Line Protection

SEL transmission line protection relays provide subcycle line differential and multizone distance protection for a secure, reliable, and high-speed solution. Their fault-locating capabilities allow you to efficiently dispatch line crews to quickly isolate line problems and restore service faster.

Distance Protection Relays

These phase and ground distance and directional protection relays can be applied for single- and three-pole tripping schemes, compensated lines, or uncompensated lines.

Ultra-High-Speed Protection Relays

These ultra-high-speed transmission line relays built with the time-domain technology of traveling waves and incremental quantities are designed for speed, security, and ease of use.

System Components

Combining these components with line protection relays expands their functionality and simplifies testing.

Transmission and Subtransmission Features

Standard Feature

Model Option

ƒ This function may be created using settings

Features

SEL-T401L

SEL-411L

SEL-421

SEL-311C

SEL-311L

SEL-387L

SEL-T400L

SEL-787L

Applications

Distance Protection

Line Current Differential

Breaker Failure Protection

Undervoltage Load Shedding

Series-Compensated Lines

Protection

Subcycle Distance Elements

21G Mho Ground Distance

21G Quad Ground Distance

21P Mho Phase Distance

21P Quad Phase Distance

TD21 Incremental-Quantity Distance (Phase and Ground)

TD32 Incremental-Quantity Directional

TW32 Traveling-Wave Directional

TW87 Traveling-Wave Differential

87L Line Current Differential

25 Synchronism Check

27/59 Under-/Overvoltage

49 Thermal

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

Programmable Analog Math

Out-of-Step Block and Trip

Load-Encroachment Supervision

Switch-Onto-Fault

Single-Pole Trip

Zone/Level Timers

Pilot Protection Logic

Instrumentation and Control

79 Automatic Reclosing

Number of Controlled Breakers

2

2

2

1

1

1

2

Fault Locating

Single-Ended Traveling-Wave Fault Locating 

Double-Ended Traveling-Wave Fault Locating 

Adaptive Autoreclose Cancel Logic for Hybrid Lines

Line Monitor 

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

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Event Records (Multicycle Data)

1 MHz Sampling Event Records

Sequential Events Recorder

Instantaneous Metering

DNP3 Level 2 Outstation

Parallel Redundancy Protocol (PRP)

IEEE 1588 Precision Time Protocol Version 2 (PTPv2)

IEC 61850-9-2 Sampled Values Technology

Time-Domain Link (TiDL™) Technology

IEC 61850 Communications

Synchrophasors

Built-in Event Playback Testing

SEL Fast Time-Domain Values

Miscellaneous Features

Connectorized (Quick Disconnect) Available

Configurable Labels

Custom Labels