 cahora-bassa (previously spelled cabora bassa) is the name for an hvdc power transmission system between the cahora bassa hydroelectric generation station at the cahora bassa dam in mozambique, and johannesburg, south africa. ==history== the system was built between 1977 and 1979 and can transmit 1920&nbsp;megawatts at a voltage level of Â±533&nbsp;kilovolts and 1800&nbsp;amperes.compendium of hvdc schemes, cigrÃ technical brochure no. 003, 1987, pp89â94. thyristor valves are used, which unlike most other hvdc schemes are mounted outdoors and not in a valve hall. the valves are grouped into eight, 133&nbsp;kv six-pulse bridges in series at each end. the  long powerline runs through inaccessible terrain, so it is mostly built as monopolar lines  apart. in case of a single line failure, transmission with reduced power is possible via the surviving pole and return through the earth. cahora-bassa was out of service from 1985 to 1997 because of the mozambican civil war in the region. the project was beset with technological challenges, most notable of these being the adoption of solid-state rectification devices in a large-scale commercial installation. mercury-arc valves had been the de facto standard for hvdc up to this time. cahora bassa was the first hvdc scheme ordered with thyristor valves, though its operation was delayed. it was also the first hvdc scheme operational in africa, and
Energy_infrastructure_completed_in_1979 HVDC_transmission_lines