The record-breaking 32 MW subsea compression system for Ormen Lange is in its final delivery stages and recently reached a major testing milestone. The power system, a gamechanger for large scale subsea processing equipment and the world’s longest subsea power step out, has now been successfully tested in a full-scale dynamic test arrangement. The compression system, which is built up of four 8 MW multiphase compressors, each containing two contra-rotating motors, will be supplied from two onshore Variable Speed Drives. The step-out distance is 120 km, which is close to three times longer than any existing variable frequency step-out. Onshore VSD output transformers will increase the voltage to enable long distance transmission, while subsea step-down transformers will transform the voltage back to motor-voltage.

This power configuration with actual delivery equipment has now been tested at the state if the art facilities at Horsøy in a unique 16 MW test arrangement. The test setup includes an actual compressor, two regenerative back-to-back motor/generator arrangements, a subsea transformer, umbilical cable simulator and the onshore equipment. The full-scale test confirmed excellent performance for all load and transient conditions and has given invaluable added confidence in the overall performance before the system will be installed at the field.

This presentation will share insight to the evaluation and confidence steps taken, from concept idea and analysis, to system verification testing and execution of the dynamic full load test for one of Norway’s most important and innovative subsea gas developments.