1. Synchrophasor: Implementation,Testing & Operational Experience
Uttam Mishra
Doble Engineering Company

2. Operational Experience
Presentation Topics
What is SynchroPhasor
Applications
Testing PMUs
Operational Experience
Conclusion

3. Phasor Measurement Unit
Definition : Phasor
Phasor is a vector which has magnitude and angle
Corresponds to a sinusoidal waveform θ

4. Phasor Measurement Unit
PMU typical configuration:

5. Phasor and Synchro Phasor
Time aligned Phasor : Synchro Phasor
GPS satellites provides time stamp
Time aligning helps to analyze system events G Zs 21 θ

6. Total Vector Error Error Expected Phasor Actual Phasor Ref
𝐓𝐕𝐄 % = Length of Error Phasor Length of expected Phasor
In illustration, actual phasor is off in both magnitude and angle.
1% TVE ≈ .573 degrees (.01 * 360 / 2π)
≈ 26.5 μs (at 60 Hz)

7. Back up applications Power system stability
Two ended fault location algorithm
System diagnostics
Distributed Busbar protection
Load shedding
Wide area frequency monitoring

8. 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

9. PMU : Power Swing Calculate the angle difference due to disturbanceZs 21 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

10. 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

11. CFE Network

12. 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

13. CFE Network Ʃ + - Remote Phasor Local Phasor Threshold Trip Selected
PU Cyc
Trip Selected
Generators

14. Europe System Disturbance: November 4, 2006

15. Grid Islanding 10 GW surplus 8.9 GW deficit 51.4 Hz 49 Hz

16. Resynchronisation
A number of uncoordinated unsuccessful attempts made without knowledge of the overall UCTE situation
Full resynchronisation after 38 minutes
Source: UCTE

17. 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)

18. 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.

19. 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.
Frequency Deviation and ROCOF are just numbers; tolerance is expressed as an absolute deviation from expected.
Rather than express separate tolerances for phasor magnitude and angle, TVE% is introduced.

20. 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

21. IEEE C37.118.1 Requirements Steady state tests Dynamic tests
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
Continuous phase test is equivalent to a frequency test that deviates slightly from nominal
Harmonic distortion and out of band interference should not effect the PMU phasor report of the fundamental signal
Modulation tests should be reflected in the PMU reported phasors
Tolerances for transient tests are expressed in terms of response time, delay time, max overshoot/undershoot

22. 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
Connect F6150 source outputs to PMU inputs (3V + 3I)
PMU may need to be configured to allow connection from PC (e.g. SEL)

23. Summary
Synchrophasors can be put as following in power system protection and control.
SCADA
Wide Area
PMU’s Protection
Local Area
Back up Protection
Main Protection
Local Point
msec
minute
Time
sec

24. 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