Distribution Static Compensators and their Applications in Microgrids

Microgrids are clusters of distributed energy resources, energy storage systems and loads which are capable of operating in grid-connected as well as in offgrid modes. In the off-grid mode, the energy resources supply the demand while maintaining the voltage and frequency within acceptable limits whereas in the gridconnected mode, the energy resources supply the maximum or nominal power and the network voltage and frequency is maintained by the grid. This chapter first summarizes the structure and control principles of microgrids. It then briefly introduces the structures and control perspectives of distribution static compensators (DSTATCOMs). Finally, some applications of DSTATCOMs are discussed in microgrids. The introduced applications are power quality improvement due to the presence of nonlinear and unbalanced loads, voltage regulation and balancing, and interphase power circulation in the case of the presence of single-phase energy resources with unequal distribution amongst phases. Each application is illustrated by examples, realized in PSCAD/EMTDC.

Keywords: Distribution static compensator (DSTATCOM), Interphase power circulation, Load compensation, Microgrid, Voltage regulation.