Distributed Generation Interconnection


Exponential Engineering Company has significant application experience in specifying, designing, applying, and obtaining approval for generation interconnections for cogeneration, net export, no intentional export, backup power, and emergency power. We provide recommendations for new interconnection requirements for municipal utilities and REA's.

Our design work includes sizing of generator neutral grounding systems, from solid ground to low or high resistance to reactive grounding. EEC participates on the IEEE P1547.2 Working Group for the Application Guide to the Generation Interconnection Standard.

  • California Rule 21 interconnections
  • Negotiation and follow-through between utilities and generating customers
  • Relay recommendations and settings, including submittals for approval by utilities
  • Operating procedures
  • Model and analyze generator contributions to utility system faults


A typical Generation Interconnection Project will consist of the following scope of work:

  • Investigate local utility standards for interconnection and establish utility requirements
  • Perform interconnection studies and fault studies
  • Calculate a complete set of generator and interconnection relay settings, including curves, documented calculations, and providing settings for direct download to relays via manufacturer's software
  • Settings for bus differential, bus synchronism check, and feeder relays as required
  • Size generator neutral ground as required