Determination device, determination method, and determination program

Abstract

To easily detect the occurrence of an open circuit fault in a bypass diode.SOLUTION: In a determination device used in a solar power generation system equipped with a power generation unit including a solar cell panel, the solar cell panel is a cluster having a series circuit of solar cells, and includes a plurality of clusters being capable of bypassing the series circuit via a bypass diode, and the determination device includes an acquisition unit that acquires measurement results of an output of the power generation unit, and a determination unit that performs a fault determination process regarding an open fault of the bypass diode on the basis of the measurement results acquired by the acquisition unit, and in the fault determination process, when a first statistical value of the output during a first time period of a day is less than a predetermined first threshold value, the determination unit makes a positive determination regarding the occurrence of the open fault.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present disclosure relates to a determination device, a determination method, and a determination program. [Background technology]

[0002] Conventionally, solar cell panels including a plurality of solar cell cells connected in series and bypass diodes that bypass the current flowing through the plurality of solar cell cells have been developed. For example, Patent Document 1 (JP Patent Publication No. 2013-120802) discloses the following solar power generation device. That is, the solar power generation device is a solar cell string including a plurality of solar cell modules connected in series, characterized in that the solar power generation device includes a plurality of bypass diodes that are connected in parallel to each of the solar cell modules or a plurality of solar cell clusters that constitute each of the solar cell modules, respectively, and form a bypass path when the power generated from the solar cell module or the solar cell cluster decreases, and a notification means that detects and notifies the current-carrying state of each of the bypass diodes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-120802 A Summary of the Invention [Problem to be solved by the invention]

[0004] If an open circuit failure occurs in the bypass diode, the current flowing through the solar cell is not bypassed by the bypass diode, which may result in abnormal heat generation in the solar cell.

[0005] Conventionally, in order to detect the occurrence of an open circuit fault in a bypass diode, for example, it was necessary to inspect each solar cell panel in a photovoltaic power generation system using a dedicated measuring device. A technology that can easily detect the occurrence of an open circuit fault in a bypass diode is desired.

[0006] The present disclosure has been made to solve the above-mentioned problems, and has an object to provide a determination device, a determination method, and a determination program that are capable of easily detecting the occurrence of an open fault in a bypass diode. [Means for solving the problem]

[0007] The determination device disclosed herein is a determination device used in a solar power generation system equipped with a power generation unit including a solar panel, the solar panel being a cluster having a series circuit of solar cells, the cluster including a plurality of the clusters being capable of bypassing the series circuit via bypass diodes, the determination device including an acquisition unit that acquires measurement results of the output of the power generation unit, and a determination unit that performs fault determination processing regarding an open fault of the bypass diode based on the measurement results acquired by the acquisition unit, and the determination unit makes a positive determination of the occurrence of the open fault when a first statistical value of the output during a first time period of a day is less than a predetermined first threshold value in the fault determination processing.

[0008] One aspect of the present disclosure can be realized not only as a determination device having such a characteristic processing unit, but also as a semiconductor integrated circuit that realizes part or all of the determination device, or as a system that includes the determination device. Effect of the Invention

[0009] According to the present disclosure, the occurrence of an open circuit failure in a bypass diode can be easily detected. [Brief description of the drawings]

[0010] [Figure 1]FIG. 1 is a diagram showing a configuration of a solar power generation system according to a first embodiment of the present disclosure. [Diagram 2] FIG. 2 is a diagram illustrating a configuration of a PCS unit according to the first embodiment of the present disclosure. [Diagram 3] FIG. 3 is a diagram illustrating a configuration of a current collecting unit according to the first embodiment of the present disclosure. [Figure 4] FIG. 4 is a diagram illustrating a configuration of a solar cell unit according to the first embodiment of the present disclosure. [Diagram 5] FIG. 5 is a diagram showing a configuration of a solar cell panel according to the first embodiment of the present disclosure. [Figure 6] FIG. 6 is a diagram illustrating a configuration of a determination system according to the first embodiment of the present disclosure. [Figure 7] FIG. 7 is a diagram illustrating a configuration of a monitoring device in the determination system according to the first embodiment of the present disclosure. [Figure 8] FIG. 8 is a diagram illustrating a configuration of a determination device according to the first embodiment of the present disclosure. [Figure 9] FIG. 9 is a diagram for explaining the shadow determination process and the failure determination process performed by the determination device according to the first embodiment of the present disclosure. [Figure 10] FIG. 10 is a flowchart defining an operation procedure when the determination device according to the first embodiment of the present disclosure performs the shadow determination process and the failure determination process. [Figure 11] FIG. 11 is a diagram for explaining the shadow determination process and the failure determination process performed by the determination device according to the second embodiment of the present disclosure. [Figure 12] FIG. 12 is a flowchart defining an operation procedure when the determination device according to the second embodiment of the present disclosure performs the shadow determination process and the failure determination process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] First, the contents of the embodiments of the present disclosure will be listed and described. (1) A determination device according to an embodiment of the present disclosure is a determination device used in a solar power generation system having a power generation unit including a solar panel, the solar panel being a cluster having a series circuit of solar cells, the cluster including a plurality of the clusters being capable of bypassing the series circuit via bypass diodes, the determination device including: an acquisition unit that acquires measurement results of an output of the power generation unit; and a determination unit that performs a fault determination process regarding an open fault of the bypass diode based on the measurement results acquired by the acquisition unit, wherein in the fault determination process, when a first statistical value of the output during a first time period of a day is less than a predetermined first threshold value, the determination unit makes a positive determination regarding the occurrence of the open fault.

[0012] In a photovoltaic power generation system, when an open circuit failure occurs in a bypass diode, the output of the power generation unit during a certain time period of a day may be significantly reduced compared to when the bypass diode is normal. As described above, by focusing on the phenomenon that occurs when an open circuit failure occurs in a bypass diode and performing a determination regarding the occurrence of an open circuit failure, it is possible to detect a bypass diode that is likely to have an open circuit failure without using a dedicated measuring device. Therefore, it is possible to easily detect the occurrence of an open circuit failure in a bypass diode.

[0013] (2) In the above (1), the first threshold value may be a value that is equal to or lower than the output of the power generation unit operating in a state in which the open circuit fault does not occur and that is in a time period affected by shadow.

[0014] In a photovoltaic power generation system, when an open circuit failure occurs in a bypass diode, the output of the power generation unit during the time period of the day when it is affected by the shadow may be significantly reduced compared to when the bypass diode is normal. As described above, by setting a threshold value by focusing on the phenomenon that occurs when an open circuit failure occurs in a bypass diode, the threshold value can be set to an appropriate value, thereby improving the accuracy of detecting the occurrence of an open circuit failure.

[0015] (3) In the above (1) or (2), the judgment unit may make a positive judgment regarding the occurrence of an open fault when, in the fault judgment process, the first statistical value is less than the first threshold value and is greater than or equal to a predetermined second threshold value.

[0016] In a photovoltaic power generation system, when an open circuit failure occurs in a bypass diode, the output of the power generation unit during a certain time period of a day may be significantly reduced compared to when the bypass diode is normal. Furthermore, the minimum value of the output may be greater than the minimum value of the output of the power generation unit when another abnormality, such as a DC cable break, occurs. As described above, the accuracy of detecting the occurrence of an open circuit failure can be improved by focusing on the difference between the output when an open circuit failure occurs in the bypass diode and the output when another abnormality occurs.

[0017] (4) In any of (1) to (3) above, the judgment unit may make a positive judgment regarding the occurrence of an open circuit fault if, in the fault judgment process, the first statistical value is less than the first threshold value and a second statistical value of the output in a second time period of the day different from the first time period is greater than or equal to the first threshold value.

[0018] In a photovoltaic power generation system, if a first statistical value of the output of a power generation unit during a certain time period of a day is less than a first threshold value, and a second statistical value of the output of the power generation unit during another time period is less than a second threshold value, it is considered that another abnormality other than an open circuit failure of a bypass diode has occurred. As described above, by focusing on the difference between the phenomenon occurring when an open circuit failure occurs in a bypass diode and the phenomenon occurring when another abnormality occurs, the accuracy of detecting the occurrence of an open circuit failure can be improved.

[0019] (5) A determination device according to an embodiment of the present disclosure is a determination device used in a photovoltaic power generation system including a power generation unit including a solar cell panel, the solar cell panel being a cluster having a series circuit of solar cells, the cluster including a plurality of the clusters being capable of bypassing the series circuit via a bypass diode, the determination device including: an acquisition unit that acquires measurement results of an output of each of the power generation units; and a determination unit that performs a shadow determination process regarding an influence of a shadow on the power generation units based on the measurement results acquired by the acquisition unit, and when the determination unit makes a positive determination in the shadow determination process that there is an influence of the shadow on the plurality of the power generation units, based on the measurement results of the plurality of power generation units for which the positive judgment was made, a fault judgment process is performed regarding an open fault of the bypass diode, and when, in the fault judgment process, a relationship between a first statistical value of the output for a day of a first power generation unit, which is at least one of the plurality of power generation units for which the positive judgment was made, and a second statistical value of the output for a day of a second power generation unit, which is another power generation unit different from the first power generation unit among the plurality of power generation units for which the positive judgment was made, satisfies a predetermined condition, the judgment unit makes a positive judgment regarding the occurrence of an open fault of the bypass diode included in the solar panel of the first power generation unit.

[0020] In a photovoltaic power generation system, the output of a power generation unit in which an open circuit failure has occurred in a bypass diode and which is affected by a shadow may be significantly reduced compared to the output of other power generation units in which the bypass diode is normal and which are affected by a shadow. As described above, by focusing on the difference in the output of the power generation unit depending on whether or not an open circuit failure has occurred in the bypass diode and making a determination regarding the occurrence of an open circuit failure, it is possible to detect a bypass diode that is likely to have an open circuit failure without using a dedicated measuring device. Therefore, it is possible to easily detect the occurrence of an open circuit failure in a bypass diode.

[0021] (6) A determination method according to an embodiment of the present disclosure is a determination method in a determination device used in a photovoltaic power generation system equipped with a power generation unit including a solar panel, the solar panel being a cluster having a series circuit of solar cells, the cluster including a plurality of the clusters being capable of bypassing the series circuit via bypass diodes, the method including the steps of acquiring measurement results of an output of the power generation unit, and performing a fault determination process for an open circuit fault of the bypass diode based on the acquired measurement results, wherein in the step of performing the fault determination process, if a first statistical value of the output during a first time period of a day is less than a predetermined first threshold value, a positive determination is made as to the occurrence of the open circuit fault.

[0022] In a photovoltaic power generation system, when an open circuit failure occurs in a bypass diode, the output of the power generation unit during a certain time period of a day may be significantly reduced compared to when the bypass diode is normal. As described above, by focusing on the phenomenon that occurs when an open circuit failure occurs in a bypass diode and using a method for determining the occurrence of an open circuit failure, it is possible to detect bypass diodes that are likely to have an open circuit failure without using a dedicated measuring device. Therefore, it is possible to easily detect the occurrence of an open circuit failure in a bypass diode.

[0023] (7) A determination method according to an embodiment of the present disclosure is a determination method in a determination device used in a solar power generation system including a power generation unit including a solar panel, the solar panel being a cluster having a series circuit of solar cells, the solar panel including a plurality of the clusters being capable of bypassing the series circuit via a bypass diode, the method including the steps of: acquiring measurement results of an output of each of the power generation units; performing a shadow determination process regarding an influence of a shadow on the power generation units based on the acquired measurement results; and if a positive determination is made regarding the influence of the shadow on the plurality of the power generation units, performing a fault determination process regarding an open fault of the bypass diode based on the measurement results of the plurality of the power generation units for which the positive determination is made, wherein if a relationship between a first statistical value of the output for a day of a first power generation unit which is at least any one of the plurality of power generation units for which the positive determination is made and a second statistical value of the output for the day of a second power generation unit which is another of the plurality of power generation units for which the positive determination is made satisfies a predetermined condition, in the fault determination process performing a positive determination of the occurrence of the open fault of the bypass diode included in the solar panel of the first power generation unit.

[0024] In a photovoltaic power generation system, the output of a power generation unit in which an open circuit failure has occurred in a bypass diode and which is affected by a shadow may be significantly reduced compared to the output of other power generation units in which the bypass diode is normal and which are affected by a shadow. As described above, by focusing on the difference in the output of the power generation unit depending on whether or not an open circuit failure has occurred in the bypass diode and using a method for determining the occurrence of an open circuit failure, it is possible to detect a bypass diode that is likely to have an open circuit failure without using a dedicated measuring device. Therefore, it is possible to easily detect the occurrence of an open circuit failure in a bypass diode.

[0025] (8) A judgment program according to an embodiment of the present disclosure is a judgment program used in a judgment device used in a solar power generation system having a power generation unit including a solar panel, the solar panel being a cluster having a series circuit of solar cells, the solar panel including a plurality of the clusters being capable of bypassing the series circuit via bypass diodes, the judgment program causing a computer to function as an acquisition unit that acquires measurement results of the output of the power generation unit, and a judgment unit that performs fault judgment processing regarding an open fault of the bypass diode based on the measurement results acquired by the acquisition unit, and in the fault judgment processing, the judgment unit makes a positive judgment regarding the occurrence of the open fault when a first statistical value of the output in a first time period of a day is less than a predetermined first threshold value.

[0026] In a photovoltaic power generation system, when an open circuit failure occurs in a bypass diode, the output of the power generation unit during a certain time period of a day may be significantly reduced compared to when the bypass diode is normal. As described above, by focusing on the phenomenon that occurs when an open circuit failure occurs in a bypass diode and performing a determination regarding the occurrence of an open circuit failure, it is possible to detect a bypass diode that is likely to have an open circuit failure without using a dedicated measuring device. Therefore, it is possible to easily detect the occurrence of an open circuit failure in a bypass diode.

[0027] (9) A judgment program according to an embodiment of the present disclosure is a judgment program used in a judgment device used in a photovoltaic power generation system including a power generation unit including a solar cell panel, the solar cell panel being a cluster having a series circuit of solar cells, the solar cell panel including a plurality of the clusters capable of bypassing the series circuit via a bypass diode, the judgment program causing a computer to function as an acquisition unit that acquires measurement results of the output of each of the power generation units, and a judgment unit that performs a shadow judgment process regarding the influence of shadow on the power generation unit based on the measurement results acquired by the acquisition unit, the judgment unit determining the influence of shadow on the power generation unit in the shadow judgment process, If a positive determination is made that there is an impact, a fault determination process is performed regarding an open fault of the bypass diode based on the measurement results of the multiple power generation units for which the positive determination was made, and if, in the fault determination process, a relationship between a first statistical value of the output for a day of a first power generation unit, which is at least one of the multiple power generation units for which the positive determination was made, and a second statistical value of the output for the day of a second power generation unit, which is another power generation unit different from the first power generation unit among the multiple power generation units for which the positive determination was made, satisfies a predetermined condition, the determination unit makes a positive determination regarding the occurrence of an open fault of the bypass diode included in the solar panel of the first power generation unit.

[0028] In a photovoltaic power generation system, the output of a power generation unit in which an open circuit failure has occurred in a bypass diode and which is affected by a shadow may be significantly reduced compared to the output of other power generation units in which the bypass diode is normal and which are affected by a shadow. As described above, by focusing on the difference in the output of the power generation unit depending on whether or not an open circuit failure has occurred in the bypass diode and making a determination regarding the occurrence of an open circuit failure, it is possible to detect a bypass diode that is likely to have an open circuit failure without using a dedicated measuring device. Therefore, it is possible to easily detect the occurrence of an open circuit failure in a bypass diode.

[0029] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated. In addition, at least some of the embodiments described below may be arbitrarily combined.

[0030] <First embodiment> [Solar power generation system configuration] Fig. 1 is a diagram showing a configuration of a photovoltaic power generation system according to a first embodiment of the present disclosure. Referring to Fig. 1, a photovoltaic power generation system 401 includes four PCS (Power Conditioning System) units 80 and a cubicle 6. The cubicle 6 includes a copper bar 73.

[0031] In FIG. 1, four PCS units 80 are representatively shown, but a greater or lesser number of PCS units 80 may be provided.

[0032] Fig. 2 is a diagram showing a configuration of a PCS unit according to the first embodiment of the present disclosure. Referring to Fig. 2, a PCS unit 80 includes four current collecting units 60 and a PCS (power conversion device) 8. The PCS 8 includes a copper bar 7 and a power conversion section 9.

[0033] In FIG. 2, four current collecting units 60 are representatively shown, but a greater or lesser number of current collecting units 60 may be provided.

[0034] Fig. 3 is a diagram showing a configuration of a current collecting unit according to the first embodiment of the present disclosure. Referring to Fig. 3, current collecting unit 60 includes four solar cell units 74 and a current collecting box 71. Current collecting box 71 has a copper bar 72.

[0035] In FIG. 3, four solar cell units 74 are representatively shown, but a greater or lesser number of solar cell units 74 may be provided.

[0036] Fig. 4 is a diagram showing a configuration of a solar cell unit according to the first embodiment of the present disclosure. Referring to Fig. 4, solar cell unit 74 includes four power generation units 78 and a junction box 76. Power generation units 78 have solar cell panels 79. Junction box 76 has copper bars 77.

[0037] In FIG. 4, four power generation units 78 are representatively shown, but a greater or lesser number of power generation units 78 may be provided.

[0038] In this example, the power generation unit 78 is a string in which four solar cell panels 79 are connected in series.

[0039] In FIG. 4, four solar panels 79 are representatively shown, but a greater or lesser number of solar panels may be provided.

[0040] In the photovoltaic power generation system 401, output lines and aggregation lines, that is, power lines, from the multiple power generation units 78 are electrically connected to the PCS 8 shown in FIG.

[0041] More specifically, the output line 1 of the power generating unit 78 has a first end connected to the power generating unit 78 and a second end connected to the copper bar 77. The output lines 1 are aggregated into the aggregate line 5 via the copper bar 77. The copper bar 77 is provided, for example, inside the connection box 76.

[0042] When power generation unit 78 receives sunlight, it converts the energy of the received sunlight into DC power and outputs the converted DC power to output line 1.

[0043] 3 and 4, the aggregation line 5 has a first end connected to a copper bar 77 in a corresponding solar cell unit 74, and a second end connected to a copper bar 72. Each aggregation line 5 is aggregated into an aggregation line 2 via the copper bar 72. The copper bar 72 is provided inside a current collector box 71, for example.

[0044] Referring to Figures 1 to 4, in the solar power generation system 401, as described above, each output line 1 from multiple power generation units 78 is aggregated into an aggregated line 5, each aggregated line 5 is aggregated into an aggregated line 2, and each aggregated line 2 is electrically connected to a PCS 8.

[0045] More specifically, each aggregated line 2 has a first end connected to a copper bar 72 in a corresponding current collecting unit 60 and a second end connected to a 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 a power converter 9.

[0046] In PCS8, for example, when power conversion unit 9 receives DC power generated in each power generation unit 78 via output line 1, copper bar 77, aggregation line 5, copper bar 72, aggregation line 2, copper bar 7 and internal line 3, it converts the received DC power into AC power and outputs it to aggregation line 4.

[0047] The aggregated line 4 has a first end connected to the power conversion unit 9 and a second end connected to the copper bar 73 .

[0048] 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.

[0049] 5 is a diagram showing a configuration of a solar cell panel according to the first embodiment of the present disclosure. Referring to FIG. 5, an arrow in FIG. 5 indicates a direction of a current flowing through a solar cell panel 79.

[0050] 5, the solar cell panel 79 is configured by a plurality of clusters 93. In the example shown in FIG 5, the solar cell panel 79 is configured by a plurality of clusters 93, that is, clusters 93A, 93B, and 93C.

[0051] Each cluster 93 includes a plurality of solar cells 91 and a bypass diode 92. In the example shown in FIG.

[0052] In each cluster 93, ten solar cells 91 are connected in series. That is, the cluster 93 has a series circuit of solar cell panels 79. The cluster 93 can bypass the series circuit via a bypass diode 92. When an abnormality occurs, such as a decrease in the amount of power generated by the power generation unit 78 shown in FIG. 4, the current flowing through the solar cell panel 79 included in the power generation unit 78 bypasses the series circuit of the solar cell panel 79.

[0053] The number of solar cells 91 included in one cluster 93 is not limited to 10, and may be more or less.

[0054] In a cluster 93, an anode of a bypass diode 92 is connected to a node N2 between a first end of a series circuit of solar cells 91 in the cluster 93 and an input end of the cluster 93. A cathode of the bypass diode 92 is connected to a node N1 between a second end of the series circuit and an output end of the cluster 93.

[0055] 6 is a diagram showing a configuration of a determination system according to a first embodiment of the present disclosure. The determination system 301 includes a determination device 101, a plurality of monitoring devices 111, and a collection device 151.

[0056] In the determination system 301, the measurement results of the sensors in the monitoring device 111 and information including the sensor IDs and the like are transmitted to the collection device 151 on a regular or irregular basis.

[0057] The monitoring device 111 is provided, for example, in the power collecting unit 60. More specifically, four monitoring devices 111 are provided corresponding to the four solar cell units 74, respectively. Each monitoring device 111 is electrically connected, for example, to a corresponding output line 1 and aggregation line 5.

[0058] The monitoring device 111 monitors the power generation section 78 in the corresponding solar cell unit 74. For example, the monitoring device 111 measures the current flowing through the output line 1 of the power generation section 78 shown in Fig. 4 in the corresponding solar cell unit 74 using a sensor.

[0059] The collecting device 151 collects the monitoring results from each monitoring device 111. The collecting device 151 is provided, for example, near 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.

[0060] 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.

[0061] More specifically, each monitoring device 111 transmits monitoring results including measurement results of the current of the corresponding output line to the collecting device 151. Each monitoring device 111 transmits its monitoring results to the collecting device 151 at the same timing as the other monitoring devices 111, for example.

[0062] The collection device 151 is capable of transmitting and receiving information via the aggregation lines 2 and 5. Specifically, the collection device 151 performs power line communication with the monitoring devices 111 via, for example, the signal line 46 and the aggregation lines 2 and 5, and receives monitoring results from each monitoring device 111.

[0063] The collection device 151 transmits the monitoring results from each monitoring device 111 to the determination device 101 via a network such as the Internet.

[0064] 6 representatively shows four monitoring devices 111 provided corresponding to one current collecting unit 60, a greater or smaller number of monitoring devices 111 may be provided. Also, the determination system 301 includes one collecting device 151, but may include a plurality of collecting devices 151.

[0065] [Monitoring device configuration] 7 is a diagram showing a configuration of a monitoring device in the determination system according to the first embodiment of the present disclosure, in which the inside of the connection box 76 is shown in more detail.

[0066] 7, each of the output lines 1 includes a positive output line 1p and a negative output line 1n. The aggregated line 5 includes a positive aggregated line 5p and a negative aggregated line 5n. The copper bar 77 includes a positive copper bar 77p and a negative copper bar 77n.

[0067] Although not shown, the copper bars 72 in the current collection box 71 shown in FIG. 3 include a positive copper bar 72p and a negative copper bar 72n corresponding to the positive aggregated line 5p and the negative aggregated line 5n, respectively.

[0068] The positive output line 1p has a first end connected to the corresponding power generating unit 78 and a second end connected to the positive copper bar 77p. The negative output line 1n has a first end connected to the corresponding power generating unit 78 and a second end connected to the negative copper bar 77n.

[0069] The positive-side aggregated 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 collection box 71. The negative-side aggregated line 5n has a first end connected to the negative-side copper bar 77n and a second end connected to the negative-side copper bar 72n in the current collection box 71.

[0070] The monitoring device 111 includes an acquisition unit 11, a communication unit 14, and four current sensors 16. The monitoring device 111 may include a greater or lesser number of current sensors 16 depending on the number of output lines 1.

[0071] The monitoring device 111 is provided, for example, near the power generation unit 78. Specifically, the monitoring device 111 is provided, for example, inside the connection box 76 in which the copper bar 77 to which the output line 1 to be measured is connected is provided. The monitoring device 111 may be provided outside the connection box 76.

[0072] The monitoring device 111 is electrically connected to the positive aggregated line 5p and the negative aggregated line 5n via a positive power line 26p and a negative power line 26n, respectively. Hereinafter, each of the positive power line 26p and the negative power line 26n will also be referred to as a power line 26.

[0073] Each current sensor 16 is, for example, a Hall element type current probe connected between the power generation unit 78 and the PCS 8. The current sensor 16 measures the current C flowing through the corresponding negative output line 1n. The current sensor 16 outputs a signal at a level according to the current C to the acquisition unit 11. The current sensor 16 may also measure the current C flowing through the positive output line 1p.

[0074] The acquisition unit 11 acquires a measurement result of the output current of the power generation unit 78. More specifically, the acquisition unit 11 acquires a measurement result indicating the current in the output line 1. The acquisition unit 11 acquires a measurement value of the current C by each current sensor 16 based on a signal output from each current sensor 16, for example, during a predetermined measurement period.

[0075] The acquisition unit 11 acquires the measurement value of the current C by each current sensor 16 at each measurement time tm according to a predetermined measurement cycle Cm, creates measurement information including the acquired measurement value, the measurement time tm, and the ID of each of the four current sensors 16, and outputs the measurement information to the communication unit 14. The measurement cycle Cm is, for example, 10 minutes. Hereinafter, the ID of the current sensor 16 is also referred to as the "current sensor ID."

[0076] The communication unit 14 can perform power line communication with the collecting device 151 via the aggregation lines 2 and 5. For example, every time the communication unit 14 receives measurement information from the acquiring unit 11, the communication unit 14 includes the ID of the monitoring device 111 in the received measurement information and transmits the information to the collecting device 151 via the PCS 8.

[0077] Each time the collecting device 151 receives measurement information from each monitoring device 111 installed in the power collection unit 60 in the corresponding PCS unit 80, it creates monitoring result information including the measurement information received from each monitoring device 111 and the ID of the collecting device 151, and transmits the same to the determining device 101.

[0078] [Configuration of the judgment device] Fig. 8 is a diagram showing a configuration of a determination device according to a first embodiment of the present disclosure. With reference to Fig. 8, the determination device 101 includes a communication unit 31, a determination unit 32, and a storage unit 33. The determination unit 32 includes a shadow determination unit 41 and a fault determination unit 42. One or both of the communication unit 31 and the determination unit 32 are realized, for example, by a processing circuit including one or more processors. The storage unit 33 is, for example, a non-volatile memory included in the processing circuit. The communication unit 31 is an example of an acquisition unit.

[0079] The determination device 101 is, for example, a server, which periodically acquires monitoring result information from the collecting device 151 and processes the acquired monitoring result information. Note that the determination device 101 may be configured to be built into the collecting device 151. In the following, processing of the monitoring result information from one current collecting unit 60 by the determination device 101 will be representatively described.

[0080] (Communications Department) The communication unit 31 acquires the measurement results of the output of the power generation unit 78. More specifically, for example, the communication unit 31 performs a creation process of creating a plurality of time-series current data indicating the output currents of the plurality of power generation units 78 connected to the same junction box 76.

[0081] Specifically, for example, when the communication unit 31 receives monitoring result information from the collection device 151 , the communication unit 31 stores the received monitoring result information in the storage unit 33 .

[0082] When a specified daily processing timing, for example a specified time each day, arrives, the communication unit 31 acquires from the memory unit 33 multiple pieces of monitoring result information including reception times that belong to the period from 24 hours before the daily processing timing to the daily processing timing.

[0083] When the communication unit 31 acquires a plurality of pieces of monitoring result information from the storage unit 33, in a creation process, the communication unit 31 creates a plurality of pieces of time-series current data for each ID of the monitoring device 111 based on the plurality of pieces of monitoring result information.

[0084] 7 measures the current flowing through output line 1, for example, every 10 minutes. Therefore, each time-series current data created by communication unit 31 indicates the measurement result of the output current every 10 minutes in a certain day.

[0085] When the communication unit 31 creates the multiple time-series current data, it creates determination target information including the multiple time-series current data, the ID of the monitoring device 111, and the multiple current sensor IDs corresponding to the multiple time-series current data. Then, the communication unit 31 stores the created determination target information in the storage unit 33, and outputs it to the shadow determination unit 41.

[0086] The multiple time series of current data are not limited to the output currents of multiple power generation units 78 connected to the same junction box 76, and may, for example, represent the output currents of multiple power generation units 78 classified in advance by the user. Specifically, for example, the multiple time series of current data may represent the output currents of multiple power generation units 78 determined by the user to have similar power generation environments.

[0087] In addition, in the creation process, the communication unit 31 may create multiple time-series power data each indicating the measurement results of the power of multiple power generation units 78 connected to the same connection box 76, instead of multiple time-series current data. In this case, each monitoring device 111 includes a voltage sensor that measures the voltage of the output line 1 in addition to the four current sensors 16, and transmits the measurement results of the current sensor 16 and the measurement results of the voltage sensor to the determination device 101 via the collection device 151. Then, the communication unit 31 in the determination device 101 creates multiple time-series power data for each ID of the monitoring device 111 based on the measurement results of the current sensor 16 and the measurement results of the voltage sensor received. Here, multiple output lines 1 connected in parallel to the copper bar 77 are aggregated into an aggregated line 5, each aggregated line 5 is aggregated into an aggregated line 2, and each aggregated line 2 is electrically connected to the PCS 8. Therefore, the monitoring device 111 may be provided with at least one voltage sensor that measures the voltage of the aggregated line 5 or the aggregated line 2, instead of the voltage sensor that measures the voltage of the output line 1.

[0088] (Shadow detection processing) For example, the shadow determination unit 41 performs a shadow determination process regarding the influence of a shadow on the power generation unit 78 based on a plurality of time-series current data created by the communication unit 31. For example, in the shadow determination process, the shadow determination unit 41 determines whether or not at least one of the power generation units 78 is affected by a shadow. Furthermore, when at least one of the power generation units 78 is affected by a shadow, the shadow determination unit 41 determines a first time period T1 during which the power generation unit 78 is affected by a shadow and a second time period T2 during which the power generation unit 78 is not affected by a shadow.

[0089] More specifically, for example, in the shadow determination process, the shadow determination unit 41 determines whether or not the target power generation unit 78 to be determined is affected by a shadow by comparing time series current data corresponding to the power generation unit 78 to be determined (hereinafter also referred to as the "target power generation unit") with time series current data corresponding to another power generation unit 78 different from the target power generation unit (hereinafter also referred to as the "comparison power generation unit").

[0090] Specifically, for example, the memory unit 33 stores a correspondence table indicating the correspondence between a current sensor ID (hereinafter also referred to as a "target ID") corresponding to a target power generation unit and a current sensor ID (hereinafter also referred to as a "comparison ID") corresponding to a comparison power generation unit. The target ID is, for example, a current sensor ID included in the judgment target information from the communication unit 31. The correspondence table is, for example, registered in advance in the memory unit 33 by a user. Here, for example, a plurality of records are registered in the correspondence table, and in each record, the target ID and the comparison ID correspond one-to-one. The shadow determination unit 41 performs identification processing according to the correspondence table and performs shadow determination processing for each record.

[0091] For example, when the shadow determination unit 41 receives determination target information from the communication unit 31, it performs an identification process to identify a comparison ID corresponding to each current sensor ID included in the determination target information, i.e., for each target ID, by referring to the correspondence table in the memory unit 33.

[0092] In the shadow determination process, the shadow determination unit 41 compares the output current (hereinafter also referred to as "output current A1") in a specific time period T indicated by the time series current data corresponding to the target ID with the output current (hereinafter also referred to as "output current A2") in a time period T indicated by the time series current data corresponding to the identified comparison ID.

[0093] Specifically, for example, when the shadow determination unit 41 completes the identification process, it calculates the statistical value of the output current in the time period T for each piece of time-series current data. For example, the shadow determination unit 41 calculates the moving average amount of the output current for each hour in the time period T, which is the morning, daytime, and evening time periods, as the statistical value of the output current for each piece of time-series current data. That is, the shadow determination unit 41 creates time-series statistical data indicating the time-series change in the moving average amount of the output current for each piece of time-series current data included in the determination target information from the communication unit 31. Note that the shadow determination unit 41 may calculate the statistical value of the output current in the time period T for each piece of time-series current data before performing the identification process. In the following description, the morning time period is from 8:00 a.m. to 10:59 a.m., the daytime time period is from 11:00 a.m. to 1:59 p.m., and the evening time period is from 2:00 p.m. to 4:59 p.m.

[0094] The shadow determination unit 41 calculates the statistical value of the output current in time period T for each time series current data, and then checks whether the ratio of the moving average amount of the output current A2 (hereinafter also referred to as the "moving average amount B2") to the moving average amount of the output current A1 (hereinafter also referred to as the "moving average amount B1") is greater than or equal to a predetermined threshold value Th11.

[0095] When the ratio of the moving average amount B2 to the moving average amount B1 is equal to or greater than the threshold value Th11, the shadow determination unit 41 determines that the power generation unit 78 corresponding to the moving average amount B1 or the moving average amount B2 having a smaller value in the corresponding time period is affected by the shadow, and determines that the power generation unit 78 corresponding to the moving average amount having a larger value is not affected by the shadow. For example, the threshold value Th11 is registered in advance in the storage unit 33 by the user.

[0096] On the other hand, when the ratio of moving average amount B2 to moving average amount B1 is less than threshold value Th11, the shadow determination unit 41 does not determine whether the power generation unit 78 corresponding to the moving average amount B1 is affected by a shadow, and does not determine whether the power generation unit 78 corresponding to the moving average amount B2 is affected by a shadow.

[0097] FIG. 9 is a diagram for explaining the shadow determination process and the failure determination process performed by the determination device according to the first embodiment of the present disclosure.

[0098] In Fig. 9, the horizontal axis indicates time, and the vertical axis indicates the moving average amount of the output current. Also in Fig. 9, graph R11 is a graph showing the moving average amount of the output current of the power generation unit 78 that is not affected by a shadow. Graphs R12 and R13 are graphs showing the moving average amount of the output current of the power generation unit 78 that is affected by a shadow. Here, the explanation will be given assuming that the threshold value Th11 is 0.5.

[0099] 8 and 9, for example, in the correspondence table stored in the storage unit 33, a record Re11 in which the current sensor ID corresponding to the graph R12 is the target ID, a record Re12 in which the current sensor ID corresponding to the graph R13 is the target ID, and a record Re13 in which the current sensor ID corresponding to the graph R11 is the target ID are registered. In the records Re11 and Re12, for example, the current sensor ID corresponding to the graph R11 is registered as a comparison ID. In the record Re13, for example, the current sensor ID corresponding to the graph R12 is registered as a comparison ID. Note that in the record Re13, the current sensor ID corresponding to the graph R13 may be registered as a comparison ID, or another current sensor ID different from the current sensor ID corresponding to the graph R12 and the current sensor ID corresponding to the graph R13 may be registered as a comparison ID.

[0100] The ratio of the moving average amount of the output current at 8 o'clock and 17 o'clock shown in graph R12 to the moving average amount of the output current at 8 o'clock and 17 o'clock shown in graph R11 is less than 0.5. Also, the ratio of the moving average amount of the output current at 8 o'clock and 17 o'clock shown in graph R13 to the moving average amount of the output current at 8 o'clock and 17 o'clock shown in graph R11 is less than 0.5. On the other hand, the ratio of the moving average amount of the output current at 11 o'clock shown in graph R12 to the moving average amount of the output current at 11 o'clock shown in graph R11 is greater than 0.5. Also, the ratio of the moving average amount of the output current at 11 o'clock shown in graph R13 to the moving average amount of the output current at 11 o'clock shown in graph R11 is greater than 0.5.

[0101] In the example shown in FIG. 9, in the shadow determination process, the shadow determination unit 41 determines that the morning and evening time periods in graphs R12 and R13 are a first time period T1 that is affected by the shadow, and determines that the daytime time periods in graphs R12 and R13 are a second time period T2 that is not affected by the shadow.

[0102] Upon completing the shadow determination process, the shadow determination unit 41 creates shadow determination data for each of the created time-series statistical data in which the time-series statistical data is associated with a determination result. Then, the shadow determination unit 41 outputs the created shadow determination data and determination result information K1 including the ID of the monitoring device 111 and the IDs of the multiple current sensors included in the determination target information to the failure determination unit 42.

[0103] In addition, in each record of the correspondence table stored in the storage unit 33, the target ID and the comparison ID are not limited to a one-to-one correspondence, and a plurality of comparison IDs may correspond to one target ID. In this case, the shadow determination unit 41 performs the shadow determination process for each record in a brute-force manner. When the shadow determination unit 41 performs the shadow determination process in a brute-force manner, the determination accuracy regarding the influence of the shadow in the power generation unit 78 can be further improved compared to a configuration in which the shadow determination process is performed using two time-series current data.

[0104] Furthermore, when performing the shadow determination process in a brute force manner, the shadow determination unit 41 does not determine whether or not the power generation unit 78 corresponding to the larger of the two moving average amounts in each shadow determination process is affected by a shadow. Then, after performing the shadow determination process in a brute force manner, the shadow determination unit 41 determines the power generation unit 78 for which the determination was not performed as a power generation unit 78 that is not affected by a shadow. Therefore, the shadow determination unit 41 can be prevented from erroneously determining that one of the two power generation units 78 that are affected by a shadow is not affected by a shadow.

[0105] Further, the shadow determination unit 41 is not limited to a configuration in which the identification process is performed using a correspondence table registered in advance in the storage unit 33 by the user, but may be a configuration in which a correspondence table is created and the identification process is performed using the created correspondence table. In this case, for example, the shadow determination unit 41 creates a correspondence table for each record such that a current sensor ID corresponding to a power generation unit 78 installed in the vicinity of a target power generation unit corresponding to the record in the photovoltaic power generation system 401 is registered in the record as a comparison ID. Alternatively, the shadow determination unit 41 creates a correspondence table for each record such that a current sensor ID corresponding to a power generation unit 78 integrated in the same connection box 76 as the target power generation unit corresponding to the record is registered in the record as a comparison ID.

[0106] (Fault determination process) The failure determination unit 42 performs failure determination processing regarding an open failure of the bypass diode 92 based on the measurement result of the output of the power generation unit 78 acquired by the communication unit 31.

[0107] More specifically, for example, the failure determination unit 42 calculates a first statistical value S1 and a second statistical value S2 based on the measurement result of the output of the power generation unit 78 acquired by the communication unit 31 in the failure determination process.

[0108] Specifically, for example, when the failure determination unit 42 receives the determination result information from the shadow determination unit 41, the failure determination unit 42 selects, from among the multiple shadow determination data included in the determination result information K1, shadow determination data in which it is determined that the power generation unit 78 is affected by a shadow in at least one of the time periods of morning, daytime, and evening. Then, the failure determination unit 42 calculates a first statistical value S1 and a second statistical value S2 based on the selected shadow determination data. For example, the first statistical value S1 and the second statistical value S2 are the average value of the moving average amount of the output current in the first time period T1 and the average value of the moving average amount of the output current in the second time period T2, respectively. Note that the first statistical value S1 and the second statistical value S2 may be the representative value of the moving average amount of the output current in the first time period T1 and the representative value of the moving average amount of the output current in the second time period T2, respectively.

[0109] For example, as shown in graphs R12 and R13, when the power generation unit 78 is shaded in the morning and evening hours but not shaded during the daytime, the failure determination unit 42 calculates the average value of the moving average amount of the output current during the morning and evening hours as the first statistical value S1. The failure determination unit 42 also calculates the average value of the moving average amount of the output current during the daytime hours as the second statistical value S2.

[0110] Then, the fault determination unit 42 compares the first statistical value S1 and the second statistical value S2, and if the second statistical value S2 is equal to or smaller than the first statistical value S1, decides not to perform the fault determination process.

[0111] On the other hand, when the second statistical value S2 is greater than the first statistical value S1, the failure determination unit 42 decides to perform the failure determination process.

[0112] Then, in the failure determination process, when the first statistical value S1 is less than the predetermined threshold value Th21, the failure determination unit 42 makes a positive determination as to the occurrence of an open failure in the bypass diode 92.

[0113] More specifically, for example, the failure determination unit 42 checks whether the first statistical value S1 is less than the threshold value Th21 and is equal to or greater than a predetermined threshold value Th22, and whether the second statistical value S2 is equal to or greater than the threshold value Th21.

[0114] Specifically, the thresholds Th21 and Th22 are, for example, registered in advance in the storage unit 33 by a user. The threshold Th21 is a value greater than the threshold Th22. In the example shown in FIG. 9, the threshold Th21 is, for example, a value within a range from several tens of milliamperes to several hundreds of milliamperes, and the threshold Th22 is, for example, a value greater than 0 amperes. In the following description, the threshold Th21 is assumed to be 200 milliamperes, and the threshold Th22 is assumed to be 10 milliamperes. The threshold Th21 is an example of a first threshold, and the threshold Th22 is an example of a second threshold.

[0115] The reason why the fault determination unit 42 checks that the first statistical value S1 is equal to or greater than the threshold value Th22 and that the second statistical value S2 is equal to or greater than the threshold value Th21 in the fault determination process is to improve the accuracy of detection of an open fault in the bypass diode 92. For example, when another abnormality such as a break in the DC cable occurs in the power generation unit 78, the first statistical value S1 is less than the threshold value Th21, as in the case of an open fault, but unlike the case of an open fault, the first statistical value S1 is less than the threshold value Th22. Also, when another abnormality such as a short circuit occurs in the power generation unit 78, the first statistical value S1 is less than the threshold value Th21, as in the case of an open fault, but unlike the case of an open fault, the second statistical value S2 is less than the threshold value Th21.

[0116] 9, the first statistical value S1 in the morning and evening time periods affected by the shadow is 200 milliamperes or more. In this case, the failure determination unit 42 determines that an open failure of the bypass diode 92 has not occurred in the power generation unit 78 corresponding to the time-series current data shown in graph R12.

[0117] 9, the first statistical value S1 in the morning and evening time periods when there is an influence of a shadow is equal to or greater than 10 milliamperes and less than 200 milliamperes, and the second statistical value S2 in the daytime time period when there is no influence of a shadow is equal to or greater than 200 milliamperes. In this case, the failure determination unit 42 determines that an open failure has occurred in the bypass diode 92 in the power generation unit 78 corresponding to the time-series current data shown in the graph R13.

[0118] Then, for example, the failure determination unit 42 displays a screen indicating that an open failure has occurred in the bypass diode 92 on a display device (not shown). The failure determination unit 42 may output determination result information indicating that an open failure has occurred in the bypass diode 92 to the communication unit 31. In this case, the communication unit 31 transmits the determination result information received from the failure determination unit 42 to an external device via a network in a format such as e-mail.

[0119] Also, for example, when the fault determination unit 42 determines that an open fault has occurred in the bypass diode 92 in the power generation unit 78 corresponding to the time series current data shown in graph R13, it outputs open fault information indicating the current sensor ID corresponding to the power generation unit 78 to the shadow determination unit 41.

[0120] On the other hand, if the first statistical value S1 is less than the threshold value Th22, for example, if the first statistical value S1 is less than 0 milliamperes, the fault judgment unit 42 determines that another abnormality, such as a break in the DC cable, has occurred in the power generation unit 78, and determines that an open fault has not occurred in the bypass diode 92.

[0121] In addition, if the first statistical value S1 is greater than or equal to the threshold value Th21, or if the second statistical value S2 is less than the threshold value Th22, the fault judgment unit 42 determines that another abnormality, such as a short circuit, has occurred in the power generation unit 78, and determines that an open fault has not occurred in the bypass diode 92.

[0122] (Threshold Th21) For example, the threshold value Th21 is a value that is equal to or lower than the output of the power generation unit 78 operating in a state in which no open-circuit failure of the bypass diode 92 occurs and in a time period in which the power generation unit 78 is affected by a shadow.

[0123] More specifically, for example, if an open circuit failure occurs in the bypass diode 92 of the power generation unit 78, the output current of the power generation unit 78 during the time period affected by the shadow may be significantly reduced compared to when the bypass diode 92 is normal.

[0124] Specifically, for example, in a power generating unit 78 in which the bypass diode 92 is normal, the output current during a time period affected by the shadow is a value greater than several hundred milliamperes. On the other hand, in a power generating unit 78 in which an open-circuit failure of the bypass diode 92 has occurred, the output current during a time period affected by the shadow is a value within a range from several tens of milliamperes to several hundred milliamperes. Therefore, in this embodiment, as described above, the threshold value Th21 is set to a value within a range from several tens of milliamperes to several hundred milliamperes, specifically, to 200 milliamperes.

[0125] For example, the shadow determination unit 41 performs an update process to update the threshold value Th21 by using machine learning, statistical analysis, or other methods. Here, a configuration will be described in which the shadow determination unit 41 performs the update process by using k-means, which is an example of machine learning.

[0126] Specifically, for example, when the shadow determination unit 41 receives open circuit fault information from the fault determination unit 42 and a specified update processing timing, for example a specified day of each month, arrives, the shadow determination unit 41 acquires from the memory unit 33 multiple time series current data including measurement times tm belonging to the period from one month before the specified day to the specified day.

[0127] Then, the shadow determination unit 41 classifies the acquired multiple pieces of time-series current data into a group G1 of time-series current data when the power generation unit 78 is affected by the shadow and a group G2 of time-series current data when the power generation unit 78 is not affected by the shadow, by using k-means. In this case, the shadow determination unit 41 classifies the multiple pieces of time-series current data into the group G1 and the group G2 so that the time-series current data corresponding to the current sensor ID indicated by the open fault information from the fault determination unit 42, i.e., the time-series current data corresponding to the power generation unit 78 determined to have an open fault in the bypass diode 92, is not included in the group G1.

[0128] When the shadow determination unit 41 classifies the multiple time-series current data acquired from the storage unit 33 into group G1 and group G2, it checks the minimum value of the output current in the multiple time-series current data belonging to group G1. Then, the shadow determination unit 41 calculates the threshold value Th21, for example, by substituting the minimum value into a predetermined conversion formula. Here, for example, the shadow determination unit 41 calculates 80 percent of the minimum value as the threshold value Th21.

[0129] Then, the shadow determination unit 41 stores the calculated threshold value Th21 in the storage unit 33 as a new threshold value Th21. In the update process, the shadow determination unit 41 is not limited to a configuration in which the threshold value Th21 is updated using the minimum value of the output current in the group G1, but may be configured to calculate an average value of the output current based on a plurality of time-series current data belonging to the group G1 and update the threshold value Th21 using the average value. In this case, for example, the shadow determination unit 41 calculates 50 percent of the average value as the new threshold value Th21. In addition, when updating the threshold value Th21 using the average value, the shadow determination unit 41 may be configured to calculate the average value of the output current for each measurement time tm and to substitute the calculated average value into a conversion formula to calculate the threshold value Th21 for each measurement time tm.

[0130] In addition, in the update process, the shadow determination unit 41 may calculate the threshold value Th21 based on representative data of the multiple time-series current data belonging to the group G1. In this case, the shadow determination unit 41 calculates the threshold value Th21 by, for example, substituting the output current at each measurement time indicated by the representative data into a predetermined conversion formula.

[0131] Furthermore, the failure determination unit 42 is not limited to a configuration that performs the failure determination process using the threshold value Th21 registered in the storage unit 33, and may be configured to perform the failure determination process using the threshold value Th21 calculated by the shadow determination unit 41. In this case, the shadow determination unit 41 calculates the threshold value Th21 by performing a process similar to the update process, for example, and notifies the failure determination unit 42 of the calculation result. Furthermore, when calculating the threshold value Th21, the shadow determination unit 41 does not need to perform an update process of the threshold value Th21.

[0132] Furthermore, in the failure determination process, the failure determination unit 42 may be configured to determine the probability of an open failure occurring, instead of determining whether or not an open failure has occurred in the bypass diode 92. For example, the failure determination unit 42 may be configured to calculate a probability corresponding to the difference between the first statistical value S1 and the second statistical value S2, and display the calculated probability on the display device as the determination result.

[0133] The failure determination unit 42 may be configured to perform failure determination processing using a moving average amount of the output current for each hour in the first time zone T1 affected by the shadow and a threshold value Th21 set for each hour in the first time zone T1. In this case, the failure determination unit 42 makes a positive determination that an open failure has occurred in the bypass diode 92 when, for example, a certain moving average amount in the first time zone T1 is less than the corresponding threshold value Th21.

[0134] [Operation flow] FIG. 10 is a flowchart defining an operation procedure when the determination device according to the first embodiment of the present disclosure performs a failure determination process.

[0135] Referring to FIG. 10, first, the determination device 101 waits until the daily processing timing arrives (NO in step S101).

[0136] Then, when the daily processing timing arrives (YES in step S101), the determination device 101 creates multiple time-series current data indicating the output currents of multiple power generation units 78 connected to the same connection box 76 on a given day (step S102).

[0137] Next, the determination device 101 performs a shadow determination process regarding the influence of a shadow on each power generation unit 78, based on the created time-series current data of each power generation unit 78. For example, as described above, the determination device 101 determines whether or not at least one of the power generation units 78 is influenced by a shadow. Furthermore, when at least one of the power generation units 78 is influenced by a shadow, the determination device 101 determines a first time period T1 during which the power generation unit 78 is influenced by the shadow and a second time period T2 during which the power generation unit 78 is not influenced by the shadow (step S103).

[0138] Next, if the determination device 101 determines that at least one of the power generation units 78 is affected by the shadow (YES in step S104), it calculates a first statistical value S1 for a first time period T1 during which the power generation unit 78 is affected by the shadow, and a second statistical value S2 for a second time period T2 during which the power generation unit 78 is not affected by the shadow (step S105).

[0139] Next, if the second statistical value S2 is equal to or smaller than the first statistical value S1 (NO in step S106), the determination device 101 does not perform the malfunction determination process and waits until the next daily processing timing arrives (NO in step S101).

[0140] On the other hand, if the second statistical value S2 is greater than the first statistical value S1 (YES in step S106), the determining device 101 decides to perform a fault determination process for an open fault in the bypass diode 92 (step S107).

[0141] Next, if the first statistical value S1 is less than the threshold value Th21 and is greater than or equal to the threshold value Th22, and the second statistical value S2 is greater than or equal to the threshold value Th21 (YES in step S108), the determination device 101 determines that an open failure has occurred in the bypass diode 92 (step S109).

[0142] Next, the determination device 101 displays on the display device a screen showing the determination result indicating that an open fault has occurred in the bypass diode 92 (step S110), and waits until the next daily processing timing arrives (NO in step S101).

[0143] On the other hand, if the first statistical value S1 is less than the threshold value Th22, if the first statistical value S1 is greater than or equal to the threshold value Th21, or if the second statistical value S2 is less than the threshold value Th22 (NO in step S108), the determination device 101 determines that an open failure has not occurred in the bypass diode 92 (step S111), and waits until the next daily processing timing arrives (NO in step S101).

[0144] Furthermore, when the determination device 101 determines that each power generation unit 78 is not affected by the shadow (NO in step S104), it waits until the next daily processing timing arrives (NO in step S101).

[0145] In the determination system 301 according to the first embodiment of the present disclosure, the determination device 101 is configured to perform a shadow determination process regarding the influence of a shadow on the power generation unit 78 and perform a fault determination process when it is determined that there is an influence of the shadow, but this is not limited to the above. The determination device 101 may be configured to perform a determination process regarding the influence of dirt on the solar cell 91 in the power generation unit 78 and perform a fault determination process when it is determined that there is an influence of the dirt. In this case, the determination device 101 calculates a statistical value of the output in a first time slot T1 that is influenced by the dirt and a statistical value of the output in a second time slot T2 that is not influenced by the dirt as a first statistical value S1 and a second statistical value S2, respectively. In addition, the determination device 101 may be configured to include, instead of the shadow determination unit 41, an input receiving unit that receives information indicating a determination result regarding the influence of a shadow on each power generation unit 78 input by a user of the solar power generation system 401.

[0146] In addition, in the determination system 301 according to the first embodiment of the present disclosure, the determination device 101 is configured to make a positive determination as to the occurrence of an open circuit failure in the bypass diode 92 when the first statistical value S1 is less than the threshold value Th21 and is equal to or greater than a predetermined threshold value Th22 and the second statistical value S2 is equal to or greater than the threshold value Th21 in the failure determination process, but this is not limited to this. The determination device 101 may be configured to make a positive determination as to the occurrence of an open circuit failure in the bypass diode 92 when the first statistical value S1 is less than the threshold value Th21, when the first statistical value S1 is less than the threshold value Th21 and is equal to or greater than the threshold value Th22, or when the first statistical value S1 is less than the threshold value Th21 and the second statistical value S2 is equal to or greater than the threshold value Th21 in the failure determination process.

[0147] In the determination system 301 according to the first embodiment of the present disclosure, the determination device 101 is configured to perform a creation process for creating a plurality of time-series current data indicating the output currents of a plurality of power generation units 78 connected to the same connection box 76, but this is not limited to the above. Either the monitoring device 111 or the collecting device 151 may perform the creation process.

[0148] In addition, in the determination system 301 according to the embodiment of the present disclosure, the determination device 101 is configured to calculate the first statistical value S1 in the first time slot T1 in which the power generation unit 78 is affected by a shadow, and the second statistical value S2 in the second time slot T2 in which the power generation unit 78 is not affected by a shadow, but this is not limited to this. The determination device 101 may be configured to calculate, as the first statistical value S1 and the second statistical value S2, a statistical value of the output in a time slot including a part of the first time slot T1 and a statistical value of the output in a time slot including a part of the second time slot T2.

[0149] Next, another embodiment of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and the description thereof will not be repeated.

[0150] <Second embodiment> In the first embodiment described above, the determination device 101 performs a failure determination process when the power generation unit 78 is affected by a shadow in the first time zone T1 and is not affected by a shadow in the second time zone T2. In contrast, in the second embodiment of the present disclosure, the determination device 201 performs a failure determination process when the power generation unit 78 is affected by a shadow all day. Contents other than those described below are the same as those of the determination device 101 according to the first embodiment.

[0151] Fig. 8 also shows the configuration of a determination device 201 according to a second embodiment of the present disclosure. With reference to Fig. 8, when a positive determination is made in the shadow determination process by the shadow determination unit 41 that there is an influence of a shadow on a plurality of power generation units 78, the failure determination unit 42 in the determination device 201 performs a failure determination process based on the measurement results of the plurality of power generation units 78.

[0152] More specifically, for example, when a positive determination is made in the shadow determination process by the shadow determination unit 41 that there is an influence of a shadow on a plurality of power generation units 78, the failure determination unit 42 calculates a statistical value of the output current in one day for each of the power generation units 78 for which the positive determination has been made. The failure determination unit 42 may be configured to calculate a statistical value of the output current in a certain time period in one day.

[0153] FIG. 11 is a diagram for explaining the shadow determination process and the failure determination process performed by the determination device according to the second embodiment of the present disclosure.

[0154] In Fig. 11, the horizontal axis indicates time, and the vertical axis indicates the moving average amount of the output current. In Fig. 11, a graph R21 is a graph showing the moving average amount of the output current of the power generation unit 78 that is not affected by a shadow. Graphs R22 and R23 are graphs showing the moving average amount of the output current of the power generation unit 78 that is affected by a shadow. In this embodiment, the threshold value Th11 used in the shadow determination process is set to 0.5, similar to the first embodiment of the present disclosure.

[0155] 8 and 11, for example, in the correspondence table stored in the storage unit 33, a record Re21 in which the current sensor ID corresponding to the graph R22 is the target ID, a record Re22 in which the current sensor ID corresponding to the graph R23 is the target ID, and a record Re23 in which the current sensor ID corresponding to the graph R21 is the target ID are registered. In the records Re21 and Re22, for example, the current sensor ID corresponding to the graph R21 is registered as a comparison ID. In the record Re23, for example, the current sensor ID corresponding to the graph R22 is registered as a comparison ID. Note that in the record Re23, the current sensor ID corresponding to the graph R23 may be registered as a comparison ID, or another current sensor ID different from the current sensor ID corresponding to the graph R22 and the current sensor ID corresponding to the graph R23 may be registered as a comparison ID.

[0156] The ratio of the moving average amount of the output current at 8:00, 11:00, and 17:00 shown in graph R22 to the moving average amount of the output current at 8:00, 11:00, and 17:00 shown in graph R21 is less than 0.5. Also, the ratio of the moving average amount of the output current at 8:00, 11:00, and 17:00 shown in graph R22 to the moving average amount of the output current at 8:00, 11:00, and 17:00 shown in graph R21 is less than 0.5.

[0157] In the example shown in FIG. 11, in the shadow determination process, the shadow determination unit 41 determines that the morning, daytime, and evening time periods in graphs R22 and R23 are time periods affected by the shadow, i.e., determines that the corresponding power generation unit 78 is affected by the shadow all day long.

[0158] Upon completing the shadow determination process, the shadow determination unit 41 creates shadow determination data in which the time-series statistical data is associated with a determination result for each piece of time-series statistical data. Then, the shadow determination unit 41 outputs the created plurality of shadow determination data, as well as determination result information K2 including the ID of the monitoring device 111 and the plurality of current sensor IDs included in the determination target information, to the failure determination unit 42.

[0159] When the failure determination unit 42 receives the determination result information K2 from the shadow determination unit 41, it calculates, for each piece of shadow determination data included in the determination result information K2, a statistical value of the moving average amount of output current in one day of the corresponding power generation unit 78. That is, the failure determination unit 42 calculates a plurality of statistical values ​​corresponding to each of the plurality of power generation units 78 determined to be affected by the shadow all day long.

[0160] For example, for each piece of shadow determination data, the failure determination unit 42 calculates, as a statistical value, the average value of all of the moving average amounts of output current in one day of the corresponding power generation unit 78. Note that, for each piece of shadow determination data, the failure determination unit 42 may calculate, as a statistical value, a representative value of the moving average amounts of output current in one day of the corresponding power generation unit 78.

[0161] Then, when the relationship between a first statistical value of the output current for one day of power generation unit 78A, which is at least one of the multiple power generation units 78 determined to be affected by the shadow all day, and a second statistical value of the output current for one day of power generation unit 78B, which is another power generation unit 78 different from power generation unit 78A among the multiple power generation units 78, i.e., the comparison result, satisfies a predetermined condition, the fault judgment unit 42 makes a positive judgment that an open fault has occurred in the bypass diode 92 included in the solar panel 79 of power generation unit 78A.

[0162] More specifically, for example, when the fault judgment unit 42 calculates multiple statistical values, it checks whether the ratio of a statistical value S31, which is a statistical value corresponding to a certain power generation unit 78, to a statistical value S32, which is a statistical value corresponding to another power generation unit 78, among the multiple calculated statistical values, is less than a threshold value Th30.

[0163] When the ratio of the statistical value S32 to the statistical value S31 is less than the threshold value Th30, the failure determination unit 42 checks the current sensor ID corresponding to the statistical value S31 among the multiple current sensor IDs included in the shadow determination information from the shadow determination unit 41. Then, the failure determination unit 42 determines that an open failure has occurred in the bypass diode 92 in the power generation unit 78 corresponding to the checked current sensor ID.

[0164] On the other hand, when the ratio of the statistical value S32 to the statistical value S31 is equal to or greater than the threshold value Th30, the failure determination unit 42 determines that in each power generation unit 78, an open failure of the bypass diode 92 has not occurred.

[0165] The failure determination unit 42 may be configured to perform failure determination processing using a moving average amount of the output current for each hour in the shadow determination data included in the determination result information K2 from the shadow determination unit 41 and a threshold value Th30 set for each hour. In this case, the failure determination unit 42 makes a positive determination as to the occurrence of an open failure in the bypass diode 92 when, for example, a certain moving average amount in the shadow determination data is less than the corresponding threshold value Th30.

[0166] Furthermore, the shadow determining unit 41 may update the threshold value Th30 in the same manner as the above-mentioned update process.

[0167] [Operation flow] FIG. 12 is a flowchart defining an operation procedure when the determination device according to the second embodiment of the present disclosure performs a failure determination process.

[0168] 12, the processes in steps S201 and S202 are similar to the processes in steps S101 and S102 shown in FIG. 10, respectively.

[0169] Next, the determination device 201 performs a shadow determination process regarding the influence of a shadow on each power generation unit 78, based on the created time-series current data of each power generation unit 78. Here, in the shadow determination process, the determination device 201 determines whether or not each power generation unit 78 is influenced by a shadow all day long (step S203).

[0170] Next, when it is determined that each power generation unit 78 is affected by the shadow all day (YES in step S204), the determining device 201 calculates the statistical value of the output current of each power generation unit 78 for one day (step S205).

[0171] Next, when at least one of the calculated statistical values ​​S31 is smaller than the other statistical values ​​S32 by the threshold value Th30 or more (YES in step S206), the determination device 201 checks the current sensor ID corresponding to the statistical value S31 among the multiple current sensor IDs corresponding to the multiple statistical values. Then, the determination device 201 determines that an open failure has occurred in the bypass diode 92 in the power generation unit 78A, which is the power generation unit 78 corresponding to the checked current sensor ID (step S207).

[0172] Next, the determination device 201 displays on the display device a screen showing the determination result indicating that an open fault in the bypass diode 92 has occurred in the power generation unit 78A (step S208), and waits until the next daily processing timing arrives (No in step S201).

[0173] On the other hand, if the calculated multiple statistical values ​​do not include a statistical value that is smaller than the other statistical values ​​by more than the threshold value Th30 (NO in step S206), the determination device 201 determines that an open failure has not occurred in the bypass diode 92 in each power generation unit 78 (step S209).

[0174] Other configurations and operations are similar to those of the determination system 301 according to the first embodiment, and therefore detailed description will not be repeated here. Note that the determination device 201 may be configured to perform both the failure determination process in this embodiment and the failure determination process in the first embodiment of the present disclosure.

[0175] Incidentally, when the output of the power generation unit 78 in the photovoltaic power generation system 401 is normal, for example, when the power generation unit 78 is not affected by a shadow or the like, the open circuit voltage of the power generation unit 78 does not decrease, and the output current of the power generation unit 78 does not decrease either. In this case, in order to detect the occurrence of an open circuit fault in the bypass diode 92, it was necessary to inspect each solar cell panel 79 in the photovoltaic power generation system 401, for example, using a dedicated measuring device.

[0176] In contrast, the determination devices 101, 201 and the determination methods according to the embodiments of the present disclosure can easily detect the occurrence of an open fault in the bypass diode 92 by using the configurations and methods described above.

[0177] The above-described embodiments should be considered as illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0178] Each process (each function) in the above-mentioned embodiment is realized by a processing circuit including one or more processors. The processing circuit may be configured as an integrated circuit or the like in which one or more memories, various analog circuits, and various digital circuits are combined in addition to the one or more processors. The one or more memories store programs (instructions) that cause the one or more processors to execute each of the above processes. The one or more processors may execute each of the above processes according to the programs read from the one or more memories, or may execute each of the above processes according to a logic circuit designed in advance to execute each of the above processes. The processor may be various processors suitable for computer control, such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), and an ASIC (Application Specific Integrated Circuit). The physically separated processors may execute each of the above processes in cooperation with each other. For example, the processors mounted on each of a plurality of physically separated computers may cooperate with each other via a network such as a LAN (Local Area Network), a WAN (Wide Area Network), the Internet, etc. The program may be installed in the memory from an external server device or the like via the network, or may be distributed in a state stored in a recording medium such as a CD-ROM (Compact Disc Read Only Memory), a DVD-ROM (Digital Versatile Disc Read Only Memory), or a semiconductor memory, and installed in the memory from the recording medium.

[0179] The above description includes the following additional features. [Appendix 1] A determination device used in a solar power generation system having a power generation unit including a solar panel, the solar panel includes a plurality of clusters each having a series circuit of solar cells, the series circuit being bypassable via a bypass diode; an acquisition unit that acquires a measurement result of the output of the power generation unit; a determination unit that performs a fault determination process regarding an open fault of the bypass diode based on the measurement result acquired by the acquisition unit, When a first statistical value of the output in a first time period of a day is less than a predetermined first threshold value in the fault determination process, the determination unit makes a positive determination regarding the occurrence of the open fault; The determination device further comprises: a calculation unit that calculates the first statistical value and the second statistical value based on the measurement result acquired by the acquisition unit, The determination unit further performs a shadow determination process regarding an influence of a shadow on the power generation unit based on the measurement result acquired by the acquisition unit. the calculation unit determines a time period that is influenced by the shadow and a time period that is not influenced by the shadow based on the measurement result of the power generation unit for which the determination unit has made a positive determination that there is an influence of the shadow and the measurement result of the power generation unit for which the determination unit has made a negative determination that there is an influence of the shadow, The calculation unit calculates a statistical value of the output during a time period affected by the shadow as the first statistical value, and calculates a statistical value of the output during a time period not affected by the shadow as the second statistical value.

[0180] [Appendix 2] A determination device used in a solar power generation system having a power generation unit including a solar panel, the solar panel includes a plurality of clusters each having a series circuit of solar cells, the series circuit being bypassable via a bypass diode; A processing circuit is provided, The processing circuitry includes: Acquire a measurement result of the output of the power generation unit; performing a fault determination process for an open fault of the bypass diode based on the measurement result acquired by the acquisition unit; The determination device, in the failure determination process, makes a positive determination as to the occurrence of the open failure when a first statistical value of the output in a first time period of a day is less than a predetermined first threshold value.

[0181] [Appendix 3] A determination device used in a solar power generation system including a power generation unit including a solar cell panel, the determination device comprising: the solar panel includes a plurality of clusters each having a series circuit of solar cells, the series circuit being bypassable via a bypass diode; A processing circuit is provided, The processing circuitry includes: Acquire measurement results of the output of each of the power generation units; performing a shadow determination process regarding an effect of a shadow on the power generation unit based on the acquired measurement result; When a positive determination is made in the shadow determination process that there is an influence of the shadow on the plurality of power generating units, a failure determination process is performed regarding an open failure of the bypass diode based on the plurality of measurement results acquired by the acquisition unit; a determination device that, in the failure determination process, makes a positive determination about the occurrence of an open circuit failure in the bypass diode included in the solar panel of the first power generation unit when a relationship between a first statistical value of the output for a day of a first power generation unit, which is at least one of the multiple power generation units for which the positive determination was made, and a second statistical value of the output for a day of a second power generation unit, which is another power generation unit different from the first power generation unit among the multiple power generation units for which the positive determination was made, satisfies a predetermined condition. [Explanation of symbols]

[0182] 1,1n,1p output line 2,4,5,5n,5p Aggregation Line 3. Internal Lines 6. Cubicle 7,72,72n,72p,73,77,77n,77p Copper Bar 8 PCS 9 Power conversion section 11 Acquisition Department 14 Communications Department 16 Current Sensor 18 Memory section 26,26p,26n power line 31 Communications Department 32 Judgment section 33 Storage section 41 Shadow determination section 42 Failure determination section 46 Signal Line 60 Current collector unit 71 Current collector box 74 Solar cell unit 76 Junction box 78 Power Generation Division 79 Solar Panels 80 PCS units 91 Solar Cell 92 Bypass Diode 93, 93A, 93B, 93C Cluster 101,201 Judgment device 111 Monitoring equipment 151 Collection Device 301 Judgment System 401 Photovoltaic Power Generation System

Claims

1. A determination device used in a solar power generation system having a power generation unit including a solar panel, the solar panel includes a plurality of clusters each having a series circuit of solar cells, the series circuit being bypassable via a bypass diode; an acquisition unit that acquires a measurement result of the output of the power generation unit; a determination unit that performs a fault determination process regarding an open fault of the bypass diode based on the measurement result acquired by the acquisition unit, The determination unit, in the fault determination process, makes a positive determination that an open fault has occurred when a first statistical value of the output during a first time period of a day is less than a predetermined first threshold value.

2. The determination device according to claim 1 , wherein the first threshold value is a value equal to or lower than the output of the power generation unit operating in a state in which the open circuit fault does not occur and in a time period in which the power generation unit is affected by a shadow.

3. 3 . The determination device according to claim 1 , wherein the determination unit makes a positive determination regarding the occurrence of the open fault when the first statistical value is less than the first threshold value and is equal to or greater than a predetermined second threshold value in the fault determination process.

4. 3. The determination device of claim 1, wherein the determination unit makes a positive determination of the occurrence of an open circuit failure when, in the failure determination process, the first statistical value is less than the first threshold value and a second statistical value of the output in a second time period of the day that is different from the first time period is greater than or equal to the first threshold value.

5. A determination device used in a solar power generation system including a power generation unit including a solar cell panel, the determination device comprising: the solar panel includes a plurality of clusters each having a series circuit of solar cells, the series circuit being bypassable via a bypass diode; An acquisition unit that acquires measurement results of the output of each of the power generation units; a determination unit that performs a shadow determination process regarding an influence of a shadow on the power generation unit based on the measurement result acquired by the acquisition unit, when a positive determination is made in the shadow determination process that there is an influence of the shadow in the plurality of power generating units, the determination unit performs a fault determination process regarding an open fault of the bypass diode based on the measurement results of the plurality of power generating units in which the positive determination is made; The judgment unit makes a positive judgment about the occurrence of an open circuit failure of the bypass diode included in the solar panel of the first power generation unit when a relationship between a first statistical value of the output for a day of a first power generation unit, which is at least one of the multiple power generation units for which the positive judgment was made, and a second statistical value of the output for a day of a second power generation unit, which is another power generation unit different from the first power generation unit among the multiple power generation units for which the positive judgment was made, satisfies a predetermined condition.

6. A determination method for a determination device used in a solar power generation system having a power generation unit including a solar panel, comprising: the solar panel includes a plurality of clusters each having a series circuit of solar cells, the series circuit being bypassable via a bypass diode; Obtaining a measurement result of the output of the power generation unit; performing a fault determination process for an open fault of the bypass diode based on the acquired measurement result; A determination method, comprising: in the step of performing the fault determination process, if a first statistical value of the output during a first time period of a day is less than a predetermined first threshold, a positive determination is made regarding the occurrence of the open fault.

7. A determination method for a determination device used in a solar power generation system including a power generation unit including a solar panel, the determination method comprising: the solar panel includes a plurality of clusters each having a series circuit of solar cells, the series circuit being bypassable via a bypass diode; Obtaining a measurement result of the output of each of the power generation units; performing a shadow determination process regarding an influence of a shadow on the power generation unit based on the acquired measurement result; and when a positive determination is made as to the presence of the shadow effect in the plurality of power generating units, performing a fault determination process regarding an open fault of the bypass diode based on the measurement results of the plurality of power generating units in which the positive determination is made, A determination method in which, when a relationship between a first statistical value of the output for a day of a first power generation unit, which is at least one of the plurality of power generation units for which the positive determination was made, and a second statistical value of the output for a day of a second power generation unit, which is another power generation unit among the plurality of power generation units for which the positive determination was made, different from the first power generation unit, satisfies a predetermined condition, in the step of performing the fault determination processing, a positive determination is made regarding the occurrence of an open circuit fault in the bypass diode included in the solar cell panel of the first power generation unit.

8. A determination program for use in a determination device used in a solar power generation system having a power generation unit including a solar panel, the solar panel includes a plurality of clusters each having a series circuit of solar cells, the series circuit being bypassable via a bypass diode; Computer, an acquisition unit that acquires a measurement result of the output of the power generation unit; a determination unit that performs a fault determination process regarding an open fault of the bypass diode based on the measurement result acquired by the acquisition unit; It is a program to function as The judgment unit makes a positive judgment about the occurrence of an open circuit fault when a first statistical value of the output in a first time period of a day is less than a predetermined first threshold value in the fault judgment process.

9. A determination program for use in a determination device used in a solar power generation system including a power generation unit including a solar panel, the determination device comprising: the solar panel includes a plurality of clusters each having a series circuit of solar cells, the series circuit being bypassable via a bypass diode; Computer, An acquisition unit that acquires measurement results of the output of each of the power generation units; a determination unit that performs a shadow determination process regarding an influence of a shadow on the power generation unit based on the measurement result acquired by the acquisition unit; It is a program to function as when a positive determination is made in the shadow determination process that there is an influence of the shadow in the plurality of power generating units, the determination unit performs a fault determination process regarding an open fault of the bypass diode based on the measurement results of the plurality of power generating units in which the positive determination is made; The judgment program, in the failure judgment process, when a relationship between a first statistical value of the output for a day of a first power generation unit, which is at least one of the multiple power generation units for which the positive judgment was made, and a second statistical value of the output for a day of a second power generation unit, which is another power generation unit among the multiple power generation units for which the positive judgment was made, different from the first power generation unit, satisfies a predetermined condition.

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