Why should lightning protection facilities carry out annual inspection

With the occurrence of early thunder in most parts of Jiangnan, all regions have entered the season of frequent thunderstorms. In recent years, lightning disasters have become one of the more serious natural disasters. Therefore, the performance of lightning protection devices is directly related to the safety of lightning protection.
When it comes to lightning protection devices, people naturally think of lightning rods. In fact, from the perspective of lightning protection technology, modern lightning protection facilities include external lightning protection (direct lightning protection for buildings or facilities) and internal lightning protection (lightning electromagnetic pulse protection). The external lightning protection system is mainly In order to protect the building itself from fire accidents and personal safety accidents caused by direct lightning strikes; the internal lightning protection system is to prevent damage caused by lightning wave intrusion, lightning induced overvoltage, and system operation overvoltage intrusion.
The external lightning protection device, also known as direct lightning protection technology, mainly consists of lightning rods, lightning protection belts, lightning protection nets, and lightning protection cables, among which lightning rods are the most common direct lightning protection devices. When the thundercloud discharge is close to the ground, it distorts the ground electric field. At the top of the lightning rod, a space where local electric field strength is concentrated is formed to affect the development direction of the lightning pilot discharge, and the lightning is guided to discharge to the lightning rod. The device introduces lightning current to the ground, thereby protecting the protected object from lightning strikes.
Is it okay as long as the lightning protection device is installed?
First of all, let's take a look at the composition of the lightning rod. The lightning rod is mainly composed of three parts: a lightning receptor, a down conductor, and a grounding device. The three should be well connected, and the grounding resistance meets the requirements of the specification to achieve the role of lightning protection. Although the lightning rod is labeled as "lightning protection", it only means that it can protect the protected object from lightning damage. On the contrary, it is the upper body of "lightning", which is exposed to thunderstorms for years. Its performance is naturally "tested". Coupled with the test of severe cold and heat such as wind, sun, rain, frost, and rust and rot all the year round, it often leads to the occurrence of breakage, corrosion, severe rust, poor contact, and even the breakage between the three parts. Lightning devices not only do not protect against lightning, they may also become lightning devices, but instead increase the potential danger of lightning hazards.
Secondly, in the process of building maintenance, renovation, decoration, etc., some units and construction personnel do not pay attention to the protection of their lightning protection belts (nets), causing man-made damage, and some of them accidentally dig out the grounding device during construction, which leads to Line breakage, etc., will bring hidden dangers to lightning protection.
In addition, some units have indifferent lightning protection awareness and do not understand the performance of lightning protection devices. They are randomly pulled and connected to other electrical circuits, such as telephone lines, broadcast lines, TV receiving antennas, and overhead low-voltage lines. These electrical circuits often become the "culprit" of various electrical equipment in buildings subjected to induced lightning strikes. These natural and man-made damages have caused huge hidden dangers to lightning protection devices. Once they are struck by lightning, the consequences are unbearable.
In addition, the lightning protection measures inside the building are mainly used for lightning protection devices for various electronic and electrical equipment to prevent induction of lightning. Because the materials used are mainly zinc oxide varistor components and other electronic components, these lightning protection devices are suffering from After one or more repeated induction lightning strikes, its performance is significantly reduced or deteriorated and attenuated, so periodic inspections must also be carried out to find problems through detection in order to repair or replace in time. According to the annual inspection (spot check) data of the author's unit, the passing rate of lightning protection device detection is only about 80%.
Therefore, in some flammable and explosive places such as petroleum and chemical industry; densely populated public places such as financial institutions, computer systems of enterprises and schools, and schools, while doing daily maintenance and inspection of the lightning protection devices of the unit, qualified persons can be employed Professional institutions with testing qualifications regularly conduct performance safety tests to ensure their normal performance and prevent unburnt.

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July. 06, 2020