Device and Method for Suppressing Aeolian Vibration of Transmission Conductors on Transmission Towers

Abstract

The present invention provides a device and method for suppressing the wind and rain induced vibration of transmission conductors on transmission towers, characterized in that: a plurality of short sheaths with elliptical rings are provided on the transmission conductors to disrupt the original water path on the transmission conductors, making the water film form on the surface of the transmission conductors become disordered, hindering the periodic flow of the water film, preventing the formation of the periodically changing aerodynamic force generated on the surface of the transmission conductors, and thus suppressing the large-amplitude vibration of the transmission conductors. The elliptical rings can disrupt the original water path on the surface of the transmission conductors, making the water film form on the surface of the transmission conductors become disordered, hindering the periodic flow of the water film, preventing the formation of the periodically changing aerodynamic force generated on the surface of the transmission conductors, and thus suppressing the wind and rain induced vibration of the transmission conductors.

Description

Technical Field

[0001] The present invention belongs to the technical fields of power transmission engineering and power facilities, and particularly relates to a device and method for suppressing the wind-rain induced vibration of transmission conductors on transmission towers, and in particular to a wireless long-distance chain self-organizing network method for a transmission Internet of Things. Background Art

[0002] As an important carrier for power transmission and distribution, the amount of transmission conductors used is increasing day by day to ensure people's livelihood work.

[0003] Due to the vast territory of our country, with complex landforms and terrains, including five types of landforms: plains, plateaus, mountains, hills, and basins, and special requirements for the location of power stations, the requirements for the connection of transmission circuits in various places are relatively high. The transmission conductor towers are getting taller, the span between two towers is getting larger, the cross-section of the transmission conductors is getting thicker, and the overall flexibility is getting stronger, etc.

[0004] Due to the above characteristics of the transmission conductors, the transmission conductors are extremely prone to vibration under external loads, such as wind loads; according to actual engineering cases, it is found that when under the combined action of wind and rain, the wind-rain induced vibration phenomenon often occurs in transmission conductors. The wind-rain induced vibration phenomenon is that when in windy and rainy weather, the water line formed on the surface of the transmission conductor changes the cross-sectional shape of the transmission conductor. When there is a wind load, it changes the aerodynamic force on the surface of the transmission conductor, and the transmission conductor is difficult to maintain its inherent stability, thereby generating large-amplitude, low-frequency and extremely harmful vibrations.

[0005] Under long-term vibration, the transmission conductors will suffer fatigue damage, resulting in wear of fittings, strand breakage and broken strands of transmission conductors, and damage to the towers, seriously affecting the normal power transmission work of the transmission conductors and bringing great inconvenience to people's life and work. Therefore, it is very necessary to develop a device or structure that can suppress the wind-rain induced vibration of transmission conductors on transmission towers. Summary of the Invention

[0006] In view of this, in order to overcome the defects and deficiencies of the prior art and solve the problem of large-amplitude vibration of transmission conductors under wind-rain conditions, resulting in huge economic losses, the purpose of the present invention is to provide a device and method for suppressing the wind-rain induced vibration of transmission conductors on transmission towers. The device includes a short sheath with elliptical rings arranged along the transmission conductor, and the two are rigidly connected without gaps. The size of the elliptical ring is 13 mm in width and 5 mm in height; the distance between adjacent elliptical rings is D, and D is the inner diameter of the short sheath; the elliptical cross-section of the elliptical ring is sleeved on the surface of the short sheath at an angle of 45° to the axial direction of the transmission conductor; the elliptical ring can destroy the original water path on the surface of the transmission conductor, making the water film form on the surface of the transmission conductor become disordered, hindering the periodic flow of the water film, and preventing the formation of the periodically changing aerodynamic force generated on the surface of the transmission conductor, thereby suppressing the wind-rain induced vibration of the transmission conductor.

[0007] The present invention specifically adopts the following technical solutions:

[0008] A device for suppressing the wind-rain induced vibration of transmission conductors on transmission towers, characterized in that: a plurality of short sleeves with elliptical rings are provided on the transmission conductors, which are used to destroy the original water channels on the transmission conductors, making the water film form on the surface of the transmission conductors disordered, hindering the periodic flow of the water film, and preventing the formation of the periodically changing aerodynamic force generated on the surface of the transmission conductors, thereby suppressing the large-amplitude vibration of the transmission conductors.

[0009] Furthermore, the elliptical ring provided on the short sleeve of the transmission conductor is rigidly connected to the sleeve as a whole, there is no gap between the two, and there is no relative movement in the working state; the short sleeve and the transmission conductor are fixedly connected and there is no relative movement during operation.

[0010] Furthermore, the center of the elliptical ring on the short sleeve provided on the transmission conductor coincides with the center line of the transmission conductor, and the elliptical cross-section forms a 45° angle with the axial direction of the transmission conductor.

[0011] Furthermore, the distance between adjacent elliptical rings is D, and D is the inner diameter of the short sleeve on the surface of the transmission conductor.

[0012] Furthermore, on the unit length of the transmission conductor, the major axes of the positions where each elliptical ring is located are kept parallel and have the same size.

[0013] Furthermore, the width of the elliptical ring is 13 mm and the height is 5 mm.

[0014] Furthermore, its parameter optimization method includes the following steps:

[0015] Step S1: Based on the slip theory and the vibration theory of a single-degree-of-freedom system, establish a theoretical model for wind-rain induced vibration reduction through finite element simulation, analyze the vibration response of the transmission conductor under the combined action of wind and rain, the water film on one circle of the conductor surface, and the variation characteristics of the lift and drag of the transmission conductor, explore the influence of different transmission conductor shapes on the wind-rain induced vibration phenomenon, and determine the shape of the ring set on the transmission conductor surface;

[0016] Step S2: Apply the established theoretical model for wind-rain induced vibration reduction, use the existing transmission conductor model and wind field parameters, numerically solve the examples of the transmission conductor with and without the short sleeve with an elliptical ring under the combined action of wind and rain, obtain a series of numerical results, including the vibration response of the transmission conductor, the variation characteristics of the water film form on the sleeve surface, and the lift time history response, and compare the results obtained by numerical solution with the test data to verify the correctness of the theoretical model and calculation method;

[0017] Step S3: Use the control variable method to change the device parameters, and determine the parameter values of the device for suppressing the wind-rain induced vibration of the transmission conductor by comparing the vibration suppression effects.

[0018] Furthermore, in step S1:

[0019] The motion equation of the water film on the sheath surface is determined by the following formula:

[0020]

[0021] where: ρ is the density of the water film, u is a vector representing the velocity of the water film movement, g N is the gravity component acting on the cross-section of the transmission line, p is the pressure inside the water film, μ is the dynamic viscosity coefficient of water, is the Hamiltonian operator, and Δ is the Laplace operator;

[0022] The vibration equation of the transmission line is determined by the following formula:

[0023]

[0024] In the formula, M is the mass of the cable, is the inertial force acting on the transmission line, is the damping force, Ky is the elastic force, and F y is the lift force received by the transmission line;

[0025] The lift force F of the transmission line y and the drag force F x are determined by the following formula:

[0026]

[0027]

[0028] where: ρ is the density of the water film, v is the velocity of the water film movement, h0 is the thickness of the water film, and F rr (θ) is the tangential component of the force exerted by the water film on the transmission line, and F θθ (θ) is the normal component of the force exerted by the water film on the transmission line;

[0029] Through finite element simulation, input the model parameters of the transmission line, the wind field environment parameters, and the water film parameters, perform dimensionless processing to establish a two-dimensional geometric model of gas-liquid-solid coupling, and sequentially solve the transient wind pressure coefficient Cp and wind friction coefficient Cf that change with time, the lift force and drag force of the transmission line, as well as the displacement, acceleration, and velocity of the transmission line, etc., and then perform the next coupling to finally determine the influence of different transmission line shapes on rain-wind induced vibration.

[0030] Compared with the prior art, the present invention and its preferred embodiments can disrupt the original water channels on the surface of the transmission line by setting a short sheath with an elliptical ring on the transmission line, making the water film morphology disordered, hindering the periodic flow of the water film, and preventing the formation of the periodic aerodynamic force generated on the surface of the transmission line sheath, which is an effective device for suppressing rain-wind induced vibration.

[0031] Due to the presence of the elliptical ring, the main frequency of the water film change at each wind speed is far from the natural frequency of the transmission line. Compared with the working conditions of a smooth circular transmission line, the corresponding energy amplitude around the main frequency is very small, and the periodic characteristics of the water intake line are also greatly reduced.

[0032] The range of the change in the aerodynamic lift of the transmission line with a short sheath with an elliptical ring is greatly reduced; the main frequency of the change in the aerodynamic lift of the transmission line is very different from the self-vibration frequency of the transmission line, and each wind speed can quickly enter a stable state. The corresponding energy amplitude at the main frequency is very small, which can effectively suppress rain-wind induced vibration.

[0033] Arranging a short sheath with an elliptical ring on the transmission line has good damping performance, low manufacturing cost, and high practical value.

[0034] It also provides a related optimization design method for determining the shape and structure of the elliptical ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present invention will be further described in detail below in conjunction with the drawings and specific embodiments:

[0036] The drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0037] Figure 1 is a schematic structural diagram of the device for suppressing rain-wind induced vibration of a transmission line with a short sheath with an elliptical ring in an embodiment of the present invention;

[0038] Figure 2 is Figure 1 a cross-sectional view of the A-A section therein;

[0039] In the figure: 1 - transmission line; 2 - short sheath; 3 - elliptical ring; 4 - aluminum wire; 5 - steel core. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] To make the features and advantages of this patent more obvious and understandable, specific embodiments are given below and described in detail as follows:

[0041] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Usually, the components described and shown in the accompanying drawings here can be combined and designed in different configurations. Therefore, the following detailed description of the selected embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but only represents the selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0042] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0043] The present invention is directed to the phenomenon of rain-wind induced vibration generated by transmission wires under the combined action of wind and rain. The elliptical ring 3 located on the surface short sheath 2 can disrupt the original water path on the transmission wire, making the water film form on the surface of the transmission wire become disordered, hindering the periodic flow of the water film, and preventing the formation of the periodic change of aerodynamic force generated on the transmission wire 1, thereby effectively suppressing the rain-wind induced vibration phenomenon of the transmission wire.

[0044] As Figure 1 、 Figure 2 shown, in this embodiment, as a device for suppressing the rain-wind induced vibration of the transmission wire, first, an elliptical ring 3 is arranged on the surface sheath 2, and the two are rigidly connected as a whole without gaps and without relative movement during operation; then, the short sheath 2 is sleeved on the transmission wire 3, and there is also no relative movement between the two during operation; the aluminum wire 4 tightly wraps around the steel core 5 with the steel core 5 as the center, and then the aluminum wire 4 and the steel core 5 are wrapped inside by the surface short sheath 2.

[0045] As a preferred solution provided in this embodiment, the elliptical ring 3 is arranged at an angle of 45° along the axial direction of the transmission wire, and is evenly distributed at equal intervals along the axial direction of the transmission wire per unit length. The set spacing is D, where D is the inner diameter of the surface short sheath 2. The height of the elliptical ring 3 is 5 mm and the width is 13 mm.

[0046] The major axes of all the elliptical rings 3 arranged per unit length are kept parallel and have the same size and dimension.

[0047] The parameters (diameter, inclination angle, material, length, etc.) of the steel core 5, the aluminum wire 4, and the surface sheath 2 are determined according to the actual working conditions, and the major and minor axes of the elliptical ring 3 change with the size of the transmission wire.

[0048] The specific parameters and selections of the device provided in the above embodiments can be designed and completed through the following steps:

[0049] Step S1: Based on the slip theory and the vibration theory of single-degree-of-freedom systems, a theoretical model for wind-rain induced vibration reduction is established through finite element simulation. Analyze the vibration response of the transmission line under the combined action of wind and rain, the water film on the surface of the sheath, and the variation characteristics of the lift and drag of the transmission line, etc. Explore the influence of different transmission line shapes on the wind-rain induced vibration phenomenon, and determine that a short sheath with an elliptical ring is set on the surface of the transmission line.

[0050] Step S2: Apply the established theoretical model for wind-rain induced vibration reduction, use the existing transmission line model and wind field parameters, conduct numerical solutions for the cases of the transmission line with and without a short sheath with an elliptical ring under the combined action of wind and rain, and obtain a series of numerical results, including the vibration response of the transmission line, the variation characteristics of the surface water film morphology, and the lift time history response, etc. Compare the results obtained from the numerical solution with the experimental data to verify the correctness of the theoretical model and calculation method.

[0051] Step S3: Use the control variable method to change the device parameters, and determine the parameter values of the device for suppressing wind-rain induced vibration of the transmission line by comparing the vibration suppression effects.

[0052] The specific process of the above Step S1 includes the following:

[0053] The motion equation of the water film on the sheath surface is determined by the following formula:

[0054]

[0055] where: ρ is the density inside the water film, u is a vector representing the velocity inside the water film, g N is the component of gravity acting in the cross-section of the transmission line, p is the pressure inside the water film, μ is the dynamic viscosity coefficient of water, and is the Hamiltonian operator, and Δ is the Laplace operator.

[0056] The vibration equation of the transmission line is determined by the following formula:

[0057]

[0058] In the formula, M is the mass of the cable, is the inertial force acting on the transmission line, is the damping force, Ky is the elastic force, F y is the lift force received by the transmission line.

[0059] The lift force F of the transmission line y , and the drag force F x are determined by the following formula:

[0060]

[0061]

[0062] where: ρ is the density inside the water film, v is the velocity inside the water film, h0 is the thickness of the water film, and F rr (θ) is the tangential component of the force exerted by the water film on the transmission line, and F θθ (θ) is the normal component of the force exerted by the water film on the transmission line.

[0063] Through finite element simulation, input the model parameters of the transmission line, the parameters of the wind field environment, and the parameters of the water film, etc., perform dimensionless processing on them, establish a two-dimensional geometric model of gas-liquid-solid coupling, and successively solve the transient wind pressure coefficient Cp and wind friction coefficient Cf that change with time, the lift and drag of the transmission line, as well as the displacement, acceleration, and velocity of the transmission line, etc., and then perform the next step of coupling to finally determine the influence of different transmission line shapes on rain-wind induced vibration.

[0064] During operation, under the combined action of wind and rain, a continuous water line is formed on the surface sheath of the transmission line, thereby changing the cross-sectional shape of the transmission line and making it aerodynamically unstable in the airflow, which in turn causes large-amplitude vibration of the transmission line. When a short sheath with an elliptical ring is set on the transmission line, the original water flow route is changed, and the continuity of the water line is broken, which can effectively suppress the rain-wind induced vibration phenomenon.

[0065] The above is only a preferred embodiment of the present invention, and it is not a limitation of the present invention in other forms. Any person skilled in the art may use the disclosed technical content to make changes or modifications into equivalent embodiments with equivalent changes. However, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution content of the present invention still fall within the protection scope of the technical solution of the present invention.

[0066] This patent is not limited to the above best implementation manner. Anyone inspired by this patent can obtain other various forms of devices and methods for suppressing rain-wind induced vibration of transmission lines on transmission towers. All equal changes and modifications made according to the scope of the patent application of the present invention shall fall within the coverage scope of this patent.

Claims

1. A device for suppressing wind-rain induced vibration of transmission lines on a transmission tower, characterized by: The transmission line is equipped with multiple short sheaths with elliptical rings to disrupt the original water path on the transmission line, making the water film on the surface of the transmission line disordered, hindering the periodic flow of the water film, and preventing the formation of the periodic aerodynamic force generated on the surface of the transmission line, thereby suppressing the large-scale vibration of the transmission line; The short sheath and the elliptical ring set on the transmission line are rigidly connected as a whole, with no gap between them and no relative movement in the working state; the short sheath and the transmission line are fixedly connected; The center of the elliptical ring on the short sheath provided on the transmission conductor coincides with the centerline of the transmission conductor, and the elliptical cross section forms an angle of 45° with the axis of the transmission conductor; The parameter optimization method includes the following steps: Step S1: Based on the slip theory and the single-degree-of-freedom system vibration theory, a theoretical model for wind-rain-induced vibration reduction is established through finite element simulation. The vibration response of a transmission line with an arbitrary two-dimensional cross-sectional shape under the combined action of wind and rain, the water film around the surface of the conductor, and the lift and drag variation characteristics of the transmission line are analyzed. The influence of different transmission line shapes on the wind-rain-induced vibration phenomenon is explored, and the installation of a short sheath with an elliptical ring on the surface of the transmission line is determined. Step S2: Applying the established theoretical model for wind-rain-induced vibration reduction, using the existing transmission line model and wind field parameters, a numerical solution is performed for transmission lines with and without short elliptical ring sheaths under the combined action of wind and rain. A series of numerical results are obtained, including the vibration response of the transmission line, the morphological characteristics of the water film on the sheath surface, and the time-history response of the lift. The numerical results are compared with the experimental data to verify the correctness of the theoretical model and calculation method. Step S3: using the control variable method to change the device parameters, and by comparing the vibration suppression effects, determining the parameter values of the device for suppressing wind-rain-induced vibration of the transmission line; In step S1, through finite element simulation, the transmission line model parameters, wind field environment parameters and water film parameters are input, and dimensionless processing is performed to establish a two-dimensional geometric model of gas-liquid-solid coupling. The transient wind pressure coefficient Cp and wind friction coefficient Cf that change with time, the lift and drag of the transmission line, and the displacement, acceleration and velocity of the transmission line are solved in turn. Then, the next step of coupling is carried out to finally determine the impact of different transmission line shapes on wind-rain-induced vibration.

2. The device for suppressing wind-rain-induced vibration of transmission wires on a transmission tower according to claim 1, characterized in that: The distance between adjacent elliptical rings is D, where D is the inner diameter of the short sheath on the transmission wire.

3. The device for suppressing wind-rain-induced vibration of transmission wires on a transmission tower according to claim 1, characterized in that: On the unit length of the transmission line, the long axes of each elliptical ring remain parallel and of the same size.

4. The device for suppressing wind-rain-induced vibration of transmission wires on a transmission tower according to claim 1, characterized in that: The elliptical ring has a width of 13 mm and a height of 5 mm.

5. The device for suppressing wind-rain-induced vibration of transmission wires on a transmission tower according to claim 1, characterized in that: In step S1: The motion equation of the water film on the sheath surface is determined by the following formula: Where: ρ is the density of the water film, u is a vector representing the speed of the water film movement, g N is the gravity component acting on the transmission line section, p is the pressure in the water film, μ is the dynamic viscosity coefficient of water, is the Hamiltonian operator, Δ is the Laplace operator; The vibration equation of the transmission line is determined by the following formula: Where M is the mass of the cable, is the inertial force acting on the transmission line, is the damping force, Ky is the elastic force, F y is the lift force on the transmission line; Lift force F on the transmission line y , resistance F x Determined by the following formula: Where: ρ is the density of the water film, v is the velocity of the water film, h0 is the thickness of the water film, F rr (θ) is the tangential component of the force exerted by the water film on the transmission line, F θθ (θ) is the normal component of the force exerted by the water film on the transmission line.

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