Substation reliability and economic analysis - Tractebel Choctaw Project

Recent trends are making the AIS (air insulated switchgear) vs. GIS (gas insulated switchgear) decision quite a bit more complicated than it was only a couple of years ago. Tractebel Power Company together with ABB Inc. deployed a unique analytical method to arrive at the decision to deploy a 500 kV gas insulated substation near Ackerman, Mississippi, and to optimize its economic life cycle cost. The switchyard is being constructed to interconnect three generators and one transmission line at Tractebel's new 650 MW combined cycle power plant, the Choctaw Gas Generation Project. This analysis accounted for all the key life cycle costs critical to any power producer, and utilized the latest available quantitative information on GIS/AIS reliability, maintenance, land acquisition, site preparation costs and initial purchase costs. This analysis also accounted for "intangibles" such as safety, aesthetics and security that are often overlooked but becoming increasingly important.