1. Harsh Vardhan harsh.vardhan@alstom.com
Performance evaluation of Phasor Measurement Units for digital substations (PMU with IEC sampled values)
Harsh Vardhan

2. Objectives
Application of IEC Process Bus in Synchronized Phasor Measurements Systems
Assembly and testing of a PMU using Sampled Values (SV) for acquiring data
Presentation and discussion of test results for "PMU with SV“ under different scenarios
Real electrical system measurements at low voltage (MedFasee Project)
under Normal system operation
under disturbance
Laboratory tests

3. The Digital Substation
PMU with SV

4. The Merging Unit
IEC LE sampled values (SV) and IEC GOOSE interface
Operates with protection profiles (80 samples/cycle) and measuring (256 samples/cycle)
Sampling stability guaranteed by hardware
Synchronization via Ethernet PTPv2 or via IRIG-B
Use of VLANs and priority tags (802.1Q)

5. IEEE C definitions
TVE (Total Vector Error):
FE (Frequency Error):
RFE (Rate of Change of Frequency Error):

6. Assessment Standards - Dynamic Testing
Delay time:
Transition delay of the measured variables
Response time:
Errors stabilization time
Source: IEEE C

7. Test System Architecture:
Comparison of Synchrophasors measured by the "PMU with SV" and the “conventional PMU”
System under normal operation conditions
System under disturbance

8. Measurements - Normal System Operation
0.01%
0.31 deg

9. Measurements - Normal System Operation
1.7mHz

10. Measurements - Under Disturbance

11. Measurements - Under Disturbance

12. Measurements - Under Disturbance

13. Laboratory Tests Rates: 20 FPS 60 FPS Class M limits: Architecture
IEEE C
C a IEEE-2014
Steady state test: Change Frequency, and Angle Module
Dynamic test: Step magnitude and Angle
MU SV profiles:
Protection Profile (PP) –
80 samples/cycle
Measuring profile (PM) -
256 samples/cycle
Architecture

14. Laboratory Tests Frequency range: 55 Hz to 65 Hz (1 Hz steps) 20 FPS
20 FPS
60 FPS
TVE (%)
FE (mHz)
RFE (mHz/s)
Maximum Limits
1,00
5,00
100,0
PMU SV (PP)
0,26
0,57
14,65
0,20
1,29
108,5
PMU SV (MP)
0,35
0,71
16,57
0,28
0,84
60,20
PMU conventional
0,48
14,88
0,21
0,89
56,99

15. Laboratory Tests Magnitude and angle Variations: 10% to 120% Vn
10% 200% In
Limits
TVEmáx = 1,00%
Magnitude Variation
Angle Variation
20 FPS
60 FPS
PMU SV (PP)
0,35
0,90
0,08
0,09
PMU SV (MP)
0,39
0,36
0,13
0,06
PMU conventional
0,47
0,46
0,10
0,07
Observation: Larger TVEs found at lower current levels (10% In).

16. Laboratory Tests PMU SV (PP) PMU SV (PP)
Magnitude and angle Variations - 20 FPS:
Delay time
Equipment
Magnitude
Angle
Limits
12,5ms
PMU SV (PP)
5,0ms
PMU SV (MP)
PMU conventional
Overshoot
Equipment
Magnitude
Angle
Limits
10%
PMU SV (PP)
0,20%
0,60%
PMU SV (MP)
0,36%
PMU conventional
0,17%
0,72%
Response time
Equipment
Magnitude Step
Angle Step
TVE (1%)
FE (5mHz)
RFE (100mHz/s)
Limits
0,35s
0,70s
PMU SV (PP)
0,10s 0s
0,12s
0,21s
0,25s
PMU SV (MP)
0,26s
PMU conventional
0,08s
0,38s

17. Laboratory Tests PMU SV (PP) PMU SV (PP)
Magnitude and angle Variations - 60 FPS:
Delay time
Equipment
Magnitude
Angle
Limits
4,17ms
PMU SV (PP)
1,67ms
PMU SV (MP)
PMU conventional
Overshoot
Equipment
Magnitude
Angle
Limits
10%
PMU SV (PP)
0,56%
0,37%
PMU SV (MP)
0,35%
0,41%
PMU conventional
0,52%
0,34%
Response time
Equipment
Magnitude Step
Angle Step
TVE (1%)
FE (5mHz)
RFE (100mHz/s)
Limits
0,117s
0,2330s
0,233s
PMU SV (PP)
0,032s 0s
0,038s
0,085s
0,115s
PMU SV (MP)
0,082s
PMU conventional
0,002s
0,035s
0,112s
0,128s

18. Key Findings Feasibility of using MU in SMSF
The "PMU with SV" reproduced faithfully the Synchrophasors measured by “conventional PMU” in various power system operating conditions and in laboratory tests.
The measurement profile (PPC 256) proved the most suitable for use with PMUs
Larger TVEs found at lower current levels (10% In).
PMUs using SV (IEC LE) allows the calculation of Synchrophasors from optical Instrument Transformers
Since 02/2014 the Synchrophasors at the "UFSC" point in the SMSF BT MedFasee project are measured by a "PMU with MU"

19. Thank You!
Questions?