A unipolar short-circuit fault monitoring device and its monitoring method

Abstract

The present application provides a single-pole short-circuit fault monitoring device and a monitoring method thereof. The single-pole short-circuit fault monitoring device includes a current acquisition unit and a single-pole short-circuit fault monitoring unit. The current acquisition unit is configured on the grounding device of the locomotive, connected in series between the car body of the locomotive and the grounding electrode, and acquires the grounding current between the car body of the locomotive and the grounding electrode. The single-pole short-circuit fault monitoring unit is connected to the current acquisition unit, and obtains in real time the grounding current between the car body of the locomotive and the grounding electrode from the current acquisition unit. When the amplitude of the grounding current is greater than the grounding current threshold and the grounding current flows from the car body of the locomotive to the grounding electrode, it is determined that the locomotive has a single-pole short-circuit fault.

Description

Technical Field

[0001] This application relates to the technical fields of subway vehicles and rail transit, and particularly to a single-pole short-circuit fault monitoring device and its monitoring method. Background Art

[0002] The urban rail transit power traction network provides kinetic energy for subway vehicles and consists of an overhead contact line (positive pole) and a return network (negative pole). Currently, most domestic subway traction power supply systems use the running rail as the return network, and the traction current of the locomotive flows back to the traction substation through the running rail. In this power supply method with the running rail as the return network, the traction return current will enter the ballast through the rail to form stray current, which will corrode the rail, the steel bars of the integral ballast structure, the steel bars of the tunnel structure, the steel bars of the bridge, and the metal equipment along the subway line, affecting the service life of various building structures and metal equipment along the subway line.

[0003] To inhibit the influence of stray current corrosion, traditional treatment methods usually adopt various means such as increasing the insulation between the rail and the ground and setting up a stray current collection network, but they cannot fundamentally solve the corrosion problem caused by stray current. As the operation years of the subway increase, due to humidity, metal dust (brake shoe braking), and the heavy pressure of the vehicle body, the insulation impedance between the rail and the ground gradually decreases, and the proportion of the stray current generated by the vehicle running flowing into the line increases year by year, and the electrochemical corrosion phenomenon will become more and more serious.

[0004] To fundamentally solve this problem, some urban rail transit power supply systems set up a dedicated "return rail" as the fourth rail for the traction network, which is completely separated from the running rail of the locomotive, completely solving the problem of stray current corrosion protection.

[0005] Although the return network and the running rail of the DC traction power supply system are completely separated, which can effectively solve the problem of stray current corrosion protection, however, when a ground short-circuit fault occurs in the overhead contact line (positive pole), the complete independence of the return rail and the running rail makes the fault current unable to flow to the return network through the ground, and it is difficult to generate a large fault current, and the protection device configured on the feeder switch cannot identify and clear the fault.

[0006] Therefore, for a DC traction power supply system with the return rail and the running rail completely separated, a grounding resistor with a small resistance value is usually configured on the negative bus of the DC traction substation to be connected to the ground to increase the current amplitude generated during the ground short-circuit fault of the overhead contact line (positive pole). However, when a short-circuit fault occurs in the overhead contact line (positive pole) through the locomotive, due to the large resistance value of the locomotive shell, the change in current before and after the fault may be small, and the protection device configured on the feeder switch is still difficult to identify the fault.

[0007] In case of short circuit fault of catenary (positive pole) through locomotive, subway vehicles running on special "return rail" are usually equipped with grounding relays in the vehicle, which are connected between the vehicle body and the negative power receiving shoe. When the catenary (positive pole) discharges to the vehicle body, the potential of the vehicle body rises, which triggers the grounding relay to operate, thereby determining the vehicle fault. However, when the catenary (positive pole) discharges to the vehicle body when the locomotive enters the station, the potential of the grounding equipment installed on the subway vehicle may cause the potential of the station where the faulty vehicle stops and its adjacent stations to rise, which in turn causes the grounding relays of the vehicles parked in the adjacent stations to operate simultaneously, making it difficult for the operation and maintenance personnel to identify the faulty vehicle. Summary of the invention

[0008] An embodiment of the present application provides a single-pole short-circuit fault monitoring device, comprising a current acquisition unit and a single-pole short-circuit fault monitoring unit, wherein the current acquisition unit is arranged on a grounding device of a locomotive, is connected in series between a body of the locomotive and a grounding electrode, and collects a grounding current between the locomotive body and the grounding electrode; the single-pole short-circuit fault monitoring unit is connected to the current acquisition unit, and obtains the grounding current between the locomotive body and the grounding electrode from the current acquisition unit in real time, and when the amplitude of the grounding current is greater than a grounding current threshold and the grounding current flows from the locomotive body to the grounding electrode, it is determined that a single-pole short-circuit fault occurs in the locomotive.

[0009] According to some embodiments, the device further comprises a monitoring unit, which is connected to the single-pole short-circuit fault monitoring unit and is used to receive locomotive abnormality alarm information from the single-pole short-circuit fault monitoring unit.

[0010] According to some embodiments, the ground current threshold is,

[0011]

[0012] Among them, I dire is the grounding current threshold, K is the reliability coefficient, U is the grounding relay protection action voltage of the locomotive, and R is the resistance of the system grounding resistor.

[0013] According to some embodiments, the locomotive obtains DC power through an independent contact network and a return network, the contact network is the positive pole of the DC traction power supply system, the return network is the negative pole of the DC traction power supply system, and the return network is completely independent and insulated from the running rails.

[0014] According to some embodiments, the positive electrode of the current collection unit is close to the body or grounding electrode of the locomotive.

[0015] According to some embodiments, when the grounding current flows from the locomotive body to the grounding electrode, the direction of the grounding current is positive, and when the grounding current flows from the grounding electrode to the locomotive body, the direction of the grounding current is negative.

[0016] The embodiment of the present application also provides a method for monitoring single - pole short - circuit faults, including: acquiring the grounding current between the locomotive body and the grounding electrode in real time; when the amplitude of the grounding current is greater than the grounding current threshold and the grounding current flows from the locomotive body to the grounding electrode, it is determined that the locomotive has a single - pole short - circuit fault.

[0017] According to some embodiments, the method further includes: sending a tripping signal to the on - vehicle circuit breaker.

[0018] According to some embodiments, the method further includes: sending locomotive abnormal alarm information to the monitoring unit.

[0019] According to some embodiments, the grounding current threshold is

[0020] where, I dire is the grounding current threshold, K is the reliability coefficient, U is the operating voltage of the locomotive grounding relay protection, and R is the resistance value of the system grounding resistance.

[0021] In the technical solution provided by the embodiment of the present application, the single - pole short - circuit fault monitoring device identifies the faulty vehicle according to the current direction flowing through the grounding device. It can not only accurately judge the short - circuit fault of the catenary (positive pole) through the locomotive to the ground, but also add the judgment of the grounding current direction, which can effectively eliminate the interference of the station potential rise on the judgment of the faulty vehicle. By setting the grounding current threshold, the single - pole short - circuit fault monitoring unit can avoid misjudgment caused by static electricity, etc., and eliminate the influence of factors such as the transformation error of the current acquisition unit and static electricity discharge on the direction judgment. The single - pole short - circuit fault monitoring unit sends locomotive fault alarm information to the monitoring unit through wireless communication technology, which can provide a basis for the maintenance personnel to quickly view and judge the faulty vehicle, and ensure the normal operation of the subway. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0023] Figure 1 It is a schematic diagram of a locomotive obtaining power from a DC traction power supply system of the present application.

[0024] Figure 2 It is a schematic diagram of the composition of a single - pole short - circuit fault monitoring device of the present application.

[0025] Figure 3It is a schematic diagram of the communication between a single - pole short - circuit fault monitoring unit and a monitoring unit of the present application.

[0026] Figure 4 It is a schematic diagram of the monitoring method flow of a single - pole short - circuit fault monitoring device of the present application.

[0027] Figure 5 It is a schematic diagram of the monitoring method flow of another single - pole short - circuit fault monitoring device of the present application.

[0028] Explanation of the drawing symbols:

[0029] a - Catenary (positive pole), b - Return network (negative pole), c - Positive - pole current collector shoe, d - Negative - pole current collector shoe, e - Grounding device, f - Current acquisition unit, g - On - vehicle circuit breaker, h - Vehicle A, i - Grounding electrode, j - Earth, k - Vehicle B, R - System grounding resistance, m - Single - pole short - circuit fault monitoring device. Detailed implementation manners

[0030] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present application.

[0031] It should be understood that the terms "including" and "comprising" used in the specification and claims of the present application indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0032] Figure 1 It is a schematic diagram of a locomotive obtaining power from a DC traction power supply system of the present application.

[0033] As Figure 1 shown, the locomotive h obtains direct current through the independent catenary a and return network b. The catenary a is the positive pole of the DC traction power supply system, and the return network b is the negative pole of the DC traction power supply system. The return network b is completely independent and insulated from the running rail.

[0034] The traction substation supplies power to the contact network a and the return network b. The high-voltage circuit of locomotive h receives power from the contact network a and the return network b through the positive receiving shoe c and the negative receiving shoe d. The on-board circuit breaker g is connected in series in the high-voltage circuit of locomotive A. The current collection unit f is connected in series to the grounding device e mounted on the body of locomotive h. The grounding electrode i is the grounding terminal of the grounding device e. The current collection unit f includes but is not limited to a through-type current collection unit. The positive pole of the current collection unit f is close to the body or grounding electrode of the locomotive to ensure that when the grounding current flows from the locomotive body to the grounding electrode, the direction of the grounding current is positive, and when the grounding current flows from the grounding electrode to the locomotive body, the direction of the grounding current is negative.

[0035] Figure 2 It is a schematic diagram of the composition of a single-pole short-circuit fault monitoring device of the present application.

[0036] According to some embodiments, the single-pole short-circuit fault monitoring device includes a current acquisition unit f and a single-pole short-circuit fault monitoring unit m, such as Figure 2 shown.

[0037] The current acquisition unit f is configured on the grounding device e of the locomotive, and is connected in series between the body of the locomotive h and the grounding electrode i of the grounding device e, to collect the grounding current between the locomotive body and the grounding electrode. The single-pole short-circuit fault monitoring unit m is connected to the current acquisition unit f, and obtains the grounding current between the locomotive body and the grounding electrode from the current acquisition unit f in real time. When the amplitude of the grounding current is greater than the grounding current threshold and the grounding current flows from the locomotive body to the grounding electrode, it is determined that a single-pole short-circuit fault occurs in the locomotive.

[0038] Optionally, the single-pole short-circuit fault monitoring device further includes a monitoring unit s, such as Figure 3 The monitoring unit s is connected to the single-pole short-circuit fault monitoring unit m, and the connection method includes but is not limited to wireless connection. The monitoring unit s is used to receive the locomotive abnormality alarm information from the single-pole short-circuit fault monitoring unit m, so as to detect the locomotive abnormality in time and ensure safe operation.

[0039] like Figure 1 As shown in the figure, when a fault occurs at point K1, the current acquisition unit f collects the grounding current flowing through the grounding device, and the single-pole short-circuit fault monitoring unit m configured on the locomotive h receives the grounding current. When the grounding current is greater than the grounding current threshold I dire , start ground current direction judgment.

[0040] The ground current threshold is,

[0041] Among them, I dire is the grounding current threshold, K is the reliability coefficient, U is the protection action voltage of the locomotive grounding relay q, and R is the resistance value of the system grounding resistor.

[0042] When the grounding current flows from the locomotive body to the grounding electrode, the direction of the grounding current is positive; when the grounding current flows from the grounding electrode to the locomotive body, the direction of the grounding current is negative.

[0043] When it is detected that the direction of the grounding current is the positive direction, the single-pole short-circuit fault monitoring unit determines that the locomotive h has a short-circuit fault through the locomotive from the catenary (positive pole), sends a tripping signal to the on-vehicle circuit breaker, and sends a vehicle fault alarm signal to the monitoring unit.

[0044] When it is detected that the direction of the grounding current is the negative direction, the single-pole short-circuit fault monitoring unit determines that the locomotive h has a short-circuit fault through the locomotive from the catenary (positive pole), sends a tripping signal to the on-vehicle circuit breaker, and sends a vehicle fault alarm signal to the monitoring unit.

[0045] Optionally, the catenary a and the return network b of the DC traction power supply system can supply power to multiple locomotives simultaneously. As Figure 3 shown, both the locomotive h and the locomotive k draw power from the catenary a and the return network b. Each locomotive is equipped with a current acquisition unit f and a single-pole short-circuit fault monitoring unit m. m and f are connected in one-to-one correspondence to independently judge faults, or multiple locomotives are jointly equipped with a single-pole short-circuit fault monitoring unit m, and each locomotive is equipped with a current acquisition unit f. m and f form a one-to-many connection.

[0046] Figure 4 It is a schematic diagram of the monitoring method flow of a single-pole short-circuit fault monitoring device of the present application, including the following processes.

[0047] In S10, the grounding current between the locomotive body and the grounding electrode is obtained in real time.

[0048] In S20, when the amplitude of the grounding current is greater than the grounding current threshold and the grounding current flows from the locomotive body to the grounding electrode, it is determined that the locomotive has a single-pole short-circuit fault.

[0049] The grounding current threshold is

[0050] where, I dire is the grounding current threshold, K is the reliability coefficient, U is the operating voltage of the grounding relay protection of the locomotive, and R is the resistance value of the system grounding resistance.

[0051] Figure 5 It is a schematic diagram of the monitoring method flow of another single-pole short-circuit fault monitoring device of the present application, including the following processes.

[0052] In S10, the grounding current between the locomotive body and the grounding electrode is obtained in real time.

[0053] In S20, when the amplitude of the grounding current is greater than the grounding current threshold and the grounding current flows from the locomotive body to the grounding electrode, it is determined that a single-pole short-circuit fault occurs in the locomotive.

[0054] The grounding current threshold is where I dire is the grounding current threshold, K is the reliability coefficient, U is the operating voltage of the grounding relay protection of the locomotive, and R is the resistance value of the system grounding resistance.

[0055] In S30, a trip signal is sent to the on-vehicle circuit breaker, and an abnormal alarm message of the locomotive is sent to the monitoring unit.

[0056] The above embodiments are only used to illustrate the technical idea of the present application, and the protection scope of the present application cannot be limited thereby. Any modification made on the basis of the technical solution according to the technical idea proposed in the present application falls within the protection scope of the present application.

Claims

1. A single - pole short - circuit fault monitoring device, comprising: A current acquisition unit, configured on the grounding device of the locomotive, connected in series between the car body of the locomotive and the grounding electrode, and acquiring the grounding current between the car body of the locomotive and the grounding electrode; A single - pole short - circuit fault monitoring unit, connected to the current acquisition unit, and acquiring in real time the grounding current between the car body of the locomotive and the grounding electrode from the current acquisition unit. When the amplitude of the grounding current is greater than the grounding current threshold and the grounding current flows from the car body of the locomotive to the grounding electrode, it is determined that the locomotive has a single - pole short - circuit fault; when the amplitude of the grounding current is greater than the grounding current threshold and the grounding current flows from the grounding electrode to the car body of the locomotive, it is determined that the locomotive is normal.

2. The device according to claim 1, further comprising: A monitoring unit, connected to the single - pole short - circuit fault monitoring unit, and used for receiving the locomotive abnormal alarm information from the single - pole short - circuit fault monitoring unit.

3. The device according to claim 1, wherein The grounding current threshold is Among them, I dire is the ground current threshold, K is the reliability coefficient, U is the operating voltage of the ground relay protection of the locomotive, and R is the resistance value of the system ground resistance.

4. The device according to claim 1, wherein, The locomotive obtains direct current through an independent catenary and return network. The catenary is the positive pole of the DC traction power supply system, and the return network is the negative pole of the DC traction power supply system. The return network is completely independent and insulated from the running rails.

5. The device according to claim 1, wherein, The positive pole of the current acquisition unit is close to the car body or the grounding electrode of the locomotive.

6. The device according to claim 1, wherein When the grounding current flows from the car body of the locomotive to the grounding electrode, the direction of the grounding current is positive; when the grounding current flows from the grounding electrode to the car body of the locomotive, the direction of the grounding current is negative.

7. A single - pole short - circuit fault monitoring method, comprising: Acquiring in real time the grounding current between the car body of the locomotive and the grounding electrode; When the amplitude of the grounding current is greater than the grounding current threshold and the grounding current flows from the car body of the locomotive to the grounding electrode, determining that the locomotive has a single - pole short - circuit fault; When the amplitude of the grounding current is greater than the grounding current threshold and the grounding current flows from the grounding electrode to the car body of the locomotive, determining that the locomotive is normal.

8. The method according to claim 7, further comprising: Sending a tripping signal to the on - vehicle circuit breaker.

9. The method according to claim 7, further comprising: Sending the locomotive abnormal alarm information to the monitoring unit.

10. The method according to claim 7, wherein, The grounding current threshold is Among them, I dire is the ground current threshold, K is the reliability coefficient, U is the operating voltage of the ground relay protection of the locomotive, and R is the resistance value of the system ground resistance.

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