Detection and disconnection of downed electric power lines of any voltage is a particular problem, even on multi-grounded wye-connected systems.
image/text credit: electrosnabzh
If the line is a secondary-level line from a distribution transformer the problem is compounded by the relatively low voltages and the high load currents that must be accommodated by any protective equipment during normal service.
For electricians, any minor mistake could be fatal. In this video an electrician is conducting routine maintenance on a power line when he comes very close to one of those fatal mistakes.
The worker was disconnecting a high voltage power line and once the disconnect was made, electricity can be seen shooting out trying to maintain the connection to one of the disconnected halves of the line. The worker just so happens to be mere feet from the stream of raging electricity.