Report of Joint AIEE-EEI Subject Committee on Line Outages [includes discussion]

The Subject Committee on Line Outages was formed jointly in 1947 by the Transmission and Distribution Committees of the Edison Electric Institute (EEI) and the AIEE to obtain fundamental operating data of transmission line outages. Previous line outage studies have considered special aspects of the subject. The present survey is intended to consider all types of line outages over a broad range of system voltages. The primary objectives are: 1. To obtain fundamental data as to the causes of present-day transmission line outages. 2. To correlate the cause of outages with the transmission line and system characteristics. 3. To summarize this information so as to provide assistance for transmission line design and operation. The scope of this survey is limited to overhead transmission circuits. The data used in the line outage study have been submitted by 62 operating companies which are classified in seven regions. The line outage report considers the physical data and line performance records of 689 transmission lines having a total of 33,796 miles of transmission line above 100 kV and embraces 236,666 mile-years of operating experience. These data are shown in detail in tabular form.