PAK SERIES – Reinforced Substation for Tunnelling

PAK SERIESPAK series, medium voltage electrical mobile substation for tunnelling and mining installation, is a reinforced unit, that can be installed on a truck, skid mounted or placed on a wagon, for easy handling in the tunnel.

Extremely robust and resistant to heavy mechanical stress, PAK substation can operate in extreme environmental conditions.

It conforms to European Standard IEC, Tunnelling and Mining Rules.


PAK substation is manufactured with 5 and 3 mm thick cold-worked and continuous welded steel plate.

Substation doors are mounted by inox steel hinges. Bolt, screws and mechanical devices have anti-corrosion treatment.
Enclosure, with closed door, is IP549.


Substation is painted and finished to the following specification:

  • sheet degreasing with synthetic thinner
  • sanding with scotch-brite 3M for zinc passivated steel supports
  • one coat antirust epoxide primer, 25 micron thick
  • two coats epoxide enamel, 60 micron thick
air insulated switch disconnector
SIZE 10(LxDxH) mm 3050 x 1650 x 950100 ÷ 250 KVA
SIZE 11(LxDxH) mm 3250 x 1650 x 950315 ÷ 630 KVA
SIZE 12(LxDxH) mm 3550 x 1650 x 950800 ÷ 1000 KVA
tee switch
SIZE 13(LxDxH) mm 4350 x 1650 x 950100 ÷ 250 KVA
SIZE 14(LxDxH) mm 4550 x 1650 x 950315 ÷ 630 KVA
SIZE 15(LxDxH) mm 4850 x 2000 x 950800 ÷ 1000 KVA
gas (SF6) insulated switch disconnector
SIZE 20(LxDxH) mm 3350 x 2000 x 1100100 ÷ 250 KVA
SIZE 21(LxDxH) mm 3550 x 2000 x 1100315 ÷ 630 KVA
SIZE 22(LxDxH) mm 3850 x 2000 x 1100800 ÷ 1000 KVA
SIZE 23(LxDxH) mm 4050 x 2000 x 11001250 KVA
tee switch
SIZE 24(LxDxH) mm 3850 x 2000 x 1100100 ÷ 250 KVA
SIZE 25(LxDxH) mm 4250 x 2000 x 1100315 ÷ 630 KVA
SIZE 26(LxDxH) mm 4350 x 2000 x 1100800 ÷ 1000 KVA
SIZE 27(LxDxH) mm 4550 x 2000 x 11001250 KVA

Medium Voltage Switchboard

The medium voltage switchboard is installed in a separate section segregated from the LV side, which includes:

  • an earthing switch disconnector on the incoming line
  • an on load switch disconnector with tripping coil combined with current limiting fuse (switch fuse combination)
  • an earthing switch disconnector on the outgoing line


To comply with current standards, different types of transformer can be provided with the substation according to customer requirements:

  • Cast resin transformer (50-1250 KVA)
  • Silicon oil transformer (50-1250 KVA)
  • Dry-type transformer (50-1250 KVA)

Low Voltage Switchboard

The low voltage switchboard is fitted into a separate section segregated from the MV side. It includes the main circuit breaker to protect the transformer against short circuit, overload and earth-fault.

The design arrangement of the LV utilities is manufactured to suit customer specifications and can include moulded case circuit breaker (MCCB), load break disconnector combined with current limit fuses, earth leakage protection, starters, small PLC and measuring devices as well as automatic power factor correction unit.

Dielectric withstand voltageKV283850
Impulse withstand voltageKV6075125
Rated primary voltageKV101520
Rated frequencyHz50/6050/6050/60
Rated Secondary voltageV400400400
Auxiliary voltageVac/Vdc230/24230/24230/24
Transformer capacityKVA up to 1250
Enclosure (with cabinet closed)IP549
Operating ambient temperature-10 / +40ºC
Humidity (non condensing)Rh 85%