Table 8.13.A. U.S. Transmission Circuit Sustained Automatic Outage Counts and Hours by Cause Code and by NERC Region, 2012
 

  AC & DC Circuit Outage Counts
Sustained Outage Causes FRCC MRO NPCC RFC SERC SPP TRE WECC Contiguous U.S.
Weather, excluding lightning 6.00 27.00 3.00 30.00 63.00 12.00 -- 69.00 210.00
Lightning 5.00 10.00 8.00 5.00 31.00 16.00 13.00 57.00 145.00
Environmental -- 1.00 1.00 5.00 -- 1.00 -- -- 8.00
Contamination 14.00 -- -- -- 22.00 3.00 6.00 7.00 52.00
Foreign Interference 34.00 3.00 -- 4.00 13.00 1.00 2.00 14.00 71.00
Fire -- 2.00 -- 1.00 6.00 3.00 1.00 85.00 98.00
Vandalism, Terrorism, or Malicious Acts -- -- -- -- 2.00 -- -- 1.00 3.00
Failed AC Substation Equipment 18.00 16.00 35.00 63.00 57.00 16.00 15.00 65.00 285.00
Failed AC/DC Terminal Equipment -- 14.00 -- 4.00 -- -- -- 6.00 24.00
Failed Protection System Equipment 16.00 10.00 25.00 42.00 35.00 7.00 11.00 53.00 199.00
Failed AC Circuit Equipment 26.00 12.00 25.00 34.00 47.00 14.00 6.00 79.00 243.00
Failed DC Circuit Equipment -- 1.00 -- -- -- -- -- 3.00 4.00
Vegetation 2.00 -- 3.00 7.00 17.00 -- -- 10.00 39.00
Power System Condition 1.00 7.00 -- 17.00 2.00 3.00 5.00 42.00 77.00
Human Error 8.00 36.00 10.00 38.00 43.00 6.00 18.00 104.00 263.00
Unknown 14.00 14.00 6.00 8.00 22.00 13.00 1.00 124.00 202.00
Other 7.00 10.00 11.00 14.00 14.00 10.00 2.00 77.00 145.00
TOTAL 151.00 163.00 127.00 272.00 374.00 105.00 80.00 796.00 2,068.00

 

  Percentage of Total AC & DC Circuit Outage Counts
Sustained Outage Causes FRCC MRO NPCC RFC SERC SPP TRE WECC Contiguous U.S.
Weather, excluding lightning 3.97% 16.56% 2.36% 11.03% 16.84% 11.43% 0.00% 8.67% 10.15%
Lightning 3.31% 6.13% 6.30% 1.84% 8.29% 15.24% 16.25% 7.16% 7.01%
Environmental 0.00% 0.61% 0.79% 1.84% 0.00% 0.95% 0.00% 0.00% 0.39%
Contamination 9.27% 0.00% 0.00% 0.00% 5.88% 2.86% 7.50% 0.88% 2.51%
Foreign Interference 22.52% 1.84% 0.00% 1.47% 3.48% 0.95% 2.50% 1.76% 3.43%
Fire 0.00% 1.23% 0.00% 0.37% 1.60% 2.86% 1.25% 10.68% 4.74%
Vandalism, Terrorism, or Malicious Acts 0.00% 0.00% 0.00% 0.00% 0.53% 0.00% 0.00% 0.13% 0.15%
Failed AC Substation Equipment 11.92% 9.82% 27.56% 23.16% 15.24% 15.24% 18.75% 8.17% 13.78%
Failed AC/DC Terminal Equipment 0.00% 8.59% 0.00% 1.47% 0.00% 0.00% 0.00% 0.75% 1.16%
Failed Protection System Equipment 10.60% 6.13% 19.69% 15.44% 9.36% 6.67% 13.75% 6.66% 9.62%
Failed AC Circuit Equipment 17.22% 7.36% 19.69% 12.50% 12.57% 13.33% 7.50% 9.92% 11.75%
Failed DC Circuit Equipment 0.00% 0.61% 0.00% 0.00% 0.00% 0.00% 0.00% 0.38% 0.19%
Vegetation 1.32% 0.00% 2.36% 2.57% 4.55% 0.00% 0.00% 1.26% 1.89%
Power System Condition 0.66% 4.29% 0.00% 6.25% 0.53% 2.86% 6.25% 5.28% 3.72%
Human Error 5.30% 22.09% 7.87% 13.97% 11.50% 5.71% 22.50% 13.07% 12.72%
Unknown 9.27% 8.59% 4.72% 2.94% 5.88% 12.38% 1.25% 15.58% 9.77%
Other 4.64% 6.13% 8.66% 5.15% 3.74% 9.52% 2.50% 9.67% 7.01%
TOTAL 100.00% 100.00% 100.00% 100.00% 100.00% 100.00% 100.00% 100.00% 100.00%

 

  AC & DC Circuit Outage Hours
Sustained Outage Causes FRCC MRO NPCC RFC SERC SPP TRE WECC Contiguous U.S.
Weather, excluding lightning 23.98 192.92 181.36 7,737.12 2,294.12 322.17 -- 615.95 11,367.62
Lightning 26.52 2.78 17.45 8.15 56.57 88.63 41.72 73.43 315.25
Environmental -- 7.80 92.67 2,954.45 -- 0.67 -- -- 3,055.59
Contamination 127.78 -- -- -- 396.05 3.55 0.17 12.62 540.17
Foreign Interference 97.98 13.02 -- 21.83 138.82 0.13 1.32 88.40 361.50
Fire -- 1.38 -- 10.45 30.75 29.27 18.83 1,986.53 2,077.21
Vandalism, Terrorism, or Malicious Acts -- -- -- -- 27.62 -- -- 0.10 27.72
Failed AC Substation Equipment 2,071.87 273.65 10,312.33 4,773.00 600.90 248.70 316.97 641.65 19,239.07
Failed AC/DC Terminal Equipment -- 118.87 -- 18.30 -- -- -- 21.95 159.12
Failed Protection System Equipment 125.15 77.08 745.90 234.96 183.53 14.78 19.87 469.53 1,870.80
Failed AC Circuit Equipment 304.38 276.53 2,504.21 3,597.40 2,662.10 337.25 110.47 10,406.28 20,198.62
Failed DC Circuit Equipment -- 78.15 -- -- -- -- -- 28.98 107.13
Vegetation 23.45 -- 53.30 180.28 171.58 -- -- 86.90 515.51
Power System Condition 0.07 97.35 -- 84.75 12.17 24.32 145.57 4,890.80 5,255.03
Human Error 17.27 32.05 21.40 179.02 156.77 6.92 26.98 4,260.85 4,701.26
Unknown 26.98 11.47 62.78 9.70 132.02 68.95 0.37 486.40 798.67
Other 6.85 129.92 253.47 47.82 260.70 364.17 0.33 168.27 1,231.53
TOTAL 2,852.28 1,312.97 14,244.87 19,857.23 7,123.70 1,509.51 682.60 24,238.64 71,821.80

 

  Percentage of Total AC & DC Circuit Outage Hours
Sustained Outage Causes FRCC MRO NPCC RFC SERC SPP TRE WECC Contiguous U.S.
Weather, excluding lightning 0.84% 14.69% 1.27% 38.96% 32.20% 21.34% 0.00% 2.54% 15.83%
Lightning 0.93% 0.21% 0.12% 0.04% 0.79% 5.87% 6.11% 0.30% 0.44%
Environmental 0.00% 0.59% 0.65% 14.88% 0.00% 0.04% 0.00% 0.00% 4.25%
Contamination 4.48% 0.00% 0.00% 0.00% 5.56% 0.24% 0.02% 0.05% 0.75%
Foreign Interference 3.44% 0.99% 0.00% 0.11% 1.95% 0.01% 0.19% 0.36% 0.50%
Fire 0.00% 0.11% 0.00% 0.05% 0.43% 1.94% 2.76% 8.20% 2.89%
Vandalism, Terrorism, or Malicious Acts 0.00% 0.00% 0.00% 0.00% 0.39% 0.00% 0.00% 0.00% 0.04%
Failed AC Substation Equipment 72.64% 20.84% 72.39% 24.04% 8.44% 16.48% 46.44% 2.65% 26.79%
Failed AC/DC Terminal Equipment 0.00% 9.05% 0.00% 0.09% 0.00% 0.00% 0.00% 0.09% 0.22%
Failed Protection System Equipment 4.39% 5.87% 5.24% 1.18% 2.58% 0.98% 2.91% 1.94% 2.60%
Failed AC Circuit Equipment 10.67% 21.06% 17.58% 18.12% 37.37% 22.34% 16.18% 42.93% 28.12%
Failed DC Circuit Equipment 0.00% 5.95% 0.00% 0.00% 0.00% 0.00% 0.00% 0.12% 0.15%
Vegetation 0.82% 0.00% 0.37% 0.91% 2.41% 0.00% 0.00% 0.36% 0.72%
Power System Condition 0.00% 7.41% 0.00% 0.43% 0.17% 1.61% 21.33% 20.18% 7.32%
Human Error 0.61% 2.44% 0.15% 0.90% 2.20% 0.46% 3.95% 17.58% 6.55%
Unknown 0.95% 0.87% 0.44% 0.05% 1.85% 4.57% 0.05% 2.01% 1.11%
Other 0.24% 9.90% 1.78% 0.24% 3.66% 24.13% 0.05% 0.69% 1.71%
TOTAL 100.00% 100.00% 100.00% 100.00% 100.00% 100.00% 100.00% 100.00% 100.00%

Notes:
Detailed information on the Transmission Availability Data System outage causes is available at:
http://www.nerc.com/docs/pc/tadswg/Appendix%207%2020101202a%20clean.pdf
Source: U.S. Energy Information Administration, Form EIA-411, "Coordinated Bulk Power Supply Program Report."