1. PSSE Playback Model Validation with PMU Data
Damien Sommer, P.E.
Senior Transmission Planning Engineer

2. ATC Footprint

3. DATC Transmission in WECC

4. PSSE Playback Feature Model will be available in PSS®E version 34.1
The model is supplied as part of PSS®E installation; therefore, use of this model will not require compilation and link.
For version 33 users a .dll file can be downloaded from the Siemens PTI website

5. Time, voltage, frequency
PSSE Playback Feature
This model plays back a known set of voltage and frequency signals.
The PLBVFU1 model acts as a generator model. In using this generator model, do not attach an AVR or governor model to the machine associated with the PLBVFU1 model.
The played-in voltage and frequency signals must be described in a file as shown below, with each sample described in a separate record and the values in each line separated by spaces or commas:
Time, voltage, frequency

6. PSSE Playback Feature
The file containing the measurement has to be supplied in a file with an extension “.plb”. The file name (without the “.plb” extension) has to be less than or equal to 12 characters long for PSSE v 34 and less than or equal to 2 characters for PSSE v 33. This file has to exist in the working folder. If the “plb” file is not found, the PLBVFU1 model will keep the internal voltage and frequency fixed at the initial value (i.e., the playback feature will be ignored).

7. PSSE Playback Feature
The voltage signal which is played back is the internal (Thevenin) voltage of the playback generator. The ZSORCE of the generator used to represent the PLVFBU1 model should be non-zero.
The sampled voltage and frequency values may be smoothed via a first order block with time constants Tv (for voltage signal) and Tf (for frequency signal).

8. PMUs On ATC Transmission System
21 PMUs on high side of GSUs:
9 Coal
4 Combined Cycle Gas
2 Nuclear
4 Wind Farms
2 HVDC terminals

9. Python Script v1 – User Input Data
baseCase = ‘Large_Coal_Unit_v33_ '
plbfile = 'AA'
dyrfile = 'Large_Coal_Unit_v33_ '
csvoutfile = ‘Large_Coal_Unit.csv'
testGenNum =
testGenID = ‘1'
equivFrom =
Vnom = 345

10. Python Script v1 – Mini State Estimation
Retrieve initial conditions recorded by PMU at POI
Sets the initial conditions in the simplified case to those observed by the PMU at the POI
Save case with initial conditions as temp.raw

11. Python Script v1 – Run and Output
Run simulation using PMU data to define playback unit response
Creates channel files for voltage, frequency, active power and reactive power at POI bus where PMU was recording
Outputs a .csv file with data for each channel

12. Playback Simulation Process
place PMU data .csv file, PSSE files, Python script in event folder
Save .csv file as .plb file
Run script (takes about 30 seconds)

13. Example 1: Large Coal Unit, Line Faults
Simplified Model Used in Playback Runs:

14. Demonstration

15. Example 1: Large Coal Unit, Line Faults Event 1

16. Example 1: Large Coal Unit, Line Faults Event 2

17. Example 1: Large Coal Unit, Line Faults Event 3

18. Example 1: Large Coal Unit, Line Faults Event 4

19. Example 2: Large Coal Unit, Large Unit Trip Event 1
If monitored unit is not dispatched to PMAX governor PMAX value in .dyr file will likely have to be updated
Values in MMWG case
Unit MVA = 825
PMAX = 634
IEEEG1 governor model
PMAX (pu on machine MVA rating) = (~700/825)
PGEN = ~500 MW during this event

20. Example 2: Large Coal Unit, Large Unit Trip Event 1, PMAX = 0.847

21. Example 2: Large Coal Unit, Large Unit Trip Event 1, PMAX = 0
Example 2: Large Coal Unit, Large Unit Trip Event 1, PMAX = (Pgen / MVA)

22. Example 2: Large Coal Unit, Large Unit Trip Event 1, PMAX = 0.615

23. Example 2: Large Coal Unit, Large Unit Trip Event 3, Oscillations

24. Example 3: Combined Cycle Plant, Large Unit Trip – CT1 First Pass

25. Example 3: Combined Cycle Plant, Large Unit Trip – CT1 First Pass
If using actual bus numbers and reusing the same python script check channel numbers
PSSE orders model information by bus number ascending order
If gen bus number is larger than POI bus number in one raw file but smaller than POI bus number in another raw file your exported channels will be different

26. Example 3: Combined Cycle Plant, Large Unit Trip – CT1 Second Pass

27. Example 3: Combined Cycle Plant, Large Unit Trip – CT2

28. Example 3: Combined Cycle Plant, Large Unit Trip – ST

29. Example 3: Combined Cycle Plant, Line Fault – CT1

30. Example 3: Combined Cycle Plant, Line Fault – CT2

31. Example 3: Combined Cycle Plant, Line Fault – ST

32. Example 4: ~300 MW Coal Unit Line Fault Event

33. Example 5: ~300 MW Coal Unit Trip of 850 MW Unit in Remote Location

34. Example 6: ~600 MW Nuclear Unit Trip of 1200 MW Unit in Remote Location

35. Example 7: ~600 MW Nuclear Unit 345-kV Line Fault

36. Harder Configurations to Validate: Gas Plant with PMU at Shared POI

37. Harder Configurations to Validate: Gas Plant with PMU at Shared POI
PMU is on the POI bus and thus captures the output of both units simultaneously
Version 2 Python Script required
Investigate PI Historian data on the two units and set one plant P and Q output to initial output
Fix the P and Q of the second unit with state estimation in in the python script

38. Harder Configurations to Validate: Wind Farm with Multiple Var Sources

39. Harder Configurations to Validate: Wind Farm with Multiple Var Sources
PMU is on 138-kV Bus, there is a DSTAT model and switched shunt device on the 34.5-kV bus
Cap Bank on unit bus is supposed to be manual set in the model based on wind unit output
PI Historian data will have to be pulled to find starting points for wind unit, switched shunts and DSTAT model

40. Conclusion
Still early in process of validating units but so far we haven’t found any events where the models matched reality very well
This is a very important tool to help get us to better models
More work is needed with GOs to improve models

41. Contact Information
Damien Sommer, P.E. (262)

42. Questions