Electrical supply infrastructure is designed to serve consumers directly from energy sources. The latter can be both autonomous generators and full-fledged thermal, hydrological and nuclear power plants. At the same time, backbone networks are rarely used to power end consumers. The distribution of energy for the supply of transport hubs uses a traction substation with characteristics suitable for a particular facility.
Substation device
The technical support of the substation in most cases is focused on receiving electricity of the order of 110-220 kV. There are also low-power installations designed for networks with a voltage of 35 kV. Depending on the potential, they can have from 2 to 6 entry points - these are small dead-end stations that are part of the structure of one complex. Step-down transformers and converters are responsible for power distribution. And not necessarily switchgear should be responsible for the supply of energy to consumers. Some of them work to maintain the efficiency of local facilities. In addition, the device of traction substations provides for the presence of inverters and rectifiers. Their tasksare reduced to rectifying the current for the needs of a particular consumer. They can also provide a return to the general network of energy that is generated as a result of regenerative braking of the local line. Feeder installations are used to ensure communication between the distribution infrastructure of the substation and consuming objects.
Varieties
One of the basic classifications involves the division of substations according to the method of connecting to the main power supply line. In particular, nodal, end and intermediate objects are distinguished. Nodal support the reception and distribution of energy in three channels in the range of 110-220 kV. They can also act as a current source for other traction stations. End objects work with two lines, and intermediate objects are designed to connect a divided circuit - between an energy source and the same substation. According to the electric traction system, stations of direct and alternating current are distinguished. The differences between them are that the DC traction substation is necessarily equipped with switchgear. AC units serve networks with a voltage of about 27 kV and can be installed at distances of up to 50 km from each other.
Substation applications
The main use of traction distribution substations is electrified transport and related infrastructure. The basis of the sources of such energy supplymake up stations that distribute direct current. They are installed along transport lines and provide energy for electric locomotives, trolleybuses, trams and railway complexes. In turn, AC traction substations are more often used to service telemechanics and automation, which are part of the same infrastructure. For example, it can be signal arrows, traffic lights and communication lines. This does not mean at all that a less responsible task falls on the AC station. In terms of power potential, they lose to analogues with direct current, but their energy potential is more stable and resistant to loads.
Substations for railways
Most of these types of facilities serve railway tracks. They serve for distribution, transformation and direct power supply of electric rolling stock and non-railway consumers. Installations for direct current distribution are mounted along lines with a distance of about 10-15 km. This interval may vary depending on the congestion of the tracks and their purpose. The source of energy is also external main networks, after which the energy is sent to the transformer. This is followed by the conversion stage, after which the electricity is sent to the contact network. It is important to note that the railway traction substation is characterized by large amounts of regenerative braking energy. That is, there is a need to organize technical means that can also stably transport energy back to the main highways. This task is performed by inverters - as a rule,through contact network switches in automatic mode.
Complete equipment
In addition to the main electrical filling in the form of converters, rectifiers and other devices serving the contact network, substations are supplemented with protective equipment and fire-fighting equipment. Moreover, these funds are required not only for local maintenance of protective functions, but also to ensure the possibility of providing first aid. The protective equipment of traction substations may include relay devices, circuit breakers, signaling equipment, etc. The structure of modern substations has sensors that record the facts of overloads, overheating and failure of individual telemechanics segments.
Substation operation
Substations can be controlled in several ways. Modern objects of this type are serviced through remote controls or using automated equipment. The traditional method of control through personnel is also used. This control method is more often used at small stations in small towns - due to the impossibility of organizing automated support. However, large metropolitan areas can also be supplied by a traction substation with direct service by personnel due to the risk of their emergency shutdown. In order to increase reliability, a combined control scheme is used, which also involves automated tools withremote control, and staff. In this case, all processes are monitored by an observer controller who takes action regardless of automation in emergency situations.
Substation Maintenance Manual
Maintenance is carried out in accordance with the site-specific preventive inspection schedule. A typical set of activities included in the maintenance program includes equipment revision, test work, fixing minor problems and identifying problem areas that will be examined in more detail during a scheduled repair. For a long-term perspective, as part of the state of the equipment, a log is kept that records the dynamics of the results of the check. Without fail, when performing preventive maintenance, traction transformer substations are cleaned from pollution, consumables are updated in some areas and more modern equipment is installed.
Repair work
At the time of the overhaul, the responsible person receives a document indicating the results of previous tests. Based on his analysis, the engineer makes a conclusion indicating the problem areas where repair operations will be carried out. At the basic level, bolted, contact and welded connections are updated. When performing current repairs, the attachment points are restored, cracks in the insulation are eliminated, seals and seams are reinforced. In extremecases, the traction substation may be reconstructed with the replacement of the main equipment. Typically, such events are carried out after changing the network parameters, when the voltage values \u200b\u200bare increased or decreased. Modernization is also widespread as part of expanding the range of station tasks.
Conclusion
Today, traction power distribution facilities are the best tool for supplying transport infrastructure. First of all, this concerns the railway tracks. A traction substation connected to a stable external network is able to serve several consumers at once, including distribution equipment. In terms of technology upgrades, these are flexible objects that allow you to make changes to both the hardware infrastructure and management tools. The most modern traction kits support full automated control, which reduces the cost of their operation and maintenance.
