Unified Reliability Index Development for Utility Performance Assessment

The major purpose of the continuous development of reliability indices is to capture a comprehensive view of systems performance. The lack of consensus among utilities and regulators on which indices should be used complicates the problem more. Regulators inevitably make comparisons between utilities’ routinely reported reliability indices. Thus, an adequate and fair process needs to be implemented. Utilities are reporting indices in a chaotic way. One utility might report SAIFI and SAIDI, while others report SAIFI and CAIDI. In this work, a development of a unified reliability index, which can yield proper performance assessment, fair comparisons, and reflection of all the knowledge embedded within all current indices, will be formed. The initiated unified index may provide several benefits, among which is suitable standards design, improved tools for planning and design optimization, and less technical burden on operators. Also, the development of a unified reliability index requires the initiation of a standard normalization methodology based on a maximum that takes into account the variation between systems under study. After normalization, combining indices is made possible through a proposed methodology. The developed methodology is validated by comparing it to both simple averaging technique and a fuzzy inference based engine.