Research On The Key Parameters Of The Ice Growth Model On Overhead Transmission Lines

Ice coating on overhead transmission lines is a common natural phenomenon and one of the most serious threats to disrupt the stable operation of power systems.Studying the characteristics of key parameters of ice coating growth is of great significance to the prediction and prevention of ice coating on transmission lines,but the fact that there are many factors affecting the actual transmission line,and some unconventional meteorological parameters are difficult to obtain,many research methods of theoretical models are limited in application.This article aims at the key parameters of icing growth of the wire(water droplet collision coefficient and freezing coefficient),from the analysis of the icing type based on the characteristics of the key parameters of icing growth,the study of the key parameters of the icing growth of overhead transmission lines,and the environmental factors affecting the key parameters of icing growth,which has enriched the theoretical research of transmission line ice coating.Its methods and ideas have certain theoretical value and engineering application value.Based on the principles of fluid mechanics,the FLUENT software is used to establish a wind tunnel model of wire icing,determine the control equations,turbulence equations,boundary conditions and solving methods of the air flow field,and calculate the distribution characteristics of the air flow field of the wire and the water droplet collision of the wire icing characteristic.The freezing coefficient model is established according to the heat balance process of the wire icing.The freezing coefficient model is established according to the heat balance process of the wire coating.Based on the collision coefficient,freezing coefficient model and the critical conditions of rain and rime,the relationship between the ambient temperature and the liquid water content of the air under the critical conditions of glaze and rime with external environmental factors is obtained.These curve relationships are used to preliminarily determine the type of ice coating formed under different environmental conditions.Combined with the calculation model of the icing growth of the overhead transmission line,the Makkonen icing growth model and the icing heat balance model,based on the icing monitoring mechanical parameters(tension,inclination and wind deflection)of the transmission line and meteorological parameters(temperature,air liquid water content,wind speed and wind direction),a calculation model of the key parameters of the icing growth of the actual overhead transmission line is proposed,and the key parameters of the icing growth of the overhead line during the icing growth period are calculated from the actual transmission line monitoring data and micro-meteorological data.The artificial ice coating test was carried out in the low-temperature ice coating laboratory of South China University of Technology,and different environmental conditions were designed to conduct the ice coating test of the cylindrical steel pipe simulated conductor.The maximum relative error between the test results and the model results is within 20%,the model calculation results and the test results are in good agreement,which proves the validity of the key parameter model of ice growth.A generalized additive model(GAM)was used to establish a nonlinear response model of environmental factors to the key parameters of ice coating growth.The optimal GAM model was selected based on the AIC criterion,and the mathematical relationship between the collision coefficient and freezing coefficient of ice coating growth and environmental factors was analyzed.Combining the dimensionless data processing,the determination of the resolution coefficient and the correlation coefficient,the improved entropy weight method and the gray Euclidean correlation,an improved gray correlation analysis model was proposed to study the correlation between key parameters of ice growth and environmental factors.The non-linear relationships and correlations between the key parameters of icing growth and wind speed,wind direction,ambient temperature and air liquid water content were determined.