EVI-DiST: Electric Vehicle Infrastructure – Distribution System Integration Tool

NREL's Electric Vehicle Infrastructure – Distribution System Integration Tool (EVI-DiST) provides high-fidelity modeling, analysis, and controls for grid-scale EV charging integration.

Electric utilities are responsible for delivering electricity to homes and businesses. Accelerating adoption of EVs is putting pressure on these companies to rapidly deploy strategies for managing grid stress from EV charging. NREL's EVI-DiST tool is uniquely designed to provide the insights utilities need to integrate additional EV chargers with the grid.

EVI-DiST can illustrate EV charging grid impacts at the feeder-level down to detailed secondary models at the residential and commercial building level. It has informed regional grid planning efforts with major public utility companies in more than five states.

Key Capabilities and Uses

EVI-DiST has the ability to:

  • Assess the impact of increasing EV adoption on electrical distribution systems, which provide electricity to homes and businesses
  • Provide high-fidelity modeling to utility planners so they can better prepare for increased EV charging loads
  • Allow utilities to evaluate the impact of both fixed control methods like time-of-use rate-based charging controls, as well as algorithms that integrate real-time grid conditions and vehicle responses in a dynamic and adaptive way.

EVI-DiST can evaluate the impacts of EV charging on service transformers (such as loading, winding hot spot temperature, and degradation), on primary feeder component capacities, and on service voltage profiles. It also provides descriptive statistics and allows users to compare the effects of different smart charge management strategies to mitigate peak loads.

Together, these capabilities enable utilities to pinpoint strategies to manage expected EV charging loads at scale.

This infographic demonstrates the modeling framework for EVI-DiST. A left-hand column defines the data inputs: Synthetic Load Profiles (ResStock/ComStock) and AMI smart meter data, NSRDB: National Solar Radiation Database, and inputs from EVI-Pro: EV Parameter, Charger parameter, Park location, Park start time, Park end time, Park start SOC, and Park end SOC. A second column illustrates that these data feed into three models: a Building Energy Model, a DER Model (PV, BESS), and an EV Charging Control Model. These models, plus Feeder Secondary Info, then inform modeling for a Distribution System Secondary Side Model (Household Loads plus Service lines). A third column shows that the service transformer level analysis produces transformer loading analysis, transformer life evaluation, and power quality evaluation such as the voltage drops on the secondary side. Nodal P/Q power values and a feeder primary model further inform a Distribution System Model (OpenDSS). Finally, these resources inform an ADMS/EV SCM Model which provides feeder-level analysis: A time series power flow analysis, a grid impact assessment, and SCM implementation and evaluation. Th power dispatch signals for controllable assets (EVs/DERs) are then back-flowed to inform the DER Model (PV, BESS).

User-Friendly Dashboard

The web-based EVI-DiST dashboard allows users to visualize their data in an interactive format. This open-source, modular, and flexible environment easily integrates with multiple public and commercially available tools, giving utilities a more holistic overview of EV charging impacts.

EVI-DiST currently integrates with EVI-Pro, DiTTo, HELICS, OpenDSS, ResStock, ComStock, CYME, and Synergy.

Publications

Analyzing Residential Charging Demand for Light-Duty Electric Vehicles in Colorado, NREL Conference Paper (2024)

Contact

To learn more about custom analyses using EVI-DiST or to explore related partnership opportunities, contact us at EVI-DiST@nrel.gov.

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