Hierarchical Communications Infrastructure in Smart Grid

1. Hierarchical Communications Infrastructure in Smart Grid Xiaoxia Zhang x79zhang@bbcr.uwaterloo.ca

2. Outline • 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 MicrogridNetwork • Microgrid • Smart microgrid • Overlay topology design for smart microgrid networks

3. Cognitive Radio Based Hierarchical Communications Infrastructure for Smart Grid

4. Hierarchical Structure

5. 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

6. Challenges on the design of communication architecture • 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 • Energy sources - balance utility source and renewable energy sources • Highly varying traffic - peak hour requires high data rate and more reliable services • Interoperability - ensure operation among generation, transmission, distribution and user networks • Quality of service - meter data needs higher priority and QoS, while price data needs normal priority and QoS • Security - computer networks for controlling and monitoring, exposed to attacks

7. Cognitive radio based architecture • 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.

8. Cognitive radio based architecture

9. Cognitive radio based HAN • HGW: cognitive home gateway used to transmit data and manage spectrum band. • Two components: spectrum access controller and power coordinator.

10. Cognitive radio based NAN • 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

11. Cognitive radio based WAN/NAN • A WAN has K NANs.

12. Reliable Overlay Topology Design for the Smart Microgrid Network

13. Microgrid • 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.

14. 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.

15. Overlay topology design for smgn • Target • survivability (stay in working condition in case of a failure) • utilization of the renewable resources more effectively • Method • Form clusters in a SMGN

16. 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. • is binary, 1 if and only if SMG i and SMG j are on the same cluster. Survivability for Cluster r

17. Overlay topology design for smgn • Step2: Find a Hamiltonian cycle in each cluster.

18. Simulation result

19. Questions and Discussion? Thank you!