The past years have seen a rapid increase in the deployment of large-scale wind power plants (WPPs) in transmission grids. The dynamic interactions between wind turbines (WTs), power transmission cables, and other electrical infrastructure of WPPs pose challenges to the stability and quality of electricity supply, particularly under diverse grid conditions. The interactions tend to be worsened with longer transmission cables [1]. A harmonic instability issue that features a 451 Hz resonance is manifested in an offshore WPP located in the North Sea [2]. During a submarine cable outage, an offshore WPP situated in England encountered instability due to sub-synchronous resonance at around 8.5 Hz [3].