Transcript Slide 1

Synchrophasor: Implementation,Testing &
Operational Experience
Uttam Mishra
Doble Engineering Company
©2012 Doble Engineering Company. All Rights Reserved
Presentation Topics
What is SynchroPhasor
Applications
Testing PMUs
Operational Experience
Conclusion
Phasor Measurement Unit
• Definition : Phasor
– Phasor is a vector which has magnitude and angle
– Corresponds to a sinusoidal waveform
θ
Phasor Measurement Unit
PMU typical configuration:
Pulse-Per-Second
GPS
antenna
Synchrophasors,
Frequency,
ROCOF
Data
streaming
GPS
receiver
Phasor
Measurement
Unit
Analog inputs
(voltages/currents)
A/D
conv.
Modem
Phasor and Synchro Phasor
• Time aligned Phasor : Synchro Phasor
• GPS satellites provides time stamp
• Time aligning helps to analyze system events
G
Zs
G
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θ
θ
Total Vector Error
Error
Expected
Phasor
Actual
Phasor
Ref
𝐓𝐕𝐄 % =
Length of Error Phasor
Length of expected Phasor
1% TVE ≈ .573 degrees (.01 * 360 / 2π)
≈ 26.5 μs (at 60 Hz)
Back up applications
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Power system stability
Two ended fault location algorithm
System diagnostics
Distributed Busbar protection
Load shedding
Wide area frequency monitoring
Power Swing Detection
• Protections settings done with known max and/or
min operating conditions of power system events
• Actual operation of power system events may not
be optimal for the setting of the protection
• PMU provides Phasors in real time
• Better decision can be made on load shedding
and system stability
• Real time Phasor value helps to fine tune State
estimation
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PMU : Power Swing
G
G
Zs
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θ
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θ
Calculate the angle difference due to disturbance
Apply equal area criteria
Make stability decision
Angle between will vary due to disturbance
Algorithm determines if diverging or settling
Blocking or tripping decision to be made
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Distance to Fault
• Single ended fault location algorithm inaccuracy
– Fault resistance, load flow & non homogenous system
• PMU enables double ended fault location
• PMU data from both end of the line provides very
accurate fault location
– Reclose decision can be made for mixed overhead and
cable transmission line
– Improved line patrolling :Better productivity & Reliability
– Fault location algorithm is based on positive sequence
system parameters
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CFE Network
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Automatic Generation Shedding
• CFE implemented AGSS scheme
• CFE has generation in southeast part of the
country while the large load is in the center
• If the angle between generation & load bus
exceeds certain value, generation can be tripped
• Loss of 400kV transmission capacity can cause
system out of step condition
– One line out of service : 70 Phase shift
– Both line out of service : 140 Phase shift
• CFE chose 100 to be setting for load shedding
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CFE Network
Remote Phasor
Local Phasor
Ʃ
Threshold
+
-
PU Cyc
Trip Selected
Generators
0
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Europe System Disturbance: November 4, 2006
Grid Islanding
8.9 GW deficit
49 Hz
10 GW surplus
51.4 Hz
0.8 GW deficit
49.7 Hz
Resynchronisation
• A number of uncoordinated unsuccessful attempts made
without knowledge of the overall UCTE situation
• Full resynchronisation after 38 minutes
Source: UCTE
UCTE root cause analysis
• Main points:
– (N-1) security rule, inadequate inter-TSO coordination
– Lack of situational awareness
– Other factors (wind farms, lack of coordination)
Improvements since 2006:
Situational awareness
• Web-based visibility of cross-border flows in
Europe,
• RAAS – real-time awareness and alarming
system
Coordinated (N-1) security analysis
• All national files are merged into one common CE
load flow file.
• each TSO downloads the complete system and
perform complete (n-1) calculation.
PMU Testing Concepts
Goal: under various conditions, make sure that the
reported each PMU data message matches the
expected values for each Phasor Vector, Frequency
Deviation and ROCOF.
PMU Testing Standard
• Defined in IEEE C37.118.1
• Specifies quantities to vary, ranges to vary over,
and required accuracies under different
conditions.
• Includes steady state tests, dynamic tests, and
transient tests
IEEE C37.118.1 Requirements
• Steady state tests
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Frequency
Voltage
Current
Phase (discrete or continuous)
Harmonic Distortion
Out of band interference
• Dynamic tests
– Phase and Amplitude Modulation
– Phase Modulation
– Linear Frequency Ramp
• Transient tests (NYI in Protection Suite)
– Magnitude step
– Phase step
Setting up a test - Hardware
(PC, F6150 and PMU each have IP addresses)
Protection Suite  F6150 : Waveform definitions, start time
Protection Suite  PMU : Request config, start transmission
F6150  PMU : Generated waveforms
PMU Protection Suite : Config response, phasor data stream
Summary
• Synchrophasors can be put as following in power
system protection and control.
SCADA
Wide Area
PMU’s Protection
Local Area
Local Point
Back up
Protection
Main
Protection
msec
sec
minute
Time
Summary
• PMUs and WAMS enable a new dimension of
monitoring power grid operation.
• Synchrophasors solve the problem of time
incoherency required for wide-area power system
control.
• situational awareness and alarming system will
help to avoid unwanted disturbance
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