EP0214082B1 - On-load isolating switch of a high-tension switching unit (three-phase current switch) - Google Patents

Abstract

The invention relates to an on-load isolating switch of a high-tension switching unit (three-phase current switch) consisting of three switching elements (11, 12, 13) which in each case connect two electrical contacts and are provided with a latching device, which switching elements can be moved from the switched-on position into the switched-off position and vice versa by means of an insertion and extraction tool (manual snap-action mechanism). In order to be able to switch off or on all three switching elements (11, 12, 13) and thus all three phases (RYB) of the supply network simultaneously, the three switching elements (11, 12, 13) are connected to one another by means of a dielectric bridge (10), such that, on operation of one of the switching elements (11 to 15), all three switching elements (11 to 13) can be switched in unison. In a preferred method, only the centre switching element (12) is provided with a latching device (24) and can be operated by means of the tool (50). <IMAGE>

Description

The invention relates to a switch disconnector of a high-voltage switching unit (three-phase switch) according to the preamble of claim 1.

A switch disconnector of the generic type is previously known from DE-PS 22 40 492. The special design of the individual switching elements of this switch disconnector is described in more detail in DE-PS 22 29 865. The individual switch elements of the switch-disconnector are switched on and off one after the other using the insertion and removal tool (manual override drive). The disadvantage of this single-pole switching is that under certain circumstances of a supply network, single-pole switching leads to relatively high overvoltages as a result of the switching process. Particularly in supply networks, whose star point is grounded via earth fault quenching coils, this overvoltages can occur when large portions of the supply network are switched off, for example if only 80 or 90% of the supply power of the supply network is switched off during a switching operation. Another disadvantage of single-pole switching is that, for example, the Electric motors connected to the supply network that are not adequately protected by motor protection switches after a phase has been switched off, during which operation in the meantime can be damaged by only two phases.

Although e.g. Known from DE-PS 29 07 559 three-pole switch disconnectors for high-voltage switches. However, these are of a non-generic type.

The invention has for its object to develop a switch disconnector of a high-voltage switching unit (three-phase switch) of the generic type in such a way that all three switching elements and thus all three phases of the supply network can be switched on and off simultaneously.

The solution to this problem results from the characterizing features of claim 1. By connecting all three switching elements to one another via the insulating bridge, the invention achieves that when actuating only the middle switching element, all three switching elements can be switched together. The generic type of switch disconnector of a high-voltage switch unit is retained. The existing switching elements are changed only slightly, so that from the single-pole switch disconnector, in which all three phases have to be switched in sequence, a three-pole switch disconnector is produced, in which all three phases are switched simultaneously. Here the advantages of the three-pole switching known per se are combined with the known and proven design of a single-pole switch disconnector to be switched. It is particularly advantageous that it is very easy to retrofit existing switch disconnectors. It is only necessary to replace the switching elements. No changes are required on the stationary parts of the high-voltage switching unit.

Thus, it is provided to install the latching device for the switching elements only in the middle of the three switching elements, whereas the two outer switching elements, in contrast to the prior art according to DE-PS 22 40 492, have no latching device. The latching force to be overcome when switching on or off using the insertion and removal tool (manual spring drive) is therefore not greater than with single-pole switching.

From DE-A-2.434.438 a switch disconnector of a non-generic type is previously known, in which three tabs, each connecting two electrical contacts, are arranged lying in the housing of the switching unit. A bridge-type switching device, which grips a tab with a gripping support and is additionally provided with fixed and movable contacts, enables the three tabs to be switched on or off together, but in a completely non-generic design. Advantageous embodiments of the invention result from the subclaims.

Fig. 1

die Hochspannungsschalteinheit (Drehstromschalter) mit eingesetztem Lasttrennschalter in der Einschaltstellung,

Fig. 2

eine Draufsicht auf den Lasttrennschalter,

Fig. 3

den in die Hochspannungsschalteinheit eingeführten, noch nicht eingeschalteten Lasttrennschalter,

Fig. 4

eine Seitenansicht des Lasttrennschalters,

Fig. 5

die Vergrößerung des Details A aus Fig. 1 mit der Rasteinrichtung im mittleren Schaltelement,

Fig. 6

die Hochspannungsschalteinheit mit einer Prinzipdarstellung des mit der Rasteinrichtung versehenen mittleren rohrförmigen Schaltelements,

Fig. 7

eine prinzipielle Stirnansicht gemäß Pfeil Z in Fig. 6,

Fig. 8

eine teilweise geschnittene Seitenansicht des Einsetz- und Abziehwerkzeuges (Handsprungantrieb) und

Fig. 9

einen Schnitt gemäß der Linie B-B in Fig. 8.

The invention is explained below with reference to an embodiment of a load break switch of a high-voltage switching unit (three-phase switch) shown in more detail in the drawings. Show it:

Fig. 1

the high-voltage switch unit (three-phase switch) with the load-break switch inserted in the switch-on position,

Fig. 2

a plan view of the switch disconnector,

Fig. 3

the load-break switch inserted into the high-voltage switching unit and not yet switched on,

Fig. 4

a side view of the switch disconnector,

Fig. 5

the enlargement of detail A from FIG. 1 with the latching device in the middle switching element,

Fig. 6

the high-voltage switching unit with a schematic diagram of the central tubular switching element provided with the latching device,

Fig. 7

2 shows a principal end view according to arrow Z in FIG. 6,

Fig. 8

a partially sectioned side view of the insertion and removal tool (manual spring drive) and

Fig. 9

8 shows a section along line BB in FIG. 8.

The high-voltage switching unit 63 shown in FIG. 1 corresponds in its basic structure to the high-voltage switching unit according to DE-PS 22 40 492. The two-part plastic housing of the high-voltage switching unit 63 has on its underside three connecting terminals 64, 65, 66 for the three phases R, S, T of a high voltage - three-phase network. These are connected in the interior of the housing via busbars 42, each with a main contact piece 33, as shown in FIG. 3. Furthermore, there are three taps in the housing of the high-voltage switching unit 63 at a distance from the main contact pieces 33 provided counter contacts 43 arranged. These can be connected to the main contact pieces 33 via tubular switching elements 11, 12, 13, as described in more detail in DE-PS 22 40 492. The special design of the individual tubular switching elements 11, 12, 13 is described in more detail in DE-PS 22 29 865.

Each tubular switching element 11, 12, 13 essentially consists of a tubular main current path 14, which is used for the electrical connection of a main contact piece 33 to a mating contact 43, and a coupling connection 24, 35 (not described in more detail here) for the switch-on position. An insulating sleeve 30 is attached to the outer end of each tubular main current path 14. At the free end of this insulating sleeve 30, a cup-shaped insulating hood 31 is attached, which encloses the insulating sleeve 30 and part of the tubular main current path 14 at a distance, as is shown in particular in FIG. 3. In the switched-on position according to FIG. 1, the insulating material covers 31 surround sleeve-shaped insulating parts 78, which are attached to the housing of the high-voltage switching unit 63, as shown in FIG. 6.

The insulating material hoods 31 of the three switching elements 11, 12, 13 are provided on the outside with ribs 85 on the end directed towards the main current path 14, to which a cylindrical part 86 adjoins the other end. The cylindrical parts 86 of the insulating material hoods 31 are received in an insulating material bridge 10, as is shown in particular in FIGS. 3, 4 and 5.

The insulating material bridge 10 is U-shaped in cross section (FIG. 4), the side webs 87 being chamfered from the center outwards, as shown in FIG. 3. The base 88 of the U-shaped insulating material bridge 10 is provided with three bores 77, to the central bore 77 of which a pipe section 76 is connected, which is firmly connected to the base 88. The two outer bores 77 are provided with pipe pieces 76 which are only attached. The three switching elements 11, 12, 13 with the cylindrical parts 86 of their insulating material hoods 31 are inserted into the tube pieces 76 from the base 88, the ribs 85 coming into contact with the base 88 of the insulating material bridge. The pipe pieces 76 thus plugged in are secured by wedges 18 on the cylindrical part 86 of the insulating material hoods 31. The wedges 18 are secured to all three switching elements 11 to 13 by fastening screws 71, the projecting screw heads of which prevent the insertion of a manual spring drive for single-pole switching.

Thus, the three switching elements 11, 12, 13 are rotatably mounted in the insulating material bridge 10, but are axially positively fixed between the ribs 85 and the wedges 18. The switching elements 11, 12, 13 and the insulating material bridge 10 thus form a structural unit. In the base 88 of the insulating material bridge 10, three openings 73 for performing voltage testers for each switching element 11 to 13 are formed.

A latching device 44 is arranged in the middle switching element 12, which is shown in more detail in FIG. 5. This consists of two in the Insulating sleeve 30 of the main current path 14 inserted locking pins 45, which are directed radially outwards under the action of an inner compression spring 46. In an insulating sleeve 74 of the sleeve-shaped insulating part 78 of the fixed high-voltage switching unit 63, two latching recesses 47, 48 are formed at an axial distance from one another, with which the latching pins 45 of the latching device 44 cooperate, as is shown in FIGS. 5 to 7. In the switch-off position (position a), the locking pins 45 are located in the outer recess 48 of the insulating material bushing 74 of the insulating part 78. After a rotation through 90 ° in the clockwise direction (FIG. 7), the locking pins 45 come into the ready position for switching on (position b) , in which the locking pins 45 start against stops in the insulating sleeve 74. In this rotational position of the switching element 12, it can be pressed into the high-voltage switching unit 63 in the direction of arrow Z by means of the insert and removal tool (manual spring drive) 50 shown in FIG. 8, in order to electrically connect the three main contact pieces 33 with the mating contact pieces 43 via the main current paths 14 connect with each other. When the connection is reached, the locking pins 45 engage in the axially inward recess 47 (position c).

Since the outer switching elements 11, 13 are also carried along when the middle switching element 12 is pressed in via the insulating bridge 10, a three-pole switching of all three phases of the high-voltage switching unit 63 is carried out by means of a single switching-on operation. It will again pointed out that the outer switching elements 11, 13 have no locking devices.

To switch off the high-voltage switching unit 63, the switching elements 11, 12, 13 must be pulled out by means of the tool 50, the latching force of the latching spring 46 of the latching pins 45 of the latching device 44 of the middle switching element 12 engaging in the latching recesses 47 having to be overcome. A tension spring 75 is used to automatically reset the middle switching element 12 when switching off from position b to position a. The insertion and removal tool (manual jump drive) 50 is shown in FIG. 8. This consists of a handle 58, a connecting head 81 for engaging in the socket 82 of the middle switching element 12 and two parallel connected spring devices 51 connecting the handle 58 and the connecting head 81. Each spring device 51 consists of a telescopic housing 80, of two interlocking ones and sleeves 52, 62 which can slide into one another. The sleeve 62 is firmly connected to an end plate 60 fixedly attached to the handle 58. The sleeve 52 is slidable in the sleeve 62 and is pressed out of the sleeve 62 up to the stop 41 under the action of a compression spring 54 supported on the bottom of the sleeve 52. The compression spring 54 is supported on the bottom of the sleeve 62 via a plate 89. The free end of the sleeve 52 is slidably received on a tube piece 90 which is fixedly connected for connecting the two telescopic housings 80 to an end plate 59 which in turn carries the connecting head 81. In the pipe section 90, the head 91 of a push rod 92 is slidably guided, which is firmly screwed at its other end to the plate 89 of the compression spring 54.

The connecting head 81 is connected to the end plate 59 via a tubular extension 93, 93 'of a disk-shaped coupling part 55. On the tubular extension 93, 93 ', a union sleeve 56 is axially displaceably mounted against the action of a compression spring 69, the end positions of which are delimited on the one hand by the end face of the end plate 59 and on the other hand by a pin 94. The tubular extension 93, 93 'of the coupling part 55 is formed as a coupling by a parting plane 93' 'which is V-shaped in side view and which is held together by means of a compression spring 68 acting on an inner sleeve 55' '. The compression spring 68 pulls the sleeve 55 '' attached to the tubular extension 93 'coupling part 55 against the tubular connection 93 fixedly connected to the end plate 59 via the V-coupling, so that the coupling part 55 is carried when the middle switching element 12 from Position a is rotated into position b. (Fig. 7). If over an angle of more than 90 °, i.e. Should be rotated via the position b, the coupling part 55 of the connecting head 81 disengages via the V-coupling 93 ″ and the spring 68. This ensures that due to excessive forces acting on the switching element 12 from the tool 50, no defects can occur on the locking device 44, the locking positions of which are arranged at an angle of 180 ° to one another.

The disc-shaped coupling part 55 is inside an end cylindrical recess of the sleeve 56 is arranged. The coupling part 55 is provided on one side with a slot 55 ′ and has a guide pin 72 on the side radially opposite this. A guide pin 57 loaded by a compression spring 67 is slidably arranged in the head 83 of the coupling part 55. The head 83 shown in cross section in FIG. 9 has a recess 84 so that the head 83 is oval in cross section behind a disk-shaped head part. Rubber plates 95 are pushed onto the two spring devices 51 to secure the operator.

The socket 82 formed on the end face of the switching element 12 is part of the end face of the insulating material cover 31. The socket 82 comprises a keyhole-shaped opening 32 with a slot 34 extending therefrom. A fastening screw 71 is screwed axially into the insulating material cover 31 and at the same time supports the wedge 18 Securing the insulating material bridge 10. To switch the switching elements 11, 12, 13 on and off, the connection head 81 of the tool 50 is inserted into the socket 82 of the middle switching element 12, the head 83 in the opening 32 and the fastening screw 71 in the radial slot 55 'of the coupling part 55 engage. The pin 72 of the coupling part 55 engages in the slot 34 of the opening 32. The union sleeve 56 encloses the cylindrical part 86 of the insulating material cover 31, a slot 56 ′ engaging in the front circumference of the sleeve 56 over the wedge 18. In this way, the switch-disconnector can be switched on and off by means of the tool 50, as will be described below.

To switch on, the three switching elements 11, 12, 13 are located in the high-voltage switching unit 63 such that the latching device 44 is in the position a (pre-locking), in which the latching pins 45 meet a stop 79 which ensures the position a. The position a also ensures that the detent cannot be run over when the switching element 12 is inserted. The speed is decisive for the electrical switch-on capacity. A constant speed can only be achieved from the rest position of the switching element. After the middle switching element 12 has been rotated into position b by means of the handle 58, the two compression springs 54 of the two parallel spring devices 51 are pressed together by means of the handle 58 until they are fully tensioned. The locking device 44 built into the switching element 12 blocks the switching element 12 for as long. The three switching elements 11, 12, 13 are then switched on abruptly after the locking device 44 has been overcome. The locking pins 45 then snap into the locking recess 47 (position c in FIG. 6).

Switching off takes place in the opposite way. Here again, the tool 50 is snapped into the socket 82 of the middle switching element 12 with its connecting head 81 in the manner described above. By pulling the handle 58, the two compression springs 54 of the two spring devices 51 are tensioned, the Sleeve 52 slides on the tube piece 90 and a parting line 96 opens between the front ends of the sleeve 52 and the end plate 59. Only after complete tensioning of both compression springs 54 can the latching device 44 be overcome suddenly, the latching pins 45 disengaging from the latching recess 47 and the assembly made of insulating bridge 10 and the three switching elements 11, 12, 13 being pulled out of the switching unit 63, the latching recess 48 is run over when switching off. Under the action of the tension spring 75, the middle switching element 12 is then turned back into the starting position (position a).

Claims (8)

1. An on-load isolating switch of a high-tension switching unit, comprising three switching elements (11 to 13) provided with a latching device (44), and the principal current paths (14) of which connect each two electrical contacts (33, 34) with each other, at the free ends of which hoods (31) of insulating material are mounted, and which can, by means of a mounting or dismounting tool (50), be brought from the switch-on position into the switch-off position and vice versa,
      characterized by that the hoods (31) of insulating material of the three switching elements (11 to 13) are connected with each other by means of a bridge (10) of insulating material,
      that the hoods (31) of insulating material are connected, in the axial direction of the three switching elements (11 to 13), by positive mechanical linkage with the bridge (10) of insulating material and are rotatably supported therein, and
      that only the central switching element (12) is provided with the latching device (44) and can be operated with the tool (50), whereby, upon operation of the central switching element (12), all three switching elements (11 to 13) can commonly be operated.
2. An on-load isolating switch according to claim 1,
      characterized by that the central switching element (12) is provided with a return spring (75) acting on the bridge (10) of insulating material.
3. An on-load isolating switch according to claims 1 or 2,
      characterized by that the bridge (10) of insulating material has a U-shaped cross section, and that the base portion (88) of the bridge (10) of insulating material is provided with three boreholes (77), at the central borehole (77) a pipe section (76) rigidly connected with the base portion (88) being attached, and the outer boreholes (77) being provided with mounted pipe sections (76).
4. An on-load isolating switch according to claim 3,
      characterized by that the side portions (87) of the U-shaped bridge (10) of insulating material are sloped downwardly, viewed from the centre.
5. An on-load isolating switch according to one of claims 1 to 4, being operated with a tool (50) composed of a handle (58), a telescopic housing (60) with two sleeves (52, 62) engaging into each other, a compression spring (54) disposed therein, and a connecting head (81) for engaging into the holder (82) of the central switching element (12),
      characterized by that for increasing the spring energy of the tool (50) during the switch-on and the switch-off procedure, two telescopic housings (80) with mounted compression springs (54) are provided parallely to each other between handle (58) and connecting head (81) of the tool (50).
6. An on-load isolating switch according to claim 5,
      characterized by that the three holders (82) of the switching elements (11 to 13) are provided with fixing screws (71) for wedges (18), the heads of which will prevent the setting-in of the tool for one-pole switching.
7. An on-load isolating switch according to claims 5 or 6,
      characterized by that the connecting head (81) of the tool (50) is provided with a coaxial pin (72) preventing the hanging-up of the connecting head (81) at a switching element (11, 13) for one-pole switching.
8. An on-load isolating switch according to one of claims 1 to 4,
      characterized by that in the base portion (88) of the bridge (10) of insulating material, openings (73) for passing voltage testers to each of the three switching elements (11 to 13) are provided.

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