The use of subsea processing equipment, which maintains, increases and speeds up oil and gas production, is now more and more widespread on offshore subsea oil and gas field developments. Further, there is a strong drive for electrification of offshore fields, both subsea and topside installations, to lower emissions. To meet the technical challenges of these developments, subsea transmission, distribution and conversion electrical equipment are developed through the ABB Subsea Power JIP where ABB, Equinor, Chevron and Total are partners. In 2013, ABB and its Joint Industrial Partners, Equinor, Total and Chevron, began an expansive project to design and test a complete subsea electrification solution for the oil and gas industry. To enable operations at remote locations in ultra-deep waters ABB developed modular equipment - components and assemblies - that integrate to form a subsea electrification system. The system consists of variable speed drives (VSDs), switchgear and a protection and control system for the transmission, distribution and conversion of power to subsea pumps and gas compressors at a peak capacity of 100 MW to water depths up to 3,000 meters; and with transmission distances up to 600km with lifetime requirements for up to 30 years. Topside area is freed, power supply demands and greenhouse gas emissions are reduced. Figure 1 illustrates atypical subsea processing facility.Existing offshore fields are depleting fast and the new coming fields are not easy to develop due to their reduced size or dispersed locations. Fields may also yield more challenging fluids. Therefore, new ways for economical subsea processing are being developed for subsea separation, electrical heating, subsea compression and multiphase pumping on the sea floor, which speeds up production and as well increasing its recoverable volume. All these solutions require power at the seafloor to drive the respective pumps and compressors.Improving energy efficiency and reducing CO_2 intensity associated with production of hydro carbons are amongst the top priorities as of today. The subsea electrification technology can be an enabler for supplying subsea boosting with power from shore. Also, subsea compression as a standalone technology requires significantly less energy compared to platform compression. The closer the compression is located to the source, the higher the efficiency. The conversion and distribution technology may in many cases be an enabler for subsea compression and pumping.By placing the VSDs subsea, the electrical transmission will operate at a fixed frequency of 50 or 60 Hz, compared to a variable, and higher, frequency in case of topside/onshore VSDs. A case study for a specific use candidate showed that the electrical transmission losses can be reduced up to 50% by using subsea VSDs. Subsea power distribution and conversion can play an important role in realizing un-manned facilities, both for all subsea solutions and in combination with un-manned topside installations. Reduction in manning/personnel and utilities required for topside offshore installation reduces the associated emissions from the oil and gas production.Adopting a pragmatic step-wise approach to equipment design ABB successfully ran simulations, laboratory and field tests to ensure every component, sub-assembly and assembly met qualifications according to Technical Readiness Level (TRL) stages defined in DNV RP-A203 and API 17F Standard for Subsea Production Systems. Satisfied with individual device results, shallow water tests (SWT) were conducted: a prototype of a medium-voltage VSD, was operated in a harbour test site impeccably for over lOOOhrs. In June 2019, a second, now 3000h SWT of a prototype of the entire electrification system, two VSDs in parallel configuration with switchgear, controls and auxiliary, was initiated. Results of this test and all previous qualification accomplishments will ensure system reliability under harsh subsea conditions. Upon completion, the oil and gas industry will know that this electrification solution is ready-for-use in the remote subsea environment. This paper will share the subsea journey and the exiting outcome of the 3000h SWT for the entire system. Figure 2 shows one of the VSDs and the switchgear being lowered into the water ready to start the 3000h test at the ABB test site in Vaasa, Finland.
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