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 scenarios: 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 impedance 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

sequence 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

verifying 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 suppressed 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.