A flexible photovoltaic support cable sag and cable force detection device and method

Abstract

The application provides a flexible photovoltaic support cable sag and cable force detection device and method, relates to the photovoltaic technical field, and the method comprises the following steps: measuring the sag of the flexible photovoltaic support cable, combining the technical parameters of the flexible photovoltaic support, and constructing a cable calculation equation through a mechanical modeling method to solve the cable force of the cable; the device comprises a measuring part and a positioning part, the measuring part comprises a vertical rod one, the top end of the vertical rod one is provided with a laser range finder, the laser range finder is rotationally connected with the vertical rod one, one side of the laser range finder is provided with an angle measuring half circle ruler, a positioning scale one is arranged on the side, away from the laser range finder, of the angle measuring half circle ruler, and a bubble level is further arranged on the vertical rod one; the positioning part comprises a vertical rod two, the top end of the vertical rod two is provided with a reflecting plate, the center of the reflecting plate is provided with a laser positioning ring, a laser aiming ring is concentrically arranged in the laser positioning ring, a positioning scale two is arranged on one side of the reflecting plate, and a bubble level is arranged on the vertical rod two. The device has the characteristics of simple measurement operation.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photovoltaic technology, in particular to a flexible photovoltaic support cable sag and cable force detection device and method. BACKGROUND

[0002] Under the background of double carbon target, the photovoltaic industry is developing rapidly. With the expansion of photovoltaic installation scale, some conditions in mountainous areas, deserts, plains and fish ponds have been gradually developed, and the available land resources are decreasing. Flexible photovoltaic support can realize the important technical direction of land use conflict by tensioning the prestressed steel strand between two supports, and the photovoltaic panel is fixed on the steel strand by buckle. As a new type of photovoltaic support, flexible photovoltaic support has obvious technical advantages and has been widely used in photovoltaic projects in recent years. However, there is a lack of flexible photovoltaic support construction quality detection method and engineering quality acceptance equipment and facilities in engineering practice.

[0003] Flexible photovoltaic support is a cable structure photovoltaic support that applies a large prestress to the steel strand to greatly improve the stiffness of the steel strand and make it have the ability to support the weight of photovoltaic components and wind load. The prestress applied by the cable directly determines the stiffness and carrying capacity of the cable, and thus affects the safety of the structure and the construction quality of the project; the sag of the steel strand under the action of prestress and the weight of the component will cause the change of the orientation of the photovoltaic component, which will reduce the power generation efficiency of the component, so the cable sag needs to be controlled in engineering practice. However, in actual engineering construction, the prestress of the continuous multi-span flexible photovoltaic support structure is generally tensioned by using a through-hole jack at both ends of the steel strand, and the prestress value is read from the oil pressure gauge of the jack. However, due to the friction loss of the steel strand at the middle column, there is a certain difference in the prestress applied by each span of the continuous cable; in addition, due to the influence of the technical level and responsibility of the construction personnel, it is difficult to avoid the problem of insufficient prestress applied by some cables in large-scale cable tensioning. After the completion of the photovoltaic project, the steel strand cable may relax due to the influence of earthquakes, snow disasters or other sudden disasters during the long-term operation of the flexible photovoltaic support structure, and the cable force and sag of the steel strand need to be measured to evaluate the safety of the structure.

[0004] Therefore, a cable force and sag measuring tool is urgently needed for flexible photovoltaic support projects to detect the cable force and sag of the steel strand after installation and tensioning or after being relaxed due to disasters, so as to check whether the cable force and sag of the flexible photovoltaic support meet the design requirements, provide measured data for project acceptance and safety evaluation after disasters, and ensure the quality and safety of the project.

[0005] The traditional pressure sensor measurement cable force technology is relatively mature, but it needs to be connected in series with the cable, needs to be pre-buried in the cable before installation and tensioning, and is not suitable for engineering project quality inspection. After searching, no cable force and sag detection device and method applied to flexible photovoltaic support was found. The invention patent "Cable force measurement method based on frequency optimization frequency method" (CN117647347B) relies on the vibration frequency of the cable to measure the cable force, which is suitable for cable force measurement of unloaded empty cable of cable span, but this technology cannot be applied to the cable full of photovoltaic components load in the flexible photovoltaic support span. The invention patent "Nondestructive in-situ measurement device and method" (CN109596257B) relies on the principle of magnetic flux to measure the cable force, but the closed-loop magnetic flux cable force measuring instrument needs to be pre-inserted into the sensor before the cable is tensioned, and cannot be disassembled after installation, which is not suitable for engineering inspection. The open-loop magnetic flux cable force measuring instrument has a magnetic leakage phenomenon, and the measurement result error is large, which is also not suitable for engineering application. The present application measures the shape of the cable, and inversely calculates the cable force by mechanical principle. The detection tool used is a portable device, which does not need to be installed and disassembled on the structure, and solves the problems of convenient measurement and spot inspection of flexible photovoltaic support cable force and sag. SUMMARY

[0006] The present application provides a flexible photovoltaic support cable sag and cable force detection device and method, which aims to at least solve the technical problems existing in the prior art mentioned in the background art.

[0007] The present application provides the following technical solutions to achieve the above-mentioned purposes:

[0008] A device for detecting the sag and cable force of a flexible photovoltaic support cable, comprising a measuring part and a positioning part, the measuring part comprising a vertical rod one, the top end of the vertical rod one being provided with a range finder head, the range finder head comprising a motor, a laser range finder being provided on the rotating shaft of the motor, a protractor half-circle scale being provided on one side of the laser range finder, the center of the protractor half-circle scale corresponding to the rotating shaft, a positioning scale one being provided on the side of the protractor half-circle scale away from the laser range finder, a bubble level being further provided on the vertical rod one; the positioning part comprising a vertical rod two, the top end of the vertical rod two being provided with a reflector plate, the center of the reflector plate being provided with a laser positioning ring, a laser aiming ring being concentrically provided in the laser positioning ring, a positioning scale two being provided on one side of the reflector plate, a bubble level being provided on the vertical rod two; the laser distance between the positioning scale one and the laser range finder being equal to the distance between the positioning scale two and the laser aiming ring.

[0009] Further, the vertical rod one and the vertical rod two are telescopic rods, and a scale is provided on the rod, the vertical rod one and the vertical rod two comprising a lower section pipe rod member, the lower section pipe rod member being sleeved with an upper section pipe rod member, the lower section pipe rod member being provided with a fastening bolt.

[0010] Further, a telescope is provided on the vertical rod one.

[0011] Further, the vertical rod one is provided with a controller, the controller is electrically connected with the laser range finder and the motor; the controller is installed on the fuselage support, the fuselage support is connected with the vertical rod one through the spring clamp, and a calculation program is preset in the controller.

[0012] Further, the one end of the light-reflecting plate connected with the vertical rod two is provided with a light-reflecting plate stiffened thick rim, the middle part of the light-reflecting plate stiffened thick rim is provided with a connecting bolt hole, and the light-reflecting plate stiffened thick rim is connected with the vertical rod two through the connecting bolt hole.

[0013] Further, the contact surface of the spring clamp and the vertical rod two is provided with a rubber gasket.

[0014] Further, the method for detecting the sag and cable force of the flexible photovoltaic support cable, comprising the following steps that: measuring the sag of the flexible photovoltaic support cable, combining the technical parameters of the flexible photovoltaic support, and constructing a cable calculation equation through a mechanical modeling method to solve the cable force of the cable;

[0015] The method for measuring the sag comprises the following steps that: connecting two end points of the flexible photovoltaic support to form a straight line, keeping the angle of the straight line unchanged, adjusting the height of the straight line to be tangent to the bottom of the cable, the point where the straight line is tangent to the cable is the position of the sag, and the height of the straight line is the sag;

[0016] The establishment process of the cable calculation equation comprises the following steps that:

[0017] Based on the gravity of the cable itself, considering that the photovoltaic panels are uniformly and interval laid on the cable, the gravity of the cable itself and the weight of the photovoltaic panels are equivalent to the uniform linear load through the mechanical calculation principle, and the equation is established as follows:

[0018] Wherein f is the sag, F is the cable force, L1 is the chord length of the cable, α is the included angle between L1 and the horizontal plane, and q is the uniform linear load.

[0019] Further, the technical parameters comprise the length, specification of the cable, the model of the photovoltaic panel and the number of the photovoltaic panels.

[0020] Beneficial effects

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] The present application measures the chord length and the inclination angle of the cable through the laser ranging principle at the two end heads of the flexible photovoltaic support cable in one span, obtains the cable sag through the geometric principle conversion, and obtains the cable force through the mechanical principle conversion;

[0023] The present application provides a kind of flexible photovoltaic support cable sag and cable force detection device and method, which provides a kind of measurement means and method for project quality inspection and project post-disaster quality evaluation;

[0024] The present application can measure the cable force without embedding sensors in the cable in advance, without pre-installation process, without installation on the structure, and without influence on the structure during detection operation;

[0025] The present application uses optical principle and mechanical principle for detection, without use of precise sensors and precise electronic instruments, and the detection result is not affected by external environment, and the error of the detection result is small;

[0026] The device of the present application is all small components, convenient to carry and install and disassemble, simple to measure and convenient to operate, and is suitable for various complex topographies and application scenarios such as mountain, fish pond, building photovoltaic, etc.

[0027] The present application provides a method for obtaining cable force and sag without erecting detection instruments in the middle of the structure, and only expanding detection work at the stand columns at both ends of the structure, which is suitable for photovoltaic power stations in complex terrain scenarios such as crossing valleys and crossing deep water fish ponds, and is difficult for ground detection personnel in the middle of the flexible photovoltaic support to reach and inconvenient to erect measurement and positioning parts. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings described below relate to only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor under the premise of the drawings.

[0029] Figure 1 It is a structural schematic diagram of the measurement part of the present application;

[0030] Figure 2 It is a structural schematic diagram of the positioning part of the present application;

[0031] Figure 3 It is a structural schematic diagram of the range finder head of the present application;

[0032] Figure 4 It is Figure 3 A-A sectional view;

[0033] Figure 5 It is a structural schematic diagram of the body support and spring clamp;

[0034] Figure 6 It is a schematic diagram of the controller of the present application;

[0035] Figure 7 It is a structural schematic diagram of the reflector plate of the present application;

[0036] Figure 8 It is Figure 7B-B cross-sectional view;

[0037] Figure 9 Schematic diagram of method for using the present application;

[0038] Figure 10 Schematic diagram of method for using the present application;

[0039] Figure 11 Calculation principle diagram of method for using the present application;

[0040] Figure 12 Calculation principle diagram of method for using the present application.

[0041] Reference signs: 1 - range finder head; 1.1 - laser range finder; 1.2 - laser; 1.3 - angle measuring semicircle scale; 1.4 - motor; 1.5 - rotating shaft; 1.6 - bolt hole; 1.7 - positioning scale 1; 2 - vertical rod; 2.1 - vertical rod 1; 2.2 - vertical rod 2; 3 - controller; 3.1 controller display screen; 3.2 - control key; 3.3 - parameter key; 3.4 - body support; 3.5 - spring clamp; 3.6 - rubber gasket; 4 - bubble level; 5 - telescope; 6 - reflector; 6.1 - laser positioning ring; 6.2 - laser aiming ring; 6.3 - positioning scale 2; 6.4 - reflector reinforced thick rim; 6.5 - connecting bolt hole; 7 - cable; 8 - anchoring cable; 9 - supporting column. DETAILED DESCRIPTION

[0042] In order to make the personnel in the art better understand the present application scheme, the technical solutions in the embodiments of the present application will be described clearly and completely below by combining the drawings in the embodiments of the present application.

[0043] It should be noted that in the present application: the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices; the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "transverse", "longitudinal" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and these terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation; the terms "first", "second" and the like are used to distinguish similar objects, and do not necessarily describe a specific order or sequence; the terms "mounting", "setting", "provided with", "connecting", "connected", "sleeved" and the like should be interpreted broadly; for example, it can be fixedly connected, detachably connected, or integrally constructed; it can be mechanically connected, or electrically connected; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication between two devices, elements or components. In addition, in addition to indicating the orientation or positional relationship, some terms can also be used to indicate other meanings, for example, the term "upper" may also be used to indicate a certain dependent relationship or connection relationship in some cases. For those skilled in the art, the specific meaning of these terms in the present application can be understood according to the specific circumstances.

[0044] Embodiment 1. A device for detecting sag and cable force of a flexible photovoltaic support cable, the structure is referred to Figure 1, including a measuring part and a positioning part, the measuring part includes a vertical rod one 2.1, the top end of the vertical rod one 2.1 is provided with a range finder head 1, the range finder head 1 includes a motor 1.4, the rotating shaft 1.5 of the motor 1.4 is provided with a laser range finder 1.1, one side of the laser range finder 1.1 is provided with an angle measuring half circle ruler 1.3, the center of the angle measuring half circle ruler 1.3 is correspondingly provided with the rotating shaft 1.5, the side, away from the laser range finder 1.1, of the angle measuring half circle ruler 1.3 is provided with a positioning scale one 6.3, the vertical rod one 2.1 is further provided with a bubble level 4; the positioning part includes a vertical rod two 2.2, the top end of the vertical rod two 2.2 is provided with a reflecting plate 6, the center of the reflecting plate 6 is provided with a laser positioning ring 6.1, the laser positioning ring 6.1 is concentrically provided with a laser aiming ring 6.2 in the reflecting plate 6, the side of the reflecting plate 6 is provided with a positioning scale two 6.3, the vertical rod two 2.2 is provided with a bubble level 4; the distance between the positioning scale one 6.3 and the laser 1.2 of the laser range finder 1.1 is equal to the distance between the positioning scale two 6.3 and the laser aiming ring 6.2. The positioning scale one 6.3 and the positioning scale two 6.3 are in a pointer type structure, which is convenient for accurate positioning; the center of the reflecting plate 6 is provided with the laser positioning ring 6.1, which is convenient for ensuring the accuracy of the laser range finder 1.1 during the measuring process; the distance between the positioning scale one 6.3 and the laser of the laser range finder 1.1 is equal to the distance between the positioning scale two 6.3 and the laser aiming ring 6.2, which ensures that the laser 1.2 of the range finder falls in the laser aiming ring of the reflecting plate 6.

[0045] The vertical rod one 2.1 and the vertical rod two 2.2 are telescopic rods, the rods are provided with scale rulers, the vertical rod one 2.1 and the vertical rod two 2.2 include a lower section pipe rod member, the lower section pipe rod member is sleeved with an upper section pipe rod member, and the lower section pipe rod member is provided with a fastening bolt. The telescopic rods are achieved by adopting the sleeving form of the lower section pipe rod member and the upper section pipe rod member, and the fixing of the telescopic rods is achieved by the fastening bolt; the scale rulers are provided on the vertical rod one 2.1 and the vertical rod two 2.2, which is convenient for directly reading the height of the laser range finder 1.1 during the measuring process.

[0046] The vertical rod one 2.1 is provided with a telescope 5. The telescope 5 is provided, which is convenient for observing from the measuring part to the positioning part during the measuring process, ensures that the laser 1.2 of the laser range finder 1.1 falls in the laser positioning ring 6.1 of the reflecting plate 6, and guarantees the accuracy of the measuring effect.

[0047] The end, connected with the vertical rod two 2.2, of the reflecting plate 6 is provided with a reflecting plate stiffened thick rim 6.4, the middle part of the reflecting plate stiffened thick rim 6.4 is provided with a connecting bolt hole 6.5, and the reflecting plate stiffened thick rim 6.4 is connected with the vertical rod two 2.2 through the connecting bolt hole 6.5. The reflecting plate stiffened thick rim 6.4 is provided on the reflecting plate 6, which improves the connecting strength between the reflecting plate 6 and the vertical rod two 2.2, and guarantees the use safety of the positioning part.

[0048] Example 2: The structure of this example is the same as that of Example 1, except that a controller 3 is installed on the first upright 2.1. The controller 3 is electrically connected to the laser rangefinder 1.1 and the motor 1.4. The controller 3 is mounted on the body support 3.4, which is connected to the first upright 2.1 via a spring clip 3.5. The controller 3 contains a calculation program. A rubber gasket 3.6 is provided on the contact surface between the spring clip 3.5 and the second upright 2.2. The calculation program includes: pre-setting the cross-sectional area of ​​the cable strand specifications and diameter and the standard weight of commonly used photovoltaic modules in the controller 3; treating the weight of the cable itself and the photovoltaic panel installation as uniform linear loads and recording them as q according to the principles of mechanical calculation; establishing a uniform linear load calculation equation and solving for q based on the photovoltaic panel installation conditions, specifications and selected cable strand specifications at the engineering site; substituting the solved q into the cable force equation to obtain the cable force F; during measurement, only the cable and photovoltaic module specifications are selected, without needing to input the cross-sectional area and component weight to establish the uniform linear load q, thus simplifying the measurement procedure; and preventing the controller 3 from sliding by setting a rubber pad 3.6 on the contact surface between the spring clip 3.5 and the upright 2.2.

[0049] The method of using this invention is as follows:

[0050] Method 1: When the flexible photovoltaic support is installed in an area accessible to humans, the flexible photovoltaic support includes a cable 7, with both ends of the cable 7 installed at the top of the support column 9, and an anchoring cable 8 is provided on the side of the support column 9 away from the cable 7.

[0051] 1) Install measuring components

[0052] During the measurement operation, the measuring components are assembled on the ground and placed at one end of the cable 7. The upright pole 2.1 is raised so that the positioning scale 1.7 of the distance measuring head reaches the height of the end of the load-bearing cable 7, and the arrow of the positioning scale 1.7 is close to the center of the side of the load-bearing cable 7. The fixing bolts are then tightened.

[0053] 2) Install positioning unit

[0054] During the measurement operation, assemble the positioning unit on the ground and place it at the other end of the load-bearing cable 7. Raise the second upright 2.2 so that the reflector positioning scale 6.3 reaches the height of the end of the load-bearing cable 7, with the arrow of the positioning scale close to the center of the side of the load-bearing cable 7, and tighten the fixing bolts. Adjust the bubble of the bubble level 4 on the second upright 2.2 to the center to ensure that the second upright 2.2 is vertical;

[0055] 3) Adjusting the measuring components

[0056] Search the position of the reflector through the telescope 5, adjust the vertical rod 1 2.1, make sure the telescope sight can fall within the laser positioning ring 6.1 of the reflector 6. Adjust the bubble of the bubble level 4 on the vertical rod 1 2.1 to the center, make sure the vertical rod 1 2.1 is vertical;

[0057] 4) Measure the chord length L1 of the cable span

[0058] Turn on the laser rangefinder laser 1.2 through the controller 3, use the telescope 5 to observe the reflector, adjust the angle of the laser rangefinder laser 1.2 through the controller 3, make sure the laser 1.2 falls within the reflector sight ring 6.2, click the controller 3 keyboard button 3.3 to trigger the measurement, measure the chord length L1 of the cable, read the angle α of the laser 1.2 from the angle measuring semicircle 1.3;

[0059] 5) Search the position of the cable span

[0060] Keep the position of the measurement part unchanged, keep the angle α of the laser 1.2 unchanged, move the reflector to the position of the cable span, adjust the vertical rod 2 2.2 of the positioning part to make the laser 1.2 fall within the positioning ring 6.1 of the reflector, click the controller 3 keyboard button 3.3 again to trigger the measurement, measure the distance L2. Adjust the position of the measurement part multiple times, make the measured L2 within the following interval, consider that the position of the positioning part at this time is the position of the cable span. The L2 within the following interval can ensure that the measurement error is ±1%, which meets the general project detection requirements;

[0061]

[0062] 6) Measure the chord length L3 from the cable end to the position of the cable span

[0063] Keep the position of the vertical rod 2 2.2 of the positioning part unchanged, lower the vertical rod 2 2.2, align the positioning scale 2 6.3 with the position of the cable span, make the arrow of the positioning scale 2 6.3 close to the center of the side surface of the cable 7, fix the fastening bolt. Adjust the angle of the laser rangefinder laser through the controller 3, make the laser point fall within the laser sight ring 6.2, click the controller 3 keyboard button 3.3 to trigger the measurement, measure the chord length L3 from the cable end to the position of the cable span, read the angle β of the laser from the angle measuring semicircle 1.3;

[0064] 7) Input the load of the cable

[0065] Input the parameters of the load of the cable through the keyboard button 3.3 of the controller 3, input the cross-sectional area A of the cable, the weight G of a single photovoltaic panel, the number N of photovoltaic panels arranged in a cable span, and the number m of cables directly supported by the assembly;

[0066] 8) Output the results of the sag and cable force detection

[0067] The controller 3 is provided with a calculation program, according to the input load parameters and measured data, the cable force and sag are calculated and displayed on the controller display screen 3.1, the calculation program is as follows:

[0068]

[0069] Method two is used when the flexible photovoltaic support is erected in an area that is not accessible by human, such as rivers, cliffs and gullies, and when the height difference between the two ends of the flexible photovoltaic support is too large (the height difference is greater than 10% of the height of the support), the sag of the flexible photovoltaic support does not occur at the midspan position,

[0070] 1) Install the measuring component

[0071] During the measurement operation, the measuring component is assembled on the ground and placed at one end of the bearing cable 7. Raise the vertical rod 2.1 so that the ranging machine head positioning scale 1.7 reaches the height of the end of the bearing cable 7, the positioning scale arrow is close to the center of the side of the bearing cable 7, and the fixing bolt is fixed.

[0072] 2) Install the positioning component

[0073] During the measurement operation, the reflective component is assembled on the ground and placed at the other end of the bearing cable 7. Raise the vertical rod 2.2 so that the reflective plate positioning scale 6.3 reaches the height of the end of the bearing cable 7, the positioning scale 6.3 arrow is close to the center of the side of the bearing cable 7, and the fixing bolt is fixed. Adjust the bubble of the bubble level 4 of the vertical rod 2.2 to the center to ensure that the vertical rod 2.2 is vertical.

[0074] 3) Debug the measuring component

[0075] Search for the position of the reflective plate 6 through the telescope 5, adjust the orientation of the vertical rod 1 2.1 to ensure that the field of view of the telescope 5 can fall within the laser positioning ring 6.1. Adjust the bubble of the bubble level 4 on the vertical rod 1 2.1 to the center to ensure that the vertical rod 1 2.1 is vertical.

[0076] 4) Read the height h1 of the measuring component laser instrument through the scale on the vertical rod 1 2.1

[0077] 5) Measure the cable span chord length L1

[0078] Turn on the laser 1.2 of the laser range finder through the controller 3, use the telescope 5 to observe the reflective plate, and adjust the angle of the laser 1.2 emitted by the laser range finder 1.1 through the controller 3 to make the laser 1.2 fall within the reflective plate aiming ring 6.2, click the keyboard button 3.3 of the controller 3 to trigger the measurement, and measure the cable chord length L1 and the laser emission angle a.

[0079] 6) Move, reassemble, and debug the measuring component

[0080] Keep the laser emitter angle α unchanged, move the measuring part to make the laser range finder 1.1 directly below the end of the cable, re-install the measuring part, and adjust the hand-held vertical rod 2.1 to the lowest; adjust the orientation of the vertical rod 1.1, make sure the telescope 5 can be aimed at the cable, adjust the bubble level 4 on the vertical rod 1.1 to the center, and make sure the hand-held vertical rod 1.1 is vertical.

[0081] 7) Search for the sag position of the cable, read the height h2 of the measuring part laser

[0082] Keep the laser emitter angle α unchanged, slowly adjust the vertical rod 1.1, and use the telescope 5 to observe the laser point; when the laser point is just at the lower end of the cable (the laser 1.2 is tangent to the cable), fix the vertical rod 1.1, and read the height h2 of the measuring part laser through the scale on the vertical rod 1.1.

[0083] 8) Input the cable load

[0084] Input the cable load parameters through the keyboard 3.3 of the controller 3, input the cross-sectional area As of the cable, the weight G of a single photovoltaic panel, the number N of photovoltaic panels arranged in a span, and the number m of cables directly supported by the assembly.

[0085] 9) Output the sag and cable force detection results

[0086] The controller 3 is packaged with a calculation program, which calculates the cable force and sag according to the input load parameters and measured data and displays them on the display screen 3.1 of the controller; the calculation program is as follows:

[0087]

[0088] f = h1 - h2

[0089]

[0090] The application has been used in a mountain photovoltaic project and a deep water fish pond fish-light complementary photovoltaic project, the flexible photovoltaic support of the mountain photovoltaic project adopts a two-cable structure, after the component is installed, it is found by visual inspection that the sag of the flexible photovoltaic support of a part of the project is relatively large. The owner entrusts the application to detect the cable force and the sag of the flexible photovoltaic support of the mountain photovoltaic project, and the detection result is used as the basis for the project acceptance. The flexible photovoltaic support of the project is arranged everywhere in the mountains, and the detection work is difficult, the application plays the portability of the device and the convenience of the operation in the detection work, and the detection work of all the support cables of the project is completed in a short time, according to the cable internal force detection data, it is found that the sag and the cable force of 43% of the cables of the project do not meet the design requirements. After the owner receives the detection result, the owner requires the construction unit to reinforce and tension, and finally the quality problem of the project is eliminated. The detection process of one of the cables of the project is as follows:

[0091] According to the design document, the cable adopts 1860Mpa, the diameter is 15.2mm steel strand, the component adopts 550Wp, DAS-DH144PA type component of a certain factory, and 14 blocks of components are arranged per span. The cross-sectional nominal cross-sectional area of the steel strand is 140mm2 which is read out from the instrument database automatically by selecting the steel strand of the specification by the controller; the weight of the component is 32.7kg which is read out from the instrument database automatically by selecting the photovoltaic component by the operation instrument; after the detection work of one of the cables of the project is carried out by the detection method one, it is found that L1=17650mm, α=28.3°; L3=6550mm, β=27.35°.

[0092] The sag of the cable in the middle of the span is 201.4mm, and the cable force is 38.938kN which are obtained by the automatic calculation of the encapsulation program in the controller, and the program calculation process is as follows:

[0093]

[0094] q=0.15658(N / mm)

[0095]

[0096] f=201.4(mm)

[0097]

[0098] F=38938(N)=38.938(kN);

[0099] Wherein q is the conversion uniform linear load, ρ is the density of the cable material and is taken as 7850kg / m3, g is the gravity acceleration and is taken as 9.8N / kg, f is the sag, and F is the cable force

[0100] The design document requires that the sag of the cable in the middle of the span should be f ≤ L1 / 150, i.e. f ≤ 117.7 mm, and the cable force F should reach 67 kN. After the detection according to the application, the sag of the cable in the middle of the span is f = 201.4 mm, and the cable force F = 38.938 kN. The construction of the flexible photovoltaic support cable of the project does not meet the design requirements, and the cable tensioning construction has quality problems, and the acceptance is unqualified! After the detection, the project owner requires the construction unit to tension the cable again. When the cable is tensioned again, the cable anchor is removed, and the cable force acts on the through-hole jack. The oil pressure table of the jack shows that the pressure is relatively close to the cable force value of 38.3 kN, which is close to the cable force measured by the application, proving the accuracy of the cable force measurement of the application. After the tensioning, the sag of the flexible photovoltaic support cable in the middle of the span is effectively reduced, and the quality of the project is effectively controlled.

[0101] The flexible photovoltaic support of the deep water fish pond fish-light complementary photovoltaic project adopts a two-cable structure. After being affected by several typhoons during the service period of the project structure, the sag of a part of the flexible photovoltaic support cable in the middle of the span is increased. The flexible support is erected above the deep and wide fish pond, and it is difficult for the measurement personnel to reach the middle of the span of the cable, and it is difficult to detect the sag of the cable. According to the entrustment of the owner, the cable force and sag of the mountain photovoltaic project are detected by the application, and the detection results are used as the basis for post-disaster evaluation of the project. The flexible photovoltaic support of the project is distributed in the irregular deep water fish pond in the field, and it is difficult for the detection personnel to reach the measurement work in the fish pond. The detection work is difficult. The application plays the portability of the device and the convenience of the operation, and completes the detection work of all support cables of the project in a short time. According to the detection data, 20% of the cable sag and cable force of the project do not meet the original design structure service internal force requirement. After the detection results are fed back to the owner, the owner tensioned the cable with increased sag that does not meet the original design requirement, and finally eliminated the quality problems of the project.

[0102] The detection process of one span cable of the project is as follows:

[0103] According to the original design document, the cable of the project adopts 1860Mpa, 17.8mm diameter steel strand, and the assembly adopts 615Wp, JAM72D42615 / LB type assembly of a certain manufacturer, and 28 assemblies are arranged per span. The cross-sectional nominal cross-sectional area of the steel strand is 191mm2, which is read out from the instrument database by selecting the steel strand with the controller; the weight of the photovoltaic assembly is 34.6kg, which is read out from the instrument database by selecting the photovoltaic assembly with the controller.

[0104] After the detection of one span cable of the project by the above-mentioned detection method two, L1 = 33420mm, α = 11.2°; h1 = 5200mm, h2 = 4890mm.

[0105] The verticality of the cable in the middle of the span is 201.4 mm and the cable force is 38.938 kN, which are automatically calculated by the calculation program in the manipulator, and the program calculation process is as follows:

[0106]

[0107] q = 0.15978 (N / mm)

[0108] f = h1-h2

[0109] f = 5200-4890

[0110] f = 310 (mm)

[0111]

[0112] F = 74779.97 (N) = 74.78 (kN);

[0113] The design document requires that the sag of the cable in the middle of the span should be f≤L1 / 150, that is, f≤222.8 mm, and the cable force F should reach 104 kN. After the detection of the present application, the sag of the cable in the middle of the span is f = 310 mm, and the cable force F = 74.78 kN. After several typhoons, the cable force and the sag of the flexible photovoltaic support do not meet the design requirements. The post-disaster quality evaluation of the project is that the flexible support of the project, the cable and the sag exceed the design normal use state limit value, and do not have the ability to continue to serve! It is suggested that the owner take reinforcement measures to ensure that the structure is in the design normal use state and has the ability to serve! When the owner reinforces and tension the cable later, it is found that the cable anchorage end has slip traces, which confirms that the cable slip under the typhoon load leads to the relaxation of the cable internal force and the increase of the sag. When reinforcing and tensioning, the cable anchor is removed, and the cable force acts on the through-hole jack. The oil pressure table of the jack shows that the relative cable force value is 73.6 kN, which is close to the cable force measured by the present application, proving the accuracy of the cable force measurement of the present application. After reinforcing and tensioning, the sag of the cable in the middle of the flexible photovoltaic support is effectively reduced, the quality of the project is effectively improved, and the safety of the structure is effectively guaranteed.

[0114] Obviously, the above-described embodiments are only a part of the present application, not all. The above embodiments are not intended to limit the present application. For those skilled in the art, the present application can have various changes and variations. Any combination, modification, equivalent replacement, improvement and other embodiments made by those skilled in the art within the spirit and principle of the present application should be within the protection scope of the present application.

Claims

1. A device for detecting the sag and tension of cables in flexible photovoltaic support structures, characterized in that: The system includes a measuring unit and a positioning unit. The measuring unit includes a first pole with a distance measuring head at its top. The distance measuring head includes a motor, and a laser rangefinder is mounted on the motor's shaft. A semicircular protractor is mounted on one side of the laser rangefinder, with its center aligned with the shaft. A positioning scale is mounted on the side of the semicircular protractor away from the laser rangefinder. A bubble level is also mounted on the first pole. The positioning unit includes a second pole with a reflector at its top. A laser positioning ring is positioned at the center of the reflector, and a laser sight ring is concentrically positioned within the laser positioning ring. A positioning scale is mounted on one side of the reflector, and a bubble level is mounted on the second pole. The laser distance between the positioning scale and the laser rangefinder is equal to the distance between the positioning scale and the laser sight ring. The first and second uprights are telescopic poles, and scales are provided on the poles. The first and second uprights include a lower section tube member, an upper section tube member is sleeved inside the lower section tube member, and fastening bolts are provided on the lower section tube member. A telescope is installed on one of the uprights; A controller is installed on the first upright post, and the controller is electrically connected to the laser rangefinder and the motor. The controller is mounted on the machine body support, which is connected to the first upright post via a spring clip. The controller contains a calculation program, which includes: pre-setting the cross-sectional area of ​​the diameter of the cable strand and the standard weight of commonly used photovoltaic modules in the controller; and, based on mechanical calculation principles, treating the weight of the cable itself and the photovoltaic panel installation as uniform linear loads and recording them as... Based on the solution Substituting into the cable force equation, we obtain the cable force. The equation is established as follows: Where f is the sag and F is the cable force. Let the chord length of the cable be , for The angle with the horizontal plane, For uniform linear loads; connect the two ends of the flexible photovoltaic support to form a straight line, keep the angle of the straight line unchanged, adjust the height of the straight line to be tangent to the bottom of the cable, the point where the straight line is tangent to the cable is the position of the sag, and the height of the straight line is the sag.

2. The device for detecting sag and tension of flexible photovoltaic support cables according to claim 1, characterized in that: The reflector is provided with a stiffening flange at one end where it is connected to the second pole. A connecting bolt hole is provided in the middle of the stiffening flange, and the stiffening flange is connected to the second pole through the connecting bolt hole.

3. The device for detecting sag and tension of flexible photovoltaic support cables according to claim 1, characterized in that: A rubber pad is provided on the contact surface between the spring clip and the upright.

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