EVALUATING SYSTEM RELIABILITY

For a number of decades power system planners have attempted to obtain the right relationship between a power system's reliability, i. e. , its ability to provide a continuous supply to its customers, and its cost. This objective still serves as a major motivation for the development of quantitative techniques for evaluating power system reliability. All three sectors of the system - generation, transmission, and distribution - are of interest. However, the biggest challenge is the transmission sector - which, unlike its generation and distribution counterparts, does not lend itself to straightforward analysis. The application of reliability-evaluation techniques to power systems can be viewed as a five-step process. First, the modes in which the system may fail are defined, and the events that may lead to each such failure identified (steps 1 and 2). The analytical procedure of modeling system failure in terms of these events follows (step 3). Then, in order to make practical application of the model, one must determine its parameters, such as the frequency and duration of equipment outages (step 4). Finally, the model can be applied to the real world, to evaluate the reliability of specific power system configurations, plans, and designs (step 5).