Project Refurbishments in Australasia · Project Refurbishments in Australasia ... Seismic Design Aspect ... • Arrester arrangement including all existing arresters

Project Refurbishments in Australasia Orestes Macchione (HVDC Business Development) IEEE PES General Meeting 2015 Denver (CO), USA

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Topics to be covered

• New Zealand Inter-Island Pole III HVDC Link

• Queensland, Australia Powerlink SVCs 1. Nebo SVC 2. Railway SVCs

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NZ Inter-Island HVDC - Overview • Customer: Transpower NZ • Transmission asset owner and

system operator in New Zealand • Bipole with land- and shore

electrodes • 40 km submarine cable • 570 km overhead line • 220 kV AC / 110 kV AC

• Pole 1 - Mercury Arc Valves • Pole 2 - Thyristor Valves • Pole 3 – LT Thyristors

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Historical Perspective*

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Pole 1 – Mercury Arc Valves (1965)

Pole 2 – Thyristors (1992)

* New Zealand Inter Island HVDC Pole 3 Project CIGRE SCB4 Colloquium 2011, Brisbane, Australia 19-21 October 2011. Peter Griffiths, Transpower

Pole 3 – Light Triggered Thyristors (2014)

HVDC link – Initial Pole1 & Pole2 5

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

HVDC Pole 3 Project - Design 6

Stage 1 - 1,000MW

Stage 2 - 1,200MW

Stage 3 - 1,400MW

Seismic Design Aspect

• Both Converter Stations must have High Level of Seismic Resilience, particularly Haywards which is located only a few hundred meters from an active geological fault line

• Structural diversity between the new Pole 3 and the existing Pole 2 in an attempt to avoid common mode failures

• Seismic isolation of the converter building housing the thyristor valves, converter transformers, and control / auxiliary system

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Converter Building Seismic Isolation

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Converter building is seismically isolated using Lead Rubber Bearings with a free oscillation amplitude of ±600mm, effectively decoupling the building from horizontal ground earthquake motion.

Reactor & Bushing 9

• Reactor isolation • Shake table test

Design Coordination between Existing and New Plant

• Arrester arrangement including all existing arresters – V-I characteristics – Protective levels of the new surge arresters

• Existing Pole 1 DC filters, built identical to Pole 2 DC filters

• Various components installed at the DC neutral bus need to be replaced by components with higher rating

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Reactive Power Control 11

AC Filters

• Overall filter design will ensure that the new AC filters do not cause undue loading of the existing filters during operation

• Wider AC frequency range (+/-2 Hz) for Pole 3 comparing to +/-0.75 Hz for Pole 2

• Triple-tuned AC filters TT11/13/24 • 3rd harmonic filters (ST LO3) will be installed at

Benmore taking potential resonances of pre-existing low order harmonics into account

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Stability, Modulation, and Frequency Control*

• Supplementary Modulation Controls and Runbacks implemented in the HVDC Control System – Weak AC grid – Increased power transfer capability

• DC current modulation to damp voltage swing • Frequency controls such as Constant Frequency

Control; Frequency Keeping Controller and Wellington Over-Frequency Brake

• Round power mode

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*1400 MW New Zealand HVDC Upgrade: “Introducing Power Modulation Controls and Round Power Mode” Simon P. Teeuwsen, Geoffrey Love, Richard Sherry, Power and Energy Society General Meeting (PES), 2013 IEEE

Round Power Mode 14

Steady-State Operating Characteristic

PDC

Pref

Bipole PowerPole 2 PowerPole 3 PowerPmin POLE = 35MW

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Leve

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RP

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Pmin RP

Pmin RP

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-Pm

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Mon

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Round Power Operation

Monopolar Operation P3

Bipolar Operation

Monopolar Operation P2

Bipolar Operation

RP

Tra

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Queensland Australia SVCs - Overview

• Customer: Powerlink • Transmission network

service provider within Queensland

• SVCs (1987) provide voltage support to the electrical railway network

• Two refurbishments 1. Nebo SVC 2. Railway SVCs – Mobile /

containerized solutions

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Nebo SVC 16

• Rating: 340MW (+260/-80MVAr) / 275kV • Refurbishment of:

– Thyristor switched capacitor (TSC) and thyristor controlled reactor (TCR). Two stages:

• Replace damaged TSC valve first interfacing with old C&P

– Control and Protection System – Converter Cooling System

Railway SVC Mobile Solution

• Task: – Refurbishment of nine SVCs’ valve, cooling and C&P

systems with minimum impact on the ongoing system and train operations

• Solution: – Installation and operation of a mobile SVC system in

parallel to the refurbishment work – Minimum downtime for each station – After finishing each SVC refurbishment, the mobile SVC is

transferred to the next station

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Mobile SVC Solution Pictures 18

Refurbishment Procedure 19

4-6 weeks

2 x 13 hours shifts

3 days

2 x 13 hours shifts 2 days

Site Layout

• Site preparation • Equipment position • Power cable installation

– Six connections total – Each consisting of 6 cables

per bundle in parallel

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Site Layout Pictures 21

Connections to busbars Cable bundles connected on-site

Concluding Statements

• Refurbishments have their own unique set of challenges – Safety; minimize outages; space constraints,

interfaces with existing equipment, seismic, etc.

• Lifecycle extension of assets without complete replacement of site and equipment – Viable economical solution – Upgrade on performance / availability

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Thank you

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