Reliability/availability guarantees of gas turbine and combined cycle generating units

This paper is an updated and revised version of the 1992 ASME paper 92-GT-208 “Reliability measurements for Gas Turbine Warranty Situations” It recognizes that reliability performance is receiving significant and increasing attention in the bid requests for new gas turbine generating units. Reliability guarantees backed by liquidated damages clauses are becoming more the rule rather than the exception. But the power generation industry does not have a universally accepted set of reliability measurements and the more commonly used measurements are not always used appropriately neither are they sufficiently refined for the warranty situation. This paper is intended to provide the guidance, structure and refinement needed for meaningful reliability measurements and reliability warranties. Four key areas of reliability measurement: starting reliability, running reliability, availability and equivalent availability are discussed. Within each of these areas there is the flexibility and the need to adapt the measurement system to the varied operating regimes and philosophies encountered such as: peaking vs. continuous service, limited scopes of supply, different levels of maintenance intensity, chargeable vs. nonchargeable outage events and emotional/political/optical acceptability (i.e. 3% forced outage factor vs. 40% forced outage rate). Warranty structuring rationale and suggested contract language are provided to address such needs as a rigorous and explicit operating log, certification of data, measurement uncertainty, assurance of readiness and risk assessment