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Jack-up drilling plattform, South China Sea

Tam Dao 03 is a LETOURNEAU™ Super 116E jack-up drilling platform operating in the South Chinese Sea. Built according to DNV (Det Norske Veritas) standards, this MODU (mobile offshore drilling unit) comprises four generators, each 2150 kVA, which feed into a 600V bus. The main loads onboard Tam Dao 03 are the 10 large VFDs (Variable Frequency Drives) that regulate the rig’s heaviest activities, including the mud pumps, draw works, and top drive.

cong trinh gian khoan tam dao 03
Tam Dao 03 jack-up drilling plattform

Industry: Offshore Oil and Gas
Rig name: Tam Dao 03
Project partner: Danfoss Norway
Customer: Vietsovpetro
Timeline: 2010


Subject to DNV requirements, Tam Dao 03 must achieve a TVHD (Total Voltage Harmonic Distortion) of less than 8% under all operating conditions.

With the multiple generators and drives online, the electrical load is heavy and demanding — creating a need for a filter solution that will continuously track the load and adapt, in all operating conditions.


To compensate such a dynamic load, we looked to our powerhouse solution: the ADF P300.

Four, fully loaded, air-cooled ADF P300 units, rated for up to 690V

The ADF P300 units are connected directly on the 600V bus and configured in open loop (where the ADF units’ CTs read the load) into the rig’s existing infrastructure. Without the need for additional equipment or space, ADF contributes to a smaller sized, lighter, and less expensive installation compared to other filter technologies.

Tam Dao 03


The active filter technology onboard now ensures that Tam Dao 03 never exceeds more than 8% TVHD, no matter the operating conditions. In addition to the < 8% TVHD requirement, DNV also mandated Tam Dao 03 must have less than 5% on any individual voltage harmonic. Once up and running with ADF technology, during typical operation the 5th harmonic was less than 2% on the voltage. The results exceed the DNV requirements with a comfortable margin, and also ensure an added bonus of secure redundancy.