JP6721959B2 - Photovoltaic generator inspection method - Google Patents

Description

The present invention relates to a method for inspecting a solar power generation device.

In recent years, the spread of solar power generation devices has been increasing. The solar power generation device is a device that generates direct current electromotive force by irradiating the semiconductor layer with solar energy, converts the electromotive force into alternating current, and uses the alternating current. For this reason, it is said that the solar power generation device does not require a rotating machine in principle, and thus is not likely to fail and is capable of stable power generation for a long period of time.

However, as the use of photovoltaic power generators progresses, it has been reported that the panel itself has an initial failure, a failure during construction, and a failure due to a disconnection or the like. Therefore, it is required to detect such a defect early.

Known methods for inspecting defects include a method in which an inspector visually checks the light receiving side of a panel (also called a "module") to find a discolored portion, or a method in which a tester is connected to each panel to search for abnormal current values. Has been. However, such a method requires a great deal of work to find a defective solar panel. In recent years, a large-scale solar power generation device called mega solar has also become widespread.When inspecting such a large-scale solar power generation device, such an inspection method requires an extremely large amount of time and labor. I need it.

Therefore, a system has been proposed in which each panel is provided with communication means, and the result of measuring the electrical characteristics of each panel is transmitted from this communication means to the control device, so that the failed solar panel can be easily confirmed. (See, for example, Patent Document 1 below).

JP, 2004-221479, A

However, in the above-mentioned configuration, it is necessary to provide a communication means for each panel, which causes a great cost to introduce the system.

An object of the present invention is to provide a method for easily inspecting a solar power generation device including a solar array in which a plurality of panels having no communication means are arranged while having high reliability.

The present invention is a method for inspecting a photovoltaic power generation device, which comprises a string in which a plurality of panels are connected in series, the solar array including a plurality of parallel connected arrays.
A step (a) of detecting an abnormal string using the first inspection device,
A step (b) of measuring a heat generation state of a plurality of panels included in the string of the abnormal state detected in the step (a);
Based on the result of the step (b), the heat generation state of the specific panel included in the string in the abnormal state is greater than or equal to the threshold value than the heat generation states of the panels other than the specific panel included in the string in the abnormal state. And (c) determining that the specific panel is in an abnormal state when it is confirmed to be high,
Based on the result of the step (b), if it is not confirmed that the heat generation state of the specific panel is higher than the threshold value of other panels, the second inspection device is used to scan the string of the abnormal state. By including a step (d) of identifying a panel in an abnormal state from a plurality of panels included in the string in the abnormal state,
In the step (a), the abnormality is detected based on a time period from when the first inspection device emits a predetermined emission signal to each string to when the first inspection device receives a reflection signal from each string. Is the process of detecting the state string,
In the step (c), the magnetism generated from each panel included in the string in the abnormal state is detected by the second inspection device in a state where the string in the abnormal state is energized and detected. It is characterized in that it is a step of identifying the panel in the abnormal state based on magnetic information.

According to the above method, the abnormal state can be grasped on a string-by-string basis by a simple method in the step (a). The abnormal string includes the abnormal panel. An abnormal panel often generates heat due to the operation of the bypass diode. Therefore, by measuring the heat generation state of the panel included in the string in the abnormal state, if there is a panel in which heat generation is significantly advanced as compared with other panels, the panel can be recognized as the abnormal state. ..

However, in winter or in bad weather, a significant temperature difference may not be confirmed between a normal panel and an abnormal panel. Further, depending on the installation location of the panel, it may be difficult to measure the temperature. Note that when the number of panels is large, it is difficult to measure the temperature in panel units, so the temperature condition is measured collectively in a plurality of panel units. At this time, it is impossible to pinpoint the location of heat generation.

However, according to the above method, when the abnormal panel cannot be identified by detecting the heat generation state, the abnormal panel is identified by the magnetic detection. No magnetic field is emitted from a defective panel or is extremely small compared to the magnetic field generated from a normal panel. Therefore, the panel in the abnormal state can be specified by detecting the magnetic signal.

However, since this second inspection apparatus is configured to measure the amount of magnetic field in panel units, if this step (d) is executed for all the panels included in the array, the amount of work becomes extremely large. I will end up. Therefore, first, in step (a), the string including the panel in the abnormal state is specified. The step (a) can be realized by simply transmitting and receiving a predetermined signal to and from each string from the first inspection device, so that the step (d) is performed in an extremely short time as compared with the case where the step (d) is executed for all the panels. Can be achieved with.

Further, the step (b) of measuring the heat generation state can be measured in units of a plurality of panels. Therefore, the amount of work required to specify the panel in the abnormal state from the panels included in the string can be smaller than that in the step (d). Therefore, in the present invention, first, the abnormal panel is specified by measuring the heat generation state.

Then, when the abnormal panel cannot be specified based on the result of the heat generation state measured in the step (b), the abnormal panel is specified in the step (d). As a result, it is possible to reliably identify the panel in the abnormal state while reducing the total work amount.

In addition, the step (b) includes a step of photographing a plurality of panels included in the string in an abnormal state by a thermo camera,
The step (c) may include a step of making a determination based on data taken by the thermo camera.

ADVANTAGE OF THE INVENTION According to this invention, the solar power generation device containing the solar array which has arrange|positioned the panel which is not provided with the communication means can be easily inspected while having high reliability.

It is a schematic diagram which shows an example of a solar power generation device. It is a flowchart explaining the inspection method of the solar power generation device of this invention. It is a block diagram which shows a 1st inspection apparatus typically. It is an example of a photograph and a captured image showing a situation in which the temperature of the panel is measured using a thermo camera. It is drawing which shows the structure of a 2nd inspection apparatus typically.

First, an outline of a solar power generation device that is a premise of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing an example of a solar power generation device.

The solar power generation device 1 includes a solar array 11. The solar array 11 includes a string 15 in which a plurality of panels 13 connected in series are arranged in parallel. The panel 13 has a pn-junction semiconductor layer, and a direct current is generated when it is irradiated with sunlight. This DC current is supplied to the power conditioner 21 via the terminal box 19 by the cable 17 for each string 15. The power conditioner 21 converts this direct current into alternating current.

The alternating current converted by the power conditioner 21 is consumed by the load 25 after passing through the distribution board 23. The surplus power that has not been consumed is supplied as a reverse flow to the commercial power system via the power meter 27.

In addition, in FIG. 1, the case where the solar array 11 is mounted on the roof is shown as an example, but the present invention is not limited to this mode.

FIG. 2 is a flowchart illustrating the method for inspecting the solar power generation device of the present invention. First, the string 15 in an abnormal state is detected by the first inspection device (step S1). Step S1 corresponds to step (a). If no abnormal string 15 exists, the test ends.

When the string 15 in the abnormal state is found in step S1, the heat generation states of the plurality of panels 13 included in the string 15 in the abnormal state are measured (step S2). Step S2 is performed by photographing the plurality of panels 13 included in the target string 15 with a thermo camera, for example. This step S2 corresponds to the step (b).

Next, it is detected whether or not there is a panel 13 that is significantly heated compared to the other panels 13 among the plurality of measured panels 13 (step S3). When the panel 13 is present (Yes in step S3), the panel 13 is determined to be in an abnormal state, and the inspection is finished. Step S3 corresponds to step (c).

In the step S3, when the panel 13 which is significantly heated compared to the other panels 13 is not confirmed (No in the step S3), the target string 15 is scanned by using the second inspection device ( Step S4). Thereby, the panel 13 in the abnormal state is specified from the plurality of panels 13 included in the string 15 in the abnormal state. This step S4 corresponds to the step (d).

The details of step S1 will be described below.

FIG. 3 is a block diagram schematically showing an example of the first inspection device used in step S1. The first inspection device 30 includes a signal generation unit 31, a reception unit 32, a determination unit 33, and a switching unit 34. The signal generator 31 generates an input signal and applies it to the string 15 to be inspected. The receiving unit 32 applies the input signal to the string 15 and then receives the signal reflected from the string 15. The determination unit 33 diagnoses the failure location of the string 15 from the signal received by the reception unit 32. The switching unit 34 switches the connection between the signal generation unit 31 and the reception unit 32 between the positive electrode 15a and the negative electrode 15b of the string 15 based on a control signal from a control unit (not shown). The switching unit 34 also includes an attenuator 35.

The pole on the opposite side to the pole to which the signal generating unit 31 and the receiving unit 32 are connected is connected to the attenuating unit 35, or the attenuator 35 is not connected and is an open end. When the input signal reaches the open end, a reflected wave is generated. A reflected wave is also generated when the input signal reaches the failure point in the string 15. On the other hand, the signal reaching the attenuator 35 is attenuated and no reflected wave is generated.

The determination unit 33 includes a memory and a calculation unit. The distance (string length) from the positive electrode 15a of the string 15 to the negative electrode 15b is stored in the memory. The computing unit computes and estimates the distance from the positive electrode 15a or the negative electrode 15b to the failure location based on the time when the signal is received by the receiving unit 32. An example of a specific method of identifying a failure location in the string 15 is shown below.

First, the switching unit 34 connects the signal generating unit 31 and the receiving unit 32 to either the positive electrode 15a or the negative electrode 15b of the string 15. Next, the signal generator 31 generates an input signal and applies it to the string 15. If the string 15 is normal, the applied input signal is reflected at the pole of the string 15 opposite to the input pole. On the other hand, if there is a failure somewhere in the string 15, the input signal is reflected at the failure location.

The receiver 32 receives the reflected signal. The determination unit 33 calculates the time T1 from the application of the input signal to the observation of the output signal based on the time when the signal generation unit 31 outputs the signal and the time when the reception unit 32 receives the signal.

Next, the switching unit 34 connects the connection destinations of the signal generation unit 31 and the reception unit 32 to the pole on the opposite side of the pole of the string 15. Then, similarly, the signal generator 31 generates an input signal and applies it to the string 15, and the receiver 32 receives the reflected wave. The determination unit 33 calculates the time T2 from the application of the input signal to the observation of the output signal based on the time when the signal generation unit 31 outputs the signal and the time when the reception unit 32 receives the signal.

Then, when T1 and T2 are different from each other, the determination unit 33 determines that there is a failure point in the string 15. Then, the determination unit 33 calculates the distance X from the pole to which the signal is first input to the failure location based on the length L×T1/(T1+T2) of the string 15 to estimate the failure location.

When T1 and T2 are equal, there are two possible cases, where there is no fault in the string 15 or there is a fault just in the center of the string 15. Therefore, when T1 and T2 are equal, the switching unit 34 connects the attenuation unit 35 to the opposite pole of the string 15 while leaving the connection destinations of the signal generation unit 31 and the reception unit 32 unchanged. In this state, the signal generator 31 generates an input signal and applies it to the string 15. At this time, when the receiving unit 32 receives the reflected wave, the determining unit 33 determines that the failure portion exists in the string 15, more specifically, near the center of the string 15. On the other hand, when the receiving unit 32 does not receive the reflected wave, it is considered that the signal has advanced to the end and then attenuated by the attenuating unit 35. Therefore, the determining unit 33 determines that the string 15 does not have a failure portion. to decide.

When the distance from the end of the string 15 to the failure location is roughly estimated in step S1, the panel 13 existing at the location is almost specified. However, since the evaluation is based on the delay time of the signal, there is a high possibility that an error exists. Therefore, the temperature state of the panel near the specified panel 13 is evaluated in step S2. FIG. 4 is a photograph showing an example of a situation in which the temperature of the panel 13 is measured using a thermo camera and an example of a captured image thereof. As shown in FIG. 4A, the worker images the vicinity of the specified panel 13 as a subject using a thermo camera. When heat generation is confirmed, as shown in FIG. 4B, since the chromaticity is significantly different as compared with other regions, a heat generation site is confirmed. FIG. 4B is originally a color image, and a portion where the temperature is extremely high is red. In FIG. 4B, a black-and-white image is converted, but a portion displayed in a darker color than the surroundings is confirmed. This region is a region in which the temperature is significantly higher than the surrounding area.

In this step S2, if a panel having a temperature clearly higher than that of the adjacent panel is confirmed, it can be determined that the panel is in an abnormal state. However, in winter or in bad weather, a significant temperature difference may not be confirmed between a normal panel and an abnormal panel.

Therefore, step S4 of inspecting each panel in the target string 15 using the second inspection device is additionally performed. The details of step S4 will be described below.

FIG. 5 is a drawing schematically showing the structure of the second inspection device 40. The second inspection device 40 includes a head portion 42 having a built-in magnetic detection portion 41, and a handle portion 43 having the tip portion connected to the head portion 42. The handle part 43 has, for example, a hollow structure, and the determination part 44, a power supply unit, and the like are built in the hollow part.

The magnetic detection unit 41 is configured to detect a magnetic fluctuation due to the energization of the panel 13, and includes, for example, a magnetoresistive element. The magnetic detection unit 41 includes the magnetic detection element 11 that can detect the magnetic flux density. An example of a specific method of identifying a failure location in the string 15 is shown below.

First, the second inspection device 40 scans each panel 13 included in the target string 15. Specifically, with the operator holding the handle portion 43, the head portion 42 is brought into contact with the protective surface of the panel 13, and the panel 13 is moved from one side to the other side. As a result, the magnetic detection unit 41 mounted on the head unit 42 detects the magnetism in each panel 13.

The magnetic detection unit 41 outputs a voltage by detecting a change in magnetism. The determination unit 44 recognizes the magnetic distribution in the panel 13 based on the change in the voltage, and compares the magnetic distribution with the magnetic distribution stored in advance in the normal state of the panel 13. Then, when the magnetic distribution greatly differs from the magnetic distribution stored in advance, the determination unit 44 determines that the panel 13 is out of order.

[Other embodiment]
In the inspection method of the present invention, step S1 of identifying a string including a panel in an abnormal state, step S2 of detecting a heat generation state of a panel included in the identified string, and a panel in an abnormal state cannot be identified from the heat generation state. In this case, the content has a step S4 of identifying a panel in an abnormal state in the string by detecting magnetism. That is, the configurations of the first inspection device 30 used in step S1 and the second inspection device 40 used in step S5 described above are merely examples, and the present invention is limited to the case of using this device. Absent.

1: Photovoltaic power generator 11: Solar array 13: Panel 15: String 15a: String positive electrode 15b: String negative electrode 17: Cable 19: Terminal box 21: Power conditioner 23: Distribution board 25: Load 27: Electric power Total 30: First inspection device 31: Signal generation part 32: Reception part 33: Judgment part 34: Switching part 35: Attenuation part 40: Second inspection device 41: Magnetic detection part 42: Head part 43: Handle part 44: Judgment Department

Claims (2)

A string formed by connecting a plurality of panels in series, a method for inspecting a photovoltaic power generation device including a solar array configured by being connected in parallel,
A step (a) of detecting an abnormal string using the first inspection device,
And (b) measuring the heat generation states of a plurality of panels included in the string in the abnormal state detected in the step (a) only when the string in the abnormal state is detected in the step (a). ,
Based on the result of the step (b), the heat generation state of the specific panel included in the string in the abnormal state is greater than or equal to the threshold value than the heat generation states of the panels other than the specific panel included in the string in the abnormal state. And (c) determining that the specific panel is in an abnormal state when it is confirmed to be high,
Based on the result of the step (b), if it is not confirmed that the heat generation state of the specific panel is higher than the threshold value of other panels, the second inspection device is used to scan the string of the abnormal state. By including a step (d) of identifying a panel in an abnormal state from a plurality of panels included in the string in the abnormal state,
In the step (a), the abnormality is detected based on a time period from when the first inspection device emits a predetermined emission signal to each string to when the first inspection device receives a reflection signal from each string. Is the process of detecting the state string,
In the step ( d ), the magnetism generated from each panel included in the string in the abnormal state is detected by the second inspection device in a state where the string in the abnormal state is energized and detected. A method for inspecting a photovoltaic power generation device, comprising the step of identifying the panel in the abnormal state based on magnetic information. The step (b) includes a step of photographing a plurality of panels included in the string in an abnormal state with a thermo camera,
The method for inspecting a photovoltaic power generation device according to claim 1, wherein the step (c) includes a step of making a determination based on data taken by the thermo camera.