A general approach to sine comparators.

This paper reports a comprehensive general analysis of sine comparators for distance protection of transmission lines. A mathematical basis is developed for realizing rectilinear characteristics and a graphical construction is presented to derive the necessary input signals for the sine comparators for obtaining a variety of pick-up characteristics on the impedance plane. A new criterion in multi-input sine comparators (sequence comparators) for the discrimination of faulty and healthy conditions of a protected transmission line section is established and a comparator model in schematic form is presented to realize the popular quadrilateral polar characteristics based on the new criterion. [ABSTRACT FROM AUTHOR]