Method for calculating the stress exerted by dust particles on a power transmission line during a sandstorm

Abstract

A method for calculating stress exerted on a power transmission line by dust particles during a sandstorm, comprising the following steps: S1: obtaining a probability alpha of collision between dust particles and the power transmission line during a sandstorm based on a volume occupied by the power transmission line in space; S2: simulating a process of collision between a single dust particle and the power transmission line during a sandstorm based on an elastic collision model and a particle motion equation; S3: obtaining an acting force exerted on the power transmission line by the single dust particle from the simulation of the collision between the single dust particle and the power transmission line; and S4: obtaining a stress exerted on the power transmission line by the dust particles based on the acting force exerted on the power transmission line by the single dust particle, a dust particle mass concentration c, and the probability alpha of collision between the dust particles and the power transmission line.

Description

Technical Field

[0001] This invention relates to the field of power transmission line construction and stringing analysis technology, and in particular to a method for calculating the stress exerted on power transmission lines by dust particles during sandstorms. Background Technology

[0002] Power transmission lines, as the lifeline of national economic construction, safeguard the country's economic development and the safety of people's lives and property. The northwestern desert regions possess abundant wind and solar energy resources. In recent years, to effectively utilize these resources, numerous wind power and photovoltaic power stations have been built. To transmit the electricity from these power stations, a large number of transmission lines need to be erected in the desert areas. During construction, these transmission lines require reasonable design. Because desert regions are prone to sandstorms, the design of transmission lines must comprehensively consider the impact of sand and dust two-phase flow on the transmission lines. Therefore, studying the dynamic behavior of transmission lines during sandstorms is a crucial factor in transmission line design. However, current research only considers the influence of wind loads, neglecting the impact of dust particles on the transmission lines. Summary of the Invention

[0003] In view of this, it is necessary to provide a calculation method for the stress exerted on high-voltage transmission lines by dust particles during sandstorms in desert areas, which can predict the forces acting on transmission lines during sandstorms. This method provides important initial and boundary conditions for the study of the dynamic behavior of transmission lines during sandstorms, making the study of the dynamic behavior of transmission lines during sandstorms more accurate and reasonable. It also provides a reliable and reasonable basis for the construction of transmission lines in desert areas, thereby improving the safety of transmission line construction and power transmission in desert areas.

[0004] A method for calculating the stress exerted on power transmission lines by dust particles during a sandstorm includes the following steps:

[0005] S1: Based on the volume occupied by the power transmission line in space, obtain the probability α of dust particles colliding with the power transmission line during a sandstorm.

[0006] S2: Based on the elastic collision model and particle motion equation, simulate the process of a single dust particle colliding with a power transmission line during a sandstorm.

[0007] S3: Obtain the force F exerted by a single dust particle on a power transmission line from the simulation of the collision between a single dust particle and the power transmission line. d ;

[0008] S4: Based on the force F exerted by a single dust particle on the power transmission line d The stress f exerted by the dust particles on the transmission line is obtained by considering the dust particle mass concentration c and the probability α of the dust particles colliding with the transmission line.

[0009] Preferably, in step S1, the probability α of dust particles colliding with power transmission lines during a sandstorm is the average probability, which is obtained by formula (1), where n is the number of dust particles colliding with power transmission lines per unit volume, and N is the number of dust particles per unit volume.

[0010] α=n / N (1)

[0011] Where N is obtained from formula (2), and n is obtained from formula (3),

[0012] N = c / m (2)

[0013] n = Nπ(R + r) 2 (3)

[0014] In the formula, c is the mass concentration of dust particles during a sandstorm, m is the mass of a single dust particle, R is the radius of the transmission line, and r is the radius of a single dust particle.

[0015] Preferably, in step S2, the elastic collision model of a single dust particle with the transmission line is given by formula (4):

[0016]

[0017] In the formula, F n For normal force, R a R is the equivalent radius, E is the equivalent Young's modulus; where R a E and E are obtained from formula (5) and formula (6) respectively:

[0018]

[0019]

[0020] In the formula, E d and E t The Young's modulus, μ, of a single dust particle and a power transmission line, respectively. d and μ t Let r and R be the Poisson's ratios of a single dust particle and a power transmission line, respectively, and let r and R be the radii of the single dust particle and the power transmission line, respectively. δ n This represents the relative deformation of a single dust particle relative to the power transmission line.

[0021] Preferably, in step S3, F d Obtained from formula (7),

[0022]

[0023] In the formula, m represents the mass of a single dust particle, υ1 and υ2 represent the velocities of a single dust particle before and after impacting the transmission line, respectively, and τ represents the collision time between a single dust particle and the transmission line.

[0024] Preferably, in step S4, the stress f exerted by the dust particles on the transmission line is obtained by formula (8).

[0025]

[0026] In the formula, F d Let α be the force exerted by a single dust particle on the power transmission line, N be the number of dust particles per unit volume, and α be the average probability of a dust particle colliding with the power transmission line.

[0027] Preferably, the surface on which the dust particles exert stress on the transmission line is a rectangular area with a length of 1m and a width of 2R, where R is the radius of the transmission line.

[0028] The method for calculating the stress exerted by dust particles on power transmission lines during sandstorms first obtains the probability α of a collision between a dust particle and a power transmission line based on the volume occupied by the power transmission line in space. Then, it uses the particle motion equation and elastic collision model to simulate the collision process of a single dust particle with the power transmission line, and obtains the force F exerted by a single dust particle on the power transmission line. d Finally, based on the force F exerted by a single dust particle on the transmission line... d This invention proposes a method for predicting the stress exerted by dust particles on power transmission lines by calculating the dust particle mass concentration c and the probability α of dust particles colliding with the transmission line. Compared with existing technologies that only consider the influence of wind load when studying the dynamic behavior of power transmission lines during sandstorms, this invention provides an important initial and boundary value condition for the study of the dynamic behavior of power transmission lines, making the study of the dynamic behavior of power transmission lines during sandstorms more accurate and reasonable. This provides a reliable and reasonable basis for the construction of power transmission lines in desert areas, and improves the safety of power transmission and power transmission in desert areas. Attached Figure Description

[0029] Figure 1 This is a flowchart of the present invention.

[0030] Figure 2 In this embodiment of the invention, the impact velocity of the dust particles is 6 m / s, δ n F n The change of dust particle velocity ν with time t.

[0031] Figure 3 This illustrates the variation of collision time τ with the impact velocity ν of dust particles in this embodiment of the invention.

[0032] Figure 4 F in the embodiments of the present invention d The variation law of impact velocity ν of dust particles.

[0033] Figure 5 In this embodiment of the invention, the dust particle mass concentration c is 2 mg / m³. 3 N = 1.44 × 10 6 pcs / m 3 When f changes with the impact velocity ν of the dust particles.

[0034] Figure 6 This embodiment of the invention shows the variation of f with the radius R of the transmission line when the dust particle radius r is 5 μm and the impact velocity ν of the dust particle is 10 m / s.

[0035] Figure 7 In this embodiment of the invention, when the impact velocity of the dust particles ν is 10 m / s, the radius R of the transmission line is 0.02 m, and the number of dust particles per unit volume N = 1.44 × 10⁻⁶ 6 pcs / m 3 The variation of f with the radius r of dust particles. Detailed Implementation

[0036] The technical solutions and effects of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0037] Please refer to Figure 1 As shown, a method for calculating the stress exerted on power transmission lines by dust particles during a sandstorm includes the following steps:

[0038] S1: Based on the volume occupied by the power transmission line in space, obtain the probability α of dust particles colliding with the power transmission line during a sandstorm.

[0039] S2: Based on the elastic collision model and particle motion equation, simulate the process of a single dust particle colliding with a power transmission line during a sandstorm.

[0040] S3: Obtain the force F exerted by a single dust particle on a power transmission line from the simulation of the collision between a single dust particle and the power transmission line. d ;

[0041] S4: Based on the force F exerted by a single dust particle on the power transmission line d The stress f exerted by the dust particles on the transmission line is obtained by considering the dust particle mass concentration c and the probability α of the dust particles colliding with the transmission line.

[0042] Furthermore, in step S1, the probability α of dust particles colliding with power transmission lines during a sandstorm is the average probability, which is obtained by formula (1), where n is the number of dust particles colliding with power transmission lines per unit volume, and N is the number of dust particles per unit volume.

[0043] α=n / N (1)

[0044] Where N is obtained from formula (2), and n is obtained from formula (3),

[0045] N = c / m (2)

[0046] n = Nπ(R + r) 2 (3)

[0047] In the formula, c is the mass concentration of dust particles during a sandstorm, m is the mass of a single dust particle, R is the radius of the transmission line, and r is the radius of a single dust particle.

[0048] In this embodiment, the dust mass concentration *c* during a sandstorm is a measurable physical quantity or obtained from a sandstorm forecasting model. The dust mass concentration *c* represents the number of dust particles per unit volume. The number of dust particles *N* per unit volume can be obtained from the mass *m* of a single dust particle, obtained using formula (2), where *m* is in kg and *N* is in particles per cubic meter. In this invention, it is assumed that dust particles are uniformly distributed in space. Based on this, the ratio of the number of dust particles *n* colliding with power lines per unit volume to the total number of dust particles *N* per unit volume is defined as the average probability of a dust particle colliding with a power line. This means that *N* is approximately equal to the ratio of the average dust mass concentration *c* obtained from long-term measurements to the mass *m* of a single dust particle.

[0049] In this embodiment, n is determined based on the radius R of the transmission line and the radius r of the dust particles. Specifically:

[0050] First, based on a cylinder with a length of 1m and a radius of R+r, the volume of the particle space region that may collide with the power transmission line is determined, and its volume is π(R+r). 2 ;

[0051] Then, the ratio of the cylinder's volume to a unit volume of 1 cubic meter is determined, and this ratio is π(R+r). 2 ;

[0052] Finally, based on this ratio, the number of dust particles n that collide with the transmission line is determined according to the number of dust particles N per unit volume, i.e., formula (3).

[0053] Furthermore, in step S2, the elastic collision model of a single dust particle with the transmission line is given by formula (4):

[0054]

[0055] In the formula, F n For normal force, R a R is the equivalent radius, E is the equivalent Young's modulus; where R a E and E are obtained from formula (5) and formula (6) respectively:

[0056]

[0057]

[0058] In the formula, E respectively d and E t The Young's modulus of a single dust particle and a power transmission line are 6.2 × 10⁻⁶. 10 and 2×10 11 μ d and μ t The Poisson ratios of a single dust particle and a power transmission line are 0.3 and 0.3, respectively. r and R are the radii of the single dust particle and the power transmission line, respectively, 5 μm and 0.02 m, respectively. δ n This refers to the relative deformation of a single dust particle relative to the power transmission line;

[0059] In this embodiment, the portion of the transmission line impacted by a single dust particle is simplified as a disk with radius R, and the dust particle is simplified as a disk with radius r. Since the volume of a single dust particle is much smaller than the volume of the transmission line, in this invention, it is assumed that the velocity of the disk representing the transmission line remains unchanged during the collision process, and is always 0. The collision between the single dust particle and the transmission line is simplified as a head-on collision.

[0060] Since the Stokes number of the air-dust two-phase flow is relatively small, approximately 0.67, the dust particles can be considered to have good following ability, and the velocity of the dust particles can be approximated by the velocity of the flow field. Here, the Stokes number represents the ratio of particle response time to flow field response time. In the air-dust two-phase flow, the particulate phase is dust, and the flow phase is air. In this invention, when the impact velocity ν of the dust particles is 6 m / s, the obtained δ... n F n The change of dust particle velocity ν with time t is as follows: Figure 2 As shown, the impact velocity ν of the dust particles is the initial incident velocity of the dust particles when they collide with the power transmission line.

[0061] Furthermore, in step S3, F d Obtained from formula (7),

[0062]

[0063] In the formula, m represents the mass of a single dust particle, υ1 and υ2 represent the velocities of the dust particle before and after impacting the transmission line, respectively, and τ represents the collision time between a single dust particle and the transmission line.

[0064] In this embodiment, from Figure 2 It can be seen that as time t changes, the relative deformation δ between the dust particles and the transmission line increases. n The first value of 0 indicates the moment before the dust particles collide with the transmission line, with the corresponding start time being t1 and the corresponding dust particle velocity being υ1. The relative deformation δ between the dust particles and the transmission line... n The second time is 0, which indicates the moment after the dust particle collides with the transmission line. The corresponding end time is t2, and the corresponding dust particle velocity is υ2. The collision time τ = t2 - t1. Substituting into formula (7), we obtain the force F exerted by a single dust particle on the transmission line. d ;

[0065] As can be seen from formula (7), F d It is closely related to the impact velocity ν of dust particles. Figure 3 The variation of collision time τ with the impact velocity ν of dust particles is shown. Figure 4 F is shown d The variation law of impact velocity ν of dust particles;

[0066] Depend on Figure 3 It can be seen that as the impact velocity ν of dust particles increases, the number of collision events decreases exponentially; from Figure 4 It can be seen that as the impact velocity ν of dust particles increases, F d The approximate linear trend increases.

[0067] Furthermore, in step S4, the stress f exerted by the dust particles on the transmission line is obtained from formula (8).

[0068]

[0069] In the formula, F d Let α be the force exerted by a single dust particle on the power transmission line, N be the number of dust particles per unit volume, and α be the average probability of a dust particle colliding with the power transmission line.

[0070] In this embodiment, the surface on which the stress exerted by the dust particles on the transmission line is taken as a rectangular area with a length of 1m and a width of 2R. Figure 5 This shows that when the dust particle mass concentration c is 2 mg / m³ 3 N = 1.44 × 10 6 pcs / m 3When f changes with the dust particle velocity ν, where the radius R of the transmission line is 0.02m and the radius r of the dust particle is 5μm;

[0071] Figure 6 The variation of f with the radius R of the transmission line is shown, where the dust particle radius r is 5 μm and the impact velocity ν of the dust particle is 10 m / s;

[0072] Figure 7 The variation of f with the radius r of the dust particles is shown, where the impact velocity of the dust particles ν is 10 m / s, the radius R of the transmission line is 0.02 m, and the number of dust particles per unit volume is N = 1.44 × 10⁻⁶. 6 pcs / m 3 ;

[0073] Depend on Figure 5 It can be seen that as the impact velocity ν of dust particles increases, f increases approximately linearly;

[0074] Depend on Figure 6 It can be seen that as the radius R of the transmission line increases, f increases approximately linearly, indicating that the larger the size of the transmission line, the more significant the effect of dust particles on the transmission line becomes.

[0075] Depend on Figure 7 It can be seen that as the radius r of the dust particles increases, the myopia f increases exponentially; this indicates that the larger the size of the dust particles, the more attention should be paid to the stress they exert on the power transmission lines.

[0076] The method for calculating the stress exerted by dust particles on power transmission lines during sandstorms first obtains the probability α of a collision between a dust particle and a power transmission line based on the volume occupied by the power transmission line in space. Then, it uses the particle motion equation and elastic collision model to simulate the collision process of a single dust particle with the power transmission line, and obtains the force F exerted by a single dust particle on the power transmission line. d Finally, based on the force F exerted by a single dust particle on the transmission line... d This invention proposes a method for predicting the stress exerted by dust particles on power transmission lines by calculating the dust particle mass concentration c and the probability α of dust particles colliding with the transmission line. Compared with existing technologies that only consider the influence of wind load when studying the dynamic behavior of power transmission lines during sandstorms, this invention provides an important initial and boundary value condition for the study of the dynamic behavior of power transmission lines, making the study of the dynamic behavior of power transmission lines during sandstorms more accurate and reasonable. This provides a reliable and reasonable basis for the construction of power transmission lines in desert areas, and improves the safety of power transmission and power transmission in desert areas.

[0077] The above description discloses only preferred embodiments of the present invention and should not be construed as limiting the scope of the invention. Those skilled in the art will understand that implementing all or part of the above embodiments and making equivalent changes in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A method for calculating the stress exerted on power transmission lines by dust particles during a sandstorm, characterized in that, Includes the following steps: S1: Based on the volume occupied by the power transmission line in space, obtain the probability α of dust particles colliding with the power transmission line during a sandstorm. S2: Based on the elastic collision model and particle motion equation, simulate the process of a single dust particle colliding with a power transmission line during a sandstorm. S3: Obtain the force exerted by a single dust particle on a power transmission line from the simulation of the collision between a single dust particle and the power transmission line. ; S4: Based on the force exerted by a single dust particle on the power transmission line The stress exerted by dust particles on the transmission line is obtained by considering the dust particle mass concentration c and the probability α of dust particles colliding with the transmission line. ; In step S1, the probability α of dust particles colliding with power transmission lines during a sandstorm is the average probability, and α is given by the formula... The formula is obtained, where n is the number of dust particles that collide with the power transmission line per unit volume, and N is the number of dust particles per unit volume. （1） Where N is obtained from formula (2), and n is obtained from formula (2). get, （2） （3） In the formula, c is the mass concentration of dust particles during a sandstorm, m is the mass of a single dust particle, R is the radius of the transmission line, and r is the radius of a single dust particle. In step S2, the elastic collision model of a single dust particle with the transmission line is given by formula (4): （4） In the formula, For normal force, For the equivalent radius, For the equivalent Young's modulus; where, and The results are obtained from formulas (5) and (6) respectively: （5） （6） In the formula, and These are the Young's moduli of a single dust particle and a power transmission line, respectively. and These represent the Poisson's ratio of a single dust particle and that of a power transmission line, respectively. and These are the radii of a single dust particle and the radius of a power transmission line, respectively. This refers to the relative deformation of a single dust particle relative to the power transmission line; In step S3, Obtained from formula (7), （7） In the formula, m represents the mass of a single dust particle. and These represent the velocities of a single dust particle before and after impacting the power transmission line. This indicates the collision time between a single dust particle and the power transmission line; In step S4, the stress f exerted by the dust particles on the transmission line is obtained by formula (8). （8） In the formula, Let α be the force exerted by a single dust particle on the power transmission line, N be the number of dust particles per unit volume, and α be the average probability of a dust particle colliding with the power transmission line.

2. The method for calculating the stress exerted on power transmission lines by dust particles during a sandstorm as described in claim 1, characterized in that: The surface on which the dust particles exert stress on the transmission line is defined as a rectangular area with a length of 1m and a width of 2R, where R is the radius of the transmission line.

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