Aspin Kemp & Associates recently demonstrated a successful Short Circuit Test on the DP3 Main Power and Propulsion Plant on the Deepwater Conqueror. These videos show the last 100ms of the test:
The Short Circuit Test takes only seconds to witness but proves that the AKA DP3 Main Power and Propulsion Plant is immune to major power disturbances, such as a short circuit on the main bus. All thrusters and distribution systems remain in service, and DP station keeping remains stable and is not influenced by the event.
This AKA system and testing delivers far beyond the obvious successful response of the plant to that specific short circuit. AKA’s built in data logging system, and the connected external electrical recording equipment, records the exact currents, voltages, and breaker status on a high resolution time-line. The recording of this high energy high and speed short circuit prove that the accuracy, transient, and long term response is as predicted by the AKA mathematical model.
The test also:
- Proves the effectiveness of AKA’s high speed fault detection programming for rapid variations in voltage and current;
- Critically proves the longer term effectiveness of AKA’s diesel speed and voltage regulator programming; and
- Proves the effectiveness of both the primary and back up protection.
The accurate correlation between the measured response and AKA’s predicted response is the basis of both the owner’s and the Class authority’s approval of vessel operation. This is carried out with a closed main power bus while classed as a DP3 vessel. Without the proven math model that is used to accurately predict any possible power plant fault, fault tolerance with closed bus operation could never be demonstrated and approval never obtained.
Among the many design features that ensure predictable and successful performance one of the strongest is AKA’s Cascade Injection Testing. This simple and autonomous test proves protection on all plant protection circuits so that response of all generators is proven. This goes beyond simply exposing the generators to a short circuit.
The AKA design was the first system, by special consideration and testing, to be approved by DNV for DP3 closed bus operation. The AKA analysis, testing, and special DNV approval for the Deepwater Asgard and the Deepwater Invictus was the basis for the DNV revision of rules that now allow, with completion of similar analysis and testing, for formal certification of DP3 fault tolerance with a closed main bus.
AKA’s design has been both analytically and practically proven to the satisfaction of DNV and ABS on many vessels. This design forms a significant element in the critical vessel operations risk management strategy.