Optimized selection method for particle size parameters of water drops in conductor icing simulation

Abstract

The invention provides an optimal selection method for a water drop particle size parameter in conductor icing simulation, and relates to the technical field of conductor icing simulation, the method comprises the following steps: obtaining a water drop particle size parameter in air and a meteorological environment parameter under an icing condition; respectively calculating a water drop particle size distribution spectrum and a water drop median volume diameter in the air according to the water drop particle size parameters; calculating a first water drop overall collision coefficient according to the wire diameter, the water drop median volume diameter and the meteorological environment parameters; calculating a second water drop overall collision coefficient according to the wire diameter, the water drop particle size distribution spectrum and the meteorological environment parameters; and according to the size relationship between the first water drop overall collision coefficient and the second water drop overall collision coefficient, determining an optimal water drop particle size parameter in lead icing simulation. According to the scheme, the particle size parameters of the water drops can be optimized and selected, so that the accuracy of wire icing simulation is improved.

Description

Technical Field

[0001] The invention relates to the technical field of conductor ice coating simulation, and in particular to a method for optimizing and selecting water droplet diameter parameters in conductor ice coating simulation. Background Art

[0002] Transmission lines are an important part of the power network, connecting the power supply side and the power demand side, and are also the main channel for national power transmission. In most parts of my country, icing of overhead power transmission lines has become very common in winter, and icing may cause disasters such as overload, swaying, short circuit, fracture and tower collapse of transmission lines, seriously threatening the safety of power transmission. In recent years, with the rapid development of ultra-high voltage transmission lines and the continuous expansion of the scale of power grids in my country, the problem of line icing has become more prominent.

[0003] In the study of simulating and predicting the icing of wires, technicians in this field proposed modeling the water drop collision, capture and freezing process. The model calculated the water drop collision, capture and freezing coefficients based on fluid mechanics and thermodynamics, and quantified the wire icing rate through three coefficients, wind speed, liquid water content in the air and wire diameter. The research on the numerical calculation model of this method has broken through the shortcomings of the empirical formula and expanded the scope of application of the wire icing model, but at the same time, it has also put forward higher requirements for the calculation amount and the refined measurement of icing environment parameters. The results of the study show that various icing environment parameters including water droplet size and liquid water content in the air are still the dominant factors determining the wire icing rate. In another study using the water drop volume weighted diameter as a characterization parameter of the water droplet size, the results show that the parameter can better reflect its collision characteristics on the wire surface when the water droplet size is small. It can be seen that the selection of water droplet size is crucial to the accuracy of wire icing simulation, and the water droplet collision coefficient in the water droplet size parameter is more important for wire simulation research. However, the existing schemes lack the optimization selection of water droplet size parameters in the conductor icing simulation research, which leads to low accuracy of conductor icing simulation. Summary of the invention

[0004] In view of this, in order to address the above shortcomings, it is necessary to propose an optimization method for selecting water droplet size parameters in conductor icing simulation to improve the accuracy of conductor icing simulation.

[0005] In a first aspect, the present invention provides a method for optimizing and selecting water droplet size parameters in a conductor ice coating simulation, comprising:

[0006] Obtain the water droplet size parameters and meteorological environment parameters in the air under icing conditions;

[0007] Calculate the water droplet size distribution spectrum and the water droplet median volume diameter in the air according to the water droplet size parameters;

[0008] Calculating the first water droplet overall collision coefficient according to the wire diameter, the water droplet median volume diameter and the meteorological environment parameter;

[0009] Calculating the overall collision coefficient of the second water droplet according to the wire diameter, the water droplet particle size distribution spectrum and the meteorological environment parameter;

[0010] According to the magnitude relationship between the first water droplet overall collision coefficient and the second water droplet overall collision coefficient, an optimal water droplet particle size parameter in the wire icing simulation is determined.

[0011] Preferably, the step of obtaining the water droplet size parameters in the air under icing conditions includes:

[0012] Under ice-covered conditions, the water droplet size spectrum sensor is used to collect the number and size of water droplets;

[0013] Each water droplet is divided into different size ranges, and the water droplet size parameters are obtained based on the following calculation formula:

[0014]

[0015] Among them, W i It is used to characterize the i-th water droplet size interval, 2Δd is the range of a water droplet size interval, d m Used to characterize the i-th water droplet size interval W i The center diameter of the water droplet, N i It is used to characterize the number of water droplets in the i-th water droplet size interval, d x is the water droplet size value, and n is the number of water droplet size intervals.

[0016] Preferably, the calculating the water droplet size distribution spectrum in the air according to the water droplet size parameter comprises:

[0017] For each water droplet size range, calculate the ratio of the volume of all water droplets in the water droplet size range to the total water droplet volume P i , and obtain the water droplet size distribution spectrum; wherein the water droplet volume is calculated based on the water droplet size.

[0018] Preferably, the calculating the median volume diameter of the water droplets according to the water droplet size parameters comprises:

[0019] Will The center diameter d of the water droplet in the mth water droplet diameter interval m Determined as the median volume diameter of a water droplet; where m ≤ n.

[0020] Preferably, the calculating the first water droplet overall collision coefficient according to the wire diameter, the water droplet median volume diameter and the meteorological environment parameter comprises:

[0021] The function of the first water droplet overall collision coefficient is expressed as follows, and the function is solved using an analytical method to obtain the first water droplet overall collision coefficient:

[0022]

[0023] Among them, α1 is used to characterize the overall collision coefficient of the first water drop, C x1 ~C x12 is a constant coefficient, K and φ are the inertial parameters and Langmuir parameters of the water droplet motion, respectively, d and ρ a are the density of water droplets and air respectively, V is the wind speed, μ is the kinematic viscosity of air, D is the wire diameter, d m is the median volume diameter of a water droplet.

[0024] Preferably, the calculating the second water droplet overall collision coefficient according to the wire diameter, the water droplet particle size distribution spectrum and the meteorological environment parameter comprises:

[0025] The function of the overall collision coefficient of the second water droplet is expressed as follows, and the function is solved by an analytical method to obtain the overall collision coefficient of the second water droplet:

[0026]

[0027] Among them, α1′ is used to characterize the overall collision coefficient of the second water droplet, α 1,i It is used to characterize the overall collision coefficient of water droplets calculated based on the center diameter of water droplets in the i-th water droplet diameter interval, C x1 ~C x12 is a constant coefficient, K and φ are the inertial parameters and Langmuir parameters of the water droplet motion, respectively, d and ρ a are the density of water droplets and air respectively, V is the wind speed, μ is the kinematic viscosity of air, D is the wire diameter, d m is the median volume diameter of the water droplet, P i is the ratio of the volume of all water droplets in the i-th water droplet size interval to the total water droplet volume.

[0028] Preferably, determining the optimal water droplet size parameter in the wire icing simulation according to the magnitude relationship between the first water droplet overall collision coefficient and the second water droplet overall collision coefficient includes:

[0029] Calculating an absolute value of a difference between the first water droplet overall collision coefficient and the second water droplet overall collision coefficient;

[0030] Determine whether the calculated absolute value is less than a preset deviation threshold;

[0031] If the absolute value is less than the deviation threshold, the water droplet median volume diameter is determined as the optimal water droplet particle size parameter; otherwise, the water droplet particle size distribution spectrum is determined as the optimal water droplet particle size parameter.

[0032] Preferably, after determining the optimal water droplet size parameter in the conductor ice coating simulation, the method further includes:

[0033] If the water droplet median volume diameter is the optimal water droplet particle size parameter, the first water droplet overall collision coefficient is determined as the water droplet collision coefficient in the wire icing simulation calculation;

[0034] If the water droplet size distribution spectrum is the optimal water droplet size parameter, the Euler method is used to solve the function of the second water droplet overall collision coefficient, and the solved second water droplet overall collision coefficient is determined as the water droplet collision coefficient in the wire icing simulation calculation.

[0035] In a second aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to execute any of the methods described in the first aspect.

[0036] In a third aspect, the present invention provides a computing device, including a memory and a processor, wherein executable code is stored in the memory, and when the processor executes the executable code, any method described in the first aspect is implemented.

[0037] It can be seen from the above technical scheme that in the optimization selection scheme of water droplet size parameters in the conductor icing simulation provided by the present invention, the water droplet size parameters and meteorological environment parameters in the air under icing conditions are first obtained, and then the water droplet size distribution spectrum and the median volume diameter of the water droplets in the air are calculated respectively according to the water droplet size parameters; further, the first water droplet overall collision coefficient is calculated according to the conductor diameter, the median volume diameter of the water droplets and the meteorological environment parameters, and the second water droplet overall collision coefficient is calculated according to the conductor diameter, the water droplet size distribution spectrum and the meteorological environment parameters, so that the optimal water droplet size parameters in the conductor icing simulation can be determined according to the size relationship between the first water droplet overall collision coefficient and the second water droplet overall collision coefficient. It can be seen that this scheme optimizes the water droplet size parameters by combining the meteorological environment parameters and the conductor parameters, so that when the preferred water droplet size parameters are used to simulate the conductor icing, the accuracy of the conductor icing simulation can be improved. Moreover, when the preferred water droplet size parameters are used to simulate the conductor icing, the amount of simulation calculation can be reduced, thereby improving the efficiency of simulation calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A flow chart of a method for optimizing the selection of water droplet size parameters in a conductor icing simulation provided by an embodiment of the present invention.

[0039] Figure 2 It is a water droplet size distribution spectrum DSD.

[0040] Figure 3 This is a comparison chart of the water droplet collision coefficient calculated using the median volume diameter MVD of a water droplet with a wire diameter of 20 mm and the water droplet particle size distribution spectrum DSD.

[0041] Figure 4 This is a comparison chart of the water droplet collision coefficient calculated using the median volume diameter MVD of a water droplet with a wire diameter of 30 mm and the water droplet particle size distribution spectrum DSD. DETAILED DESCRIPTION

[0042] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0043] like Figure 1 As shown, the present invention provides a method for optimizing the selection of water droplet size parameters in wire ice coating simulation, and the method may include the following steps:

[0044] Step 101: Obtain water droplet size parameters and meteorological environment parameters in the air under icing conditions;

[0045] Step 102: Calculate the water droplet size distribution spectrum and the water droplet median volume diameter in the air according to the water droplet size parameters;

[0046] Step 103: Calculate the first water droplet overall collision coefficient according to the wire diameter, the water droplet median volume diameter and the meteorological environment parameters;

[0047] Step 104: calculating the overall collision coefficient of the second water droplet according to the wire diameter, the water droplet size distribution spectrum and the meteorological environment parameters;

[0048] Step 105: Determine the optimal water droplet size parameter in the conductor ice coating simulation according to the magnitude relationship between the first water droplet overall collision coefficient and the second water droplet overall collision coefficient.

[0049] In this embodiment, the water droplet size parameters are optimized and selected by combining the meteorological environment parameters and the conductor parameters, so that when the preferred water droplet size parameters are used to simulate the conductor icing, the accuracy of the conductor icing simulation can be improved. Moreover, when the preferred water droplet size parameters are used to simulate the conductor icing, the amount of simulation calculation can be reduced, thereby improving the simulation calculation efficiency.

[0050] For step 101, obtain water droplet size parameters and meteorological environment parameters in the air under icing conditions;

[0051] In this step, when obtaining the water droplet size parameters, consider using the water droplet size spectrum sensor to collect the number of water droplets and the water droplet size under ice conditions, and then divide each water droplet into size intervals. For example, the water droplet size parameters may include the water droplet size range and the number of water droplets Ni in each interval. You can set d x is the water droplet size, n(d x ) is the particle size per unit volume d x Specifically, the water droplet size parameter can be obtained based on the following calculation formula:

[0052]

[0053] Among them, W i It is used to characterize the i-th water droplet size interval, 2Δd is the range of a water droplet size interval, d m Used to characterize the i-th water droplet size interval W i The center diameter of the water droplet, N i It is used to characterize the number of water droplets in the i-th water droplet size interval, d x is the water droplet size value, and n is the number of water droplet size intervals.

[0054] In addition, it is possible to consider using meteorological sensors to obtain parameters such as wind speed V and temperature T.

[0055] In step 102, the water droplet size distribution spectrum and the water droplet median volume diameter in the air are calculated according to the water droplet size parameters;

[0056] In this step, when calculating the water droplet size distribution spectrum in the air, the proportion of the volume of all water droplets in each water droplet size interval to the total water droplet volume can be calculated. i , and obtain the water droplet size distribution spectrum; where the water droplet volume is calculated based on the water droplet size. For example, the liquid water content in the air measured by the water droplet size distribution spectrum sensor is w, and the water droplet size range is W i The liquid water content formed by the water droplets in the i , then P i =w i / w, P of each water droplet size range i Constitute the water droplet size distribution spectrum.

[0057] When calculating the median volume diameter of a water droplet, The center diameter d of the water droplet in the mth water droplet diameter interval m Determined as the median volume diameter of a water droplet; where m ≤ n.

[0058] In step 103, the overall collision coefficient of the first water drop is calculated according to the wire diameter, the median volume diameter of the water drop and the meteorological environment parameters;

[0059] In this step, the function of the overall collision coefficient of the first water droplet can be expressed as follows:

[0060]

[0061] Among them, α1 is used to characterize the overall collision coefficient of the first water drop, C x1 ~C x12 is a constant coefficient, K and φ are the inertial parameters and Langmuir parameters of the water droplet motion, respectively, d and ρ a are the density of water droplets and air respectively, V is the wind speed, μ is the kinematic viscosity of air, D is the wire diameter, d m is the median volume diameter of a water droplet.

[0062] Furthermore, by solving the function using an analytical method, the first water droplet overall collision coefficient can be obtained. In this way, since the calculation of the first water droplet overall collision coefficient and the second water droplet overall collision coefficient is used to compare and determine the optimal water droplet particle size parameters, the analytical method is considered for solving. Although the accuracy of this solution method is slightly lower, it has less calculation and higher calculation efficiency.

[0063] In step 104, the overall collision coefficient of the second water drop is calculated according to the wire diameter, the water droplet size distribution spectrum and the meteorological environment parameters;

[0064] In this step, the function of the overall collision coefficient of the second water droplet can be expressed as follows:

[0065]

[0066] Among them, α1′ is used to characterize the overall collision coefficient of the second water droplet, α 1,i It is used to characterize the overall collision coefficient of water droplets calculated based on the center diameter of water droplets in the i-th water droplet diameter interval, C x1 ~C x12 is a constant coefficient, K and φ are the inertial parameters and Langmuir parameters of the water droplet motion, respectively, d and ρ a are the density of water droplets and air respectively, V is the wind speed, μ is the kinematic viscosity of air, D is the wire diameter, d m is the median volume diameter of the water droplet, P i is the ratio of the volume of all water droplets in the i-th water droplet size interval to the total water droplet volume.

[0067] Furthermore, the second water droplet overall collision coefficient is obtained by solving the function using an analytical method. The reason for using the analytical method is the same as that for the first water droplet overall collision coefficient.

[0068] In step 105, the optimal water droplet size parameter in the wire icing simulation is determined according to the magnitude relationship between the first water droplet overall collision coefficient and the second water droplet overall collision coefficient;

[0069] In this step, the absolute value of the difference between the overall collision coefficient of the first water droplet and the overall collision coefficient of the second water droplet is first calculated; specifically, Δα1=|α1-α1′|; then a determination is made as to whether the calculated absolute value Δα1 is less than a preset deviation threshold ε; if Δα1<ε, the median volume diameter of the water droplet is determined as the optimal water droplet particle size parameter; otherwise, the water droplet particle size distribution spectrum is determined as the optimal water droplet particle size parameter.

[0070] Furthermore, after determining the optimal water droplet size parameter in the conductor ice coating simulation, the method further includes:

[0071] If the median volume diameter of the water droplet is the optimal water droplet particle size parameter, the first water droplet overall collision coefficient is determined as the water droplet collision coefficient in the wire ice coating simulation calculation;

[0072] If the water droplet size distribution spectrum is the optimal water droplet size parameter, the Euler method is used to solve the function of the second water droplet overall collision coefficient, and the solved second water droplet overall collision coefficient is determined as the water droplet collision coefficient in the wire icing simulation calculation.

[0073] In this step, when the droplet size distribution spectrum is the optimal droplet size parameter, consider using the Euler method to re-solve the second droplet overall collision coefficient, and use the second droplet overall collision coefficient calculated at this time as the droplet collision coefficient in the wire icing simulation calculation. Since the results obtained by the Euler method are more accurate, the wire icing simulation research can also obtain more accurate simulation results, and the simulation calculation amount will also be greatly reduced.

[0074] Specifically, when conducting conductor icing simulation research, the following calculation formula is usually used to describe the icing rate:

[0075]

[0076] Among them, D is the wire diameter, L is the wire length, α1, α2, α3 are the water drop collision coefficient, capture coefficient and freezing coefficient respectively, V is the wind speed, and w is the liquid water content in the air. In this way, by using the optimized water drop collision coefficient to simulate the wire icing, the simulation results can be obtained more quickly and accurately.

[0077] The following is an explanation of this scheme with specific experimental data.

[0078] like Figure 2The water droplet size distribution spectrum DSD obtained is shown in FIG. 1, which has 10 intervals, each interval range is 2Δd = 5 μm, and the median volume diameter MVD of the water droplet corresponding to the water droplet size distribution spectrum is 16.5 μm. Figure 3-4 As shown in the figure, the median volume diameter MVD of water droplets and the water droplet size distribution spectrum DSD are used as inputs to calculate the variation of water droplet collision coefficient on the surface of wires with diameters of 20 mm and 30 mm with wind speed. It can be seen from the figure that if the acceptable α1 first error ε is ±10%, for a wire with a diameter of 20 mm, the median volume diameter MVD of water droplets can be used instead of the water droplet size distribution spectrum DSD to calculate the water droplet collision coefficient only when the wind speed V≥9.4m / s. If the wire diameter increases to 30mm, the critical wind speed should be increased to 15m / s. Therefore, based on this scheme, accurate parameter selection and parameter setting can be performed, which can greatly improve the accuracy of wire icing simulation research.

[0079] The present specification also provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed in a computer, the computer is caused to execute a method in any one of the embodiments in the specification.

[0080] The present specification also provides a computing device, including a memory and a processor, wherein executable codes are stored in the memory, and when the processor executes the executable codes, a method in any embodiment of the present specification is implemented.

[0081] Since the device embodiments provided by the present invention are based on the same inventive concept as the method embodiments of this specification, the specific contents can be found in the description of the method embodiments of this specification and will not be repeated here.

[0082] The modules or units in the device of the embodiment of the present invention can be combined, divided and deleted according to actual needs. The above disclosure is only the preferred embodiment of the present invention, and of course it cannot be used to limit the scope of the rights of the present invention. Those skilled in the art can understand that all or part of the processes of the above embodiment are implemented, and the equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A method for optimizing the water droplet size parameters in wire icing simulation, characterized in that: include: Obtain the water droplet size parameters and meteorological environment parameters in the air under icing conditions; Calculate the water droplet size distribution spectrum and the water droplet median volume diameter in the air according to the water droplet size parameters; Calculating the first water droplet overall collision coefficient according to the wire diameter, the water droplet median volume diameter and the meteorological environment parameter; Calculating the overall collision coefficient of the second water droplet according to the wire diameter, the water droplet particle size distribution spectrum and the meteorological environment parameter; According to the magnitude relationship between the first water droplet overall collision coefficient and the second water droplet overall collision coefficient, an optimal water droplet particle size parameter in the wire icing simulation is determined.

2. The method for optimizing the water droplet size parameters in the conductor ice coating simulation according to claim 1 is characterized in that: The step of obtaining the water droplet size parameters in the air under icing conditions includes: Under ice-covered conditions, the water droplet size spectrum sensor is used to collect the number and size of water droplets; Each water droplet is divided into different size ranges, and the water droplet size parameters are obtained based on the following calculation formula: Among them, W i It is used to characterize the i-th water droplet size interval, 2Δd is the range of a water droplet size interval, d m Used to characterize the i-th water droplet size interval W i The center diameter of the water droplet, N i It is used to characterize the number of water droplets in the i-th water droplet size interval, d x is the water droplet size value, and n is the number of water droplet size intervals.

3. The method for optimizing the water droplet size parameters in the conductor ice coating simulation according to claim 2 is characterized in that: The step of calculating the water droplet size distribution spectrum in the air according to the water droplet size parameter comprises: For each water droplet size range, calculate the ratio of the volume of all water droplets in the water droplet size range to the total water droplet volume P i , and obtain the water droplet size distribution spectrum; wherein the water droplet volume is calculated based on the water droplet size.

4. The method for optimizing the water droplet size parameters in the conductor ice coating simulation according to claim 3 is characterized in that: The calculating the median volume diameter of the water droplets according to the water droplet diameter parameters comprises: Will The center diameter d of the water droplet in the mth water droplet diameter interval m Determined as the median volume diameter of a water droplet; where m ≤ n.

5. The method for optimizing the water droplet size parameters in the conductor ice coating simulation according to claim 1, characterized in that: The calculating of the first water droplet overall collision coefficient according to the wire diameter, the water droplet median volume diameter and the meteorological environment parameter comprises: The function of the first water droplet overall collision coefficient is expressed as follows, and the function is solved using an analytical method to obtain the first water droplet overall collision coefficient: Among them, α1 is used to characterize the overall collision coefficient of the first water drop, C x1 ~C x12 is a constant coefficient, K and φ are the inertial parameters and Langmuir parameters of the water droplet motion, respectively, d and ρ a are the density of water droplets and air respectively, V is the wind speed, μ is the kinematic viscosity of air, D is the wire diameter, d m is the median volume diameter of a water droplet.

6. The method for optimizing the water droplet size parameters in the conductor ice coating simulation according to claim 1, characterized in that: The calculating of the second water droplet overall collision coefficient according to the wire diameter, the water droplet particle size distribution spectrum and the meteorological environment parameter comprises: The function of the overall collision coefficient of the second water droplet is expressed as follows, and the function is solved by an analytical method to obtain the overall collision coefficient of the second water droplet: Among them, α1′ is used to characterize the overall collision coefficient of the second water droplet, α 1,i It is used to characterize the overall collision coefficient of water droplets calculated based on the center diameter of water droplets in the i-th water droplet diameter interval, C x1 ~C x12 is a constant coefficient, K and φ are the inertial parameters and Langmuir parameters of the water droplet motion, respectively, d and ρ a are the density of water droplets and air respectively, V is the wind speed, μ is the kinematic viscosity of air, D is the wire diameter, d m is the median volume diameter of the water droplet, P i is the ratio of the volume of all water droplets in the i-th water droplet size range to the total water droplet volume.

7. The method for optimizing the water droplet size parameters in the conductor ice coating simulation according to claim 1, characterized in that: The determining of the optimal water droplet size parameter in the wire icing simulation according to the magnitude relationship between the first water droplet overall collision coefficient and the second water droplet overall collision coefficient includes: Calculating an absolute value of a difference between the first water droplet overall collision coefficient and the second water droplet overall collision coefficient; Determine whether the calculated absolute value is less than a preset deviation threshold; If the absolute value is less than the deviation threshold, the water droplet median volume diameter is determined as the optimal water droplet particle size parameter; otherwise, the water droplet particle size distribution spectrum is determined as the optimal water droplet particle size parameter.

8. The method for optimizing the water droplet size parameters in the conductor ice coating simulation according to claim 6, characterized in that: After determining the optimal water droplet size parameters in the conductor ice simulation, the following steps are further considered: If the water droplet median volume diameter is the optimal water droplet particle size parameter, the first water droplet overall collision coefficient is determined as the water droplet collision coefficient in the wire icing simulation calculation; If the water droplet size distribution spectrum is the optimal water droplet size parameter, the Euler method is used to solve the function of the second water droplet overall collision coefficient, and the solved second water droplet overall collision coefficient is determined as the water droplet collision coefficient in the wire icing simulation calculation.

9. A computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to execute the method according to any one of claims 1 to 8.

10. A computing device comprising a memory and a processor, wherein the memory stores executable codes, and when the processor executes the executable codes, the method according to any one of claims 1 to 8 is implemented.

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