A Lifeline for Power Lines

Managing the Three Ts of Electric Transmission with GIS
Where were you on August 14, 2003, at 4:00 p.m. (Eastern time)? That’s when much of the northeastern United States was blacked out. No power. Sweaty office workers stuck in elevators from Manhattan to Cleveland. Traffic signals dead everywhere. Tons of food spoiled. At the time, people were still wary from the September 11 attacks.
The culprit for disaster this time? Well, there were many. But two of them were rather skinny Ailanthus trees that had become a little too big for their britches.
The trees grew too close to the heavily loaded Stuart-Atlanta 345 kV transmission line, a major power corridor between the United States and Canada. When transmission lines carry a lot of power, their conductors sag. As fate would have it, at the worst possible time, the sagging lines came in contact with those two little trees. So the line tripped out. This was one in a series of cascading events—which created one of the largest power failures in the nation’s history.
The 2003 blackout illustrates the devastating impact a transmission failure can have on communities. It’s true that most power failures aren’t devastating. That’s because many happen on the lower-voltage distribution lines that you see on city streets. People crash into poles, or ice forms on the lines, and the power fails. While these situations cause havoc, they are often localized. When a transmission line fails or is damaged, all hell breaks loose. Talk to Alabama Power, for instance. That team lost a big chunk of their transmission system during a devastating tornado a couple of years ago.
Too bad we didn’t have the ArcGIS platform during the 2003 blackout.
GIS to the Rescue
People often say that the blackout of 2003 was due to the three Ts—trees, technology, and training. Trees grow too big. Technology fails. And lack of training prevented people from making correct and timely decisions.
Today, many transmission utilities have embraced ArcGIS technology to help with the three Ts. GIS has become a critical technology for improving tree and vegetation management. But the software comes into play in other areas, too. Operators, for instance, improve situational awareness. Back in 2003, control room operators had no easy way to spatially visualize the geographic context of the transmission system. They had only schematic diagrams. With ArcGIS, operators can now see the transmission system in a more meaningful, contextualized way.
With the ArcGIS platform, transmission operators can not only figure out what’s going on from an electrical perspective but also see what’s happening near the lines. They can see historic rainfall data, identify places that are close to hazards, and understand earthquake or lightning densities. And, very importantly, staff can figure out where those pesky trees may encroach on the lines. In effect, the people who run the transmission system have access to much more than what’s visible on their schematics. Even better, they have superior access to information from the field or from contractors doing work on or near the lines. Transmission operators can share, collaborate, and communicate throughout the organization with the platform.
Running in Real Time
In the old days, it was tough getting information from one system to another. In the transmission world, folks use the real-time supervisory control and data acquisition (SCADA) system. SCADA captures millions of measurements from all kinds of sensors. Whenever something goes haywire along the transmission line, SCADA knows about it within milliseconds.
Today, Esri and OSIsoft have joined forces to make it a snap to get all this real-time data (both current and historic) from SCADA into the ArcGIS platform. The union of these two technologies makes data available to anyone who has access to the ArcGIS platform. Also, in the old days, employees had to be highly trained on the use of real-time data, but that’s all changed. With out-of-the-box software, utilities can take full advantage of the huge volumes of real-time data and combine it with geospatial data to see patterns as they unfold.
So managing the three Ts—trees, technology, and training—is a lot easier with the ArcGIS platform.


Learn more about GIS for transmission at

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