IEEE 2011 Electrical Power and Energy Conference

Prof. Maria Cristina Tavares B.Sc. Ricardo Borges

1  

BRAZIL

IEEE 2011 Electrical Power and Energy Conference

Introduc)on  

2  

  With the constant increase on Brazilian electric energy consumption, it arises the need for more energy generation

  High hydroelectric potencials (more than 100 GW) where identified on the Brazilian North Region

  Large hydroelectric complexes will be built in this region

  Distances for energy transmission from these generation plants to load centers (South-Southeastern Region and Northeastern Region) are around 2500 km

IEEE 2011 Electrical Power and Energy Conference

IEEE 2011 Electrical Power and Energy Conference

Introduc)on  

4  

IEEE 2011 Electrical Power and Energy Conference

Introduc)on  

5  

IEEE 2011 Electrical Power and Energy Conference

Basics  Caracteris)cs  of  a  HWL  Transmission  Line  or  AC-­‐Link  

6  

 Voltage gain at no-load

 No need of reactive compensation

 Low cost line

IEEE 2011 Electrical Power and Energy Conference

Compara)ve  Cost  Analysis  

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IEEE 2011 Electrical Power and Energy Conference

Future  Largest  Hydroelectric  Plants  

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27 GW will be installed => 23 hydro plants with capacity > 1 GW

IEEE 2011 Electrical Power and Energy Conference

Voltage  along  the  Line  

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 Several power flows

IEEE 2011 Electrical Power and Energy Conference

Test  Transmission  System  

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 To give some support a real test was proposed.

 A set of existing 500 kV similar transmission lines was identified, forming a 2600 km test long line.

 This test is described and analyzed in a companion paper.

IEEE 2011 Electrical Power and Energy Conference

Line  Parameters  –  60  Hz  

Sequence Resistance (Ω/km)

Inductance (mH/km)

Capacitance (µF/km)

Zero 0.38705 1.31743 3.7779

Positive/Negative 0.00832 0.17442 9.7008

 800 kV line

 8 conductors/phase

 Positive sequence surge impedance 134.2 Ω

 Νatural power is 4.8 GW

 Line with 2600 km long

IEEE 2011 Electrical Power and Energy Conference

Small  Loads  Connec)on  

  As the AC-Link has a high natural power it can stand small power extractions through its length without an important compromise of its operation.

  Consumption estimative = 40 MW on a 100,000 inhabitants city.

  Studies were carried out for 50 MW block extractions through the line (important amount of power for the region where the line is going to pass).

IEEE 2011 Electrical Power and Energy Conference

Small  Loads  Connec)on  

  Line was considered to be in steady-state:

 Voltages on sending and receiving ends were maintained within 0.95 pu and 1.05 pu.

 Power was injected, with unitary power factor, on the sending end of the line

IEEE 2011 Electrical Power and Energy Conference

Connec)on  of  Different  Loads  on  Different  Points  along  the  Line  

Load connected near the sending end

Load connected in the line center (worst case)

IEEE 2011 Electrical Power and Energy Conference

Line  TransmiJng  Different  Amounts  of  Power  

  The line is not going operate at full load the whole year

  50 MW is an important amount of power for the region where the line is going to cross

  Based on that, some cases were simulated with 50 MW drain, with the line transmitting different amounts of power

IEEE 2011 Electrical Power and Energy Conference

Line  TransmiJng  Different  Amounts  of  Power  

Load connected 256 km away from the line sending

end

Load connected 684 km away from the line sending

end

IEEE 2011 Electrical Power and Energy Conference

Load connected 1344 km away from the line sending

end

Load connected 1772 km away from the line sending

end

Line  TransmiJng  Different  Amounts  of  Power  

IEEE 2011 Electrical Power and Energy Conference

Conclusions