Smart inadvertent islanding detection employing p-type PMU for an active distribution network

In the smart-grid paradigm, since distribution systems are controlled by various independent operators, it becomes inevitable for all dispatchers to have a wide-area view of the network for situational awareness and protection. This visualisation is accomplished with the aid of protection (p) type micro-phasor measurement unit (PMU) installed at the bus of the respective distributed generation (DG). One of the pressing issues with DG's is the concern of inadvertent islanding that disrupts orderly reconnection besides posing hazards to utility workers. In view of this, this study proposes a real-time inadvertent islanding detection by PMU. The voltage and current phasors obtained from these PMUs by discrete Fourier transform are further processed by Fortescue transform to compute the angle of sequence components. The absolute angle difference between positive and zero components is used to initiate signal for accomplishing intelligent islanding under islanded condition. The simulation results prove the method to be robust, computationally efficient, non-detection zone free and feasible. Most significantly, as measuring equipment and relay are already present in p type PMU, therefore unlike other detection methods, no extra arrangements are required in this method making it economically viable and easy to implement.