Wide Area Monitoring (WAMS)

Suphot JitlikhitHead in, Power System Analysis Section 1 Control & Protection Division Electricity Generating Authority of Thailand

December 8, 2010 EGAT, Thailand

Application of Phasor Measurement Units and Wide Area Monitoring System of EGAT’s Network

and Trend for Smart Grid

Smart Grid and Diagnostics

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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

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Wide Area Monitoring (WAMS) : use 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.

The acquired phasor data provides dynamic information on power systems, which helps operators to initiate corrective actions to enhance the power system reliability.

GPS satellite

PMU

PMUPMUPMU

WAMS & PMU

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Installation of PMUsat critical nodes in Power Systems.

GPS synchronized current and voltage phasor measurement.

Time resolution: < 10–6 s

Measurement quality: 0.1% of U and Iand Angle accuracy of < +/- 0.05%

Wide Area Monitoring (WAMS) : System Configuration

High precision data acquisition

WAMS & PMU

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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.

WAMS & PMU

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

WAMS & PMU

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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 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 & PMU

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

WAMS & PMU

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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..

Wide Area Monitoring (WAMS) : Project in 2010

WAMS & PMU

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

WAMS & PMU

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Wide Area Monitoring (WAMS) : SCADA vs. PMU Measurement

WAMS & PMU

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

WAMS & PMU

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WAMS Application Example: Phase Angle Monitoring

WAMS & PMU

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

PMU & WAMS14

Early warning

Emergency alarm

Normal Operation

WAMS & PMU

Benefit: Early warning against voltage collapses, Immediate stop of cascading effects, and Protection against uprising voltage instabilities.

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WAMS Application Example: Power Oscillation Monitoring

EGAT Wide Area Monitoring

EGAT

System Status: Normal, Warning and Alarm

WAMS & PMU

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

Real time monitoring Post-disturbance analysis Adaptive protection Power system restoration

WAMS & PMU

Goal & Benefits

Source: Dr. Luigi Vanfretti, KTH Sweden

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Benefit of Using PMU in EGAT &Trend Smart Grid: Real time monitoring

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To provide operators with real time knowledge of system conditions

Goal

Improve calculation for real time path flow and optimal dispatch Provide actual limits of the system instead of the conservative ones from offline calculations

Benefits of using PMU

WAMS & PMU

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Benefit of Using PMU in EGAT & Trend for Smart Grid: Post Disturbance Analysis

To reconstruct the sequence of events after disturbance has occurred

Goal

Benefits of using PMU

Easier to understand sequence of events when using synchronized data from PMU

WAMS & PMU

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Benefit of Using PMU in EGAT&Trend for Smart Grid: Adaptive Protection

Adapt protection to be appropriate with system condition

Goal

Benefits of using PMU

Improved backup protection Adaptive protection setting to avoid cascading outage

WAMS & PMU

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Benefit of Using PMU in EGAT&Trend for Smart Grid: Power System Restoration

Assist system operator during restoration with data from PMUGoal

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

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

WAMS & PMU

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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.

WAMS & PMU