Skip to Main Content
The frequency and duration of the various types of transmission-line outages have a significant impact on the operation and reliability of industrial and commercial power systems. Knowledge of the statistical characteristics of transmission-line outages (e.g., types of faults: three phase, line-to-ground, etc.) directly affects the protection and coordination practices at these facilities. Reliability modeling of industrial and commercial power systems is dependent upon transmission-line outage characteristics (e.g., terminal- and line-related sustained outages). Generalizations of transmission-line characteristics for all voltage classes can be incorrect and extremely problematic in many cases. This paper presents the sum of the results of a ten-year study of the Mid-Continent Area Power Pool transmission-line outage-data statistics for 230-, 345-, and 500-kV lines. These data can be used for modeling the reliability of industrial and commercial facilities being serviced by transmission lines and reveal some of the common beliefs and misconceptions about transmission-line characteristics.