Grounding system for improving electromagnetic compatibility of AC drive diesel locomotive

Abstract

The application discloses a grounding system for improving electromagnetic compatibility of an AC transmission diesel locomotive, which comprises a traction converter cabinet and a frame connected with the traction converter cabinet through grounding wires; the frame comprises two bogies; each bogie comprises a framework and a traction motor connected with the framework through grounding wires; the two bogies are connected through grounding wires; the frame is connected with a steel rail through a bearing axle box in each bogie; the traction motor in each bogie is used for driving left and right wheel pairs to rotate; the left and right wheel pairs run on left and right side steel rails in contact with the left and right wheel pairs respectively. The application can reduce backflow between the bogies and the steel rails by reasonably arranging grounding points, the backflow current is distributed more uniformly, electromagnetic interference is reduced, electromagnetic compatibility of the locomotive is improved, and the locomotive is safe and reliable.

Description

Technical Field

[0001] This invention relates to the technical field of rail transit, and in particular to a grounding system for improving the electromagnetic compatibility performance of AC drive diesel locomotives. Background Technology

[0002] With the rapid development of my country's rail transit and the increasing adoption of AC drive in diesel locomotives, the global demand for AC drive locomotives is constantly growing. Due to their unique characteristics, AC drive diesel locomotives are bound to be favored by countries worldwide. Simultaneously, the export of locomotives to developed countries will also increase. However, these developed countries are placing higher demands on the electromagnetic compatibility (EMC) of rail transit vehicles. In particular, some developed countries have long-established rail lines and outdated track circuit equipment, making them highly susceptible to electromagnetic interference from locomotives. Therefore, their track signal compatibility requirements are extremely high. For example, Australia allows track current levels that are almost only one-third of the levels permitted by domestic and European standards. AC drive diesel locomotives are complex systems integrating mechanical, power electronic, and electrical equipment, making it very difficult to meet the EMC requirements of developed countries' rail transit systems. A suitable locomotive grounding system can help reduce locomotive interference with track signals.

[0003] The locomotive's grounding system must not only protect personnel and equipment from high voltage during fault conditions, but also prevent external interference to locomotive equipment and interference from high-frequency or pulse currents from the locomotive to trackside signaling equipment. The grounding system design requires a reasonable layout and the adoption of effective EMC (electromagnetic compatibility) and EMI (electromagnetic interference) prevention measures to avoid and eliminate mutual electromagnetic interference, ensuring the safety and reliability of the grounding circuit.

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

[0005] Protective grounding: During use, electrical equipment on rail transit vehicles may experience leakage between live wires / components and the vehicle casing due to insulation aging, wear, water immersion, or dampness. Overloading can also cause severe overheating and insulation burn-out, leading to leakage. Environmental pollution and dust accumulation can also cause leakage or arcing. Therefore, protective grounding is essential for all electrical equipment on rail transit vehicles. Protective grounding typically involves directly connecting the equipment casing to the vehicle body, then connecting a grounding wire to the vehicle body to a predetermined protective grounding point, and finally to the rails.

[0006] Electromagnetic compatibility grounding: Internal interference sources in the locomotive mainly include various converters, motors, switching devices, and radio communication equipment. Dedicated grounding wires are generally used to reliably ground the equipment casings. Sensitive equipment in the locomotive mainly includes microcomputers, various controllers, and ICE (Integrated Circuit Interference Equipment). Besides being kept as far away from interference sources as possible, sensitive equipment can also be placed in shielded cabinets, with reliable grounding of the cabinet casing and chassis. Simultaneously, the locomotive frame-bogie frame-axle end caps and traction motor-bogie frame are equipped with dedicated grounding wires, achieving full vehicle grounding via the wheelsets. This connects the electrical equipment inside the locomotive to the rail surface through low-impedance grounding wires, eliminating discharge from high-frequency interference sources and electrostatic discharge from electronic and electrical equipment, thereby preventing electromagnetic interference.

[0007] If the grounding system uses only a single-point grounding, and that point is not properly connected or is disconnected, the locomotive's grounding will fail. Therefore, the entire vehicle generally has no fewer than two grounding points. Multiple grounding points disperse the current from the car body to the bearings, reducing bearing electro-corrosion. However, this can also lead to uneven current distribution, creating electrical circuits and requiring higher electromagnetic compatibility. Summary of the Invention

[0008] To address the shortcomings of existing technologies such as the potential for forming electrical loops and uneven current distribution due to multiple grounding points, this invention proposes a grounding system that improves the electromagnetic compatibility performance of AC drive diesel locomotives. By rationally setting grounding points, the return current between the bogie and the rail is reduced, and the return current distribution is made more uniform, thereby reducing electromagnetic interference and improving the locomotive's electromagnetic compatibility.

[0009] This invention discloses a grounding system for improving the electromagnetic compatibility performance of AC drive diesel locomotives, comprising: a traction converter cabinet and a frame connected thereto via a grounding wire; the frame includes two bogies; each bogie includes a frame and a traction motor connected to the frame via a grounding wire; the two bogies are connected to each other via a grounding wire; the frame is connected to the rails via bearing axle boxes in each bogie.

[0010] The traction motor in each bogie drives the left and right wheelsets to rotate; the left and right wheelsets run on the left and right rails that are in contact with them, respectively.

[0011] Furthermore, in the traction converter cabinet, two resistors are connected in series between the positive and negative terminals, and the two resistors are grounded; one end of the filter capacitor in the traction converter cabinet is connected to the positive terminal, and the other end is grounded; the traction circuit cabinet is connected to the vehicle frame through two grounding terminals.

[0012] 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 grounding points on the frame.

[0013] Furthermore, each traction motor is connected to a grounding point on the adjacent side of the frame via a grounding wire.

[0014] Furthermore, after the grounding points on one side of each bogie are connected in sequence, they are connected to the grounding points on the vehicle frame through grounding points symmetrically arranged on the other two sides of the bogie.

[0015] Furthermore, each bogie has a bearing axle box symmetrically arranged on one side, and each bearing axle box is connected to a grounding point on the frame; each bearing axle box is connected to the wheelset through a bearing; the wheelset is located on the rail.

[0016] Furthermore, the left and right wheelsets in each bogie are connected to the frame via grounding wires.

[0017] Due to the adoption of the above technical solution, the present invention has the following advantages: by reasonably setting the grounding point, the return current between the bogie and the rail is reduced, and the return current distribution is made more uniform, thereby reducing electromagnetic interference and improving the electromagnetic compatibility of the locomotive. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments recorded in the embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0019] Figure 1 This is a schematic diagram of a grounding system for improving the electromagnetic compatibility performance of an AC-drive diesel locomotive, according to an embodiment of the present invention.

[0020] Figure 2 A schematic diagram of a grounding capacitor installed in the intermediate circuit of the traction converter cabinet according to an embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of the grounding wire of the locomotive running gear according to an embodiment of the present invention. Detailed Implementation

[0022] The present invention will be further described in conjunction with the accompanying drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art should fall within the protection scope of the present invention.

[0023] This invention provides an embodiment of a grounding system for improving the electromagnetic compatibility performance of an AC-drive diesel locomotive, comprising: a traction converter cabinet and a frame connected thereto via a grounding wire; the frame includes two bogies; each bogie includes a frame and a traction motor connected to the frame via a grounding wire; the two bogies are connected to each other via a grounding wire; the frame is connected to the rails via bearing axle boxes in each bogie.

[0024] The traction motor in each bogie drives the left and right wheelsets to rotate; the left and right wheelsets run on the left and right rails that are in contact with them, respectively.

[0025] In this embodiment, two resistors are connected in series between the positive and negative terminals 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 terminal, and the other end is grounded; the traction circuit cabinet is connected to the vehicle frame through two grounding terminals.

[0026] 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 grounding points on the frame.

[0027] In this embodiment, each traction motor is connected to a grounding point on the adjacent side of the frame via a grounding wire.

[0028] In this embodiment, after the grounding points on one side of each bogie are connected in sequence, they are connected to the grounding points on the vehicle frame through grounding points symmetrically arranged on the other two sides of the bogie.

[0029] In this embodiment, bearing axle boxes are 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 the wheelset through a bearing; the wheelset is located on the rail.

[0030] In this embodiment, the left and right wheelsets in each bogie are connected to the frame via grounding wires.

[0031] Specifically, see Figure 1The vehicle is equipped with one traction converter cabinet, two bogies, and six traction motors. The traction converter cabinet is connected to the frame ground through the intermediate DC circuit capacitor, and then connected to the rail through the bearing axle box of the corresponding bogie. The traction motors are numbered sequentially. The traction motors located at the 3rd and 4th positions are grounded to the frame through serial number (8) and then connected to the rail through serial number (7). The traction motors at the 1st to 3rd positions are connected to the frame through serial number (5) and the grounding points of the traction motors are connected in series through serial number (6) and then connected to the frame through serial number (9). The bogie frame is then connected to the rail through serial number (7). Among them, serial numbers (1) to (9) are respectively: (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 used to connect frame grounding point.

[0032] See Figure 2 VH1A represents a voltage sensor used to measure the half voltage of the intermediate DC circuit. By comparing it with the full voltage, it can be determined whether the intermediate DC circuit is grounded.

[0033] Since the current generated by the harmonics output by the main converter must eventually flow to the rails through the locomotive wheelsets, the grounding scheme of the main drive system of this 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, which greatly reduces the current flowing from the locomotive to the rails, thereby reducing interference to the track circuit.

[0034] This embodiment differs from the grounding of the main drive system in a traditional internal combustion AC transmission locomotive in the following ways:

[0035] A grounding filter capacitor is added to the intermediate DC circuit of the traction converter cabinet to guide the common-mode current from the motor side back to 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 track current. The schematic diagram is shown below. Figure 2 As shown.

[0036] Traditional locomotives use individual grounding for each traction motor and single-sided grounding between the bogie and wheelsets. This embodiment, to reduce the voltage difference between the wheelsets and rails, centralizes the grounding wires of the six traction motors through a single grounding point and changes the grounding from the bogie to the wheelsets to double-sided grounding. Verification has shown that this effectively reduces current harmonic content by 10%-30%. A schematic diagram of the locomotive running gear grounding wires is shown below. Figure 3 As shown.

[0037] 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, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A grounding system for improving the electromagnetic compatibility performance of AC drive diesel locomotives, characterized in that, include: Traction converter cabinet and the chassis connected to it via a grounding wire; frame It includes two bogies; each bogie includes a frame and a traction motor connected to the frame via a grounding wire; the two bogies are connected by a grounding wire; the frame is connected to the rails through bearing axle boxes in each bogie; The traction motor in each bogie drives the left and right wheelsets to rotate; the left and right wheelsets run on the left and right rails that are in contact with them, respectively. In the traction converter cabinet, two resistors are connected in series between the positive and negative terminals, and the two resistors are grounded; one end of the filter capacitor in the traction converter cabinet is connected to the positive terminal, and the other end is grounded; the traction circuit cabinet is connected to the vehicle frame through two grounding terminals. 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 grounding points on the frame. The left and right wheelsets in each bogie are connected to the frame via grounding wires.

2. The grounding system for improving the electromagnetic compatibility performance of AC drive diesel locomotives according to claim 1, characterized in that, Each traction motor is connected to a grounding point on the side of the adjacent frame via a grounding wire.

3. The grounding system for improving the electromagnetic compatibility performance of AC drive diesel locomotives according to claim 1, characterized in that, After the grounding points on one side of each bogie are connected in sequence, they are connected to the grounding points on the car frame through grounding points symmetrically set on the other two sides of the bogie.

4. The grounding system for improving the electromagnetic compatibility performance of AC drive diesel locomotives according to claim 1, characterized in that, Each bogie has a bearing axle box symmetrically arranged on one side, and each bearing axle box is connected to a grounding point on the frame; each bearing axle box is connected to the wheelset through a bearing; the wheelset is located on the rail.

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