Table 8.12.B. U.S. Transformer Sustained Automatic Outage Counts
and Hours by High-Voltage Size and NERC Region, 2013
 

Sustained Automatic Outage Counts

High-Side Voltage (kV)
Eastern Interconnection TRE WECC Contiguous U.S.
100-199 -- -- -- --
200-299 3.00 -- 7.00 10.00
300-399 17.00 -- 10.00 27.00
400-599 30.00 -- 16.00 46.00
600+ 9.00 -- -- 9.00
Grand Total 59.00 -- 33.00 92.00

 

Sustained Automatic Outage Hours

High-Side Voltage (kV)
Eastern Interconnection TRE WECC Contiguous U.S.
100-199 -- -- -- --
200-299 32.25 -- 44.90 77.15
300-399 303.36 -- 261.15 564.51
400-599 11,948.26 -- 1,015.47 12,963.73
600+ 6,986.98 -- -- 6,986.98
Grand Total 19,270.85 -- 1,321.52 20,592.37

 

Outage Hours per Outage Incident
  Eastern Interconnection TRE WECC Contiguous U.S.
Rate 326.62 -- 40.05 223.83

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."