Saarblitz, Wind farm in HDR,, creative commons by-nc-sa 2.0

San Gregorio

Data Provider: 

Sorgenia Green s.r.l.

Data accesibility: 

Site Description: 

The wind farm is placed in southern Italy on a very complex terrain area; prior the installation of the turbines site assessment was done using met-mast measurements.

The measurements of wind speed and direction and the main meteorological data (temperature, pressure, humidity) began in 2006 while the SCADA data collection was carried out from 2009, at the beginning of the farm operation. The wind farm consists of 17 Siemens SWT-2.3-93 wind turbines, each producing a rated power of 2.3 MW at around 12 m/s with a rotor diameter of 93 m and a hub height of 80 m. The terrain is quite awkward, with slopes up to 60% close to the turbines, and the wind farm layout is complex and large, resulting in non trivial combination of complex wind flow and wake interactions. The site is also characterised by significant icing and lighting effects.

A further complexity for the site is the presence of a windfarm in the neighbouring, which potentially affects the operation of some turbines. In the neighbouring wind farm are installed 11 turbines with a specific nominal power of 3 MW, a hub height of 78 m a.g.l. and a diameter of 90 m.

Table I: Wind Turbine characteristics

Figure 1   Layout of the San Gregorio wind farm on elevation contours map.

Table II Wind farm layout details.

Table III Inter-turbine distances (number of rotor diameters)

All the wind turbines at San Gregorio wind farm are SWT 92.6m, 2.3MW operating with variable speed and variable pitch. The operational behaviour of the wind turbines is characterised with:

  • Official power curve;
  • Thrust coefficient curve;
  • Rotor speed curve
  • Pitch curve as a function of the wind speed

Figure 2  Power Curve for SWT-2.3-93m installed at San Gregorio Magno


The wind turbines are equipped with SCADA system, storing usual plant information on a 10 minute basis, i.e. nacelle wind speed, yaw angle, pitch angle, rotor speed, electric power and so on, plus a series of counters providing awareness of the historical evolution of the status of each turbine.

Six meteorological masts within the park area have been collecting data both in the assessment and operational phases and are useful for wind flow and wake interactions study. The most important ones for wake interactions investigation are SNG3 and SNG6, which, as can be seen from the layout above, lie close to a raw of turbines. SNG3 met mast is free from wakes in the 230°-330° sectors and has collected data from 2006 up to half 2012, for a total amount of 2261 days. It includes anemometer and wind vane at 30 and 40 m levels and anemometer, hygrometer, thermometer and barometer at 10 m level. The additional meteo mast SNG6 has been installed on January 2011 close to SNG3; it is free of wakes from the 0°-100° sectors and includes 11 anemometer and wind vane channels at three different levels (76, 32 and 9 m) and an anemometer at 80 m level.

Table IV Met-mast position and measurement campaign details.

Measurement Campaign: 

An interesting feature of the dataset is that there is a window from December 2006 to June 2007 where SNG2, 3, 4 and 5 were simultaneously collecting data for free wind flow studies. Being the wind farm very large and the anemometer above displaced quite far the one from the other, such databases constitute a laboratory for investigating the complexity of wind flow along the farm.


The most interesting study on wakes can be focused on the row of turbine number 10 to 13.

Anyway such turbine cluster could be affected by wakes due to a neighboring wind farm especially in the 90° sector .


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