High Voltage Subsea Pump – A Low Cost Subsea Boosting Enabler

摘要

In a cost constrained scenario, technology driven solutions aiming at CAPEX reductions are crucial tornmake Subsea Processing (SSP) projects economically attractive. Subsea Processing encompasses three mainrnfields: (i) Subsea Gas or Liquid Separation, (ii) Subsea Compression and (iii) Subsea Boosting - Multiphasernor Water. Despite the fact that Boosting is a SSP discipline in itself, both Separation and Compression willrnalso rely on subsea pumps to support the process.rnAlthough subsea boosting technology is available and has been successfully deployed in several projects,rnhigh cost of system infrastructure is still a barrier for a broader technology adoption. Typically, a highrnboost subsea pumping system will require both topside and subsea infrastructure. Topsides, at the floatingrnproduction unit, a subsea pump will require electric power, a variable frequency drive (VFD) to controlrnmotor speed, and a hydraulic power unit (HPU) to supply subsea barrier fluid to the motor (except for ESPs).rnSubsea, a pump module, power connections and a high voltage umbilical are necessary pieces of equipmentrnwithout which the pump cannot be powered or installed. Aiming to reduce subsea umbilical cross-sectionrnand consequently overall system cost, operators have collaborated to develop a high(er) voltage subsearnmotor. Currently, existing subsea motors are powered with voltages ranging from 4.16 kV to 6.6 kV. Forrnumbilical power dissipation, higher voltage yields a square-law reduction effect. Since ampacity (amountrnof electric current a conductor can carry) is a function of to the amount of copper, lower amps translate intornless copper. The program scope comprises the design, components qualification and prototype build of arnpermanent magnet subsea motor to operate at 13.6 kV. Beta prototype design and ratings were based on arnexisting 3.2 MW Permanent Magnet Motor (PMM).