Selection of racks of contact network supports. Selection of parts and materials for contact network nodes Select mounting devices, protective equipment, signal accessories and tools, check their serviceability and test periods. Submerge them, as well as

A complex of devices for the transmission of electricity from traction substations to EPS through current collectors. The contact network is part of the traction network and for rail electrified transport it usually serves as its phase (with alternating current) or pole (with direct current); the other phase (or pole) is the rail network.
The contact network can be made with a contact rail or contact suspension. Running rails were first used to transmit electricity to a moving vehicle in 1876 by the Russian engineer F. A. Pirotsky. The first contact suspension appeared in 1881 in Germany.
The main elements of a contact network with a contact suspension (often called air) are the wires of the contact network (contact wire, carrier cable, reinforcing wire, etc.), supports, supporting devices (cantilevers, flexible crossbars and rigid crossbars) and insulators. Contact networks with contact suspensions are classified: according to the type of electrified transport for which the contact network is intended, - main, including high-speed, railway, tram and quarry transport, mine underground transport, etc .; by the nature of the current and the rated voltage of the EPS powered by the contact network; on the placement of the contact suspension relative to the axis of the rail track - for the central (main railway transport) or lateral (industrial transport) current collection; by type of contact suspension - contact networks with a simple, chain or special suspension; according to the features of implementation - contact networks of hauls, stations, for arts, structures.
Unlike other power supply devices, the contact network does not have a reserve. Therefore, increased requirements are imposed on the reliability of the contact network, taking into account which design, construction and installation, maintenance of the contact network and repair of the contact network are carried out.
The choice of the total cross-sectional area of ​​\u200b\u200bthe wires of the contact network is usually carried out when designing a traction power supply system. All other issues are solved with the help of the contact network theory, an independent scientific discipline, the formation of which was largely facilitated by the work of owls. scientist I. I. Vlasov. Based on the design issues of the contact network are: the choice of the number and brands of its wires in accordance with the results of calculations of the traction power supply system, as well as traction calculations, the choice of the type of contact suspension in accordance with the max, speeds of the ERS and other current collection conditions; determination of the span length (mainly according to the condition of ensuring its wind resistance); selection of types of supports and supporting devices for hauls and stations; development of contact network designs in arts, structures; placement of supports and drawing up plans for the contact network of stations and spans with the coordination of zigzags of wires and taking into account the implementation of air arrows and sectioning elements of the contact network (insulating interfaces of anchor sections, sectional insulators and disconnectors). When choosing methods of construction and installation of a contact network in the course of electrification of railways, they strive to have them as little as possible reflected in the transportation process, while unconditionally ensuring the high quality of work.
The main industries, enterprises for the construction of a contact network are construction and installation trains and electrical installation trains. The organization and methods of maintenance and repair of the contact network are selected from the conditions of ensuring a given high level of reliability of the contact network at the lowest labor and material costs, the safety of workers in the areas of the contact network, and possibly less impact on the organization of train traffic. Production, acceptance for the operation of the contact network is the distance of the power supply.
The main dimensions (see fig.), characterizing the placement of the contact network relative to other posts, devices. e., - height H of suspension of the contact wire above the level of the top of the rail head;


The main elements of the contact network and the dimensions characterizing its placement relative to other permanent devices of the main railways: Pks - wires of the contact network; O - support of the contact network; And insulators.
distance A from live parts to grounded parts of structures and rolling stock; distance G from the axis of the extreme path to the inner edge of the contact network supports at the level of the rail heads.
Improving the design of the contact network is aimed at increasing its reliability while reducing the cost of construction and operation. J.-b. contact network supports and foundations of metal supports are made taking into account the electrocorrosive effect of stray currents on their fittings. An increase in the service life of the contact wire is achieved, as a rule, by using carbon contact inserts on current collectors.
During the maintenance of the contact network on domestic railways. e. without stress relief, insulating removable towers, mounting railcars are used. The list of works performed under voltage was expanded due to the use of double insulation on flexible crossbars, in wire anchors and other elements of the contact network. Many control operations are carried out by means of their diagnostics, which are equipped with laboratory cars. The efficiency of switching sectional disconnectors of the contact network has increased significantly due to the use of telecontrol. The equipping of power supply distances with specialized mechanisms and machines for repairing the contact network (for example, for digging pits and installing supports) is increasing.
An increase in the reliability of contact networks is facilitated by the use of ice melting methods developed in our country, including without interrupting train traffic, electrorepellent protection, wind-resistant diamond-shaped contact suspension, etc. To determine the number of areas of contact networks and the boundaries of service areas, they use the concepts of operational length and deployed the length of electrified tracks, equal to the sum of the lengths of all anchor sections of contact networks within the specified limits. On domestic railways, the developed length of electrified tracks is an accounting indicator for districts of electricity supply, distances of electricity supply, and road sections, and exceeds the operational length by more than 2.5 times. The determination of the need for materials for the repair and maintenance needs of contact networks is carried out according to its expanded length.

A contact network is a special power line that serves to supply electrical energy to an electric rolling stock. Its specific feature is that it should provide current collection to moving electric locomotives. The second specific feature of the contact network is that it cannot have a reserve. This leads to increased requirements for the reliability of its operation.
The contact network consists of a contact suspension of the track, supports of the contact network, supporting and fixing devices in the space of the wires of the contact network. In turn, the contact suspension is formed by a system of wires - a carrier cable and contact wires. For a DC traction system, there are usually two contact wires in the suspension and one for an AC traction system. On fig. 6 shows a general view of the contact network.

The traction substation supplies electricity to the rolling stock through a contact network. Depending on the connection of the contact network with traction substations and between contact suspensions of other tracks of a multi-track section, the following schemes are distinguished within the boundaries of a separate inter-substation zone: a) separate two-way;

Rice. 1. General view of the contact network

b) nodal; c) parallel.


a)

v)
Rice. Fig. 2. Main power supply schemes for catenary rails a) – separate; b) - nodal; c) is parallel. PPS - points of parallel connection of contact suspensions of various ways; PS - sectioning post; TP - traction substation

Separate two-way circuit - contact suspension power supply scheme, in which energy is supplied to the contact network from two sides, (adjacent traction substations operate in parallel to the traction network), however, contact suspensions are not electrically connected to each other within the boundaries of the inter-substation zone. The scope of such a scheme is the supply of electric railway sections with non-extended inter-substation zones and relatively uniform power consumption in directions.
Nodal scheme - a scheme that differs from the previous one by the presence of an electrical connection between the track suspensions. Such communication is carried out using the so-called sectioning posts of the contact network. The technical equipment of the sectioning posts of the contact network allows, if necessary, to eliminate not only the transverse connection between the track suspensions, but also the longitudinal one, breaking the contact network within the boundaries of the inter-substation zone into separate electrically unconnected sections. This significantly increases the reliability of the traction power supply system. On the other hand, the presence of a node in normal modes allows more efficient use of contact networks for the transmission of electrical energy to the electric rolling stock, which provides significant energy savings in case of uneven power consumption in directions. Consequently, the scope of such a suspension is sections of an electric railway with extended inter-substation zones and significant uneven power consumption in directions.
Parallel circuit - a circuit that differs from the nodal circuit by a large number of electrical nodes between the catenary rails. It is used for even greater uneven consumption of electricity along the tracks. This scheme is especially effective when driving heavy trains.

L - estimated span length, equal to half the sum of the lengths of spans adjacent to the calculated support, m;

C f \u003d 200 N - load from the weight of half of the fixation assembly.

Horizontal load on the support under the action of wind on the wires:

where H i j - wire tension, N/m;

R - curve radius, m.

Load on the support from a change in the direction of the wire when it is withdrawn to the anchorage

where a is a zigzag on a straight section of the path, m.

Total bending moment relative to the heel of the console

(6.8)

Let's calculate the loads on the intermediate support on the straight section

Gkpod \u003d 29.93 * 70 + 150 + 200 \u003d 2445

Gcons \u003d 24 * 9.8 \u003d 235.2

Load from the bracket on the field side, N/m

Gpdpr \u003d 1.72 * 70 \u003d 120.8

Rdpr \u003d 5.52 * 70 \u003d 387.06

Horizontal load on the support under the action of wind on the wires of the CS

PNT=6.72*70=470.8

Pkp \u003d 8.39 * 70 \u003d 587.3

Surface area affected by the wind

Sop=(9.6*(0.3+0.4))/2=3.36

Pop=0.615*0.7*25 2 *3.36=904.05

Let's calculate the moments

M og \u003d 9.27 * 387.05-120.8 * 0.6-401.8 * 0.5 + 235.2 * 1.8 + 9 * 470.8 + 2 * 7 * 587.3 + + 0.5*904.05*9.6+3.3*2445.2=28607.6 Nm

M op \u003d (9.27-6.75) * 387.05-120.8 * 0.6-401.8 * 0.5 + 235.2 * 1.8 + (9-6.75) * 470.8 +2*(7-6.75)*587.3+0.5*904.05*(9.6-6.75)+3.3*2445.2=8672.1 Nm

Table 6.1

In ice mode with wind, the moment is greatest. According to this moment, we select the support, provided that it should be less than the standard moment. We choose a support SS 136.6-2 with a standard moment = 59000 N. Calculations for the remaining supports are made on a computer.

CONCLUSION

In the course of work on the design of the contact network of a given section, the loads on the wires of the contact network were calculated (for the main track gk = 8.73 N/m; gn = 10.47 N/m; g = 29.9 N/m) for the given climatic, wind and ice regions, the results are summarized in table 1.1. Based on the calculated loads, the permissible span lengths were determined (Table 2.1), plans for the contact network of the station and the span were developed. We completed the plan of the station contact network: we prepared the plan of the station, outlined the places for fixing the contact wires, placed supports in the middle of the station and at its ends, placed zigzags, traced anchor sections at the station, power lines, selected supporting and supporting structures. We also completed the plan for the contact network of the haul: we prepared a plan for the haul, completed the breakdown of supports and anchor sections, placed zigzags, and made a choice of types of supports. Completed the processing of plans for the contact network and compiled the necessary specifications.

Based on the calculated loads and span lengths on the stage, a mechanical calculation of the 1st track of section "a" was made. With its help, the design mode was determined - the mode of ice with wind, i.e. the greatest tension of the carrier cable occurs at a temperature of -5 for this area. Using the calculation, assembly curves were built for the construction of a contact network. After that, the loads from the wires and the wind loads on the support were calculated in three modes. According to the largest bending moment, the support SS 136.6-2 with a standard bending moment of 59000 N was chosen.

It was proved that at the station, when passing the contact suspension under the footbridge, the best way was to pass under the ASSO without fastening to it.

During the design, most of the calculations were carried out on a computer, which reduced the time of calculations and made them more accurate.

We are designing in order to increase the throughput and change diesel traction to electric, which is much cheaper.

LITERATURE

1. A.V. Efimov, A.G. Galkin, E.A. Polygalova, A.A. Kovalev. Contact networks and power lines. - Yekaterinburg: UrGUPS, 2009. - 88s.

2. Markvart K. G. Contact network. M: Transport, - 1977. - 271s.

3. Freifeld A. V., Brod G. N. Design of a contact network.
M .: Transport, - 1991. - 335s.

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console pin suspension network

Introduction

1. Theoretical section

1.1 Calculation of loads acting on catenary

1.2 Calculation of the maximum allowable span lengths

1.4 Tracing the contact network of the stage

2. Technology section

2.1 Maintenance of consoles

3. Economic section

4.1 Organizational and technical measures to ensure the safety of workers. Working conditions in the area of ​​the contact network

Conclusion

Bibliographic list

Introduction

The contact network is the most important element of the traction power supply system for electric transport. The successful performance of the main function of railway transport, which is the timely transportation of passengers and goods in accordance with a given traffic schedule, largely depends on the reliable operation of the contact network.

The main task of the contact network is the transmission of electricity to the rolling stock due to reliable, economical and environmentally friendly current collection in design weather conditions at the established speeds, types of pantographs and values ​​of the transmitted current.

The main elements of a contact network with a contact suspension are the wires of the contact network (contact wire, carrying cable, reinforcing wire, etc.), supports, supporting devices (consoles, flexible crossbars and rigid crossbars) and insulators.

When designing a contact network, the number and brand of wires are selected based on the results of calculations of the traction power supply system, as well as traction calculations; determine the type of contact suspension in accordance with the maximum speeds of the electric rolling stock and other current collection conditions; find the span lengths; choose the length of the anchor sections, types of supports and supporting devices for hauls; develop the design of the contact network in artificial structures; they place supports and draw up plans for the contact network at stations and spans with the coordination of wire zigzags and taking into account the implementation of air arrows and sectioning elements of the contact network (insulating interfaces of anchor sections and neutral inserts, sectional insulators and disconnectors).

In recent years, the movement of heavy and long trains has been expanding on the roads of the country, a new high-capacity electric rolling stock has been put into operation, the speeds of passenger and freight trains have increased, and freight traffic is growing.

This thesis project considers the design of a direct current contact network in order to gain skills in designing, choosing equipment, building installation curves and checking the condition, adjusting and repairing a sectional insulator.

1. Theoretical section

1.1 Calculation of loads acting on the suspension

From the whole variety of combinations of meteorological conditions acting on the contact network wires, three design modes can be distinguished in which the forces (tension) in the carrier cable can be the greatest, dangerous for the strength of the cable:

Minimum temperature mode - cable compression;

Maximum wind mode - cable stretching;

Ice mode - cable stretching.

For these design modes and determine the load on the carrier cable.

1.1.1 Minimum temperature mode

The carrying cable experiences only the vertical load of its own weight and from the weight of the contact wire, strings and clamps.

The vertical load from the own weight of the 1st running meter of wires in daN/m is determined by the formula:

where gt, gk - load from the own weight of one meter of the carrier and contact wires, daN / m; should be taken and

n is the number of contact wires;

gc - load from the own weight of the strings and clips evenly

distributed along the length of the span is assumed to be 0.05 daN/m for each wire.

The main ways of the station and the haul:

1.1.2 Maximum wind mode

In this mode, the carrier cable is subjected to a vertical load from the weight of the contact suspension wires and a horizontal load from wind pressure on the carrier and contact wires (there is no ice). The wind of maximum intensity is observed at an air temperature of +. The vertical load from the weight of the catenary wires is defined above by formula (1.1).

The horizontal wind load on the carrier cable is determined by the formula:

where Cx - aerodynamic drag coefficient of the wire to the wind is determined according to the table p.105;

The coefficient taking into account the influence of local conditions, the location of the suspension on the wind speed, is determined according to table 19 p.104;

Normative wind speed of the greatest intensity, m/s; repeatability 1 time in 10 years is determined according to table 18 p.102;

d - diameter of the carrier cable, mm; p.33.

The horizontal wind load on the contact wire is determined by the formula:

where H is the height of the contact wire p.26.

Excavation up to 7 m deep:

Embankment with a height of more than 5 m:

The resulting (total) load on the support cable in daN/m is determined by the formula:

Excavation up to 7 m deep:

Straight section, curves of various radii:

Embankment with a height of more than 5 m:

When determining the resulting load on the contact wire, it will not be taken into account, because. mostly perceived by fixators.

1.1.3 Ice with wind

In this mode, the catenary wires are subjected to a vertical load from their own weight, the weight of ice and the horizontal load from wind pressure on the wires of the catenary, the wind speed in ice minus C, the vertical load from the dead weight of the catenary wires is defined above.

The vertical load from the weight of ice on the carrier cable daN/m is determined by the formula:

where - the overload factor can be taken: = 0.75 - for protected sections of the contact network (recess); 1 - for normal conditions of the contact network (station, curve); = 1.25 - for unprotected sections of the contact network (embankment);

Ice wall thickness on the carrier cable, mm

d - diameter of the carrier cable, mm; - 3.14.

The thickness of the ice wall on the carrier cable, mm, is determined by the formula:

where is the normative ice wall thickness, mm;

Coefficient taking into account the influence of the wire diameter on the deposition of ice p. 100 ;

Coefficient taking into account the influence of the height of the catenary suspension p. 100 .

For the main tracks of the station and the haul for the supporting cable M-95, we accept = 0.98.

For excavation with a depth of more than 5 m = 0.6.

For a straight section of the haul and curves of various radii = 0.8.

For an embankment over 5m = 1.1.

The vertical load from the weight of ice on the contact wire in daN/m is determined by the formula:

where is the thickness of the ice wall on the contact wire, mm; on the contact wire, the thickness of the ice wall is taken equal to 50% of the thickness of the ice on the carrier cable;

Average diameter of contact wire, mm

where H and A are the height and width of the cross section of the contact wire, respectively, mm.

Straight section and curves of various radii:

Excavation up to 7m deep:

Embankment with a height of more than 5m:

Straight section and curves of various radii:

Excavation up to 7 m deep:

Embankment with a height of more than 5 m:

The total vertical load from the weight of ice on catenary wires in daN/m is determined by the formula:

where is a uniform vertical load distributed along the length of the span from the weight of ice on strings and clamps with one contact wire, daN/m, which, depending on the thickness of the ice wall, is

Straight section of the haul and curves of various radii:

Excavation up to 7m deep:

Embankment with a height of more than 5m:

The horizontal wind load on the supporting cable covered with ice in daN/m is determined by the formula:

where is the standard wind speed with ice, m/s. = 13 m/s.

Excavation up to 7m deep:

Embankment with a height of more than 5m:

The horizontal wind load on a contact wire covered with ice in daN/m is determined by the formula:

Straight section and curves of various radii:

Excavation up to 7m deep:

Embankment with a height of more than 5m:

The resulting (total) load on the support cable in daN/m is determined by the formula:

Straight section and curves of various radii:

Excavation up to 7m deep:

Embankment with a height of more than 5m:

1.1.4 Selecting the initial design mode

The results of calculating the loads acting on the wires of the contact suspension are summarized in Table 1.1; Comparing the loads of different modes (mode of minimum temperatures, maximum wind and wind with ice), we determine the mode for subsequent calculations.

Table 1.1

Loads acting on catenary, in daN

terrain

Loads acting on contact suspension

p.u. (curve)

As a result of the calculations, it was found that the resulting load in the maximum wind mode is greater than the load in the wind with ice, based on this, we accept the design mode - wind.

1.2 Determination of span lengths on straight and curved track sections

Rules for the device and technical operation of the contact network of electrified railways (TsE-868). It is recommended to carry out span lengths according to the condition of current collection no more than 70 m.

The span length for a straight section of the track is determined by the formula:

On curves:

Finally, we determine the span length, taking into account the specific equivalent load according to the formulas:

On curves:

where K is the nominal tension of the contact wires, daN;

Maximum allowable horizontal deviation

contact wires; from the axis of the pantograph in the span; - on straight lines and - on curves;

a - zigzag of the contact wire, - on straight lines and - on curves;

The elastic deflection of the support, m, is taken from the table at the corresponding wind speed;

where h is the design height of the suspension;

g 0 - load on the carrier cable from the weight of all wires of the chain suspension;

T 0 - the tension of the carrier cable with a weightless position of the contact wire.

The specific equivalent load, taking into account the interaction of the carrier cable and the contact wire with their wind deflection, daN / m, is determined by the formula:

where T is the tension of the contact suspension carrier cable in the design mode, daN;

The length of the suspension garland of insulators, m, the length of the garland of insulators can be taken: 0.16 m (length of the earring and saddle) with insulated consoles; 0.56 m with two suspension insulators in a garland, 0.73 m with three, 0.90 m with four insulators;

Span length, m

Finally, we determine the span length, taking into account the specific equivalent load:

Straight stretch:

Excavation up to 7m deep:

Embankment with a height of more than 5m:

Curve with a radius of 1300 m:

We take the span length equal to 45m.

Curve with a radius of 2000 m:

Further calculations will be summarized in Table 1.2.

Table 1.2

Span lengths on straight and curved track sections

1.3 Development and justification of the power supply scheme and sectioning of the contact network of the station and adjacent hauls

1.3.1 Drawing up a power supply and sectioning of the contact network

The contact network of the electrified section is divided into separate sections, electrically independent of each other, to ensure reliable operation and ease of maintenance. Sectioning is carried out by insulating mates of anchor sections, sectional insulators, sectional disconnectors, mortise sectionalizing insulators.

Longitudinal sectioning provides for the separation of the contact network of the station from the contact network of hauls along each main track.

Longitudinal sectioning is carried out by four-span and three-span insulating mates, which are located between the input signal and the extreme turnout.

On the insulating mates, longitudinal sectional disconnectors that shunt them are installed, indicated by the capital letters of the Russian alphabet: A, B, C, D.

Transverse sectioning between the tracks is carried out by sectional insulators, transverse disconnectors and mortise insulators in the fixing cables of the transverse and in the non-working branches of contact suspensions. Transverse disconnectors connecting contact suspensions of different sections of stations are designated by the letter "P".

The connection of contact suspensions of tracks, where work is carried out near the contact network, is performed by sectional disconnectors with grounding knives; denoted by the letter "Z".

Modern requirements provide for the use of remote and remote control of sectional disconnectors, therefore linear, longitudinal and transverse disconnectors should be designed with motor drives.

The power supply of the contact network from the traction substation is carried out by supply lines (feeders), usually overhead. They feed on feeders: even paths F2, F4; odd F1, F3, F5.

On double-track sections of direct current, the power supply of the line extending from the traction substation to the contact network of hauls is designed separately for each track. The feeder line feeding the station tracks is allocated separately. In the supply lines of the direct current contact network, linear disconnectors are arranged at the points of their connection to the contact network.

Power line disconnectors are designated "Ф" with digital indices.

The power supply circuit of the station sectioning is shown in Figure 1.1.

Figure 1.1 Scheme of power supply and sectioning of the contact network of the station

1.4 Tracing of the contact network of the haul

tracing contact networks haul

Plans for the contact network of the haul are drawn on a scale of 1: 2000 on graph paper. The required length of the sheet is determined based on the given length of the stage, taking into account the scale and the necessary margin on the right side of the drawing for the placement of general data and the title block.

The plan of the contact network of the stage is drawn in the following sequence:

Preliminary breakdown of the haul into anchor sections. The arrangement of supports on the stage begins with the transfer to the plan of the stage of the supports of the insulating interface. The location of these supports on the haul plan should be linked to their location on the station plan. Linkage is carried out according to the input signal, which is also indicated on the station plan;

Basting of the anchor sections of the contact network, the approximate location of their junctions. In the middle of the anchor sections, the places of medium anchorings are marked, where it is subsequently necessary to reduce the length of the spans.

When planning the anchor sections of the suspension, it is necessary to proceed from the following considerations:

The number of anchor sections on the stage should be minimal;

The maximum length of the anchor section of the contact wire on a straight line is assumed to be no more than 1600m;

Next, the arrangement of supports on the stage. The arrangement of supports is made by spans, if possible, equal to those allowed for the corresponding area of ​​the terrain, obtained as a result of calculating the span lengths. Spans with medium anchorings must be shortened when compensated: two spans by 5% of the maximum design length for the relevant terrain;

Processing of the flight plan. Having completed the arrangement of supports and zigzags of the contact wire, the final breakdown of the contact network of the haul into anchor sections is made and their mates are drawn.

Figure 1.2 shows the catenary passage in artificial structures.

Figure 1.2 Catenary passage in artificial structures

1.5 Selection of support structures

The selection of typical supporting and fixing devices is performed when designing a contact network by linking the developed structures to the specific conditions of their installation.

The project used uninsulated channel brackets No. 5 (NR-II-5). Channel consoles are marked HP (non-insulated with extended rod) and NS (non-insulated with compressed rod).

The selection of consoles in various installation conditions is carried out in accordance with the tables developed in Transelectroproject for areas with a standard ice wall thickness of up to 20 mm inclusive and with wind speeds of up to 35 m/s with a recurrence of climatic loads at least once every 10 years.

The selection of typical non-insulated and insulated consoles for AC and DC lines is performed depending on the type of supports and their installation location. In addition, for direct current lines on straight sections of the track, it is necessary to take into account the dimension of the installation of anchor supports.

Typical brackets are designed metal and wood. Wires of DPR lines are suspended on metal, reinforcing, supplying, suction and reverse current wires (in areas with suction transformers). Wires of overhead lines 6 and 10 kV with voltage up to 1000 V and wave guides are fixed on wooden brackets.

Attachments and racks are used in cases where the height of the supports is insufficient to install the required bracket, and also if it is required to place wires above a rigid crossbar.

Extensions and racks are selected depending on the purpose, if necessary, they are checked for specific loads.

Rigid typical beam-type crossbeams are through trusses of rectangular section, consisting of separate blocks. Diagonal grating: directed in vertical planes and non-directional in horizontal. Crossbars in the usual design, intended for areas with design temperatures up to -40C, are made of VSt3ps6 steel of the 1st and 2nd strength groups. The crossbars are completed from two, three or four blocks, depending on the length of the calculated span. The joints of the blocks of crossbars in the usual version are welded, in the northern version they are bolted. Marking of blocks of crossbars in the usual version - BK (extreme), BS (middle), in the northern version - BKS, BSS. The serial number of the block is added to the letter designation through the dash, for example, BKS-29.

Typical articulated clamps developed at Transelectroproject are selected depending on the type of consoles and their installation location, and for transitional supports, taking into account the location of the working and anchored branches of the suspension relative to the support. In addition, take into account which of them the latch is intended for.

In the designations of typical clamps, the letters F (retainer), P (direct), O (reverse) are used. The marking contains Roman numerals I, II, etc., characterizing the lengths of the main fixators. In the project, fixators of the FO-II, FP-III brands were used in the straight section of the haul and embankment, FP-IV and FO-V in the curved sections of the haul, in the excavation.

Contact network supports can be divided into two main groups: carriers, on which there are any supporting devices (consoles, brackets, rigid or flexible crossbars), and fixing ones, on which there are only fixing devices (clamps or fixing crossbars). In the first case, the supports perceive both vertical and horizontal loads, in the second - only horizontal ones.

Depending on the type of supporting device, there are cantilever bearing supports (with single-track or double-track consoles), rigid crossbar racks (single and twin) and flexible crossbar supports. Cantilever supports are usually divided into intermediate (one contact suspension is attached to them) and transitional, installed at the mates of the anchor sections and air arrows (two contact suspensions are attached to them).

In addition to loads in a plane perpendicular to the axis of the track, the supports can absorb forces from the anchoring of certain wires that create loads in a plane parallel to the axis of the track. In this case, the supports are called anchor. As a rule, contact network supports perform several functions at the same time, for example, a transitional cantilever support can be an anchor and, in addition, also support power wires.

For installation on newly electrified lines, CO-type supports are designed for DC sections. The supports fixed on the foundation were used - separate, which, when connected to the foundation of the TS type, become one-piece. Reinforced concrete supports - СС108.6-1, anchor - СС108.7-3, transitional - СС108.6-2. Supporting slabs of brand OP-2 were used in the project; Anchors type TA-1 and TA-3.

2 . Technological chapter

2.1 Maintenance of consoles

The console of the contact network support is a supporting device fixed on the support, consisting of a bracket in the rod. Depending on the number of overlapping tracks of the console, the support of the contact network can be one-, two- and multi-track. On domestic railways, single-track contact network support consoles are most often used, because with a larger number of contact network support consoles, the mechanical connection between contact suspensions of different tracks reduces the reliability of the contact network. Single-track consoles of the contact network support are used, uninsulated, or grounded, when the insulators are located between the carrier cable and the bracket, as well as in the latch rod, and insulated, with insulators placed in the brackets and rods. Uninsulated consoles of the contact network support (Figure 2. 1) can be curved, inclined and horizontal in shape.

Fig.2 1 Uninsulated console: 1 - carrying cable; 2 -- console thrust; 3 -- console bracket; 4 -- fixative insulator; 5 - latch; 6 carrier cable insulators

Previously, curved consoles of the contact network support were widely used. Inclined consoles of the contact network support are much lighter than curved ones and are more convenient to manufacture and transport. Brackets of inclined consoles of the contact network support are made from two channels or from pipes. The latches are attached to the console brackets through insulators. For supports installed with an increased dimension (5.7 m from the axis of the track), consoles with a strut are used. At the junctions of the anchor sections, when mounting two consoles on one support, the support of the contact network uses a special traverse. The horizontal consoles of the contact network support are used in cases where the height of the supports is sufficient to secure the traction.

With insulated consoles of the contact network support, it is possible to carry out work on the carrier cable near the consoles of the contact network support without disconnecting the voltage, which is unacceptable with non-isolated consoles of the contact network support. Isolated consoles are only inclined, with brackets, which include rod porcelain (console) insulators, and rods with rod insulators or garlands of disk insulators.

Console classification

Consoles are single-track and double-track (multi-track). Single-track consoles are of two types: inclined and straight - horizontal. The main advantage of an inclined console is that it requires a lower support height compared to a straight console, since with an inclined console, the rod is located horizontally and is attached to the support, approximately at the height of the carrier cable. The advantage of a straight console is that it allows a wider adjustment of the position of the carrier cable in the direction across the track and allows convenient placement of reinforcing wires on the same console.

The type of console that has received the most widespread use in our country. There is a horizontal overhang at the end of the console behind the point where the rod is attached to it, allowing you to adjust the position of the insulator in the direction across the track.

Consoles are usually made of two channels or angles fastened together at several points by welding or rivets. Channels or corners are located with a small gap between them, sufficient to accommodate the lug of thrust from the yoke for attaching the insulator. Consoles of tubular section and from I-beams can also be used. The console rod is made of round iron, and the regulation of the rod length during the installation of the console is carried out by means of the thread at the end of the rod.

A stepwise method of adjusting the length of the rod is also used by including between the rod and the part mounted on the support for its fastening adjusting strips made of flat iron with holes spaced at equal distances. On metal supports, the console and rod are attached to the corners fixed on the supports. The bracket for fastening the heel of the console has two welded segments of the angle with a hole for a stud with a head, through which the heel of the console is attached. The corner for attaching the rod has a through hole (in the case of fastening the rod on the thread) or is made in the same way as the corner for attaching the heel of the console (in the case of using adjusting strips). On wooden supports, the fastening part of the console heel is attached with capercaillie and has several holes for the possibility of adjusting the position of the console in height.

In areas equipped with compensated chain suspension, rotary consoles are used, usually tubular, hinged on supports.

When the supports are located on the inner side of the curve and on the transitional supports, instead of the reverse clamps, sometimes the reverse consoles are used, which have a vertical post that serves to fasten the clamp from the side opposite to the support. The purpose of the reverse consoles is the same as the reverse clamps. The use of reverse consoles has the disadvantage that, due to the location of the grounded parts close to the axis, the possibility of carrying out work under voltage near them is limited. On double-track and multi-track sections, if, due to the conditions of the terrain, it is impossible to place the suspension of each track on separate consoles, double-track consoles are sometimes used. Double-track consoles are usually supported by two rods and have a vertical stand along the axis between the tracks between the electrified tracks for attaching the second track retainer.

When a support with a double-track console is located on the inside of the curve, reverse double-track consoles are used. In addition to consoles for chain suspension, brackets for reinforcing wires, fixing brackets and corners for attaching wires anchored to the support are attached to the contact network supports. All these parts are mounted on wooden supports, usually with capercaillie or through bolts, on metal supports - with hook bolts.

Brackets for reinforcing wires and fixing brackets on newly mounted lines must be of such length that a distance of at least 0.8 m is maintained from the nearest edge of the support to live parts of the suspension

3. Economic section

3.1 Calculation of the cost of building a contact network on the stage

In the course project, it is necessary to estimate the cost of building a contact network on a stage or station. The initial data for the preparation of estimates for construction and installation work are specifications for contact network plans and prices for work.

We accept the exchange rate as of June 1, 2013 equal to 31.75.

The entire economic calculation is summarized in Table 3.1.

Table 3.1

Estimation of the cost of construction of a contact network on the stage

Name of work or costs	Units of measurement	Estimated cost c.u.	total amount
Construction works
Installation of reinforced concrete double supports in cup-type foundations, installed with a base plate by digging in at the station
Waterproofing of reinforced concrete supports
Installation of reinforced concrete anchors with braces by vibration immersion at the station and the stage
The cost of reinforced concrete supports type:
The cost of three-beam foundations of the type:
The cost of three-beam anchors type:
The cost of braces type:
The cost of tubular insulated galvanized consoles
The cost of embedded parts for mounting consoles	set
Minor unrecorded expenses
Overheads
The same for the installation of metal structures and their cost
Planned savings
Total costs:
Installation work
Rolling "on top" of the contact wire:
Solitary on the main roads
Contact suspension adjustment with two contact wires: elastic chain (spring)
Installation of one-sided rigid anchoring: carrying cable or single
Installation of one-sided compensated anchoring: contact wire
Installation of a combined compensated anchoring of a carrier cable and a single contact wire
Installation of a three-span interface of anchor sections without sectioning
Installation of the middle anchorage with compensated suspension
Installation of the first wire (reinforcing) on ​​suspension insulators, taking into account the installation of brackets and garlands of insulators
The cost of brackets type KF-6.5
Installation of the group ground wire
Installation of diode grounding
Installation of surge arrester and horn arrester
Small unaccounted works
Overheads
Planned savings
Total costs:
materials
Bimetallic wire BSM-1 with a diameter of 4 mm (strings)
Other materials not included in the price tag
Planned savings
Total costs:
Equipment
Disconnector RS3000/3.3-1U1/RSU-3000/3.3
Horn arresters with two gaps
Diode grounding ZD-1
Porcelain insulator with pestle PF-70V
Equipment charges
Total costs:
Cost cost:

4. Labor protection and traffic safety

4.1 Organizational and technical measures to ensure the safety of work on the contact network. Working conditions in the area of ​​the contact network

Works on the contact networks under tension

Work under voltage is carried out from isolated platforms for railcars and railcars, from removable insulating ladders. The peculiarity of these works is that the performer of the work is in direct contact with high voltage, so he must be reliably isolated from the ground and the possibility of touching grounded structures must be excluded.

Before work, they inspect the insulating parts of the towers, make sure that all parts are in good condition, wipe the stairs and insulators. Test the insulation with operating voltage directly from the contact network. To do this, after climbing to an isolated platform or ladder, without touching the contact network and being as far away from it as possible, touch one of the elements of the contact network under voltage (string, electrical connector or latch) with the hook of the shunt rod. It is not allowed for the shunt rod to approach the insulator at a distance of less than 1 m and touch the wire under significant mechanical load, since if the insulation of the tower or ladder fails, an arc occurs that can damage the insulator or cause the wire to burn.

After checking the insulation, the shunt rods are hung on the wires of the contact suspension and left in this position for the entire duration of the work. If movement occurs and it is necessary to temporarily remove the shunt rods, the worker, while on the site, should not touch the wires and structures.

A suspended shunt rod reliably controls the state of the insulation and equalizes the potential of all parts that are simultaneously touched by the worker. No more than three electricians can be and work at the same time on an isolated platform, and no more than two electricians can work on an insulating removable tower. They pass to the isolated sites one by one with the shunt rods removed. The insulating removable tower can be climbed by two electricians at the same time from both sides.

In contrast to work from towers, railcars and railcars, work from an insulating removable tower, as a rule, is performed, as a rule, without stopping the movement of trains. Therefore, in order to be able to remove it from the path in a timely manner, the team consists (depending on the weight of the tower) of at least four to five people, not counting the signalmen.

In sections with single-strand track chains, the tower is installed on the track in such a way that the wheel that is not isolated from its lower part is on the traction rail. When installing a removable tower on the ground, its lower part is connected to the traction rail with a grounding copper wire of the same cross section as the wire used for shunting.

They move an insulating tower, railcar or railcar when workers are on the work site only at the command of the work performer located there, who warns all his assistants working on the site to stop work and, making sure that they do not touch the wires, removes the shunt rods for the duration of the movement . The movement must be smooth at a speed of no more than 5 km / h for a removable tower and no more than 10 km / h for a railcar and a railcar.

Work under voltage is performed without the order of the energy manager, but with his permission. The energy dispatcher is informed of the place and nature of the work planned for execution, as well as the time of their completion.

If work is carried out in places of sectioning of the contact network (on an insulating junction, sectional insulator or mortise insulator separating two sections of the contact network), an order from the energy dispatcher is required. In this case, the sections must be shunted (the sectional disconnector is on), and the shunt rods are installed on the wires of both sections of the contact network. To equalize the potentials in sections and prevent the flow of equalizing current through the mounting devices at the work site, no more than one span between the supports, a removable shunt jumper made of copper flexible wire with a cross section of at least 50 mm 2 is installed.

Work under voltage is not allowed under pedestrian bridges, rigid crossbars and in other places where the distance to grounded structures or structures and wires under a different voltage is less than 0.8 m for direct current and 1 m for alternating current. Work under voltage during rain, fog and wet snow is not allowed, since in these conditions the leakage current through the insulating parts becomes dangerous. In order to avoid accidental overwhelm of wires and overturning of the detachable tower under voltage, they do not work at wind speeds above 12 m/s.

When working from insulating towers, it is prohibited to: leave tools and other objects on the working platform that may fall during the installation and removal of the tower; those working below to touch directly or through any objects to the removable tower above the grounded belt; carry out work in which forces are transmitted to the top of the tower, causing the danger of its overturning; move a removable tower on the ground while workers are on it.

In all cases, the manager and other employees strictly ensure that the possibility of shunting the insulating part of the tower or insulators of the isolated site with any objects (rods, wire, clamp, ladder, etc.) is excluded.

If it is necessary to climb onto a carrier cable and other wires, a light wooden ladder no more than 3 m long with hooks for hanging on a cable or wire is used. When working on a ladder, they are fixed to the cable with a safety belt sling.

Technical measures to ensure the safety of work under voltage

Technical measures to ensure the safety of work under voltage are:

- issuance of warnings for trains and fencing of the work site;

- performance of work only with the use of protective equipment;

- inclusion of disconnectors, imposition of stationary and portable shunt rods and jumpers;

- Illumination of the place of work in the dark.

When working in places of sectioning of the contact network under voltage (insulating interfaces of anchor sections, sectional insulators and mortise insulators), as well as when disconnecting loops of disconnectors, arresters, suction transformers from the contact network and installing inserts in the wires of the contact network, shunt rods installed on detachable insulating towers, insulating working platforms for railcars and railcars, as well as portable shunt rods and shunt jumpers.

The cross-sectional area of ​​copper flexible wires of these rods and jumpers must be at least 50 mm 2.

To connect the wires of different sections that ensure the transmission of traction current, it is necessary to use jumpers made of copper flexible wire with a cross-sectional area of ​​at least 70% of the cross-sectional area of ​​the connected wires.

When working on an insulating interface of anchor sections, on a sectional insulator separating two sections of the contact network, mortise insulators, sectional disconnectors shunting them should be switched on.

In all cases, a shunt jumper connecting the contact suspensions of adjacent sections must be installed at the place of work. The distance from the worker to this jumper should be no more than 1 mast span.

If the distance to the bypass sectional disconnector is more than 600 m, the cross-sectional area of ​​the bypass jumper at the work site must be at least 95 mm 2 for copper.

The technological process of a comprehensive inspection and repair of the console

Work on repair and inspection of the console is carried out with the removal of voltage from contact suspension directly from the support or using a 9 m ladder; with a rise to a height; without interruption in the movement of trains. According to the order, and the order of the energy manager. According to the technological map.

Comprehensive inspection and repair of the console

Table 4.1

Cast

Conditionsfulfillmentworks

The work is being done:

1. With stress relief contact suspension directly from the support or using a 9 m ladder; with a rise to a height; without interruption in the movement of trains.

2. According to the outfit, and the order of the energy manager.

3. Mechanisms, mounting devices, tools, protective equipment and signal accessories:

1. Ladder attached 9 m (when working on a conical reinforced concrete support) 1 pc.

2. Grounding rod according to the number specified in the order

3. Wrench 2 pcs.

3. Scraper 1 piece

4. "Fishing rod" rope 1 pc.

5. Pliers 1 pc.

6. Bench hammer 1 pc.

7. Indicator bracket or caliper with needle "sponges" 1 pc.

8. Writing pad with writing utensils 1 set

9. Dielectric gloves 1 pair.

10. Measuring ruler 1 pc.

11. Safety belt 2 pcs.

12. Protective helmet according to the number of performers.

13. Signal vest according to the number of performers.

14. Signal accessories 1 set

15. First aid kit 1 set

Table 4.2

Norm of time for one console In pers. h.

Types of jobs	When performing work
	directly	from a ladder
Comprehensive condition check and repair:
Single-track non-insulated console on an intermediate support
The same on the transitional support of the mates of the anchor sections
Knots of insulation of fasteners of elements of an insulated console on a support
- double-track console
Adjustment of the position of the console along the track with one support cable

Notes:

1. When adjusting the position of the console with hanging cables (wires) more than one. To the norm of time, add 0.15 people to each suspension point. hours when working from a support and 0.24 people. h - when working with a ladder.

2. When checking the condition and repairing a single-track cantilever with a strut, increase the time norm by 1.1 times, respectively.

3. When checking the condition and repairing a single-track non-insulated console with a reverse locking post, increase the time rate by 1.25 times, respectively.

preparatoryworkandadmissionwork

1. On the eve of work, submit to the energy dispatcher an application for work with stress relief in the work area, directly from a support or using a 9 m ladder, climbing to a height, without interrupting train traffic, indicating the time, place and nature of work.

2. Get a work order and briefing from the person who issued it.

3. In accordance with the results of detours and detours with inspection, diagnostic tests and measurements, select the necessary materials and parts to replace worn ones. Check by external inspection their condition, completeness, workmanship and protective coating, drive the threads on all threaded connections and apply a smear on it.

4. Select mounting devices, protective equipment, signal accessories and tools, check their serviceability and test dates. Load them, as well as selected materials and parts onto the vehicle, organize delivery together with the team to the place of work.

5. Upon arrival at the place of work, conduct a current safety briefing with a signature of everyone in the outfit.

6. Receive an order from the energy dispatcher indicating the removal of voltage in the work area, the start and end time of work.

7. Ground the de-energized wires and equipment with portable ground rods on both sides of the work site in accordance with the work order.

8. When working on a reinforced concrete conical support, install and fix a 9 m ladder on the support.

9. To carry out the admission to the production of works.

2.3 Sequential workflow

1. The performer should climb to the place of work directly on the support or on the ladder.

2. Visually check the condition of the attachment points of the heel and the drawbars of the console on the support, as well as the connections of the grounding descent to them. If there are embedded parts on a reinforced concrete support, check the condition of the insulating bushings.

At the interfaces of the anchor sections of the compensated suspension, check the position and fastening of the traverses on the support.

Pay attention to the provision of hinged mobility in the horizontal and vertical planes when moving the consoles.

3. Check the distance from the top of the reinforced concrete support to the cantilever tie rod clamp. It must be at least 200 mm. On a support with embedded parts, the rod must be attached to the part installed in the second hole.

4. Check, if present, the condition and attachment of the strut to the console bracket and support. The strut should be in a taut (compressed) state, slightly loaded. The point of attachment of the strut to the console bracket must be no more than 300 mm from the part for attaching the latch.

5. On insulated consoles, check the condition and repair the attachment points of the rods, struts and brackets of the console on the support (including traverses on the transitional supports of the anchor sections and insulators in these nodes).

Checking the remaining units and elements of the insulated console is carried out under voltage in the process of checking the condition and repairing the chain suspension, as well as non-insulating and insulating mates of the anchor sections, respectively, according to Technological maps No. 2.1.1, 2.1.2 and No. 2,2.1.

6. For a double-track console, check the correct assembly of the heel of the console, the presence of rollers (rivets) at the junction of the transition piece with the console bracket.

Check tension adjustment. Both rods must be loaded evenly, the tension is checked by vibration when hitting the guys with a metal object.

7. Check the correct installation of the console in the vertical plane. The trunk of the curved consoles and the bracket of the horizontal consoles must be horizontal.

Notes:

1. Check the condition, determine the extent of damage and the degree of their danger in accordance with the Guidelines for the maintenance and repair of the supporting structures of the contact set (K-146-96).

2. When checking the condition of all elements and their attachment points, identify the presence of damage: deformations, delaminations, cracks and corrosion of the metal.

Pay special attention to the condition of the welds, the presence of lock nuts and cotter pins, as well as the wear of the elements in the joints; will evaluate the condition of the protective anti-corrosion coating and determine the need for repainting.

Tighten loose fasteners, install the missing lock nuts, replace worn cotter pins and insulator locks (detail K-078), apply anti-corrosion grease to threaded connections.

Deformation or displacement of console elements and fasteners is not allowed

3. When checking the condition of the insulators, clean them from contamination. Insulators with persistent contamination of more than yj of the insulating surface or defects.

Endingworks

1. Disconnect the ladder from the support and lower it to the ground.

2. Remove ground rods.

3. Collect materials, mounting devices, tools, protective equipment and load them onto the vehicle.

4. Notify the energy dispatcher about the completion of work.

5. Return to the EChK production base.

Conclusion

In this graduation project, a mechanical calculation of the contact suspension M-95 + 2NlFO-100 was made. As a result of these calculations, data on the load on the wires from wind, ice and dead weight were obtained. Based on these data, the design mode of maximum wind was selected.

Based on the design mode, the span lengths on the stage were calculated: 55 m; 70 m; 56 m; 50 m; 66 m. According to the task for the diploma design, a plan of the contact network of the stage was built, in which equipment for the corresponding type of current was selected and summarized in the specification.

- An embankment with a height of more than 5 meters

Straight section of the haul and curves of various radii;

Excavation up to 7 meters deep;

In the economic section, the cost of structures on the contact network on the stage is calculated.

In the technological section, the issue is considered - dangerous places on the contact network.

In the labor protection section, technical measures are considered that ensure the safety of work under voltage

Completed: tracing co...

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Figure 1.6.1 - Calculation scheme for the selection of supports

The vertical load from the weight of the contact suspension for the design mode is determined by the formula:

(1.6.1)

-m mode, N/m;

L- the estimated length of the span, equal to half the sum of the lengths of the spans adjacent to the design support, m;

G and - the load from the weight of the insulators, taken in the calculations for direct current -150 N;

G f" - load from the weight of half of the fixation node, G f = 200 N.

Similarly, the vertical load is determined from the weight of the reinforcing wire for the design mode - j.

(1.6.2)

With 3-phase overhead lines or DPR, it is advisable to sum up the loads from the wires and select their centers of gravity. Similar actions are carried out with brackets.

Vertical loads from the weight of the bracket console ( G book, G kr) are taken according to their standard drawings with an increase in this load in icy conditions.

The horizontal load on the support under the action of wind on the wires of the contact network is determined from the expression

(1.6.3)

where is the th wire of the contact network at
i- m mode, N/m;

i- contact network wire (instead of i“n” is indicated for the supporting cable, “k” for the contact wire, “pr” for the reinforcing wire).

The force on the support from a change in the direction of the wire on the curve is determined by the formula:

(1.6.4)

where Hij- tension i-th wire in j-m mode, N;

R is the radius of the curve, m.

The load on the support from a change in the direction of the wires when retracting it to the anchorage is determined from the expression:

(1.6.5)

where Z= G + 0.5 D- the distance from the axis of the path to the place of fastening of the anchoring of the wire, equal to the sum of the dimension (D) and half the diameter ( D) supports.

The force from changing the direction of the contact wires with zigzags on straight sections of the path, if they have equal and opposite values ​​​​on adjacent supports, is determined by the formula

(1.6.6)

where a- the size of the zigzag on the straight section of the path, m.

The load from wind pressure on the support is determined from the expression:

where Сx- aerodynamic coefficient, for reinforced concrete supports, Сx= 0,7;

V p is the calculated wind speed, m/s;

S op is the area of ​​the surface on which the wind acts (the area of ​​the diametrical section of the support):

(1.6.7)

where d, D– support diameters, respectively, upper and lower, m;

h op is the height of the support, m.

Let's calculate the loads on the intermediate support on the straight section of the haul for the most severe mode (ice with wind):

Horizontal load on the support under the action of wind on the wires of the COP:

Surface area affected by wind:

Table 6.1.1 - Results of calculation of supports, N∙m

According to this moment, we select the support, provided that it should be less than the standard moment. We choose a support SS 136.6–1 with a standard moment = 44000 N∙m.

Equipment selection

During the reconstruction of the section of the contact network, supports of the CC136.6-1 type were used. Supports of type СC136.6–1 were installed in the foundations ТСС 4.5–4. Three-beam foundations with a bevel are designed for anchor installation of separate reinforced concrete and metal supports of the contact network.

For anchoring the wires, TAC-5.0 type anchors were used. Additionally, base plates OPF foundation and OP-1 type 1 were used.

The contact suspension was mounted on insulated tubular consoles of the KIS-1 type and direct and reverse clamps (FIP and FIO), wire brackets MG-III.

All equipment was selected according to standard designs KS 160-4.1; 6291, KS-160.12, developed by CJSC "Universal-contact networks".

Note: The marking of the foundation TSS 4.5–4 is deciphered as follows: T - three-beam, C - glass type, C - beveled, 4.5 - size in meters, 4 - bearing capacity group, 79 kNm.

TAC anchor marking - 5.0 stands for: T - three-beam, A - anchor, C - with a bevel, 5.0 - length in meters. KIS console marking: K - console, I - insulated, C - steel. Marking of FIP locks: F - articulated lock, P - straight, O - reverse, 1 - designation of the size of the lock rod.

The contact network plan is given in Appendix A.

Contact network is a set of devices for transmitting electricity from traction substations to EPS through pantographs. It is part of the traction network and for rail electrified transport it usually serves as its phase (with alternating current) or pole (with direct current); the other phase (or pole) is the rail network. The contact network can be made with a contact rail or with a contact suspension.
In a contact network with a contact suspension, the main elements are the following: wires - a contact wire, a supporting cable, a reinforcing wire, etc .; supports; supporting and fixing devices; flexible and rigid cross members (consoles, clamps); insulators and fittings for various purposes.
A contact network with a contact suspension is classified according to the type of electrified transport for which it is intended - railway. mainline, city (tram, trolley bus), quarry, mine underground rail transport, etc.; by the nature of the current and the rated voltage of the EPS powered by the network; on the placement of the contact suspension relative to the axis of the rail track - for the central current collection (on the main railway transport) or side (on the ways of industrial transport); by type of contact suspension - with a simple, chain or special; according to the features of the anchoring of the contact wire and the carrier cable, the interfaces of the anchor sections, etc.
The contact network is designed to work outdoors and therefore is exposed to climatic factors, which include: ambient temperature, humidity and air pressure, wind, rain, frost and ice, solar radiation, the content of various contaminants in the air. To this it is necessary to add thermal processes that occur when the traction current flows through the elements of the network, the mechanical effect on them from the current collectors, electrocorrosion processes, numerous cyclic mechanical loads, wear, etc. All devices of the contact network must be able to withstand the action of the listed factors and provide high current collection quality in any operating conditions.
Unlike other power supply devices, the contact network does not have a reserve, therefore, increased requirements are imposed on it in terms of reliability, taking into account which its design, construction and installation, maintenance and repair are carried out.

Contact network design

When designing a contact network (CS), the number and brand of wires are selected based on the results of calculations of the traction power supply system, as well as traction calculations; determine the type of contact suspension in accordance with the maximum speeds of the ERS and other current collection conditions; find the span lengths (ch. arr. according to the conditions for ensuring its wind resistance, and at high speeds - and a given level of elasticity unevenness); choose the length of anchor sections, types of supports and supporting devices for hauls and stations; develop CS designs in artificial structures; they place supports and draw up plans for the contact network at stations and spans with the coordination of wire zigzags and taking into account the implementation of air arrows and sectioning elements of the contact network (insulating interfaces of anchor sections and neutral inserts, sectional insulators and disconnectors).
The main dimensions (geometric indicators) characterizing the placement of the contact network relative to other devices are the height H of hanging the contact wire above the level of the top of the rail head; distance A from live parts to grounded parts of structures and rolling stock; the distance G from the axis of the extreme path to the inner edge of the supports, located at the level of the rail heads, are regulated and largely determine the design of the elements of the contact network (Fig. 8.9).

Improving the design of the contact network is aimed at increasing its reliability while reducing the cost of construction and operation. Reinforced concrete supports and foundations of metal supports are made with protection against electrocorrosive effects of stray currents on their reinforcement. An increase in the service life of contact wires is achieved, as a rule, by using inserts with high antifriction properties (carbon, including metal-containing; metal-ceramic, etc.) on current collectors, by choosing a rational design of current collectors, and by optimizing current collection modes.
To improve the reliability of the contact network, ice is melted, incl. without interruption of train traffic; wind-resistant contact suspensions are used, etc. The efficiency of work on the contact network is facilitated by the use of remote control for remote switching of sectional disconnectors.

Wire anchoring

Anchoring wires - attaching the wires of the contact suspension through the insulators and fittings included in them to the anchor support with the transfer of their tension to it. Anchoring of wires can be uncompensated (rigid) or compensated (Fig. 8.16) through a compensator that changes the length of the wire if its temperature changes while maintaining the specified tension.

In the middle of the anchor section of the contact suspension, an average anchoring is performed (Fig. 8.17), which prevents unwanted longitudinal movements towards one of the anchorages and allows you to limit the damage zone of the contact suspension when one of its wires breaks. The cable of the middle anchorage is attached to the contact wire and the carrier cable with appropriate fittings.

Wire strain compensation

Wire tension compensation (automatic control) of the contact network when their length changes as a result of temperature effects is carried out by compensators of various designs - block-load, with drums of various diameters, hydraulic, gas-hydraulic, spring, etc.
The simplest is a block-cargo compensator, consisting of a load and several blocks (chain hoist), through which the load is attached to the anchored wire. The most widespread is the three-block compensator (Fig. 8.18), in which the fixed block is fixed on a support, and two movable ones are embedded in loops formed by a cable carrying the load and fixed at the other end in the stream of the fixed block. The anchored wire is attached to the movable block through insulators. In this case, the weight of the load is 1/4 of the nominal tension (a gear ratio of 1:4 is provided), but the movement of the load is twice that of a two-to-6-arm compensator (with one moving block).

compensators with drums of different diameters (Fig. 8.19), cables connected with anchored wires are wound on a drum of small diameter, and a cable connected to a garland of loads is wound on a drum of a larger diameter. The braking device is used to prevent damage to the contact suspension in the event of a wire break.

Under special operating conditions, especially with limited dimensions in artificial structures, minor temperature differences in heating wires, etc., compensators of other types are also used for catenary wires, fixing cables and rigid crossbars.

Contact wire holder

Contact wire clamp - a device for fixing the position of the contact wire in a horizontal plane relative to the axis of current collectors. On curved sections, where the levels of the rail heads are different and the axis of the pantograph does not coincide with the axis of the track, non-articulated and articulated clamps are used.
The non-articulated latch has one rod, pulling the contact wire from the pantograph axis to the support (stretched latch) or from the support (compressed latch) by the size of the zigzag. On electrified railways e. non-articulated clamps are used very rarely (in the anchored branches of the contact suspension, on some air arrows), because the “hard point” formed with these clamps on the contact wire worsens the current collection.

The articulated latch consists of three elements: the main rod, the stand and the additional rod, at the end of which the fixing clip of the contact wire is attached (Fig. 8.20). The weight of the main rod is not transferred to the contact wire, and it takes only part of the weight of the additional rod with a fixing clip. The rods are shaped to ensure reliable passage of the current collectors when they squeeze out the contact wire. For high-speed and high-speed lines, lightweight additional rods are used, for example, made of aluminum alloys. With a double contact wire, two additional rods are installed on the rack. On the outer side of curves of small radii, flexible clamps are mounted in the form of a conventional additional rod, which is attached through a cable and an insulator to a bracket, rack, or directly to a support. On flexible and rigid crossbars with fixing cables, strip retainers (similar to an additional rod) are usually used, hinged with clamps with an eye mounted on the fixing cable. On rigid crossbars, it is also possible to mount clamps on special racks.

Anchor section

Anchor section - a contact suspension section, the boundaries of which are anchor supports. The division of the contact network into anchor sections is necessary to include devices in the wires that maintain the tension of the wires when their temperature changes and to carry out longitudinal sectioning of the contact network. This division reduces the damage zone in the event of a break in the wires of the contact suspension, facilitates installation, tech. maintenance and repair of the contact network. The length of the anchor section is limited by permissible deviations from the nominal value of the tension of the catenary wires set by the compensators.
Deviations are caused by changes in the position of the strings, detents and consoles. For example, at speeds up to 160 km/h, the maximum length of the anchor section with two-sided compensation on straight sections does not exceed 1600 m, and at speeds of 200 km/h, no more than 1400 m is allowed. In curves, the length of the anchor sections decreases the more, the greater the length curve and its radius is smaller. To move from one anchor section to the next, non-insulating and insulating mates are performed.

Conjugation of anchor sections

Pairing of anchor sections is a functional combination of two adjacent anchor sections of the contact suspension, which ensures a satisfactory transition of the ERS pantographs from one of them to the other without violating the current collection mode due to the appropriate placement in the same (transitional) spans of the contact network of the end of one anchor section and the beginning of another. There are non-insulating mates (without electrical sectioning of the contact network) and insulating (with sectioning).
Non-insulating mates are performed in all cases when it is required to include compensators in the wires of the catenary. This achieves mechanical independence of the anchor sections. Such mates are mounted in three (Fig. 8.21, a) and less often in two spans. On high-speed lines, interfacing is sometimes performed in 4-5 spans due to higher requirements for the quality of the current collection. On non-insulating mates there are longitudinal electrical connectors, the cross-sectional area of ​​which must be equivalent to the cross-sectional area of ​​the wires of the contact network.

Insulating interfaces are used when it is necessary to section off the contact network, when, in addition to mechanical, it is necessary to ensure the electrical independence of the mating sections. Such pairings are arranged with neutral inserts (sections of the contact suspension, on which there is normally no voltage) and without them. In the latter case, three- or four-span mates are usually used, placing the contact wires of the mating sections in the middle span (spans) at a distance of 550 mm from one another (Fig. 8.21.6). In this case, an air gap is formed, which, together with the insulators included in the raised contact suspensions at the transitional supports, ensures the electrical independence of the anchor sections. The transition of the pantograph skid from the contact wire of one anchor section to another occurs in the same way as with non-insulating pairing. However, when the pantograph is in the middle span, the electrical independence of the anchor sections is violated. If such a violation is unacceptable, neutral inserts of different lengths are used. It is chosen such that, with several pantographs of one train raised, simultaneous overlapping of both air gaps is excluded, which would lead to a short circuit of wires powered by different phases and under different voltages. In order to avoid burnout of the contact wire of the EPS, the interface with the neutral insert takes place on the freewheel, for which, 50 m before the start of the insert, the signal sign “Turn off the current” is installed, and after the end of the insert, with electric locomotive traction after 50 m and with multiple unit traction after 200 m, the sign “ Turn on the current "(Fig. 8.21, c). In areas with high-speed traffic, automatic means of switching off the current on the EPS are necessary. In order to be able to withdraw the train when it is forced to stop under the neutral insert, sectional disconnectors are provided for temporarily supplying voltage to the neutral insert from the direction of train movement.

Sectioning of the contact network

Sectioning of the contact network - division of the contact network into separate sections (sections), electrically disconnected by insulating mates of anchor sections or sectional insulators. Insulation can be broken during the passage of the ERS pantograph along the section boundary; if such a short circuit is unacceptable (when adjacent sections are powered from different phases or they belong to different traction power supply systems), neutral inserts are placed between the sections. Under operating conditions, the electrical connection of individual sections is carried out, including sectional disconnectors installed in appropriate places. Sectioning is also necessary for the reliable operation of power supply devices in general, operational maintenance and repair of the contact network with power outages. The sectioning scheme provides for such a mutual arrangement of sections, in which the disconnection of one of them has the least effect on the organization of train traffic.
Sectioning of the contact network is longitudinal and transverse. With longitudinal sectioning, the contact network of each main path is separated along the electrified line at all traction substations and sectioning posts. In separate longitudinal sections, a contact network of hauls, substations, sidings and passing points is distinguished. At large stations with several electrified parks or track groups, the contact network of each park or track groups forms independent longitudinal sections. At very large stations, sometimes the contact network of one or both necks is separated into separate sections. The contact network is also sectioned in long tunnels and on some bridges with a ride below. With transverse sectioning, the contact network of each of the main tracks is separated along the entire length of the electrified line. At stations with significant track development, additional transverse sectioning is used. The number of transverse sections is determined by the number and purpose of individual tracks, and in some cases by the starting modes of the ERS, when it is necessary to use the cross-sectional area of ​​contact suspensions of adjacent tracks.
Sectioning with mandatory grounding of the disconnected section of the contact network is provided for tracks where people can be on the roofs of wagons or locomotives, or tracks near which lifting and transport mechanisms operate (loading and unloading, outfitting tracks, etc.). To ensure greater safety of those working in these places, the corresponding sections of the contact network are connected to other sections by sectional disconnectors with grounding knives; these blades ground the disconnected sections when the disconnectors are disconnected.

On fig. 8.22 shows an example of a power supply and sectioning scheme for a station located on a double-track section of a line electrified on alternating current. The diagram shows seven sections - four on hauls and three at the station (one of them with mandatory grounding when it is turned off). The contact network of the left haul tracks and the station is powered by one phase of the power system, and the right haul tracks are powered by the other. Accordingly, sectioning was performed using insulating mates and neutral inserts. In areas where ice melting is required, two sectional disconnectors with motor drives are installed on the neutral insert. If ice melting is not provided, one sectional disconnector with a manual drive is sufficient.

For sectioning the contact network of the main and side networks at the stations, sectional insulators are used. In some cases, sectional insulators are used to form neutral inserts on the AC contact network, which the EPS passes without consuming current, as well as on tracks where the length of the ramps is insufficient to accommodate insulating mates.
Connection and disconnection of various sections of the contact network, as well as connection with supply lines, is carried out using sectional disconnectors. On AC lines, as a rule, disconnectors of a horizontal rotary type are used, on DC lines - vertically chopping. The disconnector is controlled remotely from the consoles installed in the duty station of the contact network area, in the premises of those on duty at the stations and in other places. The most critical and frequently switched disconnectors are installed in the dispatch telecontrol network.
There are longitudinal disconnectors (for connecting and disconnecting the longitudinal sections of the contact network), transverse (for connecting and disconnecting its transverse sections), feeder, etc. They are designated by the letters of the Russian alphabet (for example, longitudinal -A, B, C, G; transverse - P ; feeder - F) and numbers corresponding to the numbers of tracks and sections of the contact network (for example, P23).
To ensure the safety of work on the disconnected section of the contact network or near it (in the depot, on the ways of equipping and inspecting the roof equipment of the EPS, on the ways of loading and unloading cars, etc.), disconnectors with one grounding knife are installed.

Frog

Air switch - formed by the intersection of two contact suspensions above the turnout; designed to ensure a smooth and reliable passage of the pantograph from the contact wire of one path to the contact wire of another. The crossing of wires is carried out by superimposing one wire (usually an adjacent path) on another (Fig. 8.23). To lift both wires when the current collector approaches the air arrow, a restrictive metal pipe 1-1.5 m long is fixed on the lower wire. The upper wire is placed between the tube and the lower wire. The crossing of the contact wires over a single turnout is carried out with the displacement of each wire to the center from the axes of the tracks by 360-400 mm and is located where the distance between the inner faces of the heads of the connecting rails of the cross is 730-800 mm. At cross turnouts and at the so-called. At blind intersections, the wires cross over the center of the turnout or intersection. Air gunners perform, as a rule, fixed. To do this, clamps are installed on the supports that hold the contact wires in a predetermined position. On station tracks (except for the main ones), the switches can be made non-fixed if the wires above the turnout are located in the position specified by adjusting the zigzags at the intermediate supports. Contact suspension strings located near the arrows must be double. Electrical contact between contact suspensions forming an air arrow is provided by an electrical connector installed at a distance of 2-2.5 m from the point of intersection on the side of the wit. To increase reliability, switch designs are used with additional cross-links between the wires of both contact suspensions and sliding supporting double strings.

Contact network supports

Contact network supports - structures for fixing the supporting and fixing devices of the contact network, perceiving the load from its wires and other elements. Depending on the type of supporting device, the supports are divided into cantilever (single-track and double-track execution); racks of rigid crossbars (single or paired); supports of flexible crossbars; feeder (with brackets only for supply and exhaust wires). Supports on which there are no supporting, but there are fixing devices, are called fixing. Cantilever supports are divided into intermediate ones - for attaching one contact suspension; transitional, installed at the junctions of the anchor sections, - for fastening two contact wires; anchor, perceiving the force from the anchoring of wires. As a rule, supports perform several functions at the same time. For example, the support of the flexible crossbar can be anchored, consoles can be hung on the uprights of the rigid crossbar. Brackets for reinforcing and other wires can be fixed to the support posts.
Supports are made of reinforced concrete, metal (steel) and wood. On domestic railways e. mainly used supports made of prestressed reinforced concrete (Fig. 8.24), conical centrifuged, standard length 10.8; 13.6; 16.6 m. Metal supports are installed in cases where it is impossible to use reinforced concrete ones due to their bearing capacity or dimensions (for example, in flexible crossbars), as well as on lines with high-speed traffic, where there are increased requirements for the reliability of support structures. Wooden supports are used only as temporary.

For DC sections, reinforced concrete poles are made with additional bar reinforcement located in the foundation part of the poles and designed to reduce damage to the pole reinforcement by electrocorrosion caused by stray currents. Depending on the method of installation, reinforced concrete supports and racks of rigid crossbars are separate and inseparable, installed directly into the ground. The required stability of inseparable supports in the ground is provided by the upper bed or base plate. In most cases, inseparable supports are used; separate ones are used with insufficient stability of inseparable ones, as well as in the presence of groundwater, which makes it difficult to install inseparable supports. In anchor reinforced concrete supports, braces are used, which are installed along the path at an angle of 45 ° and attached to reinforced concrete anchors. Reinforced concrete foundations in the above-ground part have a cup 1.2 m deep, in which supports are installed and then the sinuses of the cup are sealed with cement mortar. To deepen foundations and supports into the ground, the vibration immersion method is mainly used.
Metal supports of flexible crossbars are usually made of a tetrahedral pyramidal shape, their standard length is 15 and 20 m. In areas characterized by increased atmospheric corrosion, metal cantilever supports 9.6 and 11 m long are fixed in the ground on reinforced concrete foundations. Cantilever supports are installed on prismatic three-beam foundations, flexible crossbeam supports are installed either on separate reinforced concrete blocks or on pile foundations with grillages. The base of the metal supports is connected to the foundations with anchor bolts. To fix supports in rocky soils, heaving soils of permafrost and deep seasonal freezing regions, in weak and swampy soils, etc., foundations of special structures are used.

Console

The console is a supporting device fixed on a support, consisting of a bracket and a rod. Depending on the number of overlapped paths, the console can be one-, two-, and rarely multi-track. To eliminate the mechanical connection between contact suspensions of different tracks and to increase reliability, single-track consoles are more often used. Uninsulated or grounded consoles are used, in which the insulators are located between the carrier cable and the bracket, as well as in the latch rod, and insulated consoles with insulators placed in the brackets and rods. Uninsulated consoles (Fig. 8.25) can be curved, inclined and horizontal in shape. For supports installed with an increased dimension, consoles with struts are used. At the junctions of the anchor sections, when mounting two consoles on one support, a special traverse is used. Horizontal consoles are used in cases where the height of the supports is sufficient to secure the inclined rod.

With isolated consoles (Fig. 8.26), it is possible to carry out work on the supporting cable near them without turning off the voltage. The absence of insulators on uninsulated consoles ensures greater stability of the position of the carrier cable under various mechanical influences, which favorably affects the current collection process. The brackets and rods of the consoles are fixed on supports with the help of heels, which allow them to be rotated along the axis of the track by 90 ° in both directions relative to the normal position.

Flexible cross member

Flexible crossbar - a supporting device for hanging and fixing the wires of the contact network located above several tracks. A flexible cross member is a system of cables stretched between supports across electrified tracks (Fig. 8.27). The transverse carrying cables take all vertical loads from the wires of the chain hangers, the cross member itself and other wires. The sag of these cables must be at least Vio the span between the supports: this reduces the effect of temperature on the height of the catenary hangers. To increase the reliability of the crossbars, at least two transverse load-bearing cables are used.

The fixing cables perceive horizontal loads (the upper one - from the carrying cables of chain suspensions and other wires, the lower one - from contact wires). The electrical isolation of the cables from the supports makes it possible to maintain the contact network without turning off the voltage. All cables to regulate their length are fixed on supports with threaded steel rods; in some countries, special dampers are used for this purpose, mainly for fixing contact suspension at stations.

current collection

Current collection - the process of transferring electrical energy from a contact wire or contact rail to the electrical equipment of a moving or stationary ERS through a current collector that provides sliding (on the main, industrial and most urban electric transport) or rolling (on some types of ERS of urban electric transport) electrical contact. Breaking the contact during current collection leads to the occurrence of non-contact arc erosion, resulting in intense wear of the contact wire and the contact inserts of the current collector. When the contact points are overloaded with current in the driving mode, contact electroexplosive erosion (sparking) and increased wear of the contacting elements occur. Long-term overload of the contact with the operating current or short-circuit current when the EPS is stopped can lead to burnout of the contact wire. In all these cases, it is necessary to limit the lower limit of contact pressure for given operating conditions. Excessive contact pressure, incl. as a result of aerodynamic impact on the pantograph, an increase in the dynamic component and the resulting increase in the vertical squeezing of the wire, especially at clamps, on overhead arrows, at the junction of anchor sections and in the area of ​​artificial structures, can reduce the reliability of the contact network and pantographs, as well as increase the wear rate wires and contact inserts. Therefore, the upper limit of contact pressure also needs to be normalized. Optimization of current collection modes is provided by coordinated requirements for contact network devices and current collectors, which guarantees high reliability of their operation at minimum reduced costs.
The quality of the current collection can be determined by different indicators (the number and duration of mechanical contact disturbances in the calculated section of the path, the degree of stability of the contact pressure, close to the optimal value, the wear rate of the contact elements, etc.), which largely depend on the design of the interacting systems - the contact network and pantographs, their static, dynamic, aerodynamic, damping and other characteristics. Despite the fact that the current collection process depends on a large number of random factors, the results of research and operating experience allow us to identify the fundamental principles for creating current collection systems with the required properties.

Rigid cross member

Rigid crossbar - serves to suspend the wires of the contact network located above several (2-8) tracks. A rigid cross member is made in the form of a block metal structure (crossbar) mounted on two supports (Fig. 8.28). Such cross members are also used for opening spans. The crossbar with the uprights is hingedly or rigidly connected with the help of struts, which allow unloading it in the middle of the span and reducing steel consumption. When placing lighting fixtures on the crossbar, a flooring with railings is performed on it; provide a ladder for climbing to the supports of service personnel. Install rigid cross bars. arr. at stations and points.

insulators

Insulators - devices for isolating wires of a contact network that are energized. There are insulators according to the direction of application of loads and the place of installation - suspended, tension, fixative and cantilever; by design - dish-shaped and rod; by material - glass, porcelain and polymer; insulators also include insulating elements
Suspension insulators - porcelain and glass dish-shaped - are usually connected in garlands of 2 on DC lines and 3-5 (depending on air pollution) on AC lines. Tension insulators are installed in wire anchorages, in load-bearing cables above sectional insulators, in fixing cables of flexible and rigid crossbars. Retaining insulators (fig. 8.29 and 8.30) differ from all others by the presence of an internal thread in the hole of the metal cap for fixing the pipe. On alternating current lines, rod insulators are usually used, and on direct current lines, disc insulators are also used. In the latter case, another disc insulator with an earring is included in the main rod of the articulated retainer. Cantilever porcelain rod insulators (Fig. 8.31) are installed in struts and rods of insulated consoles. These insulators must have increased mechanical strength, since they work in bending. In sectional disconnectors and horn arresters, porcelain rod insulators are usually used, less often disc insulators. In sectional insulators on DC lines, polymer insulating elements are used in the form of rectangular bars made of press material, and on AC lines, in the form of cylindrical fiberglass rods, which are covered with electrical protective covers made of fluoroplastic pipes. Polymeric rod insulators with fiberglass cores and silicone elastomer ribs have been developed. They are used as hanging, sectioning and fixing; they are promising for installation in struts and rods of insulated consoles, in cables of flexible cross members, etc. In areas of industrial air pollution and in some artificial structures, periodic cleaning (washing) of porcelain insulators is carried out using special mobile equipment.

Contact suspension

Contact suspension - one of the main parts of the contact network, is a system of wires, the relative position of which, the method of mechanical connection, material and cross section provide the necessary quality of current collection. The design of the contact suspension (KP) is determined by economic feasibility, operating conditions (the maximum speed of the ERS, the highest current taken by pantographs), and climatic conditions. The need to ensure reliable current collection at increasing speeds and power of the EPS determined the trends in changing the designs of suspensions: first simple, then single with simple strings and more complex - single spring, double and special, in which to ensure the desired effect, ch. arr. alignment of the vertical elasticity (or rigidity) of the suspension in the span, space-cable systems with an additional cable or others are used.
At speeds up to 50 km / h, a satisfactory quality of current collection is ensured by a simple contact suspension, consisting only of a contact wire suspended from supports A and B of the contact network (Fig. 8.10, a) or transverse cables.

The quality of the current collection is largely determined by the sag of the wire, which depends on the resulting load on the wire, which is the sum of the dead weight of the wire (with ice along with ice) and wind load, as well as the length of the span and tension of the wire. The quality of the current collection is greatly influenced by the angle a (the smaller it is, the worse the quality of the current collection), the contact pressure changes significantly, shock loads appear in the support zone, there is increased wear of the contact wire and the current collector inserts of the current collector. It is possible to somewhat improve the current collection in the support zone by applying the suspension of the wire at two points (Fig. 8.10.6), which, under certain conditions, provides reliable current collection at speeds up to 80 km / h. It is possible to noticeably improve the current collection with a simple suspension only by significantly reducing the length of the spans in order to reduce the sag, which in most cases is uneconomical, or by using special wires with significant tension. In this regard, chain suspensions are used (Fig. 8.11), in which the contact wire is suspended from the carrier cable using strings. A suspension consisting of a carrier cable and a contact wire is called single; in the presence of an auxiliary wire between the carrier cable and the contact wire - double. In a chain suspension, the carrier cable and the auxiliary wire are involved in the transmission of traction current, so they are connected to the contact wire with electrical connectors or conductive strings.

The main mechanical characteristic of a contact suspension is considered to be elasticity - the ratio of the height of the contact wire to the force applied to it and directed vertically upwards. The quality of the current collection depends on the nature of the change in elasticity in the span: the more stable it is, the better the current collection. In simple and conventional chain hangers, the mid-span elasticity is higher than that of supports. Elasticity equalization in the span of a single suspension is achieved by installing spring cables 12-20 m long, on which vertical strings are attached, as well as by the rational arrangement of ordinary strings in the middle part of the span. Double pendants have more permanent elasticity, but they are more expensive and more difficult. To obtain a high rate of uniformity of elasticity distribution in the span, various methods are used to increase it in the zone of the support node (installation of spring shock absorbers and elastic rods, torsion effect from cable twisting, etc.). In any case, when developing suspensions, it is necessary to take into account their dissipative characteristics, i.e., resistance to external mechanical loads.
The contact suspension is an oscillatory system, therefore, when interacting with current collectors, it can be in a state of resonance caused by the coincidence or frequency multiplicity of its natural oscillations and forced oscillations, determined by the speed of the current collector along the span with a given length. In the event of resonance phenomena, a noticeable deterioration in current collection is possible. Limiting for the current collection is the speed of propagation of mechanical waves along the suspension. If this speed is exceeded, the current collector has to interact, as it were, with a rigid, non-deformable system. Depending on the normalized specific tension of the suspension wires, this speed can be 320-340 km/h.
Simple and chain hangers consist of separate anchor sections. Suspension fastenings “at the ends of the anchor sections can be rigid or compensated. On the main etc. mainly compensated and semi-compensated suspensions are used. In semi-compensated suspensions, compensators are available only in the contact wire, in compensated ones - also in the carrier cable. In this case, in the event of a change in the temperature of the wires (due to the passage of currents through them, changes in the ambient temperature), the sag of the carrier cable, and, consequently, the vertical position of the contact wires, remain unchanged. Depending on the nature of the change in the elasticity of the suspensions in the span, the sag of the contact wire is taken in the range from 0 to 70 mm. Vertical adjustment of semi-compensated suspensions is carried out so that the optimal sag of the contact wire corresponds to the average annual (for a given area) ambient temperature.
The structural height of the suspension - the distance between the carrier cable and the contact wire at the suspension points - is chosen based on technical and economic considerations, namely, taking into account the height of the supports, compliance with the current vertical dimensions of the approach of buildings, insulation distances, especially in the area of ​​artificial structures, etc .; in addition, a minimum inclination of the strings must be ensured at extreme ambient temperatures, when noticeable longitudinal movements of the contact wire relative to the carrier cable can occur. For compensated suspensions, this is possible if the carrier cable and the contact wire are made of different materials.
To increase the service life of the contact inserts of current collectors, the contact wire is placed in a zigzag plan. There are various options for suspension of the carrier cable: in the same vertical planes as the contact wire (vertical suspension), along the axis of the track (half-oblique suspension), with zigzags opposite to the zigzags of the contact wire (oblique suspension). Vertical suspension has less wind resistance, oblique - the greatest, but it is the most difficult to install and maintain. On straight sections of the track, semi-oblique suspension is mainly used, on curved sections - vertical. In areas with particularly strong wind loads, a diamond-shaped suspension is widely used, in which two contact wires suspended from a common carrier cable are located at supports with opposite zigzags. In the middle parts of the spans, the wires are drawn to each other by rigid strips. In some suspensions, lateral stability is ensured by the use of two carrying cables, which form a kind of cable-stayed system in the horizontal plane.
Abroad, single chain suspensions are mainly used, including in high-speed sections - with spring wires, simple spaced support strings, as well as with carrier cables and contact wires with increased tension.

contact wire

The contact wire is the most important element of the catenary suspension, directly making contact with the EPS current collectors in the process of current collection. As a rule, one or two contact wires are used. Two wires are usually used when removing currents of more than 1000 A. On domestic railways. e. use contact wires with a cross-sectional area of ​​​​75, 100, 120, less often 150 mm2; abroad - from 65 to 194 mm2. The cross-sectional shape of the wire has undergone some changes; in the beginning. 20th century the section profile acquired a shape with two longitudinal grooves in the upper part - the head, which serve to fix the contact network fittings on the wire. In domestic practice, the dimensions of the head (Fig. 8.12) are the same for different cross-sectional areas; in other countries the dimensions of the head depend on the cross-sectional area. In Russia, the contact wire is marked with letters and numbers indicating the material, profile and cross-sectional area in mm2 (for example, MF-150 - copper shaped, cross-sectional area 150 mm2).

In recent years, low-alloyed copper wires with additives of silver and tin, which increase the wear and heat resistance of the wire, have become widespread. The best indicators in terms of wear resistance (2-2.5 times higher than that of copper wire) are bronze copper-cadmium wires, but they are more expensive than copper wires, and their electrical resistance is higher. The expediency of using one or another wire is determined by a technical and economic calculation, taking into account specific operating conditions, in particular, when solving issues of ensuring current collection on high-speed lines. Of particular interest is a bimetallic wire (Fig. 8.13), suspended mainly on the receiving and departure tracks of stations, as well as a combined steel-aluminum wire (the contact part is steel, Fig. 8.14).

During operation, wear of the contact wires occurs during current collection. There are electrical and mechanical components of wear. To prevent wire breakage due to an increase in tensile stresses, the maximum wear value is normalized (for example, for a wire with a cross-sectional area of ​​​​100 mm, the allowable wear is 35 mm2); as the wear of the wire increases, its tension is periodically reduced.
During operation, a break in the contact wire can occur as a result of the thermal effect of an electric current (arc) in the zone of interaction with another device, i.e., as a result of a wire burnout. Most often, burnouts of the contact wire occur in the following cases: over current collectors of a fixed EPS due to a short circuit in its high-voltage circuits; when raising or lowering the pantograph due to the flow of load current or short circuit through an electric arc; with an increase in contact resistance between the wire and the contact inserts of the current collector; the presence of ice; closing by the skid of the current collector of different potential branches of the insulating interface of the anchor sections, etc.
The main measures to prevent wire burnouts are: increasing the sensitivity and speed of protection against short-circuit currents; the use of a lock on the EPS that prevents the pantograph from lifting under load and forcibly turns it off when lowered; equipment of insulating interfaces of anchor sections with protective devices that contribute to extinguishing the arc in the zone of its possible occurrence; timely measures to prevent ice deposits on wires, etc.

carrier cable

Carrying cable - a wire of a chain suspension attached to the supporting devices of the contact network. A contact wire is suspended from the carrier cable with the help of strings - directly or through an auxiliary cable.
On domestic railways on the main tracks of lines electrified at direct current, copper wire with a cross-sectional area of ​​\u200b\u200b120 mm2 is mainly used as a carrier cable, and steel-copper wire (70 and 95 mm2) is used on the side tracks of stations. Abroad, on AC lines, bronze and steel cables with a cross section of 50 to 210 mm2 are also used. The tension of the cable in a semi-compensated contact suspension varies depending on the ambient temperature in the range from 9 to 20 kN, in a compensated suspension, depending on the brand of wire - in the range of 10-30 kN.

String

A string is an element of a chain contact suspension, with the help of which one of its wires (usually a contact one) is suspended from another - a carrier cable.
By design, they distinguish: link strings, composed of two or more spherically connected links of rigid wire; flexible strings made of flexible wire or nylon rope; rigid - in the form of spacers between the wires, used much less frequently; loop - from a wire or a metal strip freely suspended on the upper wire and rigidly or hingedly fixed in the string clamps of the lower (usually contact); sliding strings attached to one of the wires and sliding along the other.
On domestic railways e. the most widely used link strings made of bimetallic steel-copper wire with a diameter of 4 mm. Their disadvantage is electrical and mechanical wear in the joints of individual links. In the calculations, these strings are not considered as conductive. Flexible strings made of copper or bronze stranded wire, rigidly attached to string clamps and acting as electrical connectors distributed along the contact suspension and not forming significant concentrated masses on the contact wire, which is typical for typical transverse electrical connectors used in link and other non-conductive strings. Sometimes non-conductive contact suspension strings made of nylon rope are used, for fastening of which transverse electrical connectors are required.
Sliding strings capable of moving along one of the wires are used in semi-compensated catenary contact hangers with a low structural height, when installing sectional insulators, at anchoring points of a carrier cable on artificial structures with limited vertical dimensions, and in other special conditions.
Rigid strings are usually installed only on the overhead arrows of the contact network, where they act as a limiter for lifting the contact wire of one suspension relative to the wire of another.

reinforcing wire

Reinforcing wire - a wire electrically connected to the contact suspension, which serves to reduce the overall electrical resistance of the contact network. As a rule, the reinforcing wire is suspended on brackets on the field side of the support, less often - above the supports or on consoles near the carrier cable. The reinforcing wire is used in sections of direct and alternating current. The decrease in the inductive resistance of the AC contact network depends not only on the characteristics of the wire itself, but also on its placement relative to the wires of the contact suspension.
The use of a reinforcing wire is provided at the design stage; as a rule, one or more stranded wires of type A-185 are used.

electrical connector

Electrical connector - a piece of wire with conductive fittings, designed for electrical connection of wires of the contact network. There are transverse, longitudinal and bypass connectors. They are made of uninsulated wires so that they do not interfere with the longitudinal movements of the wires of contact suspensions.
Cross connectors are installed for parallel connection of all wires of the contact network of the same path (including reinforcing ones) and at stations for contact suspensions of several parallel paths included in one section. Cross connectors are mounted along the path at distances depending on the type of current and the share of the cross section of the contact wires in the total cross section of the wires of the contact network, as well as on the operating modes of the EPS on specific traction arms. In addition, at the stations, the connectors are placed in the places of starting and acceleration of the EPS.
Longitudinal connectors are installed on overhead arrows between all wires of contact suspensions that form this arrow, at the junctions of the anchor sections - on both sides with non-insulating mates and on the one hand with insulating mates and in other places.
Bypass connectors are used in cases where it is required to replenish the interrupted or reduced cross-section of the contact suspension due to the presence of intermediate anchorings of reinforcing wires or when insulators are included in the supporting cable for passing through an artificial structure.

Contact network fittings

Contact network fittings - clamps and parts for connecting the wires of the contact suspension to each other, with supporting devices and supports. Armature (Fig. 8.15) is divided into tension (butt, end clamps, etc.), suspension (string clamps, saddles, etc.), fixing (fixing clamps, holders, lugs, etc.), conductive, mechanically lightly loaded (clamps supply, connecting and transitional - from copper to aluminum wires). The products that make up the fittings, in accordance with their purpose and production technology (casting, cold and hot stamping, pressing, etc.), are made of ductile iron, steel, copper and aluminum alloys, and plastics. The technical parameters of the fittings are regulated by regulatory documents.