Index:

• Pole Changes
• Brushing and tree-trimming
• Installing insulators in guy wires
• Excerpt from Safety Codes: Tree-Trimming

Brushing and tree-trimming

Trees are a blessing.  They are beautiful; but when they grow into
power lines  they not only become a nuisance,
they develop into an expensive and dangerous problem.

Brushing and tree trimming need to be done every three years in the area covered by the Bruderheim REA.  It is hoped that by doing that the problems caused by trees that touch power lines can be avoided.  However, that doesn't always work that well.

This year we must do brushing in our area.  A contractor does that for FortisAlberta.  Fortis will then bill the Bruderheim REA for the brushing that will be done.  The work is being supervised by Fortis, but the directors of the Bruderheim REA also keep an eye on things.  As of now we don't have a clear idea of how much money we will have to spend on that this year, but we expect that the bill for the brushing under the power lines will be in the order of $45,000 to $50,000 – it usually is in that range.  That means a cost of $100 to $110 that needs to be recovered from each member of the Bruderheim REA.  Last year it looked as if we would be spared a big brushing bill this year, but the crops are not the only thing that grew well this year; trees did too. 

The trees growing into the power line shown above were trimmed back three years ago, but now many already touch the power line, and, if left alone, next year many more would grow into the power line, just as some trees on that piece of power line already do.

How much a tree grows in a given year depends on the weather.  It also depends on the species of tree that is doing the growing.  For example, spruce trees grow an average of about one foot per year, and black poplar can grow by as much as three feet or more in a given year.

A number of concerns arise when trees grow into power lines. First of all, there is the safety issue.  People have been killed by touching or pruning trees that in turn touched power lines, especially when the power lines touched by the trees are on the high-voltage side of a transformer that serves a property.

In the picture on the right it can be seen that an aspen growing right next to a power pole along the road is being trimmed by a power line; its top branched are being burned off.

Some may think that is a good solution, that it saves work.  The problem is that it is not safe and that it makes for substandard quality of service. 
   Not only people but even more likely cattle can be killed by rubbing against that tree, and there are many other trees along this stretch of line that are just as close.  That means that if there is ever a load of frost or frozen rain on that line, the power line can no longer burn off all of the branches touching it.  It will then sag a good amount and touch all of those trees at once.  At the very least a switch will trip because the line becomes shorted out against ground.  At best, the voltage on that line becomes very noisy, and all the people served by that line will have serious problems with TV and radio reception because of the noisy line voltage serving their homes. 
   It is quite possible that sensitive electronic equipment served by a noisy and insecure power line will become damaged when the circuit breaker protecting such a line pops.  A circuit breaker will re-set itself if the current-flow on that line increases for only a very short interval.  However, if the excessive current-flow exceeds the specified time limit, the circuit breaker will trip and stay off, making it necessary that a line man comes out to investigate and to eliminate the source of the problem causing the service interruption.  At times it will be necessary to do brushing on that portion of the line.  The work required for that is a cost over and above the cost of the regular brushing program cycle.

There is another problem when trees touch power lines.  Energy gets lost.  It is known how much energy is being delivered into the distribution system of an REA.  It is also known how much energy is being used, collectively, by all consumers of electric energy in an REA.  There is always more energy being delivered into the distribution system than the consumers served by the distribution system use.  The net-difference between what is being delivered and what is being metered as consumption is called unidentified energy.  It is unidentified because it is not being measured where it is being lost.  It is lost through electrical resistance in transmission- and distribution lines.  At times some of it is being lost because it is being stolen, but a large portion of that unidentified energy is being lost by flowing through circuits we don't want, circuits that are being established through trees that are touching power lines. 

By the way, unidentified (un-metered) energy is also being used up legally and through deliberate design, through pumps on oil wells and through street lights.  The electric energy for pumps on oil wells is being estimated and billed to the oil company operating a given well.  Of course, those bills are just estimates, and the difference between estimated and actual power consumption is being added on to the power bills for all metered services in Alberta.  The power used by street lights is not being metered.  It is being estimated, too.  That power is being added on to and distributed over all of the bills for metered electrical services.  Yes, that means that people being served by rural services, even those that never see the light of a street light, pay for the energy all of the street lights in use in Alberta.

The producers of electric energy get paid for all of the energy they deliver into the transmission system.  They get paid even for the energy that is not flowing through the meters installed at the service ends.  The cost of energy that is lost in transmission- and distribution lines is being paid for, and the cost of that unidentified energy has traditionally been 3.5 percent of the energy consumption cost on our bills.  Moves are under way to increase the allowance for unidentified energy to close to seven percent of end consumption that is metered. 

If a lot of trees are touching the power lines in the distribution system of an REA, that will give the utility corporations more ammunition in their applications for rate increases that are to cover a doubling of the allowance for the recovery of the costs of unidentified energy.  All rural consumers suffer in many different ways, increased energy costs being a major portion of that, when trees are touching power lines.

It would be nice if trees could be trained to grow around power lines, as the spruce on right side of the picture on the left is trying to do, but it will be no more successful doing that than its neighbour to the left.

The farmer that owns the land on which the right-of-way for the power line illustrated here is located doesn't want the brushing contractor to clear the right-of-way.  He wants the contractor to use the bucket from the road to trim the trees under the line running along the edge of his property. The result of that is that every one else on the same circuit periodically gets an ear-full of noise when listening to the radio (or a lot of snowy bands running across their TV screens).  At times they will lose their power completely and will have to wait until Fortis manages to send a service man out to put the tripped switch back into the on-position.  Maybe that is all it will take, but for everyone along that line that operates sensitive electronic equipment, be prepared for power hits and outages.  They should buy surge protectors for all of their electronic equipment, and, if operating any kind of computer, buy an non-interruptible power supply for it.  Such a power supply can be had for about $200 to $300 and will provide them with about five minutes of time after the power goes off; during which time they may be able to manage to shut their computer down in the normal manner instead of having its programs and files corrupted when the power is lost.

Sometimes a tree falls onto a power line, or perhaps it may be even just a branch that broke off and got stuck that shorts out the power supply if there is also a neutral wire; and that little branch is often hard to see, especially at night.  Power outages are never nice to experience; needlessly frequent ones are a truly expensive frustration.

There is the cost of that "repair" job, a job that may be nothing more than to get rid of that fallen tree or of the hard-to-find branch.  All of the members of the Bruderheim REA pay for those jobs, and all of the members pay for the three-year cycle of never-ending tree trimming, because the man that owns the land on which the right-of-way is located doesn't wish to have a "road along the inside of his fence".  Yet, if the trees were to be cleared right down to the ground, with relatively cheap spraying every three years as well, the line put in danger by so many trees growing into it would perform to everyone's greater satisfaction and would cost everyone a lot less in terms of money and aggravation.

Similar issues come into the picture where a tap off the main line leads to the transformer in a farm yard.  There it is often an even more hotly contended issue, as people often strongly wish to have the trees left alone that cause power problems in their own yards and for their neighbours.  That cannot be done, neither practically nor legally, but there are ways to isolate a tap, so that when it fails, only that tap will be affected, although even that solution will do little to cure line-noise problems.  That is being discussed on the next page.