Transmission Modeling and Analytics

Models, tools and methods to ensure resilient, reliable and clean transmission networks.

Research and Development Challenges

EPRI’s Transmission Planning research area supports the development and validation of planning study models, planning processes and frameworks, and reliability and resiliency assessment analytics. These are required to build a reliable, resilient, and economic transmission grid that integrates an evolving generation mix to supply an increasingly complex load, that can also act as a system resource. A major focus is on accurately representing emerging loads—such as EV charging stations, data centers, and hydrogen electrolyzers—alongside enhancements to the composite load model and support for utility adoption. Measurement-based approaches are being developed to improve load modeling accuracy, while aggregated DER models are being refined to support FERC Order 2222, ensuring better representation of distributed resources in transmission planning. Significant advancements are also being made in modeling and control of HVDC systems, including offshore wind integration and grid-forming capabilities. Generic models for FACTS and HVDC are being updated to reflect evolving system dynamics. Stability analysis is being strengthened through improved screening methods and new guidelines for sub-synchronous oscillation (SSO) analysis in EMT environments. Tools like the Advanced Reliability Toolset (ARTS) are being enhanced to support high-IBR systems, with improvements in contingency screening and node-breaker modeling using EMS data. On the planning front, frameworks such as the Resilient System Investment Framework (RSIF) and High Level Screening (HiLS) tool are being upgraded to support decarbonization pathways. Automated powerflow case creation and coordinated expansion planning tools (JHSMINE and ACEP) are being refined for co-optimization. Data analytics and outage statistics are being leveraged to improve reliability assessments, while topical webcasts and insights are being offered to keep stakeholders informed. Power quality and harmonic compliance remain critical, with updates to tools like GICHarm and B2E, and new guides addressing flicker, TRV, lightning transients, and temporary overvoltage. IBR harmonic models and study guides are also being revised. Finally, planning frameworks like CPLANET are being enhanced to integrate Grid Enhancing Technologies (GETs), with updated reference guides supporting their deployment. Collectively, these efforts aim to ensure grid reliability, resilience, and adaptability in the face of rapid technological and structural change.

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Related Deliverables

Validation of Reduced System Models

3002029744

Summarizes impedance scanning techniques to validate reduced models.

Inverter Interaction Screening

30020297824

This document strategizes how to pre-emptively screen for inverter interactions and plan for mitigation as required.

Impedance Characterization of PE Loads

3002029829

Assessing stability impact of large PE loads on power system using impedance characteristics.

GDO Reference Guide

3002029831

A reference for creating geomagnetic disturbance (GMD) operating guidelines.

Transmission Solution Software (CPLANET)

3002029839

Ooptimized transmission solutions that combined advanced transmission technologies, energy storage and conventional projects.

Advanced Methods for TRA

3002029834

Ooptimized transmission solutions that combined advanced transmission technologies, energy storage and conventional projects.

Line Rating in Transmission Planning

3002029841

Analyze the implications of using advanced line rating technologies, such as AAR and DLR, for long-term transmission expansion planning

HVDC Planning Guide - 2024 Update

3002029844

Summary of HVDC planning processes, study types, and modeling and simulation tool guidelines.

System Impact of HVDC Connections

3002029847

Provides insight into system reliability implication of HVDC links, identifies mitigation options, including advanced use of converter control capabilities.

IBR Short-Circuit Network Equivalencing

3002030169

Documents results of network equivalencing methods for fault and protection studies in systems dominated by IBRs.

IBR SC Modeling

3002030170

Summarizes the latest research and developments in short-circuit modeling of inverter-based resources.

GFM IBR Protection

3002030171

Analyzes the impact of grid forming inverters on system protection.

Modeling of IBR and Load Interactions

3002030173

Summarizes the latest research on inverter-based resources and load interactions.

Boundary between EMT-RMS Domain TI

3002030470

The aim is to identify the characteristics that can help define the boundary between EMT and RMS domains.

Modular Eigenvalue Analysis

3002031345

Provides an overview of a modular technique to evaluate small signal stability of the power system.

Grid Strength Assessment Tool

3002030167

Helps in evaluating various system strength metrics during planning.

Key projects and Related Efforts

Area Leads