Construction method of 11KV3-core XLPE high-voltage cable direct connection thermal shrinkage cable joint

Abstract

The invention discloses a construction method for directly connecting a 11KV3-core XLPE high-voltage cable with a heat-shrinkable cable joint. The construction method comprises the following steps: (1) stripping the cable in sequence in a layered manner; (2) roughening a metal surface or an insulating layer surface before the heat-shrinkable sleeve is subjected to heat-shrinkable heating; (3) after the surface is roughened, the surface is cleaned with a cleaning solvent, and the roughened surface is cleaned up; after the cleaned area is coated with sealing sol, the sealing sleeve is heated; (4) when the heat-shrinkable sleeve is subjected to heat-shrinkable heating, a heating tool is uniformly used for moving on the sealing sleeve, and meanwhile, flame needs to be kept to move towards the shrinkage direction; and (5) after the overall shrinkage of the heat-shrinkable tube is finished, repeatedly heating the two ends of the heat-shrinkable tube, so that the sealing sol coated on the inner walls of the two ends of the heat-shrinkable tube is fully hot-melted and sealed. Construction is easy and convenient, and the sealing effect is excellent.

Description

Technical Field

[0001] The present invention relates to a construction method for a directly-connected heat-shrinkable cable joint of a high-voltage cable. Background Art

[0002] As an indispensable and important part of infrastructure construction, the high-voltage power project has received great attention from all parties. The most critical part in the construction process is the connection method of the cable joint. The existing sealing methods often have problems such as unsatisfactory sealing performance and need to be further improved. Summary of the Invention

[0003] The purpose of the present invention is to provide a construction method for a directly-connected heat-shrinkable cable joint of an 11KV 3-core XLPE high-voltage cable with good sealing performance.

[0004] The technical solution of the present invention is as follows: A construction method for a directly-connected heat-shrinkable cable joint of an 11KV 3-core XLPE high-voltage cable, characterized by comprising the following steps: (1) Sequentially and layer by layer, peel the cable, and remove a section of the semi-conductive layer at the end of the cable. During the heat connection process, continuous construction should be carried out. (2) Before heat-shrinking the heat-shrinkable sleeve, roughen the metal surface or the surface of the insulating layer. (3) After roughening the surface, clean the surface with a cleaning solvent to clean the roughened surface. After coating the sealing sol on the cleaned area, heat the sealing sleeve so that the tubes are closely connected to each other and between the tube and the metal, thereby better exhausting the air inside the tube and blocking external moisture. (4) When heat-shrinking the heat-shrinkable sleeve, evenly move the heating tool on the sealing sleeve, and at the same time, keep the flame moving in the shrinking direction, which is beneficial to preheating the pipe material and exhausting the air in the pipe material completely. It is strictly prohibited to scorch the pipe material. (5) After the overall shrinkage of the heat-shrinkable tube is completed, repeatedly heat the two ends of the heat-shrinkable tube so that the sealing sol coated on the inner walls of the two ends of the heat-shrinkable tube is fully melted and sealed until it is seen that the sealing glue overflows from both ends of the tube; after the sealing tube is completely sealed, its surface should be smooth, without wrinkles, bubbles, cracks, or scorching, and the internal structure contour can be clearly shown; the joint part should not be moved until it cools down, otherwise the sealing effect will be affected.

[0005] When heat-shrinking and heating the sealing sleeve at the cable joint in step (4), start heating from the middle position of the connection; evenly use the heating tool, first keep the flame moving in one shrinking direction from the middle position, and after shrinking, then keep the flame moving in the opposite direction from the middle position, so as to ensure that the sealing sleeves at the cable head connection are all shrunk well and ensure the sealing performance of the sleeve.

[0006] Working Environment Requirements: According to the construction site requirements of heat-shrinkable cable joints for cables, the installation temperature should be above 0°C and the humidity should be below 70%. In a low-temperature and humid environment, preheat the cable to make its surface temperature reach 50°C - 60°C.

[0007] The 11V3-core XLPE (cross-linked polyethylene) cable used has a specification of 3×400mm².

[0008] The construction of the present invention is simple and the sealing effect is excellent.

[0009] The connection of cable heads is a key link in the cable laying project. During the production process, it is very easy to be affected by external pollution. It is necessary to strictly follow the technological requirements and operation essentials of heat-shrinkable cable joints for operation, select professional technicians for operation, ensure that the production process is rigorous, methodical, and progressive, so as to greatly improve the reliability and service life of the cable operation. The heat-shrinkable cable joint technology is mature and the construction cost is low, which is suitable for construction operation in the local environment of Abu Dhabi, UAE. Using this technology, the construction goal of low cost and high quality has been successfully achieved.

[0010] The present invention will be further described below in conjunction with embodiments. Specific implementation mode

[0011] A construction method for a 11KV 3-core XLPE high-voltage cable direct-connected heat-shrinkable cable joint includes the following steps: Work preparation: Prepare all necessary materials and related accessory materials; check the availability of all necessary documents, namely approved construction drawings, approved material approval forms and other documents; obtain relevant work permits according to the activities carried out; ensure that the personnel performing the work have good capabilities and relevant work operation qualifications; before crimping, connecting and terminating, check the pulled-out cable: 1) appropriate cable size, type and length; 2) the cable should be reasonably laid, wrapped and tied along the line, and the correct type of cable tie should be used; 3) according to the approved drawings, check the continuity of the cable to verify whether the cable is pulled to the correct destination or position; 4) check whether the temporary cable label is correct and replace it with a permanent label; 5) the cable support is good; 6) if there is cable damage, the owner will be notified.

[0012] Before installation, the construction personnel should carefully read the cable connection instructions and ensure that all required tools are ready. The construction personnel should be familiar with the use, inspection and precautions of various tools. During the installation of cable accessories, the cable core components, construction insulation material tools and construction personnel must be kept clean. The construction site should have sufficient light, be clean and dry. A protective shed should be set up for outdoor construction, and an operation platform should be set up for aerial work. When there are live equipment nearby, safety measures should be taken.

[0013] Working environment requirements: According to the construction site requirements of cable heat shrink cable joints, the installation temperature should be above 0℃ and the humidity should be below 70%, so as to avoid condensation of water on the cable surface at low temperature and high humidity, which will cause water seepage and moisture in the cable. In a low temperature and humid environment, we can preheat the cable to make its surface temperature reach 50℃-60℃, which can effectively avoid the above situation. The average temperature in Abu Dhabi, where this project is located, is above 0℃ and the average humidity is below 70% throughout the year, so the environmental conditions in this area are completely suitable for connecting cables using thermoplastic cable joint technology.

[0014] Sealing construction: The most important thing about cable head connection is the quality of sealing, which determines whether it can pass the final quality acceptance of consultants and relevant departments in the subsequent testing phase. Therefore, when carrying out cable head connection construction, it is necessary to strictly follow the relevant construction instructions and operation manuals, conscientiously improve the quality of the process, and strengthen the quality supervision of the construction personnel's operation.

[0015] At the beginning of the construction, the cable will be stripped layer by layer. After being stripped, the cable will be exposed to the air for a long time, which will cause the cable head to be easily oxidized and contaminated. Therefore, when performing heat shrink connection, a section of the semi-conductive layer at the cable end must be stripped off. During the hot connection process, we must seize the time, uninterrupted construction, and continue to ensure that the cable after hot connection still maintains excellent performance.

[0016] Before heat shrinking the heat shrink tubing, the metal surface or the insulating layer surface should be roughened. The rough surface has more surface area than the smooth surface, which increases the surface area of the sealing sleeve and the contact part, thereby increasing the contact between the sealing sleeve and the sealing area, and the sealing effect is better.

[0017] After roughening the surface, it is necessary to clean the surface with a cleaning solvent to clean the roughened surface. The heat shrink cable joint uses a sealing sol coated on the inner wall of the heat shrink tubing for sealing. The presence of impurities will affect the subsequent sealing work. After the sealing sol is coated on the cleaned area, the sealing tubing is heated, and the tubes and the tubes and the metal are tightly connected, so as to better discharge the air in the tube and block the external moisture.

[0018] When the heat shrink tubing is heated, it should be kept away from the material and the temperature should be strictly controlled. The heating tool should be evenly moved on the sealing tubing, and the flame should be kept moving in the shrinking direction. This is conducive to preheating the tubing and removing the air in the tubing. It is strictly forbidden to burn the tubing.

[0019] When heat - shrinking and heating the sealing sleeve at the cable joint, start heating from the middle position of the connection. Use the heating tool evenly. First, keep the flame moving towards one direction of shrinkage from the middle position. After shrinkage, then keep the flame moving in the opposite direction from the middle position. This can ensure that the sealing sleeves at the cable head connection are all well - shrunk and ensure the sealing performance of the sleeve.

[0020] After the overall shrinkage of the heat - shrinkable tube is completed, the two ends of the heat - shrinkable tube should be reheated repeatedly so that the sealing sol coated on the inner walls of the two ends of the heat - shrinkable tube is fully melted and sealed until the sealing glue overflows from both ends of the tube. After the sealing tube is completely sealed, its surface should be smooth, without wrinkles, bubbles, cracks, charring, and the internal structure contour can be clearly shown. Do not move until the joint part has cooled, otherwise it will affect the sealing effect.

Claims

1. A construction method for directly connecting a heat-shrinkable cable joint of an 11KV 3-core XLPE high-voltage cable, characterized in that: It includes the following steps: (1) Strip the cable layer by layer in sequence. Remove a section of the semi-conductive layer at the end of the cable. During the heat connection process, continuous construction should be carried out without interruption; (2) Before heat shrinking the heat shrinkable sleeve, roughen the metal surface or the insulation layer surface; (3) After roughening the surface, clean the surface with a cleaning solvent to clean the roughened surface; After applying the sealing sol to the cleaned area, heat the sealing sleeve. The tubes are in close contact with each other and with the metal, so as to better expel the air inside the tube and block the external moisture; (4) When heat shrinking the heat shrinkable sleeve, evenly move the heating tool on the sealing sleeve, and at the same time keep the flame moving in the shrinking direction. This is beneficial for preheating the pipe material and exhausting the air in the pipe material. It is strictly prohibited to scorch the pipe material; (5) After the overall shrinkage of the heat shrinkable tube is completed, repeat heating the two ends of the heat shrinkable tube to fully melt and seal the sealing sol coated on the inner walls of the two ends of the heat shrinkable tube until the sealing glue overflows outside the two ends of the tube; after the sealed tube is completely sealed, its surface should be smooth, without wrinkles, bubbles, cracks, or scorching, and the internal structure contour should be clearly visible; it can only be moved after the joint part has cooled down, otherwise the sealing effect will be affected.

2. The construction method of the directly-connected heat-shrinkable cable joint for the 11KV 3-core XLPE high-voltage cable according to claim 1, characterized in that: In step (4), when heat shrinking and heating the sealing sleeve at the cable joint, start heating from the middle position of the connection; evenly use the heating tool, first keep the flame moving in one shrinking direction from the middle position, and after shrinking, then keep the flame moving in the opposite direction from the middle position. This can ensure that the sealing sleeves at the cable head connection are all shrunk well and ensure the sealing performance of the sleeve.

3. The construction method of the 11KV 3-core XLPE high-voltage cable direct-connected heat-shrinkable cable joint according to claim 1 or 2, characterized in that: the work Environmental requirements: According to the construction site requirements for heat shrinking cable joints of cables, the installation temperature should be above 0°C and the humidity should be below 70%. In a low-temperature and humid environment, preheat the cable to make its surface temperature reach 50°C - 60°C.