A device for controlling fault ride-through of a
power grid of a flexible direct-current
transmission system comprises a
control unit, a detection unit, a switchable braking
resistor unit, a power
voltage regulation unit and a full-bridge braking unit, wherein the switchable braking
resistor unit is used for primary power release of output of a rectification end, the power
voltage regulation unit is used for secondary power release of output of the switchable braking
resistor unit, and the full-bridge braking unit is used for
tertiary power release of output of an inversion end. By a method for controlling fault ride-through of the
power grid of the flexible direct-current
transmission system, direct-current side
busbar voltage and alternating-current side
busbar voltage are detected in the real time, and when a fault
signal is detected, a direct-current change-over switch is switched off, and a second fully-controlled switch is switched on to dynamically enable a first fully-controlled switch to be on for dynamic
voltage regulation, so that maximum residual
power transmission is achieved. The method is capable of effectively inhibiting
overvoltage of a direct-current
busbar, avoiding latching of devices of the direct-current
transmission system and guaranteeing maximum residual
power transmission, and the devices of the direct-current transmission
system can be normally operated during fault.