Client Mainpower

Completed May 2022

Location Christchurch

Scope & Scale

  • The substation was a greenfield development for a new 66kV to 11kV substation, adjacent to an existing, to service Rangiora power supply.  Scope included.
  • Site establishment and enabling works
  • Earthworks for basement excavation driveway and re-contouring the site
  • Construction of two-storey (142m2 each) switchroom building, with loading and access platforms including all building services (ventilation, heating, cooling, plumbing, lighting/LV power supply, fire detection, security system, ducting installation
  • Formation of two (80m2) transformer bays with bund walls and drainage and construction of 6.5m high fire wall (electrical equipment and transformer installation by others)
  • Concrete works (entry slab/platforms to basement, landing platforms and stairs to the switchroom, pavements)
  • Civil works including stormwater and subsoil drainage, wastewater, and stormwater pump stations, (including rising main to existing sanitary sewer connection), connection and pipework for water supply, fencing

Performance

The site experienced challenging groundwater conditions requiring a comprehensive management plan and discharge system to prevent groundwater being drawn from a neighbouring sawmill with contaminated ground issues. (Water had to be regularly sampled to ensure no contamination had been drawn across)

The project required close cooperation with Transpower who managed the existing neighbouring site.

The project called for significant coordination and interface with Mainpower’s HV electrical contractor. The building and transformer pads had to be ready to receive electrical/switchgear installations and transformers.

HRS direct labour was employed for traditional carpentry and concrete works.

Programme:  Unfortunately, the programme of works was frustrated by Resource Consent delays, COVID lockdowns, separate contractor delays, and adverse weather impacting on programme milestones and original completion date.

Health & Safety: No injury or lost time incidents recorded.

Budget: Achieved including approved variations.