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. Add the SEL-T400L to your line protection system to dramatically reduce your fault-clearing time, and achieve the many benefits associated with speed.
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) that does not require communications; and a POTT scheme with traveling-wave (TW32) and incremental-quantity (TD32) directional elements over a digital or an analog protection channel. Achieve 1–5 ms trip times, depending on the 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. Use the relay to 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). Contact SEL to obtain a detailed format description as well as tools (such as the preliminary SEL-5611 synchroWAVe MegaScope client software) to experiment with this advanced SEL-T400L functionality.
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).
Testing Made Easy—Requiring only a few protection settings, the SEL-T400L is easy to commission. Apply any standard relay test set for testing the TD21 distance and TD32 directional elements. Use the SEL-T4287 Traveling-Wave Test System for end-to-end testing of the TW87 scheme, the TW32 element, and the traveling-wave fault locator. You can upload ultra-high-resolution current and voltage files (recorded by SEL-T400L Relays in the field or obtained from your transient simulation software) to the SEL-T400L and test the relay by executing a built-in playback.1