Dynamic Response Analysis Of Deicing Of Overhead Transmission Lines

In order to analyze the jump displacement of overhead transmission line under different conditions of icing shedding and to find a reasonable way of icing shedding,the icing simulation system,the icing shedding control system,the displacement measurement system and the tension measurement system are designed.95 different simulating experiments of icing shedding conditions are carried out on the single strain section two span conductor of Linfen Electric Power School.The deicing jump displacement of the two span conductors under various working conditions was obtained and simulated by finite element software.The results show that,in order to minimize the jump displacement of deicing,The two span conductor should be selected for deicing at the same time,and the order of deicing in the span is first de icing at both ends and then de icing in the middle.A novel form-finding analysis method named unstressed initial length method was suggested in this paper to improve the disadvantages of traditional approach such as complicated steps,low computational efficiency and convergence.Based on the catenary equation,the initial length at no stress condition and the finial deformation of the transmission line were calculated as the initial parameters in finite element analysis.Then deformation process of the transmission line was equivalent to the effect of temperature and the specific load.On this basis,the form-finding analysis of transmission line before or after icing could be acquired by applying the temperature and the specific load onto the linear FE model.Subsequently,this method was well verified by the measurements of sage and tension of iced transmission line in field experiment.Finally,comparison of numerical simulations of the experiment by using this method,direct iteration method and small elasticity modulus method was conducted with and without icing.The error evaluation suggested that the unstressed initial length method exhibited considerable accuracy as the small elasticity modulus method.However,the analysis consistency and computational efficiency of unstressed initial length were much higher than the traditional methods.This research could help to provide new approach for the form-finding analysis of icing transmission lines.The actual line of Linfen electric power school is also simulated,and the validity of the test results is verified by simulation.The conclusion is as follows according to the simulation,The deicing of one line in a single tension section has little influence on other lines;and multiple lines can be considered to deicing at the same time to improve the efficiency;the jump height and static load displacement in the conductor span form a linear relationship,the equation are obtained by fitting the jump height and static load position of movement,the equation can be used to calculate the amount of deicing in order to reduce the jumping height is small.