Updating Interconnection Screens for PV System Integration

Updating Interconnection

Author:  Coddington, Michael | Mather, Barry | Kroposki, Benjamin |Lynn, Kevin | Razon, Alvin | Ellis, Abraham | Hill, Roger | Key, Tom |Nicole, Kristen | Smith, Jeff

Organization:  US Department of Energy | Sandia National Laboratory |National Renewable Energy Laboratory | Electric Power Research Institute

Report Date: 2012



This government study evaluates the origins and usefulness of the capacity penetration limits (or “screens”) used to fast track interconnection processes, offers short-term solutions to allow faster interconnection for PV systems, and recommends long term solutions for increasing PV deployment levels safely and reliably while reducing or eliminating capacity penetration limits set in interconnection rules. 

Key Take-Aways: 

  • Short term approaches to streamlining interconnection standards include utilizing PV specific screening criteria that utilize minimum daytime load versus the absolute minimum load or percentage of peak load at the circuit; applying additional limits that evaluate potential voltage problems separate of penetration levels; and including penetration levels in specific areas and zones based on substation location, circuit design, and existing DG.
  • Mid-term and long-term solutions require close cooperation between stakeholders involved and determining how much solar PV can be deployed on a circuit while focusing on safety, reliability, and cost. 

Key Facts: 

  • Interconnection standards should be streamlined as much as possible, across state jurisdictions and utility territories, to avoid unnecessary interconnection studies, costs and delays for increasing levels of PV deployment.
  • Most interconnection procedures allow for expedited interconnection without additional technical studies if the proposed interconnection passes a set of technical screens intended to support voltage control, unintentional islanding, and protection coordination.
  • PV interconnection requests are screened at a 15% of circuit peak load threshold, and PV projects above this threshold capacity trigger additional studies to analyze system updates needed to incorporate the PV installation. In many cases when PV interconnection requests trigger the additional review, the additional review does not identify necessary system upgrades that are implied. 

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