Electrical switching system

#1. Field of the Invention

#The invention is directed at a switching system, preferably a medium-voltage switching system, comprising a power switch or load switch, a disconnecting switch, as well as a grounding switch configured as a vacuum switching chamber.

#2. The Prior Art

#Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the invention.

#In the drawings, wherein similar reference characters denote similar elements throughout the several views:

#FIG. 1 shows a schematic sectional representation of the components of a switching system according to the invention; and

#Referring now in detail to the drawings, FIG. 1 shows a power switch 1, a central switch 2 having a housing 3 that surrounds and encloses this switch, a disconnecting switch 4, a grounding switch 5, and a bus bar 6. All of these elements are components of a switching system, whereby the housing 3 with the central switch 2, the power switch 1, the disconnecting switch 4, and the grounding switch 5 form a switching unit. This switching unit can be disposed in a housing, not shown, which can be filled with an insulating gas that displaces air, N2 or extinguishing gas, particularly SF6 (sulfur hexafluoride). The switching system can therefore be a gas-insulated switching system, particularly for the medium-voltage range, whereby the switching system can furthermore also be an integral part of a switching station or a switching cell. In the present case, however, the switching system is configured as a switching system insulated with solid material, and particularly designed for the medium-voltage range.

#In FIG. 1, the central switch 2, which is configured to be electrically conductive, is in its normal position. In this normal position, it connects the connector contacts A of the power switch 1 and B of the disconnecting switch 4 with one another, so that an electrical connection line from the bus bar 6 through the disconnecting switch 4, the central switch 2 to the power switch 1 is switched through. The connector contact A stands in a conductive connection with a fixed contact 7 of the power switch 1. The power switch 1 is in its “open” position, so that its movable contact 8 is disposed at a distance from the fixed contact 7, forming a separation distance to the latter. By way of the movable contact 8, the power switch 1 is connected with an electrical outgoing circuit, symbolized by the arrow 9, for example in the form of cable connectors. In the closed position of the power switch 1, an electrical connection from the bus bar 6 to the outgoing circuit 9 would therefore be switched through in this normal position of the central switch 2.

#Both the disconnecting switch 4 and the grounding switch 5 are provided with a vacuum switching chamber 10, in each instance. The disconnecting switch 4 and the grounding switch 5 are furthermore configured with the same construction. Such a vacuum switching chamber 10 is shown in a schematic sectional representation in FIG. 2. The vacuum switching chamber 10 comprises a vacuum chamber 11, which is configured in the housing 12 of the vacuum switching chamber 10. A fixed contact 13 is disposed in the vacuum chamber 11, which contact forms an electrical connection from the vacuum chamber 11 out towards the outside. A contact tappet 14 projects into the vacuum chamber 11 through an opening disposed on the opposite side of the vacuum chamber 11, which tappet is provided with a switching contact 15 on the vacuum chamber side. In the chamber 11, the contact tappet 14 is disposed so that it can be displaced in a folded bellows cuff 16 made of metal, counter to the force of a pressure spring 17 disposed outside of the vacuum chamber 11, longitudinally-axially, whereby the folded bellows cuff 16 provides the required seal. The contact tappet 14 with the switching contact 15 therefore forms a movable switching contact that can be brought into contact with the fixed contact 13 configured as an additional switching contact, counter to the force of the pressure spring 17. On the outside, a connector contact 19 is configured and disposed on a pin-shaped head end 18 of the contact tappet 14, in the form of a cap. The connector contact 19 lies on a step on the contact tappet 14, and has a radial ring space for accommodating the pressure spring 17. When a force is exerted on the connector contact 19 in the direction towards the fixed contact 13, the contact tappet 14 can therefore be moved towards the fixed contact 13, counter to the force of the pressure spring 17, by way of the connector contact 19, so that the switching contacts 15 and 13 enter into contact with one another and form a line connection. The connector contact 19 forms the connector contact B for the disconnecting switch 4 and the connector contact C for the grounding switch 5. For the remainder, the grounding switch 5 and the disconnecting switch 4 are configured with the same construction.