Main hazards of lightning
According to the hazard characteristics of lightning, its destructive effect is mainly caused by lightning current. Usually lightning occurs in three forms, namely, direct lightning strike, induced lightning strike and lightning wave. Generally speaking, lightning strikes are caused by direct lightning strikes. Because the current it instantly releases is quite large, the resulting high temperature and high pressure cause explosion, fire and building collapse, resulting in human and animal casualties. 1On June 30th, 998, a farmer in a residential area in Nanjing was killed by lightning; The next day, two people were killed and seven injured in a lightning accident at Dafeng Beach in Jiangsu Province. On July 10, more than 50 farmers in Yungui Township, a county in Guizhou Province were struck by lightning while taking shelter from the rain, resulting in the tragedy that 14 people died on the spot and 42 people were injured. These lightning accidents are all caused by direct lightning.
The main harm of induced lightning is that the current forms a lightning shock wave along metal wires or conductors, which enters buildings, causing damage to users' instruments, equipment or household appliances, and under certain conditions, it will also cause major lightning accidents such as casualties and fires. 90% lightning accidents are caused by induced lightning. For example, the fire of Huangdao oil depot in Shandong province, which shocked China and foreign countries ten years ago, was caused by induction lightning. With the rapid development of modern high technology, it is the main target of lightning induction in the fields of electronic equipment, power supply equipment, communication broadcasting, computer network information transmission and so on.
Lightning wave is an impulse voltage generated by lightning stroke on overhead lines or overhead metal pipelines, which propagates rapidly along the lines or on both sides of the pipelines at a speed of 300m/us (150m/us for cables). If it intrudes into the building, the insulation layers of power distribution devices and electrical lines may be broken down to produce short circuits, or inflammable and explosive articles in the building may burn and explode. 1in may, 994, nearly 100 microcomputers of a daily newspaper in Guangzhou were damaged by lightning because of the invasion of lightning waves.
In addition to irresistible natural phenomena, people's lack of knowledge and awareness of lightning protection is the main reason for frequent lightning accidents. Some people think that lightning rod is a panacea. With it, it will be safe and sound. Some units are unwilling to spend this money on lightning protection projects. Even though some units have installed lightning protection facilities, their placement is not standardized or they have not been maintained for a long time, which has become the bane of attracting lightning. During the thunderstorm, field work and walking cannot leave the highest point of the environment in time; Some people even run under trees and eaves to hide from the rain, and indoor personnel even open doors and windows to watch the rain or watch TV and make phone calls, and fail to unplug household appliances in time, resulting in frequent tragedies of lightning strikes and electric shock casualties.
Measures to prevent lightning accidents
In order to avoid or reduce the occurrence of lightning accidents and ensure the safety of people, livestock and buildings, for buildings, architectural design should be taken as the first step, and lightning protection facilities should be comprehensively considered according to the functions of buildings, especially neon lights, billboards, metal flagpoles, microwave towers, shared antennas attached to outdoor cleaning and other potential unsafe factors. Secondly, we should do a good job in the quality inspection, supervision and completion of construction, and check and accept the lightning protection facilities of buildings in strict accordance with the standards stipulated by the state. Ordinary antennas, main power supply of residential buildings, computer network users and overhead telephone lines should be equipped with special lightning arresters, and the safety performance of these lightning arresters should be tested and maintained before the thunderstorm season every year.
For individuals and families, first of all, we should know more about lightning protection knowledge, enhance the awareness of lightning protection, and actively take preventive measures to avoid lightning damage. Secondly, we should publicize and educate people around us with our own knowledge of lightning protection; During the thunderstorm, when walking outdoors, try to leave the highest point of the environment, run to a low-lying place or simply get down. Don't shelter from the rain under trees, telephone poles, overhead towers, chimneys and tall buildings, and don't use metal umbrellas. Indoor personnel should close doors and windows, don't touch metal wires, don't make phone calls or watch TV, disconnect the signal transmission line of closed-circuit TV, and unplug all kinds of household appliances. It is best to stop using the home computer and cut off the power supply in thunderstorm weather. If you need to work in thunderstorm weather, lightning protection measures must be taken to prevent the attack of induction lightning.
For more information about project/service/procurement bidding, and to improve the winning rate, please click on the bottom of official website Customer Service for free consultation:/#/? source=bdzd