1. Efficient Energy Transmission using HVDC
ENERGY EFFICIENCY
IDB
SÃO PAULO – SP
15 September2008
Welcome
Efficient Energy Transmission using HVDC
John Graham

2. Why transmit electric energy?
To connect generation to load.
To optimise generation prices within the market.
To increase the firm energy in hydroelectric systems.
Why transmit electric energy with HVDC?
More efficient.
More robust.
Less environmental impact.
Smaller Right of Way
2 conductors vs 3

3. Hydraulic Basins
Why transmit electric energy?
To connect generation to load.
To optimise generation prices within the market.
To increase the firm energy.
In order to be efficient the transmission should have minimum electrical losses.

4. In order to be efficient the transmission should have minimum electrical losses.
Losses = I2R, Square of the Current.
Increase the voltage in order to reduce Current.
Long distance and/or high power tends to favour higher voltages.

5. Basic Considerations : Voltage Level
Comparison between HVAC and HVDC shows similar behaviour.
The maximum voltage stagnated due to market reasons.
Now the market has changed!
Lower losses
Less lines
More efficient
Voltage Level HVAC e HVDC
Basic Considerations : Voltage Level

6. Chinese system planning for 2012
Three HVDC links in
800 kV in construction
3 x 2000 km.
Power to 7200 MW.
650 km of 1000 kV Three GIS stations
Chinese system planning for 2012
State Grid of China

7. Renewable EnergyAlternatives
Biomass
All require transmission both
efficient and flexible
Wind
Solar
Hydro
Sol

8. Europe: Renewable Energy Vision
Hydro power
Solar power
Wind power
DC transmission
Wind
300 GW
km sq
5000 x 10 km
Hydro
200 GW
Europe
Europe: Renewable Energy Vision

9. EON Netz, NordE.ON 1, 400 MW HVDC Light
400 MW off shore
converter
128 km sea cable
75 km land cable
400 MW converter
EON Netz, NordE.ON 1, 400 MW HVDC Light

10. International exchanges
Challenge to integrate long distance interconnections. ▲ ▲ ▲
Wind Power
5000 MW
Future
Hydro generation ▲ ▲
1000 km
Hydro generation: Long distances
Thermal: Close to the loads
Wind power: North coastal
International exchanges
CCGT
Coal

11. Why transmit electric energy?
To connect generation to load.
To optimise generation prices within the market.
To increase the firm energy in hydroelectric systems.
Why transmit electric energy with HVDC?
More efficient.
More robust.
Less environmental impact.

12. Market today Efficiency Environment Reliability Market tomorrow
Drivers
Drivers
Efficiency
Environment
Reliability
Market tomorrow

13. Number of lines in parallel to transmit 7000 MW
500 kV ac. RoW 5 x 80m = 400m
2000km = 800km2
800 kV ac. RoW 3 x 100m = 300m
2000km = 600km2
600 kV dc. RoW 3 x 75m = 150m
2000km = 300km2
800 kV dc. RoW 1 x 80m = 80m
2000km = 160km2
The information in the table on the previous slide has been illustrated here to give an impression of the right-of-way requirements and environmental impacts for different transmission capacities and system voltages.
The effectiveness of HVDC transmission lines at higher voltage levels is clearly demonstrated.
Less clearing of forest to prepare Right of Way

14. La HVDC conserva bosques y terrenos
Cables HVDC
La HVDC conserva bosques y terrenos
La corriente directa require menos líneas para la mísma potencia
La corriente alterna require corredores anchos

15. Why use HVDC Transmission?
1. Lower investment costs
2. Long Distances
3. Lower electrical losses
4. Asynchronous interconnections
5. Flexibility by control
6. Limitation of sort circuit currents
7. Lower environmental impact
It can be seen that all these
Reasons are applicable in Brasil

16. Itaipu 2x7000 MW 3 EHVAC Lines 2 HVDC Lines
765 kVac
About 70% Guyed Vee
Average weight 8500 kg
16 m Phase spacing
Conductor 4xBluejay 564 mm²
35 Insulators
2 HVDC Lines
± 600 kVdc
About 80% Guyed Mast
Average weight 5000 kg
Conductor 4xBittern 644 mm²
32 Insulators 510 mm creep
16 m pole spacing
Here Itaipu shows us the economy in transmission lines obtained by the use of HVDC..
ABB Scope of Work: Tower engineering for both lines. Tower supply and construction for large part of both.
Commercial operation in Today still the highest voltage in HVDC

17. Foz do Iguaçu Converter Station

18. HVDC systems in North America
Asynchonous borders
Canada - USA
HQ – NEPOOL
In a mature power system, in this case North America,
Between synchronous areas
Generation connection
Interconnection
Asynchronous Interconnection
Generation Outlet
Interconnection
HVDC systems in North America

19. HQ – NEPOOL Multi-terminal
Corrente Continua em Multi-terminal
HQ – NEPOOL Multi-terminal
Technical Data:
Commissioning year:
Power rating: 2000 MW (multiterminal)
DC voltage: ± 450 kV Length of overhead DC line:
1480 km Main reasons for choosing HVDC system:
Asynchronous link
Multi-terminal example: Hydro Quebec – New England

20. Blackout Aug 14, 2003 Source: Public Power Weekly, August 25, 2003
200 MW
500 MW
147 MW
Blackout Aug 14, 2003 Source: Public Power Weekly, August 25, 2003

21. Interconnection of the Rio Madeira generation HVDC
RoW 150 m
or 350 km2

22. Interconnection of the Rio Madeira generation Hybrid
RoW 235 m
or 560 km2

23. Hydroelectric expansion 2007 - 2016
N – S IV
Tocantins
Wind Power
5000 MW
Belo Monte ▲ ▲ ▲ ▲ ▲
Tele Pires
1000 km
Das Mortes
Energy exchange is facilitated by the flexibility of HVDC.
More security with control avoiding cascade tripping.
Lower environmental impact due to reduced RoW.
Rio Madeira
Taking the flows
Sul - SE
Future CCGT
Hydroelectric expansion

24. Why transmit electric energy?
Reasons to use HVDC links in Brasil
1. Lower investment cost
2. Long distances
3. Lower losses
4. Asynchronous interconnections
5. Flexibility by control
6. Limitation of short circuit currents
7. Lower environmental impact
Why transmit electric energy?
To connect generation to load.
To optimise generation prices within the market.
To increase the firm energy in hydroelectric systems.
Why transmit electric energy with HVDC?
More efficient.
More robust.
Less environmental impact.