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.
50 Hz EHV and HV applications.
Designed to meet stringent single-pole tripping requirements.
Contains all the protective elements and control logic necessary to protect, monitor, and control any noncompensated overhead line.
The unique adaptive directional element chooses between negative- and zero sequence quantities based on signals generated by a disturbance.
Power-swing blocking is provided during the single-pole-open period immediately following a single-pole trip.