Distributed Large-Signal Stability Analysis and Parameter Optimization of Offshore Wind Power Transmission Systems

The volatility of wind speeds and the random nature of faults require offshore wind power transmission systems to maintain stable operation under large disturbance conditions. Considering the different equilibrium points of wind turbines and the bidirectional power flow of rectifier stations, the dynamic analysis of the entire offshore AC system is extremely complex, posing challenges for large-signal stability control. To address this issue, this paper proposes a distributed large-signal stability optimization method under the framework of passive control, models offshore wind turbines and rectifier stations with mixed potential functions, and ultimately derives the key constraints that strongly affect the entire offshore AC system viaBrayton-Mosercriterion. Comparing with the classic method, the proposed method rectifies the unreasonable expansion of the stable region caused by the power balance calculation, and points out the contribution of zero-sequence control in modular multilevel converters to the stable operation under unexpected power change conditions, which are still effective in expanded wind power plants and time-varying transmission line parameters. Finally, the correctness of the theoretical analysis and parameter settings is verified by simulation results.