Contact Rail Network Distance. Contact network device. Main elements. Terms and Definitions
Contact Network It is a complex of devices for transmitting electricity from traction substations to EPS through current collectors. It is part of the traction network and for rail electrified transport usually serves its phase (with alternating current) or pole (with constant toke); Another phase (or pole) is a rail network. The contact network can be performed with a contact rail or with a contact suspension.
In the contact network with contact suspension, the mains are next elements: Wires - contact wire carrying a cable, enhancing the wire, etc.; supports; support and fixing devices; flexible and rigid crossbars (consoles, locksters); Insulators and fittings for various purposes.
The contact network with contact suspension is classified by types of electrified transport for which it is intended, - J.-D. main, urban (tram, trolleybus), career, mining underground rail transport, etc.; by the nature of the current and the nominal voltage of the ePP feed from the network; on the placement of the contact suspension relative to the axis of the railway - for the central current collector (on the main railway transport) or lateral (on the ways of industrial transport); by contact suspension types - with simple, chain or special; According to the peculiarities of the configuration of the contact wire and the carrier cable, the interconnection of the anchor sites, etc.
The contact network is designed to work outdoors and is therefore exposed to climate factors to which include: ambient temperature, humidity and air pressure, wind, rain, frost and ice, solar radiation, content in the air of various contaminants. To this, it is necessary to add thermal processes arising from the flow of tract current on network elements, mechanical effects on them from current collectors, electrocorrosive processes, numerous cyclic mechanical loads, wear, etc. All contact network devices must be able to withstand the action of listed factors and provide high The quality of the current conversation in any operating conditions.
Unlike other power supply devices, the contact network does not have a reserve, therefore increased requirements for reliability, according to which its design, construction and installation, maintenance and repair are carried out.
Designing a contact network
When designing a contact network (COP), the number and brand of wires are chosen, based on the results of the calculation of the traction power supply system, as well as traction calculations; Determine the type of contact suspension in accordance with the maximum speeds of the EPS movement and other conditions of the current conversation; Find the length of the span (ch. arr. under the conditions of ensuring its wind resistance, and at high speeds of movement - and a given level of non-equilibrium elasticity); Select the length of the anchor sites, types of supports and supporting devices for distillers and stations; develop the designs of the CS in artificial structures; Place the supports and make up the plans of the contact network at stations and distillations with the coordination of zigzags of wires and taking into account the performing air arrows and elements of the partitioning of the contact network (insulating interference of the anchor sections and neutral inserts, sectional insulators and disconnectors).
The main dimensions (geometrical indicators), characterizing the placement of the contact network relative to other devices, is the height of hanging the contact wire above the top of the rail head; distance A from parts under stress to grounded parts of structures and rolling stock; The distance from the axis of the extreme way to the inner edge of the supports at the level of the rail heads is regulated and significantly determine the structural execution of the contact network elements (Fig. 8.9).
Improving the design of the contact network is aimed at improving its reliability while reducing the cost of construction and operation. Reinforced concrete supports and foundations of metal supports are performed with protection against the electrocorrosion impact on their immature of wandering currents. Increasing the service life of contact wires is achieved, as a rule, using inserts with high antifriction properties (coal, including metal-containing; metal-ceramic, etc.), the choice of rational constructs of current collectors, as well as the optimization of the current conversation modes.
To increase the reliability of the contact network, ice is smelted, incl. without interruption of trains; Apply wind-resistant contact suspensions, etc. The operational performance of work on the contact network contributes to the use of television management for remote switching section disconnectors.
Anchoring wires
Wiring Anchors - Attaching the wires of the contact suspension through the insulators and reinforcement included in them with the transmission of their tension on it. The wire anchoring is noncompensated (rigid) or compensated (Fig. 8.16) via a compensator, changing the length of the wire in the event of a change in its temperature while maintaining a given tension.
In the middle of the anchoring section of the contact suspension, the average anchoring is performed (Fig. 8.17), which prevents unwanted longitudinal movements towards one of the anchors and allows you to limit the damage zone of the contact suspension when one of its wires is broken. The medium anchoring cable is attached to the contact wire and the carrying cable of the corresponding reinforcement.
Wiring tension compensation
Compensation of wire tension (automatic adjustment) of the contact network with a change in their length as a result of temperature effects is carried out by compensators of various structures - driving-cargo, with drums of various diameters, hydraulic, gas-flow, springs, etc.
The most simple is a block and cargo compensator, consisting of cargo and several blocks (polyspaster), through which the cargo is attached to the enclosable wire. The highest distribution was obtained by a three-block compensator (Fig. 8.18), in which the stationary block is fixed on the support, and the two movable are nested in the loop formed by the cargo carrying and fixed by the other end in the strength of the fixed block. Ancker conductive wire through insulators is attached to the movable block. In this case, the weight of the cargo is 1/4 of the nominal tension (1: 4 gear ratio is provided), but the movement of cargo is twice as much as a two-6-tier compensator (with one moving block).
the compensators with the beams of different diameters (Fig. 8.19) on the small diameter drum, the cables associated with the ankurias were wedged, and the larger diameter drum is a cable associated with the cargo garland. The brake device is used to prevent damage to the contact suspension when the wire breaks.
Under specific operating conditions, especially with limited dimensions in artificial structures, minor seats of heat heating temperature, etc., apply compensators and other types for the wires of contact suspension, fixing cables and rigid crossbars.
Contact wire retainer
Contact Wire Lock - Device for fixing the position of the contact wire in the horizontal plane relative to the axis of current collectors. In curvilinear sites, where the levels of rail heads are different and the axis of the current collector does not coincide with the axis of the path, the absent and articulated clamps are used. The abnormal retainer has one rod, pulling the contact wire from the axis of the current collector to the support (stretched lock) or from the support (compressed fixator) on the size of the zigzag. On electrified w. D. Invented clamps are used very rarely (in the ankurped branches of the contact suspension, on some air arrows), since the "rigid point" in the contact wire impacts the current consumption.
The articulated fixer consists of three elements: the main rod, racks and an additional rod, at the end of which the locking clip of the contact wire is attached (Fig. 8.20). The weight of the main rod is not transmitted to the contact wire, and it only perceives part of the weight of the additional rod with a locking clip. Rods have a form that provides a reliable passage of current collectors when pressed by contact wire. For high-speed and high-speed lines, lightweight additional rods are used, for example, made of aluminum alloys. With double contact wire, two additional rods are installed on the rack. On the outside of the curves of small radii, flexible locks are mounted in the form of an ordinary additional rod, which is fixed to the bracket, rack or directly to the support through the cable and insulator. On flexible and rigid crossbars with fixing cables, strip locks are usually used (by analogy with an additional rod), fixed by hinged clamps with an eye installed on the fixing cable. On tough cross, you can also mount the locks on special racks.
Anchor plot
Anchor plot - a plot of contact suspension, the boundaries of which are anchor supports. The division of the contact network on the anchor sections is necessary to include in the wires of devices that support the tension of the wires when they change their temperature and implement the longitudinal partitioning of the contact network. This division reduces the damage zone in the event of a cliff of the contact suspension wires, facilitates installation, tehn. Maintenance and repair of the contact network. The length of the anchor section is limited by acceptable deviations from the compensators specified nominal value Tension wires of contact suspension.
Deviations are caused by changes in the position of strings, retainers and consoles. For example, at speeds of up to 160 km / h, the maximum length of the anchor area during bilateral compensation on direct sections does not exceed 1600 m, and at no more than 1,400 m km / h at speeds. In the curves, the length of the anchor sections is reduced. The greater the longer curve and less than its radius. To transition from one anchor area to the next, inconsistent and insulating pairs are performed.
Conjugation of anchor sites
Interconnecting of anchor sections is a functional integration of two adjacent anchor sections of the contact suspension, providing a satisfactory transition of EPS current applicants from one of them to another without disrupting the current collector, thanks to the corresponding placement in the same (transitional) spans of the contact network of the end of one anchor site and the beginning of the other. There are insistent interfacing (without electrical partitioning of the contact network) and insulating (with partitioning).
Inconsistent patterns are performed in all cases when compensators are required in the contact suspension wires. At the same time, the mechanical independence of the anchor sites is achieved. Such conjugations are mounted in three (Fig. 8.21, a) and less often in two spans. On high-speed conjugation highways, they are sometimes performed in 4-5 spans due to higher quality requirements. There are longitudinal electrical connectors on the uninsulant pairing, the cross-sectional area of \u200b\u200bwhich should be equivalent to the area of \u200b\u200bcross section of the contact network wires.
Insulating conjugations are used if necessary to partitioning a contact network when, in addition to mechanical, it is necessary to ensure the electrical independence of the conjugated sections. Such conjugations are arranged with neutral inserts (areas of contact suspension, on which normal voltage is missing) and without them. In the latter case, three-or-half-splash interfaces are usually used, having contact wires of conjugated sections on average flight (spans) at a distance of 550 mm one from the other (Fig. 8.21.6). At the same time, the air interval is formed, which, together with the insulators, included in the raised contact suspensions in transition supports, provides electrical independence of the anchor sections. The transition of a current receiver from the contact wire of one anchor area to another occurs in the same way as with a non-insistent interface. However, when the current receiver is on average, the electrical independence of the anchor sites is broken. If such a violation is unacceptable, neutral inserts of different lengths are used. It is chosen so that with several raised current collectors of one train, the simultaneous overlap of both air gaps was excluded, which would lead to a closure of wires feeding from different phases and under different stresses. Matching with a neutral insert To avoid the contact of the contact wire of the EPS runs on the election, for which 50 m before the insertion starts the signal sign "Turn off the current", and after the end of the insertion during the electric craft after 50 m and with a motor-speaking traction after 200 m - the sign " Turn on the current "(Fig. 8.21, B). On areas with high-speed motion requires automatic means of turning off the current on EPS. In order to derive the train during its forced stop below the neutral insert, section disconnectors are provided for a temporary supply of a neutral insertion from the direction of the train movement.
Partitioning of the contact network
Partitioning of the contact network - separation of the contact network into separate areas (sections) electrically disconnected by insulating pairing of anchor sections or sectional insulators. Insulation can be broken during the passage of the EPS current collector along the interface of the sections section; If such a closure is unacceptable (when feeding adjacent sections from various phases or accessories to them various systems traction power supply), between sections are neutral inserts. Under operating conditions, the electrical connection of individual sections is carried out, including sectional disconnectors installed in the appropriate places. Partitioning is also necessary for the reliable operation of power supply devices in general, operational maintenance and repair of the contact network with a voltage shutdown. The partitioning scheme provides such a mutual arrangement of sections, in which the shutdown of one of them in the smallest degree affects the organization of the train movement. The partitioning of the contact network is longitudinal and transverse. With longitudinal partitioning, the contact network is separated by each main path along the electrified line in all traction substations and partitioning posts. Separate longitudinal sections allocate a contact network of distillations, substations, travelings and overtaking items. At large stations with several electrified parks or paths of paths, the contact network of each fleet or paths of paths forms independent longitudinal sections. At very large stations, the contact network of one or both Gorlovin is sometimes distinguished into separate sections. The contact network is also partitioning in extended tunnels and on some bridges with a downgrade. With transverse partitioning, the contact network is separated by each of the main paths throughout the electrified line. At stations with significant ways to develop, additional transverse partitioning is used. The number of transverse sections is determined by the number and purpose of individual paths, and in some cases and the modes of touching the EPS, when it is necessary to use the cross-sectional area of \u200b\u200bthe contact suspension of adjacent paths.
Partitioning with the mandatory grounding of the disabled section of the contact network is provided for the paths on which people can be on the roofs of wagons or locomotives, or paths near which lifting and transport mechanisms (loading and unloading, equipment and other) are operating. To ensure greater security in these places, the corresponding contact network sections are connected to other sections sectional disconnectors with grounding knives; These knives ground the disconnected sections when disconnectors are turned off.
In fig. 8.22 A sample of the power scheme and partitioning of the station located on a two-way line of a line electrified on alternating current is given. The diagram shows seven sections - four on the distillations and three at the station (one of them with mandatory ground when it is turned off). The contact network of the lift paths and the station is powered by a single phase of the power system, and the paths of the right-time is different. Accordingly, partitioning is performed using insulating pairs and neutral inserts. In the areas where ice melting is required, two section disconnector with motor drives are installed on a neutral inset. If the ice is not provided, one sectional disconnector with a manual drive is enough.
Sectional insulators are used to partitioning the contact network of the main and side networks at stations. In some cases, sectional insulators are used to form an AC contact network of neutral inserts, which EPS passes without consuming current, as well as on paths, where the length of the congresses is insufficient to accommodate insulating pairs.
The connection and disconnection of various sections of the contact network, as well as the connection with the feeding lines is carried out using section disconnectors. On the AC lines, the horizontal-rotary-type disconnectors are used on the DC lines - vertically-chopping. Manage the disconnector remotely from the consoles installed in the duty station of the contact network area, in the premises of the duty officers at stations and in other places. The most responsible and often switchable disconnectors are installed in the network of dispatching television management.
The disconnectors are distinguished (for connecting and disconnecting the longitudinal sections of the contact network), transverse (for connecting and disconnecting its transverse sections), feeder and others. They are denoted by the letters of the Russian alphabet (for example, longitudinal-and b, b, g; transverse - ; feeder - f) and numbers corresponding to the paths of paths and sections of the contact network (for example, P23).
To ensure the safety of the work on the disconnected section of the contact network or near it (in the depot, on the EPS equipment and inspection paths, the EPS, on the ways of loading and unloading wagons, etc.) are installed disconnectors with one grounding knife.
Frog
The air arrow is formed by the intersection of two contact suspension over the arrow transmission; It is intended to ensure a smooth and reliable passage of the current collector from the contact wire of one path to the contact wire of the other. The crossing of the wires is carried out by overlaying one wire (as a rule, the adjoining path) to another (Fig. 8.23). To lift both wires when the current collector approachs the air arrow on the lower wire, a limiting metal pipe is strengthened with a length of 1-1.5 m. The top wire is located between the tube and the bottom wire. The intersection of contact wires over a single arrow transmission is carried out with the displacement of each wire to the center from the paths of the paths by 360-400 mm and are placed where the distance between the internal edges of the creston connecting heads is 730-800 mm. On cross-time translations and at t. The deaf intersections of the wire will be crossed over the center of the arrow translating or intersection. Aerial shooters are usually fixed. To do this, on the supports install the locks that hold the contact wires in the specified position. At the station paths (apart from the main), the arrows can be performed non-fixed if the wires above the arrow translation are located in a position specified by the adjustment of zigzags at the intermediate supports. The strings of the contact suspension, located near the arrows, must be double. The electrical contact between the contact suspensions forming the air arrow provides an electrical connector installed at a distance of 2-2.5 m from the place of intersection from the side of the point. To enhance reliability, the designs of the arrows with additional cross-links between the wires of both contact suspension and the sliding supporting double strings are used.
Support contact network
Contact Network Supports - Designs for fixing supporting and fixing devices of the contact network that perceive the load from its wires and other elements. Depending on the type of supporting device, the supports are divided into console (single and two-step execution); Stands of hard crossing (single or paired); Flexible supports; Feeder (with brackets only for feeding and suction wires). Supports on which there are no supporting, but there are fixing devices, are called fixing. Console supports are divided into intermediate - for mounting one contact suspension; transitional, installed on the pairing of anchor sections - to attach two contact wires; Anchor, perceiving effort from wire anchoring. As a rule, the supports simultaneously perform several functions. For example, the flexibility support can be anchor, the console can be suspended on the racks of rigid crossbars. We can fix brackets for reinforcing and other wires to the supports of the supports.
Supports are made by reinforced concrete, metal (steel) and wooden. On domestic w. d. Used mainly support from pre-stressed reinforced concrete (Fig. 8.24), conical centrifuges, standard length 10.8; 13.6; 16.6 m. Metal supports are installed in cases where it is impossible to use reinforced concrete (for example, in flexible cross) on the bearing capacity or size, as well as on high-speed lines, where elevated requirements for the reliability of support structures are presented. Wooden supports apply only as temporary.
For DC sections, reinforced concrete supports are made with an additional rod reinforcement located in the foundation part of the supports and is intended to reduce the damage to the plotting of the electrocorrosion, caused by the wandering currents. Depending on the installation method, reinforced concrete supports and racks of rigid crossbar are separate and inseparable, installed directly into the ground. The required stability of inseparable supports in the ground is provided by the upper bed or support plate. In most cases, inseparable supports are used; Separates are used in case of insufficient stability of inseparable, as well as in the presence of groundwater, which impede the installation of inseparable supports. In anchor reinforced concrete supports, exhaust are used, which are installed along the path at an angle of 45 ° and are attached to reinforced concrete anchors. Reinforced concrete foundations in the aboveground part have a glass of 1.2 m deep, into which supports are installed and then close the sinuses of the glass with cement mortar. For the showering of the foundations and supports in the ground, use predominantly method of vibrating driving.
Metal supports of flexible crossing are usually made by a four-step pyramidal shape, their standard length 15 and 20 m. Longitudinal vertical racks made of angular rolled products are connected by a triangular grid, made also from the corner. In areas that are characterized by increased atmospheric corrosion, metallic cantilever supports with a length of 9.6 and 11 m are fixed in the ground on reinforced concrete foundations. Console supports are installed on prismatic three-fluorescent foundations, supports of flexible crossbreaks - either on separate reinforced concrete blocks, or on pile foundations with woodworks. The base of metal supports is connected to the foundations of anchor bolts. To secure the supports in rock soils, bunched soils of the everlasting and deep seasonal freezing, in weak and wetlands, etc. Apply the foundations of special designs.
Console
The console is a supporting device fixed on a support consisting of a bracket and thrust. Depending on the number of overlapping paths, the console may be single, two- and less often multiple. To eliminate the mechanical connection between contact suspensions of various ways and increasing reliability, one-page consoles are more often used. Apply uninsulated, or grounded consoles, in which the insulators are located between the carrier cable and the bracket, as well as in the clamp terminal, and the insulated consoles with insulators placed in the brackets and traction. Uninsulated consoles (Fig. 8.25) in shape can be curved, inclined and horizontal. For supports installed with increased dimensions, apply consoles with pins. On the interfacing of the anchor sections when installing on one support, two consoles use a special traverse. The horizontal consoles are used in cases where the height of the supports is sufficient to fix the inclined thrust.
With isolated consoles (Fig. 8.26) it is possible to carry out work on the carrying cable near them without disconnecting the voltage. The absence of insulators on uninsulated consoles ensures greater stability of the position of the carrier cable at various mechanical stress, which favorably affects the process of the current conversation. Brackets and tights of consoles are attached to the supports with the help of spots allowing them to turn along the axis of the path 90 ° in both directions relative to the normal position.
Flexible crossing
Flexible crossing is a supporting device for hanging and fixing the wires of the contact network located above several paths. Flexible crossing is a system of cables stretched between supports across electrified paths (Fig. 8.27). Transverse bearing cables perceive all vertical loads from chain suspension wires, the coordinates itself and other wires. The arrow of the provision of these cables should be at least VIO the length of the span between the supports: it reduces the effect of temperature to the height of the attachment of contact suspensions. To increase reliability, no less than two transverse bearing cables are used.
Fixing cables perceive horizontal loads (the upper - from the carrier cables of chain suspension and other wires, the lower - from the contact wires). Electrical insulation of cables from support allows you to maintain a contact network without disconnecting the voltage. All cables for regulating their length are fixed on supports using steel carving rods; In some countries, special dampers are used for this purpose, mainly for mounting the contact suspension at stations.
Current
The current consumption is the process of transmitting electrical energy from the contact wire or contact rail to the electrical equipment of a moving or stationary EPS through a current collector providing a sliding (on the main, industrial and most of the city electric transport) or rolling (on some types of urban electric transport) electrical contact. The contact impairment at the current conversation leads to the occurrence of non-contact electric arc erosion, the consequence of which is the intensive wear of the contact wire and contact inserts of the current receiver. When overloading contact points current in motion mode, contact electronvary erosion (sparking) and increased wear of contacting elements occur. Long-term contact overload by the operating current or current of the KZ when the EPS parking can lead to the contact wire facing. In all these cases, it is necessary to limit the lower limit of the contact press for the specified operating conditions. Excessive contact press, incl. As a result of aerodynamic impact on a current receiver, an increase in the dynamic component and caused by the increase in vertical exhaustion of the wire, especially at the fixators, on the air arrows, in the places of interference of the anchor sections and in the area of \u200b\u200bartificial structures, can reduce the reliability of the contact network and current collectors, as well as increase the intensity of wear Wires and contact inserts. Consequently, the upper limit of contact pressing is also necessary to normalize. The optimization of the current conversation modes provide coordinated requirements for contact network devices and current collectors, which guarantees high reliability of their operation with minimal spending.
The quality of the current conversation can be determined by different indicators (the number and duration of the disorders of the mechanical contact in the calculated section of the path, the degree of stability of the contact press, close to the optimal value, the intensity of the wear of the contact elements, etc.), which largely depend on the constructive implementation of interactive systems - the contact network Both current collectors, their static, dynamic, aerodynamic, damping and other characteristics. Despite the fact that the process of the current conversation depends on a large number of random factors, the results of research and operating experience make it possible to identify the fundamental principles of creating a current collecting system with the required properties.
Stiff cross
Rigid cross - serves to suspend the wires of the contact network located above several (2-8) paths. The rigid cross is performed in the form of a block metal structure (riglel) installed on two supports (Fig. 8.28). Such crossbars are also used for the exempted span. Rigel with racks is connected hinged or rigidly using a pod, allowing you to unload it in the middle of the span and reduce steel consumption. When placing on the riglel, the lighting devices are performed on it with railing; Provide a staircase for lifting on supporting personnel supports. Install tough crossbars ch. arr. at stations and separate items.
Insulators
Insulators - devices for insulation of the wires of the contact network under voltage. Distinguish insulators in the direction of the application loads and the installation site - suspended, stretch, fixative and console; According to the design - plate and rod; By material - glass, porcelain and polymer; Insulators also include insulating elements
Suspended insulators - porcelain and glass plate - are typically connected in the garlands of 2 on the DC lines and 3-5 (depending on air pollution) on the AC lines. Stretch insulators are installed in the anchors of the wires, in the carrier cables above sectional insulators, in fixing cables of flexible and rigid crossbars. Fixatory insulators (Fig. 8.29 and 8.30) differ from all other presence of inner threads in the hole of the metal caps for fixing the pipe. On the AC lines usually use rod insulators, and permanent - and disc. In the latter case, another plate insulator with an earring is included in the main stem of the articulated retainer. Console porcelain stem insulators (Fig. 8.31) are installed in the pan and traction of isolated consoles. These insulators must have an increased mechanical strength, since work on bending. In section disconnectors and horny arresters, usually apply porcelain rods, less often discoed insulators. In section insulators, polymer insulating elements are used in the form of rectangular bars from the press material, and on the alternating current lines-in the form of cylindrical fiberglass rods to which electrobatic covers from fluoroplastic pipes are attached. Polymer rod insulators with fiberglass cores and silicone elastomer are developed. They are used as suspended, partitioning and fixative; They are promising for installation in sinks and isolated consoles, in flexible cables, etc. In the areas of industrial air pollution and in some artificial structures, periodic cleaning (knee) of porcelain insulators is carried out using special mobile means.
Contact suspension
The contact suspension is one of the main parts of the contact network, is a wire system whose mutual location, a method of mechanical connection, material and section provide the necessary quality of the current conversation. The design of the contact suspension (KP) is determined by the economic feasibility, the operational conditions (the maximum speed of the EPS movement, the highest power of the current removable), and climatic conditions. The need to ensure a reliable current conversation with increasing speeds of movement and power EPS determined the trends in the constructions of the suspensions: first simple, then single with simple strings and more complex - sampling, double and special, in which to ensure the desired effect, ch. arr. Alignment of vertical elasticity (or rigidity) suspension in the span, space-guided systems with an additional cable or others are used.
At speeds of up to 50 km / h, satisfactory quality of the current conversation provides a simple contact suspension consisting only from a contact wire suspended to supports A and in the contact network (Fig. 8.10, a) or transverse cables.
The quality of the current conversation is largely determined by the wire of the wire, depending on the resulting load on the wire, which consists of the own weight of the wire (with ice together with ice) and wind load, as well as from the length of the span and tension of the wire. On the quality of the current conclusion, the angle A (than it is less, the worse the quality of the current-capacity), the contact pressing is significantly changed, shock loads appear in the support zone, the contact wire and the current collector inserts are reinforced. You can slightly improve the current consumption in the support zone by applying the wire hanging at two points (Fig. 8.10,6) that under certain conditions provides a reliable current consumption at speeds of up to 80 km / h. It is possible to significantly improve the current consumer with a simple suspension, only substantially reducing the length of the spans in order to reduce the arrow of the provision, which is in most cases uneconomically, or applying special wires with a significant tension. In this connection, chain suspensions are used (Fig. 8.11), in which the pin wire is suspended with the carrying cable using strings. The suspension consisting of a carrier cable and contact wire is called single; In the presence of auxiliary wire between the carrier cable and the contact wire - double. In the chain suspension, the carrying cable and auxiliary wire are involved in the transfer of traction current, so they are connected to the contact wire with electrical connectors or conductive strings.
The main mechanical characteristic of the contact suspension is considered elasticity - the ratio of the height of the contact wire to the applied to it and directed vertically upwards. The quality of the current conversation depends on the nature of the change of elasticity in the span: the more stable, the better the current consumption. In simple and ordinary chain suspensions, elasticity in the middle of the span is higher than that of the supports. Alignment of elasticity in a single suspension span is achieved by installing spring cuts with a length of 12-20 m, on which vertical strings are fixed, as well as the rational arrangement of ordinary strings in the middle of the span. Double suspensions are more constant elasticity, but they are more expensive. To obtain a high uniformity of the elasticity distribution in the span, various ways of increasing it in the zone of the support node (installation of spring shock absorbers and elastic rods, torsional effect from twisting cable, etc.) is used. In any case, when developing suspensions, it is necessary to take into account their dissipative characteristics, i.e. resistance to external mechanical loads.
The contact suspension is an oscillatory system, so when interacting with current collectors may be in a state of resonance caused by the coincidence or frequency of the frequencies of its own oscillations and forced oscillations determined by the speed of the current receiver in the span with a given length. In the event of resonant phenomena, there is a significant deterioration of the current conversation. The limiting for the current conversation is the speed of propagation of mechanical waves along the suspension. In case of exceeding this speed, the current receiver has to interact as it were with a tough, non-deformable system. Depending on the normalized specific tensions of the suspension wires, this speed may be 320-340 km / h.
Simple and chain suspensions consist of separate anchor sites. Fixing the suspension "At the ends of the anchor sites can be rigid or compensated. On trunk D. Apply mainly compensated and semi-perched suspensions. In semi-permanent suspensions, compensators are available only in the contact wire, in compensated - also in the bearer cable. At the same time, in the event of a change in the temperature of the wires (due to the passage of currents, changes in the ambient temperature) of the carrier cable arrow, and therefore the vertical position of the contact wires remain unchanged. Depending on the nature of the change in the elasticity of the suspension in the span, the contact wire is tested in the range from 0 to 70 mm. The vertical adjustment of semi-permanent suspensions is carried out so that the optimal arrow of the contact wire is matched the average annual (for a given area) ambient temperature.
The constructive height of the suspension is the distance between the carrier cable and the contact wire at the suspension points - are chosen on the basis of technical and economic considerations, namely, taking into account the height of the supports, the observance of the current vertical dimensions of the approximation of buildings, insulating distances, especially in the area of \u200b\u200bartificial structures, etc.; In addition, the minimum string is provided with extreme ambient temperature values \u200b\u200bwhen noticeable longitudinal movements of the contact wire relative to the carrier cable may occur. For compensated suspensions, this is possible if the carrying cable and contact wire are made of various materials.
To increase the service life of the contact inserts of current collectors, the contact wire is placed in terms of zigzag. Various versions of the suspension of the carrier cable are possible: in the same vertical planes as the contact wire (vertical suspension), along the axis of the path (semi-axis suspension), with zigzags opposite to the contact wire zigzags (oblique suspension). The vertical suspension has less wind resistance, oblique - the greatest, but it is most complex when installing and maintaining. In direct portions of the path, a semi-axis suspension is used, on curvilinear - vertical. In areas with particularly strong wind loads, a diamond-shaped suspension is widely used, in which two contact wires suspended with the total carrier cable are located at the supports with opposite zigzags. In the middle parts of the spans, the wires are attracted by one to other rigid straps. In some suspensions, transverse stability is provided by using two bearing cables forming in the horizontal plane of a kind of guy system.
Abroad mainly use chain single suspensions, including at high-speed areas - with spring wires, simple spaced strings, as well as with carrier cables and contact wires having increased tension.
Contact wire
The contact wire is the most responsible element of the contact suspension directly by contacting the EPS current collectors during the current conversation. As a rule, one or two contact wires are used. Two wires are usually used when removing currents of more than 1000 A. on domestic w. d. Apply contact wires with a cross-section area 75, 100, 120, less often 150 mm2; Abroad - from 65 to 194 mm2. The shape of the cross section of the wire underwent some changes; in the beginning. 20 V. The section profile has acquired a form with two longitudinal grooves at the top of the head, which is serving to secure on the fixture of the contact network. In domestic practice, the sizes of the head (Fig. 8.12) are the same for various areas of section; In other countries, the sizes of the head depend on the cross-section area. In Russia, the contact wire is marked with letters and numbers indicating material, profile and cross-sectional area in mm2 (for example, MF-150 is a copper shaped area of \u200b\u200b150 mm2).
In recent years, low-alloyed copper wires with silver additives, tin, which increase the wear and heat resistance of the wire are widespread. The best values \u200b\u200bfor wear resistance (2-2.5 times higher than the copper wire) have bronze copper-cadmium wires, but they are more expensive than copper, and their electrical resistance is higher. The feasibility of applying a wire is determined by a technical and economic calculation, taking into account specific operating conditions, in particular, in solving issues of ensuring a current conversation on high-speed highways. A certain interest is a bimetallic wire (Fig. 8.13), suspended mainly at the receiving and sending pathways of stations, as well as a combined steel aluminum wire (the pin part is steel, Fig. 8.14).
During operation, the wear of contact wires at a tok conversation occurs. There are electrical and mechanical components of wear. To prevent the wiring break due to the increase in tensile stress, the maximum wear value is normalized (for example, for wires with a cross-sectional area of \u200b\u200b100 mM, allowable wear is 35 mm2); As the wear wear increases, its tension periodically reduces its tension.
When operating, the termination of the contact wire may occur as a result of the thermal effects of electric current (arc) in the interaction area with another device, i.e. as a result of the wire facing. Most often, the adjoins of the contact wire occur in the following cases: above the current collectors of the stationary EPS due to the KZ in its high-voltage circuits; When climbing or lowering the current receiver due to the flow of the load current or KZ via the electric arc; with increasing contact resistance between the wire and contact inserts of the current receiver; The presence of ice; closure by poloz, the current receiver of the non-well-specific branches of the insulating interface of the anchor sites and others.
The main measures of preventing facing wire are: improving the sensitivity and speed of protection against CW currents; Application on the EPS blocking that prevents the rise in the current receiver under load and forcedly turning it off when lowering; equipment of insulating interfaces of anchor sections with protective devices that contribute to the arc gash in the zone of its possible occurrence; Timely measures preventing ice deposits on wires, etc.
Bearing cable
The carrier cable is a chain suspension wire attached to supporting contact network devices. The contact wire is suspended to the carrying cable with the help of strings - directly or through auxiliary cable.
On domestic w. D. on the main paths of lines electrified on constant current, as a carrier cable is used mainly copper wire with a section of 120 mm2, and on the side of the stations -stable (70 and 95 mm2). Abroad on alternating current lines also use bronze and steel cables with a cross section from 50 to 210 mm2. The cable tension in a semi-perched contact suspension varies depending on the ambient temperature ranging from 9 to 20 kN, in a compensated suspension, depending on the brand of the wire - within 10-30 kN.
String
The string is the element of the chain contact suspension, with which one of its wires (as a rule, contact) is suspended to another - carrying cable.
The design distinguish: link strings made up of two or more ball-nirno related links of rigid wire; Flexible strings of flexible wire or kapron rope; rigid - in the form of spacers between wires used much less often; looped - from wire or metal strip, freely suspended on the top wire and rigidly or hinged in the string clips of the lower (usually contact); Sliding strings fixed on one of the wires and moving along the other.
On domestic w. D. The greatest distribution was obtained links of bimetallic graded wire with a diameter of 4 mm. The disadvantage of them is electric and mechanical wear in the articulations of individual units. In the calculations, these strings are not considered as conductive. Flexible strings made of copper or bronze stranded wires are devoid of flexible strings, which are rigidly attached to string clamps and performing the role of electrical connectors distributed along the contact suspension and not forming substantial focused masses on the contact wire, which is typical for typical transverse electrical connectors used at links and other non-conductive strengtimes. Sometimes the non-conductive strings of the contact suspension from the Kapron Rope are used, which require transverse electrical connectors to attach.
Sliding strings capable of moving along one of the wires are used in semi-permanent chain contact pendants with a small structural height, when installing sectional insulators, in places of anchoring of the carrier cable on artificial structures with limited vertical dimensions and in other special conditions.
Rigid strings are usually installed only on the contact network air arrow, where they perform the role of the lifting limiter of the contact wire of the same suspension relative to the other wire.
Enhancement
Enhancement wire - wire electrically connected to a contact suspension, which serves to reduce the overall electrical resistance of the contact network. As a rule, the reinforcing wire is suspended on the brackets from the field side of the support, less often - above the supports or on consoles near the carrier cable. The enhancement wire is used in areas of direct and alternating current. Reducing the inductive resistance of the AC contact network depends not only on the characteristics of the wire itself, but also from its placement relative to the contact suspension wires.
The use of reinforcing wire is provided at the design stage; As a rule, one or more multi-voltage wires of the type A-185 are used.
Electric connector
The electrical connector is a segment of the wire with conductive reinforcement, designed to electrically connect the wires of the contact network. There are transverse, longitudinal and bypass connectors. They are performed from uninsulated wires so that they do not interfere with the longitudinal movements of the wires of contact suspension.
Transverse connectors are installed for parallel compound All contact network wires of the same path (including reinforcing) and at stations for contact suspension of several parallel pathways included in one section. The transverse connectors are mounted along the path at distances depending on the current and proportion of the cross-section of contact wires in general section of the contact network wires, as well as from the operation modes of the EPS on specific traction shoulders. In addition, the connectors are placed at starting and overclocking places of the EPS.
Longitudinal connectors are installed on air arrows between all the wires of contact suspensions that form this arrow, in the places of interchangeable sections - on both sides with uninsulant pairing and on the one hand, the insulating pairings and other places.
Obvoable connectors are used in cases where the interrupted or decreasing cross section of the contact suspension is required due to the presence of intermediate anchors of reinforcing wires or when the insulators is turned on to the carrier cable for passage through an artificial structure.
Fittings of the contact network
The fittings of the contact network - clips and parts for connecting the contact suspension wires with each other, with supporting devices and supports. Armature (Fig. 8.15) is divided into stretch (butt, end clamps, etc.), suspended (string clamps, saddles, etc.), fixing (fixing clamps, holders, ears, etc.), conductive, mechanically loaded (clamps Feeding, connecting and transition - from copper to aluminum wires). Products included in the reinforcement, in accordance with their purpose and production technology (casting, cold and hot stamping, pressing, etc.) are performed from carpet cast iron, steel, copper and aluminum alloys, plastics. The technical parameters of the valves are regulated by regulatory documents.
The energy consumed by rail is spent on ensuring the traction of trains and nutrition of non-step consumers: stations, depot, workshops, train control devices.
The power supply system of electrified railways includes power plants, district transformer substations, networks and power lines, which are called external power supply. The internal or traction power supply includes traction substations and an electrical network.
The power plants produces a three-phase alternating current with a voltage of 6 ... 21 kV with a frequency of 50 Hz. On transformer substations, the current voltage increases to 750 kV, depending on the range of electrical energy transmission to consumers. Near the electricity consumption places, the voltage is reduced to 110 ... 220 kV and served in the district networks, which are connected to the traction substations of electrified railways and transformer substations of roads with diesel drive.
The traction network consists of contact and rail wires, which are respectively nourishing and suction lines. Plots of the contact network are connected to neighboring traction substations.
On railways, direct current systems with a rated voltage of 3000 V and single-phase alternating current with a nominal voltage of 25 kV of 50 Hz are used.
The main parameters characterizing the power supply system of electrified railways are the power of traction substations, the distance between them and the contact suspension area.
Traction DC substations perform two functions: reduce the voltage of the summed three-phase current and transform it into a permanent one. The voltage level on the electrical composition of the electrical composition at a constant current on any block plot should be no more than 4 kV and at least 2.7 kV, and at some time it is allowed not less than 2.4 V. Taking into account these requirements, direct current traction substations are placed nearby from each other (10 ... 20 km) with the maximum allowable cross section of the contact wire.
AC traction substations are used only to reduce the voltage of AC (up to 27, 5 kV) derived from energy systems. In directions electrified by alternating current with a nominal voltage of 25 kV, the distance between the traction substations is 40 ... 60 km. The cross-sectional area of \u200b\u200bthe contact network wires in a system of single-phase alternating current is about two times less than at a constant current. However, the design of locomotives and electric trains with alternating current is more complicated, and their cost is higher.
Docking contact networks of electrified lines on different current systems is carried out at special railway stations.
The contact network is a combination of wires, structures and equipment that ensures the transmission of electrical energy from traction substations to electric rolling stock current collectors.
The contact network consists of consoles, insulators, carrier cable, contact wire, locksters and strings and mounted on metal or reinforced concrete supports (Fig. 22.1).
Simple (in secondary station station and depot) and chain air contact networks are used. A simple contact suspension is a free hanging wire, which is fixed on the supports. In the chain suspension (Fig. 22.1), the contact wire is suspended between the supports is not free, but is attached to the carrying cable using wire strings. Due to this, the distance of the honey surface of the head and the contact wire remains almost constant. The distance between the supports during the chain suspension is 70 ... 75 m.
The height of the contact wire above the surface of the rail head on the distillation and stations should be at least 5750 mm, and on the move - 6000 ... 6800 mm.
The contact wire is made of a solid-state electrolytic copper of a special profile (Fig. 22.2). It can have a cross-sectional area of \u200b\u200b85, 100 or 150 mm2.
Contact network supports are used reinforced concrete (up to 15.6 m height) and metal (15 m or more). The distance from the axis of the extreme way to the inner edge of the supports on the distillations and stations should be at least 3100 mm. On existing electrified lines and under difficulty conditions, the specified distance is allowed to 2450 mm - at stations and up to 2750 mm - on distillation.
To protect the contact network from damage, it is partitioned (separated into separate sections - sections) with the help of air intervals (insulating pairs), neutral inserts, sectional and mortise insulators.
Airbags are arranged for electrical insulation of adjacent sections from each other. The air gap is carried out in such a way that with the passage collector of the electrically movable composition, the mating areas are electrically connected. At the borders of the air intervals, install contact network supports having a distinctive color.
A neutral insert is called a plot of a contact network, which constantly absent current. Neutral insert is a few successively included air gaps and during the passage of the electro-labeled composition provides electrical insulation of conjugated areas.
Terminations, intermediate stations, groups of paths in station parks are isolated into separate sections. The connection or disconnection of sections is carried out by sectional disconnectors placed on the contact network supports or using partitioning posts. Partitioning posts are equipped with protective equipment - automatic switches from short circuits.
To ensure the safety of attendants and other persons, all metal structures (bridges, overpasses, traffic lights, hydrocolones, etc.), directly interacting with the elements of the contact network or in a radius of 5 m from them, ground or equip the disconnect devices. Also in the zone of influence of the contact network, all underground metal structures are isolated from the ground to protect them from damage to the wandering currents.
Contact Network Device: 1 - Support; 2 - thrust; 3 - console; 4, 9 - insulators; 5 - carrier cable: 6 - contact wire; 7 - string; 8 - Lock
A set of devices for transmitting electricity from traction substations to EPS through current receivers. The contact network is part of the traction network and for rail electrified transport usually serves its phase (with alternating current) or pole (with constant current); Another phase (or pole) is a rail network.
The contact network can be made with a contact rail or contact suspension. The running rails were first used to transmit electricity a moving crew in 1876 by the Russian engineer F. A. Pyroatsky. The first contact suspension appeared in 1881 in Germany.
The main elements of the contact network with contact suspension (frequently called air) are the wires of the contact network (the contact wire carrying the cable, enhancing the wire, etc.), supports that support devices (consoles, flexible crossbars and rigid crossbars) and insulators. Contact chain contacts are classified: by type of electrified transport, for which the contact network is intended, - a trunk, including high-speed, J.-D., tram and career transport, mine underground transport, etc.; by the nature of the current and the rated voltage of the EPP feed from the contact network; on the placement of contact suspension relative to the axis of the railway-for central (main railway transport) or lateral (industrial transport) current; by contact suspension types - contact networks with a simple, chain or special suspension; According to the features of the implementation - contact networks of distillation, stations, for arts, structures.
In contrast to other power supply devices, the contact network has no reserve. Therefore, the reliability of the contact network impose increased requirements, with 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 area of \u200b\u200bthe wire cross sections The contact network is usually carried out when designing a traction power supply system. All other issues are solved with the help of the theory of contact network-independent scientific discipline, the establishment of which in many ways contributed to the works of owls. Scientist I. I. Vlasova. Based on design issues The contact network is: the choice of the number and stamps of its wires in accordance with the results of the calculation of the traction power supply system, as well as traction calculations, select the type of contact suspension in accordance with Max, the speeds of the EPS movement and other conditions of the current; determining the length of the span (mainly by the condition for ensuring its wind resistance); Selection of support types and support devices for distillers and stations; Development of designs Contact network in arts, facilities; Placement of supports and drawing up plans Contact network of stations and distances with coordination of wiring zigzags and taking into account the performance of air arrows and elements of partitioning of the contact network (insulating interfacing of anchor sections, sectional insulators and disconnectors). When choosing construction and installation methods, the contact network in the course of electrification of the railways tend to significantly reflect on the transportation process at unconditional provision high Quality work.
Basic production, enterprises for the construction of contact network - construction and installation trains and electrical train. The organization and methods of maintenance and repair of the contact network are selected from the conditions for ensuring a given high level of reliability of the contact network with the smallest labor and material costs, the safety of workers of the contact network of the contact network, less influence on the organization of trains movement. Production, enjoyment of the contact network is the power supply distance.
Main dimensions (see Fig.), Characterizing the placement of the contact network relative to other post, devices. d., - Height of hanging the contact wire above 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 are: PKS - contact network wires; O - Support of the contact network; And - insulators.
distance A from parts under stress to grounded parts of structures and rolling stock; Distance from the axis of the extreme way to the inner edge of the contact network support at the level of rail heads.
Improving the designs of the contact network is aimed at improving its reliability while reducing the cost of construction and operation. J.-B. The supports of the contact network and the foundations of the metal supports are carried out taking into account the electrocorrosive impact on their immature of wandering currents. An increase in the service life of the contact wire is achieved, as a rule, using coal contact inserts on current users.
For maintenance Contact network on domestic w. With no tension removal, insulating removable tower, mounting automotive machines are used. The list of works performed by voltage was expanded due to the use of double insulation on flexible crossbars, in the anchors of wires and other elements of the contact network, many control operations are carried out by means of their diagnostics that are equipped with laboratory wagons. The operational of switching sectional disconnectors of the contact network has increased significantly due to the use of television management. Equipment of power supply distance with specialized mechanisms and machines for the repair of the contact network (for example, to dig meat and install supports).
Increased reliability of contact networks contribute to the use of ice melting methods developed in our country, including without interruption of trains, electrivatelent protection, wind-resistant diamond-free contact suspension, etc. To determine the number of areas of contact networks and the boundaries of service sections, use the concepts of operational length and deployed The length of electrified paths equal to the sum of the lengths of all the anchor sections of the contact networks at the specified limits. On domestic railways, the deployed length of electrified paths is an accountable indicator for the K. e., Power supply distances, road separations, and more than 2.5 times higher than the operational length. Determining the need for materials on the repair and operational needs of contact networks is made by its deployed length.
The contact network is a special power line, which serves for the supply of electrical energy to the electro-rigging composition. Its specific feature is that it should provide a current-moving electric locomotive. The second specific feature of the contact network is that it cannot have a reserve. This causes increased demands on the reliability of its work.
The contact network consists of a contact suspension path, the contact network supports that support the contact network of devices in the wirespace. In turn, the contact suspension is formed by the wiring system - carrier cable and contact wires. For DC thrust system, there are usually two contact wires in the suspension and one for an AC thrust system. In fig. 6 shows a general view of the contact network.
The traction substation supplies electricity the electro-moving composition through the contact network. Depending on the connection of the contact network with traction substations and between the contact suspensions of other paths of the multiplinary section, the following schemes differ within the boundaries of the individual intermetunction zone: a) once a delta double-sided; 
Fig. 1. General view of the contact network
b) nodal; c) parallel. 
but) 
in)
Fig. 2. The main power schemes of contact suspension paths a) - separate; b) - nodal; B) - parallel. PPS-points parallel connecting contact suspension of various paths; PS - post partitioning; TP - Tracting substation
Separate bilateral scheme - the power supply diagram of contact suspension, in which the energy into the contact network comes from two sides, (adjacent traction substations operate in parallel to the traction network), but the contact suspension is electrically connected to each other in the intermetunction area boundaries. Scope of such a scheme - Power supply of electrical railway With unplaced intermetractation zones and relatively uniform power consumption in directions.
The node scheme is a diagram differing from the previous presence of an electrical connection between paths of paths. Such a connection is carried out using the so-called contact network partitioning posts. The technical equipment of the partitioning of the contact network allows, if necessary, to eliminate not only the transverse connection between the suspensions of paths, but also a longitudinal, breaking the contact network within the intermetraction zone boundaries into separate electrically unnecessied sections. This significantly improves the reliability of the driving power supply system. On the other hand, the presence of a node in normal modes allows you to more efficiently use the contact network of paths for transmitting electrical energy to the electrical composition, which gives substantial energy savings during uneven power consumption in directions. Consequently, the scope of such suspension is the sections of the electric railway with extended intermetosnation zones and significant uneven power consumption in directions.
The parallel diagram is a diagram, differing from the nodal circuit, a large number of electrical nodes between the contact suspension paths. It is used with even greater unevenness of electricity consumption in paths. Such a scheme is especially effective when driving heavy trains.
Topic: What voltage is supplied to the railway contact network, the power supply of the railway.
Railway transport consumes about 7% of electricity, which is produced by electric stations in Russia. For the most purpose, it is spent on the movement of trains (their craving), as well as real estate objects (depot, stations, workshops and system regulation systems of the railway transport). In addition, near the power supply system of railways can be connected near her located settlements (small) and industrial enterprises. The power supply system of railways (electrified) consists of the outer part (electrical stations, transformer electrical substation, power grid and power lines electrical gear) and traction (traction substations and the electric grid).
At electric stations (thermal, atomic, aqueous) produce a three-phase variable electrical current of the value of 6-21 kV voltage and a standard frequency of 50 Hz. To transmit the electricity, the substations voltage increases to 750 kV (the value depends on the distance between the station and the consumer). Near the consumers themselves, electrical energy voltage is reduced to 110-220 kV and are issued to district power grids, which are also connected to the traction electrical sheets of railways (electrified) and electrical substations of roads with fuel (thermal).
Any violation of the normal power supply of railways leads to interruptions in the planned movement of rolling stocks. In order to qualitatively ensure reliable power supply of the traction power grid of the railway transportation, usually, it is possible to provide its electrical connection to two different sources of electricity in advance. Sometimes it is allowed to power from 2 monotonal power supply lines or one two-chart.
Plots of the electrical contact network are powered from adjacent traction electrodesters. This makes it possible to more evenly load the traction electrical substations and the contact power grid, which contributes to the decrease in the various losses of electrical energy in the traction electrified network.
As you know, in Russia on railways, 2 power supply systems are used: alternating single-phase current and permanent. Electric thrust on the variable three-phase current did not receive practical distribution, as it is technically very difficult to isolate (protect) located closely the power wires of two different phases of the contact power grid (the third phase is the rails themselves).
The rolling stock (electrical) is provided by special DC electric motors, since the proposed models of AC motors do not meet certain requirements for reliability and power. For this reason, the railway line is supplied with a system of alternating single-phase current, and on the compositions themselves (locomotives) put special electrical equipment, which converts alternating single-phase current into constant.
The rated values \u200b\u200bof the voltage supplied to the current collectors of the movable electrical composition are regulated: 25 kV - with alternating current and 3 kV - with constant. In this case, there are permissible oscillations of electrical stress: with alternating current - 21-29 kV and with constant - 2.7-4 square meters. At certain sites, the level of electrical voltage of at least 19 kV with alternating current and 2.4 kV at constant can be allowed.
On electrified railways operating on a constant current, the power traction electrodesters perform 2 tasks: reduce the three-phase current voltage and transform it into a permanent one. All electrical equipment that supplies an alternating electric current is located in the open space, and the power rectifiers and additional systems are indoors. From the traction electrodests, the energy enters the contact power grid along the coal line, which is called the feeder.
P.S. The power supply of the railway is due to its peculiarities due to the specifics of this transport itself. In different areas and for various vehicles, rational use of its type of electric current and voltage values. This is how maximum efficiency and reliability of electricity supply of railway transport.