Train power supply cabinet with grounding resistance loop and railway passenger car

Abstract

The present invention discloses a train power supply cabinet and a railway passenger car with a grounding resistance loop, wherein the power supply cabinet includes: a first power supply cabinet LG1 and a second power supply cabinet LG2 respectively connected to the vehicle load; wherein the first power supply cabinet LG1 includes a first AC power supply circuit and a first grounding resistor GRe1, one side of the first AC power supply circuit is connected to the vehicle load to provide the vehicle load with a first AC power, and the other side is grounded through the first grounding resistor GRe1; the second power supply cabinet LG2 includes a second AC power supply circuit and a second grounding resistor GRe2, one side of the second AC power supply circuit is connected to the vehicle load to provide the vehicle load with a second AC power, and the other side is grounded through the second grounding resistor GRe2. The two AC power supply circuits of the train power supply cabinet described in the present invention are electrically independent of each other and solve the problem of being unable to correctly detect leakage by adding a grounding resistor in the grounding loop.

Description

Technical Field

[0001] The present invention relates to the technical field of train power supply, and in particular to a train power supply cabinet with a grounding resistance loop. Background Art

[0002] Railway passenger cars utilize a centralized power supply system from electric locomotives. Currently, the power supply circuit for train power supply cabinets is mostly located on the vehicle side, often sharing the neutral line of two AC circuits. Under these conditions, two-point grounding on the locomotive side prevents accurate leakage detection. Furthermore, if a ground fault occurs, both power supply systems will detect the fault simultaneously, causing both systems to shut down. Another traditional power supply method uses a generator car to drive a generator. However, generators are prone to ground faults, and since the motors themselves don't detect ground faults internally, the corresponding grounding function is located inside the carriages. However, this detection method suffers from poor sensitivity and accuracy. Summary of the Invention

[0003] Based on this, a train power supply cabinet with a grounding resistance loop is proposed to prevent the occurrence of the above problems.

[0004] In order to achieve the above object, the technical solution of the present invention is:

[0005] A train power supply cabinet with a grounding resistance circuit, characterized in that the power supply cabinet includes: a first power supply cabinet LG1 and a second power supply cabinet LG2 respectively connected to the vehicle load; wherein the first power supply cabinet LG1 includes a first AC power supply circuit and a first grounding resistor GRe1, one side of the first AC power supply circuit is connected to the vehicle load to provide a first AC power to the vehicle load, and the other side is grounded through the first grounding resistor GRe1; the second power supply cabinet LG2 includes a second AC power supply circuit and a second grounding resistor GRe2, one side of the second AC power supply circuit is connected to the vehicle load to provide a second AC power to the vehicle load, and the other side is grounded through the second grounding resistor GRe2.

[0006] Optionally, in one embodiment, the first AC power supply circuit includes at least a first multi-phase transformer Tr1, a first AC output contactor ACMK1, and a first leakage current sensor GCT1; the first AC output contactor ACMK1 is connected to a power supply bus of the vehicle load, and provides three-phase AC power to the vehicle load through the first power supply contactor K1 on one side of the vehicle power supply bus, and the N phase of the first multi-phase transformer Tr1 is connected to the first grounding resistor GRe1 and grounded through the first current sensor GCT1.

[0007] Optionally, in one embodiment, the second AC power supply circuit includes at least a second multi-phase transformer Tr2, a second AC output contactor ACMK2, and a second leakage current sensor GCT2; the second AC output contactor ACMK2 is connected to another power supply bus of the vehicle load, and provides three-phase AC power to the vehicle load through the second power supply contactor K2 on one side of the vehicle power supply bus, and the N phase of the second multi-phase transformer Tr2 is connected to the second grounding resistor GRe2 and grounded through the second current sensor GCT2.

[0008] Optionally, in one embodiment, the resistance of the first grounding resistor GRe1 / the second grounding resistor GRe2 is 20 ohms.

[0009] Based on the same inventive concept, the present invention also provides a railway passenger car having the train power supply cabinet.

[0010] The implementation of the present invention will have the following beneficial effects:

[0011] First, the two lines of the train power supply cabinet described in the present invention are electrically independent of each other, and the two outputs are respectively connected to the two power supply busbars of the vehicle load. When a single line fails, it will not affect the normal power supply of the other line. The entire train runs with reduced load, and the other power supply is responsible for supplying power to the entire train. Secondly, without changing the structure and power supply circuit of the original train power supply cabinet, the newly designed power supply circuit, especially the circuit with added grounding resistance, solves the problem of being unable to correctly detect leakage. That is, the present invention has the advantages of saving maintenance costs and not affecting the normal operation of the complete circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0013] in:

[0014] Figure 1 This is a structural framework diagram of a train power supply cabinet implemented in one embodiment;

[0015] Figure 2 This is a framework diagram of the technical principle of implementing a train power supply cabinet (adding grounding resistance) in one embodiment; DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the technical field of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. It will be understood that the terms "first", "second", etc. used in the present invention can be used to describe various elements in this article, but these elements are not limited by these terms. These terms are only used to distinguish the first element from another element. For example, without departing from the scope of this application, the first element can be referred to as the second element, and similarly, the second element can be the first element. Both the first element and the second element are elements, but they are not the same element.

[0018] In this embodiment, a train power supply cabinet with a grounding resistance loop is proposed, which is particularly suitable for use in dual-mode compatible train power supply; Figure 1-Figure 2 As shown, the train power supply cabinet is characterized in that the power supply cabinet includes: a first power supply cabinet LG1 and a second power supply cabinet LG2 respectively connected to the vehicle load; wherein, the first power supply cabinet LG1 includes a first AC power supply circuit and a first grounding resistor GRe1, one side of the first AC power supply circuit is connected to the vehicle load to provide the vehicle load with a first AC power, and the other side is grounded through the first grounding resistor GRe1; the second power supply cabinet LG2 includes a second AC power supply circuit and a second grounding resistor GRe2, one side of the second AC power supply circuit is connected to the vehicle load to provide the vehicle load with a second AC power, and the other side is grounded through the second grounding resistor GRe2.

[0019] According to the above scheme, the two lines of the train power supply cabinet described in the present invention are electrically independent of each other, and the two outputs are respectively connected to the two power supply busbars. When a single line fails, it will not affect the normal power supply of the other line. The entire train runs with reduced load, and the other power supply is responsible for powering the entire train. At the same time, in order to cope with the problem that the N-phase current of the conventional design returns to the N-phase through the grounding loop, causing the leakage current to be unable to be correctly detected, a circuit design with a grounding resistor is used to ensure that the overall operation of the train power supply cabinet is not affected, while maintaining the original size of the train supply device unchanged, the existing mechanical interface and the cooling system interface unchanged, and avoiding the cross-flow of the N-phase current without affecting the normal operation of the complete circuit.

[0020] In some specific embodiments, the first AC power supply circuit includes at least a first multi-phase transformer Tr1, a first AC output contactor ACMK1, and a first current transformer GCT1; one side of the first AC output contactor ACMK1 is connected to the vehicle load (connected to the vehicle power supply bus 1 through a jumper cable between the locomotive and the vehicle), and the other side is connected to the first multi-phase transformer Tr1; the other side of the first multi-phase transformer Tr1 is connected to the first grounding resistor GRe1 through the first current transformer GCT1. Figure 2 The three output terminals of the first multi-phase transformer Tr1 are respectively connected to the contacts 153, 154, and 155 of the first AC output contactor ACMK1; one end of the neutral point of the first multi-phase transformer Tr1 is connected to the contact 156 of the DC power supply-first AC output contactor ACMK1, and the other end is connected to the first current transformer GCT1; the other end of the first current transformer GCT1 is connected to the first grounding resistor GRe1; the other end of the first grounding resistor GRe1 is grounded; the other ends of the contacts 153, 154, and 155 of the first AC output contactor ACMK1 are coupled to the input end of the first power supply contactor K1; the first power supply contactor The three output ends of K1 are coupled with the vehicle load; the other end of the 156 contacts of the first AC contactor ACMK1 is connected to the vehicle load; based on the above structure, it can be seen that the first AC output contactor ACMK1 of this circuit is connected to the vehicle power supply bus 1 through the jumper cable between the locomotive and the vehicle, and provides three-phase AC power to the vehicle load through the first power supply contactor K1 on one side of the vehicle power supply bus 1, and returns to the first AC power supply circuit of the first power supply cabinet LG1 through the rails between the vehicle and the locomotive to output the N phase of the first multi-phase transformer Tr1. The N phase of the first multi-phase transformer Tr1 is connected to the first grounding resistor GRe1 through the first current sensor GCT1 to be grounded.

[0021] In some specific embodiments, the second AC power supply circuit includes at least a second multi-phase transformer Tr2, a second AC output contactor ACMK2, and a second current transformer GCT2; one side of the second AC output contactor ACMK2 is connected to the vehicle load, and the other side is connected to the second multi-phase transformer Tr2; the other side of the second multi-phase transformer Tr2 is connected to the second grounding resistor GRe2 through the second current transformer GCT2; Figure 2The three output ends of the second multi-phase transformer Tr2 are respectively connected to contacts 153, 154, and 155 of the second AC output contactor ACMK2; one end of the neutral point of the second multi-phase transformer Tr2 is connected to contact 156 of the second AC output contactor ACMK2, and the other end is connected to the second current transformer GCT2; the other end of the second current transformer GCT2 is connected to the second grounding resistor GRe2; the other end of the second grounding resistor GRe2 is grounded; the other ends of contacts 153, 154, and 155 of the second AC output contactor ACMK2 are coupled to the input end of the second power supply contactor K2; the three output ends of the second power supply contactor K2 are coupled to the vehicle load output end; the other end of contact 156 of the second AC output contactor ACMK2 is simultaneously connected to contact 156 of the first AC output contactor ACMK1 and the vehicle load. Based on the above structure, the second AC output contactor ACMK2 of this circuit is connected to the vehicle power supply bus 2 via a jumper cable between the locomotive and the vehicle. Three-phase AC power is supplied to the vehicle load via the second power supply contactor K2 on one side of the vehicle power supply bus 2. This power is then returned to the AC power supply circuit of the second power supply cabinet LG2 via the rails between the vehicle and the locomotive, outputting the N phase of the second multiphase transformer Tr2. The N phase of the second multiphase transformer Tr2 is grounded via the second current sensor GCT2, connected to the second grounding resistor GRe2. The first and second current sensors GCT1 and GCT2 are each used to detect leakage current in their respective power supply circuits.

[0022] The above-mentioned train power supply cabinet can not only effectively power the train, but also detect ground faults in various systems while avoiding false detection of leakage current. The corresponding technical principles are as follows:

[0023] like Figure 2 The direction of the N-phase current is shown by the thick line. During leakage current detection, the N-phase current will be mixed with the N-phase current. Since the N-phase current enters the grounding loop, it will cause errors in leakage current detection, resulting in false detection. The N-phase current interference problem is solved by designing a circuit inside the power supply cabinet and adding two grounding resistors.

[0024] Therefore, two parallel grounding resistors are added to the two AC power supply circuits. For example, a 20Ω grounding resistor is added to the grounding loop corresponding to the AC power supply circuit of each power supply cabinet. Figure 1As shown, due to the impedance of the two newly added grounding resistors, the N-phase current does not pass through the ground loop. This eliminates the problem of N-phase current entering the ground loop and causing leakage current detection. Furthermore, selecting a 20-ohm grounding resistor does not affect leakage detection performance. For example, if the current leakage detection value is 300mA, this means that a leakage of (400V / √3) ÷ 0.3A = 770Ω must be detected. However, with a grounding resistor of only 20Ω, the difference is only 2.6%. Detection will occur when the leakage level reaches 750Ω, with virtually no impact on leakage detection performance.

[0025] The reason why the grounding resistance is selected as 20Ω is because this resistance value is suitable for most locomotive power supply cabinets. The specific calculation formula is shown as follows:

[0026] R lc =(U rms / √3) / I lc

[0027] R e =R lc ×K e

[0028] Among them, U rms Indicates the voltage of the power supply system, I lc Represents the leakage detection threshold, R lc Indicates the leakage detection threshold I lc The corresponding equivalent impedance, R e Indicates the resistance of the grounding resistor, and its corresponding proportional coefficient K e , the usual value range is 2% to 5%.

[0029] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A train power supply cabinet with a grounding resistance circuit, characterized in that: The power supply cabinet includes: a first power supply cabinet LG1 and a second power supply cabinet LG2 respectively connected to the vehicle load; wherein, the first power supply cabinet LG1 includes a first AC power supply circuit and a first grounding resistor GRe1, one side of the first AC power supply circuit is connected to the vehicle load, for providing a first AC power to the vehicle load, and the other side is grounded through the first grounding resistor GRe1; the second power supply cabinet LG2 includes a second AC power supply circuit and a second grounding resistor GRe2, one side of the second AC power supply circuit is connected to the vehicle load, for providing a second AC power to the vehicle load, and the other side is grounded through the second grounding resistor GRe2; The first AC power supply circuit includes at least a first multi-phase transformer Tr1, a first AC output contactor ACMK1, and a first leakage current sensor GCT1; the first AC output contactor ACMK1 is connected to a power supply bus of the vehicle load and provides three-phase AC power to the vehicle load through a first power supply contactor K1 on one side of the vehicle power supply bus. The N phase of the first multi-phase transformer Tr1 is connected to a first grounding resistor GRe1 through a first current sensor GCT1 and is grounded; The second AC power supply circuit includes at least a second multi-phase transformer Tr2, a second AC output contactor ACMK2, and a second leakage current sensor GCT2; the second AC output contactor ACMK2 is connected to another power supply bus of the vehicle load, and provides three-phase AC power to the vehicle load through the second power supply contactor K2 on one side of the vehicle power supply bus. The N phase of the second multi-phase transformer Tr2 is connected to the second grounding resistor GRe2 through the second current sensor GCT2 and is grounded; The resistance of the first grounding resistor GRe1 and the second grounding resistor GRe2 is 20 ohms; wherein the first grounding resistor GRe1 and the second grounding resistor GRe2 are used to suppress the N-phase current from entering the grounding loop to prevent it from affecting the leakage current detection.

2. A railway passenger car, characterized in that: It comprises the train power supply cabinet according to claim 1.

Images