About This Metric
This metric uses data and calculations directly from the NERC TADS effort and shows the overall percent of time that AC circuits and transformers are available and in service. This value is calculated for each element type using sustained automatic and non-automatic outages for AC circuits and for transformers operated at 200 kV and above for each Regional Entity, Interconnection, and consolidated values for NERC. Note that TRE has no transformers with low-side voltages at 200 kV and above. The 2010 and 2011 element availability percentage (APC) for AC circuits and for transformers operated at 200 kV and above are shown. The values are all over 90 percent. Continued metric data collection for this metric is required for at least a few more years in order to assess the value of this metric. The non-automatic outage data needed to calculate this metric was first collected for the calendar year 2010 as part of the TADS process.
Metric Definition Document
