PL187349B1 - Gas-insulated switchgear employing sf 6 gas for power distribution 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 subject of the invention is a switchboard for distribution networks consisting of load-break switch bays with a combination of fuses - load-break switches or a circuit-breaker with a disconnecting section (load-break switch) designed to protect transformers.

The purpose of the light hook extinguishing devices located at the phases of the load-break switch or the power disconnector is to quickly extinguish the arc that occurs at them, which occurs during the switching off by opening the contacts and is caused by the evaporation of the last metal bridge caused by Joule's heat, in order to ensure the disconnecting capacity of the switch. In the case of alternating current, it depends on whether the charge carriers are effectively reduced in the short time between zero current flow and the rise of the return voltage.

In network distribution stations, as a rule, medium voltage switchgears are used with three switchgear bays, two of which are connected by a circular cable and one switchgear bay is equipped with high-voltage fuses or a power disconnector for the transformer branch.

From DE-OS 38 20 4899 there is known a switchgear with a system of gas-insulated switch disconnectors SFć, in which the load-break switches are placed in a hermetic casing filled with sulfur hexafluoride (SFæ), and which for each phase has a fixed movable contact, an earthing contact, and extinguishing device, and in which contacts of the same phases are fixed directly on the busbar and the extinguishing devices are placed on the busbar directly next to each of them.

In order to make such switchboards smaller and easier to install, in a development of the invention disclosed in DE 40 11 397 C2, the essential parts of the load-break switch are combined in one prefabricated sub-assembly, which is first inserted into the open housing and then fixed inside it. Earthing contacts belonging to the earthing device in this switchgear are attached to the shaft of the switch and can be easily mounted.

In addition to extinguishing devices consisting of extinguishing plates, other extinguishing devices for electrical switchgear are known, including extinguishing coils to which the resulting arc is commutated, as a result of which a current flows through the coils, which creates a magnetic field that causes the arc to spin. and eventually its extinction. Thus, EP 0 012 522 describes an electrical switchgear comprising quenching coils at fixed contacts. Also the subject of EP 0 021 577, EP 0 058 007 and EP 0 313 106 B1, as well as GB 2 196 794 and EP 0 676 782 are electrical switchgear devices with arc extinguishing coils as arc extinguishing devices.

In the case of the above-mentioned switchgears for distribution networks, insulated with SF ć gas, the load switch of one switchgear bay is provided with a fuse attachment containing high-voltage fuses with a jump-over pin, which in a given case are hermetic, and the load switch is equipped with a battery drive with a disconnection reservoir, which it is activated by means of the jump pin of one of the fuses through the disconnection rod. The system of extinguishing plates used as an extinguishing device has limitations also in terms of the breaking capacity (height of the rated fuse current) and the related fulfillment of the conditions of the disconnecting sections.

The task of the invention is to create a switchgear for distribution networks with a gas-tight housing insulated with SF gaz gas with increased disconnecting capacity with unchanged space requirements for the disconnector system, whereby both the load disconnectors and power disconnectors must be designed in such a way as to meet the conditions of disconnector sections, i.e. must show the required voltage withstand depending on the rated voltage. Moreover, both disconnectors must be shaped so as to ensure their breaking capacity, while they will control and extinguish the resolving electric arc in the shortest way.

The essence of the invention, which is a switchgear of distribution networks with a gas-tight enclosure insulated with SFæ gas for a unit, having one three-speed disconnector and one earthing device for switchgear bays, one of which is equipped with a load-break switch in the form of a transformer switch disconnector,

187 349 phases are connected with fuses or with a power disconnector, with bushings intended for mounting movable disconnecting contacts and for connecting cables and / or fuses with bushings at the longitudinal walls of the housing and with shafts of the connector placed on them and with busbars for fixed phase contacts LI, L2 and L3 and connected directly to the busbars with extinguishing devices for single phases, where the extinguishing devices for load disconnectors not used as transformer disconnectors are in the form of extinguishing chambers equipped with quenching plates, it consists in the fact that extinguishing devices for the phases LI, L2 and L3 shaped as The transformer switch disconnector of the disconnector with the arrangement of disconnecting contacts corresponding to the other disconnectors are quenching coils, while the quenching coils for power disconnectors are arranged and shaped in such a way that their coil axis (A) includes the disconnecting contact on the ski side in the disconnected position The obtuse angle a and the free end of the disconnecting contact is located within the axis of the coils (A), and the radius of the coils corresponds at least to the distance between the disconnecting contact and the fixed contact, while the edge area of the coils on the permanent contact side is in the minimum distance from the fixed contact and from the free end of the moving disconnecting contact, moreover, the quenching coils for the load disconnector are arranged and shaped such that the axis of the coils (A), together with the disconnecting contact on the side of the fixed contact, includes a right or obtuse angle β; a, and they have a conductor element embracing the bottom of the electric arc, which extends directly into the vicinity of the fixed contact and is tangential to the path along which the free end of the disconnecting contact moves.

It is advantageous if the quenching coils and the fixed contact for each of the phases L1, L2 and L3 are arranged on a cross member connected to a given busbar, to which a movable disconnecting contact is assigned rotatably.

It is also preferred that the obtuse angle α is 165 ° to 175 °.

It is also advantageous when the quenching coils surround the fixed contacts and when the conductive element points towards the inside of the coil.

It is also advantageous if the free ends of the movable disconnection contact have caps, and the fixed contacts at the arcing edges of the burner strips are made of a material more resistant to sunburn than the given contact material.

Moreover, it is advantageous if the extinguishing coils and the extinguishing chambers are combined into a single insertable subassembly in the rear-openable housing, which consists of busbars attached to them together with the fixed contact cross members, support insulators for the cross members and fastening devices for the arrangement. in the housing, and the three grounding contacts of the grounding device are attached to the shafts of the connector.

The switchgear in question includes numerous switchgear cubicles with three-pole load-break switches and an earthing device, one of which is equipped with a load-break switch shaped as a transformer switch-disconnector, whose phases are mixed with fuses, or it may have a power disconnector, and whose constant phase contacts LI, L2 and L3 are permanently connected to the busbars, at which extinguishing devices for individual phases are located, where the extinguishing devices for the LI, L2 and L3 phases formed as a transformer switch disconnector with the disconnecting contacts system corresponding to the remaining disconnectors are extinguishing coils and the extinguishing devices for the phases the remaining disconnectors are known extinguishing chambers with extinguishing plates.

The conditions of the disconnecting sections at the power disconnector are met and the measures for securing the disconnecting capacity - for the space requirements for disconnectors with quenching chambers and the corresponding arrangement of disconnecting contacts - are given if the extinguishing coils are arranged and shaped in such a way that their axis the coils, together with the disconnecting contact from the fixed contact side, has an obtuse angle, and the free end of the disconnecting contact in the disconnected position is located within the axis of the coils, and that the length of the radius

187 349 coils correspond at least to the distance between the disconnecting disconnecting contact and the fixed contact, and that the edge area of the coils on the fixed contact side is at a minimum distance from the fixed contact and from the free end of the moving disconnecting contact.

At the load-break switch, the conditions of the disconnecting sections are met, and the measures for securing the disconnecting capacity are given, if the quenching coils are arranged and shaped in such a way that their axis of coils, together with the disconnecting contact on the side of the fixed contact, at right angle or open, and the extinguishing coils have, in this case, a conductor element that reaches the bottom of the electric arc, which extends directly to the vicinity of the fixed contact and is arranged tangentially to the path along which the free end of the disconnecting contact moves. The use of a conductor element is of great importance in securing the breaking capacity of the load-breaker. The arc of light formed between the disconnecting knife and the contact is transferred along the conductor element to the coil. Due to the short distance, the arc remains very short, reaching the inner path of the extinguishing coil quickly and reliably. Thus, the task of the conductor element is to enable the arrangement of the coil, which in the case of a load-break switch is much smaller than in the case of a power disconnect, away from the contact of the busbar and, with this arrangement, to transfer the light arc to the extinguishing coil.

Arrangement of the extinguishing coils at the transformer switch disconnector allows to increase the disconnecting capacity of the switchgear with an unchanged arrangement space, while increasing the requirements for the combination of load-break switch fuses or the disconnection of short-circuit currents can be taken into account, which constitutes a significant technical progress.

The quenching coil and the fixed contact for each of the phases L1, L2 and L3 can hereby be deliberately arranged on the crosspiece, which is connected to the busbar for each phase and to which an objectively movable disconnection contact is assigned, such that it can be rotated. from the on position at the fixed contact to the disconnected position parallel to the crossarm and then into the earthed position.

The quenching coils can be arranged in such a way that their coils axis, together with the disconnecting contact in the disconnected position, on the side facing the fixed contact, an obtuse angle, preferably from 165 ° to 175 °, or will be arranged perpendicular to the in the disconnecting position of the disconnecting contact. In the last arrangement of the quenching coils, the fixed contact is located in the center of the quenching coil, and the conductive element points towards the inside of the coil.

In order to avoid intensive tanning at the edges of the contacts at higher disconnection currents (power disconnector), it is possible to provide the free ends of the movable disconnecting contacts and the arcing edges of the fixed contacts with caps and firing strips, which will consist of a material more resistant to tanning than the given contact material.

Finally, the extinguishing coils and extinguishing chambers can be combined into a single subassembly that can be inserted into a housing that can be opened from the rear to facilitate assembly and reduce the space required for assembly in the switchgear. This subassembly may consist of busbars attached thereto together with the fixed contact crosspieces, support insulators for the crosspieces and fixing devices for arrangement in the housing. The three grounding contacts of the grounding device are attached to the shafts of the coupler.

The subject matter of the invention, in an exemplary embodiment, is shown in the drawing, where fig. 1 shows a top view of the SF6 gas-insulated switchgear (load-break switch) according to the invention, fig. 2 - rear view of the switchgear (power disconnector), fig. 3 - one of Fig. 4 shows another embodiment of the phase of the load-break switch connected to the fuses, and Fig. 5 shows another embodiment of the fixed and open contacts of the power disconnector.

The switchgear shown in Fig. 1 consists of a gas-tight casing 1 in which there are three switchgear bays I, II and III, each with one three-pole disconnector.

187 349 loads and one earthing device. The switchgear bay I contains one load-break switch in the form of a transformer switch, whose phases LI, L2 and L3 are connected to fuses (not shown) via a bushing insulator 2.

Load-break switches have disconnecting knives 3 which act as disconnecting contacts, which are in the form of double knives. For the L2 phase, the disconnecting knives 3 rest directly on the respective bushing, for the LI and L3 phases, special supporting insulators of the disconnecting knives are used, which are connected to their respective bushings 2 by means of bearing elements (not shown). All bushings 2 are located on the front side 4 of the housing 1. The disconnecting knives 3 are actuated by the connector shaft 5 located at the walls of the housing 1, which is connected to the disconnecting knife 3 through the lever 6 and the connecting rod 7. The connector 5 is connected to the shaft of the connector 5 direct earthing contact 8.

The disconnecting knives 3 can have three positions. The given disconnecting knife 3, when in the on state, contacts with the fixed contact 10 permanently connected to the busbar 9. The on state is shown on the switchgear panel III. The given disconnecting knife 3, being in the disconnected state, assumes a position between the fixed contact 10 and the earthing contact 8. The disconnected state is shown on the switchgear panel II. The given disconnecting knife 3, when in the earthed state, is in contact with the earthing contact 8, which is shown in the switchgear panel I.

In the housing 1 there are three busbars 9, at which there are fixed contacts 10 for each of the phases L1, L2 and L3 of the load-break switch. At the busbars 9, there are also extinguishing devices for each of the phases LI, L2 and L3, which at the load-free phases of load-break switches of the switchgear panels II and III are in the form of quenching chambers 12 equipped with quenching plates, and at the load-free phases of the load-break switchgear cubicle I connected to with fuses, they are in the form of 13a extinguishing coils. The coils 13a and the fixed contacts 10 are arranged on a cross-arm 14 connected to the given busbar 9, against which the disconnecting knives 3, which are in the disconnected position, are directed parallel. The quenching coils 13a are arranged such that their axis A, together with the open contact 3 in the disconnected position, on the side facing the fixed contact 10 has an obtuse angle α of approximately 165 [deg.] (FIG. 2).

The extinguishing coils 13a and the extinguishing chambers 12 will be connected with busbars 9 arranged at the crosspieces 14 and permanently connected to the busbars 9 with fixed contacts 10, support insulators 15 for the crosspieces 14, fixing devices 16 and diagonal supports 18 for arrangement in the housing 1 into a single structural unit, slipping through the rear side 19 into the housing 1 before it is gas-tight closed.

Each of the quenching coils 13a has a conductor plate 17, electrically connected to the end of the coil winding, located in the immediate vicinity of a given fixed contact, the width of which is equal to the width of the disconnecting knife 3 and which is tangent to the path of its free end movement.

Fig. 2 shows three busbars 9 and the extinguishing coils 13 arranged next to them by busbar sections 9a. They are fixedly arranged at the crosspieces 14, which also hold fixed contacts 10, the crosspieces in turn being fixed in the housing by supporting insulators 15. , fastening devices 16 and diagonal supports 18. It can be seen that the switchgear cubicle I (power disconnector) does not require a larger layout space in the housing than the switchgear cubicles II and III.

Fig. 3 shows an enlarged view of the arrangement of the quenching coil 13a on one of the phases. The quenching coil 13a is held by a switch 20, which is electrically coupled both to the beginning of the coil 13a coil and to the crosspiece 14 and thus to the busbar 9.

Fig. 4 shows an alternative arrangement of the quenching coils for the same switchgear, in which the quenching coils 13a are arranged on the connector 21 in such a way that the axis of the coils A, together with the disconnecting knife 3 in the disconnected position, at the right angle β, constant the contacts 10 are surrounded by the quenching coils 13a. The quenching coils 13a have a fixed contact 10 electrically connected to their end in the immediate vicinity

187 349 of the coil winding, a conductor plate 17, the width of which is equal to the width of the disconnecting knife 3, and which is tangent to the path of its free end.

In the presented embodiments of the switchgear according to the invention, the free ends of the disconnecting knife 3 can be provided with caps 22, and the fixed contacts 10 with firing strips 23, in order to increase the resistance to firing at higher disconnection currents. The caps 22 and burner strips 23 consist of a material that is more resistant to fire. tanning than the given contact material 3 or 10, as shown in Fig. 5.

187 349

FIG 2

187 349

Ϊ6

187 349

187 349

FIG. 5

187 349

1/5

Publishing Department of the UP RP. Mintage 50 copies. Price PLN 4.00.

Claims (6)

Patent claims 1. Switchgear for distribution networks with a gas-tight casing insulated with SF6 gas for the unit, with one three-pole load break switch and one earthing device for switchgear bays, one of which switchgear bay is equipped with a transformer switch disconnector whose phases are connected to fuses, or with a power disconnector, with intended for mounting movable disconnecting contacts and for connecting cables and / or fuses with bushings at the longitudinal walls of the housing and with connecting shafts placed on them and with busbars for fixed phase contacts L1, L2 and L3 and connected directly to the busbars collective extinguishing devices for single phases, where the extinguishing devices of load disconnectors not used as transformer disconnectors are in the form of extinguishing chambers equipped with quenching plates, characterized in that the extinguishing devices for phases L1, L2 and L3 are The transformer switch of the disconnector with the arrangement of disconnecting contacts corresponding to the other disconnectors are the quenching coils (13; 13a), with the extinguishing coils (13) for power disconnectors being arranged and shaped such that their axis (A), together with the disconnecting contact (3) in the disconnected position, on the side facing the fixed contact, an obtuse angle (a ), and the free end of the disconnecting contact (3) is located within the axis of the coils (A), and the radius of the coils corresponds at least to the distance between the disconnecting contact (3) and the fixed contact, while the edge area of the coils on the fixed contact side is at a minimum distance from the fixed contact (10) and from the free end of the moving disconnecting contact (3), in addition, the quenching coils (13a) for the load-break switch are arranged and shaped such that the axis of the coils (A) includes the disconnecting contact in the disconnected position (3) on the side of the permanent contact, a right or obtuse angle (β; a) and they have a conductor element (17) that surrounds the base of the electric arc, which extends directly near the permanent contact (10 ) and is tangent to the track along which the free end of the disconnecting contact (3) moves. 2. Switchgear according to claim 3. The quenching coils (13; 13a) and the fixed contact (10) for each of the phases L1, L2 and L3 are arranged on a cross member (14) connected to a given busbar (9), which is assigned a rotatingly movable contact disconnector (3). 3. Switchgear according to claim The method of claim 1, characterized in that the obtuse angle (α) is 165 ° to 175 °. 4. Switchgear according to claim The method of claim 1, characterized in that the quenching coils (13a) surround the fixed contacts (10) and that the conductive element (17) points towards the inside of the coil. 5. Switchgear according to claim A device as claimed in claim 1, characterized in that the free ends of the movable disconnection contact (3) have caps (22) and the fixed contacts (10) at the arched edges of the burner strips (23) are made of a material more resistant to sunburn than the given contact material. 6. Switchgear according to claim A device according to claim 1, characterized in that the extinguishing coils (13; 13a) and the extinguishing chambers (12) are combined into one subassembly that can be inserted into the rear-openable housing (1), which consists of busbars (9) fixed to them together with crosspieces (14) of the fixed contacts (10), support insulators (15) for the crosspieces (14) and mounting devices (16) for arrangement in the housing (1), and the three earthing contacts (8) of the earthing device are attached to the coupler shafts (5).