Bacterial foraging based FOPID controller in AGC of an interconnected two-area reheat thermal system under deregulated environment

The paper deals with application of a bacterial foraging (BF) based fractional-order PID (FOPID) controller in automatic generation control (AGC) of a two equal area thermal system considering single stage of reheat turbine and appropriate generation rate constraint (GRC) under deregulated market environment based on bilateral policy scheme. Several integer-order (IO) controllers such as I, PI and PID controller have been tried out and dynamic responses so obtained are compared with FOPID controller to assess the best controller. Critical examinations clearly reveal that FOPID controller having five tuning parameters are quite robust and superior to conventional IO controllers in terms of settling time, reduced oscillations and peak overshoots. Further, investigation have been carried out for the selection of suitable value of speed regulation parameter (R) for governor (primary controller) using FOPID controller (secondary controller). Integral square error (ISE) criteria have been used as performance index to design the optimal controller.