Transpower’s self-contained mobile substation on the road

New Zealand’s state-owned electric power transmission corporation, Transpower, has completed its $6 million state-of-the-art mobile substation.

The 110/33-22-11kV, 15/18MVA, two-trailer unit – which was custom designed and built by Mitton ElectroNet – is the largest mobile substation in the country.

The substation is self-contained with up to three feeder breakers that are cable connected to local supply company networks.

The mobile project also has its own 33kV feeder cables, local service supplies, protection systems, revenue metering and SCADA via cellular radio or satellite link.

The mobile facility will be used during maintenance or upgrade work at 110kV substations, where it completely bypasses the host substation so that security of supply can be maintained to communities and townships.

The mobile substation provides a number of benefits for a number of small communities around New Zealand that are fed from a single transformer or transmission line with no back up supply when maintenance is required. The use of the mobile substation removes the need for day-long power outages for these remote, largely rural communities.

The 70 tonne specialised compact equipment and transformer took 12 months to design and build. It is the fourth mobile substation Mitton ElectroNet has designed and incorporates two 17m trailers so it can be transported around the country.

The substation provides greater flexibility for maintenance work and helps to improve safety as it removes the time pressures to complete work to restore power within a required time window.

It can also be used in emergency situations where power supply has been affected by unforeseen events and repairs cannot be made quickly.