Distance protection must provide fast and selective fault clearance during system faults. The performance level of a distance protection device is primarily determined by its speed of operation and the accuracy of its distance measurement. Both these, criteria are however not constant, they are influenced by system and fault conditions such as for example distance to fault, arc resistance etc. and by the quality of the measured signals. In this paper, it is shown how the current transformer influences the accuracy of the distance measurement and how modern numerical distance relays respond with selfcorrecting action.

كلمات كليدي:

Distance protection, current transformer, transient behaviour