Multiple features based anti-islanding protection relay for distributed generations

A multiple features based passive islanding detection technique using S-transform and decision tree is proposed in this paper. It consider synchronous as well as inverter based distributed generations interfaced to micro-grid. The technique involves extraction of different statistical features of frequency contour obtain by performing S-transform with the current signal retrieved at target distributed generation location and builds the decision tree for islanding and non-islanding classification. Extensive simulations are carried out for wide variations in system loading and power mis-match during islanding, and a decision tree is built for effective islanding detection for both synchronous and inverter based distributed generations in microgrid. Performance of the proposed anti-islanding technique is compared with existing rate of change of frequency and rate of change of voltage relay. It provides improved performance at lower end power mis-match.