Device for Interrupting an Electrical Current Circuit

Abstract

The invention relates to a device for interrupting an electrical current circuit, more particularly a device of this kind that can safely perform a disconnection in a current range up to 100 kA. The device comprises a pyrotechnic switch (PTS) and a safety fuse, wherein the PTS and the safety fuse are connected in series and wherein the PTS can be actively triggered. The PTS is preferably triggered as a result of a current flowing in the current circuit only if the current measured in the current circuit has exceeded a particular value for a particular period of time (filtering time of the PTS).

Claims

1.-33. (canceled)

34. A device for interrupting an electrical circuit, comprising a pyrotechnic fuse element (PTS); and a fusible link, wherein the PTS and the fusible link are connected in series and wherein the PTS can be actively triggered.

35. The device as claimed in claim 34, wherein the PTS is triggered on account of a current flowing in the electrical circuit only if the current measured in the electrical circuit has exceeded a specific value for a specific time duration (filtering time of the PTS).

36. The device as claimed in claim 35, wherein the PTS is not triggered until a further specific time duration (delay time of the PTS) has also elapsed after the end of the filtering time.

37. The device as claimed in claim 35, wherein the filtering time of the PTS and/or the delay time of the PTS vary automatically depending on the external temperature.

38. The device as claimed in claim 35, wherein the PTS can also be triggering independently of the measured current.

39. The device as claimed in claim 35, wherein the filtering time of the PTS is at least 500 s.

40. The device as claimed in claim 35, wherein the filtering time of the PTS is in the range of between 500 s and 3 ms.

41. The device as claimed in claim 35, wherein the sum of the filtering time of the PTS and the delay time of the PTS (triggering time of the PTS) is in the range of between 0.5 ms and 30 ms.

42. The device as claimed in claim 35, wherein fusible link (23) can disconnect safely in a current range up to at least 100 kA in the temperature range of 40 C. to 125 C. within the triggering time of the PTS.

43. The device as claimed in claim 35, wherein the fusible link can disconnect safely in a current range beginning at 4 kA within the triggering time of the PTS in a temperature range of 40 C. to 125 C.

44. The device as claimed in claim 35, wherein the PTS can disconnect in a current range of from 0 to at least the minimum current of the fusible link, wherein the minimum current of the fusible link is the weakest current for which the fusible link still disconnects within the triggering time of the PTS.

45. The device as claimed in claim 34, wherein the PTS comprises an explosive charge in a body.

46. The device as claimed in claim 34, wherein the PTS is activatable by an electrical igniter.

47. The device as claimed in claim 34, wherein the PTS comprises a hollow cylinder in which a piston is situated, below which is situated a disconnecting claw, below which is situated a conductor that when severed interrupts the electrical circuit.

48. The device as claimed in claim 47, wherein the disconnecting claw is embodied in a solid fashion to withstand a plasma fire for a required time.

49. The device as claimed in claim 47, wherein a supply of an extinguishing substance is situated in a chamber outside the cylinder, which extinguishing substance can move into a disconnecting chamber after the PTS has been triggered.

50. The device as claimed in claim 49, wherein residual pressure of the explosion of the explosive charge accelerates movement of the extinguishing substance into the disconnecting chamber.

51. The device as claimed in claim 47, wherein a counterpart to the disconnecting claw is situated below the conductor, said counterpart having a shape complementary to that of the disconnecting claw.

52. The device as claimed in claim 34, wherein the PTS has a permanent magnet and a magnetic field concentrator arranged parallel to the conductor.

53. The device as claimed in claim 34, wherein two opposite side walls of the PTS are formed by iron plates.

54. The device as claimed in claim 53, wherein the iron plates are premagnetized, whereby a magnetic field from the iron plates can extinguish plasma sparks arising in the PTS after interruption of the electrical circuit.

55. The device as claimed in claim 34, wherein the PTS has a disconnecting claw configured to sever the conductor after the PTS has been triggered and which is immersed in a chamber with extinguishing substance after the disconnection.

56. The device as claimed in claim 34, wherein two side walls of the PTS are each connected to opposite ends of the conductor.

57. The device as claimed in claim 34, wherein plasma sparks that possibly arise in the fusible link after a disconnection are extinguished with the aid of an extinguishing sand contained in the fusible link.

58. The device as claimed in claim 34, wherein the fusible link comprises at least one fusible conductor.

59. The device as claimed in claim 58, wherein the fusible conductor is a metal strip comprising copper and silver.

60. The device as claimed in claim 34, wherein the fusible link comprises two substantially plate-type covers.

61. The device as claimed in claim 60, wherein at least one of the two plate-type covers comprises iron.

62. The device as claimed in claim 60, wherein one plate-type cover of the fusible link is connected to an end of a conductor that is part of the electrical circuit.

63. The device as claimed in claim 60, wherein one of the plate-type covers of the fusible link is simultaneously one of the two premagnetized plates of the PTS.

64. The device as claimed in claim 34, wherein the fusible link and the PTS are surrounded by a common insulation sheath.

65. The device as claimed in claim 34, wherein the fusible link and the PTS are integrated in one component.

66. The device as claimed in claim 65, wherein the integrated component is configured to be cooled by a cooling installation.

Description

[0034] The invention is explained in greater detail with reference to the figures. In the figures:

[0035] FIG. 1: shows an interrupting device according to the invention

[0036] FIG. 2: shows an interrupting device according to the invention

[0037] FIG. 3: shows an interrupting device according to the invention

[0038] FIG. 4: shows one preferred embodiment of a disconnecting claw

[0039] FIG. 5: shows one preferred embodiment of a disconnecting claw

[0040] FIG. 6: shows a circuit comprising an interrupting device according to the invention

[0041] FIG. 7: shows an interrupting device according to the invention after the PTS has been triggered

[0042] FIG. 1 shows an interrupting device according to the invention in a vertical cross section and in plan view before the triggering of the pyrotechnic fuse element (PTS). The interrupting device is substantially parallelepipedal. The parallelepiped has, in particular, two end faces 1, 2 and a base face 3. In the plane of the base face 3, a rectangular metal plate 4 and 5 respectively extends outward from each end face.

[0043] The interrupting device comprises a fusible link and a pyrotechnic fuse element (PTS). One end wall 2 of the interrupting device is formed by a side wall of the PTS. The other end wall 1 is formed by a side wall of the fusible link. Both end walls 1, 2 are respectively connectable to an end of a conductor, for example composed of copper, that is part of the electrical circuit. One side wall 6 of the fusible link is simultaneously a side wall of the PTS. This common side wall 6 is a plate-type cover composed of iron.

[0044] The side walls of the interrupting device which are not end walls 1, 2 comprise an insulation sheath 7 having suitable thermal properties.

[0045] A plurality of strip-shaped fusible conductors 8a, 8b, 8c are situated between the common side wall 6 of the fusible link and the PTS and the opposite side wall 1 of the fusible link. The strip-shaped fusible conductors 8a, 8b, 8c lie partly in planes that are perpendicular to one another. The fusible conductors 8a, 8b, 8c have sections composed of copper and sections composed of silver. The sections of the fusible conductors which consist of silver have holes.

[0046] The PTS comprises a body 9 with an explosive charge situated therein. The PTS is activatable by an electrical igniter the contacts 10 of which are situated at the top side of the interrupting device.

[0047] The PTS comprises a hollow cylinder 11, in which a piston 12 is situated. A disconnecting claw 13 is situated below the piston. When the explosive charge explodes, the piston 12 and thus also the disconnecting claw 13 are pressed downward.

[0048] A supply of extinguishing sand (not shown in the drawing) is situated in a chamber 14 outside the cylinder 11. As long as the PTS has not triggered, the disconnecting claw 13, with its outer surfaces, closes an opening in the extinguishing sand supply chamber 14. FIG. 7 shows the interrupting device after the triggering of the PTS. When the piston 12 and the disconnecting claw 13 are pressed downward and reach their end position after the triggering of the PTS, the extinguishing sand supply chamber 14 is opened toward the disconnecting chamber 15 as a result. The extinguishing sand then moves into the disconnecting chamber 15. As a result of the piston 12 and the disconnecting claw 13 being pressed down, holes 16 are furthermore opened, through which pressure can escape into the extinguishing sand supply chamber 14 through a pressure diverting channel 17, as a result of which the extinguishing sand, which is sealed from above, is forced from the extinguishing sand supply chamber 14 into the disconnecting chamber 15. The residual pressure of the explosion is thus used to bring about or to accelerate the movement of the extinguishing substance, which is intended to smother a plasma fire that possibly arises, into the disconnecting chamber 15.

[0049] The PTS has a permanent magnet 18 and also a magnetic field concentrator 19 composed of cold-rolled iron sheets or soft iron wires, which is arranged parallel to the conductor 20 that is intended to be severed. Plasma sparks that possibly arise in the PTS after the disconnection are thereby intended to be able to be extinguished.

[0050] The counterpart 21 to the disconnecting claw 13 is situated below the conductor 20 to be severed by the disconnecting claw 13, the shape of said counterpart being complementary to that of the disconnecting claw. The counterpart 21 is likewise composed of insulating material. The counterpart has the shape of a dome with a cylinder 22 seated on its apex, the horizontal end face of said cylinder being arranged below the conductor 20.

[0051] When the disconnecting claw 13 is pressed downward upon the triggering of the PTS, it severs the conductor 20 at two points. That piece of the conductor 20 which is cut out in this way is fixed by virtue of the fact that it is clamped in between the cylinder 22 at the apex of the counterpart and the disconnecting claw, and is deformed by the shape of the counterpart 21 and/or of the disconnecting claw 13, such that the insulation clearance becomes maximal

[0052] FIG. 2 shows the interrupting device according to the invention in accordance with FIG. 1 in a side view and horizontally cut away from above.

[0053] FIG. 3 shows an interrupting device according to the invention in a semi-transparent illustration.

[0054] FIGS. 4 and 5 show preferred embodiments of the disconnecting claw 13.

[0055] FIG. 6 shows a circuit comprising an interrupting device according to the invention. The PTS 23 and the fusible link 24 are connected in series. The PTS 23 is triggered on account of a current flowing in the electrical circuit only if the current measured in the electrical circuit has exceeded a specific value for a specific time duration (filtering time of the PTS). The triggering is not effected until additionally a specific further time duration (delay time of the PTS) has also elapsed. However, the triggering can also be initiated independently of the measured current.