Impact of PLL and Virtual Inertia on Deregulated AGC System Integrated with Parallel AC/HVDC

This article investigates the impact of phase-locked loop (PLL) systems along with virtual inertia on system dynamics of a parallel AC/HVDC tie-line integrated two-area automatic generation control (AGC) system under a deregulated scenario. The multi-area AGC system comprises two thermal and hydro-gas in area-1, 2. An attempt is made to utilize a new secondary controller named the two-degree-of-freedom tilt-integral-derivative (2DOF-TID) controller. Its gains and PLL parameters are optimized by a novel meta-heuristic algorithm called a bird swarm algorithm (BSA). The system dynamics corresponding to the proposed 2DOF-TID are compared with 2DOF-PID, 2DOF-PI explored better system dynamics with a 2DOF-TID controller. The system dynamics are compared with AC alone, AC/HVDC, AC/HVDC tie-line incorporating with PLL, virtual inertia revealed the better performance of the latter. Moreover, the effect of variation in PLL parameter on the system dynamics are also analyzed and studies suggested that the obtained response at the nominal value of natural frequency (ω_n) and damping coefficient (ζ) reduces the subsequent oscillation and provides better dynamics other than varying condition.