Wavelet based Islanding Detection in a Three-Phase Grid Collaborative Inverter System using FPGA Platform

Interconnection of the distributed generation (DG) system with utility provides significant benefits. However, it requires a suitable technique to identify the islanding situation and execute tripping signal for disconnection of the DG system from remaining network. Islanding detection techniques are mainly classified as remote, active, passive and signal processing techniques. The passive methods have significant advantages like lower power quality degradation, lower cost etc. over the active method, however, it has limitations due to large Non-Detection Zone (NDZ) and threshold setting. Various signal processing techniques are adopted to overcome these limitations of the passive islanding technique. This paper presents a Discrete Wavelet Transform (DWT) based signal processing island detection technique for utility-interactive DG system. The DWT based island detection method provides time-frequency localization of the islanding situation and executes a signal to disconnect the DG system from the rest of the power system. The experimental feasibility of the proposed method is verified using Xilinx System Generator (XSG) via MATLAB/Simulink platform for demonstrating the competency of db8 Wavelet Transform (WT) under various disruptions.