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10/20 KV Medium voltage switchboards

General
Uni-MakMix medium voltage metal enclosed switchboards for indoor use are constructed by placing standardized units side by side in a coordinated way. Insulation of all live parts is guaranteed in air.
Construction and testing are carried out entirely in the factory. switchboards are preset for the
following apparatus:

  • HD4 type circuit-breakers in SF6 gas
  • SHS2 type switch-disconnectors and isolators in SF6 gas

Fields of application
Uni-MakMix switchboards are used in medium voltage secondary power distribution. In particular, they can be used for transformer substations and for control and protection of feeders and power transformers.

Normal service conditions
The rated service characteristics are guaranteed under the following limit conditions:
 - Minimum ambient temperature -5 C
 - Maximum ambient temperature +45
 - Maximum relative humidity 95%
N.B. For operation under other conditions, please consult us.

Main characteristics
Uni-MakMix switchboards are characterised by:

  • complete insulation in air of all the live parts of the switchboard
  • possibility of being placed against thewall
  • segregation between the busbar and feeder compartmentspossibility of constructingmany different solutions and simple extension of existing switchboards
  • easily accessible apparatus controls

personnel safety guaranteed by:

  • segregation of the compartmentswith IP2X degree of protection.
  • metal segregation and earthing guaranteed by the switch-disconnector / isolator stainless steel housing
  • insulating parts with large exhaust escape routes to guarantee insulation even in rooms with a high degree of pollution
  • earthling of both the structure and components.

On request, the switchboard can be fitted with a REF 542 Plus microprocessor unit. This unit
combines all the protection, control, measuring, etc. functions usually entrusted to several devices in a single piece of apparatus. The REF 542 Plus unit also makes it possible to dialogue with the installation control and automation systems, allowing plant data acquisition and processing.

Surface treatment

The units are made of pre-galvanized sheet. The doors and front panels are painted grey RAL 7035. The surface appearance is semi gloss. The standard version switchboards have their sides made of pre-galvanized sheet (on request, RAL 7035 painted versions are available).

Degrees of protection
IP2X inside the switchboard
IP3X on the external housing.

Quality Assurance system
Complies with ISO 9001 Standards, certified by an independent organization.

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 bottom 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 bus bar 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.


Bus bar compartment (A)
This contains the main bus bar system. The bus bars,made of electrolytic copper, are fixed to the terminals of the
insulation isolator or of the switch-disconnector. Insulation is guaranteed in air.

Feeder compartment (B)
This is normally segregated from the bus bar compartment by means of an isolator or a switch-disconnector.
It contains the apparatus shown in the figure below.

Auxiliary circuits
A box containing all the low voltage apparatus normally used can be provided in front of the bu sbar compartment.
In particular:
- terminal boxes,wiring ducts and cables to connect the auxiliary circuits of the unit;
- auxiliary accessories of the circuit-breaker and unit (measuring instruments, protection relays, control and signaling devices, fuses, auxiliary circuit protection circuit-breakers, etc.)
Cable passage for inter-panel connections is made by means of special holes provided in the walls of the box itself.

Installation room
The installation room must be prepared according to the switch-board dimensions and version.
Observance of the distances indicated guarantees a regular operation of the apparatus.