1.State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources (North China Electric Power University), Beijing 102206, China;2.State Grid Shanghai Songjiang Power Supply Company, Shanghai 201600, China

The large-scale wind power bases are mostly located in the inland of northwest China, which require cross-regional accommodation through high voltage DC transmission. To deal with the uncertainty of wind power output and improve the wind power accommodation level, the traditional line commutate converter based high voltage DC needs active power regulation according to the change of wind power output. However, if it is not well controlled, it may cause frequent operation of DC reactive power regulation equipment, which is not conducive to the stable operation of the DC system. A day-ahead two-stage stochastic optimal dispatch model of AC/DC interconnected power grid is established based on the two-stage stochastic programming, which fully considers the feasibility of real-time day-ahead plans. The DC power is regarded as a flexible resource and the steady-state operation model of converter stations is introduced to describe the DC reactive power characteristics to accurately limit the operation of reactive power equipment. Aiming at the nonlinearity of the model, the first-order Taylor expansion is used to linearize the steady-state operation model of converter stations, and the accuracy of the linearization is verified. Finally, the effectiveness of the optimal dispatch strategy is verified by the wind power DC transmission system.