Composite insulator umbrella skirt structure optimization method

Abstract

The invention provides a composite insulator umbrella skirt structure optimization method. The method comprises the following steps: S1, determining environmental parameters of a target scene where a composite insulator is located; s2, determining the airflow velocity of the composite insulator target scene based on the environmental parameters; s3, constructing a finite element simulation model of the composite insulator, and determining the airflow velocity in the finite element simulation model for simulation; s4, determining the movement speed of water drops in the simulation airflow, and determining the number of the water drops colliding with the surface of the insulator based on the movement speed of the water drops; s5, determining a water drop collision coefficient of the composite insulator based on the number of water drops colliding with the surface of the insulator; and S6, changing the structural parameters and environmental parameters of the composite insulator, repeating the steps S2-S5 until a termination condition is reached, and selecting the structural parameter of the composite insulator corresponding to the minimum water drop collision coefficient as an optimization result.

Description

TECHNICAL FIELD

[0001] The present application relates to a power equipment optimization method, in particular to a composite insulator shed structure optimization method. BACKGROUND

[0002] Composite insulators are widely used due to their light weight and high strength, but their shed structure is more, and the small shed spacing also leads to serious icing flashover problem, especially for some mountainous areas where people are rare, the rapid development of composite insulator icing flashover often leads to large area power and communication interruption, traffic obstruction, and difficulty in repair, resulting in great economic loss and social influence.

[0003] In the prior art, in order to reduce the icing of composite insulators, the hydrophobic coating method is mainly used to solve the problem, but the stability and durability of the hydrophobic coating cannot be guaranteed, therefore, for this, the prior art also proposes to change the structural parameters of the composite insulator, such as increasing the number of sheds of the composite insulator, although the change of the structural parameters can reduce the icing speed, but when the overall structure of the composite insulator is low, the excessive increase of the number of sheds will shorten the icing flashover path, of course, there are other aspects of structural parameter changes, but unreasonable structural parameters will cause other adverse safety results, therefore, how to determine the reasonable structural parameters of the composite insulator becomes a technical problem.

[0004] Therefore, in order to solve the above technical problems, it is urgent to propose a new technical means. SUMMARY

[0005] Therefore, the purpose of the present application is to provide a composite insulator shed structure optimization method, based on the construction of the finite element model of the composite insulator for simulation, the determination of the water droplet collision coefficient, and the selection of the minimum water droplet collision coefficient of the composite insulator structure parameter as the optimal result, so as to effectively reduce the icing speed from the structure.

[0006] The composite insulator shed structure optimization method provided by the present application comprises the following steps:

[0007] S1. Determine the environmental parameters of the target scene where the composite insulator is located;

[0008] S2. Determine the airflow velocity of the target scene of the composite insulator based on the environmental parameters;

[0009] S3. Construct a finite element simulation model of the composite insulator, and simulate in the finite element simulation model with the determined airflow velocity;

[0010] S4. Determine the motion speed of the water droplets in the simulated airflow, and determine the number of water droplets colliding with the surface of the insulator based on the motion speed of the water droplets.

[0011] S5. determining the water droplet collision coefficient of the composite insulator based on the number of water droplets colliding with the surface of the insulator;

[0012] S6. changing the structural parameters of the composite insulator and the environmental parameters, repeating steps S2-S5 until a termination condition is reached, and selecting the structural parameters of the composite insulator corresponding to the minimum water droplet collision coefficient as the optimization result.

[0013] Further, in step S2, the airflow velocity of the target scenario of the composite insulator is determined by the following method:

[0014] The external airflow equation of the composite insulator is constructed:

[0015]

[0016] wherein: p a is the airflow density, v a is the airflow velocity, T represents the environmental temperature, s ij is the stress tensor, E a and H a are the total energy and enthalpy, respectively;

[0017] The finite element method is used to solve equations (1)-(3) to determine the airflow velocity v a of the target scenario of the composite insulator.

[0018] Further, the movement velocity of the water droplet in the simulated airflow is specifically:

[0019]

[0020] S w = p d 2 (4);

[0021] wherein: C D is the water droplet resistance coefficient; m w is the mass of the water droplet; S w is the maximum cross-sectional area of the water droplet; R d is the maximum cross-sectional diameter of the water droplet;

[0022] The airflow velocity v a is substituted into equation (4) to obtain the movement velocity v d of the water droplet.

[0023] Further, the water droplet collision coefficient of the composite insulator is determined based on the number of water droplets colliding with the surface of the insulator, specifically:

[0024] wherein: N xN is the number of water droplets in the projected area of the composite insulator on the windward surface.

[0025] Further, the number N of water droplets in the projected area of the composite insulator on the windward surface is determined by the following method:

[0026] S is the projected area of the composite insulator on the windward surface, and ds is the spacing between water droplets in the airflow;

[0027]

[0028] wherein: MVD is the median volume diameter of the water droplets, and p d represents the water droplet density, and w is the liquid water content in the airflow.

[0029] Advantages of the present application: through the present application, based on the simulation by constructing the finite element model of the composite insulator, the water droplet collision coefficient is determined, and the structure parameters of the composite insulator with the minimum water droplet collision coefficient are selected as the optimal result, so that the icing speed can be effectively reduced from the structure. BRIEF DESCRIPTION OF DRAWINGS

[0030] The present application will be further described below in combination with the drawings and examples:

[0031] Figure 1 The flowchart of the present application.

[0032] Figure 2 The collision coefficient variation curve of the specific example of the present application.

[0033] Figure 3 The water droplet collision coefficient variation curve of different umbrella skirt diameters of the present application.

[0034] Figure 4 The water droplet collision variation curve of different umbrella skirt inclination angles of the present application.

[0035] Figure 5 The water droplet array diagram of the composite insulator of the present application. DETAILED DESCRIPTION

[0036] The present application will be further described below in combination with the drawings and examples:

[0037] The present application provides a composite insulator umbrella skirt structure optimization method, comprising the following steps:

[0038] S1. Determine the environmental parameters of the target scene where the composite insulator is located; wherein the environmental parameters include environmental temperature and wind speed;

[0039] S2. Determine the airflow speed of the target scene of the composite insulator based on the environmental parameters;

[0040] S3. Constructing a finite element simulation model of the composite insulator, and simulating in the finite element simulation model at a determined airflow speed; wherein the finite element simulation model is established by using existing software, such as Fluent software;

[0041] S4. Determining the movement speed of water droplets in the simulated airflow, and determining the number of water droplets colliding with the surface of the insulator based on the movement speed of the water droplets;

[0042] S5. Determining the water droplet collision coefficient of the composite insulator based on the number of water droplets colliding with the surface of the insulator;

[0043] S6. Changing the structural parameters and environmental parameters of the composite insulator, repeating steps S2-S5 until a termination condition is reached, and selecting the structural parameters of the composite insulator corresponding to the minimum water droplet collision coefficient as the optimization result. The structural parameters of the composite insulator include the umbrella skirt inclination angle (including the upper inclination angle and the lower inclination angle), the umbrella skirt diameter, and the umbrella skirt spacing. By simulating under different structural parameters and different environmental parameters, the structural parameters with the minimum water droplet collision coefficient are selected as the optimal result. Through the present application, the water droplet collision coefficient is determined based on the simulation of the finite element model of the composite insulator, and the structural parameters of the composite insulator with the minimum water droplet collision coefficient are selected as the optimal result, thereby effectively reducing the icing speed from the structure.

[0044] In this embodiment, in step S2, the airflow speed of the target scenario of the composite insulator is determined by the following method:

[0045] The external airflow equation of the composite insulator is constructed:

[0046]

[0047] Wherein: p a is the airflow density, v a is the airflow speed, T represents the environmental temperature, s ij is the stress tensor, E a and H a are the total energy and enthalpy, respectively;

[0048] The finite element method is used to solve equations (1)-(3) to determine the airflow speed v a of the target scenario of the composite insulator. Through the above, the airflow speed under different wind speed conditions can be determined, providing data support for accurately determining the movement speed of water droplets subsequently.

[0049] In this embodiment, the movement speed of water droplets in the simulated airflow is determined as follows:

[0050]

[0051] S w =πR d 2 (4);

[0052] Where: C D It is the water droplet resistance coefficient; m w S is the mass of the water droplet; w R is the maximum cross-sectional area of ​​the water droplet; d The maximum cross-sectional diameter of the water droplet;

[0053] airflow velocity v a Substituting into formula (4), we can obtain the velocity v of the water droplet. d Once the speed of the water droplets is determined, their trajectory and position can be determined (this process is existing technology). Finally, it is determined whether the water droplets in the airflow collide with the surface of the composite insulator, and the number of collisions between the water droplets and the composite insulator is counted.

[0054] In this embodiment, the water droplet collision coefficient of the composite insulator is determined based on the number of water droplets colliding with the insulator surface as follows:

[0055] Where: N x The number of water droplets that collide with the surface of the insulator; N is the number of water droplets in the projected area of ​​the composite insulator on the windward side.

[0056] The number N of water droplets N within the projected area of ​​the composite insulator on the windward side is determined by the following method:

[0057] S is the projected area of ​​the composite insulator on the windward side, and ds is the distance between water droplets in the airflow; S and ds are as follows: Figure 5 As shown, in the simulation, the water droplets are arranged in an array;

[0058]

[0059] Where: MVD is the median volume diameter of the water droplet, ρ d denoted by , where is the density of the water droplets, and w is the liquid water content in the airflow.

[0060] The following is a specific example to illustrate this:

[0061] like Figure 2 As shown, Figure 2 The curves show the variation of the water droplet collision coefficient under different wind speeds. Figure 3 and Figure 4 The curves showing the variation of the water droplet collision coefficient under different umbrella skirt diameters and inclination angles are shown, taking the inclination angle as an example:

[0062] Assuming that the variable range of the inclination angle of the composite insulator shed is θ1=5°-20°, and the corresponding composite insulator runs in the low winter ice environment of the common water droplet median volume diameter MVD=40 μm-50 μm, and the average wind speed is 8 m / s, then the optimal inclination angle of the composite insulator shed is θ1=20°. If MVD=10 μm-30 μm, and the average wind speed is 8 m / s, then θ1=5° needs to be selected.

[0063] Finally, it should be pointed out that the above examples 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, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the purpose and scope of the technical solutions of the present application, and they should all be covered in the scope of the claims of the present application.

Claims

1. A method for optimizing the structure of a composite insulator shed, characterized in that: Includes the following steps: S1. Determine the environmental parameters of the target scenario where the composite insulator is located; S2. Determine the airflow velocity in the target scenario for composite insulators based on environmental parameters; S3. Construct a finite element simulation model of the composite insulator and perform simulation to determine the airflow velocity in the finite element simulation model; S4. Determine the velocity of water droplets in the simulated airflow, and determine the number of water droplets that collide with the insulator surface based on the velocity of the water droplets; S5. Determine the water droplet collision coefficient of the composite insulator based on the number of water droplets colliding with the insulator surface; S6. Change the structural parameters and environmental parameters of the composite insulator, repeat steps S2-S5 until the termination condition is met, and select the structural parameters of the composite insulator corresponding to the minimum water droplet collision coefficient as the optimization result.

2. The method for optimizing the composite insulator skirt structure according to claim 1, characterized in that: In step S2, the airflow velocity of the composite insulator target scenario is determined using the following method: Constructing the external airflow equation for composite insulators: Where: ρ a It is the airflow density, v a It represents airflow velocity, T represents ambient temperature, and σ ij It is the stress tensor, E a and H a These are total energy and enthalpy, respectively. The airflow velocity v of the target scenario for the composite insulator is determined by solving equations (1) to (3) using the finite element method. a .

3. The method for optimizing the composite insulator skirt structure according to claim 2, characterized in that: The specific steps to determine the velocity of water droplets in the simulated airflow are as follows: S w =πR d 2 (4); Where: C D It is the water droplet resistance coefficient; m w S is the mass of the water droplet; w R is the maximum cross-sectional area of ​​the water droplet; d The maximum cross-sectional diameter of the water droplet; airflow velocity v a Substituting into formula (4), we can obtain the velocity v of the water droplet. d .

4. The method for optimizing the composite insulator skirt structure according to claim 1, characterized in that: The water droplet collision coefficient of the composite insulator is determined based on the number of water droplets colliding with the insulator surface. Where: N x The number of water droplets that collide with the surface of the insulator; N is the number of water droplets in the projected area of ​​the composite insulator on the windward side.

5. The method for optimizing the composite insulator skirt structure according to claim 4, characterized in that: The number N of water droplets N within the projected area of ​​the composite insulator on the windward side is determined by the following method: S is the projected area of ​​the composite insulator on the windward side, and ds is the distance between water droplets in the airflow. Where: MVD is the median volume diameter of the water droplet, ρ d denoted by , where is the density of the water droplets, and w is the liquid water content in the airflow.

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