SEL transmission protection solutions provide complete primary and backup protection from all types of faults. Using these devices helps you avoid expensive equipment damage and failure while maintaining system performance and increasing availability.
Line Protection
SEL transmission line protection relays provide subcycle line current differential and multizone distance protection, and their application is scalable for your needs.
Time-Domain Protection
Time-domain protection relays use a combination of traveling-wave and incremental-quantity protection technologies to achieve ultra-high-speed tripping.
Transformer Protection
SEL devices protect valuable transformers in power transmission systems.
Busbar Protection
Protect busbars and switchgear with high-speed differential fault detection, or expand your protection with features such as restricted earth fault, arc-flash, and overcurrent elements.
Capacitor Bank Protection
Capacitor protection and controls increase power efficiency and reliability by improving the system’s power factor and voltage stability.
Digital Secondary System Solutions
Time-Domain Link (TiDL) technology and SEL Sampled Values (SV) technology help protect and control substation primary equipment using digital devices in the secondary system that transmit data via fiber-optic cables.
Remote I/O
Remote I/O modules transfer data from remote locations over fiber and expand the I/O of SEL relays, automation controllers, and other devices without modification to the control panel face.
Configuration and Visualization Software
SEL software helps you optimize the configuration of your device and visualize power system events.
Panels and Enclosures
Pre-engineered or custom panels and enclosures help keep costs low and increase system reliability when used for retrofit upgrades and new equipment installations.
Installation Support
Complete your project with power supplies, switches, panel-mount hardware, cables, and other accessories.
Transmission and Subtransmission Features
| Features | SEL-T401L | SEL-411L | SEL-421 | SEL-311C | SEL-311B | SEL-311A | SEL-311L | SEL-387L | SEL-T400L | SEL-321 |
|---|---|---|---|---|---|---|---|---|---|---|
| Applications | ||||||||||
| Distance Protection | ||||||||||
| Line Current Differential | ||||||||||
| Breaker Failure Protection | ƒ | ƒ | ƒ | ƒ | ƒ | |||||
| Undervoltage Load Shedding | ƒ | ƒ | ƒ | ƒ | ƒ | ƒ | ƒ | |||
| 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 | ƒ | ƒ | ||||||||
| 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 | ƒ | ƒ | ||||||||
| Number of Controlled Breakers | 2 | 2 | 2 | 1 | 1 | 1 | 1 | 1 | 2 | 1 |
| 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 | ƒ | ƒ | ƒ | ƒ | ƒ | ƒ | ƒ | |||
| 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 | ||||||||||
| Accepts Delta Voltage Transformers | ||||||||||
| Connectorized (Quick Disconnect) Available | ||||||||||
| Configurable Labels | ||||||||||
| Custom Labels | ||||||||||
Standard Feature
Model Option
ƒ This function may be created using settings