# Real-time frequency based reduced order modeling of large power grid

## TL;DR

This paper presents a real-time reduced order modeling method for large power grids using frequency-dependent network equivalents and TSA, enabling efficient electromagnetic simulations while preserving essential system behaviors.

## Contribution

It introduces an online RLS-based method to develop FDNE models in the z-domain and combines them with TSA for real-time power system simulation.

## Key findings

- Effective real-time reduced order models for large power grids.
- Preservation of electromechanical and high-frequency behaviors.
- Demonstrated using real-time digital simulators.

## Abstract

Large power systems are complex and real-time modeling of the grid for electromagnetic simulation (EMT) studies is impractical. In general, there are methods that reduce large power system into an equivalent network that requires less computational resource, while preserving electromechanical (low frequency) and high frequency behavior of the original system. This can be achieved by modeling the area not of interest (external area) as a combination of Transient Stability Analysis (TSA) type phasor model equivalent and Frequency Dependent Network Equivalent (FDNE). TSA retains electromechanical behavior, whereas FDNE retains high frequency behavior of the original power system. To this effect, this paper introduces a method of developing FDNE based on an online recursive least squares (RLS) identification algorithm in z-domain, and modeling of reduced power systems as FDNE and as a combination of TSA and FDNE using real-time digital simulators.

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Source: https://tomesphere.com/paper/1907.10273