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Schweitzer Engineering Laboratories has released the SEL-487B Bus Differential and Breaker Failure Relay with enhanced Time-Domain Link (TiDL) technology. TiDL is a protection-centered digital secondary system that replaces secondary system copper connections with fiber to decrease costs and increase safety. Its enhanced features include a purpose-built merging unit, data-sharing capabilities and modern configuration software.

As part of its normal functionality, the SEL-487B provides optimized, low-impedance bus differential fault detection by using high-speed, subcycle protection coupled with high-security operation for external faults. It can protect systems with up to 7 three-phase bus terminals with 6 three-phase differential bus zones and 3 independent check zones. The SEL-487B TiDL relay can be applied in a distributed bus protection scheme because TiDL is easily scalable based on the number of bays in a system.

In a TiDL system, a SEL-487B in the substation control house is connected via fiber to an SEL-TMU TiDL Merging Unit located in the yard. The merging unit samples and digitizes analog values from primary equipment and then directly transmits those data via a non-Ethernet protocol to as many as four SEL TiDL relays.

TiDL’s point-to-point architecture and data-sharing capabilities provide application flexibility and strong cybersecurity. In addition, because TiDL does not require Ethernet switches, routers or external time sources, it is simple to implement. SEL Grid Configurator software, which is available with the enhanced TiDL relays, makes configuring and commissioning devices and custom topologies to fit each application easier too. Visit the Support Videos webpage to learn how to configure TiDL devices using Grid Configurator.

Over the course of the next several months, the TiDL model of the SEL-421 Protection, Automation, and Control System will release with these same enhancements and TiDL technology will be added to the SEL-411L Advanced Line Differential Protection, Automation, and Control System. For information on these release dates, contact Lead Product Manager Scott Wenke.

To learn more about TiDL technology, visit the solutions webpage.