Operational reliability: objective or constraint?

"Should power system operational reliability be treated as an objective or a constraint" is an interesting topic, which can be debated in different frameworks for power system applications. Different frameworks are based on probabilistic models and data, which are necessary for operational reliability analyses. The restructuring of electric power systems has presented a new venue for operational reliability studies. The operational reliability function, which was handled previously by vertically integrated utilities, is delegated to the ISO and conceivably monitored by self interested power companies (i.e., GENCOs). The author argues in this presentation that, depending on the model and application, the reliability equation can represent either a constraint or an objective. The discussion here focuses on a specific power system application (e.g., generation maintenance scheduling), which shows the impact of incorporating operational reliability constraints in scheduling the maintenance of generating units.