Non-Unit Protection Algorithm for MTDC Systems Based on Transient Variance of Current

Fast detection and isolation of the fault line within the “capacitor discharging stage” after direct current (DC) faults has become a major challenge for multi-terminal DC (MTDC) systems comprised of voltage source converters (VSCs). Existing protection schemes rely on tedious numerical simulations to determine the threshold value. To tackle that, this paper first defines a time-domain index for f...