Details and dimensions of the contact network. Contact network design

Send your good work in the knowledge base is simple. Use the form below

Students, graduate students, young scientists who use the knowledge base in their studies and work will be very grateful to you.

Posted on http://www.allbest.ru

Posted on http://www.allbest.ru

Introduction

On electrified lines, electric rolling stock receives power through a contact network from traction substations located at such a distance between them that a stable rated voltage is ensured on the electric rolling stock and protection against short-circuit currents is provided.

The contact network is the most responsible integral part electrified railways. The contact network must ensure a reliable and uninterrupted supply of electricity to rolling stock in any climatic conditions. Devices contact network are designed in such a way that they do not limit the speed established by the train schedule and ensure uninterrupted current collection at extreme air temperatures, during the period of greatest ice formation on wires and during maximum speed winds in the area where the road is located. The contact network, unlike all other devices of the traction power supply system, does not have a reserve. Therefore, high demands are placed on the contact network, both in terms of improving designs, and in terms of the quality of installation work and careful maintenance under operating conditions.

The contact network is a contact suspension located in the correct position relative to the track axis with the help of supporting, fixing devices, which in turn are fixed to supporting structures.

The catenary, in turn, consists of a supporting cable and a contact wire (or two contact wires) connected to it by means of strings.

On the main tracks, depending on the category of the line, as well as on station tracks, where the speed of trains does not exceed 70 km/h, a semi-compensated chain suspension (KS-70) with vertical strings offset from the supports by 2-3 m and articulated clamps.

On the main and receiving and departure tracks, which provide for the non-stop passage of trains at speeds of up to 120 km/h, semi-compensated spring suspension KS-120 or compensated KS-140 is used.

On the main tracks of hauls and stations at train speeds of more than 120 (up to 160) km/h, as a rule, a compensated spring suspension with one or two contact wires KS-160 is used. On existing electrified lines, before renovation or reconstruction, the operation of semi-compensated spring suspensions KS-120 with articulated clamps and compensated spring suspensions KS-140 is allowed - 160 km/h.

On the railways of the Russian Federation there are several types of main contact suspensions; each suspension is selected for different operating conditions of transport (speed, current loads, climatic and other local conditions) based on a technical and economic comparison of options. This takes into account possible future increases in the speed and size of train traffic and the weight of freight trains.

Contact network supports, depending on the purpose and nature of the loads taken from the catenary wires, are divided into intermediate, transition, anchor and fixing.

Intermediate supports carry loads from the mass of catenary wires and additional loads on them (ice, frost) and horizontal loads from wind pressure on the wires and from changes in the direction of wires on curved sections of the track.

Transitional supports are installed in places where the anchor sections of catenary suspensions and air switches connect and take loads similar to intermediate supports, but from two catenary suspensions. The transition supports are also affected by forces from changing the direction of the wires when they are routed to the anchorage and on the arrow curve.

Anchor supports can only carry loads from the tension of the wires attached to them or, in addition, carry the same loads as intermediate, transition or fixing supports.

The fixing supports do not bear loads from the mass of the wires and perceive only horizontal loads from changes in the direction of the wires on curved sections of the track, on air switches, when retreating to anchorage and from wind pressure on the wires.

According to the type of contact network supporting devices mounted on supports, they are distinguished:

Cantilever supports with fastening on the catenary console of one, two or several tracks;

Supports with a rigid crossbar, or, as they are called, crossbars or portals, with fastening of contact suspensions of electrified tracks on a rigid crossbar (crossbar);

Supports with a flexible crossbar with fastening on it the contact suspensions of the electrified tracks covered by this crossbar.

To trace the contact network on single- and double-track sections (spans), reinforced concrete conical supports with a height of 13.6 m and a concrete wall thickness of 60 mm, type C, are used for sections alternating current and CO for sites direct current. Recently, CC and SSA supports have been introduced on direct and alternating current (Fig. 1).

The pillars of these supports are hollow conical jointless pipes made of prestressed reinforced concrete reinforced with high-strength wire. Transverse reinforcement is taken in the form of a spiral. To prevent tightening of the longitudinal reinforcement when winding the spiral along the length of the posts, installation of mounting rings is provided.

Mixed reinforcement is provided at the bottom of the supports - i.e. with the installation of additional non-prestressing reinforcement bars: for supports with a post height of 10.8 m by 2 meters from the bottom of the support, for supports with a height of 13.6 m - by 4 meters. Mixed reinforcement increases the crack resistance of supports.

The most important characteristic of supports is their load-bearing capacity - the permissible bending moment M0 at the level of the conventional edge - UOF, which is 500 mm below the level of the rail head (URR). Based on the load-bearing capacity, the types of supports are selected for use in specific installation conditions.

Picture 1

Reinforced concrete racks have holes: in the upper part - for embedded parts of supports, in the lower part - for ventilation (to reduce the influence of temperature differences between the outer and inner surfaces).

To install reinforced concrete supports, glass foundations of the DS-6 and DS-10 types are used. DS foundations consist of two main structural parts: the upper - the glass and the lower - the foundation part. Top part It is a reinforced concrete glass of rectangular cross-section. Bottom part The DS foundations have an I-section. The connection between the top of the foundation and the lower I-beam part is made in the form of a pyramidal cone.

To secure the tie rods of reinforced concrete anchor supports in the ground, I-beam anchors of the DA-4.5 type were used. The anchors are made of the same dimensions as the DS foundation, but without the glass part. To secure the guy ropes, strip steel eyes are installed in the upper part of the anchor.

The grounding of the contact network supports is carried out by individual grounding conductors connected to the traction rails using spark gaps, as well as by a group grounding cable for the supports located behind the platform.

The choice of supports begins, as a rule, with the calculation and selection of supports for curved sections of the track, because These conditions for installing supports are the most aggravated, especially in curves of small radii.

For the calculation, it is necessary to draw up a calculation diagram, showing on it all the forces acting on the support, and the shoulders of these forces relative to the point of intersection of the support axis with the UOF. The calculation of the total bending moments at the base of the supports is determined for three design modes according to standard loads: in the modes of ice with wind, maximum wind, minimum temperature. Based on the largest moment obtained, the support for installation is selected.

To maintain the wires at a given level from the rail head, supporting devices are used - brackets with rods, called consoles, which are classified:

According to the number of overlapped paths - single-track, in accordance with Figure 2 (a, b, c); double-track, in accordance with Figure 2 (d, e); in some cases three-track;

Shape - straight, curved, inclined;

According to the presence of insulation - non-insulated and insulated.

Figure 2 - Catenary consoles: a - curved inclined console; b - straight inclined console; c - straight horizontal; g - double-track horizontal with one locking post; d - double-track horizontal with two locking posts; 1 - bracket; 2 - traction; 3 - support; 4 - locking stand

The consoles used for fastening the wires of the catenary chain suspension are, as a rule, single-track - eliminating mechanical connection with other suspension brackets. According to the degree of insulation, they can be non-isolated from the contact network support, or isolated. Depending on the type of bracket location, there are inclined, curved and horizontal consoles. Inclined insulated consoles, regardless of the size of the support, are equipped with struts.

When routing a contact network, the type of consoles is selected depending on the type of support device (cantilever support, rigid cross member), size, installation location (straight section, internal or external side of a curve) and purpose of the support (intermediate, transitional), as well as the loads acting on the console . When selecting cantilever devices for a transition support, it is necessary to take into account the type of coupling of the anchor sections of catenary suspensions, the location of the working and anchored branches of the suspension relative to the support, and which of the branches is attached to this console.

The console consists of a bracket, a rod and a strut; it is hinged to the support using a heel and held on the support using a rod. The heels of the consoles and rods can be rotary or fixed; consoles that also have rotary units are called rotary. The cantilever rods, depending on the direction of application of loads, can be stretched or compressed.

Single-track consoles can be: non-insulated, when the insulators are located between the supporting cable and the bracket and in the clamp; insulated, in accordance with Figure 4, when the insulators are mounted in the bracket, rod and strut at the support; insulated with reinforced (double) insulation, in which there are insulators both in the bracket, rod and strut at the supports, and between the supporting cable and the bracket.

In recent years, insulated (Fig. 3) or non-insulated double straight inclined consoles (Fig. 4) have been installed with normal and increased dimensions, the bracket of which has a straight shape and consists of two channels with connecting strips or pipes.

Figure 3 - Insulated inclined single-track console: 1 - bracket; 2 - thrust (stretched); 3 - adjustment plate; 4 - lamellar yoke with earring; 5 - thrust (compressed); 6 - adjustment pipe; 7 - fixing bracket; 8 - strut

Figure 4 - Non-insulated straight inclined consoles: 1 - adjustable insert; 2 - console thrust; 3 - yoke; 4 - straight bracket; 5 - fixing brackets; 6 - clamps

Dynamic resistance to pressing of the pantograph is achieved by a more advanced design of the contact suspension. The verticality of the KS-200 suspension with a fixed position relative to the axis of the support cable path provides greater wind and dynamic stability than traditional suspensions for fastening the support cable of the main tracks with a zigzag corresponding to the zigzag of the contact wire; insulated horizontal consoles with a brace made of galvanized steel or aluminum pipes are used with the support cable secured in a rotating support saddle suspended on a horizontal rod of the console. The design of the consoles is designed for dimensions of 3.3--3.5 m; 4.9 m; 5.7 m and ensures convenience, speed and accuracy of their assembly. Additional clamps - made of aluminum profile, without wind strings; racks of articulated clamps - steel, galvanized. Single-track insulated consoles of the compensated catenary suspension of the main tracks on hauls and stations are installed on supports or on rigid crossbars on cantilever racks.

Figure 5 - Non-horizontal isolated console

For AC contact networks, insulated consoles are usually used, and for DC contact networks, non-insulated consoles are used.

Straight inclined non-insulated consoles made from two channels are designated by the letters NR (N - inclined, P - stretched rod) or NS (C - compressed rod), from a pipe - by the letters NTR (T - tubular) and NTS.

Insulated consoles made from pipes are designated ITR (I - insulated) or ITS, and those made from channels are designated IS or IR. The Roman numeral indicates the number of the console type along the length of the bracket, the Arabic numerals indicate the number of the channel from which the console bracket is made, the letter p indicates the presence of a strut, and the letter y indicates reinforced insulation. Inclined insulated consoles, regardless of the type and size of the support, must be equipped with struts.

On multi-track sections railway(stations), as well as in the case of installing supports with increased dimensions in the recesses behind the ditch, rigid crossbars are used. Rigid crossbars (crossbars) are metal trusses with parallel chords and a braced triangular lattice with spacers at each node. To strengthen the nodes, install another spacer diagonally. The individual truss blocks are joined together using angle steel plates (welded or bolted). Depending on the number of tracks covered by rigid crossbars, they can have a length from 16.1 to 44.2 m and are assembled from two, three and four blocks. Rigid crossbars with a design length of more than 29.1 m, on which floodlights are installed to illuminate station tracks, are equipped with decking and railings. The frame-type rigid crossbars are installed on reinforced concrete racks of type C and CA with a length of 13.6 m and 10.8 m.

Devices by which contact wires are held in a horizontal plane in the required position relative to the track axis (pantograph axis) are called clamps.

On the main tracks of stages and stations and receiving and departure tracks, where the speed exceeds 50 km/h, articulated clamps are installed, consisting of main and light additional rods connected directly to the contact wire.

The overturning of the high-speed catenary clamps (KS-200) is prevented by an unloaded wind string 600 mm long, connecting the additional clamp rod to the main rod (Fig. 7).

Direct clamps are used for negative (towards the support) zigzags of the contact wire or for horizontal force directed from the support in case of a change in the direction of the contact wire; reverse clamps - in case of positive (from the support) zigzags of the contact wire or horizontal force to the support (supporting device).

Figure 6 - Types of clamps: a - FP-3; b - UFP; c - FO-25; d - Ural Federal District; d - FR; 1, 8, 9 - insulators; 2 - articulation detail; 3 - main rod; 4 and 11 - racks of direct and reverse clamps; 5 - additional clamp; 6 - fixing clamp; 7 and 10 - inclined and safety strings; 12 - string and contact wire holders; 13 - steel thimble; 14 - UFO clamp stand

Figure 7 - Reverse latch with wind string: a - installation diagram of the wind string on the reverse latch; b -- installation diagram of the wind string on a direct clamp; c - general view of the wind string; 1 -- main reverse lock rod; 2 -- wind string; 3 -- fixing clamp; 4 -- additional clamp; 5 -- stand; 6 -- rod of the main direct lock

Figure 8 - Direct FP clamp with wind string

In case of large forces (more than 200N) from changing the direction of the contact wire, flexible clamps are mounted on the outside of the curve. The Rules for the Construction and Technical Operation of Contact Networks define the conditions for installing flexible clamps.

In the designations of clamps, letters and numbers indicate its design, the voltage in the contact network for which it is intended, and the geometric dimensions: F - clamp, P - direct, O - reverse, A - anchored branch, T - cable of anchored branch, G - flexible, C - air gun, R - diamond-shaped suspensions, I - insulated consoles, U - reinforced, number 3 - for voltage 3 kV (for DC lines), 25 - for voltage 25 kV (for AC lines); Roman numerals I, II, III, etc. - characterize the length of the main rod of the latch.

The lengths of the main rods of the clamps are selected depending on the installation dimensions of the supports, the direction of the zigzag of the contact wire, and the length of the additional rod. The length of the additional rod is assumed to be 1200 mm.

Clamps for insulated consoles differ from clamps for non-insulated consoles in that at the end of the main rod facing the console, instead of a rod with a thread for connection to the insulator, an eye is welded for connection to the console.

In those places where electrified railway tracks intersect, an intersection of corresponding contact pendants is formed in the contact network, which is called an air switch. Air switches must ensure a smooth, shock-free and spark-free transition of the pantograph skid from the contact wires of one track (exit) to the contact wires of another, free mutual movement of the pendants forming the air switch, and minimal mutual vertical movement of the contact wires in the area where the pantograph skid picks up the adjacent wire ways.

Figure 9 - Diagram of the overhead switch of the contact network: 1 - area of ​​passage of the non-working part of the pantograph skid under the non-working part of the contact wire; 2- main electrical connector; 3- non-working branch of the contact wire; 4 -- location area of ​​the fixing device; 5- zone for picking up contact wires by the pantograph skid; 6 -- direct path contact wire; 7 -- contact wire of the rejected path; 8 -- additional electrical connector; 9 -- place of intersection of contact wires

Air switches above ordinary and cross switches and above blind intersections of tracks must be fixed to ensure the possibility of mutual longitudinal movements of contact wires. On secondary routes it is allowed to use non-fixed air switches.

Strings are used to attach contact wires to the supporting cable in chain hangers. The strings must ensure elasticity of the suspension, and in a semi-compensated chain suspension, also the possibility of free longitudinal movements of the contact wire relative to the supporting cable when temperature changes. The string material must have the necessary mechanical strength, durability and resistance to atmospheric corrosion. The connection between the contact wire and the supporting cable should not be rigid, so the strings are made in separate links.

The link strings of chain pendants are made of steel-copper wire with a diameter of 4 mm (Fig. 10), the individual links are hingedly connected to each other. Depending on the length, the string can be made of two or more links, while the lower link connected to the contact wire must be no more than 300 mm long to avoid breaking. To reduce the wear of the strings, thimbles are installed at the junctions of the links. The link strings are attached to the contact wire and the supporting cable with string clamps, the double contact wires of the semi-compensated suspension are attached to common strings with separate lower links. When temperature changes, mutual movement of the contact wire and the supporting cable occurs (on both sides of the middle anchorage).

The mutual movement of the wires leads to skew of the strings. As a result, both the vertical position of the contact wire and the tension of the chain suspension wires change. To reduce this influence, the angle of inclination of the string should not exceed 30° to the vertical along the path axis (Fig. 10, c).

Figure 10 - Strings of chain contact pendants: a - link string; b and c - location of the string on a compensated and semi-compensated suspension; g - permissible inclination of the string to the vertical; 1 - load-bearing hummock; 2 - contact wire; 3 - pantograph skid; 4 - string clamp 046

For more uniform elasticity and to reduce the sag of the contact wire during temperature changes near the supporting structures, it is suspended on spring strings (cables) of the BM-6 brand. Spring strings are made of steel-copper wire with a diameter of 6 mm. Link strings are attached on one side to the spring string (cable) with string clamps or copper clamps, and on the other to the contact wire with the usual fastening of the strings with clamps.

To ensure the flow of current through all wires included in the catenary or through all wires included in one section, as well as in the case of unanchored wires on a support or bypassing an artificial structure, electrical connectors are used. Electrical connectors are installed at the junctions of anchor sections and individual sections at railway stations, at the junctions of reinforcing wires with contact suspension and supporting cables with contact wires. They must provide reliable electrical contact, elasticity of the contact suspension and the possibility of longitudinal temperature movements of the wires along the entire length.

Cross connectors (Fig. 11) are installed between all wires of the contact network belonging to one track or group of tracks (sections) at the station (contact, reinforcing wires and supporting cables). This connection ensures the flow of current through all parallel wires.

Longitudinal connectors (Fig. 12) are installed at the junction points of the anchor sections, at the points where the reinforcing and supply wires are connected to the catenary. The total cross-sectional area of ​​the longitudinal connectors must be equal to the cross-sectional area of ​​the suspensions they connect, and for reliable contact, longitudinal connectors on the main tracks and other critical places in the contact network are made of two or more parallel wires.

Figure 11 - Diagrams for installing transverse electrical connectors (a, b) and connecting reinforcing wires (c) and disconnector (arrester) cables to the contact suspension (d); 1 and 5 - connecting and supply terminals; 2- support cable; 3- electrical connector (MGG wire); 4 and 7-pin and reinforcing wires; 6- “C-shaped” electrical connector (wire M, A and AC); 8- loop from the disconnector (arrester, surge arrester); 9-clamp adapter

Figure 12 - Longitudinal electrical connector: 1 - electrical connector (MG wire); 2 - connecting clamp; 3 - support cable; 4 - contact wire; 5 - power clamp

Longitudinal electrical connectors must have a cross-sectional area corresponding to the cross-section of the pendants they connect. Longitudinal electrical connectors to the supply and reinforcing wires at anchors should be connected to the free ends emerging from the embedment, and at non-insulating connections and contours - to each supporting cable with two connecting clamps and to the contact wire with one supply clamp. With compensated suspension, the length of the electrical connector must be at least 2 m.

All types of electrical connectors and cables are made of M copper wires with a cross-section of 70-95 mm2 in alternating current sections; the use of MG copper wires of the same cross-section is allowed.

Transverse electrical connectors between the supporting cables and contact wires on the stages are installed outside the spring or first vertical strings at a distance of 0.2 - 0.5 m from their attachment points.

To power the contact network from traction substations, there are several traction power supply schemes. The most widely used are direct current systems with a voltage of 3.3 kV and alternating current systems with a voltage of 25 kV and 2x25 kV.

With a direct current power supply system, electrical energy enters the contact network from positive polarity buses with a voltage of 3.3 kV of traction substations and returns after passing through the traction motors of electric rolling stock along track circuits connected to the negative polarity buses. The distance between DC traction substations, depending on the load intensity, ranges from 7 km to 30 km.

In the AC power supply system, electricity is supplied to the contact network from two phases A and B with a voltage of 27.5 kV (on the busbars of traction substations) and returns along the track circuit to the third phase C. In this case, power is supplied in one phase counter to the feeder zone (parallel operation adjacent traction substations) with alternating power supply for subsequent feeder zones in order to equalize the loads of individual phases of the power supply system. With this power supply system, due to the high voltage, traction substations are located every 40-60 km.

In recent years, on the Russian railway network, along with the solution different problems and the assigned tasks, special attention is paid to the problem bandwidth stages and stations. This problem arises in conditions of fierce competition between railways and other sectors of the transport industry of the Russian Federation (maritime, automobile, etc.). Success in this largely depends on fast, high-quality and safe delivery cargo and passengers, which is greatly complicated by the constantly growing cargo turnover and passenger traffic. One of the most preferable solutions to this problem is to increase the weight of freight trains.

According to the instructions for organizing the movement of freight trains of increased length and weight, heavy trains are considered to be trains whose weight is more than 6000 tons or whose length is more than 350 axles.

The circulation of trains of increased weight and length is allowed on single- and double-track sections at any time of the day at a temperature not lower than -30 C, and for trains with empty cars - not lower than -40 C [L5].

Connected trains are organized at stations or stages from two, and in necessary cases from three trains, each of which must be formed according to the length of the receiving and departure tracks, but not more than 0.9 of their length, established by the schedule, as well as taking into account power restrictions traction and power of the locomotive and power supply devices.

Connecting and disconnecting trains of increased weight and length is permitted on descents and ascents up to 0.006, subject to traffic safety conditions stipulated by local instructions.

On electrified sections, the order of passage of connected freight trains is established according to the conditions of heating by the wire of the contact network of one track. The total current of all electric locomotives in trains of increased weight and length should not exceed the permissible current for heating the contact network specified in the Rules for the Construction and Technical Operation of the Contact Network of Electrified Railways. At sub-zero temperatures, the permissible currents of catenary wires can be increased by 1.25 times.

The number of trains of increased weight and length (for normal power supply) in the area between traction substations should be no more than that specified in the traffic schedule. At the same time, to calculate the load on power supply devices, a train of double unified weight and length is considered to be two trains, a triple train is considered to be three, etc.

Reducing the interval to a given value is possible by alternating the passage of heavy trains with lighter trains, introducing PS and PPS, or increasing the permissible current of the contact network.

The introduction of additional substations and substations on double-track sections with significant (at least twofold) different loads along the tracks makes it possible to reduce the calculated interval between trains by approximately 1.1 - 1.4 times due to a decrease in currents in the overhead wires.

The minimum inter-train interval is checked by the power of traction power supply devices, the voltage at the current collector of the electric locomotive, the current setpoint for the protection of supply lines (feeders) of traction substations, and the operation of elements of the traction rail circuit.

To organize the circulation of trains of increased weight and length on the roads, measures are being developed that include increasing the cross-sectional area of ​​the contact suspension, improving current distribution in wires, increasing the voltage level in the contact network and other measures.

One of the directions of transport policy is the further development of high-speed train traffic, which poses a number of new technical challenges for electrifiers. In international practice, the following classification has now been established: lines with a speed of 160-200 km/h are considered high-speed, and lines with a speed of over 200 km/h are considered high-speed.

It should be noted that changes in design solutions, in the choice of highly electrically conductive materials and corrosion-resistant coatings, in the use of new insulators, improved supporting and support structures, in the design of the contact suspension itself, etc., which appeared in connection with the introduction of the KS-200 suspension, show modern trends development of the contact network and are already widely used in the reconstruction carried out on a number of roads to increase traffic speeds to 160 km/h.

The labor and economic costs required for the operation and overhaul of the contact network on an extended range of electrified railways forces us to improve the design of the contact network, methods of their installation and maintenance.

The KS-200 contact network must provide reliable current collection with a number of pantograph passes of up to 1.5 million, high operational reliability, durability of at least 50 years, as well as a significant reduction in operating costs for its maintenance due to more advanced suspension characteristics: equalization of elasticity in spans; reducing the weight of clamps and fasteners, using compatible corrosion-resistant materials; anti-corrosion coatings; high thermal conductivity and low electrical resistance materials used.

There are several options for rebuilding the contact network. Modernization is carried out if the permanent elements of the contact network on the site have exhausted more than 75% of the standard service life (resource) and have reduced the bearing capacity or permissible loads by more than 25%. Depending on the volume of replacement of the main permanent elements, a complete or partial modernization of the contact network is carried out.

Complete modernization involves a complete update of all permanent elements of the contact network according to standard catenary designs. Contact wires are replaced depending on the degree of wear. The decision to preserve supports that were installed during a previous major overhaul and have not exhausted their service life is made during the design, depending on the possibility of using them in the suspension and the layout of the locations for installing the supports.

With partial modernization, a significant update of permanent elements is carried out and, if necessary, a complete update of individual elements - supporting structures, compensating devices, insulation, load-bearing cables, fittings.

1. Theoretical aspects of the designed site

Technical description of the designed site.

The technical description is a characteristic of the designed site, which should be presented in the following order:

Type of current and power supply system of the designed area;

Length of the station (distance between traffic lights), picketing of the axis of the passenger building;

The number of main and secondary tracks, the distance between tracks, the presence of dead ends and tracks that are not subject to electrification;

Availability of access roads to cargo yards and warehouses;

The length of the adjacent stretch and its characteristics (curves, embankments, excavations, artificial structures)

Development and description of the power supply and sectioning circuit for the contact network of the station and adjacent sections.

On electrified lines, the EPS receives electricity through the contact network from traction substations located at such a distance between them that a stable rated voltage on the EPS is ensured and protection against short-circuit currents works.

For each section of the electrified line, when designing it, a power supply and sectioning circuit for the contact network is developed. When developing power supply and sectioning circuits for the contact network of an electrified line, standard circuit diagrams sectioning, developed on the basis of operating experience, taking into account the costs of constructing a contact network.

The role of the “human factor” in ensuring train safety.

An analysis of literary sources shows that the activities of the world's railways have a lot in common, including problems. One of them is train safety.

Every human mistake is always the result of his action or inaction, i.e. manifestations of his psyche, determination of his aspect. The cause of an error is often not one, but a whole complex of negatively acting factors.

The operation of railway transport is inevitably associated with risk, which is defined as a measure of the probability of danger and the severity of damage (consequences) from a safety violation. Transport risk is the result of many factors, both subjective and objective. Therefore it will always exist. "The battle for security cannot be won once and for all."

An accident cannot be completely eliminated using technical or organizational measures. They only reduce the likelihood of its occurrence. The more effective the response to the risk of emergency situations, the higher the cost of effort and resources. Safety costs can sometimes even exceed losses from accidents, derailments and defects in train and shunting operations, which can lead to a temporary deterioration in the economic performance of the industry. And yet, such costs are socially justified and must be taken into account in economic calculations.

The safety of train traffic and the safety of the railway transport system is an integral concept that cannot be directly measured. Typically, safety means the absence (exclusion) of dangers. In this case, danger means any circumstance that can cause harm to human health and the environment, the functioning of the system, or cause material damage.

Train traffic safety is a central system-forming factor that unites the various components of railway transport into a single system.

Railway transport is the most important component of the economic activity of a modern state. Security breaches are associated with irrevocable economic, environmental and, above all, human losses.

Considering railway transport as a “man - technology - environment” system, we can distinguish four groups of factors influencing operational safety;

EQUIPMENT (failure of track and rolling stock, failure of signaling and communication equipment, safety devices, power supply, etc.);

TECHNOLOGY (violation and inconsistency of legislation, rules, regulations, orders, instructions, poor working conditions, contradictions between industry and external infrastructure, ergonomic deficiencies, developer errors technical means, incorrect control algorithms, etc.);

ENVIRONMENT (unfavorable objective conditions - terrain, meteorological conditions, natural disasters, increased radiation, electromagnetic interference, etc.).

A PERSON who directly manages technical equipment and performs supporting functions (incorrect performance of one’s production duties, intentionally or due to deteriorating health, insufficient preparedness, or inability to perform them at the required level).

Rail transport includes thousands of different technical means, which individually pose a danger to the environment and human life. In combination, human-machine systems pose a much greater danger, which must be taken into account during their development, implementation and operation. All this points to the need to create a safety theory - a methodological basis for measures to ensure safety on railways.

Any violation in equipment and technology is ultimately caused by a person, if not by the one who controls the technical means, then by the commander or maintenance personnel. Therefore, “... any violation of the correct functioning, firstly, secondly and thirdly, comes from a person.” On the railways Russian Federation Over the past five years, about 90% of all accidents and wrecks have been caused by human error.

People make mistakes, and this must be taken into account. A person has the right to make mistakes (of course, we are not talking about intentional violations). And the greater the deviation of a person’s state from his optimal state, the greater the likelihood of error. Therefore, it is necessary to build a security system in such a way as to minimize the consequences of these errors.

To effectively solve the problem of monitoring the human condition and building automatic devices, partially duplicating his actions, a modern approach is needed that considers a person in the relationship and interaction with his environment.

At the same time, the “human factor” is understood quite broadly. This:

Actions of managers, railway operators, workers not directly related to the movement of trains;

Various types of regulation, document flow, development and implementation of orders, instructions, regulations, rules, laws, etc.;

Selection, selection, placement and training of personnel in both managerial, engineering, technical, operator and blue-collar professions (personnel management);

Errors of developers of technical means and algorithms of technological processes;

Research and consideration of the influence of the specifics of the railway environment on the level of human health (working and rest conditions);

Control and evaluation current state workers (before the shift, during and after work).

Ensuring traffic safety is the most important task in railway transport and includes three relatively independent functions: structural and operational reliability; highly efficient management and reliability of the locomotive crew.

At the same time, if the percentage of occurrence of various technical and technological incidents plays a relatively small role, then the proportion of causes of marriage of “human” origin, united by the concept of “personal factor”, is very high.

A significant reserve here is the study of the causes of human-related incidents and, on this basis, the development of measures to eliminate them.

Occupational Safety and Health.

The workplace of electricians is an electrified area within the boundaries established for the contact network area.

Carrying out work on the contact network requires a solid knowledge of safety rules and their strict implementation.

These requirements are due to increased danger: work on the contact network is carried out in the presence of train traffic, with a rise to a height, in various meteorological conditions, sometimes in the dark, as well as close to wires and structures under high voltage, or directly on them without relieving tension, in compliance with organizational and technical measures to ensure the safety of workers.

Conditions for performing work.

When working with voltage relief and grounding, the wires and equipment that are being operated are completely removed and grounded. The work requires increased attention and highly qualified maintenance 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 comes into 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 elements. When working under voltage, pay special attention to this. so that the worker does not simultaneously touch grounded structures and is at a distance of no closer than 0.8 m from them.

Work near live parts is carried out on permanently grounded support and support structures, and there may be a distance of less than 2 m between workers and live parts, 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 being 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 interfaces, etc.) and the disconnector loops that are used to disconnect when preparing the work site;

Use metal ladders.

When working under voltage and near live parts, the team should have a grounding rod in case of urgent need to relieve the voltage.

At night, the work area must have lighting that ensures visibility of all insulators and wires at a distance of at least 50 m.

Dangerous places on the contact network include:

mortise and sectional insulators separating loading and unloading routes, inspection routes for roof equipment, etc.;

rotting contact suspension and cables of disconnectors and arresters or surge arresters of another section of the contact network with different potentials passing above it at a distance of less than 0.8 m;

supports where two or more disconnectors, arresters or anchorages of various sections are located;

places where consoles or clamps of different sections come together at a distance of less than 0.8 m;

places of passage of supply, suction and other wires along the cables of flexible crossbars;

common racks of clamps of various sections of the contact network with a distance between clamps of less than 0.8 m;

supports with anchor waste of catenary suspension of various sections and grounded anchor waste, the distance from the place of work on which to live parts is less than 0.8 m;

location of electrorepellent protection;

supports with a horn arrester or surge arrester, on which the suspension of one track is mounted, and the loop is connected to another track or feeder route.

Dangerous places on the contact network are indicated with special warning signs and indicators (red arrow or poster “Attention! Dangerous place”). Work to ensure safety in such places is carried out in accordance with the “Card of Work in a Dangerous Place of the Contact Network”.

Card of work in a dangerous place on the contact network.

Organizational measures to ensure the safety of workers are:

issuing a permit or order to the work contractor;

briefing of the person issuing the work order to the responsible manager, the work performer;

issuance by the energy dispatcher of permission (order, approval from the dispatcher) to prepare the work site;

Instruction by the work manager of the team and permission to work:

supervision during work;

registration of breaks in work, transitions to another workplace, extension of work order and completion of work.

Technical measures to ensure the safety of workers are:

closing tracks and stations for train traffic, issuing warnings for trains and fencing the work site;

relieving work stress and taking measures against erroneous application of it to the place of work;

*checking for lack of voltage;

*applying ground connections, shunt rods or jumpers, turning on disconnectors;

* illumination of the work place in the dark.

Monitoring compliance with safety rules is carried out primarily in the team directly at the work site. In addition, the organization of work in the area of ​​the contact network is periodically checked.

The work of the brigade on the line is regularly checked by the heads of the contact network area - a supervisor or an electrician. Periodic checks are carried out by managers and engineering staff of the power supply distance and electrification and power supply services. At the same time, the discipline of the team in ensuring labor safety and the competence in carrying out and organizing work are assessed.

The basis successful work without injuries and disruptions to normal operation - maintaining constantly stable production and technological discipline at all levels, preventing violations of current rules and instructions.

2. Calculation and technological part

Determination of loads acting on overhead wires.

For the contact network, the decisive factors are climatic loads: wind, ice and air temperature, acting in different combinations. These loads are random in nature: their calculated values ​​for any period of time can be determined by statistical processing of observation data in the area of ​​the electrified line.

To establish the estimated climatic conditions, they use zoning maps of the territory of Russia; for simplified calculations, data for assignments are provided by the teacher.

The load from the weight of the wires is a uniformly distributed vertical load, which can be determined using the literature.

Ice load is caused by ice, which is a layer of dense ice with a glassy structure with a density of 900 kg/m3. For calculations, we assume that the ice falls in a cylindrical shape with a uniform thickness of the ice wall; in terms of its impact, the load is vertical.

The intensity of ice formations is greatly influenced by the height of the wire above the ground. Therefore, when calculating the thickness of the ice wall on wires located on embankments, the value of the ice wall thickness should also be multiplied by the correction factor kb.

Wind loads on overhead wires depend both on the average wind speed and on the nature of the surface of the surrounding area and the height of the wires above the ground. In accordance with the building codes and regulations “Loads and impacts. Design standards "calculated wind speed for given conditions (the height of the wires above the surface and the surface roughness of the surrounding area) is determined by multiplying the standard wind speed by the kv coefficient, which depends on the height of the wires above the ground and its roughness, the standard value of wind pressure, Pa, q0, the coefficient of wind pressure unevenness along the span, in the mechanical calculation adopted.

The wind load on the catenary wires is a horizontal load.

From the different combinations of meteorological conditions acting on the wires of the contact network, three design modes can be distinguished, in which the force (tension) in the supporting cable can be the greatest, i.e. dangerous for the strength of the cable:

· minimum temperature mode - cable compression;

· maximum wind mode - cable stretching;

· ice conditions with wind - stretching of the cable.

For these design modes, the loads acting on the supporting cable are determined. In the minimum temperature mode, the supporting cable experiences only a vertical load - from its own weight; there is no wind and ice; in the maximum wind mode, the support cable is subject to a vertical load from the weight of the catenary wires and a horizontal load from the wind pressure on the support cable; there is no ice. In the mode of ice with wind, the support cable is subject to vertical loads from the dead weight of the catenary wires, from the weight of ice on the suspension wires, and the horizontal load from wind pressure on the support cable covered with ice at the corresponding wind speed.

So, we will calculate the loads for three design modes, the calculation procedure is given below.

Payment procedure.

In minimum temperature mode.

1. Selection of loads from the own weight of the supporting cable and contact wire.

Linear loads from the weight of the contact wire to (N/m) and the weight of the supporting cable (N/m) are determined depending on the type of wire according to the tables.

where, k - linear loads from the own weight (1 m) of the supporting cable and contact wire, N/m.

The load from the own weight of the strings and clamps, taken evenly distributed along the span; the value of this load can be taken equal to 1.0 N/m for each contact wire;

Number of contact wires.

where 0.009 N/mm3 is the density of ice;

d - diameter of the supporting cable;

Thickness of the ice wall on the supporting cable, mm

where kb is a correction factor that takes into account the influence of local conditions of the suspension location on ice deposition (Appendix 5, v. 5.7);

0.8 - correction factor to the weight of ice deposits on the support cable.

The standard thickness of the ice wall bн, mm, at a height of 10 meters with a repeatability of 1 time in 10 years, depending on the given icy area, is found according to Appendix 5 (t.5.6)

The calculated thickness of the ice wall, taking into account correction factors, may be rounded to the nearest whole number.

On contact wires, the calculated thickness of the ice wall is set equal to 50% of the wall thickness adopted for other wires of the contact network, since this takes into account the reduction of ice formation due to the movement of electric trains and melting of ice (if any).

where is the thickness of the ice wall on the contact wire, mm. On contact wires, the thickness of the ice wall is taken equal to 50% of the thickness of the ice wall on the supporting cable.

where is the thickness of the ice wall on the supporting cable, mm.

5. Full vertical load from the weight of ice on the catenary wires.

where is the number of contact wires;

The vertical load from the weight of the ice on the strings and clamps with one contact wire (N/m), uniformly distributed along the span length, which, depending on the thickness of the ice wall, can be approximately taken according to Appendix 5 (t.5.6).

6. The standard value of the horizontal wind load on the support cable in N/m is determined by the formula:

Similar documents

Determination of standard loads on overhead wires. Calculation of wire tension and permissible span lengths. Development of power supply and station partitioning circuits. Drawing up a contact network plan. Selecting a method for passing a catenary chain suspension.

course work, added 08/01/2012


Calculation of the main parameters of the AC contact network section, loads on the chain suspension wires. Determination of span lengths for all characteristic places by calculation method and using a computer, drawing up a power supply and partitioning diagram.

course work, added 04/09/2015


Mechanical calculation of a catenary chain suspension. Determination of span lengths on straight and curved sections of the track. Drawing up a power supply diagram and sectioning of the contact network. Passage of contact suspension in artificial structures. Calculation of equipment cost.

course work, added 02/21/2016


Tension of supporting cables of overhead catenary chains. Linear (distribution) loads on catenary wires for railway transport. Simple and chain air suspensions. Features of the rail network as a second traction wire.

course work, added 03/30/2012


Determination of the maximum permissible span length of a catenary chain on a straight section of track and in a curve. Bending moments acting on intermediate cantilever supports, selection of support types. Requirements for contact wires.

test, added 09/30/2013


Requirements for power supply and sectioning circuits of the contact network, graphical symbols of its devices. Schematic diagrams of power supply for a single-track and double-track section of a contact network and their economic efficiency. Sectioning devices.

test, added 10/09/2010


Calculation of traffic sizes, electricity consumption, power of traction substations. Type and number of traction units, cross-section of overhead wires and type of contact suspension. Checking the cross-section of the catenary by heating. Short circuit currents.

course work, added 05/22/2012


Construction of railway electrification, development of a contact network: climatic, engineering and geological conditions, type of contact suspension; calculations of loads on wires and structures, span lengths, selection of a rational technical solution.

course work, added 02/02/2011


Project of a section of a contact network. Calculation of loads on wires. Determination of permissible span lengths. Mechanical calculation of the anchor section of the station's semi-compensated catenary suspension. Selection of racks of contact network supports. Site failure risk assessment.

thesis, added 06/08/2017


Development and justification of the power supply and sectioning circuit for the contact network of the station and adjacent sections. Calculation of loads acting on the suspension. Determination of span lengths on straight and curved sections of the track. Current repair of consoles and their classification.

Contact network devices

CS is a complex system consisting of many devices. Each of them performs its own individual function. According to the functionality, the requirements for individual elements KS. General requirements relate to mandatory serviceability, compliance with quality standards, and safety.

CS devices usually include: all supporting and supporting structures that are designed to ensure a reliable and stable position of the leading current elements of the CS, organized by the suspension method; parts for fastening and fixing the CS along the supports of the CS or overhead lines on individual overhead line supports; supporting and auxiliary cables of different designs and different purposes depending on the design requirements of the compressor station; the KS wires themselves, which represent the main wire (it is called the contact wire), as well as wires for other purposes - reinforcing, suction, power supply, auto-blocking power supply. devices, power supply, etc.

In the process of work, almost all elements of the CS are influenced by various factors. The largest share of this influence comes from natural environmental factors. Throughout its entire working life, the CS is in the open air, therefore it is constantly exposed to the influence of precipitation, wind, sudden changes in temperature, ice conditions, etc. All these conditions negatively affect the state of the CS and its operation, causing a change in the lengths of the wires, the occurrence of sparking phenomena, and electric current. arcs, the phenomenon of corrosion for supports and other metal elements. It is not possible to completely get rid of these phenomena, however, it is possible to improve the network’s resistance to the external environment using various technical and technological methods, as well as the use of resistant and reliable materials in construction.

The compressor station must provide maximum resistance to external environmental factors, and, moreover, ensure uninterrupted movement of EPS along a line with established standards for weight, speed, schedule and interval between trains passing one after another.

Particular attention should be paid to the stability and reliability of the CS also because, unlike other power supply lines, it does not provide for a reserve. That is, this means that if any of the elements of the compressor system fails, this will lead to complete shutdown lines. It will be possible to resume the movement of rolling stock only after the necessary repair work has been carried out and supply has been restored.

2017 - 2018, . All rights reserved.

EXPLANATORY NOTE.

The guidelines are intended for full-time and part-time students of the Saratov Technical School of Railway Transport - a branch of SamGUPS in the specialty 02/13/07 Electrical supply (by industry) ( railway transport). Guidelines are drawn up in accordance with the work program professional module PM 01. Maintenance of equipment of electrical substations and networks.

As a result of execution practical work according to MDK 01.05 “Installation and maintenance of contact networks”, the teacher must:

master professional competencies:

PC 1.4. Equipment maintenance distribution devices electrical installations;

PC 1.5. Operation of overhead and cable power lines;

PC 1.6. Application of instructions and regulatory rules in the preparation of reports and development of technological documents;

have general competencies:

OK 1. Understand the essence and social significance of your future profession, show sustained interest in it;

OK 2. Organize your own activities, choose standard methods and methods of performing professional tasks, evaluate their effectiveness and quality;

OK 4. Search and use information necessary for the effective performance of professional tasks, professional and personal development;

OK 5. Use information and communication technologies in professional activities;

OK 9. To navigate the conditions of frequent changes in technology in professional activities;

have practical experience:

Software 1. compilation electrical diagrams devices of electrical substations and networks;

Software 4. maintenance of equipment of switchgears of electrical installations;

Software 5. operation of overhead and cable power lines;

be able to:

U 5 monitor the condition of overhead and cable lines, organize and carry out work on their maintenance;

9 use regulatory technical documentation and instructions;

know:

Conventional graphic symbols of electrical circuit elements;

The logic of constructing circuits, standard circuit designs, schematic diagrams of operating electrical installations.

Types and technologies of work on maintenance of switchgear equipment;

Designing a station contact network is a complex process and requires a systematic approach when implementing the project using advances modern technology and best practices, as well as the use of computer technology.

The guidelines address the issues of determining distributed loads on the supporting cable of an overhead catenary, determining the length of the equivalent and critical span, determining the tension values ​​of the supporting cable depending on temperature, and constructing installation curves.

According to the given station layout, the following is required:

1. Calculation of distributed loads on the overhead catenary cable for main and side tracks.

4. Determination of the sag value of the contact wire and support cable for the main track, with the construction of curves. Calculation of the average string length.

5. Organization of safe work.

Individual assignments for practical work are given immediately before completion, in class. The time to complete each practical work is 2 academic hours, the time to defend the work done is 15 minutes included in the total time.

General guidance and control over the progress of practical work is carried out by the teacher of the interdisciplinary course.

PRACTICAL LESSON No. 1

SELECTION OF PARTS AND MATERIALS FOR CONTACT NETWORK UNITS

Purpose of the lesson: learn how to practically select parts for a given chain suspension.

Initial data: type and assembly of the catenary chain (set by the teacher)

Table 1.1

Table 1.2

When choosing a support unit and determining the method of anchoring the wires of the catenary chain, it is necessary to take into account the speeds of trains along a given section and the fact that the higher the speed of trains, the greater the elasticity of the catenary chain.

Contact network fittings are a set of parts intended for fastening structures, fixing wires and cables, and assembling various components of a contact network. It must have sufficient mechanical strength, good compatibility, high reliability and the same corrosion resistance, and for high-speed current collection, it must also have minimal weight.

All parts of contact networks can be divided into two groups: mechanical and conductive.

The first group includes parts designed only for mechanical loads: wedge and collet clamps for the supporting cable, saddles, fork thimbles, split and continuous lugs, etc.

The second group includes parts designed for mechanical and electrical loads: collet clamps for joining the supporting cable, oval connectors, butt clamps for contact wire clamps, string, string and transition clamps. According to the material of manufacture, fittings are divided into: cast iron, steel, non-ferrous metals and their alloys (copper, bronze, aluminum).

Products made of cast iron have a protective anti-corrosion coating - hot-dip galvanizing, and products made of steel - electrolytic galvanizing followed by chrome plating.

Fig. 1.1 Anchoring of a compensated catenary suspension of alternating (a) and direct (b) current.

1- Anchor guy; 2- anchor bracket; 3,4,19 - steel compensator cable with a diameter of 11 mm, length 10,11, and 13 m, respectively; 5- compensator block; 6- rocker arm; 7- rod “eye-double eye” 150 mm long; 8- adjustment plate; 9- insulator with pestle; 10- insulator with earring; 11- electrical connector; 12- rocker arm with two rods; 13.22 - clamp, respectively, for 25-30 loads; 14- limiter for garlands of weights, single (a) and double (b); 15- reinforced concrete load; 16- load limiter cable; 17 load limiter bracket; 18- mounting holes; 20- pestle-eye rod, 1000 mm long; 21- rocker arm for attaching two contact wires; 23-bar for 15 loads; 24- limiter for a single garland of weights; H0 is the nominal height of the contact wire suspension above the level of the rail head; bM is the distance from the loads to the ground or foundation, m.

Rice. 1.2 Anchoring of a semi-compensated AC chain suspension with a two-block compensator (a) and DC with a three-block compensator (b).

1- anchor guy; 2- anchor bracket; 3- pestle-eye rod, 1000 mm long; 4- insulator with pestle; 5- insulator with earring; 6- steel compensator cable with a diameter of 11 mm; 7- compensator block; pestle-eye rod 1000 mm long; 9- bar for weights; 10- reinforced concrete load; 11- limiter for a single garland of weights; 12- load limiter cable; 13- load limiter bracket; 14- steel compensator cable with a diameter of 10 mm and a length of 10 m; 15- clamp for weights; 16- limiter for a double garland of weights; 17- rocker for anchoring two wires.

Fig. 1.3 Average anchorage of compensated (a-d) and semi-compensated (f) contact suspensions for a single contact wire (b), double contact wire (d), fastening the supporting cable and the average anchorage cable on an insulated console (c) and on a non-insulated console (d).

1- main support cable; 2- cable for the middle anchorage of the contact wire; 3- additional cable; 4-pin wire; 5- connecting clamp; 6- middle anchorage clamp; 7- isolated console; 8 - double saddle; 9- middle anchorage clamp for fastening to the supporting cable; 10- insulator.

Rice. 1.4 Fastening the support cable to a non-insulated console.

Rice. 1.5 Fastening the supporting cable to a rigid cross member: a - general view with a fixing cable; b- with a locking stand; and - triangular suspension with brackets.

1-support; 2- crossbar (crossbar); 3- triangular suspension; 4- fixing cable; 5- fixation stand; 6- latch; 7- rod with a diameter of 12 mm; 8- bracket; 9- earring with pestle; 10- hook bolt.

Execution order.

1. Select a support node for a given catenary and sketch it with all geometric parameters (Fig. 1.1, 1.2, 1.3,)

2. Select the material and cross-section of wires for simple and spring strings of the support unit.

3. Select using fig. 1.1, 1.2, 1.3, 1.4, 1.5, parts for a given unit, the name and characteristics of which must be entered in the table. 1.3.

Table 1.3

4. Apply a detail for joining the contact wire and connecting the support cable, which are also entered in the table. 1.3.

5. Describe the purpose and installation location of longitudinal and transverse connectors.

6. Describe the purpose of non-isolating interfaces. Draw a diagram of a non-insulating interface and indicate all the main dimensions.

7. Prepare a report. Draw conclusions.

Toolkit

To carry out practical exercises

In the discipline "Contact Network".

1. Selection of parts and materials for contact network nodes.

2. Determination of loads acting on the wires of the contact network.

3. Selection of standard consoles and clamps for a given support arrangement.

4. Calculation of the bending moment acting on the support and selection of a typical intermediate support.

5. Preparation of operational and technical documentation during work on the contact network.

6. Preparation of operational and technical documentation during the execution of work on the contact network.

7. Checking the technical condition, adjusting and repairing the air needle.

8. Checking the condition, adjusting and repairing the sectional insulator.

9. Checking the condition, adjusting and repairing the sectional disconnector.

10. Checking the condition, adjusting and repairing arresters of various types.

11. Checking the condition, adjusting and repairing the insulating interface.

12. Mechanical calculation of the anchor section of the catenary chain suspension.

13. Determination of the tension of a loaded support cable.

14. Calculation of sag arrows and construction of installation curves of the supporting cable and contact wire.

15. Making a list necessary materials, supporting and fixing devices for the overhead contact network.

Explanatory note.

The methodological manual contains options for practical classes in the discipline “Contact Network”. The purpose of the classes is to consolidate the knowledge acquired in the theoretical course of the discipline, acquire practical skills in checking the condition and adjusting individual nodes of the contact network, and skills in using technical literature. The topics of the proposed practical classes are chosen according to work program discipline and the current specialty standard 1004.01 “Power supply in railway transport”.

To carry out classes in the “Contact Network” classroom, you must have the basic elements of the contact network or their models, stands, the necessary posters, photographs, measuring and adjusting tools.

In a number of works, for better memorization and assimilation of the material, it is proposed to depict individual nodes of the contact network, describe their purpose and requirements for them.

When performing practical exercises, students must use reference, normative and technical literature.

You should pay attention to safety measures that ensure the safety of maintenance and repair work on overhead contact network devices.

Practical lesson No. 1

Selection of parts and materials for contact network nodes.

Purpose of the lesson: learn how to practically select parts for a given catenary system.

Initial data: type of catenary chain, catenary chain unit (set by the teacher according to tables 1.1, 1.2).

Table 1.1. Types of contact suspensions.

Table 1.2. Catenary chain assembly.

Brief theoretical information:

When choosing a support unit for a catenary chain and determining the method of anchoring the wires of a catenary chain, it is necessary to take into account the speeds of trains on a given section and the fact that the higher the speed of trains, the greater the elasticity of the catenary chain.

Contact network fittings are a set of parts intended for fastening structures, fixing leads and cables, and assembling various components of a contact network. The fittings must have sufficient mechanical strength, good compatibility, high reliability and the same corrosion resistance, and for high-speed current collection - also a minimum weight.

All parts of contact networks can be divided into two groups: mechanical and conductive.

The first group includes parts designed for purely mechanical loads. This includes: a wedge clamp, a collet clamp for a support cable, saddles, fork thimbles, split and continuous lugs, etc.

The second group includes parts designed for mechanical and electrical loads. This includes: collet butt clamps for joining the supporting cable, oval connectors, butt clamps for contact wire, string, connecting and transition clamps. According to the material of manufacture, fittings are divided into cast iron (malleable or gray cast iron), steel, non-ferrous metals and their alloys (copper, bronze, aluminum, brass).

Products made of cast iron have a protective anti-corrosion coating - hot-dip galvanizing, and products made of steel - electrolytic galvanizing followed by chrome plating.

Execution order practical lesson:

1. Select a support node for a given catenary and sketch it with all geometric parameters (L.1, p. 80).

2. Select the material and cross-section of wires for simple and spring strings of the support assembly.

3. Select parts for a given unit using L.9 or L10 or L11.

Enter the selected details into Table 1.3.

4. Select a part for joining the contact wire and connecting the support cable. Enter the selected details into Table 1.3.

Table 1.3. Parts for catenary units.

5. Describe the purpose and installation location of longitudinal and transverse electrical connectors.

6. Describe the purpose of non-isolating interfaces. Draw a diagram of a non-insulating interface and indicate all the main dimensions.

7. Prepare a report. Draw conclusions based on the completed lesson.

Control questions:

1. What loads do the contact network parts take?

2. What determines the choice of the type of support unit for a catenary chain?

3. In what ways can the elasticity of a catenary chain be made uniform?

4. Why can materials that are not highly conductive be used for load-bearing cables?

5. Formulate the purpose and types of middle anchors.

6. What determines the method of attaching the supporting cable to the supporting structure?

Fig.1.1. Anchoring of a compensated AC catenary suspension ( A) and permanent ( b) current:

1- anchor guy; 2- anchor bracket; 3, 4, 19 – steel compensator cable with a diameter of 11 mm, length, respectively, 10, 11, 13 m; 5- compensator block; 6- rocker arm; 7- rod “eye-double eye” 150 mm long; 8- adjustment plate; 9- insulator with pestle; 10- insulator with earrings; 11- electrical connector; 12- rocker arm with two rods; 13, 22 - clamp, respectively, for 25-30 loads; 15- reinforced concrete load; 16- load limiter cable; 17- load limiter bracket; 18- mounting holes; 20- pestle-eye rod, 1000 mm long; 21- rocker arm for attaching two contact wires; 23-bar for 15 loads; 24- limiter for a single garland of weights.

Fig. 1.2.Anchoring of a semi-compensated AC chain suspension with a two-block compensator ( A) and direct current with a three-block compensator ( b):

1- anchor guy; 2- anchor bracket; 3- rod “pestle-double eye” 1000 mm long; 4- insulator with pestle; 5- insulator with earring; 6- steel compensator cable with a diameter of 11 mm; 7- compensator block; 8- pestle-eye rod, 1000 mm long; 9- bar for weights; 10- reinforced concrete load; 11- limiter for a single garland of weights; 12- load limiter cable; 13- load limiter bracket; 14- steel compensator cable with a diameter of 10 mm and a length of 10 m; 15- clamp for weights; 16- limiter for a double garland of weights; 17- rocker for anchoring two wires.

Fig.1.3. Average anchorage compensated ( hell) and semi-compensated ( e) catenary chains; for a single contact wire ( b), double contact wire ( G); on an isolated console ( V) and on a non-isolated console ( d).

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 network theory, an 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, they strive to have the least possible impact on the transportation process while unconditionally ensuring high quality of work.
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 other permanent devices of the main railways: Pcs - contact network 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 form 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 parallel connection contact suspensions of various paths; 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 inter-substation 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 is a diagram that differs from the previous one in the presence of an electrical connection 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 contact networks of tracks for transmitting electrical energy to electric rolling stock, which provides significant energy savings in case of 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.
A parallel circuit is a circuit that differs from a nodal circuit in a large number of electrical nodes between the overhead contacts of the tracks. It is used when there is even greater unevenness in electricity consumption along the tracks. This scheme is especially effective when driving heavy trains.