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PRECISE: Preconfiguring and Controlling Inverter Set-Points Tool

NREL's PREconfiguring and Controlling Inverter SEt-points (PRECISE™) tool is a standalone system that enables autonomous operation of distributed energy from advanced inverters.

Developed in partnership with Sacramento Municipal Utility District (SMUD), PRECISE helps utilities in the United States and beyond by identifying optimal inverter modes and settings. Ultimately, it maximizes the cost-effective use of installed solar systems.

PRECISE, Step 1: PV Interconnection Application, Action: PRECISE obtains address of interconnection request. Step 2: Distribution Feeder, Action: PRECISE models the distribution feeder. Step 3: Model Secondaries, Action: PRECISE models secondaries using open street maps or GIS data. Step 4: Access AMI/SCADA data, Action: PRECISE performs load allocation and generates PV profiles. Step 5: Configure Inverter Limits, Action: PRECISE configures reactive power limits, active power limits, and power factor limits. Step 6: Run Analysis, Action: PRECISE runs analysis and exports the results.

PRECISE helps utility engineers to seamlessly interconnect and integrate high penetrations of photovoltaic (PV) generation on today's grid in a safe, cost-effective, secure, and reliable way. As soon as a customer applies for rooftop or ground-mount PV system installation, utility operators can use PRECISE to identify exactly where the correct feeder is located based on the customer's interconnection address. A utility operator can then use PRECISE to model the distribution feeder and preconfigure advanced inverter modes that help provide grid support.

Utilities gain the value of grid services—such as leveraging active power curtailment for voltage regulation—by optimally configuring setpoints based on locations, clusters, and seasonal weather patterns. Meanwhile, customers gain the value of having greater access to installed distributed energy systems.

Tool Modules

The PRECISE platform has a quasi-static time series (QSTS) capability, combined with mathematical optimization. The tool has three modules that operate in a specific order to identify optimal advanced inverter modes.

Distribution Power-Flow Module

The distribution power-flow module provides distribution operators an interface to view the network topology, geographical location of the requested PV system, and other existing PV systems. Additional requirements include:

  • User capability to perform basic power-flow analysis
  • GIS/Synergi to OpenDSS model conversion
  • Ability to take inputs from users on size of PV system, location of PV systems, and PV inverter hardware capabilities
  • Ability to choose any advanced inverter mode from the available set.

Advanced Inverter Mode Optimization Module

Based on which PV interconnection request will be preconfigured, this module will identify the optimal advanced inverter mode. Physical hardware limitations—such as power-factor limits or reactive power limits—must be respected when using this module. It is recommended that slopes of Volt/VAR-W curves stay within the manufacturer's allowable stable limits.

Visualization and Data-Ingestion Module

The two other modules will be integrated with this module.


Adarsh Nagarajan

Research Engineer | 303-275-4585