Rafael Bonchang HVDC Area Manager

Alstom GridEngland

Agenda

WHAT IS HVDC

ULTRA HVDC

VSC : A NEW TECHNOLOGY

PROJECT EXAMPLES

Why use HVDC?

• Transmission of bulk power where AC would be uneconomical

• Interconnection between systems which are non -synchronized or weak

• Improvement of AC system performance .

In many circumstances, it is economically and technically advantageous to introduce direct current (DC) links into the electrical supply syste m:

Types of HVDC Configurations

Basic HVDC Transmission

DC linkTransformer

F FHarmonic Filter

(Reactive Power )

ReceivingEnd

SendingEnd

Idc

Vdc

t

Idci

t

i

Iact

i

Iac

InverterRectifier

Point to Point – Overhead Line

DC Line

InverterRectifier

F F

ReceivingEnd

SendingEnd

t

i

t

i

t

i

Bulk Transmission

Point to Point – CableInverterRectifier

F F

ReceivingEnd

SendingEnd

t

i

t

i

t

i

Underwater or Underground

Back to BackReceiving

EndSending

End InverterRectifier

F F

t

i

t

i

t

i

Frequency changingAsynchronous connection

Why Use HVDC?

– Transmission >800km

– Submarine >50km– Frequency

conversion • 50-60Hz

– When synchronism of AC connections is impossible

Station Cost

DC

AC

Break EvenDistance

TransmissionDistance

The Perfect Tool

Up to 3 Times More Power

1850MW 1850MVA 5550MW

More Power Per Tower

DC DCAC

AC

DC

Charges and DischargesEvery Half Cycle

Only Charges the Cable Once

T7922

Power Transmission Via Cables

Surviving a Black Out

HVDC Price Trend

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 100 200 300 400 500 600 700 800 9001000MW

Pric

e (p

u)

Transmission Losses

0.2%

0.7%0.8%

0.0p.u 0.5p.u 1.0p.u0.0%

No-Load LossTransformer Converter Auxiliary

Load LossTransformerConverterFilter

Transmitted Power

HVDC Valves

Agenda

WHAT IS HVDC

ULTRA HVDC

VSC : A NEW TECHNOLOGY

PROJECT EXAMPLES

UHVDC Prospects 600kV-800kV

800 kV Valve

Wall bushing technology

Alstom 820 kV DC gas wall bushing

Agenda

WHAT IS HVDC

ULTRA HVDC

VSC : A NEW TECHNOLOGY

PROJECT EXAMPLES

What is VSC Transmission

• VSC = Voltage Source Converter• Capacitor normally used as energy

storage• VSC uses Transistor instead of

Thyristor technology

Comparison of Classical HVDC and VSC Transmission

ClassicHVDC VSC

Station Cost

Power Losses

Reliability / Availability

Control of Reactive Power

BLACK START

Footprint

Comparison of Classical HVDC and VSC Transmission

ClassicHVDC

VSC

Proven Experience (Service Life)

Power Range

Long Distance Transmission

Renewables conference, Manchester, Mar 2012

HVDC Off-shore Wind Farms

Off-shore wind farm

HVAC platform

HVDC platform

On-shore HVDC station

HVDC CABLE

Renewables conference, Manchester, Mar 2012

DC Grid Configurations: In-shore Point-to-point System

Renewables conference, Manchester, Mar 2012

DC Grid Configurations: Offshore Grid System

Agenda

WHAT IS HVDC

ULTRA HVDC

VSC : A NEW TECHNOLOGY

PROJECT EXAMPLES

South Korea - Cheju Island

• 400 MW, ±250 kVdc,

• 122 km submarine cable

• Completion 2013/2014Seoul

S. KOREA

Cheju Island

No. 1

No. 2KEPCO Returns to Alstom Grid for supply of a second,

larger HVDC project

Creating a National Grid in India

• 1 Chandrapur– 2 x 500MW, W-S regions

• 2 Visakhapatnam– 1 x 500MW, E-S regions

• 3 Sasaram– 1 x 500MW, E-W regions

2000 MW supplied by Alstom Grid

3

21

Middle East

• Interconnects– Saudi Arabia

380kV (60Hz)– Kuwait,

Bahrain, Qatar 400kV (50Hz)

• Rating : 3 x 600MW

• Ambient temperature 55°C

South America : BtB project

• Melo – Uruguay• Interconnects

– 500kV 50Hz Uruguay

– 525kV 60Hz Brazil

• 500MW pole• Turn -key project -

31 months

Montevideo

BRASIL

URUGUAYMelo

2 x 3150MW bi-poles

• ±600kV• 2375 km

Rio Madeira Project - Brazil

Rio Madeira

Sao Paulo

Power: 2x720MWVoltage DC: +/-300kVdcDistance 200 km

Phase 1: Interconnection in Sweden

Phase 2:Sweden to Norway

EAOW 25 January 2012

Sweden - South West

Champa India

• +/-800kV 3000MW Bipole

• 1300 km Line Between Champa and Kurukshetra

• Provision to include upgrade to 6000MW at a later date

www.alstom.com