ITAIPU (Electrical Power Conversion)

ITAIPU

Having more power than 10 nuclear power stations it supplies the second largest city on the planet with zero-emission electricity since 1984, still being extended until 1991. 26% of the electrical power consumption of Brazil and 78% of Paraguay are supplied by ITAIPU

A 18 kV to 525 kV transformator for 825 MVATo increase the voltage ofthe generators, transformers with a capacity of 825 MVA and 768 MV, for 50 and 60 Hz respecitvely, were specified

Each year ITAPU generates 75 TWh of electricity (and avoids 67.5 million tons of carbondioxide emissions - compared to coal power plants). This electricity has to be transported to the areas of consumption and adapted to the local grid. Due to the existence of two frequencies, 50 Hz and 60 Hz, two independent power conditioning systems were installed.



Transformers

To increase the voltage of the generating units (because the transmission losses at higher voltages are lower), Single-Phase Transformer groups with nine banks of three single-phase 18 kV to 525 kV transformators (plus 1 reserve) rated 825 MVA for 50 Hz and 9 banks of 3 single-phase 18-525 kV transformators (plus 1 reserve) rated 768 MVA for 60 Hz were specified.

Transmission System

Considering that during the first years of operation of ITAIPU Parauay shall deliver to Brazil most of the power generated at 50 Hz to which it is entitled (for which it shall receive finacial compensation), and therefore the ferquencies in Brazil and Paraguay are different, it was decided to build for Brazil a composite transmisson system in EHV-AC (Extra High Voltage - Alternating current) for the 6300 MW at 60 Hz and in HV-DC (High Voltage - Direct current) for about 6000 MW of the 50 Hz part.



Power switches for high voltagesPower switches at the "Left Bank Substation" (FURNAS)

The HV-DC-system at FURNAS has a voltage of ± 500 kV, and is converted back into AC at Ibiuna near Sao Paulo, where most of the electricity is consumed.
The EHV-AC-system works at a voltage of 750 kV at transports the electrical power generated by the 60 Hz units by an 891 km transmission system, formed by three lines, to the Sao Paulo metropolitan area.
The electrical power of ITAIPU generated by the 50 Hz units and used in Paraguay (2-4 % of the total amount) is inserted into the Paraguayan grid by three 220 kV AC lines, conditioned through the "Right Bank Substation", located 2.5 kms from the ITAIPU powerhouse on Parauguayan territory.

The AC-DC rectifierThe FURNAS rectifier substation is accomplished by four lines of 500 kV. Output DC voltages are symmetrical ± 500 000 Volt SC.

6 300 MW of electrical power generated by the 60 Hz units is transported by an 891 km AC transmission system, formed by three lines of 750 kV