Table 8.13.A. U.S. Transmission Circuit Sustained Automatic Outage Counts and Hours by Cause Code and by NERC Region, 2013
 

  AC & DC Circuit Outage Counts
Sustained Outage Causes FRCC MRO NPCC RFC SERC SPP TRE WECC Contiguous U.S.
Weather, excluding lightning 3.00 60.00 24.00 17.00 14.00 25.00 4.00 50.00 197.00
Lightning 6.00 11.00 6.00 4.00 21.00 14.00 11.00 54.00 127.00
Environmental -- -- -- -- -- 2.00 -- 5.00 7.00
Contamination 4.00 4.00 -- 1.00 15.00 -- 6.00 16.00 46.00
Foreign Interference 21.00 -- 1.00 12.00 28.00 2.00 2.00 23.00 89.00
Fire 1.00 -- 1.00 1.00 3.00 -- -- 50.00 56.00
Vandalism, Terrorism, or Malicious Acts -- -- -- -- 7.00 -- -- -- 7.00
Failed AC Substation Equipment 8.00 24.00 21.00 46.00 42.00 18.00 14.00 59.00 232.00
Failed AC/DC Terminal Equipment -- 3.00 -- 4.00 -- -- -- 1.00 8.00
Failed Protection System Equipment 9.00 16.00 17.00 23.00 42.00 3.00 10.00 39.00 159.00
Failed AC Circuit Equipment 39.00 15.00 17.00 23.00 53.00 12.00 11.00 63.00 233.00
Failed DC Circuit Equipment -- 2.00 -- -- -- -- -- -- 2.00
Vegetation 1.00 -- 3.00 2.00 14.00 1.00 -- 4.00 25.00
Power System Condition 1.00 1.00 3.00 11.00 3.00 14.00 3.00 60.00 96.00
Human Error 8.00 22.00 15.00 39.00 36.00 12.00 6.00 86.00 224.00
Unknown 15.00 27.00 7.00 15.00 26.00 7.00 9.00 156.00 262.00
Other 1.00 10.00 7.00 6.00 11.00 6.00 4.00 73.00 118.00
TOTAL 117.00 195.00 122.00 214.00 315.00 116.00 80.00 739.00 1,898.00

 

  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 2.56% 30.77% 19.67% 7.94% 4.44% 21.55% 5.00% 6.77% 10.38%
Lightning 5.13% 5.64% 4.92% 1.87% 6.67% 12.07% 13.75% 7.31% 6.69%
Environmental -- -- -- -- -- 1.72% -- 0.68% 0.37%
Contamination 3.42% 2.05% -- 0.47% 4.76% -- 7.50% 2.17% 2.42%
Foreign Interference 17.95% -- 0.82% 5.61% 8.89% 1.72% 2.50% 3.11% 4.69%
Fire 0.85% -- 0.82% 0.47% 0.95% -- -- 6.77% 2.95%
Vandalism, Terrorism, or Malicious Acts -- -- -- -- 2.22% -- -- -- 0.37%
Failed AC Substation Equipment 6.84% 12.31% 17.21% 21.50% 13.33% 15.52% 17.50% 7.98% 12.22%
Failed AC/DC Terminal Equipment -- 1.54% -- 1.87% -- -- -- 0.14% 0.42%
Failed Protection System Equipment 7.69% 8.21% 13.93% 10.75% 13.33% 2.59% 12.50% 5.28% 8.38%
Failed AC Circuit Equipment 33.33% 7.69% 13.93% 10.75% 16.83% 10.34% 13.75% 8.53% 12.28%
Failed DC Circuit Equipment -- 1.03% -- -- -- -- -- -- 0.11%
Vegetation 0.85% -- 2.46% 0.93% 4.44% 0.86% -- 0.54% 1.32%
Power System Condition 0.85% 0.51% 2.46% 5.14% 0.95% 12.07% 3.75% 8.12% 5.06%
Human Error 6.84% 11.28% 12.30% 18.22% 11.43% 10.34% 7.50% 11.64% 11.80%
Unknown 12.82% 13.85% 5.74% 7.01% 8.25% 6.03% 11.25% 21.11% 13.80%
Other 0.85% 5.13% 5.74% 2.80% 3.49% 5.17% 5.00% 9.88% 6.22%
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 10.60 483.02 278.93 7,598.68 686.40 1,652.42 50.57 164.08 10,924.70
Lightning 8.30 3.35 3.50 42.37 84.05 12.40 50.88 100.93 305.78
Environmental -- -- -- 2,064.52 -- 1.90 -- 27.32 2,093.74
Contamination 5.65 0.25 -- 0.15 422.17 -- 19.03 113.32 560.57
Foreign Interference 76.95 -- 10.67 27.38 220.37 0.03 237.23 152.08 724.71
Fire 0.02 -- 64.63 2.10 68.63 -- -- 782.40 917.78
Vandalism, Terrorism, or Malicious Acts -- -- -- -- 637.18 -- -- -- 637.18
Failed AC Substation Equipment 255.20 2,103.23 13,974.55 9,162.87 657.68 84.82 233.50 1,734.23 28,206.08
Failed AC/DC Terminal Equipment -- 32.90 -- 22.88 -- -- -- 3.32 59.10
Failed Protection System Equipment 4.98 42.47 80.60 117.40 457.35 115.17 129.18 87.57 1,034.72
Failed AC Circuit Equipment 366.88 1,507.10 3,676.37 1,579.03 1,257.02 411.35 1,144.62 1,436.03 11,378.40
Failed DC Circuit Equipment -- 69.38 -- -- -- -- -- -- 69.38
Vegetation 22.28 -- 68.52 50.77 124.33 16.73 -- 47.62 330.25
Power System Condition 12.50 0.17 26.83 60.85 13.43 125.43 0.25 590.70 830.16
Human Error 13.05 24.43 25.75 193.44 98.62 8.22 21.62 444.83 829.96
Unknown 20.53 34.88 1,346.88 73.97 147.90 34.53 36.58 286.19 1,981.46
Other 5.70 13.55 26.70 111.16 62.30 13.98 13.05 202.63 449.07
TOTAL 802.64 4,314.73 19,583.93 21,107.57 4,937.43 2,476.98 1,936.51 6,173.25 61,333.04

 

  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 1.32% 11.19% 1.42% 36.00% 13.90% 66.71% 2.61% 2.66% 17.81%
Lightning 1.03% 0.08% 0.02% 0.20% 1.70% 0.50% 2.63% 1.63% 0.50%
Environmental -- -- -- 9.78% -- 0.08% -- 0.44% 3.41%
Contamination 0.70% 0.01% -- 0.00% 8.55% -- 0.98% 1.84% 0.91%
Foreign Interference 9.59% -- 0.05% 0.13% 4.46% 0.00% 12.25% 2.46% 1.18%
Fire 0.00% -- 0.33% 0.01% 1.39% -- -- 12.67% 1.50%
Vandalism, Terrorism, or Malicious Acts -- -- -- -- 12.91% -- -- -- 1.04%
Failed AC Substation Equipment 31.80% 48.75% 71.36% 43.41% 13.32% 3.42% 12.06% 28.09% 45.99%
Failed AC/DC Terminal Equipment -- 0.76% -- 0.11% -- -- -- 0.05% 0.10%
Failed Protection System Equipment 0.62% 0.98% 0.41% 0.56% 9.26% 4.65% 6.67% 1.42% 1.69%
Failed AC Circuit Equipment 45.71% 34.93% 18.77% 7.48% 25.46% 16.61% 59.11% 23.26% 18.55%
Failed DC Circuit Equipment -- 1.61% -- -- -- -- -- -- 0.11%
Vegetation 2.78% -- 0.35% 0.24% 2.52% 0.68% -- 0.77% 0.54%
Power System Condition 1.56% 0.00% 0.14% 0.29% 0.27% 5.06% 0.01% 9.57% 1.35%
Human Error 1.63% 0.57% 0.13% 0.92% 2.00% 0.33% 1.12% 7.21% 1.35%
Unknown 2.56% 0.81% 6.88% 0.35% 3.00% 1.39% 1.89% 4.64% 3.23%
Other 0.71% 0.31% 0.14% 0.53% 1.26% 0.56% 0.67% 3.28% 0.73%
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."