Estimation of Subsynchronous Oscillation Using a Sliding Window Iterative DFT Algorithm

Subsynchronous oscillation harms to the power system with the penetration of wind power. A new extraction method for energy grid-connected subsynchronous oscillation is proposed. A combination of sliding window and discrete Fourier Transform (DFT) algorithm to decompose the measured signals. Firstly, the fundamental frequency signals, and the sub-synchronous frequency signals are exacted in the oscillation interval, separately. Secondly, the frequency and amplitude of the subsynchronous component can be accurately obtained by the proposed method. The results shows the advantage in accuracy and computational burden. Thus, the proposed method has important practical value for monitoring the subsynchronous oscillation in the high penetration renewable energy power system.