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Presented by
MicrogridA new hub in energy
infrastructure
Mohammad Shahidehpour - Illinois Institute of Technology
Outline
• Smart Grid Technology – Electricity Infrastructure– What is Smart Grid
• Microgrids (IIT Perfect Power Project)– Components– Hierarchical Control, Islanding and Synchronization– Optimal Operation of Microgrid– Reliability Evaluation
• Perfect Power System – Robert W. Galvin Center at IIT
3
4
Restructuring
TRANSCO
GENCO
DISCO
Power System
GENCO GENCO
GENCO
GENCO
GENCO
Tie-Lines
Tie-Lines
DISCO
DISCO
C1 C2 C3 C4 C5 C6
Electricity Infrastructure
• Supply Adequacy and Economics: Applications of renewable energy, storagetechnologies for enhancing the security, coordination of renewable and storagesupplies, carbon footprints
• Transmission Expansion and Security: Expansion planning of transmission facilities,coordination of energy infrastructures, superconductors, HVDC, physical and cybersecurity, wide area measurements, PMUs
• Smart Grid: Energy efficiency, price response, peak load reduction, distributionautomation, new building technologies, smart metering, sensors, communication andcontrol techniques
What is Smart Grid? • Smart grid is a response to economic, security, and environmental
mandates placed on energy supply and delivery• Smart grid provides access points that can be identified, much like
computer devices, with an IP address on the internet• Smart grid uses the internet protocol to shuttle information back and
forth between the utility and customers• With two-way communications between consumers and suppliers, both
parties can get far more control over the grid consumption, and physicaland cyber security
Demand in MW
9
2
5
3
4
8
7
6
1
Time 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
18
4
10
6
8
16
14
12
2
Price [¢/KWh]February 24, 2000
Cost-based Price
Demand
Demand in a Vertically integrated Power Market
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Demand in MW
9
2
5
3
4
8
7
6
1
Time
18
4
10
6
8
16
14
12
2
Price [¢/KWh]
Customer Demand
Market-based Price
February 24, 2000
Response of a Demand to Price Signals
7
Introduction to Microgrids• Microgrid is a system with at least one distributed energy
resource (DER) and one demand which can be islandedfrom the main power distribution system (US DOE).
• Microgrids would address the emergence of a largenumber of DERs in distribution systems and to ensuresecure and optimal operations of potentially islandedpower grids.
• Microgrids generate, distribute, and regulate the flow ofelectricity to local customers, representing a modernsmall-scale power system with a high degree of flexibilityand efficiency in both supply and demand sectors.
Operation and Control of an Operational Microgrid for Service Restoration
• The short-term reliability algorithm devised at themicrogrid master controller would consider seamlessislanding and resynchronization and apply emergencydemand response and self-healing in case of majoroutages on either sides of the PCC.
• The economic operation would address the optimalgeneration scheduling of DER units in grid-connectedand island modes and would apply economic demandresponse for minimizing the operation cost.
9
Service Restoration Using Microgrids• Microgrid can assist distribution system service restoration
processes by providing one or more of the following services:
– Islanding from the grid for the local supply of microgridloads and reducing the supply provided by the utility grid.
– Coordinated reduction in microgrid loads by rendering anemergency demand response and curtailing non-criticalloads that would minimize the impact of outage on theleast number of customers.
– Increasing the microgrid generation for supplying localloads, and if possible, providing the microgrid surplusgeneration to the utility grid.
11
Distribution System Service Restoration Using Microgrids
• A distribution system may consists of a multi-microgrid system comprising severalmicrogrids each equipped with DER units connected through power electronicinterfaces and storage devices to provide power balances to a wider area duringblackouts.
12
Goals of the DOE RDSI Project
13
• 50% peak demand reduction
• 20% permanent demand reduction
• Demonstrate the value of Perfect Power
• Cost avoidance and savings in outage costs
• Deferral of planned substations
• New products and commercialization
• Replicable to larger cities
• Promotion of energy efficiency in cleaner cities
• Funded by the U.S. Department of Energy
• Located at Illinois Institute of Technology (IIT)
• Involves the entire campus
• Partners: IIT, Exelon, S&C, Schweitzer, Siemens, Schneider, Eaton, GE, Invenergy, Intelligent Generation, ZBB, Viryd, I-GO, Smart Signal, Catch The wind, Veriown, Keri
Perfect Power at Illinois Institute of Technology
“The perfect power system will ensure absolute and universal availability of energy in the quantity and quality necessary to meet every consumer’s needs. It is a system that never fails the consumer.” Bob Galvin
16
North
substation
South
substation4.16kV
12.47kV
4.16kV
PCC
Utility grid
Vis
ta1
E
Battery
Gas-turbine
Synchronous
Generators
Lo
op
1
Lo
op
3
Lo
op
7
PV
Lo
op
2
S
S
S
PV
SPV
PV
SEng.1
Vis
ta1
D
Wind
Vis
ta1
B
LS
Stuart
VanderCook
Machinery
CTA1
CTA2
Vis
ta1
A
Vista1C
High Reliability Distribution System (HRDS)• Implementation of microgrid loops is made possible by the use of automatic switches in
HRDS.• HRDS switches can sense the cable faults and isolate the faulted section with no impact on
other sections in a microgrid.
• No HRDS– Fault takes 30 cycles to clear.– The system is radial. Once the breaker opens, all the loads downstream will be
disconnected.• HRDS
– Fault takes 6 cycles to clear.– The system is loop. Once the breakers open, only the faulted cable is isolated.
17
HRDS Switches at IIT Microgrid
18
Vista Switch 1 Vista Switch 2
MV Breaker
(a)
(b)
Generator
Motor 1
Motor 1
Motor 2
Motor 2
Generator
0.6
0.65
0.7
0.75
0.8
0.85
0.9
0.95
1
1.05
0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0
Spe
ed (
p.u)
Time (Sec)
Without HRDS
With HRDS
Power Plant Control at IIT Microgrid
19
( )rated Sync.
Gen.Gas
Turbine
2nd
MT
Exciter
V
refP
refQ
Q
2ndV
ratedV
Tertiary
Control
P-ω
Primary
P-ω
Secondary
P
Q-V
Primary
Q-V
Secondary
Operation and Control of an Operational Microgrid for Service Restoration
• The three control levels in microgrids include:– Primary control which is based on droop characteristics of
DER units for sharing the microgrid load.
– Secondary control performs corrective action to mitigate frequency and voltage errors introduced by droop control.
– Tertiary control manages the flow between the microgrid and the utility grid and provides the optimal scheduling of DER units and demands in islanded and grid-connected operation of microgrid. Tertiary control would also provide ancillary services to the utility grid including voltage and frequency regulation and restoration services.
22
Hierarchical Control of Microgrid
• Primary & Secondary Control
24
2 3 4 6
60Hz
59.9Hz
f (Hz)
P (MW)
Droop1 (0.1Hz/MW)
Droop2 (0.05Hz/MW)
20 30 33 60
V0
4.00
V (kV)
Q (kVar)
Droop2
(1.5V/kVar)
Droop1
(0.7V/kVar)3.98
Primary controlSecondary
control
/f V
/P Q
rated
No change
in dispatch
A
B
C
Tertiary Control -- Microgrid Master Controller
25
Master
Controller
Solar (PV)Wind DAS
Thermal Generation
Generation Control
System
Building Control System
Sub-Building
Zigbee Control
System
Distribution System Control
Battery StorageCharging Station
Storage Control
System
Master Controller Formulation
• Master controller is responsible for the economic operation of themicrogrid based on signals received from HRDS switches.
• It monitors the status of HRDS switches using the SCADA system.
• It implements a three level hierarchical control (master, building,sub-building)
• It forecasts the real-time price of electricity and optimizes thehourly stochastic unit commitment/dispatch of local generation.
• Forecast errors of day-ahead load and wind speed and randomoutages of microgrid DG/distribution lines are considered.
• Monte Carlo representation of outages is applied and the LatinHypercube Sampling (LHS) technique is used to develop a largenumber of scenarios with equal probabilities.
26
Master Controller Formulation
27
, , , ,
, ,, , ,
( )
.( )
s s s sc i i t i t i t
t is
s D s d sst g t b t b t
t b
F P SU SD
Min pP VOLL P P
, , , , s s s s
i t g t k t D ti k
P P P P
, , , 1( ) s s si t i i t i tSU CS I I
, , 1 ,( ) s s si t i i t i tSD CD I I
min max, , , , , s s s s s
i i t i t i t i i t i tP UX I P P UX I
min max, , , s s s
g g t g t g g tP UX P P UX
Problem Formulation
28
,, , , ,,
, , , , ,
net s s sdc k t k c k tk t
s s sk t dc k t c k t
E P P
P P P
, , , , 1 s sdc k t c k tI I
min max, , , , , , , ,
min max, , , , , , , ,
s s sc k t c k c k t c k t c k
s s sdc k t dc k dc k t dc k t dc k
I P P I P
I P P I P
min max, , , , , , , , ,( ) ( ) s s s s
k dc k t c k t k t k dc k t c k tQ I I Q Q I I
,, , 1 ,
min max,
,0 ,
s s net sk t k t k t
sk k t k
k k NT
E E E
E E E
E E
Problem Formulation
29
,,, , , ,,
i g k dj j j j
inj ss s s d si t g t k t j tD t
i D g D k D d D
P P P P P
,,, , , ,,
i g k dj j j j
inj ss s s d si t g t k t j tD t
i D g D k D d D
Q Q Q Q Q
, ,, ,, ,, , ,
, , , 2 2 2 2, , , ,
t s t so j o jo j o jt s t s t s
o j o j o j
o j o j o j o j
r U x Uy g jb j
r x r x
Problem Formulation
30
, 2 ,
, , ,
, ,
, , , , , , , ,
( )
( )
[ sin( ) cos( )]
inj s s t s
j t j t j i
NBs s t s s s t s s s
j t o t j o j t o t j o j t o t
o j o
Q V B
V V G B
, , , ,
, , , , , , , , ,
( )
(2 1) ( 1) ( )NB
inj s s t s t s s s t s s s
j t j t j j j o j t o t j o j t o t
o j o
Q V B B V V G
, 2 ,
, , ,
, ,
, , , , , , , ,
( )
( )
[ cos( ) sin( )]
inj s s t s
j t j t j j
NBs s t s s s t s s s
j t o t j o j t o t j o j t o t
o j o
P V G
V V G B
, , , ,
, , , , , , , , ,
( )
(2 1) ( 1) ( )NB
inj s s t s t s s s t s s s
j t j t j j j o j t o t j o j t o t
o j o
P V G G V V B
Problem Formulation
31
, 2 , 2 , 2
, , ,( ) ( ) ( )t s t s t s
j o j o j oQL PL SL
, max
, ,
t s
j o j oSL SL
, 2 ,
, , ,
, ,
, , , , , , , ,
( )
[ cos( ) sin( )]
t s s t s
j o j t j j
s s t s s s t s s s
j t o t j o j t o t j o j t o t
PL V G
V V G B
, , , , , , ,
, , ,( ) ( )t s t s t s t s t s t s t s
j o j o j o j o j oPL G V V B
, 2 ,
, , ,
, ,
, , , , , , , ,
( )
[ sin( ) cos( )]
t s s t s
j o j t j j
s s t s s s t s s s
j t o t j o j t o t j o j t o t
QL V B
V V G B
, , , , , , ,
, , ,( ) ( )t s t s t s t s t s t s t s
j o j o o j j o j oQL B V V G
, , , ,
, , , ,
t s t s t s t s
j o j o j o j oSL PL QL
Optimal Operation of MicrogridPHASE V (Peak Load Reduction)
0
5
10
15
20
25
30
-1000
1000
3000
5000
7000
9000
11000
13000
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Pow
er
(kW
)
Time (Hour)
Utility Grid Supply
Total Demand
Utility Grid Supply With Building Controllers
Price of Electricity
Ele
ctr
icit
yP
rice (
cents
/kW
h)
Case No HRDS HRDS HRDS + Storage
Exp. SAIDI 1.22 0.18 0.04
Exp. SAIFI 3.29 0.59 0.37
Exp. CAIDI 1.73 0.36 0.04
Exp. CAIFI 2.69 0.68 0.29
Exp. Operation Cost 224,073 146,899 120,038
Exp. Energy not Supplied 1,216.21 251.07 175.10
LOLE 13.153 2.360 1.467
Mohammad Shahidehpour PhD
• Bodine Chair Professor / Director
• Galvin Center for Electricity InnovationIllinois Institute of Technology, LLC
33