Benefits of SEL-751

The SEL-751 Feeder Protection Relay provides a comprehensive combination of protection, fault-locating features,
monitoring, control, and communication in an industrial package.
➤ Standard Protection Features. Protect lines and equipment with an extensive range of protection elements,
including:
➢ Overcurrent elements
➢ Over- and underfrequency elements
➢ Second- and fifth-harmonic current blocking
(inrush blocking)
➢ Demand metering elements
➢ Breaker failure protection
➢ Phase discontinuity detection
➢ Cold-load pickup
➢ Incipient cable fault detection
➢ Frequency component detection
➢ Breaker failure protection
➢ SELOGIC® control equations
➢ Cable or line thermal elements that conform to
the IEC 60255-149 standard
➤ Additional Protection Features. Use the SEL-751 with one of the voltage input options to protect lines and
equipment with rate-of-change of frequency elements, fast rate-of-change of frequency elements, definite-time
and inverse-time over- and undervoltage elements, and load-encroachment and directional power elements. Also
take advantage of the vector shift elements to aid in islanding detection.
➤ Optional Directional Control. Use overcurrent elements with directional control to optimize radial and looped
network protection for lines and equipment. Best Choice Ground Directional Element® logic optimizes directional
element performance and eliminates the need for many directional settings.
➤ Optional High-Impedance Fault Detection. Use the high-impedance fault (HIF) detection element to detect
small current ground faults typically resulting from downed conductors on ground surfaces, such as earth,
reinforced concrete, or other poorly conductive materials. HIF event data are available in COMTRADE or
Compressed ASCII format.
➤ Optional Arc-Flash Protection. Reduce or eliminate damage from arc-flash events with the optional four- or
eight-channel fiber-optic arc-flash detector inputs and protection elements. Settable arc-flash phase and neutral
overcurrent elements, combined with arc-flash light detection elements, provide secure, reliable, and fast arc-flash
event protection.
➤ Optional Broken Conductor Detection. The broken conductor detection (BCD) element identifies highimpedance downed conductors when combined with the Arc Sense™ technology (AST) option on wye-connected
services. This detector operates on three-phase and single-conductor services and can help reduce the possibility of
a public hazard, including fire.
➤ Optional Low-Energy Analog (LEA) Voltage Sensor Inputs, Rogowski Coil/LPCT Currents Inputs, and
Conventional 200 mA Sensitive Neutral Input. The LEA input range for voltages is as high as 8 Vac rms. Based
on the nominal feeder current, the relay automatically sets the gain for the LEA current channel inputs, which
allows for a wide range of primary currents.

➤ Optional Synchronism Check and DC Station Battery Monitor. Check single-phase voltage across a circuit
breaker, measure dc voltage levels in the substation battery, or use as an additional ac voltage measurement with
over- and undervoltage elements.
➤ Operator Controls and Reclosing. Trip and close the breaker easily with four or eight programmable front-panel
pushbuttons, each with two tricolor LEDs. Implement remote and local control functions, and selectively reclose
with synchronism and voltage checks.
➤ Integrated Web Server. View settings and metering and monitoring data, download event reports, and upgrade
relay firmware with an intuitive password-protected web server.
➤ Relay and Logic Settings Software. Reduce engineering costs by using ACSELERATOR QuickSet® SEL-5030
Software for relay settings and logic programming and to simplify development of SELOGIC control equations.
➤ Metering and Monitoring. Use built-in metering functions to eliminate separately mounted metering devices.
Analyze Sequential Events Recorder (SER) reports and oscillographic event reports for rapid commissioning,
testing, and post-fault diagnostics. Unsolicited SER protocol allows station-wide collection of binary SER
messages.
➤ Optional Fault Location. Reduce fault location and repair time with built-in impedance-based fault location and
faulted phase indication.
➤ Wye or Delta Voltage Inputs. Connect voltage inputs that are wye-connected, open-delta-connected, or single
voltage.
➤ Additional Standard Features. Improve your feeder protection with these additional standard features in every
SEL-751: Modbus RTU, Event Messenger support and MIRRORED BITS® communications, load profile and
breaker wear monitoring, support for 12 external RTDs (SEL-2600), IRIG-B input, advanced SELOGIC, and IEEE
C37.118-2005-compliant synchrophasor protocol to provide real-time measurement data.
➤ Optional Communications Protocols. Optional communications protocols include IEC 61850 Edition 2.1,
Modbus TCP/IP, Simple Network Time Protocol (SNTP), IEEE 1588-2008 firmware-based PTP, IEEE 1588-2008
hardware-based PTP when in PRP mode, PRP, EtherNet/IP, DNP3 LAN/WAN, DNP3 serial, IEC 60870-5-103,
and RSTP. With an Ethernet equipped relay, use the integrated web server to view settings and metering and
monitoring data, download reports, and upgrade firmware.
➤ Optional Communications Ports. Elective communications ports include EIA-232 or EIA-485 multimode fiberoptic serial port and single or dual, copper or fiber-optic Ethernet ports.
➤ Optional I/O Cards. Digital and analog I/O options include 4 AI/4 AO, 4 DI/4 DO, 8 DI, 8 DO, 8 AI, 3 DI/4 DO/
1 AO, 4 DI/3 DO, and 14 DI. An optional 10 internal RTD card is also available for the SEL-751. Conformal
coating for chemically harsh and/or high moisture environments is also available as an option.
➤ Supported Languages. Choose English or Spanish for your serial ports, including the front-panel serial port. The
standard relay front-panel overlay is in English; a Spanish overlay is available as an ordering option.