Calculation Of Current Carrying Capacity Of Power Cable Based On Finite Element Method

Along with the continuous improvement of the mechanization and automatization of coal mine,power supply load shows a high-density increase.Under the circumstances,the safety and dependability of the operation of power supply system becomes quite outstanding.Power cable is an important carrier for power transmission and one of the basic parameters for cable performance is ampacity.When ampacity is pretty enormous,the cable may be overloaded,which may cause the temperature of the cable to increase and accelerate the aging of the insulation.In the end,the service life of the cable may be greatly shortened.Therefore,a new,finite element method-based method for calculating cable ampacity is particularly important.This thesis,first of all,summarizes the calculation methods for cable ampacity,and studies the development trend and current application situation of the calculation methods at home and abroad.By using of cable structure,loss parameter and the thermal parameter of laying medium,equivalent thermal circuit model of cable is constructed in accordance with thermal circuit principles so as to infer the calculation method for cable core temperature;the shortcomings of the calculation method in IEC-60287 standard are pointed out and improved in order to enhance the accuracy of the calculation value of cable core temperature;based on heat transfer theory,a finite element method-based calculation model for cable ampacity is built in combination with current cable-laying situation and the distribution model of the temperature field in cable trench is accomplished;on the basis of secant method,the method for calculating cable ampacity is proposed.ANSYS finite element analysis method is utilized to simulate the ampacity and temperature field distribution within 6-circuit cable trench with different laying.Besides,the high accuracy of cable ampacity calculation due to the application of finite element method is simulated and verified.In addition,the rules of cable ampacity and laying density are analyzed in order to optimize cable-laying manner based on the actual situation of projects.Finally,the factors affecting cable ampacity are analyzed and the changing rules of power cable ampacity under the influence of different factors,studied so as to provide theoretical support for the selection,which meets the specific requirement of system,of suitable cable-laying condition in actual projects.