A dual-current traction return rail and track electrical monitoring system

Abstract

The embodiment of the present application provides a dual-current traction return rail and an on-track electrical monitoring system, which relate to the technical field of rail transit and are used to solve the problems that the electrical isolation scheme of the dual-current traction return system is too simple and the insulation strength is insufficient. The dual-current traction return rail provided by the embodiment of the present application includes a DC section rail, an AC section rail, and a conversion section rail. Among them, the DC section rail is used to form a DC traction network with the DC catenary; the AC section rail is used to form an AC traction network with the AC catenary; the conversion section rail is connected between the DC section rail and the AC section rail, and insulating joints are connected to both ends of the conversion section rail so that both the DC section rail and the AC section rail are insulated from the conversion section rail. The length of the conversion section rail is greater than or equal to the length of the train, and the conversion section rail is arranged corresponding to the neutral section between the DC catenary and the AC catenary. The dual-current traction return rail provided by the embodiment of the present application is used for the passage of dual-current rail trains.

Description

Technical Field

[0001] This application relates to the technical field of rail transit, and particularly to a dual - current traction return rail and an on - track electrical monitoring system. Background Art

[0002] The traction power supply system is used to supply power to rail transit trains running along the line. The power from the regional power grid is transmitted to the trains through the catenary of the traction power supply system. Dual - current rail transit trains are equipped with two types of converters, DC and AC, and can switch between them. For urban rail transit lines, the proportion of underground lines is high, the station layout is dense, and the train running speed is low, so generally the DC traction power supply system is adopted; for suburban rail transit lines, the proportion of over - ground sections is large, the station layout is sparse, and the train running speed is high, so generally the AC traction power supply system is adopted. Dual - current rail transit trains usually need to conduct traction power supply return. Generally, the running wheels of the train are used for return, and the running rails are used as the return conductor. The running wheels are in contact with the return conductor, so that the power from the catenary flows back to the traction substation through the running rails.

[0003] The return characteristics of the two traction power supply systems are different. For the AC traction power supply system, the rail - to - ground potential is mainly composed of AC components, and the running rails need to be grounded through the neutral point of the impedance bond or directly grounded; for the DC traction power supply system, the rail - to - ground potential is mainly composed of DC components. Due to the consideration of stray current protection, the running rails are installed in an insulated manner. In order to limit the mutual influence between the two traction return networks, in addition to the catenary needing to be provided with a neutral section, the running rails also need to be electrically isolated. However, in the implementation of relevant engineering projects, the electrical isolation scheme of the dual - current traction return system is too simple and the insulation strength is insufficient. Summary of the Invention

[0004] In view of this, the embodiments of this application provide a dual - current traction return rail and an on - track electrical monitoring system, which are used to solve the problems that the electrical isolation scheme of the dual - current traction return system is too simple and the insulation strength is insufficient.

[0005] In a first aspect, the embodiments of this application provide a dual - current traction return rail, which includes a DC - section rail, an AC - section rail, and a conversion - section rail. Among them, the DC - section rail is used to form a DC traction network with the DC catenary; the AC - section rail is used to form an AC traction network with the AC catenary; the conversion - section rail is connected between the DC - section rail and the AC - section rail, and insulating joints are connected to both ends of the conversion - section rail, so that both the DC - section rail and the AC - section rail are insulated from the conversion - section rail. The length of the conversion - section rail is greater than or equal to the length of the train, and the conversion - section rail is arranged corresponding to the neutral section between the DC catenary and the AC catenary.

[0006] In some alternative embodiments of the present application, the transition section rail includes a main transition section rail and an auxiliary transition section rail. Among them, the length of the main transition section rail is greater than or equal to the length of the train; the auxiliary transition section rail is connected to the main transition section rail through an insulating joint, and at least one end of the main transition section rail is connected with the auxiliary transition section rail.

[0007] In some alternative embodiments of the present application, the length of the auxiliary transition section rail is the standard rail length or half of the standard rail length.

[0008] In some alternative embodiments of the present application, the transition section rail is fixed by insulating fasteners; and / or, the transition section rail is supported on insulating sleepers.

[0009] In a second aspect, an embodiment of the present application provides an on-rail electrical monitoring system, which includes an insulation monitoring device and the dual-system traction return rail provided in the first aspect of the embodiment of the present application. Among them, the insulation monitoring device is used to monitor the insulation condition of the transition section rail to the ground.

[0010] In some alternative embodiments of the present application, the insulation monitoring device monitors the insulation condition of the transition section rail to the ground by using two test voltages of alternating current and direct current.

[0011] In a third aspect, an embodiment of the present application provides an on-rail electrical monitoring system, which includes a rail potential monitoring device and the dual-system traction return rail provided in the first aspect of the embodiment of the present application. Among them, the rail potential monitoring device is used to monitor the potential difference between the dual-system traction return rail and the ground, and / or, is used to monitor the potential difference between two sections of the dual-system traction return rail, and there is an insulating joint between the two sections of the rail.

[0012] In some alternative embodiments of the present application, the transition section rail includes a main transition section rail and an auxiliary transition section rail, the auxiliary transition section rail is connected to the main transition section rail through an insulating joint, at least one end of the main transition section rail is connected with the auxiliary transition section rail, and the rail potential monitoring device is used to monitor the ground potential of the DC section rail, the AC section rail, the main transition section rail and the auxiliary transition section rail.

[0013] In some alternative embodiments of the present application, the on-rail electrical monitoring system further includes a recording device, the recording device is electrically connected to the output end of the rail potential monitoring device, and the recording device is used to record the dynamic data of the output signal of the rail potential monitoring device.

[0014] In some alternative embodiments of the present application, the track electrical monitoring system further includes a train sensing device, which starts and stops the waveform recording device by detecting the train passing condition of the conversion section rail. The dual-system traction return rail provided by the embodiments of the present application is provided with an insulating joint at the end of the conversion section rail, so that the DC section rail, the conversion section rail and the AC section rail are insulated from each other in pairs, and the DC current and the AC current can return through their respective expected paths, achieving the purpose of isolating the DC section rail from the AC section rail, and having a lower construction difficulty and a lower project investment. In addition, the length of the conversion section rail is greater than or equal to the length of the train, so that during the process of the train switching between the two traction networks, the DC section rail and the AC section rail will not be in contact with the train running wheels at the same time, thereby completely isolating the two power supply systems, effectively restricting the diffusion range of stray current, and avoiding the problem of dangerous overvoltage caused by the superposition of the rail potentials of the dual-system traction return system. Therefore, the dual-system traction return rail provided by the embodiments of the present application solves the problems of the electrical isolation scheme of the dual-system traction return system being too simple and the insulation strength being insufficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic diagram of the dual-system traction return rail in some embodiments of the present application;

[0016] Figure 2 is a schematic diagram of the track electrical monitoring system in some embodiments of the present application.

[0017] REFERENCE SIGNS:

[0018] 10 - DC section rail; 20 - AC section rail; 30 - conversion section rail; 301 - main conversion section rail; 302 - auxiliary conversion section rail; 401 - first joint; 402 - second joint; 403 - third joint; 404 - fourth joint; 60 - rail potential and insulation comprehensive monitoring device; 70 - train sensing device; 80 - connecting line; a - driving direction. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] It should be noted that, without conflict, the embodiments in the present application and the technical features in the embodiments can be combined with each other. The detailed description in the specific implementation manners should be understood as an explanatory illustration of the purpose of the present application and should not be regarded as an improper limitation of the present application.

[0020] In the embodiments of the present application, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present application, unless otherwise stated, the meaning of "a plurality" is two or more.

[0021] In addition, in the embodiments of the present application, orientation terms such as "upper", "lower", "left", and "right" are defined relative to the orientation in which the components in the drawings are schematically placed. It should be understood that these directional terms are relative concepts, which are used for relative description and clarification, and they can change accordingly with the change of the orientation in which the components in the drawings are placed.

[0022] In the embodiments of the present application, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or integrated; it can be directly connected or indirectly connected through an intermediate medium.

[0023] In the embodiments of the present application, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the presence of additional identical elements in the process, method, article or device including the element.

[0024] In the embodiments of the present application, words such as "exemplary" or "for example" are used to represent examples, illustrations or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of the present application should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Rather, the use of words such as "exemplary" or "for example" is intended to present relevant concepts in a specific manner.

[0025] The embodiments of the present application provide a dual-current traction return rail. Please refer to Figure 1 and Figure 2 , the dual-current traction return rail includes a DC section rail 10, an AC section rail 20 and a conversion section rail 30. Among them, the DC section rail 10 is used to form a DC traction network with the DC catenary; the AC section rail 20 is used to form an AC traction network with the AC catenary. The conversion section rail 30 is connected between the DC section rail 10 and the AC section rail 20. Insulating joints are connected to both ends of the conversion section rail 30 so that both the DC section rail 10 and the AC section rail 20 are insulated from the conversion section rail 30. The length of the conversion section rail 30 is greater than or equal to the length of the train, and the conversion section rail 30 is arranged corresponding to the neutral section between the DC catenary and the AC catenary.

[0026] The dual-current traction return rail provided by the embodiment of the present application is provided with an insulating joint at the end of the conversion section rail 30, so that the DC section rail 10, the conversion section rail 30 and the AC section rail 20 are insulated from each other in pairs. The DC current and the AC current can return through their respective desired paths, achieving the purpose of isolating the DC section rail 10 from the AC section rail 20, and the construction difficulty is relatively low and the project investment is relatively low. In addition, the length of the conversion section rail 30 is greater than or equal to the length of the train, so that during the switching process of the train between the two traction networks, the DC section rail 10 and the AC section rail 20 will not be in contact with the running wheels of the train at the same time, thereby completely isolating the two traction networks, effectively restricting the diffusion range of stray current, and avoiding the problem of dangerous overvoltage caused by the superposition of the rail potentials of the dual-current traction return system. Therefore, the dual-current traction return rail provided by the embodiment of the present application solves the problems that the electrical isolation scheme of the dual-current traction return system is too simple and the insulation strength is insufficient.

[0027] In some alternative embodiments of the present application, the dual-current traction return rail may include an up-track and a down-track. Both the up-track and the down-track include a DC section rail 10, an AC section rail 20 and a conversion section rail 30, and the DC section rail 10, the AC section rail 20 and the conversion section rail 30 of the up-track are arranged corresponding to the DC section rail 10, the AC section rail 20 and the conversion section rail 30 of the down-track.

[0028] It should be noted that, please refer to Figure 1 and Figure 2 , the DC catenary refers to the catenary used to transmit DC current to the train, and the AC catenary refers to the catenary used to transmit AC current to the train. The DC section rail 10 is used to form a DC traction network with the DC catenary, which means that the current of the DC catenary returns to the DC traction substation through the DC section rail 10. The AC section rail 20 is used to form an AC traction network with the AC catenary, which means that the current of the AC catenary returns to the AC traction substation through the AC section rail 20.

[0029] It should be noted that, please refer to Figure 1 and Figure 2 , the arrangement directions of the DC section rail 10, the conversion section rail 30 and the AC section rail 20 are parallel to the driving direction of the train. One end of the conversion section rail 30 is connected to the end of the DC section rail 10 through an insulating joint, and the other end of the conversion section rail 30 is connected to the end of the AC section rail 20 through an insulating joint. The train can travel from the DC section rail 10 to the AC section rail 20 through the conversion section rail 30, and the train can also travel from the AC section rail 20 to the DC section rail 10 through the conversion section rail 30.

[0030] It should be explained that there is no limit to the number of train carriages. A train can have only one carriage or multiple carriages, and the train length refers to the distance between the running wheels at the front end and the running wheels at the rear end of the train, that is, the distance between the two farthest running wheels of the train.

[0031] It can be understood that since the transition section rail 30 corresponds to the electrical phase separation zone between the DC contact network and the AC contact network, when the train is completely located on the transition section rail 30, that is, when the frontmost running wheels of the train and the rearmost running wheels of the train are both located on the transition section rail 30, the DC contact network and the AC contact network are electrically isolated from the train.

[0032] There are many ways to implement the insulating joint. In some optional embodiments of the present application, the insulating joint can be a mechanical insulating joint or an electrical insulating joint.

[0033] Furthermore, in some optional embodiments of the present application, the transfer rail 30 includes a primary transfer rail 301 and an auxiliary transfer rail 302. The primary transfer rail 301 is longer than or equal to the length of the train; the auxiliary transfer rail 302 is connected to the primary transfer rail 301 via an insulating joint, with at least one end of the primary transfer rail 301 connected to the auxiliary transfer rail 302. This structural form increases the number of insulating joints between the DC rail 10 and the AC rail 20, thereby improving electrical isolation.

[0034] It is understood that if auxiliary transfer-segment rails 302 are connected to both ends of the main transfer-segment rail 301, there are at least four sets of insulating joints between the DC rail 10 and the AC rail 20. Specifically, one auxiliary transfer-segment rail 302 is connected to one of the DC rail 10 and the AC rail 20 via an insulating joint, and another auxiliary transfer-segment rail 302 is connected to the other of the DC rail 10 and the AC rail 20 via an insulating joint. The main transfer-segment rail 301 is connected between the two auxiliary transfer-segment rails 302.

[0035] It should be explained that the traction return rail may include only one steel rail, that is, the traction return rail may be a single rail, or may include multiple steel rails arranged side by side. Figure 1 and Figure 2, the traction return rail consists of two side-by-side steel rails. The number of insulated joints included in a set of insulated joints is the same as the number of steel rail strands included in the traction return rail. Exemplarily, if the traction return rail is a single rail, a set of insulated joints includes only one insulated joint. If the traction return rail consists of two side-by-side steel rails, the number of insulated joints included in a set of insulated joints is two, and the two insulated joints are respectively arranged on the two steel rails and are oppositely arranged. Specifically, the conversion section rail 30 is connected to the DC section rail 10 and the AC section rail 20 through two sets of insulated joints respectively arranged at both ends of the conversion section rail 30. On the basis that the conversion section rail 30 includes the main conversion section rail 301 and the auxiliary conversion section rail 302, the auxiliary conversion section rail 302 is separated from the main conversion section rail 301 through the corresponding set of insulated joints.

[0036] If only one end of the main conversion section rail 301 is connected to the auxiliary conversion section rail 302, there are at least three sets of insulated joints between the DC section rail 10 and the AC section rail 20. Specifically, the auxiliary conversion section rail 302 is connected to one of the DC section rail 10 and the AC section rail 20 through an insulated joint, and the main conversion section rail 301 is connected to the other of the DC section rail 10 and the AC section rail 20 through an insulated joint.

[0037] It should be explained that both the auxiliary conversion section rail 302 and the main conversion section rail 301 extend along the driving direction for trains to pass through, and there is electrical isolation between the auxiliary conversion section rail 302 and the main conversion section rail 301.

[0038] Optionally, please refer to Figure 1 and Figure 2 , in some embodiments of the present application, both ends of the main conversion section rail 301 are connected to the auxiliary conversion section rail 302. In this way, since the length of the main conversion section rail 301 is greater than the length of the train, during the process of the train passing through the conversion section rail 30, the two different traction networks are always in a state separated by at least two sets of insulated joints.

[0039] Specifically, please refer to Figure 1 and Figure 2, for the convenience of description, along the driving direction a, in the DC section rail 10 and the AC section rail 20, the one at the head end in the driving direction a is called the first section rail, and the one at the tail end in the driving direction a is called the second section rail. Among the auxiliary conversion section rails 302 on both sides, the one close to the first section rail is called the first auxiliary conversion section rail, and the one close to the second section rail is called the second auxiliary conversion section rail. The insulating joint between the first auxiliary conversion section rail and the first section rail is called the first joint 401, the insulating joint between the first section rail and the main conversion section rail 301 is called the second joint 402, the insulating joint between the second section rail and the main conversion section rail 301 is called the third joint 403, and the insulating joint between the second auxiliary conversion section rail and the second section rail is called the fourth joint 404. During the train operation, when the train straddles the first section rail and the first auxiliary conversion section rail, the first joint 401 fails, and the main conversion section rail 301 and the second auxiliary conversion section rail can effectively isolate the two different traction return networks; when the train straddles the first section rail, the first auxiliary conversion section rail and the main conversion section rail 301, both the first joint 401 and the second joint 402 fail, but the second auxiliary conversion section rail can still effectively isolate the two different traction return networks; the length of the main conversion section rail 301 is greater than the length of the train. Before the pair of running wheels closest to the head of the train reach the second auxiliary conversion section rail, the pair of running wheels closest to the tail of the train will first pass through the end of the first auxiliary conversion section rail, and at this time, the two different traction return networks can be effectively isolated; when the train straddles the main conversion section rail 301 and the second auxiliary conversion section rail, there is at least one set of insulating joints between the end of the train's head and the second section rail, and at least two sets of insulating joints between the end of the train's tail and the first section rail, and at this time, the two different traction networks can be effectively isolated; when the train straddles the main conversion section rail 301, the second auxiliary conversion section rail and the second section rail, both the third joint 403 and the fourth joint 404 are insulated and ineffective, but the first auxiliary conversion section rail can effectively isolate the two different traction return networks.

[0040] Optionally, in some embodiments of the present application, multiple sets of insulating joints can be provided on the auxiliary conversion section rail 302 to improve the insulation effect of the auxiliary conversion section rail 302. Specifically, the auxiliary conversion section rail 302 includes multiple sub-auxiliary conversion section rails, and the multiple sub-auxiliary conversion section rails are arranged along the driving direction a, and insulating joints are provided between every two adjacent sub-auxiliary conversion section rails. In this way, it is beneficial to improve the insulation effect. Similarly, optionally, in some embodiments of the present application, multiple sets of insulating joints can also be provided on the main conversion section rail 301 to improve the insulation effect of the main conversion section rail 301.

[0041] Optionally, please refer to Figure 1 and Figure 2, in some embodiments of the present application, the length of the auxiliary conversion section rail 302 is the standard rail length or half of the standard rail length, which is convenient for processing, manufacturing and construction. Moreover, the shorter length of the auxiliary conversion section rail 302 is beneficial to improving the ground insulation effect of the auxiliary conversion section rail 302. On this basis, in some embodiments of the present application, the length of the auxiliary conversion section rail 302 can be 25 meters or 12.5 meters.

[0042] Optionally, please refer to Figure 1 and Figure 2 , taking the train formed by eight A-type carriages as an example, in some embodiments of the present application, the length of the main conversion section rail 301 is greater than or equal to 180 meters. In this way, the length of the main conversion section rail is relatively long, ensuring that at least two sets of rail insulation joints are effective during the train passing through the conversion section, so as to improve the electrical isolation effect.

[0043] Furthermore, in some alternative embodiments of the present application, the conversion section rail 30 is fixed by insulating fasteners; and / or, the conversion section rail 30 is supported on insulating sleepers. In this way, it can be avoided that the conversion section rail 30 is electrically connected to the ground, and further, it can be avoided that it is electrically connected to the DC section rail 10 and the AC section rail 20, greatly improving the electrical isolation effect of the conversion section rail 30. Optionally, please refer to Figure 1 and Figure 2 , in some embodiments of the present application, the conversion section rail 30 includes a main conversion section rail 301 and an auxiliary conversion section rail 302, and both the main conversion section rail 301 and the auxiliary conversion section rail 302 are fixed by insulating fasteners; and / or, both the main conversion section rail 301 and the auxiliary conversion section rail 302 are supported on insulating sleepers.

[0044] Furthermore, please refer to Figure 1 and Figure 2 , the embodiment of the present application further provides an on-rail electrical monitoring system, which includes an insulation monitoring device and a dual-current traction return rail. Among them, the insulation monitoring device is used to monitor the ground insulation condition of the conversion section rail 30. The insulation effect of the conversion section rail 30 will change continuously with the external environment and the operation years. Setting the insulation monitoring device is beneficial for the operation personnel to accurately judge the ground insulation condition of the conversion section rail 30 and facilitate the later maintenance. It should be noted that the measurement of the ground insulation resistance should be carried out when the insulation state between the conversion section rail 30 and the DC section rail 10 is normal and effective, the insulation state between the conversion section rail 30 and the AC section rail 20 is normal and effective, and there is no train passing through the conversion section rail 30. Optionally, in some implementations of the present application, the conversion section rail 30 includes a main conversion section rail 301 and an auxiliary conversion section rail 302, and both the main conversion section rail 301 and the auxiliary conversion section rail 302 are electrically connected to the insulation monitoring device.

[0045] Optionally, in some optional embodiments of the present application, the insulation monitoring device monitors the insulation of the conversion section rail 30 to the ground using both AC and DC test voltages.

[0046] The embodiment of the present application also provides an orbital electrical monitoring system, which includes a potential monitoring device and the dual-system traction return rail provided in the first aspect of the embodiment of the present application. Among them, the potential monitoring device is used to monitor the potential difference between the dual-system traction return rail and the ground, and / or to monitor the potential difference between two sections of the dual-system traction return rail, and there is an insulating joint between the two sections of the rail. In this way, it is convenient for the operation personnel to judge the insulation situation between each section of the rail and to carry out later maintenance.

[0047] It should be explained that the two sections of the rail in the potential difference between the two sections of the rail can refer to any two of the DC section rail 10, the AC section rail 20, and the conversion section rail 30. In the case where the conversion section rail 30 includes the main conversion section rail 301 and the auxiliary conversion section rail 302, the two sections of the rail can refer to any two between the main conversion section rail 301, one or more auxiliary conversion section rails 302, the DC section rail 10, and the AC section rail 20.

[0048] In the case where the conversion section rail 30 includes the main conversion section rail 301 and the auxiliary conversion section rail 302, the auxiliary conversion section rail 302 is connected to the main conversion section rail 301 through an insulating joint, and at least one end of the main conversion section rail 301 is connected with the auxiliary conversion section rail 302. In some optional embodiments of the present application, the potential monitoring device is used to monitor the ground potential of the DC section rail 10, the AC section rail 20, the main conversion section rail 301, and the auxiliary conversion section rail 302.

[0049] Further, please refer to Figure 1 and Figure 2 , in some optional embodiments of the present application, the orbital electrical monitoring system further includes a waveform recording device, and the waveform recording device is electrically connected to the output end of the potential monitoring device. The waveform recording device is used to record the dynamic data of the output signal of the potential monitoring device. In this way, the waveform recording device can record the ground potential change curves of the DC section rail 10, the AC section rail 20, the main conversion section rail 301, and the auxiliary conversion section rail 30 during the process of the train passing through the conversion section rail 30, which helps the operation personnel to conduct analysis and research to judge the mutual insulation situation of each rail section. Optionally, in some optional embodiments of the present application, the waveform recording device is built into the rail potential monitoring device.

[0050] In some optional embodiments, please refer to Figure 1 and Figure 2, the rail potential monitoring device, the waveform recording device, and the insulation monitoring device can be integrated into the same box or cabinet to form the comprehensive rail potential and insulation monitoring device 60.

[0051] In some alternative embodiments of the present application, please refer to Figure 1 and Figure 2 , the track electrical monitoring system further includes a train sensing device 70. The train sensing device 70 starts and stops the rail potential monitoring device by detecting the passing condition of the train on the transition section rail 30. On this basis, in some alternative embodiments of the present application, the sensing module includes two train sensing devices 70. Along the parallel direction of the driving direction a, the two train sensing devices 70 are respectively arranged near both ends of the transition section rail 30. During the train running, one train sensing device 70 is used to judge whether the train enters the transition section rail 30, and the other train sensing device 70 is used to judge whether the train leaves the transition section rail 30. In such a structural form, when the train sensing device 70 at the front end detects a signal, the rail potential monitoring device starts and begins to record waveforms. When the train sensing device 70 at the end judges that the train leaves the transition section rail 30, the rail potential monitoring device closes and stops recording waveforms. On this basis, in some alternative embodiments of the present application, both sensing devices can judge whether the train enters the transition section rail 30 and whether it leaves the transition section rail 30.

[0052] There are various implementation manners of the train sensing device 70. It can be a phototube, a photomultiplier tube, a photoresistor, a photodiode, a phototransistor, an ultrasonic sensing module, a camera, etc. Optionally, in some embodiments, the train sensing device 70 is an industrial invisible light-controlled signal switch.

[0053] In some alternative embodiments, please refer to Figure 1 and Figure 2 , along the parallel direction of the driving direction a, both two train sensing devices 70 are arranged outside the transition section rail 30 and have a spacing from the transition section rail 30. In such a structural form, in the parallel direction of the driving direction a, the train sensing device 70 and the transition section rail 30 have a certain distance, so that before the train enters the transition section rail 30, the train sensing device 70 can detect a signal, and the rail potential monitoring device is immediately started to record waveforms. Optionally, in some embodiments, along the parallel direction of the driving direction a, the distance between the train sensing device 70 and the transition section rail 30 is 10 meters.

[0054] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A dual-current traction return rail, characterized in that, Comprising: DC-section rails, which are used to form a DC traction network with a DC catenary; AC-section rails, which are used to form an AC traction network with an AC catenary; A conversion-section rail, which is connected between the DC-section rail and the AC-section rail. Insulating joints are connected to both ends of the conversion-section rail, so that both the DC-section rail and the AC-section rail are insulated from the conversion-section rail. The length of the conversion-section rail is greater than or equal to the length of the train, and the conversion-section rail is arranged corresponding to the neutral section between the DC catenary and the AC catenary; The conversion-section rail includes a main conversion-section rail and an auxiliary conversion-section rail; the length of the main conversion-section rail is greater than or equal to the length of the train; the auxiliary conversion-section rail is connected to the main conversion-section rail through the insulating joint, and the auxiliary conversion-section rails are connected to both ends of the main conversion-section rail.

2. The dual-current traction return rail according to claim 1, characterized in that, The length of the auxiliary conversion-section rail is the standard rail length or half of the standard rail length.

3. The double-current traction return rail according to any one of claims 1 or 2, characterized in that The conversion-section rail is fixed by insulating fasteners; and / or, the conversion-section rail is supported on insulating sleepers.

4. An orbital electrical monitoring system, characterized in that, Comprising: The dual-system traction return rail according to any one of claims 1 to 3; An insulation monitoring device, which is used to monitor the insulation of the conversion-section rail to the ground.

5. The track electrical monitoring system according to claim 4, characterized in that, The insulation monitoring device monitors the insulation of the conversion-section rail to the ground by using two test voltages of AC and DC.

6. An orbital electrical monitoring system, characterized in that, Comprising: The dual-system traction return rail according to any one of claims 1 to 3; A rail potential monitoring device, which is used to monitor the potential difference between the dual-system traction return rail and the ground, and / or is used to monitor the potential difference between two sections of the dual-system traction return rail, and there is an insulating joint between the two sections of the rail.

7. The track electrical monitoring system according to claim 6, characterized in that, The conversion-section rail includes a main conversion-section rail and an auxiliary conversion-section rail. The auxiliary conversion-section rail is connected to the main conversion-section rail through an insulating joint, and at least one end of the main conversion-section rail is connected with the auxiliary conversion-section rail. The rail potential monitoring device is used to monitor the ground potential of the DC-section rail, the AC-section rail, the main conversion-section rail and the auxiliary conversion-section rail.

8. The track electrical monitoring system according to claim 6, wherein, It further includes a wave recording device, which is electrically connected to the output end of the rail potential monitoring device, and the wave recording device is used to record the dynamic data of the output signal of the rail potential monitoring device.

9. The track electrical monitoring system according to claim 8, characterized in that, It further includes a train sensing device, and the train sensing device starts and stops the wave recording device by detecting the train passing condition of the conversion-section rail.

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