Reliability Report -- 1999 - Pennsylvania Public Utility Commission

PPL’s SAIFI increased from 0.89 in 2009 to 1.09 in 2010, which was a 22.5 percent increase in outage
frequency and 7.9 percent better than the standard of 1.18. SAIFI had remained below the benchmark
from June 2009 through June 2010, but is trending upward, attributable, in part, to storms that are not
excludable. The SAIFI three-year average was 1.01, or 6.6 percent below the standard of 1.08. For the
12-month average ending March 31, 2011, SAIFI was 1.16, or 1.5 percent below the standard. Figure
32 depicts the trend in the frequency of service interruptions for the PPL system from March 2004
through March 2011, compared to the established benchmark and standard for SAIFI.
In 2010, equipment failure represented 27.8 percent of the interruptions, 32.1 percent of customers
affected and 27.4 percent of interruptions minutes. PPL reported that a large portion of interruptions
attributed to equipment failure were weather-related and are not considered to be indicators of
equipment condition or performance. Non-trimming tree-related outages, generally caused by trees
falling from outside of PPL’s rights-of-way, were the second-largest cause of customer outages
representing 27.0 percent of incidents, 33.8 percent of customers affected and 48.4 percent of
interruption minutes. Animal-related outages accounted for 23.6 percent of incidents, 5.3 percent of
customers affected and 4.6 percent of interruption minutes. Figure 33 shows the distribution of causes
of service outages occurring during 2010 as a percentage of total outages. The trend in the number of
outages by the top three major causes is shown in Figure 34.
Figure 31 PPL Customer Average Interruption Duration Index (minutes)
180
170
160
150
140
130
12-month CAIDI
Benchmark
12-month Standard
120
110
Electric Service Reliability in Pennsylvania 2010 33