Lightning protection
Lightning protection (lightning protection, lightning protection) is a set of technical solutions and special devices to ensure the safety of the building, as well as the property and people in it. Up to 16 million thunderstorms occur annually on the globe, that is, about 44 thousand per day. Danger to buildings (structures) as a result of a direct lightning strike can lead to:
- damage to the building (structure) and its parts,
- failure of electrical and electronic parts located inside,
- death and injury to living beings located directly in the building (structure) or near it.
Lightning protection of buildings is divided into external and internal.
External lightning protection system
External lightning protection is a system that intercepts lightning and diverts it into the ground, thereby protecting the building (structure) from damage and fire. At the moment of a direct lightning strike on a construction site, a properly designed and constructed lightning protection device must absorb the lightning current and conduct it through down conductors into the grounding system, where the discharge energy must be safely dissipated. The passage of lightning current must occur without damage to the protected object and be safe for people located both inside and outside this object.
There are the following types of external lightning protection:
- lightning protection network;
- stretched lightning wire;
- lightning rod.
In addition to the above-mentioned traditional solutions (given both in the international standard IEC 62305.4 and in the Russian regulatory documents RD 34.21.122-87 and CO 153-343.21.122-2003), since the mid-2000s, lightning protection with an early streamer emission system, also called active lightning protection. The use of this system is regulated by several standards, primarily the French NFC 17-102.
In general, external lightning protection consists of the following elements:
- Lightning rod(lightning rod, lightning rod) - a device that intercepts a lightning discharge. Made of metal (stainless or galvanized steel, aluminum, copper)
- Down conductors(descents) - part of a lightning rod designed to divert lightning current from the lightning rod to the ground electrode.
- Ground electrode- a conductive part or a set of interconnected conductive parts that are in electrical contact with the ground directly or through a conductive medium.
Lightning protection of power lines
Internal lightning protection system
Internal lightning protection is a set of surge protection devices (SPDs). The purpose of the SPD is to protect electrical and electronic equipment from overvoltages in the network caused by resistive and inductive couplings that occur under the influence of lightning current. It is generally accepted to distinguish overvoltages caused by direct and indirect lightning strikes. The first occurs when lightning strikes a building (structure) or communication lines connected to the building (structure) (power lines, communication lines). The second - due to strikes near a building (structure) or a lightning strike near communication lines. Depending on the type of hit, the overvoltage parameters also differ.
Overvoltages caused by direct impact are called Type 1 and are characterized by a waveform of 10/350 µs. They are the most dangerous because they carry a lot of stored energy.
Overvoltages caused by indirect shock are called Type 2 and are characterized by a waveform of 8/20 µs. They are less dangerous: the stored energy is approximately seventeen times less than that of Type 1.
SPDs are classified accordingly.
Regulatory documents
In Russia, a difficult situation has developed with regulatory documents regulating the requirements for lightning protection of buildings. At the moment, there are two documents on the basis of which you can design a lightning protection system.
These are “Instructions for lightning protection of buildings and structures” RD 34.21.122-87 dated July 30, 1987 and “Instructions for lightning protection of buildings, structures and industrial communications” CO 153-343.21.122-2003 dated June 30, 2003.
In accordance with the provisions of the Federal Law of December 27, 2002 No. 184-FZ “On Technical Regulation” Art. 4 executive authorities have the right to approve documents and acts of a recommendatory nature only. This document includes the “Instructions for the installation of lightning protection of buildings, structures and industrial communications” CO 153-343.21.122-2003.
Order of the Ministry of Energy of Russia dated June 30, 2003 No. 280 does not cancel the previous edition “Instructions for lightning protection of buildings and structures” dated July 30, 1987. Thus, design organizations have the right to use the provisions of any of the mentioned instructions or their combination when determining the initial data and when developing protective measures.
The design process is complicated by the fact that none of these instructions covers the issue of using lightning and switching surge protection devices. The old version of the instructions did not provide for such a section at all, and the new CO 153-343.21.122-2003 covers this issue only at the theoretical level; no instructions are provided for the practical use of protection devices. All issues that are not covered in the instructions themselves are prescribed to be considered in other regulatory documents on relevant topics, in particular the standards of the IEC organization (International Electrotechnical Commission).
In December 2011, the Federal Agency for Technical Regulation and Metrology issued GOST R IEC 62305-1-2010 “Risk Management. Lightning protection. Part 1. General principles" and GOST R IEC 62305-2-2010 "Risk management. Lightning protection. Part 2. Risk assessment." These documents represent the authentic text of the IEC 62305 standard, consisting of four parts, and are intended to clarify the situation with lightning protection systems on the territory of the Russian Federation.
Types of SPDs and typical application schemes for internal lightning protection
Surge protection device
Surge protection devices (SPDs) are divided into type 1, type 2 and type 3.
Type 1 is capable of transmitting all the energy of a typical lightning strike without being destroyed. But, a type 1 device retains a fairly large voltage surge (a few kilovolts).
Typically Type 1 is only installed in rural areas with overhead lines. The guidelines require Type 1 in buildings with lightning rods, as well as in buildings connected by overhead lines, and in buildings that are free-standing or adjacent to tall objects (trees).
Type 2 is not capable of independently, without the preceding type 1, withstanding a lightning strike without destruction. However, its survivability is guaranteed if used together with type 1. The surge voltage behind type 2 is usually about 1.4-1.7 kV.
Type 3 for its survivability requires the use of types 1 and 2 in front of it, and is installed directly next to the consumer. It can be, for example, a surge protector or varistor protection in the power supplies of some household devices (automation of heating boilers).
The SPD does not protect against long-term overvoltages, for example, from an increase to 380V during a “zero burnout”. Moreover, long-term overvoltages can lead to SPD failure. In the event of a through burnout of the SPD from phase to PE, a huge amount of heat may be released on it and a fire may occur in the panel. To protect against this, the SPD must be installed with protection - fuse links or circuit breakers.
In the case when the input “machine” has a nominal value<= 25A, возможно подключение УЗИП за ним, в этом случае вводной автомат также выполняет функции защиты УЗИП.
Lightning protection schemes are implemented either with safety priority or with uninterruptibility priority. In the first case, destruction of SPDs and other devices is unacceptable, as well as a situation where lightning protection is temporarily turned off, but automatic operation with a complete shutdown of consumers is acceptable. In the second case, a temporary shutdown of lightning protection is acceptable, but an interruption in supply to consumers is unacceptable.
When installing type 1 and type 2 simultaneously, the distance between them along the cable must be at least 10 m, the distance from type 2 to type 3 and consumers must also be at least 10 m. This creates the inductance necessary for the machine of a higher stage to operate earlier. It is also possible to use SPDs of types 1+2, which combine both devices in one housing (protected from burnout in the same way as type 1).
SPD devices have different designs for different TN-C, TN-S and TT systems. It is necessary to select a device for your grounding system.
See also
Notes
Links
- FAQ on lightning protection. Archived from the original on March 27, 2012. Retrieved October 29, 2011.
Wikimedia Foundation. 2010.
Synonyms:See what “Lightning protection” is in other dictionaries:
Lightning protection… Spelling dictionary-reference book
lightning protection- A system of protective devices used to protect buildings and structures from accidents and fires when struck by lightning [Terminological dictionary of construction in 12 languages (VNIIIS Gosstroy USSR)] QUESTION: WHAT IS LIGHTNING PROTECTION... ... Technical Translator's Guide
- (a. lightning protection, lightning discharge protection; n. Blitzschutz; f. protection contre la foudre; i. proteccion contra royo) a set of measures and technical. means for the protection of buildings, structures, equipment and electrical... ... Geological encyclopedia
Noun, number of synonyms: 2 lightning grounding (1) lightning protection (1) ASIS dictionary of synonyms. V.N. Trishin. 2013… Dictionary of synonyms
LIGHTNING PROTECTION- a set of measures and means to ensure the safety of people, the safety of buildings and structures, equipment and materials from direct lightning strikes, electromagnetic and electrostatic induction, as well as from the introduction of high potentials through... ... Russian encyclopedia of labor protection
lightning protection- rus protection (g) from lightning surges, lightning protection (g); lightning protection (g) eng lightning protection fra protection (f) contre la foudre, protection (f) contre les décharges atmosphériques deu Blitzschutz (m) spa protección (f) contra rayos … Occupational safety and health. Translation into English, French, German, Spanish
Same as Lightning Protection... Great Soviet Encyclopedia
Lightning protection, a set of technical measures. means protecting buildings, structures, as well as electrical devices from damage due to direct lightning strikes. Lightning protection devices include lightning rods, arresters, etc... Big Encyclopedic Polytechnic Dictionary
A system of protective devices used to protect buildings and structures from accidents and fires when they are struck by lightning (Bulgarian language; Български) lightning protection (Czech language; Čeština) ochrana proti blesku (German language;… … Construction dictionary
lightning protection- lightning protection, s... Russian spelling dictionary
A lightning strike is a natural phenomenon. And it is absolutely clear to everyone that it is random in nature: it may hit, or maybe it won’t! However, if it does get hit, the consequences can be very sad.
Example one: At the edge of the forest, not far from a picturesque lake, there is a log house. Solid, cozy, with a metal roof. During a strong June thunderstorm, lightning strikes the roof of the house...
But before we continue, we must say just a few words about the physical essence of lightning. When lightning “starts” from a thundercloud, the direction of its development is determined by the so-called leader. It is almost impossible to predict the trajectory of its movement; sometimes it is only possible to guess with a certain degree of probability the end point where it is heading. The lightning leader can be figuratively compared to a needle followed by a thread. The thread in our case is the so-called lightning channel. At its core, a lightning channel is highly ionized air heated to several thousand degrees, forming an ideal conductive medium between a cloud charged to very large potential differences and the surface of the earth. Pulse currents of enormous magnitude (up to hundreds of kiloamperes) begin to flow in the lightning channel, the main task of which is to equalize the potential difference existing between the cloud and the ground.
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Now let’s imagine that an obstacle has arisen in the path of lightning in the form of a cottage, a wooden house, or any other object (boiler room pipes, factory building, antenna mast of a communication facility, just a tall tree...). Having covered a distance of several hundred, or even more, meters, which would cost lightning to burn a hole in the metal tiles of the roof, at the same time frying the rafters, break through the insulation of the cable laid in the attic, causing a short circuit in the electrical wiring, and spread an arc or a fountain of sparks between the roof and the gutters pipes, and then in the same way to the ground, along the way, setting fire to the poplar fluff that did not have time to get wet... A terrible fairy tale can be told for a long time. But the scary thing is that sometimes a fairy tale becomes reality. Something similar happened to that house on the edge of the forest; the only thing that saved it from disaster was that the owners were at home and managed to put out the fire on the wooden roof structures! What if the house was empty at that time?! What if this happened at night... when everyone was sleeping?!
And now another case! And let at least someone say that he is insured against it, unless he has already learned from his own or someone else’s bitter experience, and has not provided all the necessary technical solutions to minimize the unpleasant consequences of a lightning strike. So: the construction of an elite residential building with a large landscaped area, fountains, gazebos, a tennis court is underway... It is clear that the cost of such a facility is very, very high. The planned internal engineering networks (electrical, air conditioning, smart home systems, security and video surveillance systems, etc.) match the appearance.
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During a thunderstorm, lightning struck a ship's pine tree, next to which an electric cable was laid in the ground to illuminate the walking path. Lightning currents, having damaged the cable insulation, penetrated through its metal conductors into the main distribution board located in a separate utility building. Having burned several circuit breakers along the way, they spread throughout all the electrical circuits connected to this panel, including penetrating into the premises of the automated gas boiler room, which had already been installed and in operation. As a result of only a small part of the total lightning current entering the controller (electronic control device) of the boiler room, it was immediately disabled. The cost of such a device can range from several thousand dollars or more. It must be said right away that the losses could have been much higher if all the systems listed above had been put into operation at this facility. It was saved by the fact that the residential building was still at the finishing stage and the electronic systems provided for by the project had not yet been installed or connected to the electrical power supply network.
Now the time has come to answer the first part of the question asked at the beginning of the article:
What is lightning protection?
Lightning protection refers to a whole range of technical solutions and special devices. First of all, an external lightning protection system must be installed on the house (see photos below). Its main element is one or more lightning rods. These devices may have different appearances, but they all must perform a very important task - to prevent lightning from reaching the surface of the roof and its elements, as well as to the facades of the building and the surrounding area. From lightning rods, several metal conductors called down conductors are lowered along the walls of the building. Their task is to divert the currents of caught lightning to special grounding devices located under the surface of the earth away from the entrances to the house and walking paths. Protection zones of lightning rods, locations of grounding devices and routes for laying down conductors are calculated by the designer of the facility's power supply systems. And it is very important that this is done at the stage of architectural design of the building with mandatory interaction with the architect. Then it will be possible to avoid many technological difficulties that will certainly arise (we already have sad experiences) when installing an external lightning protection system on a ready-made house, shining with fresh finishing materials! Then it will be possible to disguise as much as possible all the elements of this very important system for the house, so that they organically fit into its appearance and architecture!!!
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The photographs above show a house whose lightning protection system is made in the form of a so-called lightning protection mesh. Since the building has a somewhat complicated architecture, in addition to the mesh, additional pin vertical lightning rods are installed on the protruding elements of the roof structure, which should provide an increase in the protection zone from a direct lightning strike. There are several methods for calculating such a lightning protection system. In order to correctly place and install all its elements, it is necessary to contact specialists in this field, since otherwise its efficiency will be unacceptably low and will in no way correspond to the material costs incurred.
Its main element is the so-called active lightning rod. The principle of operation of such a lightning protection system is that an ionization area is created around the active lightning rod during a thunderstorm. And at that moment in time, when the electric field strength between the thundercloud and the surface of the earth reaches a critical value (i.e., a lightning discharge becomes inevitable), a counter leader (spark discharge) starts from the lightning rod towards the lightning already developing from the cloud. In the event that lightning continues its path to the protected object, it will certainly be “pulled” to the lightning rod (within its design protection zone). If it moves away from the protection zone, the active lightning rod will not have any effect on it. The advantage of such a lightning protection system is its relative ease of installation and minimal impact on the appearance of the house. The disadvantage is the lack of any domestic regulatory framework for its use. However, various designs of this type are widely used in the USA, France, the Baltic countries, Poland and many other countries. The main standard for the use of active lightning protection systems is the French standard NFC 17-102.
And in conclusion, be sure to note one very important thing. Initially, the operating principle of active lightning protection systems was based on the use of radioactive isotopes, which, of course, did not add to their popularity! Currently, such technical solutions are not used, but still, when choosing this very expensive technical device, ask the seller how it is designed and what its operating principle is, and if you do not hear anything intelligible in response, beware of buying it recklessly. God protects the safe!!!
So why do we still need lightning protection?
You probably already guessed it! Of course, first of all, to protect the house from fire in the event of a lightning strike! Having received a lightning strike, a system consisting of conductors reliably connected to each other will determine the most direct, easiest path for lightning currents to the point to which it so strives - to the ground! In this case, there will be no sparks, because there are no gaps through which it is necessary to jump in the form of a spark. The cross-sections of the external lightning protection elements are such that strong heating will not occur when very large lightning currents flow through them. Yes, and they are laid according to international and now Russian regulatory documents ("Instructions for the installation of lightning protection of buildings, structures and industrial communications", SO-153-34.21.122-2003), at some distance from the surface of the walls and roof, if they are implemented from flammable material.
With the first example, everything has now become clear. But what about the second case, when lightning strikes a tree, but in suburban areas this can happen all the time! And even more serious damage can occur if lightning strikes directly into overhead power lines, which is the main method of supplying electricity in rural areas. In this case, the main part of its currents will flow through the input device of your house and further, using all possible paths, to the ground. Who knows what kind of paths these will be, and what expensive equipment these currents may encounter along the way. In order to preserve modern complex and smart electronic equipment, it is necessary to place a reliable obstacle in the form of surge protection devices in the path of lightning currents. Together with the potential equalization system, which the designer must provide, they will create an internal lightning protection system for your home. Imagine this: a crow is sitting on a wire of an overhead power line. And even though large currents flow through the wires, even though high voltages are present, they do not cause any harm to the bird, because they do not flow through it. But this is all until it gets caught, carelessly flapping its wing, on a nearby wire. We won’t continue further... The same thing happens inside your home. A properly executed grounding and potential equalization system will avoid electric shock to people inside or near the house, including during a thunderstorm. Because there will be no points with different potentials inside the house, there will be nowhere for currents to flow. Surge protection devices (arresters, varistors, combined devices) provide short-term connection to the potential equalization system of those wires (electrical, telephone, television and other cables) that in their normal state are never connected to grounding. All currents that should have flowed through your household appliances will flow through the devices designed for this, which will protect them from electrical breakdowns. And then everything will return to its original state. You most likely won't even notice anything!!
A lightning discharge that strikes the structural elements of a structure is accompanied by an impressive electromagnetic effect. This, in turn, has the most negative impact on the functioning of electrical equipment. Designing a lightning protection system allows you to reduce damage to cable conductors and minimize the likelihood of an object being hit by a strong charge.
Structure
Lightning rod is a passive protective measure that ensures the safe operation of facilities, preserves the health and lives of personnel and residents during the destructive effects of natural disasters. Lightning protection systems consist of the following main elements:
- Discharge receiver.
- Down conductor.
- Ground loop.
Types of lightning protection
Currently, there are active and passive lightning protection systems. The traditional - passive version consists of a discharge receiver, a current-carrying element and grounding. The operating principle of such a system is quite simple. The lightning rod absorbs the lightning strike and then directs it to grounding through the conductive paths of the down conductor. Ultimately, the discharge is extinguished in the ground.
In turn, the active lightning protection system works according to the principle. Thanks to this effect, the discharge is intercepted. Active lightning protection systems consist of the same elements as passive ones. However, their range of action is much greater and reaches about 100 meters. In this case, not only the object on which the system elements are installed is protected, but also nearby buildings.
Active lightning protection is much more effective. Therefore, it is not surprising that this option is preferred by users in most developed countries. However, the cost of such solutions is much higher.
Options for discharge receivers
In the standard version, the full receiver is a regular metal pin that is mounted in a vertical position on the roof of the structure. It is extremely important to secure this element at the highest, open point of the roof. If the building has a complex roof structure, in terms of increasing the level of safety, it is recommended to install several discharge receivers.
There are separate options for lightning rods, which differ according to their design:
- Pin protection.
- Metal cable.
- Lightning protection mesh.
Pin protection
If the structure contains a metal roof, then the right solution would be to install a pin lightning protection system. The discharge receiver in the form of a standard metal rod is installed on a hill. The latter is connected to grounding through down conductors.
Pin protection can be presented in the form of a round metal rod with a cross-section of at least 8 mm or a strip piece of metal with parameters 25 x 4. The length of the element receiving the discharge should be such that its end rises above the highest point of the object by approximately 2 meters.
The ability of the lightning protection and grounding system to protect large areas from damage by the discharge directly depends on the height of the pin. The area that a pin lightning rod can protect is defined as a circle with a radius identical to the height of the rod.
Cable protection
If there is a roof covered with slate, the lightning discharge receiver is made in the form of a metal cable. The latter is stretched along the roof ridge. The height of its location should be at least 0.5 meters from the surface.
If it is necessary to create the most reliable protection, metal supports are used to tension the cable, which are isolated from the discharge receiver. This method is also applicable for buildings with wooden roofs and ceramic tile roofs.
Mesh protection
This solution is the most difficult to implement. Typically used for tiled roofs. The discharge receiver in this case is a wire mesh laid on the roof of the building. The cross-section of the electrical conductors in this case should be at least 6 mm, and the cell pitch should be about 6 x 6 m.
The considered system is connected to the down conductor and the grounding element by welding. If this is not possible, the use of bolted fasteners is allowed.
The installation of down conductors here is carried out using round steel wire. They are laid towards the ground along the walls and roof of the building, fixing the electrical conductors with special brackets.
The route for placing down conductor elements is selected in such a way that current-conducting elements do not come into contact with doors, windows, porches, metal garage doors, and other structures with which people may interact during the operation of the facility.
If the building contains in its structure an abundance of flammable materials (expanded polystyrene, wood, plastic), the down conductor conductors should be laid at a distance of about 15-20 cm from surfaces. This approach to arranging a lightning protection system will help avoid fires during strong, prolonged thunderstorms.
In this case, an internal lightning protection system can also be installed, which involves the installation of special arresters capable of protecting electrical equipment from surge voltages. Such means are placed in close proximity to the point at which the power cable enters the facility.
Down conductor
It is a mandatory element of lightning protection systems. Designed to transfer charge to the ground loop.
The current conductor is a metal wire with a thickness of at least 6 mm, which is connected to the discharge receiver. The combination of both elements allows you to absorb loads up to 200,000 Amperes. The most important condition for combining these structural components is the performance of highly reliable welding, which eliminates the possibility of rupture of connections and weakening of fastenings under the influence of wind or falling snow layers.
The down conductor is lowered along the walls of the object from the roof, securing the conductor with brackets. The end of the metal wire is directed to the ground loop. If the system involves the installation of several charge-conducting elements, they are placed at a distance of about 20-25 meters from each other at the maximum possible distance from doors and windows.
According to safety regulations, it is forbidden to bend down conductors sharply. Making such miscalculations increases the likelihood of a spark discharge in the event of an object being struck by lightning. This, in turn, can lead to the structure catching fire.
When installing a lightning protection system, it is advisable to make the down conductor as short as possible. At the same time, it is recommended to install it closer to sharp protrusions, edges of gables,
Grounding
Designed to ensure effective discharge discharge to the ground. It consists of several interconnected electrodes driven into the ground.
When putting a facility into operation, according to the rules, a common grounding must initially be provided for all electrical appliances connected to the network. If it is not there, preparing the element is not so difficult. To do this, take a steel or copper conductor with a cross section of 50-80 mm. A trench is dug 3 m long and at least 0.8 m deep. Rods are driven into the opposite sides of the recess and connected using a steel crossbar by welding. A down conductor is attached to the resulting structure. Finally, the welding elbows are painted, after which the grounding structure is driven to the bottom of the trench.
Checking lightning protection systems
Testing the discharge discharge system involves a visual inspection of structural elements, as well as measuring resistance indicators. Externally, the reliability of the connection of contacts between the lightning rod, down conductors and grounding is checked. All welding points are tapped with a hammer.
Carrying out measurements of resistance indicators of grounding conductors of individual lightning rods requires the presence of special equipment registered in accordance with regulations.
As a result
As you can see, there are several options for lightning protection of an object. Certain solutions are selected depending on the breadth of the budget, the nature of the structure, and the need to ensure a certain level of security.
Currently, the development of power supply projects when putting a facility into operation does not provide for the creation of lightning protection. At the very least, its presence is not a mandatory requirement. Therefore, the decision on the advisability of installing a system to protect a building from lightning damage is made by each owner based on personal considerations.
The mechanism of a lightning discharge has been sufficiently studied, but nature often presents surprises and in some cases even professionals find themselves at a dead end. An effective lightning protection system includes external and internal lightning protection. The first protects against a direct lightning strike to a house, building or any object (satellite dish, monument, fuel tank, etc.). At the same time, experts have long been familiar with the possible spread of lightning current through underground and above-ground communications such as pipelines and communication networks. They have learned to reliably protect people and their property from direct lightning damage. In accordance with current domestic regulations, categories of protection against direct lightning strikes are determined and lightning protection calculations are performed.
The phrase internal lightning protection is not entirely clear to many. Lightning cannot penetrate into a building through window glass, ventilation or a chimney, so many do not understand why it is necessary to create internal protection and what can be considered effective internal lightning protection. Thanks to efficient external lightning protection, the electric discharge is caught by a lightning rod and sent through down conductors through special grounding connections for dissipation in the ground. However, the entire set of these measures and devices does not protect against the electromagnetic field that arises during this process. It can easily penetrate deep into a building and cause failure of consumer electronics, as well as complex microprocessor units. An electromagnetic field can damage the operation of automation and cause false or incorrect commands in control systems. The internal lightning protection system allows you to reliably protect all sensitive electronic equipment located inside the building.
Internal lightning protection: vital safety
Experienced specialists consider the division of lightning protection into external and internal to be arbitrary. The strength of the negative influence of the electromagnetic field inside the house directly depends on the path of lightning propagation and the paths of current flow. A clear example of this is a non-fictional real-life example. Foreign architects in our country designed and built an interesting building as tall as a television tower. The architects used a thin spire installed vertically as an elegant decoration for the outline of the building. The base of the spire was at ground level, and the top exceeded the roof by 50 m. This decision of the architects did not cause negative feedback from the electricians, but on the contrary, they liked it.
Statistics say that in the central European part of Russia, lightning strikes 350-meter buildings on average 10-15 times per thunderstorm season. According to observations, only two of them have a standard discharge mechanism, that is, they are formed in a thundercloud and tend down to the ground through a plasma channel. All the remaining ones are formed at the top point of the building itself and rush from it upward to the thundercloud. This phenomenon is called "rising lightning." Due to the fact that the place where lightning originates and starts is at the top of the structure, it is easy to intercept. It would seem that the lightning rod is not needed; its functions were replaced by the spire.
The problem was identified after a detailed analysis and analysis of the current situation. The spire was located at the rear wall of the structure. Due to the strongly expressed asymmetrical geometry of the building, it turned out that the lightning discharge was directed in a concentrated stream towards the ground along the rear wall. At the same time, he created a magnetic field of enormous strength, which was not compensated for by anything. The powerful electromagnetic field created a great danger for the internal electrical network of the building. Therefore, designers had to create a complex system of external lightning protection, which would reduce the value of the total electromagnetic field. All their efforts still did not help to completely protect the electrical equipment in this building and professionals had to design and install internal lightning protection elements.
A second striking example of the importance of competent organization of internal protection is a tank with liquid fuel, which is located in the open air. This object is designed in such a way that it is not afraid of a direct lightning discharge. However, even here, serious fires are often recorded during a thunderstorm. Severe accidents occur due to ignition of flammable gaseous emissions above the breathing valve of the tank. This occurs when an imperfect flame blocking system allows the flame to pass into the tank. Especially for these cases, these facilities are equipped with automatic fire alarms and fire extinguishing systems. During accidents, the electromagnetic field created by lightning current is the cause of failure of these systems and the root cause of serious accidents.
Surge protection devices
Even well-executed measures for designing protection from the negative effects of lightning discharge and correct calculation of lightning protection do not allow 100% protection of internal electrical circuits from the destructive effects of the electromagnetic field. The main element of internal protection are devices that prevent surge voltages (SPDs) and special metal screens. The main function of an SPD is to block the spread of high potentials on the way to the connected electrical equipment. Due to the huge variety of electrical devices that need protection, leading SPD manufacturers offer a wide variety of configurations for these devices. For these products, they are forced to allocate separate large-format volumes and it can be quite difficult to purchase lightning protection components for them without detailed consultation.
SPDs are necessary to prevent overvoltage from penetrating electrical circuits to household appliances. Their mechanism of action is to quickly interrupt the electric arc of the accompanying current, and this is in some cases very difficult. The requirements for these protective devices are quite stringent. Some products must perform their functions flawlessly and with high reliability, despite their miniature dimensions and the huge number of protected microcircuits. Not only the safety and stable functioning of the facility, but also the lives of many hundreds and thousands of people often depend on this.
Most of the world's manufacturers of SPDs for lightning protection have special research and testing laboratories that are looking for ways to solve the problem of reliability of the smallest SPDs. Test complexes simulate all possible negative impacts of a lightning discharge on protective devices. In addition, specialists from these departments resolve issues of SPD compatibility with high-frequency units (information transmission channels, enterprise television security systems, etc.). Therefore, thick catalogs of manufacturers are rather the key to the successful implementation of the most complex lightning protection project. After all, they definitely guarantee that it will be easy to buy the necessary lightning protection components.
Cost calculation
Our objects
Representatives of construction organizations and homeowners are always faced with the question of what lightning protection is, what it consists of, what it is, how to choose the best option, whether it is mandatory or not, and who to consult on this matter. Despite the actual technical complexity of the issue, we will still try to figure it out.
Lightning protection is a set of technical measures, including the stages of design, installation and maintenance, aimed at protecting an object both from direct lightning strikes and from associated adverse electrical phenomena.
What is the danger?
During a thunderstorm, all buildings, especially if they are taller than surrounding structures, can potentially be struck by lightning. The power of this natural phenomenon is such that it melts sand, but if it gets into a construction site it is fraught with significant destruction and fire.
But, in addition to this, a thunderstorm atmosphere also carries another danger - electrified air can provoke strong electromagnetic pulses, causing surge voltage in the electrical network. For modern apartment, office and industrial buildings and private homes filled with all kinds of electronics, this means inevitable failures, short circuits, equipment breakdowns and fires that can go beyond local ones.
Thus, the threat is absolutely real and security measures are extremely relevant for each structure.
How to protect yourself?
Fortunately, progress does not stand still. Modern engineering offers a whole range of protective measures, collectively called lightning protection or lightning protection.
Technically this includes:
- External lightning protection system
- Internal lightning protection system
protects against direct discharge. It consists of an air-termination mast that receives the main strike, a down conductor and grounding that ensure discharge of the discharge into the ground. The type of system can be passive (traditional lightning rod) or active (intercepting lightning due to ionization of the air around the lightning rod);
protects networks and electrical equipment from secondary phenomena. Consists of surge protection devices and potential equalization system
Lightning protection measures include:
Design
To carry out all protective measures correctly, it is extremely important to make a high-quality project that will take into account not only the characteristics of a particular building, but will also meet all regulatory documents. The best option is when the design of lightning protection is carried out at the time of the overall design of the building, because in this case, it is possible to use the internal elements of the structure as components of a lightning protection system, which will reduce its cost. Today, when designing, the zone concept of lightning protection is increasingly used, the basic principles of which can be found.
The MZK-Electro company will quickly and efficiently draw up a design for a lightning protection system or its individual elements based on equipment from world-famous manufacturers.
Installation
Usually, if you have a clear project, the necessary equipment and experienced specialists, it takes from 1 to 3 days, depending on the complexity and volume of work. You can install the system at any time of the year, but it is advisable to prepare for the thunderstorm season in advance.
Service
Any complex technical devices have their own preventive maintenance regulations, and the lightning protection system is no exception. For uninterrupted operation, periodic inspection and testing of systems is required. In the event of a breakdown, the help of professionals is irreplaceable, because... Identifying causes and eliminating them requires qualifications and skills.
The whole range of events can be ordered from the MZK-Electro company. With us you will receive comprehensive advice on all lightning protection issues and qualified service. Each specialist of our company is distinguished by deep knowledge and many years of experience, all equipment and work are certified - all this allows us to guarantee results.