Thinking... Why isn’t it practical to examine a whole population?
Thinking About the Whole Grid: Grid Architecture
Transcript of Thinking About the Whole Grid: Grid Architecture
1
Thinking About the Whole Grid:
Grid Architecture
2
The Word “Architecture” Is Used Many Ways• House or building layouts• Master plans• Organization models
device like an integrated circuit chip company internal arrangement
• Block diagrams• High level (“logical”) design views of IT systems• System designs or implementations• Other abstractions like layer models
We need to be clear on what we mean by grid architecture.
3
Purposes:o Identify legacy constraints
o Remove barriers and refine essential limits
o Help manage complexity (and therefore risk)
o Support early stage modernization processes
o Identify gaps in structure, technology
o Assist communication among stakeholders
o Define platforms
o Inform interfaces and interoperability
Architecture An abstract depiction of a system,
consisting of black box components, structure, and externally visible properties
System Architecture
Architecture is not design.
4
Elements of System Architecture: Components
• Abstract components– The individual parts, viewed as
“black boxes”
– Example: storage battery• At this level we do not specify
how the battery works• Care about externally visible
characteristics like storage capacity, max power rating
– But thoroughly grounded in reality • no “magic” boxes, miracles, or
anti-gravitySource: Sidney Harris
5
Elements of System Architecture: Structure• Abstract components
– The individual parts, viewed as “black boxes”– But thoroughly grounded in reality (no “magic” boxes)
• Structures– The overall shape of the system and how components
interact– Any complex system has multiple structures, requiring
multiple views– No real architecture can be represented in a single diagram
6
System Complexity and Electric Grids
MediumComplexity
HighComplexity
Power systems are off the chart…
LowComplexity
Complexity is the hidden bear in the room when dealing with grid futures.
7
Why is the Grid Ultra-Large-Scale Complex?• The grid is
comprised of many already complex structures
• These structures are interconnected and interact in complex ways
• This results in an explosion of complexity.
8
Purposes:o Identify legacy constraints
o Remove barriers and refine essential limits
o Help manage complexity (and therefore risk)
o Support early stage modernization processes
o Identify gaps in structure, technology
o Assist communication among stakeholders
o Define platforms
o Inform interfaces and interoperability
Architecture An abstract depiction of a system,
consisting of black box components, structure, and externally visible properties
System ArchitectureGrid Architecture is the application of system architecture, network theory, and control theory to the electric power grid.
A grid architecture is the highest level description of the complete grid, and is a key tool to help understand and define the many complex interactions that exist in present and future grids.
9
Grid Architecture Focuses on Structure• Because we have inherited
much legacy grid structure, new capabilities and improved characteristics can require understanding of existing grid structure and potential changes to grid structure
• Determining minimal changes to relieve structural constraints is a key grid architecture problem • Get the structure right and all the pieces fit into place
neatly, all the downstream decisions are simplified, and investments are future-proofed
• Get the structure wrong and integration is costly and inefficient, investments are stranded, and benefits realization is limited
10
Values of Good Structure
• Good structure has well-understood properties that can be relied upon for grid design.
• Proper structure creates intrinsic grid characteristics that bolster resilience, capability, and affordability and help safeguard investments by limiting change effects.
• Well-planned grid structure simplifies downstream decisions and frees up architects and engineers working on individual components or systems to employ creativity with assurance that unintended consequences will not crop up to hamper or even invalidate their work.
11
Grid Architecture Methods• Clarity of definitions• Focus on structure• Uses foundational
principles• Driven by:
• User requirements• Emerging trends• Public policy/regulation
• Agnostic to:• Products and services• Business models• Hype cycles
• Reference architectures are instructive, not prescriptive
Manage ComplexityProduce Insight
Customer expectations
Emerging trends
Policy/Reg
Grid Present State
Systemic Issues
Arch Principles
Arch Dev
Architecture
Objectives
12
You Do Not Have to be an Architect to Use the Results of Grid Architecture
Grid Architecture supports a wide range of stakeholders, including:
Consumers and
Prosumers
Public Policy Makers,
Regulators
UtilityExecutives
Engineers and Grid
Operators
Grid ProductVendors Researchers
User Domain Provider Domain
Applying Grid Architecture
14
A Few Core Grid Architecture Principles
• Understanding structure and structural context• Structure Problems: Bypass Hidden coupling Gapping
• Modularity and Decoupling• Layering and Platforms• Buffering• Layered Decomposition
14
Structure Models: ERCOT
15
FederalLegislature
PUCT
Federal Hydro Generators
Public Hydro Generators
C&I CustomersResidential Customers
Independent Market Monitor
Power Market Administration
FERC
Texas Legislature
Entity Class
only 1zero or 1zero or more1 or more
KeyAggregators
A Brelation>
A acts on or for B
A B<relation
B acts on or for A
A B<relation>
bilateral relation
Energy and services
Control and coordination
State regulation
Federal regulation
Retail
Market interaction
Reliability coordination
NERC Texas RE
Neighboring Grids with DC
Ties
Bulk Power Marketers, Arbitragers
Merchant Generators
Distributed Generator
Other Transmission
Operators
Competitive Retail Electric
Provider
Distribution Provider
Transmission Service Provider
Balancing Authority
Reliability Coordinator
Transmission Operator
Wholesale Market
Operator
ERCOT
1. ERCOT fulfills other NERC functions not indicated in this diagram2. Potomac Economics is the current Independent Market Monitor.3. The dotted lines connecting entities in the retail layer show the relations in the absence of any REP4. TSP approves or denies transmission service requests from purchasing-selling entities, generator owners and load-serving entities (not shown in diagram)5. All market participants are monitored by Potomac Economics, and they have to be notified any changes in ownership and structure (not shown in diagram)6. Wholesale storage load is part of the merchant generators.
sets policy for >
< approval and oversight
< regulates
regu
late
s ope
ratio
n >
licen
ses &
insp
ects
>
delegates development & enforcement of standards >
oversight on compliance >
enacts policy through >
< de
lega
tes
relia
bilit
y m
onito
ring
to
oversees and regulates >
< reports on competitive performance &
operational efficiency
monitors market participants & rules >
< provides reports on reliability to
compliance enforcement >
< re
gula
tes
oversight on compliance >
mon
itors
& d
irect
s >
operates distribution facilities & provides services for >
< sells retail electricity to
< co
ordi
nate
s op
erat
ions
>
< ba
lanc
ing
& co
ntro
l
reliability alerts >
< re
gula
tes
< coordinates operations
oversight on compliance >
< interchange power >
regulates >
< DC interchange services
<coordinate power exchange>
< DC interchange services
Resource Entity
Retail Market Operator
provides customer switch information >
prov
ides
met
er re
ads &
cu
stom
er c
onne
ctio
n >
Opt In Entity
serv
es c
usto
mer
s vi
a >
owns & operates >
Non Opt In Entity
< pr
ovid
es b
ulk
pow
er to
Qualified Scheduling
Entity< co
ordi
nate
tran
sfer
ca
pabi
litie
s
< co
ordi
nate
s op
erat
ions
< pr
ovid
e bu
lk p
ower
se
rvic
es to
< ba
lanc
ing
& co
ntro
l
balancing & control >
< directs system restoration
is a type of >
< balancing & control
repr
esen
ts >
< sells retail electricity to
Load Serving Entity
< re
pres
ents
repr
esen
ts >transacts with >
< represents
< re
pres
ents Bilateral
Market
can transact in >
Structural Models
16
ICE
bilateral markets(OTC)
System Operator(ISO or RTO)
operates >
LSEs(lncl bundled utils and
indep retailers)
bid to sell into >
< buy from
organizedwholesale markets
(FERC regulated)
operates >
bid to sell into >
Merchant & utility gen
DER/DER aggregators
sells into >
sell
into
>
Merchant & utility ancillary services
bid to sell into >
< bu
ys fr
om
brokers< transact > < buy through
resellers< bid to buy from
buy from >
TerminologyBA – Balancing AuthorityCFTC – Commodity Futures Trading CommissionDER – Distributed Energy ResourceICE – Intercontinental ExchangeIPP – Independent Power ProducerISO – Independent System OperatorLSE – Load Serving EntityNYMEX – New York Mercantile ExchangeOTC - Over the CounterPPA – Power Purchase AgreementRTO – Regional Transmission Organization
One; any particular
One and only one
Zero or more; optionally many
One or more; at least one
Cardinality Symbol Key
BA2
< operates
bid into >
bid
into
>Exchanges(CFTC regulated)
NYMEXoperates > < operates
hedg
e vi
a >
BA
< bid to buy from
Retail markets1
consumers
< bu
y vi
a
Auctions(capacity, ftr)
< buy from
< sell via
brokers
sell
thro
ugh
>
< transact >
PPAIPP owns > utility< buys electricity via
PPADGen Owner
owns > end users< buy electricity via
Special Case
hedg
e vi
a >
Notes1 Retail markets are not organized central markets. They are ad hoc bilateral arrangements.2 Some ISO/RTOs operate balance markets for neighboring BAs.
17
Sensor-Communications Network Layers:Reduce Dependency & Brittleness
Disjoint Sensor Sets
System 2
Application 1
Data Exchange via Interop Standards
System 3
Application 2
Application 3
System 1
SCADAData Coll Engine Virt Platform
CommunicationNetworks
Siloed ApplicationSystems
AMI DMS DERMS
Structure Transformation
Brittle & Expensive Resilient & Future-proofed
18
An Example Grid Architecture Method
19
Definition: The Grid Coordination Problem• Grid coordination is the systematic operational alignment of
utility and non-utility assets to provide electricity delivery• Coordination was not a well recognized issue for electric
distribution until fairly recently Some forms have been around a long time
o C&I DRo Bulk gen in deregulated industry segments
• The motivation for the present level of interest is the rise of three things: Distribution connected DG and DS Flexibly controllable loads Ubiquitous connectivity
Coordination is an issue because many of these resources are not owned by the utility and often may not be controlled directly.
20
Structural Problems to Avoid-1• Hidden Coupling
21
Structural Problems to Avoid-2
• Tier Bypassing• Coordination Gapping
Not So Simple in Real Situations
22
Federal Regulators
Federal Legislature
State regulatorState Legislature
WECC Peak RC
NPCC
BPA Power Marketing
Administration
Transmission (TO, TOP, TSP,
TP)
Balancing Authority (BA)
Federal Dams & Hydro
Generators
Public Hydro Generators Merchant IPPs Energy
Northwest
Other Balancing Authorities
Other Transmission
Providers
Public UtilitiesInvestor-Owned Utilities
Distribution Service Provider
Public Utility Governance
Direct Service Industries
C&I Customers Residential Customers
DER/DR Aggregators
Energy Imbalance
Market
CAISO
directs >
directs >
< directs
< ov
ersig
ht o
n co
mpl
ianc
e
regulates >
regu
late
s >
regulates >
crea
ted
>
sets priorities & recommends >
sets priorities & recommends >
coor
dina
tes
relia
bilit
y >
mar
kets
pow
er
from
>
< se
lls fi
rm &
seco
ndar
y no
nfirm
pow
er to
disp
atch
, con
trol
ge
nera
tion
><
coor
dina
te
pow
er fl
ow >
< di
spat
ch, c
ontr
ol
< in
terc
hang
e po
wer
>disp
atch
, con
trol
gen
erat
ion
>
< tr
ansp
ort b
ulk
pow
er to
(bila
tera
l co
ntra
cts)
enforces compliance >
< tr
ansp
ort b
ulk
pow
er
(bila
tera
l con
trac
ts)
< se
ll re
tail
elec
tric
ity
< di
spat
ch D
ER/D
R<
deliv
er p
ower
to
buy/
sell
reta
il el
ectr
icity
>
< di
spat
ch
DER/
DR
sets targets & reviews performance >
< re
lay
disp
atch
DE
R/DR
< se
ll re
tail
elec
tric
ity to
< op
erat
es
< tr
ansp
ort b
ulk
pow
er to
(B
ilate
ral c
ontr
acts
)
dispatch DER/DR >
< se
ll EI
M in
crem
enta
l pow
er
< se
lls p
ower
to
< se
ll in
dust
rial f
irm &
se
cond
ary
nonf
irm p
ower
to
sets policies and objectives >
Wholesale Power
Aggregators
Exchange
< po
wer
trad
ing
>
< po
wer
trad
ing
><
who
lesa
le
pow
er tr
adin
g >
Bonneville Power Administration (BPA)
Federal Columbia River Power
System
< se
ts p
riorit
ies &
co
nstr
aint
s
regulates >
sell EIM incremental power >
may
be
regi
ster
ed a
s EIM
en
tity
>
coor
dina
te
oper
atio
ns >
< co
ordi
nate
EIM
tran
sfer
s with
EIM
ent
ity B
A
• Want structure to be derived rigorously• Need a distributed form with knowable properties• Here we are not interested in a specific solution
but rather a class of solutions• We wish to extract essential structure by
understanding the problem class
Structural Basis for System Coordination
Mathematical Basis from Optimization Theory
Laminar CoordinationFramework
11
24
Network Utility Maximization viaLayering for Optimization Decomposition
• Well-known in optimization theory for solving problems with highly coupled constraints
• We will use the math to induce a coordination structure
Essential Laminar Coordination Structure
• Multi-layer structure
• “Vertical” chain of coordination nodes: scalable message flow
• Core repeating building block: coordination domain
• Scalable• Distributed
Mapping to the Grid
• Decomposition can be applied to as many levels as needed
• Known structural properties
• Accommodates multiple coordination approaches
• Boundary deference• Multi-level objectives
& constraint fusion– Local objectives &
constraints– Global coordination
• Proportional buildability
Adjusting Coordination Structure
TSO/BA
TransCo Merchant Gen
Cust Sites
Merchant DER
DSO
Microgrids
TransCo Merchant Gen
Cust Sites
DistCo
Microgrids
TSO/BA
Merchant DER
27
28
This Approach Leads to General Principles
• Scalable multi-layer form• Local selfish optimization inside global
coordination• Allows mixed coordination signal models:
– Allocations (control)– Prices (market-like methods)
• Proportional buildability
29
Grid Architecture Informs the TDC Coordination Problem in Useful Ways
• Scalability, granularity• Functional flexibility• Distribution platforms• Cyber security
• Roles and Responsibilities
• Grid observability • Distributed control• Coordination structure
30
Thank you
See Grid Architecture website at: https://gridarchitecture.pnnl.gov/