Comparison of the performance of HVDC and HVAC overhead transmission lines for the Itaipu system

The transmission system associated with the Itaipu 14000 MW power plant comprises two parallel sets of transmission lines that are not connected at the generating station due to the frequency difference. The Brazilian transmission system is owned and operated by Eletrobras-Furnas, a large federal power utility. The scheme, designed in the 1970s, includes many features new at the time and continues to be a very significant part of the Brazilian energy supply. This paper describes the performance of the overhead power lines of the Itaipu transmission system during a recent period of fifteen years of operation. The two sets of transmission lines discussed are one of three 765 kV AC at 60 Hz and the other of two ± 600 kV DC. While mainly analysing data from the overhead transmission lines, some operating features, present use, and significant experiences are also discussed.