Switching device

Abstract

The invention relates to a switching device (2) having a commutation current path (4), a first isolation section (6) and a second isolation section (8). In this case, the first isolation section (6) and the second isolation section (8) form a series circuit arranged in parallel with the commutation current path (4). The second isolating section (8) has a first contact part (12), a second contact part (14) and a third contact part (16), the first contact part (12) being designed as a movable contact part. The first contact part (12) is supported so as to be movable along the switching axis (24) from a first contact position (18) in electrical contact with the second contact part (14) to a second contact position (20) in electrical contact with the third contact part (16). In the second contact position (20), a mechanical contact force (52) acts in the radial direction between the first contact part (12) and the third contact part (16).

Description

Technical Field

[0001] The invention relates to a switching device having a commutation current path. Background Art

[0002] In circuits, especially those used for supplying energy at medium or high voltage, short circuits can occur in the event of insulation failure or for other reasons. Short circuits cause large currents to flow, which can damage or destroy the operating facilities in the energy supply network. Due to the expansion of decentralized feeders, short-circuit currents can increase to a level that exceeds the rating of existing operating facilities.

[0003] One possibility for preventing inadmissibly high short-circuit currents is to use a current-limiting device, for example a fast-acting fuse, as a short-circuit current limiter.

[0004] The principle of these devices is to quickly disconnect the short-circuit current in the event of a short circuit. This is achieved by a disconnection function. For normal operation, there is a nominal current path, which can be disconnected in the event of a short circuit. In parallel with the nominal current path is another current path (commutation current path, parallel path) which has a fuse that disconnects the short-circuit current.

[0005] In the event of a short circuit, the nominal current path is disconnected, resulting in an arc. The arc voltage causes the current to commutate completely into the parallel path. The fuse is then triggered, extinguishing the arc. The impedances of the parallel current path and the nominal current path must be matched to each other to enable commutation of the short-circuit current. In addition, the current through the fuse in normal operation should not be too large to prevent the fuse from triggering prematurely.

[0006] This results in the following conflict of objectives: in nominal operation, the parallel current path should have the highest possible impedance in order not to overload the fuse, whereas in the event of a short circuit, the parallel current path should have the lowest possible impedance in order to enable the current to be commutated into the parallel current path. In order to support the commutation of the current from the nominal current path into the parallel current path, a high arc burning voltage is advantageous, which occurs in particular in the event of a sudden opening of the nominal current path, and which is used in the prior art.

[0007] At the moment when the contacts separate after the last metal bridge has melted, an arc is generated, the burning voltage of which is actually determined only by the material properties of the contacts and is formed by the voltage drop at the cathode and anode. Increasing the arc burning voltage by prolonging the arc is ineffective here, because the commutation process is already completed at a very small contact distance. For typical contact materials, the arc burning voltage is only about 20V. This voltage is too low to commutate higher currents into the parallel path in practical applications, which is why the conventional isolating segment, which is originally advantageous because it can be reused compared to the nominal current path of the sudden opening, is not suitable for fault current limiters.

[0008] A switching device with two isolating sections connected electrically in series is known from the publication DE 10 2020 205 784 A1. The publication discloses a switching device having a commutation current path, a first isolating section and a second isolating section, wherein the first isolating section and the second isolating section form a series circuit arranged in parallel with the commutation current path, wherein the second isolating section has a first contact, a second contact and a third contact, wherein the first contact is designed as a movable contact, and wherein the first contact is supported to be movable from a first contact position in electrical contact with the second contact to a second contact position in electrical contact with the third contact, the second contact and the third contact being at electrical potential, and the first contact being supported to be movable along a switching axis.

[0009] This known switching device must function relatively precisely, in particular with regard to the position of the third contact section and the movement of the first contact section from the first contact position to the second contact position, in order to be able to reliably close the second isolating segment in the second contact position. Summary of the invention

[0010] The object of the present invention is to provide a switching device and a method which can be produced cost-effectively.

[0011] According to the invention, this object is achieved by a switching device and a method according to the independent patent claims. Advantageous embodiments are given in the dependent patent claims.

[0012] A switching device is disclosed, which has a commutation current path, a first isolating segment and a second isolating segment, wherein the first isolating segment and the second isolating segment form a series circuit arranged in parallel with the commutation current path, wherein the second isolating segment has a first contact portion, a second contact portion and a third contact portion, wherein the first contact portion is designed to be a movable contact portion, and wherein the first contact portion is supported to be able to move from a first contact position in electrical contact with the second contact portion to a second contact position in electrical contact with the third contact portion, the second contact portion and the third contact portion are at an electrical potential, that is, at the same electrical potential, and the first contact portion is supported to be able to move along a switch axis (translation), wherein, in the second contact position, a mechanical contact force acts between the first contact portion and the third contact portion in a radial direction (relative to the switch axis).

[0013] In other words, the contact force acts perpendicularly to the direction of movement of the first contact part. The contact force therefore acts perpendicularly to the switching direction or the switch axis. As a result, there is advantageously no rebound between the first contact part and the third contact part when closing. Furthermore, since the radial contact force can be achieved independently of the axial position of the third contact part, high precision requirements regarding the axial position of the third contact part do not need to be met when manufacturing the switch device.

[0014] The switching device can be designed in such a way that the third contact portion is a clamping contact portion and the contact force is a (radially acting) clamping force.

[0015] Such a clamping force can certainly allow axial movement between the first contact portion and the third contact portion. Preferably, the clamping force can act on the first contact portion in a braking manner. In particular, the clamping force can brake the first contact portion so that it stops at the second electrical contact position.

[0016] The switching device can be designed in such a way that the third contact has elastic (especially radially elastic) contact elements. These elastic contact elements can advantageously achieve a clamping effect; therefore, they can also be referred to as elastic clamping elements.

[0017] The switching device can be designed such that the third contact portion has a recess which at least partially receives the first contact portion in the second contact position.

[0018] Therefore, in the second contact position, at least a portion of the first contact portion is arranged in the recess. In other words, the first contact portion and the third contact portion are designed so that when moving from the first contact position to the second contact position, at least a portion of the first contact portion enters the recess. This enables a compact design of the switch device.

[0019] The switching device can be designed in such a way that the recess (in the direction of the switching axis) is substantially hollow cylindrical. Such a recess can be manufactured relatively easily.

[0020] The switch device can also be designed in such a way that the recess and / or the first contact portion (in the direction of the switch axis) are conical, thereby advantageously achieving a clamping effect between the third contact portion having the recess and the first contact portion.

[0021] The switch device can be designed in such a way that the second isolating section is a gas isolating section. The gas isolating section has a relatively high arc voltage when it is disconnected. This allows a relatively high commutation voltage to be achieved. This causes the current to be commutated quickly into the commutation current path.

[0022] The switching device can be designed in such a way that the second contact portion and the third contact portion of the second isolating segment are elastically supported in the direction of the switching axis.

[0023] This has the advantage that, in particular in the first contact position, a sufficient contact pressure can be achieved which contributes to a stronger electrical contact.

[0024] The switching device can be designed in such a way that during a switching process an intermediate state exists in which the contacts of the first isolating section are arranged without electrical contact with one another and the contacts of the second isolating section are arranged without electrical contact with one another.

[0025] The switching device can be designed such that in the intermediate state a switching arc occurs between the contacts of the first isolating section and a switching arc occurs between the contacts of the second isolating section.

[0026] Therefore, during the switching process, a switching arc occurs between the contacts of the first isolating segment and between the contacts of the second isolating segment, respectively, so that a higher arc voltage is present in the current path with two isolating segments, also referred to as the nominal current path. The high arc voltage causes the flowing current to be reliably commutated from the nominal current path to the commutation current path.

[0027] The switching device can be designed in such a way that a switching arc of the second isolating section occurs between the first contact portion and the second contact portion.

[0028] The second isolating section having a total of three contacts is preferably designed in such a way that a switching arc is present between the first contact and the second contact during a switching process.

[0029] The switch device can be designed in such a way that the commutation current path has a fuse and / or a semiconductor element. Such a semiconductor element can be, for example, an IGBT, a transistor, a diode or a MOSFET. In particular, due to the large currents commutated into the commutation current path, the fuse can be blown within a few milliseconds, thereby interrupting the current very quickly.

[0030] The switch device can be designed as follows: the first isolating section has a fixed contact part and a movable contact part, the movable contact part is supported to be able to move translationally along the switch axis, and when the first isolating section is closed, a mechanical contact force acts between the movable contact part and the fixed contact part in an axial direction (relative to the switch axis). The fixed contact part can be elastically supported. The movable contact part is in particular a contact part driven by a driver.

[0031] The switching device can be designed in such a way that the first isolating section is a vacuum isolating section.

[0032] The switching device can be designed in such a way that the first isolating section is designed as a vacuum switching tube.

[0033] Compared to gaseous isolating sections, vacuum isolating sections, more precisely vacuum interrupters, have the advantage that sufficient isolation can be established with a relatively short contact path (and thus within a short time).

[0034] Furthermore, a method for switching current by means of a switch device according to any of the above variants is disclosed, wherein in the second contact position, a mechanical contact force is generated between the first contact portion and the third contact portion of the second isolating segment in a radial direction (relative to the switch axis).

[0035] The switching device and method have the same or similar properties and / or advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention will be described in more detail below by way of embodiments. Here, the same reference numerals represent the same elements or elements having the same function.

[0037] Figure 1 An embodiment of a switch device is shown in which a commutation current path is in a closed state;

[0038] Figure 2 The switching device is shown in an intermediate state of partially open state with a switching arc;

[0039] Figure 3 The switch device is shown in an open state; and

[0040] Figure 4 An embodiment is shown in which the third contact portion has a tapered recess. DETAILED DESCRIPTION

[0041] Figure 1 An embodiment of a switching device 2 with a nominal current path 3 and a commutation current path 4 is shown. In this case, the nominal current path 3 passes through at least two isolating segments, namely a first isolating segment 6 and a second isolating segment 8. In the present example, a fuse 36 is arranged in the commutation current path 4. In principle, however, (in particular fast-switching) semiconductor elements (semiconductor switching elements) can also be arranged in the commutation current path 4 to interrupt the current flow in the commutation current path 4. Optionally, further electrical elements can be arranged in parallel with the commutation current path 4, more precisely in parallel with the fuse 36 or the semiconductor element.

[0042] The first isolating section 6, which is designed in this case as a vacuum interrupter 10, has the following properties: Compared with conventional gas isolating sections, the vacuum interrupter 10 can produce high isolation with a very short switching stroke, which can also be achieved in a shorter time with conventional drives 38 compared with longer switching strokes. For the same isolation performance, a comparable gas isolating section must have a significantly longer stroke, which is why the switch-off time of such a switching device is longer than when using a vacuum interrupter 10.

[0043] The second isolating section 8, which is designed as a gas isolating section 22 in this example, has three contacts. Here, the first contact 12 is designed as a movable contact. The first contact 12 is supported so that it can be moved translationally along the switching axis 24 by a drive 38, which also enables the movement of the first isolating section. The first isolating section 6 and the second isolating section 8 are designed rotationally symmetrically with respect to the switching axis 24; therefore, the switching axis 24 is also an axis of symmetry.

[0044] The drive drives the switching rod 39 in translation. This causes a translational drive movement 37. In the exemplary embodiment, the drive 38 is designed such that it advantageously drives both the first isolating segment 6 and the second isolating segment 8. In principle, however, two independent drives can also be used in other switching devices.

[0045] The first contact portion 12 of the second isolation section 8, i.e., the gas isolation section 22, can move back and forth between the second contact portion 14 and the third contact portion 16. Figure 1 In the closed state of the switching device 2, the first contact portion 12 is in contact with the second contact portion 14. Here, in the closed state, this means that the fixed contact portion 32 and the movable contact portion 34 of the first isolating segment 6, that is, the vacuum interrupter 10, are in electrical contact, so that the nominal current path 3 is closed. In the closed state of the switching device 2, the electrical contact pair between the first contact portion 12 and the second contact portion 14 of the second isolating segment 8 also has electrical contact for the nominal current path 3 to pass through. Figure 1 In the closed state of the switching device 2, a first mechanical contact force 48 occurs between the fixed contact portion 32 and the movable contact portion 34 of the first isolating segment 6, which acts or extends in the axial direction (relative to the switch axis 24). The first contact force causes the first isolating segment 6 to be reliably closed. The first contact force 48 is generated by the drive 38. The spring 44 of the first isolating segment 6 improves the contact. In particular, the spring 44 causes a sufficient contact pressure to be achieved, which contributes to a stronger electrical contact.

[0046] In accordance with Figure 1 In the closed state of the switching device 2, a second mechanical contact force 50 occurs between the first contact portion 12 and the second contact portion 14 of the second isolating segment 8, which acts or extends in the axial direction (relative to the switch axis 24). The second contact force 50 causes the second isolating segment 8 to be reliably closed in the first contact position 18. The second contact force 50 is generated by the drive 38. The spring 40 of the second isolating segment 8 improves the contact. In particular, the spring 40 causes a sufficient contact pressure to be achieved, which contributes to a stronger electrical contact.

[0047] Figure 2 An intermediate state 26 of the switching device 2 is shown, which occurs during the opening movement of the switching device 2. The translational opening movement is effected by the drive 38 along the switching axis 24. In the intermediate state 26, the first contact 12 of the second isolating segment 8 is located between the second contact 14 and the third contact 16. The intermediate state 26 is a dynamic state which ends according to Figure 3 status.

[0048] Figure 3The open state of the switching device 2 is shown. The first isolating section 6 is open. The second isolating section 8 is in the second electrical contact position 20. The second electrical contact position 20 occurs between the first contact 12 and the third contact 16. Here, the first contact 12 of the second isolating section 8 rests on the third contact 16. The second contact 14 and the third contact 16 are at the same potential and are connected to the node of the nominal current path 3. This means that, in the open and closed state of the switching device 2, the moving first contact 12 of the second isolating section 8 is at the same potential as the second contact 14 and the third contact 16. Therefore, the second isolating section 8 is also closed in the second contact position 20. This has the advantage that the first contact 12 (and the moving contact 34) are at a defined potential.

[0049] In the open state of the switching device 2, i.e. when the second isolating segment 8 is in the second contact position 20, a third mechanical contact force 52 occurs in the radial direction (relative to the switch axis 24) between the first contact portion 12 and the third contact portion 16. As a result, advantageously, no rebound occurs between the first contact portion 12 and the third contact portion 16 during closing. In addition, in the manufacture of the switching device, no special precision requirements need to be met for the axial position of the third contact portion 16.

[0050] In the embodiment, the third contact portion 16 is a clamping contact portion; the third contact force 52 is a (radially acting) clamping force. In order to generate the third contact force 52, the third contact portion 16 has an elastic contact element 56. The elastic contact element 56 can be, for example, an elastic contact plate. In this case, the contact element 56 can be elastic in the radial direction.

[0051] The third contact portion 16 has a recess 54. Figure 3 In the second contact position 20 shown, the recess 54 receives a part of the first contact 12. This allows a compact design of the switching device 2. The recess 54 can be designed in different ways.

[0052] according to Figure 2 The significance of the intermediate state 26 is that in the first isolating section 6, i.e. in the vacuum interrupter 10, and in the second isolating section 8, i.e. in the gas isolating section 22, switching arcs 28, 30 are formed between the contacts respectively. Here, the arc 28 is formed between the fixed contact 32 (first contact 32) and the movable contact 34 (second contact 34) of the vacuum interrupter 10. The switching arc 30 is formed between the first contact 12 and the second contact 14 of the gas isolating section 22 respectively. The difference between the two switching arcs 28 and 30 lies in the level of the voltage drop therein, i.e. the arc voltage. In the embodiment, the arc voltage U in the switching arc 30 in the gas isolating section 22 is 2.5 V. libo2 Higher than the arc voltage U in the switching arc 28 in the vacuum interrupter 10libo1 This is because the gas molecules are ionized in the gas isolation section 22, which results in a higher applied voltage. A vacuum exists in the vacuum switching tube 10, which results in a lower arc voltage. In general, the arc voltage U in the switching arc 30 in the gas isolation section 22 is libo2 At least equal to (or greater than) the arc voltage U in the switching arc 28 in the vacuum switching tube 10 libo1 .

[0053] Higher arc voltage U in the gas-insulated section 22 libo2 This leads to improved current commutation from the nominal current path 3 to the commutation current path 4, thereby ensuring reliable commutation into the commutation current path 4. If only vacuum switching tubes 10 are used in the nominal current path 3, there is a conflict of objectives between the highest possible impedance of the commutation current path 4 for normal operation and the lowest possible impedance of the commutation current path 4 for short circuits. By means of the gas isolation section 22 having the structure described, current can be commutated into the commutation current path 4 even in the case of a high impedance of the commutation current path 4, thereby reducing the risk of accidental triggering of the fuse 36 during normal operation.

[0054] In order to ensure that a certain contact pressure exists in both the first isolating segment 6 and the second isolating segment 8, the contact systems of the two isolating segments 6, 8 are advantageously supported elastically. Figures 1 to 3 The spring is shown in different deformations. Figure 1 In the case of Figure 2 In the process, the spring 44 is deformed so that one end thereof moves toward the stopper 46. Figure 3 In the embodiment, the end of the spring 44 abuts against the stop 46. The elastic support of the contact portion causes the first contact portion 32, which is basically designed as a fixed contact portion 32, to be pressed against the movable second contact portion 34 by the spring 44 in the closed state, and the second contact portion is effectively connected to the drive 38.

[0055] The first contact portion 14 and the second contact portion 16 of the gas separation section 22 are hereby Figures 1 to 3 The support is also elastically supported in a translational manner along the switching axis 24. For this purpose, a spring 40 is provided, which is arranged according to Figure 1 The second isolating segment 8 is loaded in the closed state. Figure 2 In the intermediate state, the spring 40 is deformed so that one end thereof moves toward the stopper 42. Figure 3 In the disconnected state, the end of the spring 40 is against the stop 42. At this time, the first contact portion 12 and the third contact portion 16 are in electrical contact.

[0056] exist Figures 1 to 3In the embodiment shown in FIG. 2 , the recess 54 of the third contact 16 is substantially hollow-cylindrical in the direction of the switching axis 24 .

[0057] Figure 4 An embodiment is shown in which the recess 54 of the third contact 16 is substantially conical in the direction of the switch axis 24. For ease of viewing, the cone in the figures is shown exaggerated.

[0058] Alternatively, the first contact 12 may also be tapered in the direction of the switch axis 24 . In particular, the portion of the first contact 12 which is received by the recess 54 of the third contact 16 in the second contact position 20 may be tapered in the direction of the switch axis 24 .

[0059] A switching device which can be produced cost-effectively is described and which advantageously does not spring back when reaching its open switching position.

[0060] Reference numerals list

[0061] 2 Switchgear

[0062] 3 Nominal current path

[0063] 4 Commutation current path

[0064] 6 First isolation section

[0065] 8 Second isolation section

[0066] 10 Vacuum switch tube

[0067] 12 First contact

[0068] 14 Second contact part

[0069] 16 Third contact part

[0070] 18 First contact position

[0071] 20 Second contact position

[0072] 22 Gas isolation section

[0073] 24 Switch axis

[0074] 26 Intermediate state

[0075] 28 Switching arc in the first isolation section

[0076] 30 Switching arc in the second isolation section

[0077] 32 Fixed contact portion of the first isolation segment

[0078] 34 Moving contact portion of the first isolation segment

[0079] 36 Fuse safety device

[0080] 37 Drive Motion

[0081] 38 Driver

[0082] 39 Switch lever

[0083] 40 Spring of the second isolation section

[0084] 42 The stopper of the spring of the second isolation section

[0085] 44 Spring of the first isolation section

[0086] 46 The spring stop of the first isolation section

[0087] 48 First contact force

[0088] 50 Second contact force

[0089] 52 Third contact force

[0090] 54 recess

[0091] 56 Elastic contact element

[0092] U libo1 Arc voltage of the switching arc in the first isolation section

[0093] U libo2 Arc voltage of the switching arc of the second isolation segment.

Claims

1. A switching device (2), comprising a commutation current path (4), a first isolating section (6) and a second isolating section (8), wherein: The first isolating section (6) and the second isolating section (8) form a series circuit arranged in parallel with the commutation current path (4), wherein the second isolating section (8) has a first contact portion (12), a second contact portion (14) and a third contact portion (16), wherein the first contact portion (12) is designed as a movable contact portion, and wherein the first contact portion (12) is supported to be movable along a switching axis (24) from a first contact position (18) in electrical contact with the second contact portion (14) to a second contact position (20) in electrical contact with the third contact portion (16), and the second contact portion (14) and the third contact portion (16) are at an electrical potential, The invention is characterized in that, in the second contact position (20), a mechanical contact force (52) acts between the first contact portion (12) and the third contact portion (16) in a radial direction.

2. The switch device according to claim 1, characterized in that: The third contact portion (16) is a clamping contact portion, and the contact force (52) is a clamping force.

3. The switch device according to claim 1 or 2, characterized in that: The third contact portion (16) has a resilient contact element (56).

4. A switching device according to any one of the preceding claims, characterized in that The third contact portion (16) has a recess (54) which at least partially receives the first contact portion (12) in the second contact position (20).

5. The switch device according to claim 4, characterized in that: The recess (54) is substantially in the shape of a hollow cylinder.

6. The switch device according to claim 4, characterized in that: The recess (54) and / or the first contact portion (12) are tapered.

7. A switching device according to any one of the preceding claims, characterised in that The second isolation section (8) is a gas isolation section (22).

8. A switching device according to any one of the preceding claims, characterised in that The second contact portion (14) and the third contact portion (16) of the second isolating segment (8) are elastically supported in the direction of the switching axis (24).

9. A switching device according to any one of the preceding claims, characterised in that During the switching process, an intermediate state (26) exists in which the contacts of the first isolating section (6) and the second isolating section (8) are not in electrical contact.

10. A switching device according to any one of the preceding claims, characterised in that In the intermediate state (26), a switching arc (28) occurs between the contacts (32, 24) of the first isolating section (6), and a switching arc (30) occurs between the contacts (12, 14, 16) of the second isolating section (8).

11. The switch device according to claim 10, characterized in that: A switching arc (30) of the second isolating section (8) occurs between the first contact portion (12) and the second contact portion (14).

12. A switching device according to any one of the preceding claims, characterised in that The commutation current path (4) has a fuse (36) and / or a semiconductor element.

13. A switchgear according to any one of the preceding claims, characterised in that The first insulating segment (6) has a fixed contact portion (32) and a movable contact portion (34), the movable contact portion (34) being supported so as to be able to translate along a switch axis (24), and when the first insulating segment (6) is closed, a mechanical contact force (48) acts between the movable contact portion (34) and the fixed contact portion (32) in an axial direction.

14. A switching device according to any one of the preceding claims, characterised in that The first insulating section (6) is a vacuum insulating section, and is particularly designed as a vacuum switching tube (10).

15. Method for switching an electric current by means of a switching device (2) according to any one of claims 1 to 14, wherein: In the second contact position (20), a mechanical contact force (52) is generated in a radial direction between the first contact portion (12) and the third contact portion (16).

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