Sustained Oscillation Analysis of VSC Considering High-Order Oscillation Components

Oscillations of grid-connected voltage source converter (VSC) usually reaches sustained state because of the limiters in controller. Describing function has been adopted to analyze the amplitude and frequency of the sustained oscillations, but high-order oscillation components caused by the limiter are ignored in previous literatures. This letter proposes an analysis method for sustained oscillations which considers high-order oscillation components. This method could obtain a more precise oscillation frequency and the amplitude of 1st, 2nd, and 3rd order components. The proposed method is verified by case studies and simulations in PSCAD/EMTDC.