NTPC tracks customer outages originating on our generation, transmission, and distribution equipment in all locations. Outage statistics are reported regularly to our Board of Directors, and externally to the Canadian Electricity Association and the Northwest Territories Public Utilities Board.
Customer outage statistics are tracked and reported using standard definitions developed by the Canadian Electricity Association Service Continuity Committee. NTPC has participated in national collection and reporting using these definitions since 2011. This methodology was adopted by the Northwest Territories Public Utilities Board (PUB) on NTPC's recommendation in 2012. The three key indicators in outage reporting are known by the acronyms SAIDI, SAIFI, and CAIDI.
SAIDI is the “System Average Interruption Duration Index”. It tells us how many hours an average customer is without power during the year.
SAIFI is an acronym for “System Average Interruption Frequency Index”. It represents the total number of interruptions (outages of any duration) experienced by an average customer during the year.
CAIDI, the “Customer Average Interruption Duration Index” is the average length of time (in hours) to restore power when an outage occurs.