ELECTRIC SYSTEM RELIABILITY
The utility reliability performance is measured using two standards, the Average Customer Minutes of Interruption (ACMI) and the Outage Frequency. The ACMI measures customer service interruptions in terms of the average minutes of service interruptions per customer. This measure excludes all interruptions from events that produce an impact on system wide ACMI of more than five minutes. The ACMI measure is calculated using the average ACMI for two successive years. The Commission adopted an ACMI performance standard of 59 minutes for 1997 with a symmetrical deadband of 6 percentage points, where no reward or penalty is assessed. In addition, the adopted ACMI performance standard decreases two minutes annually through 2001. Since the ACMI measure requires a two-year average, 1998 is the first year the reliability performance component of the PBR mechanism is applied.
SCE reports for 1998 a two-year ACMI rolling average of 60 minutes, based on an adjusted average ACMI of 56 minutes for 1997 and 65 minutes for 1998. According to SCE this two-year ACMI measure excludes approximately 2,000 interruptions (out of 32,000 interruptions) that occurred in 1997 and 1998 due to "catastrophic events" that resulted in a system wide ACMI of more than five minutes. SCE total recorded ACMI for 1998 is 79 minutes, without the adjustment. SCE then subtracted 8.5 minutes for a February 3rd rain storm and 5.5 minutes for a December 9th wind storm. For 1997 SCE total recorded ACMI is 78 minutes less 22 minutes for a windstorm in January 6th and 7th of that year. Energy Division confirmed these outages and finds SCE's ACMI calculations correct. Therefore, no reward or penalty is assessed for 1998 given that SCE's two-year ACMI is 60 minutes which falls within the deadband adopted by the Commission.
The Outage Frequency measures the number of circuit interruptions excluding all interruptions that have a duration of more than five minutes. The Outage Frequency rating is also measured using a two-year average. The Commission adopted an outage frequency standard were SCE is penalized if the outage frequency is above 12,000 and rewarded if it is below 9,800.
SCE reports a two-year outage frequency average of 9,450 based on an adjusted outage frequency of 8,987 and 9, 913 for 1997 and 1998, respectively. SCE total outage frequency for 1997 is 9,907 less 920 interruptions for January 6th and 7th windstorm. SCE total outage frequency for 1998 is 10,705, less 456 interruptions for the February 3rd rain storm and 336 interruptions for the December 9th wind storm. Energy Division has reviewed and confirmed SCE's calculations therefore based on an outage frequency of 9,450 and the Commission adopted standard, SCE earned a reward of $2 million for 1998.
