Comparison Between Communication Infrastructures of Centralized and

Decentralized Wide Area Measurement Systems

Mohammad Shahraeini, Mohammad Hossein Javidi, and Mohammad Sadegh Ghazizadeh

Presented byYonghe Guo

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Outline

Background Introduction– Power Grid Control System

– Communication System (CI) Problem Formulation

– Optimum Communication Network

– LoM and NoR Experimental Result

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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

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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

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Control Strategies - decentralized control strategy

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Functions of Control Centers

Energy Management System– Online state estimation

– load flow

– optimal power flow

– load forecast

– economical dispatch

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Communication System – open system interconnection layer model

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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

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Communication System – Characteristics

Cost Bandwidth Propagation Delay Security Reliability

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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

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Measurement Placement – Centralized Strategy

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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.

Measurement Placement – Decentralized Strategy

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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.

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.

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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.

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NoR and LoM Applications - Latency Calculation

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NoR and LoM Applications - Reliability Calculation

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NoR and LoM Applications - Cost Calculation

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Experimental Setup

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

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Experimental result

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Experimental result - Distribution function of NoR and LoM

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Experimental result – Variance and Mean value of NoR and LoM

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Thanks!

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