Modular  Scalable  Transformer-­‐less  Unified  Power  Flow  Controller  

Fang  Z.  Peng  Michigan  State  University  

fzpeng@msu.edu  

1  

PresentaDon  Outline  

•  Today’s  Power  Grid:    Aging  infrastructure,  20th  century  technology  

•  21st  Century  (Smart)  Power  Grid:  More  reliable,  controllable/flexible,  and  opDmized,  but  how?  

•  Development  of  Modular  Scalable  Transformer-­‐less  UPFC  

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Power  system  is  complex,  massive,  inflexible  •  Electricity  system  (power  grid)  is  the  greatest  engineering  

achievements  of  the  past  century  (20th),  according  to  a  US  NAS/NAE  report.  

Source: Platts, 2005

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Transmission  Line  Network  Transmission  Lines  over  115  KV  

•  Complicated  meshed,  reliable  but  hard  to  control  

•  Due  to  lack  of  control  devices  (hardware),  the  network  has  to  be/has  been  over-­‐built  with  lots  of  excessive  capacity  and  more  new  lines  are  needed.    

•  Excessive  capacity  and  new  lines  do  not  contribute  to  total  loadbility  proporKonally.    SomeKmes,  switching  off  lines  would  be  beOer  off  (structure  or  topology  control)  

4  

Today’s  (20th  Century)  Power  Grids:  Aging  (Iron-­‐  and  Copper-­‐Based)  Infrastructure  

•  There  is  a  criDcal  need  to  modernize  the  way  electricity  is  generated  and  delivered  from  suppliers  and  consumers.  –  Central  power  plants,  big  turbine  generators  

–  Power  transmission  staDons  and  distribuDon  substaDons:  Big  transformers  

–  Lack  of  power  flow,  voltage,  and  frequency  control  devices  

–  Lack  of  energy  storage  systems  and  controls  

5  

Solid-­‐State  Electronics,  Comm./Networking,  and  InformaDon  Technology  can  make  it  more  intelligent,  

controllable,  flexible,  reliable,  and  efficient  

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Transform  Today’s  Power  Grid  to  Semiconductor-­‐Enabled  Power  System    -­‐-­‐21st  Century  Smart  Power  Grid  

•  High  Voltage  High  Power  electronics  –  Power  generaDon:  renewable  energy  with  power  electronics  grid  integraDon  –  FACTS  and  HVDC  (control  devices)  –  Energy  storage  

•  IT,  CommunicaDon  and  Networking  –  Smart  meters  and  smart  sensors  –  Two-­‐way  communicaDon  

•  Big  Data  and  OpDmizaDon  –  HolisDc  system  opDmizaDon  (millions  of  generators  and  buses)  –  Intelligent  power  generaDon,  rouDng,  and  demand  response  

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Future  Grid:  Smart  Elements  

•  Hardware  (or  control  devices)  to  control  voltage,  frequency,  and  power  flow  

•  So_ware  (Control  &  OpDmizaDon  algorithms/theory)  

•  Sensing,  communicaDons,  and  IT  

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More-semiconductor-enabled power systems

A  Uncompensated  Transmission-­‐Line’s  Loadability  Point A Point

B Physical length of the line

Real physical constraint

Lack-of-control-device constraint

Power System Analysis and Design Glover & Sarma

Ideal Power Flow Controller

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Benefits  of  Ideal  Power  Flow  Control  

•  Increase  loadability  to  thermal  limit  (typically  by  2-­‐6X  for  exisDng  and  new  lines)  

•  Minimize  operaDng/producDon  costs  •  Manage  congesDon,  regulate  voltage,  and  balance  power  

•  Provide  control  means  for  dynamic  opDmizaDon  

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Features of the UPFC: v Transformer-less; v Scalable CMI to reach

high-voltage levels; v No real power flowing

into the shunt and series CMIs.

Modular  Scalable  Transformer-­‐less  UPFC    

 

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Project  Goals  and  Technological  Advantages  

•  To  develop  and  demonstrate  a  transformer-­‐less  UPFC  •  To  demonstrate  UPFC  funcDons:  

ü  Voltage  regulaDon  ü  Line  impedance  compensaDon  ü  Phase  shi_ing  ü  Simultaneous  control  of  voltage,  impedance,  and  angle  ü  Dynamic  damping  of  power  oscilaDon  

•  Compact  and  light  weight  •  Low  cost,  modular  and  scalable  •  Easy  to  implement  n+1  redundancy  •  Fast  in  dynamic  response  to  increase  dynamic  raDng  of  transmission  line  assets/loadability  

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13.8-­‐kV/2-­‐MVA  UPFC  Prototype  

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Project  Summary  –Benefits/Impact  •  This  project,  if  successful,  will  have  enormous  technological  and  economic  impacts  on  controlling  the  rouKng  of  energy  over  the  exisKng  power.  

• Modular,  scalable  and  easy  installaKon  anywhere  in  the  exisKng  grid.  

• Maximizing/opKmizing  energy  transmission  over  the  exisKng  grids  to  minimize  the  need  for  new  transmission  lines.    

•  ResulKng  increase  in  the  transfer  capability  of  the  grid,  combined  with  the  controllability  and  speed  of  operaKon  of  the  devices,  will  enable  increased  penetraKon  of  renewables  and  demand  response  programs.  

•  Reducing  transmission  congesKon  and  increasing  dynamic  raKng  of  transmission  assets.  

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Case  Study  

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