Coherent swing under-frequency transient stability for renewable sources islanded micro-grid

Abstract

Renewable Energy Sources micro-grids experience operational challenges due the unpredictable weather patterns, requiring continuous demand control schemes, which are detrimental to both customers and the micro-grid operator. Optimal unit commitment plans coupled with a synthetic inertia system, that is, distributed renewable energy storage (DRES), are considered to lower power imbalances and thus contributing to frequency transient stability. This research models a renewable energy micro-grid with solar PV, wind turbine, hydro and a geothermal power plant. The transient stability study during times of severe power imbalances shows the micro-grid is unstable during such a time. Particle swarm optimization is developed to commit the units in an optimal scheme that considers load flow power losses and DRS in a multi-objective function. This improves the control and operation of the micro-grid, minimizing frequency fluctuations caused by power imbalance, at times of severe shortage of generation from intermittent renewable sources.