Mobile Substation Design

Mitton ElectroNet provided the lead design expertise on the 110/33-22-11 kV mobile substation project; the largest mobile substation built in New Zealand. The main usage of a mobile substation is to prevent long power outages when activities such as maintenance and protection ​upgrades are taken place. It can also act as a spare transformer when power outage occurs due to faults or damage in substations. The mobile substation is suitable for smaller substations in rural areas as it handles up to 20 MW of load; equivalent to about 5,000 households.

Project Overview and Design

The mobile substation design consists of two trailer units (MS1 & MS2); MS1 contains high voltage (HV) equipment such as transformers, whereas MS2 contains low voltage (LV) equipment such as the control room. The challenge for Mitton ElectroNet’s Draughting team was to create detailed drawings of MS1 and MS2. 


3D models of both trailers units were created using AutoCAD. The models are clearly labeled and informtive equipment schedules are provided. The drawings also demonstrate how the mobile substation will present in services and in transport position. From the 3D models, plan view and side view of the design are created and fully dimensioned to build the trailers.

Project Outcome

Both MS1 and MS2 of the mobile substation design were accurately created. The design has been built completely and has already gone through a few successful maintenance missions around New Zealand.