Optimally Located Subconductors and Phases to Achieve Transmission Lines With High Natural Power and Narrow Corridor Width

The number and location of subconductors in an overhead transmission line affect its inductance and capacitance, leading to a change in its natural power. Traditionally, for conventional transmission lines around above 300 kV, more than one conductor has been used as bundles for each phase. The subconductors in these bundles have been placed in a symmetrical arrangement in space. Conventional high-natural power lines are designed to have a greater number of subconductors per bundle and a greater bundle radius than a conventional line at the same voltage level. In this paper, new configurations with various numbers of subconductors for unconventional high natural power line designs are studied. The term “unconventional” denotes that the subconductors are not arranged in space in the traditional symmetrical configurations used in the conventional lines and conventional high natural power lines mentioned above. Instead, their optimized locations are found so that their natural power can be further increased. The aim is to enhance the natural power of these new line designs via optimally located subconductor configurations to achieve narrower corridor width as well. Moreover, for these optimally designed transmission lines, 1) corona loss, 2) audible noise, 3) radio and television interferences, 4) location of shield wires, and 5) electric and magnetic fields under these lines are calculated and compared with them for conventional lines. It has been shown that for our newly designed unconventional line with $N=8$ , the SIL achieved is 1414.70 MW, which is a 43% increase compared to that of the conventional line; and the reduced line width of 9.7 m is only 40% of that of the conventional line. Consequently, this leads to the mentioned unconventional line having a natural power density of 3.38 times that of the conventional line.