Study On The Temperature Increase Model Of High Voltage Overhead Conductor Considering Wires Rupture Besed On Thermoelectric Analogy And Parameter Identify

The local line temperature rises abnormally in the occurrence of the rupture of one or more of its aluminum wires,considering effects of poor operational conditions such as wind vibration,lightning,icing and flashover.Since some problems are closely related to the operating temperature of overhead conductor include creep annealing,material deterioration,line sag calculation and operational life prediction,building the temperature model of high voltage overhead conductor considering rupture of aluminum wires is helpful to evaluate the influence of wires breakage and self heating on conductor running state and provides the necessary theoretical basis for the further study of the problems,which is of great significance to the developments of state monitoring of high voltage transmission line and disaster reduction and prevention technology.There are some research on the calculation models of conductor temperature,however,the existing models are mainly established for undamaged conductor.The existing models have many parameters and they are difficult to obtain,and the empirical formula is used in calculating,so that there are some certain errors in the calculation results.Besides that,the existing models do not deal specifically with conductor temperature increase in the event of rupture of aluminum wires.The electrical parameters and thermal parameters of conductor vary after aluminium wires are fractured.Therefore,this paper takes related research.In this work,the experimental platform of high voltage overhead conductor considering wires rupture is designed,including ACSR LGJ-120/25 and LGJ-240/30.Under different current levels and temperature conditions,the resistance of broken and undamaged conductor is measured,and the nonlinear characteristic of AC resistance is analyzed.In order to accurately calculate the AC resistance of broken conductor,a mathematics model of conductor AC resistance considering wires rupture is established,and the model accuracy is verified.On this basis,the temperature increase model of high voltage overhead conductor considering wires rupture based on the thermoelectric analogy theory is proposed.The current-temperature experiment of LGJ-120/25 and LGJ-240/30 is carried out with different current levels under the condition of different strand number rupture using the experimental platform of high voltage overhead conductor considering wires rupture.In order to overcome the problem that model parameters are difficult to be obtained,the parameters are identified through experimental data,and the rule of the model parameters dependency of the increasing rupture of aluminum wires is analyzed.Through experimental analysis,the results of temperature increase model developed by this work are in good agreement with experimental data,and the error of the model is small,which can accurately describe the thermal dynamic process of overhead conductor temperature increase in the event of rupture of aluminum wires.