LowFrequency Oscillation Mode Source Identification with Wide-Area Measurement System

It can avoid low frequency oscillation in power grid if we can detect the oscillation mode with low damping ratio and identify the source in early stage. This paper presents the Frequency Domain Decomposition (FDD) method, which can extract the low frequency oscillation modes from measurements of Phasor Measurement Units (PMU) in normal operation condition. The damping ratio, modal frequency and the mode shape of poorly damped oscillatory modes can be directly determined from ambient PMU measurements. After the oscillation modes are identified by FCC method, the next step is to identify the source of oscillation modes and the Pearson correlation coefficient (PCC) method is proposed. Combined with FDD and PCC from status data in energy management system (EMS) and the oscillation mode results, we can identify the source of oscillation mode with high correlations. The case study shows that the combination of FDD and PCC is a very efficient way to process large volume of WAMS data and EMS data, identifying low frequency oscillation mode source, and provide possible way to take early actions preventing low frequency oscillation in power system.