Maximizing line protection reliability, speed, and sensitivity

This paper describes several commonly applied line protection schemes, including distance schemes, directional comparison schemes using distance and directional elements, and line current differential schemes. Using analysis tools like fault trees, power system studies, and event analysis, we evaluate and compare these protection schemes in terms of speed, sensitivity, dependability, security, and selectivity. The paper considers the use of various communications channels, including direct relay-to-relay fiber-optic channels and multiplexed digital fiber-optic networks. The paper also discusses some practical considerations for evaluating line protection schemes when faced with complications like series compensation, mutual coupling, single-pole tripping and reclosing, three-terminal lines, and short lines.