Numerical current differential protection
The REL 356 numerical current differential protection provides high speed protection for long and short lines. It is particularly suitable for lines too short to be effectively protected by distance relays and for tapped load applications.
The current-only measuring principle offers advantages such as insensitivity to power swings, mutuals and problems associated with ccvt’s. Communication interfaces for 9600 bps audiotone or 64 kbps direct digital or fiber optic are available. The transfer trip function utilizes the same communication channel and can be selected to operate separate trip contacts. The REL 356 protection system also provides digital fault recording, fault locating and extensive target records.