posted on Mar, 25 2013 @ 09:30 PM
I'm in the energy business and this sounds like a typical overhead HV feeder fault (something like 11kV to 33kV) that can be a failed insulator,
possum, bird, conductors clashing due to a vehicle hitting a pole, wind causing conductors to clash or tree branches touching a phase etc. It
doesn't take a pole transformer exploding which is a very rare event compared to my other possibilities and the flash is brilliant, lighting up the
entire sky particularly when there's some cloud cover. I've seen them myself and it's quite spectacular plus I was in a position (my job) to find
out exactly where the fault occurred.
These feeders usually have auto-reclose relays on the circuit breakers at the source which reclose the circuit breaker a set time after the trip
(normally 10-60 seconds or so) and if the breaker trips again on the reclose due to the fault still being detected, the protection locks the breaker
out requiring a patrol to identify and clear the fault plus reset the protection before a manual attempt at restoration can be done. Some very remote
areas can be arranged to have multiple auto-reclose shots in places where animals on the lines are very common and it takes hours to organize a patrol
to get to the site (hoping to blast the fault off and not require a team out in the wilderness at all hours of the night). Despite possum guards on
the wood poles and special construction to reduce large birds causing faults we still get many such faults every day in bushy areas with 90% or more
of auto-recloses being successful.