Case Study: PacifiCorp achieves faster, more reliable remedial action scheme protection with Schweitzer Engineering Laboratories (SEL) dual TMR control

PacifiCorp’s Jim Bridger RAS A Dual Triple Modular Redundant Case Study

PacifiCorp needed to modernize the remedial action scheme protecting the Jim Bridger Power Plant, a critical coal-fired generation site in Wyoming that moves power over a complex, high-voltage transmission corridor. The existing mix of obsolete TMR PLC and hard-wired relay systems was hard to maintain, difficult to expand, and had to support fast, reliable action to avoid instability and unnecessary generator tripping. PacifiCorp worked with Schweitzer Engineering Laboratories (SEL) to replace the legacy setup with a more maintainable, substation-grade control solution.

Schweitzer Engineering Laboratories (SEL) implemented a dual triple modular redundant RAS built on IEC 61131-3-compatible controllers with high-speed I/O, redundant communications, supervision logic, and a test simulator for validation and maintenance. The new architecture lets the two independent TMR systems vote on actions, coordinate to avoid conflicting trips, and process contingencies in under 17 milliseconds, meeting the 20-millisecond design target. The result was a more deterministic and fault-tolerant scheme that can shed only the necessary generation, improve availability, and requires four specific hardware failures before it can no longer make a decision.

PacifiCorp

Dean Miller

PacifiCorp