Hierarchical Cluster Classification of Half Cycle Measurements in Low Voltage Distribution Networks for Events Discrimination

Abstract

In   this   paper   the   Computational   Fluid   Dynamics   (CFD)   simulation of a wind turbine with a rotor diameter of 2.2 meters is  performed  using  the  Fluent  commercial  code.  Renewable  energies are only effective if implemented in a large scale basis. Given  this  fact,  this  CFD  study  is  part  of  the  effort  that  is  currently   being   made   at   the   University   of   Beira   Interior,   Portugal,  in  order  to  develop  a  family  of  complete  micro  wind  systems  suitable  for  partial  production  by  the  final  users.  The  target  objectives  of  the  project  are  to  provide  a  quality,  open  source,   small   wind   turbine   project   for   the   masses,   with   emphasis on low cost, reliability and ease construction. In a first phase  battery  charging  systems  are  being  developed,  to  be  followed later by grid connected ones. The micro turbines being developed  follow  the  mainstream  configuration  for  this  size  class, and so are of the horizontal axis type, have three blades, a tip   speed   ratio   of   6,   constant   pitch   and   a   passive   wind   orientation  system  with  side  furling.  The  generators  are  of  the  axial  flux  permanent  magnet  type.  The  blades  have  a  NACA  4415 wing section in all their span which is, at present, judged as  a  good  compromise  between  performance  and  structural  ruggedness given that it is a relatively thick profile. A 3D CAD model  of  the  rotor  was  modelled  with  the  Rhinoceros  3D  program.  In  order  to  support  the  physical  development  of  the  wind  turbine  CFD  simulations  were  performed.  In  this  work  results will be presented for turbulent flow computations around the  wind  turbine.  The  flow  was  computed  by  solving  the  Navier-Stokes   equations   with   kturbulence   model.   A   detailed  analysis  of  the  pressure  distribution  for  three  sections  along  the  blade  span  is  also  presented.  Load  distribution  and  boundary   layer   separation   is   studied.   Finally,   a   series   of   computations are performed in order to obtain the wind turbine torque  and  efficiency  signature  as  a  function  of  rotation.  The  obtained  results  will  be,  in  the  near  future,  compared  to  full-scale  field  tests.  These  will  be  carried  out  on  a  mobile  test  rig  currently  under  development  at  University  of  Beira  Interior,  Portugal.