PSI - Issue 64

Serdar Soyoz et al. / Procedia Structural Integrity 64 (2024) 484–491 Soyoz et al. / Structural Integrity Procedia 00 (2024) 000 – 000

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2.2. Data analysis In-house developed software was used to get data remotely and perform modal identification automatically. Data is first recorded to a local computer and then transferred to main server. Enhanced frequency domain decomposition technique proposed by Brinckner et al. (2001) was used to obtain modal parameters of the wind turbine for three bending modes in both wind directions. Power spectral densities for operating and non-operating wind turbine are given in Fig. 3. Operating wind turbine was assumed to behave like a non-operating wind turbine with scattering modal frequencies. Scattering of the first three bending mode frequencies over one year can be seen in Fig. 4. According to the frequency vs. day plots, it is obvious that the first mode is almost constant in both wind directions during the monitoring of the turbine. On the other side, the second and third bending mode frequencies show a clear scattering. The mean values of the first, second and third mode frequencies were 0.47 Hz, 3.30 Hz, 9.31 Hz in the first wind direction and 0.46 Hz, 3.31 Hz, 9.37 Hz in the second wind direction.

Fig. 3. Power Spectrum of operating and non-operating wind turbine.

Fig. 4. The first three frequencies in the first and second wind direction.