Multi-split conductor icing characteristic test device and torsional rigidity design method thereof

Abstract

The invention discloses a multi-split conductor icing characteristic test device and a torsional rigidity design method thereof. The device comprises two supporting frames and a plurality of multi-split conductor segments arranged between the two supporting frames. The conduction direction of the tension of the horizontal spring is changed through the string, so that the torsional rigidity of the multi-split conductor icing characteristic test device is kept constant during large-angle torsion, and the device can be used for the large-angle torsion icing characteristic test of the multi-split conductor; according to the torsional rigidity design method, on the basis of a modal superposition method and a dynamic similarity criterion, all physical parameters of the multi-bundle conductor icing characteristic test device are obtained, and accurate design of the torsional rigidity of the multi-bundle conductor icing characteristic test device is achieved by adopting different horizontal spring rigidity and torque loading disc radius combinations; and the icing characteristic of any position of any real multi-split conductor can be accurately simulated.

Description

Technical Field

[0001] The present invention belongs to the field of electric power technology and relates to a multi-split conductor icing characteristic test device, in particular to a multi-split conductor icing characteristic test device considering the dynamic torsion of the split conductors icing and a torsional stiffness design method thereof. Background Art

[0002] Icing significantly increases the tension on transmission lines, potentially causing line breakage, damage to hardware, and even tower collapse. Furthermore, the shape of ice on transmission lines can significantly alter aerodynamic parameters such as the three-way force coefficient and aerodynamic derivatives of each conductor segment, affecting the conductor's galloping and windage characteristics. Therefore, studying the ice-covered characteristics of transmission lines to determine the shape, mass, and density of ice on multi-split conductors is of practical significance for early warning and prevention of transmission line disasters.

[0003] At present, the research on the icing characteristics of transmission lines mainly includes field measurements and artificial simulation tests. Real transmission lines need to cross complex terrain and have the characteristics of high operating altitude, which makes on-site observation of ice difficult, and the accuracy of the data obtained is difficult to guarantee. Breakthroughs in electrical testing technology have made it possible to obtain the icing characteristics of transmission lines through indoor tests. However, most existing test devices are rigid segment models. In fact, transmission lines have the characteristics of large structural span and high flexibility. After icing, especially when multi-split conductors are unevenly iced, they will inevitably twist, which will affect the icing process. The use of rigid segment models will lead to large differences between the test results of the icing characteristics of multi-split conductors and the icing characteristics of real transmission lines. Summary of the Invention

[0004] In view of the deficiency that the existing multi-split conductor icing characteristics test device does not take into account the torsion of the split conductors due to uneven icing, which causes large errors in the test results, the present invention proposes a multi-split conductor icing characteristics test device that can be torsion-controlled at a large angle and has constant torsional stiffness. Based on the modal superposition method and the dynamic similarity criterion, a torsional stiffness design method of the device is given, which can simulate the icing characteristics of any real multi-split conductor at any position.

[0005] To this end, the above-mentioned object of the present invention is achieved by the following technical solutions: a multi-split conductor icing characteristic test device, which includes two support frames and a plurality of multi-split conductor segments arranged between the two support frames;

[0006] The top of the support frame is connected to a rolling bearing with a support, and the rolling bearing is fitted with a connecting shaft; the inner end of the connecting shaft is connected to a connecting disc located on the inner side of the support frame, and the outer end of the connecting shaft is connected to a torque loading disc engraved with an angle scale, and the torque loading disc is located on the outer side of the support frame; the outer side of the connecting disc is connected to an end plate located on the inner side of the support frame, so that two symmetrically arranged end plates are formed on the connecting discs of the two support frames, and the end plates are provided with wire holes for multiple split wire segments to pass through;

[0007] One end of the multi-split wire segment is connected to an end plate of a connecting disk, and the other end is connected to an end plate of another connecting disk;

[0008] There is a spring support groove and a positioning piece on each side of the torque loading disc, and a horizontal spring is placed in the spring support groove; one end of the horizontal spring is connected to the corresponding positioning piece, and the other end is connected to the first thin rope, and the other end of the first thin rope passes under the torque loading disc and is wound around a winding groove on the end surface of the torque loading disc; one end of the other horizontal spring is connected to the corresponding positioning piece, and the other end is connected to the second thin rope, and the other end of the second thin rope passes under the torque loading disc and is wound around another winding groove on the end surface of the torque loading disc.

[0009] When the horizontal spring is relaxed, the spring support groove overcomes the gravity of the horizontal spring to avoid generating additional torque, thereby fully ensuring the stability and accuracy of the stiffness provided by the horizontal spring. The torque loading disc is engraved with an angle scale on the disc surface, which can read the torsion angle of the multi-split conductor icing characteristics test device. The first and second thin ropes can both change the transmission direction of the horizontal spring tension. When the torque loading disc is torsionally twisted at a large angle, the horizontal spring can remain horizontal, so that the torsional stiffness of the multi-split conductor icing characteristics test device does not change during the test, and can be used for icing characteristics tests of multi-split conductors with large angle torsion. The rolling bearing with a support can withstand the gravity load of the multi-split conductor segment, limit the horizontal and vertical displacement of the multi-split conductor icing characteristics test device, and accurately transmit the icing torque of the multi-split conductor segment to the torque loading disc.

[0010] Furthermore, the connecting disc is provided with a circle of outer circle threaded holes, and the end plate is provided with threaded holes with a number less than the outer circle threaded holes. The connecting disc and the end plate are connected by fasteners, which is convenient for disassembly and assembly; the end plate is connected to the connecting disc through outer circle screw holes at different positions, which is used to adjust the initial wind attack angle of the multi-split conductor icing characteristics test device.

[0011] Furthermore, the end plate is in the shape of a straight line, a cross, an * or a M, corresponding to the installation of two-split, four-split, six-split and eight-split conductors respectively.

[0012] Furthermore, the support frame includes a crossbeam and a column; one end of the crossbeam is fixed to one column by bolts, and the other end is fixed to another column by bolts; the top surface of the middle part of the crossbeam is connected to the rolling bearing with a support.

[0013] Furthermore, the column is provided with the positioning piece and spring support groove, the positioning piece is a positioning piece with a hole, and the horizontal spring is connected to the hole on the corresponding positioning piece by a bent hook; the column foot at the bottom of the column is vertically fixed to the ground by bolts.

[0014] Furthermore, the angle scale engraved on the torque loading disc is 360 degrees.

[0015] Furthermore, by controlling the length of the thin rope, the two horizontal springs are exactly at their original length before the torque loading disk is twisted. When the torque loading disk is twisted to one side, one horizontal spring is tensioned to provide stiffness, while the other horizontal spring is relaxed and does not provide stiffness, thereby avoiding the springs from being in a compressed state and ensuring the normal progress of the multi-split conductor icing test.

[0016] Furthermore, different combinations of horizontal spring stiffness and torque loading disk radius are used to simulate the torsional stiffness of any real multi-split conductor at any position.

[0017] Another object of the present invention is to address the shortcomings of existing multi-split conductor icing characteristics test devices, which do not consider the torsion caused by uneven icing of the split conductors, resulting in large errors in test results. A method for designing the torsional stiffness of a multi-split conductor icing characteristics test device based on a modal superposition method is provided, which includes the following steps:

[0018] S1. Establish the torsional motion equations of a prototype multi-split conductor under uneven ice loads;

[0019] S2. Based on the modal decomposition method, the torsional response expression of the prototype multi-split conductor is established. Based on the assumption of an orthogonal damping matrix, the orthogonality of the modes is exploited to decouple the torsional motion equations of the multi-degree-of-freedom system, resulting in a single-degree-of-freedom torsional motion equation.

[0020] S3. By adjusting the generalized torque to simulate different forms of uneven icing, calculate the generalized parameters of the nth-order vibration mode of the prototype multi-split conductor;

[0021] S4. Based on the dynamic similarity relationship and dimensional principle, the torsion angle scale ratio γ between the multi-split conductor icing characteristics test device and the prototype multi-split conductor is determined in advance. θ and size reduction ratio γ L, and then determine the similarity ratio coefficients of the remaining parameters in sequence, including the angular acceleration scale ratio, gravity scale ratio, torsional circular frequency scale ratio, torque scale ratio, moment of inertia scale ratio, and torsional stiffness scale ratio of the multi-split conductor icing characteristics test device and the prototype multi-split conductor; determine the torsional circular frequency and moment of inertia of the multi-split conductor icing characteristics test device based on the torsional circular frequency scale ratio, moment of inertia scale ratio, and the torsional circular frequency and moment of inertia of the prototype conductor;

[0022] S5. Based on the torsional circular frequency and moment of inertia of the multi-split conductor icing characteristic test device determined in step S4, select an appropriate horizontal spring stiffness K x The torsional circular frequency of the multi-split conductor icing characteristic test device is adjusted to be consistent with the torsional circular frequency of the prototype multi-split conductor, and the torsional characteristic of the prototype multi-split conductor caused by uneven icing is simulated.

[0023] The present invention has the following beneficial effects: the present invention changes the transmission direction of the horizontal spring tension through a thin rope, so that the torsional stiffness of the multi-split conductor icing characteristic test device remains constant during large-angle torsion, and can be used for large-angle torsion icing characteristic tests of multi-split conductors; the torsional stiffness design method of the multi-split conductor icing characteristic test device of the present invention obtains various physical parameters of the multi-split conductor icing characteristic test device based on the modal superposition method and the dynamic similarity criterion, and by adopting different combinations of horizontal spring stiffness and torque loading disk radius, the torsional stiffness of the multi-split conductor icing characteristic test device is accurately designed, and the icing characteristics of any real multi-split transmission line at any position are accurately simulated. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic structural diagram of a device for testing icing characteristics of multiple-split conductors according to the present invention;

[0025] Figure 2 for Figure 1 Left side view;

[0026] Figure 3 Schematic diagram of geometric parameters of a 500kV two-stage four-split true type transmission line in a specific embodiment of the present invention;

[0027] Figure 4 1st order torsional vibration mode diagram of a true four-split transmission line in a specific embodiment of the present invention;

[0028] Figure 5 A schematic diagram of the torsion of a multi-split wire segment model in a specific embodiment of the present invention;

[0029] In the figure: 1-torque loading disc; 2-rolling bearing with support; 3-connecting shaft; 4-connecting disc; 5-end plate; 6-multi-split wire segment; 7-crossbeam; 8-column; 9-spring support groove; 10-horizontal spring; 11-first thin rope; 12-positioning piece; 13-second thin rope. DETAILED DESCRIPTION

[0030] The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

[0031] This embodiment provides a multi-split conductor icing characteristic test device, referring to Figure 1-2 It consists of two support frames and multiple multi-split conductor segments 6 positioned between them. Each support frame consists of a crossbeam 7 and two uprights 8. One end of the crossbeam 7 is bolted to one upright, and the other end is bolted to the other upright. A rolling bearing 2 with a support is connected to the top surface of the crossbeam. Spacers 12 and spring support slots 9 are welded to the uprights 8. The spacers 12 are perforated, and the footing at the bottom of the uprights is bolted vertically to the ground.

[0032] The rolling bearing 2 with a support is mounted on a connecting shaft 3. The inner end of the connecting shaft 3 is connected to a connecting disc 4 located inside the support frame via four bolts. The outer end of the connecting shaft 3 is connected to a torque-loading disc 1 engraved with a 360-degree angle scale. The torque-loading disc 1 is located outside the support frame and is made of high-strength acrylic material. The disc has two screw holes and is fixed to the connecting shaft 3 via bolts. The outer side of the connecting disc 4 is connected to an end plate 5 located inside the support frame, thereby forming two symmetrically arranged end plates on the connecting discs of the two support frames. The end plates are cross-shaped and are provided with four screw holes and four wire holes for multi-split wire segments 6 to pass through. The end plates 5 are connected to the connecting disc 4 via the four screw holes and to the multi-split wire segments 6 via the four wire holes. One end of each multi-split wire segment is connected to the end plate of one connecting disc, and the other end is connected to the end plate of the other connecting disc.

[0033] There is a spring support groove 9 and a positioning piece 12 on each side of the torque loading disc 1, and a horizontal spring 10 is placed in the spring support groove 9; one end of the horizontal spring is connected to the corresponding positioning piece, and the other end is connected to the first thin rope 11, and the other end of the first thin rope 11 passes under the torque loading disc and is wound around a winding groove on the end face of the torque loading disc; one end of the other horizontal spring is connected to the hole on the corresponding positioning piece by a bent hook, and the other end is connected to the second thin rope 13, and the other end of the second thin rope 13 passes under the torque loading disc and is wound around another winding groove on the end face of the torque loading disc.

[0034] By controlling the length of the string, the two horizontal springs are precisely at their original lengths before the torque-loading disk is twisted. When the disk is twisted to one side, one horizontal spring tightens, providing stiffness, while the other relaxes, providing no stiffness. By combining different horizontal spring stiffnesses with the torque-loading disk radius, the present invention can simulate the torsional stiffness of any position on a real multi-split conductor.

[0035] The connecting disc is made of high-strength acrylic and has four inner and twenty-four outer screw holes. Four bolts are used to connect it to the connecting shaft 3 through the inner screw holes, and four bolts are used to connect it to the end plate 5 through the outer screw holes. The end plate has a smaller number of threaded holes than the outer threaded holes. The end plate is connected to the connecting disc via outer screw holes at different locations, which is used to adjust the initial wind attack angle of the multi-split conductor icing characteristics test device.

[0036] According to different test conditions and site requirements, the present invention can freely adjust the size of the multi-split conductor icing characteristic test device and the material selection of the horizontal spring.

[0037] In this embodiment, the multi-split conductor segment 6 is four-split. Of course, in other embodiments, it can also be two-split, six-split, eight-split, etc., and all fall within the protection scope of the present invention.

[0038] This embodiment also provides a method for designing the torsional stiffness of the multi-split conductor icing characteristic test device, the steps of which are as follows:

[0039] S1. Establish the torsional motion equation of a prototype multi-split conductor under uneven ice load.

[0040] In step S1, the torsional motion equation is:

[0041] [J]{θ”}+[C θ ]{θ'}+[K θ ]{θ}={T} (1)

[0042] In the formula, [J], [K θ ] and [C θ ] are the moment of inertia, torsional stiffness and torsional damping matrix of the prototype multi-split conductor respectively;

[0043] {T} is the torque generated by the prototype multi-split conductor due to uneven ice coverage, which represents the uneven ice coverage at any position of the prototype multi-split conductor; {θ} is the torsional angle response vector of the prototype multi-split conductor; {θ'} is the angular velocity vector of the prototype multi-split conductor;

[0044] {θ”} is the angular acceleration vector of the prototype multi-split conductor.

[0045] S2. Based on the principle of mode decomposition, the torsional response expression of the prototype multi-split conductor is established. Based on the assumption of orthogonal damping matrix, the orthogonality of the modes is used to decouple the torsional motion equation of the multi-degree-of-freedom system to obtain the single-degree-of-freedom torsional motion equation.

[0046] In step S2, the torsional response expression of the prototype multi-split conductor is:

[0047]

[0048] The single degree of freedom torsional motion equation is:

[0049]

[0050] Where θ(t) is the torsion angle matrix of the prototype multi-split conductor at time t; φ n is the nth-order torsional vibration mode of the prototype multi-split conductor; q n (t) is the generalized coordinate corresponding to the nth-order torsional vibration mode of the prototype multi-split conductor; are the torsional damping ratio and torsional vibration circular frequency of the prototype multi-split conductor in the nth mode; q n '(t) is the first-order derivative of the generalized coordinates of the nth vibration mode of the prototype multi-split conductor with respect to time; q n "(t) is the second-order derivative of the generalized coordinates of the nth vibration mode of the prototype multi-split conductor with respect to time, and T(t) is the torque vector exerted on the transmission line due to uneven icing.

[0051] S3. By adjusting the generalized torque to simulate different forms of uneven icing, the generalized parameters of the nth-order vibration mode of the prototype multi-split conductor are calculated.

[0052] In step S3, the formula used to calculate the generalized parameters of the nth-order vibration mode of the prototype multi-split conductor is as follows:

[0053] J n ={φ n} T [J]{φ n} (3a)

[0054] K θn ={φ n} T [K θ ]{φ n} (3b)

[0055]

[0056] Where, J n The nth-order generalized moment of inertia of the prototype multi-split conductor, is the nth-order generalized torsional stiffness of the prototype multi-split conductor, C nis the nth-order generalized damping matrix of the prototype multi-split conductor.

[0057] S4. Based on the dynamic similarity relationship and dimensional principle, the torsion angle scale ratio γ between the multi-split conductor icing characteristics test device and the prototype multi-split conductor is determined in advance. θ and size reduction ratio γ L , and then determine the similarity ratio coefficients of the remaining parameters in turn.

[0058] In step S4, the formula used to determine the similarity ratio coefficients of the remaining parameters is as follows:

[0059]

[0060]

[0061] Where, γ θ” , γ g 、 γ T , γ J and They are the angular acceleration scale ratio, gravity scale ratio, torsional circular frequency scale ratio, torque scale ratio, moment of inertia scale ratio and torsional stiffness scale ratio of the multi-split conductor icing characteristics test device and the prototype multi-split conductor.

[0062] The torsional circular frequency and moment of inertia of the multi-split conductor icing characteristic test device are determined according to the torsional circular frequency scaling ratio, the moment of inertia scaling ratio and the torsional circular frequency and moment of inertia of the prototype conductor.

[0063] S5. Based on the torsional circular frequency and moment of inertia of the multi-split conductor icing characteristic test device determined in step S4, select an appropriate horizontal spring stiffness K x The torsional circular frequency of the multi-split conductor icing characteristic test device is adjusted to be consistent with the torsional circular frequency of the prototype multi-split conductor, and the torsional characteristic of the prototype multi-split conductor caused by uneven icing is simulated.

[0064] In step S5, the horizontal spring stiffness K x The radius R of the torque loading disk is calculated using the following formula:

[0065]

[0066] Where, J m is the moment of inertia of the multi-split conductor icing characteristics test device, is the circular frequency of torsional vibration of the prototype multi-split conductor.

[0067] The following application example describes the specific application of the multi-split conductor icing characteristics test device in the torsional stiffness design method based on the modal superposition method. The main points are as follows:

[0068] (1) Prototype multi-split conductor torsional circular frequency acquisition

[0069] The finite element model of a 500kV two-stage four-split large height difference transmission line is established. Figure 3 The physical parameters of the multi-split conductor sub-conductors are shown in Table 1.

[0070] Table 1

[0071] model Outer diameter / mm Line mass / Kg / m Elastic modulus / MPa Poisson's ratio LGJ-630 / 55 34.32 2.209 65 0.3

[0072] The prototype multi-split conductor was subjected to modal analysis using finite element software, such as Figure 4 As shown, the torsion circle frequency is 0.14885 Hz.

[0073] (2) Determination of physical parameters of the multi-split conductor icing characteristics test device

[0074] The diameter of the sub-conductors and the spacing between the sub-conductors of the multi-split conductor will significantly affect the icing characteristics of the multi-split conductor. Therefore, it is necessary to ensure that the scale ratio of the multi-split conductor icing characteristics test device to the prototype multi-split conductor is γ L =1, after selecting appropriate materials, the moment of inertia of the multi-split conductor icing characteristic test device can be calculated as J m =2.65kgm 2 .

[0075] The multi-split conductor produces uneven ice coverage due to the shielding effect between the sub-conductors, which causes the multi-split conductor to twist as a whole, thus affecting the shielding effect between the sub-conductors. Therefore, in order to accurately simulate the icing characteristics of the multi-split conductor, it is necessary to ensure that the torsion angle scale ratio of the multi-split conductor icing characteristics test device and the prototype multi-split conductor is γ θ =1, according to formula (4a), it is known that the similarity ratio of the torsional circular frequency between the multi-split conductor icing characteristic test device and the prototype multi-split conductor is required.

[0076] like Figure 5 As shown in the figure, the torsional stiffness of the multi-split conductor icing characteristic test device is provided by the horizontal spring and the string. Assume that when the multi-split conductor icing characteristic test device rotates clockwise by an angle θ, the left horizontal spring is in a relaxed state and does not provide tension, while the right horizontal spring is in a stretched state, and the deformation of the right horizontal spring is θR. If the stiffness of the horizontal spring is K x Under the action of two horizontal springs, the restoring torsional moment and torsional stiffness of the multi-split conductor icing characteristic test device are expressed as follows:

[0077] M θ =2K x ·θR·R=2K x θR2 (7a)

[0078]

[0079] Where M θ The restoring torque, K θ is the torsional stiffness of the multi-split conductor icing characteristics test device, and R is the radius of the torque loading disk.

[0080] Determine the radius of the torque loading disk R = 0.15m, and set the moment of inertia of the multi-split conductor icing characteristic test device to J m =2.65kg·m 2 and multi-split conductor icing characteristics test device torsional circular frequency ω θ =0.14485Hz Substituting into formula (7b) we can get the stiffness K of the horizontal spring x =52N / m.

[0081] The above specific embodiments are used to illustrate the present invention and are only preferred embodiments of the present invention, rather than limiting the present invention. Any modifications and changes made to the present invention within the spirit of the present invention and the scope of protection of the claims shall fall within the scope of protection of the present invention.

[0082] In this embodiment, the test site is an artificial climate chamber. Of course, in other embodiments, the device can also be installed in outdoor natural conditions and in environmental scenes such as ice wind tunnels, and all of these fall within the scope of protection of the present invention.

Claims

1. A multi-split conductor icing characteristics test device, characterized in that: It comprises two support frames and a plurality of multi-split conductor segments (6) arranged between the two support frames; The top of the support frame is connected to a rolling bearing (2) with a support, and the rolling bearing (2) is sleeved with a connecting shaft (3); the inner end of the connecting shaft (3) is connected to a connecting disc (4) located on the inner side of the support frame, and the outer end of the connecting shaft (3) is connected to a torque loading disc (1) engraved with an angle scale, and the torque loading disc (1) is located on the outer side of the support frame; the outer side of the connecting disc (4) is connected to an end plate (5) located on the inner side of the support frame, so that two symmetrically arranged end plates are formed on the connecting discs of the two support frames, and the end plates are provided with wire holes for multiple split wire segments to pass through; One end of the multi-split wire segment (6) is connected to an end plate of a connecting disk, and the other end is connected to an end plate of another connecting disk; The torque loading disc (1) is provided with a spring support groove (9) and a positioning plate (12) on both sides, and a horizontal spring (10) is placed in the spring support groove (9); one end of the horizontal spring is connected to the corresponding positioning plate, and the other end is connected to a first thin rope (11), and the other end of the first thin rope passes under the torque loading disc and is wound on a winding groove on the end surface of the torque loading disc; one end of the other horizontal spring is connected to the corresponding positioning plate, and the other end is connected to a second thin rope (13), and the other end of the second thin rope passes under the torque loading disc and is wound on another winding groove on the end surface of the torque loading disc.

2. A multi-split conductor icing characteristics test device according to claim 1, characterized in that: The connecting disc (4) is provided with a circle of outer circle threaded holes, the end plate is provided with threaded holes whose number is less than the outer circle threaded holes, and the connecting disc and the end plate are connected by fasteners; the end plate is connected to the connecting disc by outer circle screw holes at different positions, and is used to adjust the initial wind attack angle of the multi-split conductor icing characteristic test device.

3. The multi-split conductor icing characteristic test device according to claim 1, characterized in that: The end plate (5) is in the shape of a straight line, a cross, an * or a rice.

4. The multi-split conductor icing characteristic test device according to claim 1, characterized in that: The support frame comprises a crossbeam (7) and a column (8); one end of the crossbeam is fixed to one column by bolts, and the other end is fixed to another column by bolts; the top surface of the middle part of the crossbeam is connected to the rolling bearing with a support.

5. The multi-split conductor icing characteristic test device according to claim 4, characterized in that: The column (8) is provided with the positioning piece and the spring support groove, the positioning piece is a positioning piece with a hole, and the horizontal spring is connected with the hole on the corresponding positioning piece by a hook; the column foot at the bottom of the column is vertically fixed to the ground by bolts.

6. The multi-split conductor icing characteristic test device according to claim 1, characterized in that: The angle scale engraved on the torque loading disc is 360 degrees.

7. The multi-split conductor icing characteristic test device according to claim 1, characterized in that: By controlling the length of the thin rope, the two horizontal springs are just at their original lengths before the torque loading disc is twisted. When the torque loading disc is twisted to one side, one horizontal spring is tensioned to provide stiffness, while the other horizontal spring is relaxed to provide no stiffness.

8. The multi-split conductor icing characteristic test device according to claim 1, characterized in that: By using different combinations of horizontal spring stiffness and torque loading disk radius, the simulation of torsional stiffness at any position of any real multi-split conductor can be achieved.

9. The method for designing torsional stiffness of a multi-split conductor icing characteristic test device according to any one of claims 1 to 8, characterized in that: Includes steps: S1. Establish the torsional motion equation of the prototype multi-split conductor under uneven ice load; S2. According to the principle of mode decomposition method, the torsional response expression of the prototype multi-split conductor is established, and based on the assumption of orthogonal damping matrix, the orthogonality of the mode is used to decouple the torsional motion equation of the multi-degree-of-freedom system to obtain the single-degree-of-freedom torsional motion equation; S3. By adjusting the generalized torque to simulate different uneven icing forms, the generalized parameters of the nth-order vibration mode of the prototype multi-split conductor are calculated; S4. Based on the dynamic similarity relationship and dimensional principle, the torsion angle scale ratio γ between the multi-split conductor ice-covered characteristic test device and the prototype multi-split conductor is determined in advance. θ and size reduction ratio γ L , and then determine the similarity ratio coefficients of the remaining parameters in sequence, including the angular acceleration scaling ratio, gravity scaling ratio, torsion circular frequency scaling ratio, torque scaling ratio, moment of inertia scaling ratio and torsion stiffness scaling ratio of the multi-split conductor icing characteristics test device and the prototype multi-split conductor; determine the torsion circular frequency and moment of inertia of the multi-split conductor icing characteristics test device according to the torsion circular frequency scaling ratio, moment of inertia scaling ratio and the torsion circular frequency and moment of inertia of the prototype conductor; S5. Based on the torsional circular frequency and moment of inertia of the multi-split conductor icing characteristic test device determined in step S4, by selecting an appropriate horizontal spring stiffness K x The torsion circular frequency of the multi-split conductor icing characteristic test device is adjusted to be consistent with the torsion circular frequency of the prototype multi-split conductor, thereby simulating the torsion characteristic of the prototype multi-split conductor caused by uneven icing.

10. The torsional stiffness design method according to claim 9, characterized in that: In step S1, the torsional motion equation is: [J]{θ”}+[C θ ]{θ'}+[K θ ]{θ}={T} (1) In the formula, [J], [K θ ] and [C θ ] are the moment of inertia, torsional stiffness and torsional damping matrix of the prototype multi-split conductor respectively; {T} is the torque generated by the prototype multi-split conductor due to uneven icing, which represents the uneven icing at any position of the prototype multi-split conductor; {θ} is the torsional angle response vector of the prototype multi-split conductor; {θ'} is the angular velocity vector of the prototype multi-split conductor; {θ”} is the angular acceleration vector of the prototype multi-split conductor; In step S2, the torsional response expression of the prototype multi-split conductor is: The single degree of freedom torsional motion equation is: Where θ(t) is the torsion angle matrix of the prototype multi-split conductor at time t; φ n is the nth order torsional vibration mode of the prototype multi-split conductor; q n (t) is the generalized coordinate corresponding to the nth-order torsional vibration mode of the prototype multi-split conductor; are the torsional damping ratio and torsional vibration circular frequency of the prototype multi-split conductor in the nth order mode; q n '(t) is the first-order derivative of the generalized coordinates of the nth vibration mode of the prototype multi-split conductor with respect to time; q n ” (t) is the second-order derivative of the generalized coordinates of the nth vibration mode of the prototype multi-split conductor with respect to time, T(t) is the torque vector of the transmission line due to uneven ice coating; In step S3, the formula used to calculate the generalized parameters of the nth-order vibration mode of the prototype multi-split conductor is as follows: J n ={φ n } T [J]{φ n }(3a) K θn ={φ n } T [K θ ]{φ n }(3b) In the formula, J n The nth-order generalized moment of inertia of the prototype multi-split conductor, is the nth-order generalized torsional stiffness of the prototype multi-split conductor, C n is the nth order generalized damping matrix of the prototype multi-split conductor; In step S4, the formula used to determine the similarity ratio coefficients of the remaining parameters is as follows: In the formula, γ θ” , γ g , γ T , γ J and They are the angular acceleration scale ratio, gravity scale ratio, torsional circular frequency scale ratio, torque scale ratio, moment of inertia scale ratio and torsional stiffness scale ratio of the multi-split conductor ice-covering characteristic test device and the prototype multi-split conductor respectively; In step S5, the horizontal spring stiffness K x The radius R of the torque loading disk is calculated using the following formula: In the formula, J m is the moment of inertia of the multi-split conductor icing characteristics test device, is the torsional vibration circular frequency of the prototype multi-split conductor.

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