Study on protective performance of HVDC transmission line protection with different types of line fault

HVDC line protection system is composed of traveling wave protection as the main protection, under voltage protection and differential protection as the backup protection. The responses of the HVDC line protection criterion are not same at different fault situations, and it also makes the operation characteristics of the line protection quite different. In this paper, based on the EMTDC simulation platform and an actual HVDC power transmission system and its protection system, the changes of voltage and current of the HVDC line are measured, and the influences of fault location, fault resistance and the external disturbance to the HVDC line protection are also analyzed in detail. At the same time, the relation between the rejecting act of the protection and the factors mentioned above are also discussed, and some improvement schemes are also proposed.