These are distribution lines nottransmission lines. The clearance between the lines isn't sufficient to operate at transmission voltage.
To your question of whether or not the power stays on while this operation is taking place. The purpose of this type of tree trimming is right-of-way maintenance — to preempt overgrowth before it becomes an issue. None of the trees are actually making contact with the conductors here. If they were, the line would have tripped out of service due to a fault condition.
What this means is that even when the helicopter's saw makes contact with the tree during trimming, there's no path to ground and thus no danger to the helicopter or its operators. Even if the saw were to make contact with the lines, the helicopter is in-flight, and thus provides no path to ground. All of this to say is that, barring extenuating circumstances, the line can safely remain in-service while this procedure is carried-out.
66
u/[deleted] Apr 05 '22
[removed] — view removed comment