This paper describes a workflow for implementing and verifying transition control in an industrial hybrid microgrid (diesel–PV–BESS) with two microgrids coupled by a normally-open tie switch and interfaced to upstream networks through two primary substations. Each substation hosts a microgrid controller and a grid-forming BESS at the PCC; a supervisory layer issues operating commands and collects measurements for verification. The workflow is structured using the IEC TS 62898 series for microgrid project guidance and operation/control context and uses IEEE 2030.7/2030.8 as a controller-function taxonomy and a verification/test structure.

The workflow makes transition functions explicit as state-machine sequences, including breaker actions and setpoint/mode sequencing, and verifies them through a fixed scenario-based test suite with metric-based evaluation. It comprises requirements capture with standards mapping and voltage/frequency deviation envelopes used as pass/fail gates, controller decomposition into dispatch and transition functions, state-machine design for transition sequencing, reference generation for BESS setpoints (P/Q/V/f) and mode control, scenario execution, and verification using voltage/frequency envelopes and power-quality indicators with event-oriented logging aligned with IEEE 2030.8 monitoring categories. Modular, parameterizable DER unit models are used for PV, BESS, and diesel; each unit encapsulates plant dynamics together with its low-level control (and interface where applicable), allowing ratings and operating constraints to be changed without restructuring the supervisory transition logic.

Five scenarios are executed to exercise transition functions: planned islanding with ramp-down of grid power exchange prior to breaker opening, resynchronization using voltage/frequency/phase alignment prior to reconnection, black start of each microgrid with staged energization and load pick-up, and a disturbance scenario with three-phase-to-ground fault emulation followed by operational reconfiguration (islanding and tie-switch closure). Outputs include pass/fail evaluation against configured voltage/frequency envelopes, summary statistics of max/min deviations across cases, and power-quality checks including THD at PCC and load together with load-voltage deviation limits, aggregated into a verification summary package (metrics, event logs, key waveforms, and test results). Techno-economic sizing and detailed protection coordination are treated as separate workflows and are not within scope.