Multi-Phase Autoreclose Function Installed in Line Differential Relay

Multi-phase auto-reclosing has been applied in Japan since the early 1970’s, Multi-phase autoreclosing can be applied to double-circuit lines and enables high-speed reclosing without synchronism and voltage check in case healthy phase is two or more under multi-phase fault in both lines. Almost Japan utility adopted multi-phase autoreclosing instead of single-and three-phase reclosing, as it became evident that multi-phase autoreclosing performed better than a single-and three-phase reclosing. This paper describes the introduction and benefits of multi-phase autoreclosing, based on transmission fault data and with comparison to other types of autoreclosing.