Phase-Selection Study For Double-circuit Transmission Lines

Double-circuit transmission lines share the same tower, It has lots of advantages such as large transmission capacity, save more land resources and fast construction speed , in our modern grid this way of transmission has already widely used. But the double-circuit transmission lines exist 98 sorts of during cross line fault, and the total fault reach 120, it is very important to study fault selection correctly especially apply to double-circuit transmission lines.Six-sequence components method and module components transformation are both the way of decoupling double-circuit transmission lines with line to line inductance and phase to phase inductance. In this paper, using this two methods to analyze fault characteristics in double-circuit transmission lines. The study shows, When it occurs single-circuit lines fault or during cross line fault between the same phases, module components characteristics are obvious, six-sequence components have the advantage of analyzing during cross line fault between different phases. Therefore, a new relatively simple and practical phase selector scheme with using the module value and phase relationship was proposed.Set up 500kV double-circuit transmission line with PSCAD/EMTDC, the results of simulation show that the fault phase selector can be free from the influences of the operating conditions and the various fault conditions.