High Voltage Line Maintenance from Helicopter Videos for Engineers
of radio tower climbers are cool for sure. Fear of
heights notwithstanding, the physical strength and stamina required to scale 1,000+-foot towers is more
than most people could endure. Winds aloft are typically stronger and more gusty than at ground level, so the
shaking of the tower would unsettle all but the most robust stomachs and inner ears. Their bravery helps assure
that communications worldwide continue nearly uninterrupted. There is another cadre of aerial linemen that deserve
attention - the guys who ride on helicopter skids to maintain and repair high voltage transmission lines.
One of the coolest parts of the video is where the lineman uses a metal wand to draw an arc from the power line
(often at 100 kV or more) in order to bring the helicopter environment to the same potential as the line. A
bonding cable is then clamped to the wire to maintain a 0 V difference of potential. Once situated, the lineman
and heli enjoy the same immunity to shock as do squirrels running along the 1-30 kV overhead line running along
the streets. No difference of potential = 0 A of current. Of course the skill of the pilot flying the helicopter
has to be extremely high in order to maintain such a precise hover in the presence of wind gusts. It wouldn't take
much to cause the tail boom to swing into line in just the wrong set of conditions.
In these two videos,
the linemen are dropped off and then picked up after completing their work. There are instances where the
helicopter must hover for many minutes in the same spot while the lineman sits on a platform attached to the skids
to perform the maintenance. Although not always the case, former military pilots often get these jobs because of
the rigorous training they received in flight school.
Helicopter Transferring Lineman to Wire
Helicopter & High Voltage Power Line Maintenance in South Africa