Photovoltaic system with detection of proximity, intrusion, degradation or theft, and corresponding method

Abstract

Photovoltaic system with proximity and / or intrusion detection functions, implemented by monitoring the photovoltaic current or a purposefully injected reverse current. The system comprises photovoltaic panels connected to measuring devices capable of recording the photovoltaic current and / or the reverse current with a temporal resolution sufficient for identifying shading caused by the approach of a person.

Description

Photovoltaic system with proximity, intrusion, damage or theft detection and corresponding process technical field

[0001] The present invention relates to a modular system enabling the easy maintenance of photovoltaic systems, by detecting damage, theft, or obstruction on a photovoltaic panel. State of the art

[0002] Photovoltaic installations are already of significant importance, and their numbers continue to grow thanks, among other things, to the ever-decreasing price of silicon solar panels and the increasing need for renewable energy sources. However, solar installations remain visually imposing and occupy large areas. Aside from rooftops, it is difficult to find suitable premises for new installations.

[0003] These drawbacks can be overcome by multi-purpose photovoltaic systems that combine other functions with energy production. This is sometimes required by law and local regulations. Therefore, there is a need for a solar product that enables the creation of efficient and economical solar installations. For example, vertical photovoltaic module installations are used to delineate spaces, create fences, parking lots, and along roadsides, among other applications. Bifacial photovoltaic panels are particularly well-suited to these applications.

[0004] Multipurpose photovoltaic installations, however, present special challenges. Among other things, many multipurpose installations are easily accessible, unlike rooftop installations. It is therefore essential to protect the panels from damage. caused by collisions or acts of vandalism. When the installation is used to delimit and enclose a place, it is also necessary to control unauthorized access. Brief summary of the invention

[0005] There is therefore a need for a solar product to protect solar installations accessible to the public and to control access, detect the proximity of intruders or thefts or vandalism which degrade the performance of photovoltaic panels.

[0006] These goals are achieved by the subject matter of the attached claims and in particular by a photovoltaic installation comprising a plurality of vertical flat photovoltaic panels, preferably bifacial, each photovoltaic panel being associated with an electronic energy management module configured to measure a photovoltaic current generated by the photovoltaic panel and its evolution over time, the installation comprising an alarm circuit configured to compare the measured photovoltaic current with an expected photovoltaic current and generate a proximity alarm on the basis of a difference between the measured photovoltaic current and the expected photovoltaic current.

[0007] The objectives are also achieved by the method which is the subject of the corresponding category claim, namely a method for detecting proximity to a photovoltaic panel, comprising measuring a photovoltaic current generated by the panel, comparing the measured photovoltaic current with an expected photovoltaic current, and generating an alarm based on a difference between the measured photovoltaic current and the expected photovoltaic current.

[0008] This device and method allows the approach of a person (or vehicle or other extended body) to be detected by the shadow cast on the panel or, in the case of diffuse lighting, the reduction in light intensity caused by the approach of an opaque body.

[0009] The auxiliary claims introduce useful and advantageous features, but not indispensable or essential to the operation of the invention, for example, a structure in which the photovoltaic panels are arranged in modules, each comprising two poles connected to each other by a first crossbar and a second crossbar orthogonally; one, two, or more vertical photovoltaic panels between the poles with a free space between them housing the electronic energy management modules, which may be covered by a cover. The vertical free space in the middle of the panels allows for the installation of a second identical or compatible photovoltaic module at a right angle.An electrical circuit between the poles advantageously allows for the electrical connection of adjacent photovoltaic modules in a daisy chain, with the appropriate temporal resolution for detecting approaches or intrusions: preferably, the photovoltaic current is measured with a resolution better than 5 minutes, preferably better than 30 seconds, and ideally, approximately 1 second. For the purposes of this document, the temporal resolution of the current measurement and its sampling rate can be considered interchangeable terms.

[0010] The expected photovoltaic current is either the photovoltaic current generated by an identical photovoltaic panel located away from any obstacles under similar sunlight conditions, or the expected photovoltaic current derived from a simulation. The alarm signal can be limited to events in which the difference between the measured and expected photovoltaic current increases sharply within a predetermined time interval.

[0011] The description and claims use the terms "vertical" and "horizontal" to indicate the usual orientation of the photovoltaic module when installed.

[0012] The description and claims refer in several places to a photovoltaic current. However, optimizers exist that are configured to measure and transmit instantaneous photovoltaic power rather than instantaneous photovoltaic current. It should be understood that the generated photovoltaic power could be used instead of the photovoltaic current without significant changes. Within the scope of this invention, these two quantities are equivalent and interchangeable.

[0013] Vertical orientation and the use of bifacial panels, while interesting, are not essential features. The invention can also be applied to horizontally mounted photovoltaic installations. In this case, the installation of the invention can detect the presence of foreign bodies on the surface of the panels. One example among others is that of solar installations in wind farms. The alarm generated by the invention can signal birds falling onto the panels. This disclosure will only cover a modular installation of vertical panels, for the sake of brevity. It is understood that this specific example is not a limitation of the invention, which is defined by the wording of the appended claims.

[0014] The measurement of photovoltaic current makes it possible to detect the proximity of a person by the reduction of the current linked to the projected shadow or, in diffuse lighting conditions, to the presence of an opaque body nearby.

[0015] When natural light is insufficient to generate adequate photovoltaic current, for example at night, a reverse current can be injected into the panels and its variations monitored. This operating mode does not detect the approach of people or opaque objects, but it does detect impacts with the photovoltaic panels, as well as the disconnection or theft of a photovoltaic panel. The constant current is abruptly interrupted when the panel is removed or damaged.

[0016] This detection method can be advantageously combined with the subject matter of the main claim, or it can be an independent invention, the object of which is a system equipped for detecting vandalism or theft of panels by monitoring a reversed electric current intentionally injected into the panels, or a method for generating an alarm comprising injecting and measuring a reversed current through the photovoltaic panel when the photovoltaic module is in darkness, and activating the alarm signal when sudden variations (on a time scale of a few minutes, 30 seconds, one second, or a fraction of a second) in the measured reversed current are observed. The measurement of the reversed current can be obtained by networked optimizers or microinverters, as in the preceding variants. Brief description of the figures

[0017] Examples of implementation of the invention are given in the description illustrated by the accompanying figures, in which: Figure 1 illustrates a photovoltaic module according to the invention. Figure 2 illustrates three photovoltaic modules installed adjacent to each other. Figures 2A and 2B are two cross-sections of the installation in Figure 2, showing electrical cable management and guidance devices. Figure 3 shows two photovoltaic modules assembled and connected in a cross shape. Figures 4-5 illustrate two methods used within the framework of the invention to detect intrusions or approaches. Example(s) of a method of implementing the invention

[0018] Figure 1 shows a photovoltaic module 15 according to the invention, seen from the front. The module comprises two vertical poles 31a, 31b connected by two cross members 32 and 34, one upper, between the tops of the poles, and the other lower, close to and parallel to the ground.

[0019] In the space delimited by the posts 31a, 31b, the first crossbeam 32 and the second crossbeam 34 are placed vertically two photovoltaic panels 21, preferably bifacial, so that the photovoltaic module 15 is ready to generate electricity when installed vertically.

[0020] The photovoltaic panels 21 are preferably separated in the middle by a free space 18, essentially aligned with a vertical axis 25 equidistant from the posts 31a, 31b. One could also imagine variants in which the slot 18 is not symmetrically centered between the posts, for example with a slot attached to one of the two posts.

[0021] The free space 18 between the panels, if present, allows for the installation of energy management devices 80, such as optimizers or micro-inverters. In a mixed-use photovoltaic system, it is impossible to guarantee that all the photovoltaic panels receive the same amount of sunlight. It is therefore advantageous for each panel to have its own management devices 80 configured to optimally transmit the generated energy to a common circuit, even when some of the panels are less illuminated or even shaded. The space 18 between the solar panels can also be used to accommodate other technical components, such as a connector 83 for battery charging.

[0022] Although advantageous, it is not essential to provide a free space between two photovoltaic panels. The invention also includes variants without free spaces, or with a free space adjacent to a posts 31a, 31b. The number of photovoltaic panels per module is also not limited to two: each module can contain one, two, three, four, or any number of photovoltaic panels. The management devices 80 and / or the charging connector 83 can be attached to one of the posts 31a, 31b, or to one of the cross members 32, 34, for example.

[0023] The free space 18 between the panels can also be used for other devices, for example information panels, communication devices, energy meters or other, as required.

[0024] The control devices 80 are preferably mounted on removable mounting bars 85 or other removable supports and can be moved during installation. As will be seen later, this allows, in certain embodiments of the invention, for two identical or compatible modules to be interlocked in a cross configuration. The module dimensions can vary as required. In a typical case, the width of a photovoltaic module 15 can be 2.4 m, of which 0.3 m is occupied by the central slot 18.

[0025] Module 15 also includes a pre-installed electrical circuit 65 running from one post to the other, allowing for the easy connection of multiple compatible modules placed side-by-side. The electrical circuit 65 preferably runs along the second lower cross member 34.

[0026] Figure 2A shows an (optional) cable guidance and management system integrated into the cross member 34, corresponding to section AA of Figure 2. A guide 69, preferably metallic, is fixed under the cross member 34 and guides the conductors 65a, 65b from one end to the other. Longitudinal partitions can be provided to separate the cables according to their function or voltage level. For example, 240V AC cables and low-voltage DC cables, or Communication cables. The number of compartments and partitions is unlimited. A cover 66 allows access, for example to permit maintenance operations.

[0027] Between two photovoltaic modules 15, the conductors 65a, 65b can be covered by covers 67, preferably metallic, visible in Figure 2B, corresponding to section BB of Figure 2. The covers 67 protect and conceal the cables 65a and 65b and are removably fixed to the upper supports 40. The connection between one module and the other can be made using connectors, either in the covers 67 or in the guide 69. The separation of the circuits at the pole can be achieved using the two front / rear sides, as illustrated, or by partitions.

[0028] The posts are configurable to connect with posts of identical or compatible modules, allowing for the creation of alignments. In the variant shown, post 13b (on the right in the figure) has a lower bracket 44 with a vertical axis 46. The axis 46 is configured to engage in a correspondingly shaped cavity in post 13a of another photovoltaic module. The clamps 48 secure the modules together and can also serve as lifting handles.

[0029] Figure 2 illustrates an alignment of three identical photovoltaic modules 15 and a narrower extension module 16 connected together as described above. The slots 18 housing the control modules 80 are covered by covers 37 which serve to protect and conceal the modules 80 and may also have a noise-dampening function. For this application, which does not involve cross-connections, the central electrical elements 80 and the covers 37 can be fully pre-assembled. In the example shown, the covers 37 have openings to allow the use of charging connectors.

[0030] Optionally, shims 40, 41 above and below brackets 44 can compensate for uneven ground. Preferably, the lower shims 41 also incorporate a conduit for the electrical circuit 65 mentioned previously. Advantageously, two adjacent posts share a common foundation 50. Foundations screwed directly into the ground, concrete, or any suitable foundation method may be used.

[0031] Figure 3 shows two identical photovoltaic modules connected in a cross configuration. The cylindrical cover 37 is partially transparent to allow the energy management modules 80 inside to be seen. In this configuration, the mounting bars 85 and the cover 37 are removable, so that the electrical devices 80 can be installed only after the modules 15 have been cross-connected, in the central void. The cross members 32 have retractable elements 38 that allow an opening to be created and two modules to be nested. Other arrangements are also possible.

[0032] As we have seen, the photovoltaic modules of the invention allow for the construction of a wide variety of structures, such as fences, parking lots, shelters, etc., in which the photovoltaic modules act as barriers. In many cases, it is desirable to monitor these structures and generate a proximity signal when a person approaches or attempts to cross these barriers.

[0033] It has been observed that the photovoltaic current generated by a vertical solar panel is sensitive to the approach of people or opaque objects. Under direct lighting conditions, the current is reduced almost proportionally to the area of ​​the shadow cast on the panel. In indirect lighting situations, a reduction in the incident light intensity on the panels is always observed when an opaque object is sufficiently close. Even in these cases, a decrease in the photovoltaic current is observed. Furthermore, the approach of a person or opaque objects can also be detected by observing a decrease in the electrical voltage across the solar panel or in the electrical power generated.

[0034] Energy management devices, such as optimizers or microinverters, are equipped to measure the photovoltaic current and / or electrical voltage and / or power generated at any given moment and can transmit this information to a central server configured to analyze these variables and their evolution over time, detect the approach of people, and, if necessary, generate an alarm signal. Many optimizers or microinverters have a data interface, such as an Ethernet or serial interface, which can be used for this purpose.

[0035] The alarm server implements an algorithm that tracks, with fine time resolution (e.g., with a cadence of 5 minutes, 30 seconds, 1 second or less, depending on the technical capabilities of the optimizers or micro-inverters), the production of each panel or a string of panels with similar orientations and shading configurations.

[0036] The generated photovoltaic current can change not only due to the approach of an intruder, but also for other accidental reasons. For example, current reductions can be expected throughout the day due to clouds passing in front of the sun, or shadows cast by distant objects such as buildings or trees. The same applies to the voltage and power generated.

[0037] The following description will refer to a measurement of photovoltaic current only, for the sake of brevity. However, this should not be interpreted as a limitation of the invention. The examples that follow naturally extend to cases where the electrical quantity whose change signals the approach of a person or an opaque object is a voltage across the terminals of the photovoltaic panel or an electrical power generated by the photovoltaic panel.

[0038] To distinguish between accidental changes in photovoltaic current and the approach of people, the invention can compare the measured photovoltaic current with an expected photovoltaic current, namely the current that would be generated by a given photovoltaic panel under the current lighting conditions, without any approaching person. This avoids false alarms generated, for example, by passing clouds. If a panel deviates from the average corrected for any adjustments, a temporary production anomaly can be detected, and the alarm can be triggered. The same approach applies to detecting approach by comparing the expected photovoltaic voltage or power with the actually measured value.

[0039] The expected photovoltaic current can be the result of a measurement; for example, it can be obtained by measuring the current generated by a reference photovoltaic panel, identical or similar, with the same orientation. When an installation includes multiple identical panels with the same orientation, they can serve as a mutual reference.

[0040] Furthermore, photovoltaic installations can also have panels at different heights. The higher-mounted panels can then be used as a reference, as they are less affected by the approach of people. In this case, the invention can extrapolate the output of a high-mounted panel to obtain the expected photovoltaic current / voltage / power for a panel at ground level, and thus detect the approach of a person or an opaque object.

[0041] Figure 4 illustrates, in an idealized way, a proximity detection method as described and claimed. Step 93 is the measurement, for a given photovoltaic panel, of the photovoltaic current lp (or, equivalently, the instantaneous photovoltaic power). This current is compared with the expected current l s (step 95) and test 97 generates an alarm signal 100 if necessary.

[0042] The expected photovoltaic current can also be the result of a calculation or simulation, using one or more of the following input variables: time, sun position, cloud cover, the photovoltaic currents generated by all the photovoltaic panels in the installation at a given time, or data from environmental sensors, such as irradiance probes. Abnormal current variations can then be detected with excellent reliability. In a simplified version, the expected current can be a predetermined average current.

[0043] The algorithm can establish a reference profile for each panel (or group of panels) based on historical data, from previous days or possibly years, and adjust it with respect to environmental data, for example the output of an irradiation probe.

[0044] The method of the invention can also exploit the special temporal structure of the current signals caused by an approach. While clouds or shadows cast on panels due to the apparent movement of the sun are gradual and of considerable duration, the approach of a person is characterized by sudden, short-duration variations, limited to a single photovoltaic panel or a small group of adjacent panels. The installation will therefore be equipped to measure the current generated individually by each panel (or by each small group of panels) at time scales short enough to detect the shadow cast by an approaching person. Typically, a resolution better than five minutes is sought, preferably thirty seconds, or even more preferably one second or less.

[0045] Compared to conventional monitoring systems, which focus on comparing strings, inverters, or the entire installation against desired output over much longer timescales—for example, hours or a full day—and whose purpose is not to detect proximity but to verify the proper functioning of the installation, this invention attempts to detect rapid variations in photovoltaic current caused by the approach of a person, damage to the panel due to vandalism, or a panel being disconnected. Several ways can be conceived to define a current variation as "rapid" in the invention. The alarm circuit generates an alarm signal, for example, when the variation in the difference over a predetermined time interval exceeds a previously established threshold.Similarly, digital or analog filters, or an infinite number of electronic circuits, can be used to compare the photovoltaic current with the expected current and generate an alarm when there is a sudden change in their difference. The invention can also use systems based on artificial intelligence, for example, neural networks, specially trained for this purpose. The time interval over which the current variation is measured can be set to 5 minutes, or one minute, 30 seconds, 20 seconds, 10 seconds, 5 seconds, one second, or less.

[0046] The algorithm's sensitivity can be fine-tuned through a calibration process, for example, by intentionally creating shading. Calibration is preferably independent for each panel. Special calibrations can also be used for different times of day and seasons to improve the algorithm's reliability. Alternatively, artificial intelligence systems can be used, trained to generate the expected photovoltaic current for each panel at any given time, based on all available input variables.

[0047] Based on the results, we can estimate elements such as the size or nature of the nearby object and categorize alarms according to predefined classes. By comparing signals from adjacent panels, we can It can also detect the movement, or speed of the object, and adapt the generated automatic response.

[0048] During operation, thanks to the fine monitoring of the power generated by the panel and its comparison with reference profiles, it is possible to identify a production anomaly and then the presence of an object or person near the fence, through the direct or indirect shading created: detection of a production anomaly compared to the reference, and comparison with any standardized anomalies to identify the magnitude of it.

[0049] The algorithm then transmits a dedicated alarm to the monitoring system, identifying if possible the type of obstacle, in all cases the panel, and therefore the monitored shade site.

[0050] It is therefore possible to detect a person, a person climbing the barrier, damage to the sign, theft of the sign, a poster, an animal (a deer / wild boar / dog wishing to pass or especially a bird that may have been injured in a horizontal mode also useful for the innovation of solar wind turbines)

[0051] By identifying a shift in the production anomaly on adjacent panels, it is also possible to detect and discriminate the movement of an object (agricultural or maintenance equipment, person, animal).

[0052] In the case of signs at the edge of a street or sidewalk, it is possible to specifically disable the detection of certain signs.

[0053] The inventors verified that a solar panel can withstand a considerable reverse current without damage. It is possible to apply a slight reverse current, or reverse potential, even at night to validate the integrity of the electrical chain connected by the solar modules. The reverse current will be measured and monitored with fine temporal resolution (by (Example with a cadence of 5 minutes, preferably 30 seconds, better yet, about 1 second). This can be done using the same optimizers or micro-inverters mentioned above.

[0054] Close monitoring of the current flowing through the panels makes it possible to identify a change in resistance (damage to a panel) or an open circuit (theft or major damage to the panel).

[0055] Figure 5 illustrates, in an idealized manner, a proximity detection method as described and claimed. Step 92 is the measurement of the reverse current for a given photovoltaic panel. A sudden change to an abnormal value of the reverse current, far from the panel's nominal reverse current value, is considered an indication that a photovoltaic panel has been damaged or stolen, and generates an alarm (step 94).

[0056] This reverse current detection method only activates in the event of theft or damage to the panel, or at most, when the panel is subjected to a sufficiently strong impact to disrupt the reverse current, at least momentarily. However, it is also effective at night and in the dark. It can be combined with photovoltaic current monitoring-based detection, or used alone. Reference numbers used on the sheets

[0057] 15 photovoltaic modules 16 reduced module 18 space, slot 21 photovoltaic panels 25 vertical axis 31a, b post 32 first crossing 34 second cross member 37 cover 38 retractable closure 40 high wedge 41 low wedge 44 bracket 46 axle 48 clamps 50 screw foundation 65 electrical circuit 65a cables 65b cables 66 cover 67 cover 69 cable guide 80 energy management device 83 charging station 85 bracket 89 charging cable 92 reverse current measurement 93 photovoltaic current or power measurement 94 comparison with expected value 95 comparison with expected value 96 test 97 test 100 alarm

Claims

Demands 1. Photovoltaic installation with proximity, intrusion, damage or theft detection, comprising a plurality of photovoltaic panels (15), each photovoltaic panel being associated with an electronic energy management module (80) configured to measure a photovoltaic current (Ip) generated by the photovoltaic panel (15) and its time evolution, the installation comprising an alarm circuit configured to compare the measured photovoltaic current with an expected photovoltaic current (Is) and generate an alarm based on a difference between the measured photovoltaic current (Ip) and the expected photovoltaic current (Is).

2. Photovoltaic installation according to the preceding claim, wherein the alarm circuit is configured to detect variations in photovoltaic current (Ip) with a time resolution better than 5 minutes, preferably better than 30 seconds, more preferably a time resolution of one second or less, and the alarm signal is generated when the difference between the measured photovoltaic current and the expected photovoltaic current increases within a predetermined time interval.

3. Photovoltaic installation according to any one of the preceding claims, the photovoltaic panels (15) being arranged in modules each comprising two parallel posts (31a, 31b) connected to each other by a first cross member (32) and by a second cross member (34) arranged orthogonally to the posts (31a, 31b) one, two, or more photovoltaic panels (21) arranged vertically in a space delimited by the posts (31a, 31b), the electronic energy management modules being housed in a free space (18) between two photovoltaic panels (21) and covered by a cover (37).

4. Photovoltaic installation according to the preceding claim, wherein the space (18) of a first photovoltaic module is aligned with a vertical axis (25) equidistant from the posts (31a, 31b) and allows to accommodate a second identical or compatible photovoltaic module forming a right angle with the first photovoltaic module.

5. Photovoltaic installation according to any one of the preceding claims, comprising an electrical circuit (65) between the poles (31a, 31b) allowing an adjacent photovoltaic module to be electrically connected.

6. Photovoltaic installation according to any one of the preceding claims, wherein the photovoltaic panels (21) are vertical and / or bifacial.

7. Photovoltaic installation according to any one of the preceding claims, configured to inject and measure a reverse current through the photovoltaic panel when the photovoltaic module is in darkness, and to activate the alarm signal when anomalies are observed in the measured reverse current.

8. Proximity or intrusion detection method, comprising measuring a photovoltaic current generated by a photovoltaic panel, comparing the measured photovoltaic current with an expected photovoltaic current, and generating an alarm based on the difference between the measured photovoltaic current and the expected photovoltaic current.

9. The method of the preceding claim, wherein the expected photovoltaic current is either a photovoltaic current generated from one or more reference photovoltaic panels under similar sunlight conditions, or an expected photovoltaic current obtained from a simulation or calculation.

10. The method of any one of claims 8 and 9, wherein the photovoltaic current is measured with a temporal resolution better than 5 minutes, preferably better than 30 seconds, more preferably than 1 second or less, and the alarm signal is generated when the difference between the measured photovoltaic current and the expected photovoltaic current increases within a predetermined time interval.

11. The method of any one of claims 8 to 10, comprising injecting and measuring a reverse current through the photovoltaic panel when the photovoltaic module is in darkness, and activating the alarm signal when anomalies in the measured reverse current are observed.

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