JP6446900B2 - Solar power generation system inspection apparatus and solar power generation system inspection method - Google Patents

Description

  The present invention relates to a solar power generation system inspection apparatus and a solar power generation system inspection method that are provided in a solar power generation system and inspect whether there is an abnormality in the solar power generation system.

  Conventionally, in a photovoltaic power generation system, as shown in Patent Documents 1 and 2, electric power generated by a solar cell is supplied to a power transmission network via a power conditioner including a booster, a DC / AC converter, and the like. It has become so.

  In the photovoltaic power generation system, as shown in FIG. 9A, a plurality of solar cells 101 are connected in series to form a solar cell module (PV module) 102, and a plurality of solar cell modules 102 are further connected in series. A solar cell string 103 is configured by connection.

  In the solar cell module (solar cell panel) 102, when a shadow is formed on a part of the light receiving surface, the solar cell 101 in that part does not generate power. In this case, the solar cell 101 in that portion generates a voltage difference with other solar cells 101 and generates heat by consuming electric power. Therefore, in order to prevent this situation, a bypass diode that bypasses the current flowing through the solar cells 101 is connected to the solar cell module 102 in parallel with the solar cells 101 connected in series.

  Here, as shown in FIG. 9B, a case is assumed in which one solar battery cell 101a fails in the solar battery module 102a. In this case, the current flowing through the solar cell module 102 upstream of the solar cell module 102a bypasses the solar cell module 102a (solar cell 101a, 101) and flows through the bypass diode 104a. Moreover, the solar cell 101a of the solar cell module 102a becomes a resistance component, and the current generated by the solar cell 101 and the solar cell 101a of the solar cell module 102a flows through the resistance component. As described above, as a result of the generated current flowing through the resistance component, heat is generated in the resistance component, and there is a possibility that a failure may spread around.

  Therefore, as shown in Patent Documents 1 and 2, the conventional solar power generation system includes an inspection device that detects a failure of the solar battery cell 101 as described above. In the configurations described in Patent Documents 1 and 2, when the presence or absence of a failure of the solar battery cell 101 is inspected, the IV curve (measured IV curve (measured IV characteristic)) of the solar battery string 103 as shown in FIG. The generated IV curve is compared with the IV curve (reference IV curve) of the normal solar cell string 103 in which the solar cell 101 does not fail. Thereby, the presence or absence (absence or absence of abnormality) of the solar battery cell 101 in the solar battery string 103 is determined.

  FIG. 10 is a graph showing an IV curve (solid line) when the solar cell string 103 is normal and an IV curve (broken line) when the solar cell string 103 includes the failed solar cell 101. In FIG. 10, V indicates an open circuit voltage, and I indicates a short circuit current.

  As shown in FIG. 10, the IV curve in the case where the solar cell string 103 is normal rises to a predetermined current value in a state in which the current is almost vertical from the position where the current is zero, and then the voltage is in a state where the current is almost constant. Becomes a curve that decreases to 0V. On the other hand, the IV curve of the solar battery string 103 including the failed solar battery cell 101 rises from a position where the current is zero, in a state where it lies at a low angle by increasing the current while the voltage drops, After rising up to a predetermined current value in a state close to vertical, the voltage decreases to 0 V while the current is almost constant. Therefore, the presence or absence of failure of the solar battery cell 101 in the solar battery string 103 is determined based on the IV curve (dashed line, measured IV curve) obtained during the inspection and the IV curve (solid line, reference IV curve) when the solar battery string 103 is normal. Can be determined by comparing the slope and shape of the vicinity of the rising portion of the IV curve (current zero) (the skirt portion of the IV curve).

JP 2014-11430 A (published January 20, 2014) JP 2014-38961 A (published February 27, 2014)

  However, in the above conventional configuration, regardless of whether or not the solar cell (solar cell string) is generating electric power, a solar cell (solar cell) is obtained from a current source circuit in which a constant current device and a voltage source device are connected in series. The IV curve is obtained by supplying a constant current to the string. For this reason, it is necessary for the constant current device to always generate a constant current while withstanding a large voltage during an inspection operation during power generation of the solar cell. Therefore, a large element having a large power handling value is required as an element constituting the constant current device. Or when it replaces with a large sized element with a large withstand power value and uses an element with a small withstand power value, it is necessary to provide many elements. In some cases, a heat sink is required. For this reason, there exists a problem that an apparatus becomes large sized.

  Specifically, in the conventional configuration, the current source circuit includes a configuration in which a plurality of constant current diodes are connected in series to a constant voltage source, and a zener diode is connected in parallel to each of the constant current diodes. It is said.

  In this case, in the inspection operation during power generation of the solar cell, the constant current diode needs to control the current by stepping down the total voltage value of the constant voltage source and the generated voltage of the solar cell. Generally, since the withstand voltage of one constant current diode is smaller than the total voltage value, in the above configuration, a plurality of constant current diodes are connected in series to ensure a desired withstand voltage.

  Further, in the above conventional configuration, since a plurality of constant current diodes are connected in series, due to individual variations of the constant current diodes, the voltage is concentrated on the constant current diode having the smallest withstand current value. It can be destroyed. For this reason, each constant current diode is connected in parallel with a zener diode that enters a conduction mode when the voltage exceeds a certain voltage, thereby preventing the voltage from concentrating on one constant current diode.

  Accordingly, an object of the present invention is to provide an inspection apparatus for a photovoltaic power generation system that can reduce a required power-proof value and have a small configuration.

  In order to solve the above-described problem, the inspection apparatus for a photovoltaic power generation system according to the present invention determines the presence or absence of an abnormality in a solar cell by comparing the measured IV property, which is the IV property measured for the solar cell, with the reference IV property In an inspection apparatus for a photovoltaic power generation system including an abnormality presence / absence determination unit, current detection means for detecting an output current of a solar battery, voltage detection means for detecting an output voltage of the solar battery, and the amount of power generated by the solar battery Or an inspection availability determination unit that determines whether or not a change value that is a value that changes according to the amount of power generation is within a range of inspectable values that is less than a maximum value of the change value of the solar cell, and the change An IV characteristic generating means for obtaining the measured IV characteristic from the output current and the output voltage when the value is within the range of the inspectable value is provided.

  According to said structure, the test | inspection availability determination part is a solar cell power generation amount, or the change value which is a value which changes according to the said power generation amount, for example, the power generation amount of a solar cell battery, or the power generation current of a solar cell battery is solar. It is determined whether or not the inspection value is within a range that is smaller than the maximum value of the change value of the battery. The IV characteristic generation means obtains the measured IV characteristic from the output current and output voltage of the solar cell when the change value is within the range of the inspectable value. The abnormality presence / absence determining unit compares the measured IV characteristic with the reference IV characteristic to determine whether the solar cell is abnormal.

  Thereby, the inspection apparatus can reduce the power-proof value required for the configuration for obtaining the measurement IV characteristics, and can have a small configuration.

  In the inspection apparatus for the solar power generation system, the IV characteristic generation unit is provided in the short-circuit current path for short-circuiting the positive electrode and the negative electrode of the solar cell, and the semiconductor that opens and closes the short-circuit current path. A switch, a semiconductor switch control unit for controlling driving of the semiconductor switch so as to obtain the measured IV characteristic in a state of rising from a point of zero current to at least a predetermined current value, and by control of the semiconductor switch control unit It is good also as a structure provided with the production | generation part which calculates | requires the said measurement IV characteristic from the said output current and the said output voltage, or the said output current at the time of the drive of the said semiconductor switch.

  According to the above configuration, in the IV characteristic generation unit, the semiconductor switch control unit controls the driving of the semiconductor switch so that the measured IV characteristic in a state where the current rises from the point of zero current to at least a predetermined current value is obtained. To do.

  Thereby, when calculating | requiring measured IV characteristic, the electric power proof value requested | required of a semiconductor switch can be reduced reliably.

  In the inspection apparatus for a solar power generation system described above, the semiconductor switch is a solid state relay in which an input unit that inputs a drive signal from the semiconductor switch control unit and an open / close operation unit that opens and closes the short-circuit current path are insulated The drive signal may be a PWM signal.

  According to the above configuration, since the short-circuit energization path is opened and closed by the solid state relay, the current flowing through the short-circuit energization path can be made zero or substantially zero when the short-circuit energization path is opened. Thereby, the IV characteristic generation unit can obtain an accurate measurement IV characteristic in which the intersection with the V-axis is strictly zero, and the abnormality presence / absence determination unit can detect the abnormality of the solar cell based on the measurement IV characteristic line. Presence / absence can be accurately determined.

  In the inspection apparatus for a solar power generation system, the short-circuit energization path is provided so as to short-circuit the output line of the solar cell, and the IV characteristic generation unit is based on a connection position of the short-circuit energization path in the output line. Also, an open / close switch provided on the output side for opening and closing the output line may be provided, and the generation unit may obtain the measured IV characteristic after opening the open / close switch.

  According to the above configuration, the generation unit obtains the measurement IV characteristic after opening the open / close switch that opens and closes the output line, and thus can appropriately obtain the measurement IV characteristic.

  In addition, since the inspection device can be provided in the output path of power from the solar cell, the open / close switch, the current detection unit, and the voltage detection unit use existing ones provided in the output path of power from the solar cell. be able to.

  In the inspection apparatus of the solar power generation system, the IV characteristic generation unit can perform an inspection operation in which the change value is within the range of the inspectable value and the change value is set as a relatively small time zone. In the time zone, the measurement IV characteristic may be obtained.

  According to the above configuration, the IV characteristic generation unit obtains the measured IV characteristic when the change value is within the range of the testable value and the change value is in the test operation possible time zone which is a relatively small time zone. Ask.

  Therefore, for example, in a time zone in which the amount of power generation or power generation current value of the solar cell is large, the weather suddenly deteriorates, and the power generation amount or power generation current value of the solar cell is lowered, whereby the inspection operation of the inspection device is started. As a result of the rapid recovery of the weather and an increase in the amount of power or current generated by the solar cell, it is possible to prevent a situation that hinders the operation of the inspection apparatus. Thereby, the reliability of an inspection apparatus can be improved.

  In the inspection apparatus of the solar power generation system, the IV characteristic generation unit includes a sunshine amount detection unit that detects a sunshine amount of the position of the solar cell, and the change value is within the range of the inspectable value. And when the said sunshine amount is below a predetermined amount, it is good also as a structure which calculates | requires the said measurement IV characteristic.

  According to said structure, an IV characteristic production | generation means calculates | requires measurement IV characteristic, when a change value is in the range of a testable value, and the amount of sunlight of the position of a solar cell is below a predetermined amount.

  Therefore, in a time zone in which the amount of power generated by the solar cell or the amount of generated current is large (a state in which the amount of sunshine is large), for example, a part of the solar cell is covered with some covering, and therefore the amount of power generated by the solar cell or By reducing the generated current value, it is possible to prevent a situation in which an inspection operation of the inspection device is performed and an inappropriate inspection result is obtained.

  In addition, since the covering is removed during the inspection operation of the inspection device and the power generation amount or power generation current value of the solar cell is increased, it is possible to prevent a situation that hinders the operation of the inspection device. Thereby, the reliability of an inspection apparatus can be improved.

  The inspection method for a photovoltaic power generation system of the present invention includes an abnormality presence / absence determination step for determining the presence / absence of an abnormality of a solar cell by comparing a measured IV characteristic, which is an IV characteristic measured for the solar cell, with a reference IV characteristic. In the photovoltaic power generation system inspection method, the power generation amount of the solar cell, or a change value that is a value that changes in accordance with the power generation amount is within a range of inspectable values that is less than the maximum value of the change value of the solar cell. An inspection propriety determining step for determining whether or not there is an IV characteristic generating step for obtaining the measured IV characteristic from the output current and output voltage of the solar cell when the change value is within the range of the inspectable value. It is characterized by having.

  According to the above configuration, it is possible to perform the inspection with a small configuration by reducing the power handling value required for the configuration for obtaining the measurement IV characteristics.

  According to the configuration of the present invention, the required power withstanding value can be reduced and the configuration can be reduced.

It is a schematic circuit diagram which shows the structure of the solar energy power generation system of embodiment of this invention. It is a flowchart which shows operation | movement of the test | inspection apparatus shown in FIG. It is a graph which shows the change of the open circuit voltage and electric power generation amount in the solar cell string of the day when the test | inspection of the solar power generation system was performed by the test | inspection apparatus shown in FIG. It is a graph which shows IV curve in case the solar cell string shown in FIG. 1 is normal. It is a graph which shows IV curve in case the photovoltaic cell which failed in the photovoltaic cell string shown in FIG. 1 is contained. It is a flowchart which shows operation | movement of the test | inspection apparatus in the solar energy power generation system of other embodiment of this invention. It is a schematic circuit diagram which shows the structure of the photovoltaic power generation system of further another embodiment of this invention. It is a flowchart which shows operation | movement of the test | inspection apparatus in the solar energy power generation system shown in FIG. FIG. 9A is a circuit diagram showing a solar cell string configured by connecting a plurality of solar cell modules in series. FIG. 9B is a circuit diagram showing a state in which the solar battery cell is in a non-conductive state due to a failure in the solar battery module of the solar battery string shown in FIG. Graph showing an IV curve (solid line) when the solar cell string is normal and a IV curve (broken line) when the solar cell string includes a failed solar cell, which is generated by a conventional inspection apparatus. It is.

[Embodiment 1]
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic circuit diagram showing a configuration of a photovoltaic power generation system 1 according to an embodiment of the present invention.

  As shown in FIG. 1, the photovoltaic power generation system 1 includes a solar cell string 11, an inspection device 12, and a power conditioner 13. In the solar power generation system 1, the power generated by the solar cell string 11 is supplied to the power transmission network 14 via the inspection device 12 and the power conditioner 13.

  The solar cell string 11 includes a plurality of solar cell modules 21 connected in series, and a bypass diode 22 is connected in parallel to each solar cell module 21. The solar cell module 21 includes a plurality of solar cells connected in series, and is formed in a panel shape. The electric power generated by the solar cell string 11 is supplied to the power conditioner 13 through an energization path (power line) 15a and an energization path (power line) 15b which are power lines.

  The inspection device 12 includes a voltage sensor (voltage detection means) 31, a current sensor (current detection means) 32, a control unit (abnormality presence / absence determination unit, inspection availability determination unit, generation unit, semiconductor switch control unit, IV characteristic generation unit) 33. , Drive voltage output unit 34, SSR (Solid State Relay: solid state relay, semiconductor switch, IV characteristic generation means) 35, smoothing circuit 36, open / close switches 37a and 37b, fuse 38, and current path (short-circuit current path, IV characteristic generation) Means) 39.

  The voltage sensor 31 is connected in parallel with the solar cell string 11 and detects the output voltage of the solar cell string 11. The voltage sensor 31 has a resistance element of, for example, 1 MΩ or more provided in a circuit between the energization paths 15a and 15b. The current sensor 32 is provided in the energization path 15a, for example, and detects the current flowing through the energization path 15a, that is, the output current of the solar cell string 11. The current sensor 32 uses, for example, a low-resistance shunt resistor provided in the energization path 15a. Alternatively, a non-contact current sensor may be used.

  The open / close switch 37a is provided in the energizing path 15a and opens / closes the energizing path 15a. The open / close switch 37b is provided in the energizing path 15b and opens and closes the energizing path 15b. The open / close switches 37a and 37b are, for example, b-contact relays. The b-contact relay closes when not energized and opens when energized.

  The energization path 39 connects between the current sensor 32 and the open / close switch 37a in the energization path 15a and between the solar cell string 11 and the open / close switch 37b in the energization path 15b.

  The control unit 33 is composed of, for example, a microcomputer having a CPU, and the output voltage of the solar cell string 11 detected by the voltage sensor 31 and the output current of the solar cell string 11 detected by the current sensor 32, that is, a solar cell. The power generation amount (change value) of the string 11 is monitored, and the operation of the drive voltage output unit 34 and the open / close operation of the open / close switches 37a and 37b are controlled.

  Specifically, the control unit 33 is based on the output voltage of the solar cell string 11 and the output current of the solar cell string 11 at an appropriate timing when the power generation amount of the solar cell string 11 is small (for example, in the morning or evening time zone). Then, the drive voltage output unit 34 and the open / close switches 37a and 37b are controlled so that the inspection of the solar cell string 11 by the inspection device 12 is performed. In this case, the control unit 33 opens the open / close switches 37a and 37b, interrupts the energization paths 15a and 15b, and operates the drive voltage output unit 34.

  Further, the control unit 33 sets the output voltage of the solar cell string 11 detected by the voltage sensor 31 and the output current of the solar cell string 11 detected by the current sensor 32 during the inspection operation by the inspection device 12. Based on this, an IV curve of the solar cell string 11 is generated. Furthermore, the control unit 33 determines whether the solar cell string 11 is normal or abnormal based on the generated IV curve (measurement IV curve (measurement IV characteristic)) (a solar cell that has failed in the solar cell string 11). Is included). In this case, the control unit 33 stores the IV curve in the case where the solar cell string 11 is normal as a reference IV curve (reference IV characteristic) in an internal memory, and makes the above determination based on the generated IV curve. This is done by comparing with the IV curve.

  Note that the comparison of IV curves does not need to be compared for the entire IV curve, and may be performed by a method of comparing the slopes of curves in the vicinity of the open circuit voltage as described in Patent Document 2. Further, when the reference IV curve is stored in the memory, it is not necessary to store the entire reference IV curve, and only the slope of the curve near the open circuit voltage may be stored.

  On the other hand, the control unit 33 is configured so that the power generated by the solar cell string 11 is supplied to the power conditioner 13 when the inspection operation of the inspection device 12 is not performed, that is, during the normal operation of the solar power generation system 1. The open / close switches 37a and 37b are closed.

  The drive voltage output unit 34 is controlled by the control unit 33 to generate a drive signal (PWM signal) for driving the SSR 35. The SSR 35 is provided in the energization path 39 and opens and closes the energization path 39 in response to a drive signal from the drive voltage output unit 34. The smoothing circuit 36 includes a resistor R and a capacitor C, and is provided in the energizing path 39. The fuse 38 interrupts the circuit against an overcurrent, and is provided in the energization path 39. In the present embodiment, the smoothing circuit 36 is composed of the resistor R and the capacitor C, but may be other than this. Similarly, the overcurrent prevention element uses the fuse 38, but is not limited thereto.

  In the above configuration, the operation of the inspection apparatus 12 will be described below. Here, a case where the inspection device 12 inspects the solar cell string 11 in the early morning when the power generation amount of the solar cell string 11 is small will be described.

  FIG. 2 is a flowchart showing the operation of the inspection apparatus 12. FIG. 3 is a graph showing changes in the open circuit voltage and power generation amount in the solar cell string 11 on the day when the solar power generation system 1 is inspected by the inspection device 12. FIG. 4 is a graph showing an IV curve when the solar cell string 11 is normal. FIG. 5 is a graph showing an IV curve when the solar cell string 11 includes a failed solar cell.

  As shown in FIG. 2, the control unit 33 monitors the output voltage of the solar cell string 11 detected by the voltage sensor 31 and the output current of the solar cell string 11 detected by the current sensor 32 (S11). Then, it is determined whether or not the power generation amount of the solar cell string 11 is within a range in which the inspection device 12 can perform the inspection operation (S12). This determination may be made based on a current value (generated current value) instead of the generated power amount. That is, in the solar cell, the generated voltage hardly changes and the current value (generated current) changes due to the characteristics. Therefore, a change in the amount of power generation ≒ a change in the generated current, and whether or not the inspection device 12 can be inspected (within the range of inspectable values) is determined by whether the amount of power generation (change value) or current value ( This can be performed by either the generated current value or the (change value).

  The range in which the inspection operation of the inspection device 12 can be performed is based on the pressure resistance of the SSR 35 and the like, and a range in which an IV curve can be generated and the amount of power generation is small is set in advance. Between the sunrise and sunset of the place where the solar cell string 11 is installed, the open-circuit voltage and the power generation amount of the solar cell string 11 change as shown in FIG. 3, for example. In FIG. 3, a range A indicates an operating range of the power conditioner 13. Further, the region B is a region included in the inspection operation possible range of the inspection device 12 and exists in the early morning time zone when the power generation amount of the solar cell string 11 is small (inspectable value). In the region B, the open circuit voltage of the solar cell string 11 reaches the vicinity of a predetermined maximum voltage. On the other hand, the amount of sunlight is small because of early morning, and the output current of the solar cell string 11 is a small value.

  As a result of the determination in S12, if the power generation amount of the solar cell string 11 is within a range where the inspection operation of the inspection device 12 is possible, the control unit 33 opens the open / close switches 37a and 37b and the energization path that is a power line Blocks 15a and 15b (S13).

  Next, the control unit 33 outputs a PWM signal from the drive voltage output unit 34 to drive the SSR 35 (S14). Thereby, when the SSR 35 is turned on, a short-circuit current flows through the solar cell string 11, the energization path 15 a, the energization path 39, the energization path 15 b, and the solar cell string 11.

  The short circuit current that flows when the SSR 35 is driven by the PWM signal is smoothed by the smoothing circuit 36. In addition, when the amount of power generated by the solar cell string 11 suddenly increases and a large current flows through the inspection device 12, the fuse 38 is activated and the energization path 39 is interrupted. Thereby, the inspection apparatus 12 is protected.

  Next, based on the open circuit voltage of the solar cell string 11 detected by the voltage sensor 31 and the short-circuit current of the solar cell string 11 detected by the current sensor 32, the control unit 33 sets the IV of the solar cell string 11. A curve is generated (S15). In this case, the control unit 33 controls the drive voltage output unit 34 that outputs the PWM signal so that the short-circuit current becomes a constant and small value.

  If the power generation amount of the solar cell string 11 is small with respect to the power generation amount that can generate the IV curve at the time when the energization paths 15a and 15b are cut off, even if waiting until a predetermined power generation amount is obtained. Good.

  When the solar cell string 11 is normal, the IV curve generated by the control unit 33 is shown by a solid line in FIG. 4, and when the solar cell string 11 includes a failed solar cell. Is indicated by a solid line in FIG. In FIGS. 4 and 5, what is indicated by a one-dot chain line is an IV curve obtained in a conventional inspection apparatus when the solar cell string 11 is normal. Moreover, what is shown with a dashed-two dotted line is the IV curve obtained in the conventional test | inspection apparatus in case the solar cell string 11 contains the failed photovoltaic cell.

  The IV curves shown in FIGS. 4 and 5 are generated from the point of zero current to at least a predetermined current value, and then generated to the point of zero voltage in a constant current state, but are not limited to this. That is, in comparing the generated IV curve with the reference IV curve to determine whether or not the solar cell string 11 has failed, the IV curves shown in FIGS. 4 and 5 are at least a predetermined current from the point of zero current. It may be in a state of rising to the value. Alternatively, the IV curve may be an IV characteristic obtained by detecting a plurality of points such as (I1, V1) and (I2, V2) instead.

  Next, the control part 33 determines whether the solar cell string 11 is normal (S16). If the result of this determination is that the solar cell string 11 is normal, the process is terminated, and if the solar cell string 11 is abnormal (when the solar cell string 11 includes a faulty solar cell) A management device (not shown) is notified of this (S17), and then the process ends. In addition, when the solar power generation system 1 is normal, you may notify the said management apparatus of that.

  The determination of the control unit 33 is performed by comparing the generated IV curve (measured IV curve) with a reference IV curve. In this case, the reference IV curve (IV curve when the solar cell string 11 is normal) and the IV curve when the solar cell string 11 is abnormal (IV when the solar cell string 11 includes a failed solar cell) The curve and the slope are different from each other in the slope and shape near the rising portion from the point where the short-circuit current is zero. Therefore, it is possible to determine whether or not the solar cell string 11 is normal by comparing at least one of the inclination or shape of the IV curves of the above part.

  After the inspection by the inspection device 12, the control unit 33 closes the open / close switches 37a and 37b to make the energization paths 15a and 15b conductive. In this case, the open / close switches 37a and 37b are relays that are resistant to inrush current, so that the closing operation can be performed without any problem. When the open / close switches 37a and 37b are closed, the power generated by the solar cell string 11 is supplied to the power conditioner 13 via the energization paths 15a and 15b.

  As described above, the inspection device 12 inspects the solar cell string 11 at a timing when the power generation amount of the solar cell string 11 is small. At this timing, an output current from the solar cell string 11 is output. It is smaller (see region B in FIG. 3). Therefore, the SSR 35, which is a small semiconductor switch with a small withstand current, can be used as a switch for controlling the short-circuit current flowing through the energization path 39. Thereby, the test | inspection apparatus 12 can be set as a small structure.

  The inspection device 12 is configured to inspect the solar cell string 11 when the power generation amount of the solar cell string 11 is small. Therefore, the situation where the power generation amount of the solar cell string 11 is reduced by the operation of the inspection device 12 can be suppressed.

  Note that the control unit 33 opens the open / close switches 37a and 37b to cut off the energization paths 15a and 15b at an appropriate time at night (after sunset), and based on the outputs of the voltage sensor 31 and the current sensor 32. The power generation amount of the solar cell string 11 may be monitored. In this case, the inspection of the solar cell string 11 by the inspection device 12 can be easily and quickly started after sunrise. In this case, whether or not it is nighttime may be determined by monitoring the amount of current detected by the current sensor 32 for an appropriate time (for example, several hours).

  Moreover, in this Embodiment, although the test | inspection of the solar cell string 11 by the test | inspection apparatus 12 is performed early in the morning (after sunrise), you may make it perform in the evening (before sunset). Alternatively, it may be performed in the early morning (after sunrise) and in the evening (before sunset), every day, or every several days.

  Moreover, although this Embodiment showed about the example where one solar cell string 11 is connected with respect to the power conditioner 13, it is not limited to this. That is, a configuration in which a plurality of solar cell strings 11 are connected to the power conditioner 13 may be employed. In this case, the inspection device 12 may be provided for each of the plurality of solar cell strings 11. Alternatively, only one inspection device 12 may be provided for the plurality of solar cell strings 11 and may be used by switching to the plurality of solar cell strings 11.

[Embodiment 2]
Another embodiment of the present invention will be described below with reference to the drawings. The photovoltaic power generation system 1 according to the embodiment of the present invention includes an inspection device 41 instead of the inspection device 12 (see FIG. 1). The previous inspection device 12 is configured to perform an inspection operation when the amount of power generated by the solar cell string 11 is small. On the other hand, the inspection device 41 is configured to perform an inspection operation when the power generation amount of the solar cell string 11 is small and within a predetermined time zone.

  FIG. 6 is a flowchart showing the operation of the inspection apparatus 41 of the present embodiment. In the present embodiment, in the flowchart of FIG. 6, the same step number is appended to the same operation as that shown in the flowchart of FIG. 2, and the description thereof is omitted.

  The control unit 33 shown in FIG. 1 includes a timer inside, and measures time. Moreover, the inspection operation possible time zone is set in the memory provided in the control unit 33. The inspection operation possible time zone is a time zone during which the inspection device 41 can perform the inspection operation, and a time zone in which the amount of sunlight is small and the power generation amount of the solar cell string 11 is small is set.

  In the above configuration, the operation of the inspection apparatus 41 will be described below. Here, a case where the inspection device 41 inspects the solar cell string 11 in the early morning when the power generation amount of the solar cell string 11 is small will be described.

  As shown in FIG. 6, the control unit 33 monitors the output voltage of the solar cell string 11 detected by the voltage sensor 31 and the output current of the solar cell string 11 detected by the current sensor 32 (S11). Then, it is determined whether or not the power generation amount of the solar cell string 11 is within a range in which the inspection device 12 can perform the inspection operation (S12).

  As a result of the determination in S12, if the power generation amount of the solar cell string 11 is within the range in which the inspection operation of the inspection device 12 is possible, the control unit 33 further determines whether or not the inspection operation is possible time zone ( S21).

  As a result of the determination in S12, if the power generation amount of the solar cell string 11 is not within the range in which the inspection operation of the inspection device 12 is possible, and if the result of determination in S21 is not the inspection operation possible time zone, the process proceeds to S11. Return.

  On the other hand, if the result of determination in S21 is that the inspection operation is possible, the control unit 33 opens the open / close switches 37a and 37b and shuts off the energization paths 15a and 15b that are power lines (S13).

  Hereinafter, the inspection device 41 performs the operations of S14 to S17 as described above, and determines whether or not the solar cell string 11 is normal.

  As described above, in the inspection device 41, the amount of power generated by the solar cell string 11 is small, and the time zone at that time is a time zone in which the inspection operation is possible with a small amount of sunlight and a small amount of power generated by the solar cell string 11. In addition, an inspection operation is performed.

  Therefore, for example, in the time zone when the power generation amount of the solar cell string 11 is large, the weather suddenly deteriorates and the power generation amount of the solar cell string 11 decreases, whereby the inspection operation of the inspection device 41 is started, and then suddenly When the weather recovers and the power generation amount of the solar cell string 11 increases, it is possible to prevent a situation in which the operation of the inspection device 41 is hindered. Thereby, the reliability of the inspection apparatus 41 can be improved.

  Other functions are the same as those of the above-described inspection apparatus 12.

[Embodiment 3]
Still another embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 7, the photovoltaic power generation system 1 according to the embodiment of the present invention includes an inspection device 51 instead of the inspection device 12. FIG. 7 is a schematic circuit diagram showing the configuration of the photovoltaic power generation system 1 of the present embodiment. The previous inspection device 12 is configured to perform an inspection operation when the amount of power generated by the solar cell string 11 is small. On the other hand, the inspection device 51 is configured to perform an inspection operation when the amount of power generation is small and the amount of sunlight is not more than a predetermined amount.

  As shown in FIG. 7, the inspection device 51 includes a sunshine meter (sunshine amount detection means) 52 that measures the amount of sunlight at the installation position of the solar cell string 11. The amount of sunshine detected by the sunshine meter 52 is input to the control unit 33. When the amount of power generated by the solar cell string 11 is small, the amount of power generated is within the range in which the inspection device 12 can perform the inspection operation, and the amount of sunlight detected by the sunshine meter 52 is equal to or less than the predetermined amount. In addition, the inspection apparatus 12 is controlled so that the inspection operation is performed.

  In the above configuration, the operation of the inspection apparatus 51 will be described below. FIG. 8 is a flowchart showing the operation of the inspection apparatus 51 of the present embodiment. In the present embodiment, in the flowchart of FIG. 8, the same operations as those shown in the flowchart of FIG. 2 are denoted by the same step numbers, and the description thereof is omitted.

  As shown in FIG. 8, the control unit 33 monitors the output voltage of the solar cell string 11 detected by the voltage sensor 31 and the output current of the solar cell string 11 detected by the current sensor 32 (S11). Then, it is determined whether or not the power generation amount of the solar cell string 11 is within a range in which the inspection device 12 can perform the inspection operation (S12).

  As a result of the determination in S12, if the power generation amount of the solar cell string 11 is within a range where the inspection operation of the inspection device 12 is possible, the control unit 33 further reduces the sunshine amount to a predetermined amount (inspectable sunshine amount). It is determined whether there is (S31).

  As a result of the determination in S12, when the power generation amount of the solar cell string 11 is not within the range in which the inspection operation of the inspection device 12 is possible, and as a result of the determination in S31, the amount of sunshine exceeds a predetermined amount, Return to S11.

  On the other hand, as a result of the determination in S31, if the amount of sunshine is equal to or less than the predetermined amount, the control unit 33 opens the open / close switches 37a and 37b and shuts off the energization paths 15a and 15b that are power lines (S13).

  Hereinafter, the inspection device 51 performs the operations of S14 to S17 as described above, and determines whether or not the solar cell string 11 is normal.

  As described above, the inspection device 51 performs an inspection operation when the amount of power generated by the solar cell string 11 is small and the amount of sunlight at that time is equal to or less than a predetermined amount.

  Therefore, the solar cell module 21 of the solar cell string 11 is covered with some covering in the time zone where the solar cell string 11 generates a large amount of power (a state where the amount of sunlight is large). By reducing the amount of power generation, it is possible to prevent the inspection device 41 from performing an inspection operation and obtaining an inappropriate inspection result.

  Further, the covering is removed during the inspection operation of the inspection device 51 and the power generation amount of the solar cell string 11 is increased, so that a situation that hinders the operation of the inspection device 51 can be prevented. Thereby, the reliability of the inspection apparatus 51 can be improved.

  Other functions are the same as those of the above-described inspection apparatus 12.

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

  INDUSTRIAL APPLICABILITY The present invention can be used, for example, as an apparatus for inspecting the presence or absence of abnormality of a power generation apparatus in which a plurality of photovoltaic modules having a plurality of photovoltaic cells are connected in series.

DESCRIPTION OF SYMBOLS 1 Solar power generation system 11 Solar cell string 12 Inspection apparatus 13 Power conditioner 14 Electric power transmission network 15a Current path (power line)
15b Current path (power line)
21 Solar cell module 22 Bypass diode 31 Voltage sensor (voltage detection means)
32 Current sensor (current detection means)
33 control unit (abnormality presence / absence determination unit, inspection availability determination unit, generation unit, semiconductor switch control unit, IV characteristic generation means)
34 Drive voltage output unit 35 Solid state relay (semiconductor switch, IV characteristic generating means)
36 Smoothing circuit 37a Open / close switch 37b Open / close switch 38 Fuse 39 Current path (short-circuit current path, IV characteristic generating means)
41 inspection device 51 inspection device 52 sunshine meter (sunshine amount detection means)

Claims (6)

In an inspection apparatus for a solar power generation system including an abnormality presence / absence determination unit that determines the presence / absence of an abnormality of a solar cell by comparing a measurement IV characteristic that is an IV characteristic measured for a solar cell with a reference IV characteristic,
Current detection means for detecting the output current of the solar cell;
Voltage detecting means for detecting the output voltage of the solar cell;
Whether the change value that is one of the power generation amount of the solar cell and the value that changes according to the power generation amount is within a range of inspectable values that is less than the maximum value of the change value of the solar cell. An inspection availability determination unit for determining;
IV characteristic generating means for obtaining the measured IV characteristic from the output current and the output voltage when the change value is within the range of the inspectable value ,
The IV characteristic generation means includes
A short-circuit current path for short-circuiting the positive electrode and the negative electrode of the solar cell;
A semiconductor switch provided in the short-circuit energization path and opening and closing the short-circuit energization path;
A semiconductor switch control unit that controls driving of the semiconductor switch so that the measured IV characteristic rises from a point of zero current and then transitions to a point of zero voltage in a substantially constant current state;
An inspection apparatus for a photovoltaic power generation system, comprising: a generation unit that obtains the measured IV characteristic from the output current and the output voltage when the semiconductor switch is driven by the control of the semiconductor switch control unit . The semiconductor switch is a solid state relay in which an input unit that inputs a drive signal from the semiconductor switch control unit and an open / close operation unit that opens and closes the short-circuit energization path are insulated.
The inspection apparatus for a photovoltaic power generation system according to claim 1 , wherein the drive signal is a PWM signal. The short-circuit current path is provided to short-circuit the output line of the solar cell,
The IV characteristic generation means includes an open / close switch that opens and closes the output line, which is provided on the output side of the output line relative to the connection position of the short-circuit energization path.
The said production | generation part calculates | requires the said measurement IV characteristic, after making an on-off switch open, The inspection apparatus of the solar power generation system of Claim 1 or 2 characterized by the above-mentioned. The IV characteristic generation means is configured to measure the IV characteristic when the change value is within a range of the inspectable value and the change value is an inspection operation possible time zone set as a relatively small time zone. The inspection apparatus for a photovoltaic power generation system according to any one of claims 1 to 3 , wherein: The IV characteristic generation unit includes a sunshine amount detection unit that detects a sunshine amount at the position of the solar cell, the change value is within the range of the inspectable value, and the sunshine amount is a predetermined amount or less. The inspection apparatus for a photovoltaic power generation system according to any one of claims 1 to 3 , wherein the measurement IV characteristic is obtained. In the inspection method of the photovoltaic power generation system comprising the abnormality presence / absence determination step of determining the presence / absence of abnormality of the solar cell by comparing the measured IV characteristic, which is the IV characteristic measured for the solar cell, with the reference IV characteristic,
Whether the change value that is one of the power generation amount of the solar cell and the value that changes according to the power generation amount is within a range of inspectable values that is less than the maximum value of the change value of the solar cell. An inspection propriety determination step for determining;
An IV characteristic generation step of obtaining the measured IV characteristic from an output current and an output voltage of the solar cell when the change value is within the range of the inspectable value ;
In the IV characteristic generation step,
A short-circuit energization path that short-circuits the positive and negative electrodes of the solar cell, and a semiconductor switch that opens and closes the short-circuit energization path in the short-circuit energization path,
Controlling the driving of the semiconductor switch so that the measured IV characteristic rises from a point of zero current and then transitions to a point of zero voltage in a substantially constant current state;
An inspection method for a photovoltaic power generation system, wherein the measured IV characteristic is obtained from the output current and the output voltage when the semiconductor switch is driven when controlling the semiconductor switch .

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