Numerical Simulation Research On Ice Coating And Melting Process Of Transmission Line

The icing disaster will affect the reliability of the operation of the transmission line.As the icing of the transmission line increases,it will increase the load on the transmission line and cause damage to the electric power system.Therefore,predicting the thickness and shape of the ice on the power grid,and promptly taking ice-melting measures after the ice on the line is an effective way to ensure the safe operation of the power grid and reduce economic losses.Based on the theory of fluid mechanics combined with the theory of heat transfer,this paper firstly studies and perfects the heat balance equation of ice coating of the existing transmission lines,and studies whether it is reasonable to use simplified circular models instead of actual conductors at this stage,and establish circles respectively.Shape and stranded wire model,calculated the local collision coefficient of the circular model and the stranded model,the results show that: the local collision coefficient calculated based on the circular model is greater than the stranded model,resulting in the final ice cover and shape calculation results are quite different.Therefore,in order to ensure the reliability of the calculation results,the wire stranding model should be used.Analyze the thermal balance equation of the wire during rime icing,and combine with the physical process during icing,carry out theoretical analysis on the two important parameters that affect the line icing-collision coefficient and freezing coefficient,and study the influence of different environmental variables Under the influence of the local collision coefficient and freezing coefficient of the stranded wire model,the DPM model of the Fluent software is coupled with the multiphase flow model,combined with the local collision coefficient theory and the UDF is used to simulate the collision coefficient of the wire.The influence of environmental factors on the local collision coefficient is based on the simulation results of the local collision coefficient,and the influence of environmental variables on the ice cover and shape of the transmission line.Critical ice melting current and ice melting time are important parameters to measure the ice melting efficiency of ice-coated wires.Establish a thermal balance calculation model for the thermal balance of each part of the line during ice melting and the physical process of ice melting on the line,and study the influence of wind speed and ice thickness on the critical ice melting current of the conductor under the condition of rime ice coating.Using Fluent in the heat transfer module,the ice melting wire model is established to analyze the flow field around the wire and the temperature of the ice layer;based on the determination of the critical ice melting current,the heat change required for melting of the ice layer is calculated to obtain the required ice melting.the influence of wind speed,ice thickness and melting current on the melting time is further explored;the thermal balance model of the ice coating and melting ice of the wire is combined to establish a model for the case of ice melting during ice melting,based on when the ice melting speed is greater than the ice coating speed,the ice melting can be the theoretical basis,and the critical current and the ice melting time can be derived.