This paper presents a study of the problems associated with improper zone s
ettings of a distance relay. These problems include the difficulties of adj
usting the setting when a short line follows a long line or visa versa, It
deals also with setting problems like high fault impedance, in-feed current
and load encroachment. A proposed setting algorithm suitable for digital r
elays is presented. It helps in improving the dependence and the selectivit
y of distance relays. (C) 2000 Elsevier Science S.A. All rights reserved.