Analysis of Steady State Stability of a Two Machine System by the D-Decomposition Technique

The method of D-decomposition technique is used for the analysis of steady state stability of a two-machine system with the distant station provided with a fast acting electronic excitation voltage regulator using proportional signals of voltage and current and the first and second derivative of current signals. Analytical results are obtained on a digital computer of the type CDC 6600 for a typical two-machine system. Analysis is given for determining the voltage regulator gains for maximum alternator stability which to a great extent would overcome the often encountered difficulty of setting the regulator gains at commission stage by trial and error, until a good step response under open circuit condition is achieved. The effect of several parameters as also the electro-mechanical transient process of the receiving-end system represented by an equivalent machine of finite capacity on steady state stability of the system is investigated, for properly designing the parameters of the voltage regulator.