Causes of the hottest cable fire accident

Reasons for cable fire accidents

cable fire accidents mostly occur in power production systems, especially in production places such as power plants and substations. This is because the cables used in these places are all over the corner and numerous, and they are densely laid in tunnels or overhead. Some cables are still in a harsh environment where improper use with high-temperature objects will cause the specimen to break at the fixture and cause the experiment to fail. They are close to parallel or staggered arrangement. In the cable interlayer room, the cable layout density is higher, and there is natural ventilation caused by the height difference of the cable shaft. Especially for the oil filled cable, its cable insulation is a flammable material with high calorific value, while the power cable is in a heating state during operation. Under these special conditions, whether the arc caused by the cable fault itself or the fire in the external environment of the cable will cause the cable to catch fire and quickly spread along it, causing disastrous consequences. It can be said that all major fire accidents at the production site of power plants and substations have affected the cable fire or expanded the fire accident through cable ignition. Therefore, it is very urgent and important to pay attention to cable fire prevention in power production site

to prevent cable fires, we must carefully analyze the causes of cable fires in order to formulate targeted anti accident countermeasures. The causes of cable fire accidents are summarized as follows according to the cable itself and external ignition

I. cable fire caused by cable failure

according to the case data collected by the author, the number of fire accidents caused by cable failure accounts for about 1/① of the whole cable fire accidents For ordinary metal and non-metal samples, the jaw of the fixture is in direct contact with the sample for about 3. The causes of cable failure are the following types:

(1) the cable head explodes and catches fire due to poor manufacturing quality of the cable head

(2) after long-term operation, insulation aging, breakdown, short circuit and fire of the cable

(3) poor cable laying conditions (high temperature or ponding) cause insulation decline, short circuit and fire

(4) insulation damage, short circuit and fire caused by external mechanical damage of cable

(5) the cable is overloaded for a long time, or the protective (SWITCHING) device cannot cut off the load short-circuit current in time, resulting in overheating of the insulation, damage and short-circuit fire of the cable

(6) the oil filled cable leaks oil and causes fire

second, the external fire of the cable ignites the cable, causing cable fire accidents

in the power production system, such accidents account for about 2/3 of cable fire accidents. The causes of the accident can be roughly divided into the following types:

(1) the deposition of pulverized coal from such a load will cause the steel strand to produce high strain rate ignition or be burnt and ignited and the cable to catch fire

(2) the oil of steam turbine and boiler (including fuel oil, lubrication and control oil system) is on fire, which affects the cable on fire

(3) the explosion of the pulverizing system caused the cable to catch fire

(4) electric and gas welding cutting metal slag pilot cable

(5) cable fire caused by electrical equipment failure

(6) other sundries cause the cable to catch fire

the case data shows that the number of cable fire accidents caused by powder deposition and oil system fire is more, accounting for about 2/5 of all cable fire accidents, and the consequences are mostly serious, which must be paid great attention to