WO2013151102A9

WO2013151102A9 - Solar cell array testing system

Info

Publication number: WO2013151102A9
Application number: PCT/JP2013/060236
Authority: WO
Inventors: 小澤　淳
Original assignee: 株式会社システム・ジェイディー
Priority date: 2012-04-03
Filing date: 2013-04-03
Publication date: 2014-01-09
Also published as: JP5205530B1; JP2013214631A; WO2013151102A1

Abstract

Proposed is a solar cell array testing system firstly capable of testing a parallel wiring type by a TDR system, secondly capable of being simply and easily obtained while being excellent in cost, and thirdly capable of being also expected to have an anti-surge effect. The testing system (12) identifies the presence or absence of a failure and other troubles of a solar cell array in which a plurality of strings (1) equipped with one or more modules (3) are connected in parallel. The testing system (12) has a testing device (11) and a delay means (13). Based on an outgoing signal to each of the strings (1) and a reflected signal from each of the strings (1), the testing device (11) separately identifies the presence or absence of a trouble of each of the strings (1). The delay means (13) sets the respective strings (1) to have a time-sequential front and rear relationship with each other with respect to either one of or both of the outgoing signal and the reflected signal and thereby sequentially inputs the reflected signals from the respective strings (1) to the testing device (11).

Description

Solar cell array inspection system

The present invention relates to a solar cell array inspection system. That is, the present invention relates to an inspection system for inspecting a solar cell array for the presence of a failure or other defects.

《Technical background》
Photovoltaic power generation (PV) has entered an era of mass diffusion, and various types of solar cells have been developed and commercialized.
At present, the mainstream is solar cells using silicon (Si), but the development of lower-cost, longer-life non-silicon type solar cells is also progressing.
That is, single crystal silicon type and polycrystalline silicon type so-called crystal type modules have been mainstream. However, these days, amorphous silicon type so-called thin-film modules, compound-based and organic modules that do not use silicon (also called thin-film systems), which are expensive and use less silicon, is in demand. Non-silicon type modules are also increasing rapidly. And it is expected to become a future trend.

On the other hand, with regard to photovoltaic power generation, the number of installations has increased and entered the mass diffusion era, many failures and other malfunctions have been reported, and early detection is required.
That is, disconnection, cracks, solder defects, and the like have occurred in the strings and modules that are constituent elements of a solar cell array for photovoltaic power generation, and the amount of power generation often decreases. Possible causes include poor construction, deterioration over time, damage from typhoons, earthquakes, small animals, and so on.
In any case, early detection of malfunctions such as failures, that is, early diagnosis of degraded strings has become a major theme recently. If early detection and early diagnosis can be performed, it is possible to immediately take measures such as repair.

<Conventional technology>
As an inspection method for such a solar cell array, first, an inspection method for measuring a current and a voltage flowing in a string that is actually generating power and finding a defect such as a failure in a string unit, a so-called IV method can be mentioned. .
On the other hand, recently, an inspection method exclusively for solar cell arrays has been developed and used. In other words, during non-power generation, a so-called TDR method, in which an outgoing signal is transmitted to a string and a reflected signal from the string is received and a failure such as a failure is judged by comparing the waveforms of both signals, is also put into practical use. ing.
Compared with IV method, TDR type inspection device can further identify faults in module units from the string unit. In addition, numerical values of the degree of failure can be grasped by waveform comparison. There are advantages such as being able to inspect at night without having to go up, no need to climb the roof.
As described above, since the TDR type inspection apparatus can identify a defect, it is easy to replace only a defective module, and reliable array management can be performed, and the safety of the operator is improved.

Examples of such a TDR inspection apparatus include those disclosed in the following Patent Document 1 and Patent Document 2.
JP 2011-35000 A JP 2009-21341 A

By the way, the following problems have been pointed out with respect to such a TDR inspection apparatus.
<First problem>
First, serial wiring can be inspected, but parallel wiring cannot. That is, the TDR type inspection apparatus determines a defect such as a failure based on the comparison of the waveform of the outgoing signal and the reflected signal. Conventionally, the inspection can be performed only when all the solar cell arrays to be inspected are of the serial wiring type. That is, inspection is possible only when all the strings and modules constituting the solar cell array are connected in series.
On the other hand, when the solar cell array is a parallel wiring type, the inspection is impossible. When multiple strings or modules are wired in parallel, the reflected signals are input and received in an overlapping manner, so it is impossible to determine which string is reflected from which string or which module or module is defective. .

Now, solar cell arrays using the above-described crystalline modules are classified into the above-described series wiring type and parallel wiring type.
On the other hand, the above-mentioned parallel wiring type is the mainstream in the solar cell array using the compound type and organic type modules including the amorphous silicon type thin film type described above.
The reason for this is that, because of the electrical characteristics, the power generation tendency per module is high voltage and low current, so that all of them are of the parallel wiring type in order to increase the current value.
Conventional TDR inspection devices are limited to use only in series wiring type, and it has been pointed out that they cannot be used in parallel wiring type solar cell arrays.

<< Second problem >>
In spite of the above, when the conventional TDR inspection device is used for a parallel wiring type solar cell array, as shown in FIG. It was necessary to attach each string 1 or connect sequentially for inspection.
For these, the number of inspection devices 2 has increased, and the cost of the configuration has been increased accordingly, or the troublesome time required for inspection has been pointed out, and the man-hours have been increased accordingly.
In FIG. 3B, 3 is a module, 4 is a relay terminal box, 5 is a power conditioner, and 6 is a cable.

<< About the present invention >>
In view of such a situation, the solar cell array inspection system of the present invention has been made to solve the above-described problems of the prior art.
In the present invention, firstly, a parallel wiring type solar cell array can be inspected by the TDR method, and secondly, this can be realized easily and easily in terms of cost, and thirdly, a surge countermeasure effect The purpose is to propose a solar cell array inspection system that can be expected.

A first aspect of the present invention is a solar cell array inspection system that determines whether or not there is a failure or other malfunction in a solar cell array in which a plurality of strings including one or more modules are connected in parallel. And it has an inspection device and a delay means.
The inspection apparatus determines whether or not there is a defect individually for each string based on the emission signal to each string and the reflection signal from each string.
The delay means sets a priori relationship in time series for each of the strings with respect to one or both of the outgoing signal and the reflected signal, so that the reflected signal from each of the strings is sent to the inspection device. It functions to make it input sequentially.

A second aspect of the present invention is an inspection system according to the first aspect, and the inspection apparatus includes an application unit, an actual measurement unit, and a determination unit.
The application unit transmits an emission signal to each string via a cable. The actual measurement unit receives a reflected signal reflected and reflected from the abnormal point of each string via the cable. The discriminating unit discriminates the presence / absence of a defect individually for each of the strings based on a waveform comparison between the outgoing signal and the reflected signal.
The delay means includes a delay circuit, and is interposed in the cable. The reflected signal from each string is input to and received by the actual measurement unit of the inspection apparatus in series for each string. Features.
According to a third aspect of the present invention, there is provided the inspection system according to the second aspect, wherein the delay unit is connected to at least the second and subsequent strings of the cable after being branched in parallel toward the strings. Is intervened.
Then, the delay constant of the delay means is such that the arrival time of one or both of the outgoing signal and the reflected signal between each string and the actual measurement unit of the inspection apparatus is made different for each string, so that each string has a different arrival time. It is characterized by comprising values that sequentially set a priori relationship in time series.
According to a fourth aspect of the present invention, there is provided an inspection system for discriminating whether or not there is a failure or a malfunction with respect to a solar cell array in which a plurality of strings each having one or more modules are connected in parallel. An application unit that applies a signal; an actual measurement unit that actually measures a reflected signal from the string; and a determination unit that determines whether or not the solar cell array has failed or malfunctioned based on the reflected signal. The inspection system further includes delay means for delaying the arrival of the reflected signal and setting a prior relationship of the reflected signals.
A fifth aspect of the present invention is the inspection system according to the fourth aspect, wherein the application unit is connected to a point farther from the string than a branch point of the plurality of strings connected in parallel. The delay means is connected between the branch point and at least one of the plurality of strings, and delays either one or both of the emission signal and the reflection signal to the measurement unit. The arrival of the reflected signal is delayed.
According to a sixth aspect of the present invention, there is provided the inspection system according to the fifth aspect, wherein the delay unit is configured to transmit a reflected signal from the point closest to the actual measurement unit of the string to which the delay unit is connected to the actual measurement unit. The reflected signal is delayed so that the shortest arrival time after delay is later than the non-delay longest arrival time of the reflected signal from the point farthest from the actual measurement unit of the string to which the delay means is not connected to the actual measurement unit.
According to a seventh aspect of the present invention, there is provided the inspection system according to the sixth aspect, comprising a plurality of the delay means connected to the different strings, and the delay time of each delay means is the shortest arrival after the delay. It is greater than the time difference between the time and the non-delayed longest arrival time.

<About the action>
Since the present invention comprises such means, the following is achieved.
(1) In this solar cell array, a plurality of strings are connected in parallel.
(2) In the inspection apparatus of this inspection system, the outgoing signal that has been branched and propagated between each string is transmitted and the reflected signal from the abnormal point is received. The presence or absence of other defects is determined.
(3) Now, in this inspection system, the delay means is interposed in the cable of the string, and the prior relationship is set in time series with respect to the reflected signal from each string.
(4) Therefore, the reflected signals are sequentially received by the inspection device serially for each string, and the situation where the reflected signals are received in an overlapping manner is avoided.
(5) Therefore, the inspection apparatus can individually determine which string has an abnormal point and a failure or other malfunction occurs.
(6) This is easily realized with a simple inspection system by providing a delay circuit in the cable of the string and using only one inspection apparatus.
(7) It should be noted that this inspection system is also effective as a surge countermeasure because the components of the delay circuit are burned out when the current or voltage suddenly rises due to lightning or the like.
(8) Now, the solar cell array inspection system of the present invention exhibits the following effects.

<< First effect >>
First, a parallel wiring type solar cell array can be inspected by the TDR method. In the inspection system for a solar cell array of the present invention, a delay unit is interposed in a string cable connected in parallel.
Therefore, for the reflected signal from each string, the prior relationship is set in time series, and sequentially received by the inspection device in series. Unlike the above-described conventional TDR inspection apparatus of this type, the reflected signals from the strings are not received in an overlapping manner, and it is possible to accurately determine which module of which string has a defect. .
Therefore, according to the inspection system of the present invention, parallel wiring type crystal modules, strings, solar cell arrays, parallel wiring type amorphous silicon thin film systems, compound systems, organic modules, strings, solar The battery array can be inspected.
The presence or absence of these failures and other problems can be reliably determined by the TDR method,
It is possible to take necessary measures such as repair and replacement for strings and modules in which defects are found.

<< Second effect >>
Secondly, this is simple and easy and is realized with good cost. Thus, the solar cell array inspection system of the present invention can inspect a parallel wiring type solar cell array by the TDR method. This is realized by providing delay means including a known delay circuit in the cable of the string and using one inspection device.
Unlike the above-described conventional TDR inspection apparatus of this type, the present invention is realized without the necessity of attaching or sequentially connecting a plurality of strings. Therefore, the configuration is simplified correspondingly, and the configuration cost is excellent. Further, the inspection does not require labor and time, and the man-hour cost is excellent.

《Third effect》
Thirdly, a surge countermeasure effect can be expected. In the solar cell array inspection system of the present invention, each string cable is provided with a delay means using a delay circuit.
Therefore, for example, when the current or voltage suddenly rises due to lightning or the like, the components forming the delay circuit are burned out at that moment. As a result, surge current and surge voltage can be reduced and cut off, and damage to the entire solar cell array, such as failure and destruction, can be minimized.
As described above, the effects exerted by the present invention are remarkably large, such as all the problems existing in this type of conventional example are solved.

The inspection system for a solar cell array according to the present invention is provided for explanation of an embodiment for carrying out the invention. (1) FIG. 2 is an explanatory diagram of a circuit configuration, and (2) is an arrival time of an outgoing signal in the circuit. FIG. 3 is a time chart of an example of a return time of a reflected signal in the circuit. FIG. 3 is a block diagram illustrating a configuration of a delay circuit of a delay unit for explaining the embodiment for carrying out the invention, in which FIG. 1A shows an example thereof, and FIG. 2B shows another example. For explanation of the mode for carrying out the invention, FIG. 1A is a block diagram of a circuit. (2) FIG. 2 is a block diagram of this type of conventional circuit. It is a perspective explanatory view of an example of a solar power generation system.

Hereinafter, embodiments for carrying out the present invention will be described in detail.
《About photovoltaic power generation》
First, the outline | summary of the photovoltaic power generation (PV) used as the premise of this invention is demonstrated with reference to FIG.
The direct-current side solar cell array 7 constituting the main part of the photovoltaic power generation is installed outdoors such as a roof. A plurality (four in the illustrated example) of the strings 1 are connected in parallel, and each string 1 normally includes a plurality (six in the illustrated example) of modules 3 connected in series. .
Independently of this, one string 1 can be composed of one module 3. Also, the chip constituting the module 3 can be configured with a single pn junction, a plurality of pn junctions connected in series, a plurality of pn junctions connected in parallel, and so on. is there.
The electric power generated and output by the solar cell array 7, that is, the direct current generated based on the photoelectric effect of the pn junction of the module 3 is transmitted from each string 1 to the cable 6 (see also FIG. 1 (1)). ), Reaching the power conditioner 5 via the relay terminal box 4.
The alternating current converted from the direct current by the power conditioner 5 is consumed by the load 9 after passing through the distribution board 8. Surplus power is purchased through the power meter 10 to the commercial power system of the power company. The module 3 may be referred to as a solar cell, and the string 1 may be referred to as a solar panel or a solar module.
The overview of solar power generation is as above.

<< About the outline of the inspection apparatus 11 >>
Hereinafter, the inspection system 12 of the present invention will be described. First, the inspection apparatus 11 of the inspection system 12 will be described with reference to FIG. 3 (1), FIG. 1 (1), and the like.
As described above, the inspection system 12 determines whether or not there is a failure or other malfunction in the solar cell array 7 in which the plurality of strings 1 including one or more modules 3 are connected in parallel. And it has the inspection apparatus 11 and the delay means 13.
The inspection apparatus 11 individually determines the presence or absence of a defect for each string 1 based on the emission signal to each string 1 and the reflection signal from each string 1. The inspection apparatus 11 includes an application unit 14, an actual measurement unit 15, and a determination unit 16.
The application unit 14 outputs and transmits an emission signal to each string 1 via the cable 6. The actual measurement unit 15 inputs and receives a reflected signal reflected and reflected from the abnormal point C of each string 1 via the cable 6. The discriminating unit 16 discriminates the presence or absence of defects individually for each string 1 based on the waveform comparison between the outgoing signal and the reflected signal.
The outline of the inspection apparatus 11 is as described above.

<< Details of Inspection Device 11 >>
Such an inspection apparatus 11 will be described in more detail with reference to FIG. 1 (1), FIG. 3 (1), and the like.
First, one inspection device 11 of this inspection system 12 is used, and is connected to the cable 6 via a switch 17 that is normally open (disconnected) and switched to closed (continuous) when used.
Of course, a portable type inspection device 11 is also possible instead of such a fixed type, and in the case of the portable type, it is connected to the cable 6 in use. 3 is a switch provided between the relay terminal box 4 and the power conditioner 5 and is normally closed (continuous), but is switched to open (disconnected) at the time of inspection.
In addition, the inspection device 11 of the illustrated example is provided between the relay terminal box 4 and the power conditioner 5 independently of each other. However, the relay terminal box 4 and the power conditioner are not limited to the illustrated example. 5 may be attached. However, it is connected to the cable 6 before being branched in parallel toward each string 1.

The application unit 14 of the inspection apparatus 11 is typically composed of a pulse generator, generates a pulse wave, and outputs, transmits, and applies an emission signal as an input signal to each string 1 to be inspected.
The actual measurement unit 15 of the inspection apparatus 11 is made of, for example, an oscilloscope, and inputs, receives, and measures a reflected signal that is reflected and reflected from the abnormal point C of the string 1 corresponding to the outgoing signal. Regarding these specific configurations, various known examples are known in addition to the above-described conventional technology.
The abnormal point C means a part that causes a failure or other trouble with respect to the string 1 and the module 3. It does not mean a connection point or a reflection point that other systems have.
As the determination unit 16 of the inspection apparatus 11, a microcomputer of the control unit 19 is typically used, and its CPU performs a predetermined process based on a stored program.

The determination unit 16 of the inspection apparatus 11 will be described in further detail. The discriminating unit 16 compares the output signal from the applying unit 14 to the inspection target string 1 and the reflected signal from the abnormal point C of the string 1 via the actual measurement unit 15 as inspection data.
Typically, total data comparison of both pulse waves is performed. Then, based on the waveform difference according to the abnormal point C of the string 1, that is, the position of the defective part, the waveform difference according to the type of inconvenient content, etc., the defective position is specified for each module 3, and the degree of the defect is also a numerical value. Be grasped.
By the way, such a data comparison includes a case where the reflected signal at the normal time is compared with the reflected signal at the time of inspection.
That is, in this specification, the description of comparing the output signal to the string 1 and the reflected signal from the string 1 includes the reflected signal from the string 1 in the past normal state (the output signal to the string 1). And a case where the reflected signal from the string 1 at the time of actual inspection is compared is also included as a part thereof.
As a result, the determination unit 16 diagnoses and determines the presence or absence of a failure such as a disconnection or other defects with respect to the string 1 to be inspected, and obtains an inspection result. The specific inspection procedure for each string 1 will be described later.
Details of the inspection apparatus 11 are as described above.

<< About the delay means 13 >>
Next, the delay means 13 of the inspection system 12 of the present invention will be described. First, the outline will be described with reference to FIG. 1 (1), FIG. 3 (1), and the like.
The delay means 13 sets a chronological relationship between each of the strings 1 connected in parallel for each of the strings 1 connected in parallel with respect to one or both of the outgoing signal and the reflected signal. It functions to sequentially input the reflected signal to the inspection apparatus 11. The reflected signal from each string 1 is input to and received by the actual measurement unit 15 of the inspection apparatus 11 sequentially in series for each generated string 1.
As such a delay means 13, the following three types can be considered. First (1), the delay means 13 is a first type in which only the outgoing signal to each string 1 is given a delay to set a prior relationship with others. By such first type delay means 13, the reflected signals from each string 1 are sequentially input to the inspection apparatus 11 individually.
Next, (2), a second type in which only the reflected signal from each string 1 is given a delay to set a prior relationship with others. By such second type delay means 13, the reflected signals from the respective strings 1 are sequentially input to the inspection apparatus 11 in the same manner as in the first type.
Further, (3) a third type in which both the outgoing signal to each string 1 and the reflected signal from each string 1 are given a delay and set a prior relationship with others. Also by the third type delay means 13, the reflected signals from the respective strings 1 are sequentially input to the inspection apparatus 11 in the same manner as in the first type and the second type.

Then, the first type, second type, or third type of delay means 13 is between the at least second and subsequent strings 1 with respect to the cable 6 after being branched in parallel toward each string 1. Intervened.
That is, the cable 6 is connected to each string 1 at one end and connected to the power conditioner 5 at the other end, but is branched in parallel on the way to correspond to the parallel relationship of the strings 1. Such parallel branch portions of the cable 6 are usually arranged in the relay terminal box 4 (see FIG. 3 (1)) or in the power conditioner 5.
The delay means 13 is interposed between each of the strings 1 with respect to the cable 6 after being branched in parallel in this way. Typically, it is interposed in the cable 6 immediately after the parallel branch.
By the way, the delay means 13 is interposed in all the cables 6 after being branched in parallel in the illustrated example. In the example of FIG. 1A, the delay means 13 is interposed in each of the two cables 6 after being branched in parallel. In the example of FIG. 3 (1), the delay means 13 is interposed in each of the four cables 6 after being branched in parallel.
On the other hand, a configuration in which the delay means 13 is not provided for one of the cables 6 after being branched in parallel is also possible. In other words, the purpose of the delay means 13 is to set the chronological relationship between each signal in time series. From this point of view, it is possible not to provide the delay means 13 for the cable 6 of the string 1 that is first in time series, that is, set to the shortest time without being delayed.
The delay means 13 is as described above.

<< Overview of Delay Constant D >>
Next, the delay constant D set for each of the delay means 13 of the inspection system 12 will be described with reference to FIG.
In view of the above, on the basis of the delay constant D of each delay means 13, the arrival time for one or both of the outgoing signal and the reflected signal between each string 1 and the actual measurement unit 15 of the inspection apparatus 11 is determined for each string 1. It will be different in length.
Accordingly, the delay constant D is a value that sequentially sets the prior relationship in time series between the signals. That is, a different predetermined value is set for each.
The outline of the delay constant D is as described above.

<< Specific Example of Delay Constant D >>
Next, a specific example of the delay constant D of the delay means 13 of the inspection system 12 will be described in detail with reference to FIG.
First, in the example shown in (1) figure 1, two string ₁ 1, _{1 2} are connected in parallel, one line of cable 6, the two cables _61, the _{6 2} While branching to the line, delay means 13 ₁ and 13 ₂ are interposed in each line. Both

strings

1 ₁ and 1 ₂ each include at least one module 3, in the illustrated example, a plurality of

modules

3 ₁ and 3 ₂ connected in series.
The start point of the string 1 ₁ is 20 ₁ , the end point of the string 1 ₁ is 21 ₁ , the start point of the string 1 ₂ is 20 ₂ , and the end point of the string 1 ₂ is 21 ₂ . Further, the delay constant of the delay means ₁₃ 1, 13 _2, respectively, and _D 1, _{D 2.} Note assumption, the

delay unit

₁₃ 1, 13 _2, and the third type described above. In other words, both of the outgoing signal and the reflected signal are of the third type in which a delay is given at the same time to set a prior relationship with others.

[Correction based on Rule 91 17.09.2013]
Next, in the illustrated example, the arrival time of the outgoing signal from the application unit 14 of the inspection apparatus 11 to each place is expressed as shown in FIG.
First, the delay means ₁₃ 1, 13 the arrival time of the emitted signals of up to _2, respectively T. 13 ₁ and T.W. 13 is represented by _2. And this arrival time T.I. 13 ₁ and T. 13 ₂ , that is, (A) in the figure, is mainly determined by the wiring length of each cable 6 from the application section 14 of the inspection apparatus 11 to the delay means 13 ₁ and 13 ₂ .
Note that the wiring from the application unit 14 to ~ delay means 13 _1, and the wiring from the application unit 14 to ~ delay means 13 _2, but may differ, in that case, delay constant _D 1, _{D 2} When setting, the amount is added or subtracted.

[Correction based on Rule 91 17.09.2013]
Next, in (2) of FIG. 1, the string _{1 1,} as follows. Arrival time T. of the outgoing signal from the application unit 14 of the inspection device 11 to the starting point 20 ₁ ~ String _{1 1} 20 _1, the T. a time to reach delay unit 13 ₁ To 13 _1, and those in the delay time _{T 1,} that view is determined by the delay constant _{D 1} of the delay means 13 ₁ (B), was added. The delay constant _{D 1} and the delay time _{T 1,} 0 even soluble (i.e., possible that the delay means 13 ₁ is not provided).
And for string _{1 1,} the exit signal of the arrival time to the start point 20 ₁ T. The arrival time T. of the outgoing signal from 20 ₁ to the end point 21 ₁ . Until 21 _1, as defective points C _1, that is if there is somewhere anomalies C ₁ in in FIG. (C), the reflected signal is generated in response reflected.
Then, in (2) of FIG. 1, the string _{1 2,} as follows. Arrival time T. of the outgoing signal from the application unit 14 of the inspection apparatus 11 to the beginning 20 ₂ ~ string _{1 2} 20 _2, the T. a time to reach delay unit 13 ₂ To 13 _2, and that the delay time _{T 2} which is determined by the delay constant _{D 2} of the delay means 13 _2, it was added.
In the figure, (D) shows the arrival time T. of the outgoing signal to the end point 21 ₁ of the previous string 1 ₁ . 21 _1, arrival time T. of the outgoing signal to the start point 20 ₂ of this string _{1 2} Time difference between the 20 _2, showing a time lag. The delay constants D ₁ and D ₂ of the

delay units

13 ₁ and 13 ₂ are set so that such a time lag (D) occurs. That is, T.M. 21 ₁ <T. D ₁ and D ₂ are set so as to be 20 ₂ .
And for string _{1 2,} outgoing signal time to reach the starting point 20 ₂ T. 20 of the emission signal from ₁ to ~ endpoint 21 ₂ arrival time T. Until 21 _2, when there is abnormal point C _2, that is, when there is somewhere anomalies C ₂ in in FIG. (E), in response reflected the reflected signal is generated.

[Correction based on Rule 91 17.09.2013]
Now, in the illustrated example, the return time of the reflected signal is represented as shown in FIG.
That is, the output signal transmitted and transmitted from the application unit 14 of the inspection apparatus 11 is reflected and reflected by the abnormal points C ₁ and C ₂ of the

strings

1 ₁ and 1 ₂ to be inspected, and is again measured by the measurement unit of the inspection apparatus 11. The return time until it is input to 15 and received is as follows.
First, when there is an abnormal point C ₁ somewhere in the string 1 ₁ , the return time is T.I. 20 ₁ × 2 to T.W. It is expressed as 21 ₁ × 2. That is, (A) × 2 + (B) × 2 to (A) × 2 + (B) × 2 + (C) × 2 are represented.
Further, if there is somewhere anomalies C ₂ of string 1 _2, the return time, T. 20 ₂ × 2 to T.W. 21 ₂ × 2. That is, from (A) × 2 + (B) × 2 + (C) × 2 + (D) × 2 to (A) × 2 + (B) × 2 + (C) × 2 + (D) × 2 + (E) × 2 .

The delay constants D ₁ and D ₂ of the delay means 13 ₁ and 13 ₂ are equal to T.D. 21 ₁ × 2 <T. It is set to be 20 ₂ × 2.
That is, the return time T. of the reflected signal when the abnormal point C ₁ exists at the end point 21 ₁ of the string 1 ₁ . 21 ₁ than × 2, resulting time of the reflected signal when there is abnormal point _{C 5} to the starting point 20 ₂ strings _{1 2} T. 20 ₂ × 2 is set to be longer and slower.
First, for strings 1 connected in parallel, in general, T.I. 21 _n × 2 <T. The delay constants D ₁ and D ₂ are sequentially set so as to be 20 _{n + 1} × 2. n is a positive integer.
For example, the delay means is the point where the shortest arrival time after the delay of the reflected signal from the point closest to the string measurement unit to which the delay unit is connected is the farthest from the string measurement unit to which the delay unit is not connected. The reflected signal is delayed so as to be later than the non-delayed longest arrival time of the reflected signal from to the actual measurement unit.
Second, there is no abnormal point C for the string 1 and a reflected signal may not be generated. Further, after the reflected signal is generated due to the presence of the abnormal point C, there is still another abnormal point C for the outgoing signal after passing through as a transmitted wave, so that a second reflected signal is generated, and further 3 reflected signals, 4th reflected signals, etc. may be generated.
Thirdly, the example of FIG. 1 described above assumes that the delay means 13 is of the third type described above.
That is, it is assumed that both the outgoing signal and the reflected signal are given a delay at the same time. However, the above-described first type and second type delay means 13 are of course possible without depending on such illustrated examples. That is, a type in which only one of the outgoing signal and the reflected signal is delayed can be considered.
Specific examples of the delay constant D are as described above.

<< About the delay circuit 22 >>
Next, the delay line 23 and other delay circuits 22 constituting the delay means 13 of the inspection system 12 will be described with reference to FIG.
The delay means 13 first exerts a delay effect for delaying the signal by a predetermined time with respect to the outgoing signal and reflected signal such as a pulse wave, but with respect to the direct current generated and output by the module 3 of the string 1. Must have no resistance component.
Therefore, as the delay means 13, the delay circuit 22 shown in FIG. 2A and the delay circuit 22 shown in FIG.
The example shown in FIG. 2A is used for both the outgoing signal and the reflected signal as the delay circuit 22 of the third-type delay means 13 described above. On the other hand, in the example shown in FIG. 2B, the delay means 13 can be configured without being restricted by the voltage and current of the solar cell array 7, so that not only the third type but also the first type. It can be used as the first type or the second type. That is, it is possible to use a device that targets only the outgoing signal or the reflected signal.

First, the example shown in FIG. 2 (1) will be described. As described above, an example in which the delay line (delay line) 23 is used as the delay circuit 22 is representative. That is, the delay circuit 22 of the delay means 13 includes a coil 24 and a capacitor 25, and includes a circuit including an inductance L and / or a capacitance C.
In the case of the solar cell array 7, there are many cases in which the metal frame frame or pedestal is not dropped to the ground in construction, but in that case, the capacitance C of the capacitor 25 may change. Therefore, it is important to reliably ground the capacitor 25 in this illustrated example. Further, a capacitor 25 having a withstand voltage in consideration of the output of the string 1 is used.

Next, the example shown in FIG. 2 (2) will be described. As in this example, a delay means 13 using various known delay circuits 22 using a semiconductor or a clock timer in combination with

switches

26 and 27 is also conceivable.
That is, the switch 26 provided on the cable 6 after the parallel branch is normally closed (continuous), and a large current flows during normal power generation and output, whereas it is switched to open (disconnected) when performing the inspection. . On the other hand, the switch 27 provided in the cable 28 further branched in parallel to the delay circuit 22 with respect to the cable 6 is normally opened (disconnected) at the time of power generation and output, but is closed (continuous) at the time of inspection. Is switched to.
Such control of the

switches

26 and 27 is performed by the above-described control unit 19 by remote operation using, for example, wireless or wired (dedicated line or power line). If the switch 27 is provided before and after the delay circuit 22 regardless of the illustrated example, the protection of the delay circuit 22 is further ensured.
The illustrated example has an advantage that various delay circuits 22 can be freely selected because a large current does not flow through the delay circuit 22. Further, when there is a risk of lightning strike, there is an advantage that lightning damage can be minimized by controlling all the

switches

26 and 27 to be opened (disconnected).
The delay circuit 22 is as described above.

《Action etc.》
The inspection system 12 for the solar cell array 7 of the present invention is configured as described above. Therefore, it becomes as follows.
(1) In the solar cell array 7, a plurality of strings 1 including at least one module 3 are connected in parallel.
Thus, the generated and output power is converted from direct current to alternating current via the relay terminal box 4 and the power conditioner 5, and is supplied to demand (see FIG. 4).

(2) And the inspection apparatus 11 of this inspection system 12 consists of a TDR system. That is, an output signal is output and transmitted from the application unit 14 to each string 1 to be inspected via the cable 6, and a reflected signal reflected and reflected from the abnormal point C of the string 1 is measured by the actual measurement unit 15. And received (see (1) in FIG. 1, (1) in FIG. 3, etc.).
And in the discrimination | determination part 16 of the test | inspection apparatus 11, the presence or absence of a failure and other malfunctions is determined based on waveform comparison with an emitted signal and a reflected signal.

(3) Now, in this inspection system 12, the delay means 13 is interposed in the cable 6 of the string 1 connected in parallel ((1) in FIG. 1, (1) in FIG. 2, (2) ) Refer to Figure, (1) Figure in Figure 3).
Then, by interposing the delay means 13 having predetermined different delay constants D, the leading and trailing relations are set in time series for each string 1 with respect to the reflected signal reflected and reflected from the abnormal point C of each string 1. The
Further, the delay time of each delay means 13 can be sequentially input without overlapping the reflected signals by setting the time difference between the shortest arrival time after delay and the non-delay longest arrival time.

(4) Therefore, each reflected signal is sequentially reduced, input, and received by the actual measurement unit 15 of the inspection apparatus 11 in series for each generated string 1 (see FIG. 3 (1)).
Although it is a reflected signal from the string 1 connected in parallel, it is possible to clearly distinguish which string 1 is from. A situation in which the reflected signals overlap and are reduced, input, or received is avoided.

(5) Accordingly, the determination unit 16 of the inspection apparatus 11 can determine which string 1 has the abnormal point C, and that a failure or other malfunction has occurred (FIG. 1 (1), (See (1) in FIG. 3).
Although the strings 1 are connected in parallel, it is possible to easily determine which string 1 has the abnormal point C and is defective.

(6) The inspection system 12 inspects the parallel wiring type solar cell array 7, that is, the string 1 in this way by the TDR method.
This is realized by providing the cable 6 to each string 1 with a delay line 23 and other known delay circuits 22 and using one inspection device 11. That is, it is easily realized by the inspection system 12 having a simple configuration (see FIG. 1 (1) and FIG. 3 (1)).

(7) The inspection system 12 includes the delay means 13 using the delay circuit 22 in the cable 6 of the string 1 as described above.
Therefore, for example, when the current or voltage suddenly increases due to lightning strikes or the like, the components forming the delay circuit 22 (for example, the coil 24 and the capacitor 25 in the example of FIG. 2 (1), the example of FIG. 2 (2)). Then, the switch 26 and the switch 27) immediately burn out.
Therefore, this inspection system 12 is also effective as a countermeasure against surge current and surge voltage.
The operation of the present invention is as described above.

1 string 1 ₁ string 1 ₂ string 2 inspection device (conventional example)
3 module 3 ₁ module 3 ₂ module 4 relay terminal box 5 power conditioner 6 cable 6 ₁ cable 6 ₂ cable 7 solar cell array 8 distribution board 9 load 10 wattmeter 11 inspection device (present invention)
DESCRIPTION OF SYMBOLS 12 Inspection system 13 Delay means 13 ₁ Delay means 13 ₂ Delay means 14 Application part 15 Actual measurement part 16 Discrimination part 17 Switch 18 Switch 19 Control part 20 ₁ Start point 20 ₂ Start point 21 ₁ End point 21 ₂ End point 22 Delay circuit 23 Delay line (Delay line)
24 coil 25 capacitor 26 switch 27 switch 28 cable C abnormal point C ₁ abnormal point C ₂ abnormal point D delay constant D ₁ delay constant D ₂ delay constant T delay time T ₁ delay time T ₂ delay time

Claims

A solar cell array in which a plurality of strings each having one or more modules are connected in parallel, is an inspection system for determining the presence or absence of a failure or other malfunction, and includes an inspection device and a delay unit.
The inspection apparatus determines whether or not there is a defect individually for each string based on the emission signal to each string and the reflected signal from each string,
The delay means sets a priori relationship in time series for each of the strings with respect to one or both of the outgoing signal and the reflected signal, so that the reflected signal from each of the strings is sent to the inspection device. The solar cell array inspection system is characterized in that it functions so as to be input sequentially.
In Claim 1, this inspection device is provided with an application part, an actual measurement part, and a discriminating part, and this application part transmits an outgoing signal to each of these strings via a cable,
The actual measurement unit receives a reflected signal that is reflected and reflected from the abnormal point of each string via the cable, and the discriminating unit performs waveform comparison between the output signal and the reflected signal for each string. Based on the individual, determine whether there is a defect,
The delay means includes a delay circuit, and is interposed in the cable. The reflected signal from each string is input to and received by the actual measurement unit of the inspection apparatus in series for each string. A solar cell array inspection system.
In Claim 2, the delay means is interposed between at least the second and subsequent strings of the cable after being branched in parallel toward the strings,
The delay constant of the delay means is such that the arrival time of one or both of the outgoing signal and the reflected signal between each string and the actual measurement unit of the inspection apparatus is made different for each string, and thus the time series between the signals is different. The inspection system for a solar cell array, comprising: a value for sequentially setting a first and a second relationship.
A solar cell array in which a plurality of strings each including one or more modules are connected in parallel, is an inspection system that determines the presence or absence of a failure or a malfunction, and an application unit that applies an emission signal to the plurality of strings; An actual measurement unit that actually measures the reflected signal from the string, and a determination unit that determines the presence or absence of a failure or malfunction of the solar cell array based on the reflected signal,
An inspection system, further comprising delay means for delaying arrival of the reflected signal to the actual measurement unit and setting a prior relationship of the plurality of reflected signals.
The application unit is connected to a point farther from the string than a branch point of the plurality of strings connected in parallel;
The delay means is connected between the branch point and at least one of the plurality of strings, and delays either one or both of the emission signal and the reflection signal to the measurement unit. The inspection system according to claim 4, wherein arrival of the reflected signal is delayed.
The delay means has a shortest arrival time after delay of a reflected signal from the point closest to the actual measurement section of the string to which the delay means is connected to the actual measurement section of the string to which the delay means is not connected. The inspection system according to claim 5, wherein the reflected signal is delayed so as to be later than a non-delay longest arrival time of the reflected signal from the point farthest to the actual measurement unit.
A plurality of the delay means connected to the different strings;
The inspection system according to claim 6, wherein the delay time of each of the delay means is equal to or greater than the time difference between the shortest arrival time after delay and the non-delay longest arrival time.