Study of super-bundle and low-reactance phasings on untransposed twin-circuit lines

The authors compare the characteristic of low-reactance (LR) phasing, including a single-circuit operation, with that of a more popular super-bundle (SB) phasing of untransposed twin-circuit lines and also with that of a transposed twin-circuit line. Using results calculated by the EMTP and an analytical formula for the symmetrical components of phase currents, it is found that the zero and negative-sequence components of phase currents, the electric field strength, and the inducing current of steady-state electromagnetic induction to a telecommunication line are reduced by between 30% and 60% if the LR phasing is adopted in preference to the SB phasing. It is found that the analytical formula is satisfactorily accurate compared with the EMTP result and can explain the characteristics of various phasing arrangements