A Method of Discriminating Fault against Oscillation Based on Empirical Mode Decomposition

摘要

Power system oscillation is always causing wrong operation of distance protection. So it is necessary to discriminate between power fault and system oscillation. Because the fault voltage is a peaked wave with nonstationary component, it can be distinguished from oscillation voltage by the characteristics of amplitude and frequency variable. A new method based on empirical mode decomposition(EMD) was developed. EMD separated the phase voltage series to components with diu000berent time scale, say, intrinsic mode function( IMF), which eliminated the spurious harmonics and provided high-resolution time-frequency characteristics of system’s diu000berent work states. To demonstrate the performance of proposed scheme, various voltage signals of power system were identified. The results show that EMD has a significant potential in discriminating fault against oscillation disturbed by colored noises.