SU656887A1 - Arrangement for power supply of a.c. contact wire network - Google Patents

Description

one

The invention relates to the field of electricity and can be used in power supply systems for traction consumers of trunk and quarry railways electrified on single-phase alternating current.

A device for power supply of an AC contact network containing contact wires with neutral inserts and rails of even and odd directions is known, including traction connections with two traction transformers with a connection circuit for windings L 1, and the terminals of the primary windings of adjacent transformers the traction substations are connected to the mains in such a way that the alternation of their phases is different, and the secondary windings of the traction transformers are connected to the wires of the contact network and the rails one .

The connection of transformers according to the scheme Ad provides the alternation of the loaded phases of the power transmission lines, with the phases of the traction transformers of the neighboring traction substations alternating, and the traction transformers within one

As a result, the substations have the same phase connection on the high and low sides of the transformers.

The connection groups of the traction transformers are selected in such a way that the negative-sequence current vectors in the supply network from adjacent substations are mutually shifted by 120 °.

With the total number of traction substations, a multiple of three, and continuous or reverse alternation of the connection phases of the transformers of the mixed traction substations, a certain symmetrical effect in the supply network is provided.

However, the known power supply device does not provide a sufficiently symmetrical effect due to the inequality of the loads of the traction transformers and the mutually independent and random nature of these loads, which adversely affects the work of individual consumers, synchronous generators, and does not provide the required quality of electrical energy.

Claims (2)

The aim of the invention is to increase the efficiency of balancing the supply network. The goal is achieved by the fact that in the device for the power supply of an AC contact network, the terminals of the primary windings of the traction transformers within the same substation are connected to the mains supply with different phase alternation, providing a reverse sequence current in the mains supply by 120 °. and the secondary windings of transformers of one substation are connected: one -4 contact network of even direction, and the other to the contact network of odd direction, while the contact network of even and odd directions is electrically separated, and in places of electrical connection of contact wires of even and odd directions to one of The contact wires are fitted with additional neutral inserts. In addition, additional neutral inserts can be installed in the contact wires of even and odd directions on the stretch. The alternation of the phases of the traction transformers of the neighboring traction substations is preserved in this case, but it is carried out separately for even and odd directions. For the separation of the power of the contact network of even and odd directions, additional contact inserts are provided in the contact network of one of the directions at the junction points of the even and odd paths. In case one of the transformers is disconnected, the power supply of the overhead contact network can be supplied to the console from the transformers of neighboring traction substations. It is possible to install a third backup transformer at a traction substation. Depending on the group and the switching on circuit of the disconnected transformer, the connection circuit of the backup transformer should be changed in accordance with the backup transformer circuit. If there are additional neutral inserts in the overhead contact network, the need to install a third backup transformer or supply the overhead contact network from the transformers of neighboring traction substations when one of the transformers of the traction substation is disconnected. In this case, when one of the transformers is disconnected, the power supply of the even and odd directions of the contact network is temporarily produced from a SINGLE transformer. At the same time, by changing the installation location of additional neutral inserts on the spans, it is possible to change the distribution of load currents of the shoulder traction transformers and, thereby, increase the balancing effect of the cyclic alternating connection of the phases of the traction transformers. In the proposed device, when balancing the power supply mode, the negative sequence current of each traction substation is divided into two components of the current — from even and odd directions / {; these two components of the negative sequence current are shifted mutually by 120 °, which provides an additional balancing Effect. FIG. 1 is a schematic diagram of a device for power supply of an AC contact network; in fig. 2 - vector diagrams of negative sequence currents and sequence of alternating types of switching on transformers in the proposed device; in fig. 3 - an additional neutral insertion in the contact network of one of the directions at the joints of the even and odd paths. The scheme contains a three-phase AC power line 1, a three-phase traction transformer .2 connected according to the scheme А Д, a traction substation 3, an even directional contact network 4, an even-direction rail 5, an oddly directional contact network 7, additional neutral insert 8. FIG. Figure 2 shows the cyclicality of phase alternation (denoted 1tz, d, Ilntu and 1HT1 when connecting transformers to the contact network of even direction 9; cyclicality of alternation of phases when connecting traction transformers to contact network of odd direction 10; negative current vector currents of the transformers 11 supplying an even direction; current vectors. a reverse sequence of the current transformers 12 supplying an odd direction (vectors II and 2 are for the high voltage side); total vectors then The reverse sequence of the power supply network 13. From the comparison of the vector diagrams (Fig. 2), it is clear that the total negative sequence currents from each traction substation in the proposed device are 2 times less than in the known device. The proposed device allows to significantly reduce the currents and negative sequence in the supply network, reduce energy losses from negative sequence currents. In addition, the implementation of the invention requires less cost compared to devices providing illogical balancing effect. When using the invention, the asymmetry coefficient in the supply network decreases 1.6-1.7 times as compared with the asymmetry factor of the known device. Claims. A device for power supply of an alternating current contact network containing contact wires with neutral inserts and rails of even and odd directions, including traction substations with two traction transformers with an L / 4 connection circuit, the outputs of the primary windings of which are connected to the mains, and The secondary windings of which are connected to the wires of the contact network and rails, characterized in that, in order to increase the efficiency of balancing the supply network, the conclusions of the primary windings of the traction transformers in within one substation, they are connected to the mains with different phase alternations. providing a shift of negative sequence currents in the supply system by 120 °, and the secondary windings of transformers of one substation are connected; one to the contact network of the even direction, and the other to the contact network of the odd direction, while the contact network of the even and odd directions is electrically separated, and additional neutral inserts are installed in the places of the electrical connection of the contact wires of the even and odd directions. 2. A device according to claim 1, characterized in that additional neutral inserts are installed in the contact network of the even and odd directions of the spans. Sources of information taken into account in the examination 1. Marquardt K. G., Power supply of electric railways. M., “Zheldorizdat, 1963, p. 41-46. . W I & W - / X N .. f f I W About f f%. XG   6 z: I19 ШШ fo Т / г ж1