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    SEL-T400L

    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. Add the SEL-T400L to your line protection system to dramatically reduce your fault-clearing time, and achieve the many benefits associated with speed.

    Starting At

    12,000 USD

    Learn More About the SEL-T400L

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    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

    1Coming soon

    Overview

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    Videos

    Announcing SEL-T400L Time-Domain Line Protection

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    Announcing SEL-T400L Time-Domain Line Protection

    Speed. Security. Simplicity. SEL-T400L

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    Speed. Security. Simplicity. SEL-T400L

    How to Set the SEL-T400L

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    How to Set the SEL-T400L

    Protection Applications
    Apply the SEL-T400L to a variety of line and system configurations, including:

    • POTT and distance protection for two-, three-, and four-terminal lines over a digital channel, analog channel, or direct-fiber channel
    • TW87 protection for two-terminal lines with a provision for unmeasured taps, over a digital channel, analog channel, or direct-fiber channel
    • Built-in direct transfer tripping (DTT)
    • Single-pole tripping
    • Series-compensated lines
    • Lines with line-side and bus-side reactors
    • Hybrid lines with overhead and underground cable sections
    • In-line CTs and breaker CTs in dual-breaker applications with per-breaker current measurement
    • High-speed trip-rated outputs for two breakers and single-pole tripping

    Hassle-Free Installation
    Use the SEL-T400L with standard control cables and wiring to connect to conventional current and voltage transformers, including coupling capacitor voltage transformers (CCVTs), and directly to breaker trip-coil circuits. The relay uses current traveling waves, and these waves are adequately measured with standard CTs and cabling. The relay uses the very first voltage traveling wave in the TW32 directional element, and this wave is reproduced correctly by many CCVTs or not reproduced at all, guaranteeing security of the TW32 element. Use Mirrored Bits communications to signal local devices for breaker failure protection and autoreclose control applications and to signal remote SEL-T400L Relays in POTT and DTT applications.

    Relay Configuration and Settings
    Designed with simplicity in mind, the SEL-T400L uses simple multiple-choice user preferences to accommodate a wide array of applications without the need to write custom logic equations. The protection elements and schemes have very few or no settings at all in addition to the customary enable and overcurrent supervision settings. The vast majority of protection settings are nameplate data, such as current and voltage transformer ratios, line parameters, nominal voltage, or system frequency and phase rotation. These settings are easy to set and do not need to be reevaluated as the power system evolves and the short-circuit levels change.

    Fault-Locating Applications
    Trigger fault locating for line faults from the SEL-T400L protection or from external relays in redundant protection applications or in standalone fault-locating applications. SEL-T400L fault-locating highlights include:

    • Fault locating for two-terminal lines that is accurate to a single tower span based on traveling waves from one or both ends of the line
    • Double-ended traveling-wave fault locating for nonhomogeneous hybrid lines with overhead and underground cable sections
    • Double-ended fault-locating result that is available in milliseconds, allowing the SEL-T400L to control autoreclosing based on the location of the fault
    • Built-in fallback to single- and double-ended impedance-based fault-locating methods for dependability of fault locating during faults at the voltage zero crossing
    • Support for off-line traveling-wave fault locating for multiterminal lines

    Digital Fault-Recording Applications
    SEL-T400L recording highlights include:

    • High-fidelity (1 MHz, 18-bit) time-stamped sampling with the frequency response up to about 400 kHz
    • Programmable trigger for standalone recorder applications
    • Recording duration of up to 1.2 seconds per record
    • Storage for up to 50 1.2-second events
    • Back-to-back recording capability for the total length of up to 3.6 seconds (3 records)
    • Local voltages and individual breaker currents
    • Time-aligned remote voltages and line currents if the dedicated point-to-point fiber channel is used
    • Ultra-high-resolution records (1 MHz analogs) for analysis of power system events and of traveling-wave protection and fault-locating functions
    • High-resolution records (10 kHz analogs and digitals) for analysis of protection functions
    • IEEE COMTRADE (2013 version) file format
    • TCP/IP File Transfer Protocol (FTP) over a Gigabit Ethernet port for fast access to the large record files
    • Streaming FTDV over a Gigabit Ethernet port for wide-area high-fidelity event recording and continuous monitoring

    Product Certifications

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