Risk Analysis and Study of Wind Turbines Off-Grid Based on AC/DC Hybrid Grid

Under the background of the interaction between coastal wind power and DC transmission in the regional receiving end power grid, a new type of AC/DC hybrid power grid containing wind power is formed. Considering the short electrical distance between the DC end point converter station and the wind power concentration area is short, when a fault occurs in the DC converter station, it will lead to a large power shortage, and the wind power reactance performance is poor, which may cause a chain action to expand the accident and threaten the stable operation of the power grid. From the perspective of inverter commutation process, the mechanism and influencing factors of DC commutation failure are analyzed, and the mechanism of DC commutation failure may cause wind power tripping is illustrated. Both are verified with actual power grid by BPA. Finally, based on the simulation results, the strategies for preventing cascading tripping of wind power are proposed, and the effectiveness is verified by simulation experiments.