ABSTRACT
Power system availability is defined as the proportion of time that the system is actually available to meet the demands of the customer. Availability is one of the measures of determining the quality of power supply. The absolute values of availability required or expected are very high—99.98% for domestic customer and 99.996% for commercial consumers in most advance countries. To achieve this level of availability, excellent design and maintenance procedure is required. Resilient design requires the intelligent disposition of inherently reliable equipment in a redundant topology, coupled with well-defined and rigorously implemented maintenance procedures [1]. The basic requirement of high reliability of individual units is discussed in this chapter.
