Practical Issues of Processing Synchrophasor Measurement Data in the Analysis of Low-Frequency Oscillations in Power System

One of the important problems in ensuring the quality of power systems operation is the analysis of their oscillatory stability [1–3]. The poorly damped low-frequency oscillations (LFO) negatively affecting the reliability of the system are particularly interesting [1, 2, 4]. One of the main reasons for their occurrence is a significant power imbalance, and one of the factors of their continuation and development is the incorrect work of the regulators of the excitation system of electric generators [1, 2]. The poor damping of these oscillations leads to negative consequences, for example, the degradation of power quality, undue stress on equipment, system separation, blackouts, and others. The mentioned oscillations are observed in the low-frequency part of the spectrum (to 4 Hz) of the measured quantities (power, frequency) [5, 6]. The corresponding components of the measurement signals are called low-frequency modes. The example of measured signal and two low-frequency modes are shown in Fig. 1.