Transient stability analysis comparison of double 3-ph to 6-ph converted transmission line for symmetrical and unsymmetrical faults

Abstract

It is well known that 3-ph double circuit A.C transmission line is designed for bulk power transmission system and to enhance the stability limit, instead of 3-ph double circuit line 6-ph line is used and proved to have more steady state and transient stability limits. This paper deals with load flow and comparison of transient stability of double 3-ph to 6-ph changed transmission lines for symmetrical and unsymmetrical faults using nine-bus power system. For the considered system by using Gauss Siedel's iterative method, few inputs values are given in p.u. and for the transient stability analysis modified Euler's method is used. the values of voltages, angles, active and reactive power are found at all buses at different times from the fault occurrence time. swing curves are drawn as output by giving different fault clearing times by which critical clearing angles are found for 3-ph and 6-Ph changed transmission lines and "c++" language is used for analyzing these lines.