Frequency Control Strategy of the Islanded Microgrid

The power imbalance between micro-sources and loads in the microgrid will result in the frequency fluctuations. In order to maintain the frequency stability of the islanded microgrid, and make full use of the generation advantages of each micro-source, a frequency control strategy of islanded microgrid based on the hierarchical control is presented in this paper as to PV-ESS microgrid that has high commercial value. The system frequency is divided into four areas according to its dynamic characteristics, and stable frequency control can be realized through such control strategies as active regulations by energy storages or photovoltaic systems, high-frequency generator tripping and low-frequency load shedding as to different frequency areas. It is verified from case analysis that the proposed strategy can effectively coordinate and control different types of micro-sources in microgrid to balance the system power and maintain the system frequency stability.