Weighing-up the options
The HVDC substation required a footprint of 66m x 70m and used a conventional four-column semi-submersible design.
A stressed-skin topsides was designed, using the external skin and internal walls to provide strength and stiffness. This is more efficient than a conventional structure.
The HVAC substation design produced more challenges because of the small footprint and lighter weight.
Different options for the semi-submersible hull were considered and a novel deep-draught design was selected, giving low motions, and retaining the practicality of a shallow draught for transportation and maintenance.
By developing a braced topsides structure with transformers open to the elements, we were able to keep the topsides structure to a minimum.
Our work on these advanced concept designs will ensure we stay at the cutting edge of this rapidly developing field.