Table 8.12.B. U.S. Transformer Sustained Automatic Outage Counts
and Hours by High-Voltage Size and NERC Region, 2012
 

Sustained Automatic Outage Counts

High-Side Voltage (kV)
Eastern Interconnection TRE WECC Contiguous U.S.
100-199 -- -- -- --
200-299 -- -- 1.00 1.00
300-399 2.00 -- 4.00 6.00
400-599 14.00 -- 11.00 25.00
600+ -- -- -- --
Grand Total 16.00 -- 16.00 32.00

 

Sustained Automatic Outage Hours

High-Side Voltage (kV)
Eastern Interconnection TRE WECC Contiguous U.S.
100-199 -- -- -- --
200-299 -- -- 27.58 27.58
300-399 153.25 -- 15.87 169.12
400-599 3,070.88 -- 258.37 3,329.25
600+ -- -- -- --
Grand Total 3,224.13 -- 301.82 3,525.95

 

Outage Hours per Outage Incident
  Eastern Interconnection TRE WECC Contiguous U.S.
Rate 201.51 -- 18.86 110.19

Notes:
* = Value is less than half of the smallest unit of measure. (e.g., for values with no decimals, the smallest unit is 1 then values under 0.5 are shown as *.)
Eastern NERC Regions are aggregated to preserve confidentiality.
An Automatic Outage is an outage which results from the automatic operation of a switching device, causing an Element to change from an In-Service State to a not In-Service State.
A Sustained Outage is an automatic outage with an outage duration of a minute or greater.
Source: U.S. Energy Information Administration, Form EIA-411, "Coordinated Bulk Power Supply Program Report."