This simulator models a balanced 480 V, 60 Hz microgrid with solar generation, a 100 kW / 200 kWh grid-forming battery, an 80 kW backup generator, critical and flexible loads, and a point of common coupling (PCC) to the utility. Trigger a utility outage, keep the island powered, and practice bringing it back into synchronism before reconnecting.
• A real-time 3D scene with six tappable, labeled components — utility & PCC, solar array, battery energy storage, backup generator, critical loads and flexible loads — each showing live status and role description, with a reset-camera view and a hide/show-labels toggle. • Grid & dispatch controls: utility outage, open PCC, restore utility, synchronize, close PCC, start/stop generator, and shed/restore flexible load, plus a battery grid-forming enable checkbox and an automatic priority load-shedding checkbox. • Environment & demand sliders: available solar (0–120 kW), critical load (10–150 kW), flexible load (0–100 kW), and battery state of charge (10–95%, an experiment-setup override that is logged when changed). • Time controls: pause/resume, step 0.1 s, reset lab, and a playback speed selector (1x, 10x, 60x). • A live frequency-response chart covering the last 60 simulated seconds, a real-time power-balance readout (solar + generator + battery + utility import versus load, plus delivered and unserved energy), and a synchronization-status readout (Δfrequency, Δphase, bus voltage and sync dwell time toward the 2-second closing requirement). • An Experiments tab with 6 guided experiments (seamless island, cloud & generator response, no grid-forming source, priority load shedding, capacity overload, resynchronize) that each set up a specific scenario with one click. • A Learn & test tab explaining what maintains the island, the model's equations and boundary, real-world microgrid controller use, and a 3-question knowledge check. • A sequence-of-events log recording every state transition, control action and automatic protective response with a timestamp.
Opening the PCC isolates the microgrid from the utility; at that instant, at least one local source must establish voltage and frequency, or the bus de-energizes entirely. In this model the battery inverter can grid-form (when its grid-forming toggle is enabled and state of charge is above 10%), and the backup generator can also establish a reference once started — but the 80 kW generator takes an explicit 8-second start delay and ramps at only 20 kW/s, so short-term deficits are covered by the battery's near-instant response, with frequency computed from a reduced-order 0.6-second time-constant relaxation toward 60 + 0.045×ΔP Hz rather than an electromagnetic transient solution.
Reconnecting requires more than the utility simply coming back: Restore utility only clears the outage flag, it does not close the PCC. You must explicitly enable Synchronize and wait for the controller to bring the island's frequency and phase into alignment — closing requires the utility available, a live island, |Δf| < 0.1 Hz, |ΔV| < 5%, and |Δphase| < 10° sustained for a full 2 seconds. The simulator enforces this deliberately: a mismatched reconnection is exactly the failure mode the interlock exists to prevent, and "resynchronize" is one of the built-in guided experiments.
The event log and power-balance readout make every automatic protective action visible and attributable: automatic priority load shedding disconnects flexible load first, either from a low state of charge (below 20%) or when demand outstrips available capacity, and separately an underfrequency shed can trigger at 57 Hz if the primary shedding hasn't already acted. Both are distinguishable in the log by their trigger condition, not just their effect.
This is a deterministic, balanced, reduced-order real-power teaching model. It does not solve AC power flow, reactive power, fault currents or electromagnetic transients, and it is not certified protection-coordination software. Voltage sag is an illustrative deficit indicator rather than a solved voltage profile, component capacities and synchronization thresholds are teaching presets rather than installation settings, and demand is treated as constant real power on a balanced three-phase bus.
Opening the point of common coupling isolates the microgrid from the utility, and the island bus only stays energized if at least one local source is grid-forming. If the battery's grid-forming toggle is disabled and the generator has not been started, no source establishes voltage or frequency, and the bus goes dead — this is exactly what the "no grid-forming source" guided experiment demonstrates.
Restore utility only clears the outage condition; reconnecting a live island to the grid requires explicit synchronization. You must enable Synchronize and wait until |Δf| < 0.1 Hz, |ΔV| < 5% and |Δphase| < 10° hold for a full 2 seconds before Close PCC is allowed — this interlock exists specifically to prevent an out-of-sync reconnection.
Yes. Priority load shedding (when enabled) sheds flexible load when battery state of charge drops below 20% or when demand exceeds available capacity. Separately, an underfrequency shed can trigger if island frequency falls below 57 Hz and priority shedding hasn't already acted. Both appear as distinct, timestamped entries in the event log.
It is a deterministic, balanced, reduced-order real-power teaching model. It does not solve AC power flow, reactive power, fault currents or electromagnetic transients, and component capacities and synchronization thresholds are teaching presets rather than installation-grade settings. Frequency response uses a simplified 0.6-second relaxation, not a full inertial/governor simulation.