Grid resilience enhancement of photovoltaic systems via Lyapunov-validated active–reactive power coordination and inverter oversizing

The rapid integration of photovoltaic (PV) systems into distributionnetworks creates significant challenges in managing power fluctuationsand maintaining voltage stability. While conventional maximum powerpoint tracking (MPPT) techniques improve energy extraction, they arelimited in mitigating active power oscillations and providing fastreactive support during grid disturbances. This study introduces anactive-reactive power coordination framework with modest inverteroversizing, designed to enhance both steady-state and dynamicperformance of grid-connected PV inverters. The proposed approachcombines Incremental Conductance (INC)-based MPPT with dynamicreactive power control under apparent power constraints, and itsstability is rigorously evaluated using small-signal, frequency-domain,continuation power flow, and Lyapunov analyses. Simulation results fora 50 kW dual-stage PV system under diverse operating scenarios-including irradiance variations, load disturbances, voltage sags, andshort-circuit faults-demonstrate that the method suppresses poweroscillations to within ±0.9%, regulates PCC voltage within ±3%,increases feeder loadability by 15%, and reduces on-load tap changeroperations by 40%. These findings confirm that Lyapunov-basedstability assessment, together with coordinated active-reactive controland oversizing, offers a practical pathway for improving grid reliabilityand resilience in PV-rich distribution systems.