Pend Oreille Utility Benefits From Innovative RTU Upgrade Strategy

Pend Oreille Public Utility District’s remote terminal units (RTUs) were nearing the ends of their useful lives. The nearly 20-year-old analog and digital devices needed to be replaced at all six of the utility’s substations. The utility appeared to have two options: a costly module upgrade of the existing RTUs (which would introduce unwanted complexity) or replacement of all the system’s field wiring (a daunting task and a major expense).

Customer Profile

Customer: Pend Oreille Public Utility District (PUD)

Location: Pend Oreille County, Washington State

Industry: Electric Utility

Application: Automation Modernization

“We were really traveling down the path of just...getting a (module) upgrade to this particular RTU,” said Mike Boyle, System Protection/SCADA Engineer at Pend Oreille PUD.

That’s when SEL contacted them with a compelling offer: a system that would retain all their existing field wiring while replacing the aging RTU infrastructure with a powerful SEL Real-Time Automation Controller (RTAC).

“We were two-thirds of the way into the process of replacing our existing RTU structure,” said Mike, “so we just put that on hold and said, ‘all right, let’s give these guys a shot.’”

The new system pairs the powerful computing of an SEL RTAC with SEL-2240 Axion modular I/O and custom cabling. The Axion gathers a vast quantity of analog data and statuses, including previously unavailable data, to provide a complete picture of the Pend Oreille PUD system. The RTAC then processes the data and delivers the information to the SCADA master.

The custom cabling was the key to retaining the existing field wiring. “We developed a cabling solution for them that would...intercept the field wiring without any modifications and make it a simple plug-and-play solution,” said SEL Development Lead Engineer Robert Schloss.