CN114407734B - Flexible traction power supply system and protection method - Google Patents

Abstract

The invention discloses a flexible traction power supply system and a protection method, the system comprises a first flexible traction transformer, a first existing traction transformer, a second flexible traction transformer and a second existing traction transformer, wherein the first existing traction transformer, the first flexible traction transformer, the second flexible traction transformer and the second existing traction transformer are sequentially arranged and connected to a bus through corresponding circuit breakers, the system further comprises circuit breakers QF4, a circuit breaker QF5, a circuit breaker QF5' and a circuit breaker QF4 ', the circuit breakers QF4 and the circuit breaker 5 are respectively positioned on two sides of an electrical phase splitting a, the circuit breaker QF5 and the circuit breaker QF5' are respectively positioned on two sides of an electrical phase splitting b, and the circuit breakers QF5' and the QF4 ' are respectively positioned on two sides of an electrical phase splitting c to realize through power supply of power supply arms on two sides of the electrical phase splitting c, thereby solving the problems of reactive power, reactive power and reactive power existing in the existing traction power supply system, Negative sequence and harmonic power quality problems, and improved power supply capability.

Description

A flexible traction power supply system and protection method

technical field

The invention belongs to the technical field of traction power supply, and in particular relates to a flexible traction power supply system and a protection method.

Background technique

At present, the traction power supply system for electrified railways in the world basically adopts the three-phase-two-phase power supply mode. The substation takes the power from the three-phase power grid through the traction transformer and then divides it into two power supply arms to output power, so as to supply power to the traction network. , because the voltage phase, amplitude and frequency of the power supply arms are difficult to be completely consistent, electrical phase separation needs to be set between each power supply arm, but this traction power supply system has the problems of low power quality and poor power supply capability.

Therefore, how to reduce or even cancel the electrical phase separation device in the traditional railway traction power supply system and solve the problems of low power quality and poor power supply capacity, and how to improve the power supply reliability of the flexible traction power supply system and provide suitable The comprehensive protection method is a technical problem to be solved by those skilled in the art.

SUMMARY OF THE INVENTION

The purpose of the present invention is to reduce or even cancel the electrical phase separation device in the traditional railway traction power supply system, and improve the power quality and power supply capability, and propose a flexible traction power supply system and a protection method.

The technical scheme of the present invention is: a flexible traction power supply system, characterized in that the system includes:

A first flexible traction transformer, which includes a circuit breaker QF6, a first energy-saving traction transformer, a circuit breaker QF8, a first matching transformer, a first three-phase-single-phase converter, and a circuit breaker connected in sequence QF10, wherein the primary three-phase of the first energy-saving traction transformer is connected to the three-phase power grid through the circuit breaker QF6, and the secondary three-phase of the first energy-saving traction transformer is matched with the first energy-saving traction transformer through the circuit breaker QF8 The primary side of the transformer is three-phase connected, the secondary side of the first matching transformer is connected to the input end of the first three-phase-single-phase converter, and the output end of the first three-phase-single-phase converter Connect to bus A through the circuit breaker QF10;

The first existing traction transformer, the input end of the first existing traction transformer is connected to the three-phase power grid through the circuit breaker QF1, the first output end of the first existing traction transformer is connected to the bus A through the circuit breaker QF2, The second output end of the first existing traction transformer is connected to the busbar B through the circuit breaker QF3;

The second flexible traction transformer includes a circuit breaker QF6', a second energy-saving traction transformer, a circuit breaker QF8', a second matching transformer, a second three-phase-single-phase converter and Circuit breaker QF10', wherein the primary three-phase of the second energy-saving traction transformer is connected to the three-phase power grid through the circuit breaker QF6', and the secondary three-phase of the second energy-saving traction transformer is connected to the three-phase grid through the circuit breaker QF8 ' is connected with the primary three-phase of the second matching transformer, the secondary side of the second matching transformer is connected with the input end of the second three-phase-single-phase converter, and the second three-phase-single-phase transformer The output end of the current transformer is connected to the busbar A' through the circuit breaker QF10';

The second existing traction transformer, the input end of the second existing traction transformer is connected to the three-phase grid through the circuit breaker QF1', and the first output end of the second existing traction transformer is connected to the bus A through the circuit breaker QF2' ' connection, the second output end of the second existing traction transformer is connected to the busbar B' through the circuit breaker QF3';

Wherein, the first existing traction transformer, the first flexible traction transformer, the second flexible traction transformer, and the second existing traction transformer are arranged and connected to the busbar in sequence;

The system also includes a circuit breaker QF4, a circuit breaker QF5, a circuit breaker QF5', and a circuit breaker QF4'. The circuit breakers QF5' are located on both sides of the electrical split-phase b respectively, and the circuit breakers QF5' and QF4' are respectively located on both sides of the electrical split-phase c, wherein the electrical split-phase a and the electrical split-phase c are respectively flexible traction transformers. Substation 1 and flexible traction substation 2 are divided into electrical phases, the electrical phase b is the electrical phase separation between the flexible traction substation 1 and the flexible traction substation 2, and the electrical phase a is connected in parallel with a circuit breaker QF11, parallel circuit breaker QF12 at the electrical split phase b.

Further, the first energy-saving traction transformer is also connected to bus A and bus B through circuit breaker QF7, and the second energy-saving traction transformer is also connected to bus A' and bus B' through QF7'.

The present invention also provides a protection method for a flexible traction power supply system, which is applied to the above-mentioned flexible traction power supply system, and the method includes the following steps:

S1. Real-time monitoring of system circulation, electrical quantities at various places in the system, working state of each circuit breaker and protection action signal, the working state includes tripping and closing, and the electrical quantities at various places in the system include the voltage and current at each circuit breaker, The protection action signal includes protection action and protection inaction;

S2. Determine the faulty equipment based on the circulating current of the system, the electrical quantities in all parts of the system, the working state of each circuit breaker and the protection action signal;

S3. Control each circuit breaker according to the faulty device.

Further, in the step S2, the faulty equipment is determined based on the circulating current of the system, the electrical quantities of various parts of the system, the working state of each circuit breaker and the protection action signal, which specifically includes:

If the system circulating current is greater than the preset maximum limit, the system fails to be connected to the grid;

If the system has a protective action, the circuit breaker QF10 and the circuit breaker QF8, or the circuit breaker QF6 and the circuit breaker QF8 are tripped, and the circuit breaker QF10', QF6', circuit breaker QF5', circuit breaker QF5 and circuit breaker QF8' are all closed , the first flexible traction transformer is faulty;

If the system has a protective action, the circuit breaker QF10' and the circuit breaker QF8', or the circuit breaker QF6' and the circuit breaker QF8' are tripped, and the circuit breaker QF5', the circuit breaker QF5, the circuit breaker QF6, the circuit breaker QF8 and the circuit breaker QF8' are tripped. When the circuit breakers QF10 are all closed, the second flexible traction transformer is faulty;

If the system has a protection action, the circuit breaker QF10 and the circuit breaker QF5 are tripped, and the circuit breaker QF5', the circuit breaker QF10', the circuit breaker QF6', the circuit breaker QF8', the circuit breaker QF8 and the circuit breaker QF6 are all tripped. When closed, the busbar fault at the first flexible traction transformer;

If the system has a protection action, the circuit breaker QF10' and the circuit breaker QF5' are tripped, and the circuit breaker QF5, the circuit breaker QF10, the circuit breaker QF6, the circuit breaker QF8, the circuit breaker QF8' and the circuit breaker QF6' are all tripped. When closed, the busbar fault at the second flexible traction transformer;

If the system has a protection action, when the circuit breaker QF10, the circuit breaker QF8, the circuit breaker QF10' and the circuit breaker QF8' are tripped and the circuit breaker QF5 and the circuit breaker QF5' are closed, or, the system has a protection action, the circuit is opened When circuit breaker QF6', circuit breaker QF8', circuit breaker QF6 and circuit breaker QF8 are tripped and circuit breaker QF5 and circuit breaker QF5' are closed, or, the system has a protection action, circuit breaker QF6', circuit breaker QF8', circuit breaker QF8', circuit breaker QF5' is closed When QF8 and circuit breaker QF10 are tripped and circuit breaker QF5 and circuit breaker QF5' are closed, or, the system has a protective action, circuit breaker QF8', circuit breaker QF10', circuit breaker QF6 and circuit breaker QF8 are tripped and circuit breakers QF5 and When the circuit breaker QF5' is closed, both the first flexible traction transformer and the second flexible traction transformer are faulty;

If the system has a protection action, the circuit breaker QF10 and the circuit breaker QF5 are tripped and the circuit breaker QF5', the circuit breaker QF6 and the circuit breaker QF8 are closed, and at the same time, the circuit breaker QF10' and the circuit breaker QF8' are tripped, or, the When the system has a protection action, when the circuit breaker QF6' and the circuit breaker QF8' are tripped, the bus at the first flexible traction transformer is faulty and the second flexible traction transformer is faulty;

If the system has a protection action, the circuit breaker QF10' and the circuit breaker QF5' are tripped and the circuit breaker QF5, the circuit breaker QF6', and the circuit breaker QF8' are closed, and at the same time, the circuit breaker QF10 and the circuit breaker QF8 are tripped, or the circuit breaker QF10 and the circuit breaker QF8 are tripped. When QF6 and circuit breaker QF8 trip, the first flexible traction transformer is faulty and the bus at the second flexible traction transformer is faulty;

If the system has a protection action, when the circuit breaker QF10, circuit breaker QF5, circuit breaker QF5' and circuit breaker QF10' are all tripped and circuit breaker QF6, circuit breaker QF6', circuit breaker QF8, and circuit breaker QF8' are closed, Then the busbar at the first flexible traction transformer is faulty and the busbar at the second flexible traction transformer is faulty;

If the electrical quantity at the circuit breaker QF5 or circuit breaker QF5' reaches the set protection action value and meets the fault direction condition, the circuit breaker QF10, circuit breaker QF10', circuit breaker QF6, circuit breaker QF6', circuit breaker QF8 and When the circuit breakers QF8' are all closed and no protection action signal is sent, it is a catenary fault.

Further, the step S3 is as follows:

If the fault is the failure of the system to be connected to the grid, the circuit breaker QF12 will be disconnected, so that the first flexible traction transformer can supply power between the electrical split-phase a and electrical split-phase b and the power supply arm on the left side of electrical split-phase a, so that the second flexible traction transformer can supply power The flexible traction transformer supplies power to the power supply arm on the right side of the electrical split phase b;

If the fault is the fault of the first flexible traction transformer, closing the circuit breaker QF1 and the circuit breaker QF2;

If the fault is the fault of the second flexible traction transformer, closing the circuit breaker QF2';

If the fault is a busbar fault at the first flexible traction transformer, controlling the second flexible traction transformer to supply power to the power supply section of the system;

If the fault is a busbar fault at the second flexible traction transformer, controlling the first flexible traction transformer to supply power to the power supply section of the system;

If the fault is that both the first flexible traction transformer and the second flexible traction transformer are faulty, the circuit breaker QF11 and the circuit breaker QF12 are both disconnected, so that the system returns to the existing traction power supply state;

If the fault is the fault of the busbar at the first flexible traction transformer and the fault of the second flexible traction transformer, the circuit breaker QF2' is closed, so that the second existing traction transformer supplies power to the through power supply section;

If the fault is the fault of the first flexible traction transformer and the fault of the bus at the second flexible traction transformer, the circuit breaker QF1, the circuit breaker QF2, the circuit breaker QF3 and the circuit breaker QF4 are closed, and the circuit breaker QF11 is opened, so that the first 1. The existing traction transformer supplies power to the traction network;

If the fault is a bus failure at the first flexible traction transformer and a bus failure at the second flexible traction transformer, stopping the system;

If the fault is a catenary fault, control the corresponding circuit breaker to close or open according to the position of the catenary fault.

Further, if the fault is a catenary fault, control the corresponding circuit breaker to close or open according to the catenary fault position, as follows:

Determine the fault location;

If the catenary fault is located on the left side of the electrical split phase a, disconnect the circuit breaker QF11;

If the catenary fault is located between the electrical sub-phase a and the electrical sub-phase b, the circuit breaker QF11, the circuit breaker QF12 and the circuit breaker QF5 are opened, and the circuit breaker QF1, the circuit breaker QF3 and the circuit breaker QF4 are closed, so as to The left side of the electrical split phase a is powered by the first existing traction transformer, and the second flexible traction transformer is powered between the electrical split phase b and the electrical split phase c;

If the catenary fault is located between the electrical split phase b and the electrical split phase c, the circuit breaker QF12 and the circuit breaker QF5' are disconnected, so that the power supply arm on the left side of the electrical split phase b is powered by the first flexible traction transformer .

Compared with the prior art, the present invention has the following beneficial effects:

(1) A flexible traction power supply system proposed by the present invention includes a first flexible traction transformer, a first existing traction transformer, a second flexible traction transformer and a second existing traction transformer, wherein the first existing traction transformer The transformer, the first flexible traction transformer, the second flexible traction transformer, and the second existing traction transformer are arranged in sequence and connected to the busbar through corresponding circuit breakers. The system further includes circuit breakers QF4, circuit breakers QF5, circuit breakers QF5', circuit breaker QF4', circuit breaker QF11 and circuit breaker QF12, the circuit breaker QF4 and circuit breaker QF5 are respectively located on both sides of the electrical split phase a, and the circuit breaker QF5 and the circuit breaker QF5' are respectively located on the electrical split phase On both sides of b, the circuit breakers QF5' and QF4' are respectively located on the two sides of the electrical split phase c, and the circuit breakers QF11 and QF12 are connected in parallel at both ends of the electrical split phase a and the electrical split phase b respectively, which can be eliminated. Connect the electrical phase between the stations in the power supply section, realize the power supply arm on both sides of the electrical phase separation, solve the power quality problems such as reactive power, negative sequence and harmonics existing in the existing traction power supply system, and improve the power supply capacity .

(2) The protection method of the flexible traction power supply system proposed by the present invention can realize the self-healing and reconstruction of the flexible traction power supply system in the case of various faults of a single or multiple flexible traction substations, and ensure that the system can be operated in a variety of ways. The stable power supply after fault isolation and removal in the fault state improves the power supply reliability of the flexible traction power supply system, and avoids the failure rate of the power electronic devices in the flexible traction power supply system. technical problem.

Description of drawings

FIG. 1 is a schematic structural diagram of a flexible traction power supply system provided by an embodiment of the present invention;

FIG. 2 is a schematic flowchart of a protection method for a flexible traction power supply system provided by an embodiment of the present invention;

FIG. 3 is a schematic diagram showing a normal operation state of a flexible traction power supply system in an embodiment of the present invention;

FIG. 4 is a schematic diagram showing the operation state of the first flexible traction transformer fault in the embodiment of the present invention;

FIG. 5 is a schematic diagram showing the operation state of the first flexible traction transformer when the busbar is faulty as an example in the embodiment of the present invention;

FIG. 6 is a schematic diagram showing the operating state when both the first flexible traction transformer and the second flexible traction transformer are faulty in the embodiment of the present invention;

FIG. 7 is a schematic diagram showing the operation of the system when the bus at the first flexible traction transformer is faulty and the second flexible traction transformer is faulty in the embodiment of the present invention;

FIG. 8 is a schematic diagram of system operation when the first flexible traction transformer is faulty and the bus at the second flexible traction transformer is faulty according to the embodiment of the present invention;

9 is a schematic diagram of a system when the busbar at the first flexible traction transformer is faulty and the busbar at the second flexible traction transformer is faulty in an embodiment of the present invention;

FIG. 10 is a schematic diagram of the system operation state when the catenary ab segment of the flexible traction power supply system is faulty as an example in the embodiment of the present invention;

FIG. 11 is a schematic diagram showing the disconnected operation state of the flexible traction power supply system in the embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

The application proposes a flexible traction power supply system, as shown in FIG. 1 , a schematic structural diagram of a flexible traction power supply system proposed in an embodiment of the application, including:

A first flexible traction transformer, which includes a circuit breaker QF6, a first energy-saving traction transformer, a circuit breaker QF8, a first matching transformer, a first three-phase-single-phase converter, and a circuit breaker connected in sequence QF10, wherein the primary three-phase of the first energy-saving traction transformer is connected to the three-phase power grid through the circuit breaker QF6, and the secondary three-phase of the first energy-saving traction transformer is matched with the first energy-saving traction transformer through the circuit breaker QF8 The primary side of the transformer is three-phase connected, the secondary side of the first matching transformer is connected to the input end of the first three-phase-single-phase converter, and the output end of the first three-phase-single-phase converter Connect to bus A through the circuit breaker QF10;

The first existing traction transformer, the input end of the first existing traction transformer is connected to the three-phase power grid through the circuit breaker QF1, the first output end of the first existing traction transformer is connected to the bus A through the circuit breaker QF2, The second output end of the first existing traction transformer is connected to the busbar B through the circuit breaker QF3;

The second flexible traction transformer includes a circuit breaker QF6', a second energy-saving traction transformer, a circuit breaker QF8', a second matching transformer, a second three-phase-single-phase converter and Circuit breaker QF10', wherein the primary three-phase of the second energy-saving traction transformer is connected to the three-phase power grid through the circuit breaker QF6', and the secondary three-phase of the second energy-saving traction transformer is connected to the three-phase grid through the circuit breaker QF8 ' is connected with the primary three-phase of the second matching transformer, the secondary side of the second matching transformer is connected with the input end of the second three-phase-single-phase converter, and the second three-phase-single-phase transformer The output end of the current transformer is connected to the busbar A' through the circuit breaker QF10';

The second existing traction transformer, the input end of the second existing traction transformer is connected to the three-phase grid through the circuit breaker QF1', and the first output end of the second existing traction transformer is connected to the bus A through the circuit breaker QF2' ' connection, the second output end of the second existing traction transformer is connected to the busbar B' through the circuit breaker QF3';

Wherein, the first existing traction transformer, the first flexible traction transformer, the second flexible traction transformer, and the second existing traction transformer are arranged and connected to the busbar in sequence;

The system also includes a circuit breaker QF4, a circuit breaker QF5, a circuit breaker QF5', and a circuit breaker QF4'. The circuit breakers QF5' are located on both sides of the electrical split-phase b respectively, and the circuit breakers QF5' and QF4' are respectively located on both sides of the electrical split-phase c, wherein the electrical split-phase a and the electrical split-phase c are respectively flexible traction transformers. Substation 1 and flexible traction substation 2 are divided into electrical phases, the electrical phase b is the electrical phase separation between the flexible traction substation 1 and the flexible traction substation 2, and the electrical phase a is connected in parallel with a circuit breaker QF11, parallel circuit breaker QF12 at the electrical split phase b.

In the embodiment of the present application, the first energy-saving traction transformer is also connected to bus A and bus B through circuit breaker QF7, and the second energy-saving traction transformer is also connected to bus A' and bus B' through QF7'.

Among them, the first flexible traction transformer and its busbar, the first existing traction transformer and its busbar, circuit breaker QF4 and circuit breaker QF5 are composed of flexible traction substation 1, and the second flexible traction transformer and its busbar are composed of flexible traction substation 1. The busbar where it is located, the second existing traction transformer and the busbar where it is located, the circuit breaker QF4' and the circuit breaker QF5' constitute the flexible traction substation 2. The second existing traction transformer described in this system is in the system. During normal operation, the power supply arm on the QF3' side has been supplying power to the right side of the electrical split phase at c.

The present application also proposes a protection method for a flexible traction system, as shown in FIG. 2 , which is applied to the above-mentioned flexible traction power supply system, and the method includes the following steps:

Step S1, real-time monitoring of system circulation, electrical quantities at various places in the system, the working state of each circuit breaker and protection action signals, the working state includes tripping and closing, and the electrical quantities at various places in the system include the voltage and current at each circuit breaker. , the protection action signal includes protection action and protection inaction.

Specifically, circuit breakers are connected in parallel at both ends of the electrical split in the flexible traction substation 1 and between the flexible traction substation 1 and the flexible traction substation 2, and corresponding circuit breakers are installed at the feeder circuit breaker and the electrical split circuit breaker. The voltage and current transformers, optical cable communication channels and power directional elements are used to monitor the electric quantity information of the traction network power distribution phase. The communication channel can realize the mutual exchange of the electric quantity information, and realize the joint jumping of the circuit breakers in the substation and between the substations. Thereby, the system working state switching is realized.

Figure 1 is a schematic diagram of the structure of the flexible traction power supply system. Taking the flexible traction substation 1 as an example, when the energy-saving traction transformer fails, the protection action trips on QF6 and QF8; when the matching transformer fails or three-phase-single-phase When the converter system is faulty, the protection action is QF8, QF10 tripping; when the flexible traction substation busbar is faulty, the protection action is QF10, QF5 tripping; when the traction network is faulty, the protection action is QF5, QF11, QF12 tripping.

Through the protection action information of each part of the flexible traction power supply system and the action and tripping of the circuit breaker, the operation of the system equipment can be determined, and the basis for the system operation state can be provided, thereby ensuring the safe and stable power supply of the system.

As shown in Figure 3, it is a schematic diagram of the normal operation state of the flexible traction power supply system, which detects the electrical quantity and protection action status of the system. Circuit breaker QF5, circuit breaker QF11, circuit breaker QF12, circuit breaker QF6', circuit breaker QF8', circuit breaker QF10', circuit breaker QF5', circuit breaker QF1', circuit breaker QF3', circuit breaker QF4' are closed, and the rest of the circuit breakers are closed open, the flexible traction power supply system realizes long-distance power supply.

Step S2: Determine the faulty equipment based on the circulating current of the system, the electrical quantities of various parts of the system, the working state of each circuit breaker, and the protection action signal.

In the embodiment of the present application, in the step S2, the faulty equipment is determined based on the circulating current of the system, the electrical quantities in various parts of the system, the working state of each circuit breaker, and the protection action signal, which specifically includes:

(1) If the system circulating current is greater than the preset maximum limit, the system fails to connect to the grid;

(2) If the system has a protective action, the circuit breaker QF10 and the circuit breaker QF8, or the circuit breaker QF6 and the circuit breaker QF8 are tripped, and the circuit breaker QF10', QF6', circuit breaker QF5', circuit breaker QF5 and circuit breaker QF8 are tripped When both are closed, the first flexible traction transformer is faulty;

(3) If the system has a protection action, the circuit breaker QF10' and the circuit breaker QF8', or the circuit breaker QF6' and the circuit breaker QF8' are tripped, and the circuit breaker QF5', the circuit breaker QF5, the circuit breaker QF6, the circuit breaker When both the circuit breaker QF8 and the circuit breaker QF10 are closed, the second flexible traction transformer is faulty;

(4) If the system has a protection action, the circuit breaker QF10 and the circuit breaker QF5 are tripped, and the circuit breaker QF5', the circuit breaker QF10', the circuit breaker QF6', the circuit breaker QF8', the circuit breaker QF8 and the circuit breaker When both QF6 and QF6 are closed, it is the busbar fault at the first flexible traction transformer;

(5) If the system has a protection action, the circuit breaker QF10' and the circuit breaker QF5' are tripped, and the circuit breaker QF5, the circuit breaker QF10, the circuit breaker QF6, the circuit breaker QF8, the circuit breaker QF8' and the circuit breaker When both QF6' are closed, the busbar fault at the second flexible traction transformer;

(6) If the system has a protection action, when the circuit breaker QF10, the circuit breaker QF8, the circuit breaker QF10' and the circuit breaker QF8' are tripped and the circuit breaker QF5 and the circuit breaker QF5' are closed, or, the system is protected When circuit breaker QF6', circuit breaker QF8', circuit breaker QF6 and circuit breaker QF8 are tripped and circuit breaker QF5 and circuit breaker QF5' are closed, or, the system has protective action, circuit breaker QF6', circuit breaker QF8' When the circuit breaker QF8 and the circuit breaker QF10 are tripped and the circuit breaker QF5 and the circuit breaker QF5' are closed, or, the system has a protective action, the circuit breaker QF8', the circuit breaker QF10', the circuit breaker QF6 and the circuit breaker QF8 are tripped and open circuit When the circuit breaker QF5 and the circuit breaker QF5' are closed, both the first flexible traction transformer and the second flexible traction transformer are faulty;

(7) If the system has a protection action, the circuit breaker QF10 and circuit breaker QF5 are tripped and circuit breaker QF5', circuit breaker QF6, and circuit breaker QF8 are closed, and at the same time, circuit breaker QF10' and circuit breaker QF8' are tripped, or , the system has a protection action, when the circuit breaker QF6' and the circuit breaker QF8' are tripped, the busbar at the first flexible traction transformer is faulty and the second flexible traction transformer is faulty;

(8) If the system has a protection action, the circuit breaker QF10' and the circuit breaker QF5' are tripped and the circuit breaker QF5, the circuit breaker QF6', and the circuit breaker QF8' are closed, and at the same time, the circuit breaker QF10 and the circuit breaker QF8 are tripped, Or when the circuit breaker QF6 and the circuit breaker QF8 are tripped, the first flexible traction transformer is faulty and the busbar at the second flexible traction transformer is faulty;

(9) If the system has a protection action, the circuit breaker QF10, circuit breaker QF5, circuit breaker QF5' and circuit breaker QF10' are all tripped and circuit breaker QF6, circuit breaker QF6', circuit breaker QF8, circuit breaker QF8' are all tripped When closed, the busbar at the first flexible traction transformer is faulty and the busbar at the second flexible traction transformer is faulty;

(10) If the electrical quantity at the circuit breaker QF5 or the circuit breaker QF5' reaches the set protection action value and meets the fault direction condition, the circuit breaker QF10, the circuit breaker QF10', the circuit breaker QF6, the circuit breaker QF6', the circuit breaker QF10', the circuit breaker QF6', the circuit breaker When both the circuit breaker QF8 and the circuit breaker QF8' are closed and no protection action signal is sent, it is a catenary fault.

Step S3: Control each circuit breaker according to the faulty device.

In the embodiment of the present application, the step S3 is specifically as follows:

If the fault is the failure of the system to be connected to the grid, the circuit breaker QF12 will be disconnected, so that the first flexible traction transformer can supply power between the electrical split-phase a and electrical split-phase b and the power supply arm on the left side of electrical split-phase a, so that the second flexible traction transformer can supply power The flexible traction transformer supplies power to the power supply arm on the right side of the electrical split phase b;

Specifically, before or during the normal operation of the system, it is also necessary to monitor whether the circulating current of the system exceeds the preset limit value. If so, it means that the two flexible traction transformers have failed to connect to the grid, and the system enters the disconnected working state. If the fault is the system If the grid connection fails, the circuit breaker QF12 is disconnected, so that the first flexible traction transformer supplies power between the electrical split phase a and the electrical split phase b and the power supply arm on the left side of the electrical split phase a, so that the second traction transformer is the electrical split phase The power supply arm on the right side of b is powered, that is, the circuit breaker QF12 is disconnected, the electrical phase at b is put into operation again, and each power supply arm is powered by the corresponding flexible traction transformer. Among them, the power supply arm on the left side of the electrical split phase b is powered by the flexible traction transformer of flexible traction substation 1, and the power supply arm bc is powered by the flexible traction transformer of flexible traction substation 2. As shown in Figure 11, the flexible traction power supply system is de-networked and operated. Status diagram.

If the fault is the fault of the first flexible traction transformer, closing the circuit breaker QF1 and the circuit breaker QF2;

If the fault is the fault of the second flexible traction transformer, closing the circuit breaker QF2';

Specifically, Fig. 4 is a schematic diagram of the operation state of the first flexible traction transformer fault, which realizes the reconfiguration operation of the system in the case of a single flexible traction transformer fault (the same is true when the flexible traction transformer in the flexible traction substation 2 fails) , to ensure the normal operation of the locomotive.

When the system protection operates, the circuit breaker QF10 and the circuit breaker QF8 or the circuit breaker QF6 and the circuit breaker QF8 are tripped and the circuit breaker QF10′, circuit breaker QF6′, circuit breaker QF5′, circuit breaker QF5 and circuit breaker QF8′ are closed, the judgment is only It is the fault of the flexible traction transformer in flexible traction substation 1, that is, the first flexible traction transformer, the circuit breaker QF1 and the circuit breaker QF2 of flexible traction substation 1 are closed, and the flexible traction transformer of flexible traction substation 2 is also the second flexible traction transformer. The traction transformer and the flexible traction substation 1 have the existing traction transformer, that is, the second existing traction transformer, and one power supply arm is connected to the grid to supply power to the traction grid together, so as to realize the normal operation of the flexible traction power supply system after reconstruction when a single flexible traction transformer fails ;When the system protection action, circuit breaker QF10' and circuit breaker QF8' or circuit breaker QF6' and circuit breaker QF8' trip and circuit breaker QF5', circuit breaker QF5, circuit breaker QF6, circuit breaker QF8, circuit breaker QF10 are closed, The flexible traction transformer of flexible traction substation 2 is faulty, the circuit breaker QF2' of flexible traction substation 2 is closed, and the existing traction transformer of flexible traction substation 2 and the flexible traction transformer of sexual traction substation 1 are connected to the grid together to the traction Grid power supply to realize the normal operation of the flexible traction power supply system after reconstruction when a single flexible traction transformer fails.

If the fault is a busbar fault at the first flexible traction transformer, controlling the second flexible traction transformer to supply power to the power supply section of the system;

If the fault is a busbar fault at the second flexible traction transformer, controlling the first flexible traction transformer to supply power to the power supply section of the system;

Specifically, as shown in FIG. 5 , it is a schematic diagram of the operation state when the bus of the flexible traction substation 1 is faulty, that is, the bus at the first flexible traction transformer is faulty as an example, to realize the system when the bus of a single flexible traction substation is faulty Reconstruction can make the locomotive pass through with reduced power.

When the system protection acts, the circuit breakers QF10 and QF5 are both tripped and QF5', QF10', QF6', QF8', QF8, QF6 are closed, it is judged that the flexible traction substation 1 bus is faulty. At this time, only the flexible traction transformer The flexible traction transformer in the power station 2 supplies power to the power supply section of the system; when the system protection action, the circuit breakers QF10' and QF5' are both tripped and QF5, QF10, QF6, QF8, QF8', QF6' are closed, it is judged to be flexible The busbar of traction substation 2 is faulty. At this time, only the flexible traction transformer in flexible traction substation 1 is used to supply power to the power supply section of the system.

If the fault is that both the first flexible traction transformer and the second flexible traction transformer are faulty, the circuit breaker QF11 and the circuit breaker QF12 are both disconnected, so that the system returns to the existing traction power supply state;

Specifically, as shown in FIG. 6 , it is a schematic diagram of the operating state when both the first flexible traction transformer and the second flexible traction transformer are faulty. The electrical quantities and protection action states of various parts of the system are detected. During the protection action of the system, the circuit breaker QF10 ′ and the circuit breaker When QF8′ or circuit breaker QF6′ and circuit breaker QF8′ are tripped and circuit breaker QF10 and circuit breaker QF8 or circuit breaker QF6 and circuit breaker QF8 are tripped and circuit breaker QF5 and circuit breaker QF5′ are closed, all flexible traction transformers are faulty The circuit breaker QF11 and the circuit breaker QF12 are opened, and all electrical phases are put into use again, and the system returns to the state of the existing traction power supply system. If the circuit breaker QF6 of the circuit breaker is closed, it is judged that the energy-saving traction transformer is not faulty, and the energy-saving traction transformer is used to realize the existing traction power supply. All existing traction transformers realize power supply by existing traction power supply, and the specific conditions are as follows:

For flexible traction substation 1, if the circuit breaker QF6 is in the closed state, it is judged that the energy-saving traction transformer is normal, and the circuit breaker QF7 is closed to use the energy-saving traction transformer of flexible traction substation 1 to realize the existing traction power supply; If the circuit breaker QF6 is in the disconnected state, the energy-saving traction transformer is judged to be faulty, and the circuit breaker QF1, the circuit breaker QF2, the circuit breaker QF3, and the circuit breaker QF4 are closed, and the existing traction transformer is used to realize the existing traction power supply mode to supply power to the traction network; In flexible traction substation 2, if the circuit breaker QF6' is in the closed state, it is judged that the energy-saving traction transformer is normal, the circuit breaker QF7' is closed, the circuit breaker QF1' and the circuit breaker QF3' are opened, and the flexible traction substation 2 saves energy. If the circuit breaker QF6' is in the open state, it is judged that the energy-saving traction transformer is faulty, the circuit breaker QF2' is closed, and the existing traction transformer is used to realize the existing traction power supply mode to supply power to the traction network.

If the fault is the fault of the busbar at the first flexible traction transformer and the fault of the second flexible traction transformer, the circuit breaker QF2' is closed, so that the second existing traction transformer supplies power to the through power supply section;

Specifically, Fig. 7 is a schematic diagram of the system operation when the busbar at the first flexible traction transformer is faulty and the second flexible traction transformer is faulty. During the system protection action, the circuit breaker QF10 and the circuit breaker QF5 are both tripped and the circuit breaker QF5' and the circuit breaker are open. When circuit breaker QF6 and circuit breaker QF8 are closed, and circuit breaker QF10' and circuit breaker QF8' or circuit breaker QF6' and circuit breaker QF8' are tripped, it is judged that the flexible traction substation 1 busbar is faulty and the flexible traction substation 2 flexible traction transformer At this time, the circuit breaker QF2' is closed, and the existing traction transformer of the flexible traction substation 2 supplies power to the long-distance power supply section, and the locomotive runs with reduced power.

If the fault is the fault of the first flexible traction transformer and the fault of the bus at the second flexible traction transformer, the circuit breaker QF1, the circuit breaker QF2, the circuit breaker QF3 and the circuit breaker QF4 are closed, and the circuit breaker QF11 is opened, so that the first 1. The existing traction transformer supplies power to the traction network;

Specifically, Fig. 8 is a schematic diagram of the system operation when the first flexible traction transformer is faulty and the busbar at the second flexible traction transformer is faulty. During the system protection action, the circuit breaker QF10' and the circuit breaker QF5' are both tripped and the circuit breakers QF5, When the circuit breaker QF6' and the circuit breaker QF8' are closed, and the circuit breaker QF10 and the circuit breaker QF8 or the circuit breaker QF6 and the circuit breaker QF8 are tripped, it is judged that the flexible traction substation 2 busbar is faulty and the flexible traction substation 1 flexible traction transformer is faulty , at this time, circuit breaker QF1, circuit breaker QF2, circuit breaker QF3, circuit breaker QF4 are closed, circuit breaker QF11 is opened, the flexible traction substation 1 is powered by the existing traction transformer, and the locomotive runs at reduced power.

If the fault is a bus failure at the first flexible traction transformer and a bus failure at the second flexible traction transformer, stopping the system;

Specifically, Fig. 9 is a schematic diagram of the system when the busbar at the first flexible traction transformer is faulty and the busbar at the second flexible traction transformer is faulty. During the system protection action, the circuit breaker QF10 and the circuit breaker QF5 are both disconnected and the circuit breaker QF5' . When the circuit breaker QF10' is disconnected, both the busbars of the two flexible traction substations are faulty, the flexible traction power supply system is faulty, and the system stops running.

If the fault is a catenary fault, control the corresponding circuit breaker to close or open according to the position of the catenary fault.

In the embodiment of the present application, if the fault is a catenary fault, the corresponding circuit breaker is controlled to be closed or opened according to the position of the catenary fault, as follows:

Determine the fault location;

If the catenary fault is located on the left side of the electrical split phase a, disconnect the circuit breaker QF11;

If the catenary fault is located between the electrical sub-phase a and the electrical sub-phase b, the circuit breaker QF11, the circuit breaker QF12 and the circuit breaker QF5 are opened, and the circuit breaker QF1, the circuit breaker QF3 and the circuit breaker QF4 are closed, so as to The left side of the electrical split phase a is powered by the first existing traction transformer, and the second flexible traction transformer is powered between the electrical split phase b and the electrical split phase c;

If the catenary fault is located between the electrical split phase b and the electrical split phase c, the circuit breaker QF12 and the circuit breaker QF5' are disconnected, so that the power supply arm on the left side of the electrical split phase b is powered by the first flexible traction transformer .

Specifically, as shown in FIG. 10, it is a schematic diagram of the system operation state when the catenary ab segment of the flexible traction power supply system is faulty as an example. During the system protection action, if the electrical quantity measured at the circuit breaker QF5 or the circuit breaker QF5' reaches When the set protection action value and the fault direction condition are met, and the circuit breaker QF10, circuit breaker QF10′, circuit breaker QF6, circuit breaker QF6′, circuit breaker QF8, circuit breaker QF8′ are all closed at the same time, it is judged as a catenary fault. The directional elements at circuit breaker QF5, circuit breaker QF5', circuit breaker QF11, and circuit breaker QF12 detect the direction of the fault, and act on the corresponding circuit breaker to isolate the fault in the fault section and reduce the impact of the fault on the system operation. details as following:

When the fault occurs on the left side of the electrical split phase a, the circuit breaker QF11 is disconnected, and the fault is isolated on the left power supply arm of the electrical split phase a, and the right power supply arm of the electrical split phase a is connected by the flexible traction substation 1 and the flexible traction substation. The 2 flexible traction transformers supply power normally; when the fault occurs in the ab section, the circuit breaker QF11, the circuit breaker QF12, and the circuit breaker QF5 are opened, and the fault is isolated in the ab power supply arm, the circuit breaker QF1, the circuit breaker QF3, and the circuit breaker QF4 are closed, and the power The left power supply arm of split-phase a is normally powered by the existing traction transformer of flexible traction substation 1, and the power supply arm bc is normally powered by the flexible traction transformer of flexible traction substation 2; when the fault occurs in section bc, the circuit breaker QF12, circuit breaker QF5' is disconnected, the fault is isolated in the bc section, and the power supply arm on the left side of the electrical split phase b is normally powered by the flexible traction substation 1 transformer.

Those of ordinary skill in the art will appreciate that the embodiments described herein are intended to assist readers in understanding the principles of the present invention, and it should be understood that the scope of protection of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations without departing from the essence of the present invention according to the technical teaching disclosed in the present invention, and these modifications and combinations still fall within the protection scope of the present invention.

Claims (5)

1. A flexible traction power supply system, the system comprising:

the system comprises a first flexible traction transformer, a second flexible traction transformer and a third flexible traction transformer, wherein the first flexible traction transformer comprises a breaker QF6, a first energy-saving traction transformer, a breaker QF8, a first matching transformer, a first three-phase-single-phase converter and a breaker QF10 which are sequentially connected, the primary side three phase of the first energy-saving traction transformer is connected with a three-phase power grid through the breaker QF6, the secondary side three phase of the first energy-saving traction transformer is connected with the primary side three phase of the first matching transformer through a breaker QF8, the secondary side of the first matching transformer is connected with the input end of the first three-phase-single-phase converter, and the output end of the first three-phase-single-phase converter is connected with a bus A through the breaker QF 10;

the system comprises a first existing traction transformer, a second existing traction transformer and a third existing traction transformer, wherein the input end of the first existing traction transformer is connected with a three-phase power grid through a breaker QF1, the first output end of the first existing traction transformer is connected with a bus A through a breaker QF2, and the second output end of the first existing traction transformer is connected with a bus B through a breaker QF 3;

the second flexible traction transformer comprises a breaker QF6', a second energy-saving traction transformer, a breaker QF8', a second matching transformer, a second three-phase single-phase converter and a breaker QF10' which are sequentially connected, wherein the primary side three phase of the second energy-saving traction transformer is connected with a three-phase power grid through the breaker QF6', the secondary side three phase of the second energy-saving traction transformer is connected with the primary side three phase of the second matching transformer through the breaker QF8', the secondary side of the second matching transformer is connected with the input end of the second three-phase single-phase converter, and the output end of the second three-phase single-phase converter is connected with a bus A ' through the breaker QF10 ';

the input end of the second existing traction transformer is connected with the three-phase power grid through a breaker QF1 ', the first output end of the second existing traction transformer is connected with the bus A ' through a breaker QF2 ', and the second output end of the second existing traction transformer is connected with the bus B ' through a breaker QF3 ';

the first existing traction transformer, the first flexible traction transformer, the second flexible traction transformer and the second existing traction transformer are sequentially connected to a bus in an arrayed manner;

the system further comprises a breaker QF4, a breaker QF5, a breaker QF5' and a breaker QF4 ', wherein the breaker QF4 and the breaker QF5 are respectively positioned on two sides of the electric phase separation a, the breaker QF5 and the breaker QF5' are respectively positioned on two sides of the electric phase separation b, and the breaker QF5' and the breaker QF4 ' are respectively positioned on two sides of the electric phase separation c, wherein the electric phase separation a and the electric phase separation c are respectively an electric phase separation in the flexible traction substation 1 and the flexible traction substation 2, the electric phase separation b is an electric phase separation between the flexible traction substation 1 and the flexible traction substation 2, the electric phase separation a is connected with the breaker QF11 in parallel, and the breaker QF12 is connected with the electric phase separation b in parallel;

the first energy-saving traction transformer is further connected with the bus A and the bus B through a breaker QF7, and the second energy-saving traction transformer is further connected with the bus A ' and the bus B ' through QF7 '.

2. A method for protecting a flexible traction power supply system, which is applied to the flexible traction power supply system according to claim 1, and comprises the following steps:

s1, real-time monitoring of system circulation, electrical quantities of all parts of the system, working states of all circuit breakers and protection action signals, wherein the working states comprise tripping and closing, the electrical quantities of all parts of the system comprise voltage and current quantities of all circuit breakers, and the protection action signals comprise protection actions and protection inactions;

s2, determining fault equipment based on system circulation, electrical quantities of all parts of the system, working states of all circuit breakers and protection action signals;

and S3, controlling each breaker according to the fault equipment.

3. The method for protecting a flexible traction power supply system according to claim 2, wherein the step S2 determines a fault device based on the system circulation, the electrical quantities of various parts of the system, the operating states of various circuit breakers, and the protection action signal, which includes:

if the system circulation is larger than a preset maximum limit value, the system is failed to be connected to the grid;

if the system has protection actions, the circuit breaker QF10 and the circuit breaker QF8 or the circuit breaker QF6 and the circuit breaker QF8 trip, and the circuit breaker QF10', the QF6', the circuit breaker QF5', the circuit breaker QF5 and the circuit breaker QF8' are closed, the fault is the fault of the first flexible traction transformer;

if the system has protection action, the breaker QF10' and the breaker QF8' or the breaker QF6' and the breaker QF8' trip, and the breaker QF5', the breaker QF5, the breaker QF6, the breaker QF8 and the breaker QF10 are closed, the system is a second flexible traction transformer fault;

if the system has protection action, the breaker QF10 trips to a breaker QF5, and when the breaker QF5', the breaker QF10', the breaker QF6', the breaker QF8', the breaker QF8 and the breaker QF6 are closed, the bus fault at the first flexible traction transformer is detected;

if the system has protection action, the breaker QF10 'and the breaker QF5' trip, and the breaker QF5, the breaker QF10, the breaker QF6, the breaker QF8, the breaker QF8 'and the breaker QF6' are all closed, the bus fault at the second flexible traction transformer is detected;

if the system has a protection action, when the circuit breaker QF10, the circuit breaker QF8, the circuit breaker QF10 'and the circuit breaker QF8' trip and the circuit breaker QF5 and the circuit breaker QF5 'are closed, or when the system has a protection action, the circuit breaker QF6', the circuit breaker QF8', the circuit breaker QF6 and the circuit breaker QF8 trip and the circuit breaker QF5 and the circuit breaker QF5' are closed, or when the system has a protection action, the circuit breaker QF6', the circuit breaker QF8', the circuit breaker QF8 and the circuit breaker QF10 trip and the circuit breaker QF5 and the circuit breaker QF5 'are closed, or when the system has a protection action, the circuit breaker 8', the circuit breaker QF10', the circuit breaker QF6 and the circuit breaker QF8 trip and the circuit breaker QF5 and the circuit breaker QF5', the first flexible traction transformer and the second flexible traction transformer are both failed;

if the system has protection actions, the breaker QF10 trips to the breaker QF5, the breaker QF5', the breaker QF6 and the breaker QF8 are closed, and meanwhile, the breaker QF10' trips to the breaker QF8', or if the system has protection actions, when the breaker QF6' trips to the breaker QF8', the system is in bus fault at the first flexible traction transformer and fault at the second flexible traction transformer;

if the system has protection actions, the breaker QF10 'and the breaker QF5' trip, the breaker QF5, the breaker QF6 'and the breaker QF8' close, and meanwhile, the breaker QF10 and the breaker QF8 trip, or the breaker QF6 and the breaker QF8 trip, the system is a fault of a first flexible traction transformer and a fault of a bus at the position of a second flexible traction transformer;

if the system has protection actions, when the breaker QF10, the breaker QF5, the breaker QF5 'and the breaker QF10' trip and the breaker QF6, the breaker QF6', the breaker QF8 and the breaker QF8' are closed, the bus at the first flexible traction transformer fails and the bus at the second flexible traction transformer fails;

and if the electric quantity at the breaker QF5 or the breaker QF5 'reaches a set protection action value and meets the fault direction condition, and meanwhile, the breaker QF10, the breaker QF10', the breaker QF6, the breaker QF6', the breaker QF8 and the breaker QF8' are closed and no protection action signal is sent, the fault of the contact network is determined.

4. The method for protecting the flexible traction power supply system according to claim 3, wherein the step S3 is as follows:

if the fault is grid connection failure of the system, the breaker QF12 is disconnected, the first flexible traction transformer supplies power for the power supply arms between the split phase a and the split phase b and on the left side of the split phase a, and the second flexible traction transformer supplies power for the power supply arm on the right side of the split phase b;

if the fault is the fault of the first flexible traction transformer, closing the circuit breaker QF1 and the circuit breaker QF 2;

if the fault is the fault of the second flexible traction transformer, closing the circuit breaker QF 2';

if the fault is a bus fault at the first flexible traction transformer, controlling the second flexible traction transformer to supply power for a system through power supply section;

if the fault is a bus fault at the second flexible traction transformer, controlling the first flexible traction transformer to supply power for a system through power supply section;

if the faults are faults of both the first flexible traction transformer and the second flexible traction transformer, both the breaker QF11 and the breaker QF12 are disconnected, so that the system returns to the existing traction power supply state;

if the fault is a bus fault at the first flexible traction transformer and a fault of the second flexible traction transformer, closing a breaker QF 2' to enable the second existing traction transformer to supply power for the through power supply section;

if the fault is the fault of the first flexible traction transformer and the bus fault of the second flexible traction transformer, closing the circuit breaker QF1, the circuit breaker QF2, the circuit breaker QF3 and the circuit breaker QF4, and disconnecting the circuit breaker QF11 so as to enable the first existing traction transformer to supply power for the traction network;

if the fault is a bus fault at the first flexible traction transformer and a bus fault at the second flexible traction transformer, stopping the system;

and if the fault is the contact network fault, controlling the corresponding breaker to be closed or opened according to the fault position of the contact network.

5. The protection method for the flexible traction power supply system according to claim 4, wherein if the fault is a catenary fault, the corresponding circuit breaker is controlled to be closed or opened according to a catenary fault position, specifically as follows:

judging a fault position;

if the contact network fault is positioned on the left side of the electric phase separation a, the breaker QF11 is disconnected;

if the contact network fault is located between the electric split phase a and the electric split phase b, the breaker QF11, the breaker QF12 and the breaker QF5 are disconnected, the breaker QF1, the breaker QF3 and the breaker QF4 are closed, so that the left side of the electric split phase a is powered by a first existing traction transformer, and the electric split phase b and the electric split phase c are powered by a second flexible traction transformer;

and if the contact network fault is positioned between the electrical split phase b and the electrical split phase c, disconnecting the breaker QF12 and the breaker QF5' so that the power supply arm on the left side of the electrical split phase b is supplied with power by the first flexible traction transformer.

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