RU2552572C1 - 25 kv alternating current supply system for electrified railroads - Google Patents

Abstract

FIELD: electricity.SUBSTANCE: system contains the directional power relays located on traction substations and by their outputs connected to switch control units, and by inputs - with the evaluators of current of power branches of traction substations and voltage transformers of distributing devices 27.5 kV. Each voltage transformer of the contact network feeders of the traction substation is connected by one terminal of primary winding to the contact network feeder of the traction substation, and the secondary winding terminals - to the voltage comparator, these voltage transformers are connected only to one of feeders of the contact network of each power branch of traction substations, the adjacent switch control units of each intersubstation zones are connected to each other by means of communication channels of switch control units, voltage comparators are connected to switch control units, the switch control units are connected by means of communication channels with the control units switches which are also connected through communication channels with the switches of additional parallel connection points, current evaluators of the power branch of the traction substations are connected by the inputs to the current transformers of the contact network feeders of the traction substations, the additional parallel connection points with switches are connected to contact suspension brackets of the neighboring tracks near places of connection of feeders of distributing devices 27.5 kV to contact suspension brackets of the contact network.EFFECT: improved quality of electric power in the power supply system.2 dwg

Description

The claimed invention relates to the field of electrified railways, and can be used to power a traction network of alternating current 25 kV in areas with sharply variable traction loads and high transit currents flowing through the traction network.

To supply single-phase traction loads, double-sided power circuits are used, which, with equal voltage vectors on the buses of 27.5 kV switchgears, ensure the parallel operation of two adjacent traction substations connected to one inter-substation zone to the load of the traction network. Moreover, the distribution of traction load currents between substations is performed with minimal loss of electrical energy in the traction network.

With different voltage vectors on the buses of 27.5 kV switchgears of adjacent traction substations supplying one intersubstation zone, transit currents occur in the traction network, which can lead to large losses of electrical energy in the traction network and power lines, as well as overloading of traction substations.

For electrified railways of alternating current of 25 kV, the problem of choosing power schemes for traction loads with sharply uneven train movement and weak interconnection of high voltage bushings of adjacent traction substations is known.

A known system of electrified railways of alternating current 25 kV [Marquardt, K.G. Power supply of electrified railways [Text]: textbook. for universities railway transp. / K.G. Marquardt - Ed. 4th, rev. and add. - M .: Transport, 1982. - 528 p.].

The 25 kV AC electrified railway system contains power lines, traction substations, a traction network, circuit breaker control devices, and traction loads.

Traction substations contain three-phase three-winding transformers, as well as switchgears.

27.5 kV switchgears contain contact network feeders with circuit breakers and current transformers, as well as voltage transformers.

 The traction network contains a contact network with contact pendants, neutral inserts, insulating mates, a rail network, sectioning posts, as well as parallel connection points.

Each sectioning post is made in the form of a single un-sectioned bus system with circuit breaker feeders. Moreover, the sectioning posts are located in the middle region of the inter-substation zones.

Each parallel connection point contains a switch. Moreover, the points of parallel connection are located in the middle region of the feeder zones between sectioning posts and traction substations.

Switch control devices are located at each traction substation and energy dispatch center.

Traction substations are electrically interconnected by means of power lines and a traction network. Moreover, traction transformers are connected to power lines and traction networks through switchgears of traction substations.

Voltage transformers are connected to the busbars of switchgear 27.5 kV, and current transformers are connected to the feeders of the contact network of traction substations.

The contact network is divided into sections using neutral inserts and insulating mates. Contact pendants of the contact network section are interconnected by means of switches of sectioning posts, parallel connection points and are connected to the busbars of switchgears with a voltage of 27.5 kV of adjacent substations through feeders of the contact network of traction substations.

The rail network is connected to 27.5 kV switchgears.

Switches of feeders of the contact network of traction substations, sectioning posts and points of parallel connection are connected through communication channels to the control devices of these switches.

Traction loads are connected by one output to the contact suspensions of the contact network, and the other to the rail network.

The system of electrified railways AC 25 kV operates as follows.

For each inter-substation zone, the same voltage is applied from two adjacent traction substations. At the same time, traction loads are powered by two substations.

Each electric locomotive in the recovery mode returns energy, which is transmitted through the traction network to trains in the traction mode, located on the inter-substation zone. Excessive energy recovery through three-phase three-winding power transformers is transmitted to the external power supply system.

The switches of the feeders of the contact network of traction substations, sectioning posts and parallel connection points are remotely controlled by supplying the corresponding signals from the substation or energy control center via communication channels.

питающих одну межподстанционную зону потери электрической энергии в схемах с двусторонним питанием тяговых нагрузок минимальны.At equal voltages on the buses of 27.5 kV switchgears of adjacent traction substations i and i + 1 $$\left({\dot{U}}_i={\dot{U}}_{i+\mathrm{one}}\right)$$

supplying one inter-substation zone, losses of electric energy in circuits with two-way power supply of traction loads are minimal.

в тяговой сети будет возникать ток транзита, который приводит к дополнительным потерям электрической энергии (ΔW_Д) в ней.If $${\dot{U}}_i\ne {\dot{U}}_{i+\mathrm{one}}$$

a transit current will occur in the traction network, which leads to additional losses of electric energy (ΔW _D ) in it.

;

;

, $${\dot{U}}_{i+1}$$

- комплексные напряжения на шинах распределительных устройств 27, 5 кВ смежных тяговых подстанций i и i+1, кВ; Z _TC - полное комплексное сопротивление контура тяговой сети, Ом; R_TC - активное сопротивление тяговой сети, Ом; t - расчетный период времени, ч.Where $${\dot{U}}_i$$

, $${\dot{U}}_{i+\mathrm{one}}$$

- complex voltages on the buses of switchgears 27, 5 kV adjacent traction substations i and i + 1, kV; Z _TC - the total complex resistance of the traction network, Ohm; R _TC - active resistance of the traction network, Ohm; t is the estimated time period, h

и двустороннем питании тяговых нагрузок определяются по формулеLoss of electrical energy in the traction network at $${\dot{U}}_i\ne {\dot{U}}_{i+\mathrm{one}}$$

and bilateral power supply of traction loads are determined by the formula

ΔW ₂ = ΔW ₀ + ΔW _d,

.where ΔW ₀ is the loss of electric energy in the two-sided power supply schemes of traction loads at $${\dot{U}}_i={\dot{U}}_{i+\mathrm{one}}$$

.

и тока транзита (при $${\dot{U}}_i\ne {\dot{U}}_{i+1}$$

).Transit in the traction network can overload one of the substations by increasing the load on it, since the substation load will be determined as the sum of the traction loads of the substation (at $${\dot{U}}_i={\dot{U}}_{i+\mathrm{one}}$$

and transit current (at $${\dot{U}}_i\ne {\dot{U}}_{i+\mathrm{one}}$$

)

The advantage of the well-known system of electrified railways of alternating current 25 kV is the minimum loss of electric energy in the traction network with two-way power supply of traction loads at equal voltages on the buses of switchgears of 27.5 kV adjacent traction substations.

The disadvantages of the known system of electrified railways of alternating current 25 kV are.

Large losses of electric energy in the traction network with bilateral supply of traction loads and voltage inequality on the buses of 27.5 kV switchgears of adjacent traction substations, caused by sharply alternating traction load currents and large transit currents flowing through the traction network.

The decrease in the quality of electric energy in the power supply system due to an increase in the asymmetry of currents and voltages in it, which is due to the excess energy of the recovery of the single-phase traction load returned to the three-phase network.

The closest to the claimed technical solution for the combination of essential features is a system of electrified railways of alternating current 25 kV [Figurnov, EP Relay Protection [Text]: Textbook. In 2 hours, part 2. 3rd ed. reslave. and add. / E.P. Figurnov - M. GOU “Educational-methodical center for education in railway transport”, 2009. - 604 p.].

The 25 kV AC electrified railway system contains power lines, traction substations, a traction network, circuit breaker control devices, and traction loads.

Traction substations contain three-phase three-winding transformers and switchgears.

27.5 kV switchgears contain contact network feeders with circuit breakers and current transformers, as well as voltage transformers.

The traction network contains a contact network with contact pendants, neutral inserts, insulating mates, a rail network, sectioning posts, as well as parallel connection points.

Each sectioning station is made in the form of two bus sections with a sectional switch and contact network feeder switches. Moreover, the sectioning posts are located in the middle region of the inter-substation zones.

Each parallel connection point contains a switch. Moreover, the points of parallel connection are located in the middle region of the feeder zones between sectioning posts and traction substations.

Switch control devices are located at each traction substation and energy dispatch center.

Traction substations are electrically interconnected by means of power lines and a traction network. Moreover, traction transformers are connected to power lines and traction networks through switchgears of traction substations.

Voltage transformers are connected to the busbars of switchgear 27.5 kV, and current transformers are connected to the feeders of the contact network of traction substations.

The contact network is divided into sections using neutral inserts and insulating mates. Contact pendants of the contact network section are interconnected by means of sectional switches, switches of feeders of the contact network of sectioning posts, switches of parallel connection points and are connected to the busbars of switchgears with a voltage of 27.5 kV of adjacent substations through feeders of the contact network of traction substations.

Switches of feeders of the contact network of traction substations, sectioning posts and points of parallel connection are connected through communication channels to the control devices of these switches.

The rail network is connected to 27.5 kV switchgears.

Traction loads are connected by one output to the contact suspensions of the contact network, and the other to the rail network.

The system of electrified railways AC 25 kV operates as follows.

Sectional switches for sectioning stations are in the on position. At the same time, the same voltage is applied to each inter-substation zone from two adjacent traction substations. Traction loads are powered by two substations.

The switches of the feeders of the contact network of traction substations, sectioning posts and parallel connection points are also remotely controlled by supplying the corresponding signals from the substation or energy control center via communication channels.

If the voltage inequality on the busbars of the 27.5 kV switchgears of adjacent traction substations in the traction network, transit currents will occur, which lead to additional losses of electrical energy. To eliminate it, they switch from a two-sided power supply circuit to a one-way power supply for traction loads by turning off the sectional switches of the sectioning posts. At the same time, electric locomotives located on each feeder zone receive power from one traction substation.

Each locomotive in recovery mode returns energy that is consumed by traction loads located on one of the substation zones. The transition to a one-way power supply for traction loads reduces the number of electric locomotives that can receive recovery energy. At the same time, the excess energy of the recovery can significantly increase due to a decrease in the number of trains in the substation zone relative to the number of trains in the substation zone. As a result, more excess recovery energy appears to be returned by the single-phase network to the three-phase network of the power system.

The advantage of this system of electrified railways of alternating current of 25 kV is the reduction of electric energy losses in the traction network due to the transit currents in it due to the transition to the scheme of unilateral supply of traction loads by disconnecting the sectional switches of the sectioning posts.

The disadvantages of the known system of electrified railways of alternating current 25 kV are.

Violation of the train schedule due to technological violations in the power supply of traction loads. This is due to the fact that when the sectional switches of the sectioning posts are in the off position and the voltage in the power lines supplying one of the traction substations disappears, the voltage also disappears in the substation zone of this substation. This leads to stopping the movement of trains due to disruption of power supply to traction loads.

Decrease in the efficiency of recovery of electric locomotives due to the transition to a one-way power supply for traction loads, in which, accordingly, the number of trains in traction mode located on a site with trains in a recovery mode is less than in two-way power supply systems for traction loads.

An even greater decrease in the quality of electric energy compared with the analogue system due to a larger increase in the asymmetry of currents and voltages in the power supply system, since an increase in the excess energy of the recovery will deteriorate the quality of electric energy to a greater extent.

The problem solved by the claimed invention is to develop a system of electrified railways of alternating current 25 kV, which ensures uninterrupted power supply to traction consumers, to increase the efficiency of electrified railways with sharply variable traction loads and high transit currents flowing through the traction network "and also to improve the quality electrical energy in the power supply system.

To solve this problem, a system of electrified railways of alternating current 25 kV, containing power lines, traction substations, including three-phase three-winding traction transformers, switchgears with voltage transformers, feeders of a contact network with switches and current transformers, a traction network including a rail network, a contact network with contact pendants, neutral inserts and insulating mates, sectioning posts located in the middle area of the intersystem zones and made in the form of two sections of buses with sectional switches and switches of feeders of the contact network, parallel connection points located in the middle region of the feeder zones of traction substations with switches, control devices located at each traction substation and energy control center, as well as traction loads, traction substations are electrically interconnected by means of power lines and a traction network, traction transformers are connected to power lines and traction networks through switchgear units of traction substations, voltage transformers are connected to busbars of switchgear 27.5 kV, and current transformers are connected to feeders of the contact network of traction substations, the contact network is divided into sections using neutral inserts and insulating mates, contact suspensions of sections of the contact network are connected between by means of sectional switches, switches of feeders of the contact network, sectioning posts, points of parallel connection and are connected to distribution 27.5 kV transmissions via feeders of the contact network of traction substations, and are also connected via communication channels to the control devices of these switches, the rail network is connected to 27.5 kV switchgears, the traction loads are connected to the contact suspensions of the contact network by one output, and to the rail network, is additionally equipped with a power direction relay located on traction substations, voltage transformers of the feeders of the contact network, voltage comparison units, switch control units, circuit breakers the current distribution of the power arms of traction substations, with additional points of parallel connection with switches located near the connection points of the 27.5 kV switchgear feeders to the contact suspensions of the contact network, while the power direction relays are connected to the control units of the switches by their outputs and to the determination units by inputs current of the supply arm of traction substations and voltage transformers of switchgears 27.5 kV, each voltage transformer of switchgears 27.5 In addition, it is connected to the voltage comparison unit by its secondary winding, each voltage transformer of the feeders of the contact network of the traction substation is connected to the feeder of the contact network of the traction substation between the switches and the connection point of the feeder to the contact suspension, and the other terminal of the primary winding to the rail network, and the leads of the secondary winding - to the voltage comparison unit, these voltage transformers are connected to only one of the feeders of the contact network of each traction power supply arm substations, adjacent control units for circuit breakers of each inter-substation zones are connected to each other via communication channels of circuit breaker control devices, voltage comparison units are connected to circuit breaker control units, circuit breaker control units are connected via communication channels to circuit breaker control devices, which are also connected through communication channels to circuit breakers of additional points of parallel connection, the units for determining the current of the power arm of traction substations are connected by their inputs to current transformers of feeders of the contact network of traction substations, additional points of parallel connection with switches are connected to the contact suspensions of adjacent paths near the connection points of the feeders of 27.5 kV switchgear to the contact suspensions of the contact network.

The claimed technical solution differs from the prototype in that it is additionally equipped with power direction switches located on the traction substations, voltage transformers of the contact network feeders, voltage comparison units, circuit breaker control units, power supply arm current detection units on the traction substations, additional parallel connection points with the switches located near the connection points of the 27.5 kV switchgear feeders to the contact suspensions of the contact network. In this case, the power direction relays are connected by their outputs to the control units of the circuit breakers, and by the inputs to the power supply arm detection units of the traction substations and voltage transformers of the 27.5 kV switchgear. Each voltage transformer of 27.5 kV switchgears is also connected to the voltage comparison unit by its secondary winding. Each voltage transformer of the feeders of the contact network of the traction substation is connected to the feeder of the contact network of the traction substation, between the switches and the connection point of the feeder to the contact suspension, the other terminal of the primary winding to the rail network, and the terminals of the secondary winding to the voltage comparison unit. These voltage transformers are connected to only one of the feeders of the contact network of each arm of the power supply of traction substations. Adjacent circuit breaker control units of each inter-substation zones are connected to each other via communication channels of circuit breaker control devices. The voltage comparison units are connected to circuit breaker control units. Circuit-breaker control units are connected via communication channels to circuit-breaker control devices, which are also connected via communication channels to circuit breakers of additional points of parallel connection. The units for determining the current of the arm of the power supply of traction substations are connected by their inputs to the current transformers of the feeders of the contact network of traction substations. Additional points of parallel connection with switches are connected to the contact suspensions of adjacent tracks near the connection points of the 27.5 kV switchgear feeders to the contact suspensions of the contact network.

The presence in the claimed invention of significant distinguishing features indicates the conformity of the claimed technical solution to the patentability criterion of "novelty."

Due to significant distinguishing features, the claimed system of electrified railways of alternating current 25 kV allows to provide uninterrupted power supply to traction consumers, to increase the efficiency of electrified railways with sharply variable traction loads and high transit currents flowing through the traction network, as well as to improve the quality of electric energy in the power supply system . This is due to the fact that, provided the transit current flows towards any traction substation, the power direction relay triggers an advanced signal to the control unit of the substation circuit breakers. Then, the following signals are generated in the control unit of the switches: to prohibit the disconnection of the feeders of the contact network feeders of the adjacent traction substation connected to the same inter-substation zone, to turn on the circuit breaker of an additional parallel connection point located near the connection point of the feeders of the contact network, and to disconnect the switches of the traction contact network substation to which the transit current is directed. As a result of such switching, they switch to the proposed scheme of unilateral power supply of traction loads. Due to this, the traction substation, from which the transit current flowed, is unloaded.

For example, provided that the current of the supply arm of the i-th traction substation in schemes with two-way power supply of traction loads is greater than the current of the supply arm of this substation in the proposed single-sided power supply circuit (i _{i (2)} > i _{i (1)} ), the transition from supply of traction loads to the proposed one-way power scheme.

и $${\dot{U}}_i>{\dot{U}}_{i+1}$$

определятся по следующей формуле:

In schemes with two-way power supply of traction loads, the current of the arm of the power supply of traction substation i at $${\dot{U}}_i\ne {\dot{U}}_{i+\mathrm{one}}$$

and $${\dot{U}}_i>{\dot{U}}_{i+\mathrm{one}}$$

determined by the following formula:

where i _e.k is the current consumed by each k-th electric locomotive; i _tr - current transit.

In the proposed scheme of one-way power supply of traction loads, the current of the supply arm of the traction substation i is determined by the following formula:

In the voltage comparison unit, the voltage values on the tires of the 27.5 kV switchgear (U _w ) are compared with the voltage of the feeders of the contact network (U _fx ) of the traction substation with the disconnected switches of the feeders of the contact network. Under the condition U _fs > U _w , the scheme of one-way power supply of traction loads is preserved.

If when comparing the voltage U _fs > U _w , the voltage comparison unit generates a signal and supplies it to the control unit of the switches. Then, the control unit for the switches sends signals: to turn on the switches of the contact network feeders of this traction substation corresponding to the feeder zone, to turn off the circuit breaker of the additional parallel connection point located near the connection point of the feeders of the contact network of this traction substation, and to allow the disconnection of the switches of the feeders of the contact network of the adjacent traction substation substations connected to one inter-substation zone. As a result of such switching (under the condition i _{i (2)} > i _{i (1)} ), a transition is made from the proposed scheme of unilateral power supply of traction loads to schemes of their bilateral power supply.

The proposed scheme of one-way power supply of traction loads leads to a decrease in the load of traction substations due to the limitation of flowing transit currents through the traction network. It provides uninterrupted power supply to traction consumers in inter-substation zones in case of power failure in power lines supplying the corresponding traction substation. It increases the work of electrified railways with drastically variable traction loads by increasing the number of electric locomotives that can receive recovery energy, and also improves the quality of electric energy in the power supply system by reducing the excess energy of the recovery of single-phase traction loads returned to the three-phase power system.

An unexpected result is that the claimed system of electrified railways of alternating current 25 kV allows us to provide not only uninterrupted power supply to traction consumers, to increase the efficiency of electrified railways with sharply variable traction loads and high transit currents flowing through the traction network, and to improve the quality of electric energy in the power supply system, but also to increase the speed of electric locomotives by the proposed power scheme of traction loads due to ysheniya voltage therein, and in the absence of electric inter- sub station in another zone and eliminate additional rub electrical energy in traction network. This is due to the fact that the transit current in the traction network, along with the currents of electric locomotives, reduces the voltage on their pantographs, and also leads to additional losses of electrical energy. Limiting the transit current will increase the voltage and eliminate additional losses of electric energy in the traction network.

Consider the effect of the applied two-way power supply schemes for traction loads and the operation modes of the electrified railway system on the voltage in the traction network and additional losses of electric energy in it.

In FIG. 1 shows the calculated instantaneous schemes of bilateral and unilateral power supply of traction loads of a single-track section, where

;a) - calculated instantaneous scheme of bilateral power supply of traction loads of a single-track section at $${\dot{U}}_i=U_{i+\mathrm{one}}$$

;

, $${\dot{U}}_i>U_{i+1}$$

и $$i_{тр}^{\text{'}}>i_{0_{i+1}}^{\text{'}}$$

;b) - calculated instantaneous scheme of bilateral power supply of traction loads of a single-track section at $${\dot{U}}_i\ne U_{i+\mathrm{one}}$$

, $${\dot{U}}_i>U_{i+\mathrm{one}}$$

and $$i_{tR}^{\text{'}\text{'}}>i_{0_{i+\mathrm{one}}}^{\text{'}\text{'}}$$

;

c) - design scheme for one-way power supply of traction loads.

, уровень напряжения в тяговой сети выше, чем в схеме одностороннего питания тяговых нагрузок и, соответственно, потери электрической энергии минимальны. При этом токи плеч питания тяговых подстанций i и i+1 определяются по следующим формулам:In the scheme of two-way power traction loads (figa) when $${\dot{U}}_i=U_{i+\mathrm{one}}$$

, the voltage level in the traction network is higher than in the scheme of unilateral power supply of traction loads and, accordingly, the loss of electric energy is minimal. In this case, the currents of the supply arms of the traction substations i and i + 1 are determined by the following formulas:

;

;

;

;

;

;

и $$i_{0_i}^{"}$$

, $$i_{0_{i+1}}^{\text{'}}$$

и $$i_{0_{i+1}}^{"}$$

- соответственно действительные и мнимые составляющие токов плеч питания тяговых подстанций i и i+1.Where $$i_{0_i}^{\text{'}\text{'}}$$

and $$i_{0_i}^{"}$$

, $$i_{0_{i+\mathrm{one}}}^{\text{'}\text{'}}$$

and $$i_{0_{i+\mathrm{one}}}^{"}$$

- respectively, the real and imaginary components of the currents of the supply arms of the traction substations i and i + 1.

The real and imaginary component of the currents of the supply arms of the traction substations i and i + 1 can be found by the following formulas:

;

;

;

;

;

;

;

;

where i _e.k is the current consumed by each k-th electric locomotive; l _k is the distance from the traction substation to the k-th electric locomotives; L is the length of the inter-substation zone.

(например, $${\dot{U}}_i>U_{i+1}$$

) возникает ток транзита (i_тр), который прямо пропорционален разности напряжений на шинах распределительных устройств 27,5 кВ смежных тяговых подстанций i и i+1 и обратно пропорционален полному сопротивлению тяговой сети.Provided $${\dot{U}}_i\ne U_{i+\mathrm{one}}$$

(eg, $${\dot{U}}_i>U_{i+\mathrm{one}}$$

) a transit current (i _tr ) occurs, which is directly proportional to the voltage difference on the buses of the 27.5 kV switchgear of adjacent traction substations i and i + 1 and inversely proportional to the impedance of the traction network.

The transit current is determined by the following formula:

;

;

where φ _Tr is the angle between the transit current and voltage in the traction network.

и $${\dot{U}}_{i+1}$$

значительна, то действительная составляющая тока транзита $$i_{тр}^{\text{'}}$$

может быть больше действительной составляющей тока плеча питания тяговой подстанции $$i_{0_{i+1}}^{\text{'}}$$

(при равных векторах напряжения на шинах тяговых подстанций i и i+1 (фиг.1а)).If the difference of voltage vectors $${\dot{U}}_i$$

and $${\dot{U}}_{i+\mathrm{one}}$$

significant, the real component of the transit current $$i_{tR}^{\text{'}\text{'}}$$

may be greater than the actual current component of the power arm of the traction substation $$i_{0_{i+\mathrm{one}}}^{\text{'}\text{'}}$$

(with equal voltage vectors on the tires of traction substations i and i + 1 (figa)).

и $$i_{тр}^{\text{'}}>i_{0_{i+1}}^{\text{'}}$$

уровень напряжения на пантографах электровозов будут ниже, а потери электрической энергии в тяговой сети выше, чем в схеме с односторонним питанием тяговых нагрузок за счет протекания значительного тока транзита. При этом токи плеч питания тяговых подстанций i и i+1 и токи, протекающие по участкам тяговой сети, определяются по следующим формулам:In the scheme of bilateral power supply of traction loads (figb) under conditions $${\dot{U}}_i\ne U_{i+\mathrm{one}}$$

and $$i_{tR}^{\text{'}\text{'}}>i_{0_{i+\mathrm{one}}}^{\text{'}\text{'}}$$

the voltage level on the pantographs of electric locomotives will be lower, and the loss of electric energy in the traction network is higher than in the scheme with one-way power supply of traction loads due to the flow of a significant transit current. In this case, the currents of the supply arms of the traction substations i and i + 1 and the currents flowing through the sections of the traction network are determined by the following formulas:

;

;

;

;

;

;

;

;

;

;

Therefore, the transition to the proposed scheme of unilateral power supply of traction loads (pigv) will increase the voltage on the pantographs of electric locomotives. In this case, the currents of the supply arms of the traction substations i and i + 1 and the currents flowing through the sections of the traction network are determined by the following formulas:

;

;

;

;

;

;

;

;

;

;

As can be seen from the considered example, in the circuit with two-way power supply of traction loads (fig.1b), the flowing currents in sections of the traction network will be higher than the currents in sections of the traction network flowing in the proposed scheme of unilateral supply of traction loads (figv), and, therefore, the voltage loss, respectively, in the proposed scheme will be lower due to the limitation of the flow of transit current in the traction network.

к предлагаемой схеме питания тяговых нагрузок за счет перехода происходит увеличение напряжения на пантографах электровозов.Therefore, to increase the voltage in the traction network, it is necessary to go by the condition $$i_{tR}^{\text{'}\text{'}}>i_{0_{i+\mathrm{one}}}^{\text{'}\text{'}}$$

to the proposed power supply of traction loads due to the transition, an increase in voltage on the pantographs of electric locomotives occurs.

In the absence of electric locomotives in the inter-substation zones and the flow of transit currents in the traction network, the transition to the proposed power scheme will eliminate additional losses of electrical energy.

Such a causal relationship is not known from the prior art. Therefore, it is new, and the claimed solution meets the criterion of patentability of the invention "inventive step".

In FIG. 2 presents the inventive system of electrified railways of alternating current 25 kV.

The system of electrified railways of alternating current 25 kV contains power lines 1, traction substations 2, traction network 3, control devices for circuit breakers 4, as well as traction loads 5.

Traction substations 2 contain three-phase three-winding transformers 6 and switchgears 7.

27.5 kV switchgear 7 contains feeders of a contact network 8 with switches, current and voltage transformers, voltage transformers 9, power direction switches 10, voltage comparison units 11, switch control units 12, as well as power detection units for traction substation arms 13.

The traction network 3 comprises a contact network 14 with contact suspensions 15, neutral inserts 16, insulating mates 17, a rail network 18, sectioning posts 19, parallel connection points 20, and also additional parallel connection points 21.

Each sectioning station 19 is made in the form of two bus sections with a sectional switch and contact network feeder switches. Moreover, the sectioning posts 19 are located in the middle region of the inter-substation zones.

Each parallel connection point 20 includes a switch. Moreover, the parallel connection points 20 are located in the middle region of the feeder zones of the traction substations 2, and the additional parallel connection points 21 are located near the connection points of the 27.5 kV 7 switchgear feeders to the contact network 14.

Switch control devices 4 are located on each traction substation 2 and energy dispatch point 22.

Traction substations 2 are electrically interconnected by means of power lines 1 and traction network 5. Moreover, traction transformers 6 are connected to power lines 1 and traction network 5 through switchgears 7 of traction substations 2.

Voltage transformers 9 are connected to the buses of switchgears 27.5 kV 7, and current transformers are connected to the feeders of the contact network of traction substations 8.

The contact network 14 is divided into sections using neutral inserts 16 and insulating mates 17. The contact pendants 15 of the contact network section 14 are interconnected by means of sectional switches, switches of the feeders of the contact network of sectioning posts 19, switches of the parallel connection points 20, additional parallel connection points 21 and connected to the busbars of switchgears with a voltage of 27.5 kV 7 adjacent substations 2 through feeders of the contact network of traction substations 8.

The switches of the feeders of the contact network 8 of traction substations 2, sectioning posts 19, parallel connection points 19 and additional parallel connection points are connected 20 through communication channels 23 to the control devices of these switches 4.

The rail network 18 is connected to a switchgear 27.5 kV 7.

Traction loads 5 are connected by one output to the contact suspensions 15 of the contact network 14, and the other to the rail network 18.

The power direction switch 10 is connected by its outputs to the control units of the circuit breakers 12, and the inputs to the power supply current detection units of the traction substations 13 and voltage transformers 9 of the 27.5 kV switchgear. Each voltage transformer 9 of the 27.5 kV switchgear is also connected by its secondary winding to the voltage comparison unit 11. Each voltage transformer of the feeders of the contact network of the traction substation 8 is connected to the feeder of the contact network of the traction substation 8 by one terminal of the primary winding, between the switches and the connection point of the feeder to contact suspension 15, the other terminal of the primary winding to the rail network 18, and the leads of the secondary winding to the voltage comparison unit 11. These voltage transformers are connected t only with one of the feeders of the contact network of each traction substation power supply 8. Adjacent circuit breaker control units 12 of each inter-substation zone are connected to each other via communication channels 23 circuit breaker control devices 4. Voltage comparison blocks 11 are connected to circuit breaker control units 12. Circuit breaker control units 12 connected through communication channels 23 to control devices of switches 4, which are also connected through communication channels 23 with switches of additional points of parallel connection 21. 21. Blocks for determining the current of the arm of the power supply of traction substations 13 are connected by their inputs to the current transformers of the feeders of the contact network of traction substations 8. Additional points of parallel connection 21 with the switches are connected to the contact suspensions 15 of adjacent tracks near the connection points of the feeders of switchgear 27.5 kV 8 to contact pendants 15 contact network 15.

The inventive system of electrified railways of alternating current 25 kV operates as follows.

The switches of the feeders of the contact network of traction substations 8, sectioning posts 19, parallel connection points 20 and additional parallel connection points 21 are also remotely controlled by supplying the corresponding signals from substation 2 or energy dispatch point 22 via communication channels 23.

Sectional switches of the sectioning posts 19 are in the on position, the switches of the parallel connection points 20 are turned on, and the switches of the additional parallel connection points 21 are turned off. At the same time, the same voltage is applied to each inter-substation zone from two adjacent traction substations 2. Traction loads 5 receive power from two substations 2.

Under the condition that the transit current flows towards any traction substation 2, the power direction relay 10 activates an advanced signal to the control unit of the circuit breakers 12 of the substations 2. Then, the signals are generated in the control unit of the circuit breakers 12: to prohibit the disconnection of the feeders of the contact network of the adjacent traction substation 8 connected to one inter-substation zone, to turn on the switches of the additional point of parallel connection 21, located near the connection point of the feeders of the contact network 8, and to turn off switching feeders of the contact network of the traction substation 8, to which the transit current is directed. As a result of such switching, they switch to the proposed scheme of unilateral power supply of traction loads 5. Due to this, traction substation 2, from which the transit current flowed, is unloaded.

For example, under the condition i _{i (2)} > i _{i (1)} , a transition is made from the two-sided power supply schemes for traction loads 5 to the proposed one-way power supply scheme.

In the voltage comparison unit 11, the values of U _{w are} compared with the values of U _fs and, provided U _fs > U _w , the scheme of one-way power supply of traction loads 5 is saved.

If when comparing the voltage U _fks > U _w , the voltage comparison unit 11 generates a signal and sends it to the control unit of the switches 12. Then the control unit of the switches 12 sends signals: to turn on the feeder switches of the contact network of this traction substation 8, corresponding to the feeder zone, to turn off the circuit breaker of an additional point of parallel connection 21 located near the connection point of the feeders of the contact network of this traction substation, and to enable the disconnection of the circuit breakers of the contact network feeders with inter traction substation 8 connected to one inter-substation zone. As a result of these switches, the transition from the proposed scheme of unilateral power supply of traction loads 5 to the schemes of their bilateral power supply.

Thus, the use of the inventive system of electrified railways of alternating current 25 kV in comparison with the prototype system allows for uninterrupted power supply to traction consumers, to increase the efficiency of electrified railways with sharply variable traction loads and high transit currents flowing through the traction network, as well as to increase quality of electrical energy in the power supply system.

In addition, the inventive system of electrified railways of alternating current 25 kV allows you to further increase the speed of trains in the proposed scheme with one-way power supply of traction loads compared to the two-way power scheme, provided that the voltage inequality on the buses of adjacent switchgears 27.5 kV traction substations supplying one inter-substation zone, and in addition, in the absence of electric locomotives in the inter-substation zone, it eliminates additional losses of electric energy in the traction network tee.

Claims (1)

The 25 kV AC electrified railway system contains power lines, traction substations, including three-phase three-winding traction transformers, switchgears with voltage transformers, contact network feeders with circuit breakers and current transformers, a traction network including a rail network, a contact network with contact suspensions, neutral inserts and insulating interfaces, sectioning posts located in the middle region of the inter-substation zones and made in e two bus sections with section switches and contact network feeder switches, parallel connection points located in the middle area of the feeder zones of the traction substations with switches, control devices located on each traction substation and energy control center, as well as traction loads, while the traction substations are electrically interconnected by power lines and traction network, traction transformers connected to power lines and traction network through distribution devices three traction substations, voltage transformers are connected to the busbars of switchgear 27.5 kV, and current transformers are connected to feeders of the traction substation contact network, the contact network is divided into sections using neutral inserts and insulating mates, the contact suspensions of the sections of the contact network are interconnected by sectional circuit breakers, circuit breakers for contact network feeders, sectioning posts, parallel connection points and are connected to 27.5 kV switchgears via con feeders active network of traction substations, as well as connected through communication channels to the control devices of these switches, the rail network is connected to 27.5 kV switchgear, traction loads are connected to the contact suspensions of the contact network by one output, and to the rail network by the other, characterized in that the system is additionally equipped with power direction switches located at traction substations, voltage transformers of contact feeders, voltage comparison units, circuit breaker control units, detection units the current of the supply arms of traction substations, with additional points of parallel connection with switches located near the connection points of the 27.5 kV switchgear feeders to the contact suspensions of the contact network, while the power direction relays are connected to the control units of the switches by their outputs and to the determination units by inputs current of the supply arm of traction substations and voltage transformers of switchgears 27.5 kV, each voltage transformer of switchgears 27.5 kV so with its secondary winding it is connected to the voltage comparison unit, each voltage transformer of the feeders of the contact network of the traction substation is connected to the feeder of the contact network of the traction substation between the switches and the connection point of the feeder to the contact suspension, the other terminal of the primary winding to the rail network, and the leads of the secondary winding - to the voltage comparison unit, these voltage transformers are connected to only one of the feeders of the contact network of each power supply arm of the traction substation th, adjacent control units for circuit breakers of each inter-substation zones are connected to each other via communication channels of circuit breaker control devices, voltage comparison units are connected to circuit breaker control units, circuit breaker control units are connected via communication channels to circuit breaker control devices, which are also connected through communication channels to circuit breakers of additional points of parallel connection, the units for determining the current of the arm of the power supply of traction substations are connected by their inputs to trans Matora current feeders catenary traction substations, additional items connected in parallel with the switches connected to the overhead catenary adjacent paths vicinity of feeders connecting switchgear 27.5 kV to catenary catenary.

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