SEL-551/SEL-551C and SEL-851 Comparison

Standard Feature

Model Option

Features

SEL-551
SEL-551C

SEL-851

Display/Front Panel

Graphical LCD Display

Local/Remote Control

Trip/Close Breaker Control

8 Programable LEDs

USB-C Communications Port

CT/PT Inputs

1 A/5 A Software-Selectable Current Inputs

3 Voltage Inputs: VA, VB, VC

Applications

Breaker Failure Protection

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Underfrequency Load Shedding

Undervoltage Load Shedding

Loss-of-Potential Logic

Protection Elements

50AF/50NAF Arc-Flash Detection Instantaneous Overcurrent

27/59 Over-/Undervoltage

32 Directional Power

55 Power Factor

60 Loss-of-Potential

81O/81U Over-/Underfrequency

Second-Harmonic Blocking

Instrumentation and Control

Arc-Flash Detection Inputs

Load/Signal Profile Recorder

Software-Invertible Polarities

Built-In Web Server

Harmonic Metering

RMS Metering

Configuration Software

acSELerator QuickSet SEL-5030 Software

SEL Grid Configurator Software

Programmable Digital Inputs (24–250 Vdc/Vac)

Universal Power Supply (24–250 Vdc/110–240 Vac)

Communications Ports and Protocols

USB-C Port (Front)

Setting-Selectable EIA-232/EIA-485 Port (Rear)

Single 10/100BASE-T Ethernet Port (Rear)

Dual 10/100BASE-T Ethernet Ports (Rear)

Modbus RTU and Modbus TCP/IP

IEC 61850 Edition 2

DNP3 Level 2 (Serial and LAN/WAN)

Simple Network Time Protocol

Common features are not listed in this comparison. For more information, visit the product pages.