SEL-751A and SEL-751 Comparison

Display/Front Panel

5" Color Touchscreen Display, 800 × 480 Resolution

4 Front-Panel Pushbuttons With Tricolor LEDs, Customizable

8 Front-Panel Pushbuttons With Tricolor LEDs, Customizable

CT/PT Inputs

Low-Energy Analog (LEA) Voltage Inputs

Applications

Undervoltage Load Shedding

Protection Elements

27I Inverse Time Undervoltage

49R Resistance Temperature Detector

49T IEC Line/Cable Thermal Overload

50INC Incipient Cable Fault Detection

51G Residual Time-Overcurrent With Directional Control

51N Neutral Time-Overcurrent With Directional Control

51P Max. Phase Time-Overcurrent With Directional Control

51Q Negative-Sequence Time-Overcurrent With Directional Control

59I Inverse Time Overvoltage

67G Residual Overcurrent With Directional Control

67N Neutral Overcurrent With Directional Control

67P Max. Phase Overcurrent With Directional Control

67Q Negative-Sequence Overcurrent With Directional Control

78VS Vector Shift

81 Over-/Underfrequency

FLOC Fault Locator

HBL Second- and Fifth-Harmonic Blocking

HIF AST Arc Sense Technology (AST) High-Impedance Fault Detection

Load-Encroachment Supervision

Instrumentation and Control

Arc-Flash Detection inputs

4

4 or 8

Data Acquisition

16 samples/cycle

32 samples/cycle

Event Report

15 or 64 cycles

15, 64, or 180 cycles

Web Server

Firmware Download Via the Ethernet port

14 Digital Inputs Card Support

Incoming GOOSE Messages Support

16

64

Synchronized Phasor Measurement

Up to 10 messages/second

60 messages/second at 60 Hz

Fault Locator

Bay Control

Communications Protocols

IEC 61850 Edition 2

IEC 60870-5-103

Parallel Redundancy Protocol (PRP)

IEEE 1588 Firmware-Based Precision Time Protocol (PTP)

EtherNet/IP

HTTP