Subsea measurement and monitoring

• US 9,203,342 B2
• Filed: 10/08/2013
• Issued: 12/01/2015
• Est. Priority Date: 04/08/2011
• Status: Active Grant

• Current Assignee: ABB Schweiz AG (ABB Limited)
• Original Assignee: Abb As (ABB Limited)
• Inventors: Rongve, Knut, Wiik, Jan, Moen, Tor-Eivind, Hoosh, Behrooz-Moghimian
• Primary Examiner(s): Ro, Bentsu
• Application Number:
  US14/048,942
• Publication Number:
  US 20140035504A1
• Time in Patent Office: 784 Days
• Field of Search: 318/16, 318/434, 318/474, 318/490, 318/565, 388/909
• US Class Current: 1/1
• CPC Class Codes: G01R 31/28 Testing of electronic circuits, e.g. by signal tracer EMC, EMP or similar testing of electronic circuits G01R31/002; testing for short-circuits, discontinuities, leakage or incorrect line connection G01R31/50; checking computers or computer components G06F11/00; checking static stores for correct operation G11C29/00 ; testing receivers or transmitters of transmission systems H04B17/00
• CPC Class Codes: G05B 23/0235 based on a comparison with predetermined threshold or range, e.g. "classical methods", carried out during normal operation; threshold adaptation or choice; when or how to compare with the threshold
• CPC Class Codes: H02P 29/02 Providing protection against overload without automatic interruption of supply protection against faults of stepper motors H02P8/36
• CPC Class Codes: H02P 31/00 Arrangements for regulating or controlling electric motors not provided for in groups H02P1/00 - H02P5/00, H02P7/00 or H02P21/00 - H02P29/00

Abstract

A method for monitoring at least one subsea electric machine supplied by a system for electric power transmission. The system has a power supply, a controller and an AC power line connecting the at least one machine with the power supply. The method includes the steps of: receiving at the controller, high speed data from at least one subsea sensor arranged between the subsea side of the AC power line and the at least one subsea electric machine, wherein the high speed data includes measurements of an electrical parameter for the at least one machine; and comparing the one or more measurements to a predetermined value. A system for electric power transmission arranged for operating at least one subsea load or electric machine is also described.

Claims

1. A method for monitoring at least one subsea electric machine supplied by a system for electric power transmission, the system having power supply, a controller and an AC power line connecting the at least one machine with the power supply, the method comprising the steps of:

receiving at the controller, data from at least one subsea sensor arranged between the subsea side of the AC power line and the at least one subsea electric machine, a data communication link comprising an optical cable connecting said at least one sensor with said controller, an A/D conversion unit positioned at the subsea side of the data communication link for converting analogue data to digital data from at least one sensor prior to transmission of the data, an optical transceiver transmitting AD conversion results to the optical cable, a wavelength converter to change the wavelength of the output of the optical transceiver, and an offshore optical multiplexer/demultiplexer which enables the combination of several wavelengths, wherein the data includes measurements of an electrical parameter for the at least one machine; and

comparing the one or more measurements to a predetermined value.

2. The method according to claim 1, further comprising the steps of:

examining measured data from a subsea sensor; and

calculating an estimate of a motor parameter selected from the group consisting of;

motor power, motor torque, motor speed, voltage/current space vector speed.

3. The method according to claim 1, further comprising the steps of:

examining measured data from a subsea sensor; and

calculating an estimate of a power quality parameter selected from the group consisting of;

harmonic content of various frequencies, total harmonic distortion (THO), degree of unbalance (negative or zero sequence) and root mean square (rms).

4. The method according to claim 1, further comprising the steps of:

examining measured data from a subsea sensor; and

generating an event or alarm when a change in the value of the measured electrical parameter exceeds a predetermined setpoint.

5. The method according to claim 1, further comprising the steps of:

examining measured data from a subsea sensor; and

generating an event or alarm when a change in the value of the measured electrical parameter over a time period exceeds a predetermined set point or predetermined value.

6. The method according to claim 1, further comprising the steps of:

examining measured data from a subsea sensor; and

generating an estimate of torque or power value for the at least one subsea electric machine.

7. The method according to claim 1, further comprising the step of comparing an estimate of torque or power for the at least one subsea electric machine derived measured data from a subsea sensor with a topside measurement or a current setpoint value for power and/or torque.

8. The method according to claim 1, further comprising the step of estimating a motor parameter for the at least one subsea electric motor based on at least two voltage measurements and two current measurements for the subsea electric motor.

9. The method according to claim 1, further comprising the steps of:

measuring current and voltage topside;

measuring current and voltage from a subsea sensor; and

estimating a subsea measurement of the characteristic impedance between the two measurement locations.

10. The method according to claim 1, further comprising the steps of:

comparing measured data from a subsea sensor with power data topside; and

generating an event or alarm when a change in the value of the measured electrical parameter exceeds a predetermined setpoint.

11. The method according to claim 1, further comprising the steps of:

comparing measured data from a subsea sensor with power data topside; and

generating a control action to control electrical power supplied to one or more electrical loads when a change in the value of the measured electrical parameter exceeds a predetermined setpoint.

12. The method according to claim 1, further comprising the steps of:

comparing measured data from a subsea sensor; and

generating a signal for a maintenance action when a change in the value of the measured electrical parameter exceeds a predetermined setpoint.

13. The method according to claim 1, further comprising the steps of:

examining measured data from a subsea sensor; and

estimating a condition of the at least one subsea electric machine.

14. A method according to claim 1 further comprising the steps of:

converting analogue data to digital data from at least one sensor prior to transmission of the data in the A/D conversion unit positioned at the subsea side of the data communication link.

15. A system for electric power transmission arranged for operating at least one subsea electric machine comprising

a power supply

a controller;

an AC power line connecting said at least one machine with said power supply;

a data communication link comprising an optical cable;

an A/D conversion unit;

wherein said controller receives data from a subsea sensor positioned between the subsea side of said AC power line and said at least one subsea electric machine for measuring an electrical parameter for the at least one subsea electric machine the data communication link connecting said at least one sensor with said controller, wherein the A/D conversion unit is positioned at the subsea side of the data communication link for converting analogue data to digital data from at least one sensor prior to transmission of the data;

the system further comprising an optical transceiver transmitting AD conversion results to the optical cable, a wavelength converter to change the wavelength of the output of the optical transceiver, and an offshore optical multiplexer/demultiplexer which enables the combination of several wavelengths, and

wherein said controller compares the one or more measurements to a predetermined value.

16. The system according to claim 15, wherein said controller comprises an interface for handling data communication from at least one subsea sensor.

17. The system according to claim 15, further comprising at least one transformer comprising at least one integrated sensor or transformer for current and/or voltage measurement.

18. The system according to claim 15, further comprising sensors for current and voltage measurements located on the high voltage side of a subsea transformer.

19. The system according to claim 15, further comprising sensors for current and voltage measurements measured on the high voltage side of the topside transformer.

20. The system according to claim 15, further comprising sensors for current and voltage measurements inside the drive.

21. The system according to claim 15, further comprising sensors for current and voltage measurements for a plurality of subsea loads.

22. The system according to claim 15, wherein the at least one subsea electric machine is connected to a subsea power distribution system supplied by the AC power line.

23. The system according to claim 15, further comprising a step up transformer on a topside of the AC power line and a step down transformer positioned between said AC power line and said at least one subsea electric machine.

24. The system according to claim 15, wherein said controller provides measurement data to an operator workstation for supervision of the system.

25. The system according to claim 15, wherein said controller provides measurement data to an operator workstation for historical trending, generation of alarms/events based on equipment condition and/or display of condition/performance information in an operator workspace.