What is a Microgrid?

A microgrid consists of a group of generators and loads that:

  1. Allow smooth renewable energy integration
  2. Act as a single controllable electrical system
  3. Can operate grid-connected or islanded (during blackouts)

The University of St. Thomas Microgrid consists of the following energy assets:

  • Xcel Grid-Tie 13.8 kV
  • Substation
  • Substation Transformer 13.8 kV to 480 V
  • Switchgear 480 VAC Bus bars
  • Relays & Protection System SEL 451s and RTAC's
  • 48 kWdc Solar PV
  • 50 kW Diesel Genset
  • Battery Bank
    • 4 parallel strings
    • each string has 40 G200EP VRLA batteries
    • DC Voltage: 480-550V
  • Power Hardware in the Loop
    • OPAL RT OP4510 Real time simulator
    • Ametek MX-30 30 KVA power amplifier
    • Capable of emulating different sources/loads
    • Models can be implemented in Matlab/Simulink or HYPERSIM
  • Computer Controlled Load Bank 320 kVA 0.8 Power Factor
  • Microgrid Controller
    • Based on CSEISMIC developed by Oak Ridge National Laboratory
    • Amzur Technologies porting it to Sunspec model to monitor/control the microgrid
  • Third-party Testing
    • Equipment can be tested in grid-connected and/or island mode
    • Many combinations of sources/loads are possible given the flexibility of the microgrid