High-voltage single-core cable outer sheath penetrability damage repairing method

Abstract

The invention relates to a penetrating damage repairing method for an outer sheath of a high-voltage single-core cable. The method comprises the following steps of: cleaning and wiping the outer sheath of the cable in sequence; stripping and processing the outer sheath of the damaged part; the insulating property of the outer sheath is recovered by using epoxy mud and an insulating tape; a waterproof tape is wrapped to recover the waterproof performance; a semi-conductive belt is lapped to recover the conductivity of the outermost layer; and carrying out insulation performance test to check the repair effect, and completing the penetrability damage repair of the outer sheath of the high-voltage single-core cable. According to the method, the insulation performance of the cable outer sheath can be rapidly and well recovered, and the method has potential engineering application value.

Description

Technical Field

[0001] The invention belongs to the technical field of cable operation, maintenance and repair, and in particular to a method for repairing penetrating damage to an outer sheath of a high-voltage single-core cable. Background Art

[0002] The outer sheath of the power cable is the outermost structural layer of the power cable, which is used to protect the inner structure of the power cable. For three-core cables, the main function of the outer sheath is mechanical protection and corrosion protection. For single-core high-voltage cables of 66kV and above, the outer sheath of the cable not only plays a role in mechanical protection and corrosion protection, but also plays the role of an insulating layer of the metal sheath. Therefore, the insulation performance of the outer sheath is very important. In addition to polyvinyl chloride outer sheath and polyethylene outer sheath, the types of outer sheaths of high-voltage cables also include metal-plastic composite jackets. In addition, the surface of the outer sheath of high-voltage single-core cables has a semi-conductive layer extruded or coated, which is significantly different from three-core power cables of 35kV and below. Whether it is a three-core cable or a single-core cable, maintaining the integrity of the outer sheath is a basic condition to ensure the long-term safe and reliable operation of the cable.

[0003] During construction and operation, the cable outer sheath may be damaged due to mechanical force, ants or small animals biting, etc., and severe damage may lead to penetrating damage. Penetrating damage is an open damage, which means that after the cable is pierced by external sharp objects, there will be obvious channels on the surface of the cable outer sheath, metal sheath and other structural layers; or the cable body and outer sheath are punctured due to insulation degradation. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and to propose a method for repairing penetrating damage to the outer sheath of a high-voltage single-core cable, which can better restore the insulation performance of the outer sheath of the cable and has potential engineering application value.

[0005] The present invention solves the technical problem by adopting the following technical solutions:

[0006] A method for repairing penetration damage of a high-voltage single-core cable outer sheath comprises the following steps:

[0007] Step 1: Clean and wipe the outer sheath of the cable;

[0008] Step 2, stripping and treating the outer sheath of the damaged part;

[0009] Step 3: Use epoxy mud and insulating tape to restore the insulation performance of the outer sheath;

[0010] Step 4: Wrap the waterproof tape to restore the waterproof performance;

[0011] Step 5, wrapping the semi-conductive tape to restore the outermost layer's conductive properties;

[0012] Step 6: Conduct insulation performance test to check the repair effect.

[0013] Moreover, the specific implementation method of step 1 is: use a glass sheet to scrape off the conductive layer within 50 mm around the damaged area and use a cleaning towel to remove surface impurities and dust particles. The scraped surface cannot be stained with semi-conductive material, and use a multimeter to test the conductivity of the scraped surface. The test result should show an open circuit.

[0014] Moreover, the specific implementation method of step 2 is: for the damage to the penetration of the cable outer sheath, different treatment measures are taken according to the size of the damage area, wherein the size of the damage area includes local pit damage and large-area damage.

[0015] Furthermore, the treatment measure for the local pit damage is: the sheath portion at the damaged portion is cut off, and the cut-off area is a circular area covering the damaged portion.

[0016] Furthermore, the treatment measure for the large-area damage is to remove the sheath at the damaged part as a whole, and the removed area is the entire sheath including the damaged area.

[0017] Moreover, the specific implementation method of step 3 is: for the damage to the penetration of the cable outer sheath, corresponding repair measures are taken according to the size of the damage area, wherein the size of the damage area includes local pit damage and large area damage;

[0018] The repair measures for local pothole damage are: fill the hole with epoxy mud or the same material as the cable sheath by heating to restore the insulation and sealing performance of the local pothole. The size of the repair should be consistent with the size of the cable outer sheath, and wrap the insulation tape with a range of 60mm in a semi-overlapping manner;

[0019] The repair measures for large-area damage are: use insulating tape to perform insulation sealing repair, and the size of the repair should be consistent with the size of the cable outer sheath.

[0020] Moreover, the specific implementation method of step 4 is: wrapping the waterproof tape requires covering the insulating tape range of more than 60 mm to ensure waterproof performance, and then wrapping the black PVC adhesive tape to enhance wear resistance and corrosion resistance.

[0021] Moreover, the specific implementation method of step 5 is: wrapping the semi-conductive tape to restore the semi-conductive performance, and the semi-conductive tape overlaps the outer conductive layer of the intact part of the cable on both sides by no less than 50mm to ensure the connectivity of the conductive layer.

[0022] Moreover, the specific implementation method of step 6 is: the insulation performance of the repaired outer sheath should meet the requirement of withstanding a 10kV DC voltage for 1 minute without breakdown.

[0023] The advantages and positive effects of the present invention are:

[0024] The present invention completes the repair of the penetration damage of the outer sheath of the high-voltage single-core cable by successively cleaning and wiping the outer sheath of the cable; stripping and treating the outer sheath of the damaged part; using epoxy mud and insulating tape to restore the insulation performance of the outer sheath; wrapping with waterproof tape to restore the waterproof performance; wrapping with semi-conductive tape to restore the outermost conductive performance; and performing insulation performance testing to check the repair effect. The present invention can quickly and well restore the insulation performance of the outer sheath of the cable, and has potential engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a flow chart of the present invention;

[0026] Figure 2 This is a schematic diagram of the outer sheath penetrating damage;

[0027] Figure 3 This is a schematic diagram of local pothole damage treatment;

[0028] Figure 4 This is a schematic diagram of large area damage treatment according to the present invention. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below with reference to the accompanying drawings.

[0030] A method for repairing penetrating damage to the outer sheath of a high-voltage single-core cable, such as Figure 1 As shown, the following steps are included:

[0031] Step 1: Clean and wipe the outer sheath of the cable.

[0032] Use a glass sheet to scrape off the conductive layer within 50mm around the damaged area and use a cleaning towel to remove surface impurities, dust particles, etc. Be careful not to leave any semi-conductive material on the scraped surface. Use a multimeter to check the scraped surface to confirm that there is no semi-conductive material left.

[0033] Step 2: Remove and treat the outer sheath of the damaged area.

[0034] For the penetration damage of the cable outer sheath, different treatment measures need to be taken according to the size of the damage area:

[0035] like Figure 2 As shown, the treatment measures for local pothole damage are: the sheath portion of the damaged portion (the maximum size does not exceed 1 / 2 of the cable diameter) is cut off, and the cut area is a circular area covering the damaged portion.

[0036] like Figure 3 As shown, the treatment measures for large-area damage are: the sheath at the damaged part (the maximum size exceeds 1 / 2 of the cable diameter) is completely removed, and the removed area is the entire sheath section including the damaged area.

[0037] Step 3: Use epoxy mud and insulating tape to restore the insulation performance of the outer sheath.

[0038] Use a utility knife to scrape away the damaged area of ​​the outer sheath. If the metal sheath is damaged, check whether the cable insulation shielding layer is damaged. For penetrating damage to the outer sheath of the cable, different repair measures need to be taken according to the size of the damaged area:

[0039] The repair measures for local pothole damage are: fill the pothole with epoxy mud or the same material of the cable sheath by heating (using polytetrafluoroethylene tape for shaping while heating) to restore the insulation and sealing properties of the local pothole. The size of the repair should be consistent with the size of the cable outer sheath, and wrap it with 60mm insulation tape in a semi-overlapping manner.

[0040] like Figure 4 As shown, the repair measures for large-area damage are: use insulating tape to perform insulation sealing repair, and the size of the repair is consistent with the size of the cable outer sheath.

[0041] Furthermore, in the above step 4, the waterproof tape is required to cover the insulating tape by more than 60 mm to ensure waterproof performance, and then the black PVC adhesive tape is wrapped to enhance the wear and corrosion resistance.

[0042] Step 4: Wrap the waterproof tape to restore the waterproof performance.

[0043] The waterproof tape should cover the insulating tape for more than 60mm to ensure waterproof performance. Then wrap it with black PVC adhesive tape to enhance wear and corrosion resistance.

[0044] Step 5: Wrap the semi-conductive tape to restore the outermost conductive property.

[0045] Wrap the semi-conductive tape to restore the semi-conductive performance. Wrap the outermost layer with two layers of PVC protective tape to protect the semi-conductive tape.

[0046] Step 6: Conduct insulation performance test to check the repair effect.

[0047] The insulation performance of the repaired outer sheath should be able to withstand a 10kV DC voltage for 1 minute without breakdown.

[0048] It should be emphasized that the embodiments described in the present invention are illustrative rather than restrictive. Therefore, the present invention includes but is not limited to the embodiments described in the specific implementation manner. Any other implementation manners derived by those skilled in the art based on the technical solution of the present invention also fall within the scope of protection of the present invention.

Claims

1. A method for repairing penetration damage to the outer sheath of a high-voltage single-core cable, characterized in that: The following steps are involved: Step 1: Clean and wipe the outer sheath of the cable; Step 2, stripping and treating the outer sheath of the damaged part; Step 3: Use epoxy mud and insulating tape to restore the insulation performance of the outer sheath; Step 4: Wrap the waterproof tape to restore the waterproof performance; Step 5, wrapping the semi-conductive tape to restore the outermost layer's conductive properties; Step 6: Conduct insulation performance test to check the repair effect.

2. A method for repairing penetrating damage to the outer sheath of a high-voltage single-core cable according to claim 1, characterized in that: The specific implementation method of step 1 is: use a glass sheet to scrape off the conductive layer within 50 mm around the damaged area and use a cleaning towel to remove surface impurities and dust particles. The scraped surface cannot be stained with semi-conductive materials, and use a multimeter to test the conductivity of the scraped surface. The test result should show an open circuit.

3. A method for repairing penetration damage to the outer sheath of a high-voltage single-core cable according to claim 1, characterized in that: The specific implementation method of step 2 is: for the damage to the penetration of the cable outer sheath, different treatment measures are taken according to the size of the damage area, where the size of the damage area includes local pothole damage and large-area damage.

4. A method for repairing penetration damage to the outer sheath of a high-voltage single-core cable according to claim 3, characterized in that: The treatment measure for the local pit damage is: the sheath portion at the damaged portion is cut off, and the cut-off area is a circular area covering the damaged portion.

5. A method for repairing penetration damage to the outer sheath of a high-voltage single-core cable according to claim 3, characterized in that: The treatment measure for the large area damage is: the sheath at the damaged part is completely removed, and the removed area is the entire sheath including the damaged area.

6. A method for repairing penetration damage to the outer sheath of a high-voltage single-core cable according to claim 1, characterized in that: The specific implementation method of step 3 is: for the damage to the penetration of the cable outer sheath, take corresponding repair measures according to the size of the damage area, where the size of the damage area includes local pit damage and large area damage; The repair measures for local pothole damage are: fill the hole with epoxy mud or the same material as the cable sheath by heating to restore the insulation and sealing performance of the local pothole. The size of the repair should be consistent with the size of the cable outer sheath, and wrap the insulation tape with a range of 60mm in a semi-overlapping manner; The repair measures for large-area damage are: use insulating tape to perform insulation sealing repair, and the size of the repair should be consistent with the size of the cable outer sheath.

7. A method for repairing penetration damage to the outer sheath of a high-voltage single-core cable according to claim 6, characterized in that: The specific implementation method of step 4 is: wrapping the waterproof tape to cover the insulating tape range of more than 60mm to ensure waterproof performance, and then wrapping the black PVC adhesive tape to enhance the wear and corrosion resistance.

8. A method for repairing penetrating damage to the outer sheath of a high-voltage single-core cable according to claim 1, characterized in that: The specific implementation method of step 5 is: wrapping the semi-conductive tape to restore the semi-conductive performance, and the semi-conductive tape overlaps the outer conductive layer of the intact part of the cable on both sides by no less than 50mm to ensure the connectivity of the conductive layer.

9. A method for repairing penetration damage to the outer sheath of a high-voltage single-core cable according to claim 1, characterized in that: The specific implementation method of step 6 is: the insulation performance of the repaired outer sheath should meet the requirement of withstanding a 10kV DC voltage for 1 minute without breakdown.

Images