English
НАШИ ПАРТНЕРЫ:
НАШИ ПАРТНЕРЫ:
The most dangerous power transmission lines are those of voltage 6-10kV with upright insulators on ferroconcrete electric towers with metallic traverse. The developer of this construction is the institute “Selenergopoect” (Moscow). Such power transmission lines spread around the former USSR in the last half of the 20th century.
Biological incompatibility of such lines is caused by grounding connecting metal elements of the pylon into one chain.
Electrocution occurs at the moment of chain shorting when one or several birds happen to sit between the grounding element and the power line. The distance between the line and grounded cross-arm corner is about 15-25 cm which is comparable with size of a relatively small bird. Distributive electric networks made from this killer transmission lines have spread around the Russian Federation and now constitute a real danger to ornithofauna.
Let’s have a look at three variants of how birds can close the circuit:
1. A big (eagle) or a medium (rook, crow, buzzard, kestrel etc.) bird is sitting on the metal crossbeam (grounded traverse made of angle steel). When flushes it touches the current-carrying wire with wing, and the short circuit occurs.
2. A bird makes a step from the traverse to the insulator and touches the wire attached to it.
3. A young bird is sitting on the crosspiece. An adult bird comes with feed, sits on the insulator and the short circuit occurs when the adult bird passes the feed to the young bird.
About 90% of short circuits happen to young birds because their feather is very conductive.
