Grounding system for improving electromagnetic compatibility of alternating-current transmission internal combustion locomotive

Abstract

A grounding system for improving the electromagnetic compatibility of an alternating-current transmission internal combustion locomotive, comprising: a traction converter cabinet and a frame connected thereto by means of grounding wires; the frame comprises two bogies, each bogie comprising a framework and traction motors connected to the framework by means of grounding wires, and the two bogies being connected by means of grounding wires; the frame is connected to steel rails by means of a bearing axle box in each bogie; the traction motors in each bogie are used for driving left and right wheel sets to rotate, the left and right wheel sets running on the left and right side steel rails in contact therewith respectively. By reasonably setting grounding points, the system can reduce return currents between bogies and steel rails, such that the distribution of return currents is uniform, thus reducing electromagnetic interference, improving the electromagnetic compatibility of locomotives, and achieving safety and reliability.

Description

A grounding system for improving the electromagnetic compatibility performance of AC transmission diesel locomotives Technical Field

[0001] The present invention relates to the field of rail transportation technology, and in particular to a grounding system for improving the electromagnetic compatibility performance of an AC transmission diesel locomotive. Background Art

[0002] With the rapid development of my country's rail transit and the increasing adoption of AC locomotives, demand for AC locomotives is growing worldwide. Due to their unique characteristics, AC locomotives are poised to gain global favor. Exports to developed countries are also expected to increase. These countries, in turn, place higher demands on the electromagnetic compatibility (EMC) of rail transit vehicles. In some developed countries, track lines are particularly historic, and some outdated track circuit equipment is highly susceptible to electromagnetic interference from locomotives. Consequently, these countries have extremely high requirements for rail signal compatibility. For example, Australia's permitted track current is only about one-third of domestic and European standards. AC locomotives, being complex systems integrating mechanical, power electronics, and electrical equipment, are particularly challenging to meet the EMC requirements of developed countries. Therefore, a suitable locomotive grounding system can help minimize locomotive interference with track signals.

[0003] A locomotive's grounding system must not only protect personnel and equipment from high voltage damage during fault conditions, but also protect locomotive equipment from external interference and trackside signaling equipment from interference from the locomotive's high-frequency or pulsed currents. The grounding system design requires a rational layout and the implementation of effective EMC (electromagnetic compatibility) and EMI (electromagnetic interference) preventive measures to avoid and eliminate mutual electromagnetic interference and ensure a safe and reliable grounding circuit.

[0004] The grounding of AC diesel locomotives generally includes protective grounding and electromagnetic compatibility grounding.

[0005] Protective grounding: Electrical equipment on rail transit vehicles can experience leakage between live wires / components and their housings due to insulation aging, wear, water immersion, or moisture. Leakage can also occur due to severe heat generation and insulation burnout caused by overloaded equipment. Environmental pollution and dust accumulation can also cause leakage or arcing, leading to sparks. Therefore, protective grounding is essential for all electrical equipment on rail transit vehicles. Protective grounding typically connects the equipment housing directly to the vehicle body, then connects to a predetermined protective grounding point via a grounding wire connected to the vehicle body, and then to the rails.

[0006] Electromagnetic compatibility grounding: Internal interference sources on locomotives mainly include various types of converters, motors, switchgear, and radio communication equipment. Dedicated grounding wires are generally used to reliably ground the equipment casings. Locomotive sensitive equipment mainly includes microcomputers, various controllers, and ICE equipment. In addition to being kept as far away from interference sources as possible, sensitive equipment can also be placed in shielded cabinets, and the cabinet casings and chassis must be reliably grounded. At the same time, dedicated grounding wires are installed along the locomotive frame, bogie frame, axle end cap, and traction motor-bogie frame. The entire vehicle is grounded through the wheelset, and the electrical equipment within the locomotive is ultimately connected to the rail surface via low-impedance grounding wires. This eliminates the discharge of high-frequency interference sources and the electrostatic discharge of electronic and electrical equipment, thereby protecting the equipment from electromagnetic interference.

[0007] If a grounding system uses only a single point of grounding, a loose connection or disconnection at that point will cause the locomotive grounding to fail. Therefore, the entire vehicle should generally have at least two grounding points. Multi-point grounding, due to its multiple grounding points, disperses the current from the vehicle body to the bearings, reducing electrical corrosion of the bearings. However, it can also cause uneven current distribution, forming an electrical loop and requiring higher electromagnetic compatibility requirements.

[0008] Summary of the Invention

[0009] In response to the shortcomings of multi-point grounding in the existing technology, such as easy formation of electrical loops and uneven current distribution, the present invention proposes a grounding system that improves the electromagnetic compatibility performance of AC transmission diesel locomotives. By reasonably setting the grounding points, the backflow between the bogie and the rails is reduced, and the return current distribution is more uniform, thereby reducing electromagnetic interference and improving the electromagnetic compatibility of the locomotive.

[0010] The present invention discloses a grounding system for improving the electromagnetic compatibility performance of an AC transmission diesel locomotive, comprising: a traction converter cabinet and a frame connected thereto via a grounding wire; the frame comprising two bogies; each bogie comprising a frame and a traction motor respectively connected to the frame via a grounding wire; the two bogies are connected via a grounding wire; the frame is connected to a rail via a bearing axle box in each bogie;

[0011] The traction motor in each bogie is used to drive the left and right wheels to rotate; the left and right wheels run on the left and right rails in contact with them respectively.

[0012] Furthermore, two resistors are connected in series between the positive and negative poles in the traction converter cabinet, and the two resistors are grounded; one end of the filter capacitor in the traction converter cabinet is connected to the positive pole and the other end is grounded; the traction circuit cabinet is connected to the frame through two grounding ends.

[0013] Furthermore, each bogie includes multiple traction motors, and the traction motors of all bogies are arranged in sequence. Two adjacent traction motors from different bogies are connected through a grounding point on the frame.

[0014] Furthermore, each traction motor is connected to a grounding point on one side of the adjacent frame via a grounding wire.

[0015] Furthermore, the grounding points on one side of each frame in each bogie are connected in sequence, and then connected to the grounding point on the frame through the grounding points symmetrically arranged on the other two sides of the frame.

[0016] Furthermore, a bearing axle box is symmetrically arranged on one side of each bogie, and each bearing axle box is connected to a grounding point on the frame; each bearing axle box is connected to a wheelset through a bearing; and the wheelset is located on the rails.

[0017] Furthermore, the left and right wheel pairs in each bogie are respectively connected to the frame via grounding wires.

[0018] Due to the adoption of the above technical solution, the present invention has the following advantages: by reasonably setting the grounding point, the backflow between the bogie and the rail is reduced, and the backflow current is distributed more evenly, thereby reducing electromagnetic interference and improving the electromagnetic compatibility of the locomotive. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments described in the embodiments of the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0020] FIG1 is a schematic diagram of a grounding system for improving the electromagnetic compatibility performance of an AC transmission diesel locomotive according to an embodiment of the present invention;

[0021] FIG2 is a schematic diagram of a traction converter cabinet intermediate circuit provided with a grounding capacitor according to an embodiment of the present invention;

[0022] FIG3 is a schematic diagram of a locomotive running gear grounding wire according to an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The present invention will be further described with reference to the accompanying drawings and embodiments. Obviously, the embodiments described are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those skilled in the art should fall within the scope of protection of the embodiments of the present invention.

[0024] The present invention provides an embodiment of a grounding system for improving the electromagnetic compatibility performance of an AC transmission diesel locomotive, comprising: a traction converter cabinet and a frame connected thereto via a grounding wire; the frame comprising two bogies; each bogie comprising a frame and a traction motor respectively connected to the frame via a grounding wire; the two bogies are connected via a grounding wire; the frame is connected to a rail via a bearing axle box in each bogie;

[0025] The traction motor in each bogie is used to drive the left and right wheels to rotate; the left and right wheels run on the left and right rails in contact with them respectively.

[0026] In this embodiment, two resistors are connected in series between the positive and negative poles in the traction converter cabinet, and the two resistors are grounded; one end of the filter capacitor in the traction converter cabinet is connected to the positive pole and the other end is grounded; the traction circuit cabinet is connected to the vehicle frame through two grounding terminals.

[0027] In this embodiment, each bogie includes multiple traction motors, and the traction motors of all bogies are arranged in sequence. Two adjacent traction motors from different bogies are connected through a grounding point on the frame.

[0028] In this embodiment, each traction motor is connected to a grounding point on one side of the adjacent frame via a grounding wire.

[0029] In this embodiment, the grounding points on one side of each frame in each bogie are connected in sequence, and then connected to the grounding points on the vehicle frame through the grounding points symmetrically arranged on the other two sides of the frame.

[0030] In this embodiment, axle boxes are symmetrically arranged on one side of each bogie, and each axle box is connected to a grounding point on the frame; each axle box is connected to a wheelset through a bearing; and the wheelset is located on the rails.

[0031] In this embodiment, the left and right wheelsets in each bogie are respectively connected to the frame via grounding wires.

[0032] Specifically, referring to FIG1 , a vehicle is provided with a traction converter cabinet, two bogies, and six traction motors. The traction converter cabinet is connected to the frame ground through an intermediate DC circuit capacitor, and then connected to the rails through the bearing axle box of the corresponding bogie. According to the traction motors, the traction motors at positions 3 and 4 are both grounded to the frame through sequence number (8) on both sides and then connected to the rails through sequence number (7). The traction motors at positions 1 to 3 are connected to the frame through sequence number (5) and the traction motor grounding points are connected in series through sequence number (6), and then concentratedly grounded to the frame through sequence number (9), and then connected to the bogie frame and the rails through sequence number (7). Among them, serial numbers (1) to (9) are: (1) main transformer cabinet, (2) bearing axle box, (3) traction motor, (4) grounding wire between main transformer cabinet and frame, (5) grounding wire between traction motor and frame, (6) grounding wire between bogie frame motor grounding point, (7) grounding wire between bogie frame and bearing axle box, (8) grounding wire between bogie frame and frame, (9) grounding wire between bogie frame motor grounding point and frame for connecting to frame grounding point.

[0033] Referring to Figure 2, VH1A represents a voltage sensor, which is used to measure the half voltage of the half intermediate DC circuit. By comparing it with the full voltage, it can be determined whether the intermediate DC circuit is grounded.

[0034] Because the current generated by the output harmonics of the main converter ultimately needs to flow through the locomotive wheelsets to the rails, the main transmission system grounding solution of the present invention reduces the voltage difference between the wheelsets and the voltage difference between the two rails by optimizing the wiring method of the locomotive grounding wire, thereby greatly reducing the current flowing from the locomotive to the rails, thereby reducing interference with the track circuit.

[0035] This embodiment differs from the grounding of the main transmission system of a conventional internal combustion AC transmission locomotive in the following ways:

[0036] A grounding filter capacitor is added to the intermediate DC circuit of the traction converter cabinet to guide the common-mode current on the motor side back to the inside of the traction converter, thereby reducing the current flowing to the track. Experiments have verified that adding the grounding capacitor has a certain effect on reducing the track current. The schematic diagram is shown in Figure 2.

[0037] Traditional locomotives use a single-side grounding system for each traction motor and single-side grounding between the bogie and wheelset. To reduce the voltage difference between the wheelset and the rail, this embodiment uses a single-point grounding system for the six traction motors and double-side grounding from the bogie to the wheelset. This has been proven to effectively reduce current harmonics by 10%-30%. A schematic diagram of the locomotive running gear grounding system is shown in Figure 3.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A grounding system for improving the electromagnetic compatibility performance of an AC transmission diesel locomotive, characterized in that: include: Traction converter cabinet and the frame connected to it through the grounding wire; Frame It includes two bogies; each bogie includes a frame and a traction motor respectively connected to the frame through a grounding wire; the two bogies are connected through a grounding wire; the frame is connected to the rail through a bearing axle box in each bogie; The traction motor in each bogie is used to drive the left and right wheel pairs to rotate; the left and right wheel pairs run on the left and right side rails in contact with them respectively.

2. The grounding system for improving the electromagnetic compatibility performance of AC transmission diesel locomotive according to claim 1 is characterized in that: Two resistors are connected in series between the positive and negative poles in the traction converter cabinet, and the two resistors are grounded; one end of the filter capacitor in the traction converter cabinet is connected to the positive pole, and the other end is grounded; the traction circuit cabinet is connected to the frame through two grounding terminals.

3. The grounding system for improving the electromagnetic compatibility performance of AC transmission diesel locomotive according to claim 1 is characterized in that: Each bogie includes a plurality of traction motors, and the traction motors of all the bogies are arranged in sequence. Two adjacent traction motors from different bogies are connected via a grounding point on the frame.

4. The grounding system for improving the electromagnetic compatibility of AC transmission diesel locomotive according to claim 1, characterized in that: Each traction motor is connected to a ground point on the side of the frame adjacent to it through a ground wire.

5. The grounding system for improving the electromagnetic compatibility performance of AC transmission diesel locomotive according to claim 1, characterized in that: After the grounding points on one side of each frame in each bogie are connected in sequence, they are connected to the grounding points on the frame through the grounding points symmetrically arranged on the other two sides of the frame.

6. The grounding system for improving the electromagnetic compatibility of AC transmission diesel locomotive according to claim 1, characterized in that: A bearing axle box is symmetrically arranged on one side of each bogie, and each bearing axle box is connected to a grounding point on the frame; each bearing axle box is connected to a wheel set through a bearing; and the wheel set is located on the rail.

7. The grounding system for improving the electromagnetic compatibility of AC transmission diesel locomotive according to claim 1, characterized in that: The left and right wheel pairs in each bogie are connected to the frame through grounding wires respectively.

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