ABB has presented a new, compact, high-voltage direct current (HVDC) solution for offshore wind which is said to cut the weight and the volume of an offshore platform by more than half and eliminate the need for alternating current (AC) substation platforms.
ABB’s new HVDC solution eliminates the need for AC platforms since the wind turbine generators can now be connected directly to the HVDC platform via a 66 kV collection grid, the company said.
Eliminating the AC substation platform potentially increases the total weight saving further, up to a total of 70 percent compared to a conventional setup and reduces operational costs by removing the long-term maintenance of these stations, according to ABB.
The new HVDC concept is based upon a modular product structure. The optimized base-level platform contains everything needed for a fully operational HVDC platform but if for example, there is need for living quarters, a helipad, a more powerful crane or other options, the concept allows them to be added without designing and fabricating an entirely new platform from scratch, ABB said.
Each module needed can be produced individually, in parallel with others and in more diverse and smaller workshops, as opposed to the traditional fabrication of the entire topside platform in a dedicated yard.
This, according to ABB, greatly increases the number of suitable suppliers, which provides a more competitive environment and significantly reduces the risks inherent in all such mega projects.
As well as advantages in fabrication, there are also substantial transportation benefits. There are very few vessels capable of transporting and installing the largest platforms but, with half the weight and the flexibility to distribute the modules between cargo carriers, the new concept represents a step change in logistical management.
The savings in weight delivered by the new HVDC concept have been achieved by a substantial reduction in the HVDC hardware installed on the platform and extensive studies and tests helped point the way to reduce redundancy while maintaining the required high levels of availability in the system, according to ABB.