No longer in production

SEL-321-5

Phase and Ground Distance Relay

SEL recommends selecting the SEL-311C Transmission Protection System in place of the SEL-321-5. Replacement product: SEL-311C

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.

Use acSELerator Team SEL-5045 Software to automatically gather relay event reports on your PC and manage them with a database.

Use synchroWAVe Event Software to display oscillograms and vector diagrams to analyze event reports.

Four zones of phase and ground distance protection.
Quadrilateral (and/or mho) characteristic for ground distance protection.
Adaptable directional element selects best measurement technique (negative-sequence or zero-sequence impedance).
Independent timers for phase and ground distance time-delayed trips.
Any zone may be set forward or reverse.
Patented Mirrored Bits technology for communications-aided tripping schemes (eight independent channels in each relay).
Flexible communications and RTU features including three independent ports; ASCII, multidrop, and binary protocols; compressed ASCII commands; Fast Meter/Fast Operate support; Remote control bits for SCADA/RTU functions.