Ice jump simulation method for uneven icing of high-altitude large-span power transmission line

Abstract

The invention provides a high-altitude large-span power transmission line non-uniform icing ice jump simulation method, which comprises the following steps: S1, obtaining structural parameters of a target large-span power transmission line in a high-altitude area, taking a vertex of a tower with a smaller height between two towers in a span as a reference point, and establishing a coordinate system by using the reference point; s2, acquiring meteorological parameters, including wind speed, temperature and humidity, at the reference point; s3, ANSYS finite element software is adopted to establish a simulation model of the target large-span power transmission line according to the structural parameters of the target large-span power transmission line, and the power transmission line in the span is divided into a plurality of finite elements; s4, determining the meteorological parameters of each finite element according to the meteorological parameters of the reference point, then determining the icing amount of each finite element, and loading the icing amount of the finite element to the finite element in the simulation model; and S5, simulating deicing in the simulation model, and obtaining ice jump parameters during deicing.

Description

TECHNICAL FIELD

[0001] The application relates to an ice jump simulation method for uneven icing of a high-altitude large-span power transmission line. BACKGROUND

[0002] The high-altitude large-span line generally has the structural characteristics of an ultra-long span and a significant height difference, so that the micro-meteorological environments of different parts of the conductor in the same span are quite different, and meteorological parameters such as wind speed, temperature and humidity change in a gradient along the span direction, thereby causing frequent uneven icing in the same span. Under the condition of uneven icing of the large-span line, the unbalanced tension and the violent jumping movement generated at the moment of ice shedding are extremely easy to cause serious accidents such as conductor interphase short circuit, conductor-ground line collision and fitting fracture, and further cause large-area power failure, thereby posing a great threat to the safe operation of the power grid.

[0003] In the prior art, the icing and ice jump problems of the large-span power transmission line are generally analyzed by using the finite element method, and the influence of uneven icing on the dynamic response of the conductor is ignored based on the assumption of uniform icing of the large-span power transmission line, so that the real mechanical behavior of the large-span line in the ice shedding and jumping process cannot be accurately reflected, and the risk of conductor interphase and conductor-ground line short circuit cannot be effectively evaluated.

[0004] Therefore, in order to solve the above technical problems, a new technical means is urgently needed. SUMMARY

[0005] Therefore, the purpose of the present application is to provide an ice jump simulation method for uneven icing of a high-altitude large-span power transmission line, which can accurately simulate the actual icing scene and obtain accurate ice jump parameters in the ice shedding process, and provide accurate data support for the development of subsequent ice removal measures.

[0006] The application provides an ice jump simulation method for uneven icing of a high-altitude large-span power transmission line, which comprises the following steps:

[0007] S1. Obtain the structure parameters of the target large-span power transmission line in a high-altitude area, and take the top point of the tower with smaller height between two towers in a span as a reference point, and establish a coordinate system based on the reference point;

[0008] S2. Obtain the meteorological parameters at the reference point, including wind speed, temperature and humidity;

[0009] S3. Adopting ANSYS finite element software to establish a simulation model of the target large-span transmission line according to the structural parameters of the target large-span transmission line, and dividing the transmission line in the span into a plurality of finite elements;

[0010] S4. Determining the meteorological parameters of each finite element according to the meteorological parameters of the reference point, then determining the icing amount of each finite element, and loading the icing amount of the finite element on the finite element in the simulation model;

[0011] S5. Simulating ice shedding in the simulation model, and obtaining ice jump parameters when the ice is shed.

[0012] Further, determining the icing amount of each finite element specifically includes:

[0013] ;

[0014] Wherein: represents the icing mass growth of the finite element, represents the collision coefficient of liquid water droplets in the air with the transmission conductor, represents the capture coefficient of liquid water droplets when icing, represents the freezing coefficient, represents the wind speed at the location of the current finite element, represents the liquid water content at the location of the current finite element, and A represents the effective icing cross-sectional area.

[0015] Further, the wind speed of the current finite element is determined according to the following method :

[0016] ; wherein, represents the wind speed at the reference point, represents the wind speed correction coefficient.

[0017] Further, the wind speed correction coefficient is determined by the following method:

[0018] When the tower at the reference point is on the windward slope or leeward slope of the mountain:

[0019] ;

[0020] When the tower at the reference point is on the windward slope or crosswind slope of the mountain:

[0021] ;

[0022] Wherein: ; ;

[0023] ; represents the wind speed correction coefficient of the mountain top

[0024] ; represents the wind speed correction coefficient at the foot of the mountain;

[0025] wherein h represents the elevation of the finite element, H represents the height of the mountain where the reference point tower is located, and k represents a constant coefficient set, represents the height of the wind field, , represents the horizontal distance between the vertical line of the upper vertex and the foot of the mountain.

[0026] Further, the elevation of the finite element is determined by the following method:

[0027] ;

[0028] wherein: is the height difference between the suspension points of the conductor on both sides, is the axial stress of the lowest point of the conductor, is the gravity specific load, s is the span of the conductor, x is the horizontal distance of the current finite element to the reference point, and c is a coefficient related to the climate condition and seasonal condition, and the value is c = 4.45 x 10 -4 .

[0029] Further, the freezing coefficient is determined by the following method :

[0030] ;

[0031] wherein: b S and D are the surface area and diameter of the conductor respectively; T s and T represent the balance temperature and environmental temperature of the icing surface of the conductor respectively; r c is the local recovery coefficient of the surface of the circular conductor; h c is the convective heat transfer coefficient; is the evaporation or sublimation coefficient; is the saturation water vapor pressure of the ice layer surface when the temperature is T, , are the specific heat of ice and air respectively, is the emissivity; is the Stefan-Boltzmann constant.

[0032] Further, the collision coefficient is determined by the following method :

[0033] .

[0034] The beneficial effects of the present application: the structure parameters of the icing power transmission line in the actual working condition are used to construct the corresponding finite element model, and the corresponding icing parameters are determined through the finite elements at different positions, and the corresponding icing mass is determined to simulate, so that the actual icing scene can be accurately simulated, the accurate ice jump parameters are obtained in the ice shedding process, and accurate data support is provided for the development of subsequent deicing measures. BRIEF DESCRIPTION OF DRAWINGS

[0035] The present application will be further described below in conjunction with the drawings and examples:

[0036] Figure 1 The flowchart of the present application.

[0037] Figure 2 The structure diagram of the tower in the mountain of the present application. DETAILED DESCRIPTION

[0038] The present application will be further described below in conjunction with the drawings and examples:

[0039] The present application provides a high-altitude large-span power transmission line uneven icing ice jump simulation method, comprising the following steps:

[0040] S1. Obtain the structure parameters of the target large-span power transmission line in the high-altitude area, and take the top point of the tower with smaller height between the two towers in an interval as the reference point, and establish a coordinate system with the reference point; generally, in a large-span power transmission line interval, two towers are arranged on two mountains respectively, and the middle part forms a larger length of power transmission line, and the structure parameters of the large-span power transmission line specifically include:

[0041] Conductor and ground wire: outer diameter, elastic modulus, cross-sectional area, calculated weight, breaking force, safety factor and operating tension;

[0042] Tower: tower type, nominal height; relative position of two towers (i.e. span + elevation difference), conductor and ground wire suspension point height difference;

[0043] Insulator string: string type, suspension mode, equivalent connection length and elastic modulus;

[0044] Terrain condition: altitude, slope type (windward slope, leeward slope, crosswind slope);

[0045] Modeling in the finite element model according to the above parameters;

[0046] S2. Obtain the meteorological parameters at the reference point, including wind speed, temperature and humidity;

[0047] S3. Adopting ANSYS finite element software to establish a simulation model of the target large-span transmission line according to the structural parameters of the target large-span transmission line, and dividing the transmission line in the span into a plurality of finite elements; in the ANSYS finite element software, BEAM188 element is adopted to simulate the conductor, ground wire and insulator string, and then corresponding meteorological conditions are set in the model; when dividing the finite elements, the MESH tool is used to set the size of the finite elements;

[0048] S4. Determining the meteorological parameters of each finite element according to the meteorological parameters of the reference point, and then determining the ice coating amount of each finite element, and loading the ice coating amount of the finite element on the finite element in the simulation model;

[0049] S5. Simulating ice shedding in the simulation model and obtaining ice jump parameters when the ice is shed. Through the above method, the corresponding finite element model is constructed through the structural parameters of the actual icing transmission line in the actual working condition, and the corresponding icing parameters are determined through the finite elements at different positions, and the corresponding ice coating amount is determined for simulation, so that the actual icing scene can be accurately simulated, and accurate ice jump parameters are obtained in the ice shedding process, which provides accurate data support for the development of subsequent deicing measures

[0050] In this embodiment, the determination of the ice coating amount of each finite element specifically includes:

[0051] ;

[0052] Wherein: represents the ice coating mass growth of the finite element, represents the collision coefficient of the liquid water droplets in the air and the transmission conductor, represents the capture coefficient of the liquid water droplets when icing, which generally takes a value of 1; represents the freezing coefficient, represents the wind speed at the position of the current finite element, represents the liquid water content at the position of the current finite element, and A represents the effective icing cross-sectional area.

[0053] Specifically, the wind speed of the current finite element is determined according to the following method :

[0054] ; wherein, represents the wind speed at the reference point, represents the wind speed correction coefficient.

[0055] The wind speed correction coefficient is determined by the following method:

[0056] When the tower as the reference point is on the windward slope or leeward slope of the mountain:

[0057] ;

[0058] When the tower as the reference point is on the windward slope or the crosswind slope of the mountain:

[0059] ;

[0060] Wherein: ; ;

[0061] ; The wind speed correction factor of the mountain top is represented by

[0062] ; The wind speed correction factor of the mountain foot is represented by

[0063] Wherein: h represents the elevation of the finite element, H represents the height of the mountain where the reference point tower is located, k represents a constant coefficient set, The height of the wind field is represented by , The horizontal distance between the vertical line of the upper vertex and the mountain foot is represented by

[0064] The elevation of the finite element is determined by the following method:

[0065] ;

[0066] Wherein: The height difference between the suspension points on both sides of the conductor is represented by The axial stress of the lowest point of the conductor is represented by The gravity specific load is represented by s, the span of the conductor, x is the horizontal distance of the current finite element to the reference point, c is the coefficient related to the climate condition and the seasonal condition, and the value is c=4.45×10 -4 .

[0067] The freezing coefficient is determined by the following method :

[0068] ;

[0069] Wherein: S b , D respectively represents the surface area and diameter of the conductor; T s and T respectively represent the balance temperature and the environmental temperature of the icing surface of the conductor; r c is the local recovery coefficient of the surface of the circular conductor; h c is the convective heat transfer coefficient; is the evaporation or sublimation coefficient; is the saturated water vapor pressure of the ice layer surface at temperature T, , are the specific heat of ice and air, is the emissivity; The Stefan-Boltzmann constant.

[0070] The collision coefficient is determined by the following method :

[0071] By the above, the different finite element position heights can be determined, the corresponding wind speed conditions can be determined, and the corresponding ice accretion mass of each finite element is different, so that the ice accretion process conforming to the actual working condition is simulated, accurate ice jump data is obtained at the time of ice shedding, and accurate data support is provided for the subsequent ice shedding measures.

[0072] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application, and they should be covered in the scope of the claims of the present application.

Claims

1. A method for simulating ice jump of non-uniform icing of high altitude long span transmission lines, characterized in that: The method comprises the following steps: S1. Obtain the structure parameters of the target long-span transmission line in a high-altitude area, and take the top of the tower with smaller height between two towers in a span as a reference point, and establish a coordinate system with the reference point; S2. Obtain the meteorological parameters at the reference point, including wind speed, temperature, and humidity; S3. Establish a simulation model of the target long-span transmission line according to the structure parameters of the target long-span transmission line by using ANSYS finite element software, and divide the transmission line in the span into a plurality of finite elements; S4. Determine the meteorological parameters of each finite element according to the meteorological parameters of the reference point, then determine the icing amount of each finite element, and load the icing amount of the finite element on the finite element in the simulation model; S5. Simulate ice shedding in the simulation model, and obtain ice jump parameters when the ice is shed.

2. The method of claim 1, wherein the method is characterized by: The determination of the icing amount of each finite element specifically comprises: ； wherein: represents the ice accretion amount of the finite element, represents the collision coefficient of the liquid water droplet in the air with the power transmission conductor, represents the capture coefficient of the liquid water droplet at the time of icing, represents the freezing coefficient, represents the wind speed at the position where the current finite element is located, represents the liquid water content at the position where the current finite element is located, and A represents the effective ice accretion cross-sectional area.

3. The method of claim 2, wherein the method is characterized by: The wind speed of the current finite element is determined according to the following method : ; wherein, represents the wind speed at the reference point, represents the wind speed correction factor.

4. The method of claim 3, wherein the method is characterized by: The wind speed correction coefficient is determined by the following method: When the tower at the reference point is on the windward slope or the leeward slope of the mountain: ； When the tower at the reference point is on the windward slope or the leeward slope of the mountain: ； wherein: ; ; ; represents a wind speed correction factor for a mountain top ; represents the wind speed correction factor at the foot of the mountain; wherein: h represents the altitude of the finite element, H represents the height of the mountain on which the reference point tower is located, k represents a constant coefficient set, represents the height of the wind field, , represents the horizontal distance between the vertical line of the upper vertex and the mountain foot.

5. The method of claim 4, wherein: The altitude of the finite element is determined by the following method: ； Wherein: is the height difference between the suspension points of the conductor, is the axial stress of the lowest point of the conductor, is the gravity specific load, s is the span of the conductor, x is the horizontal distance from the current finite element to the reference point, c is a coefficient related to the climate condition and seasonal condition, and the value is c=4.45×10 -4 .

6. The method of claim 4, wherein: The freezing coefficient is determined by the following method : ； where: S b , D are the surface area and diameter of the wire, respectively; T s and T represent the equilibrium temperature of the iced surface and the ambient temperature, respectively; r c is the local restitution coefficient of the surface of the circular conductor; h c is the convective heat transfer coefficient; is the evaporation or sublimation coefficient; is the saturation water vapor pressure at the surface of the ice layer at temperature T, , are the specific heat of ice and air, respectively, is the emissivity; is the Stefan-Boltzmann constant.

7. The method of claim 2, wherein: The coefficient of restitution is determined by the following method : 。

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