Survey Questions - Edison Electric Institute
Survey Questions - Edison Electric Institute
Survey Questions - Edison Electric Institute
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Chapter 3: The Reliability of Overhead and Underground <strong>Electric</strong>al Systems<br />
Customer Average Interruption Duration Index (CAIDI)<br />
CAIDI is defined as the average length of an interruption experienced by an interrupted customer, measured<br />
in “minutes.” In this index, a customer can be counted as many times as they experience an outage. Figure<br />
3.1, Customer Average Interruption Duration Index, presents the average CAIDI value for 2004 to 2011, for<br />
transmission and distribution combined, and distribution alone. The data demonstrates that the underground<br />
system has a slight advantage over the overhead system in five of eight years for the combined T&D<br />
reporting and seven of eight years for the D only data.<br />
Minutes<br />
450<br />
400<br />
350<br />
300<br />
250<br />
200<br />
150<br />
100<br />
50<br />
0<br />
18 <strong>Edison</strong> <strong>Electric</strong> <strong>Institute</strong><br />
Figure 3.1 Customer Average Interruption Duration Index<br />
2004 2005 2006 2007 2008 2009 2010 2011<br />
OH T&D UG T&D OH D UG D
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