Wind power plants (WPPs) are increasingly mandated to provide temporary frequency support to power systems during contingencies involving significant power shortages. However, the frequency support capabilities of WPPs under derated operations remain insufficiently investigated, highlighting the potential for further improvement of the frequency nadir. This paper proposes a bi-level optimized temporary frequency support (OTFS) strategy for a WPP. The implementation of the OTFS strategy is collaboratively accomplished by individual wind turbine (WT) controllers and the central WPP controller. First, to exploit the frequency support capability of WTs, the stable operational region of WTs is expanded by developing a novel dynamic power control approach in WT controllers. This approach synergizes the WTs’ temporary frequency support with the secondary frequency control of synchronous generators, enabling WTs to release more kinetic energy without causing a secondary frequency drop. Second, a model predictive control strategy is developed for the WPP controller. This strategy ensures that multiple WTs operating within the expanded stable region are coordinated to minimize the magnitude of the frequency drop through efficient kinetic energy utilization. Finally, comprehensive case studies are conducted on a real-time simulation platform to validate the effectiveness of the proposed strategy.

With the expansion of offshore wind farms (OWF), attention has been paid to the voltage stability of wind turbines (WT) in the scenario of island operation mode. Excessive terminal voltage in a few WTs due to terminal voltage distribution will reduce their power generation efficiency or potentially lead to a trip. A calculation methodology for OWFs’ single-cable layout boundary is proposed in this paper to optimize the number of WTs connected to a single cable. Enforcing the layout boundary can improve the WTs’ terminal-voltage stability and prevent degradation of power generation efficiency. First, the terminal-voltage function is constructed based on the power flow of the π-type cable, and the terminal-voltage distribution within WTs connected to the single cable is revealed. Second, in several grid-connected voltage scenarios, the terminal voltage boundaries are set to limit the number of WTs connected to a single cable. Case studies built in MATLAB are carried out to verify the performance of the proposed terminal voltage boundaries. OWFs’ single cable layout boundary can effectively evaluate the terminal voltage stability of WTs in current OWFs and guide the layout planning of upcoming wind farms.