Microgrid Stability: A Review on Voltage and Frequency Stability

Microgrids (MG) take a significant part of the modern power system. The presence of distributed generation (DG) with low inertia contribution, low voltage feeders, unbalanced loads, specific X/R ratio and the low short-circuit power values makes the observation of the MG stability aspects different from the conventional bulk power system stability. This paper presents a review on the voltage and the frequency stability control methods applicable on the MGs. A brief overview of classification of MGs and MG operating modes is given. Some methods of voltage and frequency control are proposed and hierarchical frequency control is presented.