Using PV systems and parking lots to provide virtual inertia and frequency regulation provision in low inertia grids

In this research, a novel formulation for smart frequency control and virtual inertia support in a low inertia grid is proposed. The approach takes advantage of EV parking lots and PV distributed resources abilities for this purpose directly or through aggregators. The model also considers governor control of the conventional plants in addition to the controllable loads, namely under-frequency load shedding devices. The model seeks to minimize the total amount of disconnected load in case of severe contingencies. Furthermore, the rate of change of frequency (ROCOF) is formulated and employed as another objective function. The control parameters are optimally tuned by Mixed Integer Linear Programming (MILP) model to minimize the amount of load shedding while satisfying the specified frequency constraints. Linearity of the model assures achieving the global optima and is suitable for large-scale real-life systems without convergence concerns. The proposed smart control scheme is implemented on the IEEE 39-bus system, where the simulation results demonstrate a dramatic decrease of load shedding from 0.1676 p.u to 0.1235 p.u for one of the cases by the incorporation of converter based frequency providers. The system ROCOF, moreover, is reduced from-2.94 Hz/s to-1.93 Hz/s which indicates the efficiency of the methodology.