JP6520771B2 - Failure detection device for solar cell and solar power generation system - Google Patents

Description

  The present invention relates to a failure detection device for a solar cell used in a solar power generation system and a solar power generation system.

  Conventionally, in a solar power generation system, electric power generated by a solar cell string (solar cell) is converted to electric power via a power conditioning system (hereinafter simply referred to as a PCS (Power Conditioning System)) including a DC-AC converter and the like. It is supplied to the grid.

  A solar cell string may cause various failures and failures during operation, and in order to maintain good operating conditions, these failures and failures must be dealt with promptly. For this purpose, conventionally, as described in, for example, Patent Documents 1 to 3, the IV curve of the solar cell string is monitored, and the shape of the IV curve causes various defects or failures in the solar cell string. The occurrence has been detected. In addition, when a fault or failure occurs in the solar cell string, for example, the content is notified to the management device of the solar power generation system, and a worker who confirms the notification content rushes to the solar cell string, and the fault or failure Dealing with.

Unexamined-Japanese-Patent No. 2007-311487 JP 2012-156343 A Unexamined-Japanese-Patent No. 2006-201827 JP, 2013-156125, A Patent No. 5196607 gazette Patent No. 4604250

  Among the defects and failures of the solar cell string, there are some that can be determined by the worker visually observing the appearance such as discoloration of the solar battery panel. However, a disconnection failure such as a cable disconnection or a soldering failure of a solar cell panel can not be easily determined visually by visual observation. For this reason, even if the worker receives a notification of a defect or failure and rushes in when there is a disconnection failure in the solar cell string, it takes a long time to specify the position of the disconnection failure. have.

  Therefore, the present invention aims to provide a solar cell failure detection device and a solar power generation system capable of reducing the burden on the worker when the solar cell has a failure and the failure is a disconnection failure. And

  In order to solve the above problems, the failure detection device for a solar cell according to the present invention includes a current measurement unit that measures an output current of the solar cell, and a voltage measurement unit that measures a voltage between positive and negative output terminals of the solar cell. And an IV characteristic acquisition unit that acquires an IV characteristic of the solar cell based on a measurement value by the current measurement unit and a measurement value by the voltage measurement unit, and the IV characteristic acquisition unit acquires A failure determination unit that determines the presence or absence of a disconnection failure in the solar cell based on IV characteristics, a failure position detection unit that detects a disconnection failure position of the solar battery, and the failure determination unit determines that there is a disconnection failure In this case, the control unit is configured to perform a disconnection position detection operation of the solar cell in which a disconnection failure has occurred by the failure position detection unit.

  According to said structure, an IV characteristic acquisition part acquires the IV characteristic of a solar cell based on the measured value by an electric current measurement part, and the measured value by a voltage measurement part. The failure determination unit determines the presence or absence of a disconnection failure in the solar cell based on the IV characteristic acquired by the IV characteristic acquisition unit. When the failure determination unit determines that there is a break in the solar cell, the control unit causes the failure position detection unit to perform the disconnection position detection operation of the solar cell in which the break occurs, and the failure position detection unit Detect the open fault position of.

  Therefore, there is no need for a worker who rushed to the solar cell to receive a notification that a failure has occurred, and when the failure is a disconnection failure, there is no need to perform the work of detecting the disconnection position, and the burden on the worker can be reduced. .

  In the above-described solar cell failure detection device, the solar cell is a solar cell string, and a plurality of the solar cell strings are connected to a multi-string power conditioning system to constitute a solar power generation system, An output line for each solar cell string for connecting the solar cell string to the power conditioning system is provided with a backflow prevention diode or an open / close switch, and the control unit is only for the solar cell string in which a disconnection failure occurs. The input of the generated power to the power conditioning system may be stopped, and the failure position detection unit may be configured to perform the disconnection position detection operation.

  According to the above configuration, when the failure position detection unit performs the disconnection position detection operation, the input of the generated power to the power conditioning system is stopped only for the solar cell string in which the disconnection failure occurs. Thereby, it can respond appropriately also to the photovoltaics system provided with the power conditioning system of a multi string method.

  In addition, when there is a solar cell string in which a disconnection failure occurs, only the solar cell string can be shut down and safely disconnected. In addition, since power generation can be continued for a solar cell string that has not been broken, there is no need to stop the operation of the power conditioning system, and a reduction in the amount of power generation due to a solar cell string failure can be minimized.

  In the above-mentioned failure detection device for solar cells, an output line for each of the solar cell strings for connecting a plurality of the solar cell strings to the power conditioning system is provided with a backflow prevention diode respectively, and in the disconnection position detection operation The signal output from the failure position detection unit to the solar cell may be set to a voltage equal to or less than the forward voltage of the backflow prevention diode.

  According to the above configuration, the signal output from the failure position detection unit to the solar cell in the disconnection position detection operation is set to a voltage equal to or less than the forward voltage of the backflow prevention diode. The signal output from the position detection unit to the solar cell is set to a voltage equal to or less than the forward voltage of the backflow prevention diode. Therefore, the output line of each of the solar cell strings connecting the plurality of solar cell strings to the power conditioning system can be provided with a backflow prevention diode instead of the open / close switch. Thereby, the backflow prevention function to a solar cell can be provided, suppressing the increase in a number of parts.

  In the above-mentioned failure detection device for solar cells, the control unit may notify the management device of the photovoltaic power generation system of the determination result by the failure determination unit and the detection result by the failure position detection unit.

  According to the above configuration, since the determination result by the failure determination unit of the failure detection device and the detection result by the failure position detection unit are notified to the management device, the worker can detect the failure when a failure occurs in the solar cell. The type of failure of the solar cell notified from the device to the management device, and the disconnection position in the case where the disconnection failure occurs in the solar cell can be confirmed by the management device.

  A photovoltaic power generation system according to the present invention includes any of the above-described failure detection device for a solar cell, a solar cell, a power conditioning system to which the solar cell is connected, and a management device that communicates with the control unit. Configuration.

  According to said structure, the effect by the failure detection apparatus of any one of said solar cells is exhibited.

  According to the configuration of the present invention, it is not necessary for the worker who rushed to the solar cell to be notified of the occurrence of the failure to perform the work of detecting the disconnection position when the failure is the disconnection failure, and the burden on the operator Can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS It is a general | schematic circuit diagram which shows the structure of the solar power generation system provided with the failure detection apparatus of the solar cell of embodiment of this invention. It is an equivalent circuit of the solar cell string shown in FIG. It is a graph which shows the IV curve at the time of the normal time in a solar cell string, and various failure generation which an IV characteristic acquisition part of PCS shown in Drawing 1 acquires. (A) of FIG. 4 is a graph which shows the IV curve of Rs increase mode (solid line, Vpm fall) and normal time (broken line) in the solar cell string shown in FIG. (B) of FIG. 4 is a graph showing an I-V curve in the Voc reduction mode (solid line) and in the normal state (broken line). (C) of FIG. 4 is a graph which shows an IV curve in Rsh reduction mode (solid line, Ipm decrease) and normal time (broken line). (D) of FIG. 4 is a graph showing an I-V curve in the Isc reduction mode (solid line) and in the normal state (broken line). (E) of FIG. 4 is a graph showing an IV curve when the series resistance Rs of the solar cell string is changed (solid line, step generation) and in a normal state (broken line). (F) of FIG. 4 is a figure which shows the case (No output) which cable disconnection generate | occur | produces and it can not draw an IV curve. It is a flowchart which shows operation | movement of the failure detection apparatus shown in FIG. It is a general | schematic circuit diagram which shows the structure of the solar energy power generation system provided with the failure detection apparatus of the solar cell of other embodiment of this invention. It is a schematic circuit diagram which shows the modification of the solar energy power generation system provided with the failure detection apparatus of the solar cell shown in FIG. FIG. 8 is an explanatory view showing a flow direction of a fault position detection signal outputted by a fault position detection unit in the disconnection position detection operation of the solar cell string in the solar cell string shown in FIG. 7; It is a graph which shows the forward voltage of the backflow prevention diode shown in FIG.

Embodiment 1
Embodiments of the present invention will be described below based on the drawings. FIG. 1 is a schematic circuit diagram showing a configuration of a photovoltaic power generation system provided with the failure detection apparatus for a solar cell according to the present embodiment.

(Configuration of photovoltaic system)
As shown in FIG. 1, the photovoltaic power generation system 1 includes a plurality of solar cell strings (solar cells) 11, a changeover switch 12, a connection box 13, an open / close switch 14, and a power conditioning system (hereinafter referred to as PCS (Power Conditioning System)). And a failure position detection device 2 and a server (management device) 19.

  The solar cell string 11 is formed by connecting a number of solar cell modules 21 in series. Each solar cell module 21 includes a plurality of solar cells (not shown) connected in series, and is formed in a panel shape. Each solar cell string 11 is connected to the junction box 13 via the N-side output line 22 a and the P-side output line 23 a.

  A PV current measurement circuit (current measurement unit) 31 is provided on, for example, the output line 22a of each solar cell string 11, and a PV voltage measurement circuit (voltage measurement unit) 32 is provided between the output line 22a and the output line 23a. Is provided. The PV current measurement circuit 31 measures the output current of the solar cell string 11 and measures the output voltage of the PV voltage measurement circuit 32. Although FIG. 1 shows the configuration in which the PV current measurement circuit 31 and the PV voltage measurement circuit 32 are provided only in one solar cell string 11 for simplification, they are provided in each solar cell string 11 . Alternatively, only one pair of the PV current measurement circuit 31 and the PV voltage measurement circuit 32 is provided, and when measuring each solar cell string 11, the pair of PV current measurement circuit 31 and the PV voltage measurement circuit 32 are switched and used. May be

  The changeover switch 12 is provided on a pair of output lines 22 a and 23 a between each solar cell string 11 and the connection box 13. The changeover switch 12 is, for example, a changeover relay, and is configured to switch the connection destination of each solar cell string 11 between the connection box 13 and the failure position detection unit 16 of the failure detection device 2.

  The connection box 13 connects the respective solar cell strings 11 in parallel to each other, and is connected to the PCS 15 by a pair of output lines 22 and 23. A backflow prevention diode 24 is provided in the connection box 13 for each solar cell string 11. The backflow prevention diode 24 prevents current from flowing in the opposite direction to the current supplied by the solar cell string 11. The backflow prevention diode 24 may be provided on any of the output lines 22a and 23a. Moreover, although the backflow prevention diode 24 is arrange | positioned to the electric power line 23a in the example of FIG. 1, you may arrange | position to the electric power line 22a. In this case, the anode is connected to the PCS 15 and the cathode is connected to the solar cell string 11.

  The open / close switch 14 is controlled by the PCS 15 to open and close the solar cell string 11 from the PCS 15 by the open operation.

  The PCS 15 converts direct current power input from the solar cell string 11 into alternating current power, and outputs the alternating current power to the alternating current grid 18. The PCS 15 includes an I-V characteristic acquisition unit 25, a failure determination unit 26, and a control unit 27. Each of these units is configured by, for example, a microcomputer.

(Configuration of failure detection device)
The failure detection device 2 includes the changeover switch 12, the failure position detection unit 16, the display unit 17, and the PV current measurement circuit in addition to the IV characteristic acquisition unit 25, the failure determination unit 26, and the control unit 27 provided in the PCS 15. 31 and a PV voltage measurement circuit 32.

  The IV characteristic acquisition unit 25 determines each solar cell string 11 based on the output current of the solar cell string 11 measured by the PV current measurement circuit 31 and the output voltage of the solar cell string 11 measured by the PV voltage measurement circuit 32. To obtain the I-V characteristics of In this case, the IV characteristic acquisition unit 25 creates an IV curve of the solar cell string 11 based on the output current of the solar cell string 11 and the output voltage of the solar cell string 11.

  The failure determination unit 26 determines the presence or absence of the problem of the IV characteristic of each solar cell string 11 acquired by the IV characteristic acquisition unit 25. That is, the IV characteristic acquisition unit 25 determines the presence or absence of a failure (including a defect) in each solar cell string 11 based on the IV characteristic of each solar cell string 11. When it is determined that there is a failure in any of the solar cell strings 11, the failure determination unit 26 determines the type of failure of the solar cell string 11, that is, the failure mode.

  The control unit 27 notifies the server 19 of the solar power generation system 1 of the determination result of the failure determination unit 26. Further, when the failure determination unit 26 determines that there is a disconnection failure in any of the solar cell strings 11, the control unit 27 notifies the failure position detection unit 16 to that effect and detects the disconnection position in the failure position detection unit 16 The operation is performed and the open / close switch 14 is opened. Furthermore, the control unit 27 notifies the server 19 of the detection result of the failure determination unit 26.

  The failure position detection unit 16 receives the notification from the control unit 27, detects the position of the disconnection failure in the solar cell string 11 in which the disconnection failure occurs, and causes the display unit 17 to display the detection result. Specifically, for example, information for identifying the solar cell string 11 in which the disconnection failure occurs and information for identifying the disconnection failure position are displayed on the display unit 17. The fault position detection unit 16 further transmits the information displayed on the display unit 17 to the control unit 27.

  Here, an example of the I-V curve which the I-V characteristic acquisition part 25 produces is demonstrated. FIG. 2 is an equivalent circuit of the solar cell string 11 shown in FIG. FIG. 3 is a graph showing an I-V curve in the normal state of the solar cell string 11 and in the occurrence of various failures, which is acquired by the I-V characteristic acquisition unit 25 of the PCS 15.

  As shown in FIG. 3, when the solar cell string 11 fails, the IV curve changes with respect to the normal IV curve according to the type of failure. Therefore, the failure determination unit 26 can determine the presence or absence of a failure occurrence in the solar cell string 11 and the type of failure (failure condition) at the occurrence of the failure by observing the IV curve.

  In FIG. 3, the Voc reduction mode assumes a drop in the open circuit voltage Voc of the solar cell string 11 due to disconnection of a circuit in the solar cell module 21 of the solar cell string 11 or deterioration with age. This mode is characterized in that the voltage corresponding to the current drops uniformly.

  The Isc reduction mode assumes a reduction in the short circuit current Isc of the solar cell string 11 due to yellowing of the solar cell module 21 or exfoliation of the interface between the solar cell and the filler. This mode is characterized in that the current corresponding to the voltage drops uniformly.

  The Rs increase mode assumes an increase in series resistance Rs of the solar cell string 11 due to corrosion of a terminal or a hot spot. This mode is characterized in that the voltage drop corresponding to the current is not uniform, and the voltage drop is large particularly when the current is high.

  The Rsh reduction mode assumes a change in water content in the encapsulant of the solar cell module 21 and a decrease in parallel resistance of the solar cell string 11 due to an increase in leakage current. This mode is characterized in that the current drop corresponding to the voltage is not uniform, and the current drop is large particularly when the voltage is high.

  (A) of FIG. 4 is a graph which shows the IV curve in Rs increase mode (solid line, Vpm fall) and normal time (broken line). (B) of FIG. 4 is a graph showing an I-V curve in the Voc reduction mode (solid line) and in the normal state (broken line). (C) of FIG. 4 is a graph which shows an IV curve in Rsh reduction mode (solid line, Ipm decrease) and normal time (broken line). (D) of FIG. 4 is a graph showing an I-V curve in the Isc reduction mode (solid line) and in the normal state (broken line). (E) of FIG. 4 is a graph showing an IV curve when the series resistance Rs of the solar cell string 11 is changed (solid line, step generation) and in a normal state (broken line). (F) of FIG. 4 is a figure in case a cable disconnection arises and it can not draw an IV curve (no output).

  Among the above, the Voc reduction mode shown in (b) of FIG. 4 corresponds to the case of a cluster disconnection, and the state without output shown in (f) of FIG. 4 corresponds to a cable disconnection. Therefore, failure determination unit 26 determines these states as disconnection failure of solar cell string 11.

  When the IV curve has a normal (reference) shape, the fault determination unit 26 determines that the IV characteristic is normal (no problem), that is, the solar cell string 11 has no fault. On the other hand, when the IV curve is different from the shape of the normal (reference) curve, the fault determination unit 26 determines that the IV characteristic is abnormal, that is, the solar cell string 11 has a fault. In this case, the failure determination unit 26 determines the corresponding failure from the IV curve.

(Configuration of fault position detection unit)
The failure position detection unit 16 detects a disconnection failure of the solar cell string 11 such as a cluster disconnection of the solar cell string 11 or a cable disconnection. The failure position detection unit 16 has a conventionally known configuration for detecting a disconnection failure of the solar cell string 11. These are based on, for example, a so-called TDR (time domain reflectance) method or a ground capacity method. As the TDR method, the techniques disclosed in Patent Documents 4 and 5 can be used, and as the ground capacity method, the technique disclosed in Patent Document 6 can be used.

  When detecting the open failure position of the solar cell string 11, the failure position detection unit 16 causes the display unit 17 to display the result and transmits the result to the control unit 27.

(Operation of failure detection device)
In the above configuration, the operation of the failure detection device 2 will be described below. FIG. 5 is a flowchart showing the operation of the failure detection device 2.

  The IV characteristic acquisition unit 25 of the failure detection device 2 is based on the output current of the solar cell string 11 measured by the PV current measurement circuit 31 and the output voltage of the solar cell string 11 measured by the PV voltage measurement circuit 32. The IV characteristic of each solar cell string 11 is acquired (S11).

  Next, the failure determination unit 26 determines the presence or absence (presence or absence of a failure including a defect) of the IV characteristic of each solar cell string 11 acquired by the IV characteristic acquisition unit 25 (S12). If there is no problem in the IV characteristic of each solar cell string 11 as a result of the determination in S12, the control unit 27 notifies that effect to the server 19 of the photovoltaic system 1 (S17).

  On the other hand, if any of the solar cell strings 11 has a problem with the IV characteristics as a result of the judgment in S12, that is, if the failure judgment unit 26 has a problem with the IV characteristics, the broken solar cell string 11. The type of failure (failure mode) is determined (S13).

  If the type of failure of the solar cell string 11 is other than the disconnection failure as a result of the determination in S13, the control unit 27 determines the failure state (failure mode) of the failed solar cell string 11 of the photovoltaic power generation system 1 The server 19 is notified (S18).

  Further, if the type (fault mode) of the failure of the failing solar cell string 11 is a disconnection failure in the determination result of S13, the control unit 27 causes the open / close switch 14 to be opened and the solar cell string 11 to be PCS15. Then, the failure position detection unit 16 performs the disconnection position detection operation (S14). In this case, the PCS 15 stops its operation.

  Next, the failure position detection unit 16 detects the disconnection position of the broken solar cell string 11 by the disconnection position detection operation (S15). In this case, the failure position detection unit 16 switches the changeover switch 12 so that the broken solar cell string 11 is connected to the failure position detection unit 16.

  The failure position detection unit 16 transmits the detection result to the control unit 27 when it detects the disconnection position of the photovoltaic string 11 having a disconnection failure. The control unit 27 receives the detection result of the failure position detection unit 16 and outputs information indicating the broken solar cell string 11 and information indicating the broken position of the solar cell string 11 to the server of the solar power generation system 1 19 is notified (S16).

  A worker stands by at the server 19 of the photovoltaic system 1. Alternatively, the failure status of the solar cell string 11 is notified from the server 19 to the worker. Thereby, the worker can cope with the failure of the solar cell string 11.

(Advantage of failure detection device)
In the failure detection device 2, the failure determination unit 26 determines the presence or absence of a failure of the solar cell string 11 based on the IV characteristic acquired by the IV characteristic acquisition unit 25, and the failure position detection unit 16 determines the failure. When the unit 26 indicates the determination result that the solar cell string 11 is broken, the broken position is detected.

  Therefore, there is no need for the worker who rushed to the solar cell string 11 to receive the notification that a failure has occurred, and when the failure is a disconnection failure, there is no need to perform the work of detecting the disconnection position, and the burden on the worker is reduced. Can.

  Further, since the failure detection device 2 is configured using the IV characteristic acquisition function (IV characteristic acquisition unit 25) generally provided in the PCS 15, the configuration can be simplified.

(Modification 1)
Although the failure detection device 2 illustrated in FIG. 1 has a configuration in which the IV characteristic acquisition unit 25, the failure determination unit 26, and the control unit 27 are provided in the PCS 15, the present invention is not limited thereto. That is, all or part of the IV characteristic acquisition unit 25, the failure determination unit 26 and the control unit 27 may be provided outside the PCS 15. Further, the IV characteristic acquisition unit 25, the failure determination unit 26, and the control unit 27 may be configured by an IV tester provided separately from the PCS 15 and having these functions. The configuration of this modification is similarly applicable to the failure detection device 2 of the other embodiments.

Second Embodiment
Other embodiments of the present invention will be described below based on the drawings. In addition, about the member which has the same function as the member demonstrated in the said embodiment for convenience of explanation, the same code | symbol is appended and the description is abbreviate | omitted. FIG. 6 is a schematic circuit diagram showing the configuration of a photovoltaic power generation system provided with the failure detection apparatus for a solar cell according to the present embodiment.

(Configuration of photovoltaic power generation system and configuration of failure detection device)
As shown in FIG. 6, the solar power generation system 1 of this embodiment includes a multi-string PCS (hereinafter referred to as multi-string PCS) 51 instead of the PCS 15 shown in FIG. And a failure detection device 3 is provided instead of.

  As shown in FIG. 6, the multi-string PCS 51 includes a DC / AC conversion unit 52 and a DC / DC conversion unit 53. The DC / AC conversion unit 52 converts DC power into AC power and outputs the AC power to the AC power system 18.

  The DC / DC conversion unit 53 is provided for each of the plurality of solar cell strings 11 and boosts the DC power input from the solar cell strings 11. The output sides of the DC / DC conversion units 53 are connected in parallel to each other, and are connected to the DC / AC conversion unit 52. The output lines 22 a and 23 a of the corresponding solar cell string 11 are connected to the input side of each DC / DC conversion unit 53 via the open / close switch 54. The open / close switch 54 performs an open / close operation for each of the output lines 22 a and 23 a, and the open / close operation is controlled by the control unit 27. The DC / DC conversion unit 53 is provided with the IV characteristic acquisition unit 25, the failure determination unit 26, and the control unit 27. In FIG. 6, for convenience, although the IV characteristic acquisition unit 25, the failure determination unit 26, and the control unit 27 are provided in only one DC / DC conversion unit 53, other DCs are shown. The same applies to the / DC converter 53.

(Operation and advantages of failure detection device)
In the failure detection device 3 of the present embodiment, as in the failure detection device 2 of the above-described embodiment, the failure position detection unit 16 detects the disconnection position for the solar cell string 11 determined as having a disconnection failure by the failure determination unit 26. . In this case, the control unit 27 opens the open / close switch 54 corresponding to the solar cell string 11 in which the disconnection failure occurs, and disconnects only the solar cell string 11 in which the disconnection failure occurs from the multistring PCS 51. The disconnection position detection operation is performed by the failure position detection unit 16. Further, in the DC / DC conversion unit 53, only the DC / DC conversion unit 53 corresponding to the broken solar cell string 11 stops operation. As a result, the failure detection device 3 can appropriately cope with the photovoltaic power generation system 1 provided with the multi-string power conditioning system.

In addition, when there is a solar cell string 11 in which a disconnection failure occurs, only the solar cell string 11 can be shut down and safely disconnected. In addition, since power generation can be continued for the solar cell string 11 that does not cause a disconnection failure, there is no need to stop the operation of the failure occurring solar cell module 51, and the reduction of the power generation amount due to the failure of the solar cell string 11 is minimized. It can be suppressed. The other operations and advantages of the failure detection device 3 are the same as those of the failure detection device 2.
(Modification 2)
The modification of the solar power generation system shown in FIG. 6 is demonstrated below based on drawing. In addition, about the member which has the same function as the member demonstrated in the said embodiment for convenience of explanation, the same code | symbol is appended and the description is abbreviate | omitted.

  FIG. 7 is a schematic circuit diagram showing a modification of the solar power generation system provided with the failure detection apparatus for a solar cell shown in FIG. FIG. 8 is an explanatory view showing a flow direction of a fault position detection signal output from the fault position detection unit 16 in the disconnection position detection operation of the solar cell string 11 in the solar power generation system 1 shown in FIG. FIG. 9 is a graph showing the forward voltage of the backflow prevention diode.

  As shown in FIG. 7, in the solar power generation system 1 provided with the multi-string PCS 51, the backflow prevention diode 24 can be provided instead of the open / close switch 54 shown in FIG. Further, the switch connecting the solar cell string 11 and the failure position detection unit 16 may be a switch 33 with a 2a contact instead of the changeover switch 12.

  In the photovoltaic power generation system 1 shown in FIG. 7, the signal (fault position detection signal) for detecting the break position of the solar cell string 11 output by the fault position detection unit 16 is the forward direction of the backflow prevention diode 24. Set the voltage below the voltage. The forward voltage of the backflow prevention diode 24 is Vf shown in FIG. Thus, in the state where the operation of the DC / DC 53 connected to the broken solar cell string 11 is stopped, the failure position detection signal does not flow to the multistring PCS 51 side as shown in FIG. It flows to the solar cell string 11 side (it shows by a solid line) (it shows by a dashed-two dotted line). Therefore, the failure detection device 3 can detect the disconnection position of the solar cell string 11 without the open / close switch 54, and additionally has a function to prevent the backflow to the solar cell string 11 while suppressing an increase in the number of parts. can do.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 solar power generation system 2 fault detection apparatus 3 fault detection apparatus 11 solar cell string 12 changeover switch 13 connection box 14 opening / closing switch 15 power conditioning system 16 fault position detection unit 19 server (management apparatus)
21 solar cell module 22, 23 output line 22a, 23a output line 24 backflow prevention diode 25 IV characteristic acquisition unit 26 failure determination unit 27 control unit 31 PV current measurement circuit (current measurement unit)
32 PV Voltage Measurement Circuit (Voltage Measurement Unit)
33 switch 51 multi-string power conditioning system 52 DC / AC converter 53 DC / DC converter 54 open / close switch

Claims (4)

A current measurement unit that measures the output current of the solar cell;
A voltage measurement unit that measures a voltage between positive and negative output terminals of the solar cell;
An IV characteristic acquisition unit that acquires an IV characteristic of the solar cell based on a measurement value by the current measurement unit and a measurement value by the voltage measurement unit;
A failure determination unit that determines the presence or absence of a disconnection failure in the solar cell based on the IV characteristic acquired by the IV characteristic acquisition unit;
A failure position detection unit that detects a disconnection failure position of the solar cell;
And a control unit for performing a disconnection position detection operation of a solar cell in which a disconnection failure has occurred by the failure position detection unit, when the failure determination unit determines that there is a disconnection failure .
The solar cell is a solar cell string,
A plurality of the solar cell strings are connected to a multi-string power conditioning system to constitute a solar power generation system,
An output line for each of the solar cell strings connecting a plurality of the solar cell strings to the power conditioning system is provided with a backflow prevention diode or an open / close switch, respectively.
The said control part stops the input of the generated power to the said power conditioning system only about the solar cell string which has produced the disconnection failure, The failure detection apparatus of the solar cell which makes the said failure position detection part perform disconnection position detection operation . Each of the output lines for each of the solar cell strings connecting a plurality of the solar cell strings to the power conditioning system is provided with a backflow prevention diode, respectively.
The signal the fault position detection unit in the disconnected point detection operation is output to the solar cell, the failure detection apparatus for the photovoltaic devices according to claim 1, the forward voltage is set to a voltage less than the blocking diode. Wherein the control unit, the malfunction determining unit according to the determination result and the fault location detecting unit according to a detection result failure detecting apparatus for the photovoltaic devices according to claim 1 or 2 notifies the management unit of the solar power generation system. The failure detection apparatus for a solar cell according to any one of claims 1 to 3 ;
With solar cells,
A power conditioning system to which the solar cell is connected;
The solar power generation system provided with the management apparatus which communicates with the said control part.

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