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.
Differential Protection Relays
The sensitive differential elements in these protective relays provide subcycle operating times and can be applied on multiterminal 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
| Features | SEL-T401L | SEL-411L | SEL-421 | SEL-311C | SEL-311L | SEL-387L | SEL-T400L |
|---|---|---|---|---|---|---|---|
| Applications | |||||||
| Distance Protection | |||||||
| Line Current Differential | |||||||
| Breaker Failure Protection | ƒ | ƒ | |||||
| Undervoltage Load Shedding | 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 | |||||||
| 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 | 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