Operational Technologies
Building and maintaining an external model
May 19, 2021

While the primary focus for EMS modeling is on a company’s own electric system, an external model of neighboring electric systems is needed to support the internal EMS operations of the company.

Importance of the external model

Benefits of an external model include:

  1. Obtaining an accurate solution, a state estimator or power flow solution, to better represent the internal system that is being modeled.
  2. Providing better situational awareness so that contingent impacts to the internal model can be more accurately studied.
  3. Communicating more effectively with neighboring areas, utilities and RCs.

External model maintenance

To ensure the accuracy of the external model, the model will require periodic updates to reflect changes that have been made by neighboring utilities. Maintenance of the external model by hand can be extensive and time-consuming so automating the building of the external model is paramount so the external model can be refreshed with reduced labor.

How to update an external model faster and more reliably

PSC helps clients automate the build of external models by offering end-to-end services related to modeling, including:

  • Supporting the collection of data for the external model from models used by neighboring utilities, ISOs/RTOs, Balancing Authorities and Reliability Coordinators
  • Establishing naming conventions
  • Extracting equipment and topology from the collected data using PSC tools
  • Stitching the external and internal models together
  • Constructing tables of station names
  • Adding measurements to external substations using PSC tools
  • Reducing or replacing a larger external model with equivalent smaller networks

PSC leverages in-house external model build scripts as well as working experience with GE Source, Siemens IMM, ABB Hitachi, Powerinfo CIMSpy, and other CIM-based tools to help clients build, improve, and maintain accurate models.

PSC can also provide external modeling guidance to help achieve accurate solutions for the internal model and its boundaries. Please contact us for more information.