WO1998006120A1

WO1998006120A1 - Sf6 gas-insulated switch installation for electricity distribution supply networks

Info

Publication number: WO1998006120A1
Application number: PCT/EP1997/004241
Authority: WO
Inventors: Rolf Dirks; Michael Kurrat; Bruno Schemmann
Original assignee: Felten & Guilleaume Energietechnik Aktiengesellschaft
Priority date: 1996-08-07
Filing date: 1997-08-04
Publication date: 1998-02-12
Also published as: CN1227663A; NO990532D0; DE19631817C1; ES2174281T3; EP0917721A1; NO317118B1; PL187349B1; KR20000029814A; BR9710807A; PL331466A1; EP0917721B1; CZ296238B6; NO990532L; CZ37999A3; CN1205633C; KR100297622B1; ATE216126T1

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

SF6 gas-insulated switchgear for distribution networks

The invention relates to an SFβ 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. Medium-voltage switchgear with three switch panels is generally used in power distribution stations, two of which are connected with ring cables and one switch panel is equipped with high-voltage fuses or a circuit breaker for a transformer feeder.

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

In order to keep such a switchgear smaller and more technically friendly in terms of assembly technology, in a further development which has led to the subject of DE 40 11 397 C2, essential parts of the switch disconnectors have been combined in a prefabricated assembly which is inserted into the initially open housing and with this is connected. The earthing contacts belonging to the earthing device are fastened to the switch shaft in this switchgear and can be assembled in a simple manner.

The arc extinguishing devices arranged on the phases of the load-break switch or the circuit-breaker have the task of quickly extinguishing the arc which occurs on them and which, when switched off by opening the contacts and the evaporation of the last metal bridge by the heat of current. stands to ensure the switching ability of the switches. With alternating current, it is important to effectively reduce the charge carriers in the short time between a current zero crossing and the oscillation of the recurring voltage.

In addition to the extinguishing devices consisting of quenching plates, further quenching devices for electrical switching devices are known, including quenching coils into which the resulting arc is commutated and, as a result of the current then flowing through the coil, generates a magnetic field which causes the arc to rotate and finally be extinguished. For example, EP 0 012 522 describes an electrical switching device with quenching coils on the fixed contacts. EP 0 021 577, EP 0 058 007 and EP 0 313 106 B1 also deal with electrical switching devices with quenching coils as arc quenching devices.

In the SFδ switchgears 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 memory 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 extinguishing plate arrangement used as the extinguishing device.

It is an object of the invention to provide an SF6 gas-insulated switchgear assembly with an increased breaking capacity with a constant space requirement for the switch arrangement.

Both the switch disconnector and the circuit breaker must be designed in such a way that they meet the isolating section conditions, that is, they have a required dielectric strength depending on the nominal voltage. Likewise, both switches must be designed so that they ensure their switching ability len by checking and extinguishing the switching arc in the shortest possible way.

This object is achieved in an SFδ gas-insulated switchgear according to the preamble of claim 1 by the characterizing features. The generic switchgear comprises several switch panels with three-pole switch disconnectors and an earthing device, of which one switch 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 are arranged for the individual phases, 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 and 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 securing the switching capability - given the space available for the switches with arcing chambers and a switching contact arrangement corresponding to these - are provided if the arcing coils are arranged and designed such that their coil axis coincides with that in the switch-off position Switch contact on the fixed contact side forms an obtuse angle and the free end of the switch contact in the switch-off position lies in the area of the coil axis, that the coil radius corresponds at least to the distance between the switch contact in the switch-off position and the fixed contact and that the coil contact area on the fixed contact side has a minimum distance to the fixed contact and the free one End of the switching contact moved past.

In the case of a switch disconnector, the isolating path conditions are met and the means for ensuring the switching capability are provided if the quenching coils are arranged and designed such that their coil axis has a right or obtuse angle on the fixed contact side with the switching contact in the switch-off position includes and the quenching coils each have a guide element which takes over the base point of the arc and extends into the immediate vicinity of the fixed contact and is arranged tangentially to the path of movement of the free end of the switching contact. The guiding element plays an important role in ensuring the switching capacity of the switch disconnector. It transports the arc that arises between the switch blade and the contact along the guide element into the coil. 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 therefore has the task of arranging the quenching coil, which is smaller in the case of a load break switch than in the case of a circuit breaker, at a distance from the busbar contact, and in this arrangement making it possible to change the arc into the quenching coil.

The arrangement of quenching coils on the transformer switch leads to an increased switch-off capacity of the switchgear for a given unchanged arrangement space, whereby the increased requirements for switch-disconnector-fuse combinations or also the switching off of short-circuit currents can be taken into account, and thus represents a significant technical advance.

The quenching coil and the fixed contact for the respective phase L1, L2 and L3 can expediently be arranged on a common cross member, which is connected to the busbar for the respective phase and to which the movable switching contact is pivotally arranged, such that it is out of the at the switch-on position given in the fixed position into a switch-off position parallel to the crossmember and beyond this into a grounding position.

The quenching coils can be arranged so that their coil axis forms an obtuse angle, preferably 165 ° to 175 °, on the side facing the fixed contact with the switch contact in the switch-off position. 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 at the edges of the contacts in the event of higher breaking currents (circuit breakers), the free ends of the movable switch contacts and the tear-off edges of the fixed contacts can be provided with caps and erosion strips, which are made of more erosion-resistant material than the respective contact material.

Finally, to facilitate assembly and to reduce the space required for assembly in the switchgear, the quenching coils and the quenching chambers can be connected to an assembly that can be inserted into the housing, which is initially open on the rear. This assembly can be formed from the busbars, the fixed contacts fastened to them with cross members, supports for the cross members and holding devices for arrangement on the housing. The three earthing contacts belonging to the earthing device are attached to the switch shafts.

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 combination with fuses

Switch-disconnector and Fig. 5: a different fixed and switching contact version at one

Circuit breaker.

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

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

The switching knife 3 can take three positions. In the switched-on state, the respective switch blade 3 contacts a fixed contact 10 which is fixedly connected to a busbar 9. The switched-on state is shown in switch panel III. In the switched-off state, the respective switching 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. In the earthed state, the respective switch blade 3 contacts the earth contact 8, shown in the control 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, quenching devices are arranged on the busbars 9 for each phase L1, L2 and L3, of which the quenching devices on the phases of the fuse-free switch disconnectors of switch panels II and III are equipped with quenching chambers 12 and the quenching devices on the phases of the switch disconnector combined with the fuses of the control panel I are quenching coils 13a. These (13a) and the fixed contacts (10) are arranged on a cross member 14 connected to the respective busbar 9, to which the switching blades 3 are aligned in parallel in the switch-off position. The quenching coils 13a are arranged such that their coil axis A with the switching Contact 3 on the side facing the fixed contact 10 includes an obtuse angle α of approximately 165 ° (FIG. 2).

The quenching coils 13a and the quenching chambers 12 are together with the busbars 9, the fixed contacts 10 arranged on cross members 14 and, via these, firmly connected to the busbars 9, supports 15 for the cross members 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 the same is closed in a gas-tight manner.

The quenching coils 13a each have a baffle 17 electrically connected to the end of the coil winding in the immediate vicinity of the respective fixed contact 10, which has the width of a switching knife 3 and is arranged tangentially to the movement path of the free end thereof.

2 shows the three busbars 9 and the quenching coils 13 arranged thereon via busbar sections 9a. These are fixedly arranged on the cross members 14, which also carry the fixed contacts 10, the cross members in turn via the supports 15, holding devices 16 and Struts 18 are held on the housing. It can be seen that the control panel I (circuit breaker) does not require a larger arrangement space in the housing 1 than the control panels II and III.

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 which is electrically coupled both to the start of the quenching coil 13a and to the cross member 14 and thus to the busbar 9.

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

In the illustrated embodiments of the switchgear assembly according to the invention, the free ends of the switch blades 3 can be provided with caps 22 for higher breaking currents to increase the resistance to erosion, and the fixed contacts 10 can be provided with erosion bars 23. The material of the caps 22 and the erosion bars 23 is more resistant to erosion than the base material of the respective contact 3 or 10 (FIG. 5).

Claims

claims

1 . SF6 gas-insulated switchgear for distribution networks with a gas-tight housing for several switchgear panels, each with a three-pole switch disconnector 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 Suitable for holding movable switch contacts and connecting cables and / or fuses bushings on the walls of the long sides of the housing and with switch shafts mounted on them and with busbars for the fixed contacts of phases L1, L2 and L3 and directly connected to the busbars Quenching devices for the individual phases, the quenching devices of the circuit breakers not used as transformer switches being quenching chambers provided with quenching plates, characterized in that the quenching devices for the phase n L l, L2 and L3 of the switch designed as a transformer switch with a switching contact arrangement corresponding to the other switches, quenching coils (1 3; 1 3a) are in an arrangement which fulfills the isolating path conditions when switched off and have means which ensure the switching capability,

the quenching coils (1 3) for the circuit breaker being arranged and designed in such a way

- That the coil axis (A) with the switch contact (3) in the switch-off position forms an obtuse angle (<) on the fixed contact side and the free end of the switch contact (3) lies in the area of the coil axis (A) and the coil radius is at least the distance between the switch contact (3) and the fixed contact (10)

- And that their fixed contact-side coil edge area is at a minimum distance from the fixed contact (1 0) and the free end of the moving switch contact (3),

and the quenching coils (1 3a) for the switch disconnector are arranged and designed in such a way

- That their coil axis (A) with the shade contact (3) in the switched-off position on the fixed contact side includes a right or obtuse angle (ß; v)

- And that they each have the base of the arc taking over guide element (1 7), which extends into the immediate vicinity of the fixed contact (1 0) and is arranged tangentially to the path of movement of the free end of the switching contact (3).

2. Switchgear according to claim 1, characterized in that the quenching coils (13; 1 3a) and the fixed contact (1 0) for the respective phase L1, L2 and L3 arranged on a cross member (14) connected to the respective busbar (9) are to which the movable switch contact (3) is aligned parallel in the switch-off position.

3. Switchgear according to Appendix 2, characterized in that the obtuse angle (a) is 1 650 to 1 750.

4. Switchgear according to claim 2, characterized in that the quenching coils (1 3a) are arranged and designed such that they enclose the fixed contacts (1 0), and that the guide element (1) is directed into the coil interior.

5. Switchgear according to claim 1, characterized in that the free ends of the movable switch contacts (3) with caps (22) and the fixed contacts (10) on the tear-off edge with erosion bars (23) are provided from a more erosion-resistant material than the respective contact material.

6. Switchgear according to claim 1, characterized in that the quenching coils (1 3; 1 3a) and the quenching chambers (1 2) with a in the at the rear (1 9) initially open housing (1) are inserted module which from the busbars (9), the fixed contacts (1 0), supports (1 5) for the cross members (14) and holding devices (1 6) for arrangement on the housing (1), and with cross members (14) attached to them, and that the three earthing contacts (8) belonging to the earthing device are attached to the switch shafts (5).