Lightning protection and lightning protector
In each instant in different points of Earth lightnings more than 2000 thunderstorms sparkle. In every second about 50. lightnings hit to the Earth's surface, and on average each its square kilometer the lightning strikes six times in the year. The lightnings beating on the ground from storm clouds are the electric discharges transferring to it the negative charge size several tens the Coulomb, and current amplitude at the lightning discharge is from 20 to 100 kA.
The system device of protection against the lightning (lightning protector) will provide you and your property with safety in the building, the house or office.
According to average data in the terrestrial world, every year there are about fifteen million thunderstorms posing high danger for human life. Unfortunately, practice shows frequent cases when the lightning kills the person, at the head-on impact in heart or in other vitals. In order to avoid hit you in tragic statistics we strongly recommend to organize safe working conditions at office and life of and relatives, in the house.
At the time of the head-on impact of the lightning in the construction object correctly designed and built lightning protection device has to assume the lightning current and take away it to the earth. The current flow of the lightning has to occur without prejudice to the protected object and to be safe for the people who are as inside, and outside of this object. Now even more often there are new requirements imposed to lightning protection devices such as:
- Restriction in the object of size of the pulse electromagnetic field created by the lightning current.
- Creation of lightning protection installation of the esthetic look, on the objects constructed of diverse materials.
Modern lightning protection ensures safety of the building not only at direct hit in the object, but also from remote discharge which is the most dangerous. The systems of lightning protection can be separated on active and passive.
Passive lightning protection is used about 300 years for protection of buildings against impact of the lightning. Some specialists call this type of lightning protection "classical". It represents the system of metal interception rods, metal lightning arresters and grounding conductors. Passive lightning protection practically forms the artificial channel for course of current to the earth on the shortest way.
Active lightning protection – the way of lightning protection which appeared rather recently. Recently gains the increasing popularity. Active lightning protection constantly generates short electric impulses between the thundercloud and the lightning arrester, and, thus, artificially creates the channel of air with the low resistance.
Active lightning protection system is more modern and consists of one interception rod which can ensure safety not only buildings, but also the territory surrounding it. However, "active" lightning protection attracts lightnings and therefore probability that near the building lightnings will constantly beat, considerably increases. At the wrong installation of system it can lead to melting of everything that has the closed circuit (for example, metal rings and pipes), to burning out of wiring and electronics. One more lack of system of "active" lightning protection can be considered possible violation of architectural identity of the building and more considerable costs of installation.
Modern technologies of systems of protection against the lightning do not come to an end on one protection against the lightning discharge. Unfortunately not all know what occurs at the time of the blow. Therefore in good intentions we will focus attention on effects of the blow. This century with the prompt speed increases pace on development of information and communication technologies, and similar technical objects are subject to danger of influence of the electromagnetic field arising as a result of strong electric discharge. The electromagnetic field forms the overload of power chains, the microprocessor equipment because of what there can be not the justified operation of security alarm systems, unexpected failures in the information equipment up to the exit from under control of nuclear reactors on strategic objects is subject to big risk.
The lightning protection system consists of elements of external and internal lightning protection.
What is represented by external lightning protection system?
It is system which helps to protect the house, the building, educational schools and productions from the fire and any damages at lightning discharge blow. The lightning protection system instantly does interception and takes away current from the lightning to the earth. Withdrawal of current is provided with the principle of work of the receiving lightning of the grid which is initially projected by specially trained developers, under each certain building of production or houses. If the system of lightning protection is correctly built and designed, then at the moment when the lightning or the thunderstorm to the building strikes, the system will undertake current then it will take away on the developed current taps which will be located on grounding. In this way current has to pass so that passing of discharge of the thunderstorm or lightning was undergone on the receiving grid and then in the current tap without infliction of harm to the building and in it the being people.
In structure of external lightning protection system, enters:
- First, it is the grounding conductor which is carried out among themselves, in the electrical link through conducting medium or contact with the earth.
- Secondly, descents, that is current taps the being body, which problem to take away current of the thunderstorm or lightning in the grounding conductor.
- Thirdly, this system device which is the lightning arrester it intercepts jolt of electricity of the lightning or thunderstorm and sends it, via the current tap to the grounding conductor which is manufactured of corrosion-proof metal (copper, galvanized steel or aluminum).
And now we will talk about the internal system of the lightning protection device.
The internal system of lighting protection consists of the tire of alignment of potentials which integrates all extended metalwork of the house, in particular connects the power supply network neutral to the ground loop, screens television cables, the pipe of water supply and heating with the ground loop, lightning protectors and the metalwork with the ground loop.
The internal systems of lightning protection are the package of measures and technical devices which problem is alignment of potentials. The Otimpulsny retension caused by the electromagnetic field of the lightning devices of protection of the equipment against the pulse retension (UZIP) are used. Varistors and gas dischargers kind of "short-circuit" the protected line, thereby interfering with impact on the equipment of the pulse overstrain. The transmission line and distribution nodes it is possible to secure by means of valve dischargers or the limiters of the overstrain of nonlinear (LON) which establish on the entrance to substations or on tires.
It helps to reduce tokomagnitny, effective impacts on people, the equipment and installations and also on the construction objects which are indoors. Further, the stated text will be provided, only the most important issues of internal lightning protection. For example, such as equalizing of potentials in the construction object, placement and selection of devices and, of course, from the direct impact of the part of the lightning or current on the person.
The most important principles of equalizing of potentials are kept in construction objects of lightning protection. In this case, it is necessary to follow the principles, to equalize all carrying-out installations in the necessary object.
Equalizing should be carried out by means of special connections which are equipped with the low impedance. It is separated into two categories, belong to the first category: direct which are carried out between the carrying-out devices electric potential does not arise installations and among them. Treats the second category: limiting, that is are carried out between the devices isolated and grounded from the earth and also in reliably covered place from wires which are under the big tension.Top