A comparison of four-state generating unit reliability models for peaking units

A peaking unit is different from a base load unit in that it resides most of the time in the available but not operating (ABNO) state. The conventional unit unavailability index is the forced outage rate (FOR) and is based on a two-state model. This model is not suitable for intermittent operating unit representation and results in an unreasonably high unavailability index estimate for a peaking unit. Three four-state models, which recognize the intermittent operating characteristics of a peaking unit, are introduced and compared in this paper.