The document discusses Wide Area Measurement Systems (WAMS) which use Phasor Measurement Units (PMUs) to monitor the electric grid in real-time. WAMS provide improved situational awareness through synchronized high-speed measurements. They allow monitoring of system dynamics, identification of stability issues, and help design countermeasures. WAMS provide advantages like more frequent sampling, synchronized phasor data, improved visibility of the electrical system, and support for applications like oscillation monitoring, model validation, and event analysis. The Western Region Load Despatch Centre is working to develop WAMS applications including oscillation monitoring, dynamic state estimation, and wide area situational awareness.

1. WAMS
Analytical Approach
By :
Chandan Kumar
Engineer ,WRLDC

2. What is WAMS In WAMS Few Real Whats
WAMS WR Grid Application Time More on
Under Application the Way
Development
at WRLDC
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3. What is WAMS ?
• It’s a collective technology to
monitor power system dynamics in
real time, identify system stability
related weakness and helps to
design and implement
countermeasures . (IEEE)
• It is based on Phasor
measurement units (PMUs)
which can deliver precisely time
synchronized values of voltage
and current phasors and other
power system related quantities
like frequency, ROCOF, breaker
positions.
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4. Components of WAMS
•Phasor Measurement Unit (PMU)
•Phasor Data Concentrator(PDC)
•Global Positioning System (GPS for
Time Synchronization of the phasors)
• Communication channel( Preference
to optical fiber cable )
•Visualization and analysis tools
•Wide area situational awareness
system.
•Wide area protection and control
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5. Advantage of PMU
• More number of Samples(25-100 Phasors/sec)
1
• GPS Time Synchronized data to Control Centre from All Locations
2
• Finer View of the Electrical System
3
• Adaptive protection system can be developed
4
• Post Disturbance analysis with more accuracy which helps in planning.
5
• Many more …..
6
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6. Lets Have a closer view of SCADA and PMUs
Attribute SCADA PMUs
Measurement Analogue Digital
Resolution 2-4 samples per second Up to 100 samples per second
Observability Steady State Dynamic/Transient
Monitoring Local Wide- Area
Phasor Angle Measurement No Yes
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7. SCADA and PMU
Data from Present SCADA Millisecond Information with time
(Second Information , No time synchronization) synchronization
X-Ray vs. MRI of the GRID
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8. PMU+Visulization+Analysis+ GIS + Data
(Source : California ISO and OSIsoft LLC)
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9. Technology can Change what we See : Lets See How
Situational Awareness : Be preplanned rather than to wait
(Source : Space Time Insight)
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10. On our Path to Make the grid Smart and safely operate we have :
• PMU data
• RTU data
• GIS data
• Meteorological dept data
• Outage data
• Market data
So now We have BIG DATA
Need to Analyse Process VisualizeOperate
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11. Lets visit the world of PMU Advancement
More Visual Aids rather than Watching Number for Operators : A change
that is required with increase in the system Complexity and Big Data
Real-time Applications
•Wide-area situational awareness
•Frequency stability monitoring and trending
•Power oscillation monitoring
•Voltage monitoring and trending
•Alarming and setting system operating limits, event detection and
avoidance
•Resource integration
•Real time Dynamic State estimation
•Dynamic line ratings and congestion management
•Outage restoration
•Operations planning
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12. Contd..
Offline Application
• Base lining power system performance
• Event analysis
• Dynamic system model calibration and validation
• Power plant model validation
• Load characterization
• Special protection schemes and islanding
• Primary frequency (governing) response
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13. WAMS in Western Region
• 5 PMUs(1 Nos. Bhadrawati, 2 Nos. Jabalpur, 2Nos
Raipur)
• Different Vendors : GE,SEL,NI (More on way like
Hitachi, Qualitrol)
• PDC : OpenPDC, GE PDC (planning for iPDC and
OSIpi)
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14. Application under development @ WRLDC
Data Analysis Information Planning Decision Implementation
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15. •Oscillation Monitoring Systems
•Model validation.
•Dynamic Line Loadability.
•Voltage stability analysis.
•Dynamic & hierarchical State estimation
•Wide area situational awareness.
•Online stability assessment – Early warning.
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16. Application 1 : Oscillation in Grid
•In Similar manner electrical grid
has electrical inertia connected
by AC lines. So have modes of
Spring Mass System oscillation due to non-linearity of
It oscillates with frequency the system.
f = 1/2π (√(k/m))
Only one mode of frequency
•In similar manner system
connected with DC lines do
not oscillate with each other
Mass-Rod system
No oscillation
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17. What oscillation are observed in Electrical Grid ?
Small Signal
Stability
Local Global
(Intra Area) (Inter Area)
Local plant very low Higher
Inter-Unit
mode frequency frequency
(1.5-3.0 Hz)
(0.7 - 2.0 Hz) (0.1 to 0.3 Hz) (0.4 to 0.7 Hz)
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18. What Methods are used by WRLDC ?
Event Techniques Methods
Prony
Modal
Matrix
PMU Data Pencil
FDD
(Frequency
Domain
FFT
Decomposition)
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19. Why such oscillations poses threat to the system
• In normal power system state such LFO (Low frequency Oscillations ) are
well damped.
• However they get excited during any small disturbance in the system and
lead to oscillation in power system parameters like rotor velocity,
voltages, currents and power flows.
• Due to oscillations in parameters, protection of equipments may operate
leading to cascade tripping in power system.
• That’s why the observation of such modes is very essential in respect to
system reliability and security.
• Among these parameters the rotor velocities of the generators and the
power flows in the network are the most important.
• The rotor velocity variation causes strain to mechanical parts in the
power plant and should be limited.
• The power flow oscillations may amount to the entire rating of a power
line as if they are superimposed on the stationary line flow it will limit
the transfer capacity by requiring increased safety margins.
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20. Actions Required to Damp such Oscillations
• HVDC Damping Controller
• TCSC POD Tuning
• PSS Tuning of generators
• Proper Planning of transmission lines to Strengthen
the transmission network.
• Need to adapt Global PSS Tuning
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21. Application 2 : GRID INERTIA CALCULATION
•Incident :Talcher-Kolar Pole 2 Blocked on 19-05-12 16:14Hrs.
•System Frequency before operation of SPS(fo) : 50.21121 Hz
•Generation Loss(PL-PG) : 716.875 MW (SPS Operation)
•Generation of NEW grid after Tripping (PG): 81092.99
•df/dt observed from PMU =-0.02455 Hz/sec
H= 9.04 Seconds
(Nearly matched with the calculated Value)
Help in defining the response required from generation
and load during such disturbance
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22. Application 3 : Phase Angle Measurements and its importance
What Causes Power to Flow in the Grid
Load
DC power system - Power flows from a point of high voltage
to a point of low voltage.
Generation
AC power system - Power flows from a point of high voltage
angle to a point of low voltage angle. The higher the angle
the greater the power flow.
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23. What more we are working on
Collective effort from Operators-Academia-Industry to develop good PMU
tools for analysis
Cloud computing for analysis
Performance of PMUs from different vendors
Latency rate of PMUs depending on communication channel used
 Establishment of WAMS Lab
Voltage collapse analysis using PMUs
Looking for collaboration from all.
Please Find more detail on application in
“Synchrophasors Initiative in India”
By POSOCO.
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24. Thank You 
: chandan.wrldc@yahoo.com WRLDC ,POSOCO : 09869251460
15-Feb-13 Mob No