Generalised operating characteristics of e.h.v. transmission lines

Adopting the representative average values of inductive reactance and susceptance of e.h.v. lines, the common power-circle diagrams have been generalised so that they become applicable to each and every case of e.h.v. lines having up to four conductors per phase. With the help of these generalised power-circle diagrams, it is possible to assess and predict very closely the operating characteristics of the transmission lines, even before their detailed designs are evolved and actual parameters are known. They will thus prove of great help in the planning and design of power systems, for comparing relative merits of different types of transmission lines under any given set of conditions. These generalised diagrams have been used to compare the two well known concepts of power-transmission capability which have been found to be in good agreement with each other. This proves their relative validity by mutual corroboration. Typical operating characteristics of 400kV lines have also been worked out, and pertinent observations on the various aspects have been recorded so as to be of ready help to planning and design engineers.