Contact network - what is it? Features of the contact networks of the railway, tram or trolleybus

The infrastructure of the rolling stock must necessarily include contact networks. Due to this provision, the supply of target pantographs is realized, which, in turn, set the vehicles in motion. There are many types of such networks, but all of them are a set of cables fixing and reinforcing elements providing power from electrical substations. Also, the contact network is also used for servicing fixed objects, among which are various crossings and lighting stations.

General information about contact networks

This is part of the technical structure, which is part of the complex of electrified roads and roads. The main objective of this infrastructure is the transfer of energy from the traction substation to the electric rolling stock. In order to provide the possibility of supplying equipment with energy from several substations, the contact network is divided into several sections. Thus, sections are formed, each of which feeds a separate feeder from a particular source.

Sectioning is also used to facilitate repair operations. For example, if the line is damaged, the transmission of energy will be stopped only in one section. Defective wiring, if necessary, can be connected to a working substation, which will shorten downtime. In addition, the contact network of railways is provided with special insulators. This solution is due to the fact that the accidental formation of an arc at the time of passage of current collectors can disrupt the main envelope of the wires.

Device of contact networks

Networks of this type represent a whole complex of components of the electrical infrastructure. In particular, a typical device of this structure includes power cables, special suspensions, reinforcement and its special parts, as well as support structures. To date, the instruction is applied, according to which the details, the fittings of the contact network and the wires go through a special procedure of thermal diffusion galvanizing. Elements of low-carbon and carbon steel are subjected to protective treatment to improve the strength and durability of communications.

Features of air contact nets

Air networks are most common due to space saving and more efficient organization of electric lines. However, there are also disadvantages of such a device, which are expressed in higher costs for installation and maintenance. So, the air contact network includes a supporting cable, reinforcement, wires, arrows with intersections, and also insulators.

The main design features of networks of this type are reduced to the method of placement. Communications are suspended on special supports. There may be sagging of wires between the points of the installation. Completely eliminate this flaw is not possible, but its presence can cause damage to power lines. For example, if the support of the contact network allows a strong sag, then the current collector moving along the cable can lose its connection with its line in the places of suspension.

Contact networks of railways

In this case we are talking about the classic performance of the contact network. It is the railways that use the largest amounts of materials for the electrification of rolling stock. The wire itself for such purposes is made of electrolytically hard copper with a cross-sectional area of up to 150 mm ² . As for supporting elements, the contact network of railways is provided with reinforced concrete or metal installations, whose height can reach 15 m. The gaps from the axis of the outermost tracks to the outer sides of the supports at stations and distances are no more than 310 cm. However, there are exceptions - for example, Difficult conditions, the technology allows for a gap of up to 245 cm. Methods for protecting this type of wire are traditional - splitting into individual areas, the use of insulators and neutral inserts.

Contact network of the trolleybus

Compared to rail transport, the trolleybus movement does not involve a permanent electrical connection with the surface. Also, the requirements for maneuverability are increasing, which causes changes in the organization of the electrification infrastructure. These differences and determined the main feature of power grids for trolleybuses - the presence of two-wire lines. In this case, each wire is fixed with small gaps and is provided with reliable insulation. As a result, the contact network becomes more complicated both in the straight sections and in the zones of ramifications and intersections. The wide application of sectioning with the appropriate insulators can also be attributed to the features. But in this case, the sheath not only protects the wires from the contacts between them, but also protects the material at the intersections. In addition, in the infrastructure of trolleybus networks, the use of arc current collectors and pantographs is not allowed.

Contact networks of trams

In tram-net contact networks, copper wires and similar alloys are usually used. Also, the possibility of using steel-aluminum wires is not ruled out. The coupling of sections with different suspension heights is performed with a slant of the wiring relative to the longitudinal profile of the track. The deviation can vary from 20 to 40%, depending on the complexity and conditions of the line laying site. On straight sections, the tram network is zigzagged. In this case, the step of the zigzag - regardless of the type of suspension - does not exceed four spans. It should also be noted the amount of deviation of the contact cables from the axis of the current collector - this value, as a rule, is no more than 25 cm.

Conclusion

Despite the technological development of electrification systems, contact networks in the basic design options retain the traditional device. Changes in terms of improving the technical and operational parameters affect only some aspects of the application of parts. In particular, the contact network of railways is increasingly supplied with elements that have passed through thermal diffusion galvanizing. Additional processing of the element base undoubtedly increases the reliability and longevity of the lines, but it contributes to a minimal degree to radical technical improvement. The same applies to tram and trolleybus electric grids, in which, of course, latching devices, strength of reinforcement and parts of suspended structures have been significantly improved lately.