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

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

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

Control Strategies - Centralized control strategy Page4

Control Strategies - decentralized control strategy Page5

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

Communication System – open system interconnection layer model Page7

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

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

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

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

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 Decentralized ACCs are assumed to be at the chosen slack buses of different areas.

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

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

NoR and LoM Applications - Latency Calculation Page15

NoR and LoM Applications - Reliability Calculation Page16

NoR and LoM Applications - Cost Calculation Page17

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

Experimental result Page19

Experimental result - Distribution function of NoR and LoM Page20

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

Thanks! Page22