Calculation of Audible Noise and Radio Interference for Unconventional High Surge Impedance Loading (HSIL) Transmission Lines

Corona discharges cause power loss, audible noise (AN), radio interference (RI), and television interference (TVI), all of which should be considered during transmission line design. Unconventional high surge impedance loading (HSIL) lines have been shown to have the potential to produce greater natural power than conventional lines and conventional HSIL lines. More than one conductor is used in conventional extra high voltage (EHV) lines, typically more than 300 kV, to form bundled conductors which reduce the electrical field on the subconductors and, as a result, reduce corona effects. In conventional lines, the number of subconductors symmetrically placed on a circle and bundle radius are determined based on corona effects considerations. Using a larger bundle circle and increasing the number of subconductors lead to greater natural power, resulting in conventional HSIL lines. Therefore, in conventional HSIL lines, bundled conductors are used not only to address corona effects but also to increase natural power. Using smaller conductors for conventional HSIL lines keeps costs close to conventional lines. In conventional HSIL lines, subconductors are still symmetrically placed on a circle while unconventional HSIL lines have subconductors placed at any point in space. Unconventional HSIL lines can lead to more natural power than conventional HSIL lines. In this paper, AN and RI for unconventional HSIL lines are calculated and discussed.