Direct-current traction network differential protection system and bilateral traction network power supply system

Abstract

The utility model discloses a direct current traction network differential protection system and a bilateral traction network power supply system, and belongs to the technical field of urban rail transit direct current traction network protection. According to the utility model, the wireless communication module feeds back the running states of the direct-current traction network and the subway vehicle to the subway running control center in a low-delay manner, so that the running control center can solve problems at the first time, and conditions are provided for data communication between the direct-current traction network and the subway vehicle; the method facilitates the establishment of a protection method in a subsequent protection system, reduces the cost of the protection system, and improves the protection efficiency. And the characteristic wave injection module is introduced, and active protection of the subway direct current traction network is realized by injecting characteristic waves into the direct current traction network, so that the fault characteristics are more different than those under other conditions, and the protection sensitivity is further improved.

Description

Technical Field

[0001] The utility model relates to a direct current traction network differential protection system and a bilateral traction network power supply system, belonging to the technical field of direct current traction network protection for urban rail transit. Background Art

[0002] The DC traction network is a facility arranged along the subway line that is specifically used to provide electrical energy for subway vehicles. It forms a complete power supply path through the "positive DC feeder - contact network - subway vehicle - running rail - negative return line" and is equipped with fault detection, protection and communication devices. Among them, the protection system plays a vital role in ensuring the safe and reliable operation of rail transit.

[0003] The most common DC traction network protection system in the bilateral DC traction power supply system is the main protection + bilateral joint protection, which relies on the laid optical fiber communication to make up for the shortcomings of the main protection remote protection and realize the protection of the entire line by combining multiple protection strategies. However, the detection object of this protection system is the current amplitude. When the subway starts, the increase in current can easily cause the nearby DC traction network protection system to malfunction; at the same time, optical fiber needs to be laid in advance, and the establishment and maintenance of optical fiber channels require extremely high costs. Therefore, it is necessary to propose a fast, reliable and low-maintenance DC traction network protection system. Utility Model Content

[0004] In order to solve the above problems, the utility model provides a DC traction network differential protection system and a bilateral traction network power supply system, and the technical solutions are as follows:

[0005] The DC traction network differential protection system of the utility model comprises: a first protection device 3, a first characteristic wave injection device 5, a first current detector 7, a first data processing module 9, a second protection device 4, a second characteristic wave injection device 6, a second current detector 8, a second data processing module 10, a third current detector 13 and a third data processing module 14;

[0006] The first protection device 3, the first characteristic wave injection device 5, and the first current detector 7 are connected in series to the first DC feeder 19, the first protection device 3 and the first characteristic wave injection device 5 are respectively connected to the first wireless communication module 11, and the first current detector 7 is connected to the first wireless communication module 11 through the first data processing module 9;

[0007] The second protection device 4, the second characteristic wave injection device 6, and the second current detector 8 are connected in series to the second DC feeder 20, the second protection device 4 and the second characteristic wave injection device 6 are respectively connected to the second wireless communication module 12, and the second current detector 8 is connected to the second wireless communication module 12 through the second data processing module 10;

[0008] The third current detector 13 and the vehicle electrical equipment 16 are installed in series in the subway vehicle, and the third current detector 13 is connected to the third wireless communication module 15 through the third data processing module 14;

[0009] The first wireless communication module 11 , the second wireless communication module 12 , and the third wireless communication module 15 are in communication connection with a subway operation control center (OCC) 17 .

[0010] In one implementation, the first wireless communication module 11, the second wireless communication module 12, and the third wireless communication module 15 are 5G communication modules.

[0011] In one embodiment, the protection device is a differential protection device, which may be composed of components such as a protection relay, a circuit breaker, an isolating switch and a control circuit.

[0012] In one embodiment, the data processing module is a microprocessor, which may be composed of components such as a signal sampler, a digital filter, and a data storage device.

[0013] In one embodiment, the installation position sequence of the first protection device 3, the first characteristic wave injection device 5, and the first current detector 7 on the first DC feeder 19 is consistent with the power supply direction of the first DC traction network.

[0014] In one embodiment, the installation position sequence of the second protection device 4, the second characteristic wave injection device 6, and the second current detector 8 on the second DC feeder 20 is consistent with the power supply direction of the second DC traction network.

[0015] The utility model discloses a bilateral traction network power supply system for supplying power to subway vehicles, comprising: a first traction substation 1, a second traction substation 2 and a DC traction network;

[0016] The DC traction network includes: a first DC feeder 19, a second DC feeder 20, a contact network 21, a running rail 22, a first return line 23, and a second return line 24;

[0017] The first traction substation 1 is connected to the overhead contact network 21 through the first DC feeder 19; the second traction substation 2 is connected to the overhead contact network 21 through the second DC feeder 20; the overhead contact network 21 is connected to the subway vehicle 18; the subway vehicle 18 is connected to the running rail 22; the running rail 22 is connected to the first traction substation 1 and the second traction substation 2 through the first return line 23 and the second return line 24 respectively;

[0018] The first DC feeder 19 is connected in series with a first protection device 3, a first characteristic wave injection device 5, and a first current detector 7 in sequence. The first protection device 3 and the first characteristic wave injection device 5 are respectively connected to the first wireless communication module 11, and the first current detector 7 is connected to the first wireless communication module 11 through the first data processing module 9.

[0019] The second DC feeder 20 is connected in series with a second protection device 4, a second characteristic wave injection device 6, and a second current detector 8 in sequence. The second protection device 4 and the second characteristic wave injection device 6 are respectively connected to the second wireless communication module 12, and the second current detector 8 is connected to the second wireless communication module 12 through the second data processing module 10.

[0020] The subway vehicle 18 is connected in series with a third current detector 13 and a vehicle electrical device 16, and the third current detector 13 is connected to a third wireless communication module 15 via a third data processing module 14;

[0021] The first wireless communication module 11 , the second wireless communication module 12 , and the third wireless communication module 15 are in communication connection with a subway operation control center 17 .

[0022] In one implementation, the first wireless communication module 11, the second wireless communication module 12, and the third wireless communication module 15 are 5G communication modules.

[0023] In one embodiment, the first traction substation 1 and the second traction substation 2 convert 35 kV AC power into 1500 V DC power for use in subway vehicles.

[0024] Advantages of the utility model:

[0025] 1. The DC traction network differential protection system of the utility model can feed back the operating status of the DC traction network and subway vehicles to the subway operation control center (OCC) with low latency through the wireless communication module, so that the operation control center can solve problems as soon as they occur. At the same time, it provides conditions for data communication between the DC traction network and subway vehicles, so as to facilitate the establishment of protection methods in the subsequent protection system, reduce the cost of the protection system, and improve the efficiency of protection.

[0026] 2. The DC traction network differential protection system of the utility model introduces a characteristic wave injection module. By injecting characteristic waves into the DC traction network, active protection of the subway DC traction network is achieved, making the fault characteristics more different than under other conditions, thereby improving the sensitivity of the protection.

[0027] 3. The protection system for the DC traction network uses differential protection as the main protection and bilateral trip protection as the auxiliary protection measures. It utilizes the characteristic wave current differential protection on the DC traction network and the subway incoming line, which can effectively protect the entire line and avoid false protection operations caused by the subway starting current, ensuring the reliability of protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a structural diagram of the subway bilateral DC traction power supply system of the utility model.

[0029] Figure 2 This is a communication and data flow diagram of the bilateral traction network power supply system of the utility model.

[0030] Figure 3 This is a working principle diagram of the bilateral traction network power supply system of the utility model.

[0031] In the figure: 1-first traction substation, 2-second traction substation, 3-first protection device, 4-second protection device, 5-first characteristic wave injection device, 6-second characteristic wave injection device, 7-first current detector, 8-second current detector, 9-first data processing module, 10-second data processing module, 11-first wireless communication module, 12-second wireless communication module, 13-third current detector, 14-third data processing module, 15-third wireless communication module, 16-vehicle electrical equipment, 17-subway operation control center, 18-subway vehicle, 19-first DC feeder, 20-second DC feeder, 21-contact network, 22-running rail, 23-first return line, 24-second return line.

[0032] In the figure: dotted line - communication connection. DETAILED DESCRIPTION

[0033] The following is a specific description of the utility model.

[0034] Example 1

[0035] This embodiment provides a DC traction network differential protection system, such as Figure 1 As shown, the differential protection system includes: a first protection device 3, a first characteristic wave injection device 5, a first current detector 7, a first data processing module 9, a second protection device 4, a second characteristic wave injection device 6, a second current detector 8, a second data processing module 10, a third current detector 13 and a third data processing module 14;

[0036] The first protection device 3, the first characteristic wave injection device 5, and the first current detector 7 are connected in series to the first DC feeder 19, the first protection device 3 and the first characteristic wave injection device 5 are respectively connected to the first wireless communication module 11, and the first current detector 7 is connected to the first wireless communication module 11 through the first data processing module 9;

[0037] The second protection device 4, the second characteristic wave injection device 6, and the second current detector 8 are connected in series to the second DC feeder 20, the second protection device 4 and the second characteristic wave injection device 6 are respectively connected to the second wireless communication module 12, and the second current detector 8 is connected to the second wireless communication module 12 through the second data processing module 10;

[0038] The third current detector 13 and the vehicle electrical equipment 16 are installed in series in the subway vehicle, and the third current detector 13 is connected to the third wireless communication module 15 through the third data processing module 14;

[0039] The first wireless communication module 11 , the second wireless communication module 12 , and the third wireless communication module 15 are in communication connection with a subway operation control center (OCC) 17 .

[0040] The protection device in this embodiment is a differential protection device, which can be implemented by a combination of a protection relay, a circuit breaker, an isolating switch and a control circuit.

[0041] The characteristic wave injection device in this embodiment is a power electronic converter, and an isolated single-phase inverter can be used.

[0042] The data processing module in this embodiment is a microprocessor, which can be implemented by combining a signal sampler, a digital filter and a data storage device.

[0043] Embodiment 2:

[0044] This embodiment provides a bilateral traction network power supply system for powering subway vehicles, such as Figure 1 As shown, it includes: a first traction substation 1, a second traction substation 2 and a DC traction network;

[0045] The DC traction network includes: a first DC feeder 19, a second DC feeder 20, a contact network 21, a running rail 22, a first return line 23, and a second return line 24;

[0046] The first traction substation 1 is connected to the overhead line 21 through the first DC feeder 19; the second traction substation 2 is connected to the overhead line 21 through the second DC feeder 20; the overhead line 21 is connected to the subway vehicle 18; the subway vehicle 18 is connected to the running rail 22; the running rail 22 is connected to the first traction substation 1 and the second traction substation 2 through the first return line 23 and the second return line 24 respectively;

[0047] The first DC feeder 19 is connected in series with a first protection device 3, a first characteristic wave injection device 5, and a first current detector 7 in the positive direction of the current. The first protection device 3 and the first characteristic wave injection device 5 are connected to the first wireless communication module 11 respectively, and the first current detector 7 is connected to the first wireless communication module 11 through the first data processing module 9.

[0048] The second DC feeder 20 is connected in series with a second protection device 4, a second characteristic wave injection device 6, and a second current detector 8 in the positive direction of the current. The second protection device 4 and the second characteristic wave injection device 6 are connected to the second wireless communication module 12 respectively, and the second current detector 8 is connected to the second wireless communication module 12 through the second data processing module 10.

[0049] A third current detector 13 and a vehicle electrical device 16 are connected in series in the subway vehicle 18, and the third current detector 13 is connected to the third wireless communication module 15 via the third data processing module 14;

[0050] The first wireless communication module 11 , the second wireless communication module 12 , and the third wireless communication module 15 are in communication connection with a subway operation control center (OCC) 17 .

[0051] In this embodiment, the first wireless communication module 11, the second wireless communication module 12, and the third wireless communication module 15 all adopt 5G communication modules.

[0052] The protection device in this embodiment is a differential protection device, which can be implemented by a combination of a protection relay, a circuit breaker, an isolating switch and a control circuit.

[0053] The characteristic wave injection device in this embodiment is a power electronic converter, and an isolated single-phase inverter can be used.

[0054] The data processing module in this embodiment is a microprocessor, which can be implemented by combining a signal sampler, a digital filter and a data storage device.

[0055] The working principle of this embodiment:

[0056] The data flow relationship of the DC traction network differential protection system or bilateral traction network power supply system of the utility model during operation is as follows: Figure 2As shown, the first current detector 7 measures the first current on the first DC feeder 19, and the current data is extracted by the first data processing module 9 to inject the first characteristic wave injected by the first characteristic wave injection device 5 into the first DC feeder 19, and the first data processing module 9 transmits the first current and the first characteristic wave to the first 5G communication module 11, the second current detector 8 measures the second current on the second DC feeder 20, and the current data is extracted by the second data processing module 10 to inject the second characteristic wave injected by the second characteristic wave injection device 6 into the second DC feeder 20, and the second data processing module 10 transmits the second current and the second characteristic wave to the second 5G communication module 12, the third current detector 13 measures the third current flowing through the subway vehicle electrical equipment 16, and the current data is extracted by the third data processing module 14 to inject the first characteristic wave and the second characteristic wave, and the third data processing module 14 transmits the first characteristic wave and the second characteristic wave to the first 5G communication module 12. Three 5G communication modules 15, the first 5G communication module 11, the second 5G communication module 12, and the third 5G communication module 15 transmit data to the subway operation control center (OCC) 17, which calculates and analyzes, and sends out the first protection device 3 action signal, the second protection device 4 action signal, the first characteristic wave injection device 5 start signal, and the second characteristic wave injection device 6 start signal according to the situation. The first protection device 3 action signal and the first characteristic wave injection device 5 are transmitted to the first 5G communication module 11, and then transmitted to the first protection device 3 and the first characteristic wave injection device 5 by the first 5G communication module 11 respectively. The second protection device 4 action signal and the second characteristic wave injection device 6 are transmitted to the second 5G communication module 12, and then transmitted to the second protection device 4 and the second characteristic wave injection device 6 by the second 5G communication module 12 respectively, so as to achieve the purpose of real-time monitoring and rapid protection.

[0057] like Figure 3 The working principle diagram of the present embodiment is shown. The first current detector 7 and the second current detector 8 are used to measure the first current on the first DC feeder 19 and the second current on the second DC feeder 20 respectively. After the first current and the second current are found to be abnormal, the first characteristic wave injection device 5 and the second characteristic wave injection device 6 are started. After a certain delay, the first data processing module 9 and the second data processing module 10 extract the first characteristic wave and the second characteristic wave on the DC feeder. The third data processing module 14 extracts the first characteristic wave and the second characteristic wave flowing through the subway vehicle. It is confirmed by calculation and comparison whether a fault has occurred. If it is confirmed that there is no fault, the protection returns and stops the injection of the characteristic wave. If it is confirmed that there is a fault, the first protection device 3 and the second protection device 4 are activated to cut off the power supply at both ends. The control center 17 determines the section where the fault occurs by the amplitude of the abnormal first current and the second current, so as to achieve the purpose of reliable protection and rapid maintenance.

[0058] Among them, the principle and basis for determining whether a fault has occurred are specifically as follows: when the DC traction network is operating normally, including the startup process of the subway vehicle, the characteristic wave extracted from the DC feeder is basically consistent with the characteristic wave current amplitude flowing through the subway vehicle. When a short circuit fault occurs in the DC traction network, the short-circuit branch causes the characteristic wave to be shunted and the loop impedance to be reduced, resulting in the characteristic wave current amplitude extracted from the DC feeder being increased compared to normal circumstances, while the characteristic wave current amplitude flowing through the subway vehicle will decrease and approach zero. At this time, the characteristic wave extracted from the DC feeder is much larger than the characteristic wave current amplitude flowing through the subway vehicle, and this fault characteristic is used as the basis for determining whether a fault has occurred.

[0059] Although the present invention has been disclosed as above in terms of preferred embodiments, it is not intended to limit the present invention. Anyone familiar with the technology may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A DC traction network differential protection system, characterized in that: The differential protection system comprises: a first protection device (3), a first characteristic wave injection device (5), a first current detector (7), a first data processing module (9), a second protection device (4), a second characteristic wave injection device (6), a second current detector (8), a second data processing module (10), a third current detector (13) and a third data processing module (14); The first protection device (3), the first characteristic wave injection device (5), and the first current detector (7) are connected in series on the first DC feeder (19); the first protection device (3) and the first characteristic wave injection device (5) are respectively connected to the first wireless communication module (11); and the first current detector (7) is connected to the first wireless communication module (11) via the first data processing module (9); The second protection device (4), the second characteristic wave injection device (6), and the second current detector (8) are connected in series on the second DC feeder (20); the second protection device (4) and the second characteristic wave injection device (6) are respectively connected to the second wireless communication module (12); and the second current detector (8) is connected to the second wireless communication module (12) via the second data processing module (10); The third current detector (13) and the vehicle electrical equipment (16) are installed in series in the subway vehicle, and the third current detector (13) is connected to the third wireless communication module (15) via the third data processing module (14); The first wireless communication module (11), the second wireless communication module (12), and the third wireless communication module (15) are in communication connection with a subway operation control center (17).

2. The DC traction network differential protection system according to claim 1, characterized in that: The first wireless communication module (11), the second wireless communication module (12), and the third wireless communication module (15) are 5G communication modules.

3. The DC traction network differential protection system according to claim 1, characterized in that: The first protection device (3) and the second protection device (4) are differential protection devices.

4. The DC traction network differential protection system according to claim 1, characterized in that: The first data processing module (9), the second data processing module (10) and the third data processing module (14) are microprocessors.

5. The DC traction network differential protection system according to claim 1, characterized in that: The first characteristic wave injection device (5) and the second characteristic wave injection device (6) are power electronic converters.

6. The DC traction network differential protection system according to claim 1, characterized in that: The installation position sequence of the first protection device (3), the first characteristic wave injection device (5), and the first current detector (7) on the first DC feeder (19) is consistent with the power supply direction of the first DC traction network.

7. The DC traction network differential protection system according to claim 1, characterized in that: The installation position sequence of the second protection device (4), the second characteristic wave injection device (6), and the second current detector (8) on the second DC feeder (20) is consistent with the power supply direction of the second DC traction network.

8. A bilateral traction network power supply system for powering subway vehicles, characterized in that: The power supply system comprises: a first traction substation (1), a second traction substation (2) and a DC traction network; The DC traction network comprises: a first DC feeder (19), a second DC feeder (20), a contact network (21), a running rail (22), a first return line (23), and a second return line (24); The first traction substation (1) is connected to the overhead contact network (21) via the first DC feeder (19); the second traction substation (2) is connected to the overhead contact network (21) via the second DC feeder (20); the overhead contact network (21) is connected to a subway vehicle (18); the subway vehicle (18) is connected to the running rail (22); the running rail (22) is connected to the first traction substation (1) and the second traction substation (2) via the first return line (23) and the second return line (24), respectively; The first DC feeder (19) is sequentially connected in series with a first protection device (3), a first characteristic wave injection device (5), and a first current detector (7); the first protection device (3) and the first characteristic wave injection device (5) are respectively connected to a first wireless communication module (11); and the first current detector (7) is connected to the first wireless communication module (11) via a first data processing module (9); The second DC feeder (20) is sequentially connected in series with a second protection device (4), a second characteristic wave injection device (6), and a second current detector (8); the second protection device (4) and the second characteristic wave injection device (6) are respectively connected to a second wireless communication module (12); and the second current detector (8) is connected to the second wireless communication module (12) via a second data processing module (10); A third current detector (13) and a vehicle electrical device (16) are connected in series in the subway vehicle (18); the third current detector (13) is connected to a third wireless communication module (15) via a third data processing module (14); The first wireless communication module (11), the second wireless communication module (12), and the third wireless communication module (15) are in communication connection with a subway operation control center (17).

9. The bilateral traction network power supply system for powering subway vehicles according to claim 8, characterized in that: The first wireless communication module (11), the second wireless communication module (12), and the third wireless communication module (15) are 5G communication modules.

10. The bilateral traction network power supply system for powering subway vehicles according to claim 8, characterized in that: The first traction substation (1) and the second traction substation (2) convert 35kV alternating current into 1500V direct current for use in subway vehicles.

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