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The Squirrel in the Substation
30.04.2021
When I talk to people about transportation, the conversation usually turns to trains, planes, ships, trucks, and cars: the hardware behind the movement of things. The methods and processes supporting the hardware rarely come up in conversation, which is a shame. To my mind, the methods and processes of operating a transportation network are of equal interest, if not as intriguing to watch.
As an example, let’s look at a transportation network that does not use any vehicles at all. This transportation system moves a product that can move on its own, given the necessary infrastructure. The product is weightless, has no discernible mass or volume, is usually undetectable by human senses, and yet is readily quantifiable and potentially lethal.
This product’s transportation network shares some qualities with the finished vehicle transportation network that we work with. Both networks start with large quantities of product from supplying origins, sufficient to supply large numbers of customers every day. Both networks move their product over considerable distances and distribute their product over large areas. Both networks require specialized equipment to move their product. And, both networks can, and do, deliver large quantities of product to large users and small quantities of product to single users.
The transportation network I’m referring to is the electric power grid. The grid started as a collection of small networks bringing electricity to businesses and well-to-do homes in small sections of large cities in the 1880’s. Across the globe, the power grid has evolved into networks of region-spanning high-, medium-, and low-tension power lines that cross all types of borders and quite literally power our lives.
The electric power grid is both amazing reliable and surprisingly vulnerable. During this past winter in Southeast Michigan, the region experienced weather-related power outages affecting thousands of customers for extended periods of time. We have also seen the effects of a Category 4 hurricane on the exposed infrastructure of a power grid as Puerto Rico continues to struggle with electricity supply almost a year after the storm.
The finished vehicle network is also an outdoor activity with similar challenges. We’ve seen the impact of weather events on the transportation infrastructure required for the movement of finished vehicle shipments. Hurricanes, heavy snowfalls, ice storms, and flooding have all brought both road and rail traffic to a standstill across wide areas. A severe hailstorm can damage hundreds or even thousands of vehicles at a loading location or destination ramp.
In addition to these big issues, the American Public Power Association website states that, “Squirrels are among the top causes of power outages in the Unites States.” Electrical substations offer warm, secure spaces that are attractive for nesting during the spring breeding season, as well as for refuge from the weather during autumn and winter. Engineers and equipment designers have struggled to strike a balance between providing sufficient ventilation needed by the equipment and keeping animals out.
Along with the basic drive to seek shelter, safety, and warmth, squirrels have teeth that grow continuously. So, squirrels need to gnaw on things to keep their teeth sized and sharpened. Squirrels find electrical cable insulation excellent for this purpose, making an electrical substation a good place to call home. The website states, perhaps tongue in cheek, that electric power companies consider squirrels a more pernicious enemy than cyberattacks.
The finished vehicle network doesn’t have quite the same issue. The closest I’ve seen are photos of the “guard rattlesnakes” protecting the trucks parked around Saltillo Assembly. We have our own versions of minor issues causing major problems. An inept job of spotting empty railcars is a good example. If the railcars are just a couple of inches too close together, the end doors on the railcars cannot be opened. If the railcars are just a couple of inches too far apart, the bridge plates will not reach to bridge the gap to the next railcar in line, effectively preventing that next railcar and all the railcars behind it from being loaded.
For a network to function efficiently and effectively, all of its component parts need to function efficiently and effectively. One defective relay caused the Northeast Blackout of 1965, which plunged almost all of Ontario and the Northeastern United States into darkness for more than 12 hours. Subsequent major blackouts in the region in 1977 and 2003 followed the same basic pattern: a small failure cascaded into bigger and more widespread failures until finally the entire network failed. The failures were not necessarily just failures of equipment, either. In the case of both the 1977 blackout and the 2003 blackout, human actions compounded or accelerated the effects of the equipment failures.
A local news story from suburban Detroit recently highlighted a common thread with network issues: homeowners in a subdivision have been experiencing regular blackouts. One homeowner told the television crew that there was one pole-mounted transformer that was seen to fail. The power company came out and replaced the transformer, and the replacement subsequently failed. After several more replacements and failures of the transformer in the same location, the frustrated residents called the television station to get action. I’m curious to see if anything comes of that approach. Does treating symptoms solve systemic problems? How do we deal with both the big problems and the squirrels in the substations?
Thanks for reading. To be continued!
by Bert Ruden