Method for determining windage yaw of ice-coated suspension insulator string in high-altitude area and related system

Abstract

The invention discloses a method and a related system for determining windage yaw of an icing suspension insulator chain in a high altitude area, the system comprises an input unit, a finite element model building unit, a self-weight load applying unit, an instantaneous wind load applying unit and a solving unit, and the method comprises the following steps: firstly, obtaining structure parameters and meteorological parameters of a line; then constructing a finite element model of the suspension insulator string and a connected structure thereof according to the structural parameters of the line; secondly, applying a self-weight load; introducing a resistance coefficient in the simulation of the wind speed field, correcting the air density according to the influence of the altitude and the environment temperature on the air characteristics so as to obtain an instantaneous wind load, and then applying the instantaneous wind load to the finite element model; and finally, solving through finite element software to obtain a node displacement array corresponding to the suspension insulator string, and converting the node displacement array into a corresponding wind deflection angle according to a geometrical relationship. According to the method, the wind load can be accurately applied, the wind deflection angle can be accurately solved, and the obtained wind deflection precision is high.

Description

Technical Field

[0001] The invention relates to a method for determining windage deviation of a suspension insulator string of an ice-covered power transmission line in a high-altitude area and a related system, belonging to the technical field of windage deviation calculation of insulator strings. Background Art

[0002] my country has a vast territory with complex and diverse topography, including mountains, hills, plateaus, plains and basins. The plateau area accounts for more than 1 / 4 of my country's total territory. With the continuous advancement of ultra-high voltage and UHV projects and the rapid development of digital power grid construction, power transmission channels will inevitably cross some high-altitude and heavily iced areas, which undoubtedly poses a great challenge to the disaster resistance of overhead conductors, ground wires, insulator strings and transmission towers in the area. Therefore, maintaining the safe operation of power transmission lines in the area is of great significance to the long-term stable operation of my country's power grid in the plateau area.

[0003] According to feedback from on-site operation and maintenance personnel, flashover accidents caused by strong winds are particularly prominent in plateau areas. Every year, the number of tripping accidents caused by strong winds on lines of different voltage levels accounts for more than 50% of the total number of accidents. Among them, insufficient insulation safety distance caused by wind deviation of suspension insulator strings is the main cause of tripping. If the reclosing fails after wind deviation tripping, the line will be shut down, which will in turn affect the power supply reliability of the power grid and cause huge economic losses to society and the people.

[0004] At the same time, the influence of line icing on the wind deflection of suspension insulator strings has two sides. On the one hand, icing will increase the vertical load of the line structure, thereby increasing the tension on the suspension insulator string, effectively suppressing the occurrence of wind deflection; on the other hand, icing will increase the wind-exposed area of ​​the line structure, thereby increasing the horizontal load of the line structure, thereby promoting the occurrence of wind deflection. Therefore, the actual impact of icing on wind deflection needs to be combined with specific environmental conditions and cannot be generalized, which also causes the complexity of wind deflection problems in high-altitude icing areas. Summary of the invention

[0005] Purpose of the invention: In order to solve the problem of low accuracy of windage calculation in the prior art, the present invention provides a method for determining windage of ice-covered suspension insulator strings in high altitude areas.

[0006] Technical solution: To achieve the above purpose, the technical solution adopted by the present invention is:

[0007] A method for determining windage deviation of an ice-covered suspension insulator string in a high altitude area comprises the following steps:

[0008] Step 1: Obtain the structural parameters and meteorological parameters of the line.

[0009] Step 2: construct a finite element model of the suspension insulator string and its connected structure according to the structural parameters of the line.

[0010] Step 3: Apply deadweight load to the finite element model according to the structural parameters of the line. Determine the simulation of the wind speed field according to the meteorological parameters, introduce the drag coefficient into the simulation of the wind speed field, and correct the air density according to the influence of altitude and ambient temperature on air characteristics to obtain the instantaneous wind load, and then apply the instantaneous wind load to the finite element model.

[0011] Step 4, according to the finite element model, the deadweight load and the instantaneous wind load are solved by the finite element software to obtain the corresponding node displacement array of the suspension insulator string, and then the node displacement array is converted into the corresponding wind deflection angle according to the geometric relationship.

[0012] Preferably, the formula for the instantaneous wind load in step 3 is:

[0013] ;

[0014] In the formula, is the instantaneous wind load in the horizontal direction, is the instantaneous wind load in the vertical direction, He is the local average altitude, T a is the average temperature under local icing conditions, h is the equivalent annular ice thickness, U is the horizontal average wind speed, u is the horizontal fluctuating wind speed, v is the instantaneous fluctuating wind speed in the vertical direction, V is the instantaneous wind speed, The symbol for scientific notation.

[0015] Preferably, the method for obtaining the instantaneous wind load in step 3 is as follows:

[0016] Step 321, in the simulation of the wind speed field, the AR linear filtering method is used to simulate the random pulsating wind speed field in the along-wind and across-wind directions at the spatial point, and then the average wind speed field is superimposed to obtain the actual instantaneous wind speed field of the local area.

[0017] Step 322, calculation of wind load:

[0018] The instantaneous wind load component on the ice-covered section is calculated with the help of the drag coefficient c d And instantaneous wind speed V is calculated:

[0019] ;

[0020] In the formula, F d is the instantaneous wind resistance to the ice-covered section, ρ is the air density under ice-covered conditions, V is the instantaneous wind speed, h is the equivalent annular ice thickness, c d (V,h) is the drag coefficient.

[0021] ;

[0022] Taking into account the influence of altitude and ambient temperature on air characteristics, the air density ρ is corrected using the following formula:

[0023] ;

[0024] Where He is the local average altitude, T a is the average temperature under local icing conditions.

[0025] The instantaneous wind load is converted to the global coordinate system XOY:

[0026] ;

[0027] In the formula, is the instantaneous wind load in the horizontal direction, is the instantaneous wind load in the vertical direction, ρ is the air density under icing conditions, h is the equivalent annular ice thickness, U is the horizontal average wind speed, u is the horizontal pulsating wind speed, c d (V,h) is the drag coefficient, V is the instantaneous wind speed, and v is the instantaneous pulsating wind speed in the vertical direction.

[0028] Preferably, the simulation method of the wind speed field in step 321 is as follows:

[0029] The average wind speed profile of the atmospheric boundary layer within a certain height range is described by the following exponential law:

[0030] ;

[0031] In the formula, is the average wind speed at a height z above the ground, U r is the reference height (z r ) at the average wind speed, z r is the reference height, and α is the wind speed profile index.

[0032] Consider the impact of fluctuating wind vibration responses in the along-wind and across-wind directions on the wind deviation process:

[0033] ;

[0034] Where n is the pulsation frequency, is the fluctuating wind power spectrum along the wind direction, σ u is the root variance of the fluctuating wind speed along the wind direction, is the dimensionless frequency, , is the longitudinal turbulence integral scale.

[0035] ;

[0036] In the formula, u * is the surface friction velocity. is the von Karman constant, and z0 is a parameter reflecting the roughness of the surface.

[0037] Across-wind fluctuating wind power spectrum S v (n) Use the following expression:

[0038] ;

[0039] In the formula, is the dimensionless frequency, x = n·z / U(z), is the root variance of the fluctuating wind speed in the crosswind direction.

[0040] ;

[0041] In the formula, u * is the surface friction velocity.

[0042] The AR linear filtering method is used to simulate the random pulsating wind speed field in the along and across wind directions at a spatial point, and then the established average wind speed field is superimposed to obtain the actual instantaneous wind speed field of the local area for the subsequent calculation of wind loads.

[0043] Preferably, the method for solving the problem by finite element software in step 4 is as follows:

[0044] Step 41, the windage is described by the following basic motion equation of transient dynamics:

[0045] [ M ]{ u ¨ } + [ C ]{ u ˙ } + [ K ]{ u } = { F ( t )} ;

[0046] Where [M] is the mass matrix of the structure, [C] is the damping matrix of the structure, and [K] is the stiffness matrix of the structure. is the node displacement array, is the node velocity array, is the node acceleration array, is the node load array.

[0047] Step 42: Convert the instantaneous wind load into the corresponding node load array , applied to the corresponding nodes of the finite element model. The Newmark method in the time domain step-by-step integration method in ANSYS software is used to solve the corresponding node displacement array of the suspension insulator string. , and then convert it into the corresponding windage angle based on the geometric relationship.

[0048] Preferably, the method for obtaining the deadweight load in step 3 is as follows:

[0049] The self-weight load of the suspension insulator string model is achieved by setting the linear density of the real material and applying the gravity field.

[0050] The process of applying the conductor's own weight load is called form-finding, and the initial form-finding is performed using the suspension cable analysis method.

[0051] Preferably, the method for constructing a finite element model of a suspension insulator string and its connected structure according to the structural parameters of the line in step 2 is as follows:

[0052] Step 21, constructing and constraining a finite element model of a suspension insulator string according to the structural parameters of the line.

[0053] According to the different mechanical properties of the suspension insulator string during wind deflection, different types of units are selected for simulation, which are divided into simulation of porcelain / glass insulator string and simulation of composite insulator string.

[0054] For the simulation of porcelain / glass insulator string, rigid beam units are used to simulate the monolithic insulators, and the connection between different units is hinged.

[0055] The composite insulator string is simulated using ordinary beam elements, and is divided into multiple beam elements according to the actual length of the composite insulator string. The connection between different elements is rigid connection.

[0056] The upper end of the suspension insulator string is directly hinged.

[0057] Step 22, constructing and constraining a conductor finite element model according to the structural parameters of the line.

[0058] Rod elements are used to simulate the tensile wires, and the connection between different rod elements is rigid connection.

[0059] The end hanging points of the conductor are usually located on the tension towers on both sides of the tension section. The conductor is connected to them through tension insulator strings. The rotation effect of the insulator string and the hanging points, as well as the deformation of the conductor itself, only constrain the degrees of freedom of the node in the three translational directions and the torsional degree of freedom around the axis of the conductor.

[0060] Preferably, the structural parameters of the line include the insulator string model and its corresponding parameters, the conductor model and its corresponding parameters, the adjacent spans, the height difference, the local average altitude, and the meteorological parameters include the local temperature, the conductor / suspension insulator string annular equivalent ice thickness, ice type, and instantaneous wind speed.

[0061] Another object of the present invention is to provide a high-altitude ice-covered suspension insulator string windage determination system, which is used to implement the high-altitude ice-covered suspension insulator string windage determination method, including an input unit, a finite element model building unit, a deadweight load application unit, an instantaneous wind load application unit, and a solution unit, wherein:

[0062] The input unit is used to obtain structural parameters and meteorological parameters of the line.

[0063] The finite element model building unit is used to build a finite element model of a suspension insulator string and its connected structure according to the structural parameters of the line.

[0064] The self-weight load applying unit is used to apply the self-weight load to the finite element model according to the structural parameters of the line.

[0065] The instantaneous wind load application unit is used to determine the simulation of the wind speed field according to the meteorological parameters. The drag coefficient is introduced into the simulation of the wind speed field. At the same time, the air density is corrected according to the influence of the altitude and the ambient temperature on the air characteristics to obtain the instantaneous wind load, and then the instantaneous wind load is applied to the finite element model.

[0066] The solving unit is used to solve the finite element model, deadweight load and instantaneous wind load through finite element software to obtain the corresponding node displacement array of the suspension insulator string, and then convert the node displacement array into the corresponding wind deflection angle according to the geometric relationship.

[0067] Another object of the present invention is to provide an electronic device, comprising: at least one processor, at least one memory and a communication interface. The processor, memory and communication interface communicate with each other. The memory stores program instructions executable by the processor, and the processor calls the program instructions to execute the method for determining windage deviation of ice-covered suspension insulator strings in high altitude areas.

[0068] Compared with the prior art, the present invention has the following beneficial effects:

[0069] Under the premise of fully considering the influence of line icing on the two-sidedness of wind deflection, the wind load is accurately applied and the wind deflection angle is accurately solved by correcting the air characteristic parameters in high altitude areas and introducing the aerodynamic coefficient, so that the wind deflection accuracy is high. At the same time, the calculation process is standardized and universalized, which greatly improves the applicability of the wind deflection calculation method in high altitude areas. The results can provide a reference for the design of transmission lines and the prevention and control of wind and snow disasters in plateau areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 This is a rigid body static calculation model.

[0071] Figure 2 Schematic diagram of instantaneous wind load acting on the equivalent annular ice-covered cross section.

[0072] Figure 3 The structural parameters of the line are shown in Figure 2.

[0073] Figure 4 is the finite element model and its constraints (after wire form-finding).

[0074] Figure 5This is the wind speed simulation result within 30 minutes at the midpoint of the first gear L1.

[0075] Figure 6 Wind load is applied to the finite element model at the initial moment. DETAILED DESCRIPTION

[0076] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0077] Example

[0078] At present, the calculation of wind deflection of suspension insulator strings is mostly based on the rigid straight rod model, which combines the static balance principle to calculate the wind deflection angle. This is also the method recommended in the design specifications of overhead transmission lines in my country, hereinafter referred to as the rigid static method.

[0079] like Figure 1 As shown in the figure, the rigid body static method regards the suspension insulator string as a rigid rod with uniform mass distribution. The connection between its upper end and the cross arm is hinged, and its own gravity G j and the horizontal wind load F j Acting at its centroid (1 / 2 rod length), the wire gravity and G d and the wind load F acting on the conductor in the horizontal direction d The stabilizing effect is at its lower end.

[0080] According to the moment balance principle of statics, taking the moment at point O, the calculation formula for the wind deflection angle θ can be obtained as follows:

[0081] ;

[0082] The rigid body static method model is simple and intuitive, but the factors considered are relatively single, and the dynamic process of the wind deflection of the suspension insulator string is not taken into account. In actual line projects, the wind field has certain pulsating characteristics, which in turn produces a certain dynamic amplification effect on the wind deflection of the suspension insulator. Therefore, the wind deflection calculation results of the rigid body static method are often too small. In view of this, the present embodiment provides a method for determining the wind deflection of an ice-covered suspension insulator string in high-altitude areas. By constructing a finite element model that conforms to the mechanical characteristics of the suspension insulator string and the overhead conductor, correcting the air characteristic parameters in the plateau area, and introducing the aerodynamic coefficient of the windward surface of the ice-covered wire, etc., the accurate calculation of the wind deflection angle under the real wind field and line icing conditions in high-altitude areas is achieved. Specifically, the following steps are included:

[0083] Step 1: Obtain the structural parameters and meteorological parameters of the line.

[0084] In another embodiment, the structural parameters of the line include the insulator string model and its corresponding parameters, the conductor model and its corresponding parameters, adjacent spans, height differences, local average altitude, etc., and the meteorological parameters include local temperature, conductor / suspension insulator string annular equivalent ice thickness, ice type, instantaneous wind speed, etc.

[0085] Step 2: construct a finite element model of the suspension insulator string and its connected structure according to the structural parameters of the line.

[0086] In another embodiment, the method for constructing a finite element model of a suspension insulator string and its connected structure according to the structural parameters of the line in step 2 is as follows:

[0087] Step 21: Construction and constraints of finite element model of suspension insulator string

[0088] According to the different mechanical characteristics of the suspension insulator string during wind deflection, different types of units are selected for simulation.

[0089] For porcelain / glass insulator strings: Each insulator hardly deforms during wind deflection, so it is assumed to be a rigid body. The wind deflection bending is caused by the ball joint connection between the steel legs and steel caps between adjacent insulators. Therefore, a rigid beam unit is used to simulate a single insulator, and the connection between different units is hinged.

[0090] For composite insulator strings: Wind deflection bending is due to the low stiffness of its own material, so ordinary beam units are used for simulation, and the strings are divided into multiple beam units according to the actual length of the composite insulators. The connection between different units is rigid connection.

[0091] In actual projects, the upper end of the suspension insulator string is often connected to the transmission tower with the help of a U-shaped ring, which can rotate relatively freely, and the windage calculation process does not involve the mechanical calculation of the transmission tower. Therefore, the upper end of the suspension insulator string is directly hinged, that is, the degrees of freedom of the node in the three translational directions are constrained, and the degrees of freedom in the three rotational directions are released.

[0092] Step 22: Wire finite element model construction and constraints

[0093] As a typical flexible cable structure, the mechanical model of overhead transmission lines is mainly based on the following assumptions: the cable material conforms to Hooke's law; the cable can only be subjected to tension but not compression. Therefore, rod units are used to simulate the tensile conductor, and the connection between different rod units is rigid connection.

[0094] The end hanging points of the conductor are usually located on the tension towers on both sides of the tension section (including multiple straight sections). The conductor is connected to the tension towers through tension insulator strings. Due to the rotation effect of the insulator strings and the hanging points, as well as the deformation of the conductor itself, only the degrees of freedom in the three translational directions of the node and the torsional degrees of freedom around the axis of the conductor are constrained.

[0095] Step 3: Apply deadweight load to the finite element model according to the structural parameters of the line. Determine the simulation of the wind speed field according to the meteorological parameters, introduce the drag coefficient into the simulation of the wind speed field, and correct the air density according to the influence of altitude and ambient temperature on air characteristics to obtain the instantaneous wind load, and then apply the instantaneous wind load to the finite element model.

[0096] Step 31, self-weight load.

[0097] The self-weight load of the suspension insulator string model is achieved by setting the linear density of the real material and applying the gravity field.

[0098] The process of applying the deadweight load of the conductor is called form-finding, which is a step that must be performed before any static and dynamic analysis of the cable-type structure. Only through form-finding can the initial position and stress distribution of the conductor before wind deflection be accurately obtained. In another embodiment, the cable analysis method is used for initial form-finding, and the specific form-finding steps are as follows:

[0099] A. Create a geometric model at the chord position determined by the span and height difference, set the corresponding real constants according to the actual conductor material parameters, and set a smaller initial strain to obtain solution stability.

[0100] B. After meshing the conductor geometry model, convert it into the corresponding finite element model, apply the vertical gravity field load and solve it. Update the conductor geometry by updating the finite element model until the convergence condition is met: the horizontal tension component of the conductor is equal to 38% of the rated breaking force, and obtain the initial position and stress distribution of the conductor under the deadweight load.

[0101] In another embodiment, the instantaneous wind load in step 3 is obtained as follows:

[0102] Step 32: Apply wind load.

[0103] Step 321, simulation of wind speed field.

[0104] The statistical analysis results of a large amount of measured wind speed data show that the instantaneous wind field in the natural environment can be regarded as the superposition of the time-domain average wind field and the instantaneous pulsating wind field. The present invention uses the following method to simulate the actual wind speed field:

[0105] The average wind speed profile of the atmospheric boundary layer within a certain height range is described by the following exponential law:

[0106] ;

[0107] In the formula, is the average wind speed at a height z above the ground, U r is the reference height (z r ) at the average wind speed, zr is the reference height, usually 10m, α is the wind speed profile index, different surface types correspond to different values, the present invention adopts the values ​​in the Code for Loads on Building Structures GB5009-2012 of my country: there are 4 categories: offshore, rural, urban and large city center, and the indexes are 0.12, 0.15, 0.22 and 0.30 respectively.

[0108] The pulsating wind field is the turbulent part of the wind field. Its intensity varies randomly with time and space, and its period is short, thus generating pulsating force on the structure. In this embodiment, the influence of the pulsating wind vibration response along the wind and across the wind on the wind deviation process is mainly considered. The pulsating wind power spectrum S along the wind u (z,n) The empirical formula of wind spectrum proposed by Theodore von Karman in 1948 based on the assumption of turbulence isotropy was used, and the expression improved by Harris later was:

[0109] ;

[0110] Where n is the pulsation frequency, is the fluctuating wind power spectrum along the wind direction, σ u is the root variance of the fluctuating wind speed along the wind direction, is the dimensionless frequency, , is the longitudinal turbulence integral scale, and is usually: .

[0111] ;

[0112] In the formula, u * is the surface friction velocity. is the von Karman constant, which is generally taken as 0.4. z0 is a parameter reflecting the roughness of the surface, which is given by experience, such as 0.01~0.05m in open grassland, 0.1~0.5m in urban suburbs, and 1~5m in the city center with dense buildings.

[0113] Across-wind fluctuating wind power spectrum S v (n) Use the following empirical expression:

[0114] ;

[0115] In the formula, is the dimensionless frequency, x = n·z / U(z), is the root variance of the fluctuating wind speed in the crosswind direction.

[0116] ;

[0117] In the formula, u * is the surface friction velocity

[0118] The AR linear filtering method is used to simulate the random pulsating wind speed field in the along and across wind directions at a spatial point, and then the established average wind speed field is superimposed to obtain the actual instantaneous wind speed field of the local area for subsequent calculation of wind loads.

[0119] Step 322, calculation of wind load:

[0120] The instantaneous wind load acting on the equivalent annular ice-covered cross section is as follows: Figure 2 As shown, Figure 2 U is the horizontal average wind speed. Considering the influence of fluctuating wind speed, the instantaneous wind speed in the horizontal direction (X axis) is U+u (u is the fluctuating wind speed in the horizontal direction), and the instantaneous fluctuating wind speed in the vertical direction (Y axis) is v. Therefore, the actual instantaneous incoming wind speed on the structure is V ( ), and the angle of V relative to the average wind speed direction is δ. d is the instantaneous wind resistance to the ice-covered section; h is the thickness of the equivalent annular ice

[0121] Based on the Bernoulli equation and the quasi-steady assumption, the instantaneous wind load component of the ice-covered section is calculated with the help of the resistance coefficient c d And instantaneous wind speed V is calculated:

[0122] ;

[0123] In the formula, F d is the instantaneous wind resistance to the ice-covered section, ρ is the air density under ice-covered conditions, V is the instantaneous wind speed, h is the equivalent annular ice thickness, c d (V,h) is the drag coefficient, which is a function of the instantaneous wind speed V and the equivalent annular ice thickness h, and can be solved using the following expression:

[0124] ;

[0125] In the formula, The symbol for scientific notation.

[0126] Taking into account the influence of altitude and ambient temperature on air characteristics, the air density ρ is corrected using the following formula:

[0127] ;

[0128] Where He is the local average altitude, T a is the average temperature under local icing conditions.

[0129] The instantaneous wind load is converted to the global coordinate system XOY:

[0130] ;

[0131] In the formula, is the instantaneous wind load in the horizontal direction, is the instantaneous wind load in the vertical direction, ρ is the air density under icing conditions, h is the equivalent annular ice thickness, U is the horizontal average wind speed, u is the horizontal pulsating wind speed, c d (V,h) is the drag coefficient, V is the instantaneous wind speed, and v is the instantaneous pulsating wind speed in the vertical direction.

[0132] The formula for instantaneous wind load is:

[0133]

[0134] In the formula, is the instantaneous wind load in the horizontal direction, is the instantaneous wind load in the vertical direction, He is the local average altitude, T a is the average temperature under local icing conditions, h is the equivalent annular ice thickness, U is the horizontal average wind speed, u is the horizontal fluctuating wind speed, v is the instantaneous fluctuating wind speed in the vertical direction, V is the instantaneous wind speed, The symbol for scientific notation.

[0135] Step 4, solve and calculate the wind deviation.

[0136] According to the finite element model, the deadweight load and the instantaneous wind load are solved by the finite element software to obtain the corresponding node displacement array of the suspension insulator string, and then the node displacement array is converted into the corresponding wind deflection angle according to the geometric relationship.

[0137] Step 41, windage in actual engineering is a typical nonlinear dynamics problem, and windage is described by the following basic motion equation of transient dynamics:

[0138] [ M ]{ u ¨ } + [ C ]{ u ˙ } + [ K ]{ u } = { F ( t )} ;

[0139] Where [M] is the mass matrix of the structure, [C] is the damping matrix of the structure, and [K] is the stiffness matrix of the structure. is the node displacement array, is the node velocity array, is the node acceleration array, is the node load array.

[0140] Step 42, convert the node wind load obtained according to formula (10) into the corresponding node load array , applied to the corresponding nodes of the finite element model. The Newmark method in the time domain step-by-step integration method in ANSYS software is used to solve the corresponding node displacement array of the suspension insulator string. , and then convert it into the corresponding windage angle based on the geometric relationship.

[0141] Due to the nonlinearity of the structure itself and the complexity of the actual wind load, it is difficult to obtain the analytical solution of the structure. Therefore, the large-scale commercial finite element software ANSYS is used to obtain the numerical solution of the above motion equations.

[0142] Step 421, first of all, the basic finite element model is constructed, and the corresponding structural mass matrix [M] and stiffness matrix [K] can be automatically generated in the software.

[0143] In step 422, the damping matrix of the structure is calculated using the Rayleigh damping model:

[0144] [ C ] = α [ M ] + β [ K ] ;

[0145] Where: α and β are the mass damping coefficient and stiffness damping coefficient respectively, which can be calculated by the vibration damping ratio:

[0146] ;

[0147] Where: w1 and w2 are the first and second order natural frequencies of the structure, respectively, which can be obtained through modal analysis or testing of the structure; is a constant damping ratio, and the recommended values ​​are as follows: for un-iced structures Take 5% for ice-covered structures. Take 2%.

[0148] Step 423, convert the instantaneous wind load obtained in step 3 into the corresponding node load array , applied to the corresponding nodes of the finite element model.

[0149] Step 424, using the Newmark method in the time domain stepwise integration method in the ANSYS software to solve, obtain the corresponding node displacement array of the suspension insulator string , and then convert it into the corresponding windage angle based on the geometric relationship.

[0150] In another embodiment, a high-altitude ice-covered suspension insulator string windage determination system is provided, which is used to implement the high-altitude ice-covered suspension insulator string windage determination method, including an input unit, a finite element model building unit, a deadweight load application unit, an instantaneous wind load application unit, and a solution unit, wherein:

[0151] The input unit is used to obtain structural parameters and meteorological parameters of the line.

[0152] The finite element model building unit is used to build a finite element model of a suspension insulator string and its connected structure according to the structural parameters of the line.

[0153] The self-weight load applying unit is used to apply the self-weight load to the finite element model according to the structural parameters of the line.

[0154] The instantaneous wind load application unit is used to determine the simulation of the wind speed field according to the meteorological parameters. The drag coefficient is introduced into the simulation of the wind speed field. At the same time, the air density is corrected according to the influence of the altitude and the ambient temperature on the air characteristics to obtain the instantaneous wind load, and then the instantaneous wind load is applied to the finite element model.

[0155] The solving unit is used to solve the finite element model, deadweight load and instantaneous wind load through finite element software to obtain the corresponding node displacement array of the suspension insulator string, and then convert the node displacement array into the corresponding wind deflection angle according to the geometric relationship.

[0156] In another embodiment, an electronic device is provided, comprising: at least one processor, at least one memory and a communication interface. The processor, the memory and the communication interface communicate with each other. The memory stores program instructions executable by the processor, and the processor calls the program instructions to execute the method for determining windage deviation of ice-covered suspension insulator strings in high altitude areas.

[0157] simulation

[0158] Taking one phase of a 500kV overhead transmission line tension section (two straight sections) in Tibet, my country as an example, the feasibility of the wind deviation calculation method proposed in the present invention is introduced.

[0159] S1. Obtain the structural parameters and meteorological parameters of the line as follows Figure 3 , as shown in Table 1.

[0160] Table 1 Line structure and meteorological parameters

[0161] Parameter name value Parameter name value <![CDATA[L1(m)]]> 345 <![CDATA[H1(m)]]> 20 <![CDATA[L2(m)]]> 500 <![CDATA[H2(m)]]> -20 Lead wire model 4×LGJ-300 / 40 Insulator string model FXBW-500 / 160 Average wind speed at reference height 10m (m / s) 20 Equivalent annular ice thickness of insulator string (mm) 20 Conductor equivalent annular ice thickness (mm) 20 Ice type Mixed

[0162] S2. Construct a finite element model of the suspension insulator string and its connected structures.

[0163] According to the above parameters, the finite element model of one phase of the tension section (two straight sections) and its constraints are constructed as follows: Figure 4 shown.

[0164] S3. Apply load.

[0165] The AR linear filtering method (AR model order is 5) is used to simulate the random pulsating wind speed field in the along-wind and across-wind directions at different locations of the structure, and then the average wind speed field is superimposed to simulate the instantaneous wind speed of nodes at different locations. Figure 5 The wind speed simulation results within 30 minutes at the midpoint of the first gear L1 are shown.

[0166] The wind load applied to the finite element model at the initial moment is as follows Figure 6 shown.

[0167] S4. Calculation of wind deviation.

[0168] Modal analysis shows that the first two structural natural frequencies are 0.144520 Hz and 0.200715 Hz, and the constant damping ratio under icing conditions is Taking 2%, the mass damping coefficient α and stiffness damping coefficient β in the Rayleigh damping model can be determined to be 0.0336 and 1.1586 respectively by the vibration modal damping ratio calculation formula. The corresponding damping matrix is ​​constructed and solved by the Newmark method, and the maximum wind deflection angle is 33.1937°.

[0169] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for determining windage deviation of ice-covered suspension insulator strings in high altitude areas, characterized in that: The following steps are involved: Step 1, obtaining the structural parameters and meteorological parameters of the line; Step 2, constructing a finite element model of the suspension insulator string and its connected structure according to the structural parameters of the line; Step 3: Apply deadweight load to the finite element model according to the structural parameters of the line; determine the simulation of the wind speed field according to the meteorological parameters, introduce the drag coefficient into the simulation of the wind speed field, and correct the air density according to the influence of the altitude and ambient temperature on the air characteristics to obtain the instantaneous wind load, and then apply the instantaneous wind load to the finite element model; Step 4, according to the finite element model, the deadweight load and the instantaneous wind load are solved by the finite element software to obtain the corresponding node displacement array of the suspension insulator string, and then the node displacement array is converted into the corresponding wind deflection angle according to the geometric relationship.

2. The method for determining windage deviation of ice-covered suspension insulator strings in high altitude areas according to claim 1, characterized in that: The formula for the instantaneous wind load in step 3 is: In the formula, is the instantaneous wind load in the horizontal direction, is the instantaneous wind load in the vertical direction, He is the local average altitude, T a is the average temperature under local icing conditions, h is the equivalent annular ice thickness, U is the horizontal average wind speed, u is the horizontal fluctuating wind speed, v is the instantaneous fluctuating wind speed in the vertical direction, V is the instantaneous wind speed, The symbol for scientific notation.

3. The method for determining windage deviation of ice-covered suspension insulator strings in high altitude areas according to claim 2, characterized in that: The instantaneous wind load in step 3 is obtained as follows: Step 321, in the simulation of the wind speed field, the AR linear filtering method is used to simulate the random pulsating wind speed field in the along-wind and across-wind directions at the spatial point, and then the average wind speed field is superimposed to obtain the actual instantaneous wind speed field of the local area; Step 322, calculation of wind load: The instantaneous wind load component on the ice-covered section is calculated with the help of the drag coefficient c d And instantaneous wind speed V is calculated: ； In the formula, F d is the instantaneous wind resistance to the ice-covered section, ρ is the air density under ice-covered conditions, V is the instantaneous wind speed, h is the equivalent annular ice thickness, c d (V,h) is the drag coefficient; ； Taking into account the influence of altitude and ambient temperature on air characteristics, the air density ρ is corrected using the following formula: ； Where He is the local average altitude, T a is the average temperature under local icing conditions; The instantaneous wind load is converted to the global coordinate system XOY: ； In the formula, is the instantaneous wind load in the horizontal direction, is the instantaneous wind load in the vertical direction, ρ is the air density under icing conditions, h is the equivalent annular ice thickness, U is the horizontal average wind speed, u is the horizontal pulsating wind speed, c d (V,h) is the drag coefficient, V is the instantaneous wind speed, and v is the instantaneous pulsating wind speed in the vertical direction.

4. The method for determining windage deviation of ice-covered suspension insulator strings in high altitude areas according to claim 3 is characterized in that: The simulation method of the wind speed field in step 321 is as follows: The average wind speed profile of the atmospheric boundary layer within a certain height range is described by the following exponential law: ； In the formula, is the average wind speed at a height z above the ground, U r is the reference height (z r ) at the average wind speed, z r is the reference height, α is the wind speed profile index; Consider the impact of fluctuating wind vibration responses in the along-wind and across-wind directions on the wind deviation process: ； Where n is the pulsation frequency, is the fluctuating wind power spectrum along the wind direction, σ u is the root variance of the fluctuating wind speed along the wind direction, is the dimensionless frequency, , is the longitudinal turbulence integral scale; ； In the formula, u * is the surface friction velocity; is the von Karman constant, z0 is a parameter reflecting the roughness of the surface; Across-wind fluctuating wind power spectrum S v (n) Use the following expression: ； In the formula, is the dimensionless frequency, x = n·z / U(z), is the root variance of the fluctuating wind speed in the crosswind direction; ； In the formula, u * is the surface friction velocity; The AR linear filtering method is used to simulate the random pulsating wind speed field in the along and across wind directions at a spatial point, and then the established average wind speed field is superimposed to obtain the actual instantaneous wind speed field of the local area for the subsequent calculation of wind loads.

5. The method for determining windage deviation of ice-covered suspension insulator strings in high altitude areas according to claim 4, characterized in that: The method for solving the problem using finite element software in step 4 is as follows: Step 41, the windage is described by the following basic motion equation of transient dynamics: ； Where [M] is the mass matrix of the structure, [C] is the damping matrix of the structure, and [K] is the stiffness matrix of the structure. is the node displacement array, is the node velocity array, is the node acceleration array, is the node load array; Step 42: Convert the instantaneous wind load into the corresponding node load array , applied to the corresponding nodes of the finite element model; the Newmark method in the time domain step-by-step integration method in ANSYS software is used to solve and obtain the corresponding node displacement array of the suspension insulator string , and then convert it into the corresponding windage angle based on the geometric relationship.

6. The method for determining windage deviation of ice-covered suspension insulator strings in high altitude areas according to claim 5, characterized in that: The self-weight load in step 3 is obtained as follows: The self-weight load of the suspension insulator string model is realized by setting the linear density of the real material and applying the gravity field; The process of applying the conductor's own weight load is called form-finding, and the initial form-finding is performed using the suspension cable analysis method.

7. The method for determining windage deviation of ice-covered suspension insulator strings in high altitude areas according to claim 6, characterized in that: The method for constructing the finite element model of the suspension insulator string and its connected structure according to the structural parameters of the line in step 2 is as follows: Step 21, constructing and constraining a finite element model of a suspension insulator string according to the structural parameters of the line; According to the different mechanical characteristics of the suspension insulator string during wind deflection, different types of units are selected for simulation, including simulation of porcelain / glass insulator string and simulation of composite insulator string; For the simulation of porcelain / glass insulator string, rigid beam units are used to simulate the single-piece insulator, and the connection between different units is hinged; The composite insulator string is simulated using ordinary beam elements, and is divided into multiple beam elements according to the actual length of the composite insulator string. The connection between different elements is rigid connection. The upper end of the suspension insulator string is directly hinged; Step 22, constructing and constraining a conductor finite element model according to the structural parameters of the line; The rod element is used to simulate the tensile wire, and the connection between different rod elements is rigid connection; The end hanging points of the conductor are usually located on the tension towers on both sides of the tension section. The conductor is connected to them through tension insulator strings. The rotation effect of the insulator string and the hanging points, as well as the deformation of the conductor itself, only constrain the degrees of freedom of the node in the three translational directions and the torsional degree of freedom around the axis of the conductor.

8. The method for determining windage deviation of ice-covered suspension insulator strings in high altitude areas according to claim 7, characterized in that: The structural parameters of the line include the insulator string model and its corresponding parameters, the conductor model and its corresponding parameters, the adjacent spans, the height difference, the local average altitude; the meteorological parameters include the local temperature, the annular equivalent ice thickness of the conductor / suspension insulator string, the ice type, and the instantaneous wind speed.

9. A system for determining windage deviation of ice-covered suspension insulator strings in high altitude areas, characterized in that: The method for determining the wind deflection of ice-covered suspension insulator strings in high altitude areas according to claims 1 to 8 comprises an input unit, a finite element model building unit, a deadweight load application unit, an instantaneous wind load application unit, and a solution unit, wherein: The input unit is used to obtain structural parameters and meteorological parameters of the line; The finite element model building unit is used to build a finite element model of the suspension insulator string and its connected structure according to the structural parameters of the line; The deadweight load applying unit is used to apply deadweight load to the finite element model according to the structural parameters of the line; The instantaneous wind load application unit is used to determine the simulation of the wind speed field according to the meteorological parameters, the drag coefficient is introduced into the simulation of the wind speed field, and the air density is corrected according to the influence of the altitude and the ambient temperature on the air characteristics to obtain the instantaneous wind load, and then the instantaneous wind load is applied to the finite element model; The solving unit is used to solve the finite element model, deadweight load and instantaneous wind load through finite element software to obtain the corresponding node displacement array of the suspension insulator string, and then convert the node displacement array into the corresponding wind deflection angle according to the geometric relationship.

10. An electronic device, characterized in that: include: at least one processor, at least one memory, and a communication interface; The processor, memory and communication interface communicate with each other; The memory stores program instructions that can be executed by the processor, and the processor calls the program instructions to execute the method for determining windage deviation of an ice-covered suspension insulator string in high-altitude areas as described in any one of claims 1-8.

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