The specified switchgear is a factory-assembled, type-tested, single-pole metal-enclosed, gas-insulated medium-voltage switchgear with metallic partitions in panel-type construction.

The switchgear must be available in the double-busbar switchgear version.

The following panel types must be available as a double-busbar switchgear up to a maximum rated continuous current for the busbar of 2500 A:

• Circuit-breaker panel with vacuum circuit-breaker
• Bus sectionalizer with vacuum circuit-breaker
• Bus coupler
• Cable connection panel
• Metering panel
• Dummy panel

The panel depth shall be identical regardless of the rated current.

Through an identical panel spacing and the use of as few standard components as possible, the uniform panel design shall be specific to the switchgear.

The panel design shall include the following functional modules:

• Single-pole enclosed busbars with modular switchgear housings made of corrosion-proof aluminum alloy
• Pole housings with vacuum circuit-breakers and three-position disconnectors

• Cable compartment with maintenance-free inside-cone plug-in system or fully insulated bar connection
• Low-voltage compartment
• Panel enclosure

The complete switchgear has to be designed safe-to-touch, including the busbar and cable compartments.

The busbars must be of flat or profile copper and always be designed without transverse partition in the respective phase. They can consist of single parts bolted together panel by panel. The busbar connection shall be bolted tight with a defined tightening torque. If necessary, suitable compensators must be installed in order to absorb thermal expansion and contraction movements. High-quality cast resin components must be used for supporting the conductor; they must feature a high tracking resistance.

The busbars shall be located in a metal-enclosed compartment with complete gas insulation (without plug connections or adapters), and the switchgear must be extensible at both ends of the busbar. Optionally, extensibility without interruption of operation can be provided.

Switchgear assemblies with a rated busbar current of up to and including 2500 A are to be designed with copper bar connections in two busbar housings (twin busbar).

It must be possible to earth all busbar sections in a make-proof way.

The vacuum circuit-breaker and the three-position disconnector for CLOSE, OPEN, EARTHING or READY-TO-EARTH operations must be maintenance-free as switching elements including the operating mechanism.

The three-position disconnector shall reduce the functional elements inside the enclosure and serve for make-proof earthing together with the circuit-breaker.

The switching devices are to be mounted in the enclosure independently of climate and environment.

To reduce the number of mechanical parts inside the enclosure, the operating mechanism shafts shall be arranged outside the enclosure.

The gas-filled housings shall be made of a corrosion-proof aluminum alloy. Insulation of live parts against the earthed enclosure is provided by the insulating gas.

The cable connections of the 3 phases shall be arranged at the same level, horizontally one behind the other. It shall be possible to use safe-to-touch cable plug-in sealing ends. The inside-cone system according to IEC 50181 is to be used.

The low-voltage compartment is to be located at the front. It has to be removable.

The wiring of the control and signaling circuits is to be designed with a flexible wire of 1.0 mm²; current transformer circuits with 2.5 mm². The control and signaling circuits are to be combined in functional groups and executed through plugs connected to terminal strip.

The bus wires shall be pluggable from panel to panel.

The switchgear must be resistant to internal faults according to IEC 62271-200 and IEEE Std C37.20.7™-2007 for short-circuit currents up to a maximum of 40 kA (1 sec).