In this paper an optimally designed PID controller equipped with Power System Stabilizer (PSS) for a Single Machine Infinite Bus (SMIB) system using linearized Modified Philip-Heffron's model is presented. The PSS design based on this model utilizes signals available within the generating station and doesn't require the knowledge about external system parameters like line impedance and infinite bus voltage. A new swarm intelligent Artificial Bee Colony (ABC) algorithm has been used to tune the PSS-PID parameters to enhance the small signal stability due to small variations in generation and loads. Various simulation results and comparisons over different loading conditions on a single machine infinite bus power system using ABC tuned PID-PSS show the superiority of ABC in designing the power system stabilizer for the model considered.

This letter brings out clearly for the first time the relative importance and weightage of some of the assumptions made by B. Stott and O. Alsac in their fast decoupled load flow (FDLF) algorithm on its convergence property. Results have been obtained for two sample IEEE test systems. The conclusions of this work are envisaged to be of immense practical relevance while developing a fast decoupled load flow program.