Lightning protection lightning rod lightning protection analysis and improvement suggestions for airport station
Summary: Using the broken line method and the rolling ball method to analyze the lightning protection of the lightning rods of the two types of airport stations The existing deficiencies of the lightning protection of the lightning rods of the high pole lights are based on the "rolling ball method" recommended by the IEC, and the protection radius of the two types of high pole lightning rods is calculated and analyzed, and the length of the lightning rod required for retrospective analysis is analyzed. Suggested improvements are proposed.
Keywords: Pingteng pole lights at airport station; lightning protection analysis; rolling ball method; folding line method
1 Introduction: Guangzhou Baiyun Airport is located in a thunderstorm-prone area, airport station flat The pole pole body is 25m high from the ground. It is inevitable that the isolated towering high pole light will be struck by lightning during the thunderstorm season, so there is a lightning high light on the station. Risks threaten the safety of past aircraft and personnel. It has been nearly seven years since the airport station's high pole lights have been in use, and in the past operations, high pole lights were hit by lightning. In the North District freight station, the high pole light of the station has been damaged by lightning strikes. Serious lightning strikes and damage to high-light-light facilities are rare, but the airport has high requirements for safe operation of high-pole lights. It is particularly important to analyze and explore measures to improve the lightning protection capability of existing high-light lightning rods. Important practical significance. Starting from the characteristics of the high pole light of the airport station, this paper simplifies the outer dimensions of the high pole light panel that needs to be protected by the lightning rod, and uses the relevant lightning protection theory to analyze and propose corresponding improvement measures.
2 Theoretical basis for analysis
2.1 Polyline method
If the height of the protected object is hx, then the protection at the hx level p>
Radius rx is calculated according to the following formula [1] :
2.2 Rolling ball method
China's past lightning protection design specifications (such as GBJ57-1983) or overvoltage protection design specifications (such as GBJ64-1983), lightning rods and lightning protection lines
>The scope of protection is determined according to the "folding method", and the current national standard GB50057-1994 "Building Lightning Protection Design Code" stipulates the "rolling ball method" recommended by IEC
"To determine [2].
The so-called "roll-ball method" is to select a sphere with a radius of hr (ball radius), rolling along the part that needs to protect the direct lightning strike, if the sphere only touches the lightning rod ( The line) or the lightning rod (wire) and the ground, without touching the part to be protected, is within the protection range of the lightning rod (wire). The radius of the ball h r takes different values depending on the lightning protection category of the building.
force Barracks, arsenals and other explosions caused by electric sparks, causing great damage and buildings of personal injuries are the first type of lightning protection buildings; national computing centers, state-level halls, office buildings, large-scale exhibitions and exhibitions Buildings, large railway stations and other particularly important buildings belong to the second type of lightning protection buildings; isolated tower buildings such as water towers and high pole lights are the third type of lightning protection buildings. Therefore, in this analysis, the radius of the ball is taken from the radius of the ball of the third type of lightning protection building, that is, h r = 60 m.
Figure 3 is a schematic diagram of the protection range of a single lightning rod in the rolling ball method:
3 The type of lamp panel and its characteristics of the station high pole lamp: There are two types of lamp panel for the high pole lamp at the airport station. The species is a hexagonal light panel and the other is a trapezoidal light panel.
3.1 Hexagonal light panel
The hexagonal light panel is characterized by the luminaire above the lamp panel. The highest point of the luminaire is basically the same as the top of the pole, and the high pole luminaire The maximum horizontal distance between the top and the lightning rod is about 1.77m.
3.2 Trapezoidal high pole light panel
The main feature of the trapezoidal high pole light panel is that the fixture is mounted under the high pole light panel, the top of the ballast box on the lamp panel Basically the same as the top of the high pole light (2) Rolling ball method to analyze the protection range of the hexagonal high pole light panel lightning rod.
Some hexagonal light plate lightning rods have a protection radius of 1.65m. The maximum horizontal distance between the existing lamp and the lightning rod is 1.77m
(177cm), 1.65<1.77. it="" can="" be="" seen="" that="" the="" protection="" radius="" of="" the="" existing="" lightning="" rod="" is="" slightly="" different="" from="" the="" maximum="" horizontal="" distance="" of="" the="" protected="" object.="">
(3) Analysis of the protection range of the trapezoidal high pole lamp panel lightning rod by the fold line method.
Hx=25m is known, h=hx +L=25+1.612=26.612m, ie h≤30m, substituting into formula 1 to get: R=hh x =1.612m
That is, the protection radius of the existing trapezoidal high pole light panel lightning rod is 1.612m. The maximum horizontal distance between the existing luminaire and the lightning rod is 2.49m (249cm), 1.612<2.49. it="" can="" be="" seen="" that="" the="" protection="" radius="" of="" the="" existing="" lightning="" rod="" has="" a="" large="" gap="" from="" the="" maximum="" horizontal="" distance="" of="" the="" protected="" object,="" and="" the="" lightning="" rod="" is="" not="" well="" protected.="" lamps="" on="" the="" lamp="" panel.="">
(4) Rolling ball method to analyze the protection range of the trapezoidal high pole light panel lightning rod.
The protection radius of the existing trapezoidal high pole light panel lightning rod is 1.12m. The maximum horizontal distance between the existing luminaire and the lightning rod is 2.49m (249cm), 1.12<2.49. it="" can="" be="" seen="" that="" the="" protection="" radius="" of="" the="" existing="" lightning="" rod="" has="" a="" large="" gap="" from="" the="" maximum="" horizontal="" distance="" of="" the="" protected="" object,="" and="" the="" lightning="" rod="" is="" not="" well="" protected.="" lamps="" on="" the="" lamp="" panel.="">
4.2 Improved Analysis of Lightning Rods Recommendations
4.2.1 Improved Analysis of Lightning Rods for Hexagonal High Rod Lights
To effectively protect high pole light panels For the electrical equipment and components, the protection radius of the existing hexagonal high pole lightning rod should be greater than or equal to 177cm, ie R1.77m. If the required lightning rod length is L x , then substitute 2 can be obtained: Lx2- 70L x +175.25=0→L x ≈2.6m means that the length of the lightning rod on the top of the high pole pole body needs to reach 2.6m to effectively protect the electrical equipment and components on the lamp panel. Therefore, it is recommended that the lightning rod of this type of high pole lamp be used. Properly extend the improvement so that the lightning rod is 2.6 meters long. 4.2.2 Improved Analysis of Trapezoidal High Rod Lightning Lightning Needle To effectively protect the electrical equipment and components on the high pole light panel, the protection radius of the existing trapezoidal high pole light lightning rod should be greater than or equal to 249cm, ie R≥2.49m. If the required lightning rod length is L x , then the replacement type 2 can obtain Lx2-70L x +248.4884=0→Lx ≈3.75m, that is, the length of the lightning rod on the top of the high pole pole body should reach 3.75m to effectively protect the lamp panel. Electrical equipment and components, it is recommended to properly extend the lightning rod of this type of high pole lamp, so that the length of the lightning rod is 3.75m.
5 Concluding remarks
This paper uses the folding line method and the rolling ball method to analyze the lightning protection of the lightning rods of the high-level pole lights of the two types of airport stations, and find out the lightning protection needles of the existing high pole lights. The shortcomings of Ray's existence, and based on the "rolling ball method" recommended by IEC, calculate and analyze the protection radius of the two types of high pole lightning rods. It can be seen from the analysis that the existing trapezoidal high pole lightning rod protection radius has a large gap from the maximum horizontal distance of the protected object, and the lightning rod can not protect the lamp on the lamp panel well, and the lightning rod needs further improvement. After further improvement analysis, it can be seen that the length of the trapezoidal high pole lightning rod needs to reach 3.75m to better protect the equipment and components on the lamp panel. In addition, the length of the lightning rod in this paper is measured by the proportional method, and there will be a certain error with the actual size, so there will be some error in the calculation and analysis results.
