Sub-synchronous Oscillation Control Strategy Based on Impedance Identification for Wind Power Grid-connected System in Guyuan Area of China

Sub-synchronous oscillations caused by the interaction between large-scale wind power clusters and the power system seriously threaten the safety of power grid operation. This paper proposes an implementation framework and calculation method for sub-synchronous oscillation control based on system impedance identification. The system impedance is obtained by identifying the grid-side impedance and the impedance of wind farm branches. Based on the change of the real part of the system impedance, the effectiveness of the stability control system in cutting different wind farm branches is determined. Considering the influence of different wind farms on the system impedance, the control strategy for the sub-synchronous oscillation is formulated based on the principle of minimizing cut-off quantity. Aiming at the difficulty in identifying the grid-side impedance and the impedance of wind farm branches in the actual power grid, the methods for predicting the limit value of grid-side impedance and online measurement for the impedance of wind farm branches are proposed. Based on the PSCAD/EMTDC simulation platform, the actual power grid model in Guyuan area of China is constructed, which verifies the effectiveness of the proposed control strategy for sub-synchronous oscillation. © 2023 Automation of Electric Power Systems Press. All rights reserved.