Application of Phasor Measurement Units and Wide Area Monitoring

Report
Application of Phasor Measurement Units and
Wide Area Monitoring System of EGAT’s Network
and Trend for Smart Grid
Suphot Jitlikhit
Head in, Power System Analysis Section 1
Control & Protection Division
Electricity Generating Authority of Thailand
Smart Grid and Diagnostics
December 8, 2010
EGAT, Thailand
Contents
WAMS & PMU history in EGAT’s network
Phasor vs. SCADA Comparison
SCADA vs. PMU Measurement
Example for Real time Application
Benefits of using PMU in EGAT &Trend to Smart Grid
Conclusion
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Wide Area Monitoring (WAMS) : use GPS Satellite
GPS satellite
Wide Area Monitoring System use a
GPS satellite signal to time-synchronize
from phasor measurement units (PMUs)
at important nodes in the power system,
send real-time phasor (angle and
magnitude) data to a Control Centre.
PMU
PMU
PMU
PMU
The acquired phasor data provides
dynamic information on power systems,
which helps operators to initiate
corrective actions to enhance the power
system reliability.
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Wide Area Monitoring (WAMS) : System Configuration
GPS synchronized current
and voltage phasor measurement.
High precision data acquisition
Time resolution: < 10–6 s
Measurement quality: 0.1%
of U and I
and Angle accuracy
of < +/- 0.05%
Installation of PMUs
at critical nodes
in Power Systems.
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Wide Area Monitoring (WAMS) : Project in 2005
EGAT installation Wide Area Monitoring (WAMS)
Inter-area oscillation on the tie transmission line between the
Central system and the Southern system is one of the important
problems which lead to reduce stability and security of the
transmission system.
To prevent system from inter-area oscillation, Wide Area
Monitoring System (WAMS) was installed at the Central system and
the Southern system in 2005 to monitor the stability of this power
transmission network.
Bottleneck in transmission corridor:
Limit due to concerns about power oscillation , the origin, amplitude,
frequency, usual duration and damping of oscillation are not know
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Wide Area Monitoring (WAMS) : Power Oscillation Monitoring
Bang Saphan
Central-South power corridor
Surat Thani
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Wide Area Monitoring (WAMS) : PMU Installation
EGAT installation Wide Area Monitoring (WAMS)
Phasors Monitoring Units (PMUs) are installed at Bang Saphan and
Surathani Substation and use a GPS satellite signal to timesynchronize voltage and current readings as they are taken from
both substations.
Data can be streamed into a Control Center from far-flung points in
the grid, where it is evaluated to give grid operators a precise
picture of what is happening in their system, online. They can also
finally see what is happening beyond their own control area – an
advance over traditional monitoring and protection methods.
WAMS Benefit:
Detect of oscillation, Assessment of power system damping, Oscillation
Monitoring, Increase power transfer at defined security, and Early
warning to avoid power system collapse.
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Wide Area Monitoring (WAMS) : Schematic Diagram
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Wide Area Monitoring (WAMS) : Project in 2010
The project has upgraded from the existing of Digital Fault Recorder (DFR),
totally 6 sites and 14 PMUs installed.
This is as the pilot project to test the function of PMU on DFR platform.
Phasor Data Concentrator (PDC) and its software application has been
installed in the server and its display available at the operator console for
visualization.
This project has only used for monitoring purpose and observe the system in
broader scale..
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Wide Area Monitoring (WAMS) : Phasor vs. SCADA Comparison
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Wide Area Monitoring (WAMS) : SCADA vs. PMU Measurement
PMU is the higher time-resolution providing about power system
dynamics in comparison with SCADA/EMS
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Wide Area Monitoring (WAMS) : Example for Real time Application
Phase Angle Monitoring
Voltage Stability Monitoring
Power Oscillation Monitoring
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WAMS Application Example: Phase Angle Monitoring
Benefits:
Provide operator with real time information about voltage phase angle
deviation, Improve voltage control, improve system stability, security and
reliability , and operate safety carrying components closer to their limit.
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WAMS Application Example: Voltage Stability Monitoring
Normal Operation
Early warning
Emergency alarm
Benefit:
Early warning against voltage collapses, Immediate stop of cascading
effects, and Protection against uprising voltage instabilities.
PMU & WAMS
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WAMS Application Example: Power Oscillation Monitoring
EGAT
System Status:
Normal, Warning and Alarm
WAMS Benefit:
Detection of oscillation, Assessment of power system damping,
Increase power transfer at defined security, and Early warning to avoid
power system collapse.
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Benefit of Using PMU in EGAT & Trend for Smart Grid
Goal & Benefits
Real time monitoring
Post-disturbance analysis
Adaptive protection
Power system restoration
Source: Dr. Luigi Vanfretti, KTH Sweden
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Benefit of Using PMU in EGAT &Trend Smart Grid: Real time monitoring
Goal
 To provide operators with real
time knowledge of system
conditions
Benefits of using PMU
 Improve calculation for real
time path flow and optimal
dispatch
 Provide actual limits of the
system instead of the
conservative ones from
offline calculations
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Benefit of Using PMU in EGAT & Trend for Smart Grid: Post Disturbance
Analysis
Goal
 To reconstruct the sequence of events after disturbance has
occurred
Benefits of using PMU
 Easier to understand sequence of events when using
synchronized data from PMU
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Benefit of Using PMU in EGAT&Trend for Smart Grid: Adaptive Protection
Goal
 Adapt protection to be appropriate with system condition
Benefits of using PMU
 Improved backup protection
 Adaptive protection setting
to avoid cascading outage
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Benefit of Using PMU in EGAT&Trend for Smart Grid: Power System Restoration
Goal
 Assist system operator during restoration with data from PMU
Benefits of using PMU
 System operator have more confidence during restoration
 Reduce chance of recurrence of system outage
 Reduce time needed for a system restoration
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Benefit of Using PMU in EGAT&Trend for Smart Grid: Smart Transmission Grid
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Conclusion
 EGAT has installed WAMS & PMU since 2005, for monitoring
and resolution of power oscillation problem between Central and
Southern region. In 2010, more project has installed for visualization of
power system in broader scale.
 The capabilities of PMU for high precision, speed of response and
GPS time synchronization make PMU very appropriate for wide
area monitoring for protection and control.
 An Advanced early warning technology for power grids that helps
operators to ensure grid reliability by detecting and counteracting the
first signs of grid instability.
 Trend for the Smart Grid for the future.
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