This document discusses reference node selection and angular baselining using synchrophasor measurements for real-time power system operation. It presents case studies on selecting different reference nodes and their impacts. The key considerations for reference node selection include choosing nodes with strong interconnections, reliable communication, close to base load generation, and high fault level. The document also discusses the need for angular baselining to validate data, distinguish normal and abnormal grid conditions, and generate alerts. Typical wide angle node pairs for baselining between generation and load centers as well as across regions are presented.

1. 22-Mar-17 Power System Operation Corporation Limited, India
Selection of Reference Node and Angular
Baselining using Synchrophasors Measurement
for Real Time Operation
Pradeep Kumar Sanodiya
Vivek Pandey
Rajkumar Anumasula
Chandan Kumar
Sunil Patil
Srinivas Chitturi
NASPI Work Group Meeting-March 2017

2. 22-Mar-17 Power System Operation Corporation Limited, India
Power System Operation Corporation Limited
is an Independent Company w.e.f.
3rd January 2017

3. Reference Node Selection
• Need for Selection of Reference Node
• Case Studies with different Reference Node
• Summary
Angular Baselining
• Angular Baselining Need & Case Studies
• Summary
Power System Operation Corporation Limited, India22-Mar-17
Outline

4. Power System Operation Corporation Limited, India22-Mar-17
Need for Reference Node Selection
• Required for Offline Power System Simulations
• Required for EMS/SCADA
• Similarly required for Synchrophasors based analysis

5. Power System Operation Corporation Limited, India22-Mar-17
Angular separation is vital in Wide Area Monitoring
System
• Assessing the stress in the grid
• Oscillation Monitoring
• Event Detection and localization
• Visualizing power flow pattern

6. Power System Operation Corporation Limited, India22-Mar-17
Case Studies with different Reference Nodes
➡ Case-1- Weak Vs Strong Bus as Reference Node
➡ Case-2- Bus with Unreliable Vs Reliable Communication as Reference Node
➡ Case-3- Reference Node Near Vs Far from Event Location
➡ Case-4- Reference Node away from HVDC
➡ Case-5- Reference Node near to Varying Generation Complex

7. Power System Operation Corporation Limited, India22-Mar-17
Case-1 : Weak vs Strong Bus as Reference Node
Grid 1
110 GW
Grid 2
40 GW
B
D
A
PMU Locations
Weak Bus as Reference
Strong Bus as Reference

8. Power System Operation Corporation Limited, India22-Mar-17
Case-2 : Bus with Unreliable vs Reliable Communication
as Reference Node
Data from one of the node is
non current
Reliable Communication
When PMU has taken as reference
whose data is not updating , Rest
of Angular Separation can not be
visualized
Unreliable Communication

9. 22-Mar-17 Power System Operation Corporation Limited, India
Case-3 : Reference Node Near vs Far from Event Location
B
A
C
D
E
F
G
H
JI
KL
PMU Locations
Event Occurred at Node C
which is near to Node A
Reference node distant from Event node Helps in
identifying the event location
Near Reference Node is A
Reference Node is BFar

10. B
A
C
D
E
F
G
H
JI
KL
Power System Operation Corporation Limited, India22-Mar-17
Case-4 : Reference Node away from HVDC
Ref
HVDC Link
HVDC Pole Blocking & De-blocking
M
PMU Locations

11. B
A
C
D
E
F
G
H
JI
KL
Power System Operation Corporation Limited, India22-Mar-17
Case-5 : Reference node near to Varying Generation
Complex
Ref
M
PMU Locations
High Hydro
Generation
Hydro generation varying and
Reference Node H is near to the
Varying generation Complex

12. Power System Operation Corporation Limited, India22-Mar-17
Summary
• Preferred locations for reference node
• Node with strong Interconnections
• Nodes with reliable communication
• Node close to base load Generation Complex
• Node with High fault level
• Nodes consistent with offline simulation/EMS studies
• Should be system-wide available and reliable
• Nodes to be avoided
• Nodes with Low inertia, Weak tie lines, Low fault level,
• Nodes located in Oscillation prone area,
• Nodes near to HVDC Bus,
• Nodes near to Varying Generation Complex

13. Power System Operation Corporation Limited, India22-Mar-17
Summary Contd…
• Reference node selection lookup table to be prepared
• Priority list for reference node selection based on above experiences.
• To be reviewed depending on Visualization and Application
Requirement and
• To be reviewed periodically

14. 22-Mar-17 Power System Operation Corporation Limited, India
Angular Baselining

15. 22-Mar-17 Power System Operation Corporation Limited, India
Need for Angular Baselining
• Validation of the data/Plausibility check
• To compare and validate angle limits with the state estimator
and offline load flow studies
• To distinguish between normal and abnormal grid
conditions-
• Discriminate seasonal off peak and peak stressed conditions
• For alarm generation to alert the operator

16. 22-Mar-17 Power System Operation Corporation Limited, India
Validation of the data/Plausibility check
Wide Variation in
Angular Separation
due to Leap Second
System Islanding or
Loss of time
synchronization

17. 22-Mar-17 Power System Operation Corporation Limited, India
Normal and Alert Grid Operation
FA
C
E
Bus-B
400kV Line765kV Line Line Open
PMU Locations
Bus E
B
Bus D
Bus F
GH
Bus G
Bus C
D

18. 22-Mar-17 Power System Operation Corporation Limited, India
Criteria for Selection of Angle Node Pairs
• Wide Area Node Angle Pair
• Generation complex to load complex
• Power Corridors/Flow Gates
• Power Corridors from One Region to Other.
• Maximum Angular Separation in the Grid(wide distant node).
• Adjacent Node Angle Pair
• Both ends angle should be available

19. Power System Operation Corporation Limited, India22-Mar-17
Typical wide angle pair for baselining
B
A
C
D
E
F
G
H
JI
KL
N
M
Node O : Generation Complex
Node N : Load Centre
O

20. 22-Mar-17 Power System Operation Corporation Limited, India
Typical wide angle pair for baselining Contd……
B
A
C
D
E
F
G
H
JI
KL
N
M
Flow Gate between
Node M and I
Max Angle-39
Min Angle-14

21. 22-Mar-17 Power System Operation Corporation Limited, India
Typical wide angle pair for baselining Contd……
B
A
C
D
E
F
G
H
JI
KL
N
M
Node B : Generation Complex
Node C: Load Centre

22. 22-Mar-17 Power System Operation Corporation Limited, India
Maximum Angular Separation Monitoring in the Grid
Angular Separation going Out of 90 Degree Range :
High Over drawal by One of the Region causing high
angular separation and stress in the Grid
During Normal Operation
maximum angle was 77
degrees all grid parameters
were with in limits

23. Power System Operation Corporation Limited, India22-Mar-17
Summary
• Angular Baselining helps in understanding the grid
condition during operational horizon.
• It helps in finding the various threshold for angle pairs for
monitoring and alarm generation.

24. 22-Mar-17 Power System Operation Corporation Limited, India
References
• https://posoco.in/download/synchrophasors-initiatives-in-india-decmber-2013-
web/?wpdmdl=713
• http://wrldc.org/Docs/Angular_separation_report/
• EIPP Performance Requirements Task Team, “Definition and Implementation of a
System-Wide Phase Angle Reference for Real-Time Visualization Applications”,
October 13, 2005.
• https://posoco.in/reports/system-reliability-indices/daily-angular-difference/daily-
angular-difference-2016-17/
• Eastern Interconnection Wide Area. SynchroPhasor Angles Baselining Study.
Mahendra Patel, PJM. Co-chair: NASPI PITT. (Planning Implementation Task Team)
• https://www.wecc.biz/Reliability/JSIS_AZ_PhaseAngleBaselining_BB-FA_011413-
D_FA%20Rev_aEPG.pdf

25. Email : psanodiya@posoco.in
WRLDC,POSOCO, Mumbai

Thank You
22-Mar-17 Power System Operation Corporation Limited, India