Delivery point reliability measurement

Reliability is one of the most important criteria which must be taken into consideration during the planning, designing and operating phases of any industrial, commercial or utility power system. Two distinct reliability assessment methodologies are frequently used to evaluate the reliability performance of power systems: 1) historical reliability assessment, i.e. the collection and analysis of system outage data; and 2) predictive reliability assessment, i.e., combining historical outage data and theoretical models to estimate the performance of various power system operating configurations. This paper focuses on the historical assessment of the sustained frequency and duration of single-circuit and multi-circuit delivery point interruptions. Delivery point reliability levels have a significant impact on the design of industrial and commercial power systems (e.g., IEEE Gold Book-IEEE Standard 493). Bulk electricity system average reliability performance indices are defined and statistics based on delivery point sustained interruption data for a five year period from 1988 to 1992 are presented and discussed in detail in this paper.