Reliability measurements for gas turbine warranty situations

Abstract

Reliability performance is currently receiving significant attention in the bid requests for new gas turbine generating units. Reliability guarantees backed by liquidated damages clauses are becoming 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 sufficiently refined for the warranty situation. This paper is intended to provide the guidance, structure and refinement needed for meaningful reliability warranties. Four key areas of reliability measurement: starting reliability, running reliability, availability and equivalent availability are separately addressed. And within each of these areas there is the flexibility, the methodology and the need to adapt the measurement system to the varied operating regimes and philosophies encountered such as: peaking vs. continuous service, attended vs. unattended sites, different levels of maintenance intensity, chargeable vs. non-chargeable 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 accuracy, statistical confidence, assurance of readiness and risk assessment. The suggestions presented herein have been constructed with logic and fairness. This paper will be beneficial to all Architect Engineers, Utilities, Independent Power Producers and OEM's that become involved with the structuring of reliability warranties.