A segmented floating photovoltaic light anchoring system and its design method

Abstract

The present invention discloses a segmented floating photovoltaic light anchoring system, which relates to the technical field of floating photovoltaic power generation on water. It includes a floating photovoltaic array floating on the water surface and an anchor block sunk at the bottom of the water, and also includes a plurality of anchoring brackets arranged outside the floating photovoltaic array, an upper connecting member with one end connected to the anchoring bracket and the other end connected to the middle cable; the middle cable is connected to a lower cable; the lower cable is connected to the bottom connecting member; the bottom connecting member is connected to the anchor block. The present invention adopts a multi-segment mooring scheme of anchor chain - cable - anchor chain, uses a cable with light weight and good elasticity, reduces the phenomenon of concentrated tension, is suitable for large water depth waters over 50m, and improves the safety of the system. The present invention also proposes a design method for this anchoring system.

Description

Technical Field

[0001] The present invention relates to the technical field of floating photovoltaic power generation, and more specifically, it is a segmented floating photovoltaic light anchoring system. The present invention also relates to a design method for such a segmented floating photovoltaic light anchoring system. Background Art

[0002] With the rapid development of the photovoltaic industry, the land resources available for building photovoltaic power stations are becoming increasingly scarce; floating photovoltaics can well solve the problem of limited construction land and have broad development prospects; floating photovoltaic power stations use floating foundations to support equipment such as photovoltaic modules, cables, busbar boxes, and inverters and float on the water surface. The floating foundation is usually restricted to float within a certain area on the water surface through methods such as anchor piles and anchor blocks; the photovoltaic modules are installed on the water body, without occupying land resources, and are suitable for use in areas with limited space. They can be installed using the idle space on waters such as reservoirs, ponds, and lakes. At the same time, they can play a role in shading the water surface, reducing the sunlight on the water surface, thereby reducing the growth of algae in the water, reducing the occurrence of water eutrophication and algal blooms, and having a protective effect on the water ecological environment.

[0003] Most conventional floating photovoltaic projects are built in areas such as reservoirs and fish ponds with a water depth of no more than 30 meters. The main anchoring method is to use stainless steel wire ropes as anchor ropes and connect and fix them to anchor blocks at the bottom of the water; the water depths of most large reservoirs globally are relatively large, reaching 70 meters or even more than 100 meters. The increase in water depth will cause a significant increase in the length and diameter of the steel wire ropes, and the cost of the anchoring system will rise; due to the high density of the steel wire ropes, the connection between the upper end of the anchor rope and the photovoltaic array will bear a large load, and there is a safety hazard of pulling damage or pulling down the outer floating bodies; due to construction errors, the anchor point positions are different, and the anchoring system is prone to tension concentration on-site, causing damage to the array.

[0004] The Chinese patent "A Floating Photovoltaic Anchoring Device with a Ring Structure" (Application No.: 202320476116.7) uses a ring structure to slidably connect with the anchoring column. When the water level rises, there is no need for manual adjustment of the anchoring device, and the floating block can always float above the water surface. When the water level drops, the anchor body can automatically descend, and the anchoring effect will not be reduced; this patent solves the anchoring problem caused by the water level change in conventional water depth waters, but for waters with a large water depth, the anchoring column cannot be constructed and installed. Therefore, in waters with a large water depth, the patent solution is not feasible.

[0005] The Chinese patent "A Design Method for a Floating Photovoltaic Mooring and Anchoring System" (Application No.: 202310733433.7) proposes a general design method for a floating photovoltaic mooring and anchoring system based on existing code requirements, considering the effects of environmental loads, hydrogeology, etc. and the load combination effect. This patent proposes a design method for a general anchoring system, but does not address issues such as large array offsets and large anchoring radii that may occur in complex anchoring systems in deep water environments.

[0006] Therefore, developing a floating photovoltaic anchoring system suitable for large water depths and its design method is a technical problem that urgently needs to be solved in the industry. Summary of the Invention

[0007] The first object of the present invention is to overcome the deficiencies of the above-mentioned background technology and provide a segmented floating photovoltaic lightweight anchoring system.

[0008] The second object of the present invention is to provide a design method for this segmented floating photovoltaic lightweight anchoring system.

[0009] To achieve the above first object, the technical solution of the present invention is: A segmented floating photovoltaic lightweight anchoring system, including a floating photovoltaic array floating on the water surface and an anchor block sunk to the bottom of the water, characterized in that: It further includes a plurality of anchoring brackets arranged outside the floating photovoltaic array, an upper connecting member with one end connected to the anchoring bracket and the other end connected to a middle cable;

[0010] At least one of the middle cables is connected to a lower cable;

[0011] The lower cable is connected to a bottom connecting member;

[0012] The bottom connecting member is connected to the anchor block.

[0013] In the above technical solution, auxiliary floating bodies are arranged outside the bottom of the floating photovoltaic array.

[0014] In the above technical solution, both the upper connecting member and the bottom connecting member are made of metal materials.

[0015] In the above technical solution, both the upper connecting member and the bottom connecting member are anchor chains or steel wires.

[0016] In the above technical solution, one end of the upper connecting member is connected to the anchoring bracket through a first anchoring shackle and the other end is connected to the middle cable through a first transfer shackle;

[0017] The middle cable is connected to the lower cable through a second transfer shackle;

[0018] The lower cable is connected to the bottom connecting member through a third transfer shackle;

[0019] The bottom connecting member is connected to the anchor block through a pre-embedded connecting member.

[0020] In the above technical solution, both the middle cable and the lower cable are synthetic fiber ropes, and the lower cable hangs in the water.

[0021] To achieve the above second object, the technical solution of the present invention is: a design method for a segmented floating photovoltaic light anchoring system, characterized by comprising the following steps:

[0022] Step 1, calculate the environmental loads of the wind, wave, and current from all directions on the floating photovoltaic array in the x, y, and z directions under the extreme working conditions, and select the maximum environmental load as the design environmental load. The design environmental load in the x direction is F x , the design environmental load in the y direction is F y , and the design environmental load in the z direction is F z ;

[0023] Step 2, propose an anchoring distance L m0 , that is, the horizontal distance from the center of the anchor block to the outer anchoring bracket of the floating photovoltaic array; the anchoring distance should meet the following requirements:

[0024]

[0025] Where H max is the designed maximum water depth;

[0026] Step 3, according to the design environmental loads F x , F y , F z ; and the water level, calculate the maximum offset Z m of the floating photovoltaic array at the designed low water level;

[0027] The specific steps are as follows. Step 3.1: Calculate the increase in the draft of the floating photovoltaic array caused by the environmental load F z in the z direction:

[0028]

[0029] Where: D1 is the increased draft under the action of the load; A w is the waterplane area of the array;

[0030] Step 3.2, calculate the offset Z w of the array caused by the water level and draft changes:

[0031]

[0032] Where H min is the designed minimum water depth;

[0033] Step 3.3, the number of anchor blocks in the x direction is N x , the number of anchor blocks in the y direction is N y , preliminarily determine the breaking tension T of the lower cable b Meet the following requirements:

[0034]

[0035]

[0036] T bx ≥ST x

[0037] T by ≥ST y

[0038] Among them: T x is the tension of the lower cable in the x direction, T y are respectively the tensions of the lower cables in the y direction, and S is the safety factor of the anchor rope tension;

[0039] According to T bx and T by select the diameter and material of the lower cable, and thus determine its elongation formula. The cable elongation is related to the tension T and is defined as:

[0040] Y = f(T)

[0041] where Y is the cable elongation;

[0042] Step 3.4: Calculate the offset Z caused by the cable tension deformation due to environmental loads x1 , Z y1 :

[0043]

[0044]

[0045] Among them, L x0 is the sum of the initial lengths of the lower cable and the bottom connection in the x direction, and L y0 is the sum of the initial lengths of the lower cable and the bottom connection in the y direction;

[0046] Step 3.5: The maximum offset of the square matrix is calculated as follows:

[0047] Z mx = N dy × Z x1 + Z w

[0048] Z my = N dy × Z y1 + Zw

[0049] Among them, Z mx is the maximum offset in the x direction; Z my is the maximum offset in the y direction; N dy is the dynamic amplification factor;

[0050] Step 4, review the maximum offset of the square matrix. When the design requirements are not met, re-design the key parameters such as the anchoring distance L m0 , cable material, cable length, etc., and repeat steps 2 - 3 until the maximum offset meets the design requirements: Z m ≤3;

[0051] Step 5, calculate the specifications of each section of the anchor rope. The breaking tensile force of the upper connecting piece and the middle cable shall not be lower than:

[0052]

[0053] Among them: T x1 is the breaking tensile force of the upper connecting piece and the middle cable in the x direction; T y1 is the breaking tensile force of the upper connecting piece and the middle cable in the Y direction; N1 is the number of lower cables connecting the middle cable; θ is the included angle between the middle cable and the lower cable;

[0054] Step 6, the anchor block mass M shall satisfy:

[0055] (M x g - T x cosα)f ≥ F x / N x

[0056] (M y g - T y cosα)f ≥ F y / N y

[0057] Among them: M x is the anchor block mass in the x direction; M y is the anchor block mass in the y direction; α is the included angle between the anchor rope and the vertical direction; g is the gravity coefficient; f is the friction coefficient between the anchor block and the bottom of the water.

[0058] In the above technical solution, in step 3.3, S is not lower than 3.

[0059] In the above technical solution, in step 5, the length of the upper connecting piece is not less than 3m, the length of the middle cable is not less than 2m, and the length of the bottom connecting piece is greater than the length when the anchor rope lies on the bottom at the minimum water level.

[0060] Compared with the prior art, the present invention has the following advantages:

[0061] 1) The present invention adopts a multi-section mooring scheme of anchor chain-cable-anchor chain, and uses a light-weight and elastic cable to reduce the tension concentration phenomenon, adapt to large water depths exceeding 50m, and improve the safety of the system; the present invention also proposes a design method for the anchoring system to reduce the anchoring radius of the anchoring system and limit the array deviation.

[0062] 2) In view of the characteristics of deep water anchoring systems with a water depth of more than 50m, such as long and heavy anchor ropes, small angle with the vertical direction and large vertical tension, the present invention proposes an auxiliary floating body installed below the side of the floating photovoltaic array to reduce the sinking of the side floating body caused by the gravity of the anchor rope and the downward tension.

[0063] 3) The entire anchoring system of the present invention mainly uses cables as the load-bearing structure, giving full play to the characteristics of synthetic fibers such as light weight, high strength and corrosion resistance, and reducing the overall weight of the anchoring system; the upper connecting parts are located near the water surface and are made of metal to prevent the cables from being aged by long-term ultraviolet rays and causing degradation of mechanical properties; bottom connecting parts are used within the friction range of the bottom contacting the bottom of the water, giving full play to the wear resistance of metal that is better than synthetic fibers, and preventing the cables from being damaged and broken due to long-term wear.

[0064] 4) In the present invention, multiple middle cables are connected to a single lower cable, which reduces the anchoring load on a single anchor bracket, reduces the risk of the floating ear plate being pulled and torn when the anchoring system is stressed, and can reduce the number of anchor blocks; the cable has a certain elasticity, and even when there is a certain construction error, each anchor rope can be stressed at the same time through tension deformation, thereby reducing the phenomenon of tension concentration and protecting the floating photovoltaic array.

[0065] 5) The design method of the present invention takes the maximum offset of the floating photovoltaic array as the main control factor. On the basis of ensuring structural safety, it can reduce the spacing between arrays, save water surface space, and improve water surface utilization;

[0066] 6) In addition to considering the array offset caused by water level changes, the design method of the present invention also proposes a calculation method for the array offset caused by cable tension deformation, and accurately evaluates the impact of the cable elongation on the floating photovoltaic array offset. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 It is a schematic elevation view of the present invention.

[0068] Figure 2 It is a top view of embodiment 1 of the present invention.

[0069] Figure 3 It is a top view of embodiment 2 of the present invention.

[0070] Figure 4 It is a design flow chart of the present invention.

[0071] Among them, 1 is a floating PV array, 11 is an auxiliary floating body, 2 is an anchor block, 21 is an embedded connecting piece, 3 is an anchoring bracket, 31 is a first anchoring shackle, 4 is an upper connecting piece, 5 is a middle cable, 51 is a first transfer shackle, 6 is a lower cable, 61 is a second transfer shackle, 7 is a bottom connecting piece, and 71 is a third transfer shackle. Specific implementation mode

[0072] The implementation of the present invention will be described in detail below with reference to the accompanying drawings. However, they do not constitute a limitation to the present invention and are only for illustration purposes. At the same time, the advantages of the present invention will become clearer and easier to understand through the description.

[0073] Referring to the accompanying drawings, it can be seen that a segmented floating PV light anchoring system includes a floating PV array 1 floating on the water surface and an anchor block 2 sunk at the bottom of the water, and also includes a plurality of anchoring brackets 3 arranged outside the floating PV array 1, an upper connecting piece 4 with one end connected to the anchoring bracket 3 and the other end connected to the middle cable 5;

[0074] Not less than one of the middle cables 5 is connected to a lower cable 6; the middle cable 5 has a certain elasticity and is used to connect the upper connecting piece 4 and the lower cable 6. One upper connecting piece 4 corresponds to one middle cable 5, and one or more middle cables 5 are connected to a single lower cable 6;

[0075] The lower cable 6 is connected to the bottom connecting piece 7;

[0076] The bottom connecting piece 7 is connected to the anchor block 2.

[0077] An auxiliary floating body 11 is arranged outside the bottom of the floating PV array 1; the large water depth anchoring system generates a large downward pulling force on the side floating body, and the auxiliary floating body 11 is used to increase the outer buoyancy to avoid the sinking of the operation and maintenance passage;

[0078] Both the upper connecting piece 4 and the bottom connecting piece 7 are made of metal materials, such as galvanized steel or stainless steel.

[0079] Both the upper connecting piece 4 and the bottom connecting piece 7 are anchor chains or steel wires.

[0080] One end of the upper connecting piece 4 is connected to the anchoring bracket 3 through a first anchoring shackle 31, and the other end is connected to the middle cable 5 through a first transfer shackle 51;

[0081] The middle cable 5 is connected to the lower cable 6 through a second transfer shackle 61;

[0082] The lower cable 6 is connected to the bottom connecting piece 7 through a third transfer shackle 71;

[0083] The bottom connecting piece 7 is connected to the anchor block 2 through an embedded connecting piece 21.

[0084] Both the middle cable 5 and the lower cable 6 are synthetic fiber ropes, such as polyester fiber and terylene fiber, etc.; the lower cable 6 hangs in the water and does not contact the bottom of the water.

[0085] The bottom connector 7 is installed on the lying section of the anchoring system.

[0086] A design method for a segmented floating photovoltaic light anchoring system, characterized by comprising the following steps:

[0087] Step 1: Determine the capacity and size of a single floating photovoltaic array 1 according to the shape of the available water area at the project site and the relevant requirements of electrical equipment.

[0088] Step 2: Calculate the environmental loads on the floating photovoltaic array 1 in the x, y, and z directions from wind, waves, and currents from all directions under extreme conditions according to parameters such as the size of the floating photovoltaic array 1, the number of installed components, the component inclination angle, and the draft. Select the maximum environmental load as the design environmental load. The design environmental load in the x direction is F x , the design environmental load in the y direction is F y , and the design environmental load in the z direction is F z ;

[0089] Step 3: Propose an anchoring distance L m0 , that is, the horizontal distance from the center of the anchor block 2 to the outer anchoring bracket 3 of the floating photovoltaic array 1; at the design high water level, the anchor rope is in a tensioned state and the angle with the bottom mud surface is greater than 60 degrees. The anchoring distance should meet the following requirements:

[0090]

[0091] where H max is the design maximum water depth;

[0092] Step 4: Calculate the maximum offset Z of the floating photovoltaic array 1 at the design low water level according to the design environmental loads F x , F y , F z ; and the water level; m ;

[0093] The specific steps are as follows. Step 4.1: Calculate the increase in the draft of the floating photovoltaic array 1 caused by the environmental load F z in the z direction:

[0094]

[0095] where: D1 is the increased draft under the action of the load; A w is the waterplane area of the array;

[0096] Step 4.2, calculate the offset Z of the square array caused by the water level and draft changes w :

[0097]

[0098] where H min is the designed minimum water depth;

[0099] Step 4.3, the number of anchor blocks 2 in the x direction is N x , the number of anchor blocks 2 in the y direction is N y , preliminarily determine the breaking tensile force T of the lower cable 6 b to meet the following requirements:

[0100]

[0101]

[0102] T bx ≥ST x

[0103] T by ≥ST y

[0104] where: T x is the tension of the lower cable 6 in the x direction, T y are respectively the tensions of the lower cable 6 in the y direction, and S is the safety factor of the anchor cable tension;

[0105] According to T bx and T by select the diameter and material of the lower cable 6, and thus determine its elongation formula. The elongation of the cable is related to the tensile force T and is defined as:

[0106] Y = f(T)

[0107] where Y is the elongation of the cable;

[0108] Step 4.4: Calculate the offset Z generated by the cable tension deformation caused by the environmental load x1 , Z y1 :

[0109]

[0110]

[0111] where L x0 is the initial length sum of the lower cable 6 and the bottom connector 7 in the x direction, and L y0 is the initial length sum of the lower cable 6 and the bottom connector 7 in the y direction;

[0112] Step 4.5: The maximum offset of the square matrix is calculated as follows:

[0113] Z mx = N dy × Z x1 + Z w

[0114] Z my = N dy × Z y1 + Z w

[0115] where Z mx is the maximum offset in the x direction; Z my is the maximum offset in the y direction; N dy is the dynamic amplification factor, considering the influence of wave dynamic effects on displacement when wave load is the main load;

[0116] Step 5, review the maximum offset of the square matrix. When the design requirements are not met, re - design the key parameters such as the anchoring distance L m0 , cable material, cable length, etc., and repeat Steps 3 - 4 until the maximum offset meets the design requirements: Z m ≤ 3;

[0117] Step 6, calculate the specifications of each section of the anchor rope. The breaking tensile force of the upper connecting piece 4 and the middle cable 5 shall not be less than:

[0118]

[0119]

[0120] where: T x1 is the breaking tensile force of the upper connecting piece 4 and the middle cable 5 in the x direction; T y1 is the breaking tensile force of the upper connecting piece 4 and the middle cable 5 in the Y direction; N1 is the number of the lower cables 6 connecting the middle cable 5; θ is the included angle between the middle cable 5 and the lower cable 6;

[0121] Step 7, the mass M of the anchor block 2 shall satisfy:

[0122] (M x g - T x cosα)f ≥ F x / N x

[0123] (M y g - T y cosα)f ≥ F y / N y

[0124] where: M x is the mass of the anchor block 2 in the x direction; My The mass of the anchor block 2 in the y direction; α is the angle between the anchor rope and the vertical direction; g is the gravity coefficient; f is the friction coefficient between the anchor block 2 and the bottom of the water.

[0125] In step 4.3, S is not less than 3.

[0126] In step 6, the length of the upper connecting member 4 is not less than 3 m, the length of the middle cable 5 is not less than 2 m, and the length of the bottom connecting member 7 is greater than the length when the anchor rope lies on the bottom at the lowest water level.

[0127] Embodiment 1

[0128] As Figure 2 shown, this embodiment adopts the form of connecting 3 middle cables 5 with 1 lower cable 6. To avoid excessive force on the middle upper connecting member 4 and middle cable 5, the sum of the lengths of the middle upper connecting member 4 and middle cable 5 is slightly greater than the straight-line distance from the second transfer shackle 61 to the middle anchoring bracket 3, that is, the middle cables 5 on both sides are stressed first to produce a certain deformation, and then the 3 middle cables 5 are stressed simultaneously.

[0129] Embodiment 2

[0130] As Figure 3 shown, this embodiment adopts the form of connecting 2 middle cables 5 with 1 lower cable 6, that is, the middle cables 5 on both sides are symmetrically arranged, and the load acting on a single anchoring bracket 3 is halved, which is beneficial to protecting the overall safety of the floating structure.

[0131] Other parts not described belong to the prior art.

Claims

1. A design method for a segmented floating photovoltaic light anchoring system, the segmented floating photovoltaic light anchoring system comprising a floating photovoltaic array (1) floating on the water surface and an anchor block (2) sunk to the bottom of the water, characterized in that: It also includes a plurality of anchoring brackets (3) arranged outside the floating PV array (1), and an upper connecting member (4) with one end connected to the anchoring bracket (3) and the other end connected to the middle cable (5); One end of the upper connecting member (4) is connected to the anchoring bracket (3) through a first anchoring shackle (31), and the other end is connected to the middle cable (5) through a first adapter shackle (51); The middle cable (5) is connected to the lower cable (6) through a second adapter shackle (61); The lower cable (6) is connected to the bottom connecting member (7) through a third adapter shackle (71); The bottom connecting member (7) is connected to the anchor block (2) through a pre-buried connecting member (21); The described design method includes the following steps: Step 1, calculate the environmental loads on the floating PV array (1) from wind, wave and current in all directions under extreme conditions, and select the maximum environmental load as the design environmental load. , , For the environmental loads in three directions, select the maximum environmental load as the design environmental load. The design environmental load in the direction is The design environmental load in the direction is The design environmental load in the direction is Step 2, propose the anchoring distance , that is, the horizontal distance from the center of the anchor block (2) to the outer anchoring bracket (3) of the floating PV array (1); the anchoring distance should meet the following requirements: wherein is the designed maximum water depth; Step 3: According to the designed environmental load , , ; and the water level, calculate the maximum offset of the floating PV array (1) at the designed low water level ; The specific steps are as follows. Step 3.1: Calculate the increase in draft of the floating PV array (1) caused by the environmental load in the direction: Wherein: is the increased draft under the action of the load; is the waterplane area of the phalanx; Step 3.2, calculate the offset of the square array caused by the water level and draft changes : Among them, is the designed minimum water depth; Step 3.3, the number of anchor blocks (2) in the direction is the number of anchor blocks (2) in the direction is Meet the following requirements: Wherein: is the tension of the lower cable (6) in the respectively are the tension of the lower cable (6) in the is the safety factor of the anchor cable tension; According to and select the diameter and material of the lower cable (6) to determine its elongation formula. The elongation of the cable is related to the tensile force and is defined as: wherein is the cable elongation rate; Step 3.4: Calculate the offset caused by the cable tension deformation due to environmental loads : Among them is the initial length sum of the lower cable (6) and the bottom connector (7) in the is the initial length sum of the lower cable (6) and the bottom connector (7) in the Step 3.5: The maximum offset of the array is calculated as follows: Among them, is the maximum offset in the is the maximum offset in the is the dynamic amplification factor; Step 4. Recheck the maximum offset of the square matrix. When the design requirements are not met, redesign the anchoring distance. , cable material, and cable length, and repeat Steps 2 - 3 until the maximum offset meets the design requirements: ； Step 5, calculate the specifications of each section of the anchor rope. The breaking tensile force of the upper connecting member (4) and the middle cable (5) is not less than: Wherein: is the breaking tensile force of the upper connector (4) and the middle cable (5) in the is the breaking tensile force of the upper connector (4) and the middle cable (5) in the is the number of the lower cables (6) connecting the middle cable (5); is the included angle between the middle cable (5) and the lower cable (6). Step 6, the mass M of the anchor block (2) satisfies: Wherein: is the mass of the anchor block (2) in the is the mass of the anchor block (2) in the the included angle between the anchor rope and the vertical direction; the gravity coefficient; the friction coefficient between the anchor block (2) and the bottom of the water.

2. The design method of a segmented floating photovoltaic light anchoring system according to claim 1, characterized in that: An auxiliary floating body (11) is arranged outside the bottom of the floating PV array (1).

3. The design method of a segmented floating photovoltaic light anchoring system according to claim 1, characterized in that: Both the upper connecting member (4) and the bottom connecting member (7) are made of metal materials.

4. The design method of a segmented floating photovoltaic light anchoring system according to claim 3, characterized in that: Both the upper connecting member (4) and the bottom connecting member (7) are anchor chains or steel ropes.

5. The design method of a segmented floating photovoltaic light anchoring system according to claim 1, characterized in that: Both the middle cable (5) and the lower cable (6) are synthetic fiber ropes, and the lower cable (6) hangs in the water.

6. The design method of a segmented floating photovoltaic light anchoring system according to claim 1, characterized in that In step 3.3, not less than 3.

7. The design method of a segmented floating photovoltaic light anchoring system according to claim 1, characterized in that In step 5, the length of the upper connecting member (4) is not less than 3 m, the length of the middle cable (5) is not less than 2 m, and the length of the bottom connecting member (7) is greater than the length when the anchor rope lies on the bottom at the lowest water level.

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