Analysis of High-Speed-Distance protection

The modern power system often operates at its performance limit. Therefore, uncontrolled events, e.g. short circuits, can quite rapidly cause thermal stress of system components as well as instability of the entire power system with the risk of longer energy interruption. In order to maintain the reliability and security of the power system at good level, the reaction to such undesirable events must be very quick. This task is undertaken by protection equipment. One such fast protection function is the High-Speed-Distance (HSD) line protection, which provides selective tripping of the line within half of the fundamental cycle after short circuit beginning. In this paper, the High-Speed-Distance protection function is systematic analyzed.