RU2351487C1 - METHOD OF CHANGING 3,3 kV DC ELECTRIFIED TRACT SECTION OVER TO SINGLE-PHASE 25,5 kV AC AND DEVICE TO THIS END - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: invention relates to the methods of changing 3.3kV-DC electrified track sections over to single-phase 27.5 kV AC for all existing electrified track sections. The proposed method consists in that, first, the three-phase alternating current is converted by rectifier-converter hardware into a single-phase AC. For this, no special high-power rectifier-converter substations are erected but the existing DC substation infrastructure is exploited including from primary DC supply voltage lead-ins to 3.3kV-DC buses.

EFFECT: reduced costs of changing over to AC thanks to using existing D C traction substations followed by erection of new ones, ruling out constructing neutral inserts in overhead system, complete symmetry in phase loading of outside electric power supply lines over their entire length, reduced power losses in said lines and at electric power stations.

3 cl, 1 dwg

Description

The invention relates to methods for transferring sections of railways electrified with a direct current of 3.3 kV to alternating current of 25 kV and can be used to transfer all existing sections of railway direct current, and especially the main sections where it is supposed to organize high-speed movement.

There are three well-known alternative ways of transferring railway sections. from direct to alternating current.

At the first of them [1], more powerful, but more rarely located (at a distance of 40-50 km from each other), traction substations of alternating current 25 kV are constructed, and the existing substations of direct current are dismantled.

In the second [2], which is still being developed and proposed for use mainly in newly electrified areas. etc., at a distance of 150-200 km from each other, powerful support traction substations with balancing transformers are built, with a voltage on the secondary side of 94 kV, while a 94 kV longitudinal two-phase line is laid between the support substations, supplying a number of typical standard substations, feeding their own turn contact network 25 kV.

In the third [3] method, which is also just being developed and also recommended for use in newly electrified railway sections, it is proposed to build powerful support substations, but carrying out rectifier-inverter conversion of an alternating three-phase current to a single-phase voltage of 110 kV, laying a two-phase power line 110 kV between reference substations and on console sections from them, from which typical standard substations are fed along the railway lines, which in turn feed a 25 kV contact network.

The latter method is closest to the proposed one, which is why it is taken as a prototype.

The technical result of the use of the device is: reduction of reduced costs for converting sections to alternating current due to the lack of need for dismantling of existing DC traction substations and the subsequent construction of new ones; eliminating the need for the construction of neutral inserts in the contact network; achieving full symmetry of the phase loadings of external power supply lines along their entire length, reducing energy losses in the external power supply system and at power plants; reduction of energy losses in the contact network due to the reduction of the lengths of inter-substation zones compared to the lengths of inter-substation zones in typical sections of alternating current 25 kV.

The conversion of direct current sections to alternating current according to all the above methods requires the complete dismantling of existing DC substations, enormous expenses for the construction of powerful traction AC substations, and in the second and third methods the construction of longitudinal two-phase power lines of 94-110 kV, as well as solutions power problems of non-traction non-rail consumers with three-phase current.

A significant drawback of all these methods of converting sections electrified with direct current to alternating current is the need to switch to alternating current and all suburban sections of railways adjacent to large junction stations, while there is no energy need for this, because . the mode of movement on them is fully ensured from the contact network of 3.3 kV DC.

Switching to alternating current becomes less costly, and the effect is more significant if it is carried out in the following way, which preserves the entire infrastructure and structure of existing traction substations of direct current 3.3 kV, supplemented by blocks of autonomous voltage inverters that increase output single-phase transformers and switchgear - 25 kV. At the same time, it remains possible to supply all non-traction consumers with three-phase alternating current.

The invention is illustrated in the drawing, where, as an example, is a schematic diagram of a device - an intermediate traction substation on the seals and where:

I - maintained existing infrastructure and structure of traction substation

II - addition of the traction substation structure

1 - three-phase power lines 110 (220) kV external supply voltage

2 - open switchgear (switchgear) 110 (220) kV

3 - step-down transformers 110 (220) / 35/10 kV

4 - power supply for non-traction consumers 35 (10) kV

5 - power supply for traction devices and non-traction consumers 10 (35) kV

6 - transformers of converting units

7 - rectifiers of converting units

8 - 3.3 kV bus

9 - reactor smoothing device

10 - filter smoothing device

11 - feeders supplying a 3.3 kV contact network (3.3 kV switching devices are not shown)

12 - 3.3 kV rail feeder

13 - contact network of DC sections 3.3 kV

14 - rails sections DC

15 - blocks of autonomous voltage inverters with filter devices at the output

16 - step-up superconducting single-phase transformers

17 - 25 kV indoor switchgear

18 - rail feeder 25 kV

19 - feeders feeding a contact network of 25 kV (switching devices are not shown)

20 - contact network of sections of alternating current 25 kV

21 - rails sections AC

The essence of the invention lies in the fact that preliminary carry out rectifier-inverter conversion of an alternating three-phase current into alternating single-phase current. For this purpose, they do not build special powerful rectifier-inverter substations, but use the entire existing infrastructure of DC substations, from the inputs of the primary supply voltage to DC buses of 3.3 kV inclusive.

, которое поступает на вводы однофазных повышающих трансформаторов

16, где оно повышается до 27,5 кВ, а затем поступает на вводы ЗРУ 25 кВ 17, от которого в свою очередь через фидеры контактной сети 19 и рельсовый 18 фидер питаются участки тяговой сети однофазного переменного тока 25 кВ; кроме того, к шинам 3,3 кВ подключены фидеры контактной сети 3,3 кВ 11, а к общей точке реактора и фильтра сглаживающего устройства рельсовый фидер 12, питающие участки тяговой сети постоянного тока 3,3 кВ. При этом, как видно из чертежа, сглаживающее устройство исходной тяговой подстанции постоянного тока (реактор и фильтр-устройство) одновременно выполняет роль входного фильтра инверторных блоков.The device operates as follows: from the switchgear - 110 (220) kV 2, the voltage is supplied to the inputs of the step-down transformers 3, where it drops to 10 (35) kV, the received voltage is supplied to the inputs of the switchgear 10 (35) kV 5, from which in turn converter transformers 6 are fed, in which the voltage drops to 3.3 kV and is supplied to the rectifiers of the converter units 7, where it is converted to a constant voltage of 3.3 kV; the resulting rectified voltage through the 3.3 kV bus 8, as well as the parallel connected reactor 9 and the filter 10 of the smoothing device, is fed to the inputs of the autonomous voltage inverters 15, which convert the 3.3 kV DC voltage to an alternating single-phase voltage

that goes to the inputs of single-phase boost transformers

16, where it rises to 27.5 kV, and then enters the inputs of the switchgear 25 kV 17, from which, in turn, through the feeders of the contact network 19 and the rail 18 feeder, sections of the traction network of a single-phase alternating current 25 kV are fed; in addition, 3.3 kV 11 contact network feeders are connected to 3.3 kV buses, and a rail feeder 12 is connected to the common point of the reactor and filter of the smoothing device, which feed sections of the 3.3 kV DC traction network. Moreover, as can be seen from the drawing, the smoothing device of the initial DC traction substation (reactor and filter device) simultaneously acts as an input filter of inverter units.

The device can be performed with the transformation of the three-phase primary voltage of the external supply network in two stages, as shown in the drawing, and in one. Moreover, the circuit of outdoor switchgear 110 (220) kV 2 of the traction substation can be performed on the seals, as in the drawing, transit or reference, depending on the scheme of the existing DC substation.

Information sources

1. Fuchs N.L. Transfer of electric traction of the main section Winter - Slyudyanka from direct current 3.3 kV to alternating 25 kV. Railways of the world, 1997. - No. 2. - S.3-13.

2. A.M. Vasilyansky, R.R. Mamoshin, G. B. Yakimov. Improving the traction power supply system for railways electrified with alternating current 25 kV, 50 Hz / World Railways, 2002. - No. 8 - P.40-45.

3. Burkov A.T., Grishin Ya.S. Symmetric three-phase-single-phase converter of traction power supply system for alternating current / International Transport Review. Trance. Eurasia, February 2001 .-- 7-8 pp.

Claims (3)

1. The method of transferring sections of railways, electrified with a direct current of 3.3 kV, to an alternating current of 25 kV, carried out by inverting direct current into a single-phase alternating current, characterized in that to obtain a traction single-phase voltage of alternating current 25 kV industrial frequency to the busbars 3 , 3 kV of a DC traction substation additionally connect autonomous inverters that convert a DC voltage of 3.3 kV to a single-phase voltage with an amplitude of 3.3 kV, the resulting voltage using an additional set Vai-phase transformer is increased to 25 kV, filtered and fed to the further bus-mounted dispenser 25 kV, so that by driving feeders feed the catenary sections, previously prepared for operation at a voltage of 25 kV AC. 2. A device consisting of a primary power supply system supplying a 110 (220) kV switchgear to which are connected in series: step-down transformers with a secondary voltage of 35 and 10 kV, switchgears of the indicated voltages, supplying non-traction consumers and converting units formed by transformers of converting units and rectifiers, 3.3 kV DC busbars at the output of the converter units, with fi connected to the plus 3.3 kV DC bus contact network, and to the negative bus through a smoothing device formed by a smoothing reactor and a filter device, a rail feeder connected to the rails of the sections of the 3.3 kV DC network is connected, characterized in that to the 3.3 kV rectified busbars additionally connected autonomous inverters, to the output of which are connected single-phase transformers that increase the voltage with

up to 25 kV, the secondary windings of which through filtering devices are connected to the busbars of the 25 kV switchgear, from which 25 kV AC sections are powered through the feeders of the traction network and the rail feeder. 3. The device according to claim 2, characterized in that the single-phase transformers that increase the voltage from the outputs of autonomous inverters with

up to 25 kV, made by superconducting.