WO2013077744A1 - System for very long subsea step-out transmission of electric dc power - Google Patents
System for very long subsea step-out transmission of electric dc power Download PDFInfo
- Publication number
- WO2013077744A1 WO2013077744A1 PCT/NO2012/050233 NO2012050233W WO2013077744A1 WO 2013077744 A1 WO2013077744 A1 WO 2013077744A1 NO 2012050233 W NO2012050233 W NO 2012050233W WO 2013077744 A1 WO2013077744 A1 WO 2013077744A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- subsea
- hvdc
- motor
- loads
- cable
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
Definitions
- the present invention relates to equipment located subsea far away from onshore or topside locations, particularly equipment for petroleum fluid pressure boosting requiring high alternating current electric power level or high direct current electric power level, but also other subsea equipment of various types.
- the problems are enhanced at increasing power level, therefore operation of subsea equipment requiring a high level of electric power, such as subsea pressure boosting equipment like subsea compressors, subsea multiphase pumps and subsea pumps, is most challenging.
- the problems increase with increasing subsea step out cable length, increasing voltage, increasing frequency and increasing capacitance. So far subsea step out lengths of about 40 km is feasible for power level of about 20 MW, transmission frequency of 100-200 Hz and a voltage level of about 100 kV, feasible for operation of subsea compressors without too high ohmic losses or electrical instability.
- the patent applications NO 201 1 1233 and PCT/EP201 1/065797 both in the name of the applicant, provides technology that can work at subsea step out lengths up to about 150- 200 km for subsea high power loads like compressors and multiphase pumps. This is achieved by comparatively low transmission frequency, about 50-60 Hz and lower, and step-up to the actual operating frequency close to the subsea equipment.
- the technology of NO 201 1 1233 and PCT/EP201 1/065797 involves that the subsea power electronic control installation, the subsea VSD, which is big, expensive and in practice unreliable, is replaced by other technology.
- the maximum achievable subsea step out length is about 150 km.
- VSD-variable speed drive also called variable frequency drive, VFD, and other terms
- VFD variable frequency drive
- the invention provides a system for operation of electric power subsea loads supplied through a subsea step out cable, particularly high electric power subsea loads, distinctive in that the system comprises a high voltage direct current (HVDC) transmission subsea step out cable, the cable is connected to a HVDC source in a near end and to a HVDC motor in a far subsea end.
- HVDC high voltage direct current
- the loads comprises high electric power loads, as defined below, and the step out length can be or is over 40 km.
- the HVDC motor is a part of a subsea motor generator set or is coupled to a subsea pump or a subsea compressor.
- HVDC is in this context DC voltage above 2 kV and high electric power loads are in this context loads of at least 1 MW maximum effect, such as effect in the range 5-25 MW.
- the source is usually a topside or onshore source, however, the source can also be a subsea source.
- the far end connected HVDC motor can be rated at lower voltage than the HVDC source since losses will occur and start up can be arranged always to be soft, controlled from the near end for example by an adjustable resistor.
- the HVDC step out cable and HVDC subsea motor of the system of the invention are rated to operate at a maximum voltage of 2-250 kV, such as 20-150 kV, at 1 , MW, 5, MW, 10 MW, 20 MW, 40 MW or even higher effect, and the subsea step out distance can be above 40 km, such as 50, 100, 150, 200, 400, 600 , 800 or 1600 km or above.
- Prior art AC power supply is limited to about 40 km subsea step out length at operation frequency for high power loads such as subsea compressors and pumps.
- the present invention is particularly relevant for subsea step out lengths above 40 km, for which no publicly known solution exist without a subsea VSD, and even more relevant for subsea step out lengths above 150 km where solutions based on subsea VSD are questionable.
- the HVDC motor is preferably connected to a subsea compressor or pump, directly on the same shaft or by a coupling or a gear coupling such as a step up device, preferably a magnetic step up gear, or the HVDC motor is a part of a motor-generator set connected to a further load such as an AC subsea compressor or pump motor.
- the HVDC motor is part of a motor-generator set comprising a common shaft, for example an AC generator producing 6.6 kV or 1 1 kV power with a frequency of 150 Hz, the produced voltage from the generator is the voltage required by the electric loads (AC motors, UPS, control systems) that the generator supplies.
- the HVDC motor is part of a DC motor-generator set.
- the HVDC motor comprises stator windings with insulated high voltage cables instead of the traditional stator bars.
- This allows increasing the voltage to HVDC level that is above 2 kV, such as 10 kV, more preferably 15 kV, even more preferably above 20 kV such as 120 kV.
- insulated windings for power level up to at least 150 kV, i.e. Motorformer of ABB.
- the load is preferably arranged in a gas filled pressure housing or a pressure compensated oil filled housing. Loads with active magnetic bearings in a gas filled pressure housing provides high efficiency, and represents a preferable embodiment.
- the system comprises a control at a near end topsides or onshore.
- This can have many embodiments, of which the simplest is a variable resistor device useful for controlling the speed of the connected loads at the near end from topsides or onshore.
- the system of the invention comprises a local control device at each subsea load.
- the combined high voltage DC motor and an AC or DC generator on the same shaft is one such local control device, in the context of this invention called "DC Transformer".
- the speed of the DC motor can be regulated by known methods (ref. NO 201 1 1235), and because the generator speed will vary accordingly and by doing this the subsea DC Transformer can also have the function similar to that of a subsea VSD. If one DC Transformer is arranged per compressor motor, the speed of each compressor can be varied individually.
- a DC transformer with DC generator can be used to transform the DC voltage level down to a lower level more feasible for a further DC load, providing higher amperage, and similarly for an AC load if the generator is an AC generator.
- the system of the invention comprises a single or two or more in substance parallel HVDC subsea step out cables, each cable is connected to one or a number of loads, the cables and loads are dimensioned so that at the maximum workload of the loads the far end cable voltage equals the maximum voltage level allowable for the loads whilst the near cable end voltages equal the far cable end voltage plus ohmic loss in the respective cables and in the near end the respective cables comprises a means for voltage control, such as an adjustable resistor or other known devices.
- DC loads of lower voltage rating than the HVDC subsea step out cable can be used.
- the near end voltage of the source can be adjusted up to higher voltage than allowable for the loads when operating the HVDC motor loads at full or high speed. If one or more loads are not in operation, the voltage can be adjusted down at the near cable end so as not to exceed the maximum allowable DC motor voltage at the far end of the step out cable.
- the system comprises one or more of the loads: a subsea
- a compressor a subsea multiphase pump, a subsea pump, a subsea control system, a subsea heat tracing system, a subsea valve actuator, a subsea processing facility, a subsea uninterruptible power supply, a subsea DC transformer and a subsea inverter.
- the invention also provides a method of arranging a system for operation of high electric power subsea loads, distinctive by arranging a subsea electric HVDC power step out cable, connecting a HVDC source at a near end and a subsea HVDC motor at a far subsea end.
- the method preferably comprises to operate the HVDC step out cable and HVDC subsea motor of the system of the invention, up to a maximum voltage of 2-250 kV, such as 20-150 kV, at 40 MW or higher effect, at a subsea step out distance that can have length above 40 km, such as 50, 100, 150, 200, 400, 600, 800 or 1600 km.
- the HVDC motor is connected to a subsea compressor or pump, directly on the same shaft or by a gear coupling such as a step up device, or the HVDC motor is a part of a motor- generator set connected to a further load such as an AC subsea compressor or pump motor.
- the invention also provides use of a system of the invention, for operating high power level subsea loads at subsea step out distances that can be longer than 40 km of length.
- FIG. 1 illustrating a system of the invention
- FIG. 1 illustrating an embodiment of a system 4 of the invention, more specifically a surface HVDC source 1 , a subsea HVDC step out cable 2 of 50 kV, at power level of 40 MW or higher, the cable subsea step out length is above 150 km.
- the cable is connected directly to four subsea loads 3 at the cable far end.
- the system 4 in the illustrated embodiment comprises the HVDC source 1 , the HVDC subsea step out cable 2 and the loads 3 which all includes HVDC motors connected to the step out cable.
- the loads are DC high voltage compressor motors, each of 10 MW power level. 6,6 kV voltage, all motors are controllable as a group from the near end by a variable resistor or other known means, such as an electronic speed controller.
- the speed of the motor is conveniently controlled up and down by varying the DC voltage from surface up and down. If there are more motors, the speed level of all motors can be varied by varying the surface voltage, and additionally the speed of each motor can be controlled by local individual speed control of each motor by known method, e.g. voltage control to the individual motor by variable resistor, rheostats, or electronic speed control, by known methods for parallel, series or compound DC motors.
- the high voltage DC motors can be of the known traditional type, but modified with insulated stator windings, such as stators wound with high voltage DC cable with XLPE (cross linked polyethylene) insulation or other feasible insulation, and optional additional cooling, and optionally the motors can have permanent magnet rotor.
- insulated stator windings such as stators wound with high voltage DC cable with XLPE (cross linked polyethylene) insulation or other feasible insulation, and optional additional cooling, and optionally the motors can have permanent magnet rotor.
- FIG. 2 illustrates another embodiment of a system 4 of the invention, with loads 5 as four DC transformers.
- loads 5 as four DC transformers.
- a HVDC motor drives a 6,6 kV AC generator arranged on the same shaft, the AC generator is connected to an AC compressor motor 6 of 10 MW and 6,6 kV.
- the invention makes it possible to transmit electric power over very long distances. There will in principle not be any technical limitation of stable subsea power transmission length, however in practice a possible limitation may be a practical or economical copper cross section area for control of ohmic power loss.
- the source can be a HVDC source in northern Norway and the loads can be subsea compressors and pumps arranged subsea at the seabed at the North Pole, under the arctic ice cap, supplied by a HVDC cable connected to the source.
- the system of the invention may include any feature as described or illustrated in this document, in any operative combination, each operative combination is an embodiment of the invention.
- the methods of the invention may include any feature or step as described or illustrated in this document, in any operative combination, each operative combination is an embodiment of the invention.
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Laying Of Electric Cables Or Lines Outside (AREA)
- Control Of Multiple Motors (AREA)
- Direct Current Feeding And Distribution (AREA)
- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
- Other Liquid Machine Or Engine Such As Wave Power Use (AREA)
- Control Of Ac Motors In General (AREA)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2012341141A AU2012341141B2 (en) | 2011-11-22 | 2012-11-22 | System for very long subsea step-out transmission of electric DC power |
BR112014012092A BR112014012092A2 (en) | 2011-11-22 | 2012-11-23 | system for the transmission of markedly long-distance underwater power transmission ' |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NO20111612 | 2011-11-22 | ||
NO20111612A NO336604B1 (en) | 2011-11-22 | 2011-11-22 | System and method for operating underwater loads with electric power provided through an underwater HVDC outfitting cable |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2013077744A1 true WO2013077744A1 (en) | 2013-05-30 |
Family
ID=48470100
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/NO2012/050233 WO2013077744A1 (en) | 2011-11-22 | 2012-11-22 | System for very long subsea step-out transmission of electric dc power |
Country Status (4)
Country | Link |
---|---|
AU (1) | AU2012341141B2 (en) |
BR (1) | BR112014012092A2 (en) |
NO (1) | NO336604B1 (en) |
WO (1) | WO2013077744A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102015226640A1 (en) | 2015-12-23 | 2017-06-29 | Voith Patent Gmbh | Underwater propulsion unit |
US9951779B2 (en) | 2013-12-27 | 2018-04-24 | General Electric Company | Methods and systems for subsea boosting with direct current and alternating current power systems |
WO2020127339A1 (en) | 2018-12-18 | 2020-06-25 | Subsea 7 Norway As | Long-distance transmission of power underwater |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1997045919A2 (en) * | 1996-05-29 | 1997-12-04 | Asea Brown Boveri Ab | Rotating electric machines with magnetic circuit for high voltage and method for manufacturing the same |
US20090308656A1 (en) * | 2001-08-19 | 2009-12-17 | Chitwood James E | High power umbilicals for subterranean electric drilling machines and remotely operated vehicles |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2382600B (en) * | 2001-12-03 | 2005-05-11 | Abb Offshore Systems Ltd | Transmitting power to an underwater hydrocarbon production system |
EP2293407A1 (en) * | 2009-09-08 | 2011-03-09 | Converteam Technology Ltd | Power transmission and distribution systems |
US9181942B2 (en) * | 2010-04-08 | 2015-11-10 | Framo Engineering As | System and method for subsea production system control |
-
2011
- 2011-11-22 NO NO20111612A patent/NO336604B1/en not_active IP Right Cessation
-
2012
- 2012-11-22 AU AU2012341141A patent/AU2012341141B2/en not_active Expired - Fee Related
- 2012-11-22 WO PCT/NO2012/050233 patent/WO2013077744A1/en active Application Filing
- 2012-11-23 BR BR112014012092A patent/BR112014012092A2/en not_active IP Right Cessation
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1997045919A2 (en) * | 1996-05-29 | 1997-12-04 | Asea Brown Boveri Ab | Rotating electric machines with magnetic circuit for high voltage and method for manufacturing the same |
US20090308656A1 (en) * | 2001-08-19 | 2009-12-17 | Chitwood James E | High power umbilicals for subterranean electric drilling machines and remotely operated vehicles |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9951779B2 (en) | 2013-12-27 | 2018-04-24 | General Electric Company | Methods and systems for subsea boosting with direct current and alternating current power systems |
DE102015226640A1 (en) | 2015-12-23 | 2017-06-29 | Voith Patent Gmbh | Underwater propulsion unit |
WO2017108375A1 (en) | 2015-12-23 | 2017-06-29 | Voith Patent Gmbh | Underwater drive unit |
WO2020127339A1 (en) | 2018-12-18 | 2020-06-25 | Subsea 7 Norway As | Long-distance transmission of power underwater |
Also Published As
Publication number | Publication date |
---|---|
BR112014012092A2 (en) | 2017-05-30 |
AU2012341141B2 (en) | 2017-04-13 |
NO336604B1 (en) | 2015-10-05 |
AU2012341141A1 (en) | 2014-05-08 |
NO20111612A1 (en) | 2013-05-23 |
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