联网与孤岛场景下MMC差异化暂态穿越策略及仿真验证OA

With the widespread application of voltage source converter HVDC transmission technology,its safe ride-through capability under AC transient disturbances faces severe challenges.This paper focuses on two typical sce-narios:grid-connected transmission and isolated renewable energy transmission.First,the differentiated ride-through requirements of the two scenarios are analyzed in terms of overcurrent suppression,short-circuit current control,module overvoltage suppression,and mid-to-high-frequency resonance suppression risks.It is revealed that,when the grid im-pedance angle approaches 90°,the transient short-circuit current of the converter is mainly dominated by reactive current components.The ride-through strategies for differentiated scenarios are studied,and the impacts of fault detection,se-quence decomposition,phase-locked loop dynamics,and voltage feedforward on ride-through performance are elucidated.An RTDS real-time simulation platform was established based on China first 66 kV offshore wind HVDC project,verify-ing the effectiveness of the proposed strategy:during onshore station faults,reactive power support can be rapidly provided within 20 ms,and during offshore station faults at the 66 kV side,the fault current can be significantly sup-pressed to 9 kA.This study provides a theoretical basis and practical reference for the transient safety design of flexible DC systems in different application scenarios.