Date Code 20100129 Instruction Manual SEL-751A Relay
Section 1
Introduction and Specifications
Overview
The SEL-751A Feeder Protection Relay is designed to provide overcurrent
protection to feeders, transformers, etc. The basic relay provides instantaneous
and inverse time-overcurrent protection. Voltage-based, Arc-Flash Detector
(AFD)-based, and RTD-based protection are available as options. All relay
models provide monitoring functions.
This manual contains the information needed to install, set, test, operate, and
maintain any SEL-751A. You need not review the entire manual to perform
specific tasks.
Features
Standard Protection
Features
➤ Phase Instantaneous Overcurrent (50P)
➤ Ground (Residual) Instantaneous Overcurrent (50G)
➤ Neutral Instantaneous Overcurrent (50N)
➤ Negative-Sequence Overcurrent (50Q)
➤ Phase Time Overcurrent (51P)
➤ Ground (Residual) Time Overcurrent (51G)
➤ Neutral Time Overcurrent (51N)
➤ Negative-Sequence Time Overcurrent (51Q)
➤ Frequency (81)
➤ Breaker Failure Protection
➤ Breaker Wear Monitor
Optional Protection
Features
➤ Autoreclosing Control (79)
➤ Voltage-Based Protection
➢ Undervoltage (27)
➢ Overvoltage (59)
➢ Negative-Sequence Overvoltage (59Q)
➢ Residual (Zero-Sequence) Overvoltage (59G)
➢ Power Elements (32)
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