1. and Trend for Smart Grid
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, EGAT, Thailand

2. 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
WAMS & PMU

3. Wide Area Monitoring (WAMS) : use GPS Satellite
PMU
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.
The acquired phasor data provides dynamic information on power systems, which helps operators to initiate corrective actions to enhance the power system reliability.
WAMS & PMU

4. 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%
EGAT
Installation of PMUs at critical nodes in Power Systems.
WAMS & PMU

5. 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
WAMS & PMU

6. Central-South power corridor
Wide Area Monitoring (WAMS) : Power Oscillation Monitoring
Bang Saphan
Central-South power corridor
Surat Thani
WAMS & PMU

7. 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 time-synchronize 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.
WAMS & PMU

8. Wide Area Monitoring (WAMS) : Schematic Diagram
WAMS & PMU

9. 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..
WAMS & PMU

10. Wide Area Monitoring (WAMS) : Phasor vs. SCADA Comparison
WAMS & PMU

11. Wide Area Monitoring (WAMS) : SCADA vs. PMU Measurement
PMU is the higher time-resolution providing about power system dynamics in comparison with SCADA/EMS
WAMS & PMU

12. Wide Area Monitoring (WAMS) : Example for Real time Application
Phase Angle Monitoring
Voltage Stability Monitoring
Power Oscillation Monitoring
WAMS & PMU

13. 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.
WAMS & PMU

14. WAMS Application Example: Voltage Stability Monitoring
Early warning
Emergency alarm
Normal Operation
Benefit:
Early warning against voltage collapses, Immediate stop of cascading effects, and Protection against uprising voltage instabilities. 14
PMU & WAMS
WAMS & PMU

15. WAMS Application Example: Power Oscillation Monitoring
EGAT
EGAT
System Status:
Normal, Warning and Alarm
Wide Area Monitoring
WAMS Benefit:
Detection of oscillation, Assessment of power system damping, Increase power transfer at defined security, and Early warning to avoid power system collapse.
WAMS & PMU

16. 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
WAMS & PMU

17. 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 17
WAMS & PMU

18. Easier to understand sequence of events when using
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
WAMS & PMU

19. 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
WAMS & PMU

20. Goal Benefits of using PMU
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
WAMS & PMU

21. Benefit of Using PMU in EGAT&Trend for Smart Grid: Smart Transmission Grid
WAMS & PMU

22. EGAT has installed WAMS & PMU since 2005, for monitoring
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.
WAMS & PMU