A Comparison of Two Oscillation Analysis Techniques and Application to Protection Domain

Power system oscillations need careful analysis for a reliable and stable grid operation. In addition to the synchronous machine dynamics, grid proliferation of power electronic interfaced renewables has introduced new categories of oscillations. Oscillation monitoring has typically been considered as a control center functionality. However, with advancements in substation automation systems and introduction of centralized protection and control systems, substation-level oscillation analysis is feasible. This paper analyzes and compares two measurement-based oscillation analysis techniques, namely the matrix pencil method and the numerical algorithm for subspace state space system identification (N4SID). The study is based on simulated data and a few field records. The paper also presents potential applications substation-level oscillation analysis in supervising and supporting protection functions in modern substations.