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Reference Number: AA-01866// Views: AA-01866// Created: 2023-11-22 08:15:00// Last Updated: 2024-01-12 09:22:03
General Article
[ePHASORSIM] concept of a OpenModelica GenUnit FMU linked to PSSE network data

This article is covering the software architecture when linking a GenUnit FMU with PSS®E network in ePHASORSIM.

This article is assuming the model of a GenUnit is already created in Open Modelica.

This article is assuming that OpenModelica 1.9.1 was successfully installed and compiling the OpenModelica model into a FMU was succesfull as described here: 

https://www.opal-rt.com/support-knowledge-base/?article=AA-01578


 

With ePHASORSIM it is also possible to import power system models from third-party software such as PSS®e, CYME and Power Factory. For each of these software, many components are supported in ePHASORSIM but not all of them. The list of supported components for each software can be found here:
https://opal-rt.atlassian.net/wiki/spaces/PEUD/pages/144473156/PSS+e+DYR+file


For any component that does not exist in the built-in library of ePHASORsim, but exists in the library of PSS®E it is possible to create a FMU and expand the built in library of ePHASORsim.

The Siemens PSS®E data format is a widely used for power system simulation. PSS®E uses a variety of plain-text files to store data for different actions:

·     The RAW format (with file extension .raw) is used to store the steady-state data for power flow analysis

·     The DYR format (with extension .dyr) is used to store the parameters of dynamic devices for transient simulation.

The following article describes the connection of the GenUnit FMU with the .dyr and .raw file in the software architecture of ePHASORSIM using example 16 of ePHASORSIMs library.

The phasor16_WECC example uses a PSS®E network as input data. This network contains on bus 184 a GenUnit, which is created out of the single components WT4G1 and WT4E1. 

 

The .dyr file of PSS®E contains all single units connected to a bus, whereas ePHASORSIM requires a GenUnit compiled as .fmu and this GenUnit then contains the single units.
The phasor16_WECC example has herefor the WT4G1_WT4E1.fmu, which is the GenUnit consisting the two single units WT4G1 & WT4E1.


This .fmu file is the compilat of the OpenModelica Model WT4G1_WT4E1.mo, which is part of the OpenModelica library provided by OPAL-RT.

Information about the GenUnit can be gained by opening this model in OpenModelica or Dymola. (Below a screenshot of OpenModelica).
Here the Pin dPref and the connection to the PSS®E network via bus0 can be seen directly.

Every single unit of the GenUnit has parameters for configuration.
Opening WT4G1 in OpenModelica is showing 17 REAL parameters.

These parameters must be registered in the FMUGlossary.csv placed in the RT-LAB installation folder.
EG here: C:\OPAL-RT\RT-LAB\2023.2.1\FMUCreator\FMUCreator\resources\FMUGlossary
 
For WT4G1 the component type 1 can be seen.

In total 7 types of components exist which are described under:
https://opal-rt.atlassian.net/wiki/spaces/PEUD/pages/144473364/Register+Component+in+FMUGlossary

After the component type, the next column represents the total number of parameters, and the columns that follow are the names of those parameters.
In the screenshot above, we see that the first parameter is P_gen, then Q_gen and so on.
T
he order of the parameters in the FMUGlossary is crucial, since they are mapped to the sources in the model by a separate mapping file.
In the case of PSS®E, this is the PSSEv32_mapping csv. If we look in this file for the WT4G1, we can see that P_GEN will be mapped to r2, since this is the first source in the csv:

Note that in this case, the source r2 comes from the .raw file,


Every prefix is indicating the source of the parameter. The source can be the .dyr file, the .raw file or ePHSAORSIM itself. For PSSe the prefixes are described here:
https://opal-rt.atlassian.net/wiki/spaces/PEUD/pages/144605601/Importing+from+PSS+e+CYME+and+PowerFactory
 
The Pins and Parameters of the GenUnit can be accessed via simulation by defining a Pin to it.
The excel Pin sheet of ePHASOR16 has following Pins listed:


Here the naming convention for outgoing Pins is as following:
gen_184_1/wt4g1_base1.PELEC ->  GenUnitID/Component_name.Pins_name
The GenUnitID is gen_184_1-> gen for GenUnit on bus 184 of machine ID 1
The Component_name can be taken from the OpenModelica model.

The Pin PELEC is then an outgoing parameter of  wt4g1_base1


For further information:
The creation of GenUnits is documented here:
https://opal-rt.atlassian.net/wiki/spaces/PEUD/pages/144605727/Create+a+GenUnit
How to create a GenUnit out of Single Components in Dymola can be found here:
https://www.opal-rt.com/support-knowledge-base/?article=AA-02041