Device for grounding the DC intermediate link

Abstract

A device for grounding a DC intermediate link connected to a converter on a rail vehicle is configured to be permanently arranged on the vehicle and includes two conductive members (23, 24) that are permanently connected to each pole of the DC intermediate link and to a first contact member (29, 30), each of the first contact members (29, 30) being movably arranged relative to a second contact member (35, 36), the second contact members (35, 36) being permanently connected to the grounded chassis part of the vehicle. A handle (34) is connected to the first or second contact member while being electrically insulated from the first or second contact member to be manually operated to move the contact member connected to the handle between a position where the DC intermediate link is not grounded and a position where the DC intermediate link is grounded.

Description

Field of the Invention

[0001] The present invention relates to a device for grounding a DC intermediate link connected to a converter on a rail vehicle. Although the present invention is particularly directed to railway vehicles, it actually also covers other types of rail vehicles, such as buses and trucks. Background Art

[0002] When maintenance is to be performed on such a converter or other components of the electrical system connected thereto, it is usually first controlled to separate the contactor to obtain zero voltage at the converter. However, for safety reasons, it is equally important to ground the DC intermediate link connected to the converter so that the voltage does not unexpectedly resume during the maintenance work.

[0003] So far, such grounding of the DC intermediate link connected to the converter has been performed by large and heavy equipment carried by a person (such as a grounding rod) in order to perform maintenance. This equipment is not only cumbersome to carry and manipulate, but also the safety provided thereby may not be as high as desired in some cases, especially because such laborious equipment may create an incentive to not manipulate the equipment strictly in the required manner.

[0004] Therefore, it is desirable to provide a device for grounding a DC intermediate link connected to a converter on a rail vehicle, which is easy to manipulate and improves the safety of an individual approaching such a converter during maintenance relative to such known devices. Summary of the Invention

[0005] It is an object of the present invention to provide a device of the type defined in the preamble, which is improved at least in some respects relative to such known devices.

[0006] This object is achieved by providing the device of the present application.

[0007] Therefore, the device is configured to be permanently arranged on a rail vehicle, which means that it does not have to be carried around and taken to its place of use, but it is ensured that it can be used at any time on the rail vehicle. The device has two conductive members, the two conductive members being configured to have one end permanently connected to each pole of the DC intermediate link and the other end connected to a first contact member, each of the first contact members being configured to be movably arranged relative to a second contact member, the second contact member being permanently connected to the grounded chassis part of the vehicle. The first contact member can move between an open position in which the DC intermediate link is not grounded and a contact closed position in which the DC intermediate link is grounded relative to the second contact member. In addition, a handle is connected to the first or second contact member while being electrically insulated from the first or second contact member to be manually operated to move the contact member connected to the handle between a position in which the DC intermediate link is not grounded and a position in which the DC intermediate link is grounded.

[0008] Therefore, the device is permanently in the position where it is to be used, and also permanently connects the first contact member to the pole of the DC intermediate link to be grounded, so that the grounding of the DC intermediate link of the converter in question can be easily and reliably obtained by simply manually operating the handle connected to the first or second contact member, which can be carried out without exposing the maintenance operator to any type of danger.

[0009] Preferably, this type of separate device is arranged for all converters (such as line converters and motor converters) on the rail vehicle, which enables the maintenance operator to determine that the DC intermediate link of a specific converter is grounded independently of the rest of the system.

[0010] According to an embodiment of the present invention, the device includes a bracket, two contact members connected to the handle are arranged on the bracket, and the bracket can be guided to move along a member fixed relative to the chassis part. Thus, by operating the handle, the contact member connected to the handle can be comfortably brought into contact with another contact member and the state in which the DC intermediate link is grounded. The member fixed relative to the chassis part does not have to be fixed to the chassis part, but only has to be immovable relative to the chassis part.

[0011] According to another embodiment of the present invention, the bracket at least has a part made of insulating material, the part connecting the bracket and thus the contact members arranged on the bracket to the handle.

[0012] According to another embodiment of the invention, the first contact member is a plate-shaped metal member, and according to a further development of this embodiment, the second contact member is configured to bear against a large surface of the first contact member under prestress in the closed position, which ensures that once the grounded state is obtained, the grounded state is reliably maintained.

[0013] According to another embodiment of the invention, each of the second contact members forms a clamping jaw, which is configured to receive the first contact member while bearing against the first contact member under prestress from opposite directions in the closed position. Thereby, a reliable contact formed between the first and second contact members is ensured in the closed position and thereby the grounding of the DC intermediate link is ensured.

[0014] According to another embodiment of the invention, the device is configured to be arranged inside a converter housing, wherein the handle is accessible for operation in the case where the front cover of the housing is removed to expose an opening into the housing. Thereby, when not needed, the handle will not inadvertently move to the grounded position, because the front cover of the converter housing must be removed to operate the handle, and the front cover of the converter housing is only removed when the maintenance operator actually wants to perform maintenance work.

[0015] According to another embodiment of the invention, the handle is configured to be pulled out of the housing to obtain the contact closed position and to be pushed into the housing to obtain the open position. This ensures that when the front cover is in place, the device does not ground the DC intermediate link, because applying the front cover to the housing requires pushing the handle into the housing and thereby forming the open position of the contact members of the device.

[0016] According to another embodiment of the invention, the front cover is in a position closing the opening of the housing, and this position is configured to hold the handle in a position corresponding to a position of the contact members that does not ground the DC intermediate link. This ensures that as long as the front cover closes the housing opening, the grounding device is always in a neutral non-grounded position.

[0017] According to another embodiment of the invention, the device includes a mechanism for locking the handle with the first and second contact members in the closed position. This ensures that the maintenance operator or anyone else will not inadvertently move the handle and cause the non-grounded position of the device when working on the converter in question.

[0018] According to another embodiment of the invention, the mechanism is configured to lock the handle and the first and second contact members in the closed position at a position of the handle that prevents the front cover from closing the converter housing opening. This ensures that the front cover is not put in place as long as the DC intermediate link is grounded.

[0019] According to another embodiment of the invention, the conductive member is flexible, which simplifies the formation of the device with the intended performance of the invention. The conductive member is therefore preferably a power cable.

[0020] The invention also relates to a method for grounding a DC intermediate link connected to a converter on a rail vehicle, characterized in that the device according to the invention is used and the following steps are performed: opening the front cover of the converter housing containing the converter and the DC intermediate link, and pulling out the handle through the housing opening previously covered by the front cover to a position where the first contact member and the second contact member are in contact with each other, thereby grounding the DC intermediate link. This way of obtaining the grounding will prevent the front cover from being inadvertently closed.

[0021] According to an embodiment of the invention, the method further comprises the step of locking the handle in the pulled-out position to prevent the handle from being inadvertently pushed into the housing to a position corresponding to a position where the DC intermediate link is not grounded.

[0022] The invention also relates to a rail vehicle, wherein at least one, preferably all, of the converters on the rail vehicle have the device according to the invention for grounding a DC intermediate link connected to the converter.

[0023] Additional advantages and advantageous features of the invention will become apparent from the following description. Description of the Drawings

[0024] With reference to the accompanying drawings, the following is a detailed description of embodiments of the invention cited by way of example.

[0025] In the figures:

[0026] Figure 1 is a very schematic view showing how different types of converters can be arranged in a rail vehicle,

[0027] Figure 2 is a perspective view of a device according to an embodiment of the invention, wherein the device is in a position where the DC intermediate link connected to the converter is not grounded,

[0028] Figure 3 is Figure 2Perspective view of the device shown in the figure, where the device is in a position to ground the DC intermediate link connected to the converter,

[0029] Figure 4 To show a view of the converter housing containing an arrangement according to Figure 2 and 3 where the front cover has been removed from the housing and the device is in a position where the DC intermediate link is not grounded, and

[0030] Figure 5 To show a view corresponding to Figure 4 where the handle of the device has been pulled out through the housing opening and the device is in a position to ground the DC intermediate link. Detailed Description

[0031] Figure 1 Schematically shows how power can be supplied from the AC power line 2 to the rail vehicle 1 and used in the vehicle. The vehicle is configured to move along the AC power line 2, which thus acts as an AC power source and can carry, for example, a single-phase AC voltage of 15 kV and 16 2 / 3 Hz (Sweden, Germany, etc.) or 25 kV and 50 Hz (Denmark, China, India, etc.). The vehicle has a transformer 3 for transforming the voltage from the power line 2 to a suitable level. Here, the transformer has two secondary windings 4, 5 connected to line converters 6, 7, each of which is used to transfer a DC voltage of, for example, 0.8 - 3 kV at its output. Thus, this DC voltage exists between the poles 8, 9 and 10, 11 of the DC intermediate links 12 and 13 respectively. These DC intermediate links are connected to the input terminals of the motor converters 14, 15, each of which is controlled to transfer a three-phase AC voltage at its output to the motors 16, 17 for the propulsion of the vehicle. Power can be transferred from the corresponding DC intermediate link to the auxiliary converter in a corresponding manner, and the auxiliary converter is used to supply power to sockets arranged in the rail vehicle (such as connections for computers), as well as to lighting, heating, and other appliances.

[0032] Schematically shows how the arrangements 18, 19 for grounding the respective DC intermediate links 12, 13 are arranged in connection with the respective DC intermediate links 12, 13.

[0033] Figure 2 Shows such a device according to an embodiment of the present invention. The device has a frame with a bracket 20 for fixing the device to the frame 21 of the converter housing 22 (see Figure 4) The converter housing 22 includes a converter, electronic devices associated with the control of the converter, and in addition a DC intermediate link connected to the converter.

[0034] The device has two conductive members 23, 24 in the form of power cables, which are configured to have one end 25, 26 connected to each pole of the DC intermediate link and the other end 27, 28 connected to respective first contact members 29, 30 in the form of metal plates. The first contact members 29, 30 are arranged on a carriage 31, which is movably guided along a member 32, and the member 32 is fixed relative to the chassis part of the vehicle by a bracket 20. The carriage 31 has at least a part 33 made of insulating material, and the part 33 connects the carriage and thus the first contact members 29, 30 to a handle 34.

[0035] The device further includes second contact members 35, 36, which are permanently connected to the grounded chassis part of the vehicle through a grounding member 37.

[0036] The first contact members 29, 30 can move relative to the second contact members 35, 36 between Figure 2 an open position shown in which the DC intermediate link is not grounded and Figure 3 a contact closed position shown in which the DC intermediate link is grounded. The second contact members 35, 36 are designed as jaws, which are configured to receive the first contact members while being supported against the first contact members under pre-tension in opposite directions in the Figure 3 closed position shown.

[0037] When maintenance work is to be carried out in the converter housing, the isolation contactor is controlled to obtain zero voltage between the poles of the DC intermediate link. However, this voltage will actually be a voltage different from zero (such as 24V) that still exists in some cases. Then, the front cover is removed from the converter housing 22 to expose the handle 34 of the device, as Figure 4 shown. It shows how the front cover pushes the handle into the housing to ensure that the device is in a non-grounded state when the front cover is in place.

[0038] Then, the maintenance operator holds the handle 34 and pulls the handle 34 out of the housing opening 38 to the Figure 5 position shown, in which the first contact members 29, 30 have contacted the second contact members 35, 36, and thus the poles of the DC intermediate link have contacted the chassis part of the vehicle to ground the DC intermediate link.

[0039] In Figure 5It shows how the handle 34 has through holes 39, 40 so that a lock can be applied to the handle, thereby ensuring that the DC intermediate link ground is maintained after obtaining the ground of the DC intermediate link by preventing the handle from being inadvertently pushed into the converter housing 22.

[0040] Of course, the present invention is in no way limited to the above embodiments, because for those skilled in the art, many possibilities for modifying the present invention may be obvious without departing from the scope of the present invention as defined in the appended claims.

[0041] The handle can be connected to a second contact member and thus be movable to move the contact members relative to each other between the open position where the DC intermediate link is not grounded and the contact closed position where the DC intermediate link is grounded. Then, the second contact member can be permanently connected to the grounded chassis portion through a conductive member such as a flexible power cable.

[0042] Figure 1 The present invention is shown, and the present invention is applicable to grounding the DC intermediate link of a converter connected to a rail vehicle fed by an AC power supply line. However, the grounding device according to the present invention can also be used for DC applications such as having a DC power supply of 750 VDC or 1500 VDC.

[0043] Auxiliary contacts (not shown in the drawings) inside the grounding device are configured to detect the position of the grounding device, and the information thus provided can be used to monitor the position of the grounding device and to interlock the upstream power contacts to be energized and connect the voltage to the DC intermediate link.

Claims

1. A device for grounding the DC intermediate links (12, 13) of converters (6, 7, 14, 15) connected to a rail vehicle (1), characterized in that, the device is configured to be permanently arranged on the rail vehicle and comprises: ● two conductive members (23, 24), the two conductive members (23, 24) being configured to have one end (25, 26) permanently connected to each pole (8 - 11) of the DC intermediate link and the other end (27, 28) connected to a first contact member (29, 30), ● first contact members (29, 30), each configured to be movably arranged relative to a second contact member (35, 36), ● second contact members (35, 36), permanently connected to the grounded chassis part of the rail vehicle, wherein the first contact members (29, 30) can move relative to the second contact members (35, 36) between an open position in which the DC intermediate links (12, 13) are not grounded and a contact - closed position in which the DC intermediate links are grounded, and ● a handle (34), the handle (34) being connected to the first contact member while being electrically insulated from the first contact member, to be manually operated to move the first contact member connected to the handle (34) between a position in which the DC intermediate links are not grounded and a position in which the DC intermediate links are grounded, wherein the device comprises a bracket (31), both of the first contact members connected to the handle (34) are arranged on the bracket (31), and the bracket (31) can be guided to move along a member (32) fixed relative to the chassis part, and the bracket (31) has at least a part (33) made of insulating material, the part (33) connecting the bracket and thus the first contact members (29, 30) arranged on the bracket to the handle (34).

2. A device for grounding the DC intermediate links (12, 13) of converters (6, 7, 14, 15) connected to a rail vehicle (1), characterized in that, the device is configured to be permanently arranged on the rail vehicle and comprises: ● two conductive members (23, 24), the two conductive members (23, 24) being configured to have one end (25, 26) permanently connected to each pole (8 - 11) of the DC intermediate link and the other end (27, 28) connected to a first contact member (29, 30), ● first contact members (29, 30), each configured to be movably arranged relative to a second contact member (35, 36), ● second contact members (35, 36), permanently connected to the grounded chassis part of the rail vehicle, wherein the first contact members (29, 30) can move relative to the second contact members (35, 36) between an open position in which the DC intermediate links (12, 13) are not grounded and a contact - closed position in which the DC intermediate links are grounded, and ● A handle (34) that is connected to the second contact member while being electrically insulated from the second contact member and is manually operable to move the second contact member connected to the handle (34) between a position where the DC intermediate link is not grounded and a position where the DC intermediate link is grounded.

3. The device according to claim 2, wherein, the device includes a bracket (31), both of the two second contact members (35, 36) connected to the handle (34) are arranged on the bracket (31), and the bracket (31) is movably guided along a member (32) fixed relative to the chassis portion.

4. The device according to claim 3, wherein, the bracket (31) has at least a portion (33) made of an insulating material, and the portion (33) connects the bracket and thus the second contact members (35, 36) arranged on the bracket to the handle (34).

5. The device according to any one of claims 1 - 4, wherein, the first contact members (29, 30) are plate - shaped metal members.

6. The device according to claim 5, wherein, the second contact members (35, 36) are configured to be supported against a large surface of the first contact members (29, 30) under a pre - tension in the contact - closed position.

7. The device according to claim 6, wherein, each of the second contact members (35, 36) forms a jaw that is configured to receive the first contact members (29, 30) and support against the first contact members under a pre - tension from opposite directions in the contact - closed position.

8. The device according to claim 1 or 2, wherein, the device is configured to be arranged inside a converter housing (22), and the handle (34) can be accessed for operation when the front cover of the converter housing is removed to expose an opening (38) into the converter housing.

9. The device according to claim 8, wherein, the handle (34) is configured to be pulled out from the converter housing (22) to obtain the contact - closed position and pushed into the converter housing to obtain the open position.

10. The device according to claim 8 or 9, wherein, the position of the front cover that closes the opening (38) of the converter housing is configured to hold the handle (34) in a position corresponding to the position where the DC intermediate link is not grounded by the first and second contact members.

11. The device according to claim 10, wherein, the device includes mechanisms (39, 40) for locking the handle (34) with the first contact members (29, 30) and the second contact members (35, 36) in the contact - closed position.

12. The device according to claim 11, wherein, The mechanism (39, 40) is configured to lock the handle (34) with the first contact member (29, 30) and the second contact member (35, 36) in the contact closed position at a position of the handle (34) that prevents the front cover from closing the opening (38) of the converter housing.

13. The device according to claim 1 or 2, characterized in that the conductive member (23, 24) is flexible.

14. The device according to claim 13, characterized in that the conductive member (23, 24) is a power cable.

15. A method for grounding a DC intermediate link (12, 13) connected to a converter (6, 7, 14, 15) on a rail vehicle (1), characterized in that using the device according to any one of claims 1-14 and performing the following steps: ● Opening the front cover of the converter housing (22) containing the converter and the DC intermediate link, and ● Pulling out the handle (34) through the opening (38) of the converter housing previously covered by the front cover to a pulled-out position where the first contact member (29, 30) and the second contact member (35, 36) are in contact with each other, thereby grounding the DC intermediate link (12, 13).

16. The method according to claim 15, characterized in that the method further includes the step of locking the handle (34) in the pulled-out position to prevent the handle (34) from being inadvertently pushed into the converter housing (22) to a position corresponding to not grounding the DC intermediate link (12, 13).

17. A rail vehicle having at least one converter thereon with the device according to any one of claims 1-14 for grounding a DC intermediate link (12, 13) connected to the converter (6, 7, 14, 15).

18. The rail vehicle according to claim 17, characterized in that all converters on the rail vehicle have the device.

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