CAIFI explained

The Customer Average Interruption Frequency Index (CAIFI)^[1] is a popular reliability index used in the reliability analysis of an electric power system.^[2] It is designed to show trends in customers interrupted and helps to show the number of customers affected out of the whole customer base.

CAIFI = (TotalNumberofCustomerInterruptions)/(NumberofDistinctCustomersInterrupted)

Notes and References

1. Web site: Distribution System Reliability Evaluation. Sree. Yeddanapudi. Iowa State University. 18 June 2011. dead. https://web.archive.org/web/20111226034249/http://www.ee.iastate.edu/~jdm/ee653/DistributionReliabilityPredictive.ppt. 26 December 2011.
2. https://books.google.com/books?id=9EShPwTRnoUC&dq=caifi+%22four+most+popular%22&pg=PA112 Power Distribution Planning Reference Book, H. Lee Willis, published by CRC Press, 2004, page 112