AN INVESTIGATION INTO THE USE OF ADAPTIVE SETTING TECHNIQUES FOR IMPROVED DISTANCE BACKUP PROTECTION

Changes in power system operating conditions adversely affect the reac h point accuracy of distance relays, This paper will discuss adaptatio n of the settings of distance relays within an integrated digital hier archical protection system for the optimisation of relay performance, Specific reference will be made to adaptation of the zone 3 setting to ensure optimal relay performance over a wide variety of operating con ditions. Results illustrating the performance of adaptive methods comp ared to conventional fixed settings will be presented for an applicati on study of the North Wales 400 kV network.