Coordinated Power Reserve Control of PV Sources For Frequency Restoration in Power Electronics Dominated Grid

Abstract

This paper presents a droop-power allocation optimizer (D-PAO) inspired control scheme to mitigate frequency excursions in a power electronics dominated grid. This scheme leverages the photovoltaic (PV) sources’ flexible power reserve ability to restore frequency during sudden imbalances in power demand-supply, while minimizing the size of the required energy storage systems. Application of PV power reserve in a distributed PEDG network comprising of sources with various capacities, reserves and other constraints has not been investigated so far. The proposed scheme accommodates these uncertainties in the estimation of the required active power $(\Delta P)$. Moreover, the PAO module optimally allocates the estimated $\Delta\mathbf{P}$ demand among all the sources in the cluster, based on the available power reserves while also minimizing losses. In response, the power electronics converters/inverters in the PEDG adjust their power levels and support the network in restoring the frequency in a timely and cost-effective manner. The PAO module eliminates the droopbased coordination requirement and their associated drawbacks. Case studies illustrate the superiority of the proposed scheme over the conventional droop-based frequency restoration approaches.