A new 500MW frequency converter station to exchange power between Uruguay and Brazil

The power transmission utility in Uruguay (UTE) has commissioned an HVDC station at the Melo substation to provide a link to the transmission system in Brazil. Uruguay´s indigenous hydro power resources have been almost fully exploited and can be an un-predictable source due to prolonged dry seasons. By linking to the much larger Brazilian power system, Uruguay will be able to have access to large energy resources and thus provide a medium term solution to their generation issues, ensuring security of supply to their customers. An existing HVDC converter station, which was built in the late 1990´s at Rivera in Uruguay, inter-connects the power networks of the two countries. However, this station has limited capacity of only 70MW and can not meet the future energy requirements of UTE. This paper will describe the complete AC and DC inter-connector project between the San Carlos 50Hz substation in Uruguay, via a 325 km 500kV AC transmission line to the Melo converter station and a 116 km 525kV AC transmission line to the Candiota 60Hz substation in Brazil where some of the 60 Hz side harmonic filtering is installed. This is a full turnkey project with a new 500kV sub-station on the 50Hz side and a new 525kV substation on the 60Hz side to supply the converter station. At the San Carlos sub-station AREVA is responsible for the design and supply of the 500kV equipment to connect the transmission line to the substation. At the Candiota sub-station the harmonic filters and the associated equipment to connect the transmission line to the substation are being provided by AREVA. Although equipped with local and remote control facilities, the Melo station is designed such that it can be unmanned in normal operation. The project, which was awarded in early 2009, is due to be completed in a 31 month period.