Product Comparison

Distribution Feeder Protection Features

Features SEL-451 SEL-351 SEL-351A SEL-351S SEL-851 SEL-751 SEL-751A SEL-501


Distribution Protection—Applications
Distribution Feeder Protection
BF Breaker Failure Protection
Generator Intertie Protection
25 Synchronism Check
Underfrequency Load Shedding ƒ
Undervoltage Load Shedding ƒ
27/59 Under-/Overvoltage
32 Directional Power Elements ƒ
49 IEC Line/Cable Thermal Overload ƒ        

50 (P,N,G,Q) Overcurrent Element
(Phase, Neutral, Ground, Neg. Seq.)

51 (P,N,G,Q) Time-Overcurrent Element

(Phase, Neutral, Ground, Neg. Seq.)

67 (P,N,Q) Directional Overcurrent

(Phase, Neutral, Neg. Seq.)
78VS Vector Shift          
81 Over-Underfrequency
Separate Neutral Overcurrent
Load-Encroachment Supervision
Low-Energy Analog (LEA) Voltage Inputs

Directional Sensitive Earth Fault Protection
Pilot Protection Logic

81R User Rate-of-Change-of-Frequency (df/dt)
81RF Fast Rate-of-Change-of-Frequency ƒ        
Harmonic Blocking

Arc Sense Technology (AST)

High-Impedance Fault Detection
Arc-Flash Detection        
Phantom Phase Voltage  
Current/Voltage Channels 6/6 4/4 4/4 4/4
4/0 Standard

4/3 Optional

4/3 Standard

4/5 Optional

4/0 Standard

4/5 Optional
6/0 4/0
Complete Two-Breaker Control
Instrumentation and Control
79 Automatic Reclosing
Fault Locating

SELogic Control Equations

With Remote Control Switches
SELogic Counters
Voltage Check on Closing
SELogic Nonvolatile Latch
Nonvolatile Local Control Switches
Substation Battery Monitor
Breaker/Recloser Wear Monitor
Trip Coil Monitor ƒ ƒ ƒ ƒ   ƒ ƒ   ƒ

Voltage Sag, Swell, and Interruption (VSSI)
Load/Signal Profile Recorder
Sequential Events Recorder
Software-Invertible Polarities
IEC 60255-Compliant Thermal Model
DNP3 Level 2 Outstation
Parallel Redundancy Protocol (PRP)

IEEE 1588 Precision Time Protocol Version 2 (PTPv2)

Time-Domain Link (TIDL) Technology
IEEE C37.118 Synchrophasors
Bay Control
Built-In Web Server
IEC 61850
IEC 61850 Edition 2
IEC 61850-9-2 Sampled Values Technology

Firmware Option With Mirrored Bits Communications Available
Simple Network Time Protocol (SNTP)
Harmonic Metering  
RMS Metering

 Standard Feature

 Model Option

ƒ This function can be programmed using logic

Questions? Contact Us!

If you have any questions about SEL products, services, solutions, or support, please contact us. Our service and support professionals are ready to provide the answers you need.

Unbeatable Support

SEL support teams are stationed in regional offices around the world and staffed with application engineers who are experts in our products and in power system applications.

Technical support for SEL-manufactured devices is always free. No matter how often you need to call or how long your SEL products have been in service, you’ll reach an SEL expert who can provide the service and support you need.

Our cybersecurity team is always ready with the information and resources needed to keep your OT networks and critical systems secure and working effectively. Cyber services support contracts can include incident response, audits, system hardening, and more, depending on your anticipated needs.

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