Risk Assessment Method for Broadband Oscillation of Wind Farms Based on the Negative Resistance Effect

For the broadband oscillation problems caused by wind power grid-integration, a broadband oscillation risk assessment method is proposed from the view of negative-resistance (Neg-R) effect. Furthermore, the proposed method is verified to show its availability based on a practical wind farm (WF) with direct-drive wind power generators (WPGs). From case study, it shows that the port-impedance of WPGs does have a certain frequency band of Neg-R effect, which may cause some broadband oscillation problems. In addition, the frequency band of the Neg-R effect is greatly affected by the working conditions, thus the influence of the working conditions should be considered when evaluating the broadband oscillation risk of WF.