Methods for Estimating Low-Frequency Oscillations in the Power System

The problem of identifying and damping low-frequency oscillations in the electrical operation mode is becoming particularly relevant for modern electric power systems containing renewable energy sources, flexible control devices based on power electronics, and featuring reduced margins of electrical network transmission capacity. Modern studies aimed at development of methods for assessing the parameters of low-frequency oscillations are reviewed and analyzed. It is shown that the existing methods are insufficiently efficient due to a significant delay and low adaptability. The article proposes a method for fast estimation of the parameters of low-frequency oscillations with a delay equal to a quarter of the oscillation cycle. The proposed method was tested on synthetic and physical signals. A digital model of a power system consisting of four synchronous generators was used as a source of synthetic data. Physical data are records of transients occurring in a real power system. To determine the accuracy of parameters characterizing low-frequency oscillations of the electrical mode, the article proposes a technique based on the analysis of the difference between the original signal and the signal reconstructed from the calculated parameters. As a result, the error values for the estimation of low-frequency oscillations were obtained, which confirm the accuracy and efficiency of the technique when analyzing both synthetic data and data from real power systems.