Contents I. Introduction
Power transmission and distribution lines are the vital links that achieve the essential continuity of service of electrical power to the end users. Microprocessor-based distance relays are widely used for transmission line protection. Innovative developments within microprocessor-based relays have created new ways of reacting to the data available and responding to the possible information that can be extracted from these data. During the last 20 years, microprocessor-based relays have progressed from a laboratory setup to practical application by the electric power industry [1], [2].
