JP2024155399A - Information processing device, information processing method, and program - Google Patents

Abstract

[Problem] To easily estimate the power generation state of a photovoltaic power generation device in a power distribution system. [Solution] An information processing device 2 calculates the active power and reactive power of a power distribution system based on measured values of the voltage and current of the power distribution system measured by sensors 5, 11, 12, 91, and 92. In an orthogonal coordinate system in which the active power is the first axis and the reactive power is the second axis, and the first and second axes are orthogonal to each other, a point determined by the active power and reactive power of a power distribution system 10 to be determined at a predetermined time or time period is a reference point P0, and a point determined by the active power and reactive power of the power distribution system 10 to be determined at a time or time period to be determined is a determination point Px. Based on the direction of a vector Bx connecting the reference point P0 to the determination point Px, the information processing device 2 determines whether or not power is being generated by a photovoltaic power generation device 61 connected to the power distribution system 10 to be determined at a time or time period to be determined. [Selected Figure] FIG.

Description

The present invention relates to an information processing device, an information processing method, and a program, for example, an information processing device, an information processing method, and a program for estimating the power generation state of a photovoltaic power generation device connected to a power distribution system.

The widespread use of solar power generation equipment installed at general consumers has resulted in complex voltage fluctuations in the power distribution system due to weather, time of day, etc. Conventionally, voltage adjustments in the power distribution system have been performed by workers visiting the site and changing settings related to tap switching control, etc., set in voltage control devices such as LRTs (Load Ratio Control Transformers) installed at substations and SVRs (Step Voltage Regulators) installed on distribution lines (self-end control method). However, in recent years, in order to respond to voltage fluctuations in the power distribution system due to weather, time of day, etc., the introduction of a centralized voltage control method to replace the conventional self-end control method is progressing.

The centralized voltage control method is a method in which the voltage, current, etc. in the distribution system are measured using sensors built into switches and voltage regulators installed in the distribution system, appropriate setting values are calculated based on these measurements, and voltage control devices such as LRTs and SVRs are controlled via a communication network (see Patent Document 1).

The centralized voltage control method makes it possible to adjust the voltage at locations where sensors are installed in a power distribution system to an appropriate value. However, since voltage measurements cannot be obtained at locations where sensors are not installed, such as high-voltage branch lines and low-voltage systems in the power distribution system, some ingenuity is required to appropriately adjust the voltage at these locations. For example, taking into account the voltage difference between locations where sensors are installed and locations where sensors are not installed in the power distribution system, it is necessary to determine the setting value of the voltage regulator based on the voltage measurements at locations where sensors are installed in the power distribution system so that the voltage at locations where sensors are not installed falls within an acceptable range.

However, the voltage difference between the location where the sensor is installed and the location where the sensor is not installed in the power distribution system is highly dependent on the power generation state of the photovoltaic power generation device connected to the power distribution system. Therefore, in order to set the voltage regulator to an appropriate value, it is necessary to take into account the power generation state of the photovoltaic power generation device.

As a method for understanding the power generation status of a photovoltaic power generation device connected to a power distribution system, for example, Patent Document 2 discloses a technology for calculating the amount of power generated by a photovoltaic power generation device using meteorological data.

JP 2012-217248 A JP 2022-121028 A

However, in order to grasp the power generation status of the photovoltaic power generation device using meteorological data as in Patent Document 2, it is necessary to periodically synchronize the meteorological data with the calculation processing based on the centralized voltage control method, which leads to a complex system.

The inventors of the present application therefore considered estimating the amount of power generated by a photovoltaic power generation device from the measurements of sensors installed in a power distribution system. Power simply calculated from the measurements of sensors installed in a power distribution system contains a mixture of power consumed by the load and power generated by the photovoltaic power generation device. Therefore, it is necessary to separate the power generated by the photovoltaic power generation device from the power calculated from the measurements of each sensor. However, it is not easy to separate the power generated by the photovoltaic power generation device from the power calculated from the measurements of the sensors.

The present invention was made in consideration of the above-mentioned problems, and aims to make it possible to easily estimate the power generation state of a solar power generation device in a power distribution system.

The information processing device according to a representative embodiment of the present invention is characterized by having a measurement result acquisition unit that acquires measured values of the voltage and current of the power distribution system measured by a sensor, a power calculation unit that calculates the active power and reactive power of the power distribution system based on the measured values acquired by the measurement result acquisition unit, a vector calculation unit that calculates a vector connecting the reference point and the judgment target point in an orthogonal coordinate system in which the active power is a first axis and the reactive power is a second axis and the first axis and the second axis are orthogonal to each other, the reference point is a point determined by the active power and the reactive power of the power distribution system to be judged at a predetermined time or time period, and the judgment target point is a point determined by the active power and the reactive power of the power distribution system to be judged at the judgment target time or time period, and the power generation judgment unit that judges whether or not power is generated by a solar power generation device connected to the power distribution system to be judged at the judgment target time or time period based on the direction of the vector.

The information processing device according to the present invention makes it possible to easily estimate the power generation state of a photovoltaic power generation device in a power distribution system.

1 is a diagram showing a configuration of a power supply system including an information processing device according to an embodiment; FIG. 2 is a diagram showing an example of voltage in a power distribution system. 1 is a scatter plot of actual measured values of active power and reactive power at a start-up point of a power distribution system. 1 is a scatter plot of actual measured values of active power and reactive power at a start-up point of a power distribution system. 1 is a scatter plot of actual measured values of active power and reactive power at a start-up point of a power distribution system. 4 is a diagram for explaining a method for estimating a power generation state of a photovoltaic power generation device by a centralized control system according to an embodiment. FIG. FIG. 1 is a diagram for explaining a method for estimating the amount of power generated by a solar power generation device. 1 is a block diagram showing a configuration of a centralized control system according to an embodiment; 5 is a flowchart showing an example of a process flow for estimating a power generation state of a photovoltaic power generation device in the centralized control system according to the embodiment. FIG. 2 is a diagram showing changes in power generation rate over time in one power distribution system. FIG. 2 is a diagram showing changes in power generation rate over time in one power distribution system. FIG. 2 is a diagram showing changes in power generation rate over time in one power distribution system.

1. Overview of the embodiment First, an overview of a representative embodiment of the invention disclosed in this application will be described. Note that in the following description, as an example, reference numerals in the drawings corresponding to components of the invention are given in parentheses.

[1] An information processing device (2) according to a representative embodiment of the present invention includes a measurement result acquisition unit (21) that acquires measured values of the voltage and current of a power distribution system measured by sensors (5, 11, 12, 91_1 to 91_4, 92, 92_1 to 92_4), a power calculation unit (22) that calculates active power and reactive power of the power distribution system based on the measured values acquired by the measurement result acquisition unit, and a power calculation unit (23) that calculates the active power and reactive power of the power distribution system to be determined at a predetermined time or time period in an orthogonal coordinate system in which the active power is on a first axis and the reactive power is on a second axis, the first axis and the second axis being orthogonal to each other. The system is characterized by having a vector calculation unit (23) that calculates a vector connecting a point determined by the active power and the reactive power of the distribution system to be judged at a time or time period to be judged from the reference point (P0) and a point determined by the active power and the reactive power of the distribution system to be judged at a time or time period to be judged as a judgment target point (Px), and a power generation judgment unit (27) that judges whether or not power is being generated by a solar power generation device connected to the distribution system to be judged at the time or time period to be judged based on the direction of the vector.

[2] In the information processing device (2) described in [1] above, the vector calculation unit may calculate an angle between the vector and either one of the first axis or the second axis, as the direction of the vector, and the power generation determination unit may determine whether or not power is being generated by the solar power generation device based on the magnitude of the angle.

[3] In the information processing device described in [2] above, when the reactive power when the current lags the voltage is set to positive, the vector calculation unit calculates the angle (θ) of the vector with respect to the positive direction of the first axis, and the power generation determination unit may determine that there is no power generation by the solar power generation device connected to the distribution system at the time or time period to be determined when the angle is in the range of 0° to 90°, and may determine that there is power generation by the solar power generation device connected to the distribution system at the time or time period to be determined when the angle is in the range of 90° to 180°.

[4] In the information processing device described in [1] above, the reference point may be a point determined by the active power and the reactive power at a time or time period during a day when the active power of the distribution system being evaluated is at a minimum.

[5] The information processing device described in [1] above may further include a power generation amount calculation unit (28) that calculates the power generation amount of the photovoltaic power generation device connected to the distribution system to be judged based on the amount of change in apparent power at the judgment target point relative to the apparent power at the reference point.

[6] In the information processing device described in [5] above, the power generation amount calculation unit may calculate the amount of change (ΔS) in the apparent power based on the magnitude of the vector.

[7] In the information processing device described in [6] above, the power generation amount calculation unit may further calculate a power generation rate (R) which is the ratio of the power generation amount to a PV interconnection amount (Pa), which is the total value of the maximum power generation amount of each of the photovoltaic power generation devices connected to the distribution system to be determined.

[8] The information processing method according to a representative embodiment of the present invention includes a first step (S1) of acquiring measured values of the voltage and current of the power distribution system measured by a sensor; a second step (S2) of calculating the active power and reactive power of the power distribution system based on the measured values acquired in the first step; a third step (S3) of calculating a vector connecting the reference point and the judgment target point in an orthogonal coordinate system in which the active power is the first axis and the reactive power is the second axis and the first axis and the second axis are orthogonal to each other, the reference point being a point determined by the active power and reactive power of the power distribution system to be judged at a predetermined time or time period, and the point determined by the active power and reactive power of the power distribution system to be judged at the time or time period being judged; and a fourth step (S4, S5, S6, S7) of judging the presence or absence of power generation by a photovoltaic power generation device connected to the power distribution system to be judged at the time or time period being judged based on the direction of the vector.

[9] A program according to a representative embodiment of the present invention is characterized in that it causes a computer (2) to execute a first step (S1) of acquiring measured values of the voltage and current of the power distribution system measured by a sensor, a second step (S2) of calculating the active power and reactive power of the power distribution system based on the measured values acquired in the first step, a third step (S3) of calculating a vector connecting the reference point and the judgment point in an orthogonal coordinate system in which the active power is the first axis, the reactive power is the second axis, and the first axis and the second axis are orthogonal to each other, the reference point is a point determined by the active power and the reactive power of the power distribution system to be judged at a predetermined time or time period, and the judgment point is a point determined by the active power and the reactive power of the power distribution system to be judged at the judgment time or time period, and the judgment point is a fourth step (S4, S5, S6, S7) of judging the presence or absence of power generation by a photovoltaic power generation device connected to the power distribution system to be judged at the judgment time or time period based on the direction of the vector.

2. Specific Examples of the Embodiments Specific examples of the embodiments of the present invention will be described below with reference to the drawings. In the following description, components common to the respective embodiments are designated by the same reference numerals, and repeated description will be omitted.

<Embodiment>
FIG. 1 is a diagram showing a configuration of a power supply system 100 including an information processing device according to an embodiment.

The power supply system 100 shown in FIG. 1 is a system that supplies power from a higher-level system including a distribution substation 4 to multiple power supply paths 10_1 to 10_n (n is an integer of 2 or more) via distribution circuit breakers 7_1 to 7_n (n is an integer of 2 or more).

In this embodiment, as shown in FIG. 1, the power supply paths 10_1 to 10_n formed on the secondary side of each of the distribution circuit breakers 7_1 to 7_n are also referred to as "power distribution systems 10_1 to 10_n." For example, as shown in FIG. 1, the power distribution systems 10_1 to 10_n are connected to each other via switches or the like to form a power supply network that supplies power supplied from a higher-level system to each consumer.

In this specification, when describing components such as distribution circuit breakers 7_1 to 7_n, if there is no need to distinguish between the components, they may be referred to as "distribution circuit breaker 7" without a suffix.

The power supply system 100 stabilizes the power supply to each of the power distribution systems 10_1 to 10_n, for example, by using a centralized voltage control method. Specifically, an information processing device such as a server installed in the control center 1 receives physical quantities related to the power supply, such as voltage and current, measured by various sensors installed in the power distribution substation 4 and each of the power distribution systems 10_1 to 10_n via a communication network, and controls the voltage regulators 5, 11, 12 and switches 91, 92, etc. installed in the power distribution substation 4 and each of the power distribution systems 10_1 to 10_n based on the measured values of the received physical quantities.

As shown in FIG. 1, the power supply system 100 includes, for example, a distribution substation 4, a secondary busbar 6, distribution circuit breakers 7_1 to 7_n, distribution systems 10_1 to 10_n, and a control center 1.

The distribution substation 4 transforms the power supplied to a primary bus (not shown) from a large-scale power plant such as a thermal power plant, and outputs the power to a secondary bus 6 (e.g., a 6 kV bus). A plurality of distribution circuit breakers 7_1 to 7_n are connected to the secondary bus 6. When the distribution circuit breakers 7_1 to 7_n are closed, power is supplied from the secondary bus 6 connected to the primary side of the distribution circuit breakers 7_1 to 7_n to the distribution systems 10_1 to 10_n connected to the secondary side of the distribution circuit breakers 7_1 to 7_n, and when the distribution circuit breakers 7_1 to 7_n are opened, the power supply from the secondary bus 6 to the distribution systems 10_1 to 10_n is stopped. Each distribution circuit breaker 7_1 to 7_n can be controlled individually. The opening and closing of the distribution circuit breakers 7_1 to 7_n is controlled, for example, by an information processing device (e.g., an optical central unit, etc.) installed in the distribution substation 4.

The distribution substation 4 is provided with a voltage regulator 5. The voltage regulator 5 is a device that controls the voltage supplied from a primary bus (not shown) to a secondary bus 6. The voltage regulator 5 is, for example, an on-load tap changer (LRT). The voltage regulator 5 includes, for example, a transformer, a tap changer, a sensor, a communication device, and the like (not shown). The transformer transforms the voltage of the primary bus (not shown) and outputs it to the secondary bus 6. The tap changer adjusts the voltage output from the transformer by switching the tap of the transformer winding according to tap switching information (setting value) received by a communication device described later. The sensor measures physical quantities such as the voltage and current on the primary and secondary sides of the transformer. The communication device communicates with an external information processing device, etc., via a known communication network such as an Internet line or optical communication. For example, the communication device transmits the measurement results by the sensor to the distribution control system 3, and also receives tap switching information from the distribution control system 3 and provides it to the tap changer.

The power distribution systems 10_1 to 10_n are, for example, known power supply networks in which multiple distribution lines are connected via multiple switches. As an example, FIG. 1 representatively illustrates a power distribution system 10_1 in which multiple distribution lines 81 are connected via multiple switches 91_1 to 91_4 and a voltage regulator 11, and a power distribution system 10_2 in which multiple distribution lines 81 are connected via multiple switches 92_1 to 92_4 and a voltage regulator 12.

In FIG. 1, only the components of the power distribution systems 10_1 and 10_2 necessary for explaining the present invention are shown as representative components, and other components are omitted. Furthermore, the number of distribution lines 81, switches 91 and 92, and voltage regulators 11 and 12 provided in each of the power distribution systems 10_1 to 10_n is not limited to the example shown in FIG. 1. In this embodiment, the power distribution systems 10_3 to 10_n are also assumed to have the same configuration as the power distribution systems 10_1 and 10_2, and the power distribution systems 10_1 and 10_2 will be described as representative components.

The switches 91 and 92 are devices connected between adjacent distribution lines 81 and switch between electrical connection and disconnection (opening and closing) between one distribution line 81 and the other distribution line 81. For example, the switches 91 and 92 are automatic switches.

The switches 91 and 92 can be opened and closed by remote control by the power distribution control system 3. For example, the power distribution control system 3 and the switches 91 and 92 can communicate with each other via the above-mentioned publicly known communication network. When the power distribution control system 3 transmits an "open" instruction to the switch 91_1, which is in a closed state, the switch 91_1 changes from a closed state to an open state. In addition, when the switches 91 and 92 detect that the power supply to the distribution line 81 connected to the primary side of the switches 91 and 92 has stopped, the switches change from a "closed state" to an "open state". The switches 91 and 92 may have an opening and closing function based on, for example, a time-limited accident investigation method.

At least one of the switches 91, 92 provided in each of the power distribution systems 10_1 to 10_n is, for example, a switch with a built-in sensor (sensor-equipped switch). In addition to the functions of a conventional switch, the sensor-equipped switch has the function of measuring various physical quantities related to the power supply, such as the voltage and current on at least one of the primary and secondary sides of the switch, using the sensor and transmitting the measured values to an external device.

In this embodiment, for example, among the multiple switches 91, 92 provided in each of the power distribution systems 10_1 to 10_n, at least the switches 91_1, 92_1 provided at the most upstream of the power distribution system 10 (for example, the rising point of the power distribution system 10) are switches with sensors.

The switches 91_1 and 92_2 transmit the measured current and voltage measurements of the power distribution systems 10_1 and 10_2 to the power distribution control system 3 via a publicly known network.

The voltage regulators 11 and 12 are devices connected between adjacent distribution lines and control the voltage supplied from one distribution line to the other distribution line. The voltage regulators 11 and 12 are, for example, automatic voltage regulators (SVRs). The voltage regulators 11 and 12 are, for example, equipped with a transformer, a tap changer, a sensor, a communication device, etc. (not shown) similar to the voltage regulator 5. The transformer transforms the voltage of the primary distribution line 81 and outputs it to the secondary distribution line 81. The tap changer adjusts the voltage output from the transformer by switching the tap of the transformer winding according to tap switching information (setting value) received by the communication device described later. The sensor measures physical quantities such as the voltage and current on the primary and secondary sides of the transformer. The communication device communicates with external information processing devices, etc. via a known communication network such as the Internet line or optical communication. For example, the communication device transmits the measurement results from the sensor to the power distribution control system 3, and receives tap switching information from the power distribution control system 3 and provides it to the tap changer.

Each of the power distribution systems 10_1 to 10_n is connected to a number of consumers (consumer equipment) that receive a supply of electric power. At least some of the consumer equipment includes a distributed power supply device.

A distributed power supply device is a device that outputs generated or stored electricity. The distributed power supply device is linked to one of the power distribution systems 10_1 to 10_n, and the electricity generated or stored by the distributed power supply device can be supplied to the power distribution system.

Examples of distributed power supply devices include emergency generators that generate power based on mechanical energy, such as photovoltaics (PV) and diesel generators (emergency DG). In this embodiment, as shown in FIG. 1, a photovoltaic power supply device (PV) 61 as a distributed power supply device is described as being connected to each distribution system 10_1_10_n.

The control center 1 is a facility in which various devices are installed that monitor the power distribution system (upper system and lower system) within the power supply system 100 and control the supply and stop of power in the power distribution system. The control center 1 has, for example, a power distribution control system 3 and a centralized control system 2.

The distribution control system 3 communicates between the voltage regulator 5 etc. of the distribution substation 4 described above and the voltage regulators 11, 12, various sensors, switches, and other devices provided in each distribution system, which will be described later, via a known communication network such as the Internet line or optical communication. The distribution control system 3 receives measurement results from the voltage regulator 5 and the voltage regulators 11, 12 and switches 91, 92 of each distribution system 10_1 to 10_n via the communication network. The distribution control system 3 is also capable of sending and receiving data to and from the centralized control system 2.

The centralized control system 2 acquires measurement results and the like received from the voltage regulator 5 and various devices of each distribution system via the distribution control system 3, and performs arithmetic processing based on the acquired measurement results and the like to calculate control information such as setting values of the voltage regulators 5, 11, and 12 and operation information for operating the switches 91 and 92, and provides this to the distribution control system 3. The distribution control system 3 controls the voltage regulators 5, 11, and 12 and the switches 91 and 92 by transmitting the control information provided by the centralized control system 2 to the voltage regulators 5, 11, and 12 and the switches 91 and 92 via a communication network. For example, the distribution control system 3 controls the opening and closing of the switches 91 and 92 based on the operation information received from the centralized control system 2, and sets the setting values received from the centralized control system 2 to the voltage regulators 5, 11, and 12.

The power distribution control system 3 and the centralized control system 2 are realized by an information processing device that performs program processing, such as a server. The power distribution control system 3 and the centralized control system 2 are realized, for example, by separate information processing devices. The power distribution control system 3 may be realized by one information processing device, or may be realized by multiple information processing devices. Similarly, the centralized control system 2 may be realized by one information processing device, or may be realized by multiple information processing devices.

The centralized control system 2 generates tap switching information as a set value for the voltage regulators 5, 11, and 12 based on the measurement results measured by the voltage regulator 5, switches 91 and 92 installed in each distribution system 10_1 to 10_n, and voltage regulators 11 and 12, and controls the voltage of each distribution system 10_1 to 10_n to be within the allowable range by switching the taps of the voltage regulators 5, 11, and 12 based on the tap switching information via the distribution control system 3.

Figure 2 shows an example of voltage in a power distribution system.

In FIG. 2, the horizontal axis represents time, and the vertical axis represents voltage. Reference numeral 201 represents the change over time in the voltage (measured voltage) measured by the switch with sensor at the location where the switch with sensor is installed in the distribution system. Reference numeral 202 represents the change over time in the voltage at the customer facility (end customer) connected downstream from the location where the switch with sensor is installed in the distribution system.

The centralized control system 2 controls the voltage in each distribution system 10 to be within a predetermined range, for example, between 95V and 107V, by switching the taps of the voltage regulators 5, 11, and 12 via the distribution control system 3.

In general, the voltage in a distribution system varies depending on the distance from a substation, the presence or absence of power generation by distributed power sources such as photovoltaic power generation devices, and the power usage status at the consumer. For example, as can be seen from reference numerals 201 and 202 in FIG. 2, the voltage at the location where the sensor-equipped switch is installed in the distribution system differs from the voltage at the consumer equipment (end consumer) connected downstream from the location where the sensor-equipped switch is installed. In particular, when the consumer equipment (end consumer) includes a photovoltaic power generation device and the photovoltaic power generation device is generating power, the photovoltaic power generation device supplies power to the distribution system 10, so that the voltage at the end consumer becomes higher than the voltage at the location where the sensor-equipped switch is installed, as shown in FIG. 2. Even in such a case, it is necessary to make the voltage at the end consumer fall within the range of 95V to 107V.

However, as described above, while it is possible to measure the voltage at locations in the power distribution system 10 where sensors such as voltage regulators 11 and 12 and switches 91 and 92 (switches with sensors) are installed, it is not possible to measure the voltage at locations in the power distribution system 10 where sensors are not installed.

Therefore, the centralized control system 2 sets a lower voltage limit value Vlth and an upper voltage limit value Vuth that determine the allowable voltage range, taking into account the voltage difference between locations where sensors are installed and locations where sensors are not installed in the power distribution system. For example, as shown in FIG. 2, the lower voltage limit value Vlth is set to a value higher than 95 V, and the upper voltage limit value Vuth is set to a value lower than the range of 107 V. The centralized control system 2 then calculates tap switching information as the setting value for the voltage regulators 5, 11, and 12 so that the measured voltage at the locations where sensors are installed falls within the range determined by the lower voltage limit value Vlth and the upper voltage limit value Vuth. This makes it possible to control the voltage to fall within the range of 95 V to 107 V even at locations where sensors are not installed.

On the other hand, as described above, the voltage difference between the location where the sensor is installed and the location where the sensor is not installed in the distribution system is largely dependent on the power generation state of the photovoltaic power generation device connected to the distribution system. Therefore, in order to ensure that the voltage at the location where the sensor is not installed falls within the range of 95V to 107V, it is necessary to set an appropriate voltage lower limit value Vlth and voltage upper limit value Vuth, taking into account the power generation state of the photovoltaic power generation device connected to the distribution system 10.

The centralized control system 2 according to the embodiment generates control information including set values such as tap switching information, lower voltage limit Vlth, and upper voltage limit Vuth, and has an equipment control function for controlling the voltage regulators 5, 11, and 12 based on the control information, as well as a power generation estimation function for estimating the power generation state of the photovoltaic power generation device connected to the power distribution system 10. The power generation estimation function includes a function for determining whether or not the photovoltaic power generation device is generating power, and a function for estimating the amount of power generated by the photovoltaic power generation device.

First, we will explain the power generation estimation function, which determines whether or not the solar power generation device is generating power.

Figures 3 and 4 are scatter plots of the actual measured values of active power and reactive power at the start-up point of a power distribution system.

In Figures 3 and 4, the horizontal axis (X-axis) represents active power [kW], and the vertical axis (Y-axis) represents reactive power [kvar]. In the following explanation, reactive power is considered positive when the phase of the current lags the phase of the voltage. That is, in Figures 3 and 4, the positive direction of the Y-axis is the direction in which the current lags the phase of the voltage, and the negative direction of the Y-axis is the direction in which the current leads the phase of the voltage.

Figure 3 plots the measured values of active power and reactive power measured every hour on May 4, 2021 (weather: sunny) at the start-up point of the distribution system to which the solar power generation device is connected. Reference symbol 301 represents the direction of time change of the measured values of active power and reactive power in the morning of that day, and reference symbol 302 represents the direction of time change of the measured values of active power and reactive power in the afternoon of that day.

As can be seen from Figure 3, in the morning, there is a tendency for active power to decrease and lagging reactive power to increase over time. This is thought to be due to an increase in reverse power flow to the distribution system and an increase in the supply of lagging reactive power as the power generation by the solar power generation device increases. On the other hand, in the afternoon, there is a tendency for active power to increase and lagging reactive power to decrease over time. This is thought to be due to a decrease in reverse power flow to the distribution system and a decrease in the supply of lagging reactive power as the power generation by the solar power generation device decreases.

In FIG. 4, the measured values of active power and reactive power measured hourly at the start-up point of the distribution system to which the photovoltaic power generation device is connected are plotted on a sunny day (May 4, 2021), a cloudy day (May 15, 2021), and a rainy day (May 27, 2021). Reference numeral 301 indicates the direction of time change of the measured values of active power and reactive power in the morning of that day, and reference numeral 302 indicates the direction of time change of the measured values of active power and reactive power in the afternoon of that day.

In Figure 4, the plots shown with circles represent the measured active and reactive power values on a sunny day, the plots shown with squares represent the measured active and reactive power values on a cloudy day, and the plots shown with diamonds represent the measured active and reactive power values on a rainy day.

As can be seen from Figure 4, the range in which the measured values of active power and reactive power are plotted varies depending on the weather. That is, the range in which the measured data pairs of active power and reactive power are plotted narrows on sunny days, followed by cloudy days and rainy days. This is thought to be because the amount of power generated by the solar power generation device decreases on sunny days, followed by cloudy days and rainy days.

As can be seen from Figures 3 and 4, it is possible to understand the power generation state of the solar power generation device from the trajectory and range of the plot of the measured values of active power and reactive power in the power distribution system.

Next, we explain a method for estimating the power generation state of a photovoltaic power generation system based on plots of measured values of active power and reactive power in a power distribution system.

Figure 5 shows a scatter plot of the actual measured values of active power and reactive power at the start-up point of a power distribution system.

In Fig. 5, as in Fig. 3 and Fig. 4, the horizontal axis (X axis) represents active power [kW], and the vertical axis (Y axis) represents reactive power [kvar]. In Fig. 5, the positive direction of the Y axis represents the direction in which the current lags the voltage, and the negative direction of the Y axis represents the direction in which the current leads the voltage.

Figure 5 plots the measured values of active power and reactive power measured every hour on May 4, 2021 (weather: sunny) at the start-up point of the distribution system to which the solar power generation device is connected (PV connection amount: 3,844 kW), which is a different point from Figure 3. Reference numeral 501 represents the range that includes the measured values of active power and reactive power at the time when power generation was generated by the solar power generation device on the day of measurement (daytime), and reference numeral 502 represents the range that includes the measured values of active power and reactive power at the time when power generation was not generated by the solar power generation device on the day of measurement (nighttime).

Here, the reference point is a point determined by the active power and reactive power of the distribution system to be evaluated at a specific time or time period. For example, the reference point is a point determined by the measured values of active power and reactive power at a time or time period when power generation by the solar power generation device is not (is deemed not to be) generated. For example, as shown in FIG. 5, in an orthogonal coordinate system in which active power is the first axis (X-axis) and reactive power is the second axis (Y-axis) and the first and second axes are orthogonal, consider a case in which the reference point P0 is determined by the active power and reactive power at a time of day when the active power of the distribution system 10 to be evaluated is the smallest (for example, 2:00 a.m.).

In this case, the plot of the measured values of active power and reactive power when there is power generation by the solar power generation device is distributed diagonally upward to the right (negative direction of the X-axis and positive direction of the Y-axis) as seen from reference point P0, as shown in Figure 5. On the other hand, the plot of the measured values of active power and reactive power when there is no power generation by the solar power generation device is distributed diagonally upward to the left (positive direction of the X-axis and positive direction of the Y-axis) as seen from reference point P0, as shown in Figure 5.

The centralized control system 2 according to the embodiment uses a Cartesian coordinate system with active power as the first axis (X-axis) and reactive power as the second axis (Y-axis) to determine a point determined by the active power and reactive power of the distribution system to be determined at the time or time period to be determined as a determination point Px, and estimates the power generation state of the photovoltaic power generation device connected to the distribution system to be determined at the time or time period to be determined based on the positional relationship between the determination point Px and the reference point P0.

Figure 6 is a diagram for explaining a method for estimating the power generation state of a solar power generation device using a centralized control system 2 according to an embodiment.

In Fig. 6, similar to Fig. 3, the horizontal axis (X-axis) represents active power [kW], and the vertical axis (Y-axis) represents reactive power [kvar]. In Fig. 6, the positive direction of the Y-axis represents the direction in which the current lags the voltage, and the negative direction of the Y-axis represents the direction in which the current leads the voltage.

The centralized control system 2 determines whether or not power is being generated by the photovoltaic power generation device connected to the power distribution system 10 at the time or time period of the judgment point Px based on the direction of the judgment point Px from the reference point P0.

For example, the centralized control system 2 identifies the direction of a vector Bx connecting a reference point P0 to a judgment target point Px in an orthogonal coordinate system with active power as the first axis (X-axis) and reactive power as the second axis (Y-axis), and determines whether or not power is being generated by a solar power generation device connected to the power distribution system 10 at the time or time zone of the judgment target point Px based on the identified direction of vector Bx.

Here, the reference point P0 is a point determined by the active power and reactive power at a specific time or time period. For example, as described above, the reference point P0 is a point determined by the measured values of active power and reactive power at a time or time period when power generation by the solar power generation device is not occurring (is considered not to be occurring). Preferably, the reference point P0 is a point determined by the measured values of active power and reactive power at night (e.g., the time period from after sunset to before sunrise). More preferably, as described above, the reference point P0 is a point determined by the active power and reactive power at a time of day when the active power of the distribution system 10 being evaluated is the smallest.

As shown in FIG. 6, when determining the direction of vector B1 connecting reference point P0 to judgment target point P1, centralized control system 2 calculates the angle (angle θ) between vector B1 and either one of the first axis (X axis) or second axis (Y axis) of the Cartesian coordinate system. Also, for example, when determining the direction of vector B2 connecting reference point P0 to judgment target point P2, centralized control system 2 calculates the angle (angle) θ between vector B2 and either one of the first axis (X axis) or second axis (Y axis) of the Cartesian coordinate system.

For example, for vector B1, the centralized control system 2 calculates the angle θ1 of vector B1 relative to the first axis (X-axis) representing active power, and for vector B2, calculates the angle θ2 of vector B2 relative to the first axis (X-axis) representing active power.

The centralized control system 2 determines whether or not power is being generated by the photovoltaic power generation device based on the magnitude of the angle θ. Specifically, if the angle θ is in the range of 0° to 90° (0°≦θ<90°) out of the range of 0° to 180°, the centralized control system 2 determines that there is no power generation by the photovoltaic power generation device connected to the distribution system being determined. On the other hand, if the angle θ is not in the range of 0° to 90° (0°≦θ<90°) out of the range of 0° to 180°, that is, if the angle θ is in the range of 90° to 180° (90°<θ≦180°), the centralized control system 2 determines that there is power generation by the photovoltaic power generation device connected to the distribution system being determined.

For example, because the angle θ1 of vector B1 is in the range of 0° to 90° (0°≦θ<90°), the centralized control system 2 determines that there is no power generation by the photovoltaic power generation device connected to the distribution system 10 being determined at the time or time period of the determination point P1 of vector B1. On the other hand, because the angle θ2 of vector B2 is in the range of 90° to 180° (90°≦θ≦180°), the centralized control system 2 determines that there is power generation by the photovoltaic power generation device connected to the distribution system 10 being determined at the time or time period of the determination point P2 of vector B2.

Next, we will explain the power generation estimation function, which estimates the amount of power generated by a solar power generation device.

Figure 7 is a diagram for explaining a method for estimating the amount of power generated by a solar power generation device.

In Fig. 7, similar to Fig. 3, the horizontal axis (X-axis) represents active power [kW], and the vertical axis (Y-axis) represents reactive power [kvar]. In Fig. 7, the positive direction of the Y-axis represents the direction in which the current lags the voltage, and the negative direction of the Y-axis represents the direction in which the current leads the voltage.

The centralized control system 2 calculates the amount of power generated by the photovoltaic power generation device based on the amount of change in apparent power at the judgment target point Px relative to the apparent power at the reference point P0. Specifically, the centralized control system 2 calculates the amount of change in apparent power from the reference point P0 to the judgment target point Px based on the magnitude of the vector Bx connecting the reference point P0 to the judgment target point Px in an orthogonal coordinate system consisting of a first axis (X-axis) and a second axis (Y-axis), i.e., the movement distance ΔS from the reference point P0 to the judgment target point Px in the orthogonal coordinate system.

For example, when the active power of the reference point P0 is x0, the reactive power is y0, and the active power of the judgment target point Px is x1, and the reactive power is y1, the travel distance (vector magnitude) ΔS from the reference point P0 to the judgment target point Px can be expressed by the following formula (1).

Based on the above formula (1), the centralized control system 2 calculates the travel distance ΔS from the reference point P0 to the judgment target point Px, and regards it as the amount of power generated by the photovoltaic power generation device at the time or time period of the judgment target point Px. In other words, the centralized control system 2 regards the travel distance ΔS as an estimate of the total amount of power generated by all the photovoltaic power generation devices 61 connected to the distribution system 10 being judged.

The centralized control system 2 further calculates the power generation rate R in the power distribution system based on the power generation amount ΔS by the photovoltaic power generation device. Specifically, the centralized control system 2 calculates the ratio of the power generation amount ΔS to the PV interconnection amount Pa of the power distribution system 10 as the power generation rate R.

Here, the PV interconnection amount Pa is the sum of the maximum power generation amount (maximum rated output) of each photovoltaic power generation device 61 connected to the distribution system being evaluated.

The centralized control system 2 calculates the power generation rate R, for example, based on the following formula (2):

Next, we will explain the specific configuration of the centralized control system 2 for realizing the above-mentioned equipment control function and power generation estimation function.

Figure 8 is a block diagram showing the configuration of the centralized control system 2 according to the embodiment.

Although not shown, the information processing device serving as the centralized control system 2 has hardware resources constituting, for example, a program processing device such as a server. That is, the information processing device has, for example, a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), a LAN interface (LAN_I/F), an external interface I/F, a bus, and various peripheral circuits.

As shown in FIG. 8, the centralized control system 2 has a measurement result acquisition unit 21, a power calculation unit 22, a vector calculation unit 23, a power generation determination unit 27, a power generation amount calculation unit 28, a control unit 29, and a memory unit 30 as functional blocks for realizing the above-mentioned equipment control function and power generation estimation function.

These functional blocks are realized by the cooperation of the hardware and software resources provided in the information processing device serving as the centralized control system 2 described above. That is, the measurement result acquisition unit 21, power calculation unit 22, vector calculation unit 23, power generation determination unit 27, power generation amount calculation unit 28, control unit 29, and memory unit 30 are realized by the CPU performing various calculations according to programs stored in memory such as RAM and ROM, and controlling the LAN interface and various peripheral circuits based on the calculation results.

The memory unit 30 is a functional unit for storing various data such as parameters and calculation results required for the device control function and power generation estimation function. For example, the memory unit 30 stores measurement results 31, power information 32, vector information 33, power generation information 34, PV grid-connected information 35, and control information 36, which will be described later.

The measurement result acquisition unit 21 acquires voltage and current measurements taken by sensors provided in at least one power distribution system 10 to which power is supplied from a higher-level system. Specifically, the measurement result acquisition unit 21 receives voltage and current measurements taken by the voltage regulators 5, 11, 12 and switches 91, 92 (sensor-equipped switches) from the power distribution control system 3, and stores the voltage and current measurements in the memory unit 30 as measurement results 31. Here, the above sensors may include, for example, not only the sensors built into the voltage regulators 5, 11, 12 and switches 91, 92 described above, but also other sensors provided in the power distribution system 10.

The power calculation unit 22 calculates the active power and reactive power of the power distribution system 10 based on the measurement values acquired by the measurement result acquisition unit 21. For example, the power calculation unit 22 calculates the apparent power, active power, and reactive power per unit time for each of the power distribution systems 10_1 to 10_n using a known calculation method based on the measured values of voltage and current per unit time and the phase difference between the voltage and current as the measurement results 31 stored in the memory unit 30, and stores them in the memory unit 30 as power information 32.

Specifically, the power calculation unit 22 calculates the power based on the voltage and current measured by sensors installed at the rising points of each of the power distribution systems 10_1 to 10_n. For example, when calculating the power of the power distribution system 10_2, the power calculation unit 22 calculates the measured values of the apparent power, active power, and reactive power per unit time based on the measured values of the voltage and current per unit time measured by the switch 92_1 at the rising point of the power distribution system 10_2, and stores them in the memory unit 30 as the power information 32 of the power distribution system 10_2. By using the measured values of the voltage and current at the rising point of the power distribution system 10, it is possible to estimate the overall power downstream of the rising point of the power distribution system 10.

In addition, the power calculation unit 22 may calculate the average values of apparent power, active power, and reactive power for each time period (e.g., every hour) and store them as power information 32.

The vector calculation unit 23 calculates a vector Bx that connects the reference point P0 to the determination point Px. For example, the vector calculation unit 23 includes a vector identification unit 24, an angle calculation unit 25, and a movement distance calculation unit 26.

The vector identification unit 24 identifies a vector Bx of the judgment target point Px in an orthogonal coordinate system with the active power as the first axis and the reactive power as the second axis based on the active power and reactive power as the power information 32 stored in the memory unit 30.

For example, consider the case where the presence or absence of power generation by the photovoltaic power generation device 61 in the power distribution system 10_2 at 11:00 a.m. is determined. In this case, the vector identification unit 24 first identifies the reference point P0. For example, the vector identification unit 24 sets the reference point P0 to a point on an orthogonal coordinate system determined by the measured values of active power and reactive power at the time when the active power is smallest among the measured values of active power and reactive power for each time included in the power information 32 of the power distribution system 10_2. For example, as described above, if the active power is smallest at 2:00 a.m., the reference point P0 is set to a point on an orthogonal coordinate system determined by the measurement points of the active power and reactive power at 2:00 a.m.

Next, the vector identification unit 24 reads out the measured values of active power and reactive power at 11:00 a.m. from the power information 32, and sets the point on the Cartesian coordinate system determined by the read-out measured values as the judgment target point Px. Then, the vector identification unit 24 identifies the vector connecting the reference point P0 to the judgment target point Px as the vector Bx of the judgment target point Px.

The angle calculation unit 25 calculates the angle (angle θ) between the vector Bx and either one of the first axis (X-axis, active power) and the second axis (Y-axis, reactive power) of the Cartesian coordinate system as the direction of the vector Bx identified by the vector identification unit 24. For example, the angle calculation unit 25 calculates the angle θ between the vector Bx and the positive direction of the first axis (X-axis, active power) (see FIG. 6).

The movement distance calculation unit 26 calculates the movement distance ΔS from the reference point P0 to the judgment point Px, i.e., the magnitude of the vector Bx. For example, in the above example, the movement distance calculation unit 26 calculates the movement distance ΔS based on the above formula (1).

The reference point P0, the judgment target point Px, the angle θ, and the movement distance ΔS calculated by the vector identification unit 24, the angle calculation unit 25, and the movement distance calculation unit 26 are stored in the memory unit 30 as vector information 33 for each of the power distribution systems 10_1 to 10_n.

Based on the direction of the vector Bx, the power generation determination unit 27 determines whether or not power is being generated by the solar power generation device connected to the distribution system 10 being determined at the time or time period being determined. For example, in the above example, the power generation determination unit 27 first reads out the angle θ of the vector Bx at 11:00 a.m. in the distribution system 10_2 as the determination target point Px from the vector information 33 stored in the memory unit 30. The power generation determination unit 27 determines whether or not power is being generated by the solar power generation device in the distribution system 10_2 based on the magnitude of the read angle θ.

Specifically, if the angle θ is in the range of 0° to 90° (0°≦θ<90°), it is determined that there is no power generation by the solar power generation device connected to the power distribution system 10_2 at 11:00 a.m., and if the angle θ is in the range of 90° to 180° (90°≦θ≦180°), it is determined that there is power generation by the solar power generation device connected to the power distribution system 10_2 at 11:00 a.m.

The power generation amount calculation unit 28 calculates the power generation amount of the photovoltaic power generation device in the distribution system 10 to be judged based on the change in apparent power at the judgment point Px relative to the apparent power at the reference point P0. As described above, the magnitude of the vector Bx, i.e., the movement distance ΔS from the reference point P0 to the judgment point Px, represents the change in apparent power from the reference point P0 to the judgment point Px. Therefore, the power generation amount calculation unit 28 regards the movement distance ΔS as an estimated value of the power generation amount of the photovoltaic power generation device connected to the distribution system 10 to be judged at the time or time zone of the judgment point Px. In the above example, the power generation amount calculation unit 28 regards the movement distance ΔS based on the vector Bx of the distribution system 10_2 at 11:00 a.m. as the power generation amount ΔS by the photovoltaic power generation device connected to the distribution system 10_2 at 11:00 a.m.

The power generation calculation unit 28 also calculates the power generation rate R. For example, in the above example, the power generation calculation unit 28 calculates the power generation rate R by substituting the PV interconnection amount Pa of the distribution system 10_2 to be judged and the power generation amount ΔS by the photovoltaic power generation device in the distribution system 10_2 at 11:00 a.m. into the above formula (2).

Here, the PV interconnection amount Pa for each of the power distribution systems 10_1 to 10_n is stored in advance in the storage unit 30 as PV interconnection information 35. In addition, the determination result by the power generation determination unit 27 and the power generation amount ΔS and power generation rate R calculated by the power generation amount calculation unit 28 are stored in the storage unit 30 as power generation information 34 for each power distribution system 10.

The control unit 29 controls the voltage regulator 5, and the voltage regulators 11, 12 and switches 91, 92 in each of the power distribution systems 10_1 to 10_n. For example, the control unit 29 calculates tap switching information for the voltage regulators 5, 11, and 12, and calculates the upper voltage limit Vuth and the lower voltage limit Vlth, based on the result of determining whether or not power is being generated by the photovoltaic power generation devices in each of the power distribution systems 10_1 to 10_n described above, and the amount of power generation or the power generation rate by the photovoltaic power generation devices in each of the power distribution systems 10_1 to 10_n.

The control unit 29 also calculates operation information for the switches 91 and 92 in each of the power distribution systems 10_1 to 10_n by monitoring the power, voltage, current, and the like in each of the power distribution systems 10_1 to 10_n. The calculated tap switching information and operation information for the switches 91 and 92, and the like are stored in the storage unit 30 as control information 36.

The control unit 29 controls the voltage regulators 5, 11, and 12 and the switches 91 and 92 by transmitting the calculated tap switching information and operation information of the switches 91 and 92 to the voltage regulators 5, 11, and 12 and the switches 91 and 92 via the power distribution control system 3.

Next, we will explain the process flow for estimating the power generation state of the solar power generation device in the centralized control system 2.

Figure 9 is a flowchart showing an example of the process flow for estimating the power generation state of a solar power generation device in the centralized control system 2.

First, in the centralized control system 2, the measurement result acquisition unit 21 acquires measurement values such as voltage and current from the voltage regulator 5, voltage regulators 11 and 12, and switches 91 and 92 via the power distribution control system 3, and stores them in the memory unit 30 as measurement results 31 (step S1).

Next, the power calculation unit 22 calculates physical quantities (measured values) related to power, such as apparent power, reactive power, and active power, in each of the power distribution systems 10_1 to 10_n based on the measurement results of the voltage, current, etc. stored in the memory unit 30 in step S1, using the method described above, and stores them in the memory unit 30 as power information 32 (step S2).

Next, based on the power information 32 stored in the memory unit 30 in step S2, the vector calculation unit 23 identifies a vector Bx of the judgment target point Px, which is identified by the measured values of the active power and reactive power of the judgment target power distribution system 10 at the judgment target time or time period in an orthogonal coordinate system with active power as the first axis and reactive power as the second axis (step S3). Specifically, the vector identification unit 24 identifies the reference point P0 and the judgment target point Px in the orthogonal coordinate system with active power as the first axis and reactive power as the second axis by the above-mentioned method, and identifies the vector connecting the reference point P0 to the judgment target point Px as the vector Bx of the judgment target point Px.

Next, the vector calculation unit 23 identifies the direction of the vector Bx of the determination point Px (step S4). Specifically, the angle calculation unit 25 calculates the angle (angle θ) between the first axis (X-axis, active power) of the Cartesian coordinate system and the vector Bx as the direction of the vector Bx identified by the vector identification unit 24 using the method described above.

Next, the power generation determination unit 27 determines whether the angle θ calculated in step S5 is in the range of 0° to 90° (0°≦θ<90°) (step S5).

If the angle θ calculated in step S5 is in the range of 0° to 90° (0°≦θ<90°) within the range of 0° to 180° (step S5: YES), the power generation determination unit 27 determines that there is no power generation by the photovoltaic power generation device in the specified distribution system 10 at the time or time period of the determination target point Px (step S6). After that, the centralized control system 2 ends the series of processes.

On the other hand, if the angle θ is not in the range of 0° to 90° (0°≦θ<90°) within the range of 0° to 180°, i.e., if the angle θ is in the range of 90° to 180° (90°<θ≦180°) (step S5: NO), the power generation determination unit 27 determines that power generation is occurring by the photovoltaic power generation device in the specified distribution system 10 at the time or time period of the determination target point Px (step S7).

Next, the power generation amount calculation unit 28 calculates the amount of power generated by the photovoltaic power generation device connected to the distribution system 10 determined in step S7 to be generating power by the photovoltaic power generation device (step S8). Specifically, the power generation amount calculation unit 28 calculates the magnitude of the vector Bx of the determination target point Px identified in step S3, i.e., the travel distance ΔS from the reference point P0 on the above-mentioned orthogonal coordinate system to the determination target point Px, using the method described above, and sets this as the amount of power generated ΔS by the photovoltaic power generation device connected to the distribution system 10 to be determined at the time or time period to be determined. The amount of power generated ΔS is stored in the storage unit 30 as power generation information 34.

Furthermore, the power generation calculation unit 28 calculates the power generation rate R of the photovoltaic power generation device connected to the distribution system 10 for which it was determined in step S7 that the photovoltaic power generation device is generating power (step S9). Specifically, the power generation calculation unit 28 calculates the power generation rate R of the photovoltaic power generation device connected to the distribution system 10 for the time or time period to be determined based on the power generation amount ΔS calculated in step S8 and the PV interconnection amount Pa stored in the storage unit 30 using the method described above, and stores the power generation information 34 in the storage unit 30.

By using the above processing procedure, the centralized control system 2 determines whether or not power is being generated by the photovoltaic power generation device for each of the power distribution systems 10_1 to 10_n at the time or time period to be determined, and calculates the amount of power generated by the photovoltaic power generation device ΔS and the power generation rate R.

The centralized control system 2 may also determine the weather based on the power generation rate R calculated using the method described above.

Figures 10A, 10B, and 10C are diagrams showing the change over time in the power generation rate R of a photovoltaic power generation device in one power distribution system 10.

Figure 10A shows the power generation rate R of a solar power generation device in one distribution system for each unit time from 6:00 am to 7:00 pm on a sunny day (May 4, 2021). Figure 10B shows the power generation rate per unit time of a solar power generation device in one distribution system for each unit time from 6:00 am to 7:00 pm on a cloudy day (May 15, 2021). Figure 10C shows the power generation rate R of a solar power generation device in one distribution system for each unit time from 6:00 am to 7:00 pm on a rainy day (May 27, 2021).

As can be seen from FIG. 10A, there tends to be more time periods during which the power generation rate R exceeds 50% on sunny days. Therefore, the power generation determination unit 27 of the centralized control system 2 may determine that the weather is "sunny" for the time or time period during which the power generation rate R exceeds a first threshold value (e.g., 50%).

As can be seen from FIG. 10C, there tends to be many time periods on rainy days when the power generation rate R is less than 25%. Therefore, the power generation determination unit 27 of the centralized control system 2 may determine that the weather is "rainy" for a time or time period when the power generation rate R is less than a second threshold value (e.g., 25%).

As can be seen from FIG. 10B, there tends to be many time periods on cloudy days when the power generation rate R is 25% or more and less than 50%. Therefore, the power generation determination unit 27 of the centralized control system 2 may determine that the weather is "cloudy" for a time or time period when the power generation rate R is equal to or more than the second threshold and less than the first threshold (25%≦R<50%).

In this way, the centralized control system 2 may perform a process to determine the weather based on the power generation rate R.

As described above, the information processing device as the centralized control system 2 according to the embodiment calculates active power and reactive power based on the measured values of voltage and current measured by sensors such as voltage regulators 11, 12 and switches 91, 92 provided in at least one distribution system 10 to which power is supplied from a higher-level system. The information processing device sets active power as the first axis (e.g., X-axis) and reactive power as the second axis (e.g., Y-axis), and sets a point determined by a data pair including active power and reactive power of the distribution system 10 to be determined at night in an orthogonal coordinate system in which the first and second axes are orthogonal to each other as a reference point P0, and sets a point in the orthogonal coordinate system determined by a data pair including active power and reactive power at the time or time period to be determined from the reference point P0 as a determination target point Px. The information processing device calculates a vector Bx connecting the reference point P0 to the determination target point Px, and determines whether or not power is generated by a photovoltaic power generation device connected to the distribution system 10 to be determined at the time or time period to be determined based on the direction of the vector Bx.

According to this, it is possible to determine whether or not a photovoltaic power generation device in a distribution system to be determined is occurring without separating the power generated by the photovoltaic power generation device from the power calculated from the measurement values of the sensors in the distribution system to be determined, and it is also possible to determine whether or not a photovoltaic power generation device in the distribution system to be determined is occurring. In addition, it is not necessary to use meteorological data.
Therefore, according to the information processing device according to the embodiment, it is possible to easily estimate the power generation state of a photovoltaic power generation device in a power distribution system.

In addition, the information processing device of the embodiment calculates the angle (angle θ) between either the first axis or the second axis and the vector Bx as the direction of the vector Bx of the judgment target point Px, and determines whether or not power is being generated by the solar power generation device based on the magnitude of the angle θ.
This makes it possible to easily calculate the direction of the vector Bx of the determination point Px.

Furthermore, the information processing device according to the embodiment calculates the angle θ of the vector Bx with respect to the positive direction of the first axis when reactive power is positive when the current lags behind the voltage. When the angle θ is in the range of 0° to 90°, the information processing device determines that there is no power generation by the photovoltaic power generation device connected to the distribution system 10 to be determined at the time or time period to be determined, and when the angle θ is in the range of 90° to 180°, the information processing device determines that there is power generation by the photovoltaic power generation device connected to the distribution system 10 to be determined at the time or time period to be determined.
This makes it possible to easily determine whether or not power is being generated by a photovoltaic power generation device in a power distribution system.

In addition, in the information processing device according to the embodiment, among the points determined by the active power and reactive power during the night, the point determined by the active power and reactive power at the time or time period when the active power is at a minimum is set as the reference point P0.
According to this, the position of the judgment point Px can be identified based on a point when no power generation is being performed by the solar power generation device, making it possible to judge the power generation state of the solar power generation device with higher accuracy.

Moreover, the information processing device according to the embodiment calculates the power generation amount ΔS of the photovoltaic power generation device based on the amount of change in apparent power at the judgment point Px relative to the apparent power at the reference point P0. In other words, the information processing device calculates the amount of change in apparent power based on the magnitude (movement distance ΔS) of the vector Bx.
This makes it possible to easily obtain an estimate of the amount of power generated by a photovoltaic power generation device in the distribution system 10 to be evaluated, without performing complex calculations.

In addition, the information processing device according to the embodiment calculates the ratio of the power generation amount ΔS to the PV interconnection amount Pa, which is the total value of the maximum power generation amounts of each of the photovoltaic power generation devices connected to the power distribution system 10, and sets this as the power generation rate R.
This makes it possible to easily estimate the amount of power generated by the photovoltaic power generation device in the target power distribution system 10. In addition, as described above, it is also possible to estimate the weather at the target time or time zone based on the power generation rate.

<<Extension of the embodiment>>
The invention made by the inventor has been specifically described above based on an embodiment, but it goes without saying that the invention is not limited thereto and can be modified in various ways without departing from the spirit of the invention.

For example, the case where the power distribution control system 3 and the centralized control system 2 are realized by separate information processing devices has been exemplified, but this is not limited thereto, and the power distribution control system 3 and the centralized control system 2 may be realized by a single information processing device, or may be integrated into a single system consisting of multiple information processing devices. Furthermore, the power distribution control system 3 and the centralized control system 2 do not necessarily need to be provided in the same control center 1 (site), and each may be provided in a different location.

In the above embodiment, the method of determining the power generation state of a photovoltaic power generation device connected downstream of the rising point of the power distribution system 10 using the measured values of the voltage and current at the rising point of the power distribution system 10 is exemplified, but this is not limited to the above. For example, by performing a calculation using the above-mentioned method using the power calculated based on the voltage and current measured by a specific sensor in the distribution system 10 to be determined, it is possible to determine the power generation state of a photovoltaic power generation device connected downstream of the specific sensor. For example, by calculating active power and reactive power using the voltage and current measured by the voltage regulator 12 of the power distribution system 10_2 and performing a calculation using the above-mentioned method using the active power and reactive power, it is possible to determine the power generation state of a photovoltaic power generation device connected downstream of the voltage regulator 12 in the power distribution system 10_2.

The above-mentioned flowchart shows an example for explaining the operation, and is not limited to this. In other words, the steps shown in each figure of the flowchart are specific examples, and are not limited to this flow. For example, the order of some of the processes may be changed, other processes may be inserted between each process, and some processes may be performed in parallel.

1...Control center, 2...Centralized control system (information processing device), 3...Distribution control system (information processing device), 4...Distribution substation, 5...Voltage regulator (LRT), 6...Secondary busbar, 7_1 to 7_n...Distribution circuit breakers, 10_1 to 10_n...Distribution system (power supply network), 11, 12...Voltage regulator (SVR), 21...Measurement result acquisition unit, 22...Power calculation unit, 23...Vector calculation unit , 24...vector determination unit, 25...angle calculation unit, 26...travel distance calculation unit, 27...power generation determination unit, 28...power generation amount calculation unit, 29...control unit, 30...storage unit, 31...measurement results, 32...power information, 33...vector information, 34...power generation information, 35...PV interconnection information, 36...control information, 61...photovoltaic power generation device (PV), 81...power distribution line, 91_1 to 91_4, 92_1 to 92_4...switches.

Claims (9)

a measurement result acquisition unit that acquires measured values of voltage and current of the power distribution system measured by a sensor;
a power calculation unit that calculates active power and reactive power of the power distribution system based on the measurement values acquired by the measurement result acquisition unit;
a vector calculation unit that calculates a vector connecting the reference point and the determination point in an orthogonal coordinate system in which the active power is defined as a first axis and the reactive power is defined as a second axis, the first axis and the second axis being orthogonal to each other, the reference point being a point determined by the active power and the reactive power of the distribution system to be determined at a predetermined time or time period, and the determination point being a point determined by the active power and the reactive power of the distribution system to be determined at a time or time period being a determination point;
and a power generation determination unit that determines whether or not power is being generated by a photovoltaic power generation device connected to the distribution system at the time or time period to be determined based on a direction of the vector. 2. The information processing device according to claim 1,
the vector calculation unit calculates, as a direction of the vector, an angle between the vector and one of the first axis and the second axis;
The information processing device, wherein the power generation determination unit determines whether or not power generation is occurring by the solar power generation device based on the magnitude of the formed angle. 3. The information processing device according to claim 2,
When the reactive power is positive when the current lags the voltage, the vector calculation unit calculates an angle of the vector with respect to a positive direction of the first axis;
The information processing device, wherein the power generation determination unit determines that there is no power generation by the solar power generation device connected to the power distribution system being determined at the time or time period being determined when the angle is in the range of 0° to 90°, and determines that there is power generation by the solar power generation device connected to the power distribution system being determined at the time or time period being determined when the angle is in the range of 90° to 180°. 2. The information processing device according to claim 1,
The reference point is a point determined by the active power and the reactive power at a time or time period during a day when the active power of the distribution system to be determined is at a minimum. 2. The information processing device according to claim 1,
The information processing device further comprises a power generation amount calculation unit that calculates a power generation amount of the photovoltaic power generation device connected to the distribution system to be determined based on an amount of change in apparent power at the determination point relative to the apparent power at the reference point. 6. The information processing device according to claim 5,
The information processing device, wherein the power generation amount calculation unit calculates an amount of change in the apparent power based on a magnitude of the vector. 7. The information processing device according to claim 6,
The power generation amount calculation unit further calculates a power generation rate, which is a ratio of the power generation amount to a PV interconnection amount, which is a total value of maximum power generation amounts of the photovoltaic power generation devices connected to the distribution system to be determined. A first step of obtaining measurements of voltage and current in the power distribution system measured by sensors;
a second step of calculating active power and reactive power of the power distribution system based on the measured values acquired in the first step;
a third step of calculating a vector connecting the reference point and the target point in an orthogonal coordinate system in which the active power is a first axis and the reactive power is a second axis and the first axis and the second axis are orthogonal to each other, the reference point being a point determined by the active power and the reactive power of the distribution system to be determined at a predetermined time or time period, and the target point being a point determined by the active power and the reactive power of the distribution system to be determined at a target time or time period, and calculating a vector connecting the reference point and the target point;
and a fourth step of determining, based on a direction of the vector, whether or not power is being generated by a photovoltaic power generation device connected to the distribution system to be determined at the time or time period to be determined. A first step of obtaining measurements of voltage and current in the power distribution system measured by sensors;
a second step of calculating active power and reactive power of the power distribution system based on the measured values acquired in the first step;
a third step of calculating a vector connecting the reference point and the target point in an orthogonal coordinate system in which the active power is a first axis and the reactive power is a second axis and the first axis and the second axis are orthogonal to each other, the reference point being a point determined by the active power and the reactive power of the distribution system to be determined at a predetermined time or time period, and the target point being a point determined by the active power and the reactive power of the distribution system to be determined at a target time or time period, and calculating a vector connecting the reference point and the target point;
and a fourth step of determining whether or not power is being generated by a solar power generation device connected to the distribution system to be determined at the time or time period to be determined based on a direction of the vector.

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