Enhancing grid frequency regulation in low inertia modern multi-area power systems using cascaded non-integer control approaches with BESS-based virtual inertia

In modern power systems, the integration of inverter-based renewable energy sources has significantly reduced system inertia, leading to heightened frequency fluctuations and potential instability within multi-area interconnected microgrids. To counter this, a virtual inertia and damping controller utilizing battery energy storage, leveraging the virtual synchronous generator concept is proposed in this paper. This controller supplements inertia by modulating active power flow, thus stabilizing frequency during high renewable energy source penetration periods. Additionally, to enhance load frequency control, a cascaded controller combining adaptive neuro-fuzzy inference system-assisted fractional-order PID with a nonlinear FOPI controller is introduced. It should be noted that improper controller parameters can worsen frequency deviations and system stability. Hence, a whale optimization algorithm optimizes control parameters using the integral time absolute error based objective function. Simulation studies on a modified IEEE 10-generator 39-bus power system, considering various disturbances like stochastic load-generation, nonlinear generation behaviours, and time delay, validate the effectiveness of the proposed controller. Comparative analysis demonstrates the superior resilience of the cascaded control approach in managing contingencies within low-inertia power systems, with a remarkable performance improvement of 87.9811% compared to existing control methods.