Reports on this page
| 2020 | 2018 | 2017 | 2016 | 2015 | 2014 | 2013 | 2012 |
Reports from 2020
 Assurance Process Review Report [ pdf 2.32 MB ] |
Aug 2020 |
The following report provides detailed information gathered during Transpower’s review of the Assurance process. The review has been undertaken to identify process gaps and necessary enhancements to mitigate the risk of incidents and improve the service overall. The report includes recommendations to improve the Assurance process which include; standardising the Assurance Form, improving the planning process overall and streamlining Transpower’s internal processes by removing the current relaying service to enable parties to transfer assurances directly. A timeframe to implement these changes will be developed through additional industry engagement. The recommendations have been submitted as part of Transpower’s feedback on the Electrical Engineers Association (EEA) Assurance Guideline consultation and will be presented at a series of industry forums for Service Providers, Generators and Distribution Companies in September. For further information contact: michelle.ward@transpower.co.nz |
| 2019 HVDC P2 Oscillations Investigation [ pdf 1.05 MB ] |
May 2020 |
On 31 May 2019 oscillations were identified on the New Zealand power system. This report outlines the system operators investigation into the cause of these oscillations, mitigations implemented through to the eventual resolution by the grid owner. If you have any feedback on this document please email us at system.operator@transpower.co.nz |
Reports from 2018
| Transpower Action Report - 2 March 2017 South Island AUFLS Event [ pdf 472.11 KB ] |
Dec 2018 | An updated version of the South Island AUFLS Event Action Report detailing progress on actions. |
| Transpower Action Report - 2 March 2017 South Island AUFLS Event [ pdf 468.73 KB ] |
Oct 2018 | This report captures the complete list of actions being undertaken by Transpower following the 2 March 2017 South Island AUFLS Event Report and their progress towards completion. |
| Report on 2 March 2017 South Island AUFLS Event | Jul 2018 |
On 2 March 2017, New Zealand experienced a major and complex power system event. The event resulted in the South Island power system splitting into two separate systems. Approximately 120 MW (16%) of electricity used by consumers in the upper part of the South Island was disconnected for up to 90 minutes. |
Reports from 2017
| Maraetai Bus Bar - Risk of Trip [ pdf 574.55 KB ] |
Aug 2017 |
Update to the MTI Bus Risk report outlining the treatment of the MTI Bus as a CE risk from September to February annually. |
| High RTP Price 21 May 2017 [ pdf 472.81 KB ] |
Jun 2017 | A detailed explanation/commentary on the high real-time price that was observed on 21 May 2017 at 19:00 at the North Island reference node. |
| POCP Report for NZGB Commencing 8 Mar 2017 [ pdf 70.12 KB ] |
Mar 2017 | The NZGB study, which was undertaken as at the 8th of March 2017, indicated potential generation balance risks that could arise from higher demand (higher-than-forecast-load), further generation outages or insufficient offers for the duration of major North Island outages in November 2017 |
| Preliminary Report South Island AUFLS Event [ pdf 1.3 MB ] |
Mar 2017 | This report is an early summary of events which occurred on 2 March which resulted in an under frequency event in the North and South Islands and a separation and re-synchronisation of the South Island power system. |
Reports from 2016
| Price Separation Report 6 Dec 2016 [ pdf 491.13 KB ] |
Dec 2016 | Modest price separation between the North and South Island occurred on the morning of Tuesday 6 December 2016, this report details our findings. |
| Summary for the SA black System Event 11 Nov 2016 [ pdf 517.37 KB ] |
Nov 2016 | Following the South Australian “System Black” event of 28 September 2016, Transpower has undertaken an initial review of the known events, as described in two reports issued by the Australian Energy Market Operator. |
| Analysis of the North Island Price Spike on 02 June 2016 [ pdf 185.63 KB ] |
Oct 2016 | This report outlines the events and the resulting extreme wholesale electricity prices on the evening of 2 Jun 2016. It also explores the forecast, market participant and System Operator (SO) responses. |
| POCP Report for NZGB Commencing 20161003 [ pdf 18.01 KB ] |
Oct 2016 | The NZGB study commencing on the 3rd October 2016 indicates potential risks that could arise from higher demand (higher-than-forecast-load), further generation outages or insufficient offers for the duration of major North Island outages in November 2016. |
| Changes to the Reserve Management Tool [ pdf 274.81 KB ] |
Sep 2016 | A technical description of the changes to the Reserve Management Tool to use the MWmax for Intermittent Generation and to model the HVDC 5 second overload. |
| High Reserve Requirements 10-11 September 2016 [ pdf 91.53 KB ] |
Sep 2016 | This report explains the investigation into Instantaneous Reserve requirements on the 10 and 11 September 2016. |
| POCP Report for NZGB Commencing 20160815 [ pdf 95.24 KB ] |
Aug 2016 | The NZGB study commencing on the 15th of August 2016 indicates potential risks that could arise from higher demand (higher-than-forecast-load), further generation outages or insufficient offers for the duration of major North Island outages in November 2016. Minutes of Nov 2016 Outage Coordination Meeting [ pdf 362.27 KB ] held on 26 July 2016. |
| Market Report UNI Voltage Stability Constraint Temporarily Tightened on 1 Aug 2016 [ pdf 470.6 KB ] |
Aug 2016 | This report explains the actions of the Transpower as System Operator to temporarily tighten the constraint on 1 Aug 2016. |
| High NI Energy and FIR Prices 26 July 2016 [ pdf 384.98 KB ] |
Aug 2016 | This report explains the calculation of final energy and FIR prices for trading periods 16, 17, and 18 on 26 July. |
| HAM-WKM 1 Outage Assessment for outage 8 Jun 16 to 11 Jun 16 [ pdf 102.21 KB ] |
May 2016 | Outage assessment for HAM-WKM 1 outage from 8 - 11 Jun 16. |
| South Island Reserves Oscillation April 2016 [ pdf 274.92 KB ] |
April 2016 | This report details an issue influencing South Island Instantaneous Reserve (IR) quantities between 8 April and 11 April 2016. Significant oscillations in South Island IR quantities between trading periods were occasionally observed. |
| Convergence of South Island reserve requirements [ pdf 464.14 KB ] |
April 2016 | This report discusses the changes to reserve requirements between subsequent solves in the forward looking schedules, and high reserves observed in the South Island, during the OHA_TWZ_1 outage. |
| MAN-NMA 1 and 2 Outage Assessment for outage 22 April 2016 [ pdf 153.43 KB ] |
April 2016 | Outage assessment for MAN_NMA_1 and MAN_NMA_2, this outage removes two of the four circuits into MAN. N-1 security will be maintained on the remaining 2 circuits – INV_MAN and MAN_NMA_3. |
| HAY Filter 3 NZGB Assessment for outage 7 June 2016 [ 202.5 KB ] |
Apr 2016 | The NZGB study commencing on the 16th of March indicates a potential shortfall during the scheduled HAY Filter 3 outage (7th - 13th June 2016). The maximum shortfall is 30 MW during weekday peaks after a N-1-G contingency. |
| Price separation Haywards HVDC filter outages [ pdf 436.51 KB ] |
Mar 2016 | This report discusses the price separation that was observed during the Haywards HVDC filters outage between Monday 7th March 2016 and Thursday 10th March 2016. |
| TKU Black Start Market Report Mar 2016 [ pdf 342.99 KB ] |
Mar 2016 | This report is a summary of the market events surrounding the Tokaanu black start test on 21 February 2016. |
| HVDC Bipole Trip 11 Dec 2015: Technical Commentary [ pdf 541.39 KB ] |
Mar 2016 | This report on the event is a technical commentary on the equipment, the event and the management of impacts from both Transpower’s grid owner and system operator perspectives on the HVDC Bipole trip on 11th December 2015. |
Reports from 2015
| HVDC Bipole Trip 11 Dec 2015 [ pdf 427.68 KB ] |
Dec 2015 | This report documents the technical and market details on the HVDC Bipole trip on 11th December 2015. |
| Manapouri 220 kV Double Circuit Outage 16 May 2015 [ pdf 537.53 KB ] |
Jul 2015 |
This report reviews and documents outage planning activities, the operational activities and market outcomes related to the MAN 220 kV outage. It also identifies potential planning, operational, policy, tool and communication improvements across Transpower. The review documentation is below:
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| High Spring Washer Price Situation 22-24 April 2015 [ pdf 872.47 KB ] |
Jun 2015 | This document provides market participants with our report on the High Spring Washer Situation that occurred on 22-24 April 2015 |
| High Spring Washer Price Situation 12 Mar 2015 [ pdf 457.1 KB ] |
May 2015 | This document provides market participants with our report on the High Spring Washer Situation that occurred on 12th Mar 2015 |
| High Spring Washer Price Situation 9 Jan 2015 [ pdf 504.61 KB ] |
Mar 2015 | This document provides market participants with our report on the High Spring Washer Situation that occurred on 9th Jan 2015 |
Reports from 2014
| Maraetai Bus Trip [ pdf 530.39 KB ] |
Dec 2014 | This document provides market participants with our initial report on the bus trip at Maraetai on 8th December 2014. |
| Credible Event Management [ pdf 1.25 MB ] |
Dec 2014 | During 2014, the System Operator undertook a major review of its policy in relation to the identification, classification and management of credible events. The review documentation is listed below:
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| Loss of 370 MW of Manapouri Generation Report [ pdf 151.98 KB ] |
Nov 2014 | This document provides market participants with our initial report on the three Manapouri generation units that tripped on 27 Nov 2014 and resulted in the loss of approximately 370 MW of power supply in the South Island. |
| Fire at Penrose Substation Report 5 October 2014 [ pdf 153.82 KB ] |
Nov 2014 | This document provides market participants with our initial report on the fire at Penrose Substation on 5th October 2014. |
| Roxburgh Export Overload Protection (REOLP) Security Constraints Analysis [ pdf 484.78 KB ] |
Oct 2014 | This document provides market participants with an indication of what the limiting security constraints will be for high-north transfer out of the Southland region after Stage 1 of the Roxburgh Export Overload Protection (REOLP) Scheme has been made operational. |
| Haywards 220kV Bus Disconnector Fault Report 24 Jul 2014 [ pdf 192.67 KB ] |
Sept 2014 | This document provides market participants with our report on the fault that occurred on a 220 kV bus disconnector at Haywards on 24th July 2014. |
| Reserve Deficit Report 19 Aug 2014 [ pdf 265.29 KB ] |
Sept 2014 | This document provides market participants with our report on the reserves deficit that occurred on 19th August 2014 at 18:00. This reserve deficit caused final prices to approach $10,000/MWh. |
Reports from 2013
| AUFLS Activation 12 Nov 2013 SO Report [ pdf 1.04 MB ] AUFLS Activation 12 Nov 2013 Grid Owner Report [ pdf 498.31 KB ] |
Dec 2013 | Transpower's report to the industry on the 12th November auto under frequency load shedding activation. These two reports should be read together. |
| WRK Ring Security Constraints Analysis (THI SPS Stage 1) [ pdf 430.65 KB ] |
Oct 2013 | This document provides market participants with an indication of what the limiting security constraints will be for transfers through the WRK ring with Te Mihi stage 1 enabled and prior to the commissioning of Te Mihi generation and the THI Intertrip stage 2 being enabled. |
| WRK Ring Constraints Analysis (THI SPS Stage 2) [ pdf 370.42 KB ] |
Jan 2013 | This document provides market participants with an indication of what the limiting constraints will be for transfers through the WRK ring with the THI Intertrip Scheme enabled. |
Reports from 2012
| WRK Ring Constraints Analysis (Pre SPS) [ pdf 399.75 KB ] |
Sept 2012 | This document provides market participants with an indication of what the limiting constraints will be for transfers through the WRK ring prior to the commissioning of the THI Intertrip Scheme. |
| NIGUP Security Constraints Analysis [ pdf 558.6 KB ] |
Jul 2012 | This document provides market participants with an indication of what the limiting security constraints will be for transfers into and out of the Upper North Island region after the commissioning of the NIGUP project. |
| AUFLS Event 13 Dec 2011 Report [ pdf 702.94 KB ] |
Apr 2012 | Report on the 13 December 2011 Auto Under Frequency Load Shedding Event (AUFLS). |
