Fuel cell systems and methods for controlling fuel cell systems.

Abstract

This electric power distribution system managing device (1) is equipped with: a communication unit (16) that receives measurement values from each of a plurality of high-voltage sensors for measuring the voltage and power flow on the electric power distribution lines of a high-voltage system, and receives the amount of electric power from a plurality of smart meters for measuring the amount of electric power; and a voltage control unit that divides the electric power distribution line between two high-voltage sensors from among the plurality of high-voltage sensors into a plurality of segments, and estimates the voltage distribution on the electric power distribution line on the basis of two measurement values received from the two high-voltage sensors and the amount of electric power per segment.

Description

Power distribution system status estimation device and power distribution system status estimation method The present invention relates to a power distribution system state estimation device and a power distribution system state estimation method for estimating the state of a high-voltage power distribution system. A power distribution system generally consists of a high-voltage system and a low-voltage system, and the receiving end of a typical consumer's power supply is connected to the low-voltage system. Power companies are obligated to maintain the voltage at the receiving end of a typical consumer's power supply within an appropriate voltage range. For example, in the case of a 100V power supply, the voltage must be maintained between 95V and 107V. Therefore, power companies maintain the voltage at the receiving end of a typical consumer's power supply by adjusting the control amount of the voltage control equipment connected to the high-voltage system. In the following, unless otherwise specified, "power distribution system" refers to the high-voltage system. For controlling voltage control equipment connected to the power distribution system, and for planning the equipment of the power distribution system, it is important to estimate the state of the power distribution system, that is, the voltage at each point in the power distribution lines of the power distribution system. Nowadays, various solar power generation systems of all sizes, including residential solar power generation facilities and mega solar power plants, are being connected to the power distribution system, and the state of the power distribution system fluctuates due to fluctuations in the amount of power generated by these solar power generation systems. Patent Document 1 discloses a technique for calculating the state of a power distribution system, i.e., the voltage distribution, in order to plan the arrangement of a switch with a built-in sensor. Japanese Patent Publication No. 2015-109728 However, the technology described in Patent Document 1 above calculates the voltage distribution using pre-stored power system data and power state data. As a result, there is a problem in that the difference between the actual voltage distribution and the estimated voltage distribution, i.e., the estimation error of the state of the power distribution system, becomes large. The present invention has been made in view of the above, and aims to provide a power distribution system state estimation device that can estimate the state of a power distribution system with high accuracy. To solve the above-mentioned problems and achieve the objective, the power distribution system state estimation device according to the present invention includes a communication unit that receives measured values ​​from a plurality of high-voltage sensors that measure the voltage and power flow of power distribution lines in a high-voltage system, and receives power from a plurality of smart meters that measure power. Furthermore, the power distribution system state estimation device according to the present invention includes a state estimation unit that divides the power distribution line between two of the plurality of high-voltage sensors into a plurality of sections, and estimates the voltage distribution in the power distribution line based on two measured values ​​received from the two high-voltage sensors and the power amount for each section. This invention has the effect of enabling accurate estimation of solar power generation while suppressing the increase in measurement and communication equipment. Figure showing an example of a power distribution system according to the embodiment. Figure showing an example of the configuration of a power distribution system management device according to the embodiment. Figure showing an example of the configuration of a meter data management device according to the embodiment. Figure showing an example of the configuration of a computer system according to the embodiment. Figure showing an example of the configuration of a smart meter according to the embodiment. Flowchart showing an example of the calculation procedure for past power generation and load amounts in a power distribution system management device. Figure showing an example of the configuration of measurement data transmitted by a smart meter. Figure showing an example of the configuration of load contract data. Figure showing an example of the configuration of solar power generation equipment data. Figure showing active power and reactive power distributed to each section in a power distribution line. Figure showing an example of virtual load arrangement. Flowchart showing an example of the state estimation and voltage control procedure according to the embodiment. Embodiments of the power distribution system state estimation device and power distribution system state estimation method according to the present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to these embodiments. Embodiment 1. Figure 1 shows an example of a power distribution system according to Embodiment 1 of the present invention. In Figure 1, the voltage control device 7 is, for example, an LRT (Load Ratio control Transformer) installed in a substation as a power distribution transformer. A busbar 8 is connected to the secondary side of the voltage control device 7. Two power distribution lines 9-1 and 9-2 are connected in parallel to the busbar 8. Power distribution lines 9-1 and 9-2 are power distribution lines for the high-voltage system. Although Figure 1 shows an example in which two power distribution lines are connected, the number of power distribution lines connected to the busbar 8 is not limited to two. Distribution line 9-1 is connected to busbar 8 at one end via circuit breaker 6-1. A high-voltage sensor 5-1, which measures the voltage and power flow of distribution line 9-1, is installed at the upstream end of distribution line 9-1. A high-voltage sensor 5-3, which measures the voltage and power flow at the end of distribution line 9-1, is connected to the end of distribution line 9-1. Distribution line 9-2 is connected to busbar 8 at one end via circuit breaker 6-2. A high-voltage sensor 5-2, which measures the voltage and power flow of distribution line 9-2, is installed at the upstream end of distribution line 9-2. A high-voltage sensor 5-4, which measures the voltage and power flow at the end of distribution line 9-2, is connected to the end of distribution line 9-2. The circuit breaker 6-1 and the high-voltage sensor 5-1 may be integrated into one unit, and the circuit breaker 6-2 and the high-voltage sensor 5-2 may be integrated into one unit. High-voltage sensors 5-1 to 5-4 measure voltage and power flow, for example, at regular intervals, and transmit the average value of the measured results over a certain period as measurement information. Any values ​​can be used for the measurement period and the regular time used to calculate the average value for high-voltage sensors 5-1 to 5-4, but for example, the measurement period is set to 1 second and the regular time used to calculate the average value is set to 1 minute. High-voltage sensors 5-1 to 5-4 have a communication function and are connected to the communication network 2. High-voltage sensors 5-1 to 5-4 periodically transmit measurement information to the power distribution system management device 1 via the communication network 2. Alternatively, high-voltage sensors 5-1 to 5-4 may transmit measurement information only when they receive an instruction from the power distribution system management device 1 requesting the transmission of measurement information, rather than transmitting measurement information periodically. Distribution line 9-1 is connected to loads 3-1 to 3-3 and solar power generation equipment 4-1 and 4-2. Loads 3-1, 3-2, and 3-3 each represent loads for individual consumers. Load 3-1 is the load of consumer 30-1, load 3-2 is the load of consumer 30-2, and load 3-3 is the load of consumer 30-3. Note that Figure 1 shows only some of the loads and solar power generation equipment connected to distribution line 9-1, and other loads and solar power generation equipment not shown in Figure 1 are also connected to distribution line 9-1. Also, for the sake of simplification, loads and solar power generation equipment connected to distribution line 9-2 are omitted in Figure 1, but loads and solar power generation equipment are also connected to distribution line 9-2. As shown in Figure 1, customer 30-1 owns a solar power generation facility 4-1, and customer 30-2 owns a solar power generation facility 4-2. Customer 30-3 does not own a solar power generation facility. Customer 30-1 has a full purchase agreement with the electric utility company to sell all the electricity generated by the solar power generation facility 4-1. In other words, the solar power generation facility 4-1 is a power generation facility subject to the full purchase agreement. Customer 30-2 has a surplus purchase agreement with the electric utility company to sell the surplus electricity obtained by subtracting the amount of electricity consumed by load 3-2 from the amount of electricity generated by the solar power generation facility 4-2. Smart meters 31-1, 31-2, 32, and 33 are electricity meters for automatic meter reading and have communication functions. In the diagram, smart meters are abbreviated as SM (Smart Meter). Smart meter 32 is connected to the solar power generation facility 4-1 of customer 30-1, who has a full purchase agreement, to measure the amount of electricity generated by the solar power generation facility 4-1. Smart meter 31-1 is also connected to load 3-1 of customer 30-1. Smart meter 33 is connected to load 3-2 and solar power generation facility 4-2 of customer 30-2, who has a surplus purchase agreement. Smart meter 31-2 is connected to load 3-3 of customer 30-3. Smart meters 31-1 and 31-2 measure the amount of electricity in the downstream direction, that is, from the electricity company to the customer. Smart meter 32 measures the amount of electricity in the upstream direction, that is, from the customer to the electricity company. The smart meter 33 measures the amount of electricity obtained by subtracting the amount of electricity in the downstream direction from the amount of electricity in the upstream direction. When smart meters 31-1 and 31-2 are not distinguished, they are also referred to as smart meter 31. Smart meters 31-1, 31-2, 32, and 33 are connected to a meter data management device 20 via a communication network 21. Smart meters 31-1, 31-2, 32, and 33 measure the amount of electricity at a fixed measurement cycle and transmit the measured amount of electricity to the meter data management device 20. In other words, the communication network 21 is a communication network for sending and receiving measurement data measured by smart meters. In this embodiment, the measurement cycle, or data collection cycle, of smart meters 31-1, 31-2, 32, and 33 is set to 30 minutes. However, the measurement cycle of smart meters 31-1, 31-2, 32, and 33 is not limited to 30 minutes. Figure 1 shows smart meters 31-1, 31-2, 32, and 33 as examples, but other smart meters besides smart meters 31-1, 31-2, 32, and 33 are also connected to the power distribution lines 9-1 and 9-2 shown in Figure 1. Hereafter, smart meters used to measure the power generation of solar power generation facilities of customers with whom a full purchase agreement has been concluded will be referred to as full purchase smart meters. Smart meter 32 in Figure 1 is a full purchase smart meter. The power distribution system management device 1, which is a power distribution system status estimation device, estimates the state of the power distribution lines 9-1 and 9-2 of the power distribution system, i.e., the voltage distribution of the power distribution lines 9-1 and 9-2, by correcting the measured values ​​of the high-voltage sensor with the measured values ​​of the smart meter. Furthermore, the power distribution system management device 1 controls the voltage control equipment connected to the power distribution lines 9-1 and 9-2 based on the estimation results of the state of the power distribution lines 9-1 and 9-2 of the power distribution system. The power distribution system management device 1 can be installed in a business office or control center that has jurisdiction over the power distribution system to be managed. The voltage control device 7 is connected to a voltage control device 80 that controls the voltage control device 7. The power distribution system management device 1 transmits information to the voltage control device 80 via the communication network 2 as a voltage control amount, for example, information indicating the upper and lower limits of the voltage control range. The voltage control device 80 controls the voltage control device 7 based on the information received from the power distribution system management device 1. Multiple voltage control devices (not shown) are connected to the power distribution lines 9-1 and 9-2, and each of these voltage control devices is controlled by a voltage control device. At least some of these voltage control devices may perform control based on the voltage control amount received from the power distribution system management device 1 via the communication network 2, similar to the voltage control device 80. Thus, in this embodiment, the explanation is based on the premise of a centralized voltage control system in which the power distribution system management device 1 controls the voltage of the power distribution system. Here, an example is described in which the power distribution system management device 1 also functions as a centralized voltage control device that performs centralized voltage control, but a separate centralized voltage control device may be provided in addition to the power distribution system management device 1. Furthermore, measuring devices 53-1 and 53-2 for measuring solar radiation are connected to the communication network 21. Hereafter, when measuring devices 53-1 and 53-2 are not distinguished, they will be referred to as measuring device 53. Figure 1 shows two measuring devices, but in reality, multiple measuring devices 53 can be geographically dispersed; for example, one can be installed approximately every 1 km square. It is desirable that measuring devices 53 be installed in locations where there is little shade, for example, on the north side of a road, on the roof of a building, on the roof of a house, on a utility pole, or on a relay tower of a mobile communication system such as a cell phone network. The installation locations of measuring devices 53 are not limited to these. In this embodiment, an example in which measuring devices 53 are installed is described, but measuring devices 53 do not necessarily have to be installed. Furthermore, the following description explains an example in which the measured values ​​from the measuring device 53 are transmitted from the meter data management device 20 to the power distribution system management device 1 together with the measured values ​​from the smart meter 31. However, the measured values ​​from the measuring device 53 may be transmitted to the power distribution system management device 1 separately from the measured values ​​from the smart meter 31. The measured values ​​from the measuring device 53 may be transmitted to the power distribution system management device 1 via a dedicated network for the pyranometer, or via the communication network 2. The measuring device 53 may also transmit the measured values ​​to the power distribution system management device 1 in near real-time, with a cycle shorter than the 30-minute data collection cycle of the smart meter 31, for example, a 1-minute cycle. The measuring device 53 includes a communication unit 51 that performs communication processing for connecting to the communication network 21, and a pyranometer 52 that measures solar radiation. The communication unit 51 transmits the measured values, i.e., measurement data, measured by the pyranometer 52 to the meter data management device 20 via the communication network 21. The communication unit 51 can be shared with the communication units in the smart meters 31-1, 31-2, 32, and 33 described later. Figure 2 shows an example of the configuration of the power distribution system management device 1 according to this embodiment. The power distribution system management device 1 includes a power generation amount estimation unit 11, a load estimation unit 12, a load calculation unit 13, a power generation amount calculation unit 14, a voltage control unit 15, a communication unit 16, and a storage unit 17. The power generation estimation unit 11 estimates the past power generation amount for each solar power generation facility in the distribution system using past measurements from smart meters that purchase all electricity and measurements from a pyranometer, i.e., measuring device 53. If a pyranometer, i.e., measuring device 53 is not installed, the power generation amount for each solar power generation facility in the distribution system is estimated using past measurements from smart meters that purchase all electricity. Furthermore, the power generation estimation unit 11 estimates the power generation amount for each section based on the past power generation amount for each solar power generation facility, as will be described later. Here, as will be described later, it is assumed that the distribution system management device 1 acquires the measurements from smart meters that purchase all electricity and measurements from measuring device 53 on a daily basis via the communication network 21 and the meter data management device 20. For this reason, it is assumed that the measurements from smart meters that purchase all electricity and measurements from measuring device 53 are from the past, i.e., the previous day. However, the distribution system management device 1 may be configured to acquire the measurements from smart meters that purchase all electricity and measurements from measuring device 53 in near real time. The load estimation unit 12 calculates the total past load based on past measurements from high-voltage sensors 5-1 to 5-4, past power generation, and SM measurement data, and stores it in the storage unit 17 as load data. At this time, the load data may be stored in association with at least one of the following: temperature, time, and day of the week. By storing the load data in association with at least one of the following: temperature, time, and day of the week, it becomes possible to estimate the load according to the temperature, time, day of the week, etc., when estimating the current or future load using past load data. The load calculation unit 13 calculates the current load amount for each section based on the load data. Specifically, the load calculation unit 13 calculates the load amount based on past measurements from high-voltage sensors 5-1 to 5-4 and past measurements from smart meters. The power generation amount calculation unit 14 determines the current total power generation amount based on the load amount for each section and the current power flow measurements from high-voltage sensors 5-1 to 5-4, and calculates the power generation amount for each section based on the total power generation amount. Specifically, the power generation amount calculation unit 14 calculates the load amount based on past measurements from high-voltage sensors 5-1 to 5-4 and past measurements from smart meters. The voltage control unit 15 calculates the voltage distribution based on the load amount calculated by the load calculation unit 13 and the power generation amount calculated by the power generation amount calculation unit 14, and determines the control amount for the voltage control equipment based on the voltage distribution. The communication unit 16 receives the measured values ​​from high-voltage sensors 5-1 to 5-4 via the communication network 2. The communication unit 16 also transmits information indicating the voltage control amount calculated by the voltage control unit 15 to the voltage control device 80, or to the voltage control device 80 and other voltage control devices. The communication unit 16 stores the received measured values ​​from high-voltage sensors 5-1 to 5-4 as sensor measurement data in the storage unit 17. The communication unit 16 also communicates with the meter data management device 20. The communication unit 16 stores the solar radiation measurement data and SM measurement data received from the meter data management device 20 in the storage unit 17. In this embodiment, the power distribution system management device 1 stores load contract data and solar power generation equipment data as equipment data in the storage unit 17. Furthermore, if a measuring device 53 is installed, the storage unit 17 also stores pyranometer position data. Figure 3 shows an example of the configuration of the meter data management device 20. The meter data management device 20 comprises an SM management unit 22, a data management unit 23, a storage unit 24, and a communication unit 25. The communication unit 25 communicates with smart meters and measuring devices 53 via a communication network 21. The communication unit 25 also communicates with the power distribution system management device 1 and the charge management device 40. The charge management device 40 is a device that processes electricity buying and selling, including creating invoices showing electricity charges that the electric utility company bills each customer, and creating notifications of the amount of electricity purchased by the electric utility company from each customer. The meter data management device 20 is a management device called an MDMS (Meter Data Management System) that receives measurement data, i.e., automatic meter reading data, which is the measured value of electricity consumption, from smart meters 31-1, 31-2, 32, and 33, and stores the received measurement data, i.e., SM measurement data, in the storage unit 24. Furthermore, the meter data management device 20 stores measurement data received from the measuring device 53, i.e., solar radiation measurement data, which is the measurement data measured by the pyranometer 52, in the storage unit 24. In addition, the meter data management device 20 controls the starting and stopping of smart meters 31-1, 31-2, 32, and 33. The meter data management device 20 may also control the starting and stopping of the measuring device 53. The SM management unit 22 controls the starting and stopping of the smart meter. The SM management unit 22 may also control the starting and stopping of the measuring device 53. The data management unit 23 manages the SM measurement data received from the smart meter. The data management unit 23 transmits the SM measurement data, which is the measurement data of the smart meter stored in the storage unit 24, to the charge management device 40 and the power distribution system management device 1 via the communication unit 25. The data management unit 23 also transmits the solar radiation measurement data, which is the measurement data of the measuring device 53 stored in the storage unit 24, to the power distribution system management device 1 via the communication unit 25. The power distribution system management device 1 is specifically a computer system. The computer system functions as the power distribution system management device 1 when a power distribution system management program is executed on this computer system. Figure 4 shows an example of the configuration of the computer system in this embodiment. As shown in Figure 4, this computer system comprises a control unit 101, an input unit 102, a storage unit 103, a display unit 104, a communication unit 105, and an output unit 106, which are connected via a system bus 107. In Figure 4, the control unit 101 is, for example, a CPU (Central Processing Unit) and executes the power distribution system management program of this embodiment. The input unit 102 is, for example, a keyboard and mouse and is used by the user of the computer system to input various information. The storage unit 103 includes various types of memory such as RAM (Random Access Memory) and ROM (Read Only Memory), and storage devices such as a hard disk and stores the program to be executed by the control unit 101, necessary data obtained during the processing, etc. The storage unit 103 is also used as a temporary storage area for the program. The display unit 104 is, for example, an LCD (Liquid Crystal Display Panel) and displays various screens to the user of the computer system. The communication unit 105 performs communication processing. Note that Figure 4 is just one example, and the configuration of the computer system is not limited to the example in Figure 4. Here, an example of the operation of the computer system until the power distribution system management program of this embodiment becomes executable will be described. In the computer system with the above configuration, for example, the power distribution system management program is installed in the storage unit 103 from a CD-ROM or DVD-ROM set in a CD (Compact Disc)-ROM or DVD (Digital Versatile Disc)-ROM drive (not shown). When the power distribution system management program is executed, the power distribution system management program read from the storage unit 103 is stored in a predetermined location in the storage unit 103. In this state, the control unit 101 executes the power distribution system management process of this embodiment according to the program stored in the storage unit 103. In this embodiment, a program describing power distribution system management processing is provided on a CD-ROM or DVD-ROM as the recording medium. However, the system is not limited to this, and depending on the configuration of the computer system, the capacity of the program to be provided, a program provided via a transmission medium such as the Internet via the communication unit 105 may be used. The power generation estimation unit 11, load estimation unit 12, load calculation unit 13, power generation calculation unit 14, and voltage control unit 15 shown in Figure 2 are included in the control unit 101 in Figure 4. The storage unit 17 in Figure 2 is part of the storage unit 103 in Figure 4. The communication unit 16 in Figure 2 corresponds to the communication unit 105 in Figure 4. The meter data management device 20, like the power distribution system management device 1, is specifically a computer system. When the meter data management device 20 is implemented in the computer system shown in Figure 4, the SM management unit 22 and data management unit 23 in Figure 3 are included in the control unit 101 in Figure 4. The storage unit 24 in Figure 3 is part of the storage unit 103 in Figure 4, and the communication unit 25 in Figure 3 corresponds to the communication unit 105 in Figure 4. An example of the operation of the computer system until the meter data management program, which is the program for realizing the meter data management device 20 of this embodiment, becomes executable is the same as the example of the operation of the computer system until the power distribution system management program becomes executable. Figure 5 shows an example of the configuration of the smart meter 31 of this embodiment. The smart meter 31 includes a communication unit 51 that performs communication processing for connecting to a communication network 21, and an energy meter 34 that measures the amount of electricity. Smart meters 32 and 33 have the same configuration as smart meter 31. However, the electricity meter 34 of smart meter 32 measures the amount of electricity in the upstream direction, that is, the direction from the consumer to the electric utility company. Also, the electricity meter 34 of smart meter 33 measures the amount of electricity obtained by subtracting the amount of electricity supplied in the downstream direction from the amount of electricity supplied in the upstream direction from the distribution line. Next, the operation of this embodiment will be described. The power distribution system management device 1 of this embodiment estimates the state of the power distribution lines 9-1 and 9-2 of the power distribution system by correcting the measured values ​​of the high-voltage sensor with the measured values ​​of the smart meter. Specifically, the power distribution system management device 1 calculates past power generation and load amounts using past measurement values ​​from high-voltage sensors 5-1 to 5-4 and smart meters, as well as solar power generation equipment data, at regular intervals, for example, every day, and stores the load amount as load data. As mentioned above, the measurement device 53 does not need to be installed, but if the measurement device 53 is installed, the above past measurement values ​​are the measurement values ​​from high-voltage sensors 5-1 to 5-4, smart meters, and the measurement device 53. Next, for each centralized control cycle, the power distribution system management device 1 estimates the current state of distribution lines 9-1 and 9-2 using load data and the current, or latest, measurement values, and controls the voltage control equipment connected to distribution lines 9-1 and 9-2 according to the estimated state. The centralized control cycle is, for example, 30 minutes, but is not limited to this. The power distribution system management device 1 may perform state estimation, i.e., estimation of the current state of distribution lines 9-1 and 9-2, at a shorter cycle than the centralized control cycle, such as 5 minutes or 1 minute. First, let's explain how to calculate past power generation and load amounts. Figure 6 is a flowchart showing an example of the procedure for calculating past power generation and load amounts in the power distribution system management device 1. In the power distribution system management device 1, the power generation estimation unit 11 estimates the past power generation amount for each solar power generation facility using past measurement values ​​from the smart meter and solar power generation facility data (step S11). As described above, if a measuring device 53 is installed, the power generation estimation unit 11 estimates the past power generation amount for each solar power generation facility using past measurement values ​​from the smart meter and measuring device 53 and solar power generation facility data. A smart meter for purchasing all generated electricity is installed for automatic meter reading. Using the readings from the smart meter, the power distribution system management device 1 can directly determine the amount of electricity generated by the corresponding solar power generation facility. On the other hand, for solar power generation facilities that are not compatible with smart meters for purchasing all generated electricity, the amount of electricity generated cannot be determined from the smart meter's readings. Since the amount of electricity generated by solar power generation facilities depends on the amount of solar radiation, and the amount of solar radiation changes depending on weather conditions, it is conceivable to estimate the amount of electricity generated by solar power generation facilities that are not compatible with smart meters for purchasing all generated electricity using the readings from smart meters located in a geographically close location. Figure 7 shows an example of the structure of measurement data transmitted by smart meters 31-1, 31-2, 32, and 33. As shown in Figure 7, the measurement data transmitted by smart meters 31-1, 31-2, 32, and 33 includes the SM number, which is a number used to identify the smart meter, and the measurement results, namely the amount of electricity used and the amount of electricity generated. The amount of electricity used and the amount of electricity generated are generally cumulative values, and the values ​​are updated every 30 minutes. That is, the amount of electricity used is a value obtained by sequentially adding up the amount of electricity used in the most recent 30 minutes, and the amount of electricity generated is a value obtained by sequentially adding up the amount of electricity generated in the most recent 30 minutes. Note that smart meters connected only to loads or only to solar power generation equipment do not need to include power generation or power consumption in their measurement data. However, for the sake of format standardization, we will assume that all smart meters transmit the measurement data shown in Figure 7. Furthermore, the format of the measurement data is not limited to Figure 7, and the format may be differentiated according to the measurement target of the smart meter. In addition, the measurement data may include information other than that shown in Figure 7. On the other hand, there are solar power generation facilities where there are no smart meters nearby that provide full purchase of electricity. Therefore, by installing measuring devices 53 that measure solar radiation, it is possible to estimate the amount of electricity generated by solar power generation facilities with greater accuracy. The measuring devices 53 are to be distributed as geographically as possible, and the measured values ​​from the measuring devices 53 are collected via the communication network 21 that constitutes the smart meter network. The smart meter network is a network used to collect measured values ​​from smart meters that measure electricity consumption, and includes the communication network 21 and the meter data management device 20. This eliminates the need to set up a new network for pyranometers, preventing cost increases and making it possible to determine the total amount of electricity generated by the distribution lines. Smart meters are assigned an SM number, which is a number used to identify them. In this embodiment, the measuring device 53 is also assigned an SM number, similar to the smart meter. Here, we have assigned SM numbers to the smart meter and the measuring device 53, but different numbering systems may be assigned to the smart meter and the measuring device 53. The format of the measurement data transmitted by the measuring device 53 can be, for example, the format shown in Figure 7, with the amount of power used and the amount of power generated replaced by solar radiation. When the meter data management device 20 receives measurement values ​​from the smart meter and the measuring device 53, it stores the received measurement data for 24 hours. Specifically, the communication unit 25 receives measurement values ​​from the smart meter and the measuring device 53 via the communication network 21, and the communication unit 25 determines whether the received data was transmitted from the smart meter or from the measuring device 53 based on the SM measurement data stored in the storage unit 24. The communication unit 25 stores the measurement data received from the smart meter as SM measurement data in the storage unit 24, and the measurement data received from the measuring device 53 as solar radiation measurement data in the storage unit 24. The data management unit 23 transmits the SM measurement data and solar radiation measurement data for one day to the power distribution system management device 1 via the communication unit 25. Note that, here, the meter data management device 20 accumulates data for 24 hours and transmits it in a batch, but the accumulation period is not limited to 24 hours. Also, the distribution system management device 1 may transmit the received data as it is to the distribution system management device 1. Note that, here, the distribution system management device 1 receives the SM measurement data and the solar radiation measurement data from the meter data management device 20 via the communication line, but the distribution system management device 1 may acquire the SM measurement data and the solar radiation measurement data via a medium other than the communication line. That is, the communication unit 16 is one form of the acquisition unit that acquires the SM measurement data and the solar radiation measurement data, and the acquisition unit may be an input unit that reads a medium or the like. FIG. 8 is a diagram showing a configuration example of load contract data. In the example shown in FIG. 8, the load contract data is composed of a number which is an identification number for each load, for example, for each customer, contract power, contract type, and business type. The contract type is, for example, a type of normal contract, late-night power contract, or contract with different rates depending on the time zone. Note that the contract type and business type may not be included in the load contract data. When estimating the load amount described later and calculating the load data according to the time zone and considering the contract type and business type for the estimation, the contract type and business type are included in the load contract data. FIG. 9 is a diagram showing a configuration example of the solar power generation facility data. As shown in FIG. 9, the solar power generation facility data of the present embodiment includes an SM number which is the SM number of the smart meter to which the solar power generation facility is connected, the latitude and longitude which are the installation positions of the solar power generation facility, the PV panel capacity which is the capacity of the solar panel (PV (PhotoVoltaics) panel) of the solar power generation facility, and a type indicating whether it is full-volume purchase or surplus purchase. The solar radiation meter position data includes the SM number which is the SM number of the measurement device 53, and the installation position of the solar radiation meter 52 of the measurement device 53, that is, the latitude and longitude which are the installation positions of the measurement device 53. Note that, hereinafter, each position of the solar radiation meter 52 of the measurement device 53 is referred to as the position of the measurement device 53. Also, the solar power generation facility connected to the full-volume purchase smart meter and the measurement device 53 are also referred to as measurement value known devices. The power generation amount estimation unit 11 refers to the solar power generation facility data and estimates, for example, the power generation amount of a solar power generation facility not connected to the full-purchase smart meter based on the measured values of three measurement value-known devices starting from the one closer to the solar power generation facility. When three measurement value-known devices starting from the one closer to the solar power generation facility are not installed with the measurement device 53, they are solar power generation facilities connected to the full-purchase smart meter. When the measurement device 53 is installed, they are the solar power generation facilities connected to the full-purchase smart meter and the measurement device 53. Taking an example where the measurement device 53 is installed, for example, assume that the three measurement value-known devices starting from the one closer to the solar power generation facility 4-1 are the solar power generation facility 4-2 and the measurement devices 53-1 and 53-2. At this time, the power generation amount estimation unit 11 extracts the measured value M of the power generation amount of the SM number corresponding to the solar power generation facility 4-1 from the SM measurement data, and extracts the PV panel capacities P 4-1 , P 4-1 corresponding to the solar power generation facilities 4-1 and 4-2 from the solar power generation facility data. 4-2 Also, the power generation amount estimation unit 11 extracts the measured values L 53-2 , L 53-1 corresponding to the SM numbers of the measurement devices 53-2 and 53-1 from the solar radiation amount measurement data respectively. The power generation amount estimation unit 11 calculates the estimated value E 4-2 of the power generation amount of the solar power generation facility 4-2 according to the following formula (1). α is a coefficient for converting the solar radiation amount into the ratio of the power generation amount to the panel capacity of the solar power generation facility (hereinafter also referred to as the power generation efficiency), and is a predetermined value. α may be changed for each season. Here, α is fixed without depending on the solar radiation meter, but α may be set for each solar radiation meter. The measured value of the solar radiation meter is assumed to be the solar radiation amount per unit area. E 4-2 = (M 4-1 ×P 4-2 / P 4-1 + α×P 4-2 ×(L 53-2 + L 53-1 )) / 3 …(1) In general, the following process is performed. If the three selected devices with known measurement values ​​include a solar power generation facility that is not connected to a smart meter for full purchase of electricity, the power generation estimation unit 11 calculates the power generation efficiency from the measured power generation of the solar power generation facility. Then, it calculates an individual estimated value by multiplying the calculated power generation efficiency by the PV panel capacity of the solar power generation facility to be estimated. Furthermore, if the three selected devices with known measurement values ​​include a measuring device 53, the power generation estimation unit 11 calculates an individual estimated value by multiplying a coefficient for converting solar radiation to power generation efficiency by the PV panel capacity of the solar power generation facility to be estimated and the measured value from the measuring device 53. Then, the power generation estimation unit 11 calculates the average value of the individual estimated values ​​from the three devices with known measurement values ​​as the estimated power generation. The power generation estimation unit 11 calculates the estimated power generation for all solar power generation facilities that are not connected to a smart meter for full purchase of electricity as described above. The power generation estimation unit 11 calculates the above power generation for each time period, for example, in 30-minute increments. Returning to the explanation of Figure 6, the power generation estimation unit 11 then calculates the total amount of power generated by the solar power generation equipment in a predetermined section, i.e., the total amount of power generated for each section (step S12). This section is a section in which the distribution line between two of the multiple high-voltage sensors is divided into multiple sections. For example, it can be a pole-mounted transformer unit, i.e., the space between a pole-mounted transformer and a pole-mounted transformer adjacent to it. In the following explanation, this section will be described as a pole-mounted transformer unit, but this section is not limited to pole-mounted transformer units. Any section obtained by dividing the space between two high-voltage sensors that measure the voltage and power flow of a distribution line into multiple sections is acceptable. Here, we will explain an example in which only the amount of power generated by the solar power generation equipment is considered as the amount of power generated. However, if other power generation equipment is connected to the distribution line, the amount of power generated by these equipment may be added to the total amount of power generated for each section. In this case, it is assumed that the amount of power generated by other power generation equipment is known, and the power generation estimation unit 11 adds a predetermined amount of power generated for each section. This predetermined amount of power generation may be set to a different value for each time period. Next, the load estimation unit 12 calculates the load amount for each section in the past based on the high-voltage sensors 5-1 to 5-4, the amount of power generated for each section calculated in step S12, and the load contract data (step S13). Specifically, the load estimation unit 12 first calculates the load amount for each section in the past based on past SM measurement data. More specifically, for each load stored in the load contract data, the load estimation unit 12 uses the amount of power used measured by the smart meter for loads where the amount of power used measured by the smart meter is stored in the SM measurement data, and uses the contract power for loads where the amount of power used measured by the smart meter is not stored in the SM measurement data, to calculate the total load amount for each section in each time period for each load. Next, the load estimation unit 12 uses the calculated power generation and load amounts for each section to distribute to each section the difference between the active power Pa measured by the high-voltage sensor at the outgoing point of each distribution line and the active power Pb measured by the high-voltage sensor at the end. Similarly, the load estimation unit 12 uses the calculated load amounts for each section to distribute to each section the difference between the reactive power Qa measured by the high-voltage sensor at the outgoing point of each distribution line and the reactive power Qb measured by the high-voltage sensor at the end. If capacitors are connected to distribution lines 9-1 and 9-2, the reactive power due to the capacitors is determined in advance. For example, since the active power generated by the capacitor does not change between day and night, the power generation at night when there is no power generation from sunlight is measured, and the reactive power Qc of the capacitor is determined with a power factor of 1. Using power distribution line 9-1 as an example, the explanation is as follows. Figure 10 shows the active power and reactive power distributed to each section of power distribution line 9-1. In Figure 10, power distribution line 9-1 is divided into four sections. The active power distributed to the i-th section (i = 1st, 2nd, 3rd, 4th) is P. i Let Q be the reactive power to be allocated to the i-th interval. i The power PG corresponding to the amount of power generated for each section. i The power corresponding to the load amount calculated for each section is PL iAccordingly, the load estimation unit 12 distributes the difference between the active power Pa measured by the high-voltage sensor and the active power Pb measured by the terminal high-voltage sensor to each section according to the following equation (2). Note that in the following equation (2), Σ represents the sum for i from i=1 to i=4. P i = ((PG i -PL i ) / Σ(PG i -PL i )) × (Pb - Pa) …(2) For reactive power, the value obtained by subtracting Qc from Qb - Qa is allocated to each section. For example, the load estimation unit 12 allocates reactive power to each section according to the following equation (3). Note that in this case, β = QL i / PL i Assuming that this is the case, γ = QG i / PG i The values ​​of β and γ are predetermined, and the load estimation unit 12 determines PG i , PL i From each QG i , QL i Calculate the following. For example, set β = γ = 0.1. Q i = ((QG i -QL i ) / Σ(QG i -QL i ))×(Qb-Qa-Qc) …(3) The load estimation unit 12, as described above, allocates P i and Q iUsing the voltage Va measured by a high-voltage sensor at the distribution line's outbound point, the load estimation unit 12 calculates the voltage in each section using power flow calculation. The voltage at the end calculated by this power flow calculation is denoted as Vd. If the difference between Vd and the voltage Vb measured by the high-voltage sensor at the end of the distribution line is less than or equal to a predetermined threshold, that is, if the measured voltage Vb and the calculated voltage are inconsistent, the load estimation unit 12 proceeds to step S14 shown in Figure 6. In other words, if the estimated voltage distribution does not match the voltages measured by the two high-voltage sensors, the unit proceeds to step S14. On the other hand, if the difference between Vd and the voltage Vb measured by the high-voltage sensor at the end of the distribution line is greater than a predetermined threshold, the load estimation unit 12 places virtual loads that generate reactive power with equal absolute values ​​but different signs at both ends between the measurement points. Figure 11 shows an example of virtual load placement. As shown in Figure 11, a virtual load generating +ΔQ is added to the upstream end between the measurement points, i.e., between high-voltage sensor 5-1 and high-voltage sensor 5-3, and a virtual load generating -ΔQ is added to the downstream end. After placing such virtual loads, the load estimation unit 12 performs the power flow calculation again. If Vd and voltage Vb match, the load estimation unit 12 proceeds to step S14 shown in Figure 6. If the difference between Vd and the voltage Vb measured by the high-voltage sensor at the end of the distribution line does not reach a predetermined threshold, the value of ΔQ is changed and the power flow calculation is repeated. Returning to the explanation of Figure 6, after step S13, the load estimation unit 12 stores the calculated load amount for each time period as load data in the storage unit 17 (step S14). At this time, if a virtual load is added, the virtual load is also included in the load data. Next, the current state estimation method and voltage control of this embodiment will be described. Figure 12 is a flowchart showing an example of the state estimation and voltage control procedure of this embodiment. The load calculation unit 13 and the power generation amount calculation unit 14 calculate the load / power generation amount for each section based on the latest sensor measurement value, i.e., the measurement value from the high-voltage sensor, and the load data (step S21). Specifically, first, the load calculation unit 13 calculates the current load amount for each section based on the load data. In detail, the load calculation unit 13 extracts the total load amount for the most recent period from the load data for the same time period as the current load, calculates the average value of the extracted total load amount, and sets the calculated average value as the current load amount. Alternatively, the load calculation unit 13 may calculate the average value for each temperature and time period based on load data for the past year, and use the average value corresponding to the current temperature and time period as the current total load. The temperature ranges are defined in 5-degree increments, for example, ..., 0°C-5°C, 5°C-10°C, ... Then, the average value of the total load for the past year is calculated for each temperature range and time period. Alternatively, the load calculation unit 13 may define weekdays and holidays as day-of-the-week categories and use the average value for each day-of-the-week category. Weekdays are defined as Monday through Friday, excluding public holidays, and holidays are defined as Saturday, Sunday, and public holidays. The load calculation unit 13 calculates the average load for each time period for each day-of-the-week category. The load calculation unit 13 then sets the average value corresponding to the current day-of-the-week category as the current load. The power generation calculation unit 14 then calculates the current total power generation based on the current load amount for each section obtained in step S21 and the current power flow measurement value from the high-voltage sensor. Based on the current total power generation, the power generation calculation unit 14 calculates the power generation amount for each section. For example, the power generation amount for each section is determined by setting a ratio for allocating the total power generation based on the total area of ​​the PV panels for each section, based on the solar power generation equipment data. Furthermore, if the measurement values ​​from the measuring device 53 can be acquired in near real-time, for example every minute, the power generation calculation unit 14 may also calculate the power generation amount using the measurement values ​​from the measuring device 53, i.e., the solar radiation diameter 2. That is, the power generation calculation unit 14 may estimate the power generation amount for each solar power generation equipment using the measurement device 53 and calculate the power generation amount for each section based on the estimated power generation amount. The method for estimating the power generation amount for each solar power generation equipment using the measurement values ​​from the measuring device 53 in the power generation calculation unit 14 can be the same as the estimation method in the power generation estimation unit 11, for example. Next, the voltage control unit 15 performs a power flow calculation based on the current load and power generation for each section and estimates the voltage distribution (step S22). Next, the voltage control unit 15 determines the optimal voltage distribution using the current load and power generation for each section and the voltage distribution (step S23). Any method can be used to determine the optimal voltage distribution, but for example, a power flow calculation is performed based on the current load and power generation for each section, and the optimal solution for the voltage at each point in the distribution line 9-1 is calculated so that each point falls within the appropriate voltage range. The optimal solution is the solution that minimizes a predetermined evaluation function. The evaluation function may include the difference between the appropriate voltage range and the voltage at each point in the distribution line 9-1. The voltage control unit 15 determines a voltage control amount based on the optimal voltage distribution (step S24). The voltage control unit 15 may control an optimal control amount, which is a control amount used to maintain the voltage calculated as the optimal voltage distribution, or it may determine information indicating upper and lower limits of the voltage control range determined based on the optimal control amount as the voltage control amount. The optimal control amount is a control amount commanded to each voltage control device so that the optimal voltage distribution is realized. The voltage control unit 15 transmits the determined voltage control amount to the voltage control device 80 via the communication unit 16. If there is a voltage control device controlled by the power distribution system management device 1 other than the voltage control device 80, the voltage control unit 15 also determines the control amount of that voltage control device and transmits the determined voltage control amount to that voltage control device via the communication unit 16. The voltage control unit 15 performs the above operations for each centralized control cycle. As described above, steps S21 and S22, which are processes up to the estimation of the voltage distribution, i.e., state estimation, may be performed at a shorter cycle than the centralized control cycle. As described above, the voltage control unit 15 has two functions: a state estimation unit that divides the power distribution line between two of the multiple high-voltage sensors into multiple sections and estimates the voltage distribution in the power distribution line based on two measured values ​​received from the two high-voltage sensors and the amount of power measured by a smart meter for each section; and a centralized voltage control unit that controls voltage control equipment based on the voltage distribution. The voltage control unit 15 may also be configured to be divided into a state estimation unit and a centralized voltage control unit. In the example shown in Figure 1, high-voltage sensors are installed at two locations: the discharge point and the terminal. However, high-voltage sensors may also be installed between the discharge point and the terminal. In this case as well, if the measured values ​​of two adjacent high-voltage sensors corresponding to the same distribution line are considered as the measured values ​​at the discharge point and the terminal, the distance between these two high-voltage sensor measurement points can be divided into sections, and the state of the distribution system can be estimated in a similar manner. As described above, in this embodiment, the voltage for each section of the distribution line is calculated using the measured values ​​from two high-voltage sensors in the high-voltage distribution line and the measured value from a smart meter. Furthermore, if there is a discrepancy between the measured value from the high-voltage sensors and the calculated voltage, a virtual load with the same absolute value but different signs is placed at both ends between the high-voltage sensors to correct the discrepancy. As a result, the state of the distribution system can be estimated with high accuracy. The configurations shown in the above embodiments are merely examples of the content of the present invention, and can be combined with other known technologies. It is also possible to omit or modify parts of the configuration without departing from the spirit of the present invention. 1 Distribution system management device, 2, 21 Communication network, 3-1 to 3-3 Load, 4-1, 4-2 Solar power generation equipment, 5-1 to 5-4 High voltage sensor, 6-1, 6-2 Circuit breaker, 7 Voltage control equipment, 8 Busbar, 9-1, 9-2 Distribution line, 11 Power generation amount estimation unit, 12 Load estimation unit, 13 Load calculation unit, 14 Power generation amount calculation unit, 15 Voltage control unit, 16, 25, 105 Communication unit, 17, 24, 103 Storage unit, 20 Meter data management device, 22 SM management unit, 23 Data management unit, 30-1 to 30-3 Consumer, 31-1, 31-2, 32, 33 Smart meter, 34 Electricity meter, 51 Communication unit, 52 Pyranometer, 53-1 to 53-2 Measuring device, 80 Voltage control device, 101 Control unit, 102 input unit, 104 display unit, 106 output unit, 107 system bus.