The invention relates to a control protection system for a flexible direct-current power transmission system. The control protection system comprises a programmable logic device array, wherein the input interface of the programmable logic device is connected with the output end of an analogue-digital conversion module, and the analogue-digital conversion module is controlled to sample the voltage and the current of the flexible direct-current power transmission system, carrying out operation processing on the received sampling data to generate the control signal of each switch device; a complex programmable logic device is connected with the programmable logic device array, and the programmable logic device array is used for outputting the control signals of the switch devices to the complex programmable logic device; a central processor carries out information interaction with the programmable logic device array, and is used for carrying out logical operation according to the sampling data transmitted by the programmable logic device array, and the direct-current voltage and running state data of each power module, so as to generate an output command; the central processor is connected with an input-output module and a communication module respectively, and the communication module is further connected with a display screen. The control protection system disclosed by the invention can be widely applied in the field of power electronic converters.