EMTP Modeling and Renewable Integration in Chile's National Power Grid

The Chile Power Grid is an extremely long and narrow system, and it is surpassing 70% instant power in participation from renewable inverter-based resources regularly during the daytime when photovoltaic power plants are at their zenith. This scenario results in typical values of 30 GVAs of inertia and local Short Circuit Ratios (SCR) below 1.5, in a system where these values were usually above 60 GVAs and 6, respectively. A weaker system is prone to wider, less damped voltage and frequency oscillations that arise from high-frequency modelling of components, which is neglected by Phasor Domain Transient solvers, also known as RMS simulations. Chile ISO is addressing this challenge by modeling, or integrate models, in EMTP every existing facility (OEM and standard), new more friendly Grid Following inverters, Grid Forming inverters, FACTS and HVDC projects.

Initially, the EMTP databases were built manually without little tracking of what was done and ongoing developments of the grid. Currently, the team is working on an automated version of database building. This reduces the time-consuming task on setting up operation points and minimizes human error while increasing the range of results. Additionally, it will be the main tool to migrate online variables from real-time measures like a SCADA system, allowing us to update the operation point of the EMTP database at regular intervals, e.g., every 15 min, so we are able to assess the system's reliability automatically and in real-time. This is what we call the digital twin.

The latest intervention involes discussions to update the National Grid Code regarding inverter-based resources, including requirements to increase transient stability reliability and tests that need to be passed by the EMTP models handed over to the ISO. To this end, we have been working closely with PGSTech to demonstrate the expected responses from standardized Grid Forming models. A by-product of these models will be to test Chile Power Grid to its limits: increasing renewable participation percentage and displacing synchronous conventional generation, thus reducing conventional inertia and SCR.

Author: Simon Veloso
Company: COORDINADOR

If you need more information : www.emtp.com

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