Think of the time and money your utility has spent installing these devices and how much your customers depend on them...
And now some of them look like this...
The problem with this problem is that there are so many possibilities. So we'll try to take a systematic approach to find the most likely culprit. Since outages on these devices are almost always fatal, look for bits of fur, bones, or feathers. You may not have any luck since the carcasses are often removed by predators before the crew arrives. So, we'll take the next step. How's your right-of-way clearing and maintenance program going? Are trees and shrubbery becoming a permanent part of your distribution facilities inventory? If so, the following equations are probably true:
A generalization...if there are overgrown trees or large shrubs in your service territory next to your distribution poles and conductors, and if you are having unexplained outages (transformers, OCRs, voltage regulators, capacitors), you have a problem with squirrels. Assuming this is the case, what can you do?
- Trees + Poles = Squirrels on Overhead Devices
- Squirrels + Overhead Devices = Disaster
What if you're fairly sure the problem isn't squirrels? The next choice would be our feathered friends. If you think there is the slightest chance you are dealing with a raptor (eagles, hawks, owls, vultures, ospreys), go here. Bird-caused outages on distribution systems (except for you folks out West) are not nearly as common as those caused by squirrels. Could birds have more sense than squirrels? Actually, overhead distribution devices are usually too exposed to be attractive as nesting or roosting sites, but they make great pit stops. Unfortunately, the placement of the bushings and stingers make it possible for even a fairly small bird to cause a wingtip contact, phase to phase or phase to ground.
- The first, best cure is clearing and maintaining your right-of-way. (FYI - squirrels seldom climb poles, they almost always gain access to utility equipment from nearby trees or buildings). Pay particular attention to those areas where the unexplained outages are occurring.
- If this isn't possible, you'll have to find a way to either prevent access to your equipment or somehow prevent an animal contact with the energized devices.
- If you haven't read the section on squirrels, click on the link and read it now.
- So the answer, in most cases, seems to be protecting the equipment. This means bushing covers, stinger covers, electrostatic guards, shields, and so forth.
- See the recommendations at the end of this section.
There are some other likely candidates as well:
- This type of outage should only happen occasionally. If you are having repeated outages in the same area and you suspect birds, you definitely have a problem.
- Inspect the area to see what might be attracting the birds, i.e. farms, grain fields, orchards.
- If there is a source of food nearby attracting large flocks of birds, sooner or later there's going to be an outage. Accept the fact that something will have to be done because this problem is not going to go away.
- You might as well be dealing with squirrels. There's no way to keep the birds off your equipment, so concentrate on protecting it, i.e. bushing covers, stinger covers, electrostatic guards, shields, and so forth.
- If your transformers resemble the picture on the left, you unfortunatly have a problem with Monk Parakeets.These birds are a relatively new problem for most utilities. If you have not yet read the section on these birds, we strongly urge you to click on the link and do so. We say unfortunately because several utilities have discovered dealing with this problem has resulted in creating a public relations nightmare for themselves. There is a certain logic to how this has come about. First, in the more temperate climates, the birds regard transformers as the perfect answer to their home central heating problems. Second, transformers are located near homes and businesses. Third, these birds are very appealing and are quickly adopted by the community. Fourth, the utility's "brutal, heavy-handed, and callous destruction" of the nests outrages the community. Fifth, newspapers are called, editorials are written, meetings are held, and accusations fly back and forth. The end result...hostile and angry consumers, a public relations black eye for the utility, and a potentially dangerous electrical problem. Even worse, we don't really have a good answer for this yet. Other, of course, than making sure the community is invited to particpate in finding a solution before anything is done. Right now, several groups are experimenting with coaxing the parakeets to nearby nesting structures. Ultimately, this may prove to be the best answer. Removing the nests without providing another site (nearby) is not always the best answer. These birds are sedentary and don't travel far. More than likely, they will simply re-build their nest as soon as possible.
- Raccoons - unlike squirrels, will climb poles. If the pole happens to have a transformer (or other overhead device) attached, the large size of the raccoon makes a phase to ground or phase to phase contact inevitable. Raccoons will sometimes survive such a contact and wander away, leaving behind little evidence of what happened.
- We don't understand this at all, but based on our survey information (details in the Manual), if you live in the northeastern part of the country, your most likely culprits after squirrels are cats.
- If your unexplained outages are occurring in older, congested urban areas in the South, more than likely your problems are rats. Black rats climb as well as squirrels (which is your clue for what to do) and will nest in the upper floors of buildings with easy access to overhead devices.
- Snakes will also climb on overhead devices, but, because of their tendency to wrap around things, what's left is usually still there when the crew arrives.
- You could install equipment protection (bushing covers, stinger covers, electrostatic guards, shields, and so forth) on all your overhead devices and just not worry about it. On the other hand you might take a less drastic (and less expensive) approach. If you're fairly certain unexplained outages are not being caused by squirrels, birds, or rats, climbing guards on poles work well.
If you would like some help in designing and implementing a comprehensive program for getting your animal-caused outages under control, drop us a line. Don't forget to check the Bulletin Board. If you don't see anything there to help, leave a questionand we'll post it. Be sure to check the Product Catalog to see what commercial products are available.