HIERARCHICAL COMMUNICATIONS
INFRASTRUCTURE IN SMART GRID
Xiaoxia Zhang
x79zhang@bbcr.uwaterloo.ca
OUTLINE
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Cognitive Radio Based Hierarchical
Communications Infrastructure for Smart Grid
Hierarchical communciation structure
Challenges on the design of communication architecture
Cognitive radio based architecture
Reliable Overlay Topology Design for the Smart
Microgrid Network
Microgrid
Smart microgrid
Overlay topology design for smart microgrid networks
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Cognitive Radio Based Hierarchical
Communications Infrastructure for Smart Grid
HIERARCHICAL STRUCTURE
HIERARCHICAL STRUCTURE
Home area network (HAN)
- communicate with various smart devices to
provide energy efficiency management and
demand response
 Neighborhood area network (NAN)
- connect multiple HANs to local access point
 Wide area network (WAN)
- provide communication links between NANs and
the utility systems to transfer information
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CHALLENGES ON THE DESIGN OF
COMMUNICATION ARCHITECTURE
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Tremendous data amount
- explosive growth of data gathered by smart meters and sensors
- utilities handle 10,780 Tbytes in 2010, 75,200 Tbytes in 2015
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Energy sources
- balance utility source and renewable energy sources
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Highly varying traffic
- peak hour requires high data rate and more reliable services
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Interoperability
- ensure operation among generation, transmission, distribution and
user networks
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Quality of service
- meter data needs higher priority and QoS, while price data needs
normal priority and QoS
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Security
- computer networks for controlling and monitoring, exposed to attacks
COGNITIVE RADIO BASED ARCHITECTURE
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Motivations:
Increasingly intensive radio systems in HAN.
CR improves spectrum utilization and
communication capacity to deal with large
amount of data.
CR devices could manage context awareness to
enable the realization of the heterogeneous
network.
COGNITIVE RADIO BASED ARCHITECTURE
COGNITIVE RADIO BASED HAN
HGW: cognitive home gateway used to transmit
data and manage spectrum band.
 Two components: spectrum access controller and
power coordinator.
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COGNITIVE RADIO BASED NAN
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NGW allocates spectrum bands to HGWs.
Guard channel strategy: some reserved channels for
handoff for both PUs and SUs to guarantee QoS.
Pd: dropping prob. Pb: blocking prob.
NG: guard channal NC: common channel
COGNITIVE RADIO BASED WAN/NAN
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A WAN has K NANs.
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Reliable Overlay Topology Design for the Smart
Microgrid Network
MICROGRID
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Small-scale, self-contained medium/low power system.
Distributed generators (DG), controllable loads, small-scale
combined heat and power units (CHP) and distributed
storage (DS).
Two operation modes: grid-conected and islanded.
SMART MICROGRID
Less transmission loss and less cable loss
 Reduce carbon emission
 Fault isolation in case of a failure or attack
 Ease of DG handling
 Energy trading among microgrids (future)
 SMGs can form a network SMGN to maximize
the utilization of renewable energy resources.
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OVERLAY TOPOLOGY DESIGN FOR SMGN
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Target
survivability (stay in working condition in case of
a failure)
utilization of the renewable resources more
effectively
Method
Form clusters in a SMGN
OVERLAY TOPOLOGY DESIGN FOR SMGN
Step1: Cluster SMGs.
 SMGN: G(t)={V,E(t)} where V is the set of SMG
and E(t) is set of logical links among SMGs.
|V|=N.
 Link between two SMGs (u,v)€E(t) means u and
v can share the storage bank.
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is binary, 1 if and only if SMG i and SMG j are
on the same cluster.
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Survivability for
Cluster r
OVERLAY TOPOLOGY DESIGN FOR SMGN
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Step2: Find a Hamiltonian cycle in each cluster.
SIMULATION RESULT
Questions and Discussion?
Thank you!
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