Electrical performance: The insulation resistance between the shielding and shielding of the wire group is not less than 1MΩ, and the 1500V5min test between the km. wire core and the wire core and the wire core and the shielding does not break down. The working capacitance of the wire group is not more than 100Pt/m. The distribution inductance is not more than 0.4μH/m. The capacitance imbalance between the wire groups is not more than 250Pf/(250m).
(1) Cut off the power of the fired cable. When a cable catches fire, it should be cut off immediately regardless of the cause. Then, according to the path and characteristics of the cable, it is carefully checked to find out the point of failure of the cable. At the same time, personnel should be organized to save.
(2) Cut off the non-faulty cable power in the cable trench. When the cables in the cable trenches start to burn, if the cables laid side by side with the same trench have obvious fire potential, the power of these cables should be cut off. If the cable is arranged in layers, first cut off the heat-receiving cable power above the fire-retardant cable, and then cut off the cable power supply that is in parallel with the fire-cable cable, and finally cut off the cable power supply under the fire-breathing cable.
(3) Close the cable trench fire door. When the cable trench inside the cable catches fire, in order to avoid air circulation, in order to facilitate rapid fire extinguishing, the fire exit of the cable trench should be closed and extinguished by means of suffocation.
(4) Good personal protection when fighting a cable fire. Due to the fire of the cable, a large amount of smoke and toxic gas will be generated. When the cable fire is extinguished, the rescue personnel should wear antivirus. In order to prevent people from getting an electric shock during the rescue process, the rescue personnel should also wear rubber gloves and put on insulated boots. If high-voltage cables are found to be grounded in one phase, the fire-fighting personnel shall observe: Indoors shall not enter within 4m from the point of failure, and outdoor access shall not be allowed. Point within 8m so as not to hurt people by step voltage and contact voltage. The ambulance personnel are not limited to this, but protective measures should be taken.
(5) Fight fire extinguishing equipment used in cable fires. Fire extinguishers should be used to extinguish cable fires, such as dry powder fire extinguishers, "1211" fire extinguishers, and carbon dioxide fire extinguishers; dry sand or loess can also be used; if water is used for extinguishing fires, spray guns are preferred; if the fire is violent, it is not Other methods may be used to save the fire. After the power is cut off, water can be poured into the cable trench and the water can be used to seal the fault and extinguish the fire.
(6) When fighting a cable fire, do not touch the cable reel or move the cable by hand.
From the 11th Five-Year Plan period, China’s megacities began to use high-voltage, ultra-high voltage cable lines to penetrate urban load centers. During the 12th Five-Year Plan period, 220 kV cross-linked cables and a small number of 500 kV cable lines will enter the city center. The construction also requires the use of a part of 500 kV cables, but up to now, domestic 500 kV cables and accessories have been provided abroad. Although there are a large number of vertical tower production lines (VCV) in China, 500 kV cables and accessories cannot be manufactured completely. Research on high-voltage, ultra-high voltage cross-linked cables and accessories was included in the research project. The cable branch suggested that we should engage in relevant basic theoretical research work, design parameters, eliminate thermal stress, process requirements, inspection technology, accessory design and fabrication process of prefabricated parts, and try to produce 500 kV cross-linked cables and outdoor terminals as research priorities. GIS terminal samples, in order to ensure product quality and stability, to ensure that the application of engineering lay the foundation.
In addition to the above items, research on wire and cable material recovery technology, research on reliability and application of domestic composite reinforced core materials for high voltage overhead transmission lines, research on high solid content paint and coating processes, periodic load ampacity, and real-time current carrying capacity are also included. Twelve Five Research Projects.
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