Fault Ride-Through Capability Enhancement Strategy for VSC-HVDC Systems Supplying for Passive Industrial Installations

This paper proposes a modified current-limit strategy (MCLS) and a frequency hysteresis control (FHC) for improving the disturbance ride-through capability of a VSC-HVDC link supplying passive industrial installations. Since industrial loads are more sensitive to voltage drops than frequency deviations, it is essential to guarantee the stability of voltage during severe faults. The development of the control methods includes three steps. First, the main factor that affects the ac voltage in the passive industrial system is analyzed in order to enhance the voltage stability more effectively. Second, according to the analytical results, the MCLS is proposed to increase the ac voltage in transient conditions. Third, in order to make the MCLS have a better control result, the FHC is added to the VSC controller with the MCLS, which can also further enhance the ac voltage of the passive system. The simulation tests under metallic single-phase and three-phase faults are performed in PSCAD/EMTDC, and the results verify the validity of the control methods.