These slides focus on preliminary discussions about wide area monitoring, protection and control in future smart grid. Later in the class i will show its application through simulation and case study results.

1. Wide area monitoring, protection and
control in future smart grid
Presented By:
Prof. (Dr.) Pravat Kumar Rout
Department of Electrical and Electronics Engineering
Siksha ‘O’ Anusandhan (Deemed to be University),
Bhubaneswar, Odisha, India
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2. Introduction
 The growth of electrical power systems is a challenge for Energy
Management Systems to ensure a safe and reliable operation.
 This situation originates the need for tools that help to visualize and control
electrical system variables using high speed communications channels
and accurate data, allowing the grid operator to estimate the state of the
system in real time through mathematical calculations.
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3. Continue…
 New technologies for monitoring electrical
systems implement Phasor Measurement Units,
as a main element of measurement, to
generate synchronized actions with sampling
times exceeding those currently obtained with
conventional SCADA systems.
 The process of conceptualization,
components and architecture are required for
the implementation of a WAMS data
acquisition system for Electric Power System.
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4. Challenges for future smart monitoring and
analysis systems
 Advanced power system measurement technologies have a key role to play in the
developments of Smart Grids. There are a number issues that make the
development of wide area monitoring systems an extremely difficult and
challenging task. Some of the prominent issues are:
 Sensor selectivity and intelligent data fusion.
Data paucity
 Integrated communications across the grid
 Advanced sensing and metering
Sensor placement
 Analysis of incomplete data
 Bandwidth requirements
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5. Wide Area Monitoring System (WAMS)
 Wide area monitoring systems (WAMS) are based on the new data
acquisition technology of phasor measurement and allow monitoring
transmission system conditions over large areas in view of detecting and
further counteracting grid instabilities.
 Current, voltage and frequency measurements are taken by Phasor
Measurement Units (PMUs) at selected locations in the power system and
stored in a data concentrator (PDC) every 100 milliseconds.
 The measured quantities include both magnitudes and phase angles, and
are time-synchronized via Global Positioning System (GPS) receivers with
an accuracy of one microsecond.
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 The phasors measured at the same instant provide snapshots of the status of the
monitored nodes.
 By comparing the snapshots with each other, not only the steady state, but also
the dynamic state of critical nodes in transmission and sub-transmission networks
can be observed.
 Thereby, a dynamic monitoring of critical nodes in power systems is achieved.
 This early warning system contributes to increase system reliability by avoiding the
spreading of large area disturbances, and optimizing the use of assets.
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7. Why Wide Area Monitoring Systems?
 Power management, as a tool for the security analysis to ensure reliability and
economical operation of the electrical system, are heavily dependent on the
accuracy of the data provided by the measuring equipment installed on the
system.
 In recent years, progress in system monitoring (power and control) has been
possible because of Wide Area Monitoring Systems (WAMS) that implement Phasor
Measurement Units (PMUs).
 When a PMU is installed on a node, it is possible to measure voltage and current
phasors in some or all adjacent areas to this node with high accuracy, enhancing
the efficiency of methods for fault detection and allowing to make decision to
keep system stability.
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Problems with SCADA based WAMS
•Data time skewed. Data scan rate upto10sec.
•Only magnitude measurements and phasors through state estimation-time extensive.

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10. Wide Area Monitoring Protection and Control (WAMPAC)
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11. Advance Functions of Energy Management
System
 Supervisory Control & Data Acquisition (SCADA) functions
 System Monitoring and Alarm Functions
 State Estimation
 On line Load Flow
 Economic Load Dispatch
 Optimal Power Flow ( including Optimal Reactive Power Dispatch)
 Security Monitoring and Control
 Automatic Generation Control
 Unit Commitment
 Load Forecasting
 Log Report Generation ( Periodic & Event logs), etc.
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A program scheduler may invoke various Application programs at fixed intervals.

12. Real Time information
 Real time data is a source of valuable information for automatic control as well as
for maintaining the stability of electrical power systems.
 It can also be used as a starting point for defining actions to recover the system
after a failure.
 The analysis and evaluation of different events previous to a blackout have shown
that a wide view of the network, as well as the availability of real time information
is a critical factor for the stability and reliability in the power supply.
 With high speed real-time measurements, appropriate protection and control
actions might be taken to ensure the reliability of the power system during the
occurrence any event.
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 Figure shows the relationship between the real time information and the decision-
making process:
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 Real time information acquisition and transmission are key for the optimization of
the system operation in Wide Area Monitoring Systems.
 In this regard, the communication architecture should be able to offer dynamic
information in real time and operational data for those who need it and when they
need it.
 The communication infrastructure should have the following characteristics:
 Bandwidth with capability to support the supervision of large area power
systems with high speed data transmission.
 Low latency to support local area and wide area for protection and real-time
control.
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 A WAMS process includes three different
interconnected sub-processes: data acquisition, data
transmitting and data processing.
 Measurement systems and communication systems
together with energy management systems perform
these sub-processes, respectively.
 In general, a WAMS acquires system data from
conventional and new data resources, transmits it
through communication system to the control
center(s) and processes it.
 After extracting appropriate information from system
data, decisions on operation of power system are
made.
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WAMS process in power systems

16. Wide Area Monitoring Systems
 Wide Area Monitoring Systems (WAMS) are essentially based on data acquisition
technology of phasor measurements, in order to monitor the transmission system
conditions over large areas, in view of detecting and further counteracting grid
instabilities.
 Current, voltage and frequency measurements are carried out by PMUs at selected
locations in the power grid (Generation, Transmission and Distribution systems) and
stored in a data concentrator every 100 milliseconds as shown in figure.
The measured variables include both magnitudes and phase angles, and are time-
synchronised via Global Positioning System (GPS) receivers with an accuracy of one
microsecond.
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17. Continue…
 The measured phasors provide instantaneous snapshots of the status of the
monitored nodes. By comparing the snapshots with each other, not only the
steady state, but also the dynamic state of critical nodes in Generation,
Transmission and Distribution Systems can be obtained.
 Thereby, a dynamic monitoring of critical nodes in power systems is
achieved.
 These early warnings in the system contributes to increase system reliability
by avoiding the spreading of large area disturbances, and optimizing the
use of assets.
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18. Continue…
The implementation of a WAMS contributes to get an electrical system with the
following characteristics:
 Security
 Power system stability
 Observability of networks
 Network controllability
 Blackout prevention
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19. Wide Area Monitoring Systems Components
 Wide Area Monitoring Systems collect
the information from the power
system, analyze the data and interpret
the result, giving “warnings” to the
system operator or initiating “defense
schemes” in order to prevent stability
problems.
 WAMS consist of the 3 major
components: Phasor Measurement
Unit (PMU), Phasor Data Concentrator
(PDC) and communication channel.
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Continue…

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23. Wide Area Monitoring Systems architecture
 Phasor Measurement Units are the input equipment for WAMS.
 PMUs measure voltage, current, frequency and frequency change rate as
prescribed standard and send to PDC based on the synchronizing time set
on GPS.
 Then, the Phasor Data Concentrator processes, monitors and analyses the
input data.
 Finally, the communication channel is responsible to transfer data from
PMUs to PDC.
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24. Continue…
The implementation of this architecture may have several objectives,
however, it can be stated that WAMS basically allow to:
 Validate simulation models: comparison of simulation data with
measured values of the PMUs.
 Identify system response with an analysis of the corresponding system
damping.
 Improve state estimation in the Energy Management System (EMS).
 Estimate the system stability index.
 Use as the guidelines for blackout restoration.
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25. Basic layout of wide area monitoring systems25

26. 26 Wide Area Monitoring Systems Architecture

27. 27 Wide Area Monitoring Systems Architecture

28. 28 Wide-area monitoring architecture

29. System Operator’s View29

30. Future Developments and Challenges
 Data exchange between Transmission System Operator (TSOs) is legally
formalized by bilateral agreements at the moment
 Exchange and utilize data more efficiently (technically, administrative)
 Develop a high-level concept for real time monitoring and an awareness
system based on WAMS technology
 WAMS is core system to capture dynamic characteristic of the system in
changing environment
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31. Major Utilization of WAMS
 The WAM technology may be utilised for the following.
 Preventing Blackouts
 Improved State Estimations
 Transmission Line Congestion Management
 Accurate calibration of Instrument Transformer
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32. Functions of WAMS
 Grid Model Validation
 Stability Analysis
 Real-Time Transient Stability Swings Prediction (Ex. Monitoring of inter-area
oscillations )
 Post Event Analysis,
 Fault Detection
 WAM data access and presentation
 Prevention of Cascading Outages
 Transmission line Relay Design
 State Estimation
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 Power Differential Protection
 Fault Location
 Voltage Stability Protection
 Fault Location
 Evaluating Multiple Reliability Indices
 Model validation
 Dynamic parameter estimation
 Evaluation of Security margin
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34. Wide Area Monitoring Protection and Control (WAMPAC)
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35. Conclusion
 The Wide Area Monitoring Systems collect, store, transmit and analyze
critical data from key access points in power system, spread over large
geographical areas, helping power system operators to continuously
analyze all variables in real time to ensure a reliable power supply to
customers.
 Improving WAMPAC in real time is required to achieve early warning
systems, system integrity protection scheme, detecting and analyzing
system stability, enabling faster system restoration, faster and more
accurate analysis of a vast number of data during transient events
validation and development of power system models.
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36. References
 Terzija, Vladimir, Gustavo Valverde, Deyu Cai, Pawel Regulski, Vahid
Madani, John Fitch, Srdjan Skok, Miroslav M. Begovic, and Arun Phadke.
"Wide-area monitoring, protection, and control of future electric power
networks." Proceedings of the IEEE 99, no. 1 (2010): 80-93.
 Shahraeini, M., Javidi, M. H., & Haq, Z. (2012). Wide area measurement
systems. Advanced topics in measurements, 303-322.
 Zima, Marek, Mats Larsson, Petr Korba, Christian Rehtanz, and Göran
Andersson. "Design aspects for wide-area monitoring and control
systems." Proceedings of the IEEE 93, no. 5 (2005): 980-996.
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37. Questions?
 Differentiate between SCADA and PMU based WAMS?
 What are the major challenges for implementation of WAMS
technology?
 Mention all the major applications of WAMS in future Smart Grid.
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