Case Study: PECO Energy Co. achieves highly reliable substation automation with Schweitzer Engineering Laboratories (SEL)

Case Study of a Large Transmission and Distribution Substation Automation Project

PECO Energy Co., a utility serving the Philadelphia area, needed to modernize a deteriorating substation control environment while supporting both a legacy transmission SCADA system and a new distribution automation program. The company wanted a solution with no single point of failure, fast remote control response, and timely metering/status updates, while reducing the cost and wiring burden of its aging RTU-based approach. Schweitzer Engineering Laboratories (SEL) was brought in to help evaluate the options, including microprocessor-based relays and communications processors.

SEL implemented a communications processor star relay network centered on microprocessor-based protective relays, integrated into a substation integration system with redundant primary and backup protection, communications, and local HMI support. PECO reported major benefits: a redundant communications processor star design was 22 times more reliable than a redundant RTU design and 25 times more reliable than a redundant PLC design, while also costing far less than traditional alternatives. The new architecture reduced relays by 75%, analog wiring by 30%, and control wiring by 50%, and PECO ultimately deployed the design across 87 substations.

PECO Energy Co.

Jack Leonard

Supervising Engineer