Unified pilot protection based on digital communication system

Fiber Optic communication has been applied widely in power protection system. The appearance of digital communication technology makes all kinds of information exchange reliable and fast, and the construction of unified pilot protection system is possible. Based on abundant information, the unified pilot protection system can apply several protection criteria to improve the performance of relay protection system and accomplish some auxiliary functions. In this paper, the technical background, protective IED configuration, information frame classification and format of unified pilot protection system are introduced, the principle of some unified pilot protection functions such as protective relaying improvement, auto reclosing cooperation, power transmission line parameter and transition resistor measurement and calculation are studied.