SPAJ 142 C Combined Overcurrent and Earth-Fault Relay User Manual

This document is a user manual and technical description for the SPAJ 142 C combined overcurrent and earth-fault relay, which provides selective short-circuit and earth-fault protection for radial feeders in power systems. It details the relay's protective functions, including three-phase low-set and high-set overcurrent units, non-directional earth-fault protection, breaker failure protection, and features such as IDMT characteristics, output relay configuration, and serial communication.