html{display:none} SEL-421 Protection, Automation, and Control System - Specifications | Schweitzer Engineering Laboratories


AC Current Inputs (6 total)
5 A nominal
1 A nominal
AC Voltage Inputs (6 total)300 VL-N continuous, 600 Vac for 10 seconds
Serial1 front-panel and 3 rear-panel EIA-232 serial ports
300—57,600 bps
EthernetCommunications protocols include FTP, Telnet, synchrophasors, DNP3 LAN/WAN, PRP, PTPv2, and IEC 61850 Edition 2 (optional).
Choose from the following port options:
  • Two 10/100BASE-T twisted-pair network ports
  • Two 100BASE-FX fiber-optic network ports
  • One 10/100BASE-T twisted-pair network port and one 100BASE-FX fiber-optic network port
TiDL PortsFiber-optic ports: 8
Range: ~2 km
Data rate: 100 Mbps
Protocol: SEL T-Protocol
SV PortsChoose from the following communications port options:
  • Four 10/100BASE-T twisted-pair network ports
  • Four 100BASE-FX fiber-optic network ports
  • Two 10/100BASE-T twisted-pair network ports and two 100BASE-FX fiber-optic network ports
Subscriber: As many as 7 SV data streams
Publisher: As many as 7 SV data streams
Data rate: 80 samples per cycle
Protocol: IEC 61850-9-2
Precise-Time InputDemodulated IRIG-B time input and PTPv2
SynchrophasorsIEEE C37.118 Standard
Up to 60 messages per second
ProcessingAC voltage and current inputs: 8,000 samples per second
Protection and control processing: 8 times per power system cycle
Power Supply24-48 Vdc
48-125 Vdc or 110-120 Vac
125-250 Vdc or 110-240 Vac
Operating Temperature-40° to +85°C (-40° to +185°F)
Note: LCD contrast is impaired for temperatures below -20°C (-4°F) and above +70°C (+158°F).