Participation Factors Weak Robustness Analysis and Mitigation of Direct-Drive Wind Farms Connected to the Parallel-Compensated Grid

Abstract

Reactive power compensation requirement and large parasitic shunt-capacitor in offshore wind power generation systems form the parallel-compensated grid. However, the direct-drive wind farms connected to the parallel-compensated grid faces the risk of oscillations. This paper presents a unique phenomenon that the participation factors (PFs) of close oscillation modes in direct-drive wind farms connected to the parallel-compensated grid are sensitive to parameter perturbations. The phenomenon is defined as PFs weak robustness (PFWR) and its necessary conditions are revealed. To deepen the understanding of PFWR, the PFs transfer characteristics of close oscillation modes are analyzed under parameter perturbations. Then, the hazards of PFWR are discussed, and mitigation methods are proposed. PSCAD/EMTDC simulations of a multi-machine system are performed to verify the theoretical analysis.