RU46979U1 - DEVICE FOR ELECTRIC SUPPLY OF NON-TRAFFIC CONSUMERS OF ELECTRIFIED RAILWAYS - Google Patents

Abstract

The utility model relates to the field of power supply to non-traction consumers of electrified railways and contains a three-phase power transformer, the primary winding of which is connected to the buses of the regional winding of the traction transformer and connected to its secondary winding with a nominal voltage of 27.5 kV, a three-phase three-wire longitudinal power supply line operating in isolated by neutral and located on the field side of the contact network supports. The utility model makes it possible to reconstruct the DPR system, while maintaining a huge array of existing equipment and the ability to transmit the required power at a voltage of 27.5 kV, improve electrical safety conditions in electrical installations with a metal connection to the rail network, and improve the safety conditions for train traffic by disabling the mandatory direct metal communication with signal rail circuits of equalizing circuits of grounding devices of KTP, which are a source of transverse asymmetry for global current.

Description

The utility model relates to the field of power supply to non-traction consumers of railways and can be used to improve the quality of electricity during power supply of railway automation and telemechanics (ZhAT) devices from high-voltage longitudinal power supply lines (VL PE) located on the supports of the contact network, as well as to increase electrical safety at maintenance of electrical installations of non-traction railway consumers.

Known systems for power supply of railway automation and telemechanics devices and other non-traction consumers of railway transport from high-voltage lines located on the supports of the contact network. In areas with AC electric traction, the most common is the three-phase “two wires-rail” system (DPR), consisting of two phase “A” and “B” wires connected to a bus with a voltage of 27.5 kV of the traction substation. The third phase “C” in the DPR system is the rail network. An upgraded version of this system is the system proposed in the patent for utility model No. 42484, characterized in that the third wire (phase "C") is also laid along the supports of the contact network.

In some areas, three-phase systems with insulated neutral voltage of 6 (10) or 35 kV are used for power supply of non-traction consumers and backup power supply of ZhAT.

The disadvantage of the DPR is that the system with large earth fault currents. At a point of earth or rail

there is a potential reaching 3.5 kV, which falls into the ZhAT devices, into the system of neutral conductors of the low-voltage network and on grounding devices having a metal connection with the rails. The consequence of leakage of large overcurrents and overvoltages along the rail network as a natural grounding conductor is damage to equipment at low-voltage consumers of the DPR network and a decrease in electrical safety conditions when working on railway tracks and in ZhAT devices.

Almost all complete transformer substations (KTP) designed for backup power supply of ZhAT devices have leveling circuits of grounding devices connected to the rail network. The presence of a large number of these equalizing circuits with non-normalizing resistance to the spreading current creates additional transverse asymmetry in the electrical signal rail circuits. This reduces the reliability of the operation of the HEAT and the safety of train traffic.

Another disadvantage of the DPR system is its longitudinal and transverse asymmetry. The consequence of this is that it is a source of strong electromagnetic radiation, and from the electromagnetic radiation of the AC traction network, voltage asymmetry appears in it itself.

In the system proposed in patent No. 42484, the voltage unbalance caused by the electromagnetic influence of the traction network is reduced, since all three phase conductors are located on the supports of the contact network. However, it remains a system with high earth fault currents and unsatisfactory electrical safety conditions.

In three-phase three-wire networks with isolated neutral with a voltage of 6 (10) kV, there are no feeder zones 40 ... 60 km long

the ability to transfer sufficient power with permissible voltage deviations. In areas with alternating current electric traction in the conductors of the overhead power lines of the ZhAT power supply, the level of voltage induced from the contact network is comparable with the phase voltage of these lines. This creates a large number of false positives against single-phase earth faults.

The disadvantage of overhead lines located on the supports of a contact network with an operating voltage of 35 kV in railway conditions is the need to strengthen the class of insulation of the line, the use of additional insulators in hanging garlands. This makes the construction of these overhead lines more expensive and creates difficulties when operating in the confined space of railway lines.

Another disadvantage of overhead lines with a voltage of 35 kV is the large distributed capacitive power. With a small active load of consumers distributed along the overhead line, and the presence of a large number of switched-on ZhAT backup power transformers in idle mode, the presence of a significant capacitive power creates the conditions for the occurrence of resonant phenomena and emergency conditions.

The purpose of this proposal is to create a device for power supply of non-traction consumers and ZhAT devices of railways, which will make it possible to use existing equipment of the three-phase DPR system for a voltage of 27.5 kV, reduce the current of a single-phase earth fault, and in the low-load mode of consumers, reduce the likelihood of resonance phenomena, to ensure that the full length of the feeder zone is sufficient for railway non-traction consumers with acceptable voltage deviations, and at the same time m get rid of the mandatory connection to the rail network of equalizing circuits KTP.

The essence of the proposed device is illustrated by the attached figure (see Fig. 1), which shows a diagram of the proposed device.

At the traction substation of alternating current, traction transformer 1 has two secondary three-phase windings, traction and district. Phase "A" 2 and phase "B" 3 of the traction winding with a voltage of 27.5 kV are connected to the feeders of the contact network and the two conductors of the DPR 5 system. Phase "C" is connected to the rail network. Feeder 7 of other non-traction consumers of the substation are connected to the buses of the regional winding.

In this utility model, it is proposed to connect the primary winding of the power three-phase transformer 8 to the regional winding of the traction transformer, and from the secondary winding with a voltage of 27.5 kV, power the three-phase three-wire high-voltage line of longitudinal power supply 9, operating in an isolated neutral mode and located on the supports of the contact network obtained by supplementing the two conductors of the DPR with a third conductor isolated from earth, while on the transformer substation having all the high-voltage leads of the primary winding at yazhenie 27.5 kV, phase "C" rail is disconnected from the network and connected to the third overhead conductor PE.

Claims (1)

A device for powering non-traction consumers of electrified railways, including a three-phase power transformer and a three-phase three-wire high-voltage line connected to its secondary winding with an operating interphase voltage of 27.5 kV, characterized in that for using the existing equipment of the "two wires - rail" system ( DPR), to increase electrical safety, reduce the influence of grounding devices of power supply on electrical signal rail circuits, this device works according to the system a tank with insulated neutral and the primary winding of the step-up transformer is connected to the regional winding of the traction transformer.