" Power system stability is the ability of an electrical power system, for a given initial operational condition,to regain a state of operating equilibrium after being subjected to a physical disturbance ,with most system variables bounded so that physically the entire system remains intact " P ower system engineering forms a vast and major portion of electrical engineering studies. It is mainly concerned with the production of electrical power and its transmission from the sending end to the receiving end as per consumer requirements, incurring minimum amount of losses. The power at the consumer end is often subjected to changes due to the variation of load or due to disturbances induced within the length of transmission line. For this reason the term power system stability is of utmost importance in this field, and is used to define the ability of the of the system to bring back its operation to steady state condition within minimum possible time after h