JP2015198485A - Abnormality detection device, abnormality detection system, and abnormality detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an abnormality detection device capable of improving a detection accuracy of an abnormal detection upon string.SOLUTION: An abnormal detection device for detecting an abnormal of at least one string in a solar cell array detected in parallel to a plurality of strings in which a plurality of solar panels are connected in series comprises an obtaining unit for obtaining information of a voltage applied to a part of the string; and an abnormal detection unit for detecting an abnormality of the string when a voltage applied to the part is a predetermined threshold or more.

Description

  The present invention relates to an abnormality detection device, an abnormality detection system, and an abnormality detection method.

  2. Description of the Related Art Conventionally, solar power generation that uses solar panels (PV (Photo Voltaic) panels) to convert solar energy into electrical energy has been widespread. In solar power generation, waste, drainage, noise, vibration, and the like are not generated during power generation, and are expected to be used as an emergency power source.

  PV panels are often installed outdoors, such as on the rooftop, in order to increase power generation. Therefore, it is easily affected by natural phenomena (for example, wind, rain, snow) and other effects. The effects of natural phenomena and other factors can accumulate for many years, causing the failure of solar power generation systems including solar panels.

  As a device for diagnosing a failure (loss event) of a photovoltaic power generation system (photovoltaic system), a photovoltaic power generation system including a solar cell module and abnormality monitoring means is known (for example, see Patent Document 1). ).

  This solar cell module detects a plurality of solar cells connected to each other, a bypass diode connected in parallel to the plurality of solar cells, and heat generated by the bypass diode connected in parallel to the bypass diode. It has a thermal switch that operates. This abnormality monitoring means detects a change in the output voltage of the solar cell module and determines whether there is an abnormality in the solar cell module.

Special table 2013-532388 gazette

  In the monitoring apparatus described in Patent Document 1, the detection accuracy of abnormality detection including a failure in a string in which a plurality of solar panels are connected in series was insufficient.

  The present invention has been made in view of the above circumstances, and provides an abnormality detection device, an abnormality detection system, and an abnormality detection method that can improve the detection accuracy of abnormality detection in a string.

  The abnormality detection device of the present invention is an abnormality detection device that detects an abnormality of at least one string in a solar cell array in which a plurality of strings in which a plurality of solar panels are connected in series are connected in parallel. An acquisition unit that acquires information on a voltage applied to a part of the string, and an abnormality detection unit that detects an abnormality of the string when the voltage applied to the part is equal to or greater than a first threshold.

  The abnormality detection system of the present invention includes a solar cell array in which a plurality of strings in which a plurality of solar panels are connected in series are connected in parallel, and a voltage detection that detects a voltage applied to a part of the strings in the solar cell array. And an abnormality detection device that acquires information on the voltage from the voltage detection device and detects an abnormality of the string when a voltage applied to the part is equal to or higher than a first threshold.

  The abnormality detection method of the present invention is an abnormality detection method in an abnormality detection device that detects an abnormality of at least one string in a solar cell array in which a plurality of strings each having a plurality of solar panels connected in series are connected in parallel. Obtaining information on the voltage applied to a part of the string, and detecting an abnormality of the string when the voltage applied to the part is equal to or higher than a first threshold value.

  According to the present invention, it is possible to improve the detection accuracy of abnormality detection in a string.

The schematic diagram which shows the structural example of the photovoltaic power generation (PV: PhotoVoltic) system in embodiment. The schematic diagram which shows the structural example of the PV panel in embodiment The schematic diagram which shows the structural example of the subunit | mobile_unit in embodiment (A) The block diagram which shows the structural example of the data logger in embodiment, (B) The block diagram which shows the structural example of the monitor terminal in embodiment (A) The schematic diagram which shows an example of the relationship between the solar radiation amount which the PV panel in embodiment receives, and IV characteristic, (B) The schematic diagram which shows an example of the open circuit voltage and short circuit current in the IV characteristic of embodiment (C) The schematic diagram which shows an example of MPP ((Maximum Power Point) in the IV characteristic of embodiment The schematic diagram which shows the example of a change of the electric current and voltage of each PV string in the case of including the shadow or abnormality in embodiment The schematic diagram which shows the example of a change of the string voltage with respect to time in embodiment The schematic diagram which shows the example of a change of the panel voltage with respect to time in embodiment The flowchart which shows the 1st operation example at the time of the abnormality detection process of the data logger in embodiment (A) Schematic diagram showing an example of connection of one slave unit to one PV panel in the embodiment, (B) Change example of MPP when one slave unit is connected to one PV panel in the embodiment Schematic diagram showing The flowchart which shows the 2nd operation example at the time of the abnormality detection process of the data logger in embodiment (A) Schematic diagram showing an example of connection of one slave unit to two PV panels in the embodiment, (B) Change example of MPP when one slave unit is connected to two PV panels in the embodiment Schematic diagram showing The flowchart which shows the 3rd operation example at the time of the abnormality detection process of the data logger in embodiment The schematic diagram which shows the example of an input screen which concerns on the threshold value of the data logger in embodiment The schematic diagram for demonstrating the relationship between the voltage of the PV panel in embodiment, and a threshold value The schematic diagram which shows the structure of the subunit | mobile_unit in a comparative example

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Background to obtaining one embodiment of the present invention)
In the photovoltaic power generation system described in Patent Document 1, when a plurality of strings are connected in parallel and the plurality of strings are controlled by one power conditioner, a PV panel failure is detected based on the string voltage. It is difficult to do.

  For example, it is assumed that, among a plurality of strings connected in parallel, one PV panel fails in the first string, and all PV panels are normal in the second to fourth strings. Further, for example, it is assumed that each PV panel in the second to fourth strings operates at an MPP (Maximum Power Point). Further, it is assumed that MPP is 40 (V) and each string includes three PV panels. In this case, the voltages of the second to fourth strings are 40 (V) × 3 (units) = 120 (V), respectively.

  On the other hand, the PV panel in which the failure in the first string has occurred is assumed to have a maximum voltage of 30 (V). Even in this case, since the first to fourth strings are connected in parallel, the power conditioner controls the voltages of the first to fourth strings to be the same. Therefore, the voltage of the normal PV panel in the first string is 45 (V), and the voltage of the first string is 120 (V). Thus, even if some of the PV panels in the first string fail, the voltage of the first string does not change.

  The photovoltaic power generation system described in Patent Document 1 performs abnormality monitoring using a sensor circuit that detects a voltage at both ends of a solar cell string and a change thereof. Therefore, it is difficult to detect a failure in the first string. Therefore, the detection accuracy of abnormality detection in the string is insufficient.

  Hereinafter, an abnormality detection device, an abnormality detection system, and an abnormality detection method that can improve the detection accuracy of abnormality detection in a string will be described.

(First embodiment)
FIG. 1 is a schematic diagram illustrating a configuration example of a photovoltaic power generation system (PV system) 100 according to the first embodiment. The PV system 100 includes a photovoltaic power generation panel (PV panel) 10, a slave unit 20, a relay unit 30, a master unit 40, a connection box 50, a power conditioner (PCS) 60, a monitor terminal 70, and a data logger 80. And a monitor server 90. The PV system 100 is an example of an abnormality detection system. The data logger 80 is an example of an abnormality detection device.

  The PV panel 10 is a panel including a solar cell that converts light energy into electric power by a photoelectric effect. The PV panel 10 is a solar cell module (PV module) including a plurality of solar cells (PV cells). Further, the PV panels 10 are connected in series via the power line PL to form a solar cell string (PV string) 10ST, and the PV strings are connected in parallel via the power line PL to form a solar cell array (PV array) 10AR. It is formed. The PV string 10ST is an example of a string.

  The subunit | mobile_unit 20 detects (measures) at least the predetermined physical quantity (at least power generation voltage (output voltage of the PV panel 10)) obtained by the photoelectric effect of the PV panel 10 to which the subunit | mobile_unit 20 was connected. The predetermined physical quantity may include, for example, information on generated current, generated power, and generated power, in addition to information on voltage. The subunit | mobile_unit 20 transmits the information of predetermined | prescribed physical quantity as detection information to other apparatuses (for example, the relay machine 30, the main | base station 40, the data logger 80, the monitor server 90, or the monitor terminal 70).

  The position where the subunit | mobile_unit 20 is arrange | positioned is not restricted to the position of FIG. 1, You may connect to the other PV panel 10. FIG. In FIG. 1, although the subunit | mobile_unit 20 is connected to the one PV panel 10, it connects to the several adjacent PV panel 10, and the total value of the voltage of the several PV panel 10 may be detected. Multiple subunit | mobile_unit 20 may be installed for every PV string 10ST. The subunit | mobile_unit 20 detects the one part voltage of PV string 10ST.

  The relay device 30 relays communication between the child device 20 and the parent device 40, for example. The repeater 30 may relay communication between devices that perform other communication. Installation of the relay machine 30 may be omitted.

  For example, the parent device 40 receives detection information from one or more child devices 20 and transmits the detection information to the data logger 80. A plurality of master units 40 may be provided, or a single master unit 40 may be provided.

  The connection box 50 collects and connects the power lines PL as wiring in units of PV strings 10ST to the PCS 60. The connection box 50 includes, for example, a terminal for connecting the power line PL, a switch used for inspection and maintenance, a lightning arrester, and a backflow prevention diode (not shown) for preventing backflow of electricity. It is.

  The PCS 60 converts DC power corresponding to power generated by the plurality of PV panels 10 (for example, the PV array 10AR) into AC power. For example, the PCS 60 switches at a predetermined switching frequency to control the power transmitted through the power line PL.

  The PCS 60 performs, for example, MPPT (Maximum Power Point Tracking) control. The MPPT control of the PCS 60 is control for maximizing the total sum of generated power generated by the PV panel 10 included in the PV string 10ST. This MPPT control can be realized by a known method, for example, a hill-climbing method is adopted, and therefore, the generated power of each PV string 10ST in the PV array 10AR has a special situation (for example, occurrence of abnormality, occurrence of shadow) ), It remains substantially constant.

  The distribution board (not shown) distributes the electric power from the PCS 60 to each electric load (not shown).

  The data logger 80 is, for example, a PC (Personal Computer) or a server, and holds predetermined information aggregated by the parent device 40 (for example, detection information from the child device 20) in a predetermined memory. For example, the data logger 80 may execute an abnormality detection process based on detection information from the slave unit 20. For example, a predetermined server (for example, a remote server) on the parent device 40 or the network NW may have a data logger function and hold the predetermined information. For example, the data logger 80 receives detection information of each slave unit 20 from the master unit 40. The data logger 80 transmits the received detection information of each slave unit 20 to the monitor server 90 or the monitor terminal 70 via the network NW.

  The network NW may be a wired network (for example, an intranet or the Internet), or may be a wireless network (for example, a wireless LAN (Local Area Network), IrDA, Bluetooth (registered trademark), or WiGig).

  For example, the monitor server 90 receives detection information of each slave unit 20 from the data logger 80 and monitors the voltage of a predetermined PV panel 10 in each PV string 10ST. The monitor server 90 may monitor information other than the voltage according to the detection information from each slave unit 20.

  The monitor terminal 70 is possessed by a maintenance worker who performs maintenance work on the PV system 100 and is used for the maintenance work. For example, the monitor terminal 70 may be a portable dedicated terminal, or the function of the monitor terminal 70 may be incorporated in a smartphone.

  FIG. 2 is a diagram illustrating a configuration example around the PV panel 10. Here, although the subunit | mobile_unit 20 is connected to the PV panel 10, as shown in FIG. 1, the PV panel 10 to which the subunit | mobile_unit 20 is not connected also exists.

  The PV panel 10 includes a plurality of solar cell clusters (PV clusters) 10G. Each PV cluster 10G includes a plurality of PV cells 10C. The plurality of PV cells 10C included in the PV cluster 10G are connected in series. The PV cell 10C is a power generation element that converts light energy from sunlight into electric power. Further, bypass diodes BD (BD1 to BD3) are connected in parallel to each of the PV clusters 10G (10G1 to 10G3).

  In FIG. 2, three PV clusters 10G and three bypass diodes BD are provided, but the number is not limited to this. Moreover, in the PV cluster 10G, 12 PV cells 10C are connected in series, but the number is not limited to this. In general, the PV panel 10 includes a plurality of PV clusters 10G and a plurality of PV cells 10C. However, the PV panel 10 only needs to include at least one PV cell 10C.

  When a failure (abnormality) does not occur in the PV cell 10C or the connection line between the cells, each PV cluster 10G generates a voltage to generate power. Thereby, since a reverse voltage is applied to the bypass diode BD, the bypass diode BD does not pass current.

  On the other hand, it is assumed that a malfunction occurs in the PV cluster 10G1 (for example, failure of the PV cell 10C, disconnection between cells, see the arrow e in FIG. 2). In this case, the defective PV cell 10C or the connection line between the cells becomes a mere resistor without generating power, so that the energy generated by the other PV clusters 10G2 and 10G3 is consumed and the generated power of the PV panel 10 is consumed. Reduce. Moreover, if supply of an electric current is continued to the defective PV cell 10C or the connection line between cells, this PV cell 10C or the connection line between cells may be damaged by heat, for example. By the bypass diode BD1 connected in parallel to the PV cluster 10G1, the current flowing through the PV cluster 10G including the location where the failure has occurred is bypassed and passed.

  The current output from the bypass diode BD or the PV cluster 10G may be input to the slave unit 20.

  In addition, since the plurality of PV cells 10C forming the PV cluster 10G are connected in series, the current is common to each PV cell 10C. When the PV cell 10C having a low power generation capacity exists in the PV cluster 10G1, the operating point current value (string current) of the PV string 10ST in the MPPT control is the short-circuit current value of the PV cluster 10G1 (see, for example, FIG. 5B). The PV cluster 10G1 operates normally. In this case, the PV cell 10C having a low power generation capacity generates heat due to an increase in series resistance and consumes a part of the power.

  On the other hand, when the string current is larger than the short-circuit current value of the PV cluster 10G1, a reverse voltage (minus voltage) is applied to the PV cluster 10G1 by MPPT control. Therefore, the bypass diode BD1 operates (ON) to bypass the current.

  When the bypass diode BD is operated, no voltage is applied to the PV cluster 10G corresponding to the operated bypass diode BD, so that the voltage of the PV panel 10 is lowered. Let α be the voltage of the PV panel 10 when no bypass diode BD operates. For example, as shown in FIG. 2, when the PV panel 10 includes three bypass diodes BD, when one bypass diode BD operates, the voltage of the PV panel 10 becomes (2/3) α, and the bypass diode BD When two units are operated, the voltage of the PV panel 10 becomes (1/3) α.

  That is, in the PV panel 10 including β bypass diodes BD, when γ (β ≧ γ) bypass diodes BD are operated, the voltage of the PV panel 10 is ((β−γ) / β) · α. .

  FIG. 3 is a block diagram illustrating a configuration example of the slave unit 20.

  The subunit | mobile_unit 20 is provided with the DC / DC converter 21, the voltage regulator 22, CPU (Central Processing Unit) 26, the communication part 27, the input terminal 28, and the output terminal 29 (29a, 29b).

  The DC / DC converter 21 converts the variable DC voltage input from the input terminal 28 into a predetermined DC voltage (for example, 4 (V)). The DC voltage input from the input terminal 28 is a voltage supplied from the PV panel 10.

  The voltage regulator 22 adjusts the voltage from the DC / DC converter 21 to a predetermined voltage (for example, 3 (V)). The voltage regulator 22 can stably supply a voltage to the CPU 26, and the CPU 26 can be driven stably.

  The DC / DC converter 21 and the voltage regulator 22 have a function as a power supply unit that supplies a voltage to each unit in the slave unit 20.

  The CPU 26 implements various functions by executing a program stored in a ROM (Read Only Memory) (not shown) or a RAM (Random Access Memory) (not shown). For example, the CPU 26 executes various processes and controls. That is, the CPU 26 has a function as a control unit.

  For example, the CPU 26 detects a voltage divided by resistors r1 and r2 arranged between the output terminal 29a and the output terminal 29b. That is, the CPU 26 has a function as a voltage detection unit. The CPU 26 detects the output voltage of the PV panel 10 connected to the child device 20 from the detected voltage.

  The communication unit 27 is, for example, various data, various information, and other data via a wireless line with another child device 20, the relay device 30, the parent device 40, the data logger 80, the monitor server 90, or the monitor terminal 70. Communicate various signals. The communication method by the communication unit 27 includes, for example, DECT (Digital Enhanced Cordless Communication), Bluetooth (registered trademark), NFC (Near Field Communication), infrared, Zigbee (registered trademark), and wireless LAN (Local Area).

  For example, the communication unit 27 may communicate with another child device 20, the relay device 30, the parent device 40, the data logger 80, the monitor server 90, or the monitor terminal 70 via a wired line. The communication via a wired line includes, for example, power line communication (PLC: Power Line Communication).

  For example, the communication unit 27 transmits detection information including the voltage detected by the CPU 26 to the parent device 40. The detection information may include other predetermined physical quantities related to power generation.

  The input terminal 28 is connected to an arbitrary PV panel 10 in the PV string 10ST. The output terminal 29 is connected to the power line PL connected to the adjacent PV panel 10 or the connection box 50.

  Next, configuration examples of the parent device 40, the data logger 80, the monitor server 90, and the monitor terminal 70 will be described.

  Although not shown in particular, the parent device 40 includes, for example, a communication unit, a control unit, and a storage unit. The communication unit of the parent device 40 communicates with the child device 20, the data logger 80, the monitor server 90, or the monitor terminal 70 via, for example, a wired line or a wireless line. For example, the communication unit receives detection information of the slave unit 20 from the slave unit 20 or the relay unit 30 and transmits the detection information to the data logger 80. The control unit of the parent device 40 has, for example, a CPU and a ROM. When the CPU executes the program stored in the ROM, various processes of the control unit of the parent device 40 are performed. The storage unit of the parent device 40 holds various data and various information.

  FIG. 4A is a block diagram illustrating a configuration example of the data logger 80. The data logger 80 includes, for example, a communication unit 81, a control unit 82, and a storage unit 83.

  The communication unit 81 communicates various types of data, various types of information, and various types of signals with the slave unit 20, the master unit 40, the monitor server 90, or the monitor terminal 70 via, for example, a wired line or a wireless line. For example, the communication unit 81 receives detection information of the child device 20 from the parent device 40. For example, the communication unit 81 transmits the detection information of the slave unit 20 or the processing result of the abnormality detection process to the monitor server 90 or the monitor terminal 70. Therefore, the communication unit 81 has a function as an acquisition unit that acquires information on the voltage applied to a part of the string (for example, the PV string 10ST).

  For example, the communication unit 81 receives information for deriving a threshold value used for the abnormality detection process from the monitor terminal 70. For example, the communication unit 81 transmits information on the threshold value to the monitor terminal 70.

  The control unit 82 includes, for example, a CPU, a ROM, and a RAM. When the CPU executes a program stored in the ROM or RAM, various processes of the control unit of the data logger 80 are performed.

  The control unit 82 includes, for example, an abnormality detection unit 85 that detects the abnormality of the PV string 10ST with reference to the detection information of the child device 20 received by the communication unit 81. For example, when the voltage applied to a part of the PV string 10ST is equal to or higher than a predetermined threshold, the abnormality detection unit 85 detects an abnormality of the PV string 10ST.

  The control unit 82 includes, for example, a threshold value deriving unit 86 for deriving (for example, calculating) threshold values (for example, a lower limit value Th2 and an upper limit value Th1) used in the abnormality detection process. The threshold deriving unit 86 derives a lower limit value for detecting an abnormality in the PV panel 10 to which the child device 20 is connected, for example. For example, the threshold deriving unit 86 derives an upper limit value for detecting an abnormality in the PV panel 10 other than the PV panel 10 to which the child device 20 is connected.

  The storage unit 83 holds various data and various information received by the communication unit or generated by the control unit 82. The memory | storage part 83 memorize | stores the detection information of each subunit | mobile_unit 20, and the information of the determination result of the abnormality determination process with respect to each PV string 10ST, for example.

  Although not particularly illustrated, the monitor server 90 includes, for example, a communication unit, a control unit, and a storage unit. The monitor server 90 monitors, for example, detection information of the slave unit 20 (that is, information on a predetermined physical quantity related to power generation of the PV panel) and a processing result (abnormality presence / absence) of the abnormality determination process.

  The communication unit of the monitor server 90 communicates various data, various information, and various signals with the slave unit 20, the master unit 40, the data logger 80, or the monitor terminal 70 via, for example, a wired line or a wireless line. To do. The control unit of the monitor server 90 includes, for example, a CPU and a ROM. Various processes of the control unit of the monitor server 90 are performed by the CPU executing the program stored in the ROM. The storage unit of the monitor server 90 holds various types of data and various types of information received by the communication unit (for example, detection information of each slave unit 20 and information on processing results of abnormality determination processing).

  FIG. 4B is a block diagram illustrating a configuration example of the monitor terminal 70. The monitor terminal 70 includes, for example, a communication unit 71, a control unit 72, a storage unit 73, an operation unit 74, and a display unit 75.

  The communication unit 71 communicates various types of data, various types of information, and various types of signals with the slave unit 20, the master unit 40, the data logger 80, or the monitor server 90 via, for example, a wired line or a wireless line. For example, the communication unit 71 receives the detection information of each slave unit 20 and the information of the processing result of the abnormality determination process from the data logger 80. The communication unit 71 transmits, for example, information for deriving a threshold value accepted by the operation unit 74 to the data logger 80.

  The control unit 72 includes, for example, a CPU, a ROM, and a RAM. The CPU executes various programs of the control unit of the monitor terminal 70 by executing a program stored in the ROM or RAM.

  The storage unit 73 holds various data and various information received by the communication unit 71, for example. The memory | storage part 73 memorize | stores the detection information of each subunit | mobile_unit 20, and the information of the process result of an abnormality determination process, for example.

  For example, the operation unit 74 receives an input operation from a maintenance worker. For example, an input operation of at least a part of information displayed on the input screen shown in FIG. 14 is accepted.

  The display unit 75 displays, for example, various types of data and various types of information (for example, detection information detected by the slave unit 20 and information on the processing result of the abnormality detection process). The display unit 75 displays an input screen (see FIG. 14) for deriving a threshold value using the operation unit 74, for example.

  Therefore, for example, the monitor terminal 70 acquires necessary data from the data logger 80 in response to an input operation of a maintenance worker on the operation unit 74, and displays the acquired data on the display unit 75.

  Next, a change example (IV characteristic) of the current and voltage of the PV panel 10 will be described.

  FIG. 5A is a schematic diagram illustrating an example of the relationship between the amount of solar radiation received by the PV panel 10 and the IV characteristics. Referring to FIG. 5A, it can be understood that the greater the amount of solar radiation, the larger the current value for the same voltage. In addition, it can be understood that the maximum voltage (open voltage) in the IV characteristic does not depend much on the amount of solar radiation. In FIG. 5A, the amount of solar radiation is shown in units of (w / m 2), and the larger the numerical value, the larger the amount of solar radiation. In addition to the amount of solar radiation, the IV characteristic changes depending on the temperature.

  FIG. 5B is a schematic diagram illustrating an example of the open circuit voltage Vo and the short circuit current Si in the IV characteristic. The open circuit voltage Vo and the short circuit current Si depend on the characteristics of the PV panel 10. FIG. 5C is a schematic diagram illustrating an example of MPP in the IV characteristic. The MPP depends on, for example, the characteristics of the PV panel 10 and the amount of solar radiation received by the PV panel 10.

  Next, an example of changes in current and voltage of each PV string 10ST will be described.

  FIG. 6 illustrates that the PV system 100 includes four PV strings 10ST and five PV panels 10 for each PV string 10ST.

  That is, in FIG. 6, the PV string 10ST includes PV strings 10ST1 to 10ST4. PV string 10ST1 includes PV panels 10A1 to 10A5. PV string 10ST2 includes PV panels 10B1 to 10B5. PV string 10ST3 includes PV panels 10C1 to 10C5. PV string 10ST4 includes PV panels 10D1 to 10D5.

  FIG. 6 is a schematic diagram illustrating an example of an operating point in the IV characteristic of each PV panel 10 in each PV string 10ST when a shadow or an abnormality occurs in the PV panel 10D1 and the bypass diode BD operates. . The occurrence of a shadow indicates that at least a part of the PV panel 10 is in the shade. The occurrence of an abnormality includes, for example, a failure of the PV cell 10C or a failure due to a disconnection of a connection line between cells. The shadow is an example of a shadow.

  In FIG. 6, the arrangement of the left PV panels 10 and the arrangement of the IV characteristics of the right PV panels 10 match. For example, the IV characteristic of the PV panel 10 including a shadow or an abnormality is an IV characteristic surrounded by a dotted line in the IV characteristic group shown on the right side of the PV panel 10 group in FIG.

  For example, when the bypass diode BD operates in the PV panel 10D1 including a shadow or an abnormality, the voltage of the PV panel 10D1 decreases. On the other hand, since the PV strings 10ST1 to 10ST4 are connected in parallel, the voltage of the PV string 10ST4 including the shadow or abnormality changes so as to match the voltage of the PV strings 10ST1 to 10ST3 not including the shadow or abnormality. Therefore, in the PV string 10ST4 including shadows or abnormalities, the voltages of the PV panels 10D2 to 10D5 not including shadows or abnormalities are increased.

  When the voltage of the PV panels 10D2 to 10D5 that do not include shadows or abnormalities increases, for example, the voltage of the PV panel 10 that has been operating in the MPP is controlled to increase, and the operating voltage deviates from the MPP. In this case, referring to the IV characteristics shown in FIG. 6, when the operating voltage becomes higher than MPP, the current flowing through the PV panels 10D2 to 10D5 becomes small. The current flowing through the PV panels 10D2 to 10D5 matches the string current of the PV string 10ST4.

  As described above, in the PV string 10ST4 including a shadow or abnormality, the voltage of the PV panel 10D1 including the shadow or abnormality decreases, and the voltages of the PV panels 10D2 to 10D5 not including the shadow or abnormality increase.

  FIG. 7 is a schematic diagram illustrating an example of a voltage (string voltage) in each of the PV strings 10ST1 to 10ST4. FIG. 7 shows a change example of the string voltage from 5:00 to 19:00. 7 exemplifies that, in the PV system 100, there are four PV strings 10ST and five PV panels 10 for each PV string 10ST, as in FIG.

  In FIG. 7, it is assumed that the PCS 60 performs MPPT control. Therefore, when the PV panel 10 does not include shadows or abnormalities, the voltages of the PV strings 10ST1 to 10ST4 substantially match. In FIG. 7, the voltages of the PV strings 10ST1 to 10ST4 are slightly shifted due to measurement timing errors.

  In the time zone T1 of 7:00 to 9:00, the voltage of each PV string 10ST1 to 10ST4 fluctuates, and the time during which the voltage is lower than the MPPT voltage is increased. In the time zone T1, it is estimated that at least one of the PV strings 10ST1 to 10ST4 includes a shadow or an abnormality.

  The MPPT voltage of the PV panel 10 is the voltage of the PV panel 10 when the PV panel 10 operates in the MPP. The MPPT voltage in the PV string 10ST is a total value of the voltages of the PV panels 10 when all the PV panels 10 included in the PV string 10ST are operated in the MPP.

  In the time zone T2 from 12:00 to 14:00, the voltages of the PV strings 10ST1 to 10ST4 fluctuate and are lower than the MPPT voltage. In the time zone T2, it is estimated that at least one of the PV strings 10ST1 to 10ST4 includes a shadow or an abnormality. In addition, each string voltage tends to be lower in the time zone T2 than in the time zone T1. Therefore, it can be estimated that the number of PV strings 10ST including shadows or abnormalities is larger in the time zone T2 than in the time zone T1.

  Also in the time zone T3 from 16:00:00 to 18:30, the voltage of each PV string 10ST1-10ST4 fluctuates. It is estimated that there is a possibility that a PV string 10ST including a shadow or an abnormality may also exist in the time zone T3.

  FIG. 8 is a schematic diagram illustrating an example of the voltage (panel voltage) of each PV panel 10 in a predetermined PV string 10ST (for example, PV string 10ST4). That is, FIG. 7 shows the string voltage, and FIG. 8 shows the panel voltage corresponding to the string voltage of FIG.

  FIG. 8 shows an example of voltage change from 5:00 to 19:00. FIG. 8 illustrates that, in the PV system 100, there are four PV strings 10ST and five PV panels 10 for each PV string 10ST, as in FIG.

  In the time zone T1, the voltage of the PV panel 10D1 is greatly reduced from the MPPT voltage, and the voltages of the PV panels 10D2 to 10D5 are substantially larger than the MPPT voltage.

  Therefore, for example, it is presumed that the voltage of the PV panel 10D1 has decreased because the PV panel 10D1 includes shadows or abnormalities and the bypass diode BD is activated. Further, it is estimated that the voltage of the other PV panels 10D2 to 10D5 in the PV string 10ST4 has increased to compensate for the voltage decrease of the PV panel 10D1 along with the voltage decrease of the PV panel 10D1.

  That is, the voltage of the PV panel 10 including a shadow or abnormality decreases, and the voltage of the PV panel 10 that does not include a shadow or abnormality increases. The voltage obtained by adding the voltages of the PV panels 10D1 to 10D5 becomes the voltage (string voltage) of the PV string 10ST4. The voltage of the PV string 10ST4 substantially matches the voltage of the other PV strings 10ST1 to 10ST3 in the PV array 10AR by MPPT control by the PCS 60.

  In the time zone T2, the voltages of all the PV panels 10D1 to 10D5 in the PV string 10ST4 are lower than the MPPT voltage. In this case, it is estimated that the PV string 10ST4 is in the shadow and the other PV strings 10ST1 to 3 are also in the shadow. That is, it is estimated that the entire PV array 10AR is in shadow. In this case, even if the PCS 60 controls the string voltages to coincide with each other by the MPPT control, since the voltages of all the PV strings are lowered, it is estimated that none of the voltages of the PV panels 10D1 to 10D5 has increased. Is done.

  In the time zone T3, the voltage of the PV panel 10D3 is greatly reduced from the MPPT voltage. The voltages of the PV panels 10D4 and 10D5 tend to be lower than the MPPT voltage. On the other hand, the voltage of the PV panel 10 whose voltage is not lowered by the MPPT control by the PCS 60 tends to be higher than the MPPT voltage. In this case, the PV panel 10 whose voltage has decreased may be estimated to include a shadow or abnormality, and the PV panel 10 whose voltage has not decreased may be estimated not to include a shadow or abnormality. Further, when the voltage of a predetermined PV panel 10 decreases and the voltage of another PV panel 10 increases in the same PV string 10ST, it is estimated that the other PV strings 10ST1 to 10ST3 do not include a shadow or an abnormality. Also good.

  In addition, the voltage detected by the subunit | mobile_unit 20 shows the voltage depending on the PV panel 10 in which the subunit | mobile_unit 20 is installed. For example, when the subunit | mobile_unit 20 is installed in the PV panel 10 containing a shadow or abnormality, the voltage of the detected PV panel 10 reduces. For example, when the handset 20 is installed in the PV panel 10 that does not include a shadow or abnormality, the detected voltage of the PV panel 10 is in the vicinity of the MPPT voltage or higher than the MPPT voltage.

  In addition, when the PV panel 10 includes a shadow, it is estimated that there is no variation due to the time zone. Therefore, when the voltage characteristic varies with time in FIG. 8, it may be estimated that the PV panel 10 includes a shadow, and when the voltage characteristic does not vary with time, the PV panel 10 may be estimated to include an abnormality.

Next, an operation example during the abnormality detection process of the data logger 80 will be described.
FIG. 9 is a flowchart showing a first operation example during the abnormality detection process of the data logger 80.

  First, the communication unit 81 receives and acquires information on the voltage of the PV panel 10 from the child device 20 or the parent device 40 (S101).

  Subsequently, the abnormality detection unit 85 determines whether or not the acquired voltage is equal to or lower than the lower limit value Th2 (S102). Details of the lower limit Th2 will be described later. The lower limit value Th2 is an example of a second threshold value, and may be a fixed value or a variable value.

  When the acquired voltage is equal to or lower than the lower limit value Th2, the abnormality detection unit 85 determines whether or not a predetermined time has elapsed since the start of the process (abnormality detection process) in FIG. 9 (S103). The predetermined time is, for example, 2 hours to 3 hours. If the predetermined time has not elapsed, the process proceeds to S101.

  When the predetermined time has elapsed, the abnormality detection unit 85 determines that the PV panel 10 from which the voltage information has been acquired includes an abnormality, that is, the PV panel 10 includes an abnormality. For example, the communication unit 81 notifies (abnormality notification) that the PV panel 10 from which the voltage information has been acquired includes an abnormality (S104). The abnormality notification may be performed by communication with the child device 20, the parent device 40, the monitor server 90, or the monitor terminal 70, for example. The abnormality notification may be performed, for example, by voice output, display, or vibration in the data logger 80 or the communication destination device.

  In S102, when the acquired voltage is not less than or equal to the lower limit value Th2, the abnormality detection unit 85 determines whether or not the acquired voltage is greater than or equal to the upper limit value Th1 (S105). Details of the upper limit Th1 will be described later. The upper limit value Th1 is larger than the lower limit value Th2. The upper limit value Th1 is an example of a first threshold value, and may be a fixed value or a variable value.

  When the acquired voltage is equal to or higher than the upper limit value Th1, the abnormality detection unit 85 determines whether or not a predetermined time has elapsed since the start of the process (abnormality detection process) in FIG. 9 (S106). The predetermined time is, for example, 2 hours to 3 hours. If the predetermined time has not elapsed, the process proceeds to S101.

  When the predetermined time has elapsed, in the PV string 10ST including the PV panel 10 from which the voltage information has been acquired, when the PV panel 10 other than the PV panel 10 from which the voltage information has been acquired includes an abnormality. judge. For example, the communication unit 81 notifies that the PV panels 10 other than the PV panel 10 from which the voltage information has been acquired includes an abnormality (S107). The abnormality notification may be performed by communication with the child device 20, the parent device 40, the monitor server 90, or the monitor terminal 70, for example. The abnormality notification may be performed, for example, by voice output, display, or vibration in the data logger 80 or the communication destination device.

  According to the abnormality detection process shown in FIG. 9, it is possible to determine whether the PV panel 10 has a shadow or abnormality by determining whether or not the acquired voltage is not less than the upper limit value Th1 or not more than the lower limit value Th2. Further, by using the upper limit value or the lower limit value to determine the presence or absence of a shadow or an abnormality based on a part of the voltage of the PV string 10ST, it is possible to specify the approximate occurrence position of the shadow or abnormality in the PV string 10ST.

  For example, one slave unit 20 is installed for one PV string. When the acquired voltage is equal to or lower than the lower limit value, it is estimated that the PV panel 10 itself whose voltage is equal to or lower than the lower limit value includes a shadow or an abnormality. On the other hand, when the acquired voltage is equal to or higher than the upper limit value, when there are a plurality of PV panels 10 other than the PV panel 10 from which the voltage is acquired, at least one PV panel 10 of the plurality of PV panels 10 is shaded. Or it is presumed to include abnormalities.

  In FIG. 9, in S102 and S105, the acquired voltage is compared with a threshold value (for example, a lower limit value Th2 and an upper limit value Th1). Instead, information on the voltage of the PV panel 10 may be acquired a plurality of times in a predetermined time period, and a statistical value (for example, an average value) of the acquired voltage may be compared with a threshold value.

  Note that the abnormality detection unit 85 may detect an abnormality of the PV string 10ST when the acquired voltage is equal to or higher than the upper limit value Th1 without waiting for the elapse of a predetermined time.

  In addition, when it becomes No, without progressing predetermined time in S103, the abnormality detection part 85 may determine with the PV panel 10 from which the voltage information was acquired including the shadow part before progressing to S101. . Similarly, in S106, when the predetermined time has not elapsed and the answer is No, before proceeding to S101, the abnormality detection unit 85 includes a PV panel 10 other than the PV panel 10 from which the voltage information is acquired includes a shadow portion. May be determined.

  FIG. 10A is a schematic diagram illustrating an example of connection of one slave unit 20 to one PV panel 10. Reference numeral 15 denotes a junction box. FIG. 10B is a schematic diagram illustrating a change example of the MPP when one slave unit 20 is connected to one PV panel 10. 10A and 10B, it is assumed that the PV panel 10 includes three bypass diodes BD.

  The voltage of the PV panel 10 changes according to the number of operations of the bypass diode BD. For example, when the PV panel 10 does not include a shadow or abnormality and all of the bypass diodes BD included in the PV panel 10 do not operate, it is assumed that MPP is MPP13 and the MPPT voltage is 30 (V). In this case, for example, when the PV panel 10 includes a shadow or an abnormality and one of the bypass diodes BD included in the PV panel 10 operates, the MPP becomes the MPP 12 and the MPPT voltage becomes 20 (V). For example, when the PV panel 10 includes a shadow or an abnormality and two bypass diodes BD included in the PV panel 10 operate, MPP becomes MPP11 and MPPT voltage becomes 10 (V).

  FIG. 11 is a flowchart illustrating a second operation example during the abnormality detection process of the data logger 80. 11, steps that perform the same processing as the steps in FIG. 9 are denoted by the same reference numerals, and description thereof is omitted or simplified. In FIG. 11, it is assumed that there are three bypass diodes BD. In FIG. 11, it is assumed that the handset 20 is connected to any one PV panel 10 as illustrated in FIG.

  In the second operation example of FIG. 11, the lower limit value Th2 is (reference value R2 × 2/3) and the upper limit value Th1 is (reference value R1 × 1.1).

  In FIG. 11, S102B and S105B are executed instead of S102 and S105. S101, S103, S104, S106, and S107 are the same as those in FIG.

  In S102B, the abnormality detection unit 85 determines whether or not the acquired voltage is (reference value R2 × 2/3) or less. “2/3” in S102B is, for example, a value derived from (the number of bypass diodes BD (3) −1) / the number of bypass diodes. Therefore, when the number of bypass diodes BD changes, the value can be other than 2/3.

  In S105B, the abnormality detection unit 85 determines whether or not the acquired voltage is (reference value R1 × 1.1) or more. In FIG. 11, it is assumed that MPPT voltage <reference value × 1.1 <open circuit voltage (Vo) when bypass diode BD does not operate.

  The reference values R1 and R2 are, for example, a predetermined voltage value per PV panel 10, a value of the MPPT voltage when the bypass diode BD does not operate, or a past record of voltages measured in the same time zone. Value. The reference values R1 and R2 include, for example, voltage values (of the PV panel 10) detected by the slave unit 20 connected to another PV string 10ST different from the PV string 10ST that is the abnormality detection target. Further, the reference values R1 and R2 include, for example, statistical values (for example, average values) of voltage values (PV panel 10) detected by the slave unit 20 connected to other plural PV strings 10ST. That is, the statistical value of the voltage is derived from each voltage value applied to at least a part of each PV string 10ST.

  The other PV panel 10 may be another PV panel 10 included in the PV string 10ST including the PV panel 10 from which the voltage is to be acquired (that is, connected to the slave unit 20). The other PV panel 10 may be a PV panel 10 included in the PV string 10ST that does not include the PV panel 10 from which voltage is acquired.

  According to the abnormality detection process shown in FIG. 11, the shadow or abnormality of the PV string 10ST can be detected according to the voltage applied to a part of the PV string 10ST. In FIG. 11, whether or not there is an abnormality on the lower limit value Th2 side is determined according to whether or not the acquired voltage is equal to or less than a reference value R2 × (2/3). Accordingly, the value multiplied by the reference value R2 on the lower limit Th2 side is smaller than 6/5 of the third operation example described later, so that the determination accuracy on the lower limit Th2 side (that is, the determination accuracy in S104) can be improved.

  FIG. 12A is a schematic diagram illustrating a connection example of one slave unit 20 to two PV panels 10. FIG. 12B is a schematic diagram illustrating an example of a change in MPP when one slave unit 20 is connected to two PV panels 10. 12A and 12B, it is assumed that the PV panel 10 includes three bypass diodes BD.

  The voltage of the PV panel 10 changes according to the number of operations of the bypass diode BD. For example, when the PV panel 10 connected to the child device 20 does not include a shadow or abnormality and all of the bypass diodes BD included in the PV panel 10 do not operate, the MPP is MPP23 and the MPPT voltage is 60 (V). Suppose there is. In this case, for example, when the PV panel 10 connected to the slave unit 20 includes a shadow or an abnormality and one of the bypass diodes BD of the two PV panels 10 operates, the MPP becomes the MPP 22 and the MPPT voltage is 50. (V). For example, when the PV panel 10 connected to the slave unit 20 includes a shadow or an abnormality and two of the bypass diodes BD of the two PV panels 10 operate, the MPP becomes the MPP 21 and the MPPT voltage is 40 (V). It becomes.

  FIG. 13 is a flowchart showing a third operation example during the abnormality detection process of the data logger 80. In FIG. 13, steps that perform the same processing as the steps in FIG. 9 or FIG. 11 are denoted by the same reference numerals, and description thereof is omitted or simplified. In FIG. 13, it is assumed that there are three bypass diodes BD. In FIG. 13, it is assumed that the handset 20 is connected to the two PV panels 10 as illustrated in FIG.

  The third operation example of FIG. 13 illustrates that the lower limit value Th2 is (reference value R2 × 5/6) and the upper limit value Th1 is (reference value R1 × 2.2). The reference values R1 and R2 are the same as described in FIG. Therefore, the reference values R1 and R2 are values per PV panel 10.

  In FIG. 13, S102C and S105C are executed instead of S102 and S105. S101, S103, S104, S106, and S107 are the same as those in FIG.

  In S102C, the abnormality detection unit 85 determines whether or not the acquired voltage is equal to or less than (reference value R2 × 2 × (5/6)). “5/6” in S102C is, for example, [(number of bypass diodes BD (3) × number of PV panels 10 to be connected to slave 20 (2) −1) / number of bypass diodes × slave. 20, the number of PV panels 10 to be connected]. Therefore, when the number of bypass diodes BD changes, the value can be other than 5/6.

  In S105C, the abnormality detection unit 85 determines whether or not the acquired voltage is (reference value R1 × 2.2) or more. “2.2” in S105C is a value derived from, for example, “1.1 in S105B × number of PV panels 10 to be connected to the slave unit 20”.

  For example, when there is a shadow or abnormality in the PV panel 10 to which the slave unit 20 is connected, the voltage is 48 (V). In this case, if the reference values R1 and R2 are the MPPT voltage (60 (V)) when the bypass diode BD does not operate, 48 (V) <60 (V), and the process proceeds from S102C to S103. Therefore, it can be determined that the PV panel 10 to which the slave unit 20 is connected has a shadow or an abnormality.

  For example, when there is no shadow or abnormality in the PV panel 10 to which the slave unit 20 is connected, and there is a shadow or abnormality in another PV panel 10 of the same PV string 10ST, it is 68 (V). In this case, if the reference values R1 and R2 are the MPPT voltage (60 (V)) when the bypass diode BD does not operate, 68 (V)> 66 (V), and the process proceeds from S105C to S106. Therefore, it can be determined that there is a shadow or an abnormality in another PV panel 10 in the same string other than the PV panel 10 to which the slave unit 20 is connected.

  According to the abnormality detection process shown in FIG. 13, the shadow or abnormality of the PV string 10ST can be detected according to the voltage applied to a part of the PV string 10ST. In FIG. 13, whether or not there is an abnormality on the upper limit value Th1 side is determined according to whether or not the acquired voltage is the reference value R1 × 2.2. Accordingly, the value multiplied by the reference value R1 on the upper limit value Th1 side is larger than 1.1 in the second operation example, so that the determination accuracy on the upper limit value Th1 side (that is, the determination accuracy in S107) can be improved.

  Note that one slave unit 20 may be connected to three or more PV panels 10. In this case, the voltage of three or more PV panels 10 connected in series is a detection target. The wiring connected to the slave unit 20 is connected to the PV panels 10 at both ends among the three or more PV panels 10. Wiring is connected between PV panels 10 other than both ends between adjacent PV panels 10.

Next, an example of an input screen for deriving a threshold value used for abnormality determination processing will be described.
FIG. 14 is a schematic diagram illustrating an example of an input screen displayed on the monitor terminal 70, for example.

  The input screen of the monitor terminal 70 includes, for example, open-circuit voltage (Vo), failure detection date and time, upper reference value (R1), lower reference value (R2), maximum power operating point (MPP), failure detection time, upper limit A coefficient (k1) and a lower limit coefficient (k2) are included. The input screen of the monitor terminal 70 includes, for example, the number of bypass diodes BD (d), comparison time (an example of a predetermined time in FIGS. 11 and 13), an upper limit value (Th1), a lower limit value (Th2), and one PV The number (n) of the PV panels 10 in the string 10ST and the number (m) of the PV panels 10 to which the handset 20 is connected are included. Note that failure detection is an example of abnormality detection.

  Of the information displayed on the input screen, information input by the operator of the monitor terminal 70 is a value other than the upper limit coefficient k1, the lower limit coefficient k2, the upper limit value Th1, and the lower limit value Th2, for example. Among the information in FIG. 14, information derived based on information input by the operator is, for example, an upper limit coefficient k1, a lower limit coefficient k2, an upper limit value Th1, and a lower limit value Th2.

  Of the information input by the operator of the monitor terminal 70, data that can be acquired from other devices (for example, the slave unit 20, the master unit 40, the data logger 80, or the monitor server 90) is not input. Data acquired from other devices may be reflected in the display. This data includes, for example, values of open circuit voltage (Vo) and maximum power operating point (MPP).

  The operator of the monitor terminal 70 confirms the input screen displayed by the display unit 75 and performs an input operation. When the operation unit 74 of the monitor terminal 70 receives an input from the operator, the communication unit 71 transmits information (input information) input by the input operation to the data logger 80.

  In the data logger 80, when the communication unit 81 receives the input information from the monitor terminal 70, the threshold value deriving unit 86 uses the information on the threshold value based on the input information (for example, the upper limit coefficient k1, the lower limit coefficient k2, the upper limit value Th1, A lower limit value Th2) is derived. The communication unit 81 transmits information regarding the threshold derived by the threshold deriving unit 86 to the monitor terminal 70.

  In the monitor terminal 70, when the communication unit 71 receives information on the threshold from the data logger 80, the display unit 75 displays the information on the threshold together with, for example, input information. Accordingly, an input screen as shown in FIG. 14 is displayed on the display unit 75.

  Next, an example of threshold value derivation will be described.

  The threshold derivation unit 86 of the data logger 80 may calculate the upper limit value Th1 based on input information from the monitor terminal 70. The calculation formula of the upper limit value Th1 is expressed by, for example, the following (Formula 1).

Th1 = (R1 × k1) × m
k1 = [(1 / d) × (1 / (n−1)] + 1 (Expression 1)

  The upper limit coefficient (k1) in (Expression 1) indicates a rate at which the voltage of one normal PV panel 10 increases due to the fact that one PV cluster 10G includes a shadow or an abnormality. For example, when d = 3, n = 4, and m = 1, k1 = 1.1 is calculated as in FIG.

  The threshold derivation unit 86 of the data logger 80 may calculate the lower limit value Th <b> 2 based on input information from the monitor terminal 70. The calculation formula of the lower limit Th2 is expressed by, for example, the following (Formula 2) or (Formula 3).

Th2 = (R2 × k2) × m
k2 = 1− (1 / (d × m)) (Formula 2)

  The lower limit coefficient (k2) in (Expression 2) indicates the rate at which the voltage of the PV panel 10 including shadows or abnormalities drops due to one PV cluster 10G including shadows or abnormalities.

Th2 = (R2 × k2) + R1 × k1 × (m−1)
k2 = 1- (1 / d) (Formula 3)
Note that R1 = R2 = MPP.

  The lower limit (Th2) in (Expression 3) is the voltage (R2 × k2) of the PV panel 10 including a shadow or an abnormality and the voltage (R1 × k1 ×) of the remaining normal PV panel 10 in one PV string 10ST. (M-1)) and the total value.

  Next, specific examples of threshold values (for example, upper limit value Th1 and lower limit value Th2) will be described.

  FIG. 15 is a schematic diagram for explaining the relationship between the voltage of the PV panel 10 and threshold values (upper limit value Th1 and lower limit value Th2). FIG. 15 illustrates that the PV string 10 </ b> ST includes the panels 1 to 4 as the PV panel 10.

  In (A), for example, when panels 1 to 4 do not include shadows or abnormalities and operate normally, they operate at an MPPT voltage (for example, 30 (V)).

  In (B), when the panel 1 includes a shadow or abnormality and the voltage of the panel 1 is 20 (V), the voltage of the panels 2 to 4 is about 33 (V) by the MPPT control by the PCS 60. Become. Accordingly, the voltage of the PV string 10ST including the panels 1 to 4 is about 120 (V), and the string voltage is substantially constant when the shadow or abnormality is included and when the shadow or abnormality is not included.

  In (C), for example, it is assumed that the number of PV panels 10 to be connected to the slave unit 20 is one (m = 1) and the slave unit 20 is connected to the panel 1. In this case, the actual value of voltage detection by the handset 20 is 20 (V) as shown in (B). On the other hand, the lower limit (Th2) calculated by the data logger 80 is 20 (V) according to (Expression 2) or (Expression 3). Therefore, in this case, the voltage of the panel 1 is lower than the lower limit (Th2).

  In (D), for example, it is assumed that the number of PV panels 10 to be connected to the slave unit 20 is two (m = 2) and the slave unit 20 is connected to the panels 1 and 2. In this case, the actual measurement value of the voltage detection by the handset 20 is 53 (V) as shown in (B). On the other hand, the lower limit (Th2) calculated by the data logger 80 is 20 + 33 = 53 (V) according to (Equation 3). Therefore, in this case, the voltages of the panels 1 and 2 are lower than the lower limit (Th2).

  In (E), for example, it is assumed that the number of PV panels 10 to be connected to the slave unit 20 is one (m = 1) and the slave unit 20 is connected to the panel 3. In this case, the actual measurement value of voltage detection by the handset 20 is 33 (V) as shown in (B). On the other hand, the upper limit (Th1) calculated by the data logger 80 is 33 (V) according to (Equation 1). Therefore, in this case, the voltage of the panel 3 becomes equal to or higher than the upper limit value (Th3).

  In (F), for example, it is assumed that the number of PV panels 10 to be connected to the child device 20 is three (m = 3), and the child device 20 is connected to the panels 2 to 4. In this case, the actual value of voltage detection by the slave unit 20 is 99 (V) as shown in (B). On the other hand, the upper limit (Th1) calculated by the data logger 80 is 99 (V) according to (Equation 1). Therefore, in this case, the voltages of the panels 2 to 4 are equal to or higher than the upper limit value (Th3).

  According to the example of FIG. 15, the data logger 80 can be obtained by using (Equation 1) to (Equation 3) without depending on the attachment position of the slave unit 20 with respect to the PV panel 10 or the number of PV panels 10 to be connected. Can set appropriate threshold values (for example, upper limit value Th1, lower limit value Th2).

  As described above, according to the PV system 100, the slave unit 20 detects the voltage of an arbitrary PV panel 10 in the PV string 10ST, and collects the detection information in the data logger 80, for example. The data logger 80 can analyze the presence / absence of an abnormality in the PV string 10ST, for example, using the detection information of the slave unit 20.

  Here, as a comparative example, a case will be described in which the slave unit 20X detects the current of the PV panel and the presence / absence of an abnormality is determined using the current information. FIG. 16 is a schematic diagram illustrating a configuration of the slave unit 20X of the comparative example.

  In the subunit | mobile_unit 20X, the shunt resistance Rx is arrange | positioned in series between the input terminal 28X side and the output terminal 29X side. The subunit | mobile_unit 20X detects the electric current which flows through the shunt resistance Rx. The presence or absence of abnormality is determined based on this current.

  For example, when a large number of PV panels are included in the PV string 10ST, the PV panels are connected in series in the same string, so that the current flowing through the shunt resistor Rx becomes a large current. Further, the slave unit 20 needs to be guaranteed to operate for a long period of time (for example, 20 years), but it may be difficult to guarantee the long-term operation due to the failure of the shunt resistor Rx.

  When the shunt resistor Rx breaks down, it is disconnected, and power cannot be sent from the input terminal 28X to the output terminal 29X, and power generation by the PV panel may stop. In this case, it leads to loss of power generation opportunities.

  In the monitoring of the current value in the shunt resistor Rx, when the PV panel 10 fails, the current value measured by the slave unit 20X is 0 (A). Therefore, it is difficult to distinguish between the failure of the shunt resistor Rx and the failure of the PV panel 10.

  On the other hand, according to the PV system 100, since the presence or absence of abnormality of the PV string 10ST is determined without using the shunt resistor and without using the current, the concern when the shunt resistor Rx exists is eliminated. For example, it is possible to reduce the possibility of loss of power generation opportunities due to component failures in the slave unit 20X. In addition, since the current detector is not necessary, the circuit configuration is simplified, and the cost required for the handset 20 can be reduced. Moreover, the possibility of failure of the components in the slave unit 20 due to a large current is reduced, and long-term guarantee can be improved.

  The present invention is not limited to the configuration of the above-described embodiment, and any configuration can be used as long as the functions shown in the claims or the functions of the configuration of the present embodiment can be achieved. Is also applicable.

  For example, in the above-described embodiment, the slave unit 20 may perform MPPT (Maximum Power Point Tracking) control. The MPPT control of the slave unit 20 is control for maximizing the power generation amount of the PV panel 10 to which the slave unit 20 is connected. This MPPT control can be realized by a known method, for example, a hill climbing method is adopted.

  For example, in the above-described embodiment, the abnormality detection process is illustrated as being executed by the data logger 80. However, other devices (for example, the parent device 40 and the monitor server 90) may be executed. That is, another device may include an abnormality detection unit and a threshold deriving unit. The abnormality detection unit and the threshold value deriving unit may be provided in separate devices.

  For example, in the above embodiment, the communication unit 81 of the data logger 80 may receive information on the voltage of at least one PV panel 10 in the PV string 10ST. In this case, when the state in which the received voltage is equal to or higher than the upper limit value Th1 is detected a plurality of times (for example, three times) or more in a predetermined period, the abnormality detection unit 85 performs the above-described at least one PV panel in the PV string 10ST. An abnormality of the PV panel 10 other than 10 may be detected. Further, when the state where the received voltage is equal to or lower than the lower limit value Th2 is detected a plurality of times (for example, three times) or more in a predetermined period, the abnormality detection unit 85 performs the above-described at least one PV panel 10 in the PV string 10ST. Anomalies may be detected. This predetermined period includes, for example, one day, half a day, or a time period in which the amount of solar radiation is equal to or greater than a predetermined amount (for example, 11: 00 to 15:00).

(Overview of one embodiment of the present invention)
An abnormality detection apparatus according to an aspect of the present invention is an abnormality detection apparatus that detects an abnormality of at least one string in a solar cell array in which a plurality of strings in which a plurality of solar panels are connected in series are connected in parallel. , An acquisition unit that acquires information on a voltage applied to a part of the string, and an abnormality detection unit that detects an abnormality of the string when the voltage applied to the part is equal to or greater than a first threshold.

  According to this configuration, the abnormality of the string can be detected by using the increase in the voltage of the solar panel from which the voltage is acquired. Further, the abnormality of the string can be detected by using the voltage applied to a part of the string instead of the voltage of the entire string. Therefore, in an environment where a plurality of strings are connected in parallel, the accuracy of string abnormality detection by voltage can be improved. Further, it is possible to determine whether or not there is an abnormality in the string without connecting a current detection component (for example, a shunt resistor) in series with the string. Therefore, the failure of a component for current detection breaks the string, and it is possible to suppress the loss of power generation opportunities by the photovoltaic power generation panel of the string.

  In the abnormality detection device of one aspect of the present invention, the acquisition unit acquires information on the voltage of at least one solar panel in the string, and the abnormality detection unit receives the voltage acquired by the acquisition unit as the first voltage. When a state where the voltage is equal to or higher than 1 and the voltage is equal to or higher than the first threshold is continued for a predetermined time or longer, an abnormality of a solar panel other than the at least one solar panel in the string is detected.

  According to this configuration, the state of the string can be determined using the fact that a plurality of strings are connected in parallel. For example, when the voltage of a solar panel including an abnormality or a shadow decreases, the voltages of other solar panels in the same string increase. Therefore, based on the fact that the voltage of the solar panel from which the voltage is acquired is relatively high, it can be determined that the solar panel other than the acquisition target has an abnormality or a shadow. In addition, when an abnormality occurs, it is possible to determine the presence or absence of an abnormality using the fact that there is little time variation in voltage. Moreover, the approximate position of the solar panel having an abnormality (here, the solar panel other than the voltage acquisition target) can be specified.

  In the abnormality detection device according to one aspect of the present invention, the abnormality detection unit is configured such that the voltage acquired by the acquisition unit is equal to or higher than the first threshold and the voltage is equal to or higher than the first threshold. If it is not continued for a predetermined time or more, a shade for a solar panel other than the at least one solar panel in the string is detected.

  According to this configuration, the state of the string can be determined using the fact that a plurality of strings are connected in parallel. For example, when the voltage of a solar panel including an abnormality or a shadow decreases, the voltages of other solar panels in the same string increase. Therefore, based on the fact that the voltage of the solar panel from which the voltage is acquired is relatively high, it can be determined that the solar panel other than the acquisition target has an abnormality or a shadow. In addition, when a shadow is applied to the solar panel, it is possible to determine the presence or absence of a shadow by using the fact that there are many voltage fluctuations over time. Further, the approximate position of the shaded solar panel (here, the solar panel other than the voltage acquisition target) can be specified.

  In the abnormality detection device of one aspect of the present invention, the acquisition unit acquires information on the voltage of at least one solar panel in the string a plurality of times, and the abnormality detection unit detects that the voltage is equal to or higher than the first threshold value. Is detected more than once in a predetermined period, an abnormality of a solar panel other than the at least one solar panel in the string is detected.

  According to this configuration, the state of the string can be determined using the fact that a plurality of strings are connected in parallel. For example, when the voltage of a solar panel including an abnormality or a shadow decreases, the voltages of other solar panels in the same string increase. Therefore, based on the fact that the voltage of the solar panel from which the voltage is acquired is relatively high, it can be determined that the solar panel other than the acquisition target has an abnormality or a shadow. Moreover, the presence or absence of abnormality can be determined using the fact that the number of times that the voltage becomes equal to or higher than the first threshold is large. Moreover, the approximate position of the solar panel having an abnormality (here, the solar panel other than the voltage acquisition target) can be specified.

  In the abnormality detection device according to one aspect of the present invention, the abnormality detection unit detects an abnormality of the string when a voltage applied to the part is equal to or lower than a second threshold value that is smaller than the first threshold value.

  According to this configuration, the abnormality of the string can be detected in consideration of the fact that the bypass diode operates in the solar panel where the abnormality has occurred and the voltage of the solar panel decreases.

  In the abnormality detection device of one aspect of the present invention, the acquisition unit acquires information on the voltage of at least one solar panel in the string, and the abnormality detection unit receives the voltage acquired by the acquisition unit as the first voltage. When the state where the voltage is equal to or lower than the threshold value 2 and the voltage is equal to or lower than the second threshold value continues for a predetermined time or longer, an abnormality of the at least one solar panel is detected.

  According to this configuration, it is possible to determine that there is an abnormality in the solar panel from which the voltage is to be acquired, using the fact that there is little time variation of the voltage. In addition, the approximate position of the abnormal solar panel (here, the solar panel from which the voltage is to be acquired) can be specified.

  In the abnormality detection device according to one aspect of the present invention, the abnormality detection unit is configured such that the voltage acquired by the acquisition unit is less than or equal to the second threshold and the voltage is less than or equal to the second threshold. If it is not continued for a predetermined time or more, a shade for the at least one solar panel is detected.

  According to this configuration, it is possible to determine that the solar panel from which the voltage is to be acquired is shaded by using the time variation of the voltage. Moreover, the approximate position of the shaded solar panel (here, the solar panel from which the voltage is to be acquired) can be specified.

  In the abnormality detection device of one aspect of the present invention, the acquisition unit acquires information on the voltage of at least one solar panel in the string a plurality of times, and the abnormality detection unit detects that the voltage is equal to or less than the second threshold value. Is detected more than once in a predetermined period, an abnormality of the at least one solar panel is detected.

  According to this configuration, it is possible to determine that there is an abnormality in the solar panel from which the voltage is to be acquired, using the fact that the number of times that the voltage is equal to or lower than the second threshold is large. In addition, the approximate position of the abnormal solar panel (here, the solar panel from which the voltage is to be acquired) can be specified.

  The abnormality detection device according to one aspect of the present invention includes a threshold deriving unit that derives the first threshold or the second threshold.

  According to this configuration, it is possible to change the detection criterion for the presence or absence of abnormality of the string by using the first threshold value or the second threshold value as a variable value. Therefore, the presence or absence of an abnormality can be detected according to a desired detection criterion, and maintainability can be improved according to the user's intention.

  In the abnormality detection device of one aspect of the present invention, the threshold deriving unit is configured to use the first threshold or the second threshold based on the voltage at the maximum power operating point of the solar panel from which the voltage is acquired by the acquiring unit. A threshold is derived.

  According to this configuration, since the maximum power operating point (MPP) is used, it is possible to set a threshold value suitable for detecting an abnormality when each solar panel in the string operates at the maximum power operating point.

  In the abnormality detection device according to one aspect of the present invention, the threshold value deriving unit has a past performance value in the same time zone as the time zone in which the voltage was obtained, of the voltage of the solar panel from which the voltage was obtained by the obtaining unit. Based on the above, the first threshold value or the second threshold value is derived.

  According to this configuration, a threshold value suitable for detecting an abnormality of the solar panel can be set from the past voltage tendency of the solar panel from which the voltage is to be acquired.

  In the abnormality detection device of one aspect of the present invention, the threshold deriving unit derives the first threshold or the second threshold based on a voltage applied to a part of a string other than the string.

  According to this configuration, a threshold suitable for detecting an abnormality can be set using the voltage of the solar panel in another string.

  In the abnormality detection device according to one aspect of the present invention, the threshold deriving unit derives the first threshold or the second threshold based on an average value of voltages applied to some of a plurality of other strings.

  According to this configuration, it is possible to set a threshold value suitable for detecting an abnormality by reducing the bias due to the characteristics of the solar panel in each of the other strings.

  In the abnormality detection device of one aspect of the present invention, the threshold deriving unit detects the number of bypass diodes included in each solar panel, the number of solar panels included in the string, and the voltage of the solar panel. The first threshold value or the second threshold value is derived based on at least one of the number of the solar panels to which the voltage detection device is connected.

  According to this configuration, for example, a more accurate threshold can be set according to the solar panel characteristics, the string characteristics, and the connection form between the solar panel from which the voltage is acquired and the voltage detection device.

  The abnormality detection system of one embodiment of the present invention includes a solar cell array in which a plurality of strings in which a plurality of solar panels are connected in series are connected in parallel, and a voltage applied to a part of the strings in the solar cell array. A voltage detection device for detecting the voltage, and an abnormality detection device for acquiring information on the voltage from the voltage detection device and detecting an abnormality of the string when a voltage applied to the part is equal to or higher than a first threshold value. Prepare.

  According to this configuration, the abnormality of the string can be detected by using the increase in the voltage of the solar panel from which the voltage is acquired. Further, the abnormality of the string can be detected by using the voltage applied to a part of the string instead of the voltage of the entire string. Therefore, in an environment where a plurality of strings are connected in parallel, the accuracy of string abnormality detection by voltage can be improved. Further, it is possible to determine whether or not there is an abnormality in the string without connecting a current detection component (for example, a shunt resistor) in series with the string. Therefore, the failure of a component for current detection breaks the string, and it is possible to suppress the loss of power generation opportunities by the photovoltaic power generation panel of the string.

  Moreover, the abnormality detection method of 1 aspect of this invention is in the abnormality detection apparatus which detects the abnormality of the at least 1 string in the solar cell array in which the several string with which the several solar panel was connected in series was connected in parallel. A method for detecting an abnormality, comprising: obtaining information on a voltage applied to a part of the string; and detecting an abnormality of the string when the voltage applied to the part is equal to or higher than a first threshold. Have.

  According to this method, the abnormality of the string can be detected by utilizing the increase in the voltage of the solar panel from which the voltage is acquired. Further, the abnormality of the string can be detected by using the voltage applied to a part of the string instead of the voltage of the entire string. Therefore, in an environment where a plurality of strings are connected in parallel, the accuracy of string abnormality detection by voltage can be improved. Further, it is possible to determine whether or not there is an abnormality in the string without connecting a current detection component (for example, a shunt resistor) in series with the string. Therefore, the failure of a component for current detection breaks the string, and it is possible to suppress the loss of power generation opportunities by the photovoltaic power generation panel of the string.

  The present invention is useful for an anomaly detection device, an anomaly detection system, an anomaly detection method, and the like that can improve the detection accuracy of anomaly detection in strings.

100 PV system 10, 10A1, 10A2, 10A3, 10A4, 10A5 PV panel 10B1, 10B2, 10B3, 10B4, 10B5 PV panel 10C1, 10C2, 10C3, 10C4, 10C5 PV panel 10D1, 10D2, 10D3, 10D4, 10D5 PV panel 10AR PV array 10C PV cell 10G, 10G1, 10G2, 10G3 PV cluster 10ST, 10ST1, 10ST2, 10ST3, 10ST4 PV string 15 Junction box 20 Slave unit 21 DC / DC converter 22 Voltage regulator 26 CPU
27 Communication section 28 Input terminal 29, 29a, 29b Output terminal 30 Repeater 40 Master unit 50 Junction box 60 PCS
DESCRIPTION OF SYMBOLS 70 Monitor terminal 71 Communication part 72 Control part 73 Storage part 74 Operation part 75 Display part 80 Data logger 81 Communication part 82 Control part 83 Storage part 85 Abnormality detection part 86 Threshold value derivation part 90 Monitor server BD, BD1, BD2, BD3 Bypass diode PL power line NW network

Claims (16)

An abnormality detection device that detects an abnormality of at least one string in a solar cell array in which a plurality of strings in which a plurality of solar panels are connected in series are connected in parallel,
An acquisition unit for acquiring information on a voltage applied to a part of the string;
When the voltage applied to the part is equal to or higher than a first threshold, an abnormality detection unit that detects abnormality of the string;
An abnormality detection device comprising: The abnormality detection apparatus according to claim 1,
The acquisition unit acquires voltage information of at least one solar panel in the string,
When the voltage acquired by the acquisition unit is equal to or higher than the first threshold and the state where the voltage is equal to or higher than the first threshold is continued for a predetermined time or more, the abnormality detection unit An abnormality detection device that detects an abnormality of a solar panel other than at least one solar panel. The abnormality detection apparatus according to claim 2,
When the voltage acquired by the acquisition unit is equal to or higher than the first threshold and the state where the voltage is equal to or higher than the first threshold is not continued for the predetermined time or longer, the abnormality detection unit An anomaly detection device for detecting a shade for a solar panel other than the at least one solar panel. The abnormality detection apparatus according to claim 1,
The acquisition unit acquires voltage information of at least one solar panel in the string a plurality of times,
The abnormality detection unit detects an abnormality of a solar panel other than the at least one solar panel in the string when a state where the voltage is equal to or higher than the first threshold is detected a plurality of times in a predetermined period. Anomaly detection device. The abnormality detection device according to any one of claims 1 to 4,
The abnormality detection device detects an abnormality of the string when the voltage applied to the part is equal to or lower than a second threshold value that is smaller than the first threshold value. The abnormality detection device according to claim 5,
The acquisition unit acquires voltage information of at least one solar panel in the string,
When the voltage acquired by the acquisition unit is equal to or lower than the second threshold and the voltage is equal to or lower than the second threshold, the abnormality detection unit is configured to perform the at least one An anomaly detection device that detects anomalies in solar panels. The abnormality detection device according to claim 6,
When the voltage acquired by the acquisition unit is equal to or lower than the second threshold and the state where the voltage is equal to or lower than the second threshold is not continued for the predetermined time or more, the abnormality detection unit An anomaly detection device that detects a shade for one solar panel. The abnormality detection device according to claim 5,
The acquisition unit acquires voltage information of at least one solar panel in the string a plurality of times,
The abnormality detection unit detects an abnormality of the at least one solar panel when a state where the voltage is equal to or lower than the second threshold is detected a plurality of times in a predetermined period. The abnormality detection device according to any one of claims 5 to 8, further comprising:
An abnormality detection device comprising a threshold value deriving unit for deriving the first threshold value or the second threshold value. The abnormality detection device according to claim 9,
The abnormality deriving device, wherein the threshold deriving unit derives the first threshold or the second threshold based on a voltage at a maximum power operating point of the solar panel from which the voltage is obtained by the obtaining unit. The abnormality detection device according to claim 9,
The threshold deriving unit is based on a past actual value of the voltage of the solar panel from which the voltage is acquired by the acquiring unit in the same time zone as the time zone in which the voltage is acquired. An abnormality detection device for deriving a second threshold value. The abnormality detection device according to claim 9,
The threshold deriving unit is an abnormality detection device that derives the first threshold or the second threshold based on a voltage applied to a part of a string other than the string. The abnormality detection device according to claim 12,
The threshold value derivation unit is an abnormality detection device that derives the first threshold value or the second threshold value based on an average value of voltages applied to a part of a plurality of other strings. An abnormality detection device according to any one of claims 9 to 13,
The threshold value deriving unit is connected to a voltage detection device that detects the number of bypass diodes of each solar panel, the number of solar panels included in the string, and the voltage of the solar panel. An abnormality detection device that derives the first threshold value or the second threshold value based on at least one of the number of A solar cell array in which a plurality of strings in which a plurality of solar panels are connected in series are connected in parallel;
A voltage detection device for detecting a voltage applied to a part of the string in the solar cell array;
An abnormality detection device that acquires information on the voltage from the voltage detection device and detects abnormality of the string when the voltage applied to the part is equal to or higher than a first threshold;
An abnormality detection system comprising: An abnormality detection method in an abnormality detection device for detecting an abnormality of at least one string in a solar cell array in which a plurality of strings in which a plurality of solar panels are connected in series are connected in parallel,
Obtaining voltage information across a portion of the string;
If the voltage across the portion is greater than or equal to a first threshold, detecting an abnormality in the string;
An abnormality detection method comprising:

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