Waikato and Upper North Island (WUNI) Voltage Management Investigation

Waikato and Upper North Island (WUNI) Voltage Management Investigation Transpower, Development Group Anna Li 1

Presentation Outline Needs Investigation (phase 1) UNI thermal decommissionings, identified voltage stability limits Options Investigation (phase 2) Long-list consultation paper, short-list components, development plans and economic analysis Preferred Options (phase 3) Short-list consultation of preferred option, Major Capital Expenditure Project (MCP) submission to Commerce Commission

Upper North Island thermal decommissioning

Transpower s Investment Approval Process

Phase 1 - Needs Investigation Completion date Q2 2016

System support required beyond Year 2022

Phase 2 - Options Investigation Scheduled completion date Q1 2017

Long-list consultation paper Covered: Need and project scope Long-list of components Information on non-transmission solutions Grid Support Contract product design Criteria for short-listing Demand growth assumptions Removal of DGPP and RCPD charges Motor load information Existing generation in the UNI Dynamic reactive support Generation scenarios Demand growth assumptions Analysis period Value of unserved energy Discount rate assumptions DGPP - distributed generation pricing principles RCPD - regional coincident peak demand

Long-list consultation feedback Key points: Agreement to the need Lots of uncertainty hence need for flexibility Don t assume any new thermal plant in UNI Allow for possibility of early Tiwai exit Synchronous condenser conversions RCPD and ACOT proposals will raise UNI peak Support for batteries What about thermal transfer issues? Comments about the TPM! ACOT - Avoided Cost of Transmission

System condition post 2022 Static limit (PV) at 95% (MW) Dynamic limit at 95% (MW) Binding limit Forecast year Base case 2702 >2702 static 2014 V (pu) 1.1 1.06 1.04 HAY TNG BPE TKU WRK V-P curve for North Island buses North Island voltage profile at nose point and at 95% from PV nose point base case base case 1.05 1.02 SFD WKM HEN ALB BPE OTA 1 0.98 OHW 1 HLY HAM 0.96 HLY 0.94 0.95 MDN220A1 ALB220A1 BRB220 SWN220 GLN220 MDN HEN220A1a PAK220A OTA220B1 HLY220A OHW220A HAM220A WKM220A1 0.92 TWH220 TMN TWH TMN220 0.9 TKU-220-1 0.9 TNG220 0.88 SFD220A1 0 1 at PV Nose 2 via CNI 3 4at PV Nose 5 via Taranaki 6 7 at 95% 8PV nose via 9 CNI 10 at 11 95% PV nose 12via Taranaki 13 BPE220A1a 14 HAY220A 0.85 2640 2660 2680 2700 2720 2740 2760 2780 2800 2820 2840 2860

Short-list of components categories Include: Generation - Huntly Rankine units Synchronous condenser Static synchronous compensator (STATCOM) Static Var compensator (SVC) Shunt Capacitors Series capacitor 220 kv and 400 kv conversion with and without 3 rd cable from Brownhill-Otahuhu

Development Plans and Economic Analysis Building Block PV nose PV (95%) Dynamic (95% PV) Forecast year Base Case xxxx xxxx pass/fail 20xx $$ Component 1 xxxx xxxx pass/fail 20xx $$ Component 2 xxxx xxxx pass/fail 20xx $$ Component 3 xxxx xxxx pass/fail 20xx $$ Component 4 xxxx xxxx pass/fail 20xx $$ Component 5 xxxx xxxx pass/fail 20xx $$ Cost Year 1 Year 2 Year 3 Year 4 2045 Development Plan 1 PV PV Dyn PV PV Dyn PV PV Dyn PV PV Dyn PV PV Dyn Total nose (95%) (95% PV) nose (95%) (95% PV) nose (95%) (95% PV) nose (95%) (95% PV) nose (95%) (95% PV) Cost Componet 1 xxxx xxxx pass Componet 2 xxxx xxxx pass Componet 3 xxxx xxxx pass Componet 4 xxxx xxxx pass $$$

Phase 3 - Preferred Options Scheduled completion date Q4 2018

Key Milestones Phase 3 Short-list consultation of preferred option Major Capital Expenditure submission to Commerce Commission Commission's approval and transition to Grid Projects

Presentation Summary Needs Investigation (phase 1 completed Q3 2016) Options Investigation (phase 2 underway Q2 2017) Preferred Options (phase 3 Q4 2018)

WUNI Voltage Management Project Site

Outage Visualisation Transpower, System Operator Service Industry Workshop 2016 Angela Houston Richard Rowell

Current outage information POCP IONS

Other information available

Outage Visualisation Tool Outage visualisation prototype created by EMS Outages can be seen on geographic maps of New Zealand using our geospatial capability More visibility of what outages are happening where and when Easier to see concurrent outages and highlight possible conflicts Assist in covering for future risks

Planning Benefits Benefits to outage management across a wide audience Many different needs and uses of outage information Make it easier and more efficient to assess and manage outages

Daily Outages

Outage Detail

Outage Selection

Transformer Outage Detail

Outages on same line

Generation outages

Generation outage detail

Rain risk

Substation equipment

Schematic view

NIPS/SIPS Schematic

National Winter Group Transpower, System Operator Service Industry Workshop 2016 Erich Livengood

National Winter Group Winter 2006 Industry working group Initiated improvements

Analysis Annual report Pre-winter Supply margin Worst case Reality is offer driven

The Twin Peaks Demand Gap analysis Generation

The Future Supply margin analysis is required Does it have to be National Winter Group?

New Zealand Generation Balance

NWG vs NZGB

Where to from here? Communication with National Winter Group members Comparison of NWG and NZGB analysis 1 March 2017

Load Forecast Accuracy Transpower, System Operator Service Industry Workshop 2016 Erich Livengood Richard Rowell

Agenda Load forecast and its use Load forecast and other schedule inputs System Operator load forecast accuracy Developments: EMS load forecast Options for an improved forecast?

Load forecasting and use Medium term load forecast (MTLF) Spans 15 days, including today regional Components Long term seasonal component from last 4 wks Short term local component from last 2 days Weather based on forecast weather Refined adjusts based on prior performance Energy Market Services load forecast *Load forecast methodology link

Schedule accuracy is more than load forecast Market schedules match forecast load, bids and offers Variables which may cause the forecast price to vary from actual include (but are not limited to): Intermittent and distributed generation Load management (by networks and autonomous) Accuracy of load forecast Bid and offer and compliance Price is the intersection of demand and supply

Load management and intermittent generation equate to hundreds of MW of difference ~200 MW 37 MW Wind Forecast accuracy 2.5 hours ahead 2-5 August 2016 Load Management, sample day July 16 Orion Network For August 2016, average wind forecast error was 45MW vs. LF error of 101 MW. 27% of the time, wind error was greater than LF error.

Accuracy of SO medium term load forecast Sample accuracy for August 2016 2.5 hours ahead of the trading period vs actual Bias average error ~50 MW MAPE 2.0% (2.2% conforming nodes) Bias higher for high loads

Forecasting does improve closer to gate closure Demand forecast 6.5 hours ahead August 16 Demand forecast 2.5 hours ahead August 16 Transpower is now noting accuracy monthly what information is useful?

Transpower will commence publishing forecast accuracy periodically MAPE for month Conforming and total demand What would you find useful in forecast reporting?

Load forecasting trial 2012

Developments in forecasting: EMS load forecast

Variables used in forecasting Actual load Historical load Temperature Humidity Cloud cover Wind speed Wind direction Rain Radiation

Measuring accuracy Error calculations are based on differences between forecast at 2.5 hours prior to dispatch and observed SCADA load. MAPE (mean absolute percentage error) is defined as arithmetic average of absolute differences between actual and observed value divided by actual value

Comparison June July August Transpower 1.5% 1.6% 2.0% EMS / TESLA 0.8% 1.2% 1.2% (MAPE %)

MAPE(%) June-August

Peak load performance 8 August 8000 TESLA Forecast vs Actual 8 August 2016 7000 6000 5000 4000 3000 2000 1000 0 Tesla: MAPE: 1.3% Forecast Actual

MAPE Comparison 8 Aug 2016

MAPE Comparison 26 July 2016

MAPE Comparison 2 June 2016

What are my options for an improved forecast? EMS forecast available for subscription An industry enhancement project Tesla based forecast, benefits from forecaster inputs (probably) Includes adjustments for demand management Significant capital and ongoing operational costs Forecast improvements flow thought to schedules If approved, earliest project start Spring 2018

Emerging Technology Transpower s Programme of Work Transpower, System Operator Service Industry Workshop 2016 Andrew Gard

Outline Emerging Technology Programme Solar PV Investigation Project Battery storage study and trial

Emerging Technology Programme Background Objectives Components

Solar PV Investigation Project Objectives: Understand the technology and its impacts on the power system. Ensure we have ability to plan and operate future power system to meet our PPOs.

Solar PV Investigation - Scope Phase 1 Impacts System Operations Ramping capability Frequency Management Volt. Management System Stability Transient stability Voltage stability Phase 2 Solutions Market Real Time Operation Policy and standards

Solar PV Investigation - Status Ramping capability Ramp rate limits no issue with 4GW solar PV Remaining Phase 1 scope underway, due for completion by mid 2017 Phase 2 - only if issues are identified in Phase 1

Battery Storage System Study & Trial Investigate potential benefits at transmission level: Frequency Control - Synthetic inertia - Governor response - Frequency keeping Voltage Control - Improve voltage control - Provide additional dynamic reactive power reserve - Improve voltage stability limit System Security - Improve operation limits by locating near to load centres

Battery Storage System - Study & Trial Trial objectives & learnings: Battery technologies Design criteria and mode of operation Electrical behaviour and performance Commissioning and testing requirements Regulatory, market and technical challenges System operation requirements Economic benefit opportunities

Where to from here? Transpower emerging technology programme Solar PV Investigation Project Balance of Phase 1 underway Preparation for Phase 2 as required Battery Storage System studies & trial Challenges to come What about EV? Other?

Questions?

Extended Contingent Event Bus Bar Policy Project Transpower, System Operator Service Industry Workshop 2016 Justin Blass

Our role Role of system operator Analyse, evaluate, and recommend the appropriate risk management of power system events Credible event review process

What classification options exist? CE ECE OTHER CONTINGENT EVENT EXTENDED CONTINGENT EVENT OTHER EVENT Pre-event mitigation - Load management - Generation constraints Prevent consequences Post-event mitigation - SPS - AUFLS/AUVLS Reduce consequences Rely on available mitigations - Reserves - AUFLS - Restoration plans Accept consequences

Why review? Credible event reviews 2009 and 2014 classified loss of a bus bar as ECE In 2015 Manapouri bus bar treated as CE during double circuit outage What mitigation should New Zealand have for bus bar trippings? C R E

Scope of project Establish interim policy Bus bar classified as other events for voltage Review and improve classification methodology Trial new classification methodology Document and present findings Complete bus bar classification assessment

What s next? Oct/Nov 2016 Present proposed methodology and trial results June 2017 Complete bus bar classification assessment 2017/2018 Complete interconnecting transformer classification assessment

Hawkes Bay Snow Storm 6 August 2016 Transpower, System Operator Service Industry Workshop 2016 Matt Hansen

Introduction Summary of the Hawkes Bay event Potential islanding process

Heavy Snow Heavy snow hit the central North Island in the early hours of Saturday morning. The Hawkes Bay is supplied via a single line between Taupo and Napier RDF_WRK_1 and WHI_WRK_1 circuits. Permanent operational split between Woodville and Fernhill

Core Grid 70MW WRK 70MW Pre-event G WHI RDF 220kV WTU FHL RDF 220kV X WPW TUI 70MW G

Core Grid WRK G 140MW WHI 0MW X 02:30 RDF 220kV WTU FHL RDF 110kV X WPW TUI 70MW G

Core Grid WRK G 0MW WHI X 0MW X 02:45 RDF 220kV WTU FHL RDF 110kV X WPW TUI 70MW G

Core Grid WRK G 0MW WHI X 0MW X 02:45 RDF 220kV WTU FHL RDF 110kV X WPW TUI 0MW X

Core Grid WRK G 170MW WHI 0MW X 05:30 RDF 220kV WTU FHL RDF 110kV X WPW TUI 40MW G

Core Grid WRK 85MW G 0MW WHI 0MW X 09:30 RDF 220kV WTU FHL RDF 110kV X WPW TUI 120MW G

Core Grid WRK 85MW G 0MW WHI X 0MW X If Successful RDF 220kV WTU FHL RDF 110kV X WPW TUI 120MW G

Core Grid WRK 125MW G 38MW WHI 0MW X 09:59 RDF 220kV WTU FHL RDF 110kV X WPW TUI 120MW G

Core Grid WRK X 0MW WHI X 0MW X 10:01 RDF 220kV WTU FHL RDF 110kV X WPW TUI 0MW X

New Process for Areas on N If all of the following are true: Area >100MW of load on N security Increased risk of trip on remain asset enough local generation to meet local load The generation is capable of islanding Then: We will constrain local generation to match local load to increase chance of successfully islanding

New Process Continued Connected parties can opt-out through agreement by all distributors and direct connects Area <100MW of load on N can opt-in by agreement Area large enough to cause cascade failure will be managed regardless of level of risk (no optout)