Operation and repair of cable lines. Cable line repair

During the operation of cable lines (CL), damage may occur in cables, couplings or seals. The damage is in the nature of an electrical breakdown.
During routine repairs of cable lines, the following work is performed: inspection and cleaning cable channels, tunnels, routes of openly laid cables, end funnels, couplings, straightening of cables, restoration of lost markings, determination of cable heating temperature and monitoring of corrosion of cable sheaths;
checking grounding and eliminating detected defects; checking access to cable wells and the serviceability of well covers and locks on them;
re-laying of individual sections of the cable network, high-voltage testing (for cables with voltages above 1 kV or checking insulation with a megohmmeter for cables below 1 kV), replenishing funnels and couplings with cable mastic, repairing cable channels.
When overhauling cable lines, perform the following:
partial or complete replacement (as necessary) of sections of the cable network, painting of cable structures, re-cutting of individual end funnels, cable couplings, replacement of identification marks, installation of additional mechanical protection in places of possible cable damage.
Repair of cables laid in trenches. If it is necessary to replace the cable line or part of it, the opening of the improved coatings is carried out with electric concrete concrete S-850 or electric hammer S-849, motorized concrete concrete concrete S-329, pneumatic concrete concrete compound S-358.
The covering material is thrown onto one side of the trench at a distance of at least 500 mm from the edge, and the soil onto the other side at a distance of at least 500 mm from the edge. The trench is dug straight, and at turns - expanded to ensure the laying of cables with the required radius of curvature.
Trenches, in the absence of groundwater and underground structures, are dug without fastening vertical walls to the depth indicated below (in m):
In sandy soils................................................... ................................................. 1
In sandy loams........................................ ........................................................ ........................... 1.25
In loams, clays.................................................... ........................................................ 1.5
In particularly dense soils................................................... ........................................................ ..2
Trenches in areas where people and vehicles move are fenced off and warning signs are installed near them, and additional signal lighting is installed at night. The distance between the fence and the axis of the nearest rail on a normal gauge railway track must be at least 2.5 m, and on a narrow gauge railway track - at least 2 m.
Before laying new cables in a trench, the following work is performed: secure the pipes in the trench at places where the route intersects and approaches roads, underground communications and structures; remove water, stones and other objects from the trench and level its bottom; make a 100 mm thick bedding at the bottom of the trench with fine earth and prepare fine earth along the route for dusting the cable after laying; bricks or reinforced concrete slabs are prepared along the route to protect the cable when such protection is necessary. Materials that are susceptible to rotting and decomposition in the ground (wood, sand-lime brick, etc.) cannot be used to protect cables.
At places of intersection and convergence with engineering structures, concrete, reinforced concrete, ceramic, cast iron or plastic pipes are used. Steel pipes are used only for passing a section of the route using the pound puncture method.
The laying depth for cables with voltages up to 10 kV from the planning mark should be 0.7 m. Before laying the cable, an external inspection of the upper turns of the cable on the drum is carried out. If damage is detected (dents, punctures in the turns, cracks in the mouth guard, etc.), cable laying is allowed only after cutting out the damaged areas, checking the insulation for moisture and soldering new mouth guards to the ends of the cable. During repair work, unrolling the cable from the drum is most often done using a winch.
Permissible tensile forces for cables with voltages up to 10 kV are given in table. The tensile force when unrolling a cable with a voltage of up to 10 kV is controlled using a dynamometer by two experienced fitters who are located at the drum and monitor the unwinding of the cable.
Permissible tensile forces when rolling out for cables up to 10 kV

* Pulling of cables with plastic and lead sheaths is allowed only by the cores. ** Core made of soft aluminum with a relative removal of at least 30%.
Cables are laid with a margin equal to 1-3% of its length (snake), to eliminate dangerous mechanical stresses during soil displacements and temperature deformations, cable laying with a snake when pulled by a winch is carried out after finishing rolling from the drum during the process of laying the cable to the bottom of the trench. When laying cables in parallel in a trench, their ends, intended for subsequent installation of couplings, are positioned with a shift of the connection points of at least 2 m. At the same time, a reserve of cable ends is provided along the length necessary for checking the insulation for moisture, installing couplings and laying the compensator arc , protecting the couplings from damage in the event of possible soil displacements and temperature deformations of the cable, as well as in case of re-cutting of the couplings if they are damaged.
In cramped conditions with large flows of existing cables, it is possible to place expansion joints in a vertical plane, placing the couplings below the cable laying level. The number of couplings per 1 km of replaced cable lines should be no more than 4 pcs. for three-core cables 1-10 kV with a cross-section of up to 3 x 95 mm 2, and 5 pcs with a cross-section of 3 x 95 * 2 x 240 mm 2.

Replacement of cables in blocks.

Replacement of defective cable lines is carried out, as a rule, by using the reserve holes of the block sewer system. The well is inspected by two electricians under the supervision of the work manager (foreman). In this case, one electrician in an electrician's belt with a rope tied to him is lowered into the well, and the second electrician, who has the end of the rope in case he helps the first, remains outside at the open hatch of the well.
To avoid an explosion, when working in wells, you must not smoke, light matches or use open fire. When working in a well, you can use portable lighting lamps with a voltage not exceeding 12 V. A fence in the form of tripods with warning signs and lanterns is installed above the open hatches of the wells.
The maximum permissible tensile forces of cables of brands V V G, AVEG, VRG and AVRG with the rope fastened by the cores can be taken according to table. with a coefficient: for small veins - 0.7; for aluminum conductors made of solid aluminum - 0.5; for aluminum conductors made of soft aluminum - 0.25. To reduce the tensile forces when pulling the cable, it is allowed to use a lubricant that does not contain substances that have a harmful effect on its sheath (grease, grease). Grease consumption is 8-10 kg for every 100 m of cable.
The cable is pulled at a speed of 0.6-1 km/h and, if possible, without stopping, in order to avoid large pulling forces when moving the cable. After the pulling is completed, the cable is laid in a well on supporting structures, its ends are sealed, and elastic linings (for example, sheet asbestos) are placed in all places where the cable exits the channels of the block to protect its shell from abrasion.

Rolling out cables in a tunnel using rollers:
1 - drum with cable; 2 - corner guides; 3 - linear spacer rollers; 4 - corner rolling roller; 5 - cable; b - winch cable
After installation, the couplings in the well are placed in a detachable protective fireproof casing.
At the inputs of blocks in a building, tunnels, etc., the holes in the blocks after laying the cables are sealed with fireproof and easily destructible material. In places where cables come together at a distance less than permissible (for example, in places where cables exit pipes, at intersections, etc.), asbestos-cement rings are put on the cables.

Replacement of cables in cable rooms.

In cable rooms, it is allowed to lay only cables without an outer combustible cover, for example, cables that have a fireproof fibrous cover over the armor or a fireproof hose made of polyvinyl chloride or other materials equivalent in fireproofing, as well as cables with a fireproof sheath.
If a cable with a combustible outer cover is used during replacement, then the cover is removed along the entire route inside the cable structure to the very point of exit from the pipe or opening. Due to fire safety conditions, unarmored cables with a polyethylene sheath cannot be laid indoors.

Replacement of cables in industrial premises.

Only armored cables without a combustible outer covering and unarmoured cables with a fireproof sheath can be laid inside production premises. In rooms with an aggressive environment, cables with polyvinyl chloride and other sheaths that are resistant to exposure to aggressive environments are used.
Lifting and laying of new cables on trays and boxes in short sections of the route is carried out from mobile towers, platforms, scaffolding, stepladders, etc. Cables on trays are laid in one row. You can lay cables without a gap between them, as well as in bundles close to each other in 2-3 layers (in a bundle) and, as an exception, in three layers. The outer diameter of the bundle should be no more than 100 mm.
In boxes, cables and wires are laid in multilayers with arbitrary relative positions. The height of the layers in one box should not exceed 150 mm.

Features of the use of AAShv cables.

Cables of the AAShv brand are used in accordance with the “Unified Technical Guidelines for the Selection and Use of Electrical Cables”. These cables are not laid or rewound at ambient temperatures above + 30°C and below - 20°C.
For any type of installation, the cable route must have a minimum number of turns, as a rule, no more than three per construction length, not counting turns when introducing the cable into a building and structures. Laying cables in pipes is allowed only in straight sections no longer than 40 m and at entries into buildings and cable structures.
The internal diameter of pipes used for laying AASHA cables must in all cases be at least twice the diameter of the cable. To protect cables from mechanical damage in vertical sections, sheet steel casings are used.
In existing cable structures under difficult conditions, the manual method is used for mechanized installation. When laying cables manually, friction against the ground, floor, walls, etc. must be avoided. Unloading, loading and transportation of AAShv cable at temperatures below - 10°C is carried out with extreme caution.
When heating the cable with a three-phase current, all cable cores are short-circuited at its inner end, and when using a single-phase or DC, in addition, two cable cores at its outer end. One wire of the circuit should be two wires connected to each other in parallel, and the second wire should be the third wire of the cable. The current values ​​when heating the cables are given in table.

Permissible current values ​​when heating cables, A

Repair of cable protective hose brand AAShv.

Repair of damage to the protective hose is carried out by welding in a stream of hot air at a temperature of 170-200°C using a welding gun with electrically heated air or a gas-air gun. Compressed air is supplied at a pressure of 0.98 * 104 - 3.9 * 104 Pa from a compressor or compressed air cylinder.
A polyvinyl chloride rod with a diameter of 4-6 mm is used as a welding additive. Before welding, areas to be repaired are cleaned with a cable knife, foreign inclusions are cut out, and protruding edges and burrs in areas where the hose is damaged are cut off. Hose breaks are repaired using polyvinyl chloride patches or split cuffs.
The patch is made of plastic so that its edges overlap the tear site by 1.5-2 mm. The patch is welded along the entire perimeter to the hose, then a filler rod is welded along the resulting seam, and the protruding surfaces of the rod are cut off and the seam is leveled at the welding site.
When repairing a hose using a split cuff, cut off a piece of polyvinyl chloride tube 35-40 mm longer than the length of the damaged area, cut the tube lengthwise and put it on the cable symmetrically to the damaged area. The cuff is temporarily secured with polyvinyl chloride tape in increments of 20-25 mm, the end of the rod is welded at the junction of the cuff with the hose, and then the rod is laid and welded around the end of the cuff. Remove the fastening tapes, weld the rod along the cut of the cuff, cut off the protruding surfaces of the rod and make the final alignment of all welds.
When repairing punctures, small holes and cavities, the damage site in the hose and the end of the filler rod are heated for 3-5 seconds with a stream of hot air, the end of the rod is pressed and welded to the hose at the place of heating. After cooling, making sure that the rod is welded firmly, it is cut off.
In order to seal the hose and level the weld seam, the repair site is heated until signs of melting appear; a piece of cable paper folded in three or four layers is pressed to the heated area. For reliability, the operation is repeated 3-4 times.
When the cable is laid open, the hose can be repaired by winding it in at least two layers, with overlapping adhesive PVC tape and coated with PVC varnish No. 1.

Connection and termination of cable cores and wires.

Contact connections of current-carrying conductors can be made by crimping, welding or soldering.
Technological operations for connecting and terminating cables during repair are similar to those during installation and are discussed in detail above.
When repairing KL armor, the damaged part is removed, the cut armor is soldered to the lead sheath, and the part not covered with armor is protected with an anti-corrosion compound. If it is necessary to repair the cable sheath, then inspect the belt insulation on both sides of the damage site and check the top layer of insulation for the absence of moisture. To do this, remove the paper insulation tapes from the damaged cable and immerse them in paraffin heated to 150°C. Crackling and foaming indicate moisture penetration into the cable under the lead sheath. If there is no moisture inside the cable, a cut lead pipe with two filling holes is placed on the damaged part of the sheath. The pipe is made of rolled lead (two halves). It should be 70-80 mm larger than the bare part of the cable. After filling with hot mastic, the pipe is sealed along the seam and a copper bandage is applied to it, which is soldered to the lead sheath. If there is moisture inside the cable, the damaged area is cut out.

Control questions

1. What kind of work is performed during routine repairs of cable lines?
2. What kind of work is performed during major repairs of cable lines?
3. How are sections of cable lines connected?
4. What technological methods are used when terminating cables?

Failure of cable lines can be caused by various reasons, from natural wear and tear of insulation and mechanical damage to the cable to errors in calculations and incorrect actions of maintenance personnel. In turn, damage to cable lines often leads to emergency situations, fires, fires and damage electric shock. To prevent such consequences, you need to regularly measure the insulation resistance of cables. There are two ways to solve this problem:

1. Provide a staffing schedule of specially trained people with the clearance group necessary to implement maintenance and repair of cable communication lines and power cables.
2. Entrust such work to professionals by concluding a contract for the maintenance of cable lines.

Repair of power cable lines

If the power cable is damaged, the power supply through it is stopped. In this case you need:

• Determine and eliminate the cause of cable damage so that when power is supplied after repair work, the already repaired section does not fail.
• Using special instruments, find the location of the cable damage.
• Repair the cable line. Depending on the extent of the damage, it may be local or require replacement of the entire section of the cable line. Cable workers perform the necessary mechanical work on the cable route (open/close the trench, install couplings, cut/strip the cable, etc.). At the same time, they actively interact with electrical laboratory workers, who indicate the problem area, perform ongoing monitoring and final checks before applying voltage.

Installation and repair of power cable lines 10/ 6/ 0.4 kV must be carried out by trained specialists with appropriate approvals. To eliminate the damage, you should cut the cable in the damaged area and install a connecting cable sleeve. It is used for reliable connection, termination or branching of power cables, as well as for their connection to overhead power lines and electrical devices.

In the process of cutting a cable, all its layers from the outer sheath to the phase insulation of the current-carrying core are sequentially removed with some shift. This is done to further strengthen or restore the insulation or replace the damaged area with an insert. Installing a coupling is a complex and responsible job that allows you to restore the properties of a cable line lost due to damage. Such operations are performed by electrical installers-couplers who have undergone special training and received permits to carry out such work.

Repair of communication cables

First of all, broken connections are switched to functional pairs, and electrical measurements and a thorough inspection are carried out to determine the area of ​​damage. The cable route is inspected, inspection devices are opened, rupture zones are checked, and air pressure is determined. If the problem area is located within the viewing device, after removing the coupling, this gap is dried.

If individual pairs of cores are damaged, the plinths are opened and viewed from the inside. The conductors are soldered, burrs and solder sagging are smoothed out, the conductor or pin is insulated, the pin is adjusted and other repair operations are performed. The plinth can be dried with hot air or washed with cable mass. Broken terminals require replacement. Upon completion of the repair, the operation of the connections is checked.

Repair of fiber-optic communication line (FOCL)

Repair of high-voltage cables up to 10 kV, repair of cable lines.

Comprehensive repair of 0.4 kV cable (basic) - from 52 thousand rubles.
Comprehensive repair of 6/10 kV cable (basic) - from 61 thousand rubles.
Repair of one place of cable damage 380 volts - from 6 thousand rubles.
Repair of one place of cable damage 6000/10000 volts - from 11 thousand rubles.

The highest quality of work for a very reasonable price - the choice of a real businessman!

The company's field team will detect the malfunction and professionally will fulfill cable repair, the need for which is due to any of the following reasons:

• Mechanical damage during work in the laying area;
• Defects present on the couplings, both connecting and end;
• Previously committed violations of installation technology;
• Movements and/or subsidence of the soil;
• Local overheating of structural elements made of metal;
• Cable line repair, the failure of which is due to hidden manufacturing defects;
• Aging of existing insulating shells due to long periods of their operation or resulting overloads.

We provide prompt power cable repair services, operated under loads up to 0.4 kV, and also carry out a full range of repair work on high-voltage cables up to 6 kV inclusive. Our teams carry out basic options repair of 10 kV cable.
Moreover, all of the above is done exclusively with our own materials, the quality of which we are confident in. That's why they price is already included in the cost of the work we perform. The customer will not have to make any additional payments.

• Comprehensive cable repairs are carried out by our team in Moscow.
• It is also possible to travel to other areas, but subject to prior agreement on the details of the work with the operator.
• Cable repair work is carried out depending on the cause of its damage and location.
• Our company's mobile team will arrive at the site of the line damage in short time after submitting the application and will carry out all the necessary work.
• We guarantee high quality work at a reasonable price.

Comprehensive repairs and cable restoration carried out by the company's field team on site Moscow and Moscow region.
At the same time, work on repairing the power cable can be carried out using several methods, depending on the cause of the malfunction and the location of its detection. In each specific case power cable repair may include:

• search for a specific location of the malfunction (damage to the cable line), which is carried out step by step in several stages;
• excavation work to provide access to the damage site;
• performing the actual repair work (restoration of the armor cover, end seals, couplings, shells, etc.);
• carrying out tests of the restored area with registration of their results in the appropriate protocol.

Power cable repair(CL), which can be performed by us, in addition to the procedures listed in the price list, can be supplemented, at the request of the client, with the following technical activities:

1. Detection of a specific short circuit point, break or other damage to a single cable and/or cable line up to 10 kV inclusive.
2. Installation of end and/or connecting sleeves (heat shrink) for repair of 10 sq.m. power cable.
3. Maintenance and repair of cable lines with the subsequent organization of monitoring their insulation for the presence of moisture.
4. Carrying out testing and electrical measuring work to determine the presence of leakage currents in cable insulation and the integrity of the latter. With subsequent registration of the results in a protocol confirming them.
5. High voltage cable repair on the territory of Moscow.

By ordering work from us, you save time, money and receive a guaranteed high-quality solution to your problem. We respect our customers and our own business reputation!

Repair of power cable with installation of a coupling

There are quite a few reasons why cables, connectors, and terminations can fail. These are: various mechanical damage, installation defects, soil settlement, corrosion of the metal sheath of the cable, manufacturing defects, insulation aging and others. In accordance with the requirements of the relevant documents, all cable lines must be subject to repair (routine or major).

Repair of power cable 0.4-6-10 kV

Routine cable repair can be:

• Urgent- repair of power cables and installation of cable couplings or other types of work that are carried out in the event of deprivation of automatic backup power to receivers of category I or especially important category II, while receivers of all categories are overloaded or limit consumers. Urgent repair of cable lines 0.4 kV or 10 kV carried out by the repair team during the working day. The basis for its implementation is the instruction of the energy service management.
• Emergency- repair of 10 kV or 4 kV cable lines when the cable line is disconnected and deprived of voltage to consumers of all categories without the possibility of supplying it via high or low voltage cables or temporary hose cables. The need for emergency repairs also arises when backup line is heavily overloaded and requires limiting consumers. Emergency cable repairs are carried out immediately and continue until the cable line is put into operation.
• Planned- repair of 0.4 kV cable lines, as well as any repair of 10 kV cable lines, in cases not indicated above, carried out according to a pre-drawn up plan approved by the management of the energy services. This schedule is drawn up monthly, taking into account the entries in the inspection and walkthrough logs, the results of measurements and tests, and information from dispatch services.

When performing cable repairs, there is a need to carry out such type of work as installation of cable joints. What is it and what is it used for?

Installation of cable couplings: connecting and end joints

Cable sleeve is a device used for making connections, branching cables, as well as for connecting them to various electrical equipment and power lines.

Installation of the end coupling required when connecting cables to overhead power lines or to outdoor and indoor devices.

Installation of couplings is necessary when connecting two cables.

Installation of cable sleeve is carried out after preliminary cutting of the factory insulation at the ends of the cables. In this case, the outer jute cover, armor, cushion made of paper or fiber, which is located under the armor, insulation (general and each core) are removed. Installation of cable sleeves for paper-insulated cables, a moisture test is required. If moisture is detected, then the cable section is cut out, is replaced with a new one and The coupling is being installed on the cable.

During their operational life, various damage may occur on cable lines, which requires elimination. cable repair.

In accordance with the requirements of the “Instructions for the use of power cable lines. Part 1. Cable lines with voltage up to 35 kV” each cable line must undergo routine or major repairs.

Maintenance can be emergency, urgent and planned.

Emergency repair is such a repair when, after disconnecting the cable line, consumers of all categories are left without voltage and there is no way to supply voltage via high or low voltage cables, including temporary hose cables, or when the backup line to which the load is transferred is unacceptably overloaded and there is no the possibility of further unloading or whether consumer restrictions are required.

Urgent repair is such a repair when receivers of the first or especially important second category are deprived of automatic backup power, and for receivers of all categories, the load on the remaining cable lines causes their overload or limitation of consumers. Repair teams begin urgent repairs of cable lines at the direction of the energy service management during the work shift.

Planned repair is the repair of all cable lines not listed above, which is carried out according to a schedule approved by the management of the energy service. The cable line repair schedule is drawn up monthly based on entries in walk-through and inspection logs, test and measurement results, as well as data from dispatch services.

Major renovation cable lines are carried out according to an annual plan, developed annually in the summer for the next year based on operating data. When overhauling a cable line, perform partial or complete replacement of sections of the cable network, painting of cable structures, re-cutting of individual end funnels, cable couplings, replacement of identification marks, installation of additional mechanical protection in places of possible cable damage.

When making a plan overhaul the need to introduce new, more modern types of cables and cable fittings is taken into account. It is planned to repair cable structures and all work related to the serviceability of lighting, ventilation, water pumping devices, and fire fighting equipment. The need for partial replacement of cables in certain areas that limit throughput lines or that do not meet the requirements of thermal resistance in changed operating conditions of the network with increased short circuit currents.

Repair of cable lines in operation is carried out directly by the operating personnel themselves or by the personnel of specialized electrical installation organizations. When repairing operating cable lines, preparatory work is carried out, preparation of the workplace, and preparation for installation.

Cable line repairs are simple, which do not require much labor and time, and complex when repairs continue for several days

Complex repairs are carried out by one or several teams, and, if necessary, around the clock, using earth-moving mechanisms and other means of mechanization. Complex repairs are carried out either by the energy service of the enterprise (city networks), or with the involvement of specialized organizations for the installation and repair of cable lines

Installation cable sleeve performed if the cable insulation is broken. The coupling is intended to connect different types cable. The installation of a connecting coupling is used when carrying out repair work on damaged cable lines to ensure a reliable and durable connection of different cables, insertion into the network, and relocation of the cable line.

Installation of the coupling on the cable must be carried out carefully, in compliance with technical requirements. If the coupling is installed unprofessionally, without following a certain technology, as well as if the cross-section is incorrectly selected or the voltage does not match, damage may occur. Regardless of what kind of couplings are used - connecting, transition or cable end couplings, they must be of high quality.

All repair work (installation of cable boxes, cable replacement, etc.) must be carried out by professional specialists who have access to such work and the appropriate experience.

Proper organization of maintenance work, professional repair power cable, proper installation of the coupling, timely identification of problem areas and defects ensure long-term operation of cable lines and their reliable uninterrupted power supply.