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Coordination ofphase shifting transformers usingWide Area Measurements

Joachim BertschABB Switzerland Ltd.

Swiss Chapter of IEEE PES9 November 2006

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Agenda

The need for Wide Area Monitoring, Protection & Control

Wide Area Technology

Existing references of Wide Area technology

Coordination of phase shifting transformers

Benefits and conclusions

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Agenda

The need for Wide Area Monitoring, Protection & Control

Wide Area Technology

Existing references of Wide Area technology

Coordination of phase shifting transformers

Benefits and conclusions

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Today’s transmission systems…

...are more and more pushed towards their capacity limitsContinuous gradual growth in consumptionEnvironmental concerns restrict TS-extensionsIncrease in trading activities (cross border or inter-regional)Significant variation of power flow patternsHigher asset utilisation to increase profitability

Consequence: Increased occurrence of wide area disturbances

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4 November 2006

50.00 Hz

49.00 Hz

51.00 Hz

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Agenda

The need for Wide Area Monitoring, Protection & Control

Wide Area Technology

Existing references of Wide Area technology

Coordination of phase shifting transformers

Benefits and conclusions

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Wide Area Monitoring Systems

Window into the dynamic state of the power systemby use oftime synchronized measurementsfromdispersed sensors (Phasor Measurement Units, PMU)

WAMS

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Where does WAMS fit in?

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User of Wide Area Monitoring Systems

Increased system knowledgeSystem parameter identification

Planning

OperationEnhanced operation securityIncreased awareness

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WAMS applications

Monitoring and planning applicationsIncreased transfer capacity corridor/bottlenecks monitoringPower/frequency oscillation monitoringPost-disturbance analysisPower system model validation

Control room applicationsEarly warning of critical operating conditionsSecure system operation at contingencies and secure restoration

Closed loop applicationsCapacity increase by optimized load flow:Parameter adaptation forSVC and Phase Shifting Transformers (PST)

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Agenda

The need for Wide Area Monitoring, Protection & Control

Wide Area Technology

Existing references of Wide Area technology

Coordination of phase shifting transformers

Benefits and conclusions

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PSGuard / WAM-System Installations Worldwide

PSGuard WAM System in engineering phase

PSGuard WAM System delivered / in operation

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PSGuard / WAM-System Installations Worldwide

PSGuard WAM System in engineering phase

PSGuard WAM System delivered / in operation

ETRANSSwitzerland6 PMUs

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Etrans Switzerland – responsible for HV grid coordinationin Switzerland & South of Europe

Swiss gridwithin UCTE

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Switzerland – also the PMU countryETRANS monitors

Phase Angles

Line Temperature

Power Oscillations

BassecourtMettlen

Lavorgo Soazza

Sils

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PSGuard – Phase angle monitoring – Implementation in Switzerland

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PSGuard / WAM-System Installations Worldwide

PSGuard WAM System in engineering phase

PSGuard WAM System delivered / in operation

EGATThailand4 PMUs

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PSGuard project at EGAT, Thailand: Power oscillation monitoring

Bang Saphan

Surat Thani

Central-South power corridor

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PSGuard project at EGAT, Thailand: System design

System MonitoringCenter (Master)

SuratThani

BangSaphan

Basic Monitoring (BM) for all PMU measurements

230 kV

PMU 11 x 3 U2 x 3 I

Ethernet TCP/IP

Legend

230 kV line, MeasurementCommunication-link

Application (bold)POM

PowerOscillationMonitoring(POM)

PMU 31 x 3 U2 x 3 I

PMU 21 x 3 U2 x 3 I

PMU 41 x 3 U2 x 3 I

PowerOscillationMonitoring(POM)

+2 %0.8 Hz

0 %0.8 Hz

-2 %0.8 Hz

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PSGuard / WAM-System Installations Worldwide

PSGuard WAM System in engineering phase

PSGuard WAM System delivered / in operation

Austrian Power Grid(Verbund)3 PMUs

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PSGuard / Wide Area Monitoring at Austrian Power Grid

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System MonitoringCenter (Master)

System MonitoringCenter (Client 1)

WienSüdost

TernitzSchiene 1

Basic monitoring (BM) für alle PMU Messungen

Phase angle monitoring (PAM) für alle PMU Messungen

Linethermalmonitoring(LTM)

2 U3 I

220 kV

System MonitoringCenter (Client 2)

PMU 11 x 3 U2 x 3 I

PMU 2a2 x 3 U3 x 3 I

PM U 2b1 x 3 U1 x 3 I

Ethernet TCP/IP

Legendeee220 kV Leitung, Messung

Kommunikationsverbindung

TernitzSchiene 2

Phasenschieber -Transformator

(Optional)

(Optional)

PSGuard / Wide Area Monitoring at Austrian Power Grid 2005 /2006

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PSGuard / Wide Area Monitoring at Austrian Power Grid - Phase 1 Installation

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Agenda

The need for Wide Area Monitoring, Protection & Control

Wide Area Technology

Existing references of Wide Area technology

Coordination of phase shifting transformers

Benefits and conclusions

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The idea: Control of PST by Wide Area Control

Consequence of the electric utility industry deregulation and liberalization of electricity markets:

The amount of power exchanges between regions raises caused by trading activities.

Significant variation of power flows

.

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Observations

Increasing number ofphase shifting transformersin the European transmission grid

Need to control and coordinatephase shifting transformers

Availability ofWide Area Monitoring andControl Systems

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About phase shifting transformers

Phase shifting transformer (PST) create a phase shift between its primary (source) and secondary (load) terminals.

Purpose of this phase shift is the control of the power flow in a complex network.

PST can control power flow to ensure flow patterns determined by market conditions or thermal constraints

PST are typically controlled using local controllers

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About phase shifting transformers

A phase-shifting transformer (quadrature booster), is a specializedform of transformer

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About phase shifting transformers

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About phase shifting transformers

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Control of Phase Shifting Transformers (PST)

Continuous logging of system quantities for existing SCADAand off-line analysis

Improved State Estimation possibilities

On-line monitoring of power systemreaction during manual PST control

Optimal automatic control ofPST as a group

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Austrian grid

3 PST ordered and in installation

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Austrian Grid

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Step 2 Simulation: PST with local control and fault on corridor

Local PST control

Local PST control

Local PST control

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Step 2 Simulation: PST with local control and fault on corridor

Local PST control

Local PST control

Local PST control

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Step 2 Simulation: PST with local control and fault on corridor

When the fault occurs no corridor is overloaded

During the fault time the power is not equally redistributed between corridors

Margin available to transfer more poweralso when a fault occurs

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Step 3: Targets of Wide Area Control

Local control of phase shifting transformers is not optimal

Targets of Wide Area ControlPriority 1:Avoid overload on the three corridorsPriority 2Equally redistribute power flow also when a fault occursPriority 3Try to push more power through the corridorwithout violating the overload limit

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control

Load increasein all corridors

Step 4 Simulations: 3 PST and Wide Area Control, fault on corridor

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control

Step 4 Simulations: 3 PST and Wide Area Control, fault on corridor

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More transmission capacity

All three corridors are operated muchcloser to their limits

When the fault occurs in one corridorthe power flow is equally redistributed

The other two corridors „help“ the faulted one the total amount of power transferredis not decreased

Avoidance of harmful interactions ofmultiple PST devices (i.e. oscillations)

Fast and precisereaction of the system achieved byWide Area close loop Controlbased on phasor measurements

Closing the loop

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Additional benefits

Minimization of losses in the transmission grid,if phase shifting transformer used for power flow control in-between network levels

Better usage of all existing assets

Avoidance of critical situation by fast control actions at contingencies

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Agenda

The need for Wide Area Monitoring, Protection & Control

Wide Area Technology

Existing references of Wide Area technology

Coordination of phase shifting transformers

Benefits and conclusions

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Conclusion and summary

Risk management andcapacity improvementby coordination of phase shifting transformers usingWide Area Measurements

3 Consecutive steps:

PMU & WAMS installation

Integration into network control

Closed loop control

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Acknowledgements

Optional: Folienpräsentation zur Vermittlung der Praktikumsinhalte an die Studierenden

Herbert ErwenAustrian Power Grid, Vienna

Emanuelle DragoUniversity of Genoa

Mats LarssonABB Corporate Research, Dättwil