CN-120914686-B - Gas insulation rigid power transmission line with spiral supporting structure and optimization method thereof

Abstract

The invention provides a novel gas-insulated rigid power transmission line with a spiral supporting structure and an optimization method thereof, wherein the gas-insulated rigid power transmission line comprises three supporting insulators which are axially separated along a conductor and have a radial angle difference of 120 degrees along the conductor; the high-voltage conductor, the grounding shell, the high-voltage side/grounding side metal insert, the spiral metal ring and the roller. Compared with the original structure, the invention utilizes the spiral metal ring and the roller, thereby effectively improving the assembly convenience. The triangular support structure is improved to be stable, the mechanical strength and stability of the triangular support structure are remarkably improved, the possible inclination and fracture risks of three single support insulators caused by unbalanced stress are avoided, and conductor supports with different GIL arrangement angles can be met. The novel spiral supporting insulator is structurally designed, so that the electric field and stress of the insulating supporting insulator are effectively reduced, the insulating performance of the insulating supporting insulator is improved, and the reliability of safe operation of a power transmission line is improved.

Inventors

• DONG JIANAN
• DU BOXUE
• LIANG HUCHENG
• LI JUNCHEN

Assignees

• 天津大学

Dates

Publication Date

20260512

Application Date

20250708

Claims (3)

1. 1. A gas-insulated rigid power transmission line with a spiral supporting structure comprises supporting insulators (1), (2) and (3), wherein the three supporting insulators (1), (2) and (3) are separated along the axial direction of a conductor and are different in radial angle by 120 degrees along the conductor, a high-voltage conductor (4), a grounding shell (5), a high-voltage side metal insert (9) and a grounding side metal insert (8), a spiral metal ring (6) connected with the three grounding side metal inserts (8), and rollers (7) mounted in gaps between the spiral metal ring (6) and the grounding shell (5) and assist the three supporting insulators (1), (2) and (3) and the high-voltage conductor (4) to be synchronously pushed into a GIL shell.
2. 2. The optimization method of the gas-insulated rigid power transmission line with the spiral supporting structure according to claim 1, wherein the optimization design is performed on the shape parameters of the insulating piece, so as to realize the electric field-stress cooperative regulation and control of the supporting insulator, and the optimization method comprises the following steps: Firstly, establishing a geometric model of a gas-insulated rigid transmission line of a novel spiral supporting structure based on SOLIWORKS finite element software, and parameterizing an insulator structure; Step two: ① Establishing an electric field control equation The current continuity equation is used to calculate the electric field distribution at dc voltage as follows: wherein E is a DC steady-state electric field, and gamma is the conductivity of the insulating material; The boundary condition is that the potential of the high-voltage conductor is set to 800kV, and the shell is grounded; setting the conductivity and the relative dielectric constant of the materials of each component; ② Establishing a mechanical stress control equation Assuming that the material is linear elastic, the stress and strain can be solved by the following equation: Wherein F v is the bulk force exerted on the HV conductor, σ is the stress tensor, v is the strain tensor, Y is the Young's modulus of the dielectric material, G is the shear modulus of the material; Boundary conditions, namely setting the load of the high-voltage conductor as 6 times of gravity, and setting the metal insert as fixed constraint; setting the density, young's modulus and Poisson's ratio of the materials of each part; ③ Calculation of electric field and stress Solving an electric field and stress control equation by adopting COMSOL, and calculating the maximum internal electric field strength and the maximum mechanical stress; Step three: ① Setting constraint conditions And (3) shape parameter constraint, namely in the electric field finite element analysis model of the support insulator established in the step one, a control variable method is used to enable the shape parameter to be optimized to change within a certain range, an objective function is calculated when the parameter changes, and the change range of the optimized shape parameter is shown as the following formula: Wherein x 1 is the radius of the top of the support, x 2 is the radius of the bottom of the support, r 1 is the chamfer of the top of the support, r 2 is the chamfer of the bottom of the support, x 3 is the radius of the insert, h 3 is the depth of the insert, r 3 is the chamfer of the insert, the subscript is min for the minimum value of each shape parameter, and the subscript is max for the maximum value of each shape parameter; The performance index constraint conditions are as follows: Wherein E tmax is the maximum surface electric field of the support insulator, and sigma max is the maximum mechanical stress of the support insulator; ② Calculating an objective function With the maximum internal electric field intensity and the maximum mechanical stress reduced as optimization targets, the objective function expression is as follows: Wherein E imax supports the maximum internal electric field of the insulator, E i0max is the maximum internal electric field of the initial structure support insulator, sigma max is the maximum mechanical stress of the support insulator, and sigma 0max is the maximum mechanical stress of the initial structure support insulator; Calculating an objective function by using E imax and sigma max of the insulator in the second step; Step three: And (3) optimizing the shape parameters of the insulator by adopting a genetic algorithm according to the constraint conditions in the step two, so as to minimize the objective function and obtain the optimal shape parameters under the corresponding optimized objective function.
3. 3. The optimization method according to claim 2, wherein the third step is as follows: 1) Firstly, randomly generating m insulators with different shapes under the constraint of shape parameters; 2) Calculating the objective function of each support insulator according to the second step, judging whether the performance index constraint in the second step is met, and setting the objective function of the insulator which is not met as 10; 3) Selecting insulators with smaller objective functions in the initial population preferentially; 4) Selecting two insulators, randomly selecting and exchanging shape parameters of the insulators, wherein the crossing probability is p, so that a brand new individual offspring is created; 5) Mutation, namely randomly changing the shape parameter of the offspring, wherein the mutation probability is q, and obtaining a new individual; 6) Calculating objective functions of all the updated insulators, setting the objective functions of the insulators which do not meet constraint conditions as 10, and recording the overall optimal result and the local optimal result; 7) Repeating the steps 3) to 6) until the maximum iteration number n is reached or the objective function remains unchanged after a plurality of iterations; 8) And finally outputting the individual parameter combination with the lowest objective function value and meeting all constraint conditions as an optimal design scheme of the insulator structure, and storing a corresponding optimized single-support insulator model result.

Description

Gas insulation rigid power transmission line with spiral supporting structure and optimization method thereof Technical Field The invention belongs to the field of computational electricity and mechanics, relates to a novel ultra-high voltage GIL support insulator structure design method, and particularly relates to a gas insulation rigid power transmission line with a spiral support structure and an optimization method thereof. Background The gas insulated power transmission line (GIL) is a metal-encapsulated power transmission device, and is widely applied to power systems due to the advantages of high reliability, strong environmental adaptability, no secondary pollution and the like. The supporting insulator widely used in GIL mainly plays a role of insulation and support, and the insulation performance of the supporting insulator determines the safety and stability of GIL to a great extent. However, in recent years, breakdown explosion faults frequently occur in the operation process of the three-support insulator, and the safety of the whole power transmission system is seriously threatened. And the insulator is subjected to a strong electric field and large mechanical stress in a complex environment, which is an important cause of insulation breakdown fault. The structural design of the insulator is a direct means for directly homogenizing an electric field and reducing stress. The conventional single support insulator GIL structure is shown in fig. 1, wherein 1 is a support insulator, 2 is a ground side insert, 3 is a high voltage side insert, 4 is a high voltage conductor, and 5 is a ground shell. The traditional single support insulator is arranged right below the high-voltage conductor and is fixed with the shell through a screw at the grounding insert. The conventional single support insulator structure has the following problems: 1. The traditional insulator is fixed at the shell through the grounding side insert, the conductors can deviate from the center of the GIL pipeline in the installation process of the three single-support insulators in the same direction, so that the stress of the three insulators is unbalanced, and 2, the weight of the GIL conductors and mechanical stress generated by expansion caused by heat and contraction caused by cold cause possible inclination and fracture risks of the three single supports in the same direction. 3. The single support insulator is only suitable for fixed insulators and is difficult to meet for occasions needing sliding insulators. 4. The conventional support insulator can only provide support in a vertical direction, and is applicable to only GIL wires arranged horizontally. The actual GIL placement angle varies from location to location, including, for example, vertically placed GILs where conventional single support insulators are difficult to support. Therefore, development of a novel support insulator is needed to realize electric field-stress cooperative regulation and control of the insulator and reduce the risk of explosion breakdown of the insulator. Disclosure of Invention How to improve the insulation of the insulator is a problem to be solved by the person skilled in the art. In order to solve the problems, the invention provides a gas-insulated rigid power transmission line with a spiral supporting structure, which comprises supporting insulators 1, 2 and 3, wherein the three supporting insulators are axially separated along a conductor, the radial angle of the supporting insulators is different by 120 degrees along the conductor, a high-voltage conductor 4, a grounding shell 5, high-voltage side/grounding side metal inserts 8 and 9, which play roles in connecting the supporting insulators with the conductor/shell and reducing the electric field at the tail end of the insulator, a spiral metal ring 6, which plays a role in connecting the three grounding metal inserts and guaranteeing the equipotential of the three metal inserts, and a roller 7, which is arranged in a gap between the spiral metal ring and the grounding shell, can assist the three insulators and the conductor to be synchronously pushed into a GIL shell, so that the assembly convenience is effectively improved. In addition, in order to improve the insulation performance of the support insulator, the invention adopts an optimization algorithm to optimally design the shape parameters of the novel insulator, realizes the electric field-stress cooperative regulation and control of the support insulator, and comprises the following steps: Step one: Establishing a geometric model of the gas-insulated rigid transmission line of the novel spiral supporting structure based on SOLIWORKS finite element software, and parameterizing an insulator structure; Step two: ① Establishing an electric field control equation The current continuity equation is used to calculate the electric field distribution at dc voltage as follows: Wherein E is a DC steady-state electric field, and gamma is