1.13
Date Code 20100129 Instruction Manual SEL-751A Relay
Introduction and Specifications
Models, Options, and Accessories
➢ Operator control interface
➢ EIA-232 port
➤ Power supply card with two digital inputs and three digital
outputs (Slot A)
➤ Processor and communications card (Slot B)
➢ EIA-232 serial port with IRIG-B time code input
➤ Three expansion slots for optional cards (Slots C, D, E)
➤ Four ac current inputs card (Slot Z)
➤ Protocols
➢ Modbus
®
RTU
➢ SEL ASCII and Compressed ASCII
➢ SEL Fast Meter, Fast Operate, Fast SER, Fast Message
➢ Ymodem File Transfer
➢ SEL MIRRORED BITS
®
➢ Event Messenger
®
➢ Synchrophasors with C37.118
➤ Breaker Wear Monitoring
Options
➤ Firmware option
➢ Autoreclosing Control
➤ Voltage Options (see Tab le 1.1)
➤ Input/Output (I/O) Option
➢ Additional digital I/O
➢ Additional analog I/O
➢ 10 RTD inputs
➤ Communications Options (Protocol/Ports)
➢ EIA-485/EIA-232/Ethernet ports (single/dual, copper
or fiber-optic)
➢ Multimode (ST
®
) fiber-optic serial port
➢ Modbus TCP/IP protocol
➢ DeviceNet
➢ IEC 61850 Communications
➢ DNP3 serial and LAN/WAN
Table 1.1 Voltage Input Options (Sheet 1 of 2)
Voltage Input Options
Option (71)
SEL
ECT
3AVI
a
Option (72)
SEL
ECT
5AVI
b
Option (73)
SEL
ECT
5AVI
c
Option (74)
SEL
ECT 3AVI/
4AFDI
d
Under- and overvoltage
elements (27, 59)
xx x x
Voltage based frequency
measurement and track-
ing
x x x x
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