Islanding Detection in Distributed Generations Using Negative Sequence Components

In this paper negative sequence components are used for islanding detection in distributed generation (DG) based system. In this approach, the negative sequence component of the voltage and current signals are analyzed through wavelet transform. The detailed coefficient d1 clearly identifies the event and thus detects the islanding condition. The change in energy and standard deviations of wavelet transform based voltage and current signals are also reported for islanding conditions and other disturbances called nonislanding ones. Also the negative sequence impedance is calculated at the target DG location. This negative sequence impedance effectively detects the islanding conditions. The proposed techniques are tested on islanding and possible non-islanding conditions such as normal operation, sudden load change and tripping of other DGs etc. And found to be more effective in islanding detection at target DG locations in the distribution network.