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» MV Compact Switchgears




 

UnimixMV Compact Switchgears 

Unimix compact medium voltage metal enclosed switchgear for indoor use

is constructed by placing standardized units side by side in a coordinated

way. Insulation of all live parts is guaranteed in air. Construction and

preset for the following apparatus: testing are carried out entirely in the factory. Compact switchgear is

 

VD4 type vacuum circuit-breakers

HD4 type circuit-breakers in gas

SHS2 type switch-disconnectors and isolators in gas

Compact switchgear is used in medium voltage secondary power

distribution. In particular, it can be used for transformer substations and for

 control and protection of feeders and power transformers.

 

UniMix switchgear in the arc proof version guarantees maximum personnel

safety even in the case when an internal arc takes place inside the unit. The

switchgear is built to resist the overpressures caused by the internal arc and

 suitable ducts convey the gases produced by the arc outside the switchgear.

 

Compartments

The structure of each unit is entirely constructed using pre-galvanized metal

sheets. Each unit consists of several compartments with metal segregations between

 them. Each unit is preset with special holes for fixing to the floor and is provided with back

 closure fitted with special openings for medium voltage and auxiliary circuit cable passage. All the units

 fitted with a door have an interlock which only allows door opening under safe conditions. The busbar compartment

 is accessed from the roof or from the front by dismantling the special metal cover. There is a special metal wiring duct in each unit to segregate the low voltage circuits from the medium voltage circuits.

Busbar compartment (A)

 

This contains the main busbar system. The busbars, made of electrolytic copper, are fixed to the terminals of the insulation isolator or of the switch-disconnector. Insulation is guaranteed in air. The three busbar current transformers can be applied in the busbar compartment or, alternatively, three busbar voltage transformers. In the former case, the switchgear must be made up of at least three panels, and in the latter by at least two panels.

Feeder compartment (B)

This is normally segregated from the busbar compartment by means of a rotary insulation isolator or a switch-disconnector. It contains the apparatus shown in the figure below. 

 

1 Circuit-breaker

2 Isolator

3 Current sensors

4 Switch-disconnector

5 Fuses

 

6 Earthing switch