Spacer cable and ABC distribution lines. Long-term analysis

CEMIG-Companhia Energetica de Minas Gerais-is one of the largest electric-power installations in Latin America, situated in the state of Minas Gerais, southeast Brazil. It has some 5000 MW of generation capacity and distributes electric power among 4 million customers through 20000 km of transmission lines and more than 250000 km of distribution lines. To improve both the electric power supply quality and personnel safety, CEMIG has pioneered the use of aerial cable systems, such as the spacer cable and aerial bundled cable (ABC), in its Brazilian distribution system. As from 1991, it has been jointly working with a Brazilian cable manufacturer and an American spacer cable manufacturer to develop material technologies and construction patterns. This paper presents a comparative economic analysis of aerial cable systems and those in the conventional pattern: concrete poles, 2.4 m long wooden crossarms and bare conductors. The analysis takes into consideration the initial investment and operational costs of lines along with their lifetime period. The paper concludes with a recommendation of intensive utilization of spacer cable for medium-voltage lines and pre-assembled cables in low-voltage circuits. Only special applications should require the ABC lines.