Offshore power curve verification with Nacelle 2-beam LIDAR on V164

Tue Hald 1, Paul Mazoyer1
1MHI-Vestas, Denmark, Denmark, 2Leosphere, Paris, France


Cost of offshore power curve verification has reached level which triggered interest across the industry for new cost-effective methods. In 2013, the Danish public found for technological innovation successfully finished the first standard for power curve verification with nacelle mounted Lidars which has been widely used since. Following recommendations of the report, MHI-Vestas has undertaken a test to validate the use of 2-beam Wind Iris to perform contractual power curve verification for large offshore wind turbines. The use of 2-beam Wind Iris raised several challenges for which MHI-Vestas has to check. Operational challenges were first challenge since limited part of the nacelle roof is accessible and then a dedicated location should be found to install the Lidar. Besides this location should ensure that Laser beam were not hitting hard target. MHI-Vestas turbine is 164 rotor diameters inducing a free induction area at, at least, 328 meters, which required data availability of the device at large distances. MHI-Vestas defined a test protocol and then undertook the test to validate above points.


At Osterild test site, MHI-Vestas has installed a V164 turbine for several test purposes. Osterild test site is operated by DTU and has a long experience in testing large wind turbine, the site is flat and free for obstacles. A 2-beam Wind Iris was installed on the top of turbine and was operated for 16 weeks. The test procedure could be entirely applied to verify if Wind Iris was able to perform PCV for large Wind Turbine.


MHI-Vestas observed ability of 2-beam Wind Iris to measure horizontal wind speed at 2,5D and further at Osterild indeed good location was found on the nacelle roof which is accessible and from which no beams are blocked by any hard target. Besides, there is enough wind speed measurement at 410+ meters to perform a PCV in reasonable duration.


EUDP procedure gives a standard to perform PCV with 2-beam Wind Iris and MHI-Vestas has successfully verify that the 2-beam Wind Iris can be used for PCV on large wind turbine. The 2-beam Wind Iris is used to perform PCV offshore decreasing dramatically the cost and reducing the time required. MHI-Vestas offers the use of PCV with 2-beam Wind Iris for contractual verification stepping up in the PCV with cost-effective devices.


The attendee will learn :
• How to use 2-beam Wind Iris to perform contractual PCV
• How to tackle challenge of installing 2-beam Wind Iris on large wind turbine offshore
• Which are the statistics of measurement of a 2-beam Wind Iris at a typical Danish site