Secondary control for reactive power sharing in droop-controlled islanded microgrids

摘要

This paper focuses on the islanded operation of microgrids. In this mode of operation, the microsources are required to cooperate autonomously to regulate the local grid\udvoltage and frequency. Droop control is typically used to achieve this autonomous voltage and frequency regulation. However,\uddroop control has real and reactive power sharing limitations when there are mismatches between the microsources. This\udpaper analyses the effect due to mismatches in the power line impedances connecting the source inverters to the microgrid.\udFrom the simulations results obtained, it was shown that the reactive power demand is unequally shared between the microsource inverters when there are mismatches between the power line impedances. To achieve equal reactive power sharing between the inverters, an external loop requiring low bandwidth communications was implemented in a central controller.\udSimulation results are presented showing the feasibility of the proposed solution in achieving reactive power sharing between\udthe inverters connected to the microgrid.