Repair of railway contact network. Organization of contact network maintenance
The contact network is integral part power supply devices intended for power supply to train traction, signaling devices and other railway consumers.
To the main electrical devices power supply also includes traction substations, including mobile ones, transformer substations, distribution and supply points of electrical energy, power plants, including mobile ones; sectioning posts and points parallel connection; power supply lines, including longitudinal, i.e. located along the railway, overhead and cable distribution networks; external lighting of railway stations, stopping points, crossings and other objects; telemechanics system for power supply devices.
Maintenance of all these devices is entrusted to power supply distance(EC) is a structural subdivision of the railway department (NOD) (manufacturing enterprise in railway transport). Technical management of the power supply economy is carried out in the Department of Mainline Railway Networks (MRT) of JSC NC KTZ by the Department of Electrification and Power Supply (CE), in the Road Departments (N) - by Electricity Supply Services (ES).
The service boundaries of power supply distances are usually located within railway departments. For large departments on electrified freight-intensive routes and with a large volume of power supply work, two or more power supply distances are organized. There are about 300 of them on railways. Depending on the volume of work, power supply distances are divided into four groups.
When the number of points is over 70, group I is established, from 40 to 70 - group II, from 15 to 40 - group III and up to 15 - group IV.
The power supply distance in its activities is guided by the Law of the Republic of Kazakhstan on state enterprises (associations), taking into account the specific application to railway transport, the Law of the Republic of Kazakhstan on labor collectives and increasing their role in the management of enterprises, institutions, organizations.
Administrative and technical management is carried out by the power supply department headed by the chief, deputy and chief engineer, there is a production and technical group and an accounting department.
Round-the-clock operational management is carried out by an energy dispatch team (EDT), serving one or more dispatch circles within the distance.
The main production workshops include areas contact network(EChK), traction substations (EChE) and areas electrical networks(EPS), to auxiliary ones - electrical installation and operational production area (EPU), mechanical workshops (EMS), warehouse facilities.
Contact network areas carry out maintenance and repair of the contact network, as well as overhead longitudinal power supply lines with voltages of 6 and 10 kV, feeding signaling devices and other consumers, and lines with voltages up to 400 V at hauls and intermediate stations (except for large junctions), passing along the supports of the contact network and on separate ones.
The service boundaries of the contact network areas are determined by the operational length of the section and the expanded or reduced length of the contact network (electrified tracks).
Operating length- this is the distance of the serviced electrified section between the boundaries, regardless of the number of tracks on the common roadbed.
Unfolded length is determined by summing the lengths of all electrified tracks, stages and stations within the service limits.
Given length is determined as follows: to the operational length is added the length taken as 0.9 km per 1 km of each main electrified track in excess of the first at hauls and stations and all electrified at connecting stations and taken as 0.75 km per 1 km of electrified station tracks at other stations.
The operational length of an electrified line under the jurisdiction of one contact network district is usually about 50 km; the duty station is located in the middle of the serviced area. At large junction stations with a large development of electrified tracks and when the duty station is located at one end of the contact network area, the operational service length, depending on the developed length of the electrified tracks, is up to 35 km.
The duty station of the contact network area serves to accommodate personnel, workshops, garage and storage facilities. On its territory there is a building, a loading platform and other auxiliary devices. The duty station is placed so that quick and unhindered departure of the recovery railcar (trolley) and auto-vacation is ensured.
They build duty stations for the contact network areas according to standard designs (Fig. 208 and 209). In some cases, duty stations are located on a common territory and in the same building with traction substations or power supply offices. At large stations within the districts, additional duty stations will be organized.
For prompt negotiations between personnel and the energy dispatcher and employees of other services, duty stations have equipment for intercom and energy dispatch telephone communication. For negotiations directly from the work site, portable field telephones are used, connected to the wires of energy dispatch communication lines, long-distance communication devices, which are located in cabinets near the automatic blocking signals, or radio stations, which are available on railcars (trains) and auto-flights.
The length of the contact network area is determined by the expanded length of the contact network. The expanded length of the contact network for the region is usually taken on double-track and multi-track lines up to 150 km, on single-track lines up to 80 km and at large junction stations up to 200 km. The volume of work of the contact network district is determined by points depending on the indicators, and the number of points determines the complexity group of the district for remuneration of engineers.
The total number of points is calculated according to the established standard. When the number of points is over 4.5, group I is established, from 1.5 to 4.5 - group II and up to 1.5 - III.
Contact network areas serving permanent and permanent connection stations alternating current, belong to group I. Contact network areas have an established staff of electricians headed by a supervisor and an electrician. The staff is calculated based on the norms for labor costs for maintenance and routine repairs of the contact network. Costs are 0.12-0.18 people. per 1 km of the deployed length of the contact network.
To quickly eliminate damage to the contact network, on-duty personnel are provided, the number of which is determined based on the average requirement of 4.2 people. with round-the-clock duty at the workplace and 2.1 people. - when on duty at home. The number and composition of repair teams depend on the length of the contact network served by the area. The approximate staff of a contact network area with one or two repair teams is as follows:
The composition of the areas where, in addition to the contact network at the stages and intermediate stations, personnel service high-voltage lines, automatic blocking power supply devices, longitudinal power supply lines, lighting and other low-voltage lines located within the area, also includes an electrician and a group of electricians for their maintenance (3 -5 people).
In areas of the contact network, operational and technical documentation is maintained and regularly adjusted in accordance with the requirements of the Rules for the maintenance and repair of the contact network of electrified railways.
In the area of the contact network, in addition, in the power supply distance and the restoration train for major restoration work, there is an irreducible supply of materials, equipment and fixtures according to the list approved by the Ministry of Railways.
Areas of the contact network have an installation and restoration motor carriage or railcar with an insulated tower, a railway platform and a restoration motor vehicle.
The ADM installation and restoration railcar is designed to perform installation, repair and emergency restoration work on the contact network. The carriage is propelled by a diesel engine; the speed of the carriage is up to 100 km/h. It has a lifting working platform with a lifting height of up to 7 m, isolated from grounded parts, which makes it possible to perform work from it on a live contact network. The platforms have a fence in the form of folding railings. The platform is controlled remotely, its rotation angle is 210° with the cantilever part being moved from the track axis to a distance of 6.8 m. The cabin is equipped with a jib crane with a lifting capacity of up to 3 tons with a boom reach of up to 8 m, which is used for installing contact network supports, loading and unloading materials. The railcar is equipped with a generator with a power of 50 kW and a voltage of 400 V. The cabin of the railcar can carry 11 people. The railcar is equipped with a radio station for communication with the energy dispatcher. The supply of materials and parts is placed in special boxes on the platform of a railcar and a four-axle or special two-axle railway platform.
On the same basis, a DGKu cargo railcar was created, intended for shunting and loading and unloading operations with a crane with a lifting capacity of up to 3 tons and transportation of goods up to 6 tons. The previously produced AGM railcars with a crane lifting capacity of 1 ton and the ability to transport cargo up to 5 tons have the same purpose. t. Load-lifting cranes with a cantilever horizontal boom have a lifting height from the level of the rail head for the DGK U railcar of 4 m and the AGMu railcar of 3 m with a boom radius of up to 5.8 and 4.5 m, respectively.
The AGV installation and restoration railcar (Fig. 15.9) is driven by a diesel engine; the speed of the railcar is up to 80 km/h. Equipped with a 50 kW power generator. The working isolated platform with a hydraulic drive of the lifting mechanism has maximum height the rise from the rail head is 7.6 m and the reach from the track axis is 4 m. The platform rotates 90° in both directions. Enter the work site through two isolated neutral sites. The insulation of the pads is designed for voltages up to 35 kV. The work site and the contact network are illuminated at night by floodlights installed on the site.
Rice. 15.9. Assembly and restoration railcar AGV
The railcar has a crane with a lifting capacity of 3 tons with a boom that rotates 180°. The drive for turning and lifting the boom is also hydraulic. A railcar crane can be used to install reinforced concrete supports.
The DMS installation and restoration trolley (Fig. 15.10) is driven by a ZIL-130 engine, the speed of the trolley is up to 80 km/h. The assembly tower consists of a guide shaft and a lifting cage. The cage is raised and lowered by a screw driven through a worm gearbox from the motor of the railcar.
Rice. 15.10. DMS installation and restoration trolley
For access to the work site from the field, all-terrain vehicles based on the GAZ-66 AK type vehicle are used. It has two compartments: front - passenger for 7 people. and the rear one is cargo for transporting 500 kg of cargo. There are also pilot trucks based on GAZ-52, GAZ-53, ZIL-164, ZIL-157 and others.
To deliver crews in off-road conditions (wetlands, water obstacles), they use auto-batches - all-terrain vehicles GTT or GAZ-47 on caterpillar tracks. There are AMP-3 assembly station trucks based on UAZ vehicles for transporting 4 people. and load 320 kg.
Work on the energized contact network without closing the stages for train traffic is carried out from insulating removable towers (Fig. 15.11) available at duty points, at stations, separate points and stages near boarding platforms at the rate of one tower per 4-5 km of operational length . They are manufactured in two versions: for work under voltage on the contact network direct current 3.3 kV and AC 27.5 kV.
Rice. 15.11. Insulating removable tower
In an insulating removable staircase tower 2 and braces 3 made of dry wood impregnated with transformer oil or fiberglass. Ramu 1 made from steel pipes.
Ladders and braces of wooden insulating removable towers for working in areas of alternating current are made of pine wood improved quality, impregnated with a solution of hydrophobic organosilicon liquid or GKZh-94. To enhance the insulation of rack towers under the platform 4 supplemented with insulating inserts made of fiberglass or mica getinax, coated with varnish. Each tower is equipped with two shunt rods 5 and a 3 m long suspended ladder for working on a supporting cable.
The mass of the removable insulating tower for direct current sections is no more than 133 kg and alternating current - 143 kg.
To climb the contact network supports, they use attached and hinged wooden ladders 9 and 6.5 m long - weighing 38 and 24 kg, respectively, or collapsible metal LR-1, consisting of six links 1.55 m long each, successively increased to the required height. Staircase width 0.5 m, weight 48 kg.
A set of devices for transmitting electricity from traction substations to EPS through current collectors. The contact network is part of the traction network and for electrified rail transport usually serves as its phase (for alternating current) or pole (for direct current); the other phase (or pole) is the rail network.
The contact network can be made with a contact rail or a catenary. Running rails were first used to transmit electricity to a moving carriage in 1876 by Russian engineer F.A. Pirotsky. The first catenary appeared in 1881 in Germany.
The main elements of a contact network with a catenary suspension (often called overhead) are contact network wires (contact wire, supporting cable, reinforcing wire, etc.), supports, supporting devices (consoles, 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 - mainline, including high-speed, railway, tram and quarry transport, underground mine transport, etc.; by the type of current and rated voltage of the EPS powered from the contact network; on the placement of the contact suspension relative to the axis of the rail track - for the central (mainline railway transport) or lateral (industrial transport) current collection; by types of contact suspension - contact networks with simple, chain or special suspension; according to the features of implementation - contact networks of stages, stations, for arts, structures.
Unlike other power supply devices, the contact network does not have a reserve. Therefore, increased requirements are placed on the reliability of the contact network, taking into account which the 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 the contact network wires is usually carried out when designing a traction power supply system. All other issues are resolved using the contact theory network - independent scientific discipline, the formation of which was largely facilitated by the work of Sov. scientist I.I. Vlasov. The design issues of the overhead contact network are based on: selection of the number and grades of its wires in accordance with the results of calculations of the traction power supply system, as well as traction calculations, selection of the type of contact suspension in accordance with the maximum speed of movement of the EPS and other current collection conditions; determination of the span length (mainly based on 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 and structures; placement of supports and drawing up plans for the contact network of stations and stages with coordination of zigzags of wires and taking into account the implementation of air switches and elements of sectioning the contact network (insulating connections of anchor sections, sectional insulators and disconnectors). When choosing methods of construction and installation of the contact network during the electrification of railways, we strive to ensure that they have the least possible impact on the transportation process with unconditional provision High Quality works
The main production enterprises for the construction of overhead contact networks 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 for ensuring the specified high level reliability of the contact network at the lowest labor and material costs, labor safety for workers in the contact network areas, and possibly less impact on the organization of train traffic. Production, acceptance for the operation of the contact network is the distance of power supply.
The main dimensions (see figure) characterizing the placement of the contact network relative to other posts and railway devices. d., - height H of hanging 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 others permanent devices main railways: Pcs - overhead wires; O - contact network support; And - insulators.
distance A from live parts to grounded parts of structures and rolling stock; distance Г from the axis of the outer track 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. F.-b. Contact network supports and metal support foundations are made taking into account the electrocorrosive effect of stray currents on their fittings. Increasing the service life of the contact wire is achieved, as a rule, by using carbon contact inserts on current collectors.
At maintenance contact network on domestic railways. without stress relief, insulating removable towers and assembly railcars are used. The list of work performed under voltage has been expanded thanks to the use of double insulation on flexible crossbars, wire anchors and other elements of the contact network. Many control operations are carried out by means of their diagnostics, which are equipped in laboratory cars. The switching efficiency of sectional contact network disconnectors has increased significantly thanks to the use of telecontrol. The equipment of power supply distances with specialized mechanisms and machines for repairing contact networks (for example, for digging pits and installing supports) is increasing.
Increasing the reliability of contact networks is facilitated by the use of ice melting methods developed in our country, including without interruption of train traffic, electrical repellent protection, wind-resistant diamond-shaped contact suspension, etc. To determine the number of areas of contact networks and the boundaries of service areas, 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 specified limits. On domestic railways, the developed length of electrified tracks is an accounting indicator for regions of the electrical system, power supply distances, road sections, and is more than 2.5 times greater than the operational length. Determination of the need for materials for the repair and maintenance needs of contact networks is carried out along its expanded length.
A contact network is a special power transmission line that serves to supply electrical energy to electric rolling stock. Its specific feature is that it must provide current collection to moving electric locomotives. The second specific feature of the contact network is that it cannot have a reserve. This places increased demands on the reliability of its operation.
The contact network consists of a catenary track suspension, contact network supports, and devices supporting and fixing the contact network wires in space. In turn, the contact suspension is formed by a system of wires - a support cable and contact wires. For a DC traction system there are usually two contact wires in the hanger and one for an AC traction system. In Fig. Figure 6 shows a general view of the contact network.
The traction substation supplies electric rolling stock with electricity through the contact network. Depending on the connection of the overhead contact network with traction substations and between contact suspensions of other tracks of a multi-track section within the boundaries of a separate inter-substation zone, the following schemes are distinguished: a) separate two-way; 
Rice. 1. General view of the contact network
b) nodal; c) parallel. 
A) 
V)
Rice. 2. Basic power supply circuits for track overhead contacts a) – separate; b) – nodal; c) – parallel. PPS - points for parallel connection of contact suspensions of different tracks; PS – sectioning post; TP – traction substation
Separate two-way circuit - a catenary power supply circuit in which energy is supplied to the contact network from both sides (adjacent traction substations operate in parallel on the traction network), but the contact pendants are not electrically connected to each other within the boundaries of the intersubstation zone. The scope of application of such a scheme is the power supply of sections of an electric railway with short intersubstation zones and relatively uniform power consumption in directions.
Nodal diagram - a diagram that differs from the previous one in the presence electrical communication between track suspensions. Such communication is carried out using so-called catenary network sectioning posts. The technical equipment of the contact network sectioning posts allows, if necessary, to eliminate not only the transverse connection between track suspensions, but also the longitudinal one, dividing the contact network within the boundaries of the intersubstation 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 for more efficient use of track contact networks for transmitting electrical energy to electric rolling stock, which provides significant energy savings with uneven power consumption across directions. Consequently, the scope of application of such a suspension is sections of an electric railway with extended inter-substation zones and significant unevenness of power consumption in directions.
Parallel circuit– a circuit that differs from a node circuit by a large number electrical components between track overhead contacts. It is used when there is even greater unevenness in electricity consumption along the tracks. This scheme is especially effective when driving heavy trains.
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Introduction
1. Power supply and sectioning of the contact network
2. Determination of the maximum permissible span lengths
3. Selection of supporting structures
3.1 Selection of supports
3.2 Selection of rigid cross members
3.3 Selecting consoles
3.4 Selecting fasteners
4. Installation plan of the contact network
5. Checking the condition, adjusting and repairing the surge suppressor
6. Safety precautions when performing work on the contact network
Literature
Initial data
INTRODUCTION
Railway transport is a vital component of the economic system of the Russian Federation.
The first steam railway in Russia appeared in 1834. It was built by serf craftsmen-nuggets Efim Cherepanov and his son Miron at the Ural Nizhny Tagil Metallurgical Plant. They also built two locomotives for this road.
In 1837, the first railway St. Petersburg - Tsarskoe Selo was opened.
The beginning of operation of the electrified main railways of Russia is considered to be August 29, 1929, when the first Russian electric train set off from the platform of the Yaroslavsky railway station along the Moscow-Mytishchi route. On October 1, 1929, electric trains began to operate on schedule.
The experience of the first years of operation of the Moscow-Mytishchi section convincingly demonstrated the advantages of electric traction over steam and contributed to the expansion of the electric railway network.
By 1941, 1,865 km of railways had been converted to electric traction. In 1946-1955, the transition from electrification was made individual areas to the electrification of entire directions. In 1958, the USSR took first place in the world in terms of the length of electrified lines (9.5 thousand kilometers), and the greatest increase was achieved in 1965, when 2268 km were electrified, amounting to 24.9 thousand km. The largest routes have been converted to electric traction: Moscow - Irkutsk (over 5 thousand km), Moscow-Gorky-Sverdlovsk (about 2 thousand km), as well as suburban sections of large cities and industrial centers. At the same time, about 45% of railway freight turnover was carried by electric traction.
In total, during the period from 1956 to 1991, about 50 thousand km of the most important highways and entire directions were converted to electric traction in the USSR. As a result of the introduction of electric traction on railways, the throughput and carrying capacity on single-track lines increased by 1.5-2 times, on double-track lines by 2-2.5 times; labor productivity increased 1.5 times, and in suburban traffic - more than 2 times; the cost of transportation decreased by 1.5-2 times.
The conversion of railway lines to electric traction made it possible to increase the weight standards of trains, sectional speeds, and the average daily mileage of locomotives. The stability of operation has increased, especially in areas with harsh climatic conditions. One of the important advantages of electric traction is the environmental factor.
Today, electric locomotives and electric trains are the main type of traction on Russian railways. The country still ranks first in the world in terms of network length: by the end of 2010, the total length of electrified sections reaches 44.5 thousand km, on which 84% of all transportation is carried out.
contact network repair adjustment
1 . POWER AND SECTIONATION OF THE CONTACT NETWORK
To ensure reliable operation and ease of maintenance, the contact network of the electrified section is sectioned with insulating couplings of anchor sections, neutral inserts, sectional insulators, sectional disconnectors and mortise insulators.
Longitudinal sectioning involves separating the contact network of the stages from the contact network of stations along each main track. Longitudinal sectioning is carried out by three-span insulating connections of anchor sections. Longitudinal sectional disconnectors (A, B, C, D) that shunt them are installed at the insulating junctions. These disconnectors have motor drives.
Longitudinal disconnectors at the insulating junctions of the neutral inserts serve to supply voltage to the neutral insert in the event of a stop of the electric rolling stock on it.
Transverse sectioning of the contact network between tracks is carried out by sectional insulators, transverse disconnectors, as well as mortise insulators in the fixing cables of the crossbars and in the non-working branches of the contact suspensions crossing the suspensions of different sections. Sectional insulators are installed in contact suspensions of station tracks adjacent to the main ones (at ramps).
The sectioning and power supply diagram of the station and adjacent sections is shown in Figure 1.1.
Transverse disconnectors connecting contact suspensions of different sections of the station are designated by the letter P. They can have both manual (P12) and motor (P24) drives. The connection of contact suspensions of tracks where work is carried out near the contact network is carried out using sectional disconnectors with manual drives and grounding knives; They are designated by the letter Z (Z1, Z2).
The contact network is powered from traction substations by supply lines (feeders), usually overhead. Supply line disconnectors are designated by the letter F (F1, F2, F3, F4, F5). On double-track DC sections for the contact network of each of the main tracks of the station and the sections adjacent to the station, as well as for the contact network of the station, independent supply lines are designed, which are connected to traction substations through linear disconnectors with a motor drive (F1, F2, F3, F4 , F5). The DC power lines are connected to the contact network:
without disconnectors, if the length of the overhead supply lines is L<150 м;
through line disconnectors with manual drives, if the length of the supply lines is within 150 m through linear disconnectors with motor drives, if the length of the supply lines is L>750 m (F11, F22, F42, F51). Table 1.1 - Symbols of the power supply circuit Name Designation Single-pole disconnector with manual drive: a) normally turned on b) normally disabled Manual disconnector with grounding blade a) normally turned on b) normally disabled Single-pole disconnector with electric motor drive a) normally turned on b) normally disabled Mortise insulator or insulator garland Sectional insulator Interface insulating anchor sections 2
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DETERMINING THE MAXIMUM ALLOWABLESPAN LENGTH The number of supports and supporting structures and, consequently, the construction cost of the contact network depends on the length of the spans between the supports. In this regard, for economic reasons, span lengths should be taken as large as possible. However, the greatest horizontal deviation of the contact wires from the axis of the pantograph under the influence of wind depends on the span length. This value should not exceed the permissible values: on straight sections the largest horizontal deviation should not exceed 0.5 meters, on curved sections of the track 0.45 meters. The maximum permissible span lengths between supports are determined taking into account the type of suspension, grades, sections and tension of wires, radius of curves, design climatic conditions and operating conditions for two design modes - maximum wind and wind with ice. The smaller of the two values is accepted for design. The maximum permissible span lengths for the most common types of suspensions are given in nomograms. The span length for intermediate values at maximum wind speed without ice and with ice with wind, depending on the wind speed and the thickness of the ice wall, is determined on nomograms by linear interpolation (Figure 2.1). To determine the length of spans and deflections of wires under the influence of wind and when ice is combined with wind, wind speed and ice wall thickness are taken from long-term observations of maximum wind speeds and ice wall thickness with a repeatability of once every 10 years. In this case, it is necessary to take into account the nature of the underlying surface and the height of the embankment in individual areas in accordance with the design standards for the overhead contact network. The maximum permissible span length must be obtained by calculating wind deviations, subject to the following conditions: b to max b to additional Terrain features are taken into account by correction factors for wind speed: And to the thickness of the ice wall: Where is the standard wind speed standard wind speed during icy conditions standard ice wall thickness wind speed correction factor correction factor to ice wall thickness The value of the coefficient, depending on the nature of the terrain, is taken according to table 2.1 Table 2.1 Value of wind and ice coefficients We determine the wind speed taking into account the terrain using formula (1) in the maximum wind mode and formula (2) in case of ice with wind. at the station in maximum wind mode: at the station in icy conditions with wind: on the stretch in maximum wind mode: on a stretch in icy conditions with wind: on an embankment in maximum wind mode: on an embankment in icy conditions with wind: Using formula (3) we determine the thickness of the ice wall at the station on the stretch on the embankment We summarize the obtained data in table 2.2 The maximum span of the catenary system should not exceed 70 meters; in places exposed to the wind and on embankments with a height of 5 to 10 meters in wooded areas - 60 meters; on embankments from 5 to 10 meters in open areas, in floodplains and above ravines - 50 meters; on embankments, overpasses and bridges at a height of more than 10 meters above open areas or above trees in wooded areas - 40 meters. The maximum length of the catenary span in curved sections of the track that are not protected from the wind should not exceed: for a curve radius of 700 meters - 45 meters; a radius of 500 meters - 40 meters, a radius of 300 meters - 35 meters. Adjacent spans of a semi-compensated suspension should not differ by more than 25 percent from the length of the larger span. The length of transition spans of insulating joints should be reduced by 25 percent compared to intermediate spans calculated for a given location. The length of spans with medium anchorage of the contact wire is reduced by 10 percent compared to the calculated one 3
.
SELECTION OF SUPPORTING STRUCTURES The choice of supporting devices when designing a contact network consists of linking standard designs to specific installation conditions. Supporting reinforced concrete and metal devices are made based on the permissible design loads established by the Catenary Network Design Standards. Structural calculations are carried out taking into account the main and emergency modes. 3.1
Selection of supports Supports are classified by purpose, by the direction of application of the load, by the design of the supporting structures, by the material from which they are made, and by the method of fixation in the ground. Depending on the purpose, contact network supports are distinguished: intermediate, transitional, anchor and fixing. Fixing supports are divided into: cantilever supports used to attach one, two or more tracks to the catenary console; supports of rigid crossbars, used for fastening contact suspensions of electrified tracks on the crossbar of rigid crossbars; supports of flexible crossbars, used for fastening contact suspensions on electrified tracks covered by the crossbar. Based on the material from which the supports are made, a distinction is made between metal and reinforced concrete. Depending on the method of fixation in the ground: separate and non-separate (foundationless), including a glass connection. Metal supports can be directional or non-directional. In order to save metal, the supports of flexible crossbars are usually directional. Reinforced concrete supports are most widespread. They are used as intermediate, transitional and anchor cantilever supports, as well as fixing, feeder, special supports and racks of rigid crossbars. The use of reinforced concrete supports with prestressed centrifuged reinforcement reduces the consumption of metal for the manufacture of supports. However, installing reinforced concrete supports is more difficult than metal ones, since they are heavier and more fragile. The main parameters and technical requirements for reinforced concrete racks for overhead contact line supports are determined by GOST 19330-90. Reinforced concrete supports of the contact network are made of high-density and strength concrete. When making supports, the concrete mixture is compacted by centrifugation or vibration with prestressing reinforcement. Based on the nature of the placement of non-stressed parts, supports are divided into two types: with non-stressed reinforcement only in the underground part (SO) and along the entire length (SS). The marking of racks of reinforced concrete supports of the contact network consists of alphanumeric groups separated by a dash. The first group is alphabetic, indicating the brand of supports: C - rack with stressed wire reinforcement; SO - rack with stressed wire reinforcement and non-stressed rod reinforcement of the foundation part; SS post with stressed wire reinforcement and non-stressed rod reinforcement along the entire length. The second is numerical - its length in decimeters and wall thickness in centimeters. The third - numerical - number according to the bearing capacity in kN m (standard bending moment 1 - 40 kN m, 2 - 60 kN m, 3 - 80 kN m, 4 - 100 kN m). For example: SS 136, 6 - 3 - special stand, 13.6 meters high, support wall thickness 6 centimeters, third load-bearing capacity - standard bending moment 79 kN m. On newly electrified lines, standard reinforced concrete conical supports of the SS type are used (Table 3.1.1) Table 3.1.1 Main characteristics of supports type SS The selection of a cantilever support begins with determining the load and bending moments at the base of intermediate supports installed on the outer and inner sides of the curve of the smallest given radius in all design modes and in the most unfavorable wind directions (Figure 3.1.1). Calculation and selection of standard supports Nominal wire tension: Support cable N N 1765 daN Contact wire N to 1960 daN We accept for installation type SS supports with a length of 13.6 m, without foundation Support dimensions on a straight section…………….3.1 m Support dimensions on a curved section Internal………...3.5 m External……………3.2 m Determination of standard loads Linear loads on the supporting cable, on contact wires, wind loads at speed are determined by the appropriate calculation and entered into Table 3.1.2 1 kG = daN = 10 N Figure 3.1.1 Determination of the load on the support Horizontal load from wind pressure on the support cable, daN; the same for the contact cable, daN; the same, on a support, daN; horizontal load from a break in the supporting cable on the curve, daN; the same, from a break in the contact wire, daN; vertical load from the weight of the catenary, daN; support height, m; height of the points of application of horizontal forces relative to the base of the supports, m; console weight arm, m; a - zigzag contact wire, m; G - dimensions of the support, m; diameter of the support at the level of the rail head, m. Table 3.1.2 Weather loads on wires C X - aerodynamic coefficient. We accept 1.85 We take the weight of the console to be 60 daN, with ice 100 daN. Using Table 3.1.2, we determine the standard loads on supports under the required design conditions for given sections of the route and span lengths. The load from the weight of the contact suspension is determined by the formula
Straight The load from wind pressure on the catenary wires is determined by the formulas On the supporting cable On the contact wire) Loads from changing the direction of wires On a curved section we calculate using the formulas For support cable For contact wire Where is the span length radius of curvature. N - tension of an uncompensated support cable with changes in air temperature and load from wind and ice. Changes can be made: in case of ice and wind N g = 75% of N max: N g = 0.75 N max. N g = 0.75 1765 = 1323.75 daN At maximum wind N in = 70% of N max: N in = 0.7 N max. N in = 0.7 1765 = 1235.5 daN The change in direction of contact wires on straight sections of the track during zigzags is determined by the formula a - zigzag contact wire, a = 0.3 Loads from wind pressure on supports are determined by the formulas where is the diametrical cross-sectional area of the support (surface area i on which the wind acts) S op = av + an/ 2 h op = 3.5 m C X - aerodynamic drag coefficient, assumed for cone-shaped elements of 0.7 V r - estimated wind speed m/s The calculation results are shown in Table 3.1.3. Table 3.1.3 Support loads Symbol Dimension Wind max. Wind max. Suspension weight Loads from changing the direction of wires on a curved section tension of an uncompensated support cable with changes in air temperature and load Changing the direction of contact wires on straight sections of the track during zigzags R K from zig Wind pressure on the support We will select supports separately for each of the given types of supports. We will determine the bending moments for intermediate supports relative to the level of the conventional foundation edge. The calculated wind direction for supports on straight sections of the path and on the outer side of the curve will be taken from the support to the path, for support on the inside of the curve - from the path to the support. Bending moments relative to the level of the conventional foundation edge are determined by the formula M 0 = G p Z p + G Kp Z Kp + P N h N + P K h K + P op +1/2h op; R K = R K in + R K zig; Z p =G + S d op = G + 0.2; 1/2h op = 9.6: 2 = 4.8; G straight = 3.1; G int cr = 3.45; G ext cr = 3.15; Z p =3.1 + 0.2 =3.3; Z p = 3.45 + 0.2 = 3.65; Z p = 3.15 + 0.2 = 3.35; R K g = 48.3 + 33.6 = 81.9 R K in = 58.8 + 33.6 = 92.4 Selection of intermediate support on a straight section of track. Standard bending moment relative to UOF: in icy conditions with wind: We select an intermediate support on the inside of the curve using the formula in icy conditions with wind at maximum wind mode Selecting an intermediate support on the outside of the curve Standard bending moment relative to the UOF level: in icy conditions with wind at maximum wind mode We summarize the calculations in table 3.1.4 Table 3.1.4 Design bending moments Based on the calculation, in accordance with the maximum bending moment, we select support SS-136.6-2 Table 3.1.5 Standard bending moments of support СС-136,6-2 3.2
Selection of rigid crossbars Rigid crossbars (crossbars) are metal trusses with parallel chords and a diagonal triangular lattice with spacers at each node. Depending on the number of tracks covered by rigid crossbars, they can have a length from 16.1 to 44.2 meters and are assembled from two, three, or four blocks. The maximum number of paths covered by a rigid crossbar is eight paths. Rigid cross members are designated by the letter “P” and numbers. The first numbers determine the load-bearing capacity of the cross member in m, the second the design span. Rigid crossbars with a design length of more than 29.1 meters, on which floodlights are installed to illuminate station tracks, are designated by the letters “OP”, where “O” means with lighting. Basic data of typical crossbars are given in Table 3.2.1 Table 3.2.1 Basic data of typical rigid crossbars 3.3 Selecting consoles Consoles are designed for fastening supporting cables and contact wires of the network in a certain position relative to the axis of the track, the level of the rail head, the ground and other structures. Consoles are classified: by the number of overlapped tracks: single-track and double-track; in shape: straight, inclined and curved; according to the presence of insulation: uninsulated and insulated. Straight consoles installed at an angle to the support are called inclined, while straight consoles are called horizontal. Curved consoles have a horizontal and inclined part in relation to the support. The console is attached (Figure 3.3.2) to the support in the “console heel” (5) and is held in place using a rod (1.3). The “heel” of the console can be rotary or fixed. Consoles that have rotary heel and thrust units are called rotary. Depending on the direction of application of loads, the cantilever rods can be tensile (1) or compressed (3). The console rod adjusts the height of the console. The extended rod (1) is adjusted using the adjustment plate (2), the compressed rod (3) is adjusted using the adjustment pipe (4). When designating consoles, the following symbols are used: Letters - I - isolated; T - tubular; C - with compressed traction; P - with stretched rod; N - inclined; G - horizontal straight line; P - straight, installed on supports outside the railway platforms; F - with a locking stand at the end; D - two ways; P - transitional with reinforced stand. Numbers: Roman numeral - dimensions and load capacity; Arabic numeral - channel number. For example, NS - I - 6.5 non-insulated inclined single-track console with compressed traction, with support dimensions of 3.1-3.5 meters, with channel number 6.5; NR - II - 5 - non-insulated inclined single-track console with stretched traction, with a dimension of 3.3 - 3.5 meters, with channel number 5. Figure 3.3.2 - Non-insulated inclined single-track console. The choice of console type is determined by the design decision. As a rule, a single-track console is used, which eliminates the mechanical connection of catenary suspensions with adjacent tracks. Currently, in areas of direct and alternating current, non-insulated and insulated straight inclined single-track consoles are used in new designs. The choice of consoles is carried out taking into account climatic data: ice thickness and wind speed; type of current, location. 3.4 Selecting fasteners Clamps are designed to hold wires in a horizontal plane in a certain position relative to the axis of the track (pantograph) in order to ensure the required elasticity of the contact suspension and reliable current collection. In the symbols of the clamps, letters and numbers indicate the design features and scope of their application: the voltage in the contact network for which they are intended; geometric dimensions. Clamps are installed on the working branch of the contact wire: straight articulated (FP, UFP) (Figure 3.4.1), reverse articulated (FO, UFO) (Figure 3.4.2) and flexible (FG) Figure 3.4.1 - Lock type FP-3 Figure 3.4.2 - UFO type retainer The clamps must ensure reliable fastening of the contact wires in the required position relative to the track axis, the ability to regulate the zigzag, vertical movement of the contact wires when pressed by the pantograph, movement of the wires when the temperature changes, and smooth current collection without shocks or sparks at the set speed. On the main tracks of haulage and receiving stations and other tracks where the speed exceeds 50 kilometers per hour, articulated clamps are installed, which consist of a main clamp rod (1), an additional clamp (2), which must always be stretched (its length is not less than 1200 mm), and the retaining post (3). Articulated clamps are direct, for negative zigzags, and reverse, for positive ones. Table 3.4.1 Types of fasteners Designation Decoding Installation location Straight clamp, voltage 3 kV Roman numeral - geometric dimensions Negative zigzags Reverse clamp Plus zigzags Anchor branch clamp On transition supports Reinforced On turns (curved section) Diamond Suspension Retainer Windy areas FG (direct only) UFG Flexible retainer On the outside of the curve Reinforced double 3 kV Reinforced double return at 3 kV With a radius of curvature less than 400m Air arrow lock Air arrows on the wires 4.
CONTACT NETWORK INSTALLATION PLAN The station plan is drawn on a scale of 1:1000. The layout of supports at the station should begin with marking the places where it is necessary to provide devices for fixing contact wires. Such places are all turnouts over which air switches must be mounted, and all places where the contact wire must change its direction (for example, on turnout curves of the outer tracks of a station). On the arrow curves of the outer tracks of the station, it is advisable to select the places for fixing the contact wires in the middle of the curves - at the point of intersection of the axes of the ramps and the outer tracks. It is allowed, if necessary, to move the support from this point by 1-5 m in any direction. In each place where fixation of contact wires is necessary, the proposed support should be shown on the plan and, having determined its station picket, i.e. distance from the axis of the passenger building, indicate it. Arrangement of supports in the necks of the station: The placement of supports at the station should begin with the necks, where the largest number of places for fixing contact wires is concentrated. From the identified necessary fixation places, a choice is made of those places where it is rational to install load-bearing supports, i.e. supports with consoles or cross members. Non-fixed switches can be made only on side tracks if it is possible to fasten wires on supporting structures located close to (up to 20 m) from the switch, ensuring the installation of the switch without clamps within the switch. The span length between load-bearing supports should not exceed the maximum design value. The span length between the load-bearing supports must be at least 30-35 m. The difference in the lengths of adjacent spans of a semi-compensated suspension should be no more than 25% of the length of the larger one (for example, 60 and 45 m). You need to place zigzags at the supports that fix the arrows. Arrangement of supports in the middle part of the station: between the supports installed to fix the arrows and arrow curves in both necks of the station, there remains a distance that should be divided into spans close to the maximum design ones, aiming to install the minimum number of supports. In this case, the following conditions are met: air gunners that may meet in the middle of the station tend to be fixed on the planned rigid crossbars; location of supports: in passenger buildings, supports should not be located against the doors or interfere with passengers; rigid cross members cannot pass over warehouses; supports, as a rule, should be positioned on loading platforms and container platforms so as not to interfere with the operation of forklifts, gantry cranes, etc.; individual parks or groups of tracks are placed on separate crossbars or cantilever supports. Arrangement of supports at the ends of the station. According to the established sectioning scheme for the contact network, longitudinal sectioning must be performed at the junctions of the stages with stations. When laying out supports for insulating joints, it is necessary to take into account that the length of the spans between the transition supports is reduced; on straight sections of the track it should be 25% less than the permissible span length for wind resistance. When the supports are placed throughout the station, a zigzag arrangement is carried out. The placement of zigzags on the air switches was done earlier when installing supports in the neck of the station. The placement of zigzags along each path begins with the zigzag indicated on the air arrow of this path in one of the station necks. In the middle part of the station, zigzags should be placed along each track, alternately directed under each rigid (flexible) cross member in one direction or the other from the track axis. If it turns out that in the opposite neck the zigzag on the air switch along the path in question does not correspond with the arranged zigzags, then the contact wires of this path on one of the rigid crossbars must be mounted without a zigzag (with a zero zigzag), where the length of the adjacent suspension spans is the smallest. Sectioning of the station contact network is carried out in accordance with the power supply and sectioning diagram. The station plan should show the installation locations of sectional insulators, sectional disconnectors and insulators included in the fixing cables of rigid or flexible crossbars, as well as in non-working branches of chain hangers for the electrical division of the station contact network into separate sections. Isolating connections between the station and adjacent sections are already shown on the plan. All supports shown on the station plan are numbered in the direction of kilometer counting, starting from the first isolation anchor support at one end of the station to the last interface anchor support at the other end of the station. The dimensions of the supports (the distance from the front edge of the supports to the axis of the track) are indicated before the type of supports (for example G3.3 CC136,6-3). The normal dimensions of intermediate and transition cantilever supports and reinforced concrete racks of rigid crossbars at stations should be: 3.1 m on straight sections of track; 3.3 m on anchor supports. Within passenger platforms, supports should be installed with increased dimensions so that they do not interfere with the boarding and disembarking of passengers. The supports installed in front of the signals are sized so that the visibility of the signals is not impaired. 5
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CHECKING THE CONDITION, ADJUSTING AND REPAIRING THE LIMITEROVERVOLTAGE From anchorages and other protected places, arresters and surge arresters are installed at a distance of no more than two spans and only if this is not possible, no further than four spans. Installation of arresters and surge arresters on anchor supports with guys is not allowed. Contact line horn arresters are installed at an angle of 45-90° to the track axis on brackets, placing the cables at the same angle. When installing a horn arrester and arrester on a bracket, the distance from the support to the arrester must be at least 0.8 m. The presence of any wires and insulators above the horn arrester and arrester at a distance of less than 2 m is not allowed. The surge arrester is connected to the contact network through a horn arrester with a single air gap of 10 +2 mm for direct current and 80 +5 mm for alternating current, shunted by a fuse insert made of one copper wire with a diameter of 1.4 mm or two copper wires with a diameter of each 0.68 mm. Surge arresters and surge arresters are connected to electrical transverse electrical connectors of the contact network with M-70 or PBSM-70 wires, and on supply lines and overhead lines with wires with a cross-sectional area of at least 25 mm 2 for copper. Checking the condition, adjusting and repairing the surge suppressor Cast: electrician or electrician 6th category - 1; electrician 5th category - 1; electrician 4 categories - 1; electrician 3 category 1 (when working from a removable tower). Performed by removing voltage from the contact network and surge suppressor (SPD); along with and notification of the energy dispatcher indicating the time, place and nature of the work. When working on station tracks - in agreement with the station duty officer. When checking the condition, adjusting and repairing a surge suppressor, the following machines, mechanisms, protective equipment, instruments, tools, devices and materials are used: Insulating removable tower or railcar, pcs.................................................... 1 Extension ladder 9m, pcs................................................... .....................................1 Hanging ladder Zm, pcs................................................... .........................................1 Mounting clamp, pcs.................................................... ........................................1 Grounding rod, pcs. (according to the number specified in the order)................................2 Portable shunt rod, pcs................................................... ....................1 Template, pcs......................................................... .......... ..................................... ............1 Dielectric gloves, steam.................................................... ...............................2 Safety belt, pcs.................................. (according to the number of performers) Protective helmet, pcs................................................... ..........(according to the number of performers) Signal vest, pcs.................................................... .....(by number of performers) Portable radio station, set.................................................... ............................1 Signal accessories, complete ...................................................... ......................1 Contact line electrician's tool kit, set...................................1 First aid kit, set................................................... ........................................................ .......1 Preparatory work and permission to work: on the eve of work, submit an application to the energy dispatcher to carry out work with voltage relief using an insulating removable tower or railcar and issue warnings to trains about the operation of the removable tower or railcar, indicating the time, place and nature of the work; receive a work order and instructions from the person who issued it; select materials and parts for the arrester in accordance with the documentation. Check by external inspection the completeness, the quality of the condition of all elements and parts, the integrity of the insulators, and the presence of anti-corrosion protection. If necessary, run the threads on all threaded connections and apply lubricant to them. Clean insulators from contamination; select installation devices, protective equipment, signal accessories and tools, check their serviceability and expiration dates: Load them, as well as selected materials, structures and parts onto the vehicle, organize delivery together with the team to the place of work; notify the energy dispatcher about the time, place and nature of the work. Ensure that warnings are issued to trains regarding the operation of the removable tower. When working on station tracks, coordinate its implementation with the station duty officer by making an entry in the “Log of Inspection of Tracks, Switches, Signaling Devices, Communications and Contact Network”; upon arrival at the place of work, provide instructions on labor protection to all members of the team with a signature for everyone in the outfit. Distribute responsibilities between performers; determine the order of fencing the removable tower and deploy signalmen. Check by external inspection the technical serviceability of the removable tower (carriage), if necessary, clean the insulating parts from dust and dirt; by order of the energy dispatcher, remove voltage from the contact network, incl. with surge arresters and ground disconnected contact network devices and equipment. Carry out organizational and technical measures provided for in the work order, and grant admission to the team to carry out work. The technology for performing the work is shown in Table 5.1. Table 5.1 Sequential process flow diagram Name of operations Checking the surge arrester (Figure 5.1.) Install an insulating removable tower on path (carriage) at the surge suppressor (SPD). Hang two portable grounding rods on the contact wire on both sides of the work site, having previously connected them to the traction rail. Climb to the surge arrester bracket directly along the support or along a 9 m extension ladder, installing and securing it on a reinforced concrete support Install a shunt with a copper cross-sectional area of at least 50 mm between the grounding outlet and the arrester cable. Check the fastening of the surge suppressor to the bracket and the bracket to the support. If necessary, tighten bolts and nuts. Check the condition of insulators and connection points. Operation of surge arresters with chips, cracks on the insulators, violation of the tightness of the surge arrester and other deviations is not allowed. Use a template to check the shape of the arc extinguishing horns and the dimensions of the air gap between the horns, as well as the reliability of fastening the horns to the insulators. The arcing horns must be located in a vertical plane. The size of the air gap between the horns is 10+2mm in DC sections, and -80+5mm in AC sections. The fuse link on the arc extinguishing horns should be copper wire with a diameter of 0.68 mm, 2 pcs. Check the connection of the grounding drain to the surge arrester and the double fastening of the cable from the contact network. Remove the shunt from the surge arrester. Checking the connection of the cable to the catenary and the grounding descent to the traction rail Check the fastening of the surge arrester cable at the suspension point on the supporting cable, and the connection of the surge arrester cable to the transverse electrical connector. Surge suppressor (OSL) loops must be connected on the contact network to transverse electrical connectors using M-70 or PBSM-70 wires (Fig. 5.2) Check the fastening of the grounding outlet from the arrester to the support. They must be isolated from the support and the ground and connected to the traction rail with bolted connections or to the midpoint of the track choke transformers. A red boom must be installed at the connection point to the rail. Figure 5.1 DC surge suppressor (a); AC surge arrester (b): bracket; 2 arrester beam; 3 support bar; 4.5 arc extinguishing horns; 6 surge arresters; 7 insulator; 8, 9, 10 connecting, string, grounding clamps; 11 - hook bolt; 12 wire 2 0.68 mm; 13 wire M-70 or PBSM-70 Figure 5.2 Installation of surge arresters on a support: a general view; b connecting the grounding descent to the traction rail; 1 surge arrester bracket; 2 overvoltage limiter (OSL); 3
plume; 4 insulator (suspension point of the loop); 5 transverse electrical connector; 6 traction rail; 7 hook bolt (or grounding attachment unit (UZK-1); 8 grounding descent (steel bar with a diameter of at least 12 mm for direct current and 10 mm for alternating current); 9 safety warning sign. Completion of work: collect materials, installation equipment, tools, protective equipment and load them onto the vehicle. Remove people from the work area; remove the removable tower from the path, install it on the field side of the support and lock it. Remove the signalmen fencing the work area. Disconnect the ladder from the support and lower it to the ground. Bring the railcar into transport position; give a notification to the energy dispatcher about the completion of the work, make an entry in the “Log of inspection of tracks, turnouts, signaling devices, communications and contact networks”; return to the ECHK production base. 6
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SAFETY WHEN PERFORMING WORKON THE CONTACT NETWORK With regard to safety measures, all work on the contact network is divided into the following main categories: with voltage relief and grounding; under voltage; near live parts; away from live parts. At working with voltage relief and grounding completely remove the voltage and ground the wires and equipment they operate on .
The work requires increased attention and highly qualified service personnel!; since wires and structures may remain energized in the work area. Approaching wires under operating or induced voltage, as well as neutral elements at a distance of less than 0.8 m, is prohibited. When working under voltage the employee is in direct contact with parts of the contact network that are under operating or induced voltage .
In this case, the safety of the worker is ensured by the use of basic protective equipment: insulating removable towers, insulating working platforms of railcars and railcars, insulating rods that isolate the worker from the ground. In order to increase the safety of performing work under voltage, the performer in all cases hangs up shunt rods, which are necessary to equalize the potential between the parts that he simultaneously touches, and in case of breakdown or overlap of the insulating element. When working under voltage, pay special attention attention to ensure that the worker does not simultaneously touch grounded structures and is at a distance of no closer than 0.8 m from them. Working near live parts are carried out on permanently grounded supporting and supporting structures, and between working and live parts there may be a distance of less than 2 m, but in all cases it should not be less than 0.8 m If the distance to live parts is more than 2 m, then this work is classified as performed away from live parts. At the same time, they are divided into work with lifting and without lifting to a height. Work at height is considered to be all work performed with a rise from ground level to the worker’s feet to a height of 1 m or more. During work with voltage relief and grounding and near live parts, it is prohibited: work in a bent position if the distance from the worker when straightening to dangerous elements is less than 0.8 m; work in the presence of electrically hazardous elements on both sides at a distance of less than 2 m from the worker; carry out work at a distance closer than 20 m along the track axis from the sectioning site (sectional insulators, insulating connections, etc.) and the disconnector loops that are used to disconnect when preparing the work site; use metal stairs. When working under voltage and near live parts, the team should have a grounding rod in case of urgent need to relieve the voltage. Organizational measures to ensure the safety of workers: issuing a work order; briefing to those issuing the outfit; issuance of permission to prepare a place of work; supervision during work; scheduling breaks. Technical measures to ensure the safety of workers: track closures; relieving operating stress and taking measures against its erroneous supply; checking for lack of voltage; applying grounding connections, shunt rods or jumpers, switching on disconnectors, switches of adjacent sections for the same type of current at docking stations; illumination of the work place at night. LITERATURE 1. Bondarev N.A., Chekulaev V.E. Contact network. M.; Route, 2006. 2. Doldin V.L. (edited) Reconstruction and modernization of contact networks and overhead lines. Part 1.2 M.: “Transport book” 2009. 3. Safety instructions for overhead line electricians. M.: Tekhinform, 2010. 4. Teaching and monitoring multimedia computer program “Supports of the contact network”. M.: UMK MPS Russia, 2001. 5. Training and control system for the safety of work on the contact network. M.: UMK MPS Russia, 2001. 6. Instructions for maintenance and repair of supporting structures of the contact network K-146-2002. M.: "Transizdat", 2010. 7. Reference manual for overhead line electricians - M.: “Transizdat”. 2007. INITIAL DATA 1. Suspension characteristics 2. Meteorological conditions 3. Path profile Embankment height Curve Radius Posted on Allbest.ru Determination of the maximum permissible span lengths of a contact network substation. Power supply and partitioning wiring diagram, station installation plan. Characteristics of sectional disconnectors and drives to them. Calculation of the load on catenary wires. course work, added 04/24/2014 Determination of contact network wires and selection of suspension type, design of overhead contact network routing. Selection of contact network supports, supporting and fixing devices. Mechanical calculation of the anchor section and construction of installation curves. thesis, added 06/23/2010 Calculation of span lengths on straight and curved sections in maximum wind conditions. Tension of overhead wires. Selection of supporting and supporting structures. Checking the possibility of placing supply wires and DPR wires on the contact network supports. thesis, added 07/10/2015 Drawing up installation plans for the contact network of the station and section, project for the electrification of the railway section. Calculation of span lengths and tension of wires, power supply of the contact network, routing of the contact network on the stretch and supporting devices. course work, added 06/23/2010 Determination of loads acting on overhead wires. Determination of maximum permissible span lengths. Tracing of the contact network of the station and section. Passage of catenary under a pedestrian bridge and on a metal bridge (with driving on the bottom). course work, added 03/13/2013 Determination of loads acting on the contact network wires for a station. Determination of maximum permissible span lengths. Calculation of the station anchor section of a semi-compensated spring suspension. The procedure for drawing up a station and stage plan. course work, added 05/18/2010 Design of the organization and production of construction and installation works for the construction of a contact network and installation of a traction substation. Determining the volume of construction and installation work, choosing and justifying the method of their production, calculating the necessary costs. course work, added 08/19/2009 Determination of the volume, labor intensity, time of construction and installation work on the construction of a section of the contact network. Calculation of the need for technological “windows” in the train schedule. Drawing up and calculating network work schedules. course work, added 03/18/2015 Determination of permissible span lengths on the main and secondary tracks of the station and on the direct section of the haul route. Plan of the station contact network. Calculation of the anchor section of the suspension on the main track. Selection of intermediate cantilever reinforced concrete support. course work, added 02/21/2013 Determination of loads acting on overhead wires on the main and side tracks of a station, on a stretch, and embankment. Calculation of span lengths and station anchor section of semi-compensated chain suspension. The procedure for drawing up a station and stage plan. Contact network is a set of devices for transmitting electricity from traction substations to EPS through current collectors. It is part of the traction network and for electrified rail 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. When designing a contact network (CN), 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 movement of the EPS and other current collection conditions; find the span lengths (mainly 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; place supports and draw up plans for the contact network at stations and stages with coordination of zigzags of wires and taking into account the implementation of overhead switches and sectioning elements of the contact network (insulating interfaces of anchor sections and neutral inserts, sectional insulators and disconnectors). 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 protected from the electrocorrosive effects of stray currents on their reinforcement. Increasing the service life of contact wires is achieved, as a rule, by using inserts on pantographs with high antifriction properties (carbon, including metal-containing, metal-ceramic, etc.), choosing a rational design of pantographs, as well as optimizing current collection modes. Anchoring of wires is the attachment of catenary wires 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 a given tension. In the middle of the catenary anchor section, a middle anchorage is performed (Fig. 8.17), which prevents unwanted longitudinal movements towards one of the anchors and allows you to limit the area of damage to the catenary when one of its wires breaks. The middle anchorage cable is attached to the contact wire and the supporting cable with appropriate fittings. Compensation of wire tension (automatic regulation) 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. in compensators with drums of different diameters (Fig. 8.19), cables connected to the anchored wires are wound on a small diameter drum, and a cable connected to a garland of weights is wound on a larger diameter drum. The braking device is used to prevent damage to the catenary when the wire breaks. Under special operating conditions, especially with limited dimensions in artificial structures, slight differences in heating temperature of wires, etc., other types of compensators are used for catenary wires, fixing cables and rigid crossbars. The articulated clamp consists of three elements: the main rod, the stand and an additional rod, at the end of which the contact wire fixing clamp is attached (Fig. 8.20). The weight of the main rod is not transferred to the contact wire, and it only takes part of the weight of the additional rod with a fixing clip. The rods are shaped to ensure reliable passage of the pantographs when they press 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 stand. On the outer side of curves of small radii, flexible clamps are mounted in the form of a conventional additional rod, which is attached to a bracket, rack or directly to a support through a cable and an insulator. On flexible and rigid crossbars with fixing cables, strip fasteners are usually used (similar to an additional rod), hingedly secured with clamps with an eye mounted on the fixing cable. On rigid crossbars, you can also attach clamps to special racks. Anchoring section is a section of a catenary suspension, the boundaries of which are anchor supports. Dividing 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 area in the event of a break in the catenary wires, facilitates installation, technical. contact network maintenance and repair. The length of the anchor section is limited by permissible deviations from the nominal tension value of the catenary wires set by the compensators. Conjugation of anchor sections is a functional combination of two adjacent anchor sections of a catenary system, ensuring a satisfactory transition of EPS pantographs from one of them to another without disturbing the current collection mode due to the appropriate placement in the same (transition) spans of the contact network of the end of one anchor section and the beginning of the other. A distinction is made between non-insulating (without electrical sectioning of the contact network) and insulating (with sectioning). Insulating interfaces are used when it is necessary to section the contact network, when, in addition to the mechanical one, it is necessary to ensure the electrical independence of the mating sections. Such connections are arranged with neutral inserts (sections of the catenary where there is normally no voltage) and without them. In the latter case, three or four span connections are usually used, placing the contact wires of the mating sections in the middle span(s) 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 transition 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 coupling. However, when the pantograph is in the middle span, the electrical independence of the anchor sections is compromised. If such a violation is unacceptable, neutral inserts of different lengths are used. It is chosen in such a way that when several pantographs of one train are raised, the simultaneous blocking of both air gaps is excluded, which would lead to the short circuit of wires powered from different phases and under different voltages. In order to avoid burning out the contact wire, the EPS is connected to the neutral insert on the run-down, for which purpose a signal sign “Turn off the current” is installed 50 m before the start of the insertion, and after the end of the insertion for electric locomotive traction after 50 m and for multiple unit traction after 200 m - the sign “ Turn on the current" (Fig. 8.21c). In areas with high-speed traffic, automatic means of switching off the current to the EPS are required. To make it possible to derail the train when it is forced to stop under the neutral insert, sectional disconnectors are provided to temporarily supply voltage to the neutral insert from the direction of train movement. In Fig. Figure 8.22 shows an example of a power supply and sectioning circuit for a station located on a double-track section of a line electrified with alternating current. The diagram shows seven sections - four on the hauls and three at the station (one of them with mandatory grounding when it is turned off). The contact network of the tracks of the left section and the station receives power from one phase of the power system, and the tracks of the right section - from the other. Accordingly, sectioning was carried out 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 manually operated sectional disconnector is sufficient. To section the contact network of the main and lateral networks at 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 not sufficient to accommodate insulating connections. Air switch - formed by the intersection of two overhead contacts above the switch; is designed to ensure 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 pantograph approaches the air needle, 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 intersection of contact wires above a single turnout is carried out with each wire shifted to the center from the track axes by 360-400 mm and located where the distance between the inner edges of the heads of the crosspiece connecting rails is 730-800 mm. At cross switches and at the so-called. At blind intersections, the wires cross over the center of the switch or intersection. Air gunners are usually fixed. To do this, clamps are installed on the supports to hold the contact wires in a given position. On station tracks (except for the main ones), switches can be made non-fixed if the wires above the switch are located in the position specified by adjusting the zigzags at the intermediate supports. The catenary strings located near the arrows must be double. Electrical contact between the catenary pendants forming the arrow is provided by an electrical connector installed at a distance of 2-2.5 m from the intersection on the arrow side. To increase reliability, switch designs with additional cross connections between the wires of both catenary pendants and sliding supporting double strings are used. Contact network supports are structures for fastening the supporting and fixing devices of the contact network, taking the load from its wires and other elements. Depending on the type of supporting device, supports are divided into cantilever (single-track and double-track); racks of rigid crossbars (single or paired); flexible crossbar supports; feeder (with brackets only for supply and suction wires). Supports that do not have supporting devices, but have fixing devices, are called fixing ones. Cantilever supports are divided into intermediate ones - for attaching one catenary suspension; transitional, installed at the junction of anchor sections, - for fastening two contact wires; anchor, absorbing the force from anchoring the wires. As a rule, supports perform several functions simultaneously. For example, the support of a flexible crossbar can be anchored, and consoles can be suspended from the racks of a rigid crossbar. Brackets for reinforcing and other wires can be attached to the support posts. For direct current sections, reinforced concrete supports are made with additional rod reinforcement located in the foundation part of the supports and designed to reduce damage to the support reinforcement by electrocorrosion caused by stray currents. Depending on the installation method, reinforced concrete supports and racks of rigid crossbars can be separated or non-separated, installed directly into the ground. The required stability of undivided supports in the ground is ensured by the upper beam or base plate. In most cases, undivided supports are used; separate ones are used when the stability of non-separated ones is insufficient, as well as in the presence of groundwater, which makes it difficult to install non-separated supports. In reinforced concrete anchor supports, guys are used, which are installed along the track at an angle of 45° and attached to the reinforced concrete anchors. Reinforced concrete foundations in the above-ground part have a glass 1.2 m deep, into which supports are installed and then the cavity of the glass is sealed with cement mortar. To deepen foundations and supports into the ground, the method of vibration immersion is mainly used. Console is a supporting device mounted on a support, consisting of a bracket and a rod. Depending on the number of overlapped paths, the console can be single-, double-, or less often multi-path. To eliminate the mechanical connection between catenaries of different tracks and increase reliability, single-track consoles are more often used. Non-insulated or grounded consoles are used, in which the insulators are located between the supporting cable and the bracket, as well as in the clamp rod, and insulated consoles with insulators located in the brackets and rods. Non-insulated consoles (Fig. 8.25) can be curved, inclined or horizontal in shape. For supports installed with increased dimensions, consoles with struts are used. At the junctions of anchor sections when installing 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 insulated consoles (Fig. 8.26), it is possible to carry out work on the supporting cable near them without disconnecting the voltage. The absence of insulators on non-insulated consoles ensures greater stability of the position of the supporting cable under various mechanical influences, which has a beneficial effect on the current collection process. The brackets and rods of the consoles are mounted on supports using heels that allow them to rotate along the track axis by 90° in both directions relative to the normal position. Flexible crossbar - a supporting device for hanging and fixing overhead wires located above several tracks. The flexible crossbar is a system of cables stretched between supports across electrified tracks (Fig. 8.27). Transverse load-bearing cables absorb all vertical loads from the chain suspension wires, the crossbar itself and other wires. The sag of these cables must be at least Vio the span length between the supports: this reduces the influence of temperature on the height of the catenary suspensions. To increase the reliability of the crossbars, at least two transverse load-bearing cables are used. The fixing cables take up horizontal loads (the upper one is from the supporting cables of the chain hangers and other wires, the lower one is from the contact wires). Electrical insulation of cables from supports allows servicing the contact network without disconnecting the voltage. To regulate their length, all cables are secured to supports using threaded steel rods; in some countries, special dampers are used for this purpose, mainly for fastening contact suspension at stations. Current collection is the process of transferring electrical energy from a contact wire or contact rail to the electrical equipment of a moving or stationary EPS through a current collector, providing sliding (on highway, industrial and most urban electric transport) or rolling (on some types of EPS of urban electric transport) electrical contact. Violation of contact during current collection leads to the occurrence of non-contact electric arc erosion, which results in intense wear of the contact wire and contact inserts of the current collector. When contact points are overloaded with current during movement, contact electrical explosion erosion (sparking) and increased wear of the contacting elements occur. Long-term overload of the contact with operating current or short-circuit current when the EPS is parked can lead to burnout of the contact wire. In all these cases, it is necessary to limit the lower limit of contact pressure for the given operating conditions. Excessive contact pressure, incl. as a result of the aerodynamic impact on the pantograph, an increase in the dynamic component and the resulting increase in the vertical deflection of the wire, especially at clamps, on air switches, 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 ensured by coordinated requirements for contact network devices and current collectors, which guarantees high reliability of their operation at minimal reduced costs. Rigid crossbar - used for hanging overhead wires located above several (2-8) tracks. The rigid crossbar 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 connected either hingedly or rigidly using struts, allowing it to be unloaded in the middle of the span and reducing steel consumption. When placing lighting fixtures on the crossbar, a flooring with railings is made on it; provide a ladder for climbing to the supports for service personnel. Install rigid crossbars ch. arr. at stations and separate points. Insulators are devices for insulating live contact wires. Insulators are distinguished according to the direction of application of loads and the installation location - suspended, tensioned, retaining and cantilever; by design - disc and rod; by material - glass, porcelain and polymer; insulators also include insulating elements The catenary is one of the main parts of the contact network; it is a system of wires, the relative arrangement of which, the method of mechanical connection, material and cross-section provide the necessary quality of current collection. The design of a catenary (CP) is determined by economic feasibility, operating conditions (maximum speed of movement of the EPS, maximum current drawn by pantographs), and climatic conditions. The need to ensure reliable current collection at increasing speeds and power of the EPS determined the trends in changes in suspension designs: first simple, then single with simple strings and more complex - spring single, double and special, in which, to ensure the required effect, Ch. arr. to level the vertical elasticity (or rigidity) of the suspension in the span, space-stayed systems with an additional cable or others are used. The quality of 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 wire’s own weight (in case of icy conditions along with ice) and wind load, as well as on the span length and tension of the wire. The quality of current collection is greatly influenced by the angle a (the smaller it is, the worse the quality of current collection), the contact pressure changes significantly, shock loads appear in the support zone, and increased wear of the contact wire and current-collecting inserts of the pantograph occurs. Current collection in the support zone can be somewhat improved by hanging the wire at two points (Fig. 8.10.6), which under certain conditions ensures reliable current collection at speeds of up to 80 km/h. It is possible to significantly improve 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 hangers are used (Fig. 8.11), in which the contact wire is suspended from the supporting cable using strings. A suspension consisting of a support cable and a contact wire is called single; if there is an auxiliary wire between the support cable and the contact wire - double. In a chain suspension, the supporting cable and the auxiliary wire are involved in the transmission of traction current, so they are connected to the contact wire by 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 upward. The quality of current collection depends on the nature of the change in elasticity over the span: the more stable it is, the better the current collection. In simple and conventional chain hangers, the elasticity at mid-span is higher than that of the supports. Equalization of elasticity 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 rational arrangement of ordinary strings in the middle part of the span. Double suspensions have more constant elasticity, but they are more expensive and more complex. To obtain a high index of uniform distribution of elasticity in the span, various methods are used to increase it in the area of the support unit (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 wire is the most critical element of the contact suspension, directly making contact with the EPS pantographs during the current collection process. Typically, one or two contact wires are used. Two wires are usually used when collecting currents of more than 1000 A. On domestic railways. d. 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 underwent some changes; in the beginning. 20th century the cross-section profile took the form with two longitudinal grooves in the upper part - the head, which serve to secure the contact network fittings to the wire. In domestic practice, the dimensions of the head (Fig. 8.12) are the same for different cross-sectional areas; in other countries, head sizes depend on 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 - shaped copper, cross-sectional area 150 mm2). In recent years, low-alloy copper wires with additives of silver and tin, which increase the wear and heat resistance of the wire, have become widespread. Bronze copper-cadmium wires have the best wear resistance (2-2.5 times higher than copper wire), but they are more expensive than copper wires, and their electrical resistance is higher. The feasibility of using a particular 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 highways. Of particular interest is the 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, contact wires wear out when collecting current. There are electrical and mechanical components of wear. To prevent wire breakage due to increased tensile stresses, the maximum wear value is normalized (for example, for a wire with a cross-sectional area of 100 mm, the permissible wear is 35 mm2); As wear on the wire increases, its tension is periodically reduced. Support cable - a chain suspension wire attached to the supporting devices of the contact network. A contact wire is suspended from the supporting cable using strings - directly or through an auxiliary cable. A string is an element of a catenary chain, with the help of which one of its wires (usually a contact wire) is suspended from another - the supporting cable. Reinforcing wire is a wire electrically connected to the contact suspension, serving 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 supporting cable. The reinforcing wire is used in areas of direct and alternating current. Reducing the inductive reactance of an AC contact network depends not only on the characteristics of the wire itself, but also on its placement relative to the overhead wires. An electrical connector is a piece of wire with conductive fittings intended for the electrical connection of overhead wires. There are transverse, longitudinal and bypass connectors. They are made from bare wires so that they do not interfere with the longitudinal movements of the catenary wires. Contact network fittings – clamps and parts for connecting overhead contact wires to each other, to supporting devices and supports. The fittings (Fig. 8.15) are divided into tension (butt clamps, end clamps, etc.), suspension (string clamps, saddles, etc.), fixing (fixing clamps, holders, ears, etc.), conductive, mechanically lightly loaded (clamps supply, connecting and transition - from copper to aluminum wires). The products included in the fittings, in accordance with their purpose and production technology (casting, cold and hot stamping, pressing, etc.), are made of malleable cast iron, steel, copper and aluminum alloys, and plastics. The technical parameters of the fittings are regulated by regulatory documents.
Similar documents
In a contact network with a catenary suspension, the main elements are the following: wires - contact wire, supporting cable, reinforcing wire, etc.; supports; supporting and fixing devices; flexible and rigid cross members (consoles, clamps); insulators and fittings for various purposes.
Contact networks with catenary suspensions are classified according to the type of electrified transport for which it is intended - railway. mainline, city (tram, trolleybus), quarry, mine underground rail transport, etc.; by the type of current and rated voltage of the EPS powered from the network; on the placement of the contact suspension relative to the axis of the rail track - for central current collection (on mainline railway transport) or lateral (on industrial transport tracks); by type of contact suspension - simple, chain or special; on the specifics of anchoring the contact wire and support cable, connecting anchor sections, etc.
The contact network is designed to operate outdoors and is therefore exposed to climatic factors, which include: ambient temperature, humidity and air pressure, wind, rain, frost and ice, solar radiation, and the content of various contaminants in the air. To this it is necessary to add thermal processes that occur when traction current flows through network elements, mechanical impact on them from pantographs, electrocorrosion processes, numerous cyclic mechanical loads, wear, etc. All contact network devices must be able to withstand the action of the listed factors and provide high quality of current collection in any operating conditions.
Unlike other power supply devices, the contact network does not have a reserve, so increased reliability requirements are placed on it, taking into account its design, construction and installation, maintenance and repair. Contact network design
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 Г from the axis of the outer track 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).
To increase the reliability of the contact network, ice is melted, incl. without interruption of train traffic; wind-resistant contact pendants are used, etc. The efficiency of work on the contact network is facilitated by the use of telecontrol for remote switching of sectional disconnectors. Wire anchoring
Wire Strain Compensation
The simplest is a block-load compensator, consisting of a load and several blocks (pulley hoist), through which the load is connected to the anchored wire. The most widely used is the three-block compensator (Fig. 8.18), in which a fixed block is fixed to a support, and two movable ones are inserted into loops formed by a cable carrying a load and fixed at the other end in the stream of a 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 rated tension (a 1:4 gear ratio is provided), but the movement of the load is twice as large as that of a two-6-lobe compensator (with one moving block). 
Contact wire clamp
Contact wire clamp – a device for fixing the position of the contact wire in a horizontal plane relative to the axis of the pantograph. 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.
A non-articulated clamp has one rod that pulls the contact wire from the axis of the pantograph to the support (extended clamp) or from the support (compressed clamp) by a zigzag size. On electrified railways non-articulated clamps are used very rarely (in anchored branches of a catenary suspension, on some air switches), since the “hard point” formed with these clamps on the contact wire impairs current collection. 
Anchor section
Deviations are caused by changes in the position of strings, clamps and consoles. For example, at speeds up to 160 km/h, the maximum length of the anchor section with bilateral 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 transition from one anchor section to the next, non-insulating and insulating connections are made. Pairing anchor sections
Non-insulating connections are made in all cases where it is necessary to include compensators in the catenary wires. In this case, mechanical independence of the anchor sections is achieved. Such connections are installed in three (Fig. 8.21, a) and less often in two spans. On high-speed highways, connections are sometimes carried out in 4-5 spans due to higher requirements for the quality of current collection. Non-insulating interfaces have longitudinal electrical connectors, the cross-sectional area of which must be equivalent to the cross-sectional area of the overhead wires. Catenary sectioning
Sectioning of a contact network is the division of a contact network into separate sections (sections), electrically separated by insulating connections of anchor sections or sectional insulators. The insulation may be broken during the passage of the EPS pantograph along the section interface; if such a short circuit is unacceptable (when adjacent sections are powered from different phases or 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 reliable operation of power supply devices in general, prompt maintenance and repair of the contact network with voltage cutoff. The sectioning scheme provides for such a mutual arrangement of sections in which the disconnection of one of them has the least impact on the organization of train traffic.
Sectioning of the contact network can be longitudinal or transverse. With longitudinal sectioning, the contact network of each main track is divided along the electrified line at all traction substations and sectioning posts. The contact network of stages, substations, sidings and passing points is divided into separate longitudinal sections. At large stations with several electrified parks or groups of tracks, the contact network of each park or groups of tracks forms independent longitudinal sections. At very large stations, the contact network of one or both necks is sometimes separated into separate sections. The contact network is also sectioned in long tunnels and on some bridges with traffic below. With transverse sectioning, the contact network of each of the main paths is divided 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 EPS, when it is necessary to use the cross-sectional area of the overhead catenaries of adjacent tracks.
Sectioning with mandatory grounding of the disconnected section of the contact network is provided for tracks on which there may be people on the roofs of cars or locomotives, or tracks near which lifting and transport mechanisms operate (loading and unloading, equipment tracks, etc.). To ensure greater safety for those working in these places, the corresponding sections of the contact network are connected to other sections by sectional disconnectors with grounding blades; these knives ground the disconnected sections when the disconnectors are turned off. 
The connection and disconnection of various sections of the contact network, as well as connection to the supply lines, is carried out using sectional disconnectors. On AC lines, as a rule, horizontal-rotating type disconnectors are used, on DC lines - vertical-cutting type. The disconnector is controlled remotely from consoles installed in the duty station of the contact network area, in the premises of station duty officers 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, V, D; 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 paths for equipping and inspecting the roofing equipment of EPS, on the paths for loading and unloading cars, etc.), disconnectors with one grounding blade are installed. Frog
Catenary supports
The supports are made of reinforced concrete, metal (steel) and wood. On domestic trains d. they mainly use 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, due to their load-bearing capacity or size, it is impossible to use reinforced concrete ones (for example, in flexible crossbars), as well as on lines with high-speed traffic, where increased requirements are placed on the reliability of supporting structures. Wooden supports are used only as temporary supports.
The metal supports of flexible crossbars are usually made of a tetrahedral pyramidal shape, their standard length is 15 and 20 m. Longitudinal vertical posts made of angle bars are connected by a triangular lattice, also made from angle iron. 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 cross beam 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 secure supports in rocky soils, heaving soils in areas of permafrost and deep seasonal freezing, in weak and swampy soils, etc., foundations of special structures are used. Console
Flexible crossbar
Current collection
The quality of current collection can be determined by various indicators (the number and duration of violations of mechanical contact on the calculated section of the track, the degree of stability of contact pressure close to the optimal value, the rate of wear of 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, research results and operating experience make it possible to identify the fundamental principles for creating current collection systems with the required properties. Rigid cross member
Insulators
Suspended insulators - porcelain and glass dish insulators - 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 supporting 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 securing the pipe. On AC lines, rod insulators are usually used, and on DC lines, disc insulators are also used. In the latter case, another disc-shaped insulator with an earring is included in the main rod of the articulated clamp. Cantilever porcelain rod insulators (Fig. 8.31) are installed in the 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 direct current lines, polymer insulating elements are used in the form of rectangular bars made of press material, and on alternating current lines - in the form of cylindrical fiberglass rods, on which electrical protective covers made of fluoroplastic pipes are put on. Polymer rod insulators with fiberglass cores and ribs made of organosilicon elastomer 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.Catenary
At speeds of up to 50 km/h, 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. 8.10a) or transverse cables. 
The catenary is an oscillating system, therefore, when interacting with pantographs, it can be in a state of resonance caused by the coincidence or multiple frequencies of its own oscillations and forced oscillations, determined by the speed of the pantograph along a span with a given length. If resonance phenomena occur, a noticeable deterioration in current collection may occur. The limit for current collection is the speed of propagation of mechanical waves along the suspension. If this speed is exceeded, the pantograph has to interact as if with a rigid, non-deformable system. Depending on the standardized specific tension of the suspension wires, this speed can be 320-340 km/h.
Simple and chain hangers consist of separate anchor sections. The suspension fastenings at the ends of the anchor sections can be rigid or compensated. On the main railways Mostly compensated and semi-compensated suspensions are used. In semi-compensated suspensions, compensators are present only in the contact wire, in compensated ones - also in the supporting cable. Moreover, 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 supporting cable, and therefore the vertical position of the contact wires, remains 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 supporting 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, insulating distances, especially in the area of artificial structures, etc.; in addition, a minimum inclination of the strings must be ensured at extreme values of ambient temperature, when noticeable longitudinal movements of the contact wire relative to the supporting cable may occur. For compensated suspensions, this is possible if the support cable and contact wire are made of different materials.
To increase the service life of the contact inserts of pantographs, the contact wire is placed in a zigzag plan. Various options for hanging the support cable are possible: in the same vertical planes as the contact wire (vertical suspension), along the axis of the track (semi-oblique suspension), with zigzags opposite to the zigzags of the contact wire (oblique suspension). The vertical suspension has less wind resistance, the oblique suspension has 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 supporting cable, are located at supports with opposite zigzags. In the middle parts of the spans, the wires are pulled together by rigid strips. In some suspensions, lateral stability is ensured by the use of two supporting cables, forming a kind of cable-stayed system in the horizontal plane.
Abroad, single chain suspensions are mainly used, including on high-speed sections - with spring wires, simple spaced support strings, as well as with supporting cables and contact wires with increased tension. Contact wire
During operation, rupture of the contact wire can occur as a result of the thermal effect of electric current (arc) in the area of interaction with another device, i.e., as a result of burnout of the wire. Most often, contact wire burnouts occur in the following cases: above the current collectors of a stationary 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 pantograph; presence of ice; closing the pantograph skid of the different-nopothecial 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, which prevents the pantograph from rising under load and forcibly turns it off when lowered; equipping the insulating interfaces of the anchor sections with protective devices that help extinguish the arc in the area of its possible occurrence; timely measures to prevent ice deposits on wires, etc. Support cable
On domestic trains On the main tracks of lines electrified with direct current, copper wire with a cross-sectional area of 120 mm2 is mainly used as a supporting cable, and on the side tracks of stations, steel-copper wire (70 and 95 mm2) is used. Abroad, bronze and steel cables with a cross-section from 50 to 210 mm2 are also used on AC lines. The cable tension in a semi-compensated catenary varies depending on the ambient temperature in the range from 9 to 20 kN, in a compensated suspension depending on the type of wire - in the range of 10-30 kN. String
By design, they are distinguished: link strings, composed of two or more hingedly connected links of rigid wire; flexible strings made of flexible wire or nylon rope; hard - in the form of spacers between the wires, used much less frequently; loop - made of wire or 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 trains The most widely used are 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 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 for link and other non-conducting strings. Sometimes non-conductive catenary strings made of nylon rope are used, the fastening of which requires transverse electrical connectors.
Sliding strings, capable of moving along one of the wires, are used in semi-compensated catenary pendants with a low structural height, when installing sectional insulators, in places where the supporting cable is anchored on artificial structures with limited vertical dimensions and in other special conditions.
Rigid strings are usually installed only on the overhead switches of the contact network, where they act as a limiter for the rise of the contact wire of one suspension relative to the wire of the other. Reinforcing wire
The use of reinforcing wire is provided for at the design stage; Typically, one or more A-185 type stranded wires are used. Electrical connector
Transverse connectors are installed for parallel connection of all overhead wires of the same track (including reinforcing ones) and at catenary stations for several parallel tracks included in one section. Transverse connectors are mounted along the track at distances depending on the type of current and the proportion of the cross-section of the contact wires in the general cross-section of the contact wires, as well as on the operating modes of the EPS on specific traction arms. In addition, at stations, connectors are placed in the places where the EPS starts and accelerates.
Longitudinal connectors are installed on the air switches between all the wires of the catenary pendants forming this switch, in the places where the anchor sections are coupled - on both sides for non-insulating joints and on one side for insulating joints and in other places.
Bypass connectors are used in cases where it is necessary to make up for the interrupted or reduced cross-section of the catenary suspension due to the presence of intermediate anchoring of reinforcing wires or when insulators are included in the supporting cable for passage through an artificial structure. Catenary fittings
