Probabilistic Spare-Equipment Analysis

This chapter discusses the methods of probabilistic spare-equipment analysis and their applications. A spare can reduce the failure probability of an equipment group and thus the failure cost, resulting in economic benefit, but it also requires capital investment. The chapter discusses two methods of spare-equipment analysis. The first one is based on the reliability criteria of an equipment group and the second one on the probabilistic cost model. The second method is more comprehensive since the benefit/cost analysis is conducted, which provides the financial justification for decision making. Two examples are also given in the chapter. The first one is an analysis of offline spare transformers and the second one is an analysis of online redundancy of 500 kV reactors.