Power cable flammability, cascading nature, in the event of a fire, serious harm, especially in power plants and large substations, in the event of a fire, spread to other circuits. Therefore, the power cable fire prevention technology is one of the important technologies for the normal operation of the electrical system. Power cables are an important part of electrical engineering and their role is to transfer and distribute power. Power cable is composed of insulated core wire, insulation sheath and protective layer. In order to adapt to various complicated laying environments, power cables are designed with good insulation, waterproof and mechanical properties. However, when overcurrent occurs in the cable loop causing the cable to overheat, various properties of the cable change, creating a fire. This article intends to cable fire technology to make a little discussion. 1, create a good operating environment to avoid accelerated aging of cable insulation and damage Cable trench, cable tunnel to have good drainage facilities, such as the provision of shallow water ditch, water collection wells, and can effectively drain, if necessary, set up automatically start and stop pumping device to prevent water, keep the inside dry. Cable trench, the vertical drainage tunnel to maintain the slope. Prevent water, corrosive gases or liquids and flammable liquids or gases from entering the cable duct, cable tunnel. The cable tunnel should be naturally ventilated. When the normal load of the cable is applied, the air temperature in the tunnel should be higher than 40 ~ 50 ° C. Ventilation can be achieved by a combination of natural ventilation and mechanical ventilation. Ventilation fan system should be linked with the fire detector to ensure that the fire in the tunnel automatically stop the wind, the cable tunnel shall not be used as a ventilation system into the air duct. Cable fire doors should be avoided in the normally closed state, with a fire barrier to completely close the cable, cover the gap between the cable duct cover filling and other effects of cable ventilation and cooling practices. And the cable completely closed up, but also make the normal inspection of the cable becomes impossible, can not be found in time cable fault. According to statistics, due to the cable head failure caused by the cable fire, explosion accidents accounted for about 70% of the total cable accidents. Strict empty cable must be made of materials and process quality. Requirements of the life of the cable head made, not less than the life of the cable. The rated voltage level of the street and its insulation level shall not be lower than the rated voltage level of the connected cable and its insulation level. Insulation between the insulation pad on both sides of the pressure value, not less than 2 times the level of cable insulation insulation. The form of joints should be adapted to the environmental conditions set, and will not affect the flow capacity of the cable. Cables on both sides of the 2 ~ 3m range, should take the fire retardant tape for fire retardant extension treatment. In general, cables see through the weakness of cable insulation, so strengthening cable head monitoring and management is an important part of cable fire prevention. The terminal cable head must not be placed in the cable channel, cable tunnel, cable slot box, the middle of the cable between the cable layer must register and use a variety of testing equipment for testing. Found abnormal temperature rise or smell of the cable head, smoke, emergencies early exit operation, to avoid running the cable in the ignition. Between the middle of the cable head should ensure a sufficient safety distance, more than two cable head in the same position, the cable head and other cables should be taken between the strict sealing measures. 2, to strengthen the cable preventive test Cable After the installation of cables and cable accessories is completed, DC voltage withstand test should be conducted [preventive test]. The experimental data are compared and analyzed. That is, it can be compared with the experimental data of the same cable, and can also be compared with historical experimental data of this cable to explore the law of experimental data. If the DC withstand voltage test, the measured leakage current value of any of the following conditions, the cable insulation may be defective, reflecting the defect site, and be dealt with: (1), rising rapidly with the increase of test voltage or the increase of pressurization time (2), compared with the same cable to increase the value of more (3), compared with the previous cable measured data showed a clear upward trend (4), leakage current unbalance coefficient between three phases is larger. The above situation should be carefully analyzed, if not caused by improper test methods, you may be appropriate to increase the test voltage or extend the test time to determine whether the cable meets the conditions for continued operation. For the test standard of DC withstand voltage of power cables, see Chapter 17 of "Electrical Equipment Installation Engineering Standard for Handover of Electrical Equipment " (GB50150-91). Commonly used plastic insulated power cable DC voltage test value of 4 times the rated voltage of the cable test time is 15 minutes. 3, Strong on the cable head production quality management and operation monitoring. 4, to prevent ignition of other equipment, ignition cables Can ignite the cable ignition of oil-filled electrical equipment and coal, milling systems, gasoline engine system. They must take appropriate measures: cable duct cover near the oil-filled electrical equipment should be sealed, oil flow to the cable ditch in the textile equipment failure ignited the cable. Pulverized coal in the coal feeding and pulverizing system must be periodically cleaned to prevent the pulverized coal from naturally igniting the cables. Anti-rioting flour milling system against the cable fire tank box must have to prevent explosion-proof door action spray fire-retardant cables. [cnecPage] 5, with the closure, blocking, Tu, Bao and other measures to prevent the cable from burning Fire-retardant coating has a thin coating, does not affect the normal heat, while can play a good thermal insulation and other characteristics, but there are also many shortcomings. Including the selection of fire retardant coating varieties, the market in late fake and shoddy products practical application of poor results, there is peeling spit material surface peeling off, uneven coating thickness, cutting corners and so on. The fire protection coatings used in cable engineering are mainly solvent-based, solvent-based solvents have toxicity, price, transportation safety and environmental pollution problems. The application effects such as cold resistance, water resistance and oil resistance are not satisfactory. In particular, the bending resistance is not good, the coating has poor flexibility after curing, and is only suitable for fixing the erection of the cable. The coating is easy to crack and peel off. Therefore, the cable should not be a large number of ways of using fire-retardant paint brushing fire, but should be a large number of seals, plug, interval mode, should pay attention to the following questions: (1), with the seal, block, every method, to ensure that a single cable does not ignite fire on the multi-cable. Cable into the cable channel, cable tunnels, cable slot box, cable sandwich layer of the mouth to be closely sealed fire, to prevent a single cable or a small amount of fire on the cable and ignite a large number of cables. Cable trench, cable tunnel