© 2016 Electric Power Research Institute, Inc. All rights reserved.
Mobolaji Bello
Power System Studies
August 29, 2016
Micro grid design:
Considerations & interconnection studies
2
© 2016 Electric Power Research Institute, Inc. All rights reserved.
Outline
3
© 2016 Electric Power Research Institute, Inc. All rights reserved.
Microgrid overview
• Are DERs able to regulate the voltage
and frequency within the island?
• Any issues with parallel grid operation?
• How is re-synchronization checked
against criteria such as out-of-phase,
large change in voltage?
Are existing telemetry / tele-control/
metering adequate?
• Are the fault contributions
from DERs sufficient to
allow satisfactory operation
of protection systems?
• Are existing protection
schemes adequate?
Plan, design, operate, control, monitor and optimize seamlessly
Microgrids
4
© 2016 Electric Power Research Institute, Inc. All rights reserved.
Microgrid Detailed Technical Design
Microgrid Project Objectives
Design Basis and Rationale
Performance Criteria
Site Descriptions
• Electrical & Thermal Needs
• Generation Assets
• Critical Load Needs
• Power Distribution Equip.
DER & Microgrid Controller
Codes & Standards
Control Needs
Communication Needs
5
© 2016 Electric Power Research Institute, Inc. All rights reserved.
DER Characterization
Renewables
▪ Solar Photovoltaics
▪ Solar Thermal
▪ Wind
Fossil Fuels Tech
▪ Boiler
▪ Fuel Cell
▪ Microturbine
▪ NG Genset
▪ Diesel (backup)
Energy Storage
▪ Electrical (Power, Energy)
▪ Thermal (Chiller, Refrig.)
Thermal Tech
▪ Heat Pump
▪ CHP
▪ HVACR
▪ Solar Thermal
Other
▪ Electric Vehicles
Electric Storage
• Aggregate capacity of all units (kwh)
• Maximum charge rate
(fraction of total capacity charge in one hour)
• Maximum discharge rate
(fraction of total capacity discharge per hour)
• Minimum state of charge
• Charge efficiency
• Discharge efficiency
• Decay/self-discharge (fraction of total capacity per
hour)
----------------------------------
• Fixed cost ($)
• Variable Cost ($/kw or $/kwh)
• Lifetime (years)
• O&M fixed costs ($/year)
Solar Photovoltaics
• # of modules
• Module rating (kW DC)
• Module Size (m2)
• Efficiency (%)
• Inverter size (kW AC)
• Total land area (m2)
----------------------------------
• Capital cost ($)
• Lifetime (years)
• O&M fixed costs ($/year)
• O&M variable costs ($/year/kW)
Microturbine
• Max Power (kW)
• Sprint capacity (% of power)
• # of sprint hours (hours)
• Fuel type
• Efficiency (ratio)
• CHP capable? (yes/no)
• Alpha (power to heat ratio)
• NOx emissions rate (kg/hr)
• Maximum annual operating hours (hours)
• Minimum loading (% of power)
----------------------------------
• Capital cost ($)
• Lifetime (years)
• O&M fixed costs ($/year)
• O&M variable costs ($/year/unit)
• NOx treatment costs ($/kg)
Electric Vehicles
• Multiple locations
• Min connect/disconnect SOC
• Max charge hours
• Battery size
• Efficiency
• Decay
• etc.
t
Connect
Disconnect
SOC
6
© 2016 Electric Power Research Institute, Inc. All rights reserved.
Data Collection Modeling Impact studies
Commissioning
& operation
Process
o Compliance with
protocols
o Model validation
o Submission of
models
o Real time ops &
monitoring
o Network models
•Load types
•DER types
•Operation
topology
o Protection info
o Scenarios
o Clear SOW
o Model validation
o Grid impact
studies
o Steady state
o Fault analysis
o Protection
coordination
o Stability studies
7
© 2016 Electric Power Research Institute, Inc. All rights reserved.
Design Analysis
voltage
time 
limits
unacceptable
overvoltage
Current
Impedance 
Relay
desensitization
Watts
Impedance 
Load Only
Load and PV
Energy
Time 
unserved energy
Energy exceeding
normal
Design Analysis
Approach
Load Analysis
Protection & Reliability
DER Sizing & Design
Distribution System Modeling,
Simulation & Optimization
Microgrid Controller
Architecture & Design
case by case
look needed
Location √
no impact
Location X
Potential risk
• Steady State load flow
• System Dynamic
• Harmonics
• Flicker
• Controls
• Operation seq.
• Fault Current
• Black Start
8
© 2016 Electric Power Research Institute, Inc. All rights reserved.
Key interests
9
© 2016 Electric Power Research Institute, Inc. All rights reserved.
Dynamic studies
Grid connected - all
DERs in parallel
Separation of the µ-
grid due to main
grid blackout
Black-starting
supplying crucial
loads
Islanded - with ALL
gens
Island - with
selected gens
Resynchronization
Plant(s)
Operation
mode
Use generic models for controllers and protection equipment
10
© 2016 Electric Power Research Institute, Inc. All rights reserved.
Use cases: Current projects
ConEd
• Highly meshed
• Huge fault levels
• Balanced
• 216V
• Various DER scenarios
SCE
• Radial
• Unbalanced
• 12kV
• 80 buses/nodes
• 39 lines, 12 loads
• 1 shunt capacitor
• Directional over current
• Analyze more options
• Early stages
• DER-CAM
• Deep dive 
11
© 2016 Electric Power Research Institute, Inc. All rights reserved.
Analytic tools
Steady state, fault
Steady state, fault, dynamic, protection, ALL
Protection
12
© 2016 Electric Power Research Institute, Inc. All rights reserved.
Detailed Design Analysis – Tools
Source: LBNL Paper LBNL-6708E
Need to apply a consistent modeling framework
Allow existing models to feed new analysis
PSCAD/EMTP-RV/MATLAB DesignBase
DIGSILENT
PSS/SINCAL
CYMDIST
SynerGEE
Transient Dynamic
Time-Series
Analysis/Slow
Dynamics
Time-Series
Analysis/SS
Steps
Steady State
All
OpenDSS/Grid Lab D/DEW
Microseconds Milliseconds Seconds Minutes Hours Days
A variety of MC capabilities requires a
variety of models to understand
• Performance
• Grid interaction
• System Protection Scheme Impact
13
© 2016 Electric Power Research Institute, Inc. All rights reserved.
Available Tools
Software Tool Affiliated Org. Tool Type
CYMDIST CYME International T&D Inc. Planning and simulation of distribution networks,
including load flow, short-circuit, and network
optimization analysis.
DER-CAM Lawrence Berkeley National
Laboratory (LBNL)
Techno-economic tool for microgrid design and
operation.
DesignBase Power Analytics Broad platform for electrical system design, simulation,
and optimization.
EMTP-RV POWERSYS Solutions Power system transients simulation, load flow,
harmonics.
EUROSTAG Tractebel Engineering GDF
Suez
Power system dynamics simulation; full range of
transient, mid- and long-term stability; steady-state
load flow computation.
GridLAB-D Pacific Northwest National
Laboratory (PNNL)
Distribution system simulation and analysis.
HOMER Homer Energy LLC, National
Renewable Energy
Laboratory (NREL)
Techno-economic tool for microgrid design and
operation.
OpenDSS Electric Power Research
Institute (EPRI)
Distribution system simulation and analysis.
PowerFactory DIgSILENT GmbH Power system analysis tool for load flow and
harmonics in transmission, distribution, and industrial
networks.
PSCAD Manitoba HVDC Research
Center
Power system transient simulation, load flow
simulation.
PSS/E Siemens Power Technologies
International (Siemens PTI)
Load flow, dynamic analysis, and harmonic analysis of
utility and industrial networks.
14
© 2016 Electric Power Research Institute, Inc. All rights reserved.
Simulation Tools - Comparison
Power
Flow,
balanced
Power Flow,
unbalanced
Short
Circuit
Relay
Coordination
Arc
Flash
Harmonic
Analysis
Transient
Analysis
Dynamic
Analysis
Quasi Steady-
State Analysis
EMTP-RV,
Simulink,
PSCAD
Aspen, Cape
DesignBase,
PowerFactory
PSLF, PSS/E
OpenDSS
GridLAB-D
Best choice
Can be done, but not preferred choice
Cannot be done
Tool
Study
15
© 2016 Electric Power Research Institute, Inc. All rights reserved.
Summary
“Microgrids” brings many technical needs: Good PSA tools available
No one-size fits all protection scheme works for all microgrids
Action plan
Continue testing various protection schemes
Level of dynamic studies details depends on so many
factors i.e. gen types, operation philosophy etc.
Best protection scheme depends on microgrid objective
• Network
• Objective
• Scenarios
• Modeling
 Grid requirements
 Controllability
 Monitoring
 Reliability
16
© 2016 Electric Power Research Institute, Inc. All rights reserved.
Together…Shaping the Future of Electricity
Jeff Smith
jsmith@epri.com
865.218.8069
Mobolaji Bello
mbello@epri.com
865.218.8005
Arindam Maitra
amaitra@epri.com
704.595.2646

4.4_Micro Grid Design_Bello_EPRI/SNL Microgrid

  • 1.
    © 2016 ElectricPower Research Institute, Inc. All rights reserved. Mobolaji Bello Power System Studies August 29, 2016 Micro grid design: Considerations & interconnection studies
  • 2.
    2 © 2016 ElectricPower Research Institute, Inc. All rights reserved. Outline
  • 3.
    3 © 2016 ElectricPower Research Institute, Inc. All rights reserved. Microgrid overview • Are DERs able to regulate the voltage and frequency within the island? • Any issues with parallel grid operation? • How is re-synchronization checked against criteria such as out-of-phase, large change in voltage? Are existing telemetry / tele-control/ metering adequate? • Are the fault contributions from DERs sufficient to allow satisfactory operation of protection systems? • Are existing protection schemes adequate? Plan, design, operate, control, monitor and optimize seamlessly Microgrids
  • 4.
    4 © 2016 ElectricPower Research Institute, Inc. All rights reserved. Microgrid Detailed Technical Design Microgrid Project Objectives Design Basis and Rationale Performance Criteria Site Descriptions • Electrical & Thermal Needs • Generation Assets • Critical Load Needs • Power Distribution Equip. DER & Microgrid Controller Codes & Standards Control Needs Communication Needs
  • 5.
    5 © 2016 ElectricPower Research Institute, Inc. All rights reserved. DER Characterization Renewables ▪ Solar Photovoltaics ▪ Solar Thermal ▪ Wind Fossil Fuels Tech ▪ Boiler ▪ Fuel Cell ▪ Microturbine ▪ NG Genset ▪ Diesel (backup) Energy Storage ▪ Electrical (Power, Energy) ▪ Thermal (Chiller, Refrig.) Thermal Tech ▪ Heat Pump ▪ CHP ▪ HVACR ▪ Solar Thermal Other ▪ Electric Vehicles Electric Storage • Aggregate capacity of all units (kwh) • Maximum charge rate (fraction of total capacity charge in one hour) • Maximum discharge rate (fraction of total capacity discharge per hour) • Minimum state of charge • Charge efficiency • Discharge efficiency • Decay/self-discharge (fraction of total capacity per hour) ---------------------------------- • Fixed cost ($) • Variable Cost ($/kw or $/kwh) • Lifetime (years) • O&M fixed costs ($/year) Solar Photovoltaics • # of modules • Module rating (kW DC) • Module Size (m2) • Efficiency (%) • Inverter size (kW AC) • Total land area (m2) ---------------------------------- • Capital cost ($) • Lifetime (years) • O&M fixed costs ($/year) • O&M variable costs ($/year/kW) Microturbine • Max Power (kW) • Sprint capacity (% of power) • # of sprint hours (hours) • Fuel type • Efficiency (ratio) • CHP capable? (yes/no) • Alpha (power to heat ratio) • NOx emissions rate (kg/hr) • Maximum annual operating hours (hours) • Minimum loading (% of power) ---------------------------------- • Capital cost ($) • Lifetime (years) • O&M fixed costs ($/year) • O&M variable costs ($/year/unit) • NOx treatment costs ($/kg) Electric Vehicles • Multiple locations • Min connect/disconnect SOC • Max charge hours • Battery size • Efficiency • Decay • etc. t Connect Disconnect SOC
  • 6.
    6 © 2016 ElectricPower Research Institute, Inc. All rights reserved. Data Collection Modeling Impact studies Commissioning & operation Process o Compliance with protocols o Model validation o Submission of models o Real time ops & monitoring o Network models •Load types •DER types •Operation topology o Protection info o Scenarios o Clear SOW o Model validation o Grid impact studies o Steady state o Fault analysis o Protection coordination o Stability studies
  • 7.
    7 © 2016 ElectricPower Research Institute, Inc. All rights reserved. Design Analysis voltage time  limits unacceptable overvoltage Current Impedance  Relay desensitization Watts Impedance  Load Only Load and PV Energy Time  unserved energy Energy exceeding normal Design Analysis Approach Load Analysis Protection & Reliability DER Sizing & Design Distribution System Modeling, Simulation & Optimization Microgrid Controller Architecture & Design case by case look needed Location √ no impact Location X Potential risk • Steady State load flow • System Dynamic • Harmonics • Flicker • Controls • Operation seq. • Fault Current • Black Start
  • 8.
    8 © 2016 ElectricPower Research Institute, Inc. All rights reserved. Key interests
  • 9.
    9 © 2016 ElectricPower Research Institute, Inc. All rights reserved. Dynamic studies Grid connected - all DERs in parallel Separation of the µ- grid due to main grid blackout Black-starting supplying crucial loads Islanded - with ALL gens Island - with selected gens Resynchronization Plant(s) Operation mode Use generic models for controllers and protection equipment
  • 10.
    10 © 2016 ElectricPower Research Institute, Inc. All rights reserved. Use cases: Current projects ConEd • Highly meshed • Huge fault levels • Balanced • 216V • Various DER scenarios SCE • Radial • Unbalanced • 12kV • 80 buses/nodes • 39 lines, 12 loads • 1 shunt capacitor • Directional over current • Analyze more options • Early stages • DER-CAM • Deep dive 
  • 11.
    11 © 2016 ElectricPower Research Institute, Inc. All rights reserved. Analytic tools Steady state, fault Steady state, fault, dynamic, protection, ALL Protection
  • 12.
    12 © 2016 ElectricPower Research Institute, Inc. All rights reserved. Detailed Design Analysis – Tools Source: LBNL Paper LBNL-6708E Need to apply a consistent modeling framework Allow existing models to feed new analysis PSCAD/EMTP-RV/MATLAB DesignBase DIGSILENT PSS/SINCAL CYMDIST SynerGEE Transient Dynamic Time-Series Analysis/Slow Dynamics Time-Series Analysis/SS Steps Steady State All OpenDSS/Grid Lab D/DEW Microseconds Milliseconds Seconds Minutes Hours Days A variety of MC capabilities requires a variety of models to understand • Performance • Grid interaction • System Protection Scheme Impact
  • 13.
    13 © 2016 ElectricPower Research Institute, Inc. All rights reserved. Available Tools Software Tool Affiliated Org. Tool Type CYMDIST CYME International T&D Inc. Planning and simulation of distribution networks, including load flow, short-circuit, and network optimization analysis. DER-CAM Lawrence Berkeley National Laboratory (LBNL) Techno-economic tool for microgrid design and operation. DesignBase Power Analytics Broad platform for electrical system design, simulation, and optimization. EMTP-RV POWERSYS Solutions Power system transients simulation, load flow, harmonics. EUROSTAG Tractebel Engineering GDF Suez Power system dynamics simulation; full range of transient, mid- and long-term stability; steady-state load flow computation. GridLAB-D Pacific Northwest National Laboratory (PNNL) Distribution system simulation and analysis. HOMER Homer Energy LLC, National Renewable Energy Laboratory (NREL) Techno-economic tool for microgrid design and operation. OpenDSS Electric Power Research Institute (EPRI) Distribution system simulation and analysis. PowerFactory DIgSILENT GmbH Power system analysis tool for load flow and harmonics in transmission, distribution, and industrial networks. PSCAD Manitoba HVDC Research Center Power system transient simulation, load flow simulation. PSS/E Siemens Power Technologies International (Siemens PTI) Load flow, dynamic analysis, and harmonic analysis of utility and industrial networks.
  • 14.
    14 © 2016 ElectricPower Research Institute, Inc. All rights reserved. Simulation Tools - Comparison Power Flow, balanced Power Flow, unbalanced Short Circuit Relay Coordination Arc Flash Harmonic Analysis Transient Analysis Dynamic Analysis Quasi Steady- State Analysis EMTP-RV, Simulink, PSCAD Aspen, Cape DesignBase, PowerFactory PSLF, PSS/E OpenDSS GridLAB-D Best choice Can be done, but not preferred choice Cannot be done Tool Study
  • 15.
    15 © 2016 ElectricPower Research Institute, Inc. All rights reserved. Summary “Microgrids” brings many technical needs: Good PSA tools available No one-size fits all protection scheme works for all microgrids Action plan Continue testing various protection schemes Level of dynamic studies details depends on so many factors i.e. gen types, operation philosophy etc. Best protection scheme depends on microgrid objective • Network • Objective • Scenarios • Modeling  Grid requirements  Controllability  Monitoring  Reliability
  • 16.
    16 © 2016 ElectricPower Research Institute, Inc. All rights reserved. Together…Shaping the Future of Electricity Jeff Smith jsmith@epri.com 865.218.8069 Mobolaji Bello mbello@epri.com 865.218.8005 Arindam Maitra amaitra@epri.com 704.595.2646

Editor's Notes

  • #8 Thermal capacity - Gx: value - add’l load, could be a limiting factor Energy analysis Transition: So how does this relate to transmission? On feeder level it doesn’t, you have to consider Dx in it’s entirety