DE10219299B3 - Gas-insulated single-pole switching device has load breaker and earthing switches within gas-tight housing having cylindrical section fitted with at least one concave end wall - Google Patents

Abstract

The switching device (1) has an electrically-conductive gas-tight housing (3) filled with an insulation gas having a cylindrical section (6) fitted with 2 end walls (4,5), containing load breaker and earthing switches (14,25), with insulation of the housing relative to the switches and the electrical connections (2,10,13,15,16). The load breaker switch has a switch mechanism with a linear displacement in the longitudinal direction of the housing cylindrical section, at least one end wall of the housing bent outwards with a concave curvature.

Description

The invention relates. a single pole Switching unit of a switchgear for switching an electrical Current, especially in the medium voltage range, with an electrical conductive gas-tight housing, that infects with an insulating gas is and cylindrical Has pipe sections and end walls connected to them, with switches for interrupting a flowing current, for providing a isolating section and for earthing the switchgear, with electrical conductive connecting means and with bushings for isolating the housing from the Switches and lanyards.

Such a switching unit is out published in 1996 Catalog HA 3515 from Siemens AG known. The switching units disclosed there a multi-pole switchgear are each made of pipe sections composed, in the interior of an interrupter unit for interrupting a current flow and a three-position switch that switches off to provide a required separation distance and to the earth end Switching unit are arranged. Furthermore, connecting means for electrical connection of the switches with each other and for closing and lead away of a current to be switched. The lanyards serve also the holder of the interrupter unit and the three-position switch on the housing by means of an implementation. The interrupter unit is designed as a push switch and has one along of the assigned pipe section movably guided moving contact. The Switching movement of the three-position switch is, however, transverse to that directed each pipe section, so that one of the respective switching position of the three-position switch dependent inhomogeneous Distribution of the electric field between those with high voltages affected components inside the housing and the ground potential lying housing wall established.

To breakdowns, especially on Due to such inhomogeneities, to be avoided is the housing with sulfur hexafluoride disclosed there filled, because of its electronegative property as high quality Insulator has prevailed in practice as a protective gas. Because polluting Properties of this gas have so far not been completely excluded can, however, it is desirable to be able to switch to other environmentally friendly gases if necessary.

As an alternative to sulfur haxafluoride comes For example, nitrogen is considered as one of the main components the atmospheric air, also has electronegative properties. However the dielectric strength of nitrogen and others so far known insulating gases or insulating gas mixtures against sulfur hexafluoride reduced. For example, voltage flashovers to avoid nitrogen-insulated switchgear or switchgear, are therefore compared to comparable sulfur hexafluoride-insulated systems larger distances between metallic components different potential required. This increases the Installation space of such switching units is considerable.

Although the dielectric strength can of insulating gases or insulating gas mixtures also by increasing the Gas pressure in the housing of the Switching unit or switchgear can be improved. Such an increase in pressure makes however one opposite the elevated Pressure mechanically stable and gas-tight housing required. The requirement the mechanical pressure resistance was previously met with the help of thicker housing walls. Such Switching units and thus the switchgear formed from them however, are heavier and more expensive to manufacture.

A single-pole switching unit is known from WO 01/93393 A1 a switchgear known, which is a gas-tight, with sulfur hexafluoride filled Switching chamber has. There is an interrupter unit in the switching chamber provided for switching an electric current at high Tensions is established. To determine the amount of sulfur hexafluoride to be used to limit the switching unit shown there continues via a chamber filled with nitrogen, in which a surge arrester cooperating with the interrupter unit located. That filled with nitrogen casing has an internal pressure between 4 and 6 bar and consists of two axially opposite each other End walls and a cylindrical side wall connecting them. One of the end walls is concavely curved outwards. The switching unit disclosed there However, it takes up a lot of space and is therefore of limited use in practice.

The EP 0 190 437 A1 discloses a metal-encapsulated gas-insulated switchgear with a circuit breaker and a disconnector, which are each arranged in a gas-filled housing. These housings are set up separately from one another and form separate gas volumes.

The EP 0 872 934 A1 discloses a circuit breaker arranged in a switch housing, the end faces of which are curved. A disconnector arranged in the housing is not disclosed.

In the DE 41 23 710 A1 a vacuum circuit breaker arranged in a cubic metal encapsulated housing is shown.

WO 01/50563 A1 describes a switchgear assembly which has a circuit breaker and a combined disconnector and earthing switch which are arranged laterally offset from one another in a cross-sectional view. Here is the switch housing cubic.

In the CH 559 977 A4 discloses a switchgear assembly with a circuit breaker which is arranged in a metal-encapsulated housing and is connected to a busbar via a conductor. The circuit breaker is used to interrupt a current flow, whereby the conductor can be separated from the busbar by rotating a shaft and takes over earthing functions in a separate position.

The DE 31 12 776 C2 discloses a switchgear assembly with a cylindrical housing and a cylindrical vacuum circuit breaker arranged coaxially in the housing, the housing being filled with insulating oil and having flat-side end walls.

In the DE 30 35 381 A1 describes a metal-encapsulated gas-insulated switchgear assembly with switches arranged one behind the other in a housing of the switchgear assembly, the housing having concavely curved end faces.

The DE 195 02 061 A1 discloses a switchgear with a circuit breaker and a circuit breaker, which are arranged in series, the circuit breaker being designed as a rotary switch.

The DE 199 58 646 C2 relates to a hybrid circuit breaker and the DE 40 27 723 A1 illustrates a switch disconnector with a vacuum interrupter.

The object of the invention is a To provide switching unit of the type mentioned in the Maintaining the compact design and low manufacturing costs allows the use of a protective gas with a high internal pressure.

This object is achieved according to the invention solved, that the switches for interrupting the power and for providing a isolating section combined in a circuit breaker are, the circuit breaker a push switch with a straight line Switching movement is and the pushing movement of the circuit breaker longitudinal of the pipe section is directed in which the circuit breaker is arranged, wherein at least one of the end walls is concavely curved outwards is.

To ensure the pressure resistance of the gas-tight housing improve, according to the invention, all side and almost all or all of the end walls of the housing are curved outwards, so that the most pressure-stable design of a housing, namely a ball, is possible come close, but at the same time with regard to several poles the entire switchgear and thus with regard to side by side switching units to be assembled, little space is required. Around to further improve the compactness of the respective switching unit, are all in the case arranged switch designed as a push switch, the switching movement straight and longitudinal of the assigned pipe section is aligned. In this way becomes an essential even with different switching positions even distribution of the electrical field between the housing and the one on a strong deviating electrical potential switches and connecting means generated. This even field distribution allows a reduction according to the invention the radial distance between the respective pipe section of the housing and the switches and lanyards. Circuit breakers are according to the invention and disconnector combined into one component. Therefore, one can second lever arrangement for transmission a drive for the disconnector is dispensed with and the compactness of the system can be increased.

The insulating gas expediently has a pressure between 3 and 6 bar. The setting of this pressure range is particularly suitable for the use of nitrogen in medium voltage technology advantageous as an insulating gas. According to the invention, however, other insulating gases can also be used or insulating gas mixtures such as mixtures consisting of Nitrogen and sulfur hexafluoride in this or other pressure ranges be used.

According to an expedient further development the circuit breaker has a cylindrical gas-tight vacuum chamber on, in which a fixed fixed contact and in this regard longitudinally movable guided Protrude into the moving contact. The mobility of the moving contact becomes ensured by a metal bellows, the one hand with the moving contact and on the other hand gas-tight with the vacuum chamber wall connected is. The moving contact is used to switch on the current introduced to the fixed contact and pressed against it with a certain pressure. The The current flow is interrupted by a longitudinal displacement of the Moving contact until this is sufficient in an interrupt position is far from the fixed contact. To transfer to a disconnected position, in which the circuit breaker has the necessary dielectric strength provides the switching unit, the stroke is the distance of the Moving contact from the fixed contact still in the same direction elevated. By using a circuit breaker, the use is an additional disconnector in addition to a pure breaker unit, making the compact design of the switching unit and thus that of several switching units existing switchgear is improved.

In an expedient further development, the switch for earthing the switching unit is an earthing vacuum switch, which has a gas-tight vacuum chamber as an encapsulation, into which a stationary fixed contact and a moving contact in this regard extend in a longitudinally movable manner. The Mobility of the moving contact, which is at earth potential, is ensured by a metal bellows, which is connected gas-tight to the moving contact on the one hand and to the vacuum chamber wall on the other hand. To ground the switching unit, the moving contact is only brought into contact with the fixed contact, which is electrically connected to the other switches and connecting means. The earthing vacuum switch switches when de-energized. In its manufacture and assembly, cost considerations can therefore come to the fore.

In a preferred embodiment the grounding vacuum switch is partially located outside the gas-tight housing and by means of an appropriate implementation held this, the connecting means a contact pin have out of the housing by performing extends through and with the fixed contact of the grounding vacuum switch is firmly connected. By this measure, the switching movement is Earth the switch unit outside of the housing relocated. The elaborate movable storage of tension Components inside the housing deleted Consequently. The earthing vacuum switch is isolated using the implementation and thus by means of a solid that is directly on the switch is applied, so that the compactness of the switching unit is increased.

The connecting means expediently comprise a role contact to lead a contact pin and a busbar, the roller contact firmly with the busbar and the contact bolt with a moving contact a switch is connected. The roller contact has a hollow cylindrical one Pipe socket on which contact rollers are provided, on the one hand on the contact bolt and on the other hand on the inner wall of the pipe socket issue. The facing the associated pipe section of the housing outer wall the roller contact is therefore essentially rotationally symmetrical, so that through this constructive measure an exact adjustment of the Pipe section to the roller contact with the same radial Distance of the equipotential surfaces is enabled.

In a further development according to the invention is in the housing a gas-permeable support plate made of an insulating material provided with the associated pipe section and a connecting means is firmly connected. In this way is stability of the housing further increased.

With an appropriate further development in this regard current and / or voltage sensors are provided in the support plate, whose measurement signals over suitable means of transmission directed outside become. In this way, the current state of the switching unit can be monitored become.

Further expedient configurations and advantages the invention are the subject of the following description of Embodiments of the Invention with reference to the figure of the drawing.

1 shows an embodiment of the single-pole switching unit according to the invention of a multi-pole switchgear in a sectional side view.

1 shows an embodiment of the single-pole switching unit according to the invention 1 over a partially solid-insulated busbar 2 with another single-pole switching unit 1 connected is. The switching units 1 form the poles of a switchgear, the number of which corresponds to the number of phases to be switched. The more detailed single-pole switching unit 1 has a gas-tight housing filled with nitrogen 3 that has an upper end wall 4 and an axially opposite lower end wall 5 having. Between the upper end wall 4 and the lower end wall 5 is a cylindrical pipe section 6 arranged, which extends in the axial or vertical direction.

In the area of the upper end wall 4 protrudes the live busbar 2 in the housing 3 into it, with two bushings lying opposite each other and made of cast resin or other insulating material 7 the mechanical fastening of the busbar 2 on the housing 3 and at the same time enable the electrical insulation of these two components from one another. On that of the neighboring switch unit 1 opposite side of the housing 3 protrudes the busbar 2 with its free end from the implementation 7 and is due to an appropriate solid insulation 8th shielded from the outside. The busbar composed of individual parts 2 can, however, be extended if necessary.

The two opposite bushings 7 are not directly on the pipe section 6 attached. Rather, there are opposite pipe lugs 9 recognizable, the busbar openings through the bushings 7 are each sealed gastight. The pipe lugs 9 allow the use of bushings 7 with a flat and thus from the radius of curvature of the pipe section 6 independent mounting surface.

On the busbar 2 is related to the pipe section 6 a roller contact arranged in a central location 10 intended. The role contact 10 has a hollow cylindrical pipe socket 11 on, in the contact roles 12 are provided on the one hand in the pipe socket 11 protruding contact rod 13 and on the other hand on the inner wall of the pipe socket 11 issue. The role contact 10 thus acts as an electrically conductive guide for the contact rod 13 in the axial direction and thus in the longitudinal direction of the assigned pipe section 6 ,

The contact bar 13 is at her from role contact 10 opposite end firmly with an invisible moving contact of a circuit breaker 14 connected. The moving contact protrudes into an evacuated gas-tight vacuum chamber of the circuit breaker 14 into which a stationary fixed contact, not shown in the figure, is also arranged. The fixed contact is with a holding rod protruding from the vacuum chamber 15 firmly connected, which becomes a connection module 16 extends from the ring-shaped cable connections 17 as well as cross connections 18 is composed. The cable connections 17 are firmly in the lower end wall 5 integrated, with an insulating material 19 , such as cast resin, the necessary insulation of an electrical with the cross connections 18 connected cable contact piece 19 opposite the lower end wall 5 provides.

The connection module 16 is in a pipe section 20 of the housing 3 arranged, the circumferentially opposite the pipe section 6 is expanded so that a shoulder area 21 is trained. The diameter of the expanded pipe section 20 depends on the number of required cable connections 17 and thus dependent on the desired distribution options.

To stabilize the handrail 15 inside the case 3 as well as to stabilize the housing 3 itself is over the shoulder area 21 a support plate 22 provided on the one hand with the wall of the pipe section 6 and on the other hand with the handrail 15 is firmly connected. The support plate, which consists of an insulating material such as cast resin, has recesses 23 on that a free passage of the nitrogen gas and thus a pressure equalization within the housing 3 enable. Inside the support plate 22 current and / or voltage sensors, not shown in the figures, are arranged, which monitor the operating state of the switching unit 1 enable.

Above the support plate 22 is also a rupture disc 24 provided, by which a predetermined breaking point is defined, which in the case of an internal gas pressure in the housing 3 that exceeds a maximum limit.

The rupture disc 24 Opposite is a grounding vacuum switch 25 recognizable by means of an insulating bushing 7 outside of the pipe section 6 is held. For this purpose, the bushing is made of cast resin, for example 7 an elastic cuff 32 Made of silicone rubber (EPDM), the one the grounding vacuum switch 25 enclosing pipe approach.

The grounding vacuum switch 25 has a housing under vacuum 26 on, in which a fixed fixed contact 27 and a moving contact guided in a straight line in this regard 28 protrude. A metal bellows 29 to seal the housing 25 is both on the moving contact 28 on the housing as well 26 attached.

For earthing the switching unit 1 will be the circuit breaker first 14 brought into the disconnected position beyond the break position. Then the moving contact is at ground potential 27 of the grounding vacuum switch 25 with the fixed contact 28 contacted. The earthing vacuum switch can be driven mechanically or electrodynamically or by hand.

To drive the circuit breaker 14 is a swivel lever 30 provided on the housing 3 about a pivot axis 31 is pivotally mounted, with a metal bellows 29 to seal the housing 3 is used. The swivel lever 30 is only mechanical, but not electrical with the contact rod 9 connected. Due to the movement generated by a mechanical or electrodynamic drive unit (not shown), the lever arm is thus moved 30 an axial stroke movement of the contact rod 13 generated.

Claims (8)

Single-pole switching unit ( 1 ) a switchgear for switching an electrical current, in particular in the medium voltage range, with an electrically conductive gas-tight housing ( 3 ), which is filled with an insulating gas and cylindrical pipe sections ( 6 . 20 ) and end walls connected to them ( 4 . 5 ), with switches arranged in the housing ( 14 . 25 ) to interrupt a flowing current and to provide a isolating section as well as with a switch for earthing the switching unit ( 1 ), with electrically conductive connection means ( 2 . 10 . 13 . 15 . 16 ) and with bushings ( 7 ) to isolate the housing ( 3 ) opposite the switches ( 14 . 25 ) and the connecting means ( 2 . 10 . 13 . 15 . 16 ), characterized in that the switches for interrupting the current and for providing a isolating section in a power isolating switch ( 14 ) are realized in combination, the circuit breaker ( 14 ) is a push switch with a linear switching movement and the push movement of the circuit breaker ( 14 ) in the longitudinal direction of the pipe section ( 6 ) in which the circuit breaker ( 14 ) is arranged, at least one of the end walls ( 4 . 5 ) is concavely curved outwards. Single-pole switching unit ( 1 ) according to claim 1, characterized in that the insulating gas has a pressure between 3 and 6 bar. Single-pole switching unit ( 1 ) according to claim 1 or 2, characterized in that the switch for grounding the switchgear is a grounding vacuum switch ( 25 ) which is a gas-tight vacuum chamber ( 26 ) as encapsulation, into which there is a fixed contact ( 27 ) as well as a longitudinally moveable moving contact ( 28 ) extend. Single-pole switching unit according to claim 3, characterized in that the earth vacuum switch ( 25 ) at least partially outside the housing ( 3 ) is arranged. Single-pole switching unit ( 1 ) according to one of the preceding claims, characterized in that the connecting means a roller contact ( 10 ) for guiding a contact rod ( 13 ) and a busbar ( 2 ), with the roller contact ( 10 ) firmly with the busbar ( 2 ) and the contact rod ( 13 ) with a moving contact of a switch ( 14 ) connected is. Single-pole switching unit ( 1 ) according to one of the preceding claims, characterized in that in the housing ( 3 ) a gas-permeable support plate ( 22 ) made of an insulating material is provided, which with the associated pipe section ( 6 ) and a lanyard ( 15 ) is firmly connected. Single-pole switching unit according to claim 6, characterized in that in the support plate ( 22 ) Current and / or voltage sensors are arranged. Single-pole switching unit according to one of the preceding claims, characterized in that in the housing ( 3 ) a rupture disc ( 24 ) is provided.