Case Study: Chattanooga Electric Power Board restores power faster with SEL subtransmission automation

System-Wide Automation Solution Prolongs Life of Existing Relays

Chattanooga Electric Power Board (EPB), a utility serving more than 600 square miles in Chattanooga, Tennessee, needed a more dependable subtransmission system that could restore power faster after outages. Working with Schweitzer Engineering Laboratories (SEL), EPB set out to automate its 46 kV network while still using existing electromechanical relays, which required a solution that could bridge older protection equipment with modern automation.

SEL implemented approximately 100 motor-operated switch controls, SEL-700GT Generator Protection Relays in custom pole-mounted cabinets, SEL-2411 Programmable Automation Controllers, and SEL-351S Protection Systems, all coordinated by SEL-3530 Real-Time Automation Controllers acting as distribution automation controllers. SEL also created an RTU-based interface so the new central automation system could communicate with EPB’s legacy relays. As a result, EPB can now automatically locate, isolate, and restore faults across its subtransmission system, bringing most customers back online faster and giving operators better visibility into which areas need field repairs.

Chattanooga Electric Power Board (EPB)

Don Nanny

Senior Manager of System Analysis and Control