建筑电气英文论文.doc

Intelligent building lightning protection, earthing, anti-interference【Pick to】picked this paper in view of the defects of traditional lightning protection system, and the way of intelligent buildings, intelligent building should establish the overall lightning protection system was put forward, which include external lightning protection and lightning protection technology.Introduce the specific lightning protection system protection methods.Including power supply, UPS power supply system, terminal power supply, communication network system, telephone lines and special line, LAN lines, satellite receiving day finally reveals the feeder protection and earthing protection system in the development of several new technology of lightning protection of intelligent buildings.【 key words 】 intelligent building； lightning protection ；grounding shield bonding Before, today the development of human science and technology has entered the stage of the development of highly informationization, it has brought mankind unprecedented convenient and quick, is one of the most prominent performance in the area of construction in recent years a large number of the construction of intelligent buildings.Intelligent Building (Intell ig ent Building) is developing rapidly in China, has become a new growth point of national economy.Intelligent building is by building Automation BA (BuildingAutomation), Communication since moving CA (Communication Automation), office Automation OA (Of f ice Automation) on the basis Of integrated wiring, through the system integration technology, constitute an integrated management system.Intelligent building for senior or more commonly tall building, including all kinds of electronic equipment, computer and network systems, such as density, high integration, and thus the danger of lightning electromagnetic pulse attacks it also greatly increased, the consequences could make the whole building the system of equipment damage, loss of data and operation error, even paralysis, cause huge economic loss, so how to effectively avoid the damaging effects of lightning is an important subject in the design of intelligent building.Especially the rapid development of electronic technology, all kinds of advanced measurement and control, telecommunications and computers is increasingly widely used in electronic products, Especially the development of computer technology and communication technology combination, integration of electronic apparatus and very large scale integration and the development of new network communication technology for the development of the information age has played a great role in promoting and pushing;But on the other hand, there is a widespread low insulation strength the microelectronic devices, poor overvoltage tolerance of Achilles heel, once the lightning strike, the impact of the surge overvoltage, light led to the suspension of the operations of the electronic system, equipment permanent damage, or interruption of other relevant systems, has been paralyzed caused immeasurable directly and indirectly the huge economic loss and far-reaching influence, for the financial, securities, health care, insurance, aviation, aerospace, defense, and other countries especially important organs, the degree of violation and lightning has more to more serious, the number is becoming more and more frequent.For this, I think for lightning protection, is not only necessary, but is must implement.Second, the defects of traditional lightning protection system1, conventional lightning rod. The principle of lightning rod is thundercloud discharge is close to the ground, the ground electric field distortion, at the top of the lightning rod, the formation of local electric field concentrated space, influence the direction of the discharge, due to lightning is calcuated guide lightning to the needle to put, again through the downlead, grounding device will attract the earth, and the lightning current to protect objects.In principle, the lightning rod is actually lead thunder needle, add one regional lightning probability, have the effect of fire.2, the calculation of protection range of lightning rod protection around the world vary, cable method, calculation methods of curve method, improvement of line method, etc.The above calculation method, have one thing in common, is the needle, the more protection range is wide.BG 50057-9 4 gb adopt IEC recommended ball : refers to a certain radius of sphere, on top of a building with connect ShanQi rolled and rolled the ball by building on the ShanQi hold up, then the spheres arc and the range of between buildings.Long-term practice prove that this is not completely in line with economic theory and practice.Such as high-rise buildings, even if the top mount the lightning rod, but below the top floor will also meet sideswipe rays attack.The secondary effect of 3, when lightning rods, the lightning rod, lightning attack buildings by downlead will attract the earth, and the lightning current due to the existence of earth resistance, lightning charge cant fast all negative charge neutralization, the earth will inevitably cause local potential rise, causing high induced over-voltage, step and touch voltages and counter and a series of secondary effects.Ac power distribution, and wanted to introduce this kind of high voltage dc machine room, UPS output, the input end is punctured, minicomputer and other network equipment connection is punctured.This counter voltage little number of kv, many tens of thousands of volts, burn out directly with the insulation of the electrical parts, for personal and microelectronic devices caused great threat., therefore, the defect of traditional lightning protection, cannot satisfy the requirement of the intelligent building and its microelectronics equipment lightning protection, it is necessary to adopt a more advanced lightning protection equipment and to provide more effective from the perspective of building the overall lightning protection lightning protection.Three, intelligent building by way of lightningIntelligent building to suffer lightning shock ways mainly have three kinds:(1) direct lightning, lightning hit directly damaged equipment outdoor equipment, intelligent buildings or lightning hit directly overhead cables, cable fusing equipment damage phenomenon, called the lightning strike.(2) the lightning induction, electromagnetic induction and static electric induction is called induction lightning, also known as secondary ray.The damage to the equipment its not as heavy as direct lightning, but it is much larger than the direct lightning probability of occurrence.(3) ray waves of shooting: intelligent control system of power cable, signal transmission lines or in control room of the metal line when you meet the lightning or thunder and lightning induction thunder electric wave along these metal wire of shooting in the equipment, potential difference makes equipment damage phenomenon, called the thunder electric wave of shooting.Ray waves of shooting will indirectly by cable transmission to the intelligent building systems and equipment, indirect cause equipment damage.Therefore, we should according to the different role of lightning way considering the lightning protection system of intelligent building as a whole.Fourth, overall lightning protection system of intelligent building1, intelligent building lightning protection necessityConventional lightning protection system using the lightning rod, roof ShanQi, ferrari brother cage based grounding network in lightning protection and grounding, although can protect of intelligent building and its personnel, but for the lightning induction, electromagnetic pulse, surge circuit caused by electronic interference, such as the traditional lightning protection systemHas the following several aspects of the flaw: (1) the lightning hit directly outside the extension in intelligent buildings, power supply and communication cable lightning induced current can be shooting to the building rapidly.(2) large cities switch of the power grid and large power users of start-stop surge.(3) intelligent building electrical equipment (such as air conditioning host, elevator, high-power pump, etc.) as a result of the frequent start-stop surge.(4) power supplies, telecommunications and data lines connected to other buildings or being struck by lightning on the ground and the transmission or induction of electromagnetic pulse and surge current.(5) electrostatic through data line the damage to the equipment ammeter components directly.J through the above analysis of the intelligent building lightning protection technology is increasingly important, and it requires a more comprehensive lightning protection technology.Because cables are gathering in intelligent buildings, equipment, various, complex microelectronic systems, thin and protective ability, in order to ensure the normal running of the system, safety equipment, and special measures must be taken to protect, so the lightning protection of the intelligent building is a rigorous system engineering.So intelligent building lightning protection besides considering direct lightning protection measures of building itself, also must attach great importance to ray, also must attach great importance to the lightning electromagnetic compatibility, strengthen and perfect the lightning protection measures of building electronic equipment.IEC on technical file will be defined respectively as external lightning protection system and internal lightning protection system, taking their interface Shared grounding body, shielding, equalizing, bonding technology processing methods, such as, to combine the two effective, forming a relatively independent and unified whole lightning protection system.2, external lightning protection systemThe external lightning protection of intelligent buildings is mainly refers to prevent lightning strike and prevent side stroke, its role is to protect the building itself is not lightning strike.So you must have good common grounding system and the discharge channel.(1) the good common grounding system and the discharge channelA common base earthing body, shall establish a comprehensive common grounding system in intelligent building.Because of various ac and dc equipment is numerous, the intelligent building line, building communication work, security should be protected area, grounding of dc workplace and architecture as a good bar connection, form a complete common grounding system.Avoid potential difference between the grounding line, in order to eliminate the phenomenon of induced overpotential counterattack, ensure the normal operation of electronic equipment.B, sufficient discharge channel and equalizing measuresBuilding of rebar in reinforced concrete is used as the lightning protection downlead, increasing its shunt branch from the roof, reduce the number of lightning current on the conductor, and building profile each corner column rebar should be used.Because mostly for high-rise buildings, intelligent buildings also flanking the thunder prevention measures should be taken, in more than 30 m outside of the building shall be ring beam rebar welding formed equalizing ring connection, and connected to the lightning protection downlead.Make full use of the structure of the pile foundation reinforcement, column reinforcement, the ring beam, roof floor reinforcement, make them reliable welding, the formation of a good lightning current discharge path.3, internal control systemInternal lightning protection including the lightning protection electric induction, the counter, and lightning protection waves of shooting.Good internal lightning protection can reduce building of lightning current and electromagnetic effect, and can prevent the counter-attack, step and touch voltages and other secondary ray hurt and harm caused by the electromagnetic pulse.The internal lightning protection mainly adopt measures to shield, equipotential connection, etc.(I) the reasonable shieldingIn intelligent building, electromagnetic compatibility measures is very important, in order to avoid the dysfunction of equipment used, to avoid the equipment damage, even a wiring system equipment should be able to prevent internal guide their conduction disturbance and outside interference.These interference produced have a plenty of because the coupling phenomenon between the wires, have a plenty of because of the effect of capacitance or inductance effect.Its main source is ultra high voltage, high power radiated electromagnetic fields, the lightning discharge.These phenomena will be used to send or receive a high transmission efficiency of equipment produce very big interference.So on the equipment and its wiring protection measures must be taken, from interference from various aspects.Shielding and its correct grounding method is the best protection to prevent electromagnetic interference.Equipotential connection: intelligent building in order to ensure produce counter and dangerous step and touch voltages, should enable building floor, wall, and metal pipe, line is in with potential, this should be in the position of each layer of reinforced concrete building embedded with building structure within the equipotential connection to the lightning conductor plate, so that are connected to the earthing trunk.Intelligent building of the equipotential connection including total equipotential connection and local equipotential connection.Five, the new technology of intelligent building lightning protection1, a new generation of unconventional lightning rod technology: with building intelligent level of ascension, lightning protection technology, also Good attention, a kind of gradually into the mainstream of unconventional lightning rod in advance to discharge.Lightning rod, it solves the traditional passive flash, secondary lightning effect of serious limitations, received more and more widely used in our country.A new generation of lightning rod no source, no radiation, the energy from lightning before the potential difference between the ground and clouds.It happened in lightning critical point in advance produce an up the forerunner, the formation of a lightning preferred path, overcome the deficiency of the traditional lightning rod passive joint flash, greatly improve the lightning protection scope.2, new network lightning protection device: intelligent building network of electronic devices with a very large scale integrated circuit, its itself easily burned in high voltage, high current situation.So early of lightning rod, lighting protection and power supply prevents thunder can no longer be optimalShould demand.In lightning generates a strong electric field, which leads to the potential of this area is much greater than other areas, and as good conduc