phase monitoring relay / distance / over-current / programmable
phase, distance, over-current
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.