Interpolated DFT-Based Identification of Sub-Synchronous Oscillation Parameters Using Synchrophasor Data

Abstract

In recent years, the proliferation of renewable generations significantly increases the severity and possibility of subsynchronous oscillations (SSO). These events can result in significant loss of generation and impose great threats to the system stability and equipment safefy. Accurate knowledge of SSO parameters (SSO frequency, magnitude and damping) is crucial for its effective mitigation. This paper presents a method to identify SSO parameters based on synchrophasors. The basic idea is to estimate SSO parameters by analyzing the spectral leakage information of SSO in synchrophasors. To achieve this, an interpolated discrete fourier transform is first adopted to accurately determine the frequency and damping of SSO. Afterwards, the magnitude of SSO can be calculated with the help of Hann-window. Case studies demonstrate that the proposed algorithm can accurately determine the SSO frequency, damping, and current magnitude. The performance has also proved to remain satisfactory under off-nominal, dynamic and noisy conditions. Moreover, comparative studies with the existing method show the superiority of the proposed method. This technique is thus a promising tool for online monitoring of SSO in actual power systems.