Energi og miljø - masterstudium (5-årig) - Master of Science in Electric Power Engineering, NTNU

TET4200 Marine and offshore power systems

– Faglærer Arne Nysveen
The course focuses on three application areas: topside power system on platforms (floating and non-floating) for oil and gas production, electric propulsion of ships and subsea power systems for subsea oil and gas production.

Platforms are large dedicated industrial plants with a power consumption of 10-30 MW. The power systems are autonomous. Typical voltage levels are 6.6kV, 11kV or 22 kV. Compared to utility power systems, some loads are large with respect to the generation capacity and the physical distance between generation and consumption is small. Design and operation of these power systems differs from traditional utility power networks.

The electrical power is produced by synchronous generators powered by gas turbines. Modelling and analysis of the dynamics of these units are therefore essential for studying topside power systems. The program SIMPOW is used to simulate electrical and mechanical dynamics during the course.

Electrical propulsion of ships has gained increased popularity during the last 10 years. Electric propulsion enables increased manoeuvrability (podded propulsion), better fuel economy, greater flexibility in design and better comfort. Electrical propulsion is mostly used for cruise ships, supply ships, ice breakers and ferries. The main power source is normally diesel-engines. Each propulsion motor is connected to frequency converter.

Subsea power systems are power systems on the sea bed used to supply subsea processing units. The trend is to move more of the process equipment from platforms/floating vessels to subsea installations and connect the field directly to on-shore facilities. Installations so far are normally booster pumps for enhanced recovery and increased production. One subsea separation unit has been in operation at the Troll field (Troll Pilot) sine 1999/2000. The unit is supplied with a water injection pump injecting the produced water back into the formation . In the near future large field developments such a Ormen Lange is planned with subsea gas compressor necessitating some 50MW of power subsea.

The students will learn how to design, construct, model and analyze marine power systems, with focus on power systems on ships with electrical propulsion, floating vessels for oil&gas production and subsea power systems.

The students are expected to have basic knowledge in electrical machinery in design, operation and modelling equivalent to the course TET4110 Electrical Machines. Knowledge in modelling and analysis of load flow and short circuits in power systems equivalent to the course TET4115 Electrical Power Systems.

Course content:
Application of electrical power on marine installations, i.e ships with electrical propulsion, vessels for production of oil&gas and subsea oil&gas process installations. Power distribution layout, system dimensioning, short circuit analysis, start-up of large motors, thermal and mechanical dimensioning, cable modelling. Topside and subsea large motor drives. Power generation. Subsea motors, subsea high voltage equipment. Electrical heating of subsea pipelines.

Teaching: Lectures, project work and written exercises.

Compulsory exercises

  • 6 out of 10 exercises
  • 1 project in analysis using SiIMPOW

Evaluation: Written exam 100%

Semester plan:

  • About the course. Course content. Practical information
  • Introduction to production of oil and gas (Guest)
  • Offshore power systems (Guest from Statoil)
  • Topside power systems
  • Steady-state modelling and analysis. Load flow
  • Short circuit calculation
  • Machine dynamics
  • Stability analysis
  • Start-up of large machines
  • Mechanical and thermal aspects
  • Electric propulsion
  • System description and applications
  • Diesel-electric propulsion
  • Drives
  • Subsea power supply
  • System description
  • Subsea high voltage equipment
  • Modelling of cables
  • Motor drives with long cables
  • Electrical heating of flowlines

The students will learn how to design, construct and analyze marine power systems, with focus on power systems on ships, floating vessels for oil&gas production and subsea power systems.

Stated at start of the semester.

Lectures and compulsory exercises. Analysis of marine power systems with the simulation program SimPow. The course is given in English. Postponed examination may be changed from written to oral examination.

TET4200 - INFO