Wind Deflection Risk Assessment Of UHV Transmission Lines

As China enters a new era,with the rapid economic development,the demand for resources and energy is increasing.According to the 13 th five-year plan,the new power transmission capacity of the project will reach 270 million kilowatts by 2020.Ensuring the normal operation of uhv transmission lines is of great importance to the power system.Wind deflection flashover is one of the important factors affecting the normal operation of transmission lines.Therefore,this paper takes wind deflection flashover of transmission lines as the main research object,and focuses on wind deflection influencing factors,wind deflection flashover risk assessment and line safety assessment analysis of transmission lines.The details are as follows:1.Through reading a lot of literature,the basic characteristics of transmission line wind deflection flashover are understood,and the classical calculation method of transmission line wind deflection flashover is learned;The finite element model of transmission line is established by ANSYS software,and the wind deflection Angle of the finite element model is calculated by applying wind load,and the advantages and disadvantages of the two methods are compared.2.The influence of wind speed,wind direction,wire parameters,pitch,height difference and line Angle on wind deflection flashover in the finite element model of insulator string is analyzed quantitatively with the help of the finite element model of transmission line;The effects of wind speed,wind direction,wire parameters,pitch and sag on wind deflection flashover are analyzed quantitatively.The effects of rainfall,fog,humidity and topographic conditions on wind deflection flashover of transmission lines are analyzed qualitatively.Finally,the importance of each factor is evaluated according to the analysis results.3.The insulator string finite element model is selected to combine 1600 working conditions according to the changes of wind speed,wind direction,wire parameters,pitch and height difference in the factors affecting wind deflection,and the wind deflection Angle of corresponding working conditions is calculated by using the finite element method.Based on the neural network algorithm,the risk assessment model of transmission line wind deflection flashover is established with 1600 working conditions and wind deflection angles as the data basis,and the reliability of the model is verified.4.The wind deviation risk assessment model based on neural network fails to consider the influence of fog,humidity and terrain conditions,which cannot be ignored.Therefore,the analytic hierarchy process(ahp),entropy weight method and ahp-entropy weight combination method are adopted to conduct line evaluation and analysis on various influencing factors,and a line evaluation and analysis model of wind deviation incidence rate of transmission lines is established.By using this model,the risk incidence rate of wind deviation can be calculated and the line safety level can be evaluated.Finally,the transmission lines are optimized.