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Offshore jack up rig – Rowan Gorilla VI, Norway

When an old oil rig experiences a retrofit, there can often be increased power quality requirements due to the sensitivity of modern, upgraded equipment. This was the case with the offshore jackup rig, Rowan Gorilla VI.

Minke Field 2007
Rowan Gorilla VI


Because this Rowan rig is based in the North Sea off the coast of Norway, it is subject to class requirements mandated by Det Norske Veritas (DNV). In this instance, DNV required the Rowan Gorilla VI to exhibit a maximum of 8% voltage THD (total harmonic distortion) throughout all operating conditions.

Also, it is especially important in the offshore industry to save footprint. Rowan needed a solution that would meet the DNV voltage requirements while being efficient with space and weight.

Rowan Gorilla VI


After an initial assessment for the right solution, three ADF P300 units were shipped to the rig in Rotterdam for installation in September 2013. Rowan Gorilla VI began operating in October 2014 and continues to be operational today.


It is extremely important to meet regulatory standards in the offshore industry, and with ADF Power Tuning, Rowan Gorilla VI not only meets today’s standards, it goes beyond that. According to earlier simulations by Comsys, uncompensated levels for voltage THD reached around 13%. With ADF, Rowan Gorilla VI now shows voltage THD levels less than 8% and individual voltage harmonics at less than 5% – numbers well within the DNV mandate.

As an added benefit, ADF is a super compact solution, ensuring efficient use of space and minimized weight.

Installing ADF
ADF P300 installation