Fiber Optic & Transmission – OOPS!

Filed under:Brookings Routing Docket,Fargo-St Cloud,Hampton-Alma-LaCrosse,Reports - Documents — posted by admin on October 11, 2010 @ 8:13 am


This is in the OOPS! category.  Thanks to Tim Carlsgaard for reminding me of this report that I’d mentioned at a hearing recently — it’s got one of those technical findings that cracks me up:

The issue of safety of service personnel and the public arises in situations when low-voltage power is brought from a distribution system to the vicinity of high-voltage power lines to operate the electronic equipment. A fault or a switching surge on the high-voltage line may induce very high voltages in the low-voltage system.  This can cause damage to the equipment and also present a hazard to nearby humans.  In addition, concerns exist that the fault current flowing to ground in situations of high tower footing impedance can raise the potential of the local ground (GPR) to hazardous levels.  If the low-voltage supply system is also grounded at the fault location, the GPR can be transferred long distances through the low-voltage neutral (Transferred Potential) into the distribution system and into residences.  Experience has shown that these situations are rare, but can be very hazardous, leading to electrocution and residential fires, when they occur.  At this time, no obvious solutions can be suggested.

Here’s the full study:

EPRI – Fiber Optic Cables in Overhead Transmission Corridors