| Ice disaster of overhead transmission line is always a big problem threatening the normal operation of power grid in China.Blasting de-icing method is an efficient,economic and available de-icing method.In order to improve the safety performance and efficiency of blasting de-icing,we blasting de-icing by laying detonating cord on transmission line in this paper.In order to further improve the reliability of this method in engineering practice.In this paper,the safety and efficiency of the segmented blasting de-icing method are studied in detail by the combination of experiment and simulation.Firstly,ice samples with different densities were prepared by pressure sintering method.The dynamic compressive strength of ice samples with different densities under impact load is obtained by SHPB dynamic compression test.Combined with LS-DYNA numerical simulation,the crushing mechanism of ice sample under impact was analyzed to determine the accuracy of ice constitutive model.Secondly,the form-finding analysis of transmission lines is carried out by MATLAB calculation software combined with ABAQUS simulation software.The numerical simulation of detonating cord blasting was carried out by LS-DYNA,and the positive pressure time-history curve of shock wave during detonating cord blasting was obtained.Furthermore,the damage of ice particles flying out to the transmission line during the detonating cord explosion was analyzed.The results show that the ice splash of detonating cord has no damage to the transmission line.On this basis,combined with the section and whole section blasting de-icing test of the line within the 40 # ～ 41 # span of the 220 k V retired line of Pingfeng line,the test conditions are simulated by finite element software ABAQUS.The de-icing efficiency and displacement of segmented blasting and whole blasting were compared.The influence of segmented blasting and whole blasting on the hanging point tension of transmission line is further studied.The results show that compared with the whole segment blasting de-icing,the segment blasting de-icing achieves higher de-icing rate with smaller single initiation charge,and effectively reduces the jump amplitude of the line and the dynamic tension change amplitude at the hanging point.So sectional blasting de-icing is an efficient,safe and practical de-icing method.Finally,through the establishment of Pingfeng 220 k V single-span model and smooth 220 k V double-span line model.Combined with the design specifications of each line,the jump height amplitude,de-icing length,hanging point tension difference amplitude and dynamic tension amplitude of each line under different ice conditions are analyzed.The best de-icing scheme of single-span and double-span lines under three different types of ice is determined. |
