Stability improvement of a large-scale offshore wind farm using a superconducting magnetic energy-storage unit and a superconducting fault-current limiter

This paper presents stability-improvement results of a grid-connected large-scale offshore wind farm (OWF) based on superconducting synchronous generator (SCSG) and doubly-fed induction generator (DFIG) using a superconducting magnetic energy storage (SMES) unit and a superconducting fault current limiter (SFCL). The q-d axis equivalent-circuit model is derived to establish the complete system model under three-phase balance conditions. Steady-state operating points and system eigenvalues of the studied OWF under different wind speeds are examined. Transient simulations of the studied OWF subject to a three-phase short-circuit fault at the power grid are also carried out. It can be concluded from the simulation results that the proposed the SMES unit can offer better damping effects to achieve power flow control and stability improvement of the studied OWF. Transient stability of the studied OWF can also be further improved by the proposed SFCL.