基于二极管整流单元高压直流系统的混合型构网与跟网海上风电场中构网型风电机组比例研究

This study analyzes the stability and reactive char-acteristics of the hybrid offshore wind farm that includes grid-forming(GFM)and grid-following(GFL)wind turbines(WTs)integrated with a diode rectifier unit(DRU)based high-voltage direct current(HVDC)system.The determination method for the proportion of GFM WTs is proposed while considering sys-tem stability and optimal offshore reactive power constraints.First,the small-signal stability is studied based on the devel-oped linear model,and crucial factors that affect the stability are captured by eigenvalue analysis.The reactive power-fre-quency compensation control of GFM WTs is then proposed to improve the reactive power and frequency dynamics.Second,the relationship between offshore reactive power imbalance and the effectiveness of GFM capability is analyzed.Offshore reac-tive power optimization methods are next proposed to diminish offshore reactive load.These methods include the optimal de-sign for the reactive capacity of the AC filter and the reactive power compensation control of GFL WTs.Third,in terms of stability and optimal offshore reactive power constraints,the principle and calculation method for determining the propor-tion of GFM WTs are proposed,and the critical proportion of GFM WTs is determined over the full active power range.Final-ly,case studies using a detailed model are conducted by time-domain simulations in PSCAD/EMTDC.The simulations verify the theoretical analysis results and the effectiveness of the pro-posed determination method for the proportion of GFM WTs and reactive power optimization methods.