EP0917721B1 - Sf6 gas-insulated switch installation for electricity distribution supply networks - Google Patents

Abstract

An SF6 gas-isolated switch installation for several switchboard sections, each with a three-pole separating switch and an earthing device. A switchboard section is equipped with a separating switch designed as a transformer switch. This can be a load-break switch, whose phases are combined with cutouts, or a load-isolating breaker. The switch installation has for the support of mobile switch contacts and the connection of cables and/or cutouts appropriate lead-throughs in the housing walls and switch shafts mounted on said walls, as well as omnibus bars for the fixed contact of phases L1, L2 and L3, and individual phase quenching devices directly connected to the omnibus bars (9). The quenching devices of the load-break switches that do not function as as transformer switches are equipped with sheet steel quenching chambers. Breaking ability must be enhanced with no extra space requirement. For this purpose blow-out coils (13, 13a) are introduced according to an arrangement which when in off position meets the requirements for a disconnected section, with a contact arrangement corresponding to the remaining load-break switches for the three phases of the switch designed as a transformer switch.

Description

The invention relates to an SF ₆ gas-insulated switchgear for distribution networks with switch disconnector cable panels and a switch disconnector-fuse combination or a circuit breaker with a isolating section (circuit breaker) for transformer protection.

Switchgear of this type is known. In network distribution stations are usually Medium voltage switchgear with three panels, two of which are used Ring cables connected and a control panel with high voltage fuses or a circuit breaker for a transformer feeder.

From DE-OS 38 20 489 an SF ₆ gas-insulated switch disconnector arrangement is known, in which the switch disconnectors are arranged in an encapsulated housing filled with sulfur hexafluoride (SF ₆ ), a fixed and movable contact piece, an earth contact, and one out of each phase Extinguishing plates have existing extinguishing device, and in which the fixed contact pieces of the same phases are attached directly to a busbar and the extinguishing devices are each arranged next to them directly on the busbar.

To keep such a switchgear smaller and easier to assemble To be able to design, are in a further development, which is the subject of the DE considered the closest prior art 40 11 397 C2 has led, essential parts of the switch disconnectors in a prefabricated Assembly has been summarized in the initially open housing inserted and connected to it. Those belonging to the earthing device Ground contacts are attached to the switch shaft in this switchgear and easy to assemble.

Arranged on the phases of the load break switch or the circuit breaker Arc extinguishing devices have the task of Quickly extinguish the arc when you turn it off by opening the Contacts and the evaporation of the last metal bridge caused by the heat of electricity, to ensure the switching ability of the switches. When AC comes it depends on the charge carriers in the short time between a zero current crossing and effectively reduce the oscillation of the recurring voltage.

In addition to the extinguishing devices consisting of fire-extinguishing sheets, there are others Extinguishing devices for electrical switching devices known, including quenching coils, in which the resulting arc is commutated and then the coil flowing current generates a magnetic field that causes the arc rotated and finally deleted. For example, EP 0 012 522 describes an electrical one Switchgear with quenching coils on the fixed contacts. EP 0 021 577, EP 0 058 007 and EP 0 313 106 B1 have electrical switching devices with quenching coils as arc extinguishing devices to the subject.

In the SF ₆ switchgear systems mentioned at the outset, the load-break switch of a switchgear panel is combined with a fuse attachment with high-voltage fuses with a striker, which may be encapsulated, the load-break switch being equipped with a storage drive with a trip memory which can be actuated by a striker of one of these fuses via a trigger linkage , With regard to the interaction of the fuses with the switch disconnector, wishes remain open. Limits are also set with regard to the breaking capacity (level of the nominal fuse current) and the associated fulfillment of the isolating path conditions with regard to the quenching plate arrangement used as the extinguishing device.

It is an object of the invention to provide an SF ₆ gas-insulated switchgear according to the preamble of claim 1 with an increased breaking capacity with a constant space requirement for the switch arrangement.

Both the switch disconnector and the circuit breaker must do so be designed so that they meet the separation conditions, so depending have a required dielectric strength from the nominal voltage. As well both switches must be designed so that they ensure their switching ability, by checking the switching arc in the shortest possible way and Clear.

This object is achieved in an SF ₆ gas-insulated switchgear according to the preamble of claim 1 by its characterizing features. The generic switchgear comprises a plurality of switchgear panels with three-pole switch disconnectors and an earthing device, of which one switchgear panel is equipped with a switch disconnector designed as a transformer switch, the phases of which are combined with fuses, or can have a circuit breaker, and in which the fixed contacts of the phases L1, L2 and L3 are firmly connected to busbars, on which quenching devices for the individual phases are arranged, the quenching devices for phases L1, L2 and L3 of the switch designed as a transformer switch having a switch contact arrangement corresponding to the other switches, quenching coils and the quenching devices for the phases of the invention other isolating switches are known extinguishing chambers with quenching plates.

The isolating path conditions are met with a circuit breaker and the means for ensuring the switching ability - for those with switches with arcing chambers given spatial conditions and a corresponding switch contact arrangement - Given when the quenching coils are arranged and designed in this way are that their coil axis with that in the off position Switching contact encloses an obtuse angle on the fixed contact side and the free one End of the switch contact in the switch-off position in the area of the coil axis is that the coil radius is at least the distance between the in the off position located switch contact and the fixed contact corresponds and that the fixed contact side coil edge area a minimum distance to the fixed contact and the free end of the switching contact moved past.

In the case of a switch disconnector, the isolating conditions are met and the means to ensure the switching ability if the quenching coils arranged in this way and are designed so that their coil axis with the in the off position switch contact located on the fixed contact side at a right or obtuse angle and the quenching coils each take over the base point of the arc Have guide element that in the immediate vicinity of the fixed contact extends and tangential to the path of movement of the free end of the switch contact is arranged. To ensure the switching capacity of the switch disconnector the guiding element plays an essential role: it transports the between the Switching knife and the contact arcing along the guide element in the sink. The arc remains very short due to the short distance, but quickly and safely reaches the inner path of the quenching coil. The guiding element has hence the task of facing an arrangement of a switch disconnector a circuit breaker with a smaller quenching coil at a distance from the busbar contact and with this arrangement, changing the arc into the To enable quenching coil.

The arrangement of quenching coils on the transformer switch leads to one increased breaking capacity of the switchgear for a given unchanged Arrangement space, with the increased requirements for switch disconnector-fuse combinations or the elimination of short-circuit currents can be worn, and thus represents a significant technical advance represents.

The quenching coil and the fixed contact for the respective phase L1, L2 and L3 can expediently be arranged on a common cross member, the is connected to the busbar for the respective phase and to which the movable switch contact is pivotally arranged such that it from the at the switch-on position given in the fixed position in a parallel to the cross member Switch-off position and can be swiveled into an earthing position is.

The quenching coils can be arranged so that their coil axis with the in the switch-off position switch contact facing the fixed contact Includes an obtuse angle, preferably 165 ° to 175 °, or is arranged perpendicular to the switch contact in the switch-off position.

In the latter quenching coil arrangement, the fixed contact is in the center of the Quenching coil, and the guide element is directed into the inside of the coil.

To avoid increased erosion on the edges of the contacts at higher ones Switch-off currents (circuit breakers) can free ends of the moving Switch contacts and the tear-off edges of the fixed contacts with caps and burn-off strips be provided, the more erosion-resistant material than the respective contact material consist.

Finally, to facilitate assembly and reduce the need for Installation of the required space in the switchgear, the quenching coils and the quenching chambers with one that can be inserted into the housing, which is initially open on the back Be connected to the assembly. This assembly can be made from the busbars, the fixed contacts attached to these with cross beams, supports for the cross beams and holding devices can be formed for arrangement on the housing. The three for Grounding contacts belonging to the grounding device are on the switch shafts attached.

Fig. 1:

eine erfindungsgemäße SF6-gasisolierte Schaltanlage in Draufsicht (Lasttrennschalter),

Fig. 2:

die Schaltanlage in Rückansicht (Leistungstrennschalter),

Fig. 3:

eine Phase des mit Sicherungen kombinierten Lasttrennschalters,

Fig. 4:

eine andere Ausführung einer Phase des mit Sicherungen kombinierten Lasttrennschalters und

Fig. 5:

eine andere Fest- und Schaltkontaktausführung bei einem Leistungstrennschalter.

The invention is explained below using exemplary embodiments. In the accompanying drawings:

Fig. 1:

an SF6 gas-insulated switchgear according to the invention in plan view (switch disconnector),

Fig. 2:

the switchgear in rear view (circuit breaker),

Fig. 3:

a phase of the switch disconnector combined with fuses,

Fig. 4:

another version of a phase of the switch disconnector combined with fuses and

Fig. 5:

another fixed and switch contact version for a circuit breaker.

1, the gas-insulated switchgear consists of a gas-tight housing 1, in the three panels I, II and III, each with a three-pole switch disconnector and a grounding device. The control panel I houses one designed as a transformer switch disconnector, whose phases L1, L2 and L3 are combined with fuses (not shown) via bushings 2.

The switch disconnectors have switch blades 3 as movable switching contacts are designed as a double knife. The switching blades 3 are at rest for phase L2 each directly on the respective bushings 2, for which phases are L1 and L3 special switch blade support used with the associated bushings 2 are connected by bearing pieces (not shown). Implementations 2 are all located on the front 4 of the housing 1. The actuation of the Switching knife 3 takes place via a switch shaft mounted on the walls of the housing 1 5, the lever 6 and a coupling rod 7 with the switching knife 3rd connected is. A ground contact 8 is connected directly to the switch shaft 5.

The switching knife 3 can take three positions. When switched on the respective switch blade 3 contacts one firmly connected to a busbar 9 Fixed contact 10. The switch-on state is shown in panel III. in the the switched-off knife 3 is brought into a position, which lies between the fixed contact 10 and the ground contact 8. This switching state is shown in panel II. The respective contacts in the grounded state Switching knife 3 the ground contact 8, shown in panel I.

In the housing 1 there are three busbars 9, on each of which the fixed contacts 10 of the respective phases L1, L2 and L3 of the switch disconnectors are arranged. Furthermore, extinguishing devices are on the busbars 9 for each phase L1, L2 and L3 arranged, of which the extinguishing devices at the phases of Fuse-free switch-disconnectors in cubicles II and III equipped with extinguishing plates Arcing chambers 12 and the extinguishing devices at the phases of the Fuses combined switch disconnector of the control panel I quenching coils 13a are. These (13a) and the fixed contacts (10) are on one with the respective busbar 9 connected cross member 14 to which the switching knife 3 in Switch-off position are aligned in parallel. The quenching coils 13a are arranged in such a way that their coil axis A with the switch contact located in the switch-off position 3 on the side facing the fixed contact 10 an obtuse angle α of about 165 ° (Fig. 2).

The quenching coils 13a and the quenching chambers 12 are connected to the busbars 9, the arranged on cross members 14 and via this with the busbars 9th firmly connected fixed contacts 10, supports 15 for the cross member 14, holding devices 16 and struts 18 for arrangement on the housing 1 to form a structural unit joined together, which can be inserted into the housing 1 via the rear side 19, before it is sealed gastight.

The quenching coils 13a each have an electrical connection to the end of the coil winding connected guide plate 17 in the immediate vicinity of the respective fixed contact 10 on, which has the width of a switching knife 3 and tangential to the trajectory the free end of the same is arranged.

Fig. 2 shows the three busbars 9 and those on busbar sections 9a arranged quenching coils 13. These are on the cross beams 14, the also carry the fixed contacts 10, firmly arranged, the cross member in turn supported on the housing via the supports 15, holding devices 16 and struts 18 are. It can be seen that the control panel I (circuit breaker) is not a larger one Arrangement space in the housing 1 as the panels II and III claimed.

In Fig. 3 the arrangement of an erase coil 13a is shown enlarged on one phase. The quenching coil 13a is held on a tab 20, both with the start of the winding the quenching coil 13a and with the cross member 14 and thus with the Busbar 9 is electrically coupled.

Fig. 4 shows an alternative quenching coil arrangement for the same switchgear, at the quenching coils 13a are arranged on a tab 21 such that the coil axis A with the switch blade 3 in the switched-off position a right one Includes angle β, the quenching coils 13a enclosing the fixed contacts 10. The quenching coils 13a in turn have an electrical connection to the end of the coil winding connected baffle 17 in the immediate vicinity of the respective fixed contact 10 on, which has the width of a switching knife 3 and tangential to the path of movement the free end of the same is arranged.

The free ends of the switching knife 3 can in the illustrated embodiments the switchgear according to the invention for higher cutoff currents to increase the erosion resistance with caps 22 and the fixed contacts 10 with erosion bars 23 be provided. The material of the caps 22 and the erosion bars 23 is more resistant to erosion as the base material of the respective contact 3 or 10 (Fig.5).

Claims (6)

1. An SF6 gas-insulated switchgear assembly for power distribution networks, comprising a gas-tight housing for several switchboard sections each having a three-pole load-break switch and an earthing device, of which one switchboard section is provided with a load-break switch designed as a transformer switch whose phases are combined with fuses, or it may have a power isolating switch, comprising feed-throughs suitable for supporting mobile switch contacts and for the connection of cables and/or fuses in the walls of the longitudinal sides of the housing, and comprising switch shafts mounted thereon and bus-bars for the fixed contacts of phases L1, L2 and L3 and quenching devices for the individual phases which are connected directly to the bus-bars, the quenching devices of the load-break switches which are not used as transformer switches being quenching chambers provided with de-ion plates, characterised in that the quenching devices for phases L1, L2 and L3 of the switch designed as a transformer switch with a switch contact arrangement corresponding to the remaining switches are quenching coils (13; 13a) in an arrangement which meets the isolating distance conditions in the open state, and have means which ensure the switching capability,
   wherein the quenching coils (13) for the power isolating switch are arranged and designed in such a way

   that their coil axis (A) encloses an obtuse angle (α) on the fixed contact side with the switch contact (3) in the open position, and the free end of the switch contact (3) lies in the region of the coil axis (A), and the coil radius corresponds at least to the distance between the switch contact (3) and the fixed contact (10)

   and the coil edge region thereof on the fixed contact side is a minimum distance away from the fixed contact (10) and the free end of the switch contact (3) movable past it,

   and wherein the quenching coils (13a) for the load-break switch are arranged and designed in such a way

   that their coil axis (A) encloses a right angle or obtuse angle (β; α) on the fixed contact side with the switch contact (3) in the open position

   and they each have a deflector (17) which assumes the base point of the arc and extends into the immediate vicinity of the fixed contact (10) and is arranged tangentially to the path of movement of the free end of the switch contact (3).
2. A switchgear assembly according to claim 1, characterised in that the quenching coils (13; 13a) and the fixed contact (10) for each phase L1, L2 and L3 are arranged on a cross arm (14) connected to each bus-bar (9), with which cross arm the mobile switch contact (3) in the open position is aligned parallel.
3. A switchgear assembly according to claim 2, characterised in that the obtuse angle (a) is 165° to 175°.
4. A switchgear assembly according to claim 2, characterised in that the quenching coils (13a) are arranged and designed in such a way that they enclose the fixed contacts (10) and the deflector (17) is directed into the interior of the coil.
5. A switchgear assembly according to claim 1, characterised in that the free ends of the mobile switch contacts (3) are provided with caps (22) and the fixed contacts (10) are provided on the contact-breaking edge with arc erosion strips (23) made of a more arc-resistant material than the respective contact materials.
6. A switchgear assembly according to claim 1, characterised in that the quenching coils (13; 13a) and the quenching chambers (12) are connected to a module insertable into the housing (1) which is initially open at the back (19), the said module being composed of the bus-bars (9), the fixed contacts (10) secured thereto by cross arms (14), insulated supports (15) for the cross arms (14) and holding devices (16) for the arrangement on the housing (1), and in that the three earth contacts (8) belonging to the earthing device are secured to the switch shafts (5).

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