Due to the atmospheric circulation anomalies and La Nina events affecting the common, since January 10 this year, China Southern and northwestern provinces suffered a rare 50 years of disastrous weather, continuous cryogenic freezing rain and snow weather extremes to Guizhou, Hunan, Jiangxi, Anhui and other 16 provinces (autonomous regions and municipalities) production and life brought serious influence, power transmission lines icing is a serious, emergence of transmission and distribution lines large area pressure off. How to strengthen and improve the transmission line anti icing ability, to ensure the safety of electrical wiring, reliable, economic operation, related to social and economic stability and development, people live and work in peace and contentment.
In general, there are three kinds of icing on the grid lines. First is a small amount of ice, it on the wire circular section of the icing not uniformly package in the above, it may formed a elliptic or form other shapes, in the atmosphere constitute a windward surface, when the angle of wind and ice on the windward side right angle when the conductor will be dancing. The second case is that the flash Road, the structure is not damaged, but its insulation is lost, a road, electric send out. The third is the most common, because the vertical load is overweight, the whole structure collapse.
For the weather is cold and wet in the south, icing seriously affects the safe operation of the transmission line, icing brought harm to the safety in production, and increase the maintenance workload and increases the cost of the enterprise. Therefore, it is necessary to avoid and prevent the harm caused by ice disaster to transmission line, and it is a subject that must be faced by electric power and cable enterprises. Only to take measures to actively control the grid ice disaster.
1, the transmission line path should avoid the mountain wind and forest. In winter, alpine air due to the special geographical location, temperature is lower, the wind is also larger, are more likely to on the wire ice formation, ice thickness is usually lots relatively to much thicker, and therefore is weak zone of the transmission line. Forest areas in the south of China, because the trees grew very fast, and sometimes the line patrol line member not found in a timely manner and in some trees covered with ice or snow, trees that bear weight without shelter, will be backward transmission line, to the operation of the line caused a serious accident, likely to cause large area down the tower (rod) break.
2, to strengthen the daily maintenance of transmission lines. Line inspection line in the high voltage transmission line patrol carefully observe the power line may exist problems: such as the position of the cable, the tightness of the steel wire clip bolt, check cable, wire insulator in good condition, the growth height of trees within the channel line, this can also timely found the problem, timely deal with the problems found and avoid occurrence of tower falling down and down the rod and wire breakage.
3, improve the quality of power grid planning and design. Extensive research is required on the power grid planning and design stage, clear grid after a regional history of icing disaster situation, determine the right to resist the icing disaster of standard. China State Grid Corp announced in March 1, 2008, will adjust the power grid design, construction enterprise standards, to improve the power grid in a wide range of anti ice capacity. According to the State Grid Corporation announced the relevant adjustment programs: 35 to 330 kilovolt power grid fortification standards by once in 15 years increased to once every 30 years, 500 kilovolt power grid fortification standards by once in 30 years to once in 50 years, 750 kilovolt power grid fortification standard 50 years of the worst, is building a special high-voltage engineering disaster prevention standard 100 years once.
Wire and cable industry for electric power company is a major supplier, placed in front of the cable companies urgent task is the complete analysis of the wire break in the accident for a variety of reasons, in order to find a suitable solution to China's national conditions.
1, increase the strength of the research and development of overhead wires. Over the years, anti ice wire, self damping conductor, conductive wire with low noise, high strength wire and so on nouns, appeared in a variety of newspapers and periodicals, dizzying, thunder, but really in China's power grid application is almost gone.
2, the use of technical measures to prevent power grid icing. The existing technologies include thermal melting technology, over current melting ice technology, short circuit thawing technology and so on. Short circuit de icing technology including without load of three-phase short-circuit ice melting technology, and wire to wire two-phase short circuit melting ice technology, wire to wire single-phase short-circuit ice melting technology, and the traditional load ice melting technology, the use of dielectric loss in addition to ice technology, the short-circuit electromagnetic force de icing technology.
