A novel out-of-step relay using wide area measurements

This paper proposes a new method for Out-of-Step (OOS) backup protection based on wide area measurements and discrete wavelet transform. The generators synchronized voltage and current phasors are transferred to Phasor Data Concentrator (PDC) center by means of Phasor Measurement Units (PMU). In PDC, the transmitted voltage and current signals are decomposed separately, at some levels, with a predefined Discrete Wavelet Transform (DWT). The retained energy in some decomposition levels of voltage and current signals is extracted and compared in an Energy V-I Plane, which reveals the generator instability. The algorithm is simulated on a Single-Machine-Infinite-Bus (SMIB) system, which obtained results show the efficiency and performance of the proposed algorithm as a backup protection for conventional OOS relays.