Anti-islanding applied on a single-stage microinverter based on zeta converter for distributed microgeneration

The distributed microgeneration was regulated in Brazil in 2012. The connection of microgeneration systems to the utility grid can bring some challenges, like the islanding phenomenon. In this sense, an anti-islanding system must be designed to protect the microgeneration system, users, apparatus and the utility grid. If the islanding is not detected, some problems can occur, such as: degradation of power quality, threatens to safety of maintenance crews, damage to third party equipment connected to the same power grid, and during reclosing, if occurs a phase displacement between the grid voltage and the inverter output voltage some damage to the distributed generation system is expected, in the present scenario, the destruction of the microinverter is probable. In this paper will be presented study and the development of a very simple active islanding detection method dedicated to microinverters, which are used to inject into the mains the power generated from a single PV module. As an example, a microinverter based on Zeta converter working at DCM is discussed.