Islanding Detection for Photovoltaic Inverters Using the Sandia Frequency Shift Method

The connection of inverters for distributed generation photovoltaic systems to the distribution network creates situations of risk to the loads that are connected to the point of common coupling (PCC) and personals who maintain the power grid. A risk that should be avoided is the supply of electricity, by one or more inverters, to the distribution network after disconnecting the main power grid. The isolation of distributed generation systems that continue to supply the power required by the load at the PCC is known in the literature as islanding. The unintentional islanding can be avoided by using islanding detection techniques. This paper describes an anti-islanding detection method used for prevention against unintentional islanding of the distributed generator. The main focus is the study, implementation and analysis of the Sandia Frequency Shift method based on the IEEE 929-2000 standard.