“…Since Wind Energy Conversion Systems constitute the largest variable renewable energy sources with large scale integration, several studies have been carried out to investigate voltage stability of power grids with high penetration of wind energy systems [ 1 , 9 , 23 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 ]. Three of the most-commonly investigated WECS are the Permanent Magnet Synchronous Generator (PMSG) based WECS, Doubly-Fed Induction Generator (DFIG) and Squirrel-Cage Induction Generator (SCIG).…”