Global sensitivity analysis of distance protection performance for submarine transmission systems

The distance protection performance depends on the accurate definition of the relay settings. These are computed from the line impedance, which needs, for its calculation, various parameters (such as geometry and cross-section of the cable, soil properties); their uncertainty might jeopardize the performance of the fault location algorithm. Via global sensitivity analysis, this paper investigates which are the main drivers of the distance protection performance in a submarine transmission system. The results underscore the need to better characterize the earth resistivity (via direct or indirect measurement), and the risk of the common practice to adopt “default” values for it. Also, the cable model of the EMT software tools used to compute the line impedance can be, already perse, an error source for distance protection algorithms.