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5 <br />II. IEEE Statistics <br />When it comes to reliability metrics, the industry standard metrics are defined in the <br />Institute for Electrical and Electronics Engineers’ Guide for Electric Power Distribution <br />Reliability Indices, or IEEE 1366 guidelines. For each utility, the eReliability Tracker <br />performs IEEE 1366 calculations for System Average Interruption Duration Index (SAIDI), <br />System Average Interruption Frequency Index (SAIFI), Customer Average Interruption <br />Duration Index (CAIDI), Momentary Average Interruption Frequency Index (MAIFI) and <br />Average Service Availability Index (ASAI). <br />It is important to note how major events (MEs) are calculated and used in this report. An <br />example of a ME includes severe weather, such as a tornado or hurricane, that leads to <br />unusually long outages in comparison to your distribution system’s typical outage. Both <br />the eReliability Tracker and this report use APPA’s ME threshold, which is a calculation <br />based directly on the SAIDI for specific outage events, rather than daily SAIDI. APPA’s ME <br />threshold allows a utility to remove outages that exceed the IEEE 2.5 beta threshold for <br />outage events, which take up to 10 years of the utility's outage history. In the eReliability <br />Tracker, if a utility does not have at least 36 outage events prior to the year being <br />analyzed, then no threshold is calculated. If this is the case for your utility, then you will <br />have a NULL value in the field below and the calculations without MEs in the SAIDI section <br />of this report will be the same as the calculations with MEs for your utility. More outage <br />history will provide a better threshold for your utility. <br />Your utility's APPA major event threshold is 8.35. <br />For each of the reliability indices, this report displays your utility’s metrics alongside other <br />comparative groups. The first table within each of the following subsections allows you to <br />better understand the performance of your electric system relative to other utilities <br />nationwide and to those within your same region or size class. The second table breaks <br />down the national data into quartile ranges, a minimum value, and a maximum value. <br />253