A numerical simulation method for dynamic cable control for emergency arrest of transmission line

Abstract

The present invention discloses a numerical simulation method for dynamic cable control for emergency anti-dancing of power transmission lines, which first calculates the aerodynamic load of ice on the conductor at any angle; then establishes a finite element model of the conductor without the emergency cable installed; writes a first user-defined unit and a custom program that can apply the aerodynamic load in real time; obtains the dancing characteristics of the conductor; applies the emergency cable to the dancing crest position; writes a second user-defined unit and a third user-defined unit, the second user-defined unit realizes the real-time application of the aerodynamic load according to the angle of the conductor, and the third user-defined unit is used to read the displacement motion state of the emergency cable and the conductor connection end, determine the application method of the cable tightening end load, and finally compares the dancing characteristics of the conductor before and after the installation of the emergency cable, and analyzes and obtains the anti-dancing effect of the emergency cable. Accurate simulation analysis of the dancing characteristics of the emergency device installed during the line dancing process and accurate evaluation of the anti-dancing efficiency are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of anti-galloping of power transmission lines, and in particular relates to a numerical simulation method for dynamic cable control for emergency anti-galloping of power transmission lines. Background Art

[0002] The galloping of transmission lines refers to the formation of an asymmetric circular cross-section after the conductor is covered with ice in winter, which produces a low-frequency, large-amplitude self-excited vibration under the action of wind load. The formation of galloping mainly depends on the conductor icing, wind excitation and line structural parameters. Galloping usually lasts for a long time and can easily cause phase-to-phase flashover, resulting in major accidents such as tripping and power outages, conductor damage, line breakage, hardware damage and tower collapse. It is extremely harmful to the operation of the transmission system, seriously affecting the safe operation of the line and causing huge national economic losses. The design and management of transmission line anti-galloping mainly rely on the galloping distribution map, and anti-galloping devices are installed in areas with higher risks. In reality, there are cases of severe galloping in low-risk galloping areas, and the lines with anti-galloping devices installed still have galloping under extremely severe meteorological conditions.

[0003] Existing literature on the research of transmission line galloping mainly includes mechanism research, wind tunnel test research, real-type test research, and numerical simulation research. Among them, numerical simulation research has the advantages of convenience, rapidity and strong applicability, and has gradually become an important means of galloping analysis. However, the current galloping numerical simulation research mainly focuses on the pre-analysis and evaluation before the galloping occurs, analyzing the galloping characteristics of the line before and after the installation of the anti-galloping device, and evaluating the anti-galloping performance of the anti-galloping device. It is impossible to simulate the anti-galloping performance of the emergency measures installed during the line galloping process in real time. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a numerical simulation method for dynamic cable control for emergency anti-dancing of transmission lines, so as to realize accurate simulation analysis of the dancing characteristics of the emergency device installed during the line dancing process and accurate evaluation of the anti-dancing efficiency, and provide theoretical and data support for line emergency disposal.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A numerical simulation method for dynamic cable control for emergency stopping of transmission lines, the simulation method comprising the following steps:

[0007] S1: Determine the aerodynamic load of iced conductors: Use numerical simulation methods to determine the aerodynamic load of iced conductors under wind attack angles ranging from 0 to 360 degrees;

[0008] S2: Establish a finite element model of a typical line segment: Establish a finite element analysis model of the line that includes the conductor and spacer structure information;

[0009] S3: writing a first user-defined unit and a user-defined subroutine for applying aerodynamic loads, realizing real-time calculation and application of aerodynamic loads, and realizing numerical simulation of line galloping;

[0010] S4: Wire galloping characteristics analysis: Through the aerodynamic load obtained in S1 and the finite element model established in S2, combined with the first user-defined unit and the custom subroutine in S3, the wire galloping characteristics are analyzed. The wire galloping characteristics include the starting time, frequency, order and galloping amplitude parameters of the wire galloping;

[0011] S5: Establish a galloping analysis model including the emergency cable: Based on the conductor galloping characteristics obtained in S4, an emergency cable is installed at the conductor galloping wave crest, and a finite element model including the emergency cable is established. Based on the conductor galloping period and galloping amplitude, a periodically changing tensioning force is applied to the emergency cable to simulate the dynamic tightening process of the emergency cable.

[0012] S6: Write a second user-defined unit and a third user-defined unit, the second user-defined unit is used to realize the real-time calculation and application of the pneumatic load, and the third user-defined unit is used to read the displacement motion state of the connection end of the emergency cable and the wire, and determine the application method of the load at the tightening end of the cable;

[0013] S7: Analysis of conductor galloping characteristics after installation of emergency cables: Based on the aerodynamic loads obtained in S1 and the galloping analysis model including the emergency cables established in S5, the galloping characteristics after installation of the emergency cables are analyzed. The galloping characteristics after installation of the emergency cables include the starting time, frequency, order and galloping amplitude parameters of the conductor galloping.

[0014] S8: Emergency cable anti-dancing assessment: Compare the dancing characteristics of the conductor before and after the installation of the emergency cable, and analyze the anti-dancing effect of the emergency cable.

[0015] Furthermore, the ice aerodynamic load in step S1 specifically includes lift, drag and torque coefficients, and the aerodynamic load calculation formula is:

[0016]

[0017] Where FL is the aerodynamic lift, FD is the aerodynamic drag, M is the aerodynamic torque, and ρ air is the air density, U z is the wind speed, d is the diameter of the bare conductor, α is the wind attack angle, and the value range of α is 0-360 degrees. i (α)(i=L, D, M) is the aerodynamic coefficient that varies with the angle of attack measured in the wind tunnel test.

[0018] Furthermore, α is an integer multiple of 5 degrees between 0 and 360 degrees, the initial value of α is 0 degrees, and every 5 degrees is analyzed as a working condition. A total of 72 analysis models are established, and the wire aerodynamic parameter curves of the 72 models are obtained respectively. The aerodynamic coefficients of the 72 models are obtained by high-order function fitting, which can save the number of modeling. When the value of α is not an integer multiple of 5 degrees, linear interpolation is used to calculate the aerodynamic coefficient of the corresponding wind attack angle.

[0019] Furthermore, the custom subroutine written in S3 reads the torsion angle of each conductor section in real time, uses the aerodynamic load calculation formula to calculate the aerodynamic load of the conductor at the current moment and applies it, thereby realizing the numerical simulation of line galloping.

[0020] Furthermore, in step S5, the number of emergency cables installed is consistent with the number of waveforms, and the installation position of the emergency cables is at the dancing wave crest. In the finite element software, a coupling connection is adopted between the node at the conductor wave crest and the typical point on the ground to simulate the connection form of the emergency cables.

[0021] Furthermore, in S6, the second user-defined unit is a non-rigidity, massless beam unit that shares a node with the conductor. The corresponding subroutine reads the torsion angle of the conductor in the current state and combines it with the aerodynamic load obtained by numerical simulation to complete the application of the aerodynamic load of the conductor at the current moment.

[0022] Furthermore, in S6, the third user-defined unit shares a node with the emergency cable and is also a beam unit without stiffness and mass. In the corresponding subroutine, the displacement data of the node at the connection end of the cable and the wire is read to determine the movement state of the wire. If the wire moves upward, a downward pulling force is applied to the tightening end of the emergency cable to suppress the movement of the wire; if the wire moves downward, the tightening end of the emergency cable is kept stationary, thereby simulating the complete cable tightening process.

[0023] Compared with the prior art, the numerical simulation method for dynamic cable control for emergency stopping of transmission line provided by the present invention has the following beneficial effects:

[0024] The present invention provides a numerical simulation method for dynamic cable control for emergency anti-dancing of power transmission lines, which first calculates the aerodynamic load of ice-covered conductors at any angle; then establishes a finite element model of the conductor without the emergency cable installed; writes a first user-defined unit and a user-defined program that can apply the aerodynamic load in real time, which are used to implement the application of the real-time aerodynamic load according to the wind attack angle of the conductor, and realize the numerical simulation of the line dancing; according to the numerical simulation of the line dancing, the conductor dancing characteristics can be obtained; according to the conductor dancing characteristics, in the finite element software, an emergency cable is applied to the dancing crest position; writes a second user-defined unit and a third user-defined unit, the second user-defined unit can implement the real-time application of the aerodynamic load according to the conductor angle, and the third user-defined unit is used to read the displacement motion state of the emergency cable and the conductor connection end, determine the application method of the cable tightening end load, and finally compares the dancing characteristics of the conductor before and after the installation of the emergency cable, and analyzes and obtains the anti-dancing effect of the emergency cable.

[0025] The numerical simulation method for dynamic cable control for emergency anti-dancing of transmission lines provided by the present invention realizes accurate simulation analysis of the dancing characteristics of the emergency device installed during the line dancing process and accurate evaluation of the anti-dancing efficiency, providing theoretical and data support for line emergency disposal. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0027] Figure 1 A schematic flow chart of a numerical simulation method for dynamic cable control for emergency arrest of transmission line provided by the present invention. DETAILED DESCRIPTION

[0028] The present invention is further described below in conjunction with the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Please refer to Figure 1 , Figure 1 A schematic flow chart of a numerical simulation method for dynamic cable control for emergency arrest of transmission line provided by the present invention.

[0030] The present invention provides a numerical simulation method for dynamic cable control for emergency stopping of power transmission lines, comprising the following steps:

[0031] S1: Determine the aerodynamic load of ice-covered conductors: Use numerical simulation methods to determine the aerodynamic load of ice-covered conductors under wind attack angles ranging from 0 to 360 degrees.

[0032] In some preferred embodiments, the icing aerodynamic load specifically includes lift, drag and torque coefficients, and the aerodynamic load calculation formula is:

[0033]

[0034] Where FL is the aerodynamic lift, FD is the aerodynamic drag, M is the aerodynamic torque, and ρ air is the air density, U z is the wind speed, d is the diameter of the bare conductor, α is the wind attack angle, and the value range of α is 0-360 degrees. i (α)(i=L,D,M) is the aerodynamic coefficient that varies with wind angle of attack measured in wind tunnel tests.

[0035] To calculate the aerodynamic load using this method, it is necessary to first calculate the aerodynamic coefficient at any angle between 0 and 360 degrees, and it is necessary to establish an analysis model for any angle, which makes the calculation difficult. In some preferred embodiments, α is an integer multiple of 5 degrees between 0 and 360 degrees, and the initial value of α is 0 degrees. Every 5 degrees is analyzed as a working condition, and a total of 72 analysis models are established, which reduces the number of analysis models established. Then, the wire aerodynamic parameter curves of the 72 models are obtained respectively, and the aerodynamic coefficients of the 72 models are obtained by high-order function fitting, which can save the number of modeling. When the value of α is not an integer multiple of 5 degrees, linear interpolation is used to calculate the aerodynamic coefficient of the corresponding wind attack angle.

[0036] S2: Establish a finite element model of a typical line segment: Establish a finite element analysis model of the line that includes the conductor and spacer structure information.

[0037] S3: Write the first user-defined unit and the user-defined subroutine for applying the aerodynamic load, realize the real-time calculation and application of the aerodynamic load, and realize the numerical simulation of the line galloping.

[0038] Specifically, the custom subroutine written in S3 reads the torsion angle of each conductor section in real time, uses the aerodynamic load calculation formula to calculate the aerodynamic load of the conductor at the current moment and applies it, thereby realizing the numerical simulation of line galloping.

[0039] S4: Analysis of wire galloping characteristics: Through the aerodynamic load obtained in S1 and the finite element model established in S2, combined with the first user-defined unit and the custom subroutine in S3, the wire galloping characteristics are analyzed. The wire galloping characteristics include the start time, frequency, order and galloping amplitude parameters of the wire galloping.

[0040] S5: Establish a dancing analysis model including the emergency cable: Based on the conductor dancing characteristics obtained in S4, the emergency cable is installed at the conductor dancing crest, and a finite element model including the emergency cable is established. Based on the conductor dancing period and dancing amplitude, a periodically changing tensioning force is applied to the emergency cable to simulate the dynamic tightening process of the emergency cable.

[0041] In step S5, the number of emergency cables installed is consistent with the number of waveforms. The installation position of the emergency cables is at the dancing wave crest. In the finite element software, a coupling connection is adopted between the node at the conductor wave crest and the typical point on the ground to simulate the connection form of the emergency cables.

[0042] S6: Write the second user-defined unit and the third user-defined unit. The second user-defined unit is used to realize the real-time calculation and application of the pneumatic load. The third user-defined unit is used to read the displacement movement state of the emergency cable and the wire connection end, and determine the application method of the load at the tightening end of the cable.

[0043] In some preferred embodiments, the second user-defined unit is a stiffness-free, massless beam unit that shares a node with the conductor. The corresponding subroutine completes the application of the conductor aerodynamic load at the current moment by reading the conductor's current state torsion angle and combining it with the aerodynamic load obtained by numerical simulation.

[0044] The third user-defined unit shares a node with the emergency cable and is also a beam unit without stiffness and mass. In the corresponding subroutine, the displacement data of the node at the connection end of the cable and the wire is read to determine the movement state of the wire. If the wire moves upward, a downward pulling force is applied to the tightening end of the emergency cable to suppress the movement of the wire; if the wire moves downward, the tightening end of the emergency cable is kept stationary, thereby simulating the complete cable tightening process.

[0045] S7: Analysis of conductor galloping characteristics after installation of emergency cables: Based on the aerodynamic loads obtained in S1 and the galloping analysis model including the emergency cables established in S5, the galloping characteristics after installation of the emergency cables are analyzed. The galloping characteristics after installation of the emergency cables include the starting time, frequency, order and galloping amplitude parameters of the conductor galloping.

[0046] S8: Emergency cable anti-dancing assessment: Compare the dancing characteristics of the conductor before and after the installation of the emergency cable, and analyze the anti-dancing effect of the emergency cable.

[0047] The present invention provides a numerical simulation method for dynamic cable control for emergency anti-dancing of power transmission lines, which first calculates the aerodynamic load of ice-covered conductors at any angle; then establishes a finite element model of the conductor without the emergency cable installed; writes a first user-defined unit and a user-defined program that can apply the aerodynamic load in real time, which are used to implement the application of the real-time aerodynamic load according to the wind attack angle of the conductor, and realize the numerical simulation of the line dancing; according to the numerical simulation of the line dancing, the conductor dancing characteristics can be obtained; according to the conductor dancing characteristics, in the finite element software, an emergency cable is applied to the dancing crest position; writes a second user-defined unit and a third user-defined unit, the second user-defined unit can implement the real-time application of the aerodynamic load according to the conductor angle, and the third user-defined unit is used to read the displacement motion state of the emergency cable and the conductor connection end, determine the application method of the cable tightening end load, and finally compares the dancing characteristics of the conductor before and after the installation of the emergency cable, and analyzes to obtain the anti-dancing effect of the emergency cable.

[0048] The numerical simulation method for dynamic cable control for emergency anti-dancing of transmission lines provided by the present invention realizes accurate simulation analysis of the dancing characteristics of the emergency device installed during the line dancing process and accurate evaluation of the anti-dancing efficiency, providing theoretical and data support for line emergency disposal.

[0049] At this point, those skilled in the art should recognize that, although multiple exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived based on the content disclosed in the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all these other variations or modifications.

Claims

1. A numerical simulation method for dynamic cable control for emergency arrest of transmission line, characterized in that: The simulation method comprises the following steps: S1: Determine the aerodynamic load of iced conductors: Use numerical simulation methods to determine the aerodynamic load of iced conductors under wind attack angles ranging from 0 to 360 degrees; S2: Establish a finite element model of a typical line segment: Establish a finite element analysis model of the line that includes the conductor and spacer structure information; S3: writing a first user-defined unit and a user-defined subroutine for applying aerodynamic loads, realizing real-time calculation and application of aerodynamic loads, and realizing numerical simulation of line galloping; S4: Wire galloping feature analysis: Through the aerodynamic load obtained in S1 and the finite element model established in S2, combined with the first user-defined unit and the custom subroutine in S3, the wire galloping features are analyzed, and the wire galloping features include the start time, frequency, order and galloping amplitude parameters of the wire galloping; S5: Establish a galloping analysis model including the emergency cable: Based on the conductor galloping characteristics obtained in S4, an emergency cable is installed at the conductor galloping wave crest, and a finite element model including the emergency cable is established. Based on the conductor galloping period and galloping amplitude, a periodically changing tensioning force is applied to the emergency cable to simulate the dynamic tightening process of the emergency cable. S6: Write a second user-defined unit and a third user-defined unit, the second user-defined unit is used to realize the real-time calculation and application of the pneumatic load, and the third user-defined unit is used to read the displacement motion state of the connection end of the emergency cable and the wire, and determine the application method of the load at the tightening end of the cable; S7: Analysis of conductor galloping characteristics after installation of emergency cables: Based on the aerodynamic loads obtained in S1 and the galloping analysis model including the emergency cables established in S5, the galloping characteristics after installation of the emergency cables are analyzed. The galloping characteristics after installation of the emergency cables include the starting time, frequency, order and galloping amplitude parameters of the conductor galloping. S8: Emergency cable anti-dancing assessment, compare the dancing characteristics of the conductor before and after the installation of the emergency cable, and analyze the anti-dancing effect of the emergency cable.

2. A numerical simulation method for dynamic cable control for emergency arrest of transmission line according to claim 1, characterized in that: The ice-covered aerodynamic load in step S1 specifically includes lift, drag and torque coefficients, and the aerodynamic load calculation formula is: Where FL is the aerodynamic lift, FD is the aerodynamic drag, M is the aerodynamic torque, and ρ air is the air density, U z is the wind speed, d is the diameter of the bare conductor, α is the wind attack angle, and the value range of α is 0-360 degrees. i (α)(i=L, D, M) is the aerodynamic coefficient that varies with the angle of attack measured in the wind tunnel test.

3. A numerical simulation method for dynamic cable control for emergency stopping of transmission line according to claim 2, characterized in that: α is an integer multiple of 5 degrees between 0 and 360 degrees. The initial value of α is 0 degrees. Every 5 degrees is analyzed as a working condition. A total of 72 analysis models are established, and the wire aerodynamic parameter curves of the 72 models are obtained respectively. The aerodynamic coefficients of the 72 models are obtained by high-order function fitting, which can save the number of modeling. When the value of α is not an integer multiple of 5 degrees, linear interpolation is used to calculate the aerodynamic coefficient of the corresponding wind attack angle.

4. A numerical simulation method for dynamic cable control for emergency stopping of transmission line according to claim 3, characterized in that: The custom subroutine written in S3 reads the torsion angle of each conductor section in real time, uses the aerodynamic load calculation formula to calculate the aerodynamic load of the conductor at the current moment and applies it, realizing the numerical simulation of line galloping.

5. A numerical simulation method for dynamic cable control for emergency arrest of transmission line according to claim 4, characterized in that: In step S5, the number of emergency cables installed is consistent with the number of waveforms. The installation position of the emergency cables is at the dancing wave crest. In the finite element software, a coupling connection is adopted between the node at the conductor wave crest and the typical point on the ground to simulate the connection form of the emergency cables.

6. A numerical simulation method for dynamic cable control for emergency arrest of transmission line according to claim 5, characterized in that: In S6, the second user-defined unit is a non-stiffness, non-mass beam unit that shares a node with the conductor. The corresponding subroutine reads the torsion angle of the conductor in the current state and combines it with the aerodynamic load obtained by numerical simulation to complete the application of the aerodynamic load of the conductor at the current moment.

7. A numerical simulation method for dynamic cable control for emergency arrest of transmission line according to claim 6, characterized in that: In S6, the third user-defined unit shares a node with the emergency cable and is also a beam unit without stiffness and mass. In the corresponding subroutine, the displacement data of the node at the connection end of the cable and the wire is read to determine the movement state of the wire. If the wire moves upward, a downward pulling force is applied to the tightening end of the emergency cable to suppress the movement of the wire; if the wire moves downward, the tightening end of the emergency cable is kept stationary to simulate the complete cable tightening process.

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