A pantograph cutting magnetic line force working condition vehicle network model modeling method and system

Abstract

The application discloses a pantograph cutting magnetic line working condition vehicle network model modeling method and system, relates to the modeling technical field, and comprises the following steps: based on the self-impedance and ground admittance of a contact wire, the self-impedance and ground admittance of a steel rail and the mutual impedance between the contact wire and the steel rail, a unit length lumped τ type circuit of a traction network is constructed; the unit length lumped τ type circuit is cascaded; a dynamic electromotive force generated when a train runs is taken as an equivalent voltage source, one end of the equivalent voltage source is connected with the contact wire connected with a pantograph in sliding mode in a chain type lumped τ type network model, the other end is connected with a roof end of a train model, a bottom end of the train model is connected with the steel rail, and a vehicle network model under the pantograph cutting magnetic line working condition is obtained. The application provides a vehicle network model modeling method for a high-speed train pantograph cutting magnetic line, and the influence of the pantograph cutting magnetic line on the train and each line of a traction power supply system under different running speeds of the train can be simulated and obtained.

Description

Technical Field

[0001] This invention relates to the field of modeling technology, and in particular to a method and system for modeling a vehicle-grid model under the condition of a pantograph cutting magnetic lines of force. Background Technology

[0002] During operation, electric locomotives obtain electrical energy from contact wires via a pantograph on the roof. The contact wires are typically made of copper or copper alloys, and when energized, a magnetic field is generated around them. As the pantograph slides at high speed against the contact wire, the upper and lower arms of the pantograph cut through the magnetic lines of force, generating a localized induced electromotive force (EMF), primarily a motional EMF. Figure 1 As shown, when the pantograph cuts the magnetic lines of force around the contact wire, eddy currents and additional induced currents may be generated, increasing energy loss and contact point heating, accelerating the wear of the sliding plate and contact wire, and may also lead to uneven current distribution, affecting the stability of the pantograph-catenary contact.

[0003] Currently, electric locomotive catenary models typically model the power supply path from the contact wire to the pantograph, roof busbar, traction converter and traction motor (and other onboard traction equipment), and finally to the rails. This model equates normal train operation by directly connecting the contact wire to the roof busbar via a conductor, and then adds pantograph-catenary disconnection and phase-splitting arcing between the contact wire and roof busbar to represent these conditions. However, existing catenary models neglect the impact of the pantograph cutting magnetic lines of force on the catenary system. Summary of the Invention

[0004] Based on the shortcomings of the existing technology, the present invention provides a vehicle-net modeling method and system for the condition of pantograph cutting magnetic field lines, which solves the problem that the existing vehicle-net models ignore the impact of pantograph cutting magnetic field lines on the vehicle-net system.

[0005] The present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a method for modeling a vehicle-grid model under the condition of a pantograph cutting magnetic field lines, comprising the following steps:

[0007] The first self-impedance and first ground admittance of the traction network contact wire that is slidably connected to the pantograph when the train is running, as well as the self-impedance and ground admittance of the rail where the train is running, are obtained. Based on the self-impedance and ground admittance of the contact wire, the self-impedance and ground admittance of the rail, and the mutual impedance between the contact wire and the rail, a unit length lumped τ-type circuit of the traction network is constructed.

[0008] By cascading unit-length lumped τ-type circuits, a chain-type lumped τ-type network model of the traction network is obtained;

[0009] The motional electromotive force generated during train operation is used as an equivalent voltage source. During the sliding process of the pantograph, the current in the upper and lower arms cutting the contact wire generates magnetic lines of force in the magnetic field, thus generating motional electromotive force.

[0010] One end of the equivalent voltage source is connected to the contact line that is slidably connected to the pantograph in the chain lumped τ-type network model, and the other end is connected to the top of the train model. The bottom of the train model is connected to the rail, thus obtaining the train-network model under the condition of the pantograph cutting magnetic lines of force.

[0011] Preferably, the motional electromotive force is as follows:

[0012] ;

[0013] In the formula, E To generate an electromotive force. n This is the vertical distance between the roof and the contact line. r Where is the radius of the contact line. The permeability of free space, I For the current on the contact wire, L The length of the upper and lower arms of the pantograph that cuts the magnetic field lines. v This refers to the cutting speed.

[0014] Preferably, the train model is constructed based on the equivalent impedance of the train head, the equivalent impedance of the carriages, the equivalent resistance of the grounding resistor, the connection resistance between the carriages, and the equivalent resistance of the grounding carbon brush.

[0015] Preferably, the vehicle network model further includes a traction transformer, the output of which is connected to the contact wire and the rail respectively.

[0016] Secondly, the present invention also provides a vehicle-grid modeling system for the condition of pantograph cutting magnetic field lines, comprising:

[0017] The module is used to obtain the self-impedance and ground admittance of the traction network contact wire that is slidably connected to the pantograph when the train is running, as well as the self-impedance and ground admittance of the rail on which the train is running. Based on the self-impedance and ground admittance of the contact wire, the self-impedance and ground admittance of the rail, and the mutual impedance between the contact wire and the rail, a unit length lumped τ-type circuit of the traction network is constructed.

[0018] The cascade module is used to cascade unit-length lumped τ-type circuits to obtain a chain-type lumped τ-type network model of the traction network;

[0019] The cutting module is used to use the motional electromotive force generated during train operation as an equivalent voltage source. During the sliding process of the pantograph, its upper and lower arms cut the contact wire current to generate magnetic lines of force in the magnetic field, thus generating motional electromotive force.

[0020] The connection module is used to connect one end of the equivalent voltage source to the contact line that is slidably connected to the pantograph in the chain lumped τ-type network model, and the other end to the top of the train model. The bottom end of the train model is connected to the rail, thus obtaining the train-network model under the condition of the pantograph cutting magnetic lines of force.

[0021] Compared with the prior art, the above-mentioned at least one technical solution adopted by the present invention can achieve the following beneficial effects:

[0022] This invention first constructs a unit-length lumped τ-type circuit for the traction network; then, cascades these unit-length lumped τ-type circuits to obtain a chain-like lumped τ-type network model of the traction network. Next, the motional electromotive force generated during train operation is used as an equivalent voltage source. One end of this equivalent voltage source is connected to the contact wire slidingly connected to the pantograph in the chain-like lumped τ-type network model, and the other end is connected to the top of the train model. The bottom of the train model is connected to the rail, resulting in a train-network model under the condition of pantograph cutting magnetic field lines. This invention provides a modeling method for a train-network model of pantograph cutting magnetic field lines in high-speed trains. It can simulate the impact of pantograph cutting magnetic field lines on the train and various lines of the traction power supply system at different train speeds, providing a theoretical basis and technical support for the electromagnetic protection design of electrified railways. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the electromagnetic induction principle of a pantograph.

[0025] Figure 2 This is a schematic diagram of the chain circuit model of the traction power supply system of the present invention;

[0026] Figure 3 This is a schematic diagram of the unit-length lumped τ-type circuit of the present invention;

[0027] Figure 4 This is a schematic diagram of the MTL chain lumped τ-type circuit of the traction network of the present invention;

[0028] Figure 5 This is a schematic diagram of the train model of the present invention;

[0029] Figure 6 This is a schematic diagram of a vehicle-grid model illustrating the pantograph cutting magnetic field lines according to the present invention.

[0030] Figure 7This is a flowchart of a vehicle-grid modeling method for a pantograph cutting magnetic field lines under the present invention. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Based on existing problems, this invention provides a modeling method for a train-grid model of pantograph cutting magnetic field lines in high-speed trains, used to study the impact of pantograph cutting magnetic field lines on various lines of the traction power supply system and the train system at different train operating speeds. (Refer to...) Figure 7 Specifically, it includes the following steps:

[0033] S1: Obtain the self-impedance and ground admittance of the traction network contact wire that is slidably connected to the pantograph when the train is running, as well as the self-impedance and ground admittance of the rail on which the train is located when it is running. Based on the self-impedance and ground admittance of the contact wire, the self-impedance and ground admittance of the rail, and the mutual impedance between the contact wire and the rail, construct a unit length lumped τ-type circuit of the traction network.

[0034] A chain circuit model is used to model the traction power supply system. From an overall perspective, the multiple power supply lines of the traction network conform to the theory of parallel multi-conductor transmission lines, thus forming a composite chain circuit in terms of topology. Other electrical equipment can be considered as parallel and series components distributed along the lines, such as... Figure 2 As shown, the figure contains m There are several routes. Table 1 shows... Figure 2 Series and parallel elements in the circuit.

[0035] Table 1 Series and Parallel Elements

[0036]

[0037] Given the unit length self-impedance, mutual impedance, admittance to ground, and inter-conductor admittance of each line in the traction network, the type and number of lines in the traction network will differ depending on the power supply method. Taking the contact wire and rail lines as examples, we can obtain the following... Figure 3 The diagram shows a unit-length lumped τ-type network model. Here, Z1 is the self-impedance of the contact wire, Z2 is the self-impedance of the rail, M is the mutual impedance between the contact wire and the rail, Y1 is the contact wire's admittance to ground, Y2 is the rail's admittance to ground, and Y3 is the mutual admittance between the contact wire and the rail. In summary, a unit-length lumped τ-type network model of the contact wire and rail can be established.

[0038] S2: Cascade unit-length lumped τ-type circuits to obtain a chain-type lumped τ-type network model of the traction network.

[0039] By cascading the ports of a lumped τ-type network model of unit length, we can obtain... Figure 4 The model shown is a chain-type lumped τ-type network model of the entire traction network (MTL (multi-conductor transmission line) chain circuit model).

[0040] S3: Use the motional electromotive force generated during train operation as an equivalent voltage source.

[0041] According to the right-hand rule, when a conductor moves at a constant velocity cutting magnetic field lines in a uniform magnetic field, the magnitude of the induced electromotive force depends only on the magnetic flux density, regardless of whether the circuit is closed or not. B Length of the upper and lower arms of the pantograph cutting magnetic field lines L Cutting speed v and v and B Angle of direction θ The sine value is proportional to the sine value, satisfying equation (1), and the direction of the electromotive force is the same as the direction of the generated induced current.

[0042] (1);

[0043] The magnetic field of an infinitely long current-carrying straight conductor is shown in equation (2):

[0044] (2);

[0045] in, Let be the vacuum permeability, and take . , I For the current on the contact wire, This represents the distance from the desired location to the conductor.

[0046] Assuming the vertical distance between the roof and the contact line is n , n The distance between the pantograph and the contact wire varies at different positions, resulting in different magnetic induction intensities. Therefore, the induced electromotive force generated by the pantograph cutting magnetic lines of force at different positions is different. It is necessary to combine equations (1) and (2) for each line element. dL Integrating the motional electromotive force generated by cutting the magnetic field lines, we obtain the motional electromotive force generated by the pantograph cutting the magnetic field lines as shown in equation (3). At this time, it is assumed that the pantograph and the contact line are in ideal contact, that is, the distance between them is 0. Then the distance from the pantograph to the center point of the contact line is the radius of the contact line.

[0047] (3);

[0048] In the formula, E To generate an electromotive force. n This is the vertical distance between the roof and the contact line. r Where is the radius of the contact line. The permeability of free space, I For the current on the contact wire, L The length of the upper and lower arms of the pantograph that cuts the magnetic field lines. v This refers to the cutting speed.

[0049] When solving equation (3), it was found that if the initial value is 0, the integral result is infinite, making it impossible to perform voltage source equivalence. Furthermore, in reality, even when the pantograph and contact wire are in contact, there will inevitably be a gap between them. Therefore, an initial value of 1 is chosen here. The motional electromotive force generated by the pantograph cutting the magnetic field lines is obtained as follows:

[0050] (4);

[0051] By considering the pantograph's kinetic electromotive force as an equivalent voltage source with amplitude E and frequency of 50Hz, and placing it between the contact wire and the vehicle roof, a vehicle-grid model of the pantograph cutting magnetic lines of force can be obtained, such as... Figure 6 As shown.

[0052] S4: Connect one end of the equivalent voltage source to the contact wire T (Trolley and contact wires for electric traction) that is slidably connected to the pantograph in the chain lumped τ-type network model, and connect the other end to the top of the train model. Connect the bottom of the train model to the rail R to obtain the vehicle-network model under the condition of pantograph cutting magnetic lines of force.

[0053] Given the equivalent impedance of the train head, the equivalent impedance of the carriages, the equivalent resistance of the grounding resistor, the connection resistance between the carriages, and the equivalent resistance of the grounding carbon brush, establish... Figure 5 The train model shown.

[0054] This invention provides a modeling method for a train-grid model of pantograph cutting magnetic field lines in high-speed trains. This method can simulate the impact of pantograph cutting magnetic field lines on the train and various lines of the traction power supply system at different train speeds, providing a theoretical basis and technical support for the electromagnetic protection design of electrified railways. Furthermore, an equivalent model of pantograph cutting magnetic field lines can be added to simulations of rail transit circuits under other operating conditions, making the simulation results more consistent with reality and reducing errors.

[0055] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0056] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for modeling a vehicle-grid model under the condition of pantograph cutting magnetic field lines, characterized in that, Includes the following steps: The self-impedance and ground admittance of the traction network contact wire that is slidably connected to the pantograph when the train is running, as well as the self-impedance and ground admittance of the rail on which the train is running, are obtained. Based on the self-impedance and ground admittance of the contact wire, the self-impedance and ground admittance of the rail, and the mutual impedance between the contact wire and the rail, a unit length lumped τ-type circuit of the traction network is constructed. By cascading unit-length lumped τ-type circuits, a chain-type lumped τ-type network model of the traction network is obtained; The motional electromotive force generated during train operation is used as an equivalent voltage source. During the sliding process of the pantograph, the current in the upper and lower arms cutting the contact wire generates magnetic lines of force in the magnetic field, thus generating motional electromotive force. One end of the equivalent voltage source is connected to the contact line that is slidably connected to the pantograph in the chain lumped τ-type network model, and the other end is connected to the top of the train model. The bottom of the train model is connected to the rail, thus obtaining the vehicle-network model under the condition of pantograph cutting magnetic lines of force. The motional electromotive force is as follows: ； In the formula, E To generate an electromotive force. n This is the vertical distance between the roof and the contact line. r Where is the radius of the contact line. The permeability of free space, I For the current on the contact wire, L The length of the upper and lower arms of the pantograph that cuts the magnetic field lines. v This refers to the cutting speed.

2. The method for modeling a vehicle-grid model under the condition of pantograph cutting magnetic lines of force as described in claim 1, characterized in that, A train model is constructed based on the equivalent impedance of the train head, the equivalent impedance of the carriages, the equivalent resistance of the grounding resistor, the connection resistance between the carriages, and the equivalent resistance of the grounding carbon brush.

3. The method for modeling a vehicle-grid model under the condition of pantograph cutting magnetic lines of force as described in claim 1, characterized in that, The vehicle network model also includes a traction transformer, whose output terminals are connected to the contact wire and the rail, respectively.

4. A modeling system based on the pantograph cutting magnetic field lines modeling method described in claim 1, characterized in that, include: The module is used to obtain the self-impedance and ground admittance of the traction network contact wire that is slidably connected to the pantograph when the train is running, as well as the self-impedance and ground admittance of the rail on which the train is running. Based on the self-impedance and ground admittance of the contact wire, the self-impedance and ground admittance of the rail, and the mutual impedance between the contact wire and the rail, a unit length lumped τ-type circuit of the traction network is constructed. The cascade module is used to cascade unit-length lumped τ-type circuits to obtain a chain-type lumped τ-type network model of the traction network; The cutting module is used to use the motional electromotive force generated during train operation as an equivalent voltage source. During the sliding process of the pantograph, its upper and lower arms cut the contact wire current to generate magnetic lines of force in the magnetic field, thus generating motional electromotive force. The connection module is used to connect one end of the equivalent voltage source to the contact line that is slidably connected to the pantograph in the chain lumped τ-type network model, and the other end to the top of the train model. The bottom end of the train model is connected to the rail, thus obtaining the train-network model under the condition of the pantograph cutting magnetic lines of force.

Images