Development of a life cycle cost estimating tool to compare GIS and AIS substation projects

Gas-insulated switchgears (GIS) are emerging as more capable power system assets than conventional air-insulated switchgears (AIS), especially in terms of operational reliability and maintenance requirements. However, insufficient consideration is often given to comparing GIS and AIS substation project options. Therefore, a more effective approach is needed to better inform project investment decisions. This paper outlines the development of a project life-cycle cost-estimating software tool for GIS and equivalent AIS substation projects, and formulation of the underpinning economic models. The cost-estimating tool provides practical and objective comparisons between considered GIS and AIS substation projects, and opportunities to investigate major cost contributing factors in substation project cost estimates.