Change List for this Rule



General Order 166



Standard 12.

Restoration Performance Benchmark For A Measured Event


The Commission shall perform a review of utility performance following every Major Outage.  This standard sets a benchmark for the Commission to use in reviewing utility restoration performance only during Measured Events.






A utility’s restoration performance during a Measure Event shall be presumed reasonable if the CAIDI is 570 or below, and presumed unreasonable if the CAIDI is above 570.  These presumptions are rebuttable.




CAIDI Calculation


CAIDI stands for Customer Average Interruption Duration Index and is computed using the following equation:


total customer minutes of interruption

total number of customer interruptions


If a single customer experiences more than one sustained interruption during a Measured Event, each interruption shall count as a separate customer interruption.  CAIDI shall be measured from the beginning of the Measured Event and shall continue until all customers experiencing interruptions during the Measured Event have been restored.




Transmission Outages


Customer minutes of interruption caused by outages of Transmission Facilities owned by the utility during a Measured Event are included in the calculation of CAIDI for purposes of this standard.


Customer minutes of interruption attributable to utility compliance with ISO directives, including its protocols, tariffs, transmission agreements or other written or verbal instructions specific to the event, which prevent the utility from restoring service it is otherwise able to provide shall be excluded in the calculation of CAIDI for purposes of this standard.





Utilities with fewer than 150,000 electric customers are exempted from application of this standard.