Case study
Ocean Garnet: power management upgrade
From manual DEIF GPU controllers to DEIF iE250 power control for DP2 readiness.
Hogger Offshore · April 2025
The requirement
Generator start/stop, load balancing and breaker operations required continuous manual intervention. The vessel needed split-bus power control and automatic blackout recovery.
Engineering scope
Assessment, electrical drawings, panel modifications, controller configuration, redundant communications, HMI and alarm interfaces, followed by FAT, harbour tests and sea trials.
Systems & technology
DEIF iE250 controllers, redundant Ethernet, generator and bus-tie breaker logic, shaft-generator and stern-thruster changeover.
Documented outcome
The project report records blackout recovery in 6–8 seconds during testing, balanced generator load sharing and validated split-bus operation. These are reported project results, not a general performance guarantee.
Control architecture
Each generator and the bus-tie breaker has a dedicated DEIF iE250 controller linked over redundant Ethernet.
The split-bus arrangement uses a normally open tie-breaker for segregated power paths.
Controllers measure voltage, current, power factor, frequency and load, and handle breaker status, commands and interlocks.
Functions delivered
Load-based generator start/stop, synchronisation and active/reactive load sharing.
Priority-generator restart and reconnection of essential loads after a blackout.
Stern-thruster supply changeover from Shaft Generator 1 to Shaft Generator 2 under a trip condition.
Manual overrides, safety interlocks, HMI alarm logging and event history.
Installation and testing
Existing wiring and control philosophy were assessed before new drawings, I/O schedules and communications layouts were prepared.
Panels were modified and controllers configured, with every I/O channel, interlock and communication link checked.
Factory tests simulated generator, load-sharing and blackout conditions. Harbour and sea trials checked split-bus behaviour, changeovers, alarms and operator controls.
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