On the application of electrical detection technol

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Talking about the application of electrical detection technology in fire protection work

electric energy is an indispensable energy in people's production and life, and all kinds of electrical equipment are widely used in daily production and life. They are the foundation of modern civilization and one of the important symbols to measure the degree of modernization of a country. However, if the electrical equipment is used, managed, operated and maintained improperly, resulting in the uncontrolled accidental release of electric energy, it will bring disaster to people. According to the basic characteristics of electrical fire or electrical accidents, effective electrical detection is an important method to prevent and reduce electrical fire accidents

    1. Talking about the feasibility of electrical detection in preventing and reducing electrical fire from the cause of electrical fire

1.1 the mechanism and necessary conditions of electrical fire

the occurrence of electrical fire accidents must have three conditions of combustion

(1) electrical fire source: mainly refers to hot spots, electrical sparks and arcs in relevant parts of electrical equipment and lines

(2) combustibles: insulating materials of electrical devices, buildings and structures, decorative materials and combustibles around other electrical devices

(3) combustion supporting material: oxygen in the air

mechanism: the interaction of the three may lead to electrical fire

1.2 cause analysis of electrical fire

electrical fire is caused by electric energy. The base ring of cellulose macromolecule is D-glucose β (1) occurred. The direct causes are mainly electric leakage, short circuit, overload, poor contact, overload, arc, electric fire, which are divided into impact test piece notch manual broaching machine, impact test piece notch hydraulic machine broaching machine, impact test piece notch electric broaching machine and other impact test piece notch projector flowers, causing high temperature heating and igniting surrounding combustibles to cause a fire

(1) leakage: the insulation capacity of the wire or its support material is poor, so that there is a small amount of current between the wires or between the wires and the earth, and the leakage spark can become the ignition source of the fire

(2) short circuit: on the electrical circuit, due to various reasons, two points with different potentials are connected or collided, resulting in a sudden increase in current. Due to the large current in the short-circuit circuit circuit, it is very easy to produce strong electric sparks and arcs at the short-circuit point, and make the metal conductor of the conductor show traces of melting and denudation defects. This strong short-circuit arc and molten high-temperature metal can cause combustible material combustion. Because the conductor passing through the short-circuit circuit circuit current generates a lot of heat in a very short time, it will even cause the insulation layer of the conductor in the short-circuit circuit circuit to burn rapidly, and can cause the combustibles near the conductor to burn, thus causing a fire

(3) overload: the current passing through the guide line exceeds the safe current value. Because the wire itself has resistance, it will heat when passing current. The greater the amount of current passing, the greater the heat, and the higher the temperature of the insulation layer of the wire. Once the temperature of the insulated wire exceeds the maximum allowable working temperature, the insulation layer of the wire will accelerate aging, and even burn, causing fire accidents

(4) excessive contact resistance: at the connection of the power line and where the power line is connected with switches, protective devices and large electrical equipment, the local resistance of the contact part is too large due to poor contact. When there is a large current passing through the electrical circuit and the contact resistance is too large, great heat will be generated in its local range, which can make the metal change color or even melt, and cause the insulation layer of the electrical circuit, nearby combustibles and accumulated combustible dust to catch fire, causing a fire

(5) electric sparks and arcs. Electric spark is the result of discharge between electrodes, and the arc is composed of a large number of dense electric sparks. The temperature of the arc can be as high as 3000qc or above, and the electric spark and arc are easy to cause the combustion or explosion of combustible substances and fire

to sum up, many causes of electrical fires have common characteristics. First, the electric energy at the fault point or hot spot is converted into heat energy, generating high temperature or instantaneous high temperature. Second, the heating part ignites the surrounding combustibles. Therefore, we can use certain technical detection means to find and eliminate the fault points (hot spots) on the electrical lines or equipment in time, so as to achieve the purpose of preventing and reducing fire accidents

    2. Talking about the necessity of carrying out electrical fire prevention detection from the severe situation of electrical fires

in 1985, there were 5214 electrical fires in China, accounting for 14.9% of the total number of fires; In 1990, there were 7486 electrical fires in China, accounting for 23.9% of the total number of fires; In 1995, there were 10598 electrical fires in China, accounting for 28% of the total number of fires; In 2000, there were 31933 electrical fires in China, accounting for 26.1% of the total. In the past 15 years, electrical fires have been increasing in China. High precision reducer has the characteristics of stable transmission, low noise and long service life; The ratio of large LCD to the total number of fires is also high. From 1993 to 2000, there were 18 fires that killed more than 30 people in the country, including 6 electrical fires

the situation of electrical fire in China is severe, which certainly has the inevitable trend of economic development. However, compared with developed countries, the rate of electrical fire in China is also relatively high. According to the statistics of Japan from 86 to 90 years, the number of electrical fires accounted for only 2-3% of the total number of fires in the country, and the losses caused by electrical fires ranked eighth to ninth; AMEC explained that users will encounter problems that they cannot solve in the process of using and changing the experimental machine, and the occurrence rate of gas fire is not prominent. Therefore, we must adhere to the "prevention first", carry out extensive electrical fire safety testing nationwide, eliminate hidden dangers of electrical fires, and curb the rising momentum of electrical fires

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