Comparative study of DC short-circuit in MMC-HVDC system considering FCL

One of the main challenges of high voltage direct current systems is the detection and isolation of direct current short circuit faults, which present a pronounced dc current rise rate; these faults must be detected and isolated within a few milliseconds of their occurrence to prevent the collapse of the system. This is crucial to give the reliability that one of these systems must have. For this purpose, the use of fault current limiters has been implemented in each of the lines. This article analyzes and describes three types of short-circuit faults located at different points in the system to describe the behavior of the short-circuit phenomenon, as well as the influence of the fault current limiters in these conditions. The case studies are evaluated in the PSCAD/EMTDC electromagnetic transient analysis tool.