Measurements in RAVE and Data Access
Measurements have been collected in the scope of RAVE since 2009 by a multitude of sensors on 4 of the 12 turbines in the alpha ventus wind farm, on the substation and within the area of the wind farm itself. The 100-m-high measuring mast Fino 1 is located directly alongside the wind farm. At times, there were more than 1,200 measuring channels operating simultaneously, which have now generated more than 30 TB of data. The measurement campaigns in RAVE are ongoing so as to continue expanding the data pool.
RAVE’s goal is to promote research into offshore wind energy and make this completely unique data available for research purposes. All the measurements are stored in the RAVE data archive operated by the Federal Maritime and Hydrographic Agency (BSH); users can download the data from this data archive for research purposes.
Special regulations apply for the use of this confidential data and the user undertakes to comply with them by signing the RAVE data protection agreement. The agreement must be signed by hand by the user and the original returned to the BSH by regular mail. No modifications to the agreement text are permitted. Additional special regulations apply for especially confidential data. Further information regarding registration as a user can be found here, and you can also use this link to reach the BSH service portal.
Sensors in alpha ventus
The data pool collected in RAVE is one of a kind and contains measurements over the course of many years from:
- two different turbine models (Adwen 5000M and Senvion 5M);
- two different support structures (jacket and tripod);
- electrical parameters at the offshore and onshore substations;
- meteorological and oceanographic parameters at the Fino 1 measuring mast and within the area of the wind farm.
Alpha ventus was the first German offshore wind farm and therefore boasts the most extensive operating experience of all German offshore wind farms. The measurement campaigns began with its commissioning and are set to continue.
The sensors on the Senvion 5Ms are primarily installed on the AV04 and to a lesser extent on the AV05. The measurements are collected and supervised by GL Garrad Hassan Deutschland GmbH.
The turbine can be divided into four segments on which the sensors are installed: nacelle; rotor; tower; and support structure.
The sensors in the nacelle and the rotor blades comprise 3 acceleration sensors, 16 strain gauges, 12 temperature humidity pressure sensors, 12 fiberoptic sensors, and 6 SCADA signals.
The sensors on the tower comprise 10 acceleration sensors, 8 strain gauges, 9 temperature humidity pressure sensors, 4 tilt sensors, and 24 fiberoptic sensors.
The sensors on the jacket construction comprise 13 acceleration sensors, 131 strain gauges, and 3 temperature sensors.
Similarly to the WEA AV04, the WEA AV05 was also equipped with sensors. However, in this case, the sensors are only installed in the tower, nacelle, and rotor blades. Furthermore, considerably fewer sensors are installed than on the AV04 turbine. 2 acceleration sensors, 12 strain gauges, and 12 fiberoptic sensors were installed in the turbine. In addition, 6 SCADA signals are available.
The structural dynamic measurements on the AV07 and AV08 turbines are performed by UL International GmbH.
The sensor sites can be grouped into four categories: nacelle; rotor; tower; and support structure.
The measurements on the AV07 turbine are performed with acceleration sensors, strain gauges, fiberoptic strain sensors, tilt sensors, pressure sensors, and temperature humidity pressure sensors.
In the nacelle, there is an acceleration sensor installed on the front of the rotor and the rear of the nacelle respectively. The rotor blades are each equipped with four strain gauges on the foot at a height of 3 m. Blade 1 also features four strain gauges at 19 m and two strain gauges at 37 m as well as a 2-axis acceleration sensor in the blade tip at 55 m.
The tower segment is divided into five levels of different heights. Here there are 14 strain gauges, 10 acceleration sensors, and 2 humidity, temperature, and tilt sensors each.
There are 30 sensors for determining the relative pressure and 69 strain sensors installed in the transition piece.
32 strain gauges, 8 fiberoptic strain sensors, and 8 measurement points for the relative displacement between pile and sleeve are installed on the driven pile. The tripod construction contains 56 strain gauges and 10 acceleration sensors.
In addition, 32 signals are recorded from the SCADA system.
The Fino 1 platform captures and records a wide range of different parameters, among which specifically wind speed and wind direction at heights of between 30 m and 100 m. These data can also be viewed via the database.
Further information on Fino 1 can be found here on the Fino 1 homepage.
The alpha ventus wind farm is connected to the onshore "Hager Marsch" substation via an offshore platform and a transmission cable. Different electrical parameters are recorded at both substations and made available via the database.
Different measurements were taken over the course of the project term. Some of these resulted in data which can also be found in the database. Among other things, these include measurements concerning the salt content, oxygen concentration, and swell.
Not all of the more than 1,200 measurement channels in the alpha ventus wind farm are still in use. On the one hand, there were measurement campaigns for individual research projects which were only planned for a specific period of time and, on the other hand, harsh offshore conditions also resulted in the loss of various sensors during the operating phase. As reinstallation would be associated with considerable costs in some cases, not all sensors were replaced. This results in different availabilities of the measurements for the different sensors. The exact duration of the measurements can be checked in the research archive.