RU138722U1 - FILTER-COMPENSATING INSTALLATION OF TRACING ELECTRICITY SUPPLY OF AC - Google Patents

Abstract

A filter-compensating traction power supply unit for alternating current, containing two sections, the first being tuned to a resonant frequency of 150 Hz, and the second to 250 Hz, connected in parallel between 27.5 kV buses and a rail, in each of which a switch, a capacitor bank and a reactor are connected in series connected to the rail, and the capacitor bank of the section tuned to 150 Hz is divided into two blocks so that a point with zero potential is formed between them relative to the rail at the main frequency of 50 Hz, and between this a first circuit from a series-connected capacitor and a damping resistor, characterized in that a second circuit from a series-connected capacitor and a damping resistor is connected by a rail and a rail, and the capacitor bank of the second section tuned to a resonant frequency of 250 Hz is also divided into two blocks so that between them there is a point with zero potential relative to the rail at a fundamental frequency of 50 Hz, between which a second circuit from a series-connected capacitor is connected to the rail and damped resistor.

Description

The utility model relates to traction power supply of AC electric railways, in particular, to harmonic filtering and reactive power compensation in traction AC networks (FCU).

The need and circuit solutions for filter-compensating installations in the traction power supply system of railways are considered in [1-6]. Currently, in traction AC networks, two-resonant PKUs are used [4]. Their disadvantage is significant costs due to the fact that the installed capacity exceeds the useful capacity by 2.25 times. More economical PKU containing two sections, tuned to 150 and 250 Hz.

We take the PKU scheme with two sections as a prototype [6, Fig. 2, b], see Appendix. A filter-compensating traction power supply unit for alternating current, containing two sections, the first being tuned to a resonant frequency of 150 Hz, and the second to 250 Hz, connected in parallel between 27.5 kV buses and a rail, in each of which a switch, a capacitor bank and a reactor are connected in series connected to the rail, and the capacitor bank of the section tuned to 150 Hz is divided into two blocks so that a point with zero potential is formed between them relative to the rail at the fundamental frequency of 50 Hz, and between this The first circuit of the series-connected capacitor and damping resistor is connected by a rail and a rail.

As can be seen, in this scheme, to expand the functionality, a damping resistor with a capacitor in the first section tuned to 150 Hz was introduced, forming a broadband filter and allowing additional damping of harmonics above 350 Hz to prevent resonance phenomena in traction networks [1, 6].

However, during the operation of two-sectional control units, undesirable phenomena occur associated with the amplification of current harmonics of 150 Hz between sections tuned to 150 and 250 Hz, and accompanied by the occurrence of increased currents in these sections. This is because for a harmonic of 150 Hz, the first section is the inductive reactance, and the second is the capacitance. An undesirable redistribution of currents in the filter sections is indicated in [3].

So, the disadvantage of the prototype: increased currents in the sections due to the amplification of harmonics, which leads to increased wear of the capacitors.

The purpose of the utility model is to reduce the values of currents flowing in sections due to the additional inclusion of a circuit from a capacitor and a damping resistor in a section of 250 Hz.

To achieve the goal, a second circuit of a series-connected capacitor and a damping resistor was introduced into the transverse capacitive compensation installation, and the capacitor bank of the second section, tuned to a resonant frequency of 250 Hz, is also divided into two blocks so that a point with zero potential relative to the rail is formed between them a fundamental frequency of 50 Hz, between which a rail is connected to a second circuit of a series-connected capacitor and a damping resistor.

The validity of this solution is proved by computational experiments, the results of which are given in table. 1, where the distribution of currents is considered for a two-section PKU circuit with damping circuits.

Table 1. Current distribution between PKU sections f Hz Current ∗, A PKU with a damper in the section of 150 Hz PKU with dampers in both sections I1, A I2, A I1, A I2, A fifty 203 143 60 143 60 150 133 241.9 108.9 158.5 25. 250 80 1,6 78,4 7.2 75.6 350 57 15,5 72.5 12.24 63.9 ∗ - The currents of the higher harmonics of the PKU are taken maximum on the basis of field experiments

As you can see, if the prototype (with a damping resistor and capacitor only in the first section, set to 150 Hz) in the first and second sections currents with a frequency of 150 Hz - 241.9 A and 108.9 A, then in the proposed installation with damping resistors in in both sections, the currents of 150 Hz decreased significantly and are equal to 158.5 A and 25 A. The maximum currents in the sections are reduced at other frequencies.

The filter-compensating installation is shown in the figure, which shows:

1 - bus 27.5 kV.

2 - rails.

3, 4 - the first and second sections of the PKU.

5, 6 - single-phase switches of the first and second sections of the FCU.

7, 8 - capacitor banks of the first and second sections of the PKU.

9, 10 - reactors of the first and second sections of PKU.

11, 12 - capacitors of the first and second sections of the PKU.

13, 14 - damping resistors of the first and second sections of the PKU.

The scheme works as follows. When the first section is turned on, there is no amplification of current harmonics. When connecting the second section with a damping resistor that shunts the inductive reactance of the reactor, as well as in connection with the introduction of active resistance into the second section, the current distribution in the sections is satisfactory (158.5 A and 25 A).

The technical and economic effect is determined by the simplification of the design of KU by reducing the installed capacity of capacitors and reactors due to the reduction of section currents.

Information sources

1. Borodulin B.M., German L.A., Nikolaev G.A. Condenser installations of electrified railways. - M .: Transport, 1983. - 183 s

2. German L.A., Serebryakov A.S. Adjustable capacitive compensation installations in traction power supply systems of railways: monograph / Monograph - M. MIIT, 2012. - 211 p.

3. Ivanov V.S., Sokolov V.I. Consumption regimes and the quality of electric power of industrial enterprise power supply systems. M .: Energoatomizdat, 1987 - 336 s

4. Cheremisin V.T., Kvashchuk V.A., Brenkov S.N. Two-resonance filter-compensating devices of electrified railways, Science and Transport, Modernization of Railway Transport, 2008, p. 48-51.

5. Zhezhelenko I.V. Higher harmonics in power supply systems of industrial enterprises. M .: Energy, 1974.- 184 C

6. Ermolenko D.V. Increasing the electromagnetic compatibility of the traction power supply system with thyristor electric rolling stock. Abstract of dissertation degree of candidate of technical sciences. M .: VNIIZHT, 1991, 22 p.

7. Power equipment of traction substations of railways (collection of reference materials). Russian Railways, a branch of the PKB for Electrification of Railways - M .: Transizdat, 2006.

Claims (1)

A filter-compensating traction power supply unit for alternating current, containing two sections, the first being tuned to a resonant frequency of 150 Hz, and the second to 250 Hz, connected in parallel between 27.5 kV buses and a rail, in each of which a switch, a capacitor bank and a reactor are connected in series connected to the rail, and the capacitor bank of the section tuned to 150 Hz is divided into two blocks so that a point with zero potential is formed between them relative to the rail at the main frequency of 50 Hz, and between this a first circuit from a series-connected capacitor and a damping resistor, characterized in that a second circuit from a series-connected capacitor and a damping resistor is connected by a rail and a rail, and the capacitor bank of the second section tuned to a resonant frequency of 250 Hz is also divided into two blocks so that between them there is a point with zero potential relative to the rail at a fundamental frequency of 50 Hz, between which a second circuit from a series-connected capacitor is connected to the rail and damped resistor.

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