Microgrid Controller

Overview

A microgrid is a patch of the electrical grid that can stand on its own, solar panels, a battery, maybe a generator, and the loads they serve, connected to the main grid most of the time but able to disconnect and run as an island when the grid fails. None of that happens by itself. The microgrid controller is the conductor: it decides moment to moment which sources supply the load, holds voltage and frequency steady, and, when the grid goes down, cleanly detaches the site and keeps it powered. It is built as a rack of cooperating modules rather than a single box, so a site can scale its I/O and communications to match.

How it works

The brain is the Controller Boards stack, where a SoC runs the dispatch and optimisation logic and a real-time MCU runs the fast control loops that actually hold the island stable. It reaches the physical plant through the I/O Modules, which digitise field sensors and drive output relays, and through the Communication Gateway, which speaks Modbus, IEC 61850 and DNP3 so the controller can talk to inverters, meters and switchgear from many vendors.

Knowing the state of the grid depends on the Metering & Sensors section: power-quality meters fed by current and voltage transformers report exactly what each feeder is carrying. When something goes wrong, the Protection Relays relays detect over-current, voltage excursions or an islanding condition and trip the Breakers & Busbars stage, whose motorised breakers and busbars are the muscle the controller commands to reconfigure the grid.

An operator watches and overrides all of this from the Operator HMI touchscreen, which renders the one-line diagram and the live alarms. The electronics are fed by the Power Supply, and a Control-Power UPS of lithium cells with their own BMS keeps the controller and its protection alive through the very power interruptions it exists to manage, all packaged in the Cabinet.