RU2524209C2 - Method of electrical energy transfer in direct-current electric-traction network of urban electrified transport through municipal alternating-current network - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention relates to electrical engineering. A method of electrical energy transfer in a DC electric-traction network of urban electrified transport through an AC municipal network is proposed to improve the quality of voltage in both networks simultaneously. Operations of the method comprise integration of DC and AC networks by means of booster transformers connected at the input of municipal transformer substations, and transistor voltage inverters connected to a traction network, with addition of branch line switching operations on the high side at the main transformers of municipal transformer substations by means of mechanical switches. Transformation coefficients of the main transformers of municipal transformer substations are changed by branch line switching; with that, at the beginning of the electric-traction network where voltage is increased an increased transformation coefficient is set, and at the end of the electric-traction network where voltage is decreased a decreased transformation coefficient is set. Transformation coefficients of the rest municipal transformer substations are uniformly changed relative to the nominal value from increased to decreased one as far as they go from the beginning of the electric-traction network to its end.

EFFECT: method allows obtaining the following technical result: redistribution of energy from the beginning of the electric-traction network to its end through municipal networks, thus equalising voltage throughout the length of the electric-traction network with simultaneous voltage stabilisation at the input of municipal substations.

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Description

The invention relates to electrical engineering, in particular to urban power supply systems, and can be used in the combined networks of public utilities and urban electrified transport.

A known method of regulating the voltage on the high side of an urban transformer substation by switching the solder off mechanical switch. This method is applicable only when the substation is off. This method of changing the voltage is called "switching without excitation" (PBB). (see. Sergeenkov B.N. et al. Electric machines: Transformers: Textbook for electrical engineering. special universities. / B.N.Sergeenkov, V.M. Kiselev, N.A. Akimova; Ed. I. P. Kopylova, Moscow: Higher School, 1989, p. 280).

This method is used extremely rarely, maybe every few years, if the capacity of consumers in the microdistrict has changed significantly or the power supply scheme has changed. It is used to equalize voltage among consumers, however, but it is not applicable for voltage stabilization.

Closest to the proposed one is a method of energy redistribution by combining electric networks using inverters and voltage boost transformers (RF Patent for Utility Model No. 108236 of 02.02.2011, H02J 5/00, / V.S. Klimash, Yu.M. Inkov, D.V. Pimenov (Russia)). This method allows you to transfer energy both from the traction network to the utility, and vice versa. The direction of transmission depends on the voltage level at the input of the utility substation and does not depend on the load and the amount of power consumed in the traction network. So, for example, in the process of stabilizing the voltage at the input of communal transformer substations and at consumers, when the voltage is reduced in the communal network, the voltage-boosting device installed on the transformer substation operates in the voltage adding mode, consuming energy from the traction network, and when the voltage is increased, it works in the mode voltage subtraction, giving energy to the traction network (see Klimash BC Booster devices for compensating voltage and reactive energy deviations with amplitude, imp pulse and phase regulation: Monograph. - Vladivostok: Dalnauka, 2002, p. 53).

The disadvantage of this method is that with such a redistribution of energy between networks, the improvement of voltage quality will be only for utility consumers.

The objective of the proposed method is to improve the quality of the voltage in both the communal and traction networks due to the transfer of boosting devices in the areas of low voltage in the traction network to the mode of energy consumption from the communal network, and in the mode of transferring energy to the communal network in areas of high voltage of the traction network . In this case, as you move away from areas with high voltage in the traction network to areas with low voltage in the traction network, the energy consumption from the traction network decreases evenly, followed by a uniform increase in the transfer of energy from the communal network to the traction network.

The problem is solved due to the fact that during the redistribution of electric energy between the utility AC network and the traction network of direct current of urban electrified vehicles, connected via boosting transformers with secondary windings connected through inverters to the traction network and with primary windings included in the primary winding circuit corresponding main transformers of utility transformer substations, which are made with soldering and mechanical switching we use these solders to change the transformation coefficient, and taking into account the voltage drop at the end of the traction network, its value at the beginning connected to the output of the traction substation is set increased, a change in the transformation coefficient of the main transformer of the communal transformer substation located and connected at the beginning of the traction network is introduced the tap switch to a higher value, and the transformation ratio of the main transformer of the utility transformer substation, The power supply is connected to the traction network of the remaining communal transformer substations and is selected taking into account the step of changing the transformation ratio and the number of connected communal transformer substations, and the transformation ratios of these communal transformer substations are reduced relative to the nominal values from high to low as you move from the beginning to the end of the traction network.

As a result of solving this problem, the quality of the supply voltage of both municipal consumers and urban electrified transport will be improved.

The essence of the claimed method is illustrated by the description below and the drawing attached to it, which shows the power supply circuit with boosters and mechanical solder switches, with which this method is implemented.

The following notation is introduced in the drawing: traction substation (1), section of the contact network (2), vehicles (3, 4), utility transformer substations (5, 6, 7), voltage boosters (8, 9, 10) with voltage boost transformer (11), voltage inverter (12), inductive-capacitive filter (13); main transformers of transformer substations (14, 15, 16) with mechanical solder switches, consumers of a public network (17, 18, 19).

The method is as follows. At utility transformer substations located close to the traction substation, using the mechanical solder switch, the maximum transformation coefficient is set at which the voltage in the utility network is reduced and the booster device operates in the voltage addition mode, consuming energy from the traction network, additionally loading it and reducing her stress. At the same time, boosting devices, working in the mode of the voltage stabilizer of consumers, increase the voltage at the input and output of communal transformer substations. At communal transformer substations remote from the traction substation, the transformation ratio of the main transformers is set to the minimum value at which the voltage in the communal network will be increased, and the voltage-boosting device, stabilizing the voltage, will work in the voltage mode, while transferring energy from the communal network to the traction network.

Depending on the length of the line, the transformation coefficients are uniformly changed, and from the beginning to the middle they are reduced relative to the nominal value, and from the middle to the end they are increased.

The proposed method, as more advanced, is intended for use in the integrated power supply system of municipal and traction networks of urban electrified transport without significant capital investments.

Claims (1)

The method of electric energy flows in a direct current traction network of urban electrified vehicles through a utility AC network, connected via booster transformers, with secondary windings connected through voltage inverters to the traction network and with primary windings included in the primary winding circuit of the corresponding main transformers of communal transformer substations which are made with solders and a mechanical switch of these solders, for example, switch b without excitation to change the transformation coefficient, and taking into account the voltage drop at the end of the traction network, its value at the beginning connected to the output of the traction substation is set increased, characterized in that the transformation coefficient of the main transformer of the communal transformer substation located and connected at the beginning of the traction network, is set by the tap switch to an increased value, and the transformation ratio of the main transformer of the communal transformer substation, laid and connected at the end of the traction network, set the tap-off switch to a lower value, while the sections of connection to the traction network of the remaining communal transformer substations are selected taking into account the step of changing the transformation coefficient and the number of connected communal transformer substations, and the transformation ratios of these communal transformer substations are reduced relative to the nominal values from high to low as you move from the beginning to the end of the traction network.