Steady-State Stability in Transmission Systems Calculation by Means of Equivalent Circuits or Circle Diagrams

The maximum load on a proposed transmission system must be within the steady-state power limit of the system for stability of operation. Two methods of calculating steady-state stability are given in detail and illustrated by examples. (1) The given transmission system is replaced by a simple equivalent system; then the steady-state power limit of this equivalent system is determined graphically. (2) By means of a circle diagram the system is tested for stability with the maximum proposed load on the system. All formulas from published references necessary for the calculations are included and all calculations are given in full so that similar studies can readily be made by an engineer who has not previously made a study of the subject of stability.