html{display:none} SEL-851 Feeder Protection Relay - Specifications | Schweitzer Engineering Laboratories


AC Current Inputs5 A or 1 A phase and 5 A or 1 A neutral (setting-selectable)
AC Voltage Inputs300 Vac continuous, 600 Vac for 10 seconds
Inputs/OutputsStandard includes 4 digital inputs, 5 digital outputs (1 Form C, 2 Form A Standard, 2 Form A Hybrid)
Digital Inputs Wetting4 internally wetted (24 Vdc) digital inputs
Externally wetted universal binary digital inputs (24–250 Vdc/Vac; setting-selectable)
Frequency and Phase RotationSystem frequency: 50, 60 Hz
Phase rotation: ABC, ACB
Frequency tracking: 15–70 Hz
Arc-Flash Time-Overlight Elements (TOL1–TOL4)Pickup time: 1 ms (including output operation when hybrid contact is used)
Dropout time: 16 ms
Communications ProtocolsStandard protocols include SEL protocols, Modbus RTU, Modbus TCP, Mirrored Bits communications, Telnet, the File Transfer Protocol (FTP), TCP/IP, HTTP/HTTPS web server communications, and the Simple Network Time Protocol (SNTP). Optional protocols include IEC 61850 Edition 2 and DNP3 serial and LAN/WAN.
Communications PortsUSB-C front-panel port
10/100BASE-T single or dual Ethernet rear port
EIA-232/EIA-485 rear port with IRIG-B
Universal Power Supply24–250 Vdc/110–240 Vac
Operating Temperature–40° to +85°C (–40° to +185°F)