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Microgrid Projects

NREL is providing microgrid testing services for the Sacramento Municipal Utility District and Portland General Electric.

Sacramento Municipal Utility District

Photo of SMUD microgrid equipment at NREL's DERTF

SMUD microgrid equipment at NREL's DERTF.
Photo by Connie Komomua, NREL

Sacramento Municipal Utility District (SMUD) is installing a microgrid at its headquarters in Sacramento, California. To support this important endeavor, NREL has completed testing of newly-developed microgrid switch technology from Cyberex, and two 100 kilowatt Tecogen combined heat and power modules with inverter and droop control at its Distributed Energy Resources Test Facility (DERTF). The testing was performed in compliance with Institute of Electrical and Electronics Engineers (IEEE)1547.1 and IEEE 1547.4 requirements, including:

  • Temperature stability
  • Response to abnormal voltage conditions
  • Response to abnormal frequency conditions
  • Synchronization
  • Interconnection integrity
  • Limitation of direct current injection for inverters without interconnection transformers
  • Unintentional islanding
  • Reverse power (for unintentional islanding)
  • Open phase
  • Reconnect following abnormal condition disconnect
  • Harmonics
  • Flicker (no test).

By working with NREL researchers, SMUD is fine-tuning its microgrid configurations for optimal performance.

Portland General Electric

NREL is providing thorough microgrid performance testing services on actual systems for Portland General Electric, a utility provider, based on IEEE 1547.1 and IEEE 1547.4 requirements. Successful testing reduces the risk of operational performance issues at the permanent site.

Testing services include the following:

  • Performance Testing
    Testing basic operational functions, operating modes and states, and inverter paralleling operation on power inverter, battery, and generators

  • Systems Integration and Transition Testing
    Ensuring systems work together, verifying that key system functions like picking up the load immediately after the grid disconnects work; testing key transitions between basic states; and ensuring proper sequencing of transitions from island mode to grid-connect mode without disturbances

  • Fault Testing
    Testing the fault contribution of the inverter to high and low impedance faults, and the inverter's interaction with typical lateral protection devices.