Solar-plus-storage microgrid and utility interconnection
Designed and interconnected a 1.2 MW solar array with a 600 kWh battery for a campus microgrid, with peak shaving, backup power and full IEEE 1547 utility compliance.
What we were engaged to build.
Actual ratings, devices and standards.
The service voltages, equipment ratings, protective functions and codes this project was built and tested against.
The specific electrical solutions we used.
How each design decision solved a real constraint on this project — from redundancy and coordination to protection and commissioning.
Microgrid controller with three modes
A single controller switches between peak shave, load follow and grid-backup, so the campus can cut demand charges in normal operation and island automatically when the grid drops.
Anti-islanding protection at the PCC
27/59/81/32/46 relays plus a reverse-power relay guarantee the inverter trips before the utility crew works a dead line, satisfying IEEE 1547 and CA Rule 21.
Bi-directional revenue metering
A bi-directional meter at the PCC records imports and exports separately, so the campus settles net exports under the utility tariff rather than losing them.
Seamless islanding and resync
On a utility outage the battery forms the island in milliseconds, holding the campus up; on return the controller resyncs and closes the breaker, reconnecting without a second outage.
From the build.
