Participation of DERs to the Bottom-Up Power System Frequency Restoration Processes

This paper studies the transient behavior and frequency stability of a grid with a large share of distributed energy resources (DERs) during a bottom-up restoration process. This work is motivated by a real-world restoration process, during which the tripping of the DER frequency protections led to the frequency instability and finally to the collapse of the system. The main contribution of the paper is the proposal of a DER control strategy based on the estimation of the rate of change of frequency and fast frequency regulation. A comprehensive stochastic analysis in time domain shows that the proposed control effectively prevents the occurrence of the instability during the restoration process.