## 4 Analyses
### Q2: Do External Conditions Have an Effect on Information Loss?
The lower and upper dash lines represent the 5–95 th percentile of the distribution. Solid lines represent mean values. The different colors denote the various aggregation periods that have been analyzed. All signals are not normalized, the y-axes are in natural units. For a less overloaded presentation, the axes do not feature any unit labelling. Please refer to Table 4 for the units of this plot. The first observation to Figure 11 is that range of the variations in information loss always increased with the aggregation time. Some signals, in particular grid frequency, ambient, and main bearing temperature, showed little variation over the entire range of wind speed values, the span of the 5-95 th range was almost constant for all wind conditions. All other signals had visible variations in their information loss ranges and their mean values oscillated around zero. As it can be seen from the dashed lines, there were some instances for which the difference range between the original and aggregated signal was particularly large, even pronounced peaks could be obtained: Those peaks can either be symmetric around 0, e.g., for all temperatures, or asymmetric, as was the case for the active power, the pitch angles, the currents, and also slightly for the voltages. The error range was prominently large for the active power for wind speeds between 6 and 12 m/s and aggregations of 300 to 600 s with an information loss between \(-400\) kW and 400 kW. Currents also varied heavily in that wind speed region with an information loss span between \(-400\) and 300 A. Additionally, in the same region, temperatures had their maximal variations, in the case of the gearbox shaft bearings as high as \(-3\) to 3 \({}^{\circ}\)C. However, little to no variation is seen for the main bearing temperature whose range of variation is between \(-0.20\) and \(0.35\,{}^{\circ}\)C. For signals such as rotor, generator speed, and the temperature of the generator bearing the range of variation of information loss was high for lower wind speeds. It was greatly reduced and constant once at nominal operating conditions with wind speed above 12 m/s. The highest error range could be observed for very low wind speeds below 5 m/s. Additionally, for pitch angles the error is extremely high with \(-15\) to 10 deg for these low wind speeds. A similar trend of an almost constant error range for wind speeds above 12 m/s could be seen in most of the temperatures. Though, especially for temperatures related to the gearbox the transition to this constant regime was much smoother and the span of the range approached low values only for very high wind speeds, i.e., winds above 20 m/s. While most signals showed large variations around the transition phase towards nominal power, a noticeable exception was the wind direction that varies greatly between \(-75\) and 75 degrees for wind speeds around 0 m/s and stabilized between \(-25\) and 25 degrees for wind speeds above 5 m/s. A further prominent observation was the error of the pitch angles for wind speeds between 5 and 10 m/s where it stayed almost at 0. The error of the wind speed itself increased steadily with increasing wind speed. Furthermore, the mean value of the error decreased, meaning an underestimation of the wind speed upon aggregation. As a general additional remark: For aggregations up to 60 s the variation of information was low compared to aggregations of 300 to 600 s. As an example, in the case of the gearbox shaft bearing 1 temperature, information loss spanned well below \(-1\) and 1 \({}^{\circ}\)C for aggregations up to 60 s, whereas for 600 s aggregation this range varied between \(-3\) and 3 \({}^{\circ}\)C.