Mountain flexible photovoltaic support cable force monitoring assembly, monitoring system and use method

Abstract

The invention relates to the technical field of photovoltaic supports, in particular to a mountain flexible photovoltaic support cable force monitoring assembly, a monitoring system and a use method. A mountain flexible photovoltaic support cable force monitoring assembly comprises a bearing cable suitable for being connected with a photovoltaic panel of a photovoltaic support; the grating optical fiber sensor is arranged on the bearing cable, and the grating optical fiber sensor is used for sensing the deformation of the bearing cable; and the controller is in line connection with the grating optical fiber sensor, and the controller is used for monitoring the stress state of the bearing cable in real time. The invention aims to solve the technical problem that a flexible photovoltaic support system in the prior art is often constructed according to design requirements during construction, but after construction is completed, monitoring on the stress state of a bearing cable is neglected, and potential safety hazards are likely to be left.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic supports, and in particular to a cable force monitoring component, a monitoring system and a use method of a mountain flexible photovoltaic support. Background Art

[0002] China has vigorously promoted photovoltaic power generation technology, of which ground photovoltaic accounts for a large proportion. Photovoltaic systems are mainly composed of components, brackets, inverters, cables and control equipment, and brackets are an important component. The brackets support the photovoltaic panels to form the best inclination angle. The design of the brackets in many photovoltaic projects plays a decisive role. For example, in places with poor terrain such as mountains and fish ponds, the selection of the photovoltaic bracket structure is the key to the project. The flexible photovoltaic bracket system is a new type of support system that simplifies the component bracket system by fixing the photovoltaic components on the load-bearing cables tensioned between two columns.

[0003] Existing flexible photovoltaic support systems are often constructed according to design requirements during construction, but after the construction is completed, the monitoring of the stress state of the load-bearing cables is ignored, which can easily leave safety hazards. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect that the flexible photovoltaic support system in the prior art is often constructed according to the design requirements, but after the construction is completed, the monitoring of the stress state of the load-bearing cable is ignored, which easily leaves a safety hazard, thereby providing a mountain flexible photovoltaic support cable force monitoring component, a monitoring system and a use method.

[0005] In order to solve the above problems, the present invention provides a mountain flexible photovoltaic support cable force monitoring component, comprising:

[0006] A load-bearing cable, wherein the load-bearing cable is suitable for connecting to a photovoltaic panel of a photovoltaic support;

[0007] A grating optical fiber sensor is arranged on the load-bearing cable, and the grating optical fiber sensor is used to sense the deformation of the load-bearing cable;

[0008] A controller is connected to the grating optical fiber sensor circuit, and the controller is used to monitor the stress state of the load-bearing cable in real time.

[0009] Optionally, a modem is further included, and the modem is used to receive the optical fiber signal of the grating optical fiber sensor.

[0010] Optionally, the photovoltaic support includes a plurality of support columns, a plurality of photovoltaic panels are arranged between two adjacent support columns, the photovoltaic panels are arranged in parallel, and a load-bearing cable is provided on both sides of each photovoltaic panel.

[0011] Optionally, the plurality of support columns include two end columns and a plurality of intermediate columns, the plurality of intermediate columns are arranged between the two end columns, and both ends of the load-bearing cable pass through the end columns respectively and are fixedly connected to the ground.

[0012] Optionally, a grating optical fiber sensor is provided on both sides of the end column of the load-bearing cable, a grating optical fiber sensor is provided on both sides of the middle column of the load-bearing cable, a grating optical fiber sensor is provided in the middle position of the adjacent middle column of the load-bearing cable, and a grating optical fiber sensor is provided in the middle position of the adjacent middle column and the end column of the load-bearing cable.

[0013] Optionally, the initial wavelength of the optical fiber sensor received by the modem is λ 0 , when the strain ε sensed by the grating fiber sensor g When the modem measures the central wavelength of the grating fiber sensor, B ,λ B With λ 0 The difference is the wavelength change Δλ, which has the following relationship with the effective refractive index, Poisson's ratio and axial strain of the optical fiber:

[0014]

[0015] Among them, ε g is the axial strain of the grating fiber sensor, neff is the effective refractive index, p11 and p12 are the elastic-optic constants, and v is the Poisson's ratio;

[0016] make

[0017] Pe is the effective elastic-optic coefficient. The Pe value of a specific optical fiber material is a fixed value provided by the manufacturer.

[0018] get:

[0019] The grating fiber sensor is fixed on the load-bearing cable, and there is a deviation between the deformation of the load-bearing cable and the deformation of the grating fiber sensor. k =β·ε g , where β is the strain correction coefficient of the grating fiber sensor, ε k is the axial strain of the load-bearing cable;

[0020] Assuming the cable diameter d, stress σ, allowable stress of the cable [σ], cable area Au, and elastic modulus E of the cable, the axial force F of the cable is measured. T =σAu=E·εk·Au==E·β·εg·Au,

[0021] get,

[0022] Optionally, the axial force of the load-bearing cable is along the tangent direction of the load-bearing cable curve, and the axial force F at a certain point on the load-bearing cable curve is T The horizontal component of force is F h , the vertical component is F v , the curve function of the load-bearing cable z=z(x), then:

[0023]

[0024] The basic equilibrium differential equation of the load-bearing cable is obtained from the load-bearing cable curve function and the static equilibrium condition of the differential unit as follows:

[0025]

[0026] Among them, γ G , γ w They represent the safety partial factors of the photovoltaic panel's deadweight and wind load respectively.

[0027] A mountain flexible photovoltaic support cable force monitoring system comprises a plurality of groups of the above-mentioned mountain flexible photovoltaic support cable force monitoring components.

[0028] Optionally, a meteorological collection device is also included, and the meteorological collection device is connected to the controller line.

[0029] A method for using a cable force monitoring component of a mountain flexible photovoltaic support, wherein a grating optical fiber sensor senses the deformation of a load-bearing cable, a controller is connected to the grating optical fiber sensor circuit, and the controller monitors the stress state of the load-bearing cable in real time.

[0030] The technical solution of the present invention has the following advantages:

[0031] 1. The cable force monitoring assembly for mountain flexible photovoltaic support provided by the present invention comprises: a load-bearing cable, which is suitable for connecting with the photovoltaic panel of the photovoltaic support; a grating optical fiber sensor, which is arranged on the load-bearing cable, and the grating optical fiber sensor is used to sense the deformation of the load-bearing cable; a controller, which is connected to the grating optical fiber sensor circuit, and the controller is used to monitor the stress state of the load-bearing cable in real time. The grating optical fiber sensor is used to sense the deformation of the load-bearing cable, and the controller is connected to the grating optical fiber sensor circuit, and the controller is used to monitor the stress state of the load-bearing cable in real time.

[0032] 2. The mountain flexible photovoltaic support cable force monitoring assembly provided by the present invention also includes a modem, which is used to receive the optical fiber signal of the grating optical fiber sensor to analyze and resolve the optical fiber signal of the grating optical fiber sensor.

[0033] 3. The mountain flexible photovoltaic support cable force monitoring assembly provided by the present invention comprises a plurality of support columns, a plurality of photovoltaic panels are arranged between two adjacent support columns, the photovoltaic panels are arranged in parallel, and a load-bearing cable is arranged on both sides of each photovoltaic panel. The load-bearing cable supports the photovoltaic panel, and the support column provides support for the load-bearing cable.

[0034] 4. The cable force monitoring assembly for mountain flexible photovoltaic support provided by the present invention comprises a support column including two end columns and a plurality of intermediate columns, wherein the plurality of intermediate columns are arranged between the two end columns, and the two ends of the load-bearing cable respectively pass through the end columns and are fixedly connected to the ground. The intermediate columns provide support for the load-bearing cable to prevent the load-bearing cable from being too long and contacting the ground.

[0035] 5. The mountain flexible photovoltaic support cable force monitoring assembly provided by the present invention has a grating fiber sensor provided on both sides of the end column of the load-bearing cable, a grating fiber sensor provided on both sides of the middle column of the load-bearing cable, a grating fiber sensor provided in the middle position of the adjacent middle column of the load-bearing cable, and a grating fiber sensor provided in the middle position of the adjacent middle column and the end column of the load-bearing cable. Grating fiber sensors are set at different positions to sense the deformation of the load-bearing cable at different positions.

[0036] 6. The mountain flexible photovoltaic support cable force monitoring system provided by the present invention has the advantages described in any of the above items because it adopts the mountain flexible photovoltaic support cable force monitoring component described in any of the above items.

[0037] 7. The mountain flexible photovoltaic support cable force monitoring system provided by the present invention also includes a meteorological collection device, which is connected to the controller line, and the controller receives meteorological information in real time. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 A schematic diagram of a cable force monitoring assembly for a mountain flexible photovoltaic support provided in an embodiment of the present invention;

[0040] Figure 2 A schematic diagram of the layout position of the grating optical fiber sensor of the cable force monitoring assembly of the mountain flexible photovoltaic support provided in the embodiment of the present invention;

[0041] Figure 3This is a schematic diagram of the mountain flexible photovoltaic support cable force monitoring component provided in an embodiment of the present invention being arranged on a hillside.

[0042] Explanation of the reference numerals: 1. load-bearing cable; 2. photovoltaic panel; 3. support column; 31. end column; 32. middle column; 4. grating optical fiber sensor; 5. hillside surface. DETAILED DESCRIPTION

[0043] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0045] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0047] like Figure 1 -3 shows a specific implementation of a mountain flexible photovoltaic support cable force monitoring component, comprising: a plurality of support columns 3, and two load-bearing cables 1 passing through the support columns 3.

[0048] like Figure 1 As shown, a plurality of photovoltaic panels 2 are arranged between two adjacent support columns 3, and two load-bearing cables 1 are connected below each photovoltaic panel 2. Since the load-bearing cables 1 provide support for the photovoltaic panel 2, the load-bearing cables 1 are curved. Figure 3As shown, the support column 3 includes two end columns 31 and three middle columns 32 arranged on the hillside surface 5, wherein the middle column 32 is arranged between the two end columns 31, that is, one end column 31 is arranged at the top of the mountain, one end column 31 is arranged at the bottom of the mountain, and three middle columns 32 are arranged on the hillside, and both ends of each load-bearing cable 1 are respectively passed through the end columns 31 and fixedly connected to the ground, and each load-bearing cable 1 is respectively slidably connected to the middle columns 32, so that the cable force on both sides of the middle columns 32 is kept consistent. It should be noted that the spacing between adjacent end columns 31 and middle columns 32, and the spacing between adjacent middle columns 32 and middle columns 32 are the same.

[0049] To monitor the stress state of the load-bearing cable 1, Figure 2 As shown, each load-bearing cable 1 is provided with a grating optical fiber sensor 4 on both sides of the end column 31, each load-bearing cable 1 is provided with a grating optical fiber sensor 4 on both sides of the middle column 32, each load-bearing cable 1 is provided with a grating optical fiber sensor 4 in the middle position of the adjacent middle column 32, and each load-bearing cable 1 is provided with a grating optical fiber sensor 4 in the middle position of the adjacent middle column 32 and the end column 31. In order to receive and analyze the optical fiber signal of the grating optical fiber sensor 4, a modem and a controller are also included. The modem receives the optical fiber signal of the grating optical fiber sensor 4, and the controller monitors the stress state of the load-bearing cable 1 in real time.

[0050] A mountain flexible photovoltaic support cable force monitoring system comprises several groups of mountain flexible photovoltaic support cable force monitoring components as described in any one of claims 1 to 7, as well as a meteorological collection device and a control room.

[0051] A method for using a cable force monitoring component of a mountain flexible photovoltaic support includes a cable force online monitoring method and a cable force early warning method.

[0052] (1) Online monitoring method of cable force

[0053] During the actual test, the initial wavelength of the optical fiber sensor received by the modem is λ 0 , when the strain ε sensed by the grating fiber sensor 4 g When the change occurs, the central wavelength of the grating optical fiber sensor 4 measured by the modem is λ B ,λ B With λ 0 The difference is the wavelength change Δλ, which has the following relationship with the effective refractive index, Poisson's ratio and axial strain of the optical fiber:

[0054]

[0055] Among them, ε gis the axial strain of the grating optical fiber sensor 4, neff is the effective refractive index, p11 and p12 are elastic-optic constants, and v is the Poisson's ratio;

[0056] make

[0057] Pe is the effective elastic-optic coefficient. The Pe value of a specific optical fiber material is a fixed value provided by the manufacturer.

[0058] get:

[0059] The grating optical fiber sensor 4 is fixed on the supporting cable 1. There is a deviation between the deformation of the supporting cable 1 and the deformation of the grating optical fiber sensor 4. k =β·ε g , where β is the strain correction coefficient of the grating optical fiber sensor 4, ε k is the axial strain of load-bearing cable 1;

[0060] Assuming the diameter of the load-bearing cable 1 is d, the stress is σ, the allowable stress of the load-bearing cable 1 is [σ], the area of ​​the load-bearing cable 1 is Au, and the elastic modulus of the load-bearing cable 1 is E, then the axial force F of the load-bearing cable 1 is measured. T =σAu=E·εk·Au==E·β·εg·Au,

[0061] In fact, there are n load-bearing cables 1 monitored on site. The load-bearing cables 1 monitored during the operation of the photovoltaic power station are F T1 、F T2 、F T3 、F T4 ......F Tn , take the most unfavorable cable force as F T =max(F T1 、F T2 、F T3 、F T4 ......F Tn )

[0062] get, As long as the most unfavorable load-bearing cable 1 tension is less than [σ], the load-bearing cable 1 is considered safe.

[0063] (2) Early warning method of cable force

[0064] The load-bearing cable 1 mainly bears the weight q of the photovoltaic panel 2 G and wind load q w The direction is vertical downward. The curve function of load-bearing cable 1 is z=z(x). The axial force of load-bearing cable 1 is along the tangent direction of the curve of load-bearing cable 1. The axial force F at a certain point on the curve of load-bearing cable 1 is T The horizontal component of force is F h , the vertical component is F v, then the following relationship exists among the three:

[0065]

[0066] The basic equilibrium differential equation of the load-bearing cable 1 is obtained by the curve function of the load-bearing cable 1 and the static equilibrium condition of the differential unit as follows:

[0067]

[0068] Among them, γ G , γ w They represent the safety factors of the self-weight of photovoltaic panel 2 and wind load respectively,

[0069] As for the arrangement position of the load-bearing cable 1 installed on the mountain site, it can be known that the top of the axis position of the first support column 3 between the adjacent support columns 3 is x=0 and z=0, and the top of the axis position of the second support column 3 is x=L and z=c 1 , when the mid-span position x=L / 2, z=0.5c 1 +f 1 , where L is the span of the load-bearing cable 1 between two adjacent support columns 3, c 1 The height difference between two adjacent support columns 3, f 1 is the deflection of the load-bearing cable 1 between two adjacent support columns 3, and after integration, we get: F h =(γ G q G +γ w q w )L 2 / (8f 1 ),

[0070] Solving the relationship between z and x, we get:

[0071] Taking the derivative with respect to x, we get:

[0072] The relationship between the axial force and the horizontal force of the load-bearing cable 1 is as follows:

[0073]

[0074] According to the photovoltaic power station design specifications, the allowable deflection f in the mid-span under the most unfavorable load condition is required to be 1 ≤50 / L. That is, when x=L / 2, f 1 =50 / L, substitute into the above formula, and we get:

[0075]

[0076] Generally speaking, when the flexible photovoltaic bracket is completed, the weight of the photovoltaic panel is q G, photovoltaic load-bearing cable 1 span L and bracket height difference c 1 It can be determined that the axial force F of the load-bearing cable 1 is obtained T and wind load q w The relationship between the wind load and the wind speed can be obtained in advance through the meteorological station data. w Relevant data, that is, through server calculation, it can be predicted whether the cable force is within the safety range allowed by the design. If it exceeds the safety threshold, relevant measures such as adding ground anchors can be taken in advance to ensure safe operation.

[0077] The purpose of cable force monitoring is to directly obtain the axial force of the load-bearing cable 1 through the sensor. The early warning is to calculate the axial force of the cable through the wind load and self-weight load acting on the structure of the load-bearing cable 1 using the method of structural mechanics. The purpose is to accumulate data, verify each other, and form a cable force monitoring database to provide valuable on-site monitoring data for the subsequent more complex mountain flexible photovoltaic power station design and construction.

[0078] During the actual operation, a meteorological collection device will be installed on site to collect meteorological information such as wind load on site in real time. The information can be connected to the signal processing server to obtain the cable force F under the real-time wind load. Tn , compare the data with the cable force data measured by the optical fiber sensor, and accumulate the data to form a cable force monitoring database for the load-bearing cable 1, providing valuable on-site monitoring data for the subsequent design and construction of more complex mountain flexible photovoltaic power stations.

[0079] The present invention provides a cable tension monitoring component, monitoring system and use method for a mountain flexible photovoltaic support, which have the following advantages: (1) The cable tension of the load-bearing cable 1 of the flexible photovoltaic support in complex mountainous terrain is monitored by a grating optical fiber sensor 4 monitoring method, thereby ensuring the safe and healthy operation of the entire photovoltaic system; (2) The cable tension of the load-bearing cable 1 of the flexible photovoltaic support in complex mountainous terrain is warned based on the data of the meteorological department, so that the adverse factors affecting the operation of the entire system can be known in advance, and necessary reliable reinforcement measures can be taken in advance to prevent the entire device from being damaged; (3) A database of cable tension obtained from on-site meteorological station data and on-site measured cable tension data is formed, so as to accumulate experience for the design and construction of more complex mountain flexible photovoltaic power stations.

[0080] Obviously, the above embodiments are merely examples for clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from them are still within the protection scope of the invention.

Claims

1. A mountain flexible photovoltaic support cable force monitoring component, characterized in that: include: A load-bearing cable (1), wherein the load-bearing cable (1) is suitable for being connected to a photovoltaic panel (2) of a photovoltaic support; A grating optical fiber sensor (4) is arranged on the load-bearing cable (1), and the grating optical fiber sensor (4) is used to sense the deformation of the load-bearing cable (1); A controller is connected to a grating optical fiber sensor (4) line, and the controller monitors the stress state of the load-bearing cable (1) in real time.

2. The mountain flexible photovoltaic support cable force monitoring assembly according to claim 1 is characterized in that: It also comprises a modem, which is used to receive the optical fiber signal of the grating optical fiber sensor (4).

3. The mountain flexible photovoltaic support cable force monitoring assembly according to claim 1 is characterized in that: The photovoltaic support comprises a plurality of support columns (3), a plurality of photovoltaic panels (2) are arranged between two adjacent support columns (3), the photovoltaic panels (2) are arranged in parallel, and a load-bearing cable (1) is respectively arranged on both sides of each photovoltaic panel.

4. The mountain flexible photovoltaic support cable force monitoring assembly according to claim 3 is characterized in that: The plurality of support columns (3) include two end columns (31) and a plurality of intermediate columns (32). The plurality of intermediate columns (32) are arranged between the two end columns (31). Both ends of the load-bearing cable (1) pass through the end columns (31) and are fixedly connected to the ground.

5. The mountain flexible photovoltaic support cable force monitoring assembly according to claim 4 is characterized in that: A grating optical fiber sensor (4) is provided on both sides of the load-bearing cable (1) located at the end column (31), a grating optical fiber sensor (4) is provided on both sides of the load-bearing cable (1) located at the middle position of the adjacent middle column (32), and a grating optical fiber sensor (4) is provided on the load-bearing cable (1) located at the middle position of the adjacent middle column (32) and the load-bearing cable (1) located at the middle position of the adjacent middle column (32) and the end column (31).

6. The mountain flexible photovoltaic support cable force monitoring assembly according to claim 2 is characterized in that: The initial wavelength of the optical fiber sensor received by the modem is λ0. When the strain ε sensed by the grating optical fiber sensor (4) is g When the change occurs, the central wavelength of the grating optical fiber sensor (4) measured by the modem is λ B ,λ B The difference from λ0 is the wavelength change Δλ, which has the following relationship with the effective refractive index, Poisson's ratio and axial strain of the optical fiber: Among them, ε g is the axial strain of the grating optical fiber sensor (4), neff is the effective refractive index, p11 and p12 are the elastic-optical constants, and v is the Poisson's ratio; make Pe is the effective elastic-optic coefficient. The Pe value of a specific optical fiber material is a fixed value provided by the manufacturer. get: The grating optical fiber sensor (4) is fixed on the load-bearing cable (1), and there is a deviation between the deformation of the load-bearing cable (1) and the deformation of the grating optical fiber sensor (4), ε k =β·ε g , where β is the strain correction coefficient of the grating fiber sensor (4), ε k is the axial strain of the load-bearing cable (1); Assuming the diameter of the load cable (1) is d, the stress is σ, the allowable stress of the load cable (1) is [σ], the area of ​​the load cable (1) is Au, and the elastic modulus of the load cable (1) is E, then the axial force F of the load cable (1) is measured. T =σAu=E·εk·Au==E·β·εg·Au, get, 7. The mountain flexible photovoltaic support cable force monitoring assembly according to claim 6 is characterized in that: The axial force of the load-bearing cable (1) is along the tangent direction of the load-bearing cable (1) curve. The axial force F at a certain point on the load-bearing cable (1) curve is T The horizontal component of force is F h , the vertical component is F v , the curve function z=z(x) of the load-bearing cable (1), then: The basic equilibrium differential equation of the load-bearing cable (1) is obtained from the curve function of the load-bearing cable (1) and the static equilibrium condition of the differential unit as follows: Among them, γ G , γ w They represent the safety partial factors of the self-weight of the photovoltaic panel (2) and the wind load respectively.

8. A mountain flexible photovoltaic support cable force monitoring system, characterized in that: It comprises several groups of mountain flexible photovoltaic support cable force monitoring components as described in any one of claims 1 to 7.

9. The mountain flexible photovoltaic support cable force monitoring system according to claim 8 is characterized in that: It also includes a meteorological collection device, which is connected to the controller line.

10. A method for using a cable force monitoring component for a mountain flexible photovoltaic support, used for using the cable force monitoring component for a mountain flexible photovoltaic support according to claim 1, characterized in that: The grating optical fiber sensor (4) senses the deformation of the load-bearing cable (1), and the controller is connected to the grating optical fiber sensor (4) through a line, and the controller monitors the stress state of the load-bearing cable (1) in real time.

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