Method and apparatus for fault prediction of sub-module in flexible direct current transmission converter valve

Method and apparatus for fault prediction of a sub-module in a flexible direct current transmission converter valve by: determining if sub-module is in a charging or discharging state according to topology of sub-module and direction of collected bridge arm current, in connection with control instruction for the sub-module, the control instruction including switching in, switching out and blocking; determining a voltage rising or reducing rate according to the magnitude of current and capacitance of the sub-module or according to loss and capacitance of the sub-module; predicting a voltage after a pre-set time; comparing the actual voltage measured after the pre-set time and the predicted voltage to determine if a fault occurs. The voltage reducing rate may be determined according to the magnitude of the current and the capacitance of the sub-module if the sub-module is in a fast-discharging state, or according to the loss and capacitance if the sub-module is in a slow-discharging state ...

Method and apparatus for fault prediction of sub-module in flexible direct current transmission converter valve