Focusing on the issue that the conventional protection relay is unable to clear the faults rapidly occurring within the whole protected multi-terminal lines in a medium/low voltage system

this paper presents a new scheme of current differential protection based on the fiber optical communication channel for multiterminal lines. The protection principle

the data synchronization

the communication mode

the configuration of hardware and protection functions are described in detail. The dynamical simulation test results show that the performance of the protection relay is excellent

which can completely meet the requirement of rapid fault clearing for lines with taps.