D-PMU Based Secondary Frequency Control for Islanded Microgrids

Abstract

This paper proposes a secondary frequency control approach for distributed energy resources (DERs) in networks operating in stand-alone mode; i.e., islanded microgrids. The proposed approach takes advantage of the high resolution, low latency, and time-stamped synchronized measurements of the distribution-level phasor measurement units (D-PMUs) to iteratively adjust the generators contribution, considering the D-PMUs derived active power information, in a way that improves the dynamics of the islanded microgrid frequency regulation. These adjustments are performed using a novel adaptive time-variable droop characteristic capable of significantly speeding-up the secondary frequency regulation, mitigating oscillations, and reducing the frequency nadir. The proposed secondary frequency control can be held after the stabilization of the primary control, as well as simultaneously with the primary frequency regulation. Results show the effectiveness of the proposed approach in significantly improving the frequency regulation of islanded microgrids.