Lessons learnt in South Island power system event

09 July 2018

Today, Transpower released a report documenting the 2 March 2017 South Island automatic under-frequency load shedding (AUFLS) event. This was a complex power system event where the South Island power system split into two separate systems.  While the consumer impact of the event was relatively well contained, immediately after the event there was considerable pressure to stabilise the grid and avoid further loss of supply in the South Island.

Transpower Acting Chief Executive John Clarke says, “We have learnt significant lessons as a result of this event.  We have taken time to do a comprehensive investigation, including further subsequent reviews into how the event occurred in the first instance, and the actions that we took immediately afterwards as we stabilised the system.  The report documents where we went wrong, including how operators responded both within Transpower’s control room and our interactions with other control rooms”.

A number of significant improvements have been identified to ensure that if such an event were to occur again, a better outcome would result.  “Improved assessment of situations that could lead to a similar event is our absolute focus.  This includes better training, improved procedures and communication between control room staff and with the industry,” says Clarke.  

“The report also documents other key actions that have been consolidated into 13 actions. Progress on these actions, five of which have been completed already, will be reported on regularly on our website, to provide transparent information on our progress.

“Transpower acknowledges the valuable contribution and advice we received from the Electricity Authority, as well as others in the industry.  Discussions such as these are critical to ensure that we continue to meet the expectations of our customers.”  


For further information, please contact:   

Kerri Osborne, Corporate Communications Manager, 021 195 8613.