Revisiting small signal stability analysis techniques in the context of stability study of a two-area multimachine power system

Regular load generation imbalances aka power system small disturbances in a network is always a matter of great concern which lead a major task of stability improvement to the technicians. Moreover when in place of single area network, there comes multi-area multi-machine power system, the overall dynamics becomes very integrated and complex to analyze. To suppress the oscillations of the system state variables i.e. to keep their deviation within some limit for a long period during small disturbances caused by load swinging or others, small signal analysis is needed first in place. Till date extensive researches has been done developing many toolboxes to analyze small signal stability like PSAT, SSST, PST, PAT, PSS/E, DigSILENT, EUROSTAG, SimPow and others. Among all PSAT is the most recommended and used software for the purpose. In this work a new algorithm has been developed to analyze the classical two-area four-machine system which is compared with PSAT's ( Power system analysis toolbox) result and literature's result. It came out that there's a significant amount of inaccuracy in PSAT's outcome and inter-area oscillation mode is found to be the most critical zone for analysis rather than local modes of oscillations in power system network.