realize stable electric power operation, which is becoming more important. On the other hand, when the stability of the electric power system is taken into consideration by the existing method of creating a supply and demand plan, there is a problem that the evaluation accuracy of the stability of the electric power system is low and an enormous amount of calculation time is required which is not practical.

The present invention has been made in consideration of the above points, and proposes an electric power supply and demand plan creating apparatus and method capable of creating a power supply and demand plan with a practical calculation time while ensuring the stability of the electric power system. is.

In order to solve this problem, in the present invention, in a power supply and demand plan creation device for creating a power supply and demand plan in a target power system, system stability for evaluating the stability of the power system for each assumed accident at each time and a system stabilization condition for creating a stabilization measure for stabilizing the power system for each unstable case consisting of a combination of the time and the assumed accident evaluated as unstable by the system stability evaluation unit. An extraction unit, an approximation constraint condition creation unit that approximates the stabilization measures for each unstable case created by the system stabilization condition extraction unit to the stabilization operation constraint equation, and the approximate constraint creation unit and a supply and demand planning unit for creating the supply and demand plan so as to satisfy all of the stabilizing operation constraint expressions for each of the approximated unstable cases.

Further, in the present invention, there is provided a power supply and demand plan creation method executed by a power supply and demand plan creation device for creating a power supply and demand plan in a target power system, wherein the stability of the power system for each assumed accident at each time and a second step of creating a stabilization measure for stabilizing the power system for each unstable case consisting of a combination of the time evaluated as unstable and the assumed accident, creating a third step of approximating the stabilization measures for each of the unstable cases to a stabilization operation constraint expression, and the supply and demand plan so as to satisfy all of the stabilized operation constraint expressions for each of the approximated unstable cases and a fourth step of creating

According to the power supply and demand plan creation apparatus and method of the present invention, it is no longer necessary to consider the characteristics of the power system that require complicated calculations when calculating the power supply and demand plan, and the stability of the power system is ensured in a practical calculation time. Can create supply and demand plans.

ADVANTAGE OF THE INVENTION According to this invention, the power supply-and-demand plan preparation apparatus and method which can create the supply-and-demand plan whose calculation time is practical, can be implement|achieved, after ensuring the stability of an electric power system.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which shows the structural example of the electric power supply-and-demand plan preparation apparatus by 1st Embodiment, and an electric power system. It is a block diagram which shows the relationship between each database and each function part. It is a flow chart which shows a processing procedure of supply and demand plan calculation processing by a 1st embodiment. 9 is a flowchart showing a processing procedure of stabilization constraint expression calculation processing; FIG. 10 is a chart for explaining stabilization operation constraint information; FIG. It is a figure which shows a specific example of the operation|movement constraint condition of a demand-and-supply plan. It is a block diagram which shows the structural example of the electric power supply-and-demand plan production apparatus by 2nd Embodiment, and an electric power system. It is a flow chart which shows a processing procedure of supply and demand plan calculation processing by a 2nd embodiment.

One embodiment of the present invention will be described in detail below with reference to the drawings. It should be noted that the embodiments described below are merely examples, and are not intended to limit the invention itself to specific contents.

Also, in the following description, the same or similar elements and processes are denoted by the same reference numerals, and redundant description is omitted. Further, in the embodiments described later, only differences from the previously described embodiments will be described, and redundant description will be omitted.

In addition, the following description of the embodiments and the configurations and processes shown in the respective drawings show the outlines of the embodiments to the extent necessary for understanding and implementing the present invention, and limit the modes of implementation according to the present invention. It is not intended to be Further, the forms of each embodiment and each modification can be combined in whole or in part without departing from the gist of the present invention and within a mutually compatible range.

(1) First Embodiment (1-1) Configuration of Electricity Demand and Supply Planning Apparatus According to the Present Embodiment In FIG. 1, 1 indicates an electric power supply and demand planning apparatus according to the present embodiment as a whole. This power supply and demand plan creation device 1 is a device having a function of creating a power supply and demand plan in the power system 2 based on various information about the power system 2 given in advance and various measurement information acquired from the power system 2 . be.

The power system 2 is a system in which a plurality of generators 10 and loads 11 are interconnected via busbars (nodes) 12, transformers 13, transmission lines 14, and the like. Various measuring instruments (not shown) are installed on the bus 12 for the purpose of protection, control and monitoring of the electric power system 2, and the measurement results of these measuring instruments are transmitted via the communication network 3 to the power supply and demand planning device. 1.

The power supply and demand planning device 1 is a general-purpose device including a CPU (Central Processing Unit) 21, a memory 22, a storage device 23, a communication device 24, an input device 25, and a display device 26, which are interconnected via an internal bus 20. It consists of computer equipment.

The CPU 21 is a processor that comprehensively controls the operation of the power supply and demand plan creation device 1 . The memory 22 is composed of semiconductor memories such as ROM (Read Only Memory) and RAM (Random Access Memory), and is used as a working memory for the CPU 21 .

The storage device 23 is composed of a large-capacity non-volatile storage device such as a hard disk device or an SSD (Solid State Drive), and stores various programs and data to be retained for a long period of time. The program stored in the storage device 23 is loaded into the memory 22 when the power supply and demand plan creation apparatus 1 is started or when necessary, and the CPU 21 executes this program to perform various functions of the power supply and demand plan creation apparatus 1 as a whole as described later. Processing is performed.

The communication device 24 is composed of, for example, a NIC (Network Interface Card) or the like, and performs reception processing for receiving measurement results transmitted from various measuring instruments in the electric power system 2 . In addition to these various measuring instruments, the communication device 24 also includes a weather system owned by the Japan Meteorological Agency or a weather information provider, an electric power market system for trading electric power in the electric power trading market, and a virtual power plant (VPP). It also communicates with a computer device of an aggregator that monitors and controls a plurality of distributed power sources and consumers.

The input device 25 is composed of a keyboard, a mouse, etc., and is used by the user to input instructions and information to the power supply and demand planning apparatus 1 . The display device 26 is composed of a liquid crystal display or an organic EL (Electro-Luminescence) display, and is used to display various necessary information. Note that the input device 25 and the display device 26 may be configured by a touch panel in which these functions are integrated.

(1-2) Power Supply and Demand Plan Creation Function According to the Present Embodiment Next, the power supply and demand plan creation function according to the present embodiment installed in the power supply and demand plan creation apparatus 1 will be described.

This power supply and demand planning function evaluates the stability of the power system against each assumed accident at each time based on the operation status of each device in the target power system 2, and the power system at the time when it is evaluated as unstable. Stabilization measures for stabilizing the power system 2 are created for each combination of the operation conditions of 2 and the assumed accident (hereinafter referred to as an unstable case), and for each stabilization measure created, the relevant This is a function that creates a stabilization operation constraint equation that approximates a stabilization measure, and creates a supply and demand plan using mathematical optimization technology etc. so that all the created stabilization operation constraint equations are satisfied.

With such a power supply and demand plan creation function, it is no longer necessary to consider the characteristics of the power system 2, which requires complicated calculations, when calculating the power supply and demand plan. It is possible to create

As a means for realizing the power supply and demand plan creation function of the present embodiment as described above, as shown in FIGS. and the supply and demand plan database 40 are stored, and the memory 22 includes an initial demand plan creation unit 50, a system stability evaluation unit 51, a system stabilization condition extraction unit 52, and an approximate constraint condition creation unit 56, which constitute a system stabilization supply and demand plan unit 56 A unit 53, a supply and demand plan creation unit 54, and a screen display/result storage unit 55 are stored.

In the system information database 30, system information 31 such as the configuration of the power system 2 and the maximum transmission capacity of the interconnection line, and various system accidents assumed in the power system 2 (hereinafter referred to as assumed accidents) are stored. and assumed accident information 32, which is information on various system disturbance cases for evaluating the stability of the power system 2 in the event of an accident.

The supply and demand plan database 40 stores power generator information 41, periodic inspection information 42, supply and demand information 43, controllability information 44, renewable energy information 45, initial supply and demand plan information 46, and stabilizing operation constraint information 47. there is

The generator equipment information 41 is information representing the characteristics of each generator existing in the electric power system 2, and the periodic inspection information 42 is various types of information regarding periodic inspection of the generators. The supply and demand information 43 is information such as the amount of power generation required for each time in the power system 2, and the controllability information 44 is information regarding controllability for adjusting fluctuations from an assumed state.

Further, the renewable energy information 45 is information such as the power generation amount and characteristics of the renewable energy in the electric power system 2, and the initial supply and demand plan information 46 is information on the supply and demand plan prepared in advance by oneself and others. Note that the initial supply and demand plan information 46 may not be stored in the supply and demand plan database 40 in some cases. Further, the stabilizing operation constraint information 47 is information representing the correspondence relationship between stabilization measures and stabilizing operation constraint expressions.

On the other hand, when the initial supply and demand plan information 46 is stored in the storage device 23, the initial supply and demand plan creation unit 50 reads the initial supply and demand plan information 46, provides it to the system stability evaluation unit 51, is not stored in the initial supply and demand plan information 46, an initial supply and demand plan (hereinafter referred to as the initial supply and demand plan) is created without considering the stability of the power system 2, and that information is used as the initial supply and demand plan. It is a program having a function of providing the system stability evaluation unit 51 as plan information.

The system stability evaluation unit 51 is a program having a function of evaluating the stability of the electric power system 2 when an assumed accident occurs in the electric power system 2 based on the assumed accident information 32 stored in the storage device 23. be.

In practice, the system stability evaluation unit 51 uses the initial supply and demand plan information 46 (first time only) provided by the initial supply and demand plan creation unit 50 and the supply and demand plan information provided by the supply and demand plan creation unit 54 to be described later. It extracts the starting state (starting or stopping) of the generator and the amount of output power. In addition, the system stability evaluation unit 51 constructs an analysis model of the power system 2 at each time based on the extracted information and the system information 31 and the power generator information 41 stored in the storage device 23. do. Then, the system stability evaluation unit 51 uses the constructed analysis model for each time to evaluate the stability of the power system 2 when the assumed accident occurs in the power system 2 for each assumed accident and for each time. The system stabilization condition extraction unit 52 is notified of the result.

The system stabilization condition extraction unit 52 is a program having a function of calculating stabilization measures for each unstable case evaluated as unstable by the system stability evaluation unit 51 . The system stabilization condition extraction unit 52 notifies the approximate constraint condition creation unit 53 of the calculated stabilization measures for each unstable case.

The approximation constraint condition creation unit 53 uses the stabilization measures for each unstable case notified from the system stabilization condition extraction unit 52, and the supply and demand plan creation unit 54 creates a supply and demand plan in consideration of the stabilization of the power system 2 as described later. It is a program that has a function that approximates each of the stabilization operation constraint equations that can be used when creating The approximate constraint condition creation unit 53 notifies the supply and demand plan creation unit 54 of the approximated stabilizing operation constraint equation for each unstable case.

The supply and demand plan creating unit 54 is a program having a function of creating a demand and supply plan so as to satisfy all stabilizing operation constraint expressions notified from the approximation constraint condition creating unit 53 so far. The supply and demand plan created by the supply and demand plan creation unit 54 is notified to the system stability evaluation unit 51, after which the system stability evaluation unit 51, the system stabilization condition extraction unit 52, the approximate constraint condition creation unit 53, and the supply and demand plan creation unit At 54, a process similar to that described above is repeated until a demand and supply plan is developed that allows the power system 2 to maintain stability for all possible faults at all times.

The screen display/result storage unit 55 performs the iterative processing by the system stability evaluation unit 51, the system stabilization condition extraction unit 52, the approximate constraint condition creation unit 53, and the supply and demand plan creation unit 54 described above. This program has a function of saving the supply and demand plan in the storage device 23 and displaying it on the display device 26 when the supply and demand plan is created so that the power system 2 can maintain stability in the event of an accident.

(1-3) Flow of processing related to the power supply and demand plan creation function of the present embodiment FIG. flow. This supply and demand plan creation process is triggered by the fact that the user inputs a supply and demand plan creation process execution command (hereinafter referred to as a demand and supply plan creation process execution command) via the input device 25 (FIG. 1). be.

In practice, when such a supply and demand plan creation processing execution command is input to the power supply and demand plan creation device 1, first, the initial supply and demand plan creation unit 50 generates system information 31, power generator information 41, and Based on the supply and demand information 43, an initial supply and demand plan is created without considering the stability of the power system 2, and information of the created initial supply and demand plan (initial supply and demand plan information) is output to the system stability evaluation unit 51 (S1 ). However, when the initial supply and demand plan information 46 is stored in advance in the storage device 23 as described above, the initial supply and demand plan creation unit 50 reads this initial supply and demand plan information 46 and sends it to the system stability evaluation unit 51. Notice.

Subsequently, the system stability evaluation unit 51 constructs an analysis model of the power system 2 at each time based on the initial supply and demand plan information notified from the initial supply and demand plan creation unit 50 (S2).

Specifically, the system stability evaluation unit 51 extracts the electrical circuit information of the power system, such as the impedance of transmission lines and the connection relationship, from the system information 31 stored in the storage device 23 . In addition, the system stability evaluation unit 51 includes the initial supply and demand plan information given from the initial supply and demand plan creation unit 50 in step S1, or the supply and demand plan information given by the supply and demand plan creation unit 54 in step S9 described later, and the storage device 23, based on the periodical inspection information 42 stored in 23, each generator that is activated at each time and its output power amount are acquired, and the dynamic characteristics of each activated generator are obtained. Information is extracted from the generator equipment information 41 stored in the storage device 23 .

Furthermore, the system stability evaluation unit 51 obtains necessary information about all renewable energy power generation facilities in the power system 2 from the renewable energy information 45, The supply and demand information 43 regarding the power system 2 and the controllability information 44 regarding the controllability of the electric power system 2 are read from the storage device 23 .

Based on the various information thus acquired, the system stability evaluation unit 51 constructs an analysis model of the power system 2 according to the operation status at each time.

Next, the system stability evaluation unit 51 evaluates the stability of the power system 2 for each assumed accident using the analysis model of the power system 2 at each time created in step S2 (S3). Specifically, the system stability evaluation unit 51 reads out the assumed accident information 32 from the storage device 23, generates an assumed accident at each time in the analysis model of the power system 2 for each time constructed in step S2, and The transient response of the power system 2 when an assumed accident occurs with respect to the operation status of the power system 2 is calculated as an evaluation result of the stability of the power system 2 against the assumed accident.

After that, the system stability evaluation unit 51 calculates the stability of the power system 2 for each assumed accident at each time calculated in step S3, and the system preset for all assumed accidents at all times. It is determined whether or not the stability standard (hereinafter referred to as the system stability standard) is satisfied, that is, whether or not the power system 2 is stable at all times and after all assumed faults have occurred (S4 ).

In addition, in the evaluation of the stability of the power system 2 against the assumed accident using such an analysis model, for example, the existing stabilization system disclosed in Non-Patent Document 4 is simulated on the analysis model, and the existing stabilization system stabilizes It may also be determined that the power system 2 is unstable when the power system 2 cannot be made stable, or when an undesirable operation occurs, such as when countermeasures require a great deal of cost.

Then, when a negative result is obtained in the determination in step S4, the system stability evaluation unit 51 determines the system stability obtained in step S3 for each case (unstable case) in which the power system 2 becomes unstable. is notified to the system stabilization condition extraction unit 52.

The system stabilization condition extraction unit 52 selects one unstable case for which step S6 and subsequent steps are unprocessed from among the unstable cases for which the system stability evaluation result has been notified from the system stability evaluation unit 51 (S5 ).

In addition, the system stabilization condition extraction unit 52 adjusts the output and activation state (start or stop) of the specific device for the unstable case selected in step S5 (hereinafter referred to as the selected unstable case). A stabilization measure is calculated for changing the state of the power system 2 from the unstable state to the stable state (S6). At this time, device constraints that affect multiple times, such as continuous activation time constraints and output change speed, are considered in step S9 described later, and are not considered in step S6. to calculate.

It should be noted that the methods disclosed in Non-Patent Document 3 and Non-Patent Document 5 are examples of methods for calculating such stabilization measures. As in these methods, the dynamic characteristics of the power system 2 are represented by differential equations and difference equations, and the power system 2 An economical stabilization measure may be calculated while taking into consideration the dynamic characteristics of .

Also, when adjusting up to the start/stop of each device, introduce a discrete variable u _it that indicates whether to start/stop 0: stop, 1: start, and enable the output P _it only when u _it = 1 A constraint condition of P _max u _it ≧P _it may be added. Further, the target of adjustment is not limited to the synchronous generator, and may include stopping or curtailing the output of distributed power sources such as renewable energy equipment.

When the start/stop of each device is adjusted, it is possible to calculate the optimum device operation that maintains stability in the assumed accident targeted for device operation at the adjusted target time. On the other hand, if the order of measures and methods in the stabilization measures have already been determined as operation rules, the measures may be applied until stabilization is achieved based on these rules. Extraction of these stabilization measures is carried out for each of the operating conditions and the system accident at the time evaluated as unstable in step S.

In the processing up to this point, the stabilization measures are calculated for each hypothetical accident that has become unstable under the operating conditions at each time. , continuous operation constraints of output and activation state between times before and after countermeasures are not taken into consideration.

For this reason, from the next step onwards, each stabilization measure targeting multiple specified power generators will be stabilized not for specific power generators, but for any number of power generators, such as inertial force and short-circuit capacity in the specified area exceeding thresholds. Create an approximate stabilization operation constraint formula that satisfies the conditions of By considering these approximate stabilizing operation constraint equations in the supply and demand plan, it is assumed that the above continuous operation constraint is also satisfied.

Subsequently, the approximation constraint condition creation unit 53 approximates the stabilization measure calculated by the system stabilization condition extraction unit 52 in step S6 to the stabilizing operation constraint expression described above for stably operating the power system 2. (S7).

FIG. 4 shows specific processing contents of the approximation constraint condition creating unit 53 in step S7. According to the processing procedure shown in FIG. 4, the approximation constraint condition creating unit 53 first classifies the type of unstable phenomenon in the selected unstable case into one of several predetermined types (S20).

Types of such instability phenomena include deterioration of "transient stability", deterioration of "voltage stability", and deterioration of "frequency stability". "Transient stability" is determined based on the internal phase difference of the generator, presence or absence of step-out, etc., and "voltage stability" is determined based on the amount of voltage drop, voltage phase difference between points, and the like. "Frequency stability" is determined based on the amount of fluctuation in the frequency of the voltage system.

Next, the approximation constraint condition creation unit 53 determines the magnitude of the change in the operating conditions before and after applying the stabilization measure to the selected unstable case calculated in step S6 of the supply and demand plan calculation process, that is, the amount of change for stabilization. , and extracts the change points for the equipment adjusted to (S21). Note that such changes may include starting or stopping of equipment, changes in output, and changes in power flow if the equipment is a transmission line. Since the adjustment content and its scale differ depending on the device, priority may be set according to the adjustment content of the adjusted device, and devices with lower priority may be ignored.

Next, based on the classification result in step S20 and the change points (adjusted equipment and its adjustment details) extracted in step S21, the approximate constraint condition creation unit 53 stores in the storage device 23, for example, FIG. The classification of stabilization measures is determined by referring to the stabilization operation constraint information 47 configured as shown in (S22).

The stabilization operation constraint information 47 approximates the type of unstable phenomenon, the stabilization measure calculated for the unstable phenomenon, the classification of the stabilization measure, and the corresponding stabilization measure. This is information representing a correspondence relationship with the stabilization operation constraint formula, and is created in advance by a user or the like.

In the example of FIG. 5, for example, the type of unstable phenomenon is "transient stability", and the stabilization measure calculated by the system stabilization condition extraction unit 52 for the unstable phenomenon is "unstable generator prior output suppression (preliminarily suppressing the output of unstable generators)”, the stabilization measure is classified into the category of “preliminary output suppression of unstable generators”, and its stabilization It is shown that the stabilization operation constraint expression that approximates the countermeasure is "P _it ≤ P _{it threshold} (restricts the active power output P _it of the generator (equipment i) to a predetermined threshold P _{it threshold} or less)". there is

In FIG. 5, P _it represents the active power output of device i at time t, and P _{it threshold} represents a preset P _it threshold. Also, the P _{flow threshold} represents a preset threshold for the power flow of the corresponding transmission line. Furthermore, Mi represents the inertia constant of device i, and u _it indicates whether or not device i has been activated at time t. is a discrete variable with Also, the M threshold is a preset threshold of the inertial force of the corresponding area.

Yi represents the coefficient vector of admittance that includes the back impedance of device i, which is a generator, and calculates the short-circuit current, V _{it ref} is the target voltage of the generator, and Ithreshold is the _threshold of the short-circuit current in the target area. show. Furthermore, F _PTDFi represents a coefficient vector when calculating the power flow of the transmission line from the output of device i.

Q post- _{accident i} represents the amount of reactive power that device i can supply after the accident, taking control responsiveness into consideration. This amount of reactive power is smaller in inverter devices such as distributed power sources than in existing power generators. Also, the Q threshold represents the threshold of the amount of reactive power set for the corresponding device i. Furthermore, P _balance (P _it ) represents a function of the frequency control power ensured at time t by the generator, device i, depending on the output, and the P _{balance threshold} is preset for such frequency control power. represents the threshold

By the way, the classification of stabilization measures here and the stabilization operation constraint expression extracted in the next step S23 are not the adjustment of a specific device as in the above-mentioned steps S6 and S21, but the stabilization with a plurality of arbitrary devices. Classification of stabilization measures and stabilization operation constraint equations that satisfy the conditional constraint equations.

Subsequently, the approximate constraint condition creation unit 53 creates an approximate stabilizing operation constraint expression for the stabilization measure from the stabilizing operation constraint information 47 based on the determination result of the classification of the stabilization measure determined in step S22. Extract (S23).

Note that the stabilizing operation constraint formula extracted in step S23 includes a threshold. For this reason, the approximate constraint condition creation unit 53 applies the stabilization measures calculated by the system stabilization condition extraction unit 52 in step S6 to the threshold contained in the stabilization operation constraint expression extracted in step S23 for the selected unstable case. It is calculated from the operating conditions after the operation (S24).

For example, when the classification of the stabilization measure is "the short-circuit capacity in the specific area is equal to or greater than the threshold", the approximate constraint condition creation unit 53 creates an analysis model of the power system 2 that assumes the operating conditions after the stabilization measure is applied. is constructed, the short-circuit capacity is calculated from the analysis result using the constructed analysis model, and this is set as the threshold value (I _{threshold value} in the example of FIG. 6).

If all the incomplete cases have not been completed by the processing up to this point (S8: NO), the processing returns to step S5, and from this step onwards, steps S5 to S8 are performed until a positive result is obtained in step S7. The process is repeated.

Then, when the stabilization measures for all the incomplete cases are eventually approximated to the stabilization operation constraint equation (S8: YES), the supply and demand planning unit 54 stabilizes each unstable case obtained so far. A supply and demand plan is created by applying all operational constraint formulas (S9).

で与えられる目的関数F(P,u)を最小化する各発電機の起動状態（起動又は停止）や発電出力を求める最適化問題を解くことにより行う。 In the case of this embodiment, the supply and demand plan is created while satisfying all of the stabilization operation constraint equations for each unstable case, and economic indicators such as power generation costs (power generation costs and start-up costs for all generators within the planned time period). ) is expressed by the following expression

This is done by solving an optimization problem to find the starting state (starting or stopping) of each generator and the power generation output that minimizes the objective function F(P,u) given by.

In equation (1), T _end is the end time of the supply and demand plan, N _gen is the number of generators, a _i , bi , and c _i are the power generation cost coefficients of the _i -th generator, P _it is the i-th The power output of the generator at time t, u _it is a discrete variable of “0” or “1” representing the starting state of the i-th generator at time t (starting is “1”, stopping is “0”), Δu _It is a discrete variable that takes 1 at the start time of the i-th power generator at time t and 0 otherwise, and SUC _i represents the start-up cost of the i-th power generator.

As operational constraints for such an optimization problem, in addition to the operational constraints shown in FIG. It is possible to calculate the supply and demand plan that minimizes the power generation cost while satisfying the operation of the equipment and the equipment output and the start state.

The optimization problem of formula (1) is composed of discrete variables of "0" and "1", continuous variables, and quadratic or linear terms, and is called a mixed integer programming problem in mathematical optimization. is a problem. This mixed integer programming problem can be solved by utilizing mathematical optimization methods such as the methods disclosed in Non-Patent Documents 1 and 2 and commercially available mathematical optimization solvers.

When complex functions are involved in optimization problems other than mixed integer programming problems, it is difficult to apply mathematical optimization techniques, and even if they are applied, the computation time is enormous. In considering the stabilization of the power system 2, in the dynamic characteristics of the generator etc. in the power system 2, not only transfer functions but also output saturation, trigonometric functions, complex functions with strong nonlinear elements such as products and divisions of different variables , these characteristics of the power system 2 cannot be applied to mathematical optimization. Therefore, in the present embodiment, the dynamic characteristics and stability of the power system 2 are evaluated in the process of steps S1 to S6, and the stability of the power system 2 is approximated by a stabilizing operation constraint equation. Therefore, it is possible to create a supply and demand plan that satisfies system stability in a practical calculation time without requiring complicated calculations required for stabilizing the power system 2 in the optimization problem.

After calculating the supply and demand plan by adding the approximate stabilization operation constraint expression in step S9, by executing steps S2 and S3 as described above based on the calculated supply and demand plan, the analysis model at each time and determine whether or not the preset system stability criteria are satisfied in all postulated accidents at all times.

If not satisfied, steps S5 to S9 are executed in the same manner as described above, and then steps S2 to S9 are repeated until a positive result is obtained in step S4. At this time, the stabilizing operation constraint equations calculated in step S7 by the approximation constraint condition creation unit 53 are sequentially and cumulatively added to create a supply and demand plan. be improved.

Eventually, when a positive result is obtained in step S4 by creating a supply and demand plan that satisfies the system stability criteria for all assumed accidents at all times, the screen display/result storage unit 55 displays the supply and demand plan. The information is displayed on the device 26 (FIG. 1) and stored in the storage device 23 (FIG. 1) as supply and demand plan information. In addition, the screen display/result storage unit 55 displays on the display device 26 the difference between the supply and demand plan and the initial supply and demand plan, and the classification of the stabilizing operation constraint expression or stabilization measure corresponding to the time when the difference exists. , the changes in the supply and demand plan and the reasons for the changes to ensure stabilization are reported to the user (S10). This completes the supply and demand plan calculation process.

(1-4) Effect of this embodiment As described above, the power supply and demand plan creation device 1 of this embodiment evaluates the stability of the power system 2 for each assumed accident at each time, and generates an unstable case. Calculate stabilization measures for each of the extracted unstable cases, calculate stabilization operation constraint equations that approximate the safety measures for each calculated safety measure, and use the calculated stabilization operation constraint equations. and create a supply and demand plan using mathematical optimization technology.

Therefore, according to the power supply and demand plan creation device 1, it is no longer necessary to consider the nonlinear characteristics of the power system, which require complicated calculations, when calculating the power supply and demand plan, and the stability of the power system 2 is ensured in a practical calculation time. It is possible to create a demand and supply plan based on

In addition, in the power supply and demand planning apparatus 1, such a series of processing is repeated until there are no more unstable cases. The optimal solution is extracted from the Optimality can be improved and economic efficiency can be improved compared to creating a stable supply and demand plan while modifying a part of the plan.

Furthermore, according to this electric power supply and demand plan creation device 1, it is possible to determine how the supply and demand plan, which considers only the initial generator operation constraints and economic efficiency, is classified into unstable phenomena and their stabilization measures identified for each iteration. Since a supply and demand plan that ensures stability from various perspectives is shown, it is also possible to obtain explanations in the supply and demand plan.

(2) Second Embodiment FIG. 7, in which parts corresponding to those in FIG. 1 are denoted by the same reference numerals, shows an electric power supply and demand planning apparatus 60 according to a second embodiment. This power supply and demand plan creation device 60 has an additional expected disturbance creation unit 61 as a program, and along with this, the system stability evaluation unit 62 and the screen display/result storage unit 63 are partially different in function. It is configured in the same manner as the power supply and demand planning apparatus 1 according to the first embodiment except for the points.

The expected disturbance addition creation unit 61 creates the initial supply and demand plan created by the initial supply and demand plan creation unit 50 or the supply and demand plan created by the supply and demand plan creation unit 54, and changes in output of equipment according to weather changes assumed at each time. Alternatively, it is a program having a function of constructing an analysis model of the electric power system 2 for each time and for each assumed disturbance using the imbalance amount as an assumed disturbance, and outputting the model to the system stability evaluation unit 62 .

Then, the system stability evaluation unit 62 uses the analysis model of the power system 2 for each time and each assumed disturbance given from the assumed disturbance addition creation unit 61 and the initial supply and demand plan or the supply and demand plan created by the initial supply and demand plan creation unit 50 The stability of the power system 2 is evaluated for each combination of time, assumed accident, and assumed disturbance based on the analysis model for each time and for each assumed accident constructed based on the supply and demand plan created by the creating unit 54 . The screen display/result storage unit 63 also displays the results on the display device 26 and stores the results in the storage device 23, including cases in which the expected disturbances added by the expected disturbance addition creation unit 61 are added.

FIG. 8 shows a specific flow of supply and demand plan creation processing executed in the power supply and demand plan creation device 60 of the present embodiment in relation to the above function (power supply and demand plan creation function). This supply and demand plan creation process is triggered by input of an execution command for the supply and demand plan creation process (demand and supply plan creation process execution command) via the input device 25 by the user.

In practice, when such a supply and demand plan creation process execution command is input to the power supply and demand plan creation device 60, first, the initial supply and demand plan creation unit 50 generates system information 31, power generator information 41, and Based on the supply and demand information 43, the initial supply and demand plan is created without considering the stability of the power system 2, and the information of the created initial supply and demand plan (initial supply and demand plan information) is used by the system stability evaluation unit 51 and the assumed disturbance additional creation. Output to the unit 61 (S30). However, when the initial supply and demand plan information 46 is stored in advance in the storage device 23 as described above, the initial supply and demand plan creation unit 50 reads out this initial supply and demand plan information 46, and the system stability evaluation unit 51 and The expected disturbance addition creation unit 61 is notified.

Subsequently, the system stability evaluation unit 62 and the assumed disturbance addition creation unit 61 construct an analysis model of the power system 2 for each time (S31).

In practice, the system stability evaluation unit 62 constructs an analysis model of the power system 2 at each time based on the initial supply and demand plan information notified from the initial supply and demand plan creation unit 50 in the same manner as in step S2 of FIG. (S31A).

In parallel with this, the expected disturbance addition creation unit 61 responds to various patterns of situation changes such as weather and temperature changes with respect to the equipment scheduled to be started in the supply and demand plan, and the situation changes occur for each of these situation changes. An analysis model for each time of the power system 2 in the case where the power system 2 is generated is constructed, and each constructed analysis model for each time is output to the system stability evaluation unit 62 (S31B).

Specifically, in the supply and demand plan created in step S30 or step S38 described later, there are devices such as a photovoltaic power generation system and a wind power generation device whose power generation amount changes due to the influence of weather. The creating unit 61 first extracts from the supply and demand plan the start-up period of equipment whose output changes based on weather changes.

Next, the expected disturbance additional creation unit 61 is affected by the weather (weather and climate) in the above-described startup period based on the probability elements such as the probability of precipitation in the extracted weather information. Calculate the output of each device whose power generation amount changes.

As a method for assuming changes in weather and climate, a Monte Carlo simulation is applied, in which the probability distribution of weather changes at each time is calculated in advance using a forecasting method, and scenarios for weather changes are created based on the probabilities. Just do it.

In renewable energy power generation equipment such as photovoltaic power generation systems and wind power generators, maximum power point tracking (MPPT) control that maximizes power generation according to the weather is applied, so in steps S30 and S38 is larger than the output by MPPT control, the output may be set to the output by MPPT control according to each weather scenario.

On the other hand, for a power source that consists of multiple devices such as storage batteries and renewable energy generators, it is possible to construct an analytical model for these power sources and calculate the output through the analytical model for each weather scenario described above. good. In the simple analysis model, when the electricity market price is low, the storage battery is charged with the power output of the renewable energy generator according to MPPT control, and when the electricity market price is high, the power output of the renewable energy generator is charged. And it may be constructed so as to discharge the storage battery. These output calculations assume that the characteristics of the renewable energy power generation equipment are known, and calculate the output of the equipment according to the weather scenario.

On the other hand, if the characteristics of such renewable energy power generation equipment are unknown, the relationship between the past weather information and the imbalance amount, which is the error between the planned output and the actual output at that time, can be analyzed using multiple regression analysis. A learning model trained using techniques such as deep learning is created, and the amount of imbalance according to the weather scenario is calculated by the learning model. When this imbalance amount is calculated, the output may be increased or decreased by the imbalance amount with respect to the output in step S30 or step S38.

Then, as in the first embodiment, the equipment output according to this weather scenario is readjusted, including other equipment, so as to meet the supply and demand operation conditions, and the power is adjusted according to the operation status for each time. Construct an analysis model for each of system 2.

Subsequently, the system stability evaluation unit 62 uses the analysis model of the power system 2 at each time created in step S31A and each analysis model of the power system 2 corresponding to the operation status at each time created in step S31B. Then, the stability of the power system 2 for each assumed accident is evaluated (S32).

Specifically, the system stability evaluation unit 62 reads out the assumed accident information 32 from the storage device 23, and generates the analysis model of the power system 2 for each time created in step S31A and the power system 2 for each time created in step S31B. The assumed accident is generated in each of the analysis models, and the transient response of the power system 2 when the assumed accident occurs with respect to the operation status of the power system 2 at each time is calculated. Calculated as stability evaluation results.

Thereafter, steps S33 to S38 are executed in the same manner as steps S4 to S9 in the supply and demand plan calculation process of the first embodiment described above with reference to FIG. 3 to create a supply and demand plan. By executing steps S31 and S32 as described above, an analysis model for each time is constructed, and whether or not the preset system stability criteria are satisfied for all assumed accidents at all times It judges (S33).

If not satisfied, steps S34 to S38 are executed in the same manner as described above, and then the processing of steps S31 to S38 is repeated until a positive result is obtained in step S33. At this time, the supply and demand plan is created by sequentially adding the stabilizing operation constraint expressions calculated in step S36 by the approximate constraint condition creation unit 53, thereby improving the safety of the electric power system 2 compared to the previous supply and demand plan. .

Then, when a positive result is obtained in step S33 by creating a demand-supply plan that satisfies the system stability criteria for all assumed accidents at all times, the screen display/result storage unit 55 displays the demand-supply plan. is displayed on the display device 26 (FIG. 7), and the information is stored in the storage device 23 (FIG. 7) as supply and demand plan information. In addition, the screen display/result storage unit 55 displays on the display device 26 the difference between the supply and demand plan and the initial supply and demand plan, and the classification of the stabilizing operation constraint expression or stabilization measure corresponding to the time when the difference exists. , the changes in the supply and demand plan and the reasons for the changes for ensuring stabilization are reported to the user (S39). This completes the supply and demand plan calculation process.

According to the power supply and demand plan creation device 60 of the present embodiment described above, the power supply and demand plan is created taking into consideration the stability of the power system while also considering the output or imbalance amount of each device that changes according to the weather conditions. can do. In this case, methods including nonlinear elements such as multiple regression analysis and deep learning are used to calculate equipment output and imbalance amount according to the weather. Factors are difficult to consider. Regarding this point, according to the electric power supply and demand plan creating apparatus 60 of the present embodiment, in addition to the effect obtained by the first embodiment, it has the effect of being able to consider an assumed disturbance according to the equipment operation of the supply and demand plan. Obtainable.

(3) Other Embodiments In the above-described first and second embodiments, the case where the power supply and demand plan creation devices 1 and 60 are configured by one computer device was described, but the present invention is not limited to this, the functions of the power supply and demand planning apparatus 1, 60 may be distributed and installed in a plurality of computer apparatuses that constitute a distributed computing system.

Further, in the above-described first and second embodiments, the processing of steps S3 to S7 of the supply and demand plan calculation processing of the first embodiment described above with reference to FIG. 3, and the second implementation described above with reference to FIG. A case has been described in which the processing of steps S32 to S36 of the demand and supply plan calculation processing in the form of is executed by one power supply and demand plan creation device 1, 60, but the present invention is not limited to this, and steps S2 and Evaluation of the stability of the power system 2 for each time and for each assumed accident using the analysis model for each time created in step S31 is an independent process for each evaluation, so it is executed in parallel by a plurality of computer devices. You may do so. By doing so, it is possible to further shorten the calculation time.

INDUSTRIAL APPLICABILITY The present invention can be widely applied to power supply and demand plan creation apparatuses of various configurations for creating a power supply and demand plan in a target power system.

Reference Signs List 1, 60 Power supply and demand planning device 2 Power system 21 CPU 31 System information 32 Assumed accident information 41 Generator equipment information 42 Regular inspection information 43 ……Supply and demand information, 44……Adjustability information, 45……Renewable energy information, 46……Initial supply and demand plan information, 47……Stabilization operation constraint information, 50……Initial supply and demand plan creation unit, 51, 62 . Assumed disturbance addition creation part.

Claims (12)

In a power supply and demand plan creation device that creates a power supply and demand plan in a target power system,
A system stability evaluation unit that evaluates the stability of the power system for each assumed accident at each time;
A system stabilization condition extraction unit that creates a stabilization measure for stabilizing the power system for each unstable case that is a combination of the time and the assumed accident evaluated as unstable by the system stability evaluation unit;
an approximation constraint condition creation unit that approximates the stabilization measures for each unstable case created by the system stabilization condition extraction unit to a stabilization operation constraint expression;
and a demand and supply plan creating unit that creates the demand and supply plan so as to satisfy all of the stable operation constraint expressions for each of the unstable cases approximated by the approximate constraint condition creating unit. . The supply and demand plan created by the supply and demand plan creation unit is given to the system stability evaluation unit,
The system stability evaluation unit,
Based on the operation status of each device in the supply and demand plan given from the supply and demand plan creation unit, evaluate the stability of the power system for each assumed accident at each time,
The processing by the system stabilization condition extraction unit, the approximate constraint condition creation unit, the supply and demand plan creation unit, and the system stability evaluation unit is repeated until the unstable case disappears,
The supply and demand planning unit,
All the cumulatively created by the approximate constraint condition creation unit each time the processing by the system stabilization condition extraction unit, the approximate constraint condition creation unit, the supply and demand plan creation unit, and the system stability evaluation unit is repeated The power supply and demand plan creation device according to claim 1, wherein the supply and demand plan is created so as to satisfy a stable operation constraint expression. The system stabilization condition extraction unit,
creating the stabilization measure designating a particular device for each unstable case;
The approximation constraint creation unit
2. The power supply and demand plan creation device according to claim 1, wherein the stabilizing operation constraint expression that constrains the conditions related to the stability of the power system is created by an arbitrary device based on the stabilizing measures. The approximation constraint creation unit
2. The power supply and demand plan creation device according to claim 1, wherein the threshold value included in the stabilizing operation constraint expression is calculated from the operating conditions of the power system after applying the corresponding stabilizing measure. 2. The power supply and demand plan creation apparatus according to claim 1, further comprising a screen display unit that displays changes in the supply and demand plan and reasons for changes for ensuring stabilization. Assumed disturbance additional creation unit for constructing an analysis model of the power system for each time and for each of the assumed disturbances at each time, using the output change or imbalance amount of the equipment according to the weather change assumed at each time as the assumed disturbance. with
The system stability evaluation unit,
The power supply and demand plan creation device according to claim 1, wherein the stability of the power system for each assumed accident at each time is evaluated by also using each of the analysis models constructed by the assumed disturbance addition creation unit. . A power supply and demand plan creation method executed by a power supply and demand plan creating device for creating a power supply and demand plan in a target power system,
a first step of evaluating the stability of the power system for each postulated fault at each time;
a second step of creating a stabilization measure for stabilizing the power system for each unstable case consisting of a combination of the time evaluated as unstable and the assumed accident;
a third step of approximating each of the created stabilization measures for each of the unstable cases to a stabilization operation constraint equation;
and a fourth step of creating the supply and demand plan so as to satisfy all of the stabilizing operation constraint expressions for each of the approximated unstable cases. Further comprising a fifth step of evaluating the stability of the power system for each assumed accident at each time based on the created supply and demand plan,
The processing of the second to fifth steps is repeated until the unstable case disappears,
In the fourth step,
The supply and demand plan is created so as to satisfy all the stabilizing operation constraint expressions cumulatively created in the third step each time the processing of the second to fifth steps is repeated. The power supply and demand plan creation method according to claim 7. In the second step,
creating the stabilization measure designating a particular device for each unstable case;
In the third step,
8. The power supply and demand plan creation method according to claim 7, wherein, based on the created stabilization measure, the stabilization operation constraint expression that constrains the conditions regarding the stability of the power system is created by an arbitrary device. . In the third step,
8. The power supply and demand plan creation method according to claim 7, wherein the threshold included in the stabilizing operation constraint expression is calculated from the operating conditions of the power system after applying the corresponding stabilizing measure. 8. The electric power supply and demand plan preparation method according to claim 7, wherein changes in the supply and demand plan and reasons for the changes for ensuring stabilization are displayed. In the second step,
Construct an analysis model of the power system for each time and for each of the assumed disturbances at each time, using the output change or imbalance amount of the equipment according to the weather change assumed at each time as the assumed disturbance,
8. The power supply and demand plan creation method according to claim 7, wherein the constructed analysis models are also used to evaluate the stability of the power system for each assumed accident at each time.

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