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for SBE Chapter 67 |
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These photos were taken at the Oncor powerline safety demonstration given at a meeting of SBE Chapter 67. Power lines are taken for granted by most people, and they look harmless most of the time. But power lines exist because they can deliver colossal amounts of energy. People of any age can be instantly killed, blinded or seriously burned by accidental contact with electric distribution lines. The purpose of the arcing demonstration is to show — in an unforgettable manner — the dangers encountered when high voltages contact wet branches, "decorated" kite string, construction cranes, or just hands and fingers. Broadcast engineers are especially interested in this, because TV news is gathered from all over town by the use of "live vans" that have 52-foot telescoping masts. Unfortunately, TV reporters and technicians have been killed or injured over the years when these masts have contacted overhead wires. People in the broadcast industry have learned (the hard way) that incidents like this must never happen because the results are always costly and sometimes fatal. The Oncor linemen also take these safety issues very seriously, as you might imagine. Their whole program was quite an eye-opener. (Click to enlarge.) 
The demonstration had just started at this point. This spark was probably heard on every AM radio within half a mile. 
The people in this crowd know exactly what they're looking at. Almost everybody on the back row stood up to get a better look and take pictures. The meeting took place on the loading dock at TXCN. 
Here's the reverse angle. TXCN's loading dock is huge, and the rest of their facility is really nice, too. 
Every arc is different -- some are brighter than others. 
Part of the demonstration showed that certain types of sparkly kite string have a thread of (what appears to be) aluminized Mylar wrapped around the load-bearing string. The linemen have a very low opinion of this stuff, since it appears to be about as dangerous as flying a kite on a wire. 
Linemen always wear 100% cotton shirts. This demonstration showed why they don't wear polyester blends. If a polyester shirt ignites, the fabric melts, it gets really sticky and makes a bad problem worse. 
Some of the "luminous discharges" were pretty spectacular. The perspective in this picture is a little misleading — the lineman was standing about five or six feet away from the energized conductors. |
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Document location http://www.akdart.com/sbe/index.html Updated July 31, 2007. Revision 2.3 Page design by Andrew K. Dart ©2007 ...with help from Travis. |