A New Islanding Detection Technique for Distribution System during DG Interconnections

In this article, a new 'dq0' transformation based islanding detection scheme for power distribution system with Distributed Generation (DG) interconnections is presented. The proposed scheme is based on conversion of current and voltage samples of all phases into 'd', 'q' and '0' components using 'dq0' transformation. PSCAD/EMTDC software package is used to generate varying islanding and non-islanding events. Various islanding conditions have been simulated by disconnecting the main circuit breaker with different value of reactive and active power mis-matches. On the other hand, different non-islanding conditions such as short-circuit on an adjacent feeder, switching (ON/OFF) of load, switching (ON/OFF) of transformer, energization /de-energization of medium transmission lines, and switching (ON/OFF) of capacitor bank in the network have also been simulated. The simulation results indicate that the proposed scheme is not only capable to detect islanding condition within half a cycle after the inception of event but also avoids nuisance tripping during diversified non-islanding events.