Reactive Power Management in Islanded Microgrid – Proportional Power Sharing in Hierarchical Droop Control

A microgrid (MG) is a local energy system consisting a number of energy sources (e.g. wind turbine or solar panels among others), energy storage units and loads that operate connected to the main electrical grid or autonomously. MGs provide flexibility, reduce the main electricity grid dependence and contribute to change the large centralized production paradigm to local and distributed generation. However, such energy systems require complex management, advanced control and optimization. Moreover, the power electronics converters have to be used to correct energy conversion and interconnected through common control structure is necessary. Classical Droop Control system is often implemented in microgrid. It allows to the correct operation of parallel voltage source converters (VSI) in grid connected as well as islanded mode of operation. However, it requires complex power management algorithms, especially in islanded microgrids, which balances system, improves reliability. The novel reactive power sharing algorithm is developed, which takes into account the converters parameters as apparent power limit and maximum active power. The developed solution is verified in simulation and compared with other known reactive power control methods.