CUSUM based Fault Detection of Stator Winding Short Circuits in Doubly-Fed Induction Generator based Wind Energy Conversion Systems

Abstract

This  paper  investigates  the  detection  of  short-circuit   faults   in   the   stator   winding   of   a   Wind   Energy Conversion  System  (WECS)  based  on  a Doubly-Fed  Induction Generator  (DFIG).  The  Cumulative  Sum  (CUSUM)  algorithm is  used  to  detect  the  change  in  the  stator  negative-sequence current  magnitude  which  is used  as  the  fault residual.  The  grid voltage  unbalance  is  considered  along  with  the  fault  position and  its  severity  to  evaluate  the  effect  on  the  residual.  The generator  is  modeled  using  the  winding-function  approach. Simulation  results  are  presented  for  a  15  kW  system  operated, under  a  power control strategy, at  rated conditions.  It  is shown that the fault-detection method is able to detect the fault rapidly and  is  not  influenced  by  the  grid  voltage  unbalance  within normal limits.