CONTROL METHOD FOR SUPPRESSING OVERVOLTAGE UNDER FAULT AT RECEIVING-END ALTERNATING-CURRENT (AC) SYSTEM OF HYBRID HIGH-VOLTAGE DIRECT-CURRENT (HVDC) TRANSMISSION SYSTEM

The present disclosure provides a control method for suppressing an overvoltage of the receiving-end F/HMMC under the fault at the receiving-end alternating-current (AC) system of the hybrid high-voltage direct-current (HVDC) transmission system. After a short-circuit fault occurs in a receiving-end alternating-current (AC) system of the hybrid HVDC transmission system, an AC voltage drop is generated, and the effective voltage of the receiving-end AC bus at the current time is measured. Because the hybrid modular multilevel converter (MMC) has a capability of actively decreasing the DC voltage for operation, on a premise of ensuring that its output current is always within a rated current range, a control manner of setting the reference DC voltage and making the reference DC voltage not greater than the effective voltage of the AC bus enables receiving-end power to be sent out, thereby suppressing an overvoltage of the receiving-end F/HMMC.