1. Comparison Between Communication Infrastructures of Centralized and Decentralized Wide Area Measurement Systems Mohammad Shahraeini, Mohammad Hossein Javidi, and Mohammad Sadegh Ghazizadeh Presented by Yonghe Guo Page1

2. Outline  Background Introduction –Power Grid Control System –Communication System (CI)  Problem Formulation –Optimum Communication Network –LoM and NoR  Experimental Result Page2

3. Power System Control  utilizing the application of control theory and technology, optimization methodologies, and intelligent systems to improve the operation of power systems during normal and abnormal conditions Page3 Data are acquired from data resources Measured data are transmitted to control center through “measuring communication system” Decisions are made with this data and information Control commands are sent to controllable devices through “controlling communication system” Transmitted commands are run by controllable devices

4. Control Strategies - Centralized control strategy Page4

5. Control Strategies - decentralized control strategy Page5

6. Functions of Control Centers  Energy Management System –Online state estimation –load flow –optimal power flow –load forecast –economical dispatch Page6

7. Communication System – open system interconnection layer model Page7

8. Communication System – Classification  Dependent media: Part of power network elements –Power line communication –Broadband over power line –Optical power ground wire  Independent media: not rely on the power network –Open Access Media (wireless) –Internet –Telecommunication Network Page8

9. Communication System – Characteristics  Cost  Bandwidth  Propagation Delay  Security  Reliability Page9

10. Two Aims  use an optimization method to design the minimum length communication backbone network for any given power grid with determined measurements  proposed two new indices which can be used for comparing two different approaches of CIs Page10

11. Measurement Placement – Centralized Strategy Page11 J. Chen and A. Abur, “Placement of PMUs to enable bad data detection in state estimation,” IEEE Trans. Power Syst., vol. 21, pp. 1608–1615, Nov. 2006.

12. Measurement Placement – Decentralized Strategy Page12 L. Zhao and A. Abur, “Multiarea state estimation using synchronized phasor measurements,” IEEE Trans. Power Syst., vol. 20, pp. 611–617, May 2005. Decentralized ACCs are assumed to be at the chosen slack buses of different areas.

13. Optimal Communication Network  the links between data resources are considered to be weighted  the length of each transmission line is considered as the weight for that link  the optimal communication network is defined as the minimal spanning tree connecting all nodes. Page13

14. Two Indices  NoR (number of routers) is a number of nodes between considered node and control center and also known as “network hops”.  LoM (length of media) represents the length of media between considered node and control center. Page14

15. NoR and LoM Applications - Latency Calculation Page15

16. NoR and LoM Applications - Reliability Calculation Page16

17. NoR and LoM Applications - Cost Calculation Page17

18. Experimental Setup  IEEE 118 Testcase  Apply Genetic Algorithm to find the MST  Use Breadth First Search to estimate NoR and LoM Page18

19. Experimental result Page19

20. Experimental result - Distribution function of NoR and LoM Page20

21. Experimental result – Variance and Mean value of NoR and LoM Page21

22. Thanks! Page22