A new control method for power quality improvement in island microgrids

This paper presents a new method for power quality improvement in four-wire islanded microgrids (MG). The main studied aspects related to power quality are voltage - frequency control, and unbalances compensation. While the voltage and frequency control were studied before by the authors of this paper, the unbalances compensation is the main topic. Two unbalance compensation controllers are used, for active and reactive powers. The compensation is based on a dump load (DL) and static compensators (STATCOM), which ensure the balance of the active and reactive powers between the MG phases. The DL ensures mainly the frequency control and it is used for active power balancing between phases, too. The STATCOM accomplishes only the redistribution of the reactive power unbalance between phases, not the power factor correction. Therefore, its rated power is small, according to the maximum reactive power unbalance that can be expected in the MG.