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.

Related Projects

System Planning Methods, Tools, and Analytics

This project set supports the reliable integration of inverter based and distributed energy resources in transmission planning and protection activities. The research effort develops models and tools for the assessment of onshore and offshore wind, PV, battery energy storage, hybrid plants, and DER in bulk system planning and protection studies. Updated versions of models and tools including short circuit modeling, weak grid analysis and tools, relay settings and grid forming convertors are delivered to members, resulting in reduced engineering time for studies as well as improved models and study tools to ensure bulk system reliability.

Model Development, Validation, and Management

This project set addresses the need to develop generic, publicly available models that accurately capture the aggregated dynamic response of loads, power electronic-based transmission technologies, as well as aggregated DER for dynamic studies. The research is performed in close collaboration with industry stakeholders – WECC, NERC, software vendors, and equipment vendors in addition to transmission planners

Special Assessments for Transmission Planning

This research addresses specific issues in the planning process beyond power flow and stability analyses to address challenges posed by ascendance of inverter-based resources, more power electronics-based transmission technologies, and increased vulnerabilities due to extreme events. This project set provides a repository of topics that includes geomagnetic disturbance analysis, harmonic modeling and analysis for transmission systems, electromagnetic transient modeling and studies, and modeling and analysis for sub-synchronous oscillations for transmission systems.

Analytics for Emerging Transmission Planning Needs

This project set focuses on developing new analytics using state-of-the-art approaches and data analytics to help planners save time and resources to make planning decisions. The topics include integration of Grid Enhancing Technologies (GET) in transmission, integration of HVDC technologies specially in the context of off-shore wind and remotely connected renewables, and tools for automated contingency generation and screening of a large number of contingencies for system reliability assessments.

System Planning Methods, Tools, and Analytics

Supports the integration of inverter-based and distributed energy resources in transmission planning and protection. It develops models and tools for assessing wind, PV, battery storage, hybrid plants, and DER in bulk system studies. Updated tools, including short circuit modeling, weak grid analysis, relay settings, and grid-forming converters, are provided to members, reducing engineering time and improving system reliability.