A method and system for limiting windage deviation of insulator strings by constructing a controllable stiffness system

Abstract

The present invention discloses a method and system for limiting the windage of an insulator string that constructs a controllable stiffness system, and belongs to the technical field of windage prevention. The existing windage prevention technology does not accurately calculate the stiffness that the additional stiffness device of the insulator string should provide, and the error is relatively large. The present invention discloses a method for limiting the windage of an insulator string that constructs a controllable stiffness system. By analyzing the force of the composite structure of the insulator string and the conductor, a static equilibrium equation and a motion equation are established, and the stiffness that the additional stiffness device AS of the insulator string should provide is solved according to specific data, and the stiffness is substituted into the motion equation for calculation, and the maximum response value of the entire system is obtained to verify whether it meets the requirements of windage control. Then, according to the solved stiffness value that the additional stiffness device AS of the insulator string should provide, the additional stiffness device AS of the insulator string is set, and then the present invention can more accurately calculate the stiffness that the additional stiffness device of the insulator string should provide. The scheme is scientific, reasonable, and feasible.

Description

Technical Field

[0001] The invention relates to a method and a system for limiting windage deviation of an insulator string for constructing a controllable stiffness system, and belongs to the technical field of windage prevention. Background Art

[0002] The transmission line sways in strong winds, causing the conductors and insulators to have wind deflection angles. As the wind force changes, the wind deflection angles also change, causing the conductors and insulators to deflect to varying degrees. When the electrical clearance between the conductor and the tower is insufficient, the air will be broken down, causing discharge tripping.

[0003] When the suspension insulator string is subjected to the wind load component along the cross-arm direction, the lower end of the suspension insulator string will move along the cross-arm direction under the action of the horizontal load and vertical load transmitted by the conductor and the wind load along the cross-arm direction. It is precisely because of this movement along the cross-arm direction that the distance between the conductor and the tower body of the transmission tower will change, which means that the electrical clearance will change in electricity. If the distance is not greater than the minimum distance limit of the specified electrical clearance, the line will be dangerous, and the greatest danger to the structure is the occurrence of wind deflection flashover.

[0004] The manifestation of wind-induced flashover is that when the distance between the conductor connected to the bottom of the insulator string and the transmission tower body is less than the specified electrical clearance limit, the conductor will discharge because the surrounding air will be broken down by the strong voltage. After the wind-induced flashover phenomenon occurs, the automatic compound setting of the line mouth is often difficult to implement, which will cause many serious accidents of the transmission line, including fire, transmission line breakage and power loss.

[0005] Chinese patents: A transient analysis method for wind deflection of a transmission line under the action of a moving thunderstorm (publication number: CN103683086B), a method and device for analyzing dynamic wind deflection of an insulator of a transmission line (publication number: CN109635444A), and a method for determining the maximum dynamic wind deflection angle of a suspension insulator string (publication number: CN109271751A) respectively disclose methods for calculating the wind deflection angle of an insulator string, but none of them involve: how to calculate the stiffness that the insulator string attachment device should provide, and therefore lack a relatively accurate solution for solving the stiffness that the insulator string attachment device should provide.

[0006] If the stiffness of the insulator string additional device is simply set based on experience to perform wind deflection control, there will be a certain degree of subjectivity and randomness, and it will not be possible to ensure that the setting plan of the insulator string additional device is scientific and reasonable, which will lead to a relatively large error and lack of precision in the insulator string wind deflection limitation plan. Summary of the invention

[0007] In view of the defects of the prior art, the purpose of the present invention is to provide a method and system for constructing an insulator string windage limitation system with a controllable stiffness system, which is scientific, reasonable, feasible, and easy to promote and use.

[0008] To achieve the above object, the first technical solution of the present invention is:

[0009] A method for limiting windage of insulator strings by constructing a controllable stiffness system.

[0010] The following steps are involved:

[0011] Step 1: Perform force analysis on the composite structure composed of the insulator string and the conductor of the transmission tower in a static state and a moving state, and establish the static equilibrium equation and motion equation of the insulator string-conductor system;

[0012] Step 2: Calculate the theoretical maximum shear stress through the static equilibrium equation in step 1. According to the moment equilibrium condition, obtain the theoretical windage control stress under the limit state, and preliminarily obtain the stiffness k required by the additional stiffness device AS of the insulator string. AS ;

[0013] Step 3: Substitute the stiffness obtained in step 2 into the motion equation of the insulator string-conductor system to obtain the dynamic response of the insulator string-conductor system, and verify whether the dynamic response of the insulator string-conductor system under wind load meets the requirements of wind deflection control;

[0014] Step 4: According to the verification result in step 3, the stiffness of the additional stiffness device AS of the insulator string is set to form a controllable stiffness system to limit the windage of the insulator string.

[0015] After continuous exploration and experiments, the present invention establishes a static balance equation and a motion equation by analyzing the force of the composite structure of the insulator string and the conductor, solves the stiffness that the additional stiffness device AS of the insulator string should provide according to specific data, substitutes it into the motion equation for calculation, and calculates the maximum response value of the entire system to verify whether it meets the requirement of windage control, and then sets the additional stiffness device AS of the insulator string according to the solved stiffness value that the additional stiffness device AS of the insulator string should provide. Therefore, the present invention can more accurately calculate the stiffness that the additional stiffness device of the insulator string should provide, with small error, detailed scheme, practicability, and scientific and reasonable scheme, which is convenient for popularization and use.

[0016] As the preferred technical measures:

[0017] In step 1, the calculation formula of the static equilibrium equation of the insulator string-conductor system under the limit state is as follows:

[0018] F z =G V sinθ+W V sinθ-G H cosθ-W H cosθ,

[0019] Among them, G V and W V are the deadweight loads of the insulator string and the conductor, G H is the average wind load on the insulator string, W H is the average wind load on the conductor, θ is the wind deflection angle of the insulator string;

[0020] The calculation formula for the average wind load on the insulator string is as follows:

[0021]

[0022] Among them, β Z is the wind vibration coefficient, n is the number of insulators in series vertical to the wind direction, λ1 is the wind load shielding reduction factor of the insulator string along the wind direction, μ Z is the wind pressure height variation coefficient, B3 is the insulator string icing wind load increase coefficient, v is the reference wind speed; A is the windward surface area;

[0023] The average wind load on the conductor is calculated as follows:

[0024]

[0025] Among them, C D is the body drag coefficient, ρ a is the air density, η is the wind incident angle;

[0026] The calculation formula of the windage angle of the insulator string is as follows:

[0027]

[0028] As the preferred technical measures:

[0029] In step 2, the calculation formula of the theoretical windage control stress is as follows:

[0030] F1=αF0;

[0031] α=H0 / H1.

[0032] Wherein, F0 is the allowable stress of the insulator string;

[0033] H0 refers to the distance from the connection between the insulator string hardware and the cross arm to the connection between the insulator string end and the conductor.

[0034] H1 refers to the distance from the connection point between the insulator string hardware and the crossarm to the connection point of the insulator string additional stiffness device AS.

[0035] As the preferred technical measures:

[0036] In step 3, the stiffness of the insulator string additional stiffness device AS is substituted into the motion equation of the insulator string-conductor system.

[0037] Changing the stiffness matrix of the insulator string-conductor system;

[0038] The calculation formula of the stiffness matrix of the insulator string-conductor system is as follows:

[0039]

[0040] K AS =k AS

[0041] γ=-k AS 1 t,i×1

[0042] in, is the stiffness matrix of the insulator string system before installing the additional stiffness device AS of the insulator string; k AS The stiffness of the additional stiffness device AS of the insulator string; 1 t,i×1 It is an i×1 column vector, in which the tth term is equal to 1 and the rest are zero; t is the location of the additional stiffness device AS of the insulator string, which is generally 1; i is the number of measurement points taken on the insulator string, which is determined according to the number of insulators in the insulator string.

[0043] As the preferred technical measures:

[0044] Since the insulator string and the conductor are a multi-degree-of-freedom system, a mathematical model of wind-induced response is constructed according to the equation of motion to calculate the dynamic response of the insulator string-conductor system under wind load.

[0045] The equation of motion is given by:

[0046]

[0047] in, is the acceleration vector of the insulator string conductor system; is the velocity vector of the insulator string conductor system; X(t) and X AS (t) is the displacement vector of the insulator string conductor system and the insulator string additional stiffness device AS degree of freedom; P(t) is the aerodynamic time component vector of the system; Ci×i is the i×i order damping matrix.

[0048] As the preferred technical measures:

[0049] Through the mathematical model of wind-induced response, the force p at different times is calculated according to the wind speed at different time courses. i (t), the specific calculation equations are as follows:

[0050]

[0051] in, Refers to the acceleration of the n×nth item in the acceleration matrix at time t; Refers to the velocity of the n×nth item in the velocity matrix at time t; m n Refers to the mass of the nth point after the insulator string is decomposed into n points; c n Refers to the damping of the n×nth item in the damping matrix; p n (t) refers to the wind load at n points at time t; x AS (t) refers to the displacement of the additional stiffness device AS of the insulator string at time t; n is the number of insulators; k is the bending stiffness of the end of the insulator string.

[0052] As the preferred technical measures:

[0053] According to the calculation equation group, the displacement response X(t) is obtained and converted into the expected extreme value of the displacement response;

[0054] The calculation formula for the expected extreme value of displacement response is as follows:

[0055]

[0056] in, is the expected extreme value of the displacement response of the insulator string at height zm, is the mean displacement response of the insulator string at height zm, σ y (z) is the root mean square of the pulsation response, and g is the peak factor, which is calculated by the empirical formula proposed by Davenport;

[0057] At this time, the windage response of the insulator string end is calculated as follows:

[0058]

[0059] Among them, H1 refers to the distance from the connection point between the insulator string hardware and the crossarm to the connection point of the insulator string additional stiffness device AS;

[0060] The verification formula for windage response is as follows:

[0061] R0≤R and R0≤θ0,

[0062] Wherein, R is the maximum windage angle of the insulator string, and θ0 is the maximum value of the windage angle of the insulator string.

[0063] As the preferred technical measures:

[0064] In step 4, the controllable stiffness system changes the stiffness k of the additional stiffness device AS of the insulator string according to the windage requirements of the insulator string. AS , in order to achieve the effect of controllable stiffness, the specific process is as follows:

[0065] The bending stiffness of the insulator string end is k = EI. Its shear stress is converted into horizontal force through the additional stiffness device and the insulator string additional stiffness device AS, and the bending stiffness is also converted into the tension and compression stiffness of the spring.

[0066] Among them, E is the elastic modulus, I is the moment of inertia, F is the axial tension of the spring, and λ is the axial elongation and compression of the spring. The effect of changing the stiffness is achieved by means of this additional stiffness device.

[0067] The specification of the spring of the adjustment control part of the present invention can meet the wind deflection protection requirements of the transmission tower in different regions and different permanent wind speeds.

[0068] As the preferred technical measures:

[0069] The insulator string additional stiffness device AS transmits force through a gear or a rotary rod device.

[0070] To achieve the above object, the second technical solution of the present invention is:

[0071] An insulator string windage limiting system for establishing a controllable stiffness system is provided with an insulator string additional stiffness device AS, and applies the above-mentioned insulator string windage limiting method for establishing a controllable stiffness system;

[0072] The insulator string additional stiffness device AS includes an input structure, a transmission structure, an output structure, and a control structure;

[0073] The input structure is provided with a rack 1 for obtaining the input displacement of the insulator string;

[0074] The transmission structure is provided with a gear set for amplifying the input displacement of the end of the insulator string multiple times to obtain a rotational displacement of several times;

[0075] The output structure, rack 2, is used to convert rotational displacement into translational displacement and form a reaction force device;

[0076] The control structure is provided with an elastic member, which is used to generate a sufficiently large reaction force by using the elastic member, and transmit it to the end of the insulator string to be converted into a force offsetting force, offset the wind load, and play a role in controlling the wind deflection angle of the insulator string;

[0077] When the insulator string is deflected by wind due to the effect of wind, the insulator string drives the rack to slide;

[0078] The sliding rack drives the gear set to rotate, realizing multi-stage amplification of the rotation displacement of the insulator string;

[0079] The multi-stage amplified rotational displacement drives the rack 2 to produce a large displacement, so that the rack 2 conflicts with the elastic member, and the elastic member produces movement resistance, reducing the movement of the rack 2, thereby realizing the wind deflection control of the insulator string.

[0080] The variable stiffness windage limiting system for an insulator string of the present invention has extremely strong universality and can be applied to various types of insulator strings. At the same time, the additional stiffness device for the insulator string of the present invention is different from the limit limiting device. No matter how slight the windage of the insulator string is, the windage control of the insulator string of the present invention can respond with great response accuracy and a control effect far superior to that of the limit limiting device. At the same time, the load on the insulator string itself is far less than that of other types of control methods.

[0081] Furthermore, the present invention is provided with a rack 1, a gear set, and a rack 2 to form a displacement amplification structure, which converts the acquired large wind load and small rotational displacement into a small force and a large displacement after amplification conversion, thereby being able to effectively sense the tiny wind deflection of the insulator string, improve the reaction accuracy of the anti-wind deflection device, and facilitate control and correction, with a good anti-wind deflection effect, which is conducive to promotion and use. At the same time, the present invention utilizes elastic parts to generate a reaction force, reduce the movement of the rack 2, and realize the wind deflection control of the insulator string. The scheme is simple and practical, has a strong universality, is easy to produce and manufacture, is easy to modify the insulator string, has a short modification period, and has a low modification cost, and can be applied to various types of insulator strings.

[0082] As the preferred technical measures:

[0083] The gear set, rack 2 and elastic member are assembled in a housing.

[0084] The outer wall of the shell is provided with a connection hole for fixing to the lower chord of the cross arm;

[0085] The rack 1 is hinged to the insulator string through a rod;

[0086] The gear set includes gear 1, gear 2, gear 3 and gear 4;

[0087] The radial dimension of the gear 1 is smaller than the radial dimension of the gear 2, and the two are coaxially fixed;

[0088] The radial dimension of the gear 2 is greater than the radial dimension of the gear 3, and the two are tooth-connected;

[0089] The radial dimension of the gear three is smaller than the radial dimension of the gear four, and the two are coaxially fixed, so that the acquired large wind load and small rotational displacement are converted into small force and large displacement after amplification and conversion;

[0090] The gear 1 is tooth-connected with the rack 1 and rotates under the drive of the rack 1;

[0091] The gear four shown is connected with the rack two;

[0092] The rack 2 is driven by the gear 4 to translate and come into conflict with the elastic member;

[0093] The elastic member comprises an elastic member 1 and an elastic member 2;

[0094] The elastic member 1 and the elastic member 2 are respectively assembled at two ends of the rack 2;

[0095] The gear 2 is rotatably connected to the housing via a bearing 1;

[0096] The gear three and the housing rotate through the bearing two.

[0097] Compared with the prior art, the present invention has the following beneficial effects:

[0098] After continuous exploration and experiments, the present invention establishes a static balance equation and a motion equation by analyzing the force of the composite structure of the insulator string and the conductor, solves the stiffness that the additional stiffness device AS of the insulator string should provide according to specific data, substitutes it into the motion equation for calculation, and calculates the maximum response value of the entire system to verify whether it meets the requirements of windage control, and then sets the additional stiffness device AS of the insulator string according to the solved stiffness value that the additional stiffness device AS of the insulator string should provide. The scheme is simple and practical.

[0099] Furthermore, the present invention is provided with a rack 1, a gear set, and a rack 2 to form a displacement amplification structure, which converts the acquired large wind load and small rotational displacement into a small force and a large displacement after amplification conversion, thereby being able to effectively sense the tiny wind deflection of the insulator string, improve the reaction accuracy of the anti-wind deflection device, and facilitate control and correction, with a good anti-wind deflection effect, which is conducive to promotion and use. At the same time, the present invention utilizes elastic parts to generate a reaction force, reduce the movement of the rack 2, and realize the wind deflection control of the insulator string. The scheme is simple and practical, has a strong universality, is easy to produce and manufacture, is easy to modify the insulator string, has a short modification period, and has a low modification cost, and can be applied to various types of insulator strings. BRIEF DESCRIPTION OF THE DRAWINGS

[0100] Figure 1 This is the force analysis diagram for calculating the wind deflection angle of the insulator string using the rigid straight rod method;

[0101] Figure 2 The allowable stress F0 and the controlled stress F1 of the insulator string under the static analysis limit state of the present invention;

[0102] Figure 3 It is a schematic diagram of the analysis of the insulator string-conductor system in the moving state of the present invention;

[0103] Figure 4 A flow chart of the method for limiting windage deviation of an insulator string according to the present invention;

[0104] Figure 5 A structural diagram of an additional stiffness device for an insulator string of the present invention;

[0105] Figure 6 for Figure 5 The structure shown is converted to a certain angle;

[0106] Figure 7 for Figure 6 The structure shown is converted to a certain angle;

[0107] Figure 8 An assembly diagram of an insulator string additional stiffness device applied in the present invention;

[0108] Fig. 9 for Figure 8 The structure shown is converted to a certain angle;

[0109] Fig.10 An assembly diagram of the insulator string additional rigidity device applied to the present invention (assembly of the relevant housing).

[0110] Description of reference numerals:

[0111] 1. Rack 1; 2. Rack 2; 3. Gear 1; 4. Gear 2; 5. Gear 3; 6. Gear 4; 7. Housing; 8. Ball-jointed universal coupling; 9. Insulator string; 10. Crossarm lower chord; 11. Bearing 1; 12. Bearing 2. DETAILED DESCRIPTION

[0112] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0113] On the contrary, the present invention covers any substitution, modification, equivalent method and scheme made on the essence and scope of the present invention as defined by the claims. Further, in order to make the public have a better understanding of the present invention, some specific details are described in detail in the detailed description of the present invention below. Those skilled in the art can fully understand the present invention without the description of these details.

[0114] like Figure 1-Figure 4 As shown, a method for limiting windage deviation of an insulator string by constructing a controllable stiffness system comprises the following steps:

[0115] Step 1: Perform force analysis on the composite structure composed of the insulator string and the conductor of the transmission tower in a static state and a moving state, and establish the static equilibrium equation and motion equation of the insulator string-conductor system;

[0116] Step 2: Obtain the theoretical allowable shear stress through calculation. According to the moment balance condition, obtain the theoretical windage control stress F1=αF0 under the limit state. Preliminary calculation is performed to obtain the stiffness k required by the additional stiffness device (AS) of the insulator string. AS ;

[0117] Among them, α=H0 / H1.

[0118] Among them, H0 refers to the distance from the connection between the insulator string hardware and crossarm to the connection between the insulator string end and the conductor, and H1 refers to the distance from the connection between the insulator string hardware and crossarm to the connection between the insulator string additional stiffness device AS.

[0119] Step 3: By substituting the stiffness of the additional stiffness device AS of the insulator string into the motion equation of the insulator string-conductor system, the dynamic response R0 of the insulator string-conductor system can be obtained to verify whether the dynamic response of the insulator string-conductor system under wind load meets the requirements of wind deflection control;

[0120] Step 4: According to the calculation results, set the stiffness and structure of the insulator string additional stiffness device AS.

[0121] A specific embodiment of the balanced equation of the present invention:

[0122] The equilibrium equation is calculated as follows:

[0123] F z =G V sinθ+W V sinθ-G H cosθ-W H cosθ (1.1)

[0124] The average wind load on the conductor is C D is the body drag coefficient, ρ a is the air density, A is the windward surface area, v is the calculation reference wind speed, and η is the wind incident angle; the average wind load on the insulator string is β Z is the wind vibration coefficient, n is the number of insulators in series vertical to the wind direction, λ1 is the wind load shielding reduction factor of the insulator string along the wind direction, μ Z is the wind pressure height variation coefficient, B3 is the insulator string icing wind load increase coefficient, G V and W V are the deadweight loads of insulator string and conductor respectively.

[0125] A specific embodiment of the present invention for calculating the windage angle and the stiffness required to be provided:

[0126] After substituting the known parameters, the windage angle of the insulator string at this time can be calculated: And the stiffness k required by the additional stiffness device (AS) AS .

[0127] k AS The representative concept is that when the influence of some pulsating wind is ignored, the insulator string is in a balanced state after the wind deflection reaches the maximum value, and the stiffness that the additional stiffness device AS of the insulator string needs to provide is the size.

[0128] A specific embodiment of the stiffness matrix of the present invention:

[0129] After installing the insulator string additional stiffness device AS suspension system, the stiffness matrix of the insulator string structure system can be written as:

[0130]

[0131] K AS =k AS

[0132] γ=-k AS 1 t,i×1

[0133] in, is the stiffness matrix of the insulator string system before installing the additional stiffness device AS of the insulator string; k AS The stiffness of the additional stiffness device AS of the insulator string; 1 t,i×1 It is an i×1 column vector, in which the tth term is equal to 1 and the rest are zero; t is the location of the additional stiffness device AS of the insulator string, which is generally 1; i is the number of measurement points taken on the insulator string, which is determined according to the number of insulators in the insulator string.

[0134] A specific embodiment of the wind-induced response mathematical model of the present invention:

[0135] Simplifying the insulator string and the conductor into a multi-degree-of-freedom system, the mathematical model of the wind-induced response to wind load can be written as:

[0136]

[0137] X ISD and K ISD Change all to X AS and K AS , and we get the following formula:

[0138]

[0139] in, and is the acceleration vector of the insulator string conductor system; is the velocity vector of the insulator string conductor system; X(t) and X AS (t) is the displacement vector of the insulator string conductor system and the insulator string additional stiffness device AS degree of freedom; P(t) is the aerodynamic time component vector of the system.

[0140] Expanding formula 1.2, we can get:

[0141]

[0142] In this equation, Refers to the acceleration of the n×nth item in the acceleration matrix at time t; Refers to the velocity of the n×nth item in the velocity matrix at time t; m n Refers to the mass of the nth point after the insulator string is decomposed into n points; c n Refers to the damping of the n×nth item in the damping matrix; p n (t) refers to the wind load at n points at time t; x AS (t) refers to the displacement of the additional stiffness device AS of the insulator string at time t; n is the number of insulators. The wind speed at different time courses can be used to calculate the force p at different times. i (t).

[0143] Solve equation 1.3 to obtain the displacement response X(t), is the expected extreme value of the displacement response of the insulator string at height zm, is the mean displacement response at height zm, σ y (z) is the root mean square of the pulsation response, and the peak factor g can be calculated using the empirical formula proposed by Davenport.

[0144] At this time, the calculation formula for the windage response of the insulator string end is as follows:

[0145]

[0146] H1 refers to the distance from the connection point between the insulator string hardware and the crossarm to the connection point of the insulator string additional stiffness device AS.

[0147] Furthermore, it is verified that the windage response R0≤R and R0≤θ0, R is the maximum windage angle of the insulator string, and θ0 is the maximum windage angle of the insulator string when the influence of some pulsating wind is ignored.

[0148] A specific embodiment of the stiffness change of the present invention:

[0149] According to the verified k AS , design the additional stiffness device AS of the insulator string, the bending stiffness of the end of the insulator string is k = EI, the shear stress is converted into horizontal force through the additional stiffness device (AS), and the bending stiffness is also converted into the tension and compression stiffness of the spring F is the axial tension of the spring, and λ is the axial elongation and compression of the spring. In this way, the effect of changing the stiffness is achieved.

[0150] A specific embodiment of the insulator string additional stiffness device of the present invention:

[0151] The additional stiffness device (AS) of the insulator string mainly achieves high sensitivity response to wind deviation through the combination of gear sets and high-strength springs. It can generate reaction force even if the deviation angle is very small, taking into account the dynamic change of the reaction force with the wind deviation angle and the ultimate limit.

[0152] A preferred embodiment of the method for limiting windage deviation of an insulator string of the present invention:

[0153] 1. The composite structure composed of the insulator string and the conductor of the transmission tower is subjected to stress analysis in static and dynamic states, and the static equilibrium equation of the insulator string-conductor system is established:

[0154] F0=G V sinθ+W V sinθ-G H cosθ-W H cosθ

[0155] And the equation of motion:

[0156]

[0157] 2. Calculate the windage angle of the insulator string at this time and k AS ;

[0158] 3. Expanding the equation of motion, we can get:

[0159]

[0160] Substitute k AS , solve the equations and obtain the displacement response X(t), is the expected extreme value of the displacement response of the insulator string at height zm, At this time, the windage response of the insulator string end is:

[0161]

[0162] 4. Verify that R0≤R and R≤θ0.

[0163] like Figure 5-Figure 10 As shown, a specific embodiment of the insulator string windage limiting system of the controllable stiffness system constructed by the present invention is as follows:

[0164] An insulator string windage limiting system for constructing a controllable stiffness system comprises an input structure, a transmission structure, an output structure, and a control structure;

[0165] The input structure is provided with a rack 1 for obtaining the displacement of the insulator string 9;

[0166] The transmission structure is provided with a gear set for amplifying the displacement of the end of the insulator string 9 to obtain an amplified rotational displacement;

[0167] The output structure is provided with a rack 2 for converting the rotational displacement into a translational displacement;

[0168] The control structure is provided with an elastic member, which is used to utilize the reaction force of the elastic member to hinder the translation of the rack and realize the windage control of the insulator string 9.

[0169] When the insulator string 9 is deflected by wind due to the effect of wind, the insulator string 9 drives the rack 1 to slide;

[0170] The sliding rack 1 drives the gear set to rotate, realizing multi-stage amplification of the rotation displacement of the insulator string 9;

[0171] The multi-stage amplified rotational displacement drives the rack 2 to produce a large displacement, so that the rack 2 is in conflict with the elastic member, and the elastic member produces movement resistance, reducing the movement of the rack 2, thereby realizing the windage control of the insulator string 9.

[0172] A specific embodiment of the assembly of the rack 1 and the insulator string 9 of the present invention:

[0173] The rack 1 is hinged to a rod for connecting the insulator string 9;

[0174] The rod is connected to one end of the rack 1 through a spherical universal wheel.

[0175] A specific embodiment of the gear set structure of the present invention:

[0176] The gear set includes gear one 3, gear two 4, gear three 5, gear four 6;

[0177] The radial dimension of the gear 1 3 is smaller than the radial dimension of the gear 2 4, and the two are coaxially fixed;

[0178] The radial dimension of the gear 2 4 is greater than the radial dimension of the gear 3 5, and the two are gear-connected;

[0179] The radial dimension of the gear three 5 is smaller than the radial dimension of the gear four 6, and the two are coaxially fixed to achieve multi-stage amplification of the displacement of the insulator string 9.

[0180] The gear 1-3 is gear-connected with the rack 1-1 and rotates under the drive of the rack 1-1;

[0181] The gear 4 6 is gear-connected with the rack 2 2;

[0182] The rack 2 2 is driven by the gear 4 6 to translate and come into conflict with the elastic member.

[0183] A specific embodiment of the elastic member structure of the present invention:

[0184] The elastic member comprises an elastic member 1 and an elastic member 2;

[0185] The elastic member 1 and the elastic member 2 are respectively assembled on the two ends of the rack 2 2 .

[0186] The elastic member 1 and the elastic member 2 are springs respectively. The specifications of the springs can be adjusted to meet the wind deflection protection requirements of transmission towers in different regions and with different permanent wind speeds.

[0187] A specific embodiment of the present invention in which a housing 7 is added:

[0188] Also includes a housing 7 having a receiving cavity;

[0189] The inner cavity of the housing 7 is assembled with a gear set, a rack 2, and an elastic member, and a connecting hole for fixing with the lower chord 10 of the cross arm is provided on the outer wall.

[0190] The gear 2 4 is rotatably connected to the housing 7 via a bearing 11;

[0191] The gear 3 5 and the housing 7 rotate via the bearing 2 12 .

[0192] A preferred specific embodiment of the insulator string windage limiting system of the present invention is:

[0193] The gear set, rack 2 and elastic member are assembled in a housing 7.

[0194] The outer wall of the housing 7 is provided with a connection hole for fixing to the lower chord 10 of the cross arm;

[0195] The rack 1 is hinged to the insulator string 9 through a ball-jointed universal coupling 8;

[0196] The gear set includes gear one 3, gear two 4, gear three 5, gear four 6;

[0197] The radial dimension of the gear 1 3 is smaller than the radial dimension of the gear 2 4, and the two are coaxially fixed;

[0198] The radial dimension of the gear 2 4 is greater than the radial dimension of the gear 3 5, and the two are gear-connected;

[0199] The radial dimension of the gear three 5 is smaller than the radial dimension of the gear four 6, and the two are coaxially fixed, so that the acquired large wind load and small rotational displacement are converted into small force and large displacement after amplification and conversion;

[0200] The gear 1-3 is gear-connected with the rack 1-1 and rotates under the drive of the rack 1-1;

[0201] The gear 4 6 is gear-connected with the rack 2 2;

[0202] The rack 2 is driven by the gear 4 6 to translate and come into conflict with the elastic member;

[0203] The elastic member comprises an elastic member 1 and an elastic member 2;

[0204] The elastic member 1 and the elastic member 2 are respectively assembled at the two ends of the rack 2;

[0205] The gear 2 4 is rotatably connected to the housing 7 via a bearing 11;

[0206] The gear 3 5 and the housing 7 rotate via the bearing 2 12 .

[0207] Gear 1 3 is located directly above rack 1, and gear shafts 1 and 2 are located on the same horizontal line. On gear shaft 1, it is gear 1 3 - bearing 1 1 - gear 2 4 - gear 2 4 - bearing in sequence, and on gear shaft 2, it is bearing 2 12 - gear 3 5 - gear 4 6 - gear 3 5 - bearing in sequence, and rack 2 2 is located directly below gear 4 6 in the coaxial gear.

[0208] The two ends of the ball-jointed universal coupling 8 are respectively hinged with the insulator string 9 and the rack 1, the rack 1 is meshed with the gear 3, the gear 3 is coaxially connected with the two gears 2 4, the gear 2 4 is meshed with the gear 3 5 in the coaxial gear, the coaxial gear is composed of a gear 4 6 and two gears 3 5, among which the gear 4 6 in the coaxial gear is meshed with the rack 2 2, and the rack 2 2 is connected to the spring group.

[0209] The present invention is different from the currently commonly used windage control device. The system of the present invention has extremely strong universality and can be applied to various types of insulator strings 9.

[0210] Furthermore, the additional stiffness device for the insulator string of the present invention is different from the limit limit device. No matter how slight the wind deviation of the insulator string 9 is, the wind deviation control of the new insulator string 9 can respond with great reaction accuracy and much higher control effect than the limit limit device. At the same time, the load on the insulator string 9 itself is much smaller than that of other types of control devices.

[0211] Furthermore, the specification of the adjustment spring of the present invention can meet the demand for wind deflection protection of transmission towers in different regions and with different permanent wind speeds.

[0212] A working principle of the present invention:

[0213] Under the influence of wind force, the insulator string 9 swings, and the ball-jointed universal coupling 8 hinged to the insulator string 9 moves accordingly, and the ball-jointed universal coupling 8 drives the rack 1 to slide back and forth, the rack 1 meshes with the gear 13, the gear 13 rotates, the gear 13 is coaxial with the two-piece gear 24, the two-piece gear 24 rotates, the gear 24 meshes with the coaxial gear 3 5, the coaxial gears rotate, the coaxial gears 4 6 meshes with the rack 22, and the rack 22 slides. At this time, the spring group connected to the rack 22 will reduce the displacement of the rack 22 to achieve the purpose of control.

[0214] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for limiting windage deviation of insulator strings by constructing a controllable stiffness system. It is characterized in that The following steps are involved: Step 1: Perform force analysis on the composite structure composed of the insulator string and the conductor of the transmission tower in a static state and a moving state, and establish the static equilibrium equation and motion equation of the insulator string-conductor system; Step 2: Calculate the theoretical maximum shear stress through the static equilibrium equation in step 1. According to the moment equilibrium condition, obtain the theoretical windage control stress under the limit state, and preliminarily obtain the stiffness k required by the additional stiffness device AS of the insulator string. AS ; Step 3: Substitute the stiffness obtained in step 2 into the motion equation of the insulator string-conductor system to obtain the dynamic response of the insulator string-conductor system, and verify whether the dynamic response of the insulator string-conductor system under wind load meets the requirements of wind deflection control; Step 4: According to the verification result in step 3, the stiffness of the additional stiffness device AS of the insulator string is set to form a controllable stiffness system to limit the windage of the insulator string; In step 1, the calculation formula of the static equilibrium equation of the insulator string-conductor system under the limit state is as follows: F z =G V sinθ+W V sinθ-G H cosθ-W H cosθ, Among them, G V and W V are the deadweight loads of the insulator string and the conductor, G H is the average wind load on the insulator string, W H is the average wind load on the conductor, θ is the wind deflection angle of the insulator string; The calculation formula for the average wind load on the insulator string is as follows: Among them, β Z is the wind vibration coefficient, n is the number of insulators in series vertical to the wind direction, λ1 is the wind load shielding reduction factor of the insulator string along the wind direction, μ Z is the wind pressure height variation coefficient, B3 is the insulator string icing wind load increase coefficient, v is the reference wind speed; A is the windward surface area; The calculation formula for the average wind load on the conductor is as follows: Among them, C D is the body drag coefficient, ρ a is the air density, η is the wind incident angle; The calculation formula of the windage angle of the insulator string is as follows: In step 2, the calculation formula of the theoretical windage control stress is as follows: F1=αF0; α=H0 / H1; Wherein, F0 is the allowable stress of the insulator string; H0 refers to the distance from the connection between the insulator string hardware and the cross arm to the connection between the insulator string end and the conductor. H1 refers to the distance from the connection between the insulator string hardware and the cross arm to the connection between the insulator string additional stiffness device AS; In the step 3, the stiffness of the insulator string additional stiffness device AS is substituted into the motion equation of the insulator string-conductor system to change the stiffness matrix of the insulator string-conductor system; The calculation formula of the stiffness matrix of the insulator string-conductor system is as follows: K AS =k AS γ=-k AS 1 t,i×1 in, is the stiffness matrix of the insulator string system before installing the additional stiffness device AS of the insulator string; k AS The stiffness of the additional stiffness device AS of the insulator string; 1 t,i×1 is an i×1 column vector, in which the tth term is equal to 1 and the rest are zero; t is the location of the additional stiffness device AS of the insulator string; i is the number of measurement points taken on the insulator string, which is determined according to the number of insulators in the insulator string; Since the insulator string and the conductor are a multi-degree-of-freedom system, a mathematical model of wind-induced response is constructed based on the equation of motion to calculate the dynamic response of the insulator string-conductor system under wind load. The equation of motion is given by: is the velocity vector of the insulator string conductor system; in, is the acceleration vector of the insulator string conductor system X(t) and X AS (t) is the displacement vector of the insulator string conductor system and the insulator string additional stiffness device AS degree of freedom; P(t) is the aerodynamic time component vector of the system; C i×i is the i×i order damping matrix.

2. A method for limiting windage of an insulator string with a controllable stiffness system as claimed in claim 1, characterized in that: Through the mathematical model of wind-induced response, the force p at different times is calculated according to the wind speed at different time courses. i (t), the specific calculation equations are as follows: in, Refers to the acceleration of the n×nth item in the acceleration matrix at time t; Refers to the velocity of the n×nth item in the velocity matrix at time t; m n Refers to the mass of the nth point after the insulator string is decomposed into n points; c n Refers to the damping of the n×nth item in the damping matrix; p n (t) refers to the wind load at n points at time t; x AS (t) refers to the displacement of the additional stiffness device AS of the insulator string at time t; n is the number of insulators; k is the bending stiffness of the end of the insulator string.

3. A method for limiting windage of an insulator string with a controllable stiffness system as claimed in claim 2, characterized in that: According to the calculation equation group, the displacement response X(t) is obtained and converted into the expected extreme value of the displacement response; The calculation formula for the expected extreme value of displacement response is as follows: in, is the expected extreme value of the displacement response of the insulator string at height zm, is the mean displacement response of the insulator string at height zm, σ y (z) is the root mean square of the pulsation response, and g is the peak factor, which is calculated by the empirical formula proposed by Davenport; At this time, the windage response of the insulator string end is calculated as follows: Among them, H1 refers to the distance from the connection point between the insulator string hardware and the crossarm to the connection point of the insulator string additional stiffness device AS; The verification formula for windage response is as follows: R0≤R and R0≤θ0, Wherein, R is the maximum windage angle of the insulator string, and θ0 is the maximum value of the windage angle of the insulator string.

4. The method for limiting windage of an insulator string with a controllable stiffness system according to claim 1, characterized in that: In step 4, the controllable stiffness system changes the stiffness k of the additional stiffness device AS of the insulator string according to the windage requirements of the insulator string. AS , in order to achieve the effect of controllable stiffness, the specific process is as follows: The bending stiffness of the insulator string end is k = EI. Its shear stress is converted into horizontal force through the additional stiffness device and the insulator string additional stiffness device AS, and the bending stiffness is also converted into the tension and compression stiffness of the spring. Among them, E is the elastic modulus, I is the moment of inertia, F is the axial tension of the spring, and λ is the axial elongation and compression of the spring. The effect of changing the stiffness is achieved by means of this additional stiffness device.

5. An insulator string windage limiting system with a controllable stiffness system, characterized in that: An insulator string additional stiffness device AS is provided, and an insulator string windage limiting method for constructing a controllable stiffness system as described in any one of claims 1 to 4 is applied; The insulator string additional stiffness device AS includes an input structure, a transmission structure, an output structure, and a control structure; The input structure is provided with a rack 1 (1) for obtaining an input displacement X of the insulator string; The transmission structure is provided with a gear set for amplifying the input displacement X of the end of the insulator string multiple times to obtain a rotational displacement Y1 of several times; The output structure, rack two (2), is used to convert the rotational displacement Y1 into the translational displacement Y2 and form a reaction force device; The control structure is provided with an elastic member, which is used to generate a sufficiently large reaction force F by using the elastic member. S , which is transmitted to the end of the insulator string and converted into a force offsetting force F C , offset the wind load and control the wind deflection angle of the insulator string; When the insulator string (9) is deflected by wind due to the effect of wind, the insulator string (9) drives the rack one (1) to slide; The sliding rack (1) drives the gear set to rotate, thereby realizing multi-stage amplification of the rotation displacement of the insulator string (9); The multi-stage amplified rotational displacement drives the second rack (2) to generate a large displacement, so that the second rack (2) conflicts with the elastic member, and the elastic member generates movement resistance, reducing the movement of the second rack (2), thereby realizing the wind deflection control of the insulator string (9).

6. The insulator string windage limiting system for establishing a controllable stiffness system according to claim 5, characterized in that: The gear set, rack 2 (2), and elastic member are assembled in a housing (7). The outer wall of the housing (7) is provided with a connection hole for fixing to the lower chord rod (10) of the cross arm; The rack 1 (1) is hingedly connected to the insulator string (9) via a rod; The gear set includes gear one (3), gear two (4), gear three (5), and gear four (6); The radial dimension of the gear 1 (3) is smaller than the radial dimension of the gear 2 (4), and the two are coaxially fixed; The radial dimension of the gear 2 (4) is greater than the radial dimension of the gear 3 (5), and the two are gear-connected; The radial dimension of the gear three (5) is smaller than the radial dimension of the gear four (6), and the two are coaxially fixed, so that the acquired large wind load and small rotational displacement are converted into small force and large displacement after amplification and conversion; The gear 1 (3) is gear-connected with the rack 1 (1) and rotates under the drive of the rack 1 (1); The gear 4 (6) is gear-connected with the rack 2 (2); The rack 2 (2) is driven by the gear 4 (6) to translate and come into conflict with the elastic member; The elastic member comprises an elastic member 1 and an elastic member 2; The elastic member 1 and the elastic member 2 are respectively mounted on the two ends of the rack 2 (2); The gear 2 (4) is rotatably connected to the housing (7) via a bearing 1 (11); The gear three (5) and the housing (7) rotate via the bearing two (12).

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