Page Content

Modelica

Modelica is an object-oriented, declarative, multi-domain modeling language for component-oriented modeling of complex systems.

For more information please refer to: https://modelica.org/

FMI

The Functional Mock-up Interface (or FMI) is a standardized interface protocol which enables computer simulations tools to integrate different models developed by Modelica language into their own environment.

For more information please refer to: https://www.fmi-standard.org/

FMU

Functional Mock-up Unit (FMU) is a zip file which includes the compiled binary code of the Modelica model as well as an XML file which includes the information about the model (number of parameters/states/inputs/outputs, name of these parameters, ...) required by FMI standard to connect to the model externally. The FMU can also include other files which might be required by a specific external tool.

Development Environments

Various commercial and open-source tools are available as Modelica developments environments that are complied with FMI standard to export FMUs.

A comprehensive list of available tools can be found in this web page: https://fmi-standard.org/tools/

ePHASORSIM is compatible with two of these tools: OpenModelica and Dymola

OpenModelica is an open-source Modelica-based modeling and simulation environment intended for industrial and academic usage. Its long-term development is supported by a non-profit organization, “Open Source Modelica Consortium (OSMC)”.

For more information please refer to: https://www.openmodelica.org/

Dymola is a commercial tool that requires purchasing a licence.

For more information please refer to: https://www.3ds.com/products-services/catia/products/dymola

FMUCreator

The FMUCreator is a customized tool developed by OPAL-RT to compile FMUs from Modelica Models which are compatible with ePHASORSIM solver.

GenUnit FMU

A GenUnit (Generator Unit) is a combination of only one current injector component and its required Controller components. A GenUnit must have at least one Power Pin.

The figure below illustrates a typical GenUnit which is made in OpenModelica. As can be seen, this GenUnit has a salient pole type synchronous type generator (GENSAL) as the current injector device and three controllers which are HYGOV (Hydro turbine-governor model), EXST1 (IEEE Type ST1 excitation system) and IEEEST (IEEE stabilizing model).

Open

Modelica Model Composition

Current Injector Component

A current injector is a component which can be modelled as a current source. These are basically the components which generate (such as synchronous machines), absorb (such as loads) or transfer (such as transmission lines) electrical energy directly to/from the power system. From ePHASORSIM’s perspective, any model with at least one power pin is considered as a current injector.

Controller Component

A controller is a component which controls specific signals of the current injector component. Exciters, turbine-governors and power system stabilizers are typical examples in this category. A GenUnit is a combination of controller(s) and current injector devices.

Power Pin

A power pin is a connector type class which includes variables for both voltage and current of a component. If two or more power pins are connected together, Modelica’s translator automatically generates equations for voltage equality as well as Kirchhoff’s Current Law (KCL) for this connection.

Power pins are used to interface with powers system buses in ePHASORSIM simulations. They must follow a strict naming convention: bus0 for the first power pin, bus1 for the second, and so forth.

Interface Pin

An Interface Pin is used to set an input value for the FMU model that is expected to be changed during simulations. A common use case is for signals like TRIP for a generator which is specified in the outer scope (GenUnit level) of a model.

Single Component FMU

A single component FMU implements a single controller function rather than a whole generating unit (see https://opal-rt.atlassian.net/wiki/spaces/EUD/pages/23200436/Terminologies#GenUnit-FMU ).

Single component FMUs can be of the following types: Exciters, Power System Stabilizers, Turbine and Governors, and Minimum & Maximum Excitation Limiters.

The routing of control signals between these controllers and the machine are hard-wired by the ePHASORSIM solver. In case a custom control structure or routing is required, a full GenUnit FMU should be used.

FMUGlossary (deprecated)

A *.csv file which includes the name, type and parameters of the supported Modelica components.

FMU Mapping File

FMU mapping files define the mapping of parameters from an external model format such as PSS/E, PowerFactory or PSCAD to the Modelica parameters of the FMU.

YAML Format

It is now possible to import user FMUs and map the Excel, PSS/E or Powerfactory parameters to that FMU using a .yaml mapping file when importing models using the Unified Database.

This feature replaces the old .csv mapping files.

For more details on the usage of *.yaml files, please refer to YAML Mapping Files.

CSV Format (deprecated)

ePHASORSIM uses different mapping files in *.csv format to map parameters of a component in PSS/E, CYME or PowerFactory to the corresponding component define in FMUGlossory.csv.

These files are as follows:

For more details please refer to Importing from PSS/E, CYME and PowerFactory