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New Zealand Inter Island HVDCPole 3 Project

IPENZ Presentation

18 February 2010Wellington

Peter Griffiths – Project Director HVDC

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NZ Inter Island HVDC Link

• NZ HVDC Inter Island link:– only high voltage transmission

link between the South and North Islands

– balances the distribution of energy between islands, helping to carry electricity from where it is generated to where it is needed.

• Haywards & Benmore contain both Pole 1 & 2 of the HVDC link and are critical parts of New Zealand’s national grid

Benmore

Haywards

Benmore

Haywards

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Hybrid HVDC Link - Pole 1 and 2

Pole 1Mercury Arc Valves(1965 – 600MW)(1992 – 540MW)

Pole 2Thyristor Valves(1991 – 700MW)(1997 – 500MW)

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Hybrid HVDC Link - Today

Pole 1Mercury Arc Valves130MW - 200MWNorth Flow Only

Pole 2Thyristor Valves

700MW

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Hybrid HVDC Link - Today

BENMORE220 kV

HAYWARDS220 kV

Cable 6

Cable 4

Pole 2 (existing thyristor

Converters 700 MW)

535 km DC line section – South

Island

35 km DC line section

North Island

40 km Cook Strait Cables

+ 270 kV

- 350 kV

Cable 5

HAYWARDS110 kV

C7BENMORE

16 kV

Ground (Earth/Sea) Return Current mode

F479.3 Mvar

79.3 Mvar

F3

F3

F4

106.3 Mvar

106.3 Mvar

C1

60 Mvar

T1

C4C335 Mvar

each

T5

C2 60 Mvar

T2

40 MvarR5

40 Mvar

R1

F2

50.5 Mvar

50.5 Mvar

F1

F247.5 Mvar

47.5 MvarC8

C9

C10Pole 1 assets

Pole 2 assets

VG3

VG4

P1B

VG2

VG1

P1A

F1

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HVDC Pole 3 Project• Pole 1 now 44 years old - core technology is obsolete• EC approval to replace Pole 1 was received September 2008• The new pole will be called Pole 3 – 700MW nominal rating• The project will be implemented in stages

* Stage 3 – Not part of EC Approval (2017 or beyond)

700

HV

DC

Bip

ole

Cap

acity

(MW

)

2009 2012 2014 2017+

1000

Date

Stage 1

Stage 2

Stage 3

1200 14

00

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Replace Pole 1 with Pole 3

Pole 3Thyristor Valves(2012 – 700MW)

Pole 2Thyristor Valves

(1991)

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HVDC Link – Post Pole 3 Project

BENMORE 220kV

HAYWARDS 220kV

Pole 2 existing

Thyristor converters (700 MW)

535 km DC line section South Island

40 km Cook Strait Cables

+ 350 kV

- 350 kV

HAYWARDS 110kV

C7

F4A & B

F3A & B

79.3 MVAr(11 /13 & 24 HP)

Existing

C7-C1065 Mvar

each

Cable 6

Cable 4

Cable 5

4 0 Mvar

C1

60 Mvar

T1

C4C335 Mvar

each

T5

C2 60 Mvar

T2

R5

4 0 Mvar

R1

35 km DC line section North

Island

Pole 3 Thyristor

converters (700 MW)

106.3 MVAr(12HP & 24HP)

Stage 1Stage 2Stage 3

F7

F816 MVAr (5th/ 7th)

16 MVAr (5th/ 7th)

C8

C9

C10

F5A & B(A : 11 /13 /24) 60 MVAR

(B : 24 HP) 49 MVAR

F5

F7

STATCOM 2

80 MVAr (11 /13/ 24 HP)

60 MVA

60 MVA

STATCOM 1

+/- 60 MVAr continuous (+110 / -109 @ 1pu

short term)

F6

F8

49 MVAr (24 HP) F6B

+/- 60 MVAr (+110 / -109)

Cable 7

4th Cable (not in tenders)

F6A 60 MVAr (11 /13 /24)

80 MVAr (11 /13/ 24 HP)

80 MVAr (ST 3)

80 MVAr (ST 3)

79.3 MVAr(11 /13 & 24 HP)

106.3 MVAr(12HP & 24HP)

F3A & B

F4A & B

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HVDC Pole 3 Project - Scope

Awarded to Siemens – 30 Oct 2009

Awarded to Brian Perry13 Nov 2009

Awarded to PauwelsJan 2010

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Siemens Solution

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Key Issues• Safety• Operation of Pole 2 not to be detrimentally impacted

during the construction and commissioning of Pole 3– Physically separate control building for Pole 3– Site management– Pole 2 outages to be well signalled in advance, and undertaken

at times which minimise impact on security and the market– Pole 1 to remain available for operation during Pole 3

construction• Minimise duration between Pole 1 decommissioning and

completion of Pole 3 trial operation

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Key Issues• Pole 3 proven to meet or exceed target availability levels

prior to replacing Pole 2 control & protection systems• Pole 3 not to be detrimentally impacted during

replacement of the Pole 2 control & protection systems• Seismic design• Ratings, functionality and performance• Project timeline

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Pole 3 Project TimelineActivity Start Finish

Design & Manufacture (inc FAT) Nov 2009 May 2011

Pole 3 Site Works (Construction and installation) Jan 2010 Nov 2011Pole 1 Decommissioning Sep 2011

Pole 3 Pre-commissioning Nov 2011 Dec 2011

Pole 3 Commissioning & System Tests Jan 2012 Feb 2012

Pole 3 Trial Operation(Stage 1A Completion)

Mar 2012 Apr 2012

Pole 2 Control System Upgrade Sep 2012 Feb 2013

Bipole Control System Upgrade(Stage 1B Completion)

Sep 2012 Feb 2013

Haywards Statcom Commissioning(Stage 2 Completion)

Sep 2013 Dec 2013

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2

Benmore - Existing Site &Locations for New Equipment

1

A

B

PS

3

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Benmore• Preparation of Site

- Site Improvement Works- Removal of Pole 1

• Stage 1 (1000 MW)- AC Switchyards – extension

of 220 kV busbars- Valve Hall and Thyristor

Valves- Converter Transformers- DC Switchyards- AC Harmonic Filters - 220 kV- Control building and controls

- new Pole 3- upgrade Pole 2- new Bipole & Station

Future (not yet approved):• Stage 3 (1400 MW)

- AC Harmonic Filters - 220 kV

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Benmore

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Haywards – Existing Site &Locations for New Equipment

1

2A

B

SC

C

3

D

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Haywards• Preparation of Site

- Site Improvement Works- Switchyard C- Removal of Pole 1 (Swyd D)

• Stage 1 (1000 MW)- AC Switchyards - Valve Hall and Thyristor Valves- Converter Transformers- DC Switchyards- AC Harmonic Filters- Control building and controls- Station Services- 2 x Synchronous Condenser Unit

Transformers

• Stage 2 (1200 MW)- Statcom- 2 x Synchronous Condenser Unit

Transformers

• Stage 3 (1400 MW) (not yet approved)- AC Switchyards - AC Harmonic Filters- Stacom

2

A

B

SC

C

3

D

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Haywards

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Haywards Valve Halls & Control Buildings

Pole 3 Valve hall

Pole 3 control room

Pole 2 control room

Pole 2 Valve hall

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Pole 2 Pole 3

Nominal rating 560 MW 700 MW

Continuous overload rating 700 MW 735*/770** MW

Short term overload rating*=with and **=without redundant cooling

840 MW for 5s 1000 MW for 30min

Synchronous Condenser @ HAY 240 Mvar

STATCOM @ HAY - 2 x 60 Mvar

Filter nominal ratings at HAY (existing and future) @ 220 kV

2 x 106 Mvar 2 x 109 Mvar

Filter nominal rating at BEN (existing and future) @ 220 kV

2 x 80 Mvar 3 x 80 Mvar plus one spare

Main System Parameters

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Thyristor ValvesPole 2 Pole 3

Thyristor type 4” diameterelectrically triggered

5” diameter light triggered

Valve max cont current rating 2,000 A 2,860 A

Thyristor peak reverse voltage 5.5 kV >7.5 kV

Thyristors per valve 66 52

Thyristors per quadrivalve unit 264 208

Thyristors per end of the link 792 624

Quadrivalve mass 20 t 17 t

Valve Hall foot print 29 x 19 m 42 x 16 m

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Converter TransformersPole 2 Pole 3

Number of Converter Transformers 8(3 + 1 spare / end)

8(3 + 1 spare / end)

Nominal rating 217 MVA / phase 271 MVA / phase

Converter transformer mass(with /without oil)

324 t / 216 t 330 t / 232 t

Oil volume / converter transformer 85,000 litres 91,000 litres

Conv. Trans. enclosure footprint 26 x 15 m 38 x 11 m

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Control Hierarchy

Station Controls

Bipole Controls

Pole Controls

•Reactive Power Control•Modulation Controls

•Runbacks•Frequency Stabilisation•Spinning Reserve Sharing

•Power Order Calculator•Round Power•Current Balance Controller•Bipole Power Capacity Calculator

•Current Order Calculation•Power Order Calculator (for pole level modulations)•Pole-to-pole power Transfer•Current Order Setting•Pole level sequences•Tap changer control•DC filter and switchgear control

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Site Establishment at Haywards

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Switchyard B (Pole 3 Area)

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Switchyard B (New Filters)

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Pole 1 / Switchyard D

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Dog Box

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Removing Kaitawa Street Houses

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Planning for Commissioning

• Commissioning of Pole 3, the subsequent Pole 2 control system upgrade and bipole commissioning will require a high degree of communication, support and coordination amongst industry participants

• A Pole 3 Commissioning Industry Advisory Group will be established later this month

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Questions ?