Multi-section telescopic electrode and self-adaptive radial method for treating surface of sleeve core body

Abstract

The invention provides a multi-section telescopic electrode which comprises at least one pair of electrode parts, each pair of electrode parts comprises an upper arc plate and a lower arc plate, a low-voltage electrode is arranged at one end of the lower surface of the upper arc plate, a high-voltage electrode is arranged at the opposite position of the upper surface of the lower arc plate, and the high-voltage electrode is connected with a power source. A plasma discharge area occurs between the high-voltage electrode and the grounding electrode, and discharge gas enters the discharge area from the space between the upper arc plate and the lower arc plate. The invention further provides an adaptive radial method for treating the surface of the casing core. Surface treatment is carried out on the casing pipe core body through the multiple sections of telescopic electrodes, and the hydrophobicity and the surface pressure resistance of the casing pipe core body are synchronously improved. According to the invention, uniform and efficient surface modification is carried out on the sleeve core body in the sleeve core body gas composite insulating sleeve, the surface characteristics of the sleeve core body are improved, and moisture accumulation and charge distortion are inhibited, so that the long-term operation reliability of high-voltage power equipment is improved, and the hydrophobicity and along-surface voltage resistance characteristics of the surface of the sleeve core body are improved.

Description

Technical Field

[0001] This invention belongs to the field of plasma applications, and designs a multi-section telescopic electrode and an adaptive radial method for processing the surface of a sleeve core. Background Technology

[0002] SF6 gas-insulated bushings with a core are core equipment in ultra-high voltage direct current (UHVDC) transmission systems. These bushings typically use an epoxy resin-impregnated paper-type insulating core as the main insulation, with SF6 gas filling as auxiliary insulation. However, with the continuous increase in UHV transmission capacity and voltage levels, the electric field strength faced by the internal insulation structure of the bushing is increasing daily. As the solid insulation body, the gas-solid interface of the bushing core is prone to surface flashover due to insufficient intrinsic material properties, becoming a bottleneck restricting the long-term reliability of the bushing.

[0003] The main technical problems currently existing are as follows:

[0004] Interface defects caused by insufficient surface wettability: Epoxy resin itself is a low surface energy material with poor compatibility with SF6 gas, and it easily adsorbs gaseous impurities or moisture during long-term operation, leading to a decrease in surface hydrophobicity. When partial discharge exists inside the bushing, a conductive channel can easily form at the gas-solid interface, triggering surface flashover.

[0005] Surface charge accumulation and electric field distortion: The high resistivity of epoxy materials makes it difficult for surface charges to dissipate. Under DC high voltage, charge accumulation will cause local electric field distortion, which will significantly reduce the surface withstand voltage strength.

[0006] The core of the casing is a columnar structure with varying inner diameter. It is large in size and has a special shape, and the existing plasma device structure cannot meet its processing requirements. Summary of the Invention

[0007] 1. The technical problem to be solved:

[0008] By performing surface treatment on the casing core, its hydrophobicity and surface pressure resistance are simultaneously improved.

[0009] 2. Technical Solution:

[0010] To address the above problems, the present invention provides a multi-section telescopic electrode, comprising at least one pair of electrode portions. Each pair of electrode portions includes an upper arc plate and a lower arc plate. A low-voltage electrode is provided at one end of the lower surface of the upper arc plate, and a high-voltage electrode is provided at a relative position on the upper surface of the lower arc plate. The high-voltage electrode is connected to a power source. A plasma discharge region occurs between the high-voltage electrode and the ground electrode, and discharge gas enters the discharge region from between the upper and lower arc plates.

[0011] A continuous broken line is provided between the upper and lower arc plates. The upper end of the connecting broken line is connected to the lower surface of the upper arc plate, and the lower end of the connecting broken line is connected to the upper surface of the lower arc plate. The intersections of the continuous broken lines are connected by a tension spring.

[0012] It also includes support bars, each of which integrates a small pressure sensor. One end of each support bar is connected to the outer surface of the processed sleeve core, and the other end is connected to a continuous zigzag line. Each support bar is connected to an axial motion drive unit, which is equipped with an adjustment module and is connected to a control unit.

[0013] An epoxy resin pulley is installed at the bottom of the support bar, and the bottom of the pulley is in contact with the outer surface of the processed sleeve core.

[0014] The power supply is a high-voltage pulse power supply unit.

[0015] The power supply parameters are: voltage amplitude 14 kV, repetition frequency 5 kHz, pulse rise time 100 ns, pulse width 800 ns, and pulse fall time 100 ns.

[0016] The discharge gas is a mixture of argon, carbon tetrafluoride, and hydrogen. The argon, carbon tetrafluoride, and hydrogen in the gas cylinder are sequentially introduced into the mixing cylinder by the flow rate control platform and mixed evenly. Then, the gas path is divided into multiple gas inlets by the gas equalization valve and enters each discharge area.

[0017] Each of the vents has a honeycomb-shaped hemispherical air outlet at its bottom.

[0018] The working gas parameters for the discharge gas are: Ar gas flow rate of 8 L / min, CF4 and H2 flow rates of 80 mL / min and 40 mL / min, respectively.

[0019] The present invention also provides a method for processing the adaptive radial direction of the sleeve core surface, using the aforementioned flexible electrode, characterized by comprising the following steps:

[0020] Step S01: Connect the control unit, axial motion drive unit, high-voltage pulse power supply unit, air circuit unit, and electrode section;

[0021] Step S02: Fix the sleeve core to be processed, install the electrode part on the predetermined track and place it on one side of the sleeve core;

[0022] Step S03: Adjust the processing distance between the electrode part and the sleeve core to keep it within 3 mm;

[0023] Step S04: Connect the high-voltage electrode to the nanosecond pulse power supply;

[0024] Step S05: Connect the gas circuit unit to the gas equalization valve, and the gas is introduced into the discharge area through the gas inlet;

[0025] Step S06: Set the working gas parameters through the control unit: Ar gas flow rate is 8 L / min, CF4 and H2 flow rates are 80 mL / min and 40 mL / min, respectively;

[0026] Step S07: Set power supply parameters: voltage amplitude 14 kV, repetition frequency 5 kHz, pulse rise time 100 ns, pulse width 800 ns, pulse fall time 100 ns;

[0027] Step S08: The sleeve core is dynamically processed at a speed of 20 mm / min. The control unit automatically adjusts the axial motion drive unit and monitors the force on each support bar in real time with the help of pressure sensors. The position of the support bar 4 is adjusted by the adjustment module 5 to ensure that the pressure does not exceed 3 N.

[0028] Step S09: Repeat the process twice for a single sleeve core;

[0029] Step S10: Complete the surface modification of the sleeve core material.

[0030] 3. Beneficial effects:

[0031] This invention utilizes multi-section telescopic electrodes to perform surface treatment on the bushing core, simultaneously improving its hydrophobicity and surface pressure resistance. The bushing core of the SF6 gas composite insulating bushing undergoes uniform and efficient surface modification. By optimizing the microstructure of the epoxy surface, its surface properties are improved, enhancing the surface characteristics of the bushing core, inhibiting moisture accumulation and charge distortion, thereby improving the long-term operational reliability of high-voltage power equipment and achieving multi-faceted performance enhancements. Furthermore, plasma surface modification simultaneously improves the hydrophobicity and surface pressure resistance of the bushing core surface.

[0032] This invention has the advantages of simple process, environmental friendliness and high processing efficiency, and will not cause damage to the surface of epoxy matrix. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the overall structure of the device.

[0034] Figure 2 This is a schematic diagram of the gas path unit structure.

[0035] Figure 3 This is a schematic diagram of the electrode structure.

[0036] Figure 4 This is a schematic diagram of the electrode unit structure.

[0037] Figure 5 This is a schematic diagram of the telescopic unit combination structure.

[0038] Explanation of reference numerals in the attached diagram: 1. Electrode section; 2. Gas path section; 3. Telescopic section; 4. Support bar; 5. Adjustment module; 6. High-voltage electrode; 7. Grounding electrode; 8. Telescopic unit. Detailed Implementation

[0039] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0040] like Figure 1 , Figure 3 and Figure 4 As shown, the present invention provides a multi-section telescopic electrode, including at least one pair of electrode parts 1. Each pair of electrode parts 1 includes an upper arc plate and a lower arc plate. A low-voltage electrode 6 is provided at one end of the lower surface of the upper arc plate, and a high-voltage electrode 7 is provided at a relative position on the upper surface of the lower arc plate. The high-voltage electrode 7 is connected to a power source. A plasma discharge region occurs between the high-voltage electrode 6 and the ground electrode 7, and discharge gas enters the discharge region from between the upper and lower arc plates.

[0041] In one embodiment, the main body of a single electrode portion 1 is made of silicone, with specific structural dimensions of: inner diameter 200 mm, outer diameter 280 mm, thickness 15 mm, and initial arc angle 80°. Its internal high-voltage electrode 6 and grounding electrode 7 are made of 1 mm thick aluminum sheets. To reduce edge effects, the edges of both the high-voltage electrode 6 and the grounding electrode 7 are rounded with a spacing of 2 mm.

[0042] The discharge area will flow out of the electrode part 1 through the airflow of the discharge gas. Therefore, when processing the sleeve core, the sleeve core is placed on the side of the electrode part 1 where the high voltage electrode 7 and the low voltage electrode 6 are located.

[0043] The multi-section telescopic electrode used in this invention, through its unique radial adjustment capability, ensures the uniformity of plasma distribution during the processing.

[0044] In one embodiment, such as Figure 5 As shown, a continuous broken line 8 is provided between the upper arc plate and the lower arc plate. The upper end of the connecting broken line is connected to the lower surface of the upper arc plate, and the lower end of the connecting broken line is connected to the upper surface of the lower arc plate. The intersections of the continuous broken lines are connected by a tension spring.

[0045] The overall scaling is achieved by expanding / shrinking the continuous zigzag lines 8. This is the telescopic component 3. The intersections of the continuous zigzag lines are connected by tension springs. Each telescopic unit has a small tension spring structure inside, so that the entire multi-section telescopic electrode unit tends to the minimum inner diameter in its natural state.

[0046] In one embodiment, the device further includes support bars 4, each of which integrates a small pressure sensor. One end of each support bar 4 is connected to the outer surface of the processed sleeve core, and the other end is connected to the continuous zigzag line 8. Each support bar 4 is connected to an axial motion drive unit, and the axial motion drive unit is provided with an adjustment module 5, which is connected to a control unit.

[0047] The control unit includes a gas flow rate control platform, a power parameter control platform, and a dynamic processing control platform. The gas flow rate control platform is used to precisely adjust the process gas flow rate, while the power parameter control platform is used to set and monitor key electrical parameters such as pulse voltage and frequency to ensure the consistency of plasma processing. The electrode control platform is used to control the movement of the electrode device to achieve continuous processing of the sleeve core surface.

[0048] The function of support bar 4 is to maintain the processing distance between the bottom of each multi-section telescopic electrode and the material surface within the range of 0~3mm. To avoid scratches or damage to the core surface, epoxy resin pulleys are installed at the bottom of support bar 4. A small pressure sensor is integrated inside support bar 4 to monitor the interaction force between the support bar and the core surface. The control unit controls the adjustment module 5 on the axial motion drive unit, which mainly uses up-and-down fine adjustments to ensure that the pressure value of any sensor is less than 3 N.

[0049] The electrode control unit monitors and adjusts the forces between all the support bars 4 and the surface of the processed material to prevent the support bars 4 from damaging the insulation performance of the bushing core surface during dynamic processing.

[0050] The electrode unit integrates a support bar with a pressure sensor and an adjustment module, which can monitor and control the force between the electrode and the core surface in real time. This ensures that the processing distance remains constant within the optimal range of 0~3mm while effectively preventing mechanical parts from scratching or damaging the precision insulating surface, thus guaranteeing the safety of the processing process and the integrity of the core.

[0051] In one embodiment, the power supply is a high-voltage pulse power supply unit, specifically a nanosecond pulse power supply. Compared to high-frequency AC power supplies or microsecond pulse power supplies, nanosecond pulse power supplies offer advantages such as high energy efficiency and strong excited plasma activity, effectively suppressing electrode temperature rise and ensuring the stability of the processing and the safety of the materials.

[0052] In one embodiment, the power supply parameters are as follows: voltage amplitude 14 kV, repetition frequency 5 kHz, pulse rise time 100 ns, pulse width 800 ns, and pulse fall time 100 ns. The optimized power supply parameters enable the plasma to have a suitable energy density, effectively achieving surface modification while avoiding damage to the epoxy matrix.

[0053] In one embodiment, the discharge gas is a mixture of argon, carbon tetrafluoride, and hydrogen. The multi-gas synergistic plasma surface fluorination modification process uses an Ar / CF4 / H2 mixed gas as the discharge atmosphere. Through nanosecond pulsed plasma technology, nano-etching and chemical fluorination grafting are simultaneously achieved on the epoxy surface, significantly improving the material's hydrophobicity and charge dissipation ability, thereby enhancing the performance and service life of the sleeve core.

[0054] like Figure 2 As shown, argon (Ar), carbon tetrafluoride (CF4), and hydrogen (H2) in the gas cylinder are sequentially introduced into the mixing cylinder through a flow rate control platform for uniform mixing. The mixture is then evenly divided into multiple gas inlets by a gas equalization valve, thus creating the required discharge atmosphere. Multiple gas path sections 2 are connected to the gas equalization valve. After being distributed by the equalization valve, the gas enters each gas path section 2, thereby forming a uniform discharge gas atmosphere on both sides of the symmetrical front and back of the multi-section telescopic electrode unit. A honeycomb-shaped hemispherical gas outlet is provided at the bottom of each gas path section 2, which helps to achieve uniform gas distribution and promotes discharge uniformity.

[0055] The present invention also provides a method for processing the adaptive radial direction of the sleeve core surface, using the aforementioned flexible system, characterized by comprising the following steps:

[0056] Step S01: Connect the control unit, axial motion drive unit, high-voltage pulse power supply unit, air circuit unit, and electrode section;

[0057] Step S02: Fix the sleeve core to be processed, install the electrode part on the predetermined track and place it on one side of the sleeve core;

[0058] Step S03: Adjust the processing distance between the electrode part and the sleeve core to keep it within 3 mm;

[0059] Step S04: Connect the high-voltage electrode to the nanosecond pulse power supply;

[0060] Step S05: Connect the gas circuit unit to the gas equalization valve, and the gas is introduced into the discharge area through the gas inlet;

[0061] Step S06: Set the working gas parameters through the control unit: Ar gas flow rate is 8 L / min, CF4 and H2 flow rates are 80 mL / min and 40 mL / min, respectively;

[0062] Step S07: Set power supply parameters: voltage amplitude 14 kV, repetition frequency 5 kHz, pulse rise time 100 ns, pulse width 800 ns, pulse fall time 100 ns;

[0063] Step S08: The sleeve core is dynamically processed at a speed of 20 mm / min. The control unit automatically adjusts the axial motion drive unit and monitors the force on each support bar in real time with the help of pressure sensors. The position of the support bar 4 is adjusted by the adjustment module 5 to ensure that the pressure does not exceed 3 N.

[0064] Step S09: Repeat the process twice for a single sleeve core;

[0065] Step S10: Complete the surface modification of the sleeve core material.

[0066] The high-voltage pulse power supply unit creates a stable, strong electric field between the high-voltage electrode 7 and the ground electrode 6 of the multi-section telescopic electrode unit, ionizing the Ar / CF4 / H2 mixed gas to generate highly active plasma. On one hand, the high-energy particles in the plasma achieve a nanoscale etching effect on the epoxy resin surface, increasing surface roughness and thus optimizing its microstructure. On the other hand, in the plasma environment, the fluorine-containing active groups generated by the decomposition of CF4 gas, under the synergistic effect of H2, can efficiently undergo a grafting reaction with epoxy surface molecules, forming a stable fluorinated carbon modified layer. This modified layer significantly reduces the surface energy of the material, endowing the sleeve core with excellent hydrophobicity. Simultaneously, the formation of the fluorinated layer alters the surface charge distribution and migration characteristics; the shallow traps introduced on the material surface promote the dissipation of accumulated charges and effectively suppress electric field distortion.

[0067] The multi-segment telescopic electrode design employed in this invention, through its unique radial adjustment capability, ensures the uniformity of plasma distribution during processing. Optimized power supply parameters enable the plasma to achieve a suitable energy density, effectively achieving surface modification while avoiding damage to the epoxy matrix.

[0068] Table 1 shows the performance test results of epoxy before and after dynamic treatment in one embodiment.

[0069] Table 1 shows the performance test results of epoxy before and after dynamic treatment.

[0070] Table 1. Properties before and after epoxy treatment

[0071] Epoxy resin Before modification After modification WCA(°) 64 94 Surface withstand voltage (kV) 8.2 9.3 .

[0072] This invention provides a radially adjustable multi-section telescopic electrode device based on low-temperature plasma treatment technology. This device is used to modify the surface of the SF6 gas composite insulating bushing core. Through surface modification, the microstructure of the insulating paper is optimized, thereby improving its hydrophobicity and surface pressure resistance.

Claims

1. A multi-section telescopic electrode, characterized in that: It includes at least one pair of electrode parts (1), each pair of electrode parts (1) includes an upper arc plate and a lower arc plate. A low-voltage electrode (6) is provided at one end of the lower surface of the upper arc plate, and a high-voltage electrode (7) is provided at a relative position on the upper surface of the lower arc plate. The high-voltage electrode (7) is connected to a power source. The plasma discharge region occurs between the high-voltage electrode (6) and the ground electrode (7). The discharge gas enters the discharge region from between the upper arc plate and the lower arc plate.

2. The multi-section telescopic electrode as described in claim 1, characterized in that: A continuous broken line (8) is provided between the upper arc plate and the lower arc plate. The upper end of the connecting broken line is connected to the lower surface of the upper arc plate, and the lower end of the connecting broken line is connected to the upper surface of the lower arc plate. The intersections of the continuous broken lines are connected by a tension spring.

3. The multi-section telescopic electrode as described in claim 2, characterized in that: It also includes support bars (4), each of which integrates a small pressure sensor. One end of each support bar (4) is connected to the outer surface of the processed sleeve core, and the other end is connected to the continuous zigzag line (8). Each support bar (4) is connected to an axial motion drive unit, and the axial motion drive unit is provided with an adjustment module (5). The adjustment module (5) is connected to a control unit.

4. The multi-section telescopic electrode as described in claim 3, characterized in that: The bottom of the support bar (4) is equipped with an epoxy resin pulley, and the bottom of the pulley is in contact with the outer surface of the processed sleeve core.

5. The multi-section telescopic electrode as described in any one of claims 1-4, characterized in that: The power supply is a high-voltage pulse power supply unit.

6. The multi-section telescopic electrode as described in claim 5, characterized in that: The power supply parameters are: voltage amplitude 14 kV, repetition frequency 5 kHz, pulse rise time 100 ns, pulse width 800 ns, and pulse fall time 100 ns.

7. The multi-section telescopic electrode as described in any one of claims 1-5, characterized in that: The discharge gas is a mixture of argon, carbon tetrafluoride, and hydrogen. The argon, carbon tetrafluoride, and hydrogen in the gas cylinder are sequentially introduced into the mixing cylinder by the flow rate control platform and mixed evenly. Then, the gas path is divided into multiple gas inlets by the gas equalization valve and enters each discharge area.

8. The multi-section telescopic electrode as described in claim 7, characterized in that: Each of the vents has a honeycomb-shaped hemispherical air outlet at its bottom.

9. The multi-section telescopic electrode as described in claim 7, characterized in that: The working gas parameters for the discharge gas are: Ar gas flow rate of 8 L / min, CF4 and H2 flow rates of 80 mL / min and 40 mL / min, respectively.

10. A method for processing the adaptive radial direction of a sleeve core surface, using a multi-section telescopic electrode as described in any one of claims 1-9, characterized in that: Includes the following steps: Step S01: Connect the control unit, axial motion drive unit, high-voltage pulse power supply unit, air circuit unit, and electrode section; Step S02: Fix the sleeve core to be processed, install the electrode part on the predetermined track and place it on one side of the sleeve core; Step S03: Adjust the processing distance between the electrode part and the sleeve core to keep it within 3 mm; Step S04: Connect the high-voltage electrode to the nanosecond pulse power supply; Step S05: Connect the gas circuit unit to the gas equalization valve, and the gas is introduced into the discharge area through the gas inlet; Step S06: Set the working gas parameters through the control unit: Ar gas flow rate is 8 L / min, CF4 and H2 flow rates are 80 mL / min and 40 mL / min, respectively; Step S07: Set power supply parameters: voltage amplitude 14 kV, repetition frequency 5 kHz, pulse rise time 100 ns, pulse width 800 ns, pulse fall time 100 ns; Step S08: The sleeve core is dynamically processed at a speed of 20 mm / min. The control unit automatically adjusts the axial motion drive unit and monitors the force on each support bar in real time with the help of the pressure sensor. The position of the support bar (4) is adjusted by the adjustment module (5) to ensure that the pressure does not exceed 3 N. Step S09: Repeat the process twice for a single sleeve core; Step S10: Complete the surface modification of the sleeve core material.

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