Fig. 3From: Cascade controller based modeling of a four area thermal: gas AGC system with dependency of wind turbine generator and PEVs under restructured environmentComparison of performance of PID, PI-PD, PD-PID and PIDD-PI during bilateral transactions. a Frequency deviation in Area 1. b Tie-power deviation in the line connecting Area 1 and 4. c Tie-power deviation in the line connecting Area 3 and 4. d Power generation in thermal plant and WTG unit in Area 1Back to article page