Method and system for electric power evaluation of a split-type gas insulated transmission line

Abstract

The application belongs to the technical field of power transmission line operation and maintenance, aims to solve the problems of being unable to accurately calculate the size of the circulating current of each phase GIL metal shell and being unable to simulate the total average electric power of each phase GIL, and discloses a split type gas insulated power transmission line electric power evaluation method and system, which calculates the corrected magnetic flux in each phase GIL metal shell according to the conductor current of each phase GIL and the circulating current of each phase GIL metal shell, substitutes the obtained corrected magnetic flux, performs cyclic iteration, and obtains the circulating current value of the GIL metal shell after the mutual inductance between each phase GIL conductor and the metal shell is stable when the calculation error between the upper and lower two times of the circulating current in each phase GIL metal shell is less than 0.1%, fully considers the influence of the magnetic field generated by the three-phase circulating current on the circulating current of a certain phase, and realizes the accurate calculation of the size of the circulating current of each phase GIL metal shell. The application can accurately evaluate the total average electric power of each phase GIL conductor and metal shell under power frequency and each harmonic.

Description

Technical Field

[0001] This application belongs to the field of power transmission line operation and maintenance technology, and in particular relates to a method and system for evaluating the electrodynamics of a split-type gas-insulated power transmission line. Background Technology

[0002] Gas-insulated transmission lines (GILs) are a new type of power transmission method that is generally unaffected by environmental factors such as harsh weather and special terrain. Moreover, the electrical characteristics of GILs are similar to those of overhead lines (OHLs), and their transmission capacity is usually greater than that of cable lines of the same voltage level. They also have low power loss and are suitable for high elevation differences.

[0003] The gas-insulated barrier (GIL) structure mainly consists of an outer shell and a central conductor, secured by an insulator. Basin-type insulators on both sides seal the internal SF6 insulating gas. The single-phase GIL conductor has a large current-carrying capacity, generating a significant magnetic field in space. Because the metal shell is grounded, a large circulating current is generated within the GIL shell. The direction and magnitude of the electrodynamic forces acting on the conductors and shell differ between different phases of the GIL. Furthermore, the surge in conductor current during a single-phase short-circuit fault results in a tremendous short-circuit electrodynamic force on the conductor and metal shell. Therefore, accurate calculation of the circulating current magnitude within the metal shell of each phase of the GIL and the electrodynamic forces acting on the conductors and metal shell is crucial.

[0004] Currently, most methods for calculating GIL circulation current use approximate analytical methods, neglecting the influence of the magnetic field generated by the three-phase circulation on the circulation of a certain phase, making it impossible to accurately calculate the magnitude of the circulation current in each phase of the GIL metal shell. In GIL electrodynamic analysis, multiphysics (magnetic-circuit coupling) finite element simulation modeling is used to calculate the distribution of electrodynamic stress (unit: Newton / square meter) on the surface of the GIL conductor and metal shell. However, for actual three-phase GIL structures, the length of each standard straight element is 10 to 12 meters. During three-phase modeling and simulation, the large size of the actual GIL pipeline, the complex internal structure, and different laying methods all cause the simulation calculation results to fail to converge after mesh subdivision. Due to the application of alternating excitation, the server system faces extremely high simulation difficulty in the transient study of multiphysics fields, especially for large-size, complex structures and multi-field coupling. At the same time, the current in the GIL conductor is not a monotonic sinusoidal change and there are multiple harmonic interferences. If the influence of harmonics is considered at the excitation point, it will further increase the convergence difficulty of the solver during iterative calculation, and it will be impossible to simulate the total average electrodynamic force (in Newtons) on the GIL pipeline in each fixed interval. Summary of the Invention

[0005] The purpose of this application is to provide a method and system for evaluating the electrodynamic forces of split-type gas-insulated transmission lines, which solves the problems of being unable to accurately calculate the circulating current magnitude of the metal shell of each phase GIL and being unable to simulate the total average electrodynamic force on each phase GIL.

[0006] To achieve the above objectives, this application provides the following technical solution:

[0007] In a first aspect, this application provides a method for evaluating the electrodynamic performance of a split-type gas-insulated transmission line, including:

[0008] S1. Based on the structural dimensions of the GIL pipeline, calculate the self-inductance of each phase GIL conductor and metal shell in the split-type GIL linear unit model.

[0009] S2. Based on the self-inductance of each phase GIL conductor and metal shell and the spatial relationship between each phase GIL pipeline, calculate the magnetic flux in each phase GIL metal shell under the influence of the current of each phase GIL conductor only.

[0010] S3. Calculate the mutual inductance between the GIL conductor and the metal shell in each phase based on the magnetic flux in the metal shell of each phase and the current in the GIL conductor of each phase.

[0011] S4. Calculate the circulating current value in the metal casing of each phase of the GIL according to the T-type equivalent method of the hollow coil;

[0012] S5. Calculate the corrected magnetic flux in the GIL metal shell of each phase based on the current in each phase GIL conductor and the circulating current in each phase GIL metal shell.

[0013] S6. Substitute the corrected magnetic flux obtained in S5 into S3, and perform a cyclic iteration from S3 to S5 to obtain the circulating current value of the GIL metal shell after the mutual inductance between the GIL conductor and the metal shell in each phase is stabilized.

[0014] S7. By leveraging the coupling relationship of the spatial magnetic field, establish electrodynamic calculation models for each phase of the GIL conductor and the metal shell.

[0015] S8. Calculate the maximum current value of the actual GIL conductor under power frequency and each harmonic. Repeat S2 to S7 to obtain the electrodynamic force of each phase GIL conductor and metal shell under power frequency and each harmonic.

[0016] As an feasible approach, in S1, the split-type GIL linear unit model is a GIL linear unit model with three-phase horizontal laying and grounded at both ends.

[0017] As an feasible approach, the formula for calculating the self-inductance of the GIL conductor and the metal casing in S1 is as follows:

[0018]

[0019] In the formula, L Ad For the self-inductance of phase A conductor, L Bd For the self-inductance of phase B conductor, L CdLet r be the self-inductance of the C-phase conductor, μ0 be the permeability of free space, l be the length of the outer shell, h be the distance between the metal outer shell and the ground, r1 be the inner radius of the GIL conductor, and r2 be the outer radius of the GIL conductor.

[0020]

[0021] In the formula, L Ak For the self-inductance of phase A casing, L Bk For the self-inductance of phase B casing, L Ck Let r be the self-inductance of the C-phase shell, μ0 be the permeability of free space, l be the length of the shell, h be the distance between the metal shell and the ground, r3 be the inner radius of the GIL shell, and r4 be the outer radius of the GIL shell.

[0022] As an feasible approach, in S2, the formula for calculating the magnetic flux in each phase of the GIL metal shell is as follows:

[0023]

[0024]

[0025] In the formula, Ψ AA Ψ AB Ψ AC Ψ represents the magnetic flux formed by the currents in phases A, B, and C in the metal casing of phase A. BA Ψ BB Ψ BC Ψ represents the magnetic flux formed by the currents in phases A, B, and C in the metal casing of phase B. CA Ψ CB Ψ CC These represent the magnetic fluxes (I) generated by phases A, B, and C conductors within the phase C metal casing. A I B I C Let represent the current inductances in phases A, B, and C, respectively; μ0 be the permeability of free space; l be the length of the GIL metal casing; h be the distance between the metal casing and ground; r3 be the inner radius of the GIL metal casing; r4 be the outer radius of the GIL metal casing; and S be the current inductance in phases A, B, and C, respectively. 1d The distance S between two adjacent conductors 2d ρ represents the distance between two non-adjacent conductors, and ρ is the distance calculated by integration.

[0026] As an feasible approach, in S3, the formula for calculating the mutual inductance between the three-phase GIL conductors and the metal casing is as follows:

[0027] M A =ψ AA / I A +ψ AB / IB +ψ AC / I C ≈ψ A / I A ≈(ψ AA +ψ AB +ψ AC ) / I A

[0028] M B =ψ BA / I A +ψ BB / I B +ψ BC / I C ≈ψ B / I B ≈(ψ BB +ψ BA +ψ BC ) / I B

[0029] M C =ψ CA / I A +ψ CB / I B +ψ CC / I C ≈ψ C / I C ≈(ψ CA +ψ CB +ψ CC ) / I C

[0030] In the formula, M A M B M C The mutual inductance Ψ between the magnetic fields generated by the currents in the three phase conductors A, B, and C is respectively shown. AA Ψ AB Ψ AC These represent the magnetic flux generated by the currents in phases A, B, and C in the metal casing of phase A, measured in Weber (Ψ). BA Ψ BB Ψ BC Ψ represents the magnetic flux formed by the currents in phases A, B, and C in the metal casing of phase B. CA Ψ CB Ψ CC I represents the magnetic flux generated by the currents in phases A, B, and C in the metal casing of phase C, respectively. A I B I C These represent the currents in phase conductors A, B, and C, respectively.

[0031] As an feasible approach, in S4, the formula for calculating the circulating current value in the GIL metal casing of each phase is as follows:

[0032]

[0033] In the formula, M A Z represents the mutual inductance between the A-phase GIL conductor and the metal casing. A1 Let Z be the impedance of phase A's casing. j1 Z j2 I represents the grounding impedance at both ends. A The current intensity of phase A conductor is given.

[0034] As an feasible approach, in S5, the formula for calculating the corrected magnetic flux in the GIL metal shell of each phase is as follows:

[0035]

[0036]

[0037] In the formula, Ψ * AB Ψ * AC Let Ψ be the corrected magnetic flux generated by the circulating currents in the B and C phase metal shells within the A phase metal shell, respectively. * BA Ψ * BC Let Ψ be the corrected magnetic flux generated by the circulating currents in the A and C phase metal shells within the B phase metal shell, respectively. * CA Ψ * CB I represents the corrected magnetic flux generated by the circulating currents in the A and B phase metal shells within the C phase metal shell, respectively. Ak I Bk I Ck These are the effective values ​​of the circulating current in the metal casings of phases A, B, and C, respectively, and their directions are opposite to the current in the conductors.

[0038] As an feasible approach, the electrodynamic calculation model in S7 is as follows:

[0039]

[0040] In the formula, F Admax F Bdmax F Cdmax The maximum electromotive force F is the maximum force exerted on the three phase conductors A, B, and C of the GIL. Akmax F Bkmax F Ckmax These represent the maximum electrodynamic forces (I) acting on the A, B, and C phase metal casings of the GIL. AmaxI Bmax I Cmax These represent the maximum current values ​​in phase conductors A, B, and C, respectively, I. Akmax I Bkmax I Ckmax Let r1, r2, and r3 be the maximum circulating currents of the metal casing after the mutual inductance of A, B, and C has stabilized, and their directions are opposite to the currents in the conductors. Let S be the outer radius of the GIL conductor. 1k The average distance S between two adjacent metal casings 2k It represents the average distance between two non-adjacent metal casings.

[0041] As an feasible approach, in S6, when the calculation error between the two calculations of the circulating current in each phase GIL metal shell is less than 0.1%, the circulating current value of the GIL metal shell after the mutual inductance between each phase GIL conductor and the metal shell is stabilized is obtained.

[0042] Secondly, this application provides a split-type gas-insulated transmission line electrodynamic evaluation system, comprising:

[0043] The model building module is used to build a split GIL linear unit model and calculate the self-inductance of each phase conductor and metal shell according to the structural dimensions of the GIL pipeline.

[0044] The initial magnetic flux calculation module is used to calculate the initial magnetic flux of each phase metal shell based on the self-inductance of each phase conductor and shell and the spatial relationship between the pipes.

[0045] The mutual inductance calculation module is used to calculate the mutual inductance value between each phase conductor and the metal shell based on the initial magnetic flux and conductor current.

[0046] The circulation calculation module is used to calculate the circulation value of each phase of the metal casing;

[0047] The flux correction module is used to recalculate the corrected flux of each phase of the metal casing based on the conductor current and circulating current value.

[0048] The iterative convergence module is used to repeatedly execute the mutual inductance calculation, circulation current calculation and magnetic flux correction steps until the error between two adjacent circulation current values ​​is less than 0.1%, and outputs the circulation current result after the mutual inductance is stabilized.

[0049] The electrodynamic modeling module is used to establish electrodynamic calculation models of each phase conductor and shell based on the stable circulation value and through the spatial magnetic field coupling relationship;

[0050] The harmonic analysis module is used to obtain the maximum value of the power frequency and harmonic current of the actual conductor through the power quality analyzer, and drive the initial magnetic flux calculation module to the electrodynamic modeling module to perform multi-band electrodynamic calculations.

[0051] Thirdly, this application provides an electronic device, including a memory and a processor, wherein the memory stores computer-readable instructions, and the processor executes the computer-readable instructions to implement the described electrodynamic evaluation method for split-type gas-insulated transmission lines.

[0052] Fourthly, this application provides a computer-readable storage medium storing computer-readable instructions, which, when executed, implement the described electrodynamic evaluation method for split-type gas-insulated transmission lines.

[0053] Compared with existing technologies, the electrodynamic evaluation method and system for split-type gas-insulated transmission lines provided in this application have the following advantages:

[0054] Based on the current in each phase GIL conductor and the circulating current in each phase GIL metal shell, the corrected magnetic flux in each phase GIL metal shell is calculated. The corrected magnetic flux obtained in S5 is substituted into S3, and S3 to S5 are iterated repeatedly. When the calculation error between the two calculations of the circulating current in each phase GIL metal shell is less than 0.1%, the circulating current value of the GIL metal shell after the mutual inductance between each phase GIL conductor and the metal shell is stabilized is obtained. The influence of the magnetic field generated by the three-phase circulating current on the circulating current of a certain phase is fully considered, and the accurate calculation of the circulating current magnitude of each phase GIL metal shell is realized.

[0055] Based on the accurately calculated circulating current values ​​of the GIL metal shells of each phase, and utilizing the coupling relationship of the spatial magnetic field, an electrodynamic calculation model for each phase GIL conductor and metal shell is established. This enables accurate evaluation of the total average electrodynamic force of each phase GIL conductor and metal shell in a split-type gas-insulated transmission line. This overcomes the problem that due to the application of alternating excitation, the server system faces extremely high simulation difficulty for large-size and complex structures under transient research in multiphysics fields, making it impossible to simulate and obtain the total average electrodynamic force of each phase GIL conductor and metal shell.

[0056] Measure the maximum current value of the actual GIL conductor under power frequency and each harmonic, repeat S2 to S7, to accurately evaluate the total average electrodynamic force of each phase GIL conductor and metal shell under power frequency and each harmonic. Attached Figure Description

[0057] To more clearly illustrate the technical solution of this application, the accompanying drawings used in the technical description will be briefly introduced below.

[0058] Figure 1 A flowchart of the electrodynamic evaluation method for split-type gas-insulated transmission lines provided in this application;

[0059] Figure 2 A schematic diagram of electromagnetic induction of the GIL casing for the electrodynamic evaluation method of the split gas-insulated transmission line provided in this application;

[0060] Figure 3 A simplified equivalent circuit diagram of circulating current in the casing of a split gas-insulated transmission line provided in this application for the electrodynamic evaluation method of the split gas-insulated transmission line;

[0061] Figure 4 Harmonic waveform diagram of the electrodynamic evaluation method for the split-type gas-insulated transmission line provided in this application;

[0062] Figure 5 A schematic diagram of the structure of the split-type gas-insulated transmission line electrodynamic evaluation system provided in this application. Detailed Implementation

[0063] The following detailed description provides further details on specific implementation methods.

[0064] like Figures 1 to 4 As shown, this application provides a method for evaluating the electrodynamic performance of a split-type gas-insulated transmission line, comprising the following steps:

[0065] S1. Establish a split-type GIL linear unit model, and calculate the self-inductance of each phase GIL conductor and metal shell according to the structural dimensions of the GIL pipeline.

[0066] S2. Based on the self-inductance of each phase GIL conductor and metal shell and the spatial relationship between each phase GIL pipeline, calculate the magnetic flux in each phase GIL metal shell, considering only the influence of the current of each phase GIL conductor.

[0067] S3. Calculate the mutual inductance between the GIL conductor and the metal shell in each phase based on the magnetic flux in the metal shell of each phase and the current in the GIL conductor of each phase.

[0068] S4. Based on the mutual inductance between the GIL conductor and the metal shell, conductor current, shell impedance and grounding resistance obtained in S3, calculate the circulating current value in the metal shell of each phase of the GIL according to the existing T-type equivalent method of hollow coil.

[0069] S5. Calculate the corrected magnetic flux in the GIL metal shell of each phase based on the current in each phase GIL conductor and the circulating current in each phase GIL metal shell.

[0070] S6. Substitute the corrected magnetic flux obtained in S5 into S3 and perform a cyclic iteration from S3 to S5. When the calculation error between the two iterations of the circulating current in each phase of the GIL metal shell is less than 0.1%, the circulating current value of the GIL metal shell after the mutual inductance between each phase of the GIL conductor and the metal shell is stabilized is obtained.

[0071] S7. Based on the circulating current value of the GIL metal shell after mutual inductance stabilization obtained in S6, an electrodynamic calculation model of each phase GIL conductor and metal shell is established using the coupling relationship of the spatial magnetic field.

[0072] S8. Calculate the maximum current value of the actual GIL conductor under power frequency and harmonics by using a power quality analyzer. Repeat S2 to S7 to obtain the electrodynamic force of each phase GIL conductor and metal shell under power frequency and harmonics.

[0073] In S1, the linear element model is a common model, which is established according to the actual pipeline laying method.

[0074] In S1, the split-type GIL linear element model is a three-phase horizontally laid GIL linear element model with both ends grounded. If it is a three-phase vertically laid GIL, only the algorithm for calculating the magnetic flux needs to be changed. Taking phase A as an example, the magnetic flux generated by phases B and C in phase A shell and ground is calculated by adding the distance between phase A and phase B conductors to the upper and lower limits of the integral for phase B, and adding the distance between phase A and phase C conductors to the upper and lower limits of the integral for phase C.

[0075] Based on the structural dimensions of the GIL piping, such as Figure 2 As shown, the calculation method for obtaining the self-inductance values ​​of the GIL conductor and metal casing by S1 is as follows:

[0076]

[0077] In the formula, L Ad The self-inductance of phase A conductor, unit: Henry; L Bd The self-inductance of phase B conductor, unit: Henry; L Cd The self-inductance of the C-phase conductor is expressed in Henry; μ0 is the permeability of free space, μ0 = 4π × 10⁻⁶. –7 Henry / meter; l is the length of the outer casing, in meters; h is the distance between the metal casing and the ground, in meters; r1 is the inner radius of the GIL conductor, in meters; r2 is the outer radius of the GIL conductor, in meters.

[0078]

[0079] In the formula, L Ak The self-inductance of phase A casing, unit: Henry; L Bk The self-inductance of the B-phase casing, unit: Henry; L Ck The self-inductance of the C-phase shell is expressed in Henry; μ0 is the permeability of free space, μ0 = 4π × 10⁻⁶. –7 Henry / meter; l is the length of the outer shell, in meters; h is the distance between the metal outer shell and the ground, in meters; r3 is the inner radius of the GIL outer shell, in meters; r4 is the outer radius of the GIL outer shell, in meters.

[0080] In S2, the method for calculating the magnetic flux in the GIL metal shell of each phase is as follows:

[0081]

[0082] In the formula, Ψ AA Ψ AB Ψ AC Ψ represents the magnetic flux formed by the currents in phases A, B, and C in the metal casing of phase A. BA Ψ BB Ψ BC Ψ represents the magnetic flux formed by the currents in phases A, B, and C in the metal casing of phase B. CA Ψ CB Ψ CC These represent the magnetic fluxes (I) generated by phases A, B, and C conductors within the phase C metal casing. A I B I C Let μA be the current intensity in phase conductors A, B, and C, respectively, and μ0 be the permeability of free space, μ0 = 4π × 103 –7 Henry / meter; l is the length of the GIL metal casing, h is the distance between the metal casing and the ground, r3 is the inner radius of the GIL metal casing, r4 is the outer radius of the GIL metal casing, S 1d The distance S between two adjacent conductors 2d ρ represents the distance between two non-adjacent conductors, and ρ is the distance calculated by integration.

[0083] In S3, the method for calculating the mutual inductance between the three-phase GIL conductors and the metal casing is as follows:

[0084] M A =ψ AA / I A +ψ AB / I B +ψ AC / I C ≈ψ A / I A ≈(ψ AA +ψ AB +ψ AC ) / I A

[0085] M B =ψ BA / I A +ψ BB / I B +ψ BC / I C ≈ψ B / I B ≈(ψ BB +ψ BA +ψ BC ) / I B

[0086] M C =ψCA / I A +ψ CB / I B +ψ CC / I C ≈ψ C / I C ≈(ψ CA +ψ CB +ψ CC ) / I C

[0087] In the formula, M A M B M C The mutual inductance Ψ between the magnetic fields generated by the currents in the three phase conductors A, B, and C is respectively shown. AA Ψ AB Ψ AC These represent the magnetic flux generated by the currents in phases A, B, and C in the metal casing of phase A, measured in Weber (Ψ). BA Ψ BB Ψ BC These represent the magnetic flux generated by the currents in phases A, B, and C in the metal casing of phase B, measured in Weber (Ψ). CA Ψ CB Ψ CC These represent the magnetic flux generated in the metal casing of phase C by the currents in phases A, B, and C, respectively, measured in Weber (I). A I B I C These are the currents in phases A, B, and C, respectively, effective values ​​at a power frequency of 50 Hz, in amperes.

[0088] In S4, the method for calculating the circulating current value in the GIL metal shell of each phase is as follows:

[0089] Based on the principle of the equivalent circuit of a current transformer and the principle of a two-port network, the spatial mutual inductance model is simplified to a T-type circuit. Taking phase A as an example, the model is simplified equivalently without considering the busbar: ignoring the load impedance ZL, which is relatively large compared to the grounding impedance, and combining the mutual inductance between the GIL conductor and the metal casing obtained from S3, the conductor current, the casing impedance, and the grounding impedance, the formula for calculating the circulating current intensity of phase A casing is as follows:

[0090]

[0091] In the formula, M A Z represents the mutual inductance between the A-phase GIL conductor and the metal casing. A1 The impedance of phase A is the casing impedance; Z j1 Z j2 The grounding impedance at both ends; I A The current intensity of phase A conductor is given.

[0092] The derivation steps of this formula are as follows: based on Figure 3 The simplified equivalent circuit diagram of the A-phase casing circulating current of the GIL is shown below:

[0093] I A =I1+I2

[0094] I1(Z A1 -M A +Z j1 ) = (I A -I1)(M A +Z j2 / / Z L )≈(I A -I1)(M A +Z j2 )

[0095] I1(Z A1 -M A +Z j1 ) = I A (M A +Z j2 )

[0096]

[0097] Due to the load impedance Z L The load impedance Z is relatively large compared to the grounding resistance. L Negligible, the formula for calculating the A-phase shell circulation of GIL can be further simplified to:

[0098] I1 is the circulating current generated by the A-phase casing, which is I AK Similarly, I can be calculated. BK and I CK .

[0099] In S5, the method for calculating the corrected magnetic flux in the GIL metal shell of each phase is as follows:

[0100]

[0101] In the formula, Ψ * AB Ψ * AC Let Ψ be the corrected magnetic flux generated by the circulating currents in the B and C phase metal shells within the A phase metal shell, respectively. * BA Ψ * BC These represent the corrected magnetic flux generated in the phase B metal shell by the circulating currents of phases A and C, respectively; Ψ * CA Ψ *CB I represents the corrected magnetic flux generated by the circulating currents in the A and B phase metal shells within the C phase metal shell, respectively. Ak I Bk I Ck These are the effective values ​​of the circulating current in the metal casings of phases A, B, and C, respectively, and their directions are opposite to the current in the conductors.

[0102] Substituting the corrected magnetic flux obtained in S5 into S3, the method for calculating the mutual inductance between each phase GIL conductor and the metal shell is as follows:

[0103]

[0104] In the formula, M * A M * B M * C The mutual inductance values ​​between the three-phase conductor currents (A, B, and C) and the magnetic fields generated by the circulating currents in the adjacent phase metal casings are respectively coupled together. Using the recalculated mutual inductance values ​​between each phase GIL conductor and the metal casing, the circulating current intensity in the casing is calculated again. When the calculation error between the two calculations of the circulating current in each phase GIL metal casing is less than 0.1%, the circulating current value of the GIL metal casing after the mutual inductance between each phase GIL conductor and the metal casing is stabilized is obtained.

[0105] In S7, the process of establishing the electrodynamic calculation model of each phase GIL conductor and metal shell is as follows: based on the circulating current value of the GIL metal shell after mutual inductance stabilization obtained in S6, the electrodynamic calculation model of each phase GIL conductor and metal shell is established by utilizing the coupling relationship of the spatial magnetic field.

[0106] Based on the circulating current value of the GIL metal shell after mutual inductance stabilization obtained in S6, the method for establishing the electrodynamic calculation model of each phase GIL conductor and metal shell in S7 is as follows:

[0107] The electromotive force on a phase A conductor of a certain length needs to be considered in two parts: first, the influence of the currents in phase B and phase C conductors on its electromotive force; and second, the influence of the metal shells in phase B and phase C on its electromotive force. It is necessary to clarify the distances between phase B and phase C conductors and phase A conductors, as well as the distances between phase B and phase C metal shells and phase A conductors, and to calculate the electromotive force for each. The electromotive force reaches its maximum value at the phase ωt = nπ + 75°. The calculation method for the electromotive force on phase C conductors is the same as that for phase A conductors. For phase B conductors, the maximum electromotive force occurs only at the phase ωt = nπ + 75° or nπ + 165° due to the difference in the phases of the three-phase currents.

[0108] Similarly, the electrodynamic force on the phase A metal shell needs to be considered in two parts: first, the influence of the currents of phase B and phase C conductors on the electrodynamic force generated by them; and second, the influence of the phase B and phase C metal shells on the electrodynamic force generated by them. It is necessary to clarify the distance between phase B and phase C conductors and phase A metal shell, as well as the distance between phase B and phase C metal shells and phase A metal shell.

[0109] Considering the maximum value obtained after considering the phase angle difference of the three-phase currents in the conductor, the electrodynamic calculation model can be expressed as:

[0110]

[0111] In the formula, F Admax F Bdmax F Cdmax The maximum electromotive force F is the maximum force exerted on the three phase conductors A, B, and C of the GIL. Akmax F Bkmax F Ckmax These represent the maximum electrodynamic forces acting on the A, B, and C phase metal casings of the GIL; I Amax I Bmax I Cmax These represent the maximum current values ​​in phases A, B, and C, respectively; I Akmax I Bkmax I Ckmax , respectively, represent the maximum circulating current of the metal casing after the mutual inductance of A, B, and C has stabilized, and their directions are opposite to the current in the conductor; r2 is the outer radius of the GIL conductor, S 1k The average distance S between two adjacent metal casings 2k It represents the average distance between two non-adjacent metal casings.

[0112] In one embodiment, taking a horizontally arranged single-section 500kV GIL pipeline as an example, its metal outer shell has an outer diameter of 0.49 meters and an inner diameter of 0.48 meters; the conductor's outer diameter is 0.16 meters and the conductor's inner diameter is 0.14 meters; the spacing between adjacent conductors is 1 meter; the height of the center conductor of each phase GIL relative to the ground grid is 1.5 meters; the characteristic frequencies of each harmonic are 150 Hz, 250 Hz, and 350 Hz, and the waveforms of each harmonic are as follows: Figure 4 As shown. The grounding impedance is 0.01 ohms, the length of a single section of the GIL conduit is 12 meters, and there is a fixed constraint every 4 meters.

[0113] A large current is converted into a measurable small current using a current transformer, and the three-phase current is synchronously sampled using a power quality analyzer. The maximum current value of each phase conductor current in the GIL is obtained as follows: 5000 amps at 50 Hz power frequency; 120 amps at 150 Hz third harmonic; 70 amps at 250 Hz fifth harmonic; and 40 amps at 350 Hz seventh harmonic. Following steps S1 to S6 of the method according to this invention, the circulating current in the metal casing of phase A can be calculated as follows: [The remaining text appears to be incomplete and requires further context for accurate translation.] The maximum current is 2400 amps, the maximum current at 150 Hz under the 3rd harmonic is 72 amps, the maximum current at 250 Hz under the 5th harmonic is 25 amps, and the maximum current at 350 Hz under the 7th harmonic is 13 amps; the circulating current in the metal casing of phase B is as follows: the maximum current at 50 Hz is 2750 amps, the maximum current at 150 Hz under the 3rd harmonic is 95 amps, the maximum current at 250 Hz under the 5th harmonic is 56 amps, and the maximum current at 350 Hz under the 7th harmonic is 31 amps; the circulating current in the metal casing of phase C is the same as that of phase A.

[0114] Based on actual testing of the circulating current in the casing of the 500kV GIL pipeline, Fourier decomposition of the circulating current in the metal casing revealed the following values ​​for phases A and C: a maximum current of 2370 amps at 50 Hz power frequency, a maximum current of 65 amps at 150 Hz third harmonic, a maximum current of 21 amps at 250 Hz fifth harmonic, and a maximum current of 16 amps at 350 Hz seventh harmonic; and for phase B: a maximum current of 2880 amps at 50 Hz power frequency, a maximum current of 75 amps at 150 Hz third harmonic, a maximum current of 24 amps at 250 Hz fifth harmonic, and a maximum current of 18 amps at 350 Hz seventh harmonic. Comparative calculations show that the calculation error of the circulating current in the metal casing of phases A and C at power frequency is 1.26%, and the calculation error of the circulating current in the metal casing of phase B is 4.5%. Therefore, the method provided in this application can effectively calculate the magnitude of the circulating current in the metal casing of each phase of the GIL, thereby realizing the analytical calculation of the electromotive force on the conductors and metal casing of each phase of the GIL.

[0115] Calculate the maximum electrodynamic forces per section at power frequency for a three-phase horizontally arranged GIL pipe. The maximum electrodynamic forces per section at power frequency for each phase are as follows: Phase A conductor 4.47 N, Phase A metal casing 3.43 N, Phase B conductor 6.38 N, Phase B metal casing 2.15 N, Phase C conductor 4.47 N, Phase C metal casing 3.43 N; the maximum electrodynamic forces per section at third harmonic frequency are as follows: Phase A conductor 0.4 × 10⁻⁶ N / A. -3 The Newtonian, A-phase metal casing withstands 1.1 × 10⁻⁶. -3 The Newtonian, B-phase conductor withstands 2.08 × 10⁻⁶. -3 The Newtonian, B-phase metal casing withstands 1.21 × 10⁻⁶.-3 A Newtonian, C-phase conductor can withstand 0.4 × 10⁻⁶ Ω·cm. -3 The Newtonian, C-phase metal casing withstands 1.1 × 10⁻⁶ Ω·cm. -3 Newton; the maximum electromotive force under the fifth harmonic is as follows: the conductor in phase A withstands 0.16 × 10⁻⁶. -3 The Newtonian, A-phase metal casing withstands 1.59 × 10⁻⁶. -3 A Newtonian, B-phase conductor can withstand 1.79 × 10⁻⁶ Ω·cm. -3 The Newtonian, B-phase metal casing withstands 0.27 × 10⁻⁶. -3 A Newtonian, C-phase conductor can withstand 0.16 × 10⁻⁶ Ω·cm. -3 The Newtonian, C-phase metal casing withstands 1.59 × 10⁻⁶. -3 Newton; the maximum electromotive force under the seventh harmonic is as follows: the conductor in phase A withstands 0.02 × 10⁻⁶. -3 The Newtonian, A-phase metal casing withstands 0.55 × 10⁻⁶. -3 The Newtonian, B-phase conductor withstands 0.64 × 10⁻⁶. -3 The Newtonian, B-phase metal casing withstands 0.07 × 10⁻⁶. -3 A Newtonian, C-phase conductor can withstand 0.02 × 10⁻⁶ Ω·cm. -3 The Newtonian, C-phase metal casing withstands 0.55 × 10⁻⁶. -3 Newton. Under actual operating conditions, the maximum current value of the actual GIL conductor under power frequency and each harmonic can be calculated by a power quality analyzer. Steps S2 to S7 are executed to obtain the electrodynamic force of each phase GIL conductor and metal shell under power frequency and each harmonic.

[0116] During a single-phase short-circuit fault, a surge in current within phase A conductor significantly increases the electrodynamic forces on all phase GIL conductors and the metal casing. This invention's method can rapidly calculate the magnitude of the short-circuit electrodynamic forces on each phase conductor and casing based on measurements of the current within the conductor during a single-phase short circuit. This overcomes the significant challenges of simulating large-size, complex structures in multi-physics transient studies of server systems due to alternating excitation, and the inability to simulate the total average electrodynamic force of each phase GIL conductor and metal casing due to harmonic interference.

[0117] Furthermore, based on the above method, this application also provides a split-type gas-insulated transmission line electrodynamic evaluation system, such as... Figure 5 As shown, it includes:

[0118] The model building module is used to build a split GIL linear unit model and calculate the self-inductance of each phase conductor and metal shell according to the structural dimensions of the GIL pipeline.

[0119] The initial magnetic flux calculation module is used to calculate the initial magnetic flux of each phase of the metal shell based on the self-inductance of each phase conductor and the shell and the spatial relationship between the pipes, while only considering the influence of conductor current.

[0120] The mutual inductance calculation module is used to calculate the mutual inductance value between each phase conductor and the metal shell based on the initial magnetic flux and conductor current.

[0121] The circulating current calculation module is used to calculate the circulating current value of each phase of the metal shell by combining mutual inductance value, conductor current, shell impedance and grounding resistance through the T-type equivalent method of hollow coil;

[0122] The flux correction module is used to recalculate the corrected flux of each phase of the metal casing based on the conductor current and circulating current value.

[0123] The iterative convergence module is used to repeatedly execute the mutual inductance calculation, circulation current calculation and magnetic flux correction steps until the error between two adjacent circulation current values ​​is less than 0.1%, and outputs the circulation current result after the mutual inductance is stabilized.

[0124] The electrodynamic modeling module is used to establish electrodynamic calculation models of each phase conductor and shell based on the stable circulation value and through the spatial magnetic field coupling relationship;

[0125] The harmonic analysis module is used to obtain the maximum value of the power frequency and harmonic current of the actual conductor through the power quality analyzer, and drive the initial magnetic flux calculation module to the electrodynamic modeling module to perform multi-band electrodynamic calculations.

[0126] The split-type gas-insulated transmission line electrodynamic evaluation system provided in the above embodiments can realize the technical solutions described in the above method embodiments. The specific implementation principles of each module can be found in the corresponding content in the above method embodiments, and will not be repeated here.

[0127] In addition, this application also provides an electronic device, including a memory and a processor, wherein the memory stores computer-readable instructions, and the processor executes the computer-readable instructions to implement the above-described method.

[0128] In addition, this application also provides a computer-readable storage medium storing computer-readable instructions, which, when executed, implement the above-described method.

[0129] Computer-readable media, including both permanent and non-permanent, removable and non-removable media, can store information using any method or technology. Information can be computer-readable instructions, data structures, program modules, or other data.

[0130] The above description is only a specific embodiment of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application.

Claims

1. A method for evaluating the electrodynamic performance of a split-type gas-insulated transmission line, characterized in that, include: S1. Based on the structural dimensions of the GIL pipeline, calculate the self-inductance of each phase GIL conductor and metal shell in the split-type GIL linear unit model. S2. Based on the self-inductance of each phase GIL conductor and metal shell and the spatial relationship between each phase GIL pipeline, calculate the magnetic flux in each phase GIL metal shell under the influence of the current of each phase GIL conductor only. S3. Calculate the mutual inductance between the GIL conductor and the metal shell in each phase based on the magnetic flux in the metal shell of each phase and the current in the GIL conductor of each phase. S4. Calculate the circulating current value in the GIL metal casing for each phase; the formula for calculating the circulating current value in the GIL metal casing for each phase is as follows: In the formula, M A This represents the mutual inductance between the A-phase GIL conductor and the metal casing. Z A1 The impedance of phase A is the casing impedance. Z j1 , Z j2 The grounding impedance at both ends is... I A The current intensity of phase A conductor; S5. Based on the current in each phase of the GIL conductor and the circulating current in each phase of the GIL metal casing, calculate the corrected magnetic flux in each phase of the GIL metal casing; the formula for calculating the corrected magnetic flux in each phase of the GIL metal casing is as follows: In the formula, Ψ * AB , Ψ * AC These represent the corrected magnetic flux generated in the phase A metal shell by the circulating currents of phases B and C, respectively. Ψ * BA , Ψ * BC These represent the corrected magnetic flux generated in the phase B metal shell by the circulating currents of phases A and C, respectively. Ψ * CA , Ψ * CB These represent the corrected magnetic flux generated in the phase C metal shell by the circulating currents in the phase A and phase B metal shells, respectively. I Ak , I Bk , I Ck These are the effective values ​​of the circulating current in the metal casings of phases A, B, and C, respectively, and their directions are opposite to the current in the conductors. S6. Substitute the corrected magnetic flux obtained in S5 into S3, and perform a cyclic iteration from S3 to S5 to obtain the circulating current value of the GIL metal shell after the mutual inductance between the GIL conductor and the metal shell in each phase is stabilized. S7. By leveraging the coupling relationship of the spatial magnetic field, establish electrodynamic calculation models for each phase of the GIL conductor and the metal shell. S8. Calculate the maximum current value of the actual GIL conductor under power frequency and each harmonic. Repeat S2~S7 to obtain the electrodynamic force of each phase GIL conductor and metal shell under power frequency and each harmonic.

2. The electrodynamic evaluation method for split-type gas-insulated transmission lines according to claim 1, characterized in that, In S1, the formula for calculating the self-inductance of the GIL conductor and the metal casing is as follows: In the formula, L Ad For the self-inductance of phase A conductor, L Bd For the self-inductance of phase B conductor, L Cd For the self-inductance of the C-phase conductor, μ 0 represents the permeability of free space. l The length of the outer shell, h This is the distance between the metal casing and the ground. r 1 represents the inner radius of the GIL conductor. r 2 represents the outer radius of the GIL conductor; In the formula, L Ak For the self-inductance of phase A's outer shell, L Bk For the self-inductance of the B-phase shell, L Ck For the self-inductance of the C-phase casing, μ 0 represents the permeability of free space. l The length of the outer shell, h This is the distance between the metal casing and the ground. r 3 represents the inner radius of the GIL casing. r 4 represents the outer radius of the GIL casing.

3. The electrodynamic evaluation method for split-type gas-insulated transmission lines according to claim 1, characterized in that, In S2, the formula for calculating the magnetic flux in the GIL metal shell of each phase is as follows: In the formula, Ψ AA , Ψ AB , Ψ AC These represent the magnetic flux generated by the currents in phases A, B, and C within the metal casing of phase A. Ψ BA , Ψ BB , Ψ BC These represent the magnetic flux generated by the currents in phases A, B, and C in the metal casing of phase B. Ψ CA , Ψ CB , Ψ CC These represent the magnetic fluxes generated by phases A, B, and C within the phase C metal casing, respectively. I A , I B , I C These represent the current intensities in phases A, B, and C, respectively. μ 0 represents the permeability of free space. l The length of the GIL metal casing. h This is the distance between the metal casing and the ground. r 3 represents the inner radius of the GIL metal casing. r 4 represents the outer radius of the GIL metal casing. S 1d The distance between two adjacent conductors, S 2d The distance between two non-adjacent conductors. ρ The distance is calculated by integration.

4. The electrodynamic evaluation method for split-type gas-insulated transmission lines according to claim 1, characterized in that, In S3, the formula for calculating the mutual inductance between the three-phase GIL conductors and the metal casing is as follows: In the formula, M A , M B , M C The mutual inductance values ​​between the metal shells are the magnetic fields generated by the currents in the three phase conductors A, B, and C. Ψ AA , Ψ AB , Ψ AC These represent the magnetic flux generated by the currents in phases A, B, and C in the metal casing of phase A, respectively, in Weber. Ψ BA , Ψ BB , Ψ BC These represent the magnetic flux generated by the currents in phases A, B, and C in the metal casing of phase B. Ψ CA , Ψ CB , Ψ CC These represent the magnetic flux generated by the currents in phases A, B, and C within the metal casing of phase C. I A , I B , I C These represent the currents in phase conductors A, B, and C, respectively.

5. The electrodynamic evaluation method for split-type gas-insulated transmission lines according to claim 1, characterized in that, In S7, the electrodynamic calculation model is as follows: In the formula, F Admax , F Bdmax , F Cdmax These represent the maximum electrodynamic forces acting on the A, B, and C phase conductors of the GIL, respectively. F Akmax , F Bkmax , F Ckmax These represent the maximum electrodynamic forces acting on the A, B, and C phase metal casings of the GIL. I Amax , I Bmax , I Cmax These represent the maximum current values ​​in phase conductors A, B, and C, respectively. I Akmax , I Bkmax , I Ckmax These represent the maximum circulating current values ​​of the metal casing after the mutual inductance of A, B, and C has stabilized, and their directions are opposite to the current in the conductor. r 2 represents the outer radius of the GIL conductor. S 1k The average distance between two adjacent metal casings. S 2k It represents the average distance between two non-adjacent metal casings.

6. A split-type gas-insulated transmission line electrodynamic evaluation system, characterized in that, Based on the electrodynamic evaluation method for split-type gas-insulated transmission lines as described in any one of claims 1-5, the system comprises: The model building module is used to build a split GIL linear unit model and calculate the self-inductance of each phase conductor and metal shell according to the structural dimensions of the GIL pipeline. The initial magnetic flux calculation module is used to calculate the initial magnetic flux of each phase metal shell based on the self-inductance of each phase conductor and shell and the spatial relationship between the pipes. The mutual inductance calculation module is used to calculate the mutual inductance value between each phase conductor and the metal shell based on the initial magnetic flux and conductor current. The circulation calculation module is used to calculate the circulation value of each phase of the metal casing; The flux correction module is used to recalculate the corrected flux of each phase of the metal casing based on the conductor current and circulating current value. The iterative convergence module is used to repeatedly execute the mutual inductance calculation, circulation current calculation and magnetic flux correction steps until the error between two adjacent circulation current values ​​is less than 0.1%, and outputs the circulation current result after the mutual inductance is stabilized. The electrodynamic modeling module is used to establish electrodynamic calculation models of each phase conductor and shell based on the stable circulation value and through the spatial magnetic field coupling relationship; The harmonic analysis module is used to obtain the maximum value of the power frequency and harmonic current of the actual conductor through the power quality analyzer, and drive the initial magnetic flux calculation module to the electrodynamic modeling module to perform multi-band electrodynamic calculations.

7. An electronic device, characterized in that, It includes a memory and a processor, the memory storing computer-readable instructions, and the processor executing the computer-readable instructions to implement the electrodynamic evaluation method for split gas-insulated transmission lines as described in any one of claims 1-5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-readable instructions, which, when executed, implement the electrodynamic evaluation method for split-type gas-insulated transmission lines as described in any one of claims 1-5.

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