JPWO2019150777A1 - Monitoring device and judgment method - Google Patents

Abstract

The monitoring device is a monitoring device used in a photovoltaic power generation system in which an output line from a power generation unit including a solar cell panel is electrically connected to a power conversion device, and acquires a current measurement result of the power generation unit. It includes an acquisition unit, the operating state of the power conversion device that is determined based on the measurement result, the determined operating state, and a determination unit that determines an abnormality based on the measurement result.

Description

The present invention relates to a monitoring device and a determination method.
This application claims priority on the basis of Japanese application Japanese Patent Application No. 2018-16842 filed on February 2, 2018, and incorporates all of its disclosures herein.

Japanese Patent Application Laid-Open No. 2012-205878 (Patent Document 1) discloses the following monitoring system for photovoltaic power generation. That is, the photovoltaic power generation monitoring system is a photovoltaic power generation monitoring system that monitors the power generation status of the solar panel with respect to the photovoltaic power generation system that aggregates the outputs from the plurality of solar panel and sends them to the power conversion device. Therefore, a measuring device that is provided at a place where output electric circuits from the plurality of solar panel panels are integrated and measures the amount of power generated by each solar panel, and a measuring device that is connected to the measuring device and has a power generation amount by the measuring device. The solar panel via a lower communication device having a function of transmitting measurement data, an upper communication device having a function of receiving the measurement data transmitted from the lower communication device, and the upper communication device. It is provided with a management device having a function of collecting the measurement data for each. The management device determines the presence or absence of an abnormality based on the difference in the amount of power generation at the same time point for each of the solar cell panels, or the maximum value or the total amount of the amount of power generation for each of the solar cell panels for a predetermined period. The presence or absence of an abnormality is determined based on the value.

Japanese Unexamined Patent Publication No. 2012-205878

(1) The monitoring device of the present disclosure is a monitoring device used in a photovoltaic power generation system in which an output line from a power generation unit including a solar cell panel is electrically connected to a power conversion device, and the current of the power generation unit. It is provided with an acquisition unit that acquires the measurement result of the above, the operation state that determines the operating state of the power conversion device based on the measurement result, and a determination unit that determines an abnormality based on the measurement result.

(7) The determination method of the present disclosure is a determination method in a monitoring device used in a photovoltaic power generation system in which an output line from a power generation unit including a solar cell panel is electrically connected to a power conversion device. A step of acquiring the measurement result of the current of the unit, a step of determining the operating state of the power conversion device based on the measurement result, a step of determining the determined operating state, and a step of determining an abnormality based on the measurement result. including.

One aspect of the present disclosure can be realized not only as a monitoring device provided with such a characteristic processing unit, but also as a program for causing a computer to execute such a characteristic processing. Further, one aspect of the present disclosure may be realized as a semiconductor integrated circuit that realizes a part or all of the monitoring device, or may be realized as a system including the monitoring device.

FIG. 1 is a diagram showing a configuration of a photovoltaic power generation system according to an embodiment of the present invention. FIG. 2 is a diagram showing a configuration of a PCS unit according to an embodiment of the present invention. FIG. 3 is a diagram showing a configuration of a current collector unit according to an embodiment of the present invention. FIG. 4 is a diagram showing a configuration of a solar cell unit according to an embodiment of the present invention. FIG. 5 is a diagram showing a configuration of a power generation state determination system according to an embodiment of the present invention. FIG. 6 is a diagram showing a configuration of a monitoring device in the power generation state determination system according to the embodiment of the present invention. FIG. 7 is a diagram showing an example of normal string current data in the power generation state determination system according to the embodiment of the present invention. FIG. 8 is a diagram showing an example of a state in which the output line from the power generation unit in the photovoltaic power generation system according to the embodiment of the present invention is short-circuited between the positive and negative electrodes. FIG. 9 is a diagram showing an example of string current data in an output line short-circuited between positive and negative electrodes in the power generation state determination system according to the embodiment of the present invention. FIG. 10 is a diagram showing a short-circuit failure of the backflow prevention diode in the power generation state determination system according to the embodiment of the present invention. FIG. 11 is a diagram showing an example of string current data of a power generation unit corresponding to a backflow prevention diode having a short-circuit failure in the power generation state determination system according to the embodiment of the present invention. FIG. 12 is a diagram showing another example in which the output line from the power generation unit in the photovoltaic power generation system according to the embodiment of the present invention is short-circuited between the positive and negative electrodes. FIG. 13 is a diagram showing another example of string current data in an output line short-circuited between positive and negative electrodes in the power generation state determination system according to the embodiment of the present invention. FIG. 14 is a diagram showing the relationship between the output current and the output voltage of the power generation unit in the power generation state determination system according to the embodiment of the present invention. FIG. 15 is a flowchart defining an operation procedure when the monitoring device according to the embodiment of the present invention determines an abnormality. FIG. 16 is a flowchart defining an operation procedure when the monitoring device according to the embodiment of the present invention determines an abnormality in a stopped state of the PCS. FIG. 17 is a flowchart defining an operation procedure when the monitoring device according to the embodiment of the present invention determines an abnormality in the operating state of the PCS.

In recent years, techniques for monitoring a photovoltaic power generation system and discriminating abnormalities have been developed.

[Issues to be solved by this disclosure]
A technique capable of improving the abnormality determination of the photovoltaic power generation system beyond the technique described in Patent Document 1 is desired.

The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide a monitoring device and a determination method capable of improving the abnormality determination of a photovoltaic power generation system.

[Effect of the present disclosure]
According to the present disclosure, it is possible to improve the abnormality determination of the photovoltaic power generation system.

[Explanation of Embodiments of the Invention]
First, the contents of the embodiments of the present invention will be listed and described.

(1) The monitoring device according to the embodiment of the present invention is a monitoring device used in a photovoltaic power generation system in which an output line from a power generation unit including a solar cell panel is electrically connected to a power conversion device. A determination unit that acquires a measurement result of the current of the power generation unit, a determination that determines the operating state of the power conversion device based on the measurement result, and a determination that determines an abnormality based on the determined operating state and the measurement result. It has a part.

With such a configuration, the operating state of the power converter is determined using the current measurement result of the power generation unit, and the abnormality determination is performed using the current measurement result of the power generation unit. be able to. Thereby, the abnormality in the photovoltaic power generation system can be satisfactorily determined. Therefore, it is possible to improve the abnormality determination of the photovoltaic power generation system.

(2) Preferably, the determination unit determines that the operating state of the power conversion device is in the stopped state, and determines an abnormality based on the measurement result in the stopped state.

In this way, focusing on the measurement result of the current of the power generation unit when the power conversion device is stopped, and determining the abnormality using the measurement result of the output current of the power generation unit, the abnormality in the photovoltaic power generation system can be judged well. can do.

(3) More preferably, the measuring unit for measuring the current of the power generation unit is connected between the power generation unit and the power conversion device, and the determination unit indicates the output current of the power generation unit. Based on the above, an abnormality in the circuit between the measuring unit and the power conversion device is determined.

With such a configuration, it is possible to satisfactorily determine the abnormality of the circuit between the measuring unit and the power conversion device by using the measurement result of the output current of the power generation unit.

(4) More preferably, in the photovoltaic power generation system, a plurality of output lines from the power generation unit are aggregated at the aggregation unit and electrically connected to the power conversion device, and the backflow prevention diode is used for the plurality of power generation. The measuring unit, which is connected between the power generation unit and the aggregation unit of a part or all of the units and measures the current of the corresponding power generation unit, is the backflow corresponding to the power generation unit of the part or all. Connected to the prevention diode, the determination unit determines an abnormality of the backflow prevention diode based on the measurement result indicating the backflow current to the part or all of the power generation units.

With such a configuration, the abnormality of the backflow prevention diode can be satisfactorily determined by using the measurement result of the backflow current to the power generation unit.

(5) Preferably, the measuring unit for measuring the current of the power generation unit is connected between the power generation unit and the power conversion device, and the determination unit is in the operating state of the power conversion device. Based on the measurement result indicating the output current of the power generation unit in the operating state of the power conversion device, it is determined that there is an abnormality in the circuit between the power generation unit and the measurement unit.

In this way, by focusing on the measurement result of the current of the power generation unit in the operating state of the power conversion device and determining the abnormality using the measurement result of the output current of the power generation unit, the abnormality of the circuit between the power generation unit and the measurement unit is determined. Can be satisfactorily determined.

(6) More preferably, in the solar power generation system, a plurality of output lines from the power generation unit are aggregated in the aggregation unit and electrically connected to the power conversion device, and the current of the corresponding power generation unit is measured. The measuring unit is connected between a part or all of the plurality of power generation units and the power conversion device among the plurality of power generation units, and the determination unit is the one in the operating state of the power conversion device. Based on the measurement result indicating the output currents of the unit or all of the plurality of power generation units, the abnormality of the circuit between the measurement unit and the aggregation unit is determined.

In this way, focusing on the measurement result of the current of the power generation unit in the operating state of the power conversion device, and determining the abnormality using the measurement result of the output current of each power generation unit, the circuit between the measurement unit and the aggregation unit Abnormality can be judged well.

(7) The determination method according to the embodiment of the present invention is a determination method in a monitoring device used in a photovoltaic power generation system in which an output line from a power generation unit including a solar cell panel is electrically connected to a power conversion device. There is a step of acquiring the measurement result of the current of the power generation unit, a step of determining the operating state of the power conversion device based on the measurement result, the determined operating state, and an abnormality based on the measurement result. Includes a step to determine.

With such a configuration, the operating state of the power converter is determined using the current measurement result of the power generation unit, and the abnormality determination is performed using the current measurement result of the power generation unit. be able to. Thereby, the abnormality in the photovoltaic power generation system can be satisfactorily determined. Therefore, it is possible to improve the abnormality determination of the photovoltaic power generation system.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals and the description thereof will not be repeated. In addition, at least a part of the embodiments described below may be arbitrarily combined.

[Configuration of photovoltaic power generation system]
FIG. 1 is a diagram showing a configuration of a photovoltaic power generation system according to an embodiment of the present invention.

With reference to FIG. 1, the photovoltaic power generation system 401 includes four PCS (Power Conditioning Subsystem) units 80 and a cubicle 6. The cubicle 6 includes a copper bar 73.

Although four PCS units 80 are typically shown in FIG. 1, a large number or a small number of PCS units 80 may be provided.

FIG. 2 is a diagram showing a configuration of a PCS unit according to an embodiment of the present invention.

With reference to FIG. 2, the PCS unit 80 includes four current collector units 60 and a PCS (power conversion device) 8. The PCS 8 includes a copper bar 7 and a power conversion unit 9.

Although four current collecting units 60 are typically shown in FIG. 2, a large number or a small number of current collecting units 60 may be provided.

FIG. 3 is a diagram showing a configuration of a current collector unit according to an embodiment of the present invention.

With reference to FIG. 3, the current collector unit 60 includes four solar cell units 74 and a current collector box 71. The current collector box 71 has a copper bar 72.

Although the four solar cell units 74 are typically shown in FIG. 3, a larger number or a smaller number of solar cell units 74 may be provided.

FIG. 4 is a diagram showing a configuration of a solar cell unit according to an embodiment of the present invention.

With reference to FIG. 4, the solar cell unit 74 includes four power generation units 78A, 78B, 78C, 78D and a junction box 76. The power generation unit 78 has a solar cell panel 79. The junction box 76 has a copper bar 77. Hereinafter, each of the power generation units 78A, 78B, 78C, and 78D will also be referred to as a power generation unit 78.

Although four power generation units 78 are typically shown in FIG. 4, a large number or a small number of power generation units 78 may be provided.

The power generation unit 78 is a string in which four solar cell panels 79 are connected in series in this example.

Although the four solar cell panels 79 are typically shown in FIG. 4, a larger number or a smaller number of solar cell panels may be provided.

In the photovoltaic power generation system 401, the output lines and the aggregation lines, that is, the power lines from the plurality of power generation units 78 are electrically connected to the cubicle 6, respectively.

More specifically, the output line 1 of the power generation unit 78 has a first end connected to the power generation unit 78 and a second end connected to the copper bar 77. Each output line 1 is aggregated into the aggregation line 5 via the copper bar 77. The copper bar 77 is provided inside, for example, the junction box 76.

When the power generation unit 78 receives sunlight, it converts the energy of the received sunlight into DC power and outputs the converted DC power to the output line 1.

With reference to FIGS. 3 and 4, the aggregation line 5 has a first end connected to the copper bar 77 in the corresponding solar cell unit 74 and a second end connected to the copper bar 72. Each aggregation line 5 is aggregated into the aggregation line 2 via the copper bar 72. The copper bar 72 is provided inside, for example, the current collector box 71.

With reference to FIGS. 1 to 4, in the photovoltaic power generation system 401, as described above, each output line 1 from the plurality of power generation units 78 is aggregated in the aggregation line 5, and each aggregation line 5 is aggregated in the aggregation line 2. Then, each aggregation line 2 is aggregated into the aggregation line 4, and each aggregation line 4 is electrically connected to the cubicle 6.

More specifically, each aggregation line 2 has a first end connected to a copper bar 72 in the corresponding current collecting unit 60 and a second end connected to the copper bar 7. In the PCS 8, the internal line 3 has a first end connected to the copper bar 7 and a second end connected to the power converter 9.

In the PCS8, for example, the power conversion unit 9 transmits the DC power generated by each power generation unit 78 via the output line 1, the copper bar 77, the aggregation line 5, the copper bar 72, the aggregation line 2, the copper bar 7, and the internal line 3. When it is received at, the received DC power is converted into AC power and output to the aggregation line 4.

The aggregation line 4 has a first end connected to the power conversion unit 9 and a second end connected to the copper bar 73.

In the cubicle 6, the AC power output from the power conversion unit 9 in each PCS 8 to each aggregation line 4 is output to the system via the copper bar 73.

[Configuration of power generation status determination system 301]
FIG. 5 is a diagram showing a configuration of a power generation state determination system according to an embodiment of the present invention.

With reference to FIG. 5, the photovoltaic power generation system 401 includes a power generation state determination system 301. The power generation state determination system 301 includes a management device 101, a plurality of monitoring devices 111, and a collection device 151.

Although FIG. 5 typically shows four monitoring devices 111 provided corresponding to one current collecting unit 60, a larger number or a smaller number of monitoring devices 111 may be provided. Further, although the power generation state determination system 301 includes one collecting device 151, a plurality of collecting devices 151 may be provided.

In the power generation state determination system 301, the information of the sensor in the monitoring device 111, which is a slave unit, is transmitted to the collecting device 151 periodically or irregularly.

The monitoring device 111 is provided in, for example, the current collecting unit 60. More specifically, four monitoring devices 111 are provided corresponding to each of the four solar cell units 74. Each monitoring device 111 is electrically connected to, for example, the corresponding output line 1 and aggregation line 5.

The monitoring device 111 measures the current of each output line 1 in the corresponding solar cell unit 74 by a sensor. Further, the monitoring device 111 measures the voltage of each output line 1 in the corresponding solar cell unit 74 by a sensor.

The collection device 151 collects the measurement results of each monitoring device 111. The collection device 151 is provided, for example, in the vicinity of the PCS 8. More specifically, the collecting device 151 is provided corresponding to the PCS 8 and is electrically connected to the copper bar 7 via the signal line 46.

The monitoring device 111 and the collecting device 151 transmit and receive information by performing power line communication (PLC) via the aggregation lines 2 and 5.

More specifically, each monitoring device 111 transmits the current and voltage measurement results of the corresponding output lines, and monitoring information indicating the abnormality determination result.

The collection device 151 can transmit and receive information via the aggregation lines 2 and 5. Specifically, the collecting device 151 performs power line communication with the monitoring device 111 via the signal line 46 and the aggregation lines 2 and 5, and receives the monitoring information from the monitoring device 111.

The collection device 151 transmits / receives information to / from other devices such as the management device 101 via the network.

[Configuration of monitoring device 111]
FIG. 6 is a diagram showing a configuration of a monitoring device in the power generation state determination system according to the embodiment of the present invention. In FIG. 6, the inside of the junction box 76 is shown in more detail.

With reference to FIG. 6, the junction box 76 includes an aggregation unit 91, switches 93A, 93B, 93C, 93D, backflow prevention diodes 94A, 94B, 94C, 94D, output line 1, aggregation line 5, and so on. Includes copper bar 77.

Hereinafter, each of the switches 93A, 93B, 93C, and 93D is also referred to as a switch 93, and each of the backflow prevention diodes 94A, 94B, 94C, and 94D is also referred to as a backflow prevention diode 94.

Each of the output lines 1 includes plus side output lines 1pa, 1pb, 1pc and minus side output lines 1na, 1nb.

The aggregation line 5 includes a plus side aggregation line 5p and a minus side aggregation line 5n. The aggregation unit 91 includes the copper bar 77 and aggregates the output lines 1 from the plurality of power generation units 78. The copper bar 77 has a positive side copper bar 77p and a negative side copper bar 77n.

Although not shown, the copper bar 72 in the current collector box 71 shown in FIG. 3 includes a plus side copper bar 72p and a minus side copper bar 72n corresponding to the plus side aggregation line 5p and the minus side aggregation line 5n, respectively.

The backflow prevention diode 94 is connected between the power generation unit 78 and the aggregation unit 91.

More specifically, the positive output line 1pa has a first end connected to the corresponding power generation unit 78 and a second end connected to the corresponding switch 93. The positive output line 1pb has a first end connected to the corresponding switch 93 and a second end connected to the anode of the corresponding backflow prevention diode 94. The positive output line 1pc has a first end connected to the cathode of the corresponding backflow prevention diode 94 and a second end connected to the corresponding positive copper bar 77p.

The negative output line 1na has a first end connected to the corresponding power generation unit 78 and a second end connected to the corresponding switch 93. The negative output line 1nb has a first end connected to the corresponding switch 93 and a second end connected to the negative copper bar 77n.

The positive-side aggregation line 5p has a first end connected to the positive-side copper bar 77p and a second end connected to the positive-side copper bar 72p in the current collector box 71. The minus side aggregation line 5n has a first end connected to the minus side copper bar 77n and a second end connected to the minus side copper bar 72n in the current collector box 71.

The monitoring device 111 includes an acquisition unit 11, a communication unit 14, a determination unit 15, a voltage sensor 17, a storage unit 18, and a measurement unit 19. The measuring unit 19 includes four current sensors 16. The monitoring device 111 may further include a large number or a small number of current sensors 16 depending on the number of output lines 1.

The monitoring device 111 is provided, for example, in the vicinity of the power generation unit 78. Specifically, the monitoring device 111 is provided inside, for example, a junction box 76 provided with a copper bar 77 to which the output line 1 to be measured is connected. The monitoring device 111 may be provided outside the junction box 76.

The monitoring device 111 is electrically connected to, for example, the plus side aggregation line 5p and the minus side aggregation line 5n via the plus side power supply line 26p and the minus side power supply line 26n, respectively. Hereinafter, each of the positive power supply line 26p and the negative power supply line 26n is also referred to as a power supply line 26.

The acquisition unit 11 acquires the current measurement result of the power generation unit 78. More specifically, the acquisition unit 11 acquires a measurement result indicating the current of the output line 1 measured by the current sensor 16.

Specifically, the current sensor 16 is, for example, a Hall element type current probe. The current sensor 16 is connected between the power generation unit 78 and the PCS8, and uses the power received from a power supply circuit (not shown) of the monitoring device 111 to draw a current flowing through the corresponding positive output line 1p, for example, at predetermined time intervals. The measurement is performed, and a signal indicating the measurement result is output to the acquisition unit 11. The current sensor 16 may measure the current flowing through the negative output line 1n.

The voltage sensor 17 measures the voltage of the output line 1 at predetermined time intervals, for example. More specifically, the voltage sensor 17 measures the voltage between the positive side copper bar 77p and the negative side copper bar 77n, and outputs a signal indicating the measurement result to the acquisition unit 11.

The acquisition unit 11 includes measurement results included in each signal received from the current sensor 16 and the voltage sensor 17, an ID of the corresponding current sensor 16 (hereinafter, also referred to as a current sensor ID), and an ID of the voltage sensor 17 (hereinafter, also referred to as an ID). The voltage sensor ID) is stored in the storage unit 18.

The determination unit 15 determines the operating state of the PCS 8 based on the measurement result of the power generation unit 78, and determines the abnormality based on the determined operating state and the measurement result of the power generation unit 78.

For example, the determination unit 15 determines an abnormality based on the measurement result of the current of the power generation unit 78 in the stopped state of the PCS 8.

[Abnormality judgment 1]
The determination unit 15 determines, for example, an abnormality in the circuit between the measurement unit 19 and the PCS 8 based on the measurement result indicating the output current of the power generation unit 78.

Specifically, the determination unit 15 acquires, for example, each measurement result of the current sensor 16 having the same current sensor ID from the storage unit 18 every day, and arranges the acquired measurement results in chronological order. Create string current data.

FIG. 7 is a diagram showing an example of normal string current data in the power generation state determination system according to the embodiment of the present invention. In FIG. 7, the horizontal axis represents time, and the vertical axis represents the measurement result of the current sensor 16, that is, the current value.

With reference to FIG. 7, in the output line 1, no current flows until time t1, current flows according to the generated power in the corresponding power generation unit 78 from time t1 to time t2 in the evening, and current flows after time t2. Does not flow.

The PCS 8 operates by, for example, the electric power generated by the power generation unit 78. The monitoring device 111 determines whether the PCS 8 is in the operating state or the stopped state from the measurement results included in the signals received from each of the current sensor 16 and the voltage sensor 17.

More specifically, the determination unit 15 in the monitoring device 111 is electrically connected to the PCS 8 measured by the current sensor 16 and the voltage measured by the voltage sensor 17 is sufficient to operate the PCS 8. When the total current flowing through the output line 1 is sufficient to operate the PCS 8, it is determined that the PCS 8 is in the operating state.

Specifically, the determination unit 15 acquires the measurement results of the current sensor 16 and the voltage sensor 17 from the storage unit 18 every day, and arranges the acquired measurement results in chronological order.

Then, the determination unit 15 determines the operating state of the PCS 8 based on the measurement result of the power generation unit 78.

Specifically, the determination unit 15 determines from the measurement results arranged in time series that the operating state of the PCS 8 is the operating state in the time zone in which the voltage is equal to or higher than the predetermined value and the current is equal to or higher than the predetermined value. It is determined that the operating state of the PCS 8 is the stopped state in the time zone excluding the band.

In the example of FIG. 7, the determination unit 15 determines that the PCS 8 is in the operating state during the period from the time t1 to the time t2.

The PCS8 stops the power conversion until the time t1 in the morning because the power capable of operating the PCS8 is not supplied from the power generation unit 78.

At this time, since the PCS 8 has a high impedance, no current flows through the output line 1 electrically connected to the PCS 8.

From time t1 in the morning to time t2 in the evening, electric power capable of operating the PCS 8 is supplied from the power generation unit 78, so that a current flows through the output line 1.

After time t2 in the evening, the PCS8 stops the power conversion because the power capable of operating the PCS8 is not supplied from the power generation unit 78.

At this time, since the PCS 8 has a high impedance, no current flows through the output line 1 electrically connected to the PCS 8.

FIG. 8 is a diagram showing an example of a state in which the output line from the power generation unit in the photovoltaic power generation system according to the embodiment of the present invention is short-circuited between the positive and negative electrodes.

With reference to FIG. 8, for example, in the stopped state of PCS8 before time t1 in the morning and after time t2 in the evening, the plus side output line 1pb and the minus side output line 1nb are short-circuited between the current sensor 16 and the PCS8. In this case, the current I1 flows through the output line 1.

FIG. 9 is a diagram showing an example of string current data in an output line short-circuited between positive and negative electrodes in the power generation state determination system according to the embodiment of the present invention. In FIG. 9, the horizontal axis represents time, and the vertical axis represents the measurement result of the current sensor 16, that is, the current value.

With reference to FIG. 9, graph D1 is identical to the graph shown in FIG. 7 and shows an example of normal string current data. Graph D2 shows an example of string current data in an output line short-circuited between the positive and negative electrodes.

In the graph D2, the current flowing through the output line 1 can be confirmed before the time t1 and after the time t2.

In the determination unit 15, for example, when the current flowing through the output line 1 is equal to or higher than a predetermined value before the time t1 and after the time t2 when the PCS8 is stopped, the circuit between the measurement unit 19 including the current sensor 16 and the PCS8 is connected. Determined to be abnormal.

That is, the determination unit 15 can detect a short circuit between the positive and negative electrodes between the measurement unit 19 and the PCS 8.

The determination unit 15 outputs to the communication unit 14 the determination result indicating the abnormality of the circuit between the determination measurement unit 19 and the PCS8, the string current data, and the monitoring information associated with the measurement result of the voltage sensor 17.

The communication unit 14 can perform power line communication via the aggregation line with the collection device 151 that collects the measurement results of the plurality of monitoring devices 111. More specifically, the communication unit 14 can send and receive information via the aggregation lines 2 and 5. Specifically, the communication unit 14 performs power line communication with the collection device 151 via the power supply line 26 and the aggregation lines 2 and 5.

The communication unit 14 transmits the monitoring information received from the determination unit 15 to the collection device 151.

[Abnormality judgment 2]
The determination unit 15 determines, for example, an abnormality of the backflow prevention diode based on the measurement result indicating the backflow current to the power generation unit 78 in the stopped state of the PCS8.

FIG. 10 is a diagram showing a short-circuit failure of the backflow prevention diode in the power generation state determination system according to the embodiment of the present invention.

With reference to FIG. 10, for example, the backflow prevention diode 94A has a short-circuit failure, and the output voltage of the power generation unit 78A electrically connected to the failed backflow prevention diode 94 has shadows, dirt, parallel arcs, ground faults, and When the voltage is reduced due to factors such as initial failure, the output currents I2 of the other three power generation units 78B, 78C, and 78D flow into the power generation unit 78A.

FIG. 11 is a diagram showing an example of string current data of a power generation unit corresponding to a backflow prevention diode having a short-circuit failure in the power generation state determination system according to the embodiment of the present invention. In FIG. 11, the horizontal axis represents time, and the vertical axis represents the measurement result of the current sensor 16, that is, the current value.

With reference to FIG. 11, graph D3 shows string current data of power generation unit 78B, which is a normal power generation unit 78, and graph D4 shows power generation unit 78A, which is a power generation unit 78 corresponding to a short-circuit faulty backflow prevention diode. The string current data is shown.

In the current sensor 16 corresponding to the power generation unit 78B, for example, when the backflow prevention diode 94A corresponding to the power generation unit 78A fails due to a short circuit or the like and the voltage of the power generation unit 78A drops, the PCS8 is stopped, that is, at time t1. The output current of the power generation unit 78B is measured before and after time t2.

Further, in the current sensor 16 corresponding to the power generation unit 78A, a negative current value, that is, a reverse current to the power generation unit 78A is measured before the time t1 and after the time t2.

For example, when the reverse current flows through the output line 1 in the stopped state of the PCS 8, the determination unit 15 determines that the backflow prevention diode 94 corresponding to the output line 1 is abnormal.

That is, the determination unit 15 can detect a short-circuit failure of the backflow prevention diode 94.

The determination unit 15 outputs the determination result indicating the abnormality of the determined backflow prevention diode 94, the string current data, and the monitoring information associated with the measurement result of the voltage sensor 17 to the communication unit 14.

The communication unit 14 transmits the monitoring information received from the determination unit 15 to the collection device 151.

[Abnormality judgment 3]
The determination unit 15 determines, for example, an abnormality in the circuit between the power generation unit 78 and the measurement unit 19 based on the measurement result indicating the output current of the power generation unit 78 in the operating state of the PCS 8.

FIG. 12 is a diagram showing another example in which the output line from the power generation unit in the photovoltaic power generation system according to the embodiment of the present invention is short-circuited between the positive and negative electrodes.

With reference to FIG. 12, for example, when the plus side output line 1pb and the minus side output line 1nb are short-circuited between the power generation unit 78 and the measurement unit 19 in the operating state of the PCS8, the plus side output line 1pa to the plus side output The current flowing through the line 1pb is branched into a current I3a flowing through the short-circuited portion and a current I3b flowing through the aggregation unit 91. The current I3b is much smaller than the current I3a.

FIG. 13 is a diagram showing another example of string current data in an output line short-circuited between positive and negative electrodes in the power generation state determination system according to the embodiment of the present invention. In FIG. 13, the horizontal axis represents time, and the vertical axis represents the measurement result of the current sensor 16, that is, the current value.

As shown in the graph D5 with reference to FIG. 13, the current flowing through the output line 1 becomes smaller after the time t3 because the positive and negative electrodes of the output line are short-circuited at the time t3.

For example, when the current flowing through the output line 1 or the like is less than a predetermined value in at least a part of the period from the time t1 to the time t2 in which the PCS8 is in operation, the determination unit 15 is between the power generation unit 78 and the measurement unit 19. Judges that the circuit of is abnormal.

That is, the determination unit 15 can detect a short circuit between the positive and negative electrodes between the power generation unit 78 and the measurement unit 19.

The determination unit 15 outputs to the communication unit 14 the determination result indicating the abnormality of the circuit between the determined power generation unit 78 and the measurement unit 19, the string current data, and the monitoring information associated with the measurement result of the voltage sensor 17.

The communication unit 14 transmits the monitoring information received from the determination unit 15 to the collection device 151.

[Abnormality judgment 4]
The determination unit 15 determines, for example, an abnormality in the circuit between the measurement unit 19 and the aggregation unit 91 based on the measurement result indicating the output current of the power generation unit 78 in the operating state of the PCS 8.

With reference to FIG. 9 again, as shown in Graphs D1 and D2, the current flowing through the output line 1 short-circuited between the positive and negative electrodes during the operating state of PCS8, that is, the period from time t1 to time t2, is a normal output. It is larger than the current flowing through the line 1.

FIG. 14 is a diagram showing the relationship between the output current and the output voltage of the power generation unit in the power generation state determination system according to the embodiment of the present invention. In FIG. 14, the horizontal axis represents voltage and the vertical axis represents current.

With reference to FIG. 14, in the power generation unit 78, the current and the voltage are controlled so that the generated power is maximized by maximum power point tracking (MPPT: Maximum Power Point Tracking).

The point pm shown in FIG. 14 is the point where the generated power is maximized. At this time, the output voltage of the power generation unit 78 is Vpm, and the output current of the power generation unit 78 is Ipm.

In the power generation unit 78 in which the positive and negative electrodes are short-circuited, for example, the output voltage drops to Vsc. At this time, the output current at which the generated power is maximized is Isc, which is larger than Ipm. Therefore, as shown in Graphs D1 and D2 shown in FIG. 9, the current flowing through the output line 1 short-circuited between the positive and negative electrodes is larger than the current flowing through the normal output line 1.

For example, in the operating state of the PCS 8, the determination unit 15 compares the currents flowing through each output line 1, and the circuit corresponding to the output line 1 in which a current larger than the current flowing through the other output lines 1 is flowing is abnormal. Is determined.

More specifically, the determination unit 15 creates string current data for each power generation unit 78. Then, the determination unit 15 calculates the average value AVE of the current values of the power generation units 78 at the time t4 in the period from the time t1 to the time t2. The time t4 is, for example, the time when the output current of a certain power generation unit 78 becomes the maximum in a day.

When the current value of the power generation unit 78 at time t4 is larger than the average value AVE by a predetermined value or more, the determination unit 15 has an abnormality in the circuit between the measurement unit 19 and the aggregation unit 91 in the output line 1 corresponding to the power generation unit 78. Is determined.

That is, the determination unit 15 can detect a short circuit between the positive and negative electrodes between the measurement unit 19 and the aggregation unit 91.

The determination unit 15 outputs to the communication unit 14 the determination result indicating the abnormality of the circuit between the determination measurement unit 19 and the aggregation unit 91, the string current data, and the monitoring information associated with the measurement result of the voltage sensor 17.

The communication unit 14 transmits the monitoring information received from the determination unit 15 to the collection device 151.

[Operation flow]
Each device in the power generation state determination system 301 includes a computer, and an arithmetic processing unit such as a CPU in the computer reads and executes a program including a part or all of each step in the following flowchart from a memory (not shown). The programs of these plurality of devices can be installed from the outside. The programs of these plurality of devices are distributed in a state of being stored in a recording medium.

FIG. 15 is a flowchart defining an operation procedure when the monitoring device according to the embodiment of the present invention determines an abnormality.

With reference to FIG. 15, first, the monitoring device 111 acquires the measurement results of the current and voltage of the power generation units 78A, 78B, 78C, and 78D (step S101).

Next, the monitoring device 111 determines the operating state of the PCS 8 based on the acquired measurement result. More specifically, the monitoring device 111 determines the time zone in which the PCS 8 is in the operating state and the time zone in which it is in the stopped state based on the acquired measurement result (step S102).

Next, the monitoring device 111 creates string current data for each power generation unit 78 from the acquired measurement results (step S103).

Next, the monitoring device 111 makes an abnormality determination based on the measurement result in the time zone when the PCS 8 is stopped (step S104).

Next, the monitoring device 111 makes an abnormality determination based on the measurement result in the time zone when the PCS 8 is in the operating state (step S105).

Next, the monitoring device 111 acquires new measurement results of the current and voltage of the power generation units 78A, 78B, 78C, and 78D (step S101).

The order of steps S102 and S103 is not limited to the above, and the order may be changed.

Further, the order of steps S104 and S105 is not limited to the above, and the order may be changed.

FIG. 16 is a flowchart defining an operation procedure when the monitoring device according to the embodiment of the present invention determines an abnormality in a stopped state of the PCS.

With reference to FIG. 16, first, the monitoring device 111 starts the abnormality determination for a certain power generation unit 78. When the reverse current is measured in the stopped state of the PCS 8 (YES in step S201), the monitoring device 111 determines that the short-circuit failure of the backflow prevention diode 94 in the corresponding output line 1 is abnormal (step S202).

Next, the monitoring device 111 transmits the monitoring information including the determination result, the string current data, and the measurement result of the voltage sensor 17 to the collecting device 151 (step S203).

On the other hand, when the output current of a predetermined value or more is measured in the stopped state of the PCS 8 (NO in step S201 and YES in step S204), the monitoring device 111 has the measuring unit 19 and the aggregation unit of the corresponding output lines 1. It is determined that there is an abnormality in the short circuit between the positive and negative electrodes between 91 (step S205).

Next, the monitoring device 111 transmits the monitoring information including the determination result, the string current data, and the measurement result of the voltage sensor 17 to the collecting device 151 (step S203).

On the other hand, when the reverse current is not measured (NO in step S201) and the current less than a predetermined value is measured in the stopped state of PCS8 (NO in step S204), the monitoring device 111 corresponds to the circuit of the output line 1. Is normal (step S206).

Next, the monitoring device 111 transmits the monitoring information including the determination result, the string current data, and the measurement result of the voltage sensor 17 to the collecting device 151 (step S203).

Next, when the monitoring device 111 has not made an abnormality determination on the measurement result of the other power generation unit 78 (NO in step S207), the monitoring device 111 makes an abnormality determination on the measurement result of the other power generation unit 78 (step S201).

On the other hand, when the monitoring device 111 determines the abnormality for the measurement results of all the power generation units 78 (YES in step S207), the monitoring device 111 ends the abnormality determination in the stopped state of the PCS.

FIG. 17 is a flowchart defining an operation procedure when the monitoring device according to the embodiment of the present invention determines an abnormality in the operating state of the PCS.

With reference to FIG. 17, first, the monitoring device 111 starts the abnormality determination for a certain power generation unit 78. When the output current less than a predetermined value is measured in the operating state of the PCS 8 (YES in step S301), the monitoring device 111 has an abnormality of a short circuit between the positive and negative electrodes between the power generation unit 78 and the measurement unit 19 in the corresponding output line 1. (Step S302).

Next, the monitoring device 111 transmits the monitoring information including the determination result, the string current data, and the measurement result of the voltage sensor 17 to the collecting device 151 (step S303).

On the other hand, when the monitoring device 111 measures an output current of a predetermined value or more (NO in step S301) and an output current larger than a predetermined value is measured in the operating state of the PCS 8 as compared with other string current data. (YES in step S304), it is determined that there is an abnormality of a short circuit between the positive and negative electrodes between the measurement unit 19 and the aggregation unit 91 in the corresponding output line 1 (step S305).

Next, the monitoring device 111 transmits the monitoring information including the determination result, the string current data, and the measurement result of the voltage sensor 17 to the collecting device 151 (step S303).

On the other hand, when the monitoring device 111 measures a current equal to or higher than a predetermined output value (NO in step S301) and an output current smaller than a predetermined value is measured as compared with other string current data in the operating state of the PCS8. (NO in step S304), it is determined that the circuit of the corresponding output line 1 is normal (step S306).

Next, the monitoring device 111 transmits the monitoring information including the determination result, the string current data, and the measurement result of the voltage sensor 17 to the collecting device 151 (step S303).

Next, when the monitoring device 111 has not made an abnormality determination on the measurement result of the other power generation unit 78 (NO in step S307), the monitoring device 111 makes an abnormality determination on the measurement result of the other power generation unit 78 (step S301).

On the other hand, when the monitoring device 111 makes an abnormality determination on the measurement results of all the power generation units 78 (YES in step S307), the monitoring device 111 ends the abnormality determination in the operating state of the PCS.

In the power generation state determination system according to the embodiment of the present invention, the PCS 8 is configured to stop the power conversion when the operable power is not supplied from the power generation unit 78, but the present invention is not limited to this. Absent. The PCS8 may be configured to stop the power conversion, for example, when the power generation unit 78 is generating power exceeding the PCS8 conversion capacity, or when the output to the system is suppressed.

Further, in the power generation state determination system according to the embodiment of the present invention, the monitoring device 111 is configured to determine an abnormality, but the present invention is not limited to this. The monitoring device 111 transmits each measurement result, the current sensor ID and the voltage sensor ID to the collecting device 151 or the management device 101, and the collecting device 151 or the management device 101 is based on each measurement result transmitted from the monitoring device 111. , It may be configured to determine an abnormality. In this case, the management device 101 includes an acquisition unit that acquires each measurement result transmitted from the monitoring device 111, and a determination unit that performs abnormality determinations 1 to 4 based on each measurement result acquired by the acquisition unit.

Further, in the power generation state determination system according to the embodiment of the present invention, the monitoring device 111 is configured to perform abnormality determinations 1 to 4, but the present invention is not limited to this. The monitoring device 111 may be configured to perform a part of the abnormality determinations 1 to 4.

Further, in the power generation state determination system according to the embodiment of the present invention, the monitoring device 111 is configured to include the measuring unit 19, but the present invention is not limited to this. The measurement unit 19 may be configured to be provided outside the monitoring device 111.

Further, in the photovoltaic power generation system according to the embodiment of the present invention, the backflow prevention diode 94 is provided for each power generation unit 78, but the present invention is not limited to this. In the photovoltaic power generation system 401, a part or all of the backflow prevention diodes 94A, 94B, 94C, 94D may not be provided.

Further, in the power generation state determination system according to the embodiment of the present invention, the current sensor 16 is provided for each power generation unit 78, but the present invention is not limited to this. The power generation state determination system 301 may be configured such that a part of the current sensors 16 is not provided. However, the monitoring device 111 performs the abnormality determination 4 when a plurality of current sensors 16 are provided in the corresponding power generation units 78.

By the way, a technique capable of improving the abnormality determination of the photovoltaic power generation system beyond the technique described in Patent Document 1 is desired.

In the monitoring device according to the embodiment of the present invention, the acquisition unit 11 acquires the current measurement result of the power generation unit 78 including the solar cell panel 79. The determination unit 15 determines the operating state of the PCS 8 based on the measurement result, and determines the abnormality based on the determined operating state and the measurement result.

With such a configuration, the operating state of the PCS 8 is discriminated by using the current measurement result of the power generation unit 78, and the abnormality judgment is performed by using the current measurement result of the power generation unit 78. be able to. As a result, the abnormality in the photovoltaic power generation system 401 can be satisfactorily determined.

Therefore, in the monitoring device according to the embodiment of the present invention, it is possible to improve the abnormality determination of the photovoltaic power generation system 401.

Further, in the monitoring device according to the embodiment of the present invention, the determination unit 15 determines that the operating state of the PCS 8 is the stopped state, and determines an abnormality based on the measurement result in the stopped state.

In this way, by paying attention to the measurement result of the current of the power generation unit 78 in the stopped state of the PCS8 and determining the abnormality using the measurement result of the output current of the power generation unit 78, the abnormality in the photovoltaic power generation system 401 is satisfactorily determined. It can be determined.

Further, in the power generation state determination system according to the embodiment of the present invention, the measurement unit 19 for measuring the current of the power generation unit 78 is connected between the power generation unit 78 and the PCS 8, and in the monitoring device 111, the determination unit 15 is Based on the measurement result indicating the output current of the power generation unit 78, the abnormality of the circuit between the measurement unit 19 and the PCS 8 is determined.

With such a configuration, the abnormality of the circuit between the measuring unit 19 and the PCS 8 can be satisfactorily determined by using the measurement result of the output current of the power generation unit 78.

Further, in the power generation state determination system according to the embodiment of the present invention, in the photovoltaic power generation system 401, the output lines from the plurality of power generation units 78 are aggregated in the aggregation unit 91 and electrically connected to the PCS 8 to prevent backflow. The diode 94 is connected between a part or all of the power generation units 78 and the aggregation unit 91 of the plurality of power generation units 78, and the measurement unit 19 that measures the current of the corresponding power generation unit 78 is a part of the measurement unit 19. Alternatively, it is connected between all the power generation units 78 and the corresponding backflow prevention diode 94, and in the monitoring device 111, the determination unit 15 is based on the measurement result indicating the backflow current to the partial or all power generation units 78. , The abnormality of the backflow prevention diode 94 is determined.

With such a configuration, the abnormality of the backflow prevention diode 94 can be satisfactorily determined by using the measurement result of the backflow current to the power generation unit 78.

Further, in the power generation state determination system according to the embodiment of the present invention, the measurement unit 19 for measuring the current of the power generation unit 78 is connected between the power generation unit 78 and the PCS 8, and in the monitoring device 111, the determination unit 15 is , The operating state of the PCS 8 is determined to be the operating state, and an abnormality in the circuit between the power generation unit 78 and the measuring unit 19 is determined based on the measurement result indicating the output current of the power generation unit 78 in the operating state of the PCS 8.

In this way, the circuit between the power generation unit 78 and the measurement unit 19 is configured to focus on the current measurement result of the power generation unit 78 in the operating state of the PCS 8 and determine an abnormality using the measurement result of the output current of the power generation unit 78. It is possible to judge the abnormality of.

Further, in the power generation state determination system according to the embodiment of the present invention, in the photovoltaic power generation system 401, the output lines from the plurality of power generation units 78 are aggregated in the aggregation unit 91 and electrically connected to the PCS 8 to correspond. The measuring unit 19 for measuring the current of the power generation unit 78 of the above is connected between the plurality of power generation units 78 of some or all of the plurality of power generation units 78 and the PCS8, and in the monitoring device 111, the determination unit 15 is , The abnormality of the circuit between the measurement unit 19 and the aggregation unit 91 is determined based on the measurement result indicating the output currents of the plurality of power generation units 78 in the operating state of the PCS 8.

In this way, paying attention to the current measurement result of the power generation unit 78 in the operating state of the PCS 8, the abnormality is determined by using the measurement result of the output current of each power generation unit 78, and the measurement unit 19 and the aggregation unit 91 are connected to each other. The abnormality of the circuit can be judged well.

Further, in the determination method in the monitoring device according to the embodiment of the present invention, first, the measurement result of the current of the power generation unit 78 is acquired. Next, the operating state of the PCS 8 is determined based on the measurement result. Next, the abnormality is determined based on the determined operating state and the measurement result.

With such a configuration, the operating state of the PCS 8 is discriminated by using the current measurement result of the power generation unit 78, and the abnormality judgment is performed by using the current measurement result of the power generation unit 78. be able to. As a result, the abnormality in the photovoltaic power generation system 401 can be satisfactorily determined.

Therefore, the determination method in the monitoring device according to the embodiment of the present invention can improve the abnormality determination of the photovoltaic power generation system 401.

It should be considered that the above embodiments are exemplary in all respects and not restrictive. The scope of the present invention is shown by the claims rather than the above description, and it is intended to include all modifications within the meaning and scope equivalent to the claims.

The above description includes the features described below.
[Appendix 1]
A monitoring device used in a photovoltaic power generation system in which the output line from the power generation unit including the solar cell panel is electrically connected to the power conversion device.
An acquisition unit that acquires the current measurement result of the power generation unit, and
It is provided with a determination unit for determining an abnormality based on the measurement result in the stopped state of the power conversion device.
The power generation unit is a monitoring device in which a plurality of solar cell panels are connected in series.

1 Output line 2, 4, 5 Aggregate line 3 Internal line 6 Cubicles 7 Copper bar 8 PCS
9 Power conversion unit 11 Acquisition unit 14 Communication unit 15 Judgment unit 16 Current sensor 17 Voltage sensor 18 Storage unit 19 Measurement unit 26 Power supply line 46 Signal line 60 Current collection unit 71 Current collection box 72, 73, 77 Copper bar 74 Solar cell unit 76 Junction box 78 Power generation unit 79 Solar cell panel 80 PCS unit 81 Judgment unit 84 Communication processing unit 85 Storage unit 86 Acquisition unit 91 Aggregation unit 92 Measurement unit 93 Switch 94 Backflow prevention diode 101 Management device 111 Monitoring device 151 Collection device 301 Power generation Status judgment system 401 Solar power generation system

Claims (7)

A monitoring device used in a photovoltaic power generation system in which the output line from the power generation unit including the solar cell panel is electrically connected to the power conversion device.
An acquisition unit that acquires the current measurement result of the power generation unit, and
A monitoring device including a determination unit that determines the operating state of the power conversion device based on the measurement result, determines the operating state, and determines an abnormality based on the measurement result. The monitoring device according to claim 1, wherein the determination unit determines that the operating state of the power conversion device is in a stopped state, and determines an abnormality based on the measurement result in the stopped state. A measuring unit that measures the current of the power generation unit is connected between the power generation unit and the power conversion device.
The monitoring device according to claim 2, wherein the determination unit determines an abnormality in a circuit between the measurement unit and the power conversion device based on the measurement result indicating the output current of the power generation unit. In the photovoltaic power generation system, a plurality of output lines from the power generation unit are aggregated in the aggregation unit and electrically connected to the power conversion device.
A backflow prevention diode is connected between the power generation unit and the aggregation unit of a part or all of the plurality of power generation units.
A measuring unit that measures the current of the corresponding power generation unit is connected between the partial or all power generation unit and the corresponding backflow prevention diode.
The monitoring device according to claim 2 or 3, wherein the determination unit determines an abnormality of the backflow prevention diode based on the measurement result indicating a backflow current to a part or all of the power generation units. A measuring unit that measures the current of the power generation unit is connected between the power generation unit and the power conversion device.
The determination unit determines that the operating state of the power conversion device is an operating state, and the power generation unit and the measurement are based on the measurement result indicating the output current of the power generation unit in the operating state of the power conversion device. The monitoring device according to claim 1, wherein an abnormality of a circuit between units is determined. In the photovoltaic power generation system, a plurality of output lines from the power generation unit are aggregated in the aggregation unit and electrically connected to the power conversion device.
A measuring unit that measures the current of the corresponding power generation unit is connected between the power conversion device and a part or all of the power generation units of the plurality of power generation units.
The determination unit determines an abnormality in the circuit between the measurement unit and the aggregation unit based on the measurement result indicating the output currents of the partial or all of the plurality of power generation units in the operating state of the power conversion device. , The monitoring device according to claim 5. It is a judgment method in a monitoring device used in a photovoltaic power generation system in which an output line from a power generation unit including a solar cell panel is electrically connected to a power conversion device.
The step of acquiring the current measurement result of the power generation unit and
A step of determining the operating state of the power conversion device based on the measurement result, and
A determination method including the determined operating state and a step of determining an abnormality based on the measurement result.

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