As the application of cables becomes more and more widespread, cable electrical facilities due to various reasons often occur, causing great economic losses. For this reason, the fire protection split of the cable is on the agenda. It is necessary to do a good job in the fire prevention of cables and electrical facilities
1. The severity of cable fire
(1) A cable fire in a power plant in Shaanxi in 1973. The plant caught fire due to an oil leak in the steam turbine pipeline spreading to the cable. The fire destroyed the house frame of the steam turbine factory and all the main power control panels burned down. At that time, the direct loss was as much as 1.5 million yuan. It took a year to rebuild before power generation resumed.
(2) In 1984, there was a cable fire in Wuyang Iron and Steel Company. The cable in the basement of the main electric room of the rolling mill was on fire, which caused a direct loss of more than 1.6 million yuan.
(3) According to statistics, there were 3,282 electrical accidents in the United States during the 10 years of the mid-20th century (1965-1975). Cable fires accounted for 1/3, and the losses accounted for 40% of the US$100 million.
The reason and analysis of the fire of the cable quality problem
(1) The cable material is impure or unqualified, and the core wire of the cable is made of copper or aluminum conductor. The material for processing the cable core conductor should be high-quality electrolytic copper or electrolytic aluminum. After washing, it is processed into a bare copper (or bare aluminum) conductor with a specified diameter through multiple passes, and then passes through vacuum bright annealing to be qualified as a core wire into a forest. After passing through multiple windings or injecting insulation layers, shielding layers, and protection The sheathing and other processes are the finished cable products. Due to the impure core wire material and many impurities, the conductivity of the cable is reduced.
(2) The nominal cross-section of the cable core conductor does not meet the requirements. The core wire interface processed by the cable manufacturer is smaller than the nominal interface, because the current density of the unit is too large, which causes abnormal heating during the operation, which causes the cable to catch fire.
(3) The composition of the insulating material does not meet the requirements and the processing is poor. As a result, the cable withstands pressure drop during operation, the insulation resistance is unqualified, it is easy to accelerate aging and cracking, and it is easy to cause the cable to short-circuit and ground fault.
(4) The technology of the cable production process is poor. Some cable manufacturers do not strictly follow the process during the cable production process, or some manufacturers with poor production conditions are shoddy and shoddy, which will cause the quality of the cable to decline.
(5) Improper transportation is the damage of the cable. The original qualified cable is transported and unloaded improperly, causing the cable to be squeezed or impacted, the internal core wire is damaged, and the insulation layer is damaged.
In short, for online cable line electrical equipment, only by selecting good quality originals, installing them according to regulations, using them reasonably, maintaining them in a timely manner, strengthening fire protection awareness, improving the fire suppression system, and installing advanced fire protection and alarm devices, will cable fires be reduced. .