Project Description

SEL-411L Advanced Line Differential Protection, Automation, and Control System

SEL-411L Advanced Line Differential Protection
Apply the SEL-411L Relay for complete protection and control of any transmission line. The SEL-411L provides differential protection with both phase- and sequence-based operating elements for sensitivity and high-speed operation. Choose from many popular fiber and multiplexed communications options. Distance protection and logic from a complete SEL-421 Protection, Automation, and Control System are included to provide backup protection and integration. Any transmission line (short, long, or series-compensated) can be well protected with the SEL-411L Relay.

Functional Overview

SEL-411L Functional Overview
21 Phase and Ground Distance
25 Synchronism Check
27 Undervoltage
32 Directional Power
50 Overcurrent
50BF Dual Breaker Failure Overcurrent
51 Time-Overcurrent
59 Overvoltage
67 Directional Overcurrent
68 Out-of-Step Block/Trip
79 Single-/Three-Pole Reclosing
81 (O, U) Over-/Underfrequency
85 RIO SEL MIRRORED BITS Communications
87 Current Differential
DFR Event Reports
ENV SEL-2600
HMI Operator Interface
LGC Expanded SELOGIC Control Equations
MET High-Accuracy Metering
PMU Synchrophasors
SER Sequential Events Recorder
BRM Breaker Wear Monitor
LDE Load Encroachment
LOC Fault Locator
SBM Station Battery Monitor


Front- and Rear-Panel Diagrams

 SEL-411L Front Panel  SEL-411L Rear Panel
 Front  Rear


Line Current Differential, Distance, and Directional Overcurrent Protection

  • Apply single- or three-pole subcycle current differential protection for up to four terminal lines, even with two breakers per terminal.
  • Implement subcycle operation and superior security with five zones of phase and ground distance elements as well as directional overcurrent elements.
  • Reduce protection system costs by stocking one relay for line protection using a combination of the differential, distance, and overcurrent elements to meet your application needs.

Comprehensive Monitoring

  • Validate 87L channel health and enhance trip security by using advanced 87L channel monitoring functions.
  • Incorporate IEEE C37.118 synchrophasor measurements into wide-area protection and control systems.
  • Use high-accuracy time correlation to improve event report analysis.

Advanced Automation and Communication

  • Reduce total project construction and operation costs by integrating four-shot recloser and relay logic to automate operations.
  • Use serial or Ethernet communications to improve station integration.
  • Available protocols include Mirrored Bits communications, DNP3 LAN/WAN, Modbus®, the Simple Network Time Protocol (SNTP), the Parallel Redundancy Protocol (PRP), and IEC 61850.

High-Accuracy Fault Location

  • Find faults fast with the optional traveling wave fault location.
  • Reduce maintenance expenses by sending crews to the tower nearest the fault.
  • Use single- and double-ended impedance-based fault location methods in parallel with traveling wave fault location.



411L 421 311C 311L 387L
Distance Protection
Line Current Differential
Breaker Failure Protection f f
Undervoltage Load Shedding f f f f
Series-Compensated Lines + +
21G Mho Ground Distance
21XG Quad Ground Distance
21P Mho Phase Distance
25 Synchronism Check
27/59 Under-/Overvoltage f
49 Thermal f f
50 (N,G) Overcurrent (Neutral, Ground)
50P Phase Overcurrent
50Q Negative-Sequence Overcurrent
51 (N,G) Time-Overcurrent (Neutral, Ground)
51P Phase Time-Overcurrent
51Q Negative-Sequence Time-Overcurrent
67 (N,G) Directional Overcurrent (Neutral, Ground)
67P Phase Directional Overcurrent
67Q Negative-Sequence Directional Overcurrent
81 Under-/Overfrequency
87L Line Current Differential
Sensitive Earth Fault (SEF)
Programmable Analog Math
Out-of-Step Block and Trip
Load-Encroachment Supervision
Single-Pole Trip + +
Zone/Level Timers
Pilot Protection Logic
79 Automatic Reclosing
Number of Controlled Breakers 2 2 1 1 1
Fault Locating
Traveling Wave Fault Location +
Subcycle Distance Elements + + +
SELogic Control Equations
Nonvolatile Latch Control Switches
SELogic Remote Control Switches
SELogic Local Control Switches +
Display Points +
Mirrored Bits Communications
Substation Battery Monitor
Breaker Wear Monitor
Trip Coil Monitor f f f f
Event Report (Multicycle Data)
Sequential Events Recorder
Instantaneous Meter
DNP3 Level 2 Outstation + +
IEC 61850 Communications + + + +
Synchrophasors (SEL Format)
Synchrophasors (IEEE C37.118 Format)
Accepts Delta Voltage Transformers +
Connectorized (Quick Disconnect) Available + + +
Configurable Labels +
Standard Feature
+ Model Option
f This function may be created using settings

Product Literature