Pressurized leakage stopping method suitable for gas leakage of high-voltage switch flange gap

Abstract

The invention relates to an under-pressure leaking stoppage method for gas leakage of a high-voltage switch flange gap. The under-pressure leaking stoppage method comprises the steps that the surface of a high-voltage switch leakage flange is polished and cleaned; the two sides of the leakage flange are each provided with at least one sealing piece, and the sealing pieces surround the outer circumferential face of the air chamber cylinder by one circle and are attached to the outer circumferential face in a gapless mode. An elastic sealing layer is wound on the peripheries of the leakage flange and the sealing piece; fastening pieces are installed, the elastic sealing layer and the sealing pieces are tightly fixed to the peripheral face of the air chamber cylinder of the switchgear, and the fastening pieces provide radial pressing force for the air chamber cylinder; and winding and curing the high-strength pressure-resistant layer. Through the composite design of sealing, elastic buffering, high-strength pressure resisting and pressing, reliable sealing under the high-pressure working condition is achieved.

Description

Technical Field

[0001] This invention relates to the field of sealing and plugging technology for high-voltage electrical equipment, specifically to a pressurized sealing method for gas leakage in the gap of high-voltage switch flanges. Background Technology

[0002] Sulfur hexafluoride (SF6) gas possesses excellent insulation and arc-extinguishing properties, and is widely used in 10-500kV high-voltage switchgear. The flange connections of high-voltage switches are high-risk areas for SF6 gas leakage: after long-term operation, the flange sealing surface is prone to deterioration in sealing performance due to vibration, corrosion, and aging; or, during installation, loose sealing surfaces or uneven bolt preload can also cause SF6 gas leakage.

[0003] SF6 gas is a potent greenhouse gas; leaks not only pollute the environment but also reduce the insulation and arc-extinguishing performance of high-voltage switches, potentially causing equipment failures and affecting the safe and stable operation of the power system. Existing leak-sealing technologies have many shortcomings: (1) The traditional method requires disassembling the switch flange to replace the gasket, which is complicated, time-consuming, and requires power outage, affecting the reliability of power supply; (2) Emergency sealing often uses a single sealing ring or wrapping tape, which lacks sufficient clamping force and structural strength. It is prone to failure under high pressure (usually 0.6-0.8MPa) conditions and has poor sealing durability. (3) Some leak sealing solutions use welding to seal the flange body, which is easy to damage the flange body and poses a fire risk. They are not suitable for live-line work scenarios. (4) Existing clamp-type sealing methods mostly involve single-point or small-scale clamping, resulting in uneven pressure distribution and difficulty in achieving full fit of the sealing surfaces on both sides of the flange, thus the risk of leakage remains high.

[0004] Therefore, there is an urgent need for an SF6 gas sealing technology that requires no equipment disassembly, provides reliable and long-lasting sealing, withstands high pressure, and is suitable for live-line work, in order to solve the problem of leakage in the flange gap of high-voltage switches. Summary of the Invention

[0005] To address the technical problems of existing methods for sealing SF6 gas leaks in high-voltage switch flanges, such as "complex disassembly, poor sealing durability, poor high-pressure resistance, and cumbersome operation," this invention provides a pressurized sealing method suitable for gas leaks in the gaps of high-voltage switch flanges.

[0006] A live leak sealing method for gas leakage in high-voltage switch flange gaps includes the following steps: S1: Grind and clean the surface of the high-voltage switch leakage flange; S2: At least one sealing element is installed on each side of the leakage flange. The sealing element is wrapped around the outer peripheral surface of the gas chamber cylinder and fits the outer peripheral surface without gap. The central axis of each sealing element coincides with the axis of the gas chamber cylinder. S3: Wrap an elastic sealing layer around the leaking flange and the seal; S4: Install fasteners to tightly fix the elastic sealing layer and sealing components to the outer peripheral surface of the switchgear air chamber cylinder. The fasteners provide radial clamping force to the cylinder. S5: Wrap a high-strength pressure-resistant layer and cure; A high-strength pressure-resistant layer material is wrapped around the elastic sealing layer and fasteners. The elastic sealing layer and fasteners are bonded to the high-strength pressure-resistant layer with adhesive. The layers of high-strength pressure-resistant layer material are bonded and fixed with adhesive. After wrapping, the adhesive layer is left to cure initially.

[0007] Furthermore, it also includes the following steps: S6: Sealing test; Perform leakage detection on the periphery of the leaking flange to test whether the leakage rate meets the engineering requirements. If not, proceed to the next step. S7: Remove the sealing layer, pressure-resistant layer and fasteners, and repeat steps S1-S6 until the leakage rate meets the engineering requirements.

[0008] Furthermore, in S1, the surface roughness Ra of the leaking flange after grinding is ≤3.2μm.

[0009] Furthermore, the seal described in S2 is made of fluororubber or perfluoroelastomer material, which has the characteristics of being resistant to SF6 gas corrosion and has a Shore hardness of 75-85HA.

[0010] Furthermore, the elastic sealing layer is made of latex bandage material.

[0011] Furthermore, the high-strength pressure-resistant layer material is made of carbon fiber cloth or steel wire mesh.

[0012] Furthermore, the fasteners are installed on the periphery of the elastic sealing layer and inside the high-strength pressure-resistant layer. At least one fastener is provided on each side of the leakage flange, and the first fastener presses against the periphery of the first seal and secures it.

[0013] Furthermore, the fastener is a clamp, which includes a high-strength arc-shaped clamp body, connecting bolts and pressure adjusting nuts, and an arc-shaped pad adapted to the high-strength pressure-resistant layer is provided on the inner side of the clamp body.

[0014] Furthermore, when tightening the fasteners in S4, a torque wrench is used to control the torque, with a torque value of 80 to 120 N·m, to ensure sufficient tightening force.

[0015] Furthermore, the outermost end of the elastic sealing layer or fastener is fixed to the gas chamber cylinder by adhesive.

[0016] This invention achieves reliable sealing under high-pressure conditions through a composite design of "sealing + elastic buffering + high-strength pressure resistance + compression".

[0017] When two sealing rings are installed on each side of the flange, a "double-sided double-channel" sealing barrier is formed, which expands the sealing contact area and improves the sealing redundancy.

[0018] The elastic sealing layer utilizes the elastic deformation capability of the elastic sealing material to fill the tiny gaps between the flange and the sealing ring, and between the sealing ring and the reinforcing layer. At the same time, it plays a buffering role, offsetting the impact of vibration of high-voltage switchgear on the seal.

[0019] A high-strength pressure-resistant layer, after being wound, forms a rigid pressure-resistant layer that constrains the internal sealing structure, preventing the elastic sealing layer from deforming and failing under high pressure; it also ensures uniform pressure within the pressure-resistant layer, preventing leakage caused by insufficient local pressure. When carbon fiber cloth is used as the high-strength pressure-resistant material, it also possesses high strength, high pressure resistance, and corrosion resistance, making it suitable for harsh environments.

[0020] The radial fixing parts of the gas chamber cylinder of the high-voltage switchgear are tightened to ensure that the sealing rings on both sides of the leakage flange are tightly fitted to the outer circumferential surface of the gas chamber cylinder, so as to prevent the gas leaking from the flange from overflowing to both sides. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the leak-sealing method of the present invention; Figure 2 This is one of the embodiments of the present invention.

[0022] Figure 2 In the middle, 1. Fasteners, 2. Seals, 3. High-strength pressure-resistant layer, 4. Elastic sealing layer, 5. Flanges, 6. Gas chamber shell of GIS switchgear. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer and more understandable, the technical solutions of the embodiments of this invention will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0024] A live leak sealing method for gas leakage in high-voltage switch flange gaps includes the following steps: S1: Grind and clean the surface of the high-voltage switch leakage flange 5; S2: At least one sealing element is installed on each side of the leakage flange 5. The sealing element surrounds the outer circumference of the gas chamber cylinder 6 and fits the outer circumference without gap. The central axis of each sealing element coincides with the axis of the gas chamber cylinder 6. S3: Wrap an elastic sealing layer 4 around the outer periphery of the leaking flange 5 and the seal; S4: Install fastener 1 to tightly fix the elastic sealing layer 4 and the sealing element on the outer peripheral surface of the switchgear air chamber 6. Fastener 1 provides radial clamping force to the air chamber 6. S5: Wrap high-strength pressure-resistant layer 3 and cure; High-strength pressure-resistant layer 3 material is wrapped around the elastic sealing layer 4 and fastener 1. The elastic sealing layer 4 and fastener 1 are bonded to the high-strength pressure-resistant layer 3 with adhesive. The high-strength pressure-resistant layer 3 material is bonded and fixed between layers with adhesive. After wrapping, the adhesive layer is left to cure initially. S6: Sealing test; Perform a leak detection test on the periphery of the leaking flange 5 to test whether the leakage rate meets the engineering requirements. If not, proceed to the next step. S7: Remove the sealing layer, pressure-resistant layer and fastener 1, and repeat steps S1-S6 until the leakage rate meets the engineering requirements.

[0025] S4, the outermost end of the elastic sealing layer 4 or the sealing element is fixed to the gas chamber cylinder 6 by adhesive.

[0026] In one embodiment, S1, specifically, involves grinding the two end faces and outer peripheral surface of the leaking flange 5 smooth, removing oil, rust, and aged seal residue, cleaning it thoroughly, and letting it dry.

[0027] The cleaning process can be achieved using specialized cleaning agents, such as a metal paint remover and a metal rust remover.

[0028] In S1, the surface roughness Ra of the leak flange 5 after grinding is ≤3.2μm to ensure the sealing performance between the seal and the outer circumference of the gas chamber cylinder 6.

[0029] The surface of the leaking flange 5 includes the outer peripheral surface and the two end faces of the flange 5 where the leak occurs.

[0030] In one embodiment, all the sealing elements are fitted tightly to the outer periphery of the gas chamber 6 of the switchgear without gaps, and the central axis of the sealing element coincides with the axis of the gas chamber 6. The sealing element is a sealing ring, or a sealing strip may be used. The sealing element is made of fluororubber or perfluoroelastomer, which has the characteristics of being resistant to SF6 gas corrosion and has a Shore hardness of 75-85HA.

[0031] In one embodiment, such as Figure 1 At least one sealing ring is affixed to each side of the leakage flange 5, with each sealing ring fitting snugly against the outer circumference of the switchgear gas chamber 6 without gaps. A first sealing ring, a second sealing ring, and so on are arranged on both sides of the leakage flange 5, with a preset width interval between the second sealing ring and the first sealing ring. Figure 1In this context, the sealing ring is an "O" ring.

[0032] In one embodiment, the elastic sealing layer 4 in S3 seals and wraps the leaking flange 5 and the sealing element with an elastic strip material. The elastic strip material is kept taut during the winding process, and the overlap width of adjacent elastic strip materials is not less than 1 / 2 of the bandwidth.

[0033] In one embodiment, the elastic sealing layer 4 is made of latex bandage.

[0034] In one embodiment, the reinforcing pressure-resistant layer material described in S5 is carbon fiber cloth or steel wire mesh. It is acceptable as long as it possesses high strength and pressure resistance; no specific limitations are imposed.

[0035] In one embodiment, the adhesive in S5 is an epoxy resin, a neoprene rubber adhesive, or a cyanoacrylate adhesive.

[0036] In one embodiment, such as Figure 1 The fastener 1 described in S4 is installed on the periphery of the elastic sealing layer 4. At least one fastener is installed on each side of the leakage flange 5. The first fastener presses against the periphery of the first seal and tightens it. The fastener provides radial clamping force.

[0037] In one embodiment, a second fastener is also provided, which is disposed around the spacer elastic sealing layer 4 between the first sealing ring and the second sealing ring; In one embodiment, a third fastener is also provided, installed on the periphery of the elastic sealing layer 4 outside the second sealing ring; similarly, the third fastener is used to provide radial clamping force.

[0038] In one embodiment, such as Figure 1 The outermost end of the elastic sealing layer 4 or the fastener is fixed to the air chamber cylinder 6 by adhesive.

[0039] In one embodiment, the fastener is a clamp, which includes an arc-shaped clamp body, a connecting bolt and a pressure adjusting nut, and an arc-shaped pad adapted to the high-strength pressure-resistant layer 3 is provided on the inner side of the clamp body.

[0040] In one embodiment, the arc-shaped clamp body of the clamp is made of high-strength alloy steel.

[0041] In one embodiment, the pad is made of silicone rubber with an anti-slip texture on the surface, and the pad has a thickness of 3-5 mm.

[0042] The fastening clamps are tightened by adjusting the clamp tension using connecting bolts. Preferably, the tightening pressure of each clamp is in the range of 2–3 MPa.

[0043] When tightening the fasteners in S4, a torque wrench is used to control the torque, with a torque value of 80 to 120 N·m, to ensure sufficient tightening force.

[0044] In one embodiment, the fastener may also be a binding rope.

[0045] In one embodiment, in S6, the leak detection is performed using pressure testing or a leak detector.

[0046] The above embodiments can be applied individually or in combination, provided that they are feasible.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A live leak sealing method for gas leakage in high-voltage switch flange gaps, characterized in that, It includes the following steps: S1: Grind and clean the surface of the high-voltage switch leakage flange; S2: At least one sealing element is installed on each side of the leakage flange. The sealing element is wrapped around the outer peripheral surface of the gas chamber cylinder and fits the outer peripheral surface without gap. The central axis of each sealing element coincides with the axis of the gas chamber cylinder. S3: Wrap an elastic sealing layer around the leaking flange and the seal; S4: Install fasteners to tightly fix the elastic sealing layer and sealing components to the outer peripheral surface of the switchgear air chamber cylinder. The fasteners provide radial clamping force to the cylinder. S5: Wrap a high-strength pressure-resistant layer and cure; A high-strength pressure-resistant layer material is wrapped around the elastic sealing layer and fasteners. The elastic sealing layer and fasteners are bonded to the high-strength pressure-resistant layer with adhesive. The layers of high-strength pressure-resistant layer material are bonded and fixed with adhesive. After wrapping, the adhesive layer is left to cure initially.

2. A live leak sealing method for gas leakage in high-voltage switch flange gaps, characterized in that, It also includes the following steps: S6: Sealing test; Perform leakage detection on the periphery of the leaking flange to test whether the leakage rate meets the engineering requirements. If not, proceed to the next step. S7: Remove the sealing layer, pressure-resistant layer and fasteners, and repeat steps S1-S6 until the leakage rate meets the engineering requirements.

3. A live leak sealing method for gas leakage in high-voltage switch flange gaps according to claim 1, characterized in that, In S1, the surface roughness Ra of the leaking flange after grinding is ≤3.2μm.

4. A live leak sealing method for gas leakage in high-voltage switch flange gaps according to claim 1, characterized in that, The seal described in S2 is made of fluororubber or perfluoroelastomer material, which has the characteristics of being resistant to SF6 gas corrosion and has a Shore hardness of 75-85HA.

5. A live leak sealing method for gas leakage in high-voltage switch flange gaps according to claim 1, characterized in that, The elastic sealing layer is made of latex bandage material.

6. A live leak sealing method for gas leakage in high-voltage switch flange gaps according to claim 1, characterized in that, The high-strength pressure-resistant layer material is made of carbon fiber cloth or steel wire mesh.

7. A live leak sealing method for gas leakage in high-voltage switch flange gaps according to claim 1, characterized in that, The fasteners are installed on the periphery of the elastic sealing layer and inside the high-strength pressure-resistant layer. At least one fastener is installed on each side of the leakage flange. The first fastener presses against the periphery of the first seal and secures it.

8. A live leak sealing method for gas leakage in high-voltage switch flange gaps according to claim 1 or 7, characterized in that, The fastener is a clamp, which includes a high-strength arc-shaped clamp body, connecting bolts and pressure adjusting nuts, and an arc-shaped pad adapted to the high-strength pressure-resistant layer is provided on the inner side of the clamp body.

9. A live leak sealing method for gas leakage in high-voltage switch flange gaps according to claim 8, characterized in that, When tightening fasteners in the S4, a torque wrench is used to control the torque to ensure sufficient tightening force.

10. A live leak sealing method for gas leakage in high-voltage switch flange gaps according to claim 1 or 7, characterized in that, include: The outermost end of the elastic sealing layer or fastener is fixed to the gas chamber cylinder by adhesive.

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