The Electric Power Research Institute (EPRI), in partnership with the National Renewable Energy Laboratory (NREL) and Sandia National Laboratories, is developing an interconnection screening methodology that takes into account individual distribution feeder characteristics. Distribution modeling and simulation techniques will be used to determine the level of photovoltaics (PV) that can be accommodated on individual feeders without impacting distribution system operations. This measure of "hosting capacity" is expected to become more critical as PV deployment increases.

Major California utilities including Pacific Gas & Electric, Southern California Edison, San Diego Gas & Electric and the Sacramento Municipal Utility District are part of the project research team. These utilities will help to detail which tools and penetration screens are most commonly used and which procedures have been most effective for evaluating PV interconnection requests in California. The utilities will also help review distribution feeder classification methods currently used in California to identify and map areas with additional capacity for hosting PV.

Some of the factors known to be important to feeder hosting capacity, and included in the screening methodology, are steady state voltage regulation limits, tap changer cycling issues, reverse power flow issues, unintentional islanding risks, fault current contribution issues, ground-fault relaying desensitization issues, neutral grounding compatibility, ground fault overvoltage issues, and harmonics. These factors will then be used to develop a higher-level screening methodology that can be applied to other distribution systems, without necessitating the need for detailed analysis.

• FINAL Report: Alternatives to the 15% Rule. Smith, J., et al. EPRI. December 2015.  PDF (2 MB)

• FINAL Report for Tasks 7 & 8: Alternatives to the 15% Rule: Modified Screens and Validation. 3002005791. Smith, J., Project Manager. July 2015.  PDF (2 MB)

• Task 5 & 6 Update:Modeling and Hosting Capacity Analysis of 16 Feeders. 3002005812. Smith, J., Project Manager. Technical Update. April 2015.  PDF  (10 MB)

• EPRI. Final Technical Report: Clustering Methods and Feeder Selection for PV System Impact Analysis. Palo Alto, CA. March 2014. 3002002562. PDF (1 MB)

• NREL/EPRI: Current Utility Screening Practices, Technical Tools, Impact Studies, and Mitigation Strategies for Interconnecting PV on the Electric Distribution Systems Final Report. May 2013.  PDF (261 KB)

• Final project webinar slide deck [PDF]
• Webinar recording
  

• Task 6 Update Presentation: PV Hosting Capacity Analysis of PG&E Feeders. Oct 7, 2014. PDF (3 MB)
  

• Task 6 Update Presentation: PV Hosting Capacity Analysis of SDG&E Feeders. Oct 21, 2014. PDF (3.5 MB)

• SolarForum 2013 Presentation: "Alternative Screening Methods: PV Hosting Capacity in Distribution Systems." Smith, J. Electric Power Research Institute. PDF (1.48 MB)

• Initial Project Presentation. Aug 9, 2012. PDF

The EPRI team has collected feeder characteristic data for three California utilities. These data are summarized and described in the following documents:

• Utility 1: PDF (363 KB)
• Utility 2: PDF (300 KB)
• Utility 3: PDF (553 KB)

The EPRI team has also collected high-resolution time-series solar irradiance data from 20 monitoring systems installed across selected feeders. The monitoring units include an ac power meter to measure PV system output (real and reactive power, voltages, and currents) and a pyranometer to measure plane-of-array solar irradiance. Data were recorded at 1-second intervals. These data are summarized and described in the following documents:

• Summary of data collection results. 07-24-2015: PDF (5.5 MB)
• PV Data Information Jan-Jun 2014 and 2015: Excel (6 KB)
• PV Data Information Jul-Dec 2015
  • 1-minute: Excel (21.5 MB)
  • 15-minute: Excel (1.4 MB)

HOW TO REQUEST DATA
To obtain a CSV file with the raw data described in the above PDFs, please contact the grant manager William Marin (William.Marin @ Itron.com).