New simple formulations and validations for digital implementation of pilot protective relaying schemes

This paper presents new simple formulations for digital implementation of pilot protective relaying schemes. Pilot relaying systems use a communication channel to deliver information from a local relay terminal to a remote relay terminal. The pilot relaying allows high-speed tripping for faults occurring on its designated protected line that improves the reliability of protective relaying for transmission lines. This paper presents new formulations for typical pilot protective relaying schemes, including Directional Comparison Blocking (DCB), underreaching direct transfer trip (DTT), permissive overreaching transfer trip (POTT), and permissive underreaching transfer trip (PUTT). The main feature of these new formulations is focused on facilitating simple and robust digital implementation for live, operating transmission line protection. Validations of these new formulations are presented in the paper.