Grid  Edge  Control  

Deepak  Divan,  IEEE  Fellow    President  &  CTO,  Co-­‐Founder  -­‐  Varentec  

 

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ISGT’14 Session: Utility Applications of Power Electronics and Renewable Power Integration

Background:  Electric  U<li<es  in  Transi<on  

Intermi@ent  +  Dispatchable    Genera<on  1600    GW  peak    (@20%  RPS)  

+ more T&D

on-­‐demand  loads  

§  10,000’s  of  generators  §  Visibility  to  dynamics  required  §  Dynamic  control  needed  at  periphery  

 §         100’s  of  generators  §         Poor  visibility  at  periphery  §         Control  is  central,  slow      

Dispatchable  Genera<on  1000    GW  peak  

on-­‐demand  loads  

2  

Limita<ons  of  Centralized  Primary  Side  Control  

•  Dynamic  voltage  drop  across  distribuEon  transformers  2  -­‐  8  volts  •  MulE-­‐point  control  required,  not  possible  with  central  command  &  control  •  Distributed  dynamic  Volt  VAR  Control  (VVC)  needed,  not  FACTS  •  Lack  of  grid  edge  control  limits  benefits  of  many  Smart  Grid  iniEaEves  

page  3  

ConvenEonal  Centralized  VVO  System  

SCADA

Primary  Distribution  Network-­‐  LTC,  Cap  Bank,  LVR,  EOL  sensor  etc

MeterHeadend

VVO Service  Transformer

Service  Transformer

Service  Transformer

Loss  of  control  at  grid  edge  

Feeder  EKG™  -­‐  Vola<lity  at  the  Grid  Edge  volta

ge  

NO    GRID  EDGE  CONTROL  

volta

ge  

lower  voltage  limit  -­‐  ANSI  

NO    GRID  EDGE  CONTROL  

Lack  of  Edge  Control  Limits  VVO/CVR  

 ENGO-­‐V:  Distributed  Grid  Control  

Distributed    Power  Control  

Wireless  Comms  

Data  Manager  Diagnos<cs  

Head-­‐end    Data  PlaYorm  

Autonomous  Distributed  Volt-­‐VAR  Control  

U  T  I  L  I  T  Y      O  P  S  

Voltage  Sensing  Event  Capture  

§  Decentralized  Volt  VAR  regulator  unit  §  Regula<on,  monitoring,  comms  all  in  one  box  §  Fast,  autonomous,  sub-­‐cycle  VAR  injec<on  §  System  analy<cs  &  diagnos<cs  

dnp3

6  

ΔV = 5 volts

WITH    GRID  EDGE  CONTROL  

Field  Data:  40  Units  on  a  Feeder  

ΔV of 5 volts enables 2X peak demand control

NO    GRID  EDGE  CONTROL  

Impact  of  PV  Dynamics  on  Grid  Voltage  

Source:  San  Diego  Gas  &  Electric  

•  Voltage  instability  at  PV  penetra<on  >  10-­‐15%  •  Dispatched  slow  Cap  Banks  cannot  solve  voltage  vola<lity  

8  

VAR  Support  Using  PV  Inverters  

•  Standard  Q/V  VAR  control  strategy  used  by  PV  inverters  worldwide  

•  Normal  ANSI  band  is  +/-­‐  5%  !  PV  inverters  don’t  support  grid  

•  Smart  inverters  working  autonomously  will  fight  each  other  

•  U<lity  VVO/CVR  objec<ves  directly  conflict  PV  grid  integra<on  9  

Grid  Edge  Control  Reduces  Impact  of  PV  Solar  on  the  Grid  

ENGO  ON  ENGO  OFF  

10  

Similar  Partly  Cloudy  Days  

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Value  Proposi<on   Benefits  

CVR/VVO  Energy  Savings   Fix  low  voltage  nodes,  allowing  improved  energy  conservaEon  

Peak  Load  ReducEon   On-­‐demand  peak  load  reducEon  with  no  customer  involvement  

Line  Loss  ReducEon  PF  Improvement  

Dispatch  VARs  to  improve  substaEon  power  factor  and  transmission  support  

PV  Dynamics  MiEgaEon   Dynamic  VARs  can  help  miEgate  primary  side  voltage  volaElity  due  to  distributed  PV  

Dynamic  VAR  InjecEon   Dynamic  voltage  support  for  momentaries  and  FIDVR  events  

Reduced  OperaEon  of  Primary  Assets  

Reduce  LTC/LVR/cap  bank  operaEon  for  longer  asset  life  

Improved  Reliability  and  Power  Quality  

Improved  voltage  compliance,  miEgaEon  of  low-­‐voltage  pockets  and  reliability/power  quality  improvements  

Feeder  AnalyEcs  Improved  Visibility  

Secondary  side  visibility  and  feeder  level  analyEcs  

Value  of  Grid  Edge  Control  

12  Grid  Edge  Control  -­‐  Summary  

•  New  paradigm:  distributed,  decentralized,  

dynamic  control  at  the  grid  edge  

•  Complements  exis<ng  centralized  

command  &  control    

•  Absorbs  dynamics  of  distributed  PV  

•  Allows  many  Smart  Grid  ini<a<ves  to  

deliver  on  promised  value  

•  Delivers  visibility  and  analy<cs  at  edge  

 

Edge of Network Grid Optimization