Alternating current GIS insulator metal particle inhibition method based on surface fluorination

Abstract

The invention relates to an alternating current GIS insulator metal particle inhibition method based on surface fluorination, which changes the surface appearance of an insulator and the surface electric field distribution of an insulating material under an alternating current electric field by performing fluorination modification treatment on the surface of the insulator so as to regulate and control the motion behavior of charged particles around the insulator. Through electric field calculation and stress analysis, the motion characteristics of metal particles near the insulator are simulated, the metal particles with different particle sizes are released at different positions of the inner surface of the GIS grounding shell, the change of the motion characteristics of the metal particles is evaluated, and the fluorinated insulator effectively inhibits the activity of the metal particles and inhibits the adsorption effect of the insulator on the nearby metal particles. The method can effectively inhibit the insulator in the GIS from adsorbing nearby metal particles, prevents insulation failure accidents, improves the reliability and stability of high-voltage electrical equipment, and has the advantages of simple operation process, industrialization, easy realization, universality and the like.

Description

Technical Field

[0001] The present invention belongs to the field of high voltage equipment manufacturing, and specifically relates to a method for suppressing the movement of metal particles in AC GIS insulators based on fluorination modification, the purpose of which is to improve the reliability of AC GIS equipment operation and ensure the safe and stable operation of the transmission system. Background Art

[0002] Gas-insulated metal-enclosed switchgear (GIS) has rapidly become the preferred technical solution for large power hubs due to its compact structure, high reliability, and excellent environmental adaptability. As the core component of GIS equipment, the basin insulator has the functions of mechanical support, isolation of gas chamber, and electrical insulation. However, in recent years, with the miniaturization and compactness of GIS equipment, basin insulator surface discharge failures have occurred frequently, especially when there are metal particles near the basin insulator. The particles move in the GIS and eventually adhere to the surface of the insulator, resulting in increased electric field distortion and shortened insulation distance, which can easily cause insulation failures.

[0003] In order to limit the attachment of metal particles on the surface of AC GIS insulators and improve the insulation performance of the system, the common technologies currently include adding particle traps near the insulators, coating the electrode surface, and installing driving electrodes. However, the above methods are insufficient in terms of long-term stability, convenience of installation and maintenance, and economic benefits, and have not completely eliminated the potential threat of metal particles to the equipment. The fluorination modification of insulators mainly modifies the surface chemical structure of the insulator surface material, changes the surface morphology of the insulator and the distribution of the electric field along the surface of the insulating material under the AC electric field, so as to achieve the regulation of the movement behavior of charged particles around the insulator. This method has the advantages of simple operation process, industrialization, easy implementation, and universality. Summary of the invention

[0004] Based on the above problems, the purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for suppressing metal particles in AC GIS insulators based on surface fluorination.

[0005] To achieve the above-mentioned purpose, the present invention provides a method for suppressing metal particles in AC GIS insulators based on surface fluorination, in which the chemical structure of the surface material of the insulator is modified through fluorination modification, the surface morphology of the material and the AC electric field distribution are changed, the movement characteristics of charged metal particles near the insulator are regulated, and the adsorption of metal particles by the insulator is suppressed.

[0006] The technical solution proposed by the present invention is a method for inhibiting the movement activity of metal particles in AC GIS insulators based on fluorination modification, which method comprises the following steps:

[0007] Step 1: Construct an AC GIS basin insulator model, build a simulation calculation model for the electrostatic field inside the GIS, and simulate and calculate the electric field distribution of the insulator under AC voltage based on the simulation model;

[0008] Step 2: construct a fluorinated modified insulator model and modify the relevant dielectric parameters of the insulator model;

[0009] Step 3: Combined with the electric field distribution of the GIS pipeline obtained in step 2, the force of the metal particles is analyzed and a motion model of the metal particles in the pipeline is established;

[0010] Step 4: Release metal particles of different sizes at different locations on the inner surface of the GIS shell, and observe the effects of uniform insulators and fluorinated insulators on the movement characteristics of the metal particles.

[0011] Furthermore, the insulator model in step 1 is a 500 kV AC GIS pot-type insulator, and other model areas include coaxially arranged high-voltage conductors and grounded casings, insulating gas, and the like.

[0012] Furthermore, in step 1, the outer radius of the GIS coaxial conductor is set to 80-100 mm, and the inner diameter of the grounding shell is set to 250-300 mm.

[0013] Furthermore, in step 1, the material of the high-voltage conductor and the grounding shell is aluminum alloy, the insulator material is epoxy resin / aluminum oxide composite material, and the insulating gas is sulfur hexafluoride.

[0014] Furthermore, in step 1, the relative dielectric constants of the uniform insulator and the sulfur hexafluoride gas are set to 5-7 and 1-3 respectively.

[0015] Furthermore, in step 1, the high-voltage conductor of the model is connected to an AC voltage of 500 kV and 50 Hz, the metal casing is grounded, and the sulfur hexafluoride gas pressure inside the GIS is 0.5-0.7 MPa.

[0016] Furthermore, after the fluorination modification treatment of the insulator in step 2, the relative dielectric constant of the surface area thereof decreases to 2-3, preferably 2.5-2.7, and the dielectric parameters of other model parts remain unchanged.

[0017] Furthermore, in step three, the particle motion model of the metal particles in the AC electric field takes into account the effects of the electric field force, gravity, electric field gradient force and gas resistance on the metal particles.

[0018] Furthermore, in step 4, the releasing of metal particles at different positions on the inner surface of the GIS shell refers to releasing metal particles at different distances from the surface of the insulator, and the releasing distances are 10, 20, and 30 mm respectively.

[0019] Furthermore, in step 4, the metal particles with different particle sizes released on the inner surface of the GIS shell refer to spherical metal particles with different diameters, and the particle sizes of the metal particles are 0.1, 0.2, and 0.4 mm respectively.

[0020] Compared with the prior art, the beneficial effects brought about by the present invention are: it can weaken the adsorption effect of the basin-type insulator in GIS on nearby metal particles, inhibit the movement activity of metal particles, and prevent insulation failure accidents caused by the adsorption of metal particles on the surface of the insulator. It is of great significance to solve the problem of metal particle pollution of high-voltage electrical equipment and improve the operating reliability of equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The simulation model of 500kV AC GIS and pot-type insulator: (a) internal structure diagram; (b) cross-sectional diagram;

[0022] Figure 2 Schematic diagram of AC electric field distribution and metal particle release position of GIS insulator;

[0023] Figure 3 To release the motion characteristics of metal particles at different locations near the uniform insulator;

[0024] Figure 4 To release the motion characteristics of metal particles of different sizes near a uniform insulator;

[0025] Figure 5 To investigate the motion characteristics of metal particles released at different locations near the fluorinated insulator;

[0026] Figure 6 To release the motion characteristics of metal particles of different sizes near the fluorinated insulator;

[0027] Figure 7 The axial forces on metal particles near uniform and fluorinated insulators: (a) uniform insulator; (b) fluorinated insulator. DETAILED DESCRIPTION

[0028] How the present invention is implemented is further described below in conjunction with the accompanying drawings and specific embodiments.

[0029] A method for suppressing the activity of metal particles in AC GIS insulators comprises the following steps:

[0030] Step 1: Construct a 500kV AC GIS pot-type insulator model, as shown in the attached figure. Figure 1As shown in the figure, the high-voltage conductor is coaxially arranged with the grounded shell and parallel to the horizontal plane. The pot insulator is located between the conductor and the shell, and plays the role of electrical insulation and mechanical support in the GIS device. Based on the GIS internal electrostatic field simulation method, the electric field distribution near the GIS insulator is calculated under 500kV power frequency AC voltage. The conductor voltage in the model is shown as follows:

[0031]

[0032] Where U m is the AC voltage peak value, f is the voltage frequency, 50Hz, is the initial phase and t is the time.

[0033] As attached Figure 2 As shown, the electric field distribution results show that under AC voltage, due to the mismatch between the dielectric parameters of the insulation structure and the material interface, the electric field distribution is highly uneven, and serious electric field distortion occurs at the triple junction.

[0034] Step 2: Combined with the AC electric field distribution of the GIS insulator calculated in step 1, a charging motion model of metal particles inside the GIS is established. The metal particles are charged after colliding with the grounded shell, and the charge can be calculated by the following formula:

[0035]

[0036] In the formula, ε 0 With ε r are vacuum and relative dielectric constant respectively, d is the particle size of spherical metal particles, E is the electric field strength at the location of the metal particles, and considering the Coulomb force, gravity, buoyancy, electric field gradient force and gas resistance on the metal particles, the motion trajectory of the metal particles under the transient action of the AC electric field is calculated. The force conditions of the metal particles are shown in the following table:

[0037] Table 1 Expression of metal particle stress

[0038]

[0039] Spherical metal particles with a particle size of 0.2 mm were released at different positions on the ground electrode surface to simulate the motion characteristics of charged metal particles and the uniform insulator on the metal particles. The effect of the uniform insulator on the motion of the particles is shown in the attached figure. Figure 3 As shown. Under the action of AC voltage, the metal particles show a wave-like jump, move toward the insulator and finally adsorb on the surface of the insulator. When released at different positions, the metal particles will move toward the insulator. On this basis, spherical metal particles of different sizes are released at the same position on the grounding electrode surface (10mm away from the insulator surface) to simulate the motion characteristics of charged metal particles and uniform insulators on metal particles. The effect of uniform insulators on particle motion is shown in the attached figure. Figure 4 The particle size of metal particles affects the charge and force of the particles. As the particle size of metal particles increases, the jumping height decreases, and the particles tend to move toward the surface of the insulator and eventually adhere to the surface of the insulator.

[0040] Step 3: Surface fluorination treatment is performed on the insulator to change the surface chemical structure of the insulating material and reduce the relative dielectric constant of the composite material. Similar to step 2, the effect of the fluorinated insulator on the motion characteristics of metal particles at different locations and with different particle sizes is calculated. Figure 5 With attached Figure 6 The results of the metal particle movement show that after the surface fluorination treatment, the particle movement activity is weakened, and the movement of particles with different particle sizes is always confined to a small area nearby, and no longer moves to the surface of the insulator and adsorbs, which effectively reduces the damage of metal particles to the insulation performance. The axial force of metal particles when released near the two insulators is analyzed, as shown in the attached figure. Figure 7 As shown, the metal particles near the uniform insulator are subjected to fluctuating forces toward the surface of the insulator, which eventually causes the metal particles to move and adhere. The change in the dielectric parameters of the fluorinated insulator changes the electric field distribution, the axial force is reduced, and the direction is changed, thereby effectively suppressing the adsorption of the insulator on the metal particles.

Claims

1. A method for suppressing metal particles in AC GIS insulators based on surface fluorination, characterized in that: The following steps are involved: Step 1: Construct an AC GIS basin insulator model, build a simulation calculation model for the electrostatic field inside the GIS, and simulate and calculate the electric field distribution of the insulator under AC voltage based on the simulation model; Step 2: construct a fluorinated modified insulator model and modify the relevant dielectric parameters of the insulator model; Step 3: Combined with the electrostatic field distribution of the GIS pipeline obtained in step 2, the force of the metal particles is analyzed and a motion model of the metal particles in the pipeline is established; Step 4: Release metal particles of different sizes at different locations on the inner surface of the GIS shell, and observe the effects of uniform insulators and fluorinated insulators on the movement characteristics of the metal particles.

2. The method according to claim 1, characterized in that The insulator model in step 1 is a 500kV AC GIS pot-type insulator, and other model areas include coaxially arranged high-voltage conductors and grounded casing\insulating gas.

3. The method according to claim 1, characterized in that In step 1, the outer radius of the GIS coaxial conductor is set to 80-100 mm, and the inner diameter of the grounding shell is set to 250-300 mm.

4. The method according to claim 1, characterized in that: In step 1, the materials of the high-voltage conductor and the grounding shell are aluminum alloy, the insulator material is epoxy resin / aluminum oxide composite material, and the insulating gas is sulfur hexafluoride.

5. The method according to claim 4, characterized in that In step 1, the relative dielectric constants of the uniform insulator and the sulfur hexafluoride gas are set to 5-7 and 1-3 respectively.

6. The method according to claim 1, characterized in that In step 1, the high-voltage conductor of the model is connected to an AC voltage of 500 kV and 50 Hz, the metal casing is grounded, and the sulfur hexafluoride gas pressure inside the GIS is 0.5-0.7 MPa.

7. The method according to claim 1, characterized in that After the insulator is fluorinated and modified in step 2, the relative dielectric constant of its surface area decreases to 2-3, and the dielectric parameters of other model parts remain unchanged.

8. The method according to claim 1, characterized in that: In step three, the motion model of metal particles in the AC electric field takes into account the effects of electric field force, gravity, electric field gradient force and gas resistance on the metal particles.

9. The method according to claim 1, characterized in that: In step 4, releasing metal particles at different positions on the inner surface of the GIS casing refers to releasing metal particles at different distances from the surface of the insulator, and the release distances are 10, 20, and 30 mm respectively.

10. The method according to claim 1, characterized in that In step 4, releasing metal particles of different particle sizes on the inner surface of the GIS shell refers to spherical metal particles with different diameters, and the particle sizes of the metal particles are 0.1, 0.2, and 0.4 mm respectively.

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