Ground currents associated with trees on power lines

[canadiantreeman]

It is never a good time when working with those who are not aware of the potential hazards in the business that just assume we can get it done with no or little collateral damage. However, that is our job. Would it not be prudent to schedule a meeting with this gentleman, for which you were highly prepared, and speak to him about the concerns you have? Even if you offered to buy him a coffee or a beer and discuss it off the clock? I'd bet if a certain amount of charm and enthusiasm for safe work procedure was brought to the table, the fella might come around to see your side of the story.

 

[SouthSoundTree]

It sounds like you are unhappy because there is no hazard mitigation plan. Forget how the tree is going to get cut and pulled for now. You have two options, both include traffic control. 1. Get the utility company to put the lines on Non-reclose, they will do this on lines under 35Kv. 2. Get the lines down, Sometimes you can meet resistance from the utility particularly if there is a business that can't lose power or a homeowner with special needs.

As for the tree. You have a skidder, you have blocks, it is a Doug fir. Dead or not if the wood is sound you can pull it pretty much wherever you please.

Unhappy about being micromanaged by someone that doesn't understand the work.




With a good hinge, this is more the case. With a laminated root rot pocket, the concern is that the hinge will not be sound enough. The skidder is a great too, but small. There are other trees in the area that could get knocked down, possibly into the power lines, if we were to try to go parellel.

The main question is not about getting the tree down, but having a good backing to our reasoning when management wants us to do something that they don't really understand. Micromanagement without understanding the whole equation.

It takes more time and financial resources to move the skidder than bringing the jacks, so sometimes its just a better option to get the same objective done.

 

[SouthSoundTree]

Back to the point you made on being concerned about dynamic loading of a restraint line to hold against what would amount to side lean in this scenario, Sean...

That shouldn't really come into play, I'd think. The line would be pre-loaded. There would have to be some slack that was then taken up to generate a dynamic load, no?

I know this isn't really the point of the thread at all, sorry to go tangential on it .

We haven't tried to use a MA on the Amsteel. Seems really slick, and might be hard to get fully preloaded. If the lay isn't an exact 90 degrees, seems like it might get dynamically loaded. That type of super static fiber doesn't do well with any shockloading. We are on a supertight budget, and would be hard pressed to replace it at this point in time. Its a very important tool to have for other pull trees.


We didn't look too much into the how of we'd get it down, as it really doesn't need to come down right now, but don't tell that to the Ph.D. with laser range finder and some rule about tree heights in relation to structures.

Giving an anecdote of a person getting killed by a ground current from a tree failing onto a power line would be enough to defend our decision not to remove a tree in an area that will get logged in time, as the whole area is shot. Mostly DF in a laminated root rot pocket.

We have lots of more important work to do that poses higher risk to people and property that this tree which can be taken care of in a few months by the loggers with bigger equipments, and who will clear out the other OG trees that are in the way of just going opposite the lean.

The manager is concerned about lots of things, "A" is really important for us to accomplish, except come do "B", but pull off of that and do "C", but wait, I want to re-examine "D". Did you do "A"? I don't understand, why not.

 

[SouthSoundTree]

It is never a good time when working with those who are not aware of the potential hazards in the business that just assume we can get it done with no or little collateral damage. However, that is our job. Would it not be prudent to schedule a meeting with this gentleman, for which you were highly prepared, and speak to him about the concerns you have? Even if you offered to buy him a coffee or a beer and discuss it off the clock? I'd bet if a certain amount of charm and enthusiasm for safe work procedure was brought to the table, the fella might come around to see your side of the story.

Yep, trying to get some good backing based around safety for this and other situations. Ph.Ds be so sure of what they figured is right.

He can be one to say "just". Can't you just fell the 100-150' trees with root and butt decay into a really tight lay without dropping them on each othert, or the infrastructure, but don't move any of them out of the way. We don't want to break any logs that would result in decreased value at the time of a timber sale.

 

[wiley_p]

Again. If the lines re put on Non-reclose, then there is no chance of electrocution. Also there is such a thing as trees that cannot be felled or situations that are beyond ones current skill level. You will always run into problems with folks who bid a job, or write up a work plan. It is your job as the guy in the field to find a safe way to do the work, or communicate to management the objective hazards and risk involved.

 

[canadiantreeman]

Again. If the lines re put on Non-reclose, then there is no chance of electrocution.

I'm not sure that's the case. I am of the understanding that a non-reclosure prevents the system from attempting to restore power, but that the initial contact would still be a dangerous situation. Especially if the contact is direct. I am of the understanding that the non-reclosure is more a means to protect the power system itself, rather than those working around it. The only way to eliminate the potential for electrical contact would be to have the line dropped, from what I understand.

 

[Al Smith]

Depends on the system. On some the reclosurer circuit bangs the OCB--oil circuit breaker back in three times over a set period of time .After which it has to be manually reset

Distrubution high voltages within the confines of a large industrial complex have combination of differential sensing circuitry and time over currents that generally have to be manually reset before reentergizing .

If it's on a set of air break fuses once they blow there is no manual reset . Gotsta put in a new fuse .It would again depend on the area and the situation as to what it has .

 

[wiley_p]

I'm not line clearance, but I have had it done several times and the way it was explained to me was that if I contacted the lines with part of the tree it would kill the juice and it would have to be manually turned back on. I think the normal when there are trees that could contact the lines in normal wind it resets a few times like Al said. luckily I never crushed the lines yet, just had it done so no one could get killed.

 

[Al Smith]

That's basically what the three reset is for .However it's likely set up with a differential or time over current also in case of a downed line .

It's part of the biz called high voltage relaying .A subject not many know about .I know just a little and that is more than most electricians .

You get into situations called cascade if things aren't set up properly .It was but a few years back that a situation blacked out the whole of the east coast and part of Canada and was traced to one tree that took out an insignificant feeder line in PA .Now how would you like to pay that bill ,heavens

 

[SouthSoundTree]

Again. If the lines re put on Non-reclose, then there is no chance of electrocution. Also there is such a thing as trees that cannot be felled or situations that are beyond ones current skill level. You will always run into problems with folks who bid a job, or write up a work plan. It is your job as the guy in the field to find a safe way to do the work, or communicate to management the objective hazards and risk involved.

Agree on all points, Dave, except for the non-reclose, as I don't know anything about this part. Any additional info is welcome, for general learning.

Sometimes the most difficult part is convincing someone who is "right" (supervisor).

 

[Al Smith]

I'll tell ya what ,if you don't feel safe doing it don't .I've worked around high voltage off and on for 40 years and I highly respect it .Seldom do you get a second chance if you get nailed .

 

[SouthSoundTree]

YEP.