Type 3 wind power plants (WPPs) in a series compensated electricity network may cause undamped wind related subsynchronous control interaction (W-SSCI). High amplitude subsynchronous oscillations can cause significant problems in the electricity network. This study investigates whether the possibility for W-SSCI in a highly meshed series compensated electricity network can be reliably analyzed using SISO impedance scanning, or whether W-SSCI should instead be analyzed using MIMO impedance scanning. This study also investigates the impact of electricity network topology and parallel Type 3 WPPs on the possibility of W-SSCI in a series compensated electricity network.

Based on the results, it seems that SISO impedance scanning is reliable in Type 3 WPPs up to frequencies of 30 Hz. In this study it was found that the electricity network topology and parallel Type 3 WPPs have a significant impact on the possibility of subsynchronous oscillations in a series compensated electricity network. The results also showed that Type 3 WPPs often caused a parallel resonance peak in the frequency-domain impedance curve of the background network. The frequency of the oscillation observed in the time-domain analyses almost always corresponded to the frequency of the parallel resonance peak and indicated high possibility for undamped W-SSCI.