4.1. ERMUSR 03-17-2015 - Laserfiche WebLink

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II. IEEE Statistics When using reliability metrics, a good place to start is with the industry standard metrics found in the IEEE 1366 guide. For each individual utility, the eReliability Tracker performs IEEE 1366 calculations for System Average Interruption Duration Index (SAIDI), System Average Interruption Frequency Index (SAIFI), Customer Average Interruption Duration Index (CAIDI), Momentary Average Interruption Frequency Index (MAIFI) and Average Service Availability Index (ASAI). When collecting the necessary data for reliability indices, utilities often take differing approaches. Some utilities prefer to include information as detailed as circuit type or phases impacted, while others include only the bare minimum required. In all cases, the more details a utility provides, the more practical their analysis will be. As a basis for calculating these statistics in the eReliability Tracker, the following are required to create an outage in the system: -Total number of customers served on the day of the outage -Time and date when the outage began -Primary cause of outage -Address where the outage was located It is important to note that the time when the outage ended is not required in case the outage is ongoing; therefore, outages without end dates at the time of the report analysis are not included in the indices that measure duration, such as SAIDI and CAIDI. However, they are included in the calculations measuring interruption frequencies, such as SAIFI or MAIFI, as well as in the analysis of outage causes. Due to the differences in how some utilities analyze major events (MEs) relative to their base statistics, it is important to note how they are calculated and used in this report. An example of a major event could be severe weather, such as a tornado or thunderstorm, which can lead to unusually long outages in comparison to your distribution system's typical outage. In the eReliability Tracker and in this report, the APPA major event threshold is used, which is a calculation based directly on outage events, rather than event days. The major event threshold allows a utility to remove outages that exceed the IEEE 2.5 beta threshold for events. The threshold takes into account the utility's past outage history up to 10 years in order to make this calculation. In the eReliability Tracker, if a utility does not have at least 36 outage events prior to the year being analyzed, no threshold is calculated; therefore, the field below showing your utility's threshold will be blank and the calculations without MEs in the SAIDI section of this report will be the same as the calculations with MEs for your utility. More outage history will provide a better threshold for your utility. Your utility's major event threshold is (minutes). If you wish to remove major events, the threshold calculated above is important to note because it impacts your SAIDI analysis. For the next year, based on your utility's outage history, any event with a SAIDI greater than minutes is considered as a major event and can be removed in your analysis. The tables in this section can be used by utilities to better understand the performance of their electric system relative to other utilities nationally and to those within their region or size class. In the SAIDI section, indices are calculated for all outages with and without major events; furthermore, the data are broken down to show calculations for scheduled and unscheduled outages. For each of the reliability 1 If there is no major event threshold calculated for your utility,these fields are left blank and the calculations in this report including Major Events and excluding them will be the same.Your utility must have at least 36 outage events recorded in the eReliability Tracker in order to calculate a Major Event Threshold. 3 54