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TRANSMISSION CHALLENGES IN THE DEVELOPMENT OF THE AYSÉN-SIC HVDC PROJECT

Juan Carlos Araneda, Gabriel Olguín

International Seminar on HVDC Systems, CIGRÉ SC B4 – SC B2Buenos Aires, Argentina – June 5th & 6th, 2008

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SING

•Transelec Transmission System

•Chilean Energy Market Situation

•HidroAysén Generation Project

•Aysén-SIC HVDC Transmission Project

•Feasibility StudiesPlanning studiesPower system studiesEngineering studiesTechnical solutionsEconomic evaluation

•Main Challenges

•Conclusions

Overview

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SING

Transelec is the largest electricity transmission company in Chile, concentrated on the highest voltage levels: 500 kV, 220 kV and 154 kV

Transelec owns 959 kilometers of transmission lines and 4 substations in the Northern Interconnected System (SING)

Transelec owns 7.244 kilometers of transmission lines and 44 substations in the Central Interconnected System (SIC)

Transelec is a private company owned by Brookfield Consortium, Canada.

SIC

Transelec Transmission System

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Chilean Energy Market Situation: HistoricalGDP, SIC and SING Energy Growth, 1996-2005

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

40,000

45,000

50,000

1996 1997 1998 1999 2000 2001 2002 2003 2004 20050

5,000

10,000

15,000

20,000

25,000

30,000

35,000

40,000

45,000

50,000SIC DemandSING DemandGDP

GWh

7.5%8.0% 5.3%

8.5%5.7% 4.1%

5.8%6.6% 3.2% -0.8%4.5% 3.4% 2.2% 3.3%

6.1%

7.6% 3.7%

7.0%

15.4% 15.1% 22.7% 3.4% 7.1% 5.5% 10.5% 7.2% 2.9%

billion Ch$

SING

SIC SIC GENERATION INSTALLED CAPACITY

19964859 MW

75%

19%

4%

1%

HydroCoalGasDieselOther

20068274 MW

57%

10%

26%

6% 2%

HydroCoalGasDieselOther

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Chilean Energy Market Situation: Prices

COAL+HYDRO COAL+HYDRO

Incentive to develop:New Coal fired plantsHydro resources at SICHydro resources in Aysén

NATURAL GAS(from Argentina)

GENERATION DEVELOPMENT COST

US$/MWh

70

45

30

1997 2004 2010 YEAR

Diesel

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TG DieselCentral CogeneraciónCentral CarbónCentral GNL/GNCentral Hidroeléctrica

Chilean Energy Market Situation: Future

Central Interconnected System (SIC):

Maximum demand 2007: 6.313 MW

2013: 8.700 MW (5.7 % growth per year)

2020: 13.000 MW

Installed capacity 2007: 9.148 MW

Hydro/Thermal Capacity: 60% / 40% (2007)

SIC

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

18,000

2008 2010 2012 2014 2016 2018 2020

MW

Demanda MáximaPotencia Instalada

Central Eólica

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PowerPower PlantPlant’s Location’s Location

XI XI RegionRegion ofof AysénAysén

Santiago

Aysén Region Hydroelectric Project

Producción Energía media anual:18.430 GWh/año

Pascua 2.1Pascua 2.15.110 GWh

Pascua 2.2Pascua 2.23.350 GWh

Potencia Instalada: 2.750 MW

Baker 1Baker 14.420 GWh

Baker 2Baker 22.530 GWh

Pascua 1Pascua 13.020 GWh

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Endesa’s Baker & Pascua River Studies

• First studies were developed in 1947.

• In 1961 and 1962 Endesa Chile installed measurement sections in the Baker and Pascua rivers, in order to have information at relevant points.

• In 1974 and 1975 a pre-feasibility study concluded that a 2,600 MW potential can be developed.

• In 1976 the “International Cooperation Agency of Japan”, by order of Government of Chile, studied the zone and obtained similar conclusions than those of Endesa Chile.

• In 1992 Endesa Chile re-studied Baker & Pascua for an Aluminum Project, looking for a 300 to 400 MW power plant.

• In 1998 the pre-feasibility studies of 1974 to 1976 were updated, with the same criteria of big plants with big reservoirs, unfriendly to the environment.

• In 2004-2005 Endesa considered the integration of the environmental management from the first design stages of the project, developing a strategy of respectful and responsible relations with the environment.

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SICSantiago

1000 km

1000 km

HidroAysén Power Plants:

2013 Baker 1 – 660 MW

2015 Pascua 2.2 – 500 MW

2017 Pascua 2.1 – 770 MW

2019 Pascua 1 – 460 MW

2020 Baker 2 – 360 MW

TOTAL 2750 MW

HVDC Transmission Project under Study

Puerto Montt

Cochrane

HidroAysén Generation Project

CHILE

www.hidroaysen.cl

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SICSantiago

1000 km

1000 km

HidroAysén Power Plants:

2013 Baker 1 – 660 MW

2015 Pascua 2.2 – 500 MW

2017 Pascua 2.1 – 770 MW

2019 Pascua 1 – 460 MW

2021 Baker 2 – 360 MW

TOTAL 2750 MW

HVDC Transmission Project under Study

Puerto Montt

Cochrane

Transelec Transmission

Project:

HVDC Line, 2000 km

Two HVDC converter stations

HidroAysén Generation Project plus Transmission

CHILE

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Aysén-SIC Transmission Project Studies

• Endesa, the largest generation company in Chile, and Colbún, the second largest generator in the SIC, are heading the studies of five hydro power plants with a total capacity of 2750 MW in the Baker and Pascua rivers of the Aysén region, in the south of Chile. In 2006 Endesa associated with Colbún to undertake the generation project together via a new company HidroAysén.

• Transelec signed an agreement with Endesa in November 2005 in order to develop the technical, economic and environmental studies for the design of the transmission project to connect the power plants to the SIC.

• During 2006 Transelec completed the conceptual engineering, including power system studies developed by HQ TransEnergie. In 2007 Transelec developed engineering studies, including system design studies performed by Teshmont, and also initiated the environmental impact study.

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Environmental challenges Minimize potential route through protected or sensitive areas Protect Patagonian trees Minimize landscape modification Identify and characterize local Flora & Fauna

Geographical challengesAreas exposed to boulders and erosion

Climatic challengesHeavy rainfall Low temperatures, strong winds, and heavy ice loads

1000

km

HornopirénPark

PumalínPark

QueulatPark

Cerro Castillo Reserve

Converter station in Cochrane

Río Simpson

Park

Corcovado Park

Las Torres Reserve

Project Challenges on the route from Puerto Montt to South (1000 km)

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Project Challenges on the route from Puerto Montt to South (1000 km)

Demographic challengesVery low population density which will impact the region during the construction period

Infrastructure challengesAustral Road is the only gravel road and mainly one way Bridges are very limited tonnageOnly one airport (Balmaceda), the rest being small airfields Coyhaique (40,000 inhabitants) is the main supplying center

1000

km

HornopirénPark

PumalínPark

QueulatPark

Cerro Castillo Reserve

Converter station in Cochrane

Río Simpson

Park

Corcovado Park

Las Torres Reserve

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Schedule of the Aysén-SIC Transmission Project

2010

January 2006

Start up studies

2009

Commissioning of the hydro power plants

Commissioning of the transmission project

2013

Studies stage

- Conceptual engineering

- Power system studies

- Environmental studies

Construction4 years

Terms of reference and

tendering

2021

Construction decision

Start up construction

- Basic engineering

- Additional studies

- Specifications

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HVDC bipolar line

SIC

Converter station Santiago

Converter station Cochrane

Planning of the Aysén-SIC Transmission Project

• Transmission capacity 2750MW and distance 2000 km• Transmission voltage ±500 kV or ±600 kV• Two alternative solutions: two bipoles or one bipole• Conductor size: 2x 42 mm or 4x42 mm respectively, under optimization • Reliability concern for design: 2021 Transmission/Max Demand= 20%

Transmission/Min Demand= 30%

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Power System Studies

Load forecast and generating expansion studies were performed to estimate most likely scenario of the main grid until 2021

Power system studies were developed by Teshmont

Transient stability studies were performed for monopolar and bipolar outages– The Aysén-SIC HVDC does not require continuous overload, there

would be enough static reserve to cater for a permanent monopolar outage

– The Aysén-SIC HVDC system will require a two hours overload to allow for the static reserve come into service. The overload requirement depends on the spinning reserve available to 2021

– The loss of the complete HVDC link will require a load shedding scheme to keep stability of the system

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Engineering Studies

Engineering and logistic studies to identify practical constrains – System studies were combined with logistic studies to identify main

practical constrains– How big and heavy can the single converter transformer unit be?– Should them be single-phase-two-winding or single-phase-three-

winding? – Converter Transformers physical dimensions and transportation

weight constrains determine the use of single-phase-two-winding over single-phase-three-winding transformers in alternatives where the weight is above 280 tons

– Thyristor current capability constrains the solutions to two valve groups or two bipoles if more than 4kA monopolar overload is required

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Technical Solutions under Study

Alternative A– a double bipolar system ±500kV or ±600kV with a 33% short time

monopolar overload (N-1) would need no load shedding – a low value current (1.8kA) would be injected into the electrode during 2

hrs until static reserve is brought in operation, electrode current would then reduce to 1.3kA

– the DC line would in principle be a single tower structure for two bipoles, but a risk analysis will identify zones where separation of the bipoles is recommended

Alternative B– a bipole ±500kV or ±600kV with a 100% short time overload capability – a low probability load shedding of up to 120MW for a monopolar forced

outage during minimum demand conditions – the DC line would be a single tower structure for both poles, but a risk

analysis will identify zones where separation of the poles is recommended

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SIC

SR: 210MW

1230 MW

+500 kV

-500 kV

675 MW

675 MW

AysénGeneration2750 MW

1350 MW 1230 MW

+500 kV

-500 kV

675 MW

675 MW

1350 MW

I2R ~ 60MW/polo

Bipolar operation

1.35 kA

1.35 kA

Numbers are just approximate

Transformers might be single phase three winding

Alternative A: Two bipoles

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SIC

SR:~210MW

Aysén

2750 MW

1350 MW

1350 MW

2370 MW

-500kV

+500kV

Bipolar operation Alternative B: One bipole

Numbers are just approximate

2.7 kA

Transformers might be single phase three winding

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Economic Evaluation

Aimed at finding the solution that minimizes the present value of the total systemic cost (TSC) – takes into account the investment cost associated to every solution,

Converter costs estimated from budgetary quotations and line cost estimated by line specialists

– the interests during construction,According to the staging of the project

– the electrical losses due to Joule and corona,Joule losses according to conductor selection, corona losses according to tower geometry and conductors diameter

– the energy not supplied According to expected number of monopolar outages and monopolar overload capability of the technical solution

iiiii ENSsolElecLsolINTsolINVsolTSCsol +++=

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Total Systemic Cost (TSC)

The total systemic cost is the present value of investment, electrical losses, interest during construction and expected energy not supplied

500kV solutions

MUSD

Monopolar overload capability

1.1 21.3

ENS

TSC

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Main Challenges

Definition of the transmission solution under several parameters:– Reliability requirements– Spinning reserve– Load shedding schemes– Investment costs

Construction difficulties: – Selection of the route of the transmission line

Topographic challengesEnvironmental impact authorizationGetting the concessionNegotiation of rights of way

– Ground electrodes locations– Converter transformer MVA/Tons transportation

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Conclusions

The Chilean southern hydro generation plus HVDC transmission projects represents a solution that competes efficiently againstcoal fired power plants.

The Aysén-SIC HVDC project will bring renewable energy (produced by HidroAysén) to the Central Interconnected System allowing most the Chilean territory to have access to hydro electricity and avoiding 16.000.000 tons of CO2 emissions per year.

Challenges …– Incorporating a new technology in the Chilean power system– Undertaking complex technical studies that ensure selecting the optimal

transmission solution – Designing a very long line with respect to the environment – Constructing a very long DC line which will cross untouched lands– Operating and maintaining the DC line and converter stations

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Acknowledgements

To HidroAysén for providing essential data regarding the generation project

To the Aysén-SIC HVDC Project Management team for collaborating with relevant feedback to this presentation

26www.transelec.cl

SC B4 contact:

Juan C. Araneda Gabriel OlguínPower System Development Manager Head of Engineering Studies, Aysén ProjectApoquindo 3721, 6th Floor Apoquindo 3721, 11th FloorSantiago, Chile Santiago, ChileTel. 56-2-4677166 Tel. 56-2-4677183jcaraneda@transelec.cl golguin@transelec.cl

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Biographical notes:

Juan C. Araneda is an Electrical Engineer graduated from Universidad Técnica Federico Santa María, Chile (1983) and Master of Philosophy from University of Manchester, UMIST, UK (2002). He worked in the distribution company Chilquinta (1984 to 1989), the generation company Colbún(1989 to 1994) and the transmission company Transelec (1994 to date). Currently he holds the position of Power System Development Manager in Transelec. He has participated as invited lecturer in several universities in Chile. He is a member of CIGRÉ and IEEE.

Gabriel Olguín is an Electrical Engineer graduated from Universidad de Santiago de Chile (1993), Master of Science from Federal University of Santa Catarina, Brazil (1999) and Doctor of Philosophy from Chalmers University of Technology, Sweden (2005). In Chile, he was with the distribution company Emec where he undertook a number of studies in planning and engineering (1995 to 2001). After obtaining his PhD he joined ABB Corporate Research, Sweden where he specialized in reliability studies, generator protection and HVDC. He is now with Transelec heading the engineering studies of the Aysén-SIC HVDC Project. He has participated as invited lecturer in universities in Brazil and Sweden. He is a member of CIGRÉ and IEEE.