The Development Of Multiparameter Online Monitoring Device Based On 4g Network Communication For Railway Power Cable Joints

Along with the rapid development of electrified railways,the use of power cables in railways has increased,while a series of problems such as cable fault and burning out of cable joints affect the safe running and normal operation of railways directly,and seriously affect the personal and property security.For this kind of situation,a multi-parameter on-line monitoring device for power cable joints along railways was developed based on 4G network communications in this paper,which realizes the simultaneous acquisition of 5 parameters,including outer sheath temperature of cable joint,grounding current,induced voltage of metal sheath,ambient temperature and humidity.The new monitoring device is of great significance in reducing fault probability of cable and guaranteeing safe operation of the railway.Firstly,the finite element analysis software Ansys was used to conduct electro-thermal coupling simulation of the YJLV22-3*95mm2 type XLPE cable commonly used in the railway line.By adopting the method of control variables,the cable core temperature is fixed as the maximum operating temperature allowed by XLPE cable in the long run,so as to obtain the maximum allowable temperature of outer sheath corresponding to different environmental temperatures.If the collected temperature of the outer sheath exceeds the calculated value,the abnormal heat inside the cable will be proved.Based on this,alarm criteria can be provided for the monitoring devices studied herein.Secondly,the collection principle and necessity of the monitoring device were expounded,anda multi-parameter online monitoring device for railway power cable joints based on 4G wireless network communications was developed as well.The device could transmit the data to the background management system via 4G network,and send the data to the relevant operatcors' mobile phones in the form of short messages at the same time.The operation status of the cable joints shall be monitored online,and abnormal operation status shall be prompted by voice and SMS alarm,so that operators can timely grasp the cable status,take preventive measures in advance and adjust the cable load.At last,multiple linear regression was used to process the data collected by this device and a quaternary linear regression model between outer sheath temperature of cable joint,and grounding current,induced voltage of metal sheath,ambient temperature and humidity in operation state was achieved.This regression model can be used to distinguish whether the abnormal monitoring data is invalid due to loose sensor installation or malfunction,and improve the validity judgment of data collection and reliability of cable head abnormal alarm.