JP2012169531A - Solar cell string inspection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar cell string inspection apparatus which specifies defective solar cell strings without using temporal data.SOLUTION: A solar cell string inspection apparatus 6 has: characteristic measurement means 8 measuring I-V characteristics from output power of a solar cell string 2 to be inspected; signal processing means 9 calculating an index from the characteristics measured by the characteristic measurement means 8; and comparison monitoring means 10 comparing the calculated index with pre-setting threshold values H and L, and display recording means 11 displaying and recording the results of the comparison between the index and the threshold values H and L.

Description

  Embodiments described herein relate generally to a solar cell string inspection apparatus.

  In recent years, the introduction of photovoltaic power generation systems has been rapidly increasing in response to the trend of deoiling energy. Large-scale solar power generation systems, which are said to be mega-solar with power generation output exceeding 1 MW, are being built in various countries. In this mega solar, tens of thousands of solar cell modules are sometimes used, and failure detection technology and maintenance technology are required.

  By the way, the output characteristics of the photovoltaic power generation system vary greatly depending on environmental conditions such as solar radiation intensity. For this reason, even if the original output is not obtained due to failure or deterioration of the solar cell module constituting the solar cell panel, dirt on the surface of the solar cell module, etc., the output decrease is mistaken as being due to the influence of environmental conditions. there is a possibility.

JP-A-8-64653 Japanese Patent Laid-Open No. 2001-24204 JP 2004-287787 A

  As described above, if there is an abnormal output module such as a faulty module in a solar cell string (a group of a plurality of solar cell modules connected in series), the expected power generation amount cannot be obtained and the investment is recovered. In some cases, there are problems such as a prolonged period of time required for safety and safety problems such as heat generation of the solar cell module.

  Therefore, it is necessary to detect an abnormal output module at an early stage and perform maintenance such as replacement, and when replacing a solar cell module, it can be said that the first step is to identify in which string the abnormal output module exists.

  On the other hand, in conventional solar cell system inspection methods, the output characteristics vary greatly depending on environmental conditions such as solar radiation intensity, so solar cell string output abnormalities due to solar cell module failure or deterioration, solar cell module surface contamination, etc. I couldn't judge.

  In addition, when data is detected and monitored over time for each solar cell string, it is impossible to determine whether there is an abnormality unless data is detected over a long period of time, and the period required for investment recovery is shortened. It was difficult and could cause safety problems.

  This invention is made | formed in view of the said situation, and it aims at providing the solar cell string test | inspection apparatus which can pinpoint a faulty solar cell string irrespective of time-dependent data.

  A solar cell string inspection apparatus according to an aspect of an embodiment includes a characteristic measurement unit that measures an IV characteristic from output power of a solar cell string to be inspected, and a signal process that calculates an index from the characteristic measured by the characteristic measurement unit Means, comparison monitoring means for comparing the calculated index and a preset threshold value, and display recording means for displaying and recording a comparison result between the index and the threshold value.

It is a figure which shows one structural example of the test | inspection apparatus and test | inspection object of 1st Embodiment. It is a figure which shows an example of the IV characteristic and PV characteristic of a solar cell string. It is a figure which shows an example of the characteristic of a non-defective solar cell string with the same solar radiation intensity, and a solar cell string including a defective module It is a figure which shows an example of the parameter | index (maximum output / irradiation intensity) calculated based on the characteristic and solar radiation intensity which were measured with the characteristic measuring device. It is a figure which shows one structural example of the test | inspection apparatus of 2nd Embodiment, and a test object. It is a figure which shows an example of the parameter | index (FF) calculated based on the characteristic measured with the characteristic measuring device. It is a figure which shows an example of the parameter | index ((maximum output / irradiation intensity) x FF ^ n) calculated based on the characteristic measured with the characteristic measuring device, and the solar radiation intensity. It is a figure for demonstrating the example of 1 structure of a solar cell module inspection apparatus. It is a figure for demonstrating the other structural example of a solar cell module test | inspection apparatus. It is a figure which shows an example of the measurement signal output from the signal input device of a solar cell module inspection apparatus. It is a figure which shows an example of the reflected signal or transmitted signal detected with the waveform observation apparatus of a solar cell module inspection apparatus. It is a figure which shows the other example of the reflected signal detected by the waveform observation apparatus of a solar cell module inspection apparatus, or a permeation | transmission signal.

Hereinafter, embodiments will be described with reference to the drawings.
The solar cell string inspection apparatus according to the present embodiment is an index based on characteristics measured by the means for measuring solar radiation intensity, characteristic measurement means for measuring the IV characteristics of the solar cell string to be inspected, and characteristic measurement means. Signal processing means for calculating the calculated index, a comparison monitoring means for comparing the calculated index with a preset threshold value, and a means for displaying and recording the comparison result between the index and the threshold value. Immediately determine whether there is a defective module in the battery string.

  FIG. 1 shows a configuration example of the solar cell string inspection device 6 and the inspection target according to the first embodiment. The solar cell string inspection device 6 according to the present embodiment calculates an index from the measured characteristics, a solar radiation meter 7 that measures the solar radiation intensity, a characteristic measuring device 8 that measures the characteristics of the solar cell string 2, and the like. The signal processing unit 9 includes a comparison monitoring unit 10 that compares the calculated index with a threshold value to determine whether the product is a non-defective product, and a display recording unit 11 that displays and records the comparison result of the comparison monitoring unit 10.

  The solar cell string inspection device 6 is connected to a solar power generation device including the solar cell string 2 to be inspected. The solar power generation device includes a plurality of solar cell strings 2 and a connection box 3 to which the plurality of solar cell strings 2 are connected via a release means 12.

  The solar cell string 2 includes a plurality of solar cell modules 1 connected in series. The high potential side and the low potential side of the plurality of solar cell modules 1 are connected to the connection box 3 via the release means 12, respectively. The solar cell string 2 attached to the connection box 3 can be disconnected from the solar cell device in units of strings by releasing the connection by the release means 12.

  The connection box 3 outputs the electric power output from the plurality of solar cell strings 2 to an electric power system or a load (not shown). The connection box 3 includes a first power line W1 connected to one pole of the solar cell string 2 and a second power line W2 connected to the other pole of the solar cell string 2. Electric power is output from each of the first power line W1 and the second power line W2 to the power system or the load.

  The other pole of the solar cell string 2 and the second power line W2 are connected via a changeover switch 5 and a backflow prevention diode 4. The changeover switch 5 switches the electrical connection between the high potential side of the solar cell string 2 and the second power line W2. The backflow prevention diode 4 is attached in a direction in which power is output from the solar cell string 2, and prevents backflow of power from the power system or the load side to the solar cell string 2.

  A first power line W <b> 1 and a second power line W <b> 2 extending from the connection box 3 are connected to the characteristic measuring device 8 of the solar cell string inspection device 6. The characteristic measuring device 8 further receives the solar radiation intensity from the solar radiation meter 7. The characteristic measuring device 8 operates the changeover switch 5 to connect one of the plurality of solar cell strings 2 to the first power line W1 and the second power line W2 during daytime power generation, and from the connection box 3 to a desired one. The output power of the solar cell string 2 is received. The characteristic measuring device 8 can calculate the IV characteristic and the PV characteristic of the solar cell string 2 from the output power received from the connection box 3. The characteristic measuring instrument 8 measures the IV characteristic for all of the plurality of solar cell strings 2, and the characteristic measuring instrument 8 supplies the measured characteristic and the solar radiation intensity to the signal processing unit 9. Note that the output of the pyranometer 7 may be directly input to the signal processing unit 9.

  In FIG. 2, an example of the IV characteristic and PV characteristic of the solar cell string 2 is shown. The characteristic measuring instrument 8 can measure the maximum output Pmax, the maximum operating voltage Vpm, the maximum operating current Ipm, the open circuit voltage Voc, and the short circuit current Isc of the solar cell string 2 by measuring the IV characteristics.

  FIG. 3 shows an example of IV characteristics and PV characteristics of a solar cell string 2 made up of only a non-defective solar cell module 1 with the same solar radiation intensity and a solar cell string 2 including a defective solar cell module 1. Indicates. In FIG. 3, the characteristics of the solar cell string 2 made of only non-defective products are indicated by solid lines, and the characteristics of the solar cell string 2 including defective products are indicated by broken lines.

  Comparing the characteristics of the solar cell string 2 composed only of non-defective products with the characteristics of the solar cell string 2 including defective products, the maximum output Pmax of the solar cell string 2 including defective products is It is lower than the maximum output Pmax.

  However, when the characteristics of the solar cell string 2 are measured outdoors, the solar radiation intensity is usually changed, and it is difficult to inspect by simply comparing the maximum output Pmax of the solar cell string 2.

  Here, in the crystalline silicon solar cell, it is known that the short-circuit current Isc is directly proportional to the solar radiation intensity. Therefore, it can be inferred that the maximum operating current Ipm is also correlated with the solar radiation intensity. Therefore, in the solar cell string inspection apparatus according to this embodiment, in order to reduce the influence of the solar radiation intensity, the solar cell string 2 is a non-defective product using the value obtained by dividing the maximum output (Pmax = Ipm × Vpm) by the solar radiation intensity as an index. It is determined whether or not there is.

  The signal processing unit 9 calculates the index (maximum output / intensity of solar radiation) from the characteristics of the solar cell string 2 measured by the characteristic measuring device 8 and the solar radiation intensity.

  FIG. 4 shows an example of an index (maximum output / irradiation intensity) calculated based on the characteristics measured by the characteristic measuring instrument 8 and the solar radiation intensity for each of the solar cell strings A to D. In addition, in the following description, in order to distinguish each of the plurality of solar cell strings 2, the solar cell strings are described with different signs A to D, but can be applied to the inspection of the plurality of solar cell strings 2. Needless to say.

  In this example, a defective solar cell module is included in the solar cell string B, and the solar cell strings A, C, and D are made only of non-defective products. The signal processing unit 9 calculates an index (maximum output / irradiation intensity) for each of the solar cell strings A to D a plurality of times, and supplies the calculated value to the comparison monitoring unit 10. In the example shown in FIG. 4, the index is calculated three times for each of the solar cell strings A to D.

  The comparison monitoring unit 10 determines whether or not the solar cell strings A to D are non-defective products based on whether or not the plurality of indexes received from the signal processing unit 9 are included in a preset threshold range. Specifically, for each of the solar cell strings A to D, it is determined whether or not the three indexes are equal to or lower than the first threshold value H1 and equal to or higher than the second threshold value L1 (first threshold value H1> second threshold value L1). .

  In the example illustrated in FIG. 4, the comparison monitoring unit 10 determines that the solar cell string B includes the defective solar cell module 1 because all of the three indexes of the solar cell string B are equal to or less than the second threshold L1. To do. The comparison monitoring unit 10 indicates that the three indexes of the solar cell strings A, C, and D are all the first threshold value H1 or less and the second threshold value L1 or more, so that the solar cell strings A, C, and D are non-defective solar cells. It is determined that the battery module 1 only is included.

  For example, when only one of the three indices is larger than the first threshold H1 or smaller than the second threshold L1, the comparison monitoring unit 10 has a low reliability of the one index. It may be determined that such a solar cell string does not include the defective solar cell module 1.

  In addition, for example, when only one of the three indicators is equal to or less than the first threshold H1 and the second threshold L1, the comparison monitoring unit 10 determines that the reliability of the one indicator is low, and Such a solar cell string may be determined to include a defective solar cell module 1.

  The comparison monitoring unit 10 outputs the result of determining whether or not the solar cell strings A to D are non-defective items to the display recording unit 11. The display recording unit 11 records the received determination result in a memory (not shown), and performs processing so that the determination result can be displayed on a display unit such as a display. The memory and the display unit may be mounted in the solar cell string inspection device 6 or may be connected to the outside. The user confirms the judgment result recorded by the display recording unit 11 and the judgment result displayed on the display means to know whether or not the solar cell strings A to D include the defective solar cell module 1. Can do.

  As described above, according to the present embodiment, it is possible to provide an inspection apparatus that can identify an abnormal solar cell string 2 regardless of temporal data. That is, according to the solar cell string inspection apparatus according to the present embodiment, it is possible to easily identify a solar cell string including a solar cell module whose output is reduced due to failure, deterioration, surface contamination, or the like. Furthermore, it is possible to avoid making an erroneous determination with an unreliable index and to perform a highly reliable test by calculating whether or not the product is non-defective by calculating the index multiple times as described above. it can.

Next, a solar cell string inspection device according to a second embodiment will be described with reference to the drawings.
The solar cell string inspection device according to the present embodiment includes a characteristic measuring unit that measures the characteristics of a solar cell string to be inspected, and an F.F. F. A signal processing means for calculating (fill factor, curve factor), a comparison monitoring means for comparing a preset threshold value with an index, and a display recording means for displaying and recording a comparison result between the index and the threshold value. Whether or not there is a defective solar cell module in the solar cell string is immediately determined regardless of the target data.

  FIG. 5 shows a configuration example of the solar cell string inspection device and the inspection target according to the second embodiment. In addition, in the following description, about the structure similar to the solar cell string inspection apparatus which concerns on the above-mentioned 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The solar cell string inspection device 6 according to the present embodiment does not include a pyranometer. The characteristic measuring instrument 8 calculates the characteristics of the plurality of solar cell strings 2 based on the output power of the plurality of solar cell strings 2 received from the connection box 3 in the same manner as in the first embodiment. Is output to the signal processing unit 9.

  The signal processing unit 9 calculates an index based on the characteristic received from the characteristic measuring device 8. In the present embodiment, F.D. F. (Fill factor, fill factor) is used as an index. F. F. It is known that the closer the value is to 1, the smaller the internal loss is, and it can be evaluated that it is an excellent module.

F. F. (Fill factor, curve factor) can be calculated by the following equation (1).
F. F. = Pmax / (Isc × Voc) (1)
FIG. 6 shows an example of the index (FF) calculated based on the characteristics measured by the characteristic measuring device 8 for each of the solar cell strings A to D. In this example, a defective solar cell module is included in the solar cell string B, and the solar cell strings A, C, and D are made only of non-defective products. The signal processing unit 9 calculates the index (FF) for each of the solar cell strings A to D a plurality of times, and supplies it to the comparison monitoring unit 10. In the example shown in FIG. 6, the index is calculated three times for each of the solar cell strings A to D.

  The comparison monitoring unit 10 determines whether or not the solar cell strings A to D are non-defective products based on whether or not the plurality of indexes received from the signal processing unit 9 are included in a preset threshold range. Specifically, for each of the solar cell strings A to D, it is determined whether or not the three indexes are equal to or less than the third threshold value H2 and equal to or greater than the fourth threshold value L2 (third threshold value H2> fourth threshold value L2). .

  In the example illustrated in FIG. 6, the comparison monitoring unit 10 determines that the solar cell string B includes a defective product because all the three indexes of the solar cell string B are equal to or less than the fourth threshold value L2. The comparison monitoring unit 10 indicates that the three indexes of the solar cell strings A, C, and D are all the third threshold value H2 or less and the fourth threshold value L2 or more, so that the solar cell strings A, C, and D are non-defective solar cells. It is determined that the battery module 1 only is included.

  As in the first embodiment described above, the comparison monitoring unit 10 may, for example, have a case where only one of the three indices is larger than the third threshold H2 or smaller than the fourth threshold L2. Judging that the reliability of the one index is low, such a solar cell string may be determined not to include the defective solar cell module 1.

  Further, for example, when only one of the three indicators is equal to or less than the third threshold H2 and the fourth threshold L2, the comparison monitoring unit 10 determines that the reliability of the one indicator is low, and Such a solar cell string may be determined to include a defective solar cell module 1.

  As described above, according to the present embodiment, it is possible to obtain the same effect as that of the solar cell string inspection apparatus according to the first embodiment described above. F. Is used as an index, the detection sensitivity can be increased as the number of solar cell modules 1 constituting the solar cell string 2 is smaller. Furthermore, since the configuration is simpler than that of the solar cell string inspection apparatus according to the first embodiment, the inspection apparatus cost can be reduced.

Next, a solar cell string inspection device according to a third embodiment will be described with reference to the drawings.
In the solar cell string inspection apparatus according to the second embodiment, F.I. F. As an index, when the number of solar cell modules 1 constituting the solar cell string 2 increases, the F. F. Since the contribution ratio to the lowering, the detection sensitivity may be slightly lowered. Therefore, in this embodiment, a more effective solar cell string inspection device is provided when the number of solar cell modules 1 constituting the solar cell string 2 is relatively large.

  The solar cell string inspection device 6 according to the present embodiment is the same as the solar cell string inspection device 6 according to the first embodiment, except that the index calculated by the signal processing unit 9 is different. The characteristic measuring instrument 8 calculates the characteristics of the plurality of solar cell strings 2 based on the output power of the plurality of solar cell strings 2 received from the connection box 3 in the same manner as in the first embodiment. And the solar radiation intensity are output to the signal processing unit 9.

  The signal processing unit 9 sets the maximum output to a value obtained by dividing the maximum output by the solar radiation intensity. F. A value obtained by multiplying n by the power of n (n = 1, 2, 3,...) Is used as an index for determining the string pass / fail.

  FIG. 7 shows an example of an index ((maximum output / intensity of solar radiation) × (FF) ^ n) calculated based on the characteristics measured by the characteristic measuring device 8 for each of the solar cell strings A to D. Indicates.

  In this example, a defective solar cell module is included in the solar cell string B, and the solar cell strings A, C, and D are made only of non-defective products. The signal processing unit 9 calculates an index ((maximum output / intensity of solar radiation) × (F.F.) ^ N) for each of the solar cell strings A to D a plurality of times, and supplies it to the comparison monitoring unit 10. In the example shown in FIG. 7, the index is calculated three times for each of the solar cell strings A to D.

  The comparison monitoring unit 10 determines whether or not the solar cell strings A to D are non-defective products based on whether or not the plurality of indexes received from the signal processing unit 9 are included in a preset threshold range. Specifically, for each of the solar cell strings A to D, it is determined whether or not the three indexes are equal to or less than the fifth threshold value H3 and equal to or greater than the sixth threshold value L3 (fifth threshold value H3> sixth threshold value L3). .

  In the example illustrated in FIG. 7, the comparison monitoring unit 10 determines that the solar cell string B includes the defective solar cell module 1 because all the three indexes of the solar cell string B are equal to or less than the sixth threshold L3. To do. The comparison monitoring unit 10 indicates that the three indexes of the solar cell strings A, C, and D are all the fifth threshold value H3 or less and the sixth threshold value L3 or more, so that the solar cell strings A, C, and D are non-defective solar cells. It is determined that the battery module 1 only is included.

  Note that, similarly to the first embodiment described above, the comparison monitoring unit 10, for example, when only one of the three indicators is larger than the fifth threshold H3 or smaller than the sixth threshold L3, Judging that the reliability of the one index is low, such a solar cell string may be determined not to include the defective solar cell module 1.

  Further, for example, when only one of the three indicators is equal to or less than the fifth threshold H3 or the sixth threshold L3, the comparison monitoring unit 10 determines that the reliability of the one indicator is low, and Such a solar cell string may be determined to include a defective solar cell module 1.

  As described above, according to the present embodiment, the same effect as that of the solar cell string inspection apparatus according to the first embodiment described above can be obtained, and the value obtained by dividing the maximum output Pmax by the solar radiation intensity and the F.V. F. Therefore, the detection sensitivity can be improved as compared with the individual indices. In addition, the value obtained by dividing the maximum output by the solar radiation intensity is F.V. F. The detection sensitivity can be further improved by multiplying the value obtained by multiplying n by the power of n.

  In the first to third embodiments, the comparison monitoring unit 10 compares the index with the threshold values H1 to 3 and L1 to 3, and determines whether the solar cell string includes the defective solar cell module 1 or not. However, immediately after the installation of the solar cell device, the initial IV characteristics of the plurality of solar cell strings 2 are obtained, and then the IV identification is measured again after a certain period of time. You may further judge whether it is a quality item by comparing.

  At this time, the quality determination index of the solar cell string 2 is a value obtained by dividing the maximum output used in the first embodiment by the solar radiation intensity, and the F.F used in the second embodiment. F. , And the maximum output divided by the solar radiation intensity used in the third embodiment. F. Any value obtained by multiplying n to the power of n may be used. When the inspection is performed as described above, it is possible to detect not only the failure of the solar cell string 2 but also the aged deterioration (decrease in output) of the solar cell string 2.

  As described above, according to the inspection apparatus according to the first to third embodiments, the solar cell string 2 including the solar cell module 1 whose output is reduced due to failure, deterioration, surface contamination, or the like can be easily identified. It is possible to provide a solar cell string inspection device that can identify a defective solar cell string 2 regardless of temporal data.

  Subsequently, a solar cell module inspection device that detects a defective solar cell module 1 in the solar cell string 2 determined to contain a defective product by the inspection devices of the first to third embodiments will be described.

  FIG. 8 is a diagram showing an example of the configuration of the solar cell module inspection apparatus. The solar cell module inspection device includes a signal input device 20 connected to one pole of the solar cell string 2 and a waveform observation device 30 connected to the pole to which the signal input device 20 is connected. An inverter INV is connected to the other pole of the solar cell string 2.

  Prior to detection of a defective solar cell module 1, an inspection environment with an illuminance of 1000 Lx or less is prepared, and the circuit of the target solar cell string 2 is opened. When the illuminance is 1000 Lx or less, the measurement can be performed under the condition that the variation in the amount of solar radiation is suppressed. Further, when the circuit of the solar cell string 2 is opened, the open end is formed to stabilize the impedance of the circuit composed of a plurality of solar cell modules, so that measurement can be performed with high accuracy.

  The signal input device 20 outputs measurement signals having different duty ratios to one pole side of the solar cell string 2. The measurement signal output from the signal input device 20 is transmitted from one pole of the solar cell string 2 to the other pole, reflected by the inverter INV, and transmitted from the other pole of the solar cell string 2 to one pole. , Detected by the waveform observation device 30.

  FIG. 10 shows an example of the waveform of the measurement signal output from the signal input device 20. The measurement signal output from the signal input device 20 is set to a predetermined duty ratio Tw / T1 (<1) so that at least a portion where the waveform becomes flat is generated in one cycle T1.

  FIG. 11 shows an example of the waveform of the reflected signal detected by the waveform observation device 30. In this example, an example in which a defective product module is included in the solar cell string 2 is shown. Since the defective solar cell module 1 has different impedance from the non-defective solar cell module 1, a delayed signal waveform is detected in the reflected signal reflected through the solar cell string 2 including the defective product.

  FIG. 12 shows another example of the waveform of the reflected signal detected by the waveform observation device 30. This example also shows an example in which a defective product module is included in the solar cell string 2. In this case, by adjusting the frequency of the measurement signal, the signal waveform amplified by interference in the defective solar cell module 1 is detected with a delay. When the delayed signal is amplified in this way, detection of the delayed signal is facilitated, measurement errors are reduced, and inspection accuracy can be improved.

  When a reflected signal as shown in FIG. 11 and FIG. 12 is detected, the time difference Tdelay of the delayed signal is measured by the waveform observing device 30, and the ratio of the time difference Tdelay to one cycle T1 (Tdelay / T1) is calculated. The defective module can be identified based on the value Lx (Lx = (Tdelay / T1) × LS) obtained by multiplying the overall length LS of the solar cell string 2. The value Lx decreases as the position of the defective module is closer to the signal input device 20 and increases as it is farther from the signal input device 20.

  Moreover, when installing a solar cell apparatus, it is also possible to diagnose the failure of a solar cell module by comparing with the reflected signal detected when it inspected.

  According to such a solar cell module inspection device, the signal input device 20 and the waveform observation device 30 can be installed in the same room, and the duty ratio can be easily controlled. As a result, detection accuracy can be improved. Further, since the signal input from the signal input device 20 can be measured by the waveform observation device 30 as a reflected signal, a failure can be detected even if the circuit is open due to disconnection or the like.

  FIG. 9 shows another configuration example of the solar cell module inspection apparatus. In the case shown in FIG. 9, the signal input device 20 connected to one pole of the solar cell string 2 and the waveform observation device 30 connected to the other pole (inverter INV side) of the solar cell string 2 are provided. ing. An inverter INV is connected to the other pole of the solar cell string 2.

  In this way, by connecting the waveform observation device 30 to the inverter INV side, the transmitted signal output from the signal input device 20 and transmitted via the solar cell string 2 can be easily measured, and the sun can be stably output. The defective solar cell module 1 in the battery string 2 can be detected.

  Even when the transmission signal is detected by the waveform observation device 30, the method of detecting the defective solar cell module 1 is the same as that by the reflected signal.

  According to the solar cell module inspection apparatus shown in FIG. 9, since the signal input from the signal input device 20 can be measured by the waveform observation device 30 as a transmission signal, a resistance change or the like inside the solar cell module 1 is measured. It is possible to detect a failure in a deteriorated state.

  The solar cell module inspection apparatus is particularly effective when applied to a system in which a large amount of solar cell modules 1 such as mega solar are used. That is, when the number of solar cell modules is small, such as for residential use, the state can be monitored by installing a wattmeter in each solar cell module 1, but as the number of solar cell modules increases, it is practically used from the viewpoint of cost. Not right. Therefore, it can test | inspect efficiently by inspecting every solar cell string 2 containing the some solar cell module 1 like the said solar cell module inspection apparatus.

  Further, by inputting a signal with a changed duty ratio and observing a signal waveform including a waveform amplified by interference between a reflected signal and a transmitted signal, waveform analysis that has been difficult to separate up to now becomes easy.

  That is, according to the solar cell module inspection apparatus shown in FIG. 8 and FIG. 9, a signal having a changed duty ratio is input, and a delayed waveform of a reflected signal and a transmitted signal, or a signal waveform including the amplified waveform. By observing, the failure location in the solar cell string 1 can be detected, and the maintenance work for replacing the solar cell module 1 can be easily performed.

  In the solar cell module inspection apparatus, a rectangular wave may be employed as the test signal. In that case, it is possible to detect a fault location in the solar cell string by adjusting the duty ratio so that a period during which the waveform becomes flat during one cycle and observing the waveform of the reflected signal or transmitted signal. It becomes.

  It is also possible to diagnose a failure by measuring a reflected signal or a transmitted signal while changing the duty ratio of the measurement signal at the time of installation of the solar cell device and comparing it with a waveform detected at the time of evaluation. In this case, it is possible to detect a failure such as a decrease in output due to aged deterioration by comparison with the initial state without depending on the installation form of the individual solar cell devices.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  W1 ... 1st power line, W2 ... 2nd power line, Pmax ... Maximum output, Vpm ... Maximum operating voltage, Ipm ... Maximum operating current, Voc ... Open circuit voltage, Isc ... Short-circuit current, 2, AD ... Solar cell string, H1 , H2, H3, L1, L2, L3... Threshold, 1... Solar cell module, 3... Junction box, 4. DESCRIPTION OF SYMBOLS ... Signal processing part, 10 ... Comparison monitoring part, 11 ... Display recording part, 12 ... Release means, 20 ... Signal input device, 30 ... Waveform observation apparatus.

Claims (7)

Characteristic measuring means for measuring the IV characteristic from the output power of the solar cell string to be inspected;
Signal processing means for calculating an index from the characteristic measured by the characteristic measuring means;
Comparison monitoring means for comparing the calculated index with a preset threshold;
A solar cell string inspection device comprising display recording means for displaying and recording a comparison result between an index and a threshold.   The solar cell string inspection device according to claim 1, wherein the index is a value obtained by dividing the maximum output of the solar cell string by a product of a short-circuit current and an open-circuit voltage of the solar cell string. It is further equipped with a pyranometer that measures solar radiation intensity,
The solar cell string inspection apparatus according to claim 1, wherein the index is a value obtained by dividing the maximum output of the solar cell string by the solar radiation intensity measured by the solar radiation meter. It is further equipped with a pyranometer that measures solar radiation intensity,
The index is a value obtained by dividing the maximum output of the solar cell string by the solar radiation intensity measured by the pyranometer, and the maximum output of the solar cell string is the product of the short-circuit current and the open-circuit voltage of the solar cell string. The solar cell string inspection device according to claim 1, which is a value obtained by multiplying the divided value by one or more times.   5. The solar cell string inspection device according to claim 1, further comprising a plurality of change-over switches that switch connection between the characteristic measuring unit and each of the plurality of solar cell strings.   6. The solar cell string inspection apparatus according to claim 1, wherein the characteristic measuring unit measures the characteristic of the solar cell string twice or more, and the signal processing unit calculates two or more indices. .   The solar cell string according to any one of claims 1 to 6, wherein the comparison monitoring unit includes an initial characteristic of the solar cell string, and compares the characteristic measured by the characteristic measurement unit with the initial characteristic. Inspection device.

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