Operation Situation of Brazilian HVDC Transmission Grids and Several Enlightenments

HVDC project occupy an important position in Brazilian transmission grid and the construction of the project and putting it into operation have been experienced a long period, and its operation, maintenance, management and assessment possess indigenous characteristics. Due to the challenging of the policy of the operation, maintenance and supervision, the operation and the maintenance of Brazilian HVDC project has to face with the double stresses from ensuing high reliability of the HVDC system and decreasing operating costs. In general, the overall operation situation of the back-to-back HVDC project is satisfied, and in recent years the energy availability have been stayed over 99 percent. According to statistical data, the operating indices of Brazilian long-distance high-capacity Itaipú and Madeira HVDC projects are obviously influenced by the operation and maintenance conditions of different equipments, in which the time of interruption maintenance for valves and AC equipments is the main reason effecting the energy availability, the shortage of spare parts is the important reason leading to prolong the time for urgent repair of the converter transformer failure, besides, there is a higher proportion of self-supporting towers in the long-distance HVDC overhead transmission line and the tasks of line maintenance are arduous. Although the extensive management experiences of Chinese funded enterprises in the field of HVDC transmission technology and management powerfully support the construction, operation and maintenance of ±800 kV Belo Monte HVDC project, however the project implementation still has to face with the challenges in UHVDC technology localization, integration into existing power grid and operation due to the differences in the aspects of management system, operation pattern and standard system between Brazil and China.