| Table 8.13.A. U.S. Transmission Circuit Sustained Automatic Outage Counts and Hours by Cause Code and by NERC Region, 2011 |
| AC & DC Circuit Outage Counts | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Sustained Outage Causes | FRCC | MRO | NPCC | RFC | SERC | SPP | TRE | WECC | Contiguous U.S. |
| Weather, excluding lightning | 9.00 | 42.00 | 7.00 | 27.00 | 135.00 | 23.00 | 10.00 | 76.00 | 329.00 |
| Lightning | 9.00 | 17.00 | 7.00 | 23.00 | 39.00 | 19.00 | 18.00 | 87.00 | 219.00 |
| Environmental | -- | -- | -- | 3.00 | -- | 1.00 | -- | 1.00 | 5.00 |
| Contamination | 1.00 | -- | -- | 2.00 | 29.00 | 1.00 | 17.00 | 4.00 | 54.00 |
| Foreign Interference | 27.00 | 2.00 | 4.00 | 9.00 | 19.00 | 2.00 | 1.00 | 31.00 | 95.00 |
| Fire | 4.00 | -- | -- | 2.00 | 6.00 | 4.00 | 14.00 | 18.00 | 48.00 |
| Vandalism, Terrorism, or Malicious Acts | -- | -- | -- | -- | 1.00 | -- | -- | 2.00 | 3.00 |
| Failed AC Substation Equipment | 5.00 | 13.00 | 8.00 | 67.00 | 53.00 | 14.00 | 26.00 | 75.00 | 261.00 |
| Failed AC/DC Terminal Equipment | -- | 12.00 | -- | 4.00 | -- | -- | -- | 5.00 | 21.00 |
| Failed Protection System Equipment | 9.00 | 22.00 | 13.00 | 45.00 | 34.00 | 3.00 | 8.00 | 42.00 | 176.00 |
| Failed AC Circuit Equipment | 28.00 | 4.00 | 22.00 | 35.00 | 54.00 | 22.00 | 11.00 | 58.00 | 234.00 |
| Failed DC Circuit Equipment | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Vegetation | -- | -- | 6.00 | 4.00 | 13.00 | 1.00 | -- | 7.00 | 31.00 |
| Power System Condition | 1.00 | 3.00 | -- | 8.00 | 13.00 | 1.00 | -- | 77.00 | 103.00 |
| Human Error | 9.00 | 27.00 | 8.00 | 36.00 | 29.00 | 8.00 | 19.00 | 92.00 | 228.00 |
| Unknown | 17.00 | 15.00 | 11.00 | 17.00 | 21.00 | 17.00 | 5.00 | 222.00 | 325.00 |
| Other | 2.00 | 4.00 | 1.00 | 10.00 | 16.00 | 3.00 | 3.00 | 53.00 | 92.00 |
| TOTAL | 121.00 | 161.00 | 87.00 | 292.00 | 462.00 | 119.00 | 132.00 | 850.00 | 2,224.00 |
| 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 | 7.44% | 26.09% | 8.05% | 9.25% | 29.22% | 19.33% | 7.58% | 8.94% | 14.79% |
| Lightning | 7.44% | 10.56% | 8.05% | 7.88% | 8.44% | 15.97% | 13.64% | 10.24% | 9.85% |
| Environmental | 0.00% | 0.00% | 0.00% | 1.03% | 0.00% | 0.84% | 0.00% | 0.12% | 0.22% |
| Contamination | 0.83% | 0.00% | 0.00% | 0.68% | 6.28% | 0.84% | 12.88% | 0.47% | 2.43% |
| Foreign Interference | 22.31% | 1.24% | 4.60% | 3.08% | 4.11% | 1.68% | 0.76% | 3.65% | 4.27% |
| Fire | 3.31% | 0.00% | 0.00% | 0.68% | 1.30% | 3.36% | 10.61% | 2.12% | 2.16% |
| Vandalism, Terrorism, or Malicious Acts | 0.00% | 0.00% | 0.00% | 0.00% | 0.22% | 0.00% | 0.00% | 0.24% | 0.13% |
| Failed AC Substation Equipment | 4.13% | 8.07% | 9.20% | 22.95% | 11.47% | 11.76% | 19.70% | 8.82% | 11.74% |
| Failed AC/DC Terminal Equipment | 0.00% | 7.45% | 0.00% | 1.37% | 0.00% | 0.00% | 0.00% | 0.59% | 0.94% |
| Failed Protection System Equipment | 7.44% | 13.66% | 14.94% | 15.41% | 7.36% | 2.52% | 6.06% | 4.94% | 7.91% |
| Failed AC Circuit Equipment | 23.14% | 2.48% | 25.29% | 11.99% | 11.69% | 18.49% | 8.33% | 6.82% | 10.52% |
| Failed DC Circuit Equipment | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% |
| Vegetation | 0.00% | 0.00% | 6.90% | 1.37% | 2.81% | 0.84% | 0.00% | 0.82% | 1.39% |
| Power System Condition | 0.83% | 1.86% | 0.00% | 2.74% | 2.81% | 0.84% | 0.00% | 9.06% | 4.63% |
| Human Error | 7.44% | 16.77% | 9.20% | 12.33% | 6.28% | 6.72% | 14.39% | 10.82% | 10.25% |
| Unknown | 14.05% | 9.32% | 12.64% | 5.82% | 4.55% | 14.29% | 3.79% | 26.12% | 14.61% |
| Other | 1.65% | 2.48% | 1.15% | 3.42% | 3.46% | 2.52% | 2.27% | 6.24% | 4.14% |
| 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 | 4.00 | 837.48 | 314.47 | 3,022.58 | 16,920.95 | 192.82 | 3.08 | 220.87 | 21,516.25 |
| Lightning | 68.55 | 5.33 | 6.53 | 70.12 | 60.72 | 44.50 | 28.72 | 196.87 | 481.34 |
| Environmental | -- | -- | -- | 2,073.68 | -- | -- | -- | 24.00 | 2,097.68 |
| Contamination | 4.97 | -- | -- | 3.43 | 481.23 | 0.03 | 59.45 | 31.42 | 580.53 |
| Foreign Interference | 43.65 | 0.65 | 6.48 | 72.08 | 390.70 | 0.12 | 2.00 | 5.57 | 521.25 |
| Fire | 0.37 | -- | -- | 22.78 | 181.20 | 93.97 | 691.22 | 114.98 | 1,104.52 |
| Vandalism, Terrorism, or Malicious Acts | -- | -- | -- | -- | 0.03 | -- | -- | 41.85 | 41.88 |
| Failed AC Substation Equipment | 1,186.19 | 1,870.40 | 961.60 | 11,018.19 | 7,982.22 | 251.43 | 225.97 | 1,967.20 | 25,463.20 |
| Failed AC/DC Terminal Equipment | -- | 100.52 | -- | 356.42 | -- | -- | -- | 296.93 | 753.87 |
| Failed Protection System Equipment | 20.62 | 233.77 | 189.73 | 544.25 | 237.45 | 3.50 | 25.68 | 346.12 | 1,601.12 |
| Failed AC Circuit Equipment | 323.43 | 7,276.47 | 7,545.57 | 5,945.62 | 2,400.18 | 425.35 | 445.60 | 2,614.23 | 26,976.45 |
| Failed DC Circuit Equipment | -- | 214.15 | -- | -- | -- | -- | -- | -- | 214.15 |
| Vegetation | -- | -- | 58.13 | 25.20 | 580.68 | 10.07 | -- | 179.10 | 853.18 |
| Power System Condition | 0.18 | 7.52 | 0.08 | 223.98 | 91.73 | 0.02 | 234.22 | 313.36 | 871.09 |
| Human Error | 1.52 | 19.94 | 1,477.53 | 44.40 | 143.10 | 9.15 | 155.75 | 128.54 | 1,979.93 |
| Unknown | 19.65 | 54.46 | 18.47 | 25.32 | 59.50 | 48.92 | 1.70 | 2,459.60 | 2,687.62 |
| Other | 1.75 | 163.01 | -- | 3,815.92 | 13.25 | 25.88 | 35.28 | 234.59 | 4,289.68 |
| TOTAL | 1,674.88 | 10,783.70 | 10,578.59 | 27,263.97 | 29,542.94 | 1,105.76 | 1,908.67 | 9,175.23 | 92,033.74 |
| 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 | 0.24% | 7.77% | 2.97% | 11.09% | 57.28% | 17.44% | 0.16% | 2.41% | 23.38% |
| Lightning | 4.09% | 0.05% | 0.06% | 0.26% | 0.21% | 4.02% | 1.50% | 2.15% | 0.52% |
| Environmental | 0.00% | 0.00% | 0.00% | 7.61% | 0.00% | 0.00% | 0.00% | 0.26% | 2.28% |
| Contamination | 0.30% | 0.00% | 0.00% | 0.01% | 1.63% | 0.00% | 3.11% | 0.34% | 0.63% |
| Foreign Interference | 2.61% | 0.01% | 0.06% | 0.26% | 1.32% | 0.01% | 0.10% | 0.06% | 0.57% |
| Fire | 0.02% | 0.00% | 0.00% | 0.08% | 0.61% | 8.50% | 36.21% | 1.25% | 1.20% |
| Vandalism, Terrorism, or Malicious Acts | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% | 0.46% | 0.05% |
| Failed AC Substation Equipment | 70.82% | 17.34% | 9.09% | 40.41% | 27.02% | 22.74% | 11.84% | 21.44% | 27.67% |
| Failed AC/DC Terminal Equipment | 0.00% | 0.93% | 0.00% | 1.31% | 0.00% | 0.00% | 0.00% | 3.24% | 0.82% |
| Failed Protection System Equipment | 1.23% | 2.17% | 1.79% | 2.00% | 0.80% | 0.32% | 1.35% | 3.77% | 1.74% |
| Failed AC Circuit Equipment | 19.31% | 67.48% | 71.33% | 21.81% | 8.12% | 38.47% | 23.35% | 28.49% | 29.31% |
| Failed DC Circuit Equipment | 0.00% | 1.99% | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% | 0.23% |
| Vegetation | 0.00% | 0.00% | 0.55% | 0.09% | 1.97% | 0.91% | 0.00% | 1.95% | 0.93% |
| Power System Condition | 0.01% | 0.07% | 0.00% | 0.82% | 0.31% | 0.00% | 12.27% | 3.42% | 0.95% |
| Human Error | 0.09% | 0.18% | 13.97% | 0.16% | 0.48% | 0.83% | 8.16% | 1.40% | 2.15% |
| Unknown | 1.17% | 0.51% | 0.17% | 0.09% | 0.20% | 4.42% | 0.09% | 26.81% | 2.92% |
| Other | 0.10% | 1.51% | 0.00% | 14.00% | 0.04% | 2.34% | 1.85% | 2.56% | 4.66% |
| 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." |