JP7551360B2 - Supply and demand monitoring device, supply and demand adjustment device and method - Google Patents

Description

The present invention relates to a power system supply and demand monitoring device, a supply and demand adjustment device, and a method.

When a supply-demand imbalance occurs in a power system due to load fluctuations (including output fluctuations of renewable energy), frequency fluctuations occur. Currently, system operators adjust the supply-demand balance in a power supply area by combining economic load dispatch (ELD: Economic Load Dispatch) and load frequency control (LFC: Load Frequency Control) at the central load dispatch center to allocate output to regulating power sources. In this specification, the destination of output allocation in supply-demand adjustment is called an regulating power source. The regulating power source can be selected from at least one of a generator, a storage battery, and a demand response.

Economic load dispatch (ELD) is a function that determines the output dispatch of each regulated power source to follow the load, taking into account factors such as fuel costs, for load fluctuations of more than a dozen minutes. Load frequency control (LFC) is a function that calculates the amount of fluctuation for a load of a few minutes to a dozen minutes, and controls the system frequency within an acceptable range by commanding each regulated power source to generate power in accordance with this amount of fluctuation.

Furthermore, if a supply-demand adjustment market where adjustment capacity can be traded is created, grid operators will be able to procure adjustment capacity from this supply-demand adjustment market. In such operations, a mechanism for activating adjustment capacity based on merit order may be established. In output allocation based on merit order, output is allocated to adjustment power sources based on priority order, which is determined by cost. When increasing adjustment capacity, output is allocated in order of lowest cost, and when decreasing adjustment capacity, output is allocated in order of highest cost.

Figure 1 shows an example of output allocation for each regulating power source based on output allocation according to merit order. In this case, however, the regulating costs MA to ME of each regulating power source G (GA to GE) are assumed to be MA < MB < MC < MD < ME. This example imagines that a total of 80 upward regulating power is allocated to each regulating power source G (GA to GE) with an output allocable upper limit of 30. In this example of allocating upward regulating power, first, 30, which is the output allocable upper limit, is allocated to regulating power source GA, which has the lowest adjustment cost. Next, 30, which is the output allocable upper limit, is allocated to regulating power source GB, which has the second lowest adjustment cost. Finally, 20 is allocated to regulating power source GC, which has the second lowest adjustment cost.

At this time, it is assumed that output allocation will take into consideration not only the balance between supply and demand, but also the stability of the power system. In order to operate the power system stably, various constraints such as overload, voltage deviation, voltage stability, synchronous stability, and ensuring adjustment capacity must be resolved. In order to avoid violating such constraints, output is redirected from merit order allocation, sacrificing economic efficiency, but it is normal to operate in a way that does not violate constraints.

In other words, when considering the constraints on the stability of the power system, output may not be allocated according to the merit order as shown in Figure 1. Figure 2 shows an example of an allocation of regulated power sources that is not in merit order, where 30 is allocated to regulated power source GA, 5 to regulated power source GB, 25 to regulated power source GC, and 20 to regulated power source GD.

As the first constraint on stability, we will explain overload. An overload is when the power flow exceeds the capacity of the transmission line. Figure 3 shows an example of an overloaded transmission line. This transmission system has regulated power source G (from GA to GD) connected as shown in the figure, and the upper diagram shows an example where the power flow from regulated power source GB to load 1 is small. The lower diagram shows an example where the power flow in the direction towards load 1 has increased due to an increase in the output of regulated power source GD. Note that the system is operated in a way that prevents overload from occurring, for example by changing the output of the regulated power sources.

The second constraint on stability is voltage deviation. Voltage deviation occurs when the voltage at each node deviates from its upper or lower limit. Figure 3 shows an example where a node connected to load 3 has experienced a voltage deviation (deviating from the lower voltage limit). Note that the system is operated to prevent voltage deviations by appropriately adjusting the balance of reactive power, etc.

The third constraint on stability is voltage stability. Voltage stability is the ability to maintain a stable voltage during disturbances such as an increase in load or the shutdown of regulated power sources or substation equipment. Voltage stability becomes an issue due to the need to transmit large amounts of power over long distances due to remote and uneven distribution of power sources, increased reactive power losses, and changes in load characteristics (increase in constant power loads). Voltage stability is maintained by installing synchronous phase modifiers and static reactive power compensators that control voltage and reactive power.

As the fourth constraint on stability, we will explain synchronous stability. Synchronous stability is the ability to stably maintain synchronization between regulated power sources during disturbances such as the shutdown of a regulated power source. When a fault occurs in the power system due to a lightning strike or other cause, the rotation of some rotating machine-type regulated power sources accelerates relative to the other regulated power sources. The internal phase difference angle of the accelerated regulated power source with respect to the reference regulated power source becomes larger compared to the other regulated power sources, and synchronization between the regulated power sources cannot be maintained. Synchronous stability is maintained by disconnecting the accelerated regulated power source from the system and preventing the number of accelerating regulated power sources from increasing.

The fifth constraint on stability is ensuring the ability to adjust. Adjustment is the ability to change supply or demand in an upward or downward direction. This adjustment ability must be secured so that it can respond to demand forecast errors, time fluctuations, power outages, etc.

There is a technology disclosed in Patent Document 1 as a method for adjusting supply and demand in a power system. Patent Document 1 describes that it provides an electric power supply and demand control system, program, and method that enables supply and demand adjustment by merit order while taking into account not only economic load distribution (LFC) but also load frequency control (ELD), ensures fairness and transparency when procuring adjustment capacity, and exhibits excellent supply and demand control performance.

Also, as a method for adjusting supply and demand in a power system, there is a technology disclosed in Patent Document 2. Patent Document 2 states that by appropriately formulating one or both of the constraints of the transformer tap ratios of the parallel banks and the input amount of phase modifying equipment and incorporating them into the optimal power flow calculation, it is possible to shorten the calculation time and obtain a reasonable solution that conforms to actual operation as the result of the optimal power flow calculation regardless of the objective function.

JP 2019-187099 A Patent No. 5077316

However, in Patent Document 1, if only output allocation based on merit order is performed, there is a possibility that various constraints on the stability of the power system may not be satisfied.

In addition, although Patent Document 2 does not mention output allocation using the merit order method, it uses optimal power flow calculations to calculate so as not to violate constraints on the stability of the power system. It is possible to satisfy power stability such as overload, but it may not be possible to explain whether this is the most economical output allocation while satisfying stability constraints.

In light of the above, the present invention aims to provide a power system supply and demand monitoring device, supply and demand adjustment device, and method that can evaluate the validity of output allocation as to whether it is the most economical output allocation while satisfying stability constraints, and that can apply a cheaper output allocation pattern.

In view of the above, the present invention provides a "supply and demand monitoring device that determines output allocation patterns for multiple regulating power sources in a power system, comprising an output allocation pattern determination unit that determines multiple output allocation patterns that are less expensive in relation to an output allocation command value, a system analysis unit that performs a system analysis of the power system based on each of the multiple output allocation patterns from the output allocation pattern determination unit, and a stability determination unit that determines the stability of the power system when the multiple output allocation patterns are used as a result of the system analysis in the system analysis unit, and is characterized in that the supply and demand monitoring device is capable of evaluating the validity of whether the output allocation patterns of the multiple regulating power sources in the power system are the most economical output allocation while satisfying the stability constraints of the power system."

The present invention also provides a "supply and demand adjustment device that is provided with an output means in a supply and demand monitoring device and that is adapted to give output commands via a communication means to a plurality of regulated power sources in a power system, the output means selecting one output distribution pattern that is the most economical output distribution while satisfying the stability constraints of the power system, and giving output commands via the communication means to the plurality of regulated power sources."

The present invention also provides a "supply and demand monitoring method for determining output allocation patterns for a plurality of regulating power sources in a power system, which determines a plurality of output allocation patterns that are less expensive in relation to an output allocation command value, performs a system analysis of the power system based on each of the plurality of output allocation patterns, judges the stability of the power system for the plurality of output allocation patterns as a result of the system analysis, and enables an evaluation of the validity of whether the output allocation pattern of the plurality of regulating power sources in the power system is the most economical output allocation while satisfying the stability constraints of the power system."

The present invention also provides a "supply and demand adjustment method in which an output allocation pattern obtained by the supply and demand monitoring method is given as an output command to a plurality of regulating power sources in a power system, the method being characterized in that one output allocation pattern which is the most economical output allocation while satisfying the stability constraints of the power system is selected, and this is given as an output command to the plurality of regulating power sources."

The present invention makes it possible to evaluate the validity of output allocation as to whether it is the most economical output allocation while satisfying stability constraints, and to apply a cheaper output allocation pattern.

FIG. 13 is a diagram showing an example of output distribution according to a merit order. FIG. 1 is a diagram showing an example of a power system in which output allocation is not based on merit order as a result of taking into account stability constraints. FIG. 1 shows an example of a power system experiencing overload and voltage excursions. FIG. 1 is a block diagram showing a hardware configuration of a power system demand and supply monitoring device according to a first embodiment. FIG. 2 is a block diagram showing the functional configuration of the supply and demand monitoring device according to the first embodiment. 6 is a flowchart showing the process of the supply and demand monitoring device of FIG. 5 . 11 is a flowchart showing a first example of automatic determination of an output distribution pattern. FIG. 13 is a diagram showing a processing image of a first example of automatic output distribution pattern determination. 10 is a flowchart showing a second example of automatic determination of an output distribution pattern. FIG. 13 is a diagram showing a processing image of a second example of automatic output distribution pattern determination. FIG. 13 is a diagram showing an example of an output image regarding the output distribution pattern of regulating power sources and the results of stability analysis. FIG. 11 is a block diagram showing a hardware configuration of a power system demand and supply monitoring device according to a second embodiment. 13 is a flowchart showing the process of the supply and demand monitoring device of FIG. 12 . An example of an output image regarding the output distribution pattern of regulated power sources and the results of stability analysis is shown below. FIG. 11 is a block diagram showing a functional configuration of a supply and demand monitoring device according to a third embodiment. 16 is a flowchart showing the processing of the supply and demand adjusting device of FIG. 15 . FIG. 13 is a diagram showing an example of an output image regarding the output distribution pattern of regulating power sources and the results of stability analysis.

The following describes an embodiment of the present invention with reference to the drawings. Note that the embodiments described below do not limit the invention as claimed, and not all of the elements and combinations described in the embodiments are necessarily essential to the solution of the invention.

Figure 4 is a block diagram showing the hardware configuration of the power system supply and demand monitoring device according to the first embodiment. Figure 4 shows the power system 20 and the power system supply and demand monitoring device 10 connected to each point of the power system 20 via the communication network 300.

In FIG. 4, the supply and demand monitoring device 10 is configured, for example, as a computer system. The supply and demand monitoring device 10 evaluates the validity of a certain output allocation as to whether it is an optimal economic output allocation while satisfying stability constraints.

The supply and demand monitoring device 10 can access measurement information of the power system 20 via the communication network 300. The power system 20 here is illustrated as having the same configuration as that shown in FIG. 3, and is a system in which multiple regulated power sources G (GA to GD) and loads Ld (Ld1 to Ld6) are interconnected via nodes N (N1 to N6), transformers Tr (Tr1 to Tr4), and transmission lines L (L1 to L5). Various measuring instruments for protecting, controlling, and monitoring the power system 20 are installed at the nodes N (N1 to N6).

The supply and demand monitoring device 10 includes an output unit 21, an input unit 22, a communication unit 23, a processor 24, a memory 25, and a storage device 26, which are interconnected via a bus 27.

The display unit 21 displays the parameters handled by the supply and demand monitoring device 10 and the processing results of the supply and demand monitoring device 10. The display unit 21 may be a display device, or a printer device or an audio output device may be used together with the display device.

The input unit 22 inputs various conditions for operating the supply and demand monitoring device 10. The input unit 22 can use a keyboard and mouse, or it can be equipped with at least one of a touch panel or a voice instruction device.

The communication unit 23 includes a circuit and a communication protocol for connecting to the communication network 300. The communication network 300 may be a WAN (Wide Area Network) such as the Internet, a LAN (Local Area Network) such as Wi-Fi or Ethernet (registered trademark), or a mixture of WAN and LAN.

The processor 24 executes computer programs, searches for data in various databases stored in the storage device 26, issues instructions to display the processing results, and performs processing related to the supply and demand monitoring of the power system 20. The processor 24 may be a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit). The processor 24 may be a single-core processor or a multi-core processor. The processor 24 may be equipped with a hardware circuit (e.g., an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit)) that performs part or all of the processing. The processor 24 may be equipped with a neural network. The processor 24 may be configured as one or more semiconductor chips, or as a computer device such as a calculation server. Execution of the program may be shared among multiple processors or computers. Alternatively, the processor 24 may instruct a cloud computer or the like to execute all or part of the supply and demand monitoring program via the communication network 300 and receive the results of that execution.

The memory 25 is configured, for example, as a RAM (Random Access Memory) and stores computer programs and calculation result data, and provides the processor 24 with a work area required for each process.

The storage device 26 is a storage device with a large storage capacity, such as a hard disk drive or a solid state drive (SSD). The storage device 26 can hold executable files for various programs and data used to execute the programs. The storage device 26 can hold an output distribution command value model database DB1, a system information database DB2, and a stability result database DB3. The storage device 26 can also hold a supply and demand monitoring program. The supply and demand monitoring program may be software that can be installed in the supply and demand monitoring device 10, or may be incorporated in the supply and demand monitoring device 10 as firmware.

The output distribution command value database DB1 stores output distribution command values D1 that are distributed using a merit order method or the like. The system information database DB2 stores system information D2 for analyzing the stability of the power system. The stability result database DB3 stores stability results D3 related to various constraints such as overload, voltage deviation, voltage stability, and synchronous stability.

In FIG. 4, an example is shown in which the supply and demand monitoring device 10 stores an output distribution command value database DB1, a system information database DB2, and a stability result database DB3, but at least one of these databases may be stored in a cloud server.

Figure 5 is a block diagram showing an example of the functional configuration of the supply and demand monitoring device according to the first embodiment. In the following explanation, when the subject of an operation is described as "the XX unit", it means that the processor 24 in Figure 4 reads the XX unit, which is a program, and loads it into a DRAM (Dynamic Random Access Memory), which then realizes the function of the XX unit.

In FIG. 5, the supply and demand monitoring device 10 includes an output distribution command value database DB1, a system information database DB2, a stability result database DB3, an output distribution pattern determination unit 11, a system analysis unit 12, and a stability determination unit 13.

The output distribution pattern determination unit 11 inputs the output distribution command value D1 from the output distribution command value database DB1, determines a number of less expensive output distribution patterns, and outputs the results to the system analysis unit 12.

The system analysis unit 12 inputs an arbitrary time and an arbitrary output distribution command value D1, and also inputs system information D2 from a system information database DB2, and performs calculations such as power flow calculations, synchronous stability calculations, voltage stability calculations, and adjustment capacity reserve calculations, and outputs the results to the stability determination unit 13.

The stability determination unit 13 inputs the results calculated by the system analysis unit 12 and determines the stability of overload, voltage deviation, synchronous instability, voltage instability, and insufficient regulation power, and outputs the results to the stability result database DB3.

Figure 6 is a flowchart showing the processing of the supply and demand monitoring device of Figure 5. In Figure 6, first, in the output allocation pattern determination process in processing step S1, a number of less expensive output allocation patterns are determined based on the output allocation command value D1. The output allocation pattern may be determined manually or automatically, and is not limited to a specific determination method. Two examples of automatically determining the output allocation pattern are described below.

A first example of automatic output distribution pattern determination in processing step S1 will be described using the flow in FIG. 7 and the processing image in FIG. 8. A second example of automatic output distribution pattern determination in processing step S1 will be described using the flow in FIG. 9 and the processing image in FIG. 10.

As a first example of automatic output allocation pattern determination, an example is shown in which an output allocation pattern is determined while taking costs into consideration when the output allocation deviates from the ideal merit order in FIG. 1. FIG. 7 shows a flowchart illustrating an example of the processing of the output allocation pattern determination unit 11. Each processing step of the flowchart is explained using an image of the example of the processing of the output allocation pattern determination unit 11 in FIG. 8.

In the output allocation replacement target determination in processing step S11 in FIG. 7, an adjustable power source that deviates from the output allocation according to the ideal merit order is selected. In this case, the output allocation according to the ideal merit order is 30, 30, 20 output from the three units (GA, GB, GC) in FIG. 1 from the perspective of cost, so GB, GC, and GD are selected from among the adjustable power sources GA to GE as replacement targets for adjustable power sources that deviate from this relationship in the upper part of FIG. 8.

In the process step S12, the increase adjustment range is calculated. In the example in the upper part of Figure 8, when compared with the relationship in Figure 1, which is the output distribution according to the ideal merit order, it is the regulating power source GB whose output deviates to the lower side, and the increase adjustment range is +25.

Similarly, in the calculation of the downward adjustment range in processing step S13, the downward adjustment range is calculated. In the example in the upper part of Figure 8, when compared with the relationship in Figure 1, the output deviates to the upward side from the output distribution according to the ideal merit order for regulated power sources GC and GD, and the upward adjustment ranges are -5 and -20, respectively.

In the output replacement process in process step S14, the output is replaced within the range of the up-adjustment range and the down-adjustment range to find a candidate output allocation pattern that is less expensive. In the example in the middle of FIG. 8, as the first candidate output allocation pattern, the output is replaced in increments of 5 for the up-adjustment range and the down-adjustment range while taking into account costs, and as a result, the output of the regulating power source GB is changed from 5 to 10, and the output of the regulating power source GD is changed from 20 to 15. Therefore, the first output allocation pattern has the outputs of the regulating power sources GA to GE as 30, 10, 25, 15, and 0, respectively. In the output replacement process in process step S14, the process of replacing the output is continuously executed in increments of 5 for the up-adjustment range and the down-adjustment range while taking into account costs, and a new output allocation pattern is generated each time.

In processing step S15, it is determined whether output switching has been completed for the entire adjustment range. If it has been completed, this flow ends. If it has not been completed, the process returns to processing step S14, and the output allocation pattern for the next increment is determined. The output allocation pattern after completion is described in the lower part of Figure 8, and is the output allocation according to the ideal merit order illustrated in Figure 1.

As a second example of automatic output distribution pattern determination, we will explain an example of determining an output distribution pattern while taking costs into consideration when the output of a cheap regulated power source is smaller than the output of an expensive regulated power source, using the flow in Figure 9 and the processing image in Figure 10.

In the flowchart showing an example of the processing of the output distribution pattern determination unit in FIG. 9, first, in the output distribution transfer target determination process in processing step S21, when the output of the inexpensive regulated power source is smaller than the output of the expensive regulated power source, each regulated power source is selected. In the example in the upper part of FIG. 10, the output of the inexpensive regulated power source GB is 5, which is even smaller than the output of the expensive regulated power source GD, which is 20, and regulated power sources GB and GD are selected as the initial output distribution transfer targets. Note that, as will be clear from the following processing, in the example of FIG. 10, GB, GC, and GD are ultimately selected as the transfer targets from among the regulated power sources GA to GE.

In the process step S22 of selecting an inexpensive regulated power source, the least expensive regulated power source is selected from among the replacement targets. In the example in the upper part of FIG. 10, regulated power source GB is selected. In the process step S23 of selecting an expensive regulated power source, in the example in the upper part of FIG. 10, the most expensive regulated power source GD is selected from among the replacement targets.

In the output switching process of processing step S24, the outputs of both regulated power sources GB and GD are switched until the outputs become the same, thereby finding candidates for a cheaper output distribution pattern. In the example in the upper part of FIG. 10, the first candidate output distribution pattern shows that the output of the regulated power source GB is changed from 5 to 12.5, and the output of the regulated power source GD is changed from 20 to 12.5 as a result of switching the outputs of both regulated power sources GB and GD while taking into account costs. At this time, the outputs may be switched while taking into account certain increments.

In processing step S25, it is determined whether output switching has been completed for all regulated power sources. If it has been completed, the flow ends. If it has not been completed, the flow returns to processing step S22, and the output allocation pattern for the next increment is determined.

The middle part of Figure 10 shows that after the first switching process for both regulated power sources GB and GD, a case is considered in which the output of the cheaper regulated power source is smaller than the output of the more expensive regulated power source again, and as a result, in the second switching process, an adjustment range of 6.25 is used between the regulated power sources GB and GC. In this case as well, a new output distribution pattern is generated each time a switching process is performed.

As a result, as shown in the lower part of Figure 10, the outputs of both regulated power supplies GB and GD become equal, and the next execution condition, "when the output of the inexpensive regulated power supply is smaller than the output of the expensive regulated power supply," no longer exists, indicating that processing has ended.

Returning to FIG. 6, the system analysis unit 12 in processing step S2 performs system analysis such as power flow calculation, synchronous stability calculation, voltage stability calculation, and adjustment reserve calculation. For the system analysis, multiple stability calculations may be performed, or only one stability calculation may be performed.

The stability determination unit 13 in processing step S3 outputs data on the output allocation pattern and stability results for the system analysis results such as power flow calculation, synchronous stability calculation, voltage stability calculation, and adjustment capacity reserve calculation. Stability includes overload, voltage deviation, synchronous stability, voltage stability, and insufficient adjustment capacity, as described in the background art.

Processing steps S2 and S3 are performed for each output distribution pattern in the intermediate stages (middle stage of FIG. 8, middle stage of FIG. 10) from the initial stage (upper stage of FIG. 8, upper stage of FIG. 10) in processing step S1 to the final stage (lower stage of FIG. 8, lower stage of FIG. 10), and various stability evaluations are performed for multiple output distribution patterns.

Figure 11 shows an example of an output image of the output allocation patterns of regulated power sources and the results of stability analysis. Here, the output of each regulated power source from the initial stage 1 through the intermediate stage to the final stage X as an output allocation pattern, the cost for the output allocation pattern at each stage, and the results of various stability judgments are organized in a list. This list makes it clear at what timing and in what situation instability will occur if the operation of the regulated power sources of the power system is changed chronologically from the initial stage 1 through the intermediate stage to the final stage X. From this, when past output allocations at any time are all stable at each stability and any output allocation command value is unstable at one or more stability levels, it can be said that the output allocation command value is the most economical output allocation while satisfying the stability constraints.

As described above, according to the above-mentioned Example 1, it is possible to evaluate the validity of the output allocation as to whether it is the most economical output allocation while satisfying the stability constraint.

Figure 12 is a block diagram showing the functional configuration of a supply and demand monitoring device according to the second embodiment.

The supply and demand monitoring device 10 in FIG. 12 is an embodiment 1 including an output distribution command value database DB1, a system information database DB2, a stability result database DB3, an arbitrary output distribution command value database DB4, an output distribution pattern determination unit 11, a system analysis unit 12, a stability assessment unit 13, an output distribution determination unit 14, and an output reallocation determination unit 15, and is further equipped with an arbitrary output distribution command value database DB4 in addition to the supply and demand monitoring device 10 in FIG. 5.

The arbitrary power distribution command value database DB4 stores one or more patterns of arbitrary power distribution command values.

The output distribution pattern determination unit 11 inputs the output distribution command value and the arbitrary output distribution command value, determines multiple cheaper output distribution patterns, and outputs the results to the system analysis unit 12.

The system analysis unit 12 inputs the output allocation pattern calculated by the output allocation pattern determination unit 11 and the system information stored in the system information DB 2, and performs calculations such as power flow calculations, synchronous stability calculations, voltage stability calculations, and adjustment capacity reserve calculations, and outputs the results to the stability determination unit 13.

The stability determination unit 13 inputs the results calculated by the system analysis unit 12 and determines the stability of overload, voltage deviation, synchronous instability, voltage instability, and insufficient regulation power, and outputs the results to the stability result database DB3.

Figure 13 is a flowchart showing the processing of the supply and demand monitoring device in Figure 12.

In the output distribution pattern determination process S1, the output distribution pattern is determined based on one or both of the output distribution command values obtained by output distribution using a merit order method or the like and the arbitrary output distribution command values. Two examples of the output distribution patterns input to the system analysis unit 12 are described below.

In the first example, an arbitrary output distribution command value is used from the arbitrary output distribution command value database DB4. By using an arbitrary output distribution command value desired by a system operator or power generation company (such as an output distribution command value that is cheaper than the output distribution command value allocated using the merit order method, etc.) as the input value, the stability of the desired output distribution command value can be determined.

In the second example, the output allocation pattern is an output allocation command value allocated using the merit order method or the like, and an arbitrary output allocation command value from the arbitrary output allocation command value database DB4. By using the output allocation command value allocated using the merit order method or the like as an input value in addition to an arbitrary output allocation command value desired by the system operator or power generation company (such as an output allocation command value that is cheaper than the output allocation command value allocated using the merit order method or the like), it is possible to determine not only the stability of the desired output allocation command value, but also the stability of the output allocation command value allocated using the merit order method or the like. This makes it possible to confirm the difference in the stability results between the two.

In processing step S2, the system analysis unit 12 performs system analysis such as power flow calculation, synchronous stability calculation, voltage stability calculation, and adjustment reserve calculation. For the system analysis, multiple stability calculations may be performed, or only one stability calculation may be performed.

The stability determination unit 13 in processing step S3 outputs data on the output allocation pattern and stability results for the system analysis results such as power flow calculation, synchronous stability calculation, voltage stability calculation, and adjustment capacity reserve calculation. Stability includes overload, voltage deviation, synchronous stability, voltage stability, and insufficient adjustment capacity, as described in the background art.

Figure 14 shows an example of the output image of the output allocation pattern of the regulating power source and the results of stability analysis. When all past output allocations at any time are stable at each stability level, and any output allocation command value is unstable at one or more stability levels, it can be said that the output allocation command value is the most economical output allocation while satisfying the stability constraints.

As described above, according to the second embodiment, it is possible to evaluate the validity of the output allocation as to whether it is the most economical output allocation while satisfying the stability constraints.

Figure 15 is a block diagram showing the functional configuration of a supply and demand monitoring device according to the third embodiment.

In FIG. 15, the supply and demand adjustment device 10 includes an output allocation command value database DB1, a system information database DB2, a stability result database DB3, an output reallocation command value database DB5, an output allocation pattern determination unit 11, a system analysis unit 12, a stability assessment unit 13, an output allocation determination unit 14, and an output reallocation determination unit 15, in addition to the supply and demand monitoring device 10 of Example 1 and FIG. 5, which further includes an output reallocation command value DB4, an output allocation determination unit 14, and an output reallocation determination unit 15.

The power reallocation command value database DB5 stores power reallocation command values that reduce costs while still achieving stability based on power allocation command values allocated using the merit order method or other methods.

The output distribution determination unit 14 inputs the supply and demand imbalance, determines the output distribution to each regulating power source, and outputs the result to the output distribution command value database DB1.

The output allocation pattern determination unit 11 inputs the output allocation command value calculated by the output allocation determination unit 14, determines multiple cheaper output allocation patterns, and outputs the results to the system analysis unit 12.

The system analysis unit 12 inputs the output allocation pattern calculated by the output allocation pattern determination unit 11 and the system information stored in the system information DB 2, and performs calculations such as power flow calculations, synchronous stability calculations, voltage stability calculations, and adjustment capacity reserve calculations, and outputs the results to the stability determination unit 13.

The stability determination unit 13 inputs the results calculated by the system analysis unit 12 and determines the stability of overload, voltage deviation, synchronous instability, voltage instability, and insufficient adjustment power, and outputs the results to the stability result database DB3 and the output reallocation determination unit 15.

The output reallocation determination unit 15 inputs multiple output allocation patterns and their stability results, selects the most economical output reallocation command value while satisfying the stability constraints, and outputs the result to the output reallocation command value database DB5.

Figure 16 is a flowchart showing the processing of the supply and demand adjustment device in Figure 15.

In the first processing step S34, output allocation determination, the output allocation to each regulating power source is determined based on the amount of supply and demand imbalance. For example, output allocation according to merit order is determined. When determining the output allocation of each regulating power source according to merit order, in the direction of increasing regulating power, regulating power can be allocated from each regulating power source with the lowest cost within the constraints that can be allocated to each regulating power source. In the direction of decreasing regulating power, regulating power can be allocated from each regulating power source with the highest cost within the constraints that can be allocated to each regulating power source. The cost referred to here may include the fuel cost of the regulating power source as well as the procurement cost.

At this time, in order to operate the power system stably, it is necessary to determine output allocation so as to satisfy not only the supply and demand balance but also the power system stability such as overload, voltage deviation, voltage stability, and synchronous stability. For this purpose, it is common to determine output allocation by optimization calculation after setting various constraints.

In the output allocation pattern determination in processing step S31, multiple cheaper output allocation patterns are determined based on the output allocation determined in processing step S34. Two examples of determining the output allocation pattern are described below.

In processing step S32, the system analysis unit 12 performs system analysis such as power flow calculation, synchronous stability calculation, voltage stability calculation, and adjustment reserve calculation. For the system analysis, multiple stability calculations may be performed, or only one stability calculation may be performed.

The stability determination unit 13 in processing step S33 outputs data on the output distribution pattern and stability results for the system analysis results such as power flow calculation, synchronous stability calculation, voltage stability calculation, and adjustment capacity reserve calculation. Stability includes overload, voltage deviation, synchronous stability, voltage stability, and insufficient adjustment capacity, as explained in the background art. Figure 17 shows an example of an output image of the output distribution pattern of the regulating power source and the results of stability analysis.

In the output allocation re-determination in processing step S35, the presence or absence of constraint violations is determined by stability analysis of multiple output allocation patterns. If one or more of all output allocation patterns are unstable in each stability, the output allocation command value determined by the output allocation determination unit 14 can be said to be the most economical output allocation in which the output allocation satisfies the stability constraints. Furthermore, if there are output allocation patterns that are all stable in each stability, the output allocation pattern with the lowest cost among the relevant output allocation patterns is selected as the output reallocation command value. In the example of Figure 17, assuming that only pattern 1 and pattern 2 are stable in all stabilities among patterns 1 to X, pattern 2, which is the cheaper pattern, is selected.

The above explanation has been mainly about configuring a power system supply and demand monitoring device, but it goes without saying that a supply and demand adjustment device can be configured by further providing a function for allocating the output distribution pattern defined here to an adjustment power source.

As explained above, according to the above-mentioned third embodiment, it is possible to search for an even better power distribution and perform power distribution based on that, thereby reducing costs while still satisfying stability.

The present invention is not limited to the above-described embodiments, and includes various modified examples. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those having all of the configurations described. It is also possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to add, delete, or replace part of the configuration of each embodiment with other configurations. Furthermore, the above-described configurations, functions, processing units, etc. may be realized in part or in whole in hardware, for example by designing them as integrated circuits.

DB1: Power distribution command value database DB2: System information database DB3: Stability result database DB4: Optional power distribution command value database DB5: Power reallocation command value database 20: Power system 10: Supply and demand monitoring device 11: Output distribution pattern determination unit 12: System analysis unit 13: Stability judgment unit 14: Output distribution determination unit 15: Output reallocation determination unit 21: Display unit 22: Input unit 23: Communication unit 24: Processor 25: Memory 26: Storage device 27: Bus 300: Communication network

Claims (12)

A supply and demand monitoring device that determines an output allocation pattern of a plurality of regulating power sources in a power system,
1. A supply and demand monitoring device comprising: an output allocation pattern determination unit that determines a plurality of output allocation patterns including the output and cost of each regulated power source at each stage in an output transfer process from an initial stage through an intermediate stage to a final stage that is cheaper than an output allocation command value; a system analysis unit that performs a system analysis of the power system based on each of the output allocation patterns at each stage from the output allocation pattern determination unit; and a stability determination unit that determines the stability of the power system at the time of the output allocation pattern at each stage as a result of the system analysis by the system analysis unit, wherein the most economical output allocation is obtained as the output allocation pattern at each stage of the plurality of regulated power sources in the power system while satisfying the stability constraints of the power system. 2. The supply and demand monitoring device according to claim 1,
A supply and demand monitoring device characterized in that at least one of a power flow calculation, a synchronous stability calculation, a voltage stability calculation, and a guaranteed adjustment capability calculation is calculated by the system analysis in the system analysis unit. The supply and demand monitoring device according to claim 1 or 2,
The supply and demand monitoring device is characterized in that the stability determination unit determines stability with respect to at least one of overload, voltage deviation, synchronization instability, voltage instability, and insufficient regulation capability. The supply and demand monitoring device according to any one of claims 1 to 3,
The output allocation pattern determination unit determines the output allocation by an adjustable power source selected from among a plurality of adjustable power sources from the viewpoint of cost as an output allocation according to an ideal merit order, and in the event of a deviation from the output allocation according to the ideal merit order, determines an output allocation pattern while taking costs into consideration, including adjustable power sources that are not included in the ideal merit order. The supply and demand monitoring device according to any one of claims 1 to 4,
A supply and demand monitoring device characterized in that the output distribution pattern determination unit determines the output distribution pattern while taking cost into consideration when the output of an inexpensive regulating power source is smaller than the output of an expensive regulating power source. The supply and demand monitoring device according to any one of claims 1 to 5,
The supply and demand monitoring device is characterized in that the output allocation pattern determination unit determines an output allocation pattern based on either one or both of an output allocation command value allocated by a merit order method and an arbitrary output allocation command value. The supply and demand monitoring device according to any one of claims 1 to 6,
A supply and demand monitoring device characterized in that it is further provided with an output reallocation determination unit that determines an output reallocation command value based on multiple output allocation patterns and their stability results, thereby being able to apply a cheaper output allocation pattern while satisfying the stability constraints. The supply and demand monitoring device according to claim 7,
A supply and demand monitoring device comprising an output allocation determination unit that inputs a supply and demand imbalance and determines an output allocation to each regulating power source, the result of the output allocation determination unit being output to the output allocation pattern determination unit, and the output allocation pattern determination unit determining a plurality of less expensive output allocation patterns. The supply and demand monitoring device according to claim 7,
The output reallocation determination unit is a supply and demand monitoring device that receives a plurality of output allocation patterns and their stability results as input, selects the most economical output reallocation command value while satisfying the stability constraints, and outputs the result to the output reallocation command value database. A supply and demand adjustment device comprising the supply and demand monitoring device according to any one of claims 1 to 9, and configured to give output commands to a plurality of regulated power sources in a power system via communication means,
A supply and demand adjustment device characterized in that the output means selects one output allocation pattern which is the most economical output allocation while satisfying the stability constraints of the power system, and issues output commands to a plurality of regulating power sources via a communication means. A supply and demand monitoring method for determining an output allocation pattern of a plurality of regulating power sources in a power system using a computer, comprising:
A supply and demand monitoring method characterized in that a computer determines a plurality of output allocation patterns including the output and cost of each regulating power source at each stage in the output transfer process from the initial stage through the intermediate stage to the final stage that is cheaper than an output allocation command value, performs a system analysis of the power system based on each of the output allocation patterns at each stage, determines the stability of the power system for the output allocation pattern at each stage as a result of the system analysis, and obtains the most economical output allocation while satisfying the constraints of the stability of the power system as the output allocation pattern at each stage of the plurality of regulating power sources in the power system. A supply and demand adjustment method in which an output allocation pattern obtained by the supply and demand monitoring method according to claim 11 is given as an output command to a plurality of regulating power sources in a power system,
A supply and demand adjustment method comprising the steps of: selecting one output allocation pattern which is the most economical output allocation while satisfying the stability constraints of the power system; and providing this as an output command to a plurality of adjustment power sources.

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