Phase monitoring relay / distance / over-current / programmable
SEL-321-5 Schweitzer Engineering Laboratories


  • Measured/monitored value:

    phase, distance, over-current

  • Other characteristics:

    programmable, digital


SEL-321-5 Phase and Ground Distance Relay

The SEL-321-5 Relay is designed especially for EHV and HV applications on 50 Hz systems. The relay provides enhanced single-pole tripping, phase and ground distance, directional overcurrent, negative-sequence overcurrent, and fault locating. The SEL-321-5 Relay contains all the protective elements and control logic necessary to protect, monitor, and control overhead lines.


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