Comparison of adaptive P/ω droop strategies for intermittent energy sources in emergency islanded operation

Islanded operation is a key tool to improve the reliability and operational resilience of distribution grids. To enable islanded operation with minimal hardware changes, it is convenient to operate already installed PV units in droop-controlled grid-forming mode. This paper analyzes the main adaptive strategies that allow to implement the P/ω droop principle in double-stage units interfacing intermittent energy sources. The advantages and unwanted behaviors of each strategy are illustrated through a thorough simulation-based evaluation, which leads to a set of guidelines for the design of novel improved adaptive P/ω droop strategies.