Time-Domain Line Protection

Apply the SEL-T400L Time-Domain Line Protection for ultra-high-speed protection of transmission lines. With breakthrough time-domain technologies, the SEL-T400L trips securely in as fast as 1 ms, records events with a 1 MHz sampling rate, and locates faults to the nearest tower. Adding the SEL-T400L to your line protection system can dramatically reduce your fault-clearing time and let you achieve the many benefits associated with speed.

Applications

Ultra-High-Speed Tripping With Security—The SEL-T400L features a traveling-wave differential scheme (TW87) over a dedicated point-to-point fiber channel; an incremental-quantity distance element (TD21) and a POTT scheme with traveling-wave (TW32) and incremental-quantity (TD32) directional elements over a digital or an analog protection channel. You can achieve 1–5 ms trip times, depending on the channel, line length, and system conditions.

Simplicity—Requiring only a few protection settings, the SEL-T400L is easy to learn, easy to apply, and easy to set. The relay settings require only very basic short-circuit studies, and the relay settings are greatly resilient to power system evolution and changing short-circuit levels.

High-Fidelity Recording—The SEL-T400L provides high-resolution voltage and current recording with a 1 MHz sampling rate and an 18-bit resolution. You can record and analyze high-frequency transients, such as traveling waves from faults, switching events, breaker restrikes, and self-extinguishing faults. The SEL-T400L also streams time-stamped Fast Time-Domain Values (FTDV).

Accurate and Economical Fault Locating—The SEL-T400L includes traveling-wave fault-locating methods that work with or without communications. The SEL-T400L routinely locates faults within one tower span. The double-ended fault location result is available within a few tens of milliseconds, allowing the SEL-T400L to control autoreclosing depending on the location of the fault (such as in applications on lines with underground cable sections).

Event Playback—You can test the protection and fault-locating functions without a relay test set by using the built-in event playback function and events recorded in the field or simulated using electromagnetic transient programs. With the event playback function, you can trigger a playback test in multiple relays based on time for end-to-end testing of the SEL-T400L protection schemes and multi-ended fault locators.