Why do the birds do not hit on the current transmission line conductors
Watching fun singing birds sitting on power lines energized wires, probably every one of us asked, 'Why does not hit the birds current? In this article I will discuss and explain why there is so.
Background theory
In order to understand the essence of the processes, it is necessary to go back to school a little and remember that this current, voltage and resistance. I understand that it's boring, but without it would be incomprehensible to a conclusion, so be patient and read carefully.
Thus, according to the current standard theory - is none other than the ordered motion of charged particles (electrons).
The main current flow in the conductors condition is the presence of potential difference (voltage) between two points of the chain.
A resistance - a physical quantity which just prevents the passage of electric current. The reciprocal of resistivity is conductivity, which is dependent on the length, cross section and conductor material.
Thus, the resistance of the conductor is calculated by the formula:
R = (I * p) /S,
where I - the length of the conductor;
S - section of the conductor;
p - resistivity (table value).
So, with boring theory completed and proceed to explain what's going on with birds on wires.
Birds on wires - what is wrong with them
So we see serenely sat birds on the wires under voltage. So, to understand why they are so calm and do not fall to the ground scorched remember that the current flows through the path of least resistance.
And our birds is allowed to present in the form of resistance chains which are shunted wire, that is, resistance of bodies of birds is much higher than the resistance wire and almost all of the current flowing through the wire is, rather than through feathered carcass.
Current flows through the wire, and the bird becomes a potential that is equal to the voltage line.
Curious. It is worth noting that the birds are trying to stay away from power lines of 220 kV and above, and in a rather wet weather and 110 kV sidestep. Specialists attribute this to the fact that the lines formed near electromagnetic field of high intensity, as well as corona discharges.
The conditions under which the bird will get an electric shock
Now let's consider a situation where a bird will come under pressure. So, we know that the current flow necessary potential difference. It turns out that the bird must be simultaneously touch two wires at once, it will lead to phase short-circuit.
Of course, the sparrow will not do so, because he has not corny enough wingspan. Such action can only fairly large birds. Of course, if the cords are covered with insulation, then in any case the bird does not get an electric shock, as the insulation is sufficiently high resistance.
The real problem, "bird" blackouts
As long as we all believe birds completely impervious to electric shocks on the HV, the statistics indicate that it is not so.
Here, for example, carried out in the suburbs studies have shown that an average of 10 km line are up to 150 birds with signs of electrical stimulation. Birds still as fall within the punches electric current.
So it should be noted that energy is not harmful to the birds themselves, and their droppings, which is getting on the insulators, causing them to overlap. A consequence of this fault.
The PUE is even a paragraph 5.7.10, according to which in places of mass gathering of birds, forming strong contamination of insulators, as well as in places of nesting should establish specialized dispersing adaptations.
Fight against this phenomenon by the use of insulators with the special "umbrella"
It is also a big problem cause nesting attempts on support, the only way to fight is to install special platforms for nests.
conclusion
As can be seen, "invulnerability" of birds is only a myth and, under certain conditions, these "gatherings" are a real headache of Power. Now, watching a flock of peaceful jumping on the wire Sparrows you perfectly understand why they do not get an electric shock.
Thanks for attention!