Basic principles of fiber optic cable (FOC) suspension technology

Recently, the most popular method of constructing fiber-optic lines has become the option of suspending fiber-optic fiber optics on the power transmission line supports of power engineers, contact network supports and self-blocking power lines railway transport, as well as on supports lighting network and ground electric transport. In my graduation project, I chose the type of gasket - suspended, the choice was made due to the advantages indicated below. The projected Ufa - Kazan line will be built along the highway on power transmission line supports (the length of the highway is 525 km). Thus, when modeling the fiber-optic link, I had a margin of 25 km. The suspension of the FOC is carried out on already installed supports and does not require careful preliminary preparation laying routes, therefore more technologically advanced and simpler than laying in the ground. The experience of constructing fiber-optic lines of the Ministry of Railways of the Russian Federation shows that the cost of construction using a fiber-optic cable suspension is 30-35% cheaper than construction with laying a fiber-optic cable into the ground, while construction time is reduced by 2.5-3 times. A special feature of the use of fiber optic cables for suspension on supports is the ability of the cable to have elastic longitudinal stretching of up to 1.5% without causing loads on the optical fiber. For the construction of fiber-optic lines using the method of suspending cables on railway transport supports, only a dielectric self-supporting fiber optic cable is used. During operation, this cable experiences significant fluctuations in temperature, wind and precipitation speeds, and vibrations, which places certain demands on suspension technology. One of the main ones is the principle of limiting the mechanical effects on the shell, the tensile strength of the fiber optic cable, compressive loads, as well as the angles of rotation of the fiber optic cable route. The FOC suspension technology should ensure the safety of the cable sheath coating during pulling from damage.

Modern FOC suspension technology involves two stages:

The preparatory stage, which includes general construction work, replacement of defective and damaged supports, installation of additional supports, ordering and purchasing special mounting brackets for fiber optic cables in accordance with the types specified in the project, brackets for securing cable supplies and optical couplings, anchorage units.

At the second stage, associated directly with the suspension of the fiber optic cable, the following is carried out: fastening the brackets to the supports; mounting technological rollers on the brackets for pulling the cable leader, and then using it and the cable; replacing rollers with special tension or support clamps and cable fastening; installation of couplings; installation of anchors and fastening of FOC reserves; connecting the cable to cross-connect equipment; measurement and certification of the passive part of fiber optic lines. All work on hanging the fiber optic cable on supports is carried out in accordance with current rules and regulations, as well as technical specifications included in the projects.

When constructing fiber-optic lines using the method of suspension on supports of high-voltage communication lines, the following is also used:

Optical cable of small diameter, which, using special mechanisms, is wound with a certain winding pitch onto a phase wire or lightning protection cable;

A special optical cable built into the ground wire (as a rule, is used only when reconstructing a high-voltage line with replacement of the ground wire);

Suspension of optical cables to steel rope(cable) stretched between pillar supports on consoles;

Cable suspension with built-in cable on specially designed consoles.

In any of these methods of FOC suspension, the specified optical parameters must be ensured throughout the entire service life (less than 25 years).

Economic part

Modern transport systems to increase capacity optical lines use multichannel multiplexers. Multiplexers help save significant money by transmitting information at different wavelengths over a single line, thereby making the installation of new fiber optic lines unnecessary.

The cost of a fiber-optic network today amounts to tens and hundreds of millions of rubles, and its creation requires solving more than 50 diverse technical and organizational problems that must be coordinated in time and have guaranteed logistics. Therefore, the success of a network project depends, first of all, on the organization of work. Violation organizational structure project execution dramatically reduces the quality of work.

A typical price structure for fiber optic communication lines, which today are often built along a highway or railroad bed, has the following distribution of funds (in percentage):

Project management ~ 1-3%

design ~ 1-3%

equipment, including system integration into a single network structure + cost of optical cable ~ 75%

construction of fiber optic lines ~ 6 - 10%

creation of a control center and operation service ~ 8 - 10%

training ~ 1-2%

unforeseen (other) expenses ~ 2 - 4%

In general, you additionally need to take into account the costs of customs duties ~ 5-20%, taxes ~ up to 20% of the cost of equipment and network operating costs, which in the first year can be up to 10%.

Let's calculate the cost of the designed line.

The length of the fiber-optic line is 550 km, the information transmission speed is 2.5 Gbit/s (STM-16).

Equipment - 8-channel transport system WL8 - Siemens company.

Optical cable - OKLZh - Samara company, using various types of Corning fibers.

Since the thesis project demonstrated the possibility of designing a communication line using both standard single-mode fiber and single-mode NZDSF fiber, the cost of the project can be calculated for two types of fibers.

Optical cable cost:

When using standard single-mode fiber SMF28 from Corning, 1 km of optical cable will cost 90,000 rubles. The entire line of 550 km will cost 90,000*550 = 49,500,000 rubles. One MCD module (dispersion compensating fiber) will cost 200,000 rubles, 4 modules will be required, i.e. - 800,000 rubles. We use a Corning DCM-95 module.

When using single-mode NZDSF fiber LEAF TM from Corning, 1 km of optical cable will cost 120,000 rubles. The entire line of 550 km will cost 120,000*550 = 66,000,000 rubles.

Equipment - the Siemens WL8 transport system will cost ~ 9,000,000 rubles.

The total cost of equipment + optical cable will be:

1st case - 59,300,000 rubles,

2nd - 75,000,000 rub.

As mentioned above, the cost of fiber-optic communication lines equipment is approximately 75% of the total construction costs of the project.

59 300 000 - 75 %

Cost - 100%

Cost = (59,300,000 * 100)/ 75 = 79,000,000 rub.

75 000 000 - 75 %

Cost - 100%

Cost = (75,000,000 * 100)/ 75 = 100,000,000 rub.

Let's calculate the payback period of the designed line:

The price of one STM-16 channel per hour is 600 rubles. Let's calculate per day: 600 * 24 = 14,400 rubles. Since the line is 8-channel: then per day - 115,200 rubles.

Let's calculate the amount for the year: 155,200 * 365? 42,000,000 rub.

Let's take into account that the system is not always 100% loaded. Let's calculate the amount when the system is 80% loaded, from here

42 000 000 - 100 %

For a year - 80%

For the year = (42,000,000 * 80) / 100? 33,000,000 rub.

From the results obtained, we conclude that the line I am designing in the 1st case will pay for itself in approximately 2.5 years, in the 2nd case in approximately 3 years.

As mentioned above, you need to take into account customs duties when importing equipment, payment of taxes - up to 20% of the cost of the entire system, salary costs service personnel, the costs of operating the network, which in the first year can be up to - 10%.

Taking into account the above, the payback period approximately doubles, i.e. it will be 5 and 6 years, respectively, in the first and second cases.

Safety precautions

As a safety precaution when modeling FOLSV on a computer, you can use the ergonomics of the computer operator’s workplace.

The operator's workplace must meet certain requirements, ensure maximum comfortable working conditions at the computer, and contribute to maintaining efficiency and well-being throughout the day.

The computer operator's workplace includes:

The monitor is the main security element in the desktop computing system. A bad monitor can become a very real threat to human health. At the same time the monitor High Quality thanks to high technical data and low level electromagnetic radiation increases productivity, prevents visual fatigue, fatigue and headaches. The monitor must meet the requirements for viewable screen size, resolution, frame rate, multi-frequency, screen coverage and screen setup. The frame refresh rate is at least 75 Hz at the optimal resolution for each class. The monitor must fully comply with the MPRII, TCO standards and safety requirements established by GOST R50948-96 “Media for displaying information for individual use”, in terms of the level of alternating electromagnetic and electrostatic fields.

keyboard and mouse

The keyboard is the main input device and its design determines how quickly the operator gets tired and, consequently, labor productivity. The disadvantage of the keyboard is the rapid fatigue of the hand during long-term work, since the hand is always suspended, which creates a load on the muscles of the forearm.

Special attention of specialists in the field of ergonomics is attracted by the mouse-type manipulator. The disadvantage of all mouse manipulators is that every time you raise your hand and repeatedly hold it over some object, the forearm experiences a significant load. There are movable hand rests on the market that move with your arms. These supports are placed so that the hands hang freely from them, which reduces stress on the forearm and reduces fatigue.

desk and chair

When working with a computer, work furniture plays an important role in creating optimal conditions human work. Its proper use can reduce the degree of fatigue, increase efficiency, productivity, and concentration.

Computer furniture should be comfortable, durable, reliable, and have a neat appearance. In this case, the design and dimensions of the table and chair should contribute to the optimal posture of the operator, in which certain angular relationships between the “hinge” parts of the body are maintained. Correct posture (and therefore correct functioning body) will help maintain health and prevent symptoms of computer stress syndrome, as well as symptoms of constant stress.

conclusions

Only correct compliance with the requirements and measures to optimize the work of a computer operator allows one to maintain not only normal performance, but also, most importantly, health.

After all, the entire development of measures to optimize the working conditions of a computer operator is intended to prevent the adverse effects on humans of harmful factors that accompany work with video display terminals and personal electronic computers.

One of the important characteristics design self-supporting cables are permissible external mechanical loads, such as wind, ice and self-weight load. Therefore, one of the most important decisions when building a fiber-optic line is the choice of a fiber-optic cable of an appropriate design that could withstand the various stresses that arise in the cable during construction and operation. These cable parameters can be determined using the method proposed by Incab CJSC.

The speed of construction is very high. You can hang one or two construction lengths of cable in one shift.

The cost of the cable is also not very high and, on average, for light construction options ranges from $2800 to $3600/km.

Having built a fiber-optic line in this way, you need to think about how long it will last and what needs to be done to make it last longer? FOCL based on a self-supporting cable is exposed to a wide variety of influences, primarily atmospheric factors - wind loads, solar radiation, precipitation, icing, mechanical damage caused repair work on other wires, or cable theft. Moreover, if the cable hangs in an electric field (which happens everywhere), then as a result of the influence solar radiation Microcracks begin to appear on the surface of the outer moisture-proof sheath of the cable, in which dirt and moisture accumulate and the tracking process begins to develop - the flow of surface currents - tracks. Over time, the density of these currents increases and the cable gradually begins to burn. This is especially evident in the places where the cable is attached to the supports, since the cable is not grounded in the span and enough high density tracks, and on the support the cable is grounded and surface currents naturally flow down the support. The only recommendation to reduce the influence of this factor is the use of a tracking-erosion-resistant moisture-protective shell based on fluoropolymer materials.

As a result, the service life of fiber optic lines based on self-supporting fiber optics does not exceed 18–20 years.

5.4. Features of hanging a self-supporting fiber optic cable on the supports of the electric railway contact network

Suspension of self-supporting fiber-optic communication cables on contact network supports and high-voltage automatic blocking lines is carried out taking into account the requirements of the "Rules for Construction and technical operation contact network of electrified railways” approved by the Ministry of Railways of Russia.

The suspension of the fiber optic cable is carried out on the operating metal or reinforced concrete supports of the contact network, provided that the load-bearing capacity of these supports is sufficient to absorb all the existing loads from the suspended fiber optic cable, and the location of the fiber optic cable on the supports ensures the possibility of working on it in the presence of voltage in the contact network.

The suspension of the fiber optic cable on the contact network supports is carried out from the field side. In exceptional cases, in agreement with the railway power supply service, it is allowed to hang the fiber optic cable from the inside of the supports (from the track side). The distances from the lowest point of the fiber optic cable at maximum sag to the ground surface, as well as the distance to other wires and parts of the contact network, must be no less than the established values.

The suspension of the fiber optic cable on the contact network supports is carried out on brackets, the location of which on the supports is determined by the design. Brackets on supports along the route are usually installed at the same height from the rail head. The brackets are fastened to reinforced concrete supports using clamps. When using a FOC with a metal core or with metal armor, all brackets must be connected to a protective ground circuit. When hanging a FOC with a dielectric core, grounding is not performed. Attaching the brackets to metal supports made using hook bolts or special parts.

Work on the suspension and installation of a fiber optic cable can only begin if there is a detailed design approved by the customer for the construction of a fiber optic cable line and permission from the railway power supply service to carry out work in the area of the contact network and the high-voltage automatic blocking line.

Work on pulling the fiber optic cable can be carried out “from the path” with stress relief, or “from the field” without stress relief.

When working “from the path” with stress relief, high-performance specialized complexes of machines are used, which include:

an AGD type motor carriage for towing cargo trailers, powering traction and braking modules and equipped with an AGP type hydraulic lift for working at heights;

two cargo trailers equipped with traction and braking modules with rotating devices for installing drums with woks and reels with a cable leader.

Traction and braking modules must have devices for regulating the tension force of the fiber optic cable and automatically turning it off when the tension force exceeds the maximum tension value established for a given brand of fiber optic cable.

When working “from the field,” a set of special mechanisms is used, including:

a winch with adjustable tension force for pulling the leader cable and fiber optic cable under tension;

lifting and braking device for lifting and adjusting the height of the cable drum;

a device for installing and braking reels with a cable leader; When using a specialized set of machines for work

“out of the way”, the suspension of the fiber optic cable is carried out in the following sequence. The rope leader is pulled along the rollers pre-hung on the brackets. To do this, after engaging in the hauling complex and relieving tension, one cargo trailer with leader cable reels is installed at the beginning of the anchor section 25–30 m from the anchor support, and the second trailer is in the coupling

With the railcar begins to slowly move towards the first anchor support. Opposite the first anchor support, the railcar stops, the mounting cradle with two assemblers rises to the bracket with the roller. The leader cable is detached from the cradle, passed through the roller and reattached to the cradle. In this position, the railcar slowly moves to the next support. At the next support, the leader cable is again passed through the roller and the movement of the railcar resumes. In this way, the leader cable is stretched throughout the entire section. After passing the rope leader through the roller of the outer anchor support, the railcar with the trailer with cable drums in front of it moves a distance of 25–30 m beyond the last support and stops. While pulling the leader cable, the fitters operating the traction and braking device

With coils, slow down the coils, ensuring rolling the leader cable is under tension.

IN emergency situation The leader cable is connected through a swivel using a cable clamp “stocking” to the fiber optic cable located in the drum on the cargo trailer. The railcar is uncoupled from the trailer with the cable drum and returns to the first trailer with the reels free from the cable leader. The motors of the traction module are turned on from the railcar using a hydraulic drive and the slow pulling of the fiber optic cable begins. In this case, the drum from which the fiber optic is rolled out is slowed down so that the required sag of the fiber optic in the spans is ensured.

When working “from the field” using a set of mechanisms on the side of the track behind the clearance of the contact network supports at the beginning and end of the

of the core section, horizontal platforms are selected at a distance of 25–30 m from the outermost anchor supports. One of them houses a device for installing and braking reels with a leader cable. At the opposite end of the anchor section, a traction winch is installed on the selected site for pulling the fiber optic cable and leader cable. After pulling the leader cable along the entire anchor section, its ends are secured to the outer supports.

To pull the fiber optic cable, a lifting and braking device with a cable drum is installed on the site where the device for reels with a cable leader was located, and then in the same way: the winch is turned on and the fiber cable is pulled along the anchor section.

When working with a set of special mechanisms, the FOC pulling speed should be within 1.8 km/h. During broaching of the FOC, when the stocking clamp approaches the roller and passes through the roller, the broaching speed is reduced to a minimum, almost to a complete stop. Pulling the fiber optic fiber over the rollers, regardless of the use of machines and mechanisms, is performed smoothly with minimal traction force.

After pulling the FOC, they begin work on securing it using various clamps. Work begins with anchoring the fiber optic on the support farthest from the drum.

After hanging the fiber optic cable on the contact network supports or high-voltage line supports, automatic blocking is carried out special work, necessary for the operation of fiber-optic lines. Such work includes:

construction of fiber optic cable inputs into the buildings of communication houses and electrical control posts;

installation of connecting and branching couplings, including fiber welding and welding quality control using instruments;

fastening couplings on supports or other devices with laying out and securing the technological stock of the FOC;

control and measurement work on the installed sections of the fiber optic cable between the regenerators.

5.5. Navigable technology for the construction of fiber-optic lines

Winding a relatively light and inexpensive cable without reinforcement with power elements onto the phase conductors of power lines is one of the original and cheap ways to build fiber-optic lines.

Winding technology for the construction of fiber-optic lines is an alternative method for laying cables in a lightning protection cable. But, unlike laying OK in a lightning protection cable, in this case there is no need to replace the lightning protection cable and remove the power line from the operating condition.

The OC is wound evenly, using special mechanisms, with a certain pitch around the existing lightning protection cable or phase wire using a special winding machine (Fig. 5.11, Fig. 5.15). The winding machine can move along the lightning protection cable either using a radio-controlled self-propelled mechanism or manually using a special winch. To move the winding machine through power line supports, a special lifting device is used.

	The essence of the winding method is
	is as follows. Reel with cable
Rice. 5.11. Implementation	lem is installed on the winding
Rice. 5.11. Implementation	the car, the car is rolling
winding machines	the car, the car is rolling
winding machines

power line wire and simultaneously rotates the
carcass with a cable around the wire, ensuring
when balancing and tensioning the cable
minimal impact on the load-bearing structure
water As a result, the cable (Fig. 5.12) is spiral-		Rice. 5.12. Navive
		Rice. 5.12. Navive
but is wound onto the wire with a constant		fiber optic cables –
naviva step.

Initially, the weight of the machine with cable did not exceed 37 kg, the maximum rotation range of the reel was 0.4 m, the cable reserve on one reel was 1000 m (for a cable d = 6.5 mm), i.e., when using a cassette of two reels, the maximum construction length is 1 km. The machine is driven by a tow rope, manually, from the ground. The speed of movement of the machine along the wire is about 0.5–1 m/s, crossing the support takes no more than 10 minutes. Lifting the machine onto a support, towing, and crossing the support can be done by a team of installers consisting of 3–4 people. Thus, it takes only about 3–5 hours to lay a straight section 1 km long.

The construction lengths of the wound fiber optic are connected to each other using hanging welding couplings. The welded joints are secured in a standard welding cassette, then the cassette, together with a reel with a spare cable, is placed in a sealed coupling, which is suspended on the wire using standard fasteners (Fig. 5.13).

The weight of the coupling with cable reserve and organizing plate does not exceed 5 kg. Coupling has a streamlined shape, similar to a disk suspended on a wire parallel to the surface of the earth, in order not to provide much resistance to the wind and not to increase the wind load on the supports. And, in addition, during the operation of the line, all couplings are under high voltage, which excludes unauthorized access to them or vandalism. All metal parts of the coupling in contact with the atmosphere are reliably protected by a weather-resistant coating in accordance with the requirements of the standards. To protect the coupling body from shot penetration, the bottom cover is made of thickened steel.

Despite the fact that only dielectric materials are used in the cable design, short-circuit currents may flow along the surface of the cable sheath. To transfer a fiber-optic cable from a high-voltage wire to grounded support structures, a composite insulator is used at the beginning and end of the winding section, appearance which is shown in Fig. 5.14. Along the longitudinal axis, the composite insulator has a channel for passing a fiber-optic winding cable. At the ends of the insulator there are sealed connectors, with the help of which the cable input and output are reliably protected from atmospheric precipitation entering the insulator channel. The composite insulator is attached to the overhead line wire from above, and from below, using a bracket, to the power line support.

OK winded onto a lightning protection cable is able to withstand any impact environment: ice, wind load, changes

temperatures, as well as short-circuit currents on the line, lightning strikes, vibration, etc. This construction method is used on overhead lines from 35 kV and above (Fig. 5.15).

Rice. 5.15. Rewinding the fiber optic cable to the lightning protection cable

For this type of installation, specialized devices have been developed - winding machines. Their principle of operation is as follows: one mechanism (traction) allows the device to move evenly along the cable, the second mechanism (winding) rotates the drum attached to the machine with the construction length of the cable around the cable. The fiber optic cable is simultaneously unwound from the drum and wound onto the cable. Before passing the next span, special “working ladders” are strengthened on the supports, necessary to prepare the mechanisms for work. The winding machine is lifted onto a support and hung onto the cable by a traction device in the direction of movement. A drum with a cable is installed on the machine. Where it approaches the support, the cable is secured with a special clamp that prevents it from unwinding from the cable. After this, the traction and winding devices are started. The construction length of the cable is wound on the span between two supports. When the winding machine approaches the next support (beyond 5–7 m), the cable is again fixed with a clamp that prevents it from unwinding, after which the machine is dismantled and can be used on the next span. On the support itself, the cable is fixed in both directions with anchor clamps. In this way, a tension pass-through unit is formed - the so-called “jumper”.

Improvements in the design of machines for winding fiber optic cables have made it possible to create a device whose operating principle is similar to a spindle. The weight of such a device is no more than 15 kg, and the payload is up to 180 kg, which makes it possible to wind the OC over spans up to 6 km long (Fig. 5.16).

Rice. 5.16. Winding machine:

a) with a base drum; b) with a cable length equal to the span length; c) cable carrier - the main element

This device was used for the construction of wound fiber optic lines in the territory Russian Federation. To increase the reliability of fiber-optic lines during operation, the following solution was proposed: until the middle of the span, the cable is wound in one direction, and then in the opposite direction. In the middle of the span, the fiber-optic cable is secured with a special clamp, which, in the event of a break in the supporting wire or cable, releases the cable and thereby avoids its breakage.

The advantages of winding technology are undeniable. First of all, this is the ability to build fiber-optic lines in almost any conditions, both rough terrain (mountains, tundra, taiga where power lines are built) and various industrial barriers (iron and car roads, feeder lines for various purposes, houses, gardens, ravines, etc.) without additional accessories and platforms.

Winding an optical cable onto a phase wire virtually eliminates its icing, which, like vibrations on the spans between supports due to wind loads, is the main cause of breakage of overhead wires. This is achieved by heating the moisture-proof polyethylene sheath of the optical cable wrapped around the wire under the influence of the electromagnetic field of the power line. In addition, increased turbulence air flow, flowing around the “Optical cable – power line wire” system reduces the vibration level by 40–60%.

The technology under consideration provides average speed winding OK up to 5–6 km per shift, allows you to pass difficult and inaccessible sections of the route.

The first method is installation using a built-in self-supporting cable.

Here a galvanized steel cable is used, which is stretched on consoles attached to support pillars screws. The cable is attached to it using hangers, which are also made of stainless metal. With this installation method, accurate calculation is important: there are sag standards that affect the maximum installation height of the consoles. So, the lowest point of the cable sag should be no lower than 4.5 meters above the ground. Accordingly, the consoles must be strengthened so as to ensure not only compliance with this parameter, but also taking into account the gap for mounting hangers and the free movement of the cable along the loops of the mounting fittings.

Fig. No. 1. Equipment placement diagram for hanging an optical cable on an overhead power line

Work rules:

The line on which the cable is suspended must be de-energized. Carrying out work while maintaining a connection to the public network is prohibited.
Installation of fiber-optic couplings of any type is allowed while maintaining the network connection to the power supply.
The installer must have a working radio with him when carrying out work.
Lay out cable lines prohibited on land.
The location of the rolling machines on the site should be no closer than three heights from the zero mark to the current position of the rolling roller.
Cable rolling is carried out strictly in the air using a “cable leader”; the ends of the cable and cable are connected with a mounting stocking.
To protect the cable leader and the mounted OK line from twisting, a swivel is used. Balancers must be used at intervals of 4 meters from each other.
For different types of supports, different types of clamps are used (supporting on intermediate ones and tensioning on anchor-corner ones).
To protect against external damage, installation of a protector is mandatory.

Installation of fiber optic lines between houses and buildings.

For these purposes, certain types of cable are used, the characteristics of which are given below.

Fig. No. 2. Photo of OK fastening when pulling between two houses

Characteristics and features of overhead cable lines

OPC is a high temperature resistant fiber optic cable. Can be used in the range from -60 to +70 degrees. Withstands tension up to 12 kN at a pressure of 0.5 kN/cm. Depending on the requirements of the installed communication line, the cable can include from 2 to 48 optical fibers. The filler of the internal cavity is a hydrophobic gel to protect the core from getting wet. A cable of this type can be installed along overhead networks between buildings and existing power lines and supports, including contact networks of railway transport, funiculars, trams, etc., power lines. You can select a cable of this brand in the catalog.

OKPTS is a cable with a central tube, which can contain up to 24 fibers. The external type power element can be a fiberglass rod or steel rope or wire in plastic insulation. This type The cable can also be used at temperatures from -60 to +70 °C. Allowable tension is 4-9 kN. The scope of application and installation procedure do not differ from OPC.

Methods for suspending cables on overhead communication line supports

There are three methods for hanging cables:

Installation inside a lightning protection cable.
Winding onto phase and lightning protection wiring.
Suspension of self-supporting OK on supports.

When installed on existing communication lines, including high voltage supports Power lines and contact networks, the type of cable used must be resistant to electromagnetic fields of any origin. This means a lightning strike, power line surges, and natural turbulence. In addition, the conductor must comply with the permissible elongation (sagging) indicators, and installation must be carried out in compliance with the dimensions of the cable fastening intervals. A cable made of polyamide threads copes with this task. The strength of this carbon fiber is very high, which allows cable suspension to be carried out at large distances between supports.

The optical cable can also be mounted on a separate cable or other external element. If a dielectric wire is not used, it can be replaced by an optical cable built into the lightning protection cable.

With this choice, the conductor is a means of lightning protection and an information transmitter.

At installation of fiber-optic communication lines in tunnels, conductors must have a non-flammable sheath.

It should be noted that in Russian conditions, the requirements for fiber optic cables built into the ground wire differ in a number of features. These features lie primarily in the fact that climatic conditions require an operating temperature range from –60° C to +70° C. This means that the hydrophobic fillers of the modules and cable core must maintain their parameters within the specified range. In addition, the temperature coefficients of expansion of the cable and ground wire elements must be very close to each other.

A lightning protection wire, having one or two layers of ASC and containing an optical core, is mounted on top of the power line and has the dual function of a lightning wire and a communication cable. The process of building such fiber-optic lines is complex technical problem, associated with the use of powerful tensioning mechanisms, and the speed of construction and the technology for replacing an existing cable with a fiber-optic one depend very much on the profile of the power line, i.e., the terrain through which it passes. Under normal conditions, a work crew lays up to 5 km of fiber optic cable per day.

The main advantage of fiber-optic lines implemented using this technology is the high reliability of the communication line, which is due to powerful load-bearing elements of power lines designed for a service life of up to 50 years. It should be noted that during the implementation of the first projects for the construction of fiber-optic lines, OK was used in the lightning protection cable along power lines foreign manufacturers. However, at present, domestic cable of the OPGT type produced by Saranskkabel Optics, Moskabel-Fujikura and other Russian manufacturers is increasingly being used.

The high reliability of fiber-optic lines implemented on the basis of a lightning protection cable is explained by the fact that bearing structures Power lines are designed for a long service life (up to 50 years) and can withstand external destructive loads, even hurricane loads. In addition, mechanical damage to the fiber-optic line, which is located at the height of a 10-story building in a very durable metal shell, is unlikely. This explains their construction in hard-to-reach regions, of which there are plenty in our country.

5.3. Suspension of a self-supporting fiber optic cable on a power line

This method of construction has found the most wide application on departmental networks, such as EZhD, Gazprom, Energosystem and other departments. This is due to the fact that the construction method itself is quite simple, and these companies are the owners various types supports

For the construction of fiber-optic lines by suspension on the supports of high-voltage power lines and railway transport, a dielectric self-supporting cable is used, provided that its load-bearing capacity is sufficient and the location of the cable itself does not interfere with normal maintenance the line on which it is suspended.

This construction method is used mainly where the spans are short. These are electric railway contact networks (Lrun. ≈ 70 m), distributed

power line distribution networks (Lrun – 50÷70 m), overhead line supports (Lrun – 50÷70 m). For the construction of trunk fiber-optic lines, where there are mainly large spans

you, cables with enhanced mechanical characteristics are used, the parameters of which must be determined by calculation based on data on the climatic characteristics of the region where the designed fiber-optic line will be located.

All work on hanging the OK on supports is carried out in accordance with the current rules, regulations and technical conditions laid down in the projects.

The method of hanging a fiber optic cable on a power line is associated with certain difficulties, primarily due to the fact that the power line is constantly energized. Therefore, when hanging a cable, it is necessary to obtain permission from the owners of power lines to carry out work, including disconnecting the voltage. In addition, personnel must be trained and have an appropriate electrical safety group. The most effective in this case is collaboration construction organizations communications and representatives of the energy sector, along whose power transmission line supports the suspension of the fiber optic cable is carried out.

Maintaining construction work suspension OK is carried out at a temperature not lower than –10 °C. Only in exceptional cases is it permissible to carry out work at temperatures below –10 °C, and all precautions must be observed.

During the construction of fiber-optic lines along power lines, they are currently successfully used as Newest technologies design surveys, allowing to examine the line in order to determine the possibility of hanging a fiber optic cable on them, to select a cable suspension route and its design, as well as the latest technological equipment, which allows for construction and installation work to be completed on time and with high quality.

The design and construction of fiber-optic communication lines along power lines is regulated by the following documents.

1. “Rules for suspension and installation of self-supporting fiber-optic cable on the supports of the contact network and high-voltage auto-blocking lines” (approved by the Ministry of Railways of the Russian Federation on August 16, 1999 N TsE/CIS-677). Note: Document text as of January 2011.

2. “Rules for the design, construction and operation of fiber-optic communication lines on overhead power lines

voltage 0.4–35 kV.” SO 153-34.48.519-2002.

Unrolling and hanging of the fiber optic cable on power lines is carried out under tension with preliminary pulling of the leader cable (rope) along the unrolling rollers. Before starting work on rolling out and hanging the FOC, it is necessary to install the necessary mechanisms - a brake and tensioning machine, a mobile installation laboratory, - LIOC, etc.

Rice. 5.5. Tensioning and braking machine for self-supporting fiber optic cable

On all the supports of the power line section where the cables are suspended, cable fastening units are mounted, and unrolling rollers are suspended nearby, along which the dielectric cable leader is pulled. The rollers must correspond to the OK diameter. To suspend a self-supporting OC, rollers of two sizes are widely used: small, with an outer diameter of 200 mm and an inner diameter of 138 mm, and large, with an outer diameter of 676 mm and an inner diameter of 604 mm.

Rice. 5.6. LIOC mobile laboratory

Unrolling rollers must have a low coefficient of friction and be designed for easy installation. They must also provide reliable protection optical cable from jamming in the body of the roller and protection from braking of the roller in the event of contact with its fastening elements (Fig. 5.7).

Rice. 5.7. Installation of a self-supporting fiber optic cable

A special dielectric rope with high strength, low elongation coefficient and low torsion coefficient is used as a leader cable used to suspend the OK. The standard length of the cable leader is 1 or 0.5 km, which allows using special connectors to complete it in accordance with the construction lengths of the cable. In this case, the length of the leader cable should be one standard length exceed construction length FOC.

The leader cable is unwound from the winch drum and passed through the grooves of each roller at each support. The leader cable is pulled to the brake machine, passed through it and connected through a swivel and cable stocking to the end of the fiber optic cable on the drum mounted on the lifting brake device.

Pulling the leader cable with the FOC attached to it is done with a winch by winding the leader cable onto the winch drum. In this case, in the process of pulling the cable, visual control behind the sag and the absence of twisting of the fiber optic along the route.

The pulling speed is on average about 1.8 km/h. When approaching, while pulling the joint of the leader cable and the fiber optic cable to the unrolling roller, the pulling speed is reduced to a minimum. Rolling ends when the OK passes through the rolling roller on the end support to a distance equal to the height of the roller suspension, plus 15–20 m.

	After rolling out on the support, approx.
	which the drum with OK is located,
	the cable is secured using
	tension clamp (Fig. 5.8). By way of
	cable tension is set to a certain
	project, the sag boom is OK in the sag
	tah, and the cable is attached to another grap-
	vertical support of the mounted area
	using a tension clamp.
Rice. 5.8. Application	The brake machine is adjustable
tension clamp	braking force to ensure
	constant effort ensuring

sag arrow. The OK sag should not go beyond a five percent tolerance, more or less than the design specification.

After securing the OK to the end supports, it is removed from the rollers and secured in supporting clamps.

Work on fixing the fiber optic cable in the designed position is carried out no later than 48 hours after its rolling out. During this work the following is performed:

fastening the FOC to the supports with tension clamps;

transferring the FOC from the rollers to the supporting clamps;

laying and securing technological stocks of OK lengths on supports. Examples of OK fastening depending on the type of supports and design

fittings are shown in Fig. 5.9.

Rice. 5.9. Clamps for fastening FOC

The lowering of the OC from the overhead line supports is carried out in order to ensure the welding of optical fibers and optical measurements of the cable without lifting the welding and measuring equipment. Descents are carried out with the same cable that is mounted on the overhead line. The descent cable is attached to the support body using special designs with clamps, the height of the coupling itself must be at least 5.0 m from the ground.

The installation of couplings is carried out similarly to the installation of fiber optic cables laid in the ground in specially equipped vehicles (Fig. 5.6). The mounted couplings and the technological reserve length of the FOC are placed in protective containers attached to the support body at a distance of at least 6 m from the ground level. During descent, a dielectric suspended fiber optic cable, introduced into the premises of a communication facility or a transition to an underground fiber optic cable, is inserted into a protective plastic (metal) pipe fixed to the body of the support with the ends of the pipe with the cable sealed using a heat-shrinkable tube.

Optical cables for suspension along power lines are manufactured by a number of Russian factories. CJSC “People's Firm Elektropovod” (Moscow) has extensive experience in the production of self-supporting fiber optic cables for suspension along power lines, one of the first in Russia to start producing fiber optic cables. Self-supporting dielectric cables manufactured by ZAO Samara Optical Cable Company (Samara) and Transvok (Borovsk, Russia) have proven themselves well. Kaluga region) .

Typical design A self-supporting FOC is a modular twisted core protected by aramid threads, which are used as reinforcing elements (Fig. 5.10). In this case, the OM is located inside tubes (modules) made of durable polybutylene terephthalate or polyamide, which are filled with a water-repellent gel. Various companies usually use 5- or 6-element twisting on a central element made in the form of a fiberglass rod. A polyethylene sheath such as HDPE or LDPE is placed on top of the twisted modules, depending on the required crush resistance. Aramid threads are applied to the intermediate shell, which are laid, as a rule, in two layers of opposite layers.

Rice. 5.10. Main types of self-supporting fiber optics:

a) cable with fiberglass bundles; b) cable with aramid threads

The durable outer shell protects the fiber optic cable from external influences.

Shell options with increased resistance to electrical breakdown and aggressive environments are available.

Moscow State University

Ways of communication (miit)

Department of Automation and Telemechanics

on railway transport."

Course work

By discipline:

"Fiber-optical transmission systems."

"Calculation mechanical strength fully

Dielectric self-supporting

Fiber optic cable."

Completed by: student of group TUS-361 Osipov S.E.

Volkova E.S.

Moscow – 2017

1. Description of the cable design A-D(T)2Y.

2. Description of the work performed when hanging a self-supporting fiber optic cable on overhead contact line supports.

3. Mechanical calculation of a self-supporting fiber optic cable.

3.1.Calculation of specific load from own strength cable gravity.

3.2.Calculation of the specific load from the effects of ice during icy conditions.

3.3.Calculation of the specific load due to the cable’s own gravity and the gravity of the ice.

3.4.Calculation of the specific load from wind pressure on the cable (in the absence of ice).

3.5. Calculation of the specific load from the influence of wind on a cable covered with ice.

3.6. Calculation of the specific load from the gravity of the cable, the ice covering it and the influence of wind.

4. Determination of the critical span length.

5.Calculation of boom sag.

Description of the CORNING ADSS A-D(T)2Y cable design.

The figure shows the design of the Corning ADSS A-D(T)2Y cable (dielectric self-supporting fiber optic cable)

1. Dielectric multi-fiber core tube (D)

2. Concentric element carrying tensile load (aramid) (2Y).

3. Polyethylene sheath (T)

Special characteristics include:

Installation without power outage;

Long span lengths;

Light weight;

Small outside diameter

Operating temperature from -40 to +40ºС

Description of the work performed when hanging a self-supporting fiber optic cable on overhead contact line supports.

Work on the suspension and installation of a fiber optic cable can only begin if there is a customer-approved detailed design for the construction of a fiber optic link, albums of typical components and parts, and permission from the railway power supply service to carry out work in the area of the contact network and the high-voltage automatic blocking line.

To develop the project, the customer transfers the initial data to the design organization as part of the task for designing a fiber-optic line.

Before the beginning installation work for suspension FOC must be performed following works:

project documentation was studied;

a full-scale examination of the FOC suspension route and support structures was carried out;

the order and timing of replacement of supports, the timing of installation of new and additional supports have been established;

supports with insufficient bearing capacity and new and additional supports were installed in accordance with the design of the lines, as well as guy wires on the supports required by the project;

the anchor sections were clarified and the most rational sequence and direction of installation of the anchor sections were established;

If necessary, trees and bushes were cut down;

railcars, motor carriages, carriages for workers performing work on the suspension of fiber optic cables, mechanisms for loading and unloading cable products, equipment and space for welding work and installation of couplings have been prepared;

supplies, materials, equipment, tools, radio stations and power supplies were prepared and checked;

the procedure and time for delivery of workers, equipment and tools to the place of work are determined;

the procedure for providing “windows” has been determined.

When hanging and installing a fiber optic cable, “windows” of at least 3 to 4 hours must be provided in accordance with the procedure approved by the head of the railway.

“Windows” for hanging and mounting the FOC should be provided, as a rule, during daylight hours. In areas where “windows” in the train schedule are provided for at night, the manager is obliged to ensure the place where work is carried out in accordance with established standards.

When pulling a fiber optic cable, the following work is performed:

pulling a dielectric cable leader;

FOC broach.

Work on stretching the fiber optic cable can be carried out “from the track” with the voltage removed and the stage taken, or if there are approaches to the track and electrical safety is ensured, “from the field” without voltage removal.

A leader cable is pulled along rollers pre-hung on the brackets. To do this, after engaging in the hauling complex and relieving tension, one cargo trailer with leader cable reels is installed at the beginning of the anchor section 25 - 30 m from the anchor support, and the second trailer, coupled with the railcar, begins to slowly move towards the first anchor support. Opposite the first anchor support, the railcar stops, the mounting cradle with two assemblers rises to the bracket with the roller. The leader cable is detached from the cradle, passed through the roller and reattached to the cradle. In this position, the railcar slowly moves to the next support. At the next support, the leader cable is again passed through the roller and the movement of the railcar resumes. In this way, the leader cable is stretched throughout the entire section. After passing the leader cable through the roller of the outermost anchor support, the railcar with the trailer with cable drums located in front of it moves a distance of 25 - 30 m beyond the last support and stops. While pulling the leader cable, the fitters operating the traction and braking device with reels slow down the coils, ensuring that the leader cable rolls out under tension.

In the extreme position, the leader cable is connected through a device that prevents the FOC from twisting, using a “stocking” cable clamp, to the FOC located in the drum on the cargo trailer. The railcar is uncoupled from the trailer with the cable drum and returns to the first trailer with the reels free from the cable leader. The motors of the traction module are turned on from the railcar using a hydraulic drive and the slow pulling of the fiber optic cable begins. In this case, the drum from which the fiber optic is rolled out is slowed down so that the required sag of the fiber optic in the spans is ensured.