Transient analysis of grid-connected wind-driven PMSG, DFIG and SCIG at fixed and variable speeds

Abstract

This paper is aimed at presenting transient analysis of a grid-connected wind-driven permanent magnet synchronous generator (PMSG) at fixed and variable speeds by solving the system describing differential equations. For comparison purpose, wind-driven squirrel cage (SCIG) and doubly fed (DFIG) induction generators at fixed and variable speeds are studied using MATLAB/SIMULINK software package. Different from PMSG and DFIG the grid should feed the reactive losses of transmission lines and transformers at any value of short circuit ratio for SCIG. This increases the dynamic stability of DFIG and PMSG when compared with SCIG. Under three-phase-to-ground fault and single-phase-to-ground fault conditions, the time required to recover stability of PMSG wind farm is less than those  DFIG and SCIG wind farms for fixed and variable speeds indicating that PMSG is more stable than of DFIG and of SCIG wind farms.