RU138738U1 - FILTER-COMPENSATING INSTALLATION OF AC TRACTION ELECTRICITY SYSTEM - Google Patents

Abstract

Filter-compensating installation of traction power supply system of alternating current with two parallel connected sections connected between the 27.5 kV bus and the rail, the first of them is tuned to a resonant frequency of 150 Hz, and the second is tuned to a frequency of 250 Hz, and a capacitor switch is connected in series in each section a battery and a reactor connected to the rail, characterized in that the second section, tuned to a resonant frequency of 250 Hz, is divided into two blocks so that a point with a zero potential relative to the rail is formed between them a fundamental frequency of 50 Hz and a circuit is introduced from a series-connected capacitor and a damping resistor connected between a point with zero potential of the second section and the rail.

Description

The utility model relates to traction power supply of AC electric railways, in particular to filter compensating installations for reactive power compensation and reduction of voltage harmonics in AC traction networks

Known [1, 2, 3, 4] filter-compensating installations in the traction power supply system of alternating current with two parallel connected first and second sections connected between a 27.5 kV bus and a rail, in each of which a single-phase switch, a capacitor bank and a reactor are connected in series connected to the rail, while 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 point and a rail is connected to the circuit from a series-connected capacitor and a damping resistor.

The disadvantage of such schemes is the relatively large loss of active energy in the damping circuit connected to the section tuned to 150 Hz.

In the proposed utility model, we take as a prototype a scheme of a two-stage filter compensating installation (FCU) [4]: Filter compensating installation of an alternating current traction power supply system with two parallel sections connected between a 27.5 kV bus and a rail, the first of which is tuned to a resonant frequency of 150 Hz and the second - at a frequency of 250 Hz, and in each section a switch, a capacitor bank and a reactor connected to the rail are connected in series.

The purpose of the utility model is to reduce the amount of active power loss in the damping circuit.

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

Comparison of schemes for the proposed utility model and the prototype is performed on a mathematical model and the results are presented in table. . Harmonic currents are taken from existing two-section transverse capacitive compensation systems for traction AC power supply. As you can see, the power loss in the proposed model is much less (19.43 kW) than in the prototype (95.84 kW). In addition, increases the reliability of the damping resistor by reducing its heating.

Table 1. Active power loss in damping circuit f Hz Harmonic current. Prototype Proposed model I, A Damping circuit current Active power loss in damping circuit Damping circuit current Active power loss in the dump circuit I _D , A Pd, kW I _D , A Pd, kW fifty 182 0 0 0 0 150 51 30.5 93.35 1,6 0.27 250 twenty one 00.09 10.9 11.87 350 9 4.9 2.40 8.5 7.29 Losses in the damping circuit, kW 95.84 19.43

The installation of transverse capacitive compensation 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 - capacitor damping circuit.

12 - damping circuit resistor.

In the utility model, we assume that when you turn on the second section of the PKU with a damping circuit, it is necessary to first turn on the first section of the PKU [1].

As calculations show, the frequency characteristics of the PKU at a frequency greater than 450 Hz are the same regardless where the damping circuit is included: in the 150 Hz section or in the 250 Hz section. On the other hand, it is advantageous to include a damping circuit in a 250 Hz section due to lower power losses. The latter is explained by the fact that a lower current value flows through the damping resistor (see Table 1). So, by switching the damping circuit from the section set at 150 Hz (as in the prototype) to the section set at 250 Hz, it was possible to significantly (95.84 / 19.43≈5 times) reduce the power loss in the damping resistor.

The technical and economic effect is determined by a decrease in the amount of active power loss caused by currents flowing in the damping resistor and, therefore, by increasing the reliability of its operation by connecting the damping circuit to the 250 Hz section, and not to the 150 Hz section, as indicated in the prototype.

Information sources

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

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

3. German L.A., Serebryakov A.S. Adjustable lateral capacitive compensation for traction AC networks. Electro, No. 6 - 2009, p. 29-36

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

Claims (1)

Filter-compensating installation of traction power supply system of alternating current with two parallel connected sections connected between the 27.5 kV bus and the rail, the first of them is tuned to a resonant frequency of 150 Hz, and the second is tuned to a frequency of 250 Hz, and a capacitor switch is connected in series in each section a battery and a reactor connected to the rail, characterized in that the second section, tuned to a resonant frequency of 250 Hz, is divided into two blocks so that a point with a zero potential relative to the rail is formed between them a fundamental frequency of 50 Hz and a circuit is introduced from a series-connected capacitor and a damping resistor connected between a point with zero potential of the second section and the rail.

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