Thermal Analysis And Safety Monitoring Of 10KV Power Cable Joints For Electrified Railway

Due to the complex operation conditions of the railway,large equivalent capacitance of the power cable line,excessive traction return and other factors,accidents such as aging and burning of the lOkV power cable joints of the railway frequently occur,which seriously threatens the railway traffic safety.The research on cable joints aging and on-line detection is very important to reduce the occurrence of cable accidents and ensure railway traffic safety.Therefore,this paper carries out heating analysis and safety monitoring research on power cable joints.Firstly,the temperature field simulation model of 10kV YJLV22-3*95mm2 three-core power cable joints is established by using the finite element analysis software ANSYS Workbench.Through thermal analysis of cable joints under ideal conditions,traction ground reflux and abnormal contact resistance,it is found that excessive traction ground reflux has a great influence on heat dissipation of main insulation,and abnormal temperature rise point will be formed at cable joints when contact resistance is abnormal.On this basis,according to the temperature limit of long-term stable operation of the cable,considering the effect of different ambient temperatures and traction ground backflow,the least square method is adopted to fit and analyze the temperature field simulation data,and the setting formula of the maximum current carrying value of the cable and the temperature monitoring threshold value is obtained,which provides theoretical basis for cable load adjustment,state determination and online monitoring.between cable grounding line current and cable insulation parameters and the measurement of cable main insulation dielectric loss are analyzed.During the development of cable j oints safety monitoring device,according to the main component of cable grounding line current as main insulation leakage current when no electric locomotive passes through the electrified section,AC synchronous sampling technology and signal processing are adopted to measure the tangent value of cable main insulation dielectric loss.The safety monitoring device transmits data information,state determination information and geographic coordinate information of cable j oints safety monitoring to a background server through network transmission,carries out safety monitoring and state determination on the cable joints,enables workers to grasp the running state of the cable joints in time,and provides decision basis for cable joints maintenance,abnormal condition processing and load adjustment.Finally,the function of the cable joints safety monitoring device is tested experimentally.The experimental verification shows that the device has good performance in various aspects such as data acquisition and calculation of state variables,call of cable running state criteria,key input control,geographic coordinate positioning and information transmission,etc.and meets the expected requirements.