PROTECTION SYSTEM FOR PROTECTING A PHOTOVOLTAIC INSTALLATION AGAINST INCIDENT WIND AND METHOD FOR PROTECTING A PHOTOVOLTAIC INSTALLATION AGAINST DAMAGE CAUSED BY INCIDENT WIND

Abstract

A protection system protects against incident wind in a photovoltaic installation and a method protects a photovoltaic installation against damage caused by incident wind. The protection system for protecting a photovoltaic installation includes a plurality of parallel and spaced apart rows of solar trackers having a central shaft attached to supports by means of couplings and supporting photovoltaic panel; and at least one actuator device kinetically connected to the central shaft for modifying its angular position. At least one row comprises a deflecting barrier below the photovoltaic panels and between the supports, covering between 40% and 65% of the distance (D) existing between the central shaft and the ground, defining a passage (P) between the deflecting barrier and the central shaft for redirecting the incident wind.

Claims

1. A protection system for protecting a photovoltaic installation against incident wind, the system comprises: a plurality of parallel and spaced apart rows of solar trackers, defining multiple intermediate rows comprised between two end rows located at respective opposite ends of the photovoltaic installation, each solar tracker comprising a central shaft arranged at a predetermined distance (D) from the ground by multiple supports arranged at regular intervals, the central shaft being coupled to the supports through couplings which allow free rotation of the central shaft; multiple photovoltaic panels, interconnected and attached to said central shaft by a support structure, defining a solar collection plane; at least one actuator device controlled by a control unit, the actuator device being kinetically connected to said central shaft for modifying the angular position of the central shaft by the actuation of the actuator device, causing the solar collection plane of the photovoltaic panels attached to the central shaft to rotate an angle(A) with respect to the horizontal; and a deflecting barrier comprised on at least one row of the photovoltaic installation for redirecting the win incident of said solar tracker; wherein each deflecting barrier extends between the supports of the corresponding row and is arranged under the photovoltaic panels covering between 40% and 65% of the predetermined distance (D) existing between the central shaft and the ground, defining a free passage (P) between the deflecting barrier and the central shaft for channeling, and diverting, upwards, incident wind to a rear face of the photovoltaic panels, reducing the structural stresses experienced by said photovoltaic panels.

2. The protection system according to claim 1, wherein the deflecting barrier is located at least in the two end rows.

3. The protection system according to claim 2, wherein the deflecting barrier is also located in intermediate rows adjacent to each end row of the photovoltaic installation, defining two consecutive rows with a deflecting barrier.

4. The protection system according to claim 3, wherein the deflecting barrier is located in several of the intermediate rows of the photovoltaic installations, being arranged alternately with a predefined number of intermediate rows lacking a deflecting barrier.

5. The protection system according to claim 3, wherein the deflecting barrier is located in consecutive pairs of intermediate rows of the photovoltaic installation, said consecutive pairs of intermediate rows being arranged alternately with a predefined number of intermediate rows lacking a deflecting barrier.

6. The protection system according to claim 5, wherein the predefined number of intermediate rows lacking a deflecting barrier is selected to generate a separation of between 80 m and 120 m between the rows integrating the deflecting barriers.

7. The protection system according to claim 1, wherein each deflecting barrier is adjacent to or in contact with the ground.

8. The protection system according to claim 1, wherein the deflecting barrier is fixed to the supports and held by same.

9. The protection system according to claim 1, wherein the deflecting barrier is made of a material having a porosity equal to or less than 60%.

10. The protection system according to claim 1, wherein the deflecting barrier is selected from a group consisting of: sheet metal or perforated sheet metal; corrugated or ribbed sheet metal or perforated corrugated or ribbed sheet metal; fabric canvas or openwork fabric canvas; plastic canvas or openwork plastic canvas; wall or openwork wall; and earthen ridge.

11. The protection system according to claim 1, wherein the photovoltaic installation additionally comprises a determination device for determining the strength of the incident wind or a determination device for determining the strength and direction of the incident wind, said determination device being connected to the control units.

12. A method for protecting a photovoltaic installation against damage caused by incident wind by a protection system of claim 1, the method comprises the following steps: detecting incident wind with a speed greater than a predefined threshold; actuating the actuator device of the solar trackers of the rows provided with deflecting barriers, positioning the corresponding photovoltaic panels in a deflecting position in which they form an angle (A) between 30° and 60° with respect to the horizontal, diverting the incident wing upwards, away from the subsequent rows in the way of the incident wind; and actuating the actuator device of the solar trackers of the rows lacking deflecting barriers, positioning the corresponding photovoltaic panels in a standby position in the which they exhibit a minimum aerodynamic profile with respect to the incident wind; wherein the method further comprises: channeling part of the incident wind through the free passage (P) defined under the photovoltaic panel, between the deflecting barrier and the central shaft, and diverting said incident wind upwards to a rear face of the photovoltaic panels, reducing the structural stresses experience by the photovoltaic panels in the deflecting position.

13. The method according to claim 12, wherein the method further comprises: detecting the direction of the incident wind; and causing the actuation of all the solar trackers of the rows provided with deflecting barriers, with a front face of the corresponding photovoltaic panels being arranged windward according to the detected direction of the incident wind.

14. The method according to claim 12, wherein the method further comprises causing said actuation in solar trackers of pairs of adjacent rows provided with a deflecting barrier, with the corresponding solar collection planes being arranged with mirror inclination, such that incident wind transverse to the photovoltaic installation will, regardless of its direction, strike photovoltaic panels with a corresponding windward front face for each pair of adjacent rows provided with a deflecting barrier.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0077] The foregoing and other advantages and features will be better understood based on the following detailed description of an embodiment in reference to the attached drawings which must be interpreted in an illustrative and non-limiting manner, in which:

[0078] FIG. 1 shows a schematic cross-section view of the single-axis solar collectors of an end row and of an intermediate row adjacent to the end row, the solar panels being in a protective position, each single-axis solar collector showing a different embodiment of the deflecting barrier;

[0079] FIG. 2 shows the same as FIG. 1 but with each single-axis solar collector showing other different embodiments of the deflecting barrier;

[0080] FIG. 3 shows a schematic cross-section view of a photovoltaic installation in which incident wind of a significant strength originating from the west has been detected, and in which the photovoltaic panels of the rows provided with deflecting barriers have been positioned in the deflecting position with the front face windward and the rest in standby position;

[0081] FIG. 4 shows the same as FIG. 3, but in a photovoltaic installation in which incident wind of a significant strength originating from the east has been detected;

[0082] FIG. 5 shows a schematic cross-section view of a photovoltaic installation in which incident wind of a significant strength of unknown origin has been detected, and in which the photovoltaic panels of the rows provided with deflecting barriers have been positioned in the deflecting position and the rest in standby position, the rows provided with deflecting barriers being pairs of consecutive rows the photovoltaic panels of which are positioned with mirror inclinations with respect to a vertical plane, one row having the respective photovoltaic panels arranged with the front face thereof facing west and the subsequent row having the front face thereof facing east;

[0083] FIG. 6 shows an enlarged detailed view of two supports in the form of vertical props with their corresponding couplings and in which the rest of the single-axis solar collector has not been shown, including an openwork deflecting barrier fixed on said supports according to an embodiment;

[0084] FIG. 7 shows an enlarged detailed view of two supports in the form of trestles, one including a coupling and the other including an actuator device, and in which the rest of the single-axis solar collector has not been shown, including an openwork deflecting barrier fixed on said supports according to another embodiment.

DETAILED DESCRIPTION OF AN EMBODIMENT

[0085] The attached drawings show illustrative non-limiting embodiments of the present invention.

[0086] The present invention applies to photovoltaic installations 1 with single-axis solar trackers 20.

[0087] FIGS. 3, 4, and 5 show a cross-section of a photovoltaic installation 1 formed by six parallel rows of single-axis solar trackers 20 spaced apart equidistantly.

[0088] The first and last rows of the photovoltaic installation 1 are called end rows 12, whereas the remaining rows comprised between end rows 12 are called intermediate rows 11.

[0089] Each solar tracker 20, shown in more detail in FIGS. 1 and 2, consists of photovoltaic panels 23 the front face of which defines a solar collection plane. Said photovoltaic panels 23 are fixed on a support structure in the form of ribs extending symmetrically on both sides of a horizontal central shaft 21 having an approximate North-South orientation, the photovoltaic panels 23 therefore being centered and supported on said central shaft 21.

[0090] Supports 22 hold the central shaft 21 a specific distance D from the ground by couplings 25 which allow rotation of the central shaft 21 about its geometric axis, which allows inclining the solar collection plane an angle A eastward or westward.

[0091] Each solar tracker 20 includes at least one actuator device 24 which allows precisely modifying the angular position of the central shaft 21 and therefore the angle A of the photovoltaic panels 23 with respect to the horizontal.

[0092] According to the example shown in FIGS. 1 and 2, the actuator device 24 consists of a piston or linear motor connecting a point of a support 22 with a point of the support structure of the photovoltaic panels 23, such that by modifying the length thereof, the actuator device 24 modifies angle A.

[0093] According to another embodiment shown in FIG. 7, the actuator device consists of an electric motor connected to the central shaft 21 for determining its rotation. In this example, it is an electric motor concentric with the central shaft 21.

[0094] Other solutions of actuator devices 24 are also contemplated.

[0095] At least one control unit is connected to the actuator devices 24 of all the solar trackers 20 of the photovoltaic installation 1 for control thereof, where there may be one control unit for each solar tracker 20, for each row, or for the entire photovoltaic installation 1.

[0096] The control unit will be in charge of determining the angle A the solar collection planes form with respect to the horizontal at all times.

[0097] During normal operation, the control unit is in charge of orienting the photovoltaic panels 23 to maximize their electric production, following the position of the sun throughout the day.

[0098] In order to protect the photovoltaic installation 1 against damage caused by incident wind of a certain strength, the present invention furthermore proposes incorporating deflecting barriers 30 in the solar trackers 20 of some of the rows of the photovoltaic installation 1.

[0099] The deflecting barriers 30 are barriers located between the ground and the central shaft 21 of the corresponding solar tracker 20, between the supports 22 of the solar tracker 20. Said deflecting barrier 20 takes up between 40 and 65% of distance D existing between said ground and central shaft 21, leaving a free passage P between the upper end of the deflecting barrier 30 and the central shaft 21 and blocking the rest of said distance D.

[0100] In that sense, incident wind transverse to the row provided with the deflecting barrier 30 will hit against the deflecting barrier 30 below the photovoltaic panels 23 and be channeled through passage P.

[0101] It shall be considered that the deflecting barrier 30 is below the central shaft 21 when its upper end is located below the vertical projection of the central shaft 21 or up to 30 cm in front of or behind said vertical projection.

[0102] FIG. 1 shows two examples of the proposed deflecting barrier 30. In a first example, the deflecting barrier 30 consists of a ribbed vertical sheet with the ribbing thereof arranged horizontally, the sheet being located between and fixed to the supports 22 of the solar tracker 20.

[0103] In a second example, it is proposed for the deflecting barrier 30 to be a vertical mesh, a piece of cloth, or a canvas stretched out between and fixed to the supports 22. In both cases, the possibility of said deflecting barrier 30 being an openwork or perforated barrier is contemplated, achieving up to 60% wind permeability, which allows reducing the aerodynamic load said deflecting barrier 30 must withstand, and therefore allows reducing construction cost.

[0104] FIG. 2 shows other embodiments of the deflecting barrier 30. In one case, the deflecting barrier 30 formed by a ridge accumulated right below the central shaft 21 is shown, and in the other case a deflecting barrier 30 formed by a ribbed sheet is placed fixed in an inclined position on supports 22 in the form of a trestle.

[0105] In the present invention, when incident wind of a strength exceeding a predefined threshold is detected, for example through the connection thereof to an anemometer integrated in the photovoltaic installation 1 itself, or by the communication thereof with a weather station not related to the photovoltaic installation 1, it is proposed for the control unit to also be configured for locating the photovoltaic panels 23 of the solar collectors 20 associated with a deflecting barrier 30 in a deflecting position and the photovoltaic panels 23 of the solar collectors 20 lacking a deflecting barrier 30 in a standby position, as shown in FIGS. 3, 4, and 5.

[0106] In the deflecting position, the photovoltaic panels 23 are inclined to form an angle A between 30° and 60° with respect to the horizontal, preferably 45°.

[0107] Said angle allows the incident wind striking the front face of the photovoltaic panels 23 to be directed upwards, and the incident wind channeled through the passage P passes over the rear face of the photovoltaic panels 23, also being directed upwards while at the same time balancing out the pressure the incident wind exerts on the front face, reducing the dynamic loads which the photovoltaic panels 23 withstand and reducing turbulences leeward of the panels.

[0108] As a result of this configuration, the incident wind is diverted upwardly, preventing the incident wind from affecting successive rows of the photovoltaic installation 1.

[0109] In the standby position, the photovoltaic panels 23 are positioned at an angle A which minimizes their aerodynamic profile with respect to the incident wind, i.e., reduces the surface exposed to the incident wind. Typically, this angle A will be 0°, the photovoltaic panels 23 being horizontal.

[0110] When not only the strength, but also the direction of the incident wind is known, all the photovoltaic panels 23 associated with a deflecting barrier 30 will be inclined, exposing their front face windward, as shown in FIGS. 3 and 4.

[0111] When the direction of the wind is unknown, the photovoltaic panels 23 of two successive rows, both provided with deflecting barriers 30, will thus be placed in mirror deflecting position, i.e., both rows with the inclination of the respective photovoltaic panels 23 with a symmetrical inclination with respect to a vertical plane, with the rear faces of the photovoltaic panels 23 of both rows partially facing one another.

[0112] This configuration shown in FIGS. 1, 2, and 5 allows the incident wind to be diverted regardless of its direction, protecting the subsequent rows.

[0113] Preferably, the deflecting barriers 30 will be located in the end rows 12 most exposed to the incident wind, and optionally also in some of the intermediate rows 11, locating at least one deflecting barrier 30 every 80 and 120 meters.

[0114] Although this constitutes the preferred embodiment, it is also contemplated for the end rows 12 to not have any deflecting barrier 30, with the barriers located only in intermediate rows 11.

[0115] In the examples shown in FIGS. 3, 4, and 5, deflecting barriers 30 have only been included in the end rows 12 or in the intermediate rows 11 immediately adjacent to the end rows 12, however, in a photovoltaic installation with a larger number of intermediate rows 11 deflecting barriers 30 may also be additionally included in some intermediate rows 11, being arranged alternately with other intermediate rows 11 lacking deflecting barriers 30.

[0116] Ideally, deflecting barriers 30 will be located about every 100 meters, which is the distance considered as being protected by a deflecting barrier 30, i.e., the rows provided with deflecting barriers 30 will be spaced 80 m and 120 m apart, and as many intermediate rows 11 lacking deflecting barriers 30 that can fit therein will be included between them.

[0117] Likewise, pairs of intermediate rows 11 with deflecting barriers 30 which will be placed with the mirror arrangement shown in FIGS. 1 and 2 when incident wind is detected can be included about every 100 m.

[0118] It will be understood that the different parts making up the invention described in an embodiment can be freely combined with parts described in other different embodiments even though said combination has not been explicitly described, provided that the combination does not entail any drawback.