EP0772215A1 - Isolating switch, in particular load break isolating switch assembly for medium voltage - Google Patents

Abstract

The disconnecting or insulating switch has support insulators (4). An insulating contact is arranged at each terminal of the insulator (4). The switch has a movable contact blade, a lag contact and a closed explosion chamber (10) with a movable switch pin. The chamber (10) is preferably filled with SF6 gas. The switch has a support insulator (4) with an integral explosion chamber (10) per terminal. The explosion chambers (10) are preferably disposed between the support insulators (3,4) of a terminal. The chamber (10) may be integrated in the support insulator at which the pivot point of the contact blade is disposed.

Description

The invention relates to a circuit breaker, in particular a medium-voltage switch disconnector with post insulators, on which there is a break contact per pole, with a movable disconnect knife, a lagging contact and with a closed arcing chamber equipped with a movable switching pin, in particular filled with SF ₆ gas.

Such a load-break switch is known from German patent specification 1 154 170, in which the quenching chamber is located in a secondary flow path, which leads only briefly immediately after opening the main contact current through the retarding contact, which remains temporarily in the switched-on position, through the quenching chamber, until through which the Moving pin of the quenching chamber separating the counter-contact, the circuit is interrupted and the resulting arc is quenched in the quenching chamber.

The advantages of arranging the quenching chamber in a secondary flow path can be seen in particular in the fact that the quenching chamber is not constantly live and can be built relatively small because of its short-term current supply, with the result of a relatively low weight, which in turn means a good switching speed due to the lightness has the consequence.

Nevertheless, the known switch disconnector has considerable disadvantages. Thus, this known quenching chamber arrangement requires a relatively large amount of space and also requires a considerable structural and thus prone to failure in order to achieve the switching sequences relating to the interruption of the main and secondary flow path.

The invention is based on the problem of simplifying the switch design, in particular reducing its space requirement and improving its switching performance, while maintaining the basic advantages of arranging an arcing chamber in the secondary flow path, of the switch specified at the outset.

This object is achieved according to the invention by a post insulator with an integrated quenching chamber per pole, the quenching chamber being located between the post insulators of one pole in a preferred embodiment. Whereas the quenching chambers used to form separate units for the relevant switches, which could often only be assembled with great effort, and the switch dimensions, due to their protruding structure, also the dimensions of the switch cell, In which they are to be installed, the invention results in an extremely compact and space-saving construction paired with a very high switching reliability and switching speed.

A particularly favorable construction not only in the sense of a small space requirement, but also in terms of optimal guidance of the auxiliary current path results when the arcing chamber is integrated in the post insulator that bears the main contact with the knife pivot point. As a result, in a manner to be explained in more detail below, the secondary flow path can be implemented in a particularly simple manner by a comparatively short cable connection between the lagging contact and the arcing chamber.

As already mentioned, the lag contact ensures that the current flows briefly and temporarily on a branch line as soon as the knife interrupts the main current path by opening the associated isolating contact until the movable contact pin in the arcing chamber is released from the fixed contact and the switch-off process is thus completed .

In order to ensure this temporary tributary flow path in a particularly simple manner and to be able to coordinate the lagging contact with the movement of the separating knife as cheaply as possible in order to achieve optimal switching sequences, it has proven useful if the separating knife carries a lagging pin which is isolated and pivotable relative to this.

The size is further reduced if the cutting knife is divided lengthways and a switching kinematics for the quenching chamber is accommodated between the two cutting knife halves, which ensures a particularly reliable and high switching speed. This switching kinematics is preferably in operative connection with the switching pin of the arcing chamber and the separating knife, i.e. Depending on the respective position of the switching knife, the switching kinematics ensure the right time at which the contact in the arcing chamber is to be interrupted and the spark is to be extinguished.

A kinematics, which consists of a lever mechanism, works particularly reliably under the conditions here, an angle lever that has been proven to be articulated, which is articulated at one end to the extinguishing chamber switching pin, while the other end is mounted at an articulation point that provides an articulated connection of the free one End of an articulated lever articulated at a fixed point with the free end of a trigger linkage actuated by the cutting knife. Such kinematics mounted between the cutting knife halves not only ensures a separation process that is precisely coordinated with respect to the individual movement sequences, but also ensures a compact, space-saving construction and, due to the low weight, leads to fast switching processes.

As already mentioned, the kinematics ensure that the movable switching pin of the arcing chamber moves away from its fixed counter contact at exactly the desired time triggers up to which, via the kinematics, the switching pin is held against the excess pressure of approx. 1/2 bar in the arcing chamber.

In order to fulfill this function, two versions of the kinematics are preferably provided, namely the kinematics can be provided on the one hand with a pawl mounted on the angle lever connected to the extinguishing chamber switching pin and cooperating with a fixed locking pin, in the pivot point of which a leg spring exerting latching forces on the pawl is mounted, a stop pin for the free pawl end being located on the separating knife, while in the second version a pressure spring supported on the separating knife is arranged on the angle lever connected to the extinguishing chamber switching pin. The mode of operation of these two versions will be explained in more detail in the following description of the preferred exemplary embodiments.

The secondary current path which briefly takes over the current supply is realized in that the lag contact is electrically connected to the fixed contact in the quenching chamber, preferably via a cable, while the movable quenching chamber contact is electrically connected to the disconnecting knife pivot point via the kinematics.

Fig. 1

einen Lasttrennschalter in Seitenansicht;

Fig. 2

den dreipoligen Lasttrennschalter gemäß Fig. 1 in Frontansicht;

Fig. 3a

eine bevorzugte Antriebskinematik mit Druckfeder im eingeschalteten Zustand;

Fig. 3b

die Antriebskinematik gemäß Fig. 3a in einer Zwischenstellung, in der das Trennmesser sich bereits vom Trennkontakt gelöst hat, während der Nacheilkontaktstift und der Löschkammerschaltstift noch in Kontakt mit dem jeweils zugehörigen Festkontakt sind, d.h. der Strom nun über eine Nebenstrombahn fließt;

Fig. 3c

die Kinematik gemäß den Fig. 3a und 3b im ausgeschalteten Zustand;

Fig. 4a

eine zweite Version der Antriebskinematik mit einer Auslöseklinke im eingeschalteten Zustand;

Fig. 4b

die Kinematik gemäß Fig. 4a in der Zwischenstellung gemäß Fig. 3b; und

Fig. 4c

die Kinematik gemäß den Fig. 4a und 4b im ausgeschalteten Zustand.

Based on the accompanying drawings, in which preferred embodiments of the invention are shown, this is explained in more detail below. Show it:

Fig. 1

a switch disconnector in side view;

Fig. 2

the three-pole switch disconnector according to Figure 1 in front view.

Fig. 3a

a preferred drive kinematics with compression spring in the switched on state;

Fig. 3b

the drive kinematics according to Figure 3a in an intermediate position in which the disconnecting knife has already detached from the disconnect contact, while the lagging contact pin and the quenching chamber switching pin are still in contact with the associated fixed contact, ie the current now flows via a secondary current path;

Fig. 3c

the kinematics according to Figures 3a and 3b in the switched-off state.

Fig. 4a

a second version of the drive kinematics with a release pawl when switched on;

Fig. 4b

the kinematics according to FIG. 4a in the intermediate position according to FIG. 3b; and

Fig. 4c

the kinematics according to FIGS. 4a and 4b in the switched-off state.

FIG. 2 shows an embodiment of a switch unit as a medium-voltage switch disconnector 1, in which the three poles A, B and C of the switch unit can be seen attached to a common base frame 2. In conjunction with Fig. 1, in which switched-off state of the switch 1 is shown in dash-dotted lines, it is clear that each pole is attached to the base frame 2 with two insulators 3 and 4, in the illustrated embodiment, the upper support insulator 3 is the isolating contact support, while it is in the lower support insulator 4 is the fulcrum contact support. Accordingly, the upper support insulator 3 carries the connection or disconnect contact 5, while the contact piece carried by the lower support insulator 4 is designated 6 and has the fulcrum contact 7.

The connection between the contact pieces 5 and 6 is achieved by a separating knife 8 which can be pivoted about the fulcrum contact 7 and which, as can be seen in FIG. 2, is divided in the longitudinal direction. On the outside, one of the two cutting knife halves carries a lag contact in the form of a lag switching pin 9, which is insulated from the cutting knife 8 and is pivotably mounted on the latter. The function of this pen will be described in more detail below.

In order to quickly extinguish the spark which arises when the circuit is finally interrupted and without affecting the surroundings, each pole A, B and C is provided with an arcing chamber 10 which is integrated in the pivot contact insulator 4 in such a way that it is on the side of the pivot contact insulator 4 facing the isolating contact insulator 3, as a result of which a particularly compact and space-saving arrangement is achieved, as can also be seen in FIG. 2, since each arcing chamber lies within the surface of the base frame 2 essentially defined by the spacing of the support insulators.

The movable switching pin 11 protrudes from the arcing chamber 10 on the side facing the separating knife 8 and interacts with a fixed contact 11a in the arcing chamber 10 in a manner still to be explained in connection with the explanation of the auxiliary current path 12. The interior of the extinguishing chamber 10, which is under an overpressure of about 1/2 bar in the specific example, is sealed off from the outside atmosphere by a membrane 11b, which is only shown in FIG Blowing the spark gap when separating the contacts 11, 11a serving bore plate 11c follows.

Via a so-called actuation insulator 13, each separating knife 8 or the two knife halves belonging to a knife are, as can be seen in FIG. 1, connected in terms of drive to a drive shaft 14 common to the three poles A, B and C. As can further be seen from FIG. 2, the actuation insulators are in alignment between the cutting knife halves 8.

The desired movement coordination between separating knife 8, lag pin 9 and movable extinguishing chamber switching pin 11 is achieved by a switching kinematics 15, which is explained with reference to FIGS. 3a to c and 4a to c.

3a to c show a first variant of a kinematics version, the parts of the disconnector 1 which are not absolutely necessary for explanation being omitted or shown in simplified form for reasons of clarity. This kinematics 15 consists essentially of an angle lever 16 as a transmission lever, which is articulated with its one end 16a on the quenching chamber switching pin 11. Its other end is mounted on an articulation point 16b, which forms an articulated connection between the free end of a trigger linkage 17 actuated by the cutting knife 8 and the free end of an articulated lever 18 articulated at a fixed point 18a.

At the connection point between the kinematics 15 and the separating knife 8, the actuating sequence, i.e. the freewheel controlling the various movement sequences is provided, which in a preferred embodiment consists of an elongated hole 19 through which a stop pin 20 attached to the separating knife 8 projects. In order to keep the movable switching pin of the extinguishing chamber 10 in the switched-on position against the excess pressure in the extinguishing chamber until a point to be defined in more detail below, the angle lever 16 carries a compression spring 21 which is supported on the one hand on the angle lever and on the other hand on the separating knife 8. The effect of this kinematics 15 previously explained in its structure is as follows:

3a shows the kinematics 15 in the normal, switched-on state. If there is a switch-off process, the separating knife 8 is turned by turning the Drive shaft 14 is initially pivoted counterclockwise via the actuating insulator 13 into the intermediate position shown in FIG. 3b, in which, as can be seen from FIG. 3b, the lag pin 9 and the kinematics 15 remain in the position shown in FIG. 3a. Thus, the main current path is interrupted by the pulling of the knife 8 by the isolating contact 5, while the current now flows via the secondary current path 12, ie from the upper connection contact 5 via the trailing pin 9 further via a cable 9a and an electrical connection between this and the fixed contact of the arcing chamber 11a, via the movable quenching chamber switching pin 11 and the kinematics 15 electrically connected to the separating knife 8 to the pivot point contact 7 of the lower contact piece 6.

At this time, the compression spring 21 has already relaxed somewhat, but still acts so strongly on the movable switching pin 11 that it does not detach from the fixed contact 11a in the arcing chamber 10. Now the stop pin 20 in the slot 19 has reached the left boundary edge of the slot and acts in the sense of pivoting the kinematics 15 also counterclockwise on the release linkage 17, which also pivots the angle lever 16 counterclockwise. Only with this further movement of the separating knife 8 and now also the kinematics 15 counterclockwise, the compression spring 21 relaxes to such an extent that it can no longer withstand the excess pressure prevailing in the arcing chamber 10 and therefore the movable switching pin 11 is released from the stationary counter contact 11a , and shortly before the trailing pin 9 is separated from the isolating contact 5.

Due to the contact interruption movement of the movable switching pin 11, the piston plate 11c connected to it is moved to the left, as a result of which the pressure in the left part of the interior of the arcing chamber 10 is increased, which, due to the bores in the piston plate 11c, leads to an extinguishing gas flow in the direction of the arises when the contacts 11 and 11a are separated and thus the current flow is interrupted.

Shortly after the separation of the contacts 11 and 11a, the now de-energized lag pin 9 is released from the connection contact 5 and brought into the parallel position shown in FIG. 3c to the disconnecting knife 8. 3c also shows the relative position of the linkage parts 16, 17 and 18 of the kinematics 15 in the switched-off state.

FIGS. 4a to c show a preferred variant for the design of the kinematics 15, which differs from the kinematics explained above in connection with FIGS. 3a to c only in terms of the design which brings about the counterforce to the internal pressure of the arcing chamber 10. So this kinematics 15 has a pawl 22, which is preferably pivotally mounted in the knee of the angle lever 16 and is held in a latching position by a leg spring 23, which is supported on the one hand on the angle lever 16 and on the other hand on the pawl 22, in which it with a hook-shaped end engages behind a fixed point (pin) 24 and thereby indirectly, namely via the angle lever 16, compensates for the excess pressure of the arcing chamber as a counter-pressure component. The separating knife 8 carries a release stop 25 acting on the free end of the pawl 22 in the desired angular position of the separating knife 8.

The sequence of movements of the relevant individual parts and the switching or separation sequence of the conductive parts essentially corresponds to that previously explained in connection with FIGS. 3a to 3c, so that only the differences resulting from the "jack version" during the switch-off process are explained below .

FIG. 4a again shows the switch-on position of the kinematics 15, while FIG. 4b shows the separating knife 8 already pulled by the contact 5 in the position pivoted counterclockwise, at which time the explained action of the stop pin 20 on the kinematics takes place. At this moment, the trailing pin 9 is in turn still in electrical connection with the contact 5, so that the current now flows along the bypass path explained above, until further pivoting of the separating knife 8 in the counterclockwise direction by contacting the stop pin 20 on the left edge of the elongated hole 19 a again counterclockwise movement of the kinematics 15 is initiated, at which time finally a relative pivoting of the pawl 22 - counterclockwise - takes place via the release stop 25, which thereby releases from the locking point 24 and thus the Counteracting internal pressure of the quenching chamber 10 cancels force, so that its switching pin 11 can come loose from the mating contact 11a, as a result of which the current flow is interrupted. Shortly thereafter, the trailing pin 9 then arrives in the parallel position with the cutting knife 8, as shown in FIG. 4c.

It applies to both variants that the switch-on process can be carried out in a simple manner by pivoting the disconnecting knife 8 clockwise up to its switch-on position on the disconnect contact 5. During this pivoting movement, the separating knife 8 also brings about the return of the remaining switch parts to the starting position (switched-on state) according to FIGS. 1, 3a and 4a through the mechanical connections explained in detail above.

Claims (17)

Disconnectors, in particular medium-voltage switch-disconnectors with post insulators, on which there is one isolating contact for each pole, with a movable isolating knife, a lag contact and with a closed quenching chamber equipped with a movable switching pin, especially filled with SF ₆ gas, characterized by a post insulator ( 4) with integrated quenching chamber (10) per pole. Switch according to claim 1, characterized in that the arcing chamber (10) is located between the post insulators (3, 4) of one pole. Switch according to claim 1 or 2, characterized in that the quenching chamber (10) is integrated in the post insulator (4) at which the separating knife pivot point (7) is located. Switch according to one or more of Claims 1 to 3, characterized by a lag switching pin (9) carried by the disconnecting knife (8) and insulated and pivotable relative to it. Switch according to one or more of claims 1 to 4, characterized by a longitudinally divided separating knife (8) and a switching kinematics (15) for the arcing chamber (10) arranged between the two separating knife halves. Switch according to one or more of claims 1 to 5, characterized in that the switching kinematics (15) is in operative connection with the switching pin (11) of the arcing chamber (10) and the separating knife (8). Switch according to claim 6, characterized in that the switching kinematics (15) consists of a lever mechanism. Switch according to claim 7, characterized by an angle lever (16) which is articulated at one end (16a) to the arcing chamber switching pin (11), while its other end is mounted at an articulation point (16b) which provides an articulated connection of the forms the free end of an articulated lever (18) articulated at a fixed point (18a) with the free end of a release linkage (17) actuated by the separating knife (8). Switch according to one or more of claims 6 to 8, characterized by a freewheel at the connection point between the kinematics (15) and the separating knife (8). Switch according to claim 9, characterized in that the freewheel consists of an elongated hole (19) at the free end of the release linkage (17) through which a pin (20) attached to the separating knife (8) protrudes. Switch according to one or more of claims 1 to 10, characterized by an actuating force which counteracts the excess pressure in the arcing chamber. Switch according to Claim 11, characterized by a spring (21; 23) acting on the angle lever (16) connected to the arcing chamber switching pin (11). Switch according to Claim 11 or 12, characterized by a pawl (22) mounted on the angle lever (16) and interacting with a fixed latching pin (24), in the pivot point of which a leg spring (23) exerting latching forces on the latch (22) is mounted. Switch according to claim 13, characterized by a stop pin (25) for the free pawl end on the cutting knife (8). Switch according to claim 11 or 12, characterized by a compression spring (21) supported on the separating knife (8) on the angle lever (16) connected to the arcing chamber switching pin. Switch according to one or more of claims 1 to 15, characterized in that the lagging contact (9) is electrically connected to the fixed contact (11a) in the arcing chamber (10). Switch according to one or more of claims 1 to 16, characterized in that the movable quenching chamber switching pin (11) is electrically connected to the disconnecting knife pivot point contact (7) via the kinematics (15).

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