Grid reconfiguration - Otahuhu 110 kV bus

01 May 2020

Under the Electricity Industry Participation Code, Transpower is required to demonstrate a net benefit for any temporary or permanent reconfiguration of the grid.

Project Grid reconfiguration details Documentation Assessment
Otahuhu 110 kV bus With the retirement of generation and the installation of new equipment, the impact of faults on the network has reduced, meaning that the bus split previously in place between the two 110 kV electrical buses at Otahuhu substation is no longer required. Supporting information [ pdf 169.82 KB ] May 2020
Bells Pond transmission constraint - contingency plan

This document informs stakeholders of our intention to reconfigure the Lower Waitaki Valley 110 kV network, by introducing a system split  at Studholme, in the event that:

  • there is higher than anticipated peak load in the Lower Waitaki region, and/or
  • demand response is insufficient to keep line loadings within the circuit rating
Supporting information [ pdf 643.75 KB ] October 2016
Arapuni Bus Split Retention

This document presents analysis supporting our intention to:

• Retain the Arapuni 110 kV bus-split

• Install a Special Protection Scheme (Arapuni–Kinleith Runback Scheme) and

• Implement variable Line Ratings on the Kinleith–Tarukenga circuits

Supporting information [ pdf 448.75 KB ] June 2016
Arapuni Bus Split Closure Update to proposal to close the bus split at Arapuni - deferral of permanent closure until 2017. Supporting information [ pdf 122.02 KB ] March 2015
Arapuni Bus Split Closure We are proposing to close the bus split at Arapuni as there is a net benefit in doing so. A teleconference will be held to go over the proposal.
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Supporting information [ pdf 123.68 KB ] November 2014
Paraparaumu 220 kV Project We have undertaken a net benefit test for reconfiguring the grid at Paraparaumu such that this facility becomes connected to Transpower's 220 kV lines allowing for the removal of the 23 km of 110 kv transmission line between Paraparaumu and Pauatahanui substations Supporting information [ pdf 215.87 KB ] September 2013
Arapuni Bus Split Opening We have reviewed the Net Benefit Test for continuing the Arapuni grid reconfiguration following a spare transformer for T1 at Arapuni being brought into service.  There is a net benefit in splitting the Arapuni bus.  We will open the Arapuni bus split from 25 June 2013 13:00 until further notice Supporting information [ pdf 17.39 KB ] June 2013
Arapuni Bus Split Closure We have reviewed the Net Benefit Test for continuing the Arapuni grid reconfiguration following the outage of transformer T1 at Arapunui.  There is no net benefit in splitting the Arapuni bus while T1 is out of service.  We will close the Arapuni bus from 28 May 2013 16:30 until further notice Supporting information [ pdf 179.66 KB ] May 2013
Arapuni Bus Split Continuation Transpower has undertaken a net benefit test to assess the continuation of the Arapuni Bus Split until commissioning of the Wairakei–Whakamaru C line and replacement Tarukenga interconnecting transformers.   October 2012
Mangamaire Bus Split Opening Transpower proposes to open the bus split at Mangamaire for 6 weeks from 30 June 2012. Supporting information [ pdf 772.08 KB ] June 2012
Mangamaire Bus Split Opening Transpower proposes to open the bus split at Mangamaire between the dates of 11 May and 30 June 2012. Supporting information [ pdf 356.08 KB ] May 2012
Arapuni Grid Reconfiguration Transpower has implemented a system split at Arapuni between 6:00 and 21:00 on weekdays.  The system split is a permanent change in the way the grid is configured and is effective from 29 September 2011. Supporting information [ pdf 240.56 KB ] September 2011
Studholme-Timaru Split Closure Transpower is closing the operational split between Studholme and Timaru annually between October and April effective from 28 January 2010. This is to reduce loss of supply to NZ Dairies Limited plant at Studholme during an outage of the main circuit supplying from the south. Supporting information [ pdf 94.77 KB ] January 2010

Approach and assumptions for undertaking cost/benefit analysis [ pdf 268.3 KB ]