Waikato and Upper North

Island (WUNI) Voltage

Management Investigation

1

Transpower, Development Group

Anna Li

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

0.85

0.9

0.95

1

1.05

1.1

2640 2660 2680 2700 2720 2740 2760 2780 2800 2820 2840 2860

V-P curve for North Island buses base case

MDN220A1

ALB220A1

BRB220

SWN220

GLN220

HEN220A1a

PAK220A

OTA220B1

HLY220A

OHW220A

HAM220A

WKM220A1

TWH220

TMN220

TKU-220-1

TNG220

SFD220A1

BPE220A1a

HAY220A

BPESFD

TMN TWH

HLY

HAY BPE

TNGTKU WRK

WKM

HAM

OHW HLY

OTAHEN ALB

MDN

0.88

0.9

0.92

0.94

0.96

0.98

1

1.02

1.04

1.06

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

V (pu) North Island voltage profile at nose point and at 95% from PV nose pointbase case

at PV Nose via CNI at PV Nose via Taranaki at 95% PV nose via CNI at 95% PV nose via Taranaki

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 3rd cable from Brownhill-Otahuhu

Development Plans and Economic Analysis

Building BlockPV

nose

PV

(95%)

Dynamic

(95% PV)

Forecast

yearCost

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 $$

Development Plan 1Year 1 Year 2 Year 3 Year 4 … 2045

Total

Cost

PV

nose

PV

(95%)

Dyn

(95% PV)

PV

nose

PV

(95%)

Dyn

(95% PV)

PV

nose

PV

(95%)

Dyn

(95% PV)

PV

nose

PV

(95%)

Dyn

(95% PV)

PV

nose

PV

(95%)

Dyn

(95% PV)

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

• Short-list consultation of preferred option

• Major Capital Expenditure submission to Commerce Commission

• Commission's approval and transition to Grid Projects

Key Milestones – Phase 3

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 VisualisationTranspower, 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

Daily Outages

Outage Detail

Outage Selection

Outage Selection

Transformer Outage Detail

Outages on same line

Outages on same line

Outages on same line

Outages on same line

Generation outages

Generation outage detail

Rain risk

Rain risk

Substation equipment

Substation equipment

Schematic view

Schematic view

NIPS/SIPS Schematic

National Winter GroupTranspower, 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

GenerationDemand

Gap

analysis

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 AccuracyTranspower, 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

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.

37 MW~200 MW

Wind Forecast accuracy 2.5 hours ahead

2-5 August 2016 Load Management, sample day July 16

Orion Network

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

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

(MAPE %)

June July August

Transpower 1.5% 1.6% 2.0%

EMS / TESLA 0.8% 1.2% 1.2%

MAPE(%) – June-August

Peak load performance – 8 August

TESLA Forecast vs Actual 8 August 2016

0

1000

2000

3000

4000

5000

6000

7000

8000

Forecast Actual

Tesla: MAPE: 1.3%

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

69

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 ProjectTranspower, 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

• Pre-event mitigation- Load management

- Generation constraints

• Prevent consequences

CONTINGENT

EVENT

ECE

• Post-event mitigation- SPS

- AUFLS/AUVLS

• Reduce consequences

EXTENDED

CONTINGENT

EVENT

OTHER

• Rely on available mitigations

- Reserves

- AUFLS

- Restoration plans

• Accept consequences

OTHER

EVENT

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?

R

C

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?

Present

proposed

methodology

and trial results

Complete bus

bar classification

assessment

Complete

interconnecting

transformer

classification

assessment

Oct/Nov 2016

June 2017

2017/2018

Hawkes Bay Snow Storm

6 August 2016Transpower, 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 WRK

WTURDF 220kV

FHL

WPW

X

RDF 220kV

WHIG

TUI G

70MW 70MW

70MW

Pre-event

Core Grid WRK

WTURDF 220kV

FHL

WPW

X

RDF 110kV

WHIG

TUI G

140MW 0MW

70MW

X02:30

Core Grid WRK

WTURDF 220kV

FHL

WPW

X

RDF 110kV

WHIG

TUI G

0MW 0MW

70MW

X02:45X

Core Grid WRK

WTURDF 220kV

FHL

WPW

X

RDF 110kV

WHIG

TUI X

0MW 0MW

0MW

X02:45X

Core Grid WRK

WTURDF 220kV

FHL

WPW

X

RDF 110kV

WHIG

TUI G

170MW 0MW

40MW

X05:30

Core Grid WRK

WTURDF 220kV

FHL

WPW

X

RDF 110kV

WHIG

TUI G

0MW 0MW

120MW

X09:30

85MW

Core Grid WRK

WTURDF 220kV

FHL

WPW

X

RDF 110kV

WHIG

TUI G

0MW 0MW

120MW

XIf Successful

85MW

X

Core Grid WRK

WTURDF 220kV

FHL

WPW

X

RDF 110kV

WHIG

TUI G

38MW 0MW

120MW

X09:59

125MW

Core Grid WRK

WTURDF 220kV

FHL

WPW

X

RDF 110kV

WHIX

TUI X

0MW 0MW

0MW

X10:01X

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 opt-

out)