ABSTRACT
Pilot protection used for lines provides the possibilities of high-speed simultaneous detection of phase-and ground-fault protection for 100% of the protected section from all terminals: the ideal primary protection goal. It is a type of differential protection for which the quantities at the terminals are compared by a communication channel, rather than by a direct-wire interconnection of the relay input devices. The latter is impractical because of the distances between the several terminals. Similar to differential schemes, pilot schemes provide primary zone protection and no backup. Thus, they do not require coordination with the protection in the adjacent system unless additional backup is included as a part of the pilot scheme.
