Wind deflection calculation correction method, device and medium considering characteristics of pulsating wind in Tibet

Abstract

The application discloses a wind deviation calculation correction method and device considering the characteristics of pulsating wind in Tibet, and a medium, belongs to the technical field of wind deviation calculation of overhead transmission lines, and comprises the following steps: through analyzing the measured data of a wind measuring point in Tibet, a wind speed along the wind direction is obtained, and the wind speed is subjected to empirical mode decomposition to be decomposed into the sum of time-varying average wind speed and stationary pulsating wind speed; selected samples are extracted as effective data, the effective data are fitted by using the Morison coordinates of the Davenport spectrum, and the fitting wind spectrum of Tibet can be obtained; the wind deviation angles under different working conditions are calculated by using the specification method and the fitting wind spectrum respectively, then the pulsating reduction coefficients under different working conditions are corrected, and the corrected coefficients and formulas are obtained. The application can divide the finite element wind deviation response solving calculation into two steps of static force calculation and linear dynamic calculation, avoids time-consuming iterative calculation, is similar to the calculation result of the time domain method, and is simple, fast and easy to calculate.

Description

Technical Field

[0001] This invention relates to the field of wind deflection calculation technology for overhead transmission lines, and more specifically, to a wind deflection calculation correction method, equipment, and medium that takes into account the characteristics of pulsating winds in Tibet. Background Technology

[0002] For many years, severe winds have threatened the safe operation of transmission lines in the Tibetan power grid. Wind-induced flashover accidents on transmission lines caused by strong winds are frequent, widespread, and severe. Statistics show that since 2009, severe weather has been frequent, and due to inadequate design, poor construction quality, and improper operation and maintenance, wind-induced faults on 110-220kV transmission lines have increased significantly. In 2009, a severe wind caused a complete power outage in the Nagqu power grid of the Nagqu Power Company in Tibet; in the same year, a short circuit on the Gaxi 110kV line of the Lhasa Power Bureau in Tibet caused a large-scale reduction in system load due to strong winds.

[0003] Therefore, in order to ensure the safe operation of high-voltage transmission lines in Tibet, it is necessary to conduct in-depth research on the accurate calculation of wind deflection of suspension insulator strings during the design process of the Tibet power grid lines, so as to prevent damage accidents such as wind deflection flashover. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a wind deflection calculation correction method, device and medium that takes into account the characteristics of pulsating wind in Tibet. It can reflect the characteristics of pulsating wind in Tibet into the pulsation reduction coefficient, thereby more accurately calculating the wind deflection of overhead transmission lines and effectively preventing the wind deflection protection design from being dangerous.

[0005] The objective of this invention is achieved through the following solution:

[0006] A wind deflection calculation correction method considering the characteristics of pulsating winds in Tibet includes the following steps:

[0007] S1. Using measured data from wind measurement points in Tibet, the downwind speed is obtained and empirically decomposed into the sum of time-varying average wind speed and steady-state fluctuating wind speed.

[0008] S2, perform empirical mode decomposition on the downwind speed according to the intensity of oscillation, and take the remainder and the sum of the last intrinsic mode function (IMF) as the time history of the time-varying wind speed;

[0009] S3, the selected samples are extracted as valid data for wind speed spectrum analysis in Tibetan areas;

[0010] S4, use the Moning coordinates of the Davenport spectrum to fit the effective data in step S3;

[0011] S5. The wind deflection angle under different working conditions was calculated using the standard method and the fitted wind spectrum, respectively.

[0012] S6. Based on the wind deflection angle calculated in step S5 under different working conditions, the pulsation reduction coefficient under different spans and voltage levels is corrected so that the corrected standard calculated wind deflection angle is equal to the fitted spectrum finite element result.

[0013] Further, step S1 includes the following sub-steps:

[0014] Using a set time interval as the time difference and a set value between two samples, the wind speed data acquired from the wind measurement point is vectorized. That is, with due north as the x-axis and due east as the y-axis, the measured wind speed at each moment is decomposed onto the x and y axes according to the wind direction angle at each moment, and the average wind speed in the x and y directions is calculated respectively. And obtain the prevailing wind angle

[0015]

[0016]

[0017]

[0018] The measured wind speed is along the prevailing wind direction angle. Decomposition yields the downwind speed v along the prevailing wind direction angle. x :

[0019]

[0020] Further, step S2 includes the sub-step: measuring the downwind speed v over a set time interval. x (t) is decomposed into time-varying average wind speed With steady pulsating wind speed v x * The sum of (t).

[0021] Furthermore, in step S3, the selected sample includes data where the average wind speed in the downwind direction is greater than a set value.

[0022] Furthermore, step S4 includes the following sub-steps:

[0023] The Davenport fitting form is:

[0024]

[0025] In the formula, S u (z, n) represents the power spectrum of fluctuating wind speed, k is the roughness coefficient, n is the frequency of fluctuating wind speed, and v 10 The standard wind speed is 10m above the ground. A and B are constant parameters, and C and D are power parameters.

[0026] The least squares method was used to fit the data in MATLAB, obtaining four parameters: A, B, C, and D. The fitted wind spectrum is as follows:

[0027]

[0028] Furthermore, step S5 includes the following sub-steps: under different working conditions, wind load is derived by using the frequency domain method based on the fitted wind spectrum, the finite element working conditions are set, and then the wind deflection angle is obtained by finite element calculation. At the same time, the wind deflection angle is calculated using the method required by the specification.

[0029] Furthermore, in step S1, the set duration of the time interval includes 10 minutes.

[0030] Furthermore, in step S1, the interval between the two samples includes 3 minutes.

[0031] A computer device includes a processor and a memory, the memory storing a computer program that, when loaded by the processor, executes the method as described in any of the preceding claims.

[0032] A computer-readable storage medium storing a computer program therein, the computer program being loaded by a processor and executing the method as described in any of the preceding claims.

[0033] The beneficial effects of this invention include:

[0034] (1) The present invention can take into account the pulsating wind characteristics of Tibet into the wind deflection calculation, and can accurately reflect the wind deflection response in the power transmission line project in Tibet.

[0035] (2) The present invention has wind deflection response in transmission line engineering in Tibet. It can accurately calculate the wind deflection of suspension insulator strings in the design and avoid wind deflection flashover caused by insufficient gap consideration.

[0036] (3) The present invention is technologically advanced, has superior performance, and is relatively easy to implement.

[0037] (4) The present invention can divide the solution calculation of finite element wind deflection response into two steps: static calculation and linear dynamic calculation, avoiding time-consuming iterative calculation, and the calculation results are similar to those of the time domain method, making the calculation simple and fast.

[0038] (5) The wind deflection calculation method of the present invention is adapted to the wind deflection response of the conductor under the action of the pulsating wind field in Tibet, and can effectively prevent the wind deflection design from being dangerous. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a flowchart of the wind deflection calculation and correction method considering the characteristics of pulsating winds in Tibet, as described in an embodiment of the present invention.

[0041] Figure 2 This is a finite element model and a schematic diagram of wind load in an embodiment of the present invention;

[0042] Figure 3 To compare the results before and after correction. Detailed Implementation

[0043] All features disclosed in all embodiments of this specification, or steps in all methods or processes implied in the disclosure, may be combined and / or extended or replaced in any way, except for mutually exclusive features and / or steps.

[0044] In view of the technical problems mentioned in the background, the inventors of this invention have made creative efforts. Domestic and international standards generally use the rigid straight bar method for calculating wind deflection of transmission line conductors. This method treats the wind load and gravity load of the conductor as concentrated forces applied to the lower end of the suspension insulator string, and then performs a static equilibrium analysis to obtain the wind deflection angle of the insulator string. While the rigid straight bar method has a clear force distribution and is simple to calculate, it fails to consider the influence of dynamic amplification effects, aerodynamic coefficients, and terrain conditions on conductor wind deflection, significantly underestimating the wind deflection response of transmission lines. To account for these factors, standards provide suggested calculation methods for wind load amplification factors and span reduction factors, enabling the calculation results to reflect the wind deflection response in general engineering projects. However, the wind field characteristics in Tibet may differ significantly from other regions, and the standard calculations cannot accurately calculate the wind deflection response of transmission lines in Tibet. Therefore, this invention proposes a wind deflection calculation correction scheme that considers the pulsating wind characteristics of Tibet.

[0045] In a further embodiment, the following steps are included:

[0046] Step 1: Using a 10-minute time interval and a 3-minute interval between two samples, perform vector decomposition on the wind speed data obtained from the anemometer point. That is, using due north as the x-axis and due east as the y-axis, decompose the measured wind speed at each moment onto the x and y axes according to the wind direction angle at each moment, and calculate the average wind speed in the x and y directions respectively. And obtain the prevailing wind angle

[0047]

[0048]

[0049]

[0050] The measured wind speed is along the prevailing wind direction angle. Decomposition yields the downwind speed v along the prevailing wind direction angle. x :

[0051]

[0052] Step two, adjust the downwind speed v according to the intensity of the oscillation. x Empirical mode decomposition is performed, and the sum of the residual and the last IMF is taken as the time history of the time-varying wind speed. Therefore, the measured downwind wind speed v over a 10-minute interval is used. x (t) is decomposed into time-varying average wind speed With steady pulsating wind speed v x * The sum of (t).

[0053] Step 3: Extract the samples with a 10-minute downwind average wind speed greater than 8 m / s as valid data for wind speed spectrum analysis in Tibetan areas.

[0054] Step four: Fit the effective data using the Moning coordinates of the Davenport spectrum. The fitting form (Davenport) is as follows:

[0055]

[0056] The least squares method was used to fit the data in MATLAB, obtaining four parameters: A, B, C, and D. The fitted wind spectrum is as follows:

[0057] Step 5: Calculate the wind deflection angle under different working conditions using the standard method and the fitted wind spectrum. Under different working conditions, the wind load is derived using the frequency domain method based on the fitted wind spectrum. The finite element working conditions are set as shown in Tables 1-3. Then, the wind deflection angle is obtained by finite element calculation as shown in Table 4. At the same time, the wind deflection angle is calculated using the method required by the standard, and the results are shown in Table 4.

[0058] Table 1 Conductor Parameters

[0059]

[0060] Table 2 Insulator string parameters

[0061]

[0062] Table 3 Calculation Condition Table

[0063]

[0064] Table 4 Calculation Results

[0065]

[0066] Step 6: Based on the wind deflection angles calculated in Step 5 for different operating conditions, adjust the pulsation reduction factor ε for different spans and voltage levels. c,mod The standard wind deflection angle is corrected to match the fitted finite element result. Specifically, the α value in the wind load calculation formula of DL / T 5582-2020 is adjusted. L The pulsation reduction coefficient ε in c,mod Make corrections so that the corrected wind deflection angle calculated according to the standard is equal to the finite element result of the fitted spectrum, that is, make... Among them W c,mod =β c α L,mod W0μ z μ sc dL p B1sin 2 θ, Based on this, the corrected pulsation reduction coefficient ε can be obtained. c,mod As shown in Table 5. The results before and after correction are as follows. Figure 3 As shown.

[0067] Table 5 Correction Coefficients

[0068]

[0069] This invention discloses a wind deflection calculation correction method considering the pulsating wind characteristics of Tibet. By analyzing measured data from wind measurement points in Tibet, the downwind wind speed is obtained and subjected to empirical mode decomposition, decomposing it into the sum of time-varying average wind speed and steady pulsating wind speed. Samples with a 10-minute downwind average wind speed greater than 8 m / s are extracted as valid data. The valid data are fitted using the Moning coordinates of the Davenport spectrum to obtain the fitted wind spectrum for Tibet. The wind deflection angle under different operating conditions is calculated using standard methods and the fitted wind spectrum, and then the pulsating reduction coefficient under different operating conditions is corrected to obtain the corrected coefficients and formulas. This invention can divide the finite element wind deflection response calculation into two steps: static calculation and linear dynamic calculation, avoiding time-consuming iterative calculations. The results are similar to those of the time-domain method, and the calculation is simple and fast.

[0070] It should be noted that, within the scope of protection defined in the claims of this invention, the following embodiments can be combined and / or extended or replaced in any logical manner from the above specific embodiments, such as the disclosed technical principles, disclosed technical features or implicitly disclosed technical features.

[0071] Example 1

[0072] A wind deflection calculation correction method considering the characteristics of pulsating winds in Tibet includes the following steps:

[0073] S1. Using measured data from wind measurement points in Tibet, the downwind speed is obtained and empirically decomposed into the sum of time-varying average wind speed and steady-state fluctuating wind speed.

[0074] S2, perform empirical mode decomposition on the downwind speed according to the intensity of oscillation, and take the remainder and the sum of the last intrinsic mode function (IMF) as the time history of the time-varying wind speed;

[0075] S3, the selected samples are extracted as valid data for wind speed spectrum analysis in Tibetan areas;

[0076] S4, use the Moning coordinates of the Davenport spectrum to fit the effective data in step S3;

[0077] S5. The wind deflection angle under different working conditions was calculated using the standard method and the fitted wind spectrum, respectively.

[0078] S6. Based on the wind deflection angle calculated in step S5 under different working conditions, the pulsation reduction coefficient under different spans and voltage levels is corrected so that the corrected standard calculated wind deflection angle is equal to the fitted spectrum finite element result.

[0079] Example 2

[0080] Based on Example 1, step S1 includes the following sub-steps:

[0081] Using a set time interval as the time difference and a set value between two samples, the wind speed data acquired from the wind measurement point is vectorized. That is, with due north as the x-axis and due east as the y-axis, the measured wind speed at each moment is decomposed onto the x and y axes according to the wind direction angle at each moment, and the average wind speed in the x and y directions is calculated respectively. And obtain the prevailing wind angle

[0082]

[0083]

[0084]

[0085] The measured wind speed is along the prevailing wind direction angle. Decomposition yields the downwind speed v along the prevailing wind direction angle. x :

[0086]

[0087] Example 3

[0088] Based on Example 1, step S2 includes the following sub-step: measuring the downwind speed v over a set time interval. x (t) is decomposed into time-varying average wind speed With steady pulsating wind speed v x * The sum of (t).

[0089] Example 4

[0090] Based on Example 1, in step S3, the selected sample includes data where the average wind speed in the downwind direction is greater than a set value.

[0091] Example 5

[0092] Based on Example 1, step S4 includes the following sub-steps:

[0093] The Davenport fitting form is:

[0094]

[0095] In the formula, S u (z, n) represents the power spectrum of fluctuating wind speed, k is the roughness coefficient, n is the frequency of fluctuating wind speed, and v 10 The standard wind speed is 10m above the ground. A and B are constant parameters, and C and D are power parameters.

[0096] The least squares method was used to fit the data in MATLAB, obtaining four parameters: A, B, C, and D. The fitted wind spectrum is as follows:

[0097]

[0098] Example 6

[0099] Based on Examples 1 to 5, step S5 includes the following sub-steps: under different working conditions, wind load is derived by using the frequency domain method according to the fitted wind spectrum, the finite element working conditions are set, and then the wind deflection angle is obtained by finite element calculation. At the same time, the wind deflection angle is calculated using the method required by the specification.

[0100] Example 7

[0101] Based on Example 2, in step S1, the set duration of the time interval includes 10 minutes.

[0102] Example 8

[0103] Based on Example 2, in step S1, the interval between the two samples includes 3 minutes.

[0104] Example 9

[0105] A computer device includes a processor and a memory, wherein the memory stores a computer program that, when loaded by the processor, executes the method described in any one of Embodiments 1 to 8.

[0106] Example 10

[0107] A computer-readable storage medium storing a computer program, the computer program being loaded by a processor and executed as described in any one of Examples 1 to 8.

[0108] The units described in the embodiments of the present invention can be implemented in software or hardware, and the described units can also be located in a processor. The names of these units do not necessarily limit the specific unit itself.

[0109] According to one aspect of the present invention, a computer program product or computer program is provided, the computer program product or computer program including computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium, and executes the computer instructions, causing the computer device to perform the methods provided in the various optional implementations described above.

[0110] In another aspect, embodiments of the present invention also provide a computer-readable medium, which may be included in the electronic device described in the above embodiments; or it may exist independently and not assembled into the electronic device. The computer-readable medium carries one or more programs, which, when executed by the electronic device, cause the electronic device to perform the methods described in the above embodiments.

[0111] All parts not covered in this invention are the same as or can be implemented using existing technologies.

[0112] The above technical solution is only one embodiment of the present invention. For those skilled in the art, based on the application methods and principles disclosed in the present invention, it is easy to make various types of improvements or modifications, and not limited to the methods described in the above specific embodiments of the present invention. Therefore, the methods described above are only preferred and are not restrictive.

[0113] In addition to the examples above, other embodiments may be obtained by those skilled in the art based on the above disclosure or by making modifications using knowledge or technology in related fields. The features of each embodiment may be interchanged or replaced. Modifications and changes made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A method for calculating and correcting wind deflection considering the characteristics of pulsating winds in Tibet, characterized in that, Includes the following steps: S1. Using measured data from wind measurement points in Tibet, the downwind speed is obtained and empirically decomposed into the sum of time-varying average wind speed and steady-state fluctuating wind speed. S2, perform empirical mode decomposition on the downwind speed according to the intensity of oscillation, and take the remainder and the sum of the last intrinsic mode function (IMF) as the time history of the time-varying wind speed; S3, the selected samples are extracted as valid data for wind speed spectrum analysis in Tibetan areas; S4, use the Moning coordinates of the Davenport spectrum to fit the effective data in step S3; S5. The wind deflection angle under different working conditions was calculated using the standard method and the fitted wind spectrum, respectively. S6. Based on the wind deflection angle calculated in step S5 under different working conditions, the pulsation reduction coefficient under different spans and voltage levels is corrected so that the corrected standard calculated wind deflection angle is equal to the fitted spectrum finite element result. Step S1 includes the following sub-steps: Using a set time interval as the time difference and a set value between two samples, the wind speed data acquired from the wind measurement point is vectorized. That is, with due north as the x-axis and due east as the y-axis, the measured wind speed at each moment is decomposed onto the x and y axes according to the wind direction angle at each moment, and the average wind speed in the x and y directions is calculated respectively. , And obtain the prevailing wind angle : （1） ， （2） （3） The measured wind speed is along the prevailing wind direction angle. Decomposition yields the downwind speed along the prevailing wind direction. : （4）； Step S2 includes the sub-step: measuring the downwind speed over a set time interval. Decomposed into time-varying average wind speed With steady pulsating wind speed sum.

2. The wind deflection calculation correction method considering the characteristics of pulsating winds in Tibet according to claim 1, characterized in that, In step S3, the selected sample includes data where the average wind speed in the downwind direction is greater than a set value.

3. The wind deflection calculation correction method considering the characteristics of pulsating winds in Tibet according to claim 1, characterized in that, Step S4 includes the following sub-steps: The Davenport fitting form is: （5） In the formula, S u ( z, n ( ) represents the power spectrum of fluctuating wind speed. k Roughness coefficient n The frequency of the pulsating wind speed. v 10 The standard wind speed is 10m above the ground. A and B are constant parameters, and C and D are power parameters. The least squares method was used to fit the data in MATLAB, obtaining four parameters: A, B, C, and D. The fitted wind spectrum is as follows: （6）。 4. The wind deflection calculation correction method considering the characteristics of pulsating winds in Tibet according to any one of claims 1 to 3, characterized in that, Step S5 includes the following sub-steps: under different working conditions, wind load is derived by using the frequency domain method based on the fitted wind spectrum, the finite element working conditions are set, and then the wind deflection angle is obtained by finite element calculation. At the same time, the wind deflection angle is calculated using the method required by the standard.

5. The wind deflection calculation correction method considering the characteristics of pulsating winds in Tibet according to claim 1, in step S1, the set duration of the time interval includes 10 minutes.

6. The wind deflection calculation correction method considering the characteristics of pulsating winds in Tibet according to claim 1, characterized in that, In step S1, the interval between the two samples includes 3 minutes.

7. A computer device, characterized in that, The computer device includes a processor and a memory, the memory storing a computer program that, when loaded by the processor, executes the method as described in any one of claims 1 to 6.

8. A computer-readable storage medium, characterized in that, A computer program is stored in a readable storage medium, the computer program being loaded by a processor and executing the method as described in any one of claims 1 to 6.

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