Feature extraction for islanding detection using Wavelet Transform-based Multi-Resolution Analysis

This paper proposes a feature extraction method for islanding detection via Wavelet Transform (WT)-based Multi-Resolution Analysis (MRA). The WT-based MRA method is used to decompose the output voltage signals of distributed generation sources into different scales. A series of Wavelet Coefficients (WCs) is generated for each scale, which corresponds to a certain frequency bandwidth. The features for identifying islanding are extracted from the WCs by computing the ratio of the change of WCs before and after islanding. Simulation studies have been carried out for an inverter-based DG under different operating conditions using EMTP-RV. The simulation results show that the features obtained by the WT-based MRA method indicate the changes in high frequency harmonic components and can be potentially used for identifying islanding under different operating conditions.