• Review of events of 13 and 14 December 2011

  Published: 09/12/2013 12:00am

  On 13 December 2011, circuit breakers at the Huntly power station tripped on protection, resulting in the disconnection of generation. Read More

• Review of 26 September 2011 infeasibility situation

  Published: 09/12/2013 12:00am

  Trading period 16 on 26th September 2011 involved a confluence of several pricing and metering issues that together tested the process by which final prices are calculated. Read More

• Review of August 2011 frequency keeping costs

  Published: 09/12/2013 12:00am

  The total frequency keeping costs during August 2011 were the highest since December 2009, when the system operator included a revised frequency keeper selection method in its new market system. Read More

• Review of price separation during HVDC reversal

  Published: 09/12/2013 12:00am

  Following the introduction of the new market system project (MSP) by the system operator in mid 2009, the modelling practice for the HVDC in the final pricing schedule has changed. Read More

• Analysis of historical offer revisions

  Published: 09/12/2013 12:00am

  Under certain specified circumstances the Code allows generators to revise their offers up to two hours before the start of a relevant trading period. Read More

• Review of high spring washer resolution issue with SFT

  Published: 09/12/2013 12:00am

  Prior to the introduction of the simultaneous feasibility test (SFT) in March 2011, security constraints were applied manually, with one constraint being applied to parallel lines. Read More

• Review of Stratford peaker commissioning 8 February 2011

  Published: 09/12/2013 12:00am

  The system operator increased the North Island instantaneous reserve (IR) requirements from 08:30 to 15:00 (trade periods 18 to 31) on 8th February 2011. Read More

• Dispatch of unscheduled generation: 23-27 January 2011

  Published: 09/12/2013 12:00am

  We released a report on events surrounding plant being constrained on in late January 2011, particularly Huntly Unit 5 on 23-27 January 2011. Read More